JP7433710B2 - Fall prevention mechanism - Google Patents

Description

The present invention relates to a mechanism for preventing falls from a bridge when transferring from a ship to an offshore facility.

A movable pier is known that attempts to maintain stability by suppressing the oscillation of a bridge girder when transferring from a ship to an offshore facility in a wave environment (see Patent Document 1).

This movable pier is a movable pier equipped with a top plate supported by a 6-degree-of-freedom motion base and a bridge girder section extending laterally from the top surface of the top plate, and the bridge girder section is made up of a plurality of divided bodies. connected in the longitudinal direction, at least one horizontal rotation mechanism that connects the longitudinally adjacent divided bodies, and at least one vertical rotation mechanism that connects the longitudinally adjacent divided bodies, The divided bodies connected via the horizontal rotation mechanism can be rotated in the horizontal direction around the horizontal rotation mechanism, and the divided bodies connected through the vertical rotation mechanism can be rotated in the vertical direction around the vertical rotation mechanism. Furthermore, a magnet installed at the tip of the bridge girder can be attached to an offshore facility by adsorption.

Japanese Patent Application Publication No. 2015-137451

By the way, if a sudden wave of disturbance occurs, there is a risk of damaging the tip of the bridge girder or the connection between the divided bodies because the tip of the bridge girder is connected to the offshore equipment using magnets. In that case, there is a problem that the worker who is trying to transfer may fall or the tip of the bridge girder may collide with offshore equipment.

Therefore, the present invention has developed a fall prevention system that can prevent the tip of the bridge from separating from the target equipment even when instantaneous and irregular waves occur, thereby preventing workers from falling and collisions with the tip of the bridge. The purpose is to provide a mechanism.

In order to solve the above-mentioned problem, the invention according to claim 1 provides a cross-linking device having a table and a cross-link whose one end on the table side is supported by a shaft and which tilts upward and downward with respect to the table. A parallel link that is arranged parallel to the longitudinal direction of the bridge, and whose one end on the table side is supported by an axis, and tilts upward and downward while remaining parallel to the longitudinal direction of the bridge. and is rotatably connected to the other end of the bridge and rotatably connected to the other end of the parallel link, so that when the bridge and the parallel link tilt, the angle of inclination with respect to the horizontal direction is constant. with a tilt adjustment link that is maintained;
The bridge is provided on the other end side of the bridge so as to be able to tilt upwardly and downwardly, and the angle of the downward tilt with respect to the horizontal direction is limited by a member connected to the tilt adjustment link or a portion connected to the tilt adjustment link. and a tip step that changes the angle of upward inclination in response to contact with the target equipment to prevent a collision with the target equipment.

The invention according to claim 2 is characterized in that in the fall prevention mechanism according to claim 1, the angle of the downward inclination of the tip step is limited by a flexible member connected to the inclination adjustment link. shall be.

The invention according to claim 3 is the fall prevention mechanism according to claim 1 or 2, in which the one end of the parallel link is moved along the longitudinal direction of the parallel link to a desired position. The method is characterized in that it has a mechanism for fixing at , and the angle of the downward inclination of the tip step is adjusted by changing the inclination angle of the inclination adjustment link via the parallel link.

The invention according to claim 4 is the fall prevention mechanism according to claims 1 to 3, wherein the bridge is provided with a handrail, and the handrail is arranged on the other end side of the bridge at an upper end thereof. It is characterized by having an inclined frame connected to the frame and inclined downward.

The invention according to claim 5 is the fall prevention mechanism according to claims 1 to 4, which includes a light and a speaker that operate in conjunction with whether or not the tip step is in contact with the target equipment. It is characterized by comprising at least one of the above.

The invention according to claim 6 has a bridge whose one end is supported, and a bridge which is provided on the other end side of the bridge so as to be able to tilt upwardly and downwardly, and while the angle of the downward tilt with respect to the horizontal direction is limited. a tip step whose upward inclination is not limited; a tilt control member fixedly attached to the tip step and inclined upward with respect to the horizontal direction; and the bridge of the upwardly inclined tip portion of the tilt control member. a moving member attached to the opposite side of the tilting control member, and the tilting control member is configured to cause the moving member to move upward on the surface of the target equipment when the bridge approaches and hits the target equipment. The distal end step is tilted upward .

The invention according to claim 7 is characterized in that a cushioning material is attached to a side of the tilt control member opposite to the bridge.

According to the invention described in claim 1, when the tip of the bridge (the end opposite to the table) moves upward with respect to the target equipment due to the influence of waves, the member connected to the inclination adjustment link or The function of the connecting parts prevents the tip step provided at the tip of the bridge from tilting downwards beyond a predetermined angle of inclination, making it easier for workers to place their feet on the tip step when attempting to move to the target facility. This prevents personnel from losing their balance or misstepping and falling from the tip of the bridge, which in turn makes it possible to improve safety. In addition, if the tip of the bridge moves downward with respect to the target equipment due to the influence of waves, the tip step provided at the tip of the bridge will not be restricted from tilting upward, but the tip step will tilt upward. This prevents the upward inclination angle of the tip step from changing freely depending on the contact between the tip step and the target equipment, thereby preventing a collision situation. It becomes possible to prevent damage.

According to the invention set forth in claim 2, it is possible to configure a mechanism for limiting the downward inclination angle of the tip step in a relatively simple manner.

According to the third aspect of the invention, since the angle of the downward inclination of the tip step can be adjusted, the angle of the downward inclination of the tip step can be appropriately adjusted depending on the conditions related to the bridge construction device and the target equipment. , it becomes possible to improve ease of use and versatility.

According to the invention set forth in claim 4, the handrail has a frame that slopes downward on the tip side of the bridge and is formed in a shape without a right angle part, so that when the bridge slopes downward, The upper part of the handrail does not protrude forward, making it possible to prevent the handrail from hitting the target equipment and damaging the equipment, or from causing the worker to be caught between the handrail and the target equipment. Become.

According to the invention set forth in claim 5, it is possible to clarify whether or not the tip step is in contact with the target equipment, thereby making it possible to further ensure the safety of workers.

According to the invention set forth in claim 6, when the tip of the bridge contacts/collides with the landing target equipment in the front and back direction due to the influence of waves, etc., the upward tilt assist mechanism (particularly the tilt control member) operates. As a result, the tip step tilts upward together with the tilting control member provided at the tip of the bridge, thereby preventing a force from being applied to the tip step that would cause the tip step to tilt further downward than the downward angle. Therefore, it is possible to prevent damage to the tip step and landing target equipment.

According to the seventh aspect of the invention, since the tilting control member does not directly contact or collide with the target equipment, it is possible to prevent damage to the tip step and the landing target equipment.

