WO2018155027A1

WO2018155027A1 - Lifting and lowering device

Info

Publication number: WO2018155027A1
Application number: PCT/JP2018/001538
Authority: WO
Inventors: 伸一関根; 伸郎片原; 敦士豊内; 武志南澤
Original assignee: Ｋｙｂ株式会社
Priority date: 2017-02-21
Filing date: 2018-01-19
Publication date: 2018-08-30
Also published as: KR20180109923A; JP2018134958A; CN108883786A; TW201832967A

Abstract

Provided is a lifting and lowering device that can be handled with ease. This lifting and lowering device (1) is provided with a frame (10), a crawler (20), a caster unit, and a swivel caster unit (70). The frame (10) has a built-in drive unit. The crawler (20) is provided on both the right and left sides of the frame (10) as a paired unit and is driven by the drive unit. The caster unit is disposed in the vicinity of the central position between the pair of crawlers (20) in a planar view. The caster unit has a wheel. The wheel protrudes downward beyond the under surface of the crawler (20). The swivel caster unit (70) is disposed rearward of the caster unit. The swivel caster unit (70) has a swivel wheel (71). The swivel wheel (71) is provided so as to be movable between a protruded state in which the swivel wheel is situated below the under surface of the crawler (20) and a housed state in which the swivel wheel is situated at the inner side of an outer peripheral surface of the crawler (20) in a side view.

Description

lift device

The present invention relates to a lifting device.

Patent Document 1 discloses a conventional lifting device. The lifting device includes a pair of left and right crawler type endless tracks (hereinafter simply referred to as crawlers) and a vehicle body having a drive source for driving the crawlers. Also, a pair of left and right casters that protrude downward from the crawler are provided at the front and rear of the lifting device.

JP-A-10-129541

In the lifting device of Patent Document 1, the front caster is a free wheel, and the rear caster is a fixed wheel. In this case, at the time of turning (direction change), it turns around the left and right center of the rear caster. That is, the length to the center of the left and right of the rear caster and the length to the front end is required as the turning radius. For this reason, turning in a narrow place is difficult.

The present invention has been made in view of the above-described conventional situation, and an object to be solved is to provide an elevating device that can be easily handled.

The lifting device of the present invention includes a frame, a crawler, a caster unit, and a universal caster unit. The frame incorporates a drive unit. A pair of crawlers is provided on the left and right sides of the frame and is driven by a drive unit. The caster unit is disposed near the center of the pair of crawlers in plan view. The caster unit has wheels. The wheel protrudes below the lower surface of the crawler in a state of traveling on flat ground. The universal caster unit is arranged in front of or behind the caster unit. The universal caster unit has a universal wheel. The universal wheel is provided so as to be movable between a protruding state positioned below the lower surface of the crawler in a state of traveling on a flat ground and a storage state positioned on the inner peripheral surface of the crawler in a side view.

The elevating device of the present invention may include a detection sensor that detects that the free wheel is stored. The drive unit can be permitted to operate when the detection sensor detects the storage state.

It is side surface sectional drawing which shows the raising / lowering apparatus of Embodiment 1. It is a bottom face fragmentary sectional view showing the raising and lowering device of Embodiment 1. FIG. 3 is an enlarged view of a main part of FIG. 2. It is a figure which shows typically the raising / lowering apparatus of Embodiment 1, and shows the state which raises / lowers a staircase. It is side surface sectional drawing which shows the raising / lowering apparatus of Embodiment 1, and shows the state which extended the supporting member. It is a bottom view schematic diagram for demonstrating the caster unit of Embodiment 1. FIG. It is a side view schematic diagram for demonstrating the caster unit of Embodiment 1. FIG. It is a side surface partial enlarged view for demonstrating the universal caster unit of Embodiment 1, and is a figure which shows the protrusion state of a universal wheel. It is a principal part enlarged view for demonstrating the universal caster unit of Embodiment 1, and is a figure which shows the accommodation state of a universal wheel. It is a principal part enlarged view for demonstrating the inclination detection sensor of Embodiment 1. FIG. FIG. 6 is a diagram (No. 1) for describing an operation of the lifting device of the first embodiment. It is FIG. (2) for demonstrating an effect | action of the raising / lowering apparatus of Embodiment 1. FIG.

