JP2003112889A - Safety device for crawler crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety device for preventing the fall-down or breakage of a crawler crane. SOLUTION: In mounting/demounting a side frame, the crawler crane is jacked up by a jack cylinder 6. Pressure sensors 6b, 6r mounted on the jack cylinder 6 detect the mounted condition of the side frame such that the side frame exists or not and is grounded or not. A controller 20 estimates the mounted condition of the side frame in accordance with the detection result of the pressure sensors 6b, 6r and outputs a command signal to a moment limiter 21 for selecting a rated load curve corresponding to the mounted condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a crawler crane having a jack-up device and capable of adjusting the position of a crawler belt.

[0002]

2. Description of the Related Art Conventionally, work machines such as crawler cranes have been known which are provided with a device for changing a distance between left and right side frames. For example, at the time of work, the space between the side frames is widened to enhance the stability of the machine body. On the other hand, when the crawler crane is transported to the work site, the space between the side frames is reduced according to the width of the trailer or the like on which the crawler crane is loaded. In addition, the side frame may be removed when the crawler crane is loaded on the trailer.

[0003]

The side frame is removed when the crawler crane is jacked up. The side frame is attached and detached by hoisting the crawler belt with a crane or the like, but depending on the crawler crane, the side frame may be hoisted by itself to attach and detach the side frame.
However, when the crawler crane is in a jacked-up state, the stability is worse than when working with a normal crawler crane in which the side frames on both sides are grounded, so the worker needs to work carefully, Workability is not good.

An object of the present invention is to provide a safety device for a crawler crane which can prevent the crawler crane from falling or being damaged.

[0005]

A safety device for a crawler crane according to the present invention has a side frame which is expanded and contracted with respect to a track frame and is detachable from the track frame, so that the track frame is jacked up. Applies to equipment. Then, one of the rated load curves is selected from a plurality of rated load curves and a detection device that detects the mounting state of the side frame with respect to the track frame, depending on the mounted state of the side frame detected by the detection device. The above object is achieved by including a selecting device and a control device that controls the operation of the crawler crane based on the rated load curve selected by the selecting device.

The detection device further detects the turning position of the upper swing body of the crawler crane with respect to the lower traveling body of the crawler crane, and the selection device determines which of the mounting positions of the side frames and the swing position of the upper swing structure the final swing position. It is preferable to select that rated load curve.

A safety device for a crawler crane according to the present invention is applied to a safety device for a crawler crane which has a side frame which expands and contracts with respect to a track frame and is detachable from the track frame so as to jack up the track frame. Then, based on the state of attachment of the side frame attached to the track frame and the state of attachment of the side frame detected by the detector, it is determined whether or not the turning operation is possible. The above-mentioned object is achieved by including a control device that controls to prohibit.

The detecting device further detects the turning position of the upper swing body of the crawler crane with respect to the lower traveling body of the crawler crane, and the control device turns based on the mounting state of the side frame and the swing position of the upper swing body. May be determined.

The detection device preferably detects whether or not the side frame is attached to the track frame. Further, the detection device preferably detects whether or not the side frame is in contact with the ground. The detection device may detect the position of the side frame from the center of the crawler crane.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION << First Embodiment >> An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a crawler crane equipped with a crawler crane safety device according to the present invention. FIG. 2 is a view of the crawler crane shown in FIG. 1 viewed from the direction of arrow A, and is a front view. The crawler crane includes a lower traveling body 100 and a lower traveling body 10 via a turning device 110.
The upper revolving structure 120 is connected to 0 so as to be revolvable, and the front attachment 130 is provided on the front part of the upper revolving structure 120 so as to be capable of undulating. Also, the upper swing body 1
A counterweight CW for balancing the machine body during work is attached to the rear portion of 20.

In FIG. 3, the lower traveling body 100 is indicated by an arrow B in FIG.
It is the figure seen from the direction. As shown in FIGS. 1 to 3, the undercarriage 100 includes a substantially H-shaped track frame 1 provided with a turning device 110 and a side frame 2. The side frame 2 includes a crawler belt 5 wound around a driving wheel 3 attached to one end of the side frame 2 and a driven wheel 4 attached to the other end. Furthermore, the lower traveling body 100 includes a jack cylinder 6 that supports the crawler crane by jacking up when the side frame 2 is attached or detached. Two jack cylinders 6 are provided in each of the front portion and the rear portion of the track frame 1. The side frame 2 can be expanded and contracted in the left-right direction in FIG. 3 by the side frame expansion / contraction cylinder 2a. Two side frame expansion / contraction cylinders 2a are provided on the track frame 1, and the left and right side frames 2 can be expanded / contracted separately. In addition, in FIG.
The side frame telescopic cylinder 2a is shown in the most extended state, and the side frame 2 is at the longest position from the center line 0 of the track frame 1.