1 is a side view showing the overall structure of a bridging device equipped with a fall prevention mechanism according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the crosslinking device shown in FIG. 1. FIG. FIG. 3 is a schematic diagram illustrating the operation of the fall prevention mechanism according to the first embodiment, and is a diagram showing a state in which the longitudinal direction of the bridge is along the horizontal direction. 4 is a schematic diagram illustrating the operation of the fall prevention mechanism shown in FIG. 3, and is a diagram showing a state in which the bridge is tilted upward. FIG. FIG. 4 is a schematic diagram illustrating the operation of the fall prevention mechanism shown in FIG. 3, and is a diagram showing a state in which the bridge is tilted downward. FIG. 4 is a schematic diagram illustrating the operation of the tip step of the fall prevention mechanism shown in FIG. 3, in which (A) is a diagram when the tip step is in a downward angle posture with the flexible member stretched; (B) ) is a diagram showing a state in which the tip step runs aground on an offshore facility and tilts upward. 4 is a diagram illustrating how to adjust the descending angle of the tip step of the fall prevention mechanism shown in FIG. 3, (A) is a diagram showing a state in which the tip step is tilted downward, and (B) is a diagram showing the tip step being tilted downward. FIG. It is a figure which shows a horizontal state. It is a side view of the fall prevention mechanism based on Embodiment 2 of this invention. FIG. 9 is a perspective view of the fall prevention mechanism shown in FIG. 8; 9 is a bottom view of the fall prevention mechanism shown in FIG. 8. FIG. FIG. 3 is a schematic diagram illustrating the operation of the fall prevention mechanism according to the first embodiment. It is a schematic diagram explaining the operation|movement of the fall prevention mechanism based on Embodiment 2, and is a figure which shows the state where the front side wheel is contacting the landing target equipment. It is a schematic diagram explaining the operation|movement of the fall prevention mechanism based on Embodiment 2, and is a figure which shows the state where the rear side wheel is contacting the landing target equipment.

The present invention will be described below based on the illustrated embodiments. In the following description, the front-rear direction, left-right direction, and up-down direction are defined according to the arrow directions shown in each figure.

This fall prevention mechanism 1 is installed on a bridging device 10 used when a worker transfers from a ship to an offshore facility, for example. Note that specific examples of the offshore facility include an offshore wind power generation facility installed on the ocean, an undersea mineral drilling platform, and the like.

The bridging device 10 equipped with the fall prevention mechanism 1 is not limited to one having a specific form or function, and various bridging devices having a bridge built between a ship and a landing target of an offshore facility can be used. can be selected. In the embodiment described below, a fall prevention mechanism 1 is installed in a bridging device 10 whose overall structure is shown in FIGS. 1 and 2. The bridging device 10 according to the embodiment below includes an agitation correction mechanism 11 installed on the deck of a ship, a main table 12 installed above the agitation correction mechanism 11, and a bridging device connected to the main table 12. 14, and a swing operation mechanism 17 that tilts (swings) the bridge 14. Note that the longitudinal direction of the bridge 14 is the front-back direction. Further, in the embodiment described below, the fall prevention mechanism 1 is provided on the left side of the bridge 14 of the bridge construction device 10, and the swing operation mechanism 17 is provided on the right side, but the fall prevention mechanism 1 is provided on the right side of the bridge 14. 1 may be provided, or a pair of left and right fall prevention mechanisms 1 may be provided on the left and right sides of the bridge 14.

The oscillation correction mechanism 11 has a hexapod type configuration and is a mechanism for correcting the sway of the ship body due to waves and maintaining the main table 12 horizontally. The sway correction mechanism 11 includes a base frame 111 that is fixedly installed on the deck of a ship, one end of which is connected to the base frame 111 via a universal joint, and the other end of which is connected to the main table 12 via a universal joint. It has six extendable actuators 112.

The base frame 111 is formed using, for example, a steel material, and is firmly fixed and installed on the deck of a ship.

Each actuator 112 is configured by, for example, an electric cylinder, and is controlled by a control device (not shown) to extend and contract.

With the six actuators 112, the oscillation correction mechanism 11 operates as a six-axis system with six degrees of freedom. Specifically, the oscillation correction mechanism 11 controls the main table 12 by detecting the oscillation with a control device and controlling the expansion and contraction of each actuator 112 when the ship oscillates in the front-rear, left-right, and up-down directions due to waves. Works to keep it level.

The main table 12 is formed into a polygonal plate shape when viewed from above, and is supported so that the direction and degree of inclination of the plate surface can be controlled by expansion and contraction of the six actuators 112 of the oscillation correction mechanism 11. In the illustrated example, an auxiliary table 121 is attached to expand the space above the main table 12. The main table 12 and the auxiliary table 121 are preferably formed to be lightweight, for example by using an aluminum frame or adopting a honeycomb structure.

A table handrail 13 is attached to each of the left and right edges of the upper surface of the main table 12 and the upper surface of the auxiliary table 121, spanning the main table 12 and the auxiliary table 121.

The bridge 14 functions as a passage spanning between the main table 12 and the landing target of the offshore facility, and is formed in the shape of a long plate.

The end of the bridge 14 on the main table 12 side (i.e., the rear end) is axially supported via a bridge rear end rotating shaft 16 disposed along the left-right direction, and is connected to the front end of the main table 12. Rotatably connected. As a result, the bridge 14 can be tilted upward with respect to the plate surface of the main table 12 (in this case, tilted at an elevation angle when viewed from the main table 12) and downward with the bridge rear end rotating shaft 16 as the center of rotation. It is attached to the main table 12 so that it can be tilted (in this case, it is tilted at an angle of depression when viewed from the main table 12). It is preferable that the bridge 14 be made of lightweight material such as aluminum or fiber-reinforced plastic.

Bridge handrails 15 are attached to the left and right edges of the upper surface of the bridge 14, respectively. The bridge handrail 15 includes a horizontal frame 15a disposed at the upper end, a first inclined frame 15b connected to the front end of the horizontal frame 15a and inclined downward, and a first inclined frame 15b connected to the front end of the first inclined frame 15b and further inclined downward. It has a second inclined frame 15c which is inclined to . That is, in the embodiment described below, the bridge handrail 15 does not have a shape in which the front portion has a right-angled portion where the horizontal frame at the upper end and the vertical frame at the front end intersect, but the frame 15b slopes downward. 15c, it is formed into a shape having no right angle portion. Note that the first inclined frame 15b and the second inclined frame 15c are preferably disposed within the reach of a worker who is placing his or her feet on the tip step 2. Further, the number of downwardly inclined frames is not limited to two, and may be one, or three or more frames. Furthermore, the downwardly inclined frame is not limited to a straight line, but may be curved.

The swing operation mechanism 17 moves the bridge 14 to the main table 12 so that the tip of the bridge 14, which moves up and down in response to the shaking of the ship due to waves, does not collide with the landing target of the offshore facility or move far away from the landing target. This is a mechanism for tilting operation relative to the angle of view. The swing operation mechanism 17 has an operation arm 18 and a drive device 19 that operates the operation arm 18.

The operating arm 18 is formed in a chevron shape (in other words, an upside-down V-shape) with a bent portion 18a in side view, and includes a first arm 18b on the front side and a second arm 18c on the rear side with the bent portion 18a in between. has. The tip (lower end) of the first arm 18b is fixedly attached to a position near the center in the longitudinal direction of the bridge 14, and the tip (lower end) of the second arm 18c rotates around the bridge rear end rotation shaft 16. possible to be connected.

The drive device 19 is a drive source for operating the operating arm 18 to tilt the bridge 14 with respect to the main table 12 . The drive device 19 is constituted by, for example, an electric cylinder, and is controlled by a control device (not shown) to extend and contract, thereby rotating the operating arm 18. The drive device 19 includes a cylinder tube 19a and a piston rod 19b that can freely move forward and backward with respect to the cylinder tube 19a.

The drive device 19 is arranged to be interposed between the main table 12 and the bent portion 18a of the operating arm 18. The cylinder tube 19a of the drive device 19 has its rear end tilted with respect to the upper surface of the main table 12 with the piston rod 19b side facing upward, and the cylinder tube 19a is oscillated via a rotation shaft arranged along the left-right direction. Can be attached freely. The tip of the piston rod 19b of the drive device 19 is rotatably connected to the bent portion 18a of the operating arm 18 via a rotation shaft arranged along the left-right direction.