Embodiment 1 that embodies the lifting device of the present invention will be described with reference to the drawings. In the following description, for the front and rear directions, the traveling direction when moving down the stairs (left side in FIG. 1) is the forward direction when moving up and down (rightward in FIG. 1). ) Is defined as the rear of the lifting device.

<Embodiment 1>
The lifting device 1 according to the first embodiment is a device that lifts and lowers stairs. As shown in FIGS. 1 and 2, the lifting device 1 includes a frame 10, a crawler 20, a loading platform 30, a handle 40, a support member 50, a caster unit 60, and a universal caster unit 70.

As shown in FIGS. 1 to 3, the frame 10 includes a frame body portion 10A, a motor mounting portion 10B, a crawler guide portion 10C, a front bearing portion 10D, and a rear bearing portion 10E. Yes. A drive unit 11 is incorporated in the frame 10.

The frame body portion 10A is formed in a substantially rectangular frame shape in plan view. The motor attachment portion 10B is provided to protrude forward from the front portion of the frame body portion 10A, and a motor 11A of the drive unit 11 described later is attached. A pair of crawler guide portions 10C is provided on the left and right sides of the frame body portion 10A. The crawler guide portion 10C has a groove that opens downward and extends in the front-rear direction. As shown in FIG. 1, the crawler guide portion 10 C has a shape in which the rear end portion is warped up like a warp. The front bearing portion 10D is formed to extend forward from the front end portion of the crawler guide portion 10C, and is provided in each of the pair of crawler guide portions 10C. The front bearing portion 10D supports a drive shaft 11B of the drive unit 11 described later. The rear bearing portion 10E is formed to extend upward from the rear end portion of the crawler guide portion 10C, and is provided in each of the pair of crawler guide portions 10C. The rear bearing portion 10E supports a driven shaft 12A of a driven unit 12 described later.

As shown in FIG. 2, the drive unit 11 has a motor 11A, a drive shaft 11B, and a drive pulley 11C. The motor 11A is a drive source of the crawler 20 and is driven by a battery (not shown). The drive shaft 11B is pivotally supported by the front bearing portion 10D of the frame 10. The drive shaft 11B is rotated by the power of the motor 11A transmitted by a sprocket and a chain. The drive pulley 11C is a toothed pulley around which the crawler 20 is wound.
As shown in FIG. 1, a follower unit 12 is incorporated in the frame 10. The driven unit 12 has a driven shaft 12A and a driven pulley 12B. The driven shaft 12A is pivotally supported by the rear bearing portion 10E of the frame 10. The crawler 20 is wound around the driven pulley 12B.

A pair of crawlers 20 are provided on the left and right sides of the frame 10 and are driven by the drive unit 11. As shown in FIG. 1, the crawler 20 has a substantially triangular ring shape when viewed from the side, and is wound around the drive pulley 11 C, the driven pulley 12 B, and the crawler guide portion 10 C. The crawler 20 is a rubber crawler. The crawler 20 is provided with a plurality of teeth at predetermined intervals on the back surface thereof, and these teeth mesh with the teeth of the drive pulley 11C, and the power of the motor 11A is transmitted and driven. In addition, waved undulations are formed on the surface of the crawler 20 (the surface that contacts the stairs when the stairs are raised and lowered). As shown in FIG. 4, the crawler 20 abuts on the corner of the staircase S at the portion guided by the crawler guide portion 10 C when the staircase S is moved up and down. By operating the drive unit 11 in this state to drive the pair of crawlers 20, the elevating device 1 causes the crawler guide portion 10 C to slide on the back surface of the crawler 20 in contact with the corners of the staircase S. Move S up and down. Each crawler 20 is wound around the crawler guide portion 10 C serving as a contact surface when ascending and descending the stairs S with a length straddling at least two corners of the stairs S.

