JP2547426Y2 - Counterweight attachment / detachment device for mobile cranes - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for attaching and detaching a counterweight of a mobile crane.

[0002]

2. Description of the Related Art As shown in FIG. 7, a mobile crane has a boom 3 mounted on a swivel base 2 mounted on a lower traveling body 1 so as to be capable of swing drive. After the lower traveling body 1 is stably supported by the outriggers 1a, 1a,..., The swivel base 2 is turned, the boom 3 is raised and contracted, and the hook block 4 suspended at the end of the boom 3 is driven up and down. Crane is working. Swivel 2
A counterweight 5 is detachably attached to the rear end of the counterweight. The counterweight 5 is attached to the rear end of the swivel 2 during crane operation to increase the lifting capacity of the mobile crane, and is detached from the rear end of the swivel 2 when traveling to move. It is mounted on the upper weight mounting table 6 so as to balance weight during traveling movement.

Since the counterweight 5 is heavy,
The mounting position of the rear end of the swivel 2 and the weight mounting table 6
In order to move the counterweight 5 between the upper removal positions, an attachment / detachment device comprising a pair of left and right hydraulic cylinders 7 vertically attached with their piston rods 7a downward is attached to the rear end of the swivel 2. . After connecting the lower end of the piston rod 7a of each hydraulic cylinder 7 to the counterweight 5 via a detachable attachment / detachment device, these hydraulic cylinders 7 are driven to expand and contract to move the counterweight 5 to the rear end of the turntable 2. It is configured to be able to be driven up and down between the mounting position of the section and the removal position mounted on the weight mounting table 6. The weight mounting table 6 is provided below the counterweight 5 in a state where the swivel table 2 is swung to a specific swivel position (in the example of FIG. 7, the swivel position in which the boom turns to the rear of the lower traveling body 1). It is arranged to be located on the side.

When the counterweight 5 is to be detached, the swivel base 2 is turned to accurately move the counterweight 5 to the position where the weight can be attached or detached (attachment of the rear end of the swivel base 2). After stopping at the turntable 2 turning position where the weight mounting table 6 is located immediately below the counterweight 5 attached at the position (the state shown in FIG. 7), the pair of left and right hydraulic cylinders 7, 7 is lowered (extended). Drive to place the counter weight 5 on the weight mounting table 6,
Next, the connecting device between the lower end of each piston rod 7a and the counterweight 5 is released, and then the telescopic cylinders 7, 7 are driven up (reduced). When the counterweight 5 is mounted at the mounting position of the rear end of the swivel 2, the above operation is reversed.

In this type of mobile crane counterweight attaching / detaching device, the counterweight 5 is moved from a position where the rear end of the swivel 2 is mounted to a position where the lower traveling body 1 is removed from the weight mounting table 6. Alternatively, when lowering or ascending by the hydraulic cylinders 7 from the dismounting position to the mounting position, the turning position of the turntable 2 must be accurately stopped at the weight attaching / detaching position. If the telescopic cylinders 7, 7 are moved down (extended) while the turning position of the turntable 2 is not at the weight attaching / detaching position, the counterweight 5 is accurately moved to the weight placing table 6
This is because not only cannot it be mounted on the top, but also the centering of the connecting device between the counterweight 5 mounted on the weight mounting table 6 and the lower ends of the piston rods 7a, 7a cannot be performed. However, in the above-mentioned conventional attachment / detachment device, the telescopic cylinder 7,
Since the lowering (extension) drive of the counterweight 7 is possible, the mounting of the counterweight 5 on the weight mounting table 6 and the alignment of the connecting device often fail.

In addition, this type of counterweight attaching / detaching device for a mobile crane is provided with the lower end portions of the piston rods 7a, 7a when the swivel of the swivel base 2 is performed while the hydraulic cylinders 7, 7 are lowered (extended). The counterweight connected to the lower traveling body 1 via the connecting device collides with the structure of the lower traveling body 1 (for example, the weight mounting table 6), or the lower end of the piston rods 7a, 7a is mounted on the weight mounting table 6. The collision with the weight 5 causes the piston rod 7a,
There is a risk of damaging the structure of the lower traveling body 1 or 7a. However, in the above-mentioned conventional attachment / detachment device, the swivel base 2 is irrespective of the lowered (extended) state of the hydraulic cylinders 7, 7.
Since the turning drive is possible, the piston rods 7a and 7a or the structure of the undercarriage 1 are often damaged.