When the drive device 19 contracts, the bent portion 18a of the operating arm 18 is pulled toward the main table 12, and the operating arm 18 is moved around the tip of the second arm 18c connected to the bridging rear end rotating shaft 16. rotates, and the bridge 14 to which the tip of the first arm 18b is fixed tilts upward relative to the plate surface of the main table 12.

On the other hand, when the drive device 19 extends, the bent portion 18a of the operating arm 18 is pushed out from the main table 12 side, and the operating arm is moved around the tip of the second arm 18c connected to the bridging rear end rotating shaft 16. 18 rotates, and the bridge 14 to which the tip of the first arm 18b is fixed tilts downward with respect to the plate surface of the main table 12.

When the ship is rocked in the vertical direction due to waves, the rocking operation mechanism 17 detects the rocking by the control device and controls the expansion and contraction of the drive device 19 so that the tip of the bridge 14 can be moved ashore to the offshore facility. It operates to prevent collision with the target or straying too far from the landing target.

The control device controls each actuator 112 of the oscillation correction mechanism 11 and the drive device 19 of the oscillation operation mechanism 17 in response to the sway of the ship due to waves, thereby maintaining the main table 12 horizontally. A mechanism will be provided to maintain an appropriate distance between the tip of the vessel and the landing target of the offshore facility. The height of the tip of the bridge 14 is mainly adjusted by the swing operation mechanism 17 while the main table 12 is maintained horizontally by the oscillation correction mechanism 11.

The mechanism for manipulating the postures of the main table 12 and the bridge 14 is not limited to a specific mechanism, and various mechanisms may be selected. As such a mechanism, for example, a mechanism that performs non-contact sensing using a ranging sensor may be selected.

In non-contact sensing, for example, a laser sensor (not shown) as a distance measurement sensor is installed at the tip of the bridge 14, and the distance to the landing target of the offshore facility is measured by the laser sensor. It is configured to work in conjunction with a control device to maintain an appropriate distance between the target and the landing target of the offshore facility. Specifically, the distance is a distance in the front-rear direction, a distance in the left-right direction as a distance in the horizontal direction, and a distance in the up-down direction (that is, a height difference).

The control device attempts to maintain an appropriate distance between the tip of the bridge 14 and the landing target of the offshore facility, for example, by repeatedly performing the following process at predetermined time intervals.
1) Compare the distance in each direction (i.e., front-back, left-right, and up-down direction) between the tip of the bridge 14 and the landing target of the offshore facility measured by a laser sensor and the allowable range in each direction. do.
2) If the distances in each direction measured above are outside the allowable range, the operation of the oscillation correction mechanism 11 and the swing operation mechanism 17 are necessary to bring the distances in each direction within the allowable range. Compute the operation of.
3) Based on the result calculated above, a drive instruction signal is output to either or both of each actuator 112 of the oscillation correction mechanism 11 and the drive device 19 of the swing operation mechanism 17.

In particular, if the distance in the front-rear direction is outside the permissible range in the front-rear direction or the distance in the left-right direction is outside the permissible range in the left-right direction, a drive instruction signal is output to the sway correction mechanism 11 to move the six axes. each actuator 112 is driven. On the other hand, if the distance in the vertical direction is out of the permissible range in the vertical direction, a drive instruction signal is output to the swing operation mechanism 17 to drive the drive device 19.

Note that the permissible range in each direction is not limited to a specific value; for example, the upper and lower limits may be set as appropriate after taking into consideration various conditions such as ships, offshore facilities, wave conditions, etc. be done.

Here, due to the limits of the performance of the control device and the drive device 19, in response to the rocking of the ship body due to irregular and sudden waves, the tip portion of the bridge 14 is moved instantaneously to the vertical movement of the tip portion of the bridge 14. It is difficult to always maintain a constant vertical distance (i.e. height difference) between the facility and the landing target. If the distance in the vertical direction changes, the height difference between the tip of the bridge 14 and the landing target of the offshore facility will change, causing the worker to lose balance, misstep, or even fall. Furthermore, there is a risk that the tip of the bridge 14 may collide with the offshore facility.

(Embodiment 1)
Therefore, the fall prevention mechanism 1 according to this embodiment includes a main table 12 and a bridge 14 whose one end on the main table 12 side is supported by a shaft and which tilts upward and downward with respect to the main table 12. This is a fall prevention mechanism 1 that is installed in the crosslinking device 10, and is arranged parallel to the longitudinal direction L14 of the bridge ₁₄ , and one end on the side of the main table 12 is supported by a shaft, so that it is parallel to the longitudinal direction _L14 of the bridge 14. The parallel link 4 is rotatably connected to the other end of the bridge 14 and is rotatably connected to the other end of the parallel link 4, so that the bridge 14 and the parallel link 4 are tilted. An inclination adjustment link 7 is provided on the other end side of the bridge 14 so that the inclination angle with respect to the horizontal direction is kept constant when the bridge 14 is moved. The tip step 2 is limited by a flexible member 81 connected to the link 7, but the upward inclination is not limited.

Note that FIGS. 3 to 7 are schematic diagrams for explaining the general configuration of the fall prevention mechanism 1 according to Embodiment 1 of the present invention, and do not strictly represent the detailed structure of each part or the mutual dimensional relationship. do not have.

The tip step 2 is formed in a flat plate shape and is attached to the front end of the bridge 14, and when there is a height difference between the tip of the bridge 14 and the landing target of the offshore facility, the tip step 2 is formed in a flat plate shape and is attached to the front end of the bridge 14. This is a structure that allows workers to move easily to the landing target.

The tip end step 2 has an end on the side of the bridge 14 (i.e., a rear end) that is axially supported via a bridge front end rotation shaft 3 arranged along the left-right direction and rotates with respect to the front end of the bridge 14. possible to be connected. As a result, the tip step 2 is able to tilt upwardly and downwardly with respect to the plate surface of the bridge 14 with the bridge front end rotating shaft 3 as the center of rotation, that is, has a degree of freedom in vertically tilting the bridge 14. Attached to The size of the tip step 2 is not limited to a specific size, and is appropriately set to an appropriate size by taking into consideration, for example, the structure of the bridge 14 or the landing target of the offshore facility. The front-back dimension of the tip step 2 may be set to, for example, about 40 to 70 cm, just as an example.

In order to prevent damage when the tip step 2 and the landing target of the offshore facility come into contact, a resin front cushion 21 is attached to the front end surface of the tip step 2, and a resin cushion 21 is attached to the front edge of the lower surface. A lower cushion 22 is attached.

The parallel link 4 is a link that is provided so that the longitudinal direction/axial direction L ₄ is parallel to the longitudinal direction L ₁₄ of the bridge 14 and swings upward and downward with respect to the main table 12. In combination with the table 12, a set of parallel links is constructed. The parallel link 4 is configured such that one end thereof is rotatable via a parallel link connection mechanism 5 provided on the main table 12, and is provided so as to be swingable upward and downward relative to the main table 12. In the example shown in the figure, the parallel link 4 is arranged near the left side of the bridge 14.

The parallel link connection mechanism 5 includes a link connection column 51 that stands perpendicularly to the top surface of the main table 12 , a connection slider 52 that is provided on the front side of the link connection column 51 , and a connection slider 52 that is provided on the top surface of the main table 12 . It has a guide rail 53 that is fixedly attached and supports the link connecting column 51.

The connection slider 52 is provided so as to be slidable on the front surface of the link connection column 51, is movable along the longitudinal direction (that is, the vertical direction) of the link connection column 51, and can be fixed at any position. It is composed of Further, the link slider 52 is provided with a link rear end rotating shaft 6 arranged along the left-right direction.

