JP2008115008A - Fall prevention device of lifting magnet machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fall prevention device of a lifting magnet machine allowing even an unskilled operator to easily attract an attracting object having an appropriate weight to a lifting magnet, and of improving working property and efficiency. <P>SOLUTION: This fall prevention device of a lifting magnet machine is applied to a lifting magnet machine equipped with a lifting magnet 15 supported by a wire rope suspended from a boom attached to a work machine body, or a lifting magnet 15 attached to a tip of an articulated arm attached to a work machine body. The fall prevention device is provided with a control power supply device controlling attraction force of the lifting magnet 15, and a load detection means 19 detecting the load of the attraction object attracted to the lifting magnet 15. The control power supply device has an overload prevention means tentatively lowering the attraction force of the lifting magnet 15 to a value smaller than that of attraction force equivalent to a limit load WO when the load W detected by the load detection means 19 exceeds the limit value WO, and restoring the attraction force after the lowering. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an apparatus for preventing a lifting magnet machine from overturning due to an overload of an adsorbed substance attracted to the lifting magnet in a lifting magnet machine.

  A lifting magnet machine (hereinafter referred to as a lifting magnet machine, which may also be referred to as a lifting magnet machine) is a lifting magnet supported by a wire rope suspended from a boom attached to a work machine body, or Patent Document 1 As described in the above, a lifting magnet is attached to the tip of an articulated arm attached to the work machine body.

  Such riff mag machines are usually provided with a device that prevents overturning due to overload. In Patent Document 1, the equivalent load and work radius of the adsorbate are detected, and when the detected load exceeds the limit load at the current work radius, the operation in the direction of increasing the work radius is prohibited or a warning is issued. ing. If a warning is issued, the operator temporarily cuts off the current flowing through the riffmag coil by manual operation, drops a portion of the adsorbed material, and then flows the current through the coil again for adsorption. Work is being continued by absorbing objects.

Japanese Patent No. 2597984

  The maximum load that can be adsorbed to the riff mug varies depending on the material and mode of the adsorbate, and for example, a large adsorbent such as an iron block can adsorb a large load and accumulates randomly like iron scraps. Then, the load which can be adsorbed becomes small. For this reason, even if the same current is supplied to the riffmag coil, it may or may not be overloaded. Conventionally, in the case of an overload as described above, the operator manually turns off the current of the rifmag coil to drop the adsorbate, so that there is a problem that skill is required and the operation is not easy. In addition, when an unskilled operator operates, there is a problem that efficiency is deteriorated due to the fact that all of the adsorbate is dropped and a re-adsorption operation may be required.

  In view of the above-described problems, the present invention can prevent an unskilled operator from easily adsorbing an adsorbed material having an appropriate weight to a lift mug, thereby improving workability and work efficiency and preventing overturning of a lifting magnet machine. An object is to provide an apparatus.

The overturn prevention device for a lifting magnet machine according to claim 1 is attached to a lifting magnet supported by a wire rope suspended from a boom attached to the work machine body or a tip of an articulated arm attached to the work machine body. In lifting magnet machine with lifting magnet,
A control power supply for controlling the attractive force of the lifting magnet;
Load detecting means for detecting the load of the adsorbed matter adsorbed on the lifting magnet,
The control power supply device temporarily reduces the attracting force of the lifting magnet to a value smaller than the attracting force corresponding to the limit load when the load detected by the load detecting means exceeds the limit load, It has an overload prevention means for restoring the force.

The overturn prevention device for a lifting magnet machine according to claim 2 is attached to a lifting magnet supported by a wire rope suspended from a boom attached to the work machine body or a tip of an articulated arm attached to the work machine body. In lifting magnet machine with lifting magnet,
A control power supply device for controlling the attraction force of the lifting magnet, a load detection means for detecting the load of the adsorbed matter adsorbed on the lifting magnet,
Working radius calculating means for calculating a working radius of the lifting magnet;
A limit load setting means for determining a limit load corresponding to the working radius determined by the calculation means,
When the detected load detected by the load detection unit exceeds the limit load set by the limit load setting unit, the control power supply device uses the suction force corresponding to the limit load to adjust the suction force of the lifting magnet. It is characterized by having an overload prevention means for temporarily lowering to a small value and returning the adsorption force after the reduction.