[0007]

The first object of the present invention is to make the lowering (extension) drive of the telescopic cylinders 7, 7 impossible unless the swivel 2 is accurately stopped at the weight attaching / detaching position.
The object is to achieve accurate mounting of the counterweight 5 on the weight mounting table 6 and accurate alignment of the connecting device. A second object of the present invention is to disable the swing drive of the swivel base 2 if the hydraulic cylinders 7, 7 have been lowered (extended) by a predetermined amount or more, so that the structure of the piston rods 7a, 7a or the undercarriage 1 can be reduced. In order to prevent the breakage.

[0008]

SUMMARY OF THE INVENTION In order to achieve the first object described above, a counterweight attaching / detaching apparatus for a mobile crane according to the present invention is provided.
And a fixed detector for detecting a fixed state of the turning fixing means, and a drive for raising and lowering (expanding and contracting) the hydraulic cylinders 7, 7. In a state where the fixed detector is interposed in an electric circuit for operating a solenoid-operated lifting hydraulic control valve to be controlled and the fixed detector does not detect the fixed state of the turning fixing means, the hydraulic pressure of the lifting hydraulic control valve is controlled. The operation to the cylinder 7, 7 lowering (extending) drive side is disabled.

Further, in order to achieve the second object, the counterweight attaching / detaching device of the mobile crane according to the present invention comprises:
In addition to the above configuration, a descent detector for detecting that the hydraulic cylinders 7, 7 have been lowered (extended) by a predetermined amount or more from the ascending (reducing) end position is attached.
When the descent detector detects that the hydraulic cylinders 7, 7 have descended by a predetermined amount or more, the swivel drive of the swivel 2 is disabled.

[0010]

The counterweight attaching / detaching device of the mobile crane according to the present invention having the above-mentioned structure is configured such that the turning position of the swivel 2 is fixed to the weight attaching / detaching position by the turning fixing means, and this state is not detected by the fixed detector. Since the extension cylinders 7 and 7 cannot be extended, accurate mounting of the counterweight 5 on the weight mounting table 6 and accurate alignment of the connecting device can be achieved. If the hydraulic cylinders 7, 7 have been lowered (extended) by a predetermined amount or more, the descent detector detects this and disables the swiveling drive of the swivel base 2, so that the piston rods 7a, 7a or the lower This can prevent the structure of the traveling body 1 from being damaged.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a counterweight attaching / detaching apparatus for a mobile crane according to the present invention will be described below with reference to FIGS. Since the present invention relates to the improvement of the counterweight attaching / detaching device of the conventional mobile crane, the reference numerals shown in FIG. 7 and described above as the prior art are synonymous and are used in the following description.

As shown in FIG. 2, a pair of left and right hydraulic cylinders 7 are fixed by abutting a flange 7c arranged at the piston rod side end of the cylinder 7b on a horizontal plate 2a forming the rear end of the swivel base 2. By doing so, the biston rod 7a is vertically provided at the rear end of the swivel 2 with the lower portion thereof. The piston rod 7a is configured to be able to expand and contract below the horizontal plate 2a at the rear end of the swivel 2 and has an engagement member 8 attached to its lower end. The counterweight 5 is provided with an engagement hole 9 for receiving the engagement tool 8. When the swivel base 2 is swung to the weight attaching / detaching position and the hydraulic cylinder 7 is driven down (extended), the engaging tool 8 is fitted into the engaging hole 9 of the counterweight 5 mounted on the weight mounting table 6. It has become. The engaging member 8 and the engaging hole 9 form a releasable connecting device 10 disposed between the lower end of the piston rod 7a and the counterweight 5.