The guide rail 53 is arranged along the longitudinal direction/axial direction L ₄ of the parallel link 4 and the longitudinal direction L ₁₄ of the bridge 14 (that is, along the front-rear direction), and is fixed to the upper surface of the main table 12. and installed. Furthermore, the link connecting column 51 is provided such that the lower part of the link connecting column 51 is slidable relative to the upper surface of the guide rail 53, and is movable along the longitudinal direction (i.e., the front-back direction) of the guide rail 53. It is configured so that it can be fixed in any position.

The end of the parallel link 4 on the main table 12 side (i.e., the rear end) is axially supported via the link rear end rotation shaft 6 and is rotatably connected to the parallel link connection mechanism 5. Therefore, the parallel link 4 is configured to be able to swing freely relative to the main table 12 with the link rear end rotating shaft 6 as the center of rotation. In the example shown in the figure, the link rear end rotation shaft 6 is provided above the bridge rear end rotation shaft 16 .

The distal end step 2 has a degree of freedom of vertical inclination, and is configured to be able to freely incline upward and downward, while the angle of downward inclination is limited to a predetermined angle. As a mechanism for limiting the downward inclination angle of the tip step 2, an inclination adjustment link 7 and an inclination limiter 8 are provided.

The inclination adjustment link 7 is rotatably connected to the bridge front end rotating shaft 3, so that the inclination adjustment link 7 is rotatably provided with respect to the bridge 14, and the inclination adjustment link 7 and the tip step 2 are They are configured to be mutually rotatable.

Further, the end of the parallel link 4 on the tip step 2 side (i.e., the front end) is connected to the bridge front end rotation shaft 3 via the link front end rotation shaft 9 arranged along the left-right direction. In the upper position, they are mutually rotatably connected to the inclination adjustment link 7.

Here, the length from the rotation axis of the bridge rear end rotation shaft 16 of the bridge 14 to the rotation axis of the bridge front end rotation shaft 3, and the length from the rotation axis of the link rear end rotation shaft 6 of the parallel link 4 to the link front end rotation axis. The length to the rotation axis of 9 is set to the same dimension. Note that since the longitudinal direction/axial direction L ₄ of the parallel link 4 and the longitudinal direction L ₁₄ of the bridge 14 are provided so as to be parallel to each other, the link rear end rotates from the rotation axis of the bridge rear end rotation shaft 16. The distance to the rotation axis of the shaft 6 in side view and the distance from the rotation axis of bridge front end rotation shaft 3 to the rotation axis of link front end rotation shaft 9 in side view are the same dimension. In other words, the bridge rear end rotation axis 16, the link rear end rotation axis 6, the bridge front end rotation axis 3, and the link front end rotation axis 9 function as each node (rotation axis) of the four-section parallel link, and are therefore parallel to the bridge 14. The link 4 operates in a tilting manner while remaining parallel to each other.

The angle θ ₁ formed by the horizontal direction H and the longitudinal direction of the inclination adjustment link 7 is called an “initial angle”. The initial angle θ ₁ is not limited to a specific value, and is set to about 40° to 120°, for example. In the examples shown in FIGS. 1 to 5, the initial angle θ ₁ is set to an upward slope of 70° with respect to the horizontal direction H.

The connecting slider 52 of the parallel link connecting mechanism 5 is configured so that the longitudinal direction L 4 of the parallel link ₄ becomes parallel to the longitudinal direction L ₁₄ of the bridge 14 when the front end of the parallel link 4 is connected to the inclination adjustment link 7. , the connecting position of the rear end portion of the parallel link 4 is adjusted along the longitudinal direction of the link connecting column 51. Then, in a state where the longitudinal direction L ₄ of the parallel link 4 and the longitudinal direction L ₁₄ of the bridge 14 are parallel to each other, the angle formed by the horizontal direction H and the longitudinal direction of the inclination adjustment link 7 becomes an initial angle θ ₁ . Become.

The inclination limiter 8 is a mechanism for limiting the downward inclination angle of the tip step 2 with respect to the inclination adjustment link 7 (and, by extension, with respect to the horizontal direction) to a predetermined angle. The inclination limiter 8 includes a flexible member 81 and a damper 82. The damper 82 is fixedly attached to the left side surface of the tip step 2 via a fitting.

The flexible member 81 is a member that is interposed between the inclination adjustment link 7 and the tip step 2 to limit the degree of downward inclination of the tip step 2 with respect to the inclination adjustment link 7. The flexible member 81 is made of a material that is flexible and pliable, has enough strength to support the tip step 2 with a worker on it, and does not expand or contract (or hardly expands or contracts). Specifically, it is formed using, for example, a wire rope.

One end of the flexible member 81 is connected to a position near the upper end of the inclination adjustment link 7, and the other end is connected to a damper 82. This limits the angle of downward inclination of the tip step 2 with respect to the inclination adjustment link 7 when the flexible member 81 is stretched.

The angle θ ₂ formed by the horizontal direction H and the longitudinal direction of the tip step 2 is referred to as the “downward angle”. The descending angle θ ₂ is not limited to a specific value, and is set, for example, to about 0° to 40°. In the examples shown in FIGS. 1 to 5, the descending angle θ ₂ is set to a downward slope of 20° with respect to the horizontal direction H.

The fall prevention mechanism 1 may be provided with a mechanism that operates depending on the grounding status of the tip step 2 and informs the worker whether or not the tip step 2 is touching the landing target of the offshore facility. In this embodiment, a strain gauge or a pressure sensor is provided on the lower surface cushion 22 attached to the front edge of the lower surface of the tip step 2, and is operated in response to a signal output from the gauge/sensor. A light 20 is installed near the front end of the bridge handrail 15. Based on the detection result by the gauge/sensor, when the tip step 2 is not touching the landing target of the offshore facility, the light 20 lights up in red (or turns off), and the tip step 2 is connected to the landing target of the offshore facility. The light 20 is configured to light up in blue when the device is grounded. Note that instead of providing the light 20, or in addition to providing the light 20, a speaker that operates according to the grounding situation of the tip step 2 may be provided to indicate whether or not the tip step 2 is touching the landing target of the offshore facility. A notification sound may be emitted.

Next, the operation of the fall prevention mechanism 1 according to the first embodiment having the above configuration will be explained.

When the longitudinal direction L ₁₄ of the bridge 14 is along the horizontal direction H, the inclination adjustment link 7 is in the attitude of the initial angle θ ₁ , and the tip step 2 is in the attitude of the descending angle θ ₂ (Fig. 3).

When the bridge 14 tilts upward around the bridge rear end rotating shaft 16, the tilt adjustment link 7 connected to the front end of the bridge 14 moves upward, and the parallel link connected to the tilt adjustment link 7 moves upward. The link 4 also tilts upward (FIG. 4). Further, when the bridge 14 tilts downward about the bridge rear end rotating shaft 16, the tilt adjustment link 7 connected to the front end of the bridge 14 moves downward, and the tilt adjustment link 7 connected to the bridge rear end rotation shaft 16 moves downward. The parallel link 4 also tilts downward (FIG. 5).

At this time, the bridge rear end rotation shaft 16, the link rear end rotation shaft 6, the bridge front end rotation shaft 3, and the link front end rotation shaft 9 function as each node (rotation shaft) of the four-section parallel link, and the bridge 14 and the parallel link 4 remains parallel to each other, and with this configuration, no matter what angle of inclination the bridge 14 has, the degree of inclination of the inclination adjustment link 7 does not change and the attitude of the initial angle θ ₁ is maintained. (Figures 4 and 5).