The load B is placed on the loading platform 30. As shown in FIG. 1, the loading platform 30 has a placement surface portion 31. The mounting surface portion 31 has a lower end portion 31A supported by the frame 10 so as to be rotatable about a rotation axis A1 extending in the left-right direction and orthogonal to the front-rear direction. The placement surface portion 31 is provided to extend obliquely upward and rearward from the lower end portion 31A. As shown in FIG. 2, in the present embodiment, the rotation axis A 1 is disposed near the center of the crawler 20 in the front-rear direction. As shown in FIG. 1, the loading platform 30 has a lower receiving portion 32. The lower receiving portion 32 is provided to extend obliquely upward from the lower end portion 31 A of the placement surface portion 31. The loading platform 30 is formed in a substantially L shape in a side view by the placement surface portion 31 and the lower receiving portion 32. The lower receiving portion 32 receives the lower portion of the load B when the load B is placed on the placement surface portion 31. The lifting device 1 according to the first embodiment is equipped with a polytane tank as the load B. As shown in FIG. 1, a two-stage shelf 33 on which two 20-liter poly tanks can be placed per stage is attached between the placing surface part 31 and the lower receiving part 32. Can hold up to four plastic tanks.

The handle 40 is provided so as to be connected to the upper end portion 31 B of the placement surface portion 31. As shown in FIGS. 1 and 2, a grip portion 41 that is gripped by the operator is provided at the upper end of the handle 40. The handle 40 is gripped by the operator with the grip portion 41, and operations such as changing the traveling direction and changing the tilt angle of the loading platform are performed. The grip 41 has an operation lever 41A. By operating the operation lever 41A, operations such as driving of the drive unit 11, release of a telescopic lock of the support member 50 described later, and unlocking of the protruding state of the free wheel 71 of the universal caster unit 70 are performed.

The support member 50 is disposed between the frame 10 and the loading platform 30 so as to be stretchable. The support member 50 supports the mounting surface portion 31 with respect to the frame 10 at a desired inclination angle. In the present embodiment, the support member 50 has one end connected to the frame 10 behind the rotation axis A1 and the other end connected to the placement surface 31 between the lower end 31A and the upper end 31B. By extending and contracting between them, the loading platform 30 is supported in a state in which the placement surface portion 31 is inclined at a desired inclination angle with respect to the frame 10. The state shown in FIG. 1 shows a state in which the support member 50 is most contracted. In this state, the placing surface portion 31 is in the most inclined state and the handle 40 is over the rear end of the rear end of the crawler 20. It will be in a hung state. Further, the state shown in FIG. 5 shows a state in which the support member 50 is extended most. In this state, the placing surface portion 31 is in the most upright state, and the entire loading platform 30 and the handle 40 are the crawler 20. It will be in the state located between the front and rear ends.

In this embodiment, the support member 50 employs a gas spring that applies a biasing force in the extending direction. Further, the support member 50 has a free lock mechanism that locks expansion and contraction with a desired length. Since the gas spring having such a free lock mechanism adopts a well-known structure, the gas spring is not illustrated and will be briefly described below.

The support member 50, which is a gas spring, has a cylinder, a piston, and a rod. The cylinder is formed in a bottomed cylindrical shape, and the piston is slidably accommodated in the cylinder. The rod has a base end connected to the piston, a tip protruding from one end on the opening side of the cylinder, and is inserted into the cylinder so as to be reciprocally movable in the central axis direction. Compressed gas and hydraulic oil are enclosed in the cylinder. The space in the cylinder is divided into a region where compressed gas is sealed and two hydraulic oil regions partitioned by a piston. The two hydraulic oil regions communicate with each other through a communication path formed to be openable and closable. Then, the support member 50 opens the communication path so that the hydraulic oil flows between the two hydraulic oil regions, and the urging force is applied in the direction in which the rod protrudes due to the gas pressure of the compressed gas, that is, the extension direction of the support member 50. It can be expanded and contracted while acting. Moreover, by closing the communication path, the hydraulic oil cannot flow and the expansion and contraction is locked. The support member 50 is unlocked by operating the operation lever 41A of the handle 40 to release the expansion / contraction lock.