In this embodiment, the engaging member 8 has a pair of 8a, 8a extending in the radial direction, and the two 8a, 8a are fitted in the engaging holes 9 of the counterweight 5. By twisting the engagement tool 8 by 90 °, a state in which the engagement tool 8 does not come out of the engagement hole 9, that is, a connection state of the connection device 10 is achieved. The torsion drive of the engagement tool 8 is performed by torsionally driving the piston rod 7a.

As shown in FIG. 3, a hydraulic rotary actuator 11 is mounted on the upper end of the cylinder 7b of the hydraulic cylinder 7 for torsional driving of the piston rod 7a. A rotary shaft 12 rotationally driven by a rotary actuator 11 penetrates the upper end wall of the cylinder 7b in an oil-tight rotatable manner, extends into the cylinder 7b, and expands and contracts in the cylinder 7b with a piston 7d at an upper end of a piston rod 7a. Engagement is impossible to rotate. According to this configuration, when the rotary actuator 11 is driven to rotate, the rotation shaft 12
, The piston rod 7a is torsionally driven.

In FIG. 3, reference numeral 13 denotes an expansion / contraction detecting rod which is rotatably engaged with the lower end of the piston rod 7a of the hydraulic cylinder 7 (to allow the piston rod to twist) and extends upward. . Reference numeral 14 denotes a drop detector which is closed when it detects that the hydraulic cylinder 7 has dropped from the ascending (reducing) end position by a predetermined amount or more. The descent detector 14 is constituted by a proximity switch arranged on the cylinder 7b side so as to deviate from the upper end of the telescopic detection rod 13 when the telescopic cylinder 7 has descended (extended) by a predetermined amount or more from the ascending (reducing) end position. ing.

Reference numeral 15 denotes a descent end detector which is closed by detecting the descent (extension) end position of the hydraulic cylinder 7. When the telescopic cylinder 7 descends to the descending (extending) terminal position, the descending end detector 15 detects the telescopic detection rod 13.
And a proximity switch arranged on the side of the cylinder 7b with a relation deviating from the upper end of the cylinder 7b.

As shown in FIGS. 4 and 5, the rotary actuator 11 comprises a casing 11a fixed to the cylinder 7a and a rotor 11b connected to the rotating rod 12 and oscillating and rotating within the casing 11a. It is composed of a swing motor. The rotary actuator 11 supplies the hydraulic oil from the supply / discharge port 11c and discharges the hydraulic oil from the supply / discharge port 11d, thereby rotating the rotor 1
4 by rotating the rotor 11b 90 degrees to the left in FIG. 4 by supplying hydraulic oil from the supply / discharge port 11d and discharging hydraulic oil from the supply / discharge port 11c.
° It is designed to rotate. Rotor 11b is 90 ° to the right
When rotated, the piston rod 7a is
And the engagement tool 8a of the coupling device 8 is twisted in the same direction, and the coupling device 10 is released. The rotor 11b is 90 ° to the left
When rotated, the piston rod 7a is
The engaging device 8a of the connecting device 8 is twisted in the same direction to connect the connecting device 10. Reference numeral 16 denotes a connection position detector whose detection end is disposed on the casing 11a in proximity to the outer peripheral surface of the rotary rod 12, and is configured by a proximity switch that detects the connection state of the connection device 10 and closes it. I have. 1
Reference numeral 7 denotes a release position detector whose detection end is disposed on the casing 11a close to the outer peripheral surface of the rotary rod 12, and is configured by a proximity switch that detects and closes the release state of the connection device 10. I have.

In FIG. 6, reference numeral 18 denotes a turning fixing means disposed between the swivel base 2 and the lower traveling body 1. The turning fixing means 18 includes a bracket 18a on the revolving base 2 side and a lower traveling body 1 side. Bracket 18b and these brackets 1
It is constituted by a pin 18c that can be inserted and removed freely and penetrates 8a and 18b. The fixed state of the turning fixing means 18, that is, the pin 1
When the bracket 8c penetrates both brackets 18a and 18b, the swivel 2 is fixed to the weight attaching / detaching position. Reference numeral 19 denotes a fixed detector which is closed by detecting the fixed state of the turning fixing means 18.
And a limit switch attached to the bracket 18a.