By maintaining the attitude of the initial angle θ ₁ with respect to the inclination adjustment link 7, the attitude of the lowering angle θ ₂ with respect to the tip step 2 in the state where the flexible member 81 is stretched is maintained. Therefore, no matter what the inclination angle of the bridge 14 is, the degree of inclination of the tip step 2 does not change, and the footing of the worker who wants to move from the bridge 14 to the landing target of the offshore facility is stabilized.

Here, if the bridge handrail 15 has a shape in which the horizontal frame at the upper end and the vertical frame at the front end intersect and has a right-angled part at the upper part of the front side, when the bridge 14 tilts downward, the right-angled part will move forward. Since the right-angled portion protrudes toward the offshore facility, there is a risk that the right-angled portion may hit equipment on the offshore facility and damage the equipment, or that a worker may be caught between the right-angled portion and the equipment on the offshore facility. In contrast, in this embodiment, the bridge handrail 15 has a first inclined frame 15b and a second inclined frame 15c that are inclined downward from the horizontal frame 15a at the upper end, and is formed in a shape that does not have a right angle part. Therefore, when the bridge 14 tilts downward, the upper part of the front side of the bridge handrail 15 does not protrude forward, and the front end of the bridge handrail 15 may hit equipment on the offshore facility and damage the equipment. This prevents a worker from being caught between the front end of the bridge handrail 15 and equipment on the offshore facility side.

When the flexible member 81 is stretched and the tip step 2 is in a posture with a descending angle θ ₂ (FIG. 6(A)), the bridge 14 is tilted downward due to the rocking of the ship due to irregular and sudden waves. If the tip of the bridge 14 comes into contact with the offshore facility (in other words, runs aground) due to the drive device 19 not being able to operate the drive device 19 in time, the tip step 2 will rotate around the front end rotation shaft 3 of the bridge. It tilts upward (FIG. 6(B)). That is, the tip step 2 is rotatable with respect to the bridge 14 about the bridge front end rotating shaft 3, the inclination adjustment link 7 and the tip step 2 are mutually rotatable, and the inclination limiter 8 While the downward inclination angle of the tip step 2 is limited by a predetermined angle (descending angle θ ₂ ) by the flexible member 81 of the tip step 2, the upward inclination of the tip step 2 is not limited. The tip step 2 freely tilts upward while in contact with the landing target equipment T, thereby preventing the tip step 2 and the landing target equipment T from colliding and being damaged. In addition, in the state shown in FIG. 6(B), the flexible member 81 having flexibility and pliability is simply in a loosened and bent state, and when the tip step 2 moves upwardly, It's not a hindrance.

Note that when the distance in the vertical direction between the tip of the bridge 14 and the landing target equipment T of the offshore facility increases from the state where the tip step 2 tilts upward, the tip step 2 freely tilts downward. , the flexible member 81 is stretched and stops in a position where the downward inclination angle becomes a predetermined angle (descending angle θ ₂ ). At this time, due to the action of the damper 82 to which the flexible member 81 is connected, the impact when the tip step 2 tilts downward and is stopped at a predetermined angle (descending angle θ ₂ ) is absorbed and alleviated. be done.

Here, the descending angle θ ₂ of the tip step 2 is adjusted by the action of the parallel link connection mechanism 5. Specifically, for example, if you want to make the degree of inclination of the tip step 2 smaller than the descending angle θ ₂ from the descending angle θ ₂ , move the link connecting column 51 backward along the longitudinal direction of the guide rail 53. On the other hand, if it is desired to make the lowering angle larger than θ ₂ , the link connecting column 51 is moved forward along the longitudinal direction of the guide rail 53. Specifically, for example, as shown in FIG. 7A, the initial angle θ ₁ of the inclination adjustment link 7 is an upward inclination (elevation angle) of 70°, and the descending angle θ ₂ of the tip step 2 is a downward inclination (depression angle) of 20°. As shown in FIG. 7(B), when the link connecting column 51 is moved backward by a retreating distance Dx from the state where the link connecting column 51 is is moved backwards by the same distance Dx, which causes a tilting of the tilt adjustment link 7 (initial angle θ ₁ =90°) and adjusts the degree of tilt of the tip step 2 via the flexible member 81. changes (descending angle θ ₂ =0°). At this time, the connection position of the rear end of the parallel link 4 is adjusted by the connection slider 52 of the parallel link connection mechanism 5 so that the longitudinal direction L ₄ of the parallel link 4 is parallel to the longitudinal direction L ₁₄ of the bridge 14. It is adjusted along the longitudinal direction of the pillar 51.

According to the fall prevention mechanism 1 according to the first embodiment, when the tip of the bridge 14 moves upward with respect to the landing target due to the influence of waves, the inclination limiter 8 (particularly the flexible member 81 ) prevents the tip step 2 provided at the tip of the bridge 14 from tilting downward more than a predetermined inclination angle (descent angle θ ₂ ). This prevents a worker who is putting his or her feet on the bridge from losing his balance or slipping off his foot and falling from the tip of the bridge 14, which in turn makes it possible to improve safety. In addition, if the tip of the bridge 14 moves downward with respect to the landing target due to the influence of waves, the tip step 2 provided at the tip of the bridge 14 is not limited to upward inclination, and the tip step 2 is tilted upward. This prevents the upward inclination angle of the tip step 2 from changing freely in response to the contact between the tip step 2 and the landing target equipment T, thereby preventing a collision situation. , it becomes possible to prevent damage to the landing target equipment T and the tip step 2.

(Embodiment 2)
8 to 13 are diagrams showing a fall prevention mechanism 1 according to a second embodiment of the invention. This second embodiment differs in configuration from the first embodiment described above mainly in that an upward tilt assisting mechanism 30 is provided at the tip step 2 of the fall prevention mechanism 1. In the description of this second embodiment, the same components as those of the first embodiment described above are given the same reference numerals, and the description thereof will be omitted. In the description of this second embodiment, the operation in which the tip step 2 rotates upward and tilts with respect to the plate surface of the bridge 14 about the bridge front end rotation axis 3 is expressed as "tilting". .

Note that FIGS. 11 to 13 are schematic diagrams for explaining the general configuration of the fall prevention mechanism 1 according to Embodiment 2 of the present invention, and do not strictly represent the detailed structure of each part or the mutual dimensional relationship. do not have.

Regarding the fall prevention mechanism 1 according to the first embodiment described above, for example, due to the performance limit of the control device (not shown) and the drive device 19, , a situation is also considered in which the front end of the tip step 2 (specifically, the front cushion 21 in the example shown in the figure) attached to the front end of the bridge 14 contacts/collides with the landing target equipment T of the offshore facility in the front and back direction. It will be done. At this time, the tip step 2 is rotatable with respect to the bridge 14 about the bridge front end rotating shaft 3 as a center of rotation, and the angle of downward inclination is adjusted to a predetermined angle (i.e., by the flexible member 81 of the inclination limiter 8 , downward angle θ ₂ ), while upward inclination is not limited. For this reason, while the tip step 2 can tilt upward from the posture where the flexible member 81 is stretched and the downward angle θ ₂ is downward, it is not possible to tilt the tip further downward (see FIG. 11). ).

Here, the longitudinal direction _L14 of the bridge 14 is along the horizontal direction H, the inclination adjustment link 7 is in the attitude of the initial angle θ ₁ , and the tip step 2 is in the attitude of the descending angle θ ₂ . (See FIG. 11), in the direction D _T along the surface Ts with which the tip step 2 (in particular, the front cushion 21) of the landing target equipment T may come into contact/collision in the front-rear direction, the front cushion 21 is A position 21 _T where the front cushion 21 contacts the surface Ts is located below the axial center position of the bridge front end rotation shaft 3, that is, a position 21 _T where the front cushion 21 contacts the surface Ts is the axis of the bridge front end rotation shaft 3. It is located below position 3 _T of the perpendicular line drawn from the center to the plane Ts. As a result, when the tip step 2 contacts/collides with the landing target equipment T, the force F generated in the tip step 2 acts in a direction passing below the bridge front end rotating shaft 3. Therefore, a force is applied to the tip step 2 to push it downward, and a force is applied to the tip step 2 to cause it to tilt further downward than the descending angle θ ₂ . Landing target equipment T may be damaged.