The position of the side frame 2 from the center line 0 of the track frame 1 is changed according to the working condition of the crawler crane. For example, at the time of work such as hoisting a suspended load, the side frame telescopic cylinder 2a is extended to make the position from the center line 0 of the side frame 2 the longest and widen the space between the left and right side frames 2. Thereby, the stability of the airframe can be improved.

When the machine body is transported, the side frame expansion / contraction cylinder 2a is contracted in accordance with the width of a vehicle such as a trailer on which the machine body is loaded to narrow the space between the left and right side frames 2. Further, depending on the crawler crane, the side frame 2 may be removed and loaded on the trailer when the aircraft is transported to the site. When the side frame 2 is removed and the machine body is transported, the side frame 2 is attached at the work site. The attachment / detachment work of the side frame 2 is performed with the crawler crane being jacked up.

In the crawler crane equipped with the safety device according to the present invention, the side frame 2 is lifted by itself to be mounted and removed. Also, the counterweight CW may be lifted and mounted by itself.
The safety device for a crawler crane according to the present invention prevents the crawler crane from tipping over and the jack cylinder from being damaged when working with the machine body jacked up. Here, as work to be carried out with the jack up, the crawler crane setup (side frame,
(Removal of counter weight etc.) work etc. The jack-up operation of the crawler crane and the attachment / detachment operation of the side frame 2 will be described below.

As shown in FIGS. 2 and 3, the jack cylinder 6 is fixed to the track frame 1 on the bottom chamber side, and the cylinder rod extends downward in FIG. 2 and contracts upward. In order to prevent the cylinder rod from undesirably extending, the jack cylinder 6 is provided with a rod lowering prevention plate (not shown). Further, a pedestal 6a, which serves as a scaffold for the jack cylinder 6 when jacking up the machine body, is attached to the side surface of the jack cylinder 6.

The jack-up operation of the crawler crane is performed as follows. First, the pedestal 6a is removed from the jack cylinder 6 and set right under the jack cylinder. When the jack cylinder 6 is extended, the cylinder rod is grounded via the pedestal 6a. After that, when the jack cylinder 6 is continuously extended, the crawler crane main body is lifted with the four pedestals 6a as fulcrums. This operation is usually performed remotely using a remote controller or the like. The four jack cylinders 6 can be driven separately.

The procedure for removing the side frame 2 from the track frame 1 will be described below. After jacking up the crawler crane, lift the side frame 2.
The side frame telescopic cylinder 2a is extended while adjusting the lifting of the side frame 2. The side frame telescopic cylinder 2a is extended to the longest position shown in FIG. 3, and the pin 2b connecting the cylinder 2a and the side frame 2 and the pin 2c connecting the track frame 1 and the side frame 2 are removed. After that, the side frame 2 is lifted and moved, and the side frame 2 is moved to the track frame 1.
Remove from. Similarly, remove the side frames 2 on both the left and right sides.

Also, when mounting the side frame 2, the side frame 2 is lifted by the crane while the crawler crane is jacked up, and the side frame 2 is mounted on the track frame 1. The extension / contraction operation of the side frame extension / contraction cylinder 2a can also be remotely performed using a remote controller or the like.

As described above, when the side frame 2 is self-attached / detached while the crawler crane is jacked up, the suspended load is hoisted in the jacked up state. Generally, a work machine such as a crawler crane is equipped with a moment limiter for preventing the work machine from tipping over or damaging a boom. In the moment limiter, the limit load of the load that can be lifted at a predetermined working radius (total rated load) is stored as a rated load curve. The moment limiter selects a rated load curve according to the working radius based on the boom undulation angle and the like, and performs overload prevention control along the selected rated load curve.

Since the usual crawler crane hangs the suspended load with the side frames 2 on both the left and right sides contacting the ground, the stability of the machine body is higher than that in the jacked-up state. In other words, when hoisting a load such as a side frame with the crawler crane jacked up, if the same rated load curve as in normal crawler crane work is selected and overload prevention control is performed, the crawler crane will not fall or jack up. The cylinder may be damaged.