FIG. 1 shows a drive control circuit for the hydraulic cylinders 7, 7, a swing drive control circuit for the swivel 2, and a drive control circuit for the rotary actuators 11, 11. In FIG. 1, reference numeral 20 denotes a solenoid-operated lifting hydraulic control valve for controlling the raising and lowering (expansion and contraction) of the hydraulic cylinders 7, 7. ) Side oil chamber, and the other control oil passage is connected to the ascending (reducing) side oil chamber of each of the hydraulic cylinders 7, 7. 21 is a solenoid for switching the elevation hydraulic control valve 20 to the hydraulic cylinder 7, 7 descent (extension) drive side when energized;
Reference numeral 22 denotes a solenoid that switches the lifting hydraulic control valve 20 to the hydraulic cylinder 7, 7 raising (reducing) drive side when energized. An electric circuit for operating the elevating hydraulic control valve 20 includes an energizing circuit 24 for a solenoid 21 with a manual switch 23 interposed.
And a circuit 26 for energizing the solenoid 22 with a manual switch 25 interposed therebetween. The fixed detector 19 is interposed in the energizing circuit 24. That is, the fixed detector 19 is interposed in the electric circuit for operating the solenoid operated type elevating hydraulic control valve 20 for controlling the elevating drive of the hydraulic cylinders 7, 7. In the state where no detection is made, the operation of the lifting hydraulic control valve 20 to the hydraulic cylinder lowering drive side is disabled. Therefore, unless the turning table 2 is fixed to the weight attaching / detaching position by the turning fixing means 18, the hydraulic cylinders 7, 7 cannot be driven to descend (extend), so that the counterweight 5 can be accurately placed on the weight placing table 6 and Accurate alignment of the coupling device can be achieved. This configuration,
This corresponds to the invention of claim 1.

In FIG. 1, reference numeral 27 denotes a swing drive device for swingably driving the swivel base 2, which is driven and controlled by a swing hydraulic control valve 28. Reference numeral 29 denotes a solenoid-operated unload valve that is disposed between the tank and the pressure oil supply circuit 30 for the swing hydraulic pressure control valve 28 and is in an unloaded state when the solenoid 31 is energized and is in an on-load state when not energized. . When the unload valve 29 is in the unloaded state, the swing drive of the swivel base 2 is disabled. Unload valve 2
9 in the electric circuit 32 for energizing the solenoid 31
The drop detectors 14, 14 which detect and close the lowering (extension) of the hydraulic cylinders 7, 7 by a predetermined amount or more are interposed in parallel. That is, the descent detectors 14 and 14 that detect that the hydraulic cylinders 7 and 7 have descended from the ascending end position by a predetermined amount or more and the rotation drive device 27 of the swivel 2 are associated with each other.
When the hydraulic cylinders 4 and 14 detect the lowering of the hydraulic cylinders 7 and 7 by a predetermined amount or more, the swiveling drive of the swivel base 2 is disabled. For this reason, if the hydraulic cylinders 7, 7 have descended (extended) by a predetermined amount or more, the descending detectors 14, 14 detect this, and the swiveling drive of the swivel base 2 becomes impossible. Accordingly, damage to the piston rods 7a, 7a or the structure of the undercarriage 1 can be prevented. This configuration,
This corresponds to the invention of claim 2.

In FIG. 1, reference numeral 33 denotes an oscillating hydraulic control valve for controlling the oscillating drive of the rotary actuators 11, 11. The other control oil passages are connected to the other control oil passages 11d, 11d of the rotary actuators 11, 11, respectively. 34 is a solenoid for switching the swing hydraulic control valve 33 to one when energized, and 35 is a solenoid for switching the swing hydraulic control valve 33 to the other when energized. An electric circuit for operating the oscillating hydraulic control valve 33 has an electric circuit 36 connected to a power supply, a manual switch 37 interposed between the electric circuit 36 and the solenoid 34, and a manual switch 38 interposed between the electric circuit 36 and the solenoid 35. It is configured. In the electric circuit 36, the piston rods 7a of the hydraulic cylinders 7, 7,
Descending end detectors 15 and 15 that detect and close the descending (extending) end of 7a are interposed in series. According to this configuration, only when the hydraulic cylinders 7, 7 are at the descending (extending) end positions, the rotary actuators 11, 11 can be driven to swing, that is, the connecting and disconnecting of the connecting device 10 can be performed. It is possible to avoid a situation in which the connecting device 10 is accidentally released while the counterweight 5 is lifted in step 7.