Therefore, the fall prevention mechanism 1 according to this embodiment has a bridge 14 supported at one end, and is provided on the other end side of the bridge 14 so as to be able to tilt upwardly and downwardly, and has an angle of downward tilt with respect to the horizontal direction. a tip step 2 whose upward inclination is not limited, a tilting control member 31 that is fixedly attached to the tip step 2 and tilts upward with respect to the horizontal direction; It has a front wheel 33 as a moving member attached to the end portion on the side opposite to the bridge 14.

The upward tilt assisting mechanism 30 is a mechanism for tilting the tip step 2 upward when the tip step 2 attached to the front end of the bridge 14 contacts/collides with the landing target equipment T in the front-rear direction. , mainly includes a tilt control member 31, a buffer sliding member 32, a front wheel 33, and a rear wheel 34.

The tilt control member 31 is fixedly attached to the front end of the end face of the tip step 2 in the left-right direction. Although the upward tilt assist mechanism 30 including the tilt control member 31 is provided on the left end surface of the tip step 2 in the illustrated example, it may be provided on the right end surface of the tip step 2. Alternatively, they may be provided as a pair of left and right end surfaces on the left end surface and the right end surface of the tip step 2. By providing the upward tilt assist mechanism 30 including the tilt control member 31 as a pair of left and right end faces on the left and right end faces, the tip step 2 is tilted (in other words, distorted). This is preferable in that it can prevent.

The tilt control member 31 has a portion closer to the end on the tip step 2 side (that is, a portion closer to the rear end; in other words, a portion closer to the lower end) fixedly relative to the front end of the left end surface of the tip step 2. It is attached.

Damage caused when the tilting control member 31 and the landing target equipment T come into contact with the surface of the tilting control member 31 opposite to the tip step 2 (i.e., the front surface; in other words, the lower surface) In order to prevent this, a buffer sliding member 32 is attached. The buffer sliding member 32 is not limited to a specific member or structure, and can function as a cushioning material when it comes into contact with the landing target equipment T, and can slide with respect to the landing target equipment T. It may be any member or structure. In the example shown in the figure, a hollow rubber cushioning material having a D-shaped cross section orthogonal to the longitudinal direction is attached as the buffer sliding member 32 (note that the curved portion of the D-shape is on the opposite side of the tip step 2 (i.e., (front side; in other words, the bottom side).

A front wheel 33 is provided at an end portion of the tilt control member 31 opposite to the tip step 2 (that is, a front end portion; in other words, an upper end portion) so as to protrude further forward and downward than the buffer sliding member 32. be fixed and attached to. In connection with the attachment of the front wheels 33, the buffer sliding member 32 is attached to the front surface (in other words, the lower surface) of the tilt control member 31, except for the portion to which the front wheels 33 are attached. In order to reduce the impact when the front wheels 33 and the landing target equipment T contact/collide, a buffer member such as a rubber sheet is provided between the front wheels 33 and the tilt control member 31. The front wheels 33 may be attached to the tilt control member 31 at the top.

The front wheels 33 may be wheels that cannot be rotated horizontally and are rotatable only in the front-rear direction, or may be casters that are horizontally rotatable and rotatable in all directions. In the example shown in the figure, a wheel is attached as the front wheel 33 to the front end portion (in other words, the upper end portion) of the tilt control member 31, and is not horizontally rotatable but rotatable only in the front-rear direction.

Note that the mechanism attached to the front end portion (in other words, the upper end portion) of the tilt control member 31 is not limited to wheels, and can be moved by running or sliding on the surface Ts of the landing target equipment T. Any mechanism is fine as long as it is something like that. The mechanism (wheels in the illustrated example) attached to the front end/upper end portion of the tilt control member 31 is also referred to as a "front moving member."

A rear wheel 34 is attached to the front end portion of the lower surface of the tip step 2. The rear wheel 34 is attached in place of the resin lower cushion 22 attached to the front edge of the lower surface in the first embodiment described above.

The rear wheels 34 may be wheels that cannot be rotated horizontally and are rotatable only in the front-rear direction, or may be casters that are horizontally rotatable and rotatable in all directions. In the example shown in the figure, a pair of left and right wheels that cannot be rotated horizontally but are rotatable only in the front-rear direction are attached to the front end portion of the lower surface of the tip step 2 as the rear wheels 34.

The rear wheel 34 is attached to the lower surface of the tip step 2 and is provided so as to protrude slightly from the buffer sliding member 32. Regarding the rear wheels 34, for example, the buffer sliding member 32 comes into contact with the corner Tc of the landing target equipment T and moves along the longitudinal direction of the buffer sliding member 32 (that is, the longitudinal direction of the tilt control member 31). When the rear wheel 34 reaches the corner Tc by sliding Tc, if the amount of protrusion from the buffer sliding member 32 is large, the rear wheel 34 hits and gets caught on the corner Tc. It is possible. Therefore, the rear wheel 34 receives an impact when the shock absorbing sliding member 32 is sliding on the corner Tc, and when the rear wheel 34 comes into contact with the corner Tc and overcomes the corner Tc. In order to prevent it from becoming excessive or getting caught on the corner Tc, it is attached to the lower surface of the tip step 2 and is provided so as to protrude slightly beyond the buffer sliding member 32.

Note that the lower surface cushion 22 may be attached to the front end portion of the lower surface of the tip step 2 instead of the rear wheel 34 as in the first embodiment described above. Furthermore, the mechanism attached to the front end portion of the lower surface of the tip step 2 may be any mechanism as long as it can move by running or sliding on the surface Ts of the landing target equipment T. The mechanism (wheels in the illustrated example) attached to the front end portion of the lower surface of the tip step 2 is also referred to as a "rear side moving member."

The longitudinal direction _L14 of the bridge 14 is along the horizontal direction H, the inclination adjustment link 7 is in the initial angle θ ₁ attitude, and the tip step 2 is in the descending angle θ ₂ attitude, and the horizontal It is provided so as to be inclined with respect to the direction H at a predetermined upwardly inclined angle. The angle θ ₃ formed by the horizontal direction H and the longitudinal direction of the tilt control member 31 is referred to as the "upward tilt angle." The upward inclination angle θ ₃ is not limited to a specific value, and is set, for example, to about 20° to 50°. In the example shown in the figure, the upward inclination angle θ ₃ is set to an upward inclination of 35° with respect to the horizontal direction H.