The caster unit 60 is disposed between the pair of crawlers 20. As shown in FIGS. 6 and 7, the caster unit 60 has

wheels

61A and 61B. The

wheels

61A and 61B are arranged side by side in the front-rear direction. The rotation axis A2 of the

wheels

61A and 61B extends in the left-right direction and is orthogonal to the front-rear direction. The

wheels

61A and 61B are fixed wheels in which the direction of the rotation axis A2 is fixed. In addition, each

wheel

61A, 61B is provided with two or more along with the direction where the rotating shaft A2 is extended. The wheels 61 A and 61 B are provided so as to protrude downward from the lower surfaces of the pair of crawlers 20 in a state of traveling on a flat ground. Specifically, as shown in FIG. 1, the wheels 61 A and 61 B are grounded so that the lower ends of the wheels 61 A and 61 B protrude downward from the lower surfaces of the pair of crawlers 20. Let it float. In addition, as shown in FIG. 1, “the state of traveling on flat ground” in the lifting device 1 means that wheels 61 A and 61 B and a free wheel 71 of a free caster unit 70 to be described later are placed on a flat ground G serving as a traveling surface. In this state, the imaginary line connecting the rotation axes A2 of the

wheels

61A and 61B and the lower end portion of the crawler guide portion 10C of the frame 10 are placed on the flat ground G. It is almost parallel.

In the present embodiment, the

wheels

61A and 61B are arranged such that a wheel 61A located on the upper side of the stairs and a wheel 61B located on the lower side of the stairs are arranged side by side when the stairs are raised and lowered. These

wheels

61A and 61B are provided in two rows side by side, and the caster unit 60 has a total of four

wheels

61A and 61B. The distance between the front and rear wheels 61 A and 61 B is smaller than the length of the lifting device 1 in the front-rear direction. The distance between the

wheels

61A and 61B is set smaller than the distance between the corners of the staircase S. Furthermore, as shown in FIG. 6, in the present embodiment, the caster unit 60 is disposed near the center of the pair of crawlers 20 in plan view. Moreover, the arrangement position of the caster unit 60 is also near the position of the center of gravity in the plan view of the elevating device 1 in an empty state.

Further, as shown in FIGS. 6 and 7, the caster unit 60 has an arm 62. The arm 62 rotatably supports the

wheels

61A and 61B. As shown in FIG. 7, the arm 62 is supported by the frame 10 so as to be rotatable around a rotation axis A3 that is eccentric below the rotation axis A2 of the

wheels

61A and 61B in a state of traveling on flat ground. The rotation axis A3 is disposed between the front and

rear wheels

61A and 61B. Further, on the arm 62, the wheel 61A located on the rear side in the front-rear direction (upper side of the stairs when the stairs are raised and lowered) is raised, and the wheel 61B located on the front side in the front-rear direction (lower side of the stairs when the stairs are raised and lowered) is lowered. A biasing force is applied in the direction. As shown in FIGS. 6 and 7, in the case of this embodiment, the caster unit 60 has a tension spring 63. The tension spring 63 has one end connected to the rear end of the arm 62 and the other end connected to the frame 10. Thereby, the urging | biasing force is made to act in the direction where the rear side edge part of the arm 62 raises.

The universal caster unit 70 is arranged behind the caster unit 60 as shown in FIGS. 1 and 2. The universal caster unit 70 has a universal wheel 71. The free wheel 71 is in a protruding state (see FIG. 8) positioned below the lower surface of the crawler 20 in a state of traveling on a flat ground, and in a storage state (see FIG. 9) positioned inside the outer peripheral surface of the crawler 20 in a side view. It is provided so that it can move freely between. In other words, the protruding state of the free wheel 71 is a state of protruding below the lower surfaces of the pair of crawlers 20 in the lifting device 1 in a state of traveling on flat ground. When in the projecting state, the free wheel 71 is grounded in a state where the pair of crawlers 20 are floated when traveling on flat ground.