The fall prevention device of the lifting magnet machine according to claim 3 is the fall prevention device of the lifting magnet machine according to claim 1 or 2,
The control power supply device controls the attracting force by controlling the voltage applied to the coil of the lifting magnet, and the overload prevention means is a means for controlling the voltage applied to the coil of the lifting magnet. It is characterized by.

The fall prevention device for a lifting magnet machine according to claim 4 is the fall prevention device for a lifting magnet machine according to any one of claims 1 to 3.
The overload prevention means of the control power supply device is configured to gradually reduce the suction force continuously or stepwise and restore the suction force when the detected load becomes equal to or less than the limit load. To do.

The fall prevention device of the lifting magnet machine according to claim 5 is the fall prevention device of the lifting magnet machine according to claim 2,
The overload prevention means further includes means for prohibiting an operation in a direction of increasing the work radius and / or issuing a warning when the detected load exceeds a limit load corresponding to the work radius. .

  According to the first aspect of the present invention, when the detected load exceeds the limit load at the time of ground cutting, the suction force of the riff mug is temporarily reduced to a value smaller than the suction force corresponding to the limit load. Can be dropped, and the riffmag machine can be prevented from falling. In addition, by properly setting the degree of decrease in adsorption force and time, it is possible to appropriately reduce the load of adsorbate without requiring skill, improving workability, and unskilled operators. Even so, you can work efficiently.

  According to the second aspect of the present invention, since the load is reduced in consideration of the work radius, fine and suitable control according to the situation at the work site can be performed.

  According to the third aspect of the present invention, the attracting force is controlled by the riff mug by controlling the voltage applied to the coil, and the attracting force is reduced by decreasing the voltage. Therefore, the attracting force can be controlled easily and finely.

  According to the invention of claim 4, when the detected load exceeds the limit load, the adsorption force is gradually reduced to drop a part of the adsorbate, so that the load of the adsorbent remaining in the state adsorbed on the riffmag is limited. A value close to the load can be obtained, and the efficiency is improved as compared with the case where the adsorbate is dropped due to a decrease in the adsorption force within a certain range.

  According to the invention of claim 5, since the operation in the direction of increasing the work radius after the ground cutting is prohibited or prevented, the work of the riff mag machine can be prevented more reliably in the work such as loading, unloading and stacking by the riff mag machine. be able to.

  FIG. 1 is a side view showing an embodiment of a riffmag machine according to the present invention. This riff mag machine uses an arm type, that is, an articulated arm. The working machine main body 1 of the riff mag machine includes a revolving unit 4 installed on a traveling unit 2 via a revolving device 3, and a revolving magnifying unit 4 including a building 5 or a cab 6 in which a power unit serving as a power source is built. Installed and configured. Reference numeral 7 denotes an articulated arm. The articulated arm 7 includes a boom 9 attached to the revolving body 4 by a boom cylinder 8 made of a hydraulic cylinder so as to be able to be raised and lowered, and an arm made of a hydraulic cylinder at the tip of the boom 9. An arm 11 rotatably attached by a cylinder 10 is provided, and a riff magnet 15 is rotatably attached to the tip of the arm 11 via a hydraulic cylinder 12, an arm link 13, and a work tool link 14.

  The riff mug 15 is provided by projecting an inner pole downward in the center of an outer pole having a circular bottom opening, winding a coil around the inner pole, and covering the lower face with a nonmagnetic material. The coil of the riff mug 15 is energized and controlled via a control power supply device 17 operated by an operator from an exterior generator 16 mounted on the building 5. The control power supply device 17 is provided in the cab 6 in this example, but may be provided in the exterior generator 16 or in the building 5.

  As shown in FIG. 2, a load detector 19 is attached to the base end portion of the boom cylinder 8. This load detector 19 does not detect the load of the adsorbate itself adsorbed on the riffmag 15, but detects the load including the weight of the articulated arm 7 and the riffmag 15, but the adsorbent adsorbed on the riffmag 15 The load that increases or decreases according to the increase or decrease of the load is detected.