Therefore, in the safety device for a crawler crane according to the first embodiment of the present invention, in order to safely operate the crawler crane, it is determined whether or not the side frame is attached to the track frame, and the side frame. Select the optimum load curve according to the mounting condition of the side frame, such as whether or not is grounded on the ground.

FIG. 4 shows a front view of the crawler crane with one side frame 2 removed after jacking up. Here, assuming that the position of the upper swing body 120 in the crawler crane shown in the front view of FIG. 2 is the reference position (0 degree), the upper swing body 120 shown in FIG. 4 is in a state of being swung 90 degrees to the right. Further, the crawler crane is jacked up by the jack cylinder 6, the left side frame 2 is removed, and the right side frame 2 is not grounded, and the track frame 1 bears its weight.

FIG. 5 is an enlarged view showing the right side portion of the lower traveling body 100 of the crawler crane shown in FIG.
In the first embodiment of the present invention, the mounting state of the side frame 2 is detected by the pressure acting on the jack cylinder 6. The pressures of the bottom chamber and the rod chamber of each of the four jack cylinders 6 are detected by a pressure sensor, and the attachment states of the left and right side frames 2 are estimated based on the detected pressures. The relationship between the jack pressure and the mounting state of the side frame 2 is set in advance. Here, the mounting state of the side frame 2 detected by the jack pressure includes the following. (1) Presence / absence of side frame: Whether or not the side frame 2 is attached to the track frame 1. The presence or absence of the left and right side frames is detected. (2) Grounding of side frame: Side frame 2
Is on the ground, or is it on track frame 1? (3) Position of side frame: How far the side frame 2 is from the center of the track frame 1.

Further, as shown in FIG.
There are four limit switches 31a, 31b, 3 near the
1c and 31d are provided, and these limit switches 3
The turning positions (turning angles) of the upper-part turning body 120 with respect to the lower-part traveling body 100 are detected at 90-degree intervals by 1a to 31d.

FIG. 6 is a schematic diagram showing the structure of a safety device for a crawler crane according to the first embodiment. A pressure sensor 6 is provided in each of the conduits that connect the rod chambers and bottom chambers of the four jack cylinders 6 to a hydraulic source (not shown).
r and 6b are provided. The pressures of the four jack cylinders 6 detected by the pressure sensors 6r and 6b are input to the controller 20. The turning position of the upper swing body 120 detected by the limit switches 31a to 31d is also input to the controller 20.

A moment limiter 21 is connected to the controller 20. The moment limiter 21 is
It has a memory that stores a plurality of rated load curves according to the attachment state of the side frame 2 as a table. The controller 20 estimates the current mounting state of the side frame 2 based on the input pressure of the jack cylinder 6 and the swing position of the upper swing body 120. And
The controller 20 outputs to the moment limiter 21 an instruction signal for selecting a rated load curve according to the mounting state of the side frame 2. Moment limiter 2
1 selects an optimum rated load curve from a plurality of rated load curves stored in the memory based on an instruction signal from the controller 20. The moment limiter 21 controls ups and downs of the boom and hoists of the hook based on the selected load curve, and controls overload prevention of the crawler crane.

7 and 8 show the state of attachment of the side frame 2 and the turning position (turning angle) of the upper swing body 120 estimated by the controller 20 in order to select the optimum rated load curve. FIG. 7 shows a case where the side frames 2 are attached to one of the left and right sides, and FIG. 8 shows a case where both the left and right side frames 2 are attached. The angles of the left and right and the turning position mentioned here are based on the posture of the crawler crane shown in FIG. For example, in the case of the crawler crane shown in FIG. 4, the side frame 2 is attached only to the right side, and the upper swing body 1
It is assumed that the turning position of 20 is 90 degrees.

As shown in FIG. 7, when the side frame 2 is attached to either the left or right side, the rated load curve is selected based on the following conditions (a) to (d). (A) Mounting position of the side frame 2 (right / left) (b) Position of the side frame 2 (whether the distance from the center of the track frame 1 to the side frame 2 is the longest or the shortest) (c) The grounding of the side frame 2 Existence (d) Revolving position of upper revolving structure 120

Here, the state as shown in FIG. 4, that is,
(A) Only the right side of the side frame 2 is attached,
(B) The position of the side frame 2 from the center of the track frame 1 is the longest, (c) the side frame 2 is not in contact with the ground, and (d) the swing position of the upper swing body 120 is 90.
If it is degrees (hatched portion in FIG. 7), the minimum rated load curve a is selected from the rated load curves stored in the moment limiter 21.