In FIG. 1, reference numeral 39 denotes a connection position indicating lamp which is turned on when the connection position detectors 16, 16 detect the connection position of each connecting device 10. Reference numeral 40 denotes a release position indicator light that is turned on when the release position detectors 17, 17 detect the release positions of the respective coupling devices.

In the above embodiment, a description has been given of a case where the left and right hydraulic cylinders 7 are provided. However, the number of the hydraulic cylinders 7 may be arbitrarily determined. .

[0024]

According to the present invention, the counterweight attaching / detaching device of the mobile crane according to the present invention, which is constructed and operated as described above, drives the telescopic cylinders 7, 7 to descend (extend) unless the swivel 2 is accurately stopped at the weight attaching / detaching position. Therefore, accurate mounting of the counterweight 5 on the weight mounting table 6 and accurate centering of the connecting device can be achieved. If the hydraulic cylinders 7, 7 have been lowered (extended) for a predetermined amount or more, the swivel 2 cannot be swiveled.
Thus, damage to the structures a, 7a or the structure of the undercarriage 1 can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a hydraulic / electric circuit of a counterweight attaching / detaching device of a mobile crane according to the present invention.

FIG. 2 is a structural explanatory view of the counterweight attaching / detaching device of the mobile crane of the present invention. .

FIG. 3 is a sectional view taken along the line A in FIG. 2;

FIG. 4 is a cross section B of FIG. 3;

FIG. 5 is a cross section C of FIG. 3;

FIG. 6 is an explanatory view of a turning fixing means.

FIG. 7 is an explanatory view of a counterweight attaching / detaching device of the mobile crane.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Revolving base 5 Counter weight 6 Weight mounting table 7, 7 Hydraulic cylinder 10 Connecting device 14, 14 Descent detector 18 Rotation fixing means 19 Fixed detector 20 Elevating hydraulic control valve 27 Rotation driving device

Claims (2)

(57) [Scope of request for utility model registration] 1. A hydraulic cylinder is vertically installed with its piston rod downward at a rear end portion of a swivel table mounted on a lower traveling body so as to be capable of swiveling drive, and a lower end of the piston rod and a counterweight can be released. Connected via a simple connecting device,
By driving the hydraulic cylinder to expand and contract, the counterweight is driven up and down between a mounting position at the rear end of the swivel table and a removing position mounted on a weight mounting table arranged on the lower traveling body. configure the mosquito mobile crane
An unweighting attachment / detachment device, wherein the weight mounting table is arranged so as to be located below the counterweight in a state where the swivel table is swung to the weight attachment / detachment position, wherein the swivel table is provided between the swivel table and the lower traveling body. A swing fixing means which can be fixed to the weight attaching / detaching position in a swung state is attached, a fixed detector for detecting a fixed state of the swing fixing means is attached, and a solenoid-operated lifting / lowering controlling a lifting / lowering drive of the hydraulic cylinder is performed. In the state where the fixed detector is interposed in the operating electric circuit of the hydraulic control valve and the fixed detector does not detect the fixed state of the turning fixing means,
A counterweight attaching / detaching device for a mobile crane, wherein operation of the lifting hydraulic control valve on a hydraulic cylinder lowering drive side is disabled. 2. A descent detector for detecting that the hydraulic cylinder has descended from the ascending end position by a predetermined amount or more is attached, and the descent detector is associated with a swing drive device of the swivel base, and the descent detector is at least a predetermined amount of the hydraulic cylinder. The turning drive of the swivel table is disabled when the descent of the turntable is detected.
A counterweight attachment / detachment device for the mobile crane as described.