As shown in FIGS. 8 and 9, in the present embodiment, the universal caster unit 70 includes a base plate 72, a fixed hook 73, a solenoid actuator 74, together with the above-described universal wheel 71, And a tension spring 75. As shown in FIG. 2, the universal wheels 71 are arranged in a pair in the left-right direction. The base plate 72 is a plate-like member having a substantially rectangular shape in plan view. A pair of universal wheels 71 are supported on the lower surface of the base plate 72. Further, the rear end portion of the base plate 72 is supported by the frame 10 so as to be rotatable around the rotation axis A4. The fixed hook 73 has a substantially U shape with the upper end connected to the lower surface of the base plate 72, and the base plate 72 cannot be rotated by being locked by a locking claw 74 A of the solenoid actuator 74 fixed to the frame 10. Secure to. That is, the base plate 72 can be rotated around the rotation axis A4 in a state where the locking of the fixed hook 73 by the solenoid actuator 74 is released. The tension spring 75 has one end connected to the upper surface of the base plate 72 and the other end connected to the frame 10. The tension spring 75 applies a biasing force in a direction in which the front end side of the base plate 72 rises. That is, in a state in which the locking of the fixed hook 73 is released, the urging force of the tension spring 75 acts and the base plate 72 rotates in the direction in which the front end portion rises.

Switching between the protruding state and the retracted state of the universal wheel 71 is performed as follows. In the state where the universal caster unit 70 travels on a flat ground, as shown in FIG. 8, the fixing hook 73 is fixed by the solenoid actuator 74 so that the base plate 72 cannot rotate. For this reason, the free wheel 71 fixed to the base plate 72 is in a state of protruding downward from the lower surface of the crawler 20, that is, in a protruding state. From this state, as shown in FIG. 9, when the locking of the fixed hook 73 by the solenoid actuator 74 is released, the free wheel 71 is brought into the housed state by the action of the urging force of the tension spring 75. That is, when the locking of the fixed hook 73 by the solenoid actuator 74 is released, the base plate 72 pulled by the tension spring 75 rotates about the rotation axis A4, and accordingly, the free wheel 71 rises and is stored. It becomes a state. Further, for switching from the housed state to the projecting state, the base plate 72 is rotated around the rotation axis A4 by stepping on the foot or the like, and the fixing hook 73 is locked to the locking claw of the solenoid actuator 74.

Further, as shown in FIGS. 1 to 3, the lifting device 1 includes an inclination detection sensor 80 and a storage state detection sensor 90. The inclination detection sensor 80 detects a state in which the placement surface portion 31 of the loading platform 30 has fallen more than a predetermined angle. In the case of this embodiment, the inclination detection sensor 80 detects this when the placing surface portion 31 of the loading platform 30 is in the most collapsed state. The storage state detection sensor 90 detects that the free wheel 71 of the universal caster unit 70 is in the storage state. Then, the drive unit 11 detects that the tilt detection sensor 80 detects the state in which the placing surface portion 31 of the loading platform 30 is most tilted, and the storage state detection sensor 90 indicates that the free wheel 71 of the universal caster unit 70 is in the storage state. When detected, its operation is allowed. In other words, the lifting device 1 allows the operation of the drive unit 11 by detecting the state in which the mounting surface portion 31 is most tilted and the storage state of the free wheel 71 by the inclination detection sensor 80 and the storage state detection sensor 90. .

Specifically, the inclination detection sensor 80 and the storage state detection sensor 90 are limit switches attached to the frame 10, respectively. As shown in FIG. 10, the tilt detection sensor 80 is switched on / off (off) when a dog D 1 attached to the placement surface portion 31 of the loading platform 30 rotates together with the placement surface portion 31. ) Is switched. The tilt detection sensor 80 is switched on by the dog D1 when the placement surface portion 31 of the loading platform 30 rotates and the placement surface portion 31 is in the most collapsed state. As shown in FIGS. 8 and 9, the storage state detection sensor 90 is turned on / off when the dog D 2 attached to the base plate 72 of the universal caster unit 70 rotates together with the base plate 72. The storage state detection sensor 90 is switched on by the dog D2 when the base plate 72 is rotated and the free wheel 71 is in the protruding state (see FIG. 8).