  FIG. 3 is a functional block diagram illustrating functions of the control power supply device 17 of the riff mug 15. In FIG. 3, reference numeral 20 denotes a riffmag magnet excitation switch operated by an operator. 21 is a rectifier that rectifies the output of the exterior generator 16 that is an AC generator, 22 is a DC-DC converter, and 23 is higher than usual in the coil of the riffmag 15 for a predetermined time from when the switch 20 is turned on. This is a first timer that applies a voltage to reduce the delay in the rise of the current. As shown in FIG. 4 (B), 24 is a second timer for allowing the operation of reducing the attractive force only for a time T3 that is considered to be necessary for ground cutting, and its output is the switch 20 turned on. After that, the current flowing through the riffmag 15 is output after a time T2 that is assumed to be stable.

  Reference numeral 25 denotes a limit load setting means, and 26 denotes an input means such as a switch or a keyboard for setting the limit load W0 in the limit load setting means 25 by an external operation. Reference numeral 27 denotes comparison means for comparing the limit load W0 set by the limit load setting means 26 with the detected load W detected by the load detector 19. A third timer 28 temporarily reduces the voltage to the DC-DC converter 22 by the output of the comparison means 27 that displays that the detected load W exceeds the limit load W0.

  FIG. 4 is a time chart for explaining the operation and operation of the control power supply device of FIG. 4A shows the on / off state of the switch 20, FIG. 4B shows the output of the second timer 24, FIG. 4C shows the change in load due to the adsorbed matter adsorbed on the riff mug 15, and FIG. Indicates the output of the comparison means 26, (E) indicates the output of the third timer 27, (F) indicates the voltage applied to the coil of the riffmag 15, and (G) indicates the current flowing through the coil of the riffmag 15. .

  As shown in FIGS. 3 and 4, first, when the operator places the riff mug 15 on the adsorbent and closes the switch 20 as shown in FIG. 4 (A), the first timer 23 is started, and the coil of the riff mug 15 is moved. As shown in FIG. 4F, an initial voltage V1 (for example, 200 V) higher than a standard voltage V2 (for example, 200 V) applied to the coil for adsorption for a time T1 set by the timer 23 is used. 290V).

  Then, the adsorbate is adsorbed to the riff mug 15, and the riff mug 15 is raised by the extension of the boom cylinder 8 of the articulated arm 7 and / or the contraction of the arm cylinder 10 to perform ground cutting. After the time T2 when the current is assumed to have risen sufficiently after the switch 20 is turned on, the second timer 24 has a time T3 that is considered to be necessary for the operation of removing the overload due to the earth cutting or the lowering of the adsorbate. Meanwhile, the switch 24a is closed, the output of the comparison means 27 is allowed (or operation is allowed), and the subsequent output (or operation) is prohibited. In this example, as shown in FIG. 4C, since the load W detected by the load detector 19 exceeds the limit load W0, the output of the comparison means 27 is turned on as shown in FIG. 4D. As a result, the third timer 28 turns on the output for the set time T4 as shown in FIG. As a result, the DC-DC converter 22 only during this time T4 (the set time T4 of the third timer 28 is set to a time sufficient for the reduction of the adsorption force and the fall of the adsorbate for overload elimination). The voltage V3 that is normally applied to the coil of the riffmag 15 is set to a voltage (for example, a voltage between 100 V and 160 V) lower than the standard voltage V2 (200 V) that is normally applied, and the attractive force is made smaller than the attractive force corresponding to the limit load.

  As a result, when the current flowing through the coil of the riffmag 15 is reduced as shown in FIG. 4G, the attracting force by the riffmag 15 is reduced, so that a part of the adsorbed matter adsorbed on the riffmag 15 is dropped. As shown in FIG. 4C, the load of the adsorbed matter adsorbed on the riff mug 15 becomes W2 which is the limit load W0 or less. When the set time T4 of the third timer 28 elapses and the output is turned off, as shown in FIG. 4F, the output voltage of the DC-DC converter 22, that is, the voltage applied to the coil of the riff magnet 15 is The original voltage V2 is restored, and the current i flowing through the coil of the riffmag 15 is also restored to the original current as shown in FIG. If the original current is restored, this current is sufficient to attract the adsorbed matter remaining in the riff mug 15, and there is no risk of dropping.