As shown in FIG. 8, when the side frames 2 are attached to both right and left sides, the following (b) to
The rated load curve is selected based on the condition shown in (d). (B) Position of the side frame 2 (whether the distance from the center of the track frame 1 to the side frame 2 is the longest or the shortest) (c) Presence or absence of grounding of the side frame 2 (d) Revolving position of the upper swing body 120

Here, when (b) the position of the side frame 2 from the center of the track frame 1 is the longest, and (c) the side frames 2 on both the left and right sides are in contact with the ground (hatched portion in FIG. 8), Since this is the same state as when the normal crawler crane is in operation, the maximum rated load curve c is selected from the rated load curves stored in the moment limiter 21. Note that the maximum rated load curve c here is set according to the side frame attachment state, and in the actual working state of the crawler crane, a plurality of rated load curves are set based on the boom length and the like. To be done. Also,
Even when the left and right side frames 2 are removed, the rated load curve is selected accordingly.

As shown in FIG. 7, when the side frame 2 is mounted only on the right side, there are 16 mounting states and turning positions of the side frame 2. When setting the rated load curve, it is possible to set the rated load curve corresponding to each of the 16 conditions, store it in the moment limiter 21, and select it. Alternatively, the 16 conditions may be divided into several groups, and the rated load curves corresponding to the groups may be set.

The selection of the rated load curve based on the mounting state of the side frame 2 and the turning position has been described above with reference to FIGS. 7 and 8. However, under conditions different from the state of the crawler crane shown in the shaded area in FIG.
In some cases, the minimum rated load curve a may be selected. Selection of the rated load curve according to the mounting state of the side frame 2 and the turning position differs depending on the model and design of the crawler crane, and FIGS. 7 and 8 show an example for selecting the rated load curve. is there. The conditions for selecting the rated load curve are not limited to those shown in FIGS. 7 and 8. For example, when the side frame 2 shown in FIG. 8 is attached to both sides, (b) the side frame 2
Position of one is the longest and the other is the shortest,
(C) One side frame 2 may be grounded and the other may be ungrounded.

As described above, in the safety device for the crawler crane according to the first embodiment of the present invention, the rated load curve is selected based on the mounted state of the side frame and the swing position of the upper swing body. did. As a result, even when the crawler crane is jacked up, the operation of the crawler crane is controlled along the optimum load curve, so that the crawler crane can be prevented from tipping over or the jack cylinder is damaged.

It should be noted that the rated load curve may be selected only according to the mounting state of the side frame. In this case, a rated load curve that does not fall over regardless of the turning position of the upper swing body may be selected.

<< Second Embodiment >> In a crawler crane safety device according to a second embodiment of the present invention, the state of attachment of the side frame 2 detected in the first embodiment and the upper swing body 120 are detected. Based on the turning position,
When there is a possibility that the crawler crane may fall, the upper swing body 120 is prohibited from swinging. The attachment state of the side frame 2 and the detection of the turning position of the upper-part turning body 120 are the same as those in the above-described first embodiment.

When the upper revolving structure 120 to which the front attachment 130 is attached is revolved in a jack-up state, depending on the state of the crawler crane, it may fall down,
The jack cylinder 6 may be damaged. Therefore, when the attachment state of the side frame 2 is detected and the crawler crane is likely to tip over, the swing operation of the upper swing body 120 is prohibited. In the mounted state of the side frame 2 and the swing position of the upper swing body 120 shown in FIG. 7, for example, (a) the side frame 2 is mounted only on the right side, and (b) the side frame 2 is located at the longest position from the center of the track frame 1. , (C) the side frame is not grounded, and (d) the swing position of the upper swing body 120 is 9
When it is 0 degree (hatched portion), it is determined that there is a possibility of falling, and the upper revolving superstructure 120 is prohibited from revolving.

The controller 2 determines whether the upper revolving structure 120 is prohibited from revolving according to the mounting state of the side frame 2.
It is done at zero. When the controller 20 determines that the upper revolving structure 120 is prohibited from turning, the rotation of the turning hydraulic motor is stopped in response to a command signal to prohibit turning. The operation of the safety device for the crawler crane according to the second embodiment of the present invention will be described below with reference to FIG.