Next, the operation of the lifting device 1 having the above configuration will be described. When carrying the load B accompanied by raising and lowering stairs by the lifting device 1, first, the load B is placed on the placement surface portion 31 of the loading platform 30. At this time, the loading platform 30 may be rotated around the rotation axis A1 to raise the placement surface 31 (see FIG. 5). Since the lower receiving portion 32 can be brought down by raising the placement surface portion 31, the position of the lower end of the front end of the two-tier shelf 33 can be lowered, and the load B can be easily placed on the loading platform 30.

In tilting the loading platform 30, first, the grip portion 41 of the handle 40 is gripped and the operation lever 41A is operated to release the state where the expansion and contraction of the support member 50 is locked. As a result, the support member 50 can be expanded and contracted, so that the loading surface 30 is tilted by rotating the mounting surface 31 around the rotation axis A1 by gripping the grip 41 and pushing and pulling the handle 40. It becomes possible. At this time, since the expansion / contraction lock of the support member 50 is released, an urging force in the extending direction by the support member 50 which is a gas spring acts. This urging force acts in a direction in which the loading platform 30 placement surface portion 31 rises. In other words, when the urging force acts against the gravity acting on the load B, the force necessary to tilt the loading platform 30 is reduced and can be easily tilted. Further, since the height of the handle 40 can be changed by tilting the loading platform 30, the handle 40 can be adjusted according to the physique of the operator of the lifting device 1 when traveling on flat ground and when moving up and down the stairs. The height can be adjusted to an appropriate height, and the lifting device 1 can be steered more easily.

When traveling on a flat ground, the lifting device 1 travels with the caster unit 60 and the universal caster unit 70. Specifically, as shown in FIG. 1, the caster unit 60 is such that the wheels 61 A and 61 B protrude below the lower surfaces of the pair of crawlers 20 in the lifting device 1 in a state of traveling on a flat ground. As shown in FIGS. 1 and 8, the universal caster unit 70 is in a protruding state in which the free wheel 71 protrudes from the lower surfaces of the pair of crawlers 20 in the lifting device 1 in a state of traveling on flat ground. As a result, the lifting device 1 travels on the caster unit 60 and the universal caster unit 70 with the wheels 61 A and 61 B and the free wheel 71 grounded while the pair of crawlers 20 is lifted when traveling on a flat ground.

When moving up and down the stairs, the lifting device 1 travels with a pair of crawlers 20. In raising and lowering the stairs by the elevating device 1, the placing surface portion 31 of the loading platform 30 is set in the most collapsed state, and the free wheel 71 of the free caster unit 70 is set in the housed state. Thereby, the inclination detection sensor 80 and the storage state detection sensor 90 work, and the operation of the drive unit 11 is allowed.

Specifically, as shown in FIG. 10, the inclination detection sensor 80 is switched on by the dog D1 when the placement surface portion 31 of the loading platform 30 rotates and the placement surface portion 31 is in the most collapsed state. It is said. Thereby, it is detected that the placing surface portion 31 of the loading platform 30 is in the most collapsed state. On the other hand, the storage state detection sensor 90 is switched on by the dog D2 attached to the base plate 72 of the universal caster unit 70 in the protruding state of the universal wheel 71 shown in FIG. Then, as shown in FIG. 9, when the locking of the fixed hook 73 by the solenoid actuator 74 is released and the base plate 72 is pulled and rotated by the tension spring 75, the free wheel 71 is also rotated to be in the housed state. At this time, the dog D2 also rotates with the rotation of the base plate 72, so that the storage state detection sensor 90 is switched off. Thereby, it is detected that the free wheel 71 is in the stored state. Thus, the operation of the drive unit 11 is allowed.