Here, regarding the mutual positional relationship between the bridge front end rotating shaft 3 that rotatably supports the tip step 2 and the rotating shaft 331 of the front wheel 33, the longitudinal direction _L14 of the bridge 14 is along the horizontal direction H and is inclined. When the adjustment link 7 is in the attitude of the initial angle θ ₁ , the tip step 2 is in the attitude of the descending angle θ ₂ , and the tilting control member 31 is in the attitude of the upward inclination angle θ ₃ (Fig. 12), in the direction D T along the surface _Ts with which the upward tilting assistance mechanism 30 (in particular, the front wheels 33) of the landing target equipment T may come into contact/collide in the longitudinal direction, the front wheels 33 are In other words, the perpendicular line drawn from the axis of the rotation shaft 331 of the front wheel 33 to the surface Ts is arranged so that the position 33 _T that contacts the surface Ts is located above the axial center position of the bridge front end rotation shaft 3. The foot position _33T is adjusted so that it is located above the foot position _3T of the perpendicular line drawn from the axis of the bridge front end rotating shaft 3 to the plane Ts. As a result, when the upward tilting assist mechanism 30 contacts/collides with the landing target equipment T, the force F generated on the tip step 2 via the upward tilting assist mechanism 30 is directed in the direction passing above the bridge front end rotating shaft 3. work. Therefore, a force is exerted on the tip step 2 via the upward tilting assisting mechanism 30, and the upward tilting assisting mechanism 30 and the tip step 2 tilt upward with the bridge front end rotating shaft 3 as the center of rotation. .

Also, regarding the mutual positional relationship between the bridge front end rotating shaft 3 that rotatably supports the tip step 2 and the rotating shaft 341 of the rear wheel 34, while the front wheel 33 is running on the surface Ts of the landing target equipment T, The upward tilt assisting mechanism 30 and the tip step 2 tilt upward about the bridge front end rotating shaft 3, so that the longitudinal direction of the tilting control member 31 and the longitudinal direction of the buffer sliding member 32 are aligned in the direction D along the plane Ts. _T is the position 34 where the rear wheel 34 contacts the surface Ts in the direction D _T along the surface Ts (see FIG. 13), and _T is the axial center position of the bridge front end rotating shaft 3. In other words, the foot position 34 _T of the perpendicular line drawn from the axis of the rotating shaft 341 of the rear wheel 34 to the plane Ts is located above the axis of the bridge front end rotating shaft 3. The foot is adjusted so that it is above position 3 _T of the perpendicular line drawn down. As a result, the tip step 2 is further pushed into the landing target equipment T from a state in which the longitudinal direction of the tilt control member 31 and the longitudinal direction of the buffer sliding member 32 are parallel to the direction D _T along the plane Ts. At this time, the force F generated on the tip step 2 via the upward tilt assisting mechanism 30 acts in a direction passing above the bridge front end rotating shaft 3. Therefore, a force is exerted on the tip step 2 via the upward tilting assisting mechanism 30, and the upward tilting assisting mechanism 30 and the tip step 2 tilt upward with the bridge front end rotating shaft 3 as the center of rotation. .

Note that the longitudinal direction L ₁₄ of the bridge 14 is along the horizontal direction H, the inclination adjustment link 7 is in the initial angle θ ₁ attitude, the tip step 2 is in the attitude of the descending angle θ ₂ , and the tilt control member is in the attitude 31 is in an upward tilt angle θ ₃ (see FIG. 12), the front wheels 33 are arranged so that they protrude further forward than the front end of the tilt control member 31, and the front end of the buffer sliding member 32 is The dimensions, mounting position, etc. of the front wheel 33 are adjusted so that the front wheel 33 protrudes further forward than the front wheel 33.

Next, the operation of the fall prevention mechanism 1 according to the second embodiment having the above configuration will be explained.

When the longitudinal direction L ₁₄ of the bridge 14 is along the horizontal direction H, the inclination adjustment link 7 is in the attitude of the initial angle θ ₁ , the tip step 2 is in the attitude of the descending angle θ ₂ , and the tilting control is performed. The member 31 is in an upward tilt angle θ ₃ (FIG. 12).

When the bridge 14 tilts upward or downward, the operations and effects of each part related to the tilting motion of the bridge 14 (specifically, mainly the parallel link 4, the tilt adjustment link 7, and the flexible member 8) are as follows. , which is similar to the first embodiment described above.

When the tip of the bridge 14 contacts (in other words, runs over) the landing target equipment T, the tip step 2 rotates around the bridge front end rotating shaft 3 with the rear wheels 34 in contact with the landing target equipment T. As a result, the tip step 2 and the landing target equipment T are prevented from colliding and being damaged by freely tilting upward.

When the distance in the vertical direction between the tip of the bridge 14 and the landing target equipment T increases from the state in which the tip step 2 is tilted upward, the tip step 2 freely tilts downward, and the flexible member 81 is stretched and the downward inclination angle becomes a predetermined angle (that is, the descending angle θ ₂ ), and the robot stops in a posture.

Further, when the flexible member 81 is stretched and the downward tilt angle of the tip step 2 is at a predetermined angle (descending angle θ ₂ ), the upward tilt assisting mechanism 30 and the tip step 2 move toward the landing target equipment T. In the case of contact (in other words, collision) in the front-back direction, the front wheels 33 run on the surface Ts of the landing target equipment T. At this time, in the direction D _T along the surface Ts that the front wheels 33 of the landing target equipment T are in contact with, the position 33 _T where the front wheels 33 contact the surface Ts is the axis of the bridge front end rotating shaft 3. In other words, the foot position 33 _T of the perpendicular line drawn from the axis of the rotating shaft 331 of the front wheel 33 to the plane Ts is located above the axis of the front end rotating shaft 3 of the bridge. The foot position 3 of the perpendicular line lowered to Ts is adjusted so that it is located above _T , so the force F generated on the tip step 2 via the upward tilting assist mechanism 30 is caused by the force F generated on the front end rotation axis 3 of the bridge. Since it acts in the direction passing upward, a force is applied to the tip step 2 through the upward tilting assisting mechanism 30 to push them upward, and the upward tilting assisting mechanism 30 and the tip step 2 rotate around the bridge front end rotating shaft 3. Tilts upward.

According to the fall prevention mechanism 1 according to the second embodiment, the following effects are achieved in addition to the effects provided by the fall prevention mechanism 1 according to the first embodiment described above. That is, when the tip of the bridge 14 comes into contact with/collides with the landing target equipment T in the front-back direction due to the influence of waves, etc., the upward tilt assist mechanism 30 (in particular, the tilt control member 31) works to prevent the bridge 14 from moving. By tilting the tip step 2 upward together with the tilting control member 31 provided at the tip, it is possible to prevent a force from being applied to the tip step 2 to cause the tip step 2 to tilt further downward than the descending angle θ ₂ . Therefore, it is possible to prevent damage to the tip step 2 and the landing target equipment T.

Although the embodiments of this invention have been described above, the specific configuration is not limited to the above embodiments, and even if there are changes in the design within the scope of the gist of this invention, Included in invention. For example, in the embodiment described above, the bridging device 10 equipped with the fall prevention mechanism 1 has the sway correction mechanism 11, but the bridging device 10 may have a configuration that does not include the sway correction mechanism 11. In this case as well, the fall prevention mechanism 1 according to the present invention limits the downward inclination angle of the tip step 2 to a predetermined angle in relation to the tilting operation of the bridge 14 caused by the operation of the swing operation mechanism 17. The effect of preventing a collision situation by freely changing the angle of the upward inclination of No. 2 is achieved. Furthermore, in the second embodiment described above, the upward tilting assistance mechanism 30 is installed on the tip step 2 attached to the bridge 14 constituting the bridge construction device 10; however, the upward tilting assistance mechanism 30 is installed. The target is not limited to the tip step 2 attached to the bridge 14 constituting the bridge device 10. The upward tilt assisting mechanism 30 is applicable to the tip step 2 configured such that the upward tilt is not restricted while the downward tilt angle is restricted to a predetermined angle, and constitutes the bridging device 10. It is not an essential configuration that the tip step 2 is attached to the bridge 14.