FIG. 9 shows the structure of a safety device for a crawler crane according to the second embodiment. To rotate the upper swing body 120, the operation lever 43 is operated. The pilot pressure according to the operation amount of the operation lever 43 is the hydraulic pressure source 4
It is supplied from 0 to the pilot port of the control valve 44. The control valve 44 is switched according to the pilot pressure to control the flow of pressure oil supplied from the main pump 46 to the swing hydraulic motors 45a and 45b.
The upper swing body 120 is driven to swing by the rotation of the swing hydraulic motors 45a and 45b.

Pilot valves 43a, 4 of the operating lever 43
In the pipeline between 3b and the control valve 44, electromagnetic switching valves 41a and 41b for turning are provided, respectively. The electromagnetic switching valves 41a and 41b for turning are switched by a command signal from the controller 20. When the electromagnetic switching valves 41a and 41b for turning are respectively in the position b, the pilot pressure corresponding to the operation of the operation lever 43 is supplied to the control valve 44.

The controller 20 determines whether or not to prohibit the upper revolving structure 120 from revolving as described above. When the controller 20 determines that the upper revolving structure 120 is prohibited from revolving, a revolving prohibition command signal is output to the solenoids of the electromagnetic switching valves 41a and 41b for revolving. The electromagnetic switching valves 41a, 41b for turning are switched to the position a in response to the command signal for turning prohibition, and prohibit the flow of pressure oil from the hydraulic pressure source 40 to the control valve 44. As a result, the control valve 44 switches to the neutral position,
The rotations of the turning motors 45a and 45b are stopped.

Further, a swing disc brake generally provided as a brake device for stopping the swing of the upper swing body 120 can be additionally used. The swing disc brakes 46a and 46b are used for the swing motors 45a and 4a.
Disc 47 for swing brake provided on the output shaft of 5b
a, 47b and swing brake discs 47a, 47b
And hydraulic cylinders 48a and 48b having pads 49a and 49b to be pressed against both sides of. Also, the hydraulic power source 40
An electromagnetic switching valve 42 for controlling the flow of pressure oil supplied from the hydraulic cylinders 48a, 48b to the hydraulic cylinders 48a, 48b is provided. At the position a, the electromagnetic switching valve 42 connects the hydraulic source 40 to the hydraulic cylinder 48a,
The flow of pressure oil to 48b is permitted, and the flow of pressure oil from the hydraulic power source 40 to the hydraulic cylinders 48a and 48b is prohibited at the position b.

The electromagnetic switching valve 42 is controlled by the controller 20 and is in the position b by the spring force when the operation lever 43 is not operated. To the controller 20, switches S1 and S2 that are switched by the pilot pressure supplied to the control valve 44 are connected. When the switches S1 and S2 are switched by the pilot pressure supplied to the control valve 44, the controller 20 accordingly outputs a command signal to the solenoid of the electromagnetic switching valve 42. The electromagnetic switching valve 42 is switched to the position a by this command signal. As a result, pressure oil from the hydraulic pressure source 40 is supplied to the rod chambers of the hydraulic cylinders 48a, 48b, the pads 49a, 49b pressed against the brake discs 47a, 47b are separated from the discs 47a, 47b, and the turning motor 45a, Allow rotation of 45b.

Here, the controller 20 causes the upper swing body 1 to move.
When it is determined that the turning of 20 is prohibited, the output of the command signal to the solenoid of the electromagnetic switching valve 42 is cut off. As a result, the electromagnetic switching valve 42 is switched to the position b. Hydraulic cylinder 4
8a and 48b communicate with the tank, and the pads 49a and 49b are pressed against the brake discs 47a and 47b by a spring force to operate the swing brake.

As described above, in the second embodiment, the mounting state of the side frame 2 and the upper swing body 1
Whether or not the upper-part turning body 120 can turn is determined according to the turning position of 20. When it is determined that turning is prohibited, the control valve 44 is switched to the neutral position by switching the electromagnetic switching valves 41a and 41b for turning, and the turning motor 45a,
The rotation of 45b is prohibited. Accordingly, when there is a possibility of tipping over depending on the mounting state of the side frame 2 and the swing position of the upper swing body 120, the swing operation of the crawler crane can be prohibited, and the work can be performed safely. . In addition, in response to a command signal for prohibiting the turning from the controller 20, the electromagnetic switching valves 41a, 4a for turning, 4 and
By switching 1b and switching the electromagnetic switching valve 42 to the position b, the upper revolving structure 120 can be more reliably operated.
The rotation of can be stopped.