Then, the drive unit 11 is operated. Specifically, the pair of crawlers 20 is driven in a state where the crawlers 20 are in contact with the corners of the stairs S. Then, the crawler 20 advances along the corners of the stairs S, and the lifting device 1 moves up and down the stairs S. At this time, since the universal caster unit 70 is in the housed state, it does not interfere with the stairs S (see FIG. 11).

On the other hand, the caster unit 60 still protrudes downward from the lower surfaces of the pair of crawlers 20. However, as shown in FIGS. 11 and 12, when the

wheels

61A and 61B come into contact with the corners of the stairs S, the caster unit 60 contacts the stairs S by rotating the arm 62 around the rotation axis A3. The wheels 61 A and 61 B retracted inside the outer peripheral surface of the crawler 20. Thereby, the raising / lowering apparatus 1 can raise / lower the staircase S, without performing operation which stores the caster unit 60. FIG.

Further, the arm 62 is given a biasing force in the direction in which the wheel 61A is raised and the wheel 61B is lowered by the action of the tension spring 63. For this reason, the force received from the stairs S when the wheel 61A located on the upper side of the stairs S contacts the stairs S is easily converted by the force in the direction in which the wheels 61A are lifted. Further, the rotation axis A3 of the arm 62 is arranged eccentrically below the rotation axis A2 of the

wheels

61A and 61B. For this reason, the force received from the stairs when the

wheels

61A and 61B come into contact with the stairs is easily converted by the force in the direction in which the wheels 61A are lifted, and the arm 62 is reliably rotated. Thus, the raising and lowering of the stairs S is not hindered by the

wheels

61A and 61B interfering with the stairs S.

Next, when turning (changing direction) in a narrow place such as a stair landing, the support member 50 is unlocked in the manner described above, and the loading surface 31 of the loading platform 30 is raised (see FIG. 5). Thereby, the loading platform 30 and the handle 40 are accommodated between the front and rear ends of the crawler 20, the overall length of the lifting device 1 is shortened, and the turning radius of the lifting device 1 can be reduced. At this time, the wheels 61 A and 61 B of the caster unit 60 and the free wheel 71 of the free caster unit 70 are grounded, and turning is performed around the caster unit 60. In the lifting device 1, the caster unit 60 is disposed in the vicinity of the center of the pair of crawlers 20, and therefore the swivel can be performed with a smaller radius by swiveling around the caster unit 60. Further, since the

wheels

61A and 61B of the caster unit 60 and the universal wheel 71 of the universal caster unit 70 are grounded, stable turning is performed.

As described above, the lifting device 1 includes the frame 10, the crawler 20, the caster unit 60, and the universal caster unit 70. The frame 10 incorporates a drive unit 11. A pair of crawlers 20 is provided on the left and right sides of the frame 10 and is driven by the drive unit 11. The caster unit 60 is disposed near the center of the pair of crawlers 20 in plan view. The caster unit 60 has a plurality of

wheels

61A and 61B. The plurality of

wheels

61A, 61B protrude below the lower surface of the crawler 20 in a state of traveling on a flat ground and are arranged side by side in the front-rear direction. The universal caster unit 70 is disposed behind the caster unit 60. The universal caster unit 70 has a universal wheel 71. The universal wheel 71 is provided so as to be movable between a protruding state positioned below the lower surface of the crawler 20 in a state of traveling on a flat ground and a storage state positioned on the inner peripheral surface of the crawler 20 in a side view. .

With this configuration, the lifting device 1 turns around the caster unit 60 disposed near the center of the pair of crawlers 20 in plan view when turning. Further, at the time of turning, the free wheel 71 of the free caster unit 70 is in a protruding state, so that the free wheel 71 turns and turns. Thus, stable turning can be realized while reducing the turning radius.

Therefore, the lifting device of the present invention can be easily handled.

The elevating device 1 includes a storage state detection sensor 90 that detects that the free wheel 71 is in the storage state. The drive unit can be permitted to operate when the detection sensor detects the storage state. In this case, when the stairs are raised and lowered, the crawler is allowed to be driven in the stowed state where the free wheel does not interfere with the stairs, so that the safety during raising and lowering can be improved.