  As described above, in this embodiment, when the detected load W exceeds the limit load W0 when the ground is cut, the suction force of the riff mug 15 is temporarily reduced from the normal suction force. Can be dropped. For this reason, the load W2 of the adsorbate adsorbed by the riff mug when the attraction force is restored can be reduced to the limit load W0 or less to prevent the riff mug machine from overturning.

  In addition, by appropriately setting the voltage reduction level and time applied to the coil of the riff mug 15 and appropriately setting the degree and time of reduction of the adsorption power, the load of the adsorbate can be appropriately adjusted without requiring skill. It can be reduced, workability is improved, and even an unskilled operator can work efficiently.

  Further, as in this embodiment, if the limit load W0 set in the limit load setting means 25 can be changed by the input means 26 from the outside, this limit is determined according to the properties of the adsorbate at the work site. By changing the load W0, the load of the adsorbate can be reliably set to the limit load W0 or less, and the work efficiency is improved.

  In this embodiment, the load that can be adsorbed to the riffmag 15 when the fall is considered in accordance with the increase / decrease of the working radius (the distance from the turning center of the swiveling device 3 to the riffmag 15) accompanying the expansion / contraction of the articulated arm 7. If the limit load W0 is set assuming that it is the maximum working radius in consideration of the increase or decrease of the sway, it will prevent the fall from happening regardless of the working radius in all the processes from the ground cutting to the release of the adsorbate. can do. Further, the limit load W0 may be a limit load at a work radius smaller than the maximum work radius if an operation in the direction of increasing the work radius is prohibited or a warning is issued by increasing or decreasing the work radius as will be described later.

  The load detector 19 is not provided in the boom cylinder 8 but is provided with a load detector on the pin 29 that connects the riff magnet 15 and the arm 11 and the pin 30 that connects the work tool link 14 and the riff magnet 15. The load detected by the load detector may be calculated and used as the load.

  The load detector 19 does not use the output signal as it is as the load detection means, but processes the detection signal to reduce the load on the articulated arm 7 or the riffmag 15, that is, the adsorbed material. A load detection means that includes an arithmetic means for calculating an equivalent load is used as a load detection means, or further, the load on the articulated arm 7 or the riffmag 15 is reduced in accordance with the increase or decrease in the working radius to obtain an equivalent load to the adsorbate. What added the calculation means to obtain | require may be used, and what processed the limit load W0 corresponding to the process of the detection load W may be used.

  Alternatively, the third timer 28 may be omitted, and the output voltage of the DC-DC converter 22 may be restored when the output of the comparison unit 27 is turned off. Note that the voltage to be restored is not necessarily the same as the previous voltage. Further, the standard voltage V2 may be set and changed according to the situation, for example, the standard voltage V2 can be set in a plurality of stages.

  In addition, the second timer 24 is configured so that the attraction force of the riff mag 15 is output by the output of the comparison means 27 when the output of the load detector 19 increases rapidly during turning after the ground is cut or when the boom cylinder 8 or the arm cylinder 10 is extended. The second timer 24 and the switch 24a are not necessarily provided, although the second timer 24 and the switch 24a are not necessarily provided.

  FIG. 5 shows another embodiment of the present invention. In this embodiment, the working radius r given by the working radius calculating means 33 is inputted to the working radius setting means 25A, and the limit load W0 corresponding to the working radius is shown. Is calculated. Here, when the calculation is performed by the work radius setting means 25A, the work radius is determined depending on the properties of the adsorbed matter by means such as multiplying the calculation result by a coefficient or subtracting by the input of a signal from the input means 26. It is preferable to be able to increase or decrease the calculation result of the limit load for. The working radius setting means 25A obtains the limit load W0 for the working radius r by calculation in advance and stores it in the storage means. When the working radius r is given, the limit corresponding to the working radius r is stored from the stored value. The load W0 may be read out.

The working radius r is the distance A from the turning center of the turning device 3 to the pin 31 for attaching the boom 9 to the turning body 4, and the pin 32 for connecting the boom 9 and the arm 11 to the pin 31 for attaching the boom 9 to the turning body 4. Is the length of B, the angle formed by the line connecting the pins 31 and 32 with respect to the horizontal line is α, the distance from the pin 32 to the pin 29 connecting the riffmag 15 and the arm 11 is C, and between the pins 29 and 32 If the angle between the line connecting and the horizontal line is β,
r = A + Bcosα + Ccosβ
It becomes. The working radius r may be determined in consideration of one or both of the inclination angle of the work implement body 1 and the distance from the pin 29 to the center of the bottom surface of the riffmag 15. Similarly to the above, if the detected load W exceeds the limit load W0, an operation of temporarily reducing the output voltage to the coil of the riff mug 15 is performed.