The safety device for the crawler crane in the second embodiment is also the same as in the first embodiment described above.
Depending on the model and design of the crawler crane, the upper swing structure 12
The conditions for prohibiting the turning of 0 are different. The above-described conditions for prohibiting the swing of the upper swing body 120 shown in FIG. 7 are examples, and in the crawler crane safety device according to the second embodiment of the present invention, the swing of the upper swing body 120 is prohibited. The condition is not limited to the example of FIG. 7. Note that the turning position of the upper turning body 120 may not be used, and whether or not the turning operation is possible may be determined only by the attachment state of the side frame 2. In this case, the upper swing body 12
It suffices to permit the turning motion only when there is no possibility of tipping over regardless of the turning position of 0.

The turning prohibition control by the safety device according to the second embodiment can be combined with the safety device according to the first embodiment. For example, in the first embodiment, since the rated load curve is selected in consideration of the turning position, it is not necessary to select the safety-side rated load curve that does not tip over when the vehicle makes a full turn. Therefore, the turning operation may be performed, and the turning operation may be prohibited when the safety degree due to the turning becomes equal to or less than a predetermined value.

<< Third Embodiment >> In the third embodiment, the detection of the attachment state of the side frame 2 is performed.
Use the limit switch. The process for selecting the rated load curve or determining whether to prohibit turning is the same as in the first and second embodiments described above. FIG. 10 shows an enlarged view of the right side portion of the front view of the lower traveling body 100. Here, the side frame 2 is the center line 0 of the track frame 1.
In the longest position, the side frame 2 contacts the ground and supports the weight of the crawler crane. The jack-up cylinder 6 is only in contact with the ground on the pedestal 6a.

The track frame 1 has side frames 2
Switches 11 and 12 for detecting the mounting state of the
Is provided. The limit switch 11 detects the horizontal mounting position of the side frame 2 with respect to the track frame 1, that is, the position from the center line 0 of the track frame 1. The limit switch 12 is a vertical position of the side frame 2 with respect to the track frame 1,
That is, it is detected whether the side frame 2 is in contact with the ground.

The horizontal and vertical positions of the side frame 2 detected by the limit switches 11 and 12 are input to the controller 20 together with the turning position of the upper swing body 120 detected by the limit switch 31. The controller 20 estimates the mounting state of the side frame 2 based on the input signal, and selects a rated load curve according to the mounting state or the upper swing body 1
The control processing of the turning prohibition determination of 20 is performed.

<< Fourth Embodiment >> In the fourth embodiment, the detection of the attachment state of the side frame 2 is performed.
Use limit switches and pressure sensors. The process for selecting the rated load curve or determining whether to prohibit turning is the same as in the first and second embodiments described above. FIG. 11 shows an enlarged view of the right side portion of the front view of the lower traveling body 100. Here, the side frame 2 is located at the longest position from the center line 0 of the track frame 1, and the side frame 2 is in contact with the ground to support the weight of the crawler crane. The jack-up cylinder 6 is only in contact with the ground on the pedestal 6a.

The track frame 1 has a side frame 2
A limit switch 11 and a pressure sensor 13 for detecting the mounting state of the pressure sensor are provided. Limit switch 11
Detects the horizontal mounting position of the side frame 2 with respect to the track frame 1, that is, the position from the center line 0 of the track frame 1. The pressure sensor 13 is composed of a load cell or the like, and detects whether the side frame 2 is in contact with the ground or is on the track frame 1.

The horizontal position of the side frame 2 detected by the limit switch 11 and the load cell 13 and the presence or absence of ground contact are input to the controller 20 together with the turning position of the upper swing body 120 detected by the limit switch 31. The controller 20 estimates the mounting state of the side frame 2 based on the input signal, and selects a rated load curve according to the mounting state or performs a control process for determining whether to turn the upper swing body 120.

As described above, in the safety device for the crawler crane according to the present invention, the mounting state and the turning position of the side frame are detected, and the rated load curve corresponding to the mounting state and the turning position is selected or the upper swing body is selected. Control of turning prohibition was performed. As a result, when the side frame is self-detached while the crawler crane is jacked up or when a counterweight is attached, lifting work of the suspended load is performed in a state different from the working state as a normal crawler crane. Moreover, it is possible to prevent the crawler crane from falling and the jack cylinder from being damaged.