Further, when the elevating device 1 moves up and down the stairs S, the free wheel 71 is placed in the retracted state, and the

wheels

61A and 61B of the caster unit 60 that are in contact with the stairs S rotate the arm 62. The crawler 20 is retracted inside the outer peripheral surface. This operation is sequentially performed by the front and rear wheels 61 A and 61 B, so that the entire caster unit 60 can get over the corners of each step of the staircase S. As a result, the stairs S can be lifted and lowered satisfactorily.

The present invention is not limited to the first embodiment described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the first embodiment, the lifting device includes a specific configuration of a loading platform, a handle, and a support member, but this is not essential. The structure in the case where the lifting apparatus according to the present invention includes at least one of a cargo bed, a handle, and a support member is not particularly limited.
(2) In the first embodiment, the storage state detection sensor as a detection sensor for detecting the storage state of the free wheel of the universal caster unit, and the detection sensor for detecting a state in which the loading surface portion of the cargo bed has fallen more than a predetermined angle. However, these are not essential. When these detection sensors are provided, the detection sensor is not limited to the above-described limit switch, and other types of detection sensors such as a proximity sensor and a photoelectric sensor may be employed.
(3) In the first embodiment, the urging force of the tension spring is used to place the free wheel in the housed state. However, the present invention is not limited to this. For example, the housed state and the projecting state are switched by an actuator such as a cylinder or a motor. Form may be sufficient.
(4) In Embodiment 1, a rubber crawler is exemplified as the crawler, but a crawler using other materials such as a metal crawler or a crawler formed by a combination of these materials may be employed.
(5) In Embodiment 1, although the form which arranged the wheel of the caster unit along with the front-back direction was illustrated, the form arrange | positioned only at 1 row in the front-back direction may be sufficient. Moreover, in the caster unit of Embodiment 1, although the wheel was arrange | positioned along with the left-right direction, it was the form where only one wheel is arrange | positioned at the left-right direction.

DESCRIPTION OF SYMBOLS 1 ... Elevating device, 10 ... Frame, 10A ... Frame body part, 10B ... Motor mounting part, 10C ... Crawler guide part, 10D ... Front bearing part, 10E ... Rear bearing part, 11 ... Drive unit, 11A ... Motor, 11B ... Drive shaft, 11C ... Drive pulley, 12 ... Drive unit, 12A ... Drive shaft, 12B ... Drive pulley, 20 ... Crawler, 30 ... Loading platform, 31 ... Loading surface, 31A ... Lower end, 31B ... Upper end, 32 ... Lower Receiving part 33 ... 2 step shelf, 40 ... handle, 41 ... gripping part, 41A ... operating lever, 50 ... support member, 60 ... caster unit, 61A ... front wheel of caster unit, 61B ... rear side of caster unit Wheel, 62 ... Arm, 63, 75 ... Tension spring, 70 ... Swivel caster unit, 71 ... Swivel wheel, 72 ... Base plate, 73 ... Fixed hook 74 ... solenoid actuator, 74A ... locking claw 80 ... tilt sensor, 90 ... storage state detection sensor (detection sensor), B ... cargo, G ... flat ground, S ... staircase

Claims

A frame incorporating a drive unit;
A pair of crawlers provided on the left and right sides of the frame, and driven by the drive unit when moving up and down the stairs;
A caster unit having a wheel protruding downward from the lower surface of the crawler in a state of traveling on a flat ground, and disposed near the center in a plan view of the pair of crawlers;
Between the protruding state positioned below or below the lower surface of the crawler in a state of traveling on a flat ground and the storage state positioned inside the outer peripheral surface of the crawler in a side view, while being arranged in front of or behind the caster unit A free caster unit having freely movable wheels,
A lifting device characterized by comprising:
A detection sensor for detecting that the universal wheel is in the storage state;
The lifting device according to claim 1, wherein the drive unit is allowed to operate when the detection sensor detects the storage state.