  Further, in this embodiment, there are provided means for prohibiting and warning the operation in the direction of increasing the work radius r accompanying the decrease of the limit load accompanying the increase of the work radius r accompanying the expansion and contraction of the articulated arm 7. The configuration for prohibiting the operation and warning will be described below.

  Reference numerals 34 and 35 are control valves for the boom cylinder 8 and the arm cylinder 10, respectively. 36a and 36b are contraction side valve portions and extension side valve portions of the pilot valve 36 of the boom cylinder control valve 34, and 37a and 37b are arm arms. A contraction side valve portion and an extension side valve portion 39 of the pilot valve 37 of the cylinder control valve 35 are pipes between the contraction side valve portion 36 a of the pilot valve of the control valve 34 and the contraction side operation oil chamber of the control valve 34. The prohibition valve 40 is provided in a pipe line between the contraction side valve portion 37 a of the pilot valve 37 of the control valve 35 and the contraction side operation oil chamber of the control valve 35. 41 is an alarm generator.

  In this configuration, when the operation radius r is increased by the operation of the articulated arm 7 after the ground cutting, the limit load setting means 25A corresponding to the work radius r calculated by the work radius calculation means 33 is performed. When the result of comparing the limit load W0 obtained by the above and the detected load W detected by the load detector 19 by the comparison means 27 is W> W0, that is, in the case of an overload, the inhibition valve The control valves 34 and 35 are switched to the contraction side, that is, the boom cylinder 8 and the arm cylinder 10 are switched to the contraction side by switching 39 and 40 to the shut-off position, thereby preventing the working radius r from increasing and preventing overturning. . If the output of the comparison means 27 indicates an overload, an alarm is generated by the alarm generator 41 (including sound) or the alarm lamp is turned on or blinked to warn the operator. To emit.

  By prohibiting the operation in the direction of increasing the work radius during overloading or issuing a warning, the operation in the direction of increasing the work radius after ground cutting is prohibited or prevented, so loading, unloading, stacking, etc. with a riff mag machine In this work, it is possible to prevent the riff mag machine from falling down more reliably.

  In the embodiment of FIG. 5, the output of the comparison means 27 is used for both the control at the time of earth cutting and the control for the subsequent fall prevention. However, the limit load for the control at the time of earth cutting and the subsequent fall prevention is as follows. Each may be set separately, and accordingly, the comparison means may be provided separately.

  FIG. 6 is a block diagram showing another embodiment of the present invention, and FIG. 7 is a time chart thereof. This embodiment differs from that shown in FIG. 3 in that, instead of the third timer 28, a DC-DC converter is used while the output of the comparison means 27 is on, that is, an overload. 22 is provided with a signal generating means 42 that continues to lower the output voltage 22.

  In this embodiment, as shown in FIG. 7C, when the load W at the time of earth cutting is an overload W1, the output of the comparison means 27 is turned on as shown in FIG. In response to this turned-on signal, the signal generating means 42 continues to issue a command signal for gradually decreasing the voltage to the DC-DC converter 22, and the output voltage of the DC-DC converter 22 gradually decreases as shown in FIG. . As a result, the attracting force by the riffmag 15 gradually decreases, and when a part of the adsorbed material falls from the riffmag 15 and the detected load W becomes, for example, W2 which is equal to or less than the limit load W0, the output of the comparison means 27 is turned off. The output of the generating means 42 is turned off, and the DC-DC converter 22 returns the voltage.

  In this way, if the voltage applied to the coil is reduced by the output of the comparison means 27 and the output voltage is restored when the detected load W becomes less than or equal to the limit load W0, the detected load W exceeds the limit load W0. In this case, since the adsorption force is gradually reduced to drop a part of the adsorbate, the load of the adsorbate remaining in the state where it is adsorbed to the riff mug can be brought to a value close to the limit load, and the adsorption force is reduced within a certain range. As a result, the efficiency is improved as compared with the case where the adsorbate is dropped. In this embodiment, the mode in which the voltage applied to the coil is gradually reduced in the event of an overload is assumed to be continuous. However, this voltage decrease is stepwise, for example, 10 V is decreased at regular intervals. May be. Further, the mode of gradually decreasing the voltage as in this embodiment can also be applied to a control device that takes into account the working radius as shown in FIG.