In addition, the mounting state of the side frame is
(A) Presence / absence of a side frame (whether or not the side frame is attached), (b) Presence / absence of grounding of the side frame, (c) Position from the center of the track frame and detailed detection, and (d) Upper part The mounting position of the side frame was estimated by detecting the turning position of the revolving structure. As a result, it is possible to reliably detect the attachment state of the side frame and perform control according to it.

In the embodiment described above,
Although a pressure sensor for detecting the pressure of the jack cylinder, a limit switch for detecting the position of the side frame, a load cell, and the like are used as the detection device for detecting the attachment state of the side frame, the present invention is not limited to this.
Further, the number of limit switches for detecting the turning position of the upper swing body with respect to the lower traveling body is not limited to four, and the position of the upper swing body may be detected using at least two limit switches.

[0057]

As described above, the safety device for the crawler crane according to the present invention detects the mounting state of the side frame and selects the rated load curve according to the mounting state. In addition, based on the state of attachment of the side frame, if there is a possibility that the crawler crane may fall, the turning motion is prohibited. As a result, the work can be performed safely when the side frame is self-attached / detached in a jacked-up state, and the workability is improved.

[Brief description of drawings]

FIG. 1 is a side view of a crawler crane equipped with a safety device according to an embodiment of the present invention.

2 is a front view of the crawler crane of FIG.

FIG. 3 is a view of the lower traveling body as seen from above.

FIG. 4 is a diagram showing an example of a state when setting up a crawler crane.

FIG. 5 is an enlarged view of a right side portion of the lower traveling body.

FIG. 6 is a diagram showing a configuration of a safety device for a crawler crane according to a first embodiment of the present invention.

FIG. 7 is a diagram showing an example of a side frame attached state.

FIG. 8 is a diagram showing an example of a side frame attached state.

FIG. 9 is a diagram showing a configuration of a safety device for a crawler crane according to a second embodiment of the present invention.

FIG. 10 is an enlarged view of the right side portion of the lower traveling body.

FIG. 11 is an enlarged view of the right side portion of the lower traveling body.

[Explanation of symbols]

1: Track frame 2: Side frame 5: Track 6: Jack cylinder 6r, 6b: pressure sensor 11, 12, 13, 31: Limit switch 20: Controller 100: Undercarriage 120: Upper swing body 130: Front attachment

Claims (7)

[Claims] 1. A safety device for a crawler crane, which has a side frame that expands and contracts with respect to a track frame and is detachable from the track frame, so that the track frame is jacked up. And a selection device that selects one of the rated load curves from a plurality of rated load curves according to the mounting state of the side frame detected by the detection device, and a selection device selected by the selection device. And a control device for controlling the operation of the crawler crane based on the rated load curve thus obtained. 2. The safety device for a crawler crane according to claim 1, wherein the detection device further detects a turning position of an upper swing body of the crawler crane with respect to a lower traveling body of the crawler crane, and the selection device is A safety device for a crawler crane, wherein any one of the rated load curves is selected according to the mounting state of the side frame and the swing position of the upper swing body. 3. A safety device for a crawler crane, which has a side frame that expands and contracts with respect to the track frame and is detachable from the track frame, so that the track frame can be jacked up. And a control device that determines whether or not the turning operation is possible based on the attachment state of the side frame detected by the detection device, and controls to prohibit the turning operation when it is determined that the turning operation is prohibited. A crawler crane safety device comprising: 4. The safety device for a crawler crane according to claim 3, wherein the detection device further detects a turning position of an upper swing body of the crawler crane with respect to a lower traveling body of the crawler crane, and the control device includes A safety device for a crawler crane, wherein whether or not a turning operation is possible is determined based on a mounting state of the side frame and a turning position of the upper turning body. 5. The safety device for a crawler crane according to any one of claims 1 to 4, wherein the detection device detects whether or not the side frame is attached to the track frame. Safety device for crawler crane. 6. The safety device for a crawler crane according to any one of claims 1 to 4, wherein the detection device detects whether or not the side frame is grounded. Crawler crane safety device. 7. The safety device for a crawler crane according to claim 5 or 6, wherein the detection device detects a position of the side frame from a center of the crawler crane. Safety device.