Further, in the embodiment described above, the fall prevention mechanism 1 is installed on the bridge device 10 installed on a ship to bridge the bridge 14 from the ship to the landing target of the offshore facility. A fall prevention mechanism may be provided for a bridge device that is installed in a ship and connects a bridge from an offshore facility to a ship.

Further, in the above embodiment, the inclination adjustment link 7 is connected and supported by the bridge front end rotating shaft 3, and the tip step 2 is also connected and supported by the bridge front end rotating shaft 3. The front end of the bridge 14 may be connected and supported by another shaft.

Further, in the above embodiment, the tip step 2 is formed using a single plate-like member and has a fixed length, but the tip step 2 is formed using a plurality of plate-like members. It may be configured to be extendable and retractable. In this case, for example, a recess is formed on the upper surface of the landing target equipment T of the offshore facility to the extent that the lower surface cushion 22 or the rear wheel 34 of the tip step 2 fits therein. Even if the lower cushion 22 or the rear wheels 34 fit into the recess on the landing target equipment T side, and the longitudinal distance between the tip of the bridge 14 and the landing target of the offshore facility changes somewhat due to the influence of waves, By expanding and contracting the tip step 2, the tip step 2 is prevented from falling off from the landing target. In addition, in order to prevent damage to the tip step 2, if the tip of the bridge 14 moves further away from the landing target with the tip step 2 extended to its maximum dimension, the bottom cushion 22 or the rear side of the tip step 2 will be damaged. It is preferable that the fit between the lower surface cushion 22 or the rear wheel 34 and the recess is adjusted to such an extent that the wheel 34 is removed from the recess on the landing target equipment T side.

Further, in the above embodiment, the rear end of the parallel link 4 is configured to be movable in the front-rear direction by the parallel link coupling mechanism 5, but the position of the rear end of the parallel link 4 is fixed. may be configured. In this case, although it is not possible to adjust the degree of inclination (initial angle θ ₁ ) of the inclination adjustment link 7 to adjust the degree of inclination (descending angle θ ₂ ) of the tip step 2, for example, The degree of inclination (descending angle θ ₂ ) of the tip step 2 may be adjusted by changing the length.

Furthermore, in the embodiment described above, the angle of the downward inclination of the distal step 2 is limited to a predetermined angle (descending angle θ ₂ ) by the flexible member 81; however, the downward inclination of the distal step 2 is The mechanism for limiting the degree of distal step 2 while not limiting the upward inclination of distal step 2 is not limited to flexible member 81. For example, a claw portion may be provided that extends forward from the lower end of the inclination adjustment link 7, and the lower surface of the tip step 2 may be supported by the claw portion. In this case as well, the lower surface of the tip step 2 comes into contact with the claw part, so that the angle of downward inclination of the tip step 2 is limited to a predetermined angle, while the claw part that supports the lower surface of the tip step 2 makes the tip Since the upward inclination of the step 2 is not restricted, the tip step 2 freely tilts upward with the lower cushion 22 in contact with the landing target equipment T of the offshore facility, causing the tip step 2 and the landing target equipment T to collide. This prevents damage. That is, the downward inclination angle of the tip step 2 may be limited by a member (for example, the flexible member 81) that connects with the inclination adjustment link 7, or a portion that connects with the inclination adjustment link 7 (for example, It may also be limited by a claw part).

1 Fall prevention mechanism 2 Tip step 21 Front cushion 21 Position where _{the T} front cushion contacts the surface of the landing target equipment 22 Lower cushion 3 Bridge front end rotation shaft 3 From the axis of _{the T} bridge front end rotation shaft to the surface of the landing target equipment Position of the lowered perpendicular foot 4 Parallel link 5 Parallel link connection mechanism 51 Link connection column 52 Connection slider 53 Guide rail 6 Link rear end rotation axis 7 Inclination adjustment link 8 Inclination limiter 81 Flexible member 82 Damper 9 Link front end rotation Axis 10 Bridge device 11 Sway correction mechanism 111 Base frame 112 Actuator 12 Main table 121 Auxiliary table 13 Table handrail 14 Bridge 15 Bridge handrail 15a Horizontal frame 15b First inclined frame 15c Second inclined frame 16 Bridge rear end rotating shaft 17 Swing operation Mechanism 18 Operation arm 18a Bent part 18b First arm 18c Second arm 19 Drive device 19a Cylinder tube 19b Piston rod 20 Light 30 Upward tilt assist mechanism 31 Tilt control member 32 Buffer sliding member 33 Front wheel 331 Rotating shaft 33 _T front wheel 34 Rear wheels 341 Rotating shaft 34 _T Position where the rear wheels contact the surface of the landing target equipment T Landing target equipment Ts Surface of the landing target equipment (front wheels contact/ surfaces that may collide)
Tc Corner of landing target equipment D Direction along the surface of _T landing target equipment L ₄ Longitudinal direction/axial direction of parallel link L ₁₄ Longitudinal direction of bridge H Horizontal direction θ ₁ Initial angle (horizontal direction and longitudinal direction of inclination adjustment link direction)
θ ₂ Descent angle (angle between the horizontal direction and the longitudinal direction of the tip step)
θ _3Upward tilt angle (angle between the horizontal direction and the longitudinal direction of the tilt control member)
F Force generated at the tip step

Claims (7)

A fall prevention mechanism provided for a bridge construction device having a table and a bridge whose one end on the table side is supported by a shaft and tilts upward and downward with respect to the table,
a parallel link that is arranged parallel to the longitudinal direction of the bridge, one end on the table side is supported by a shaft, and tilts upward and downward while remaining parallel to the longitudinal direction of the bridge;
It is rotatably connected to the other end of the bridge and rotatably connected to the other end of the parallel link, so that when the bridge and the parallel link tilt, the angle of inclination with respect to the horizontal direction is kept constant. tilt adjustment link,
The bridge is provided on the other end side of the bridge so as to be able to tilt upwardly and downwardly, and the angle of the downward tilt with respect to the horizontal direction is limited by a member connected to the tilt adjustment link or a portion connected to the tilt adjustment link. and a tip step that changes the angle of upward inclination in response to contact with the target equipment to prevent a collision with the target equipment,
A fall prevention mechanism characterized by: The angle of the downward inclination of the distal step is limited by a flexible member connected to the inclination adjustment link.
The fall prevention mechanism according to claim 1, characterized in that: a mechanism for moving a position at which the one end of the parallel link is axially supported along the longitudinal direction of the parallel link and fixing it at a desired position;
The angle of the downward inclination of the tip step is adjusted by changing the inclination angle of the inclination adjustment link via the parallel link.
The fall prevention mechanism according to claim 1 or 2, characterized in that: The bridge is equipped with a handrail,
The handrail has, on the other end side of the bridge, a sloped frame that connects with a horizontal frame disposed at the upper end and slopes downward.
The fall prevention mechanism according to any one of claims 1 to 3. comprising at least one of a light and a speaker that operates in conjunction with whether or not the tip step is grounded to the target equipment;
The fall prevention mechanism according to any one of claims 1 to 4. a bridge supported at one end;
a tip step provided on the other end of the bridge so as to be able to tilt upwardly and downwardly, the angle of the downward inclination with respect to the horizontal direction being limited, but the upward inclination being not limited;
a tilting control member fixedly attached to the tip step and tilting upward with respect to the horizontal direction;
a moving member attached to a side of the upwardly inclined tip portion of the tilt control member opposite to the bridge;
The tilting control member is configured such that when the bridge approaches and collides with the target equipment, the moving member moves upward on the surface of the target equipment to tilt the tip step upward.
A fall prevention mechanism characterized by: A cushioning material is attached to a side of the tilt control member opposite to the bridge;
7. The fall prevention mechanism according to claim 6.

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