  The present invention can also be applied to a riffmag machine having a structure in which a wire rope is suspended from a boom attached to a work machine body and the riffmag is supported by the wire rope.

It is a side view which shows one Embodiment of the riffmag machine to which the fall prevention apparatus by this invention is applied. It is a side view which shows an example of the attachment structure of the load detector of this Embodiment. It is a block diagram which shows one Embodiment of the fall prevention apparatus by this invention. It is a time chart explaining operation and operation | movement of the fall prevention apparatus of FIG. It is a block diagram which shows other embodiment of the fall prevention apparatus by this invention. It is a block diagram which shows other embodiment of the fall prevention apparatus by this invention. It is a time chart explaining operation and operation | movement of the fall prevention apparatus of FIG.

Explanation of symbols

1: work machine main body, 2: traveling body, 3: swiveling device, 4: swiveling body, 5: building, 6: cab, 7: articulated arm, 8: boom cylinder, 9: boom, 10: arm cylinder, 11: Arm, 12: Hydraulic cylinder, 13: Arm link, 14: Work tool link, 15: Riffmag, 16: Exterior generator, 17: Control power supply, 19: Load detector, 20: Riffmag magnet excitation Switch: 21: Rectifier, 22: DC-DC converter, 23: First timer, 24: Second timer, 25, 25A: Limit load setting means, 26: Input means, 27: Comparison means, 28: Third Timer, 29 to 32: pin, 33: working radius calculation means, 34, 35: control valve, 36, 37: pilot valve, 39, 40: inhibition valve, 41: alarm generator, 42: signal generation means

Claims (5)

In a lifting magnet machine having a lifting magnet supported by a wire rope suspended from a boom attached to the work machine body, or a lifting magnet attached to the tip of an articulated arm attached to the work machine body,
A control power supply for controlling the attractive force of the lifting magnet;
Load detecting means for detecting the load of the adsorbed matter adsorbed on the lifting magnet,
The control power supply device temporarily reduces the attracting force of the lifting magnet to a value smaller than the attracting force corresponding to the limit load when the load detected by the load detecting means exceeds the limit load, An overload prevention device for a lifting magnet machine, comprising overload prevention means for restoring force. In a lifting magnet machine having a lifting magnet supported by a wire rope suspended from a boom attached to the work machine body, or a lifting magnet attached to the tip of an articulated arm attached to the work machine body,
A control power supply device for controlling the attraction force of the lifting magnet, a load detection means for detecting the load of the adsorbed matter adsorbed on the lifting magnet,
Working radius calculating means for calculating a working radius of the lifting magnet;
A limit load setting means for determining a limit load corresponding to the working radius determined by the calculation means,
When the detected load detected by the load detection unit exceeds the limit load set by the limit load setting unit, the control power supply device uses the suction force corresponding to the limit load to adjust the suction force of the lifting magnet. An overload prevention device for a lifting magnet machine, characterized by having an overload prevention means for temporarily lowering to a small value and restoring the attractive force after the reduction. In the fall prevention device of the lifting magnet machine according to claim 1 or 2,
The control power supply device controls the attracting force by controlling the voltage applied to the coil of the lifting magnet, and the overload prevention means is a means for controlling the voltage applied to the coil of the lifting magnet. A fall prevention device for lifting magnet machines. In the fall prevention apparatus of the lifting magnet machine in any one of Claim 1 to 3,
The overload prevention means of the control power supply device is configured to gradually reduce the suction force continuously or stepwise and restore the suction force when the detected load becomes equal to or less than the limit load. To prevent falling magnet machine. In the fall prevention device of the lifting magnet machine according to claim 2,
The overload prevention means further includes means for prohibiting an operation in a direction of increasing the work radius and / or issuing a warning when the detected load exceeds a limit load corresponding to the work radius. Lifting prevention device for lifting magnet machine.

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