JP3238577B2 - Counterweight attachment / detachment device and counterweight position adjustment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, various devices for attaching and detaching a counterweight of a mobile crane have been developed. For example, in a device disclosed in Japanese Utility Model Laid-Open No. 5-82982, a gantry cylinder for raising and lowering the A frame is provided.
It has two counter cylinders suspended from the A frame shaft connecting the front and rear legs of the A frame. With the counterweight and the distance between the counterweight and the A-frame axis set appropriately, the gantry cylinder is extended and retracted, and the counterweight is moved along an appropriate movement path to avoid interference between the counterweight and the body frame. Weights are attached and detached.

[0003]

When the counterweight is fastened to the body frame by bolts, it is necessary to adjust the counterweight in the vertical direction and also in the horizontal direction. However, in this conventional apparatus, the only way to adjust the position in the vertical and horizontal directions is to pry the counterweight with a bar or the like. There are problems that the operability is not so much improved and the time required for attachment and detachment is not shortened much.

An object of the present invention is to provide a counterweight attaching / detaching apparatus capable of improving the operability of attaching / detaching a counterweight and shortening the attaching / detaching time.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 7 showing an embodiment, the present invention is characterized in that a front leg 3a and a rear leg 3b are connected by an A-frame shaft 3c, and a non-working posture is obtained. The present invention is applied to a counterweight attachment / detachment device for a crane provided with an A-frame 3 that moves between the work posture and the A-frame hydraulic cylinder 7. The purpose of the above is to set the counterweights (41, 4) at a predetermined angle that is not orthogonal to the A-frame axis 3c and so as not to be parallel to each other.
2 and 43) and a pair of suspension brackets (41
a, 42a, 43a) and the A frame shaft 3c, respectively, and a pair of weight lifting / lowering hydraulic cylinders 10, and supply / discharge control valves 21, 22 for individually controlling the supply / discharge of pressure oil of the pair of lifting / lowering hydraulic cylinders 10, respectively. This is achieved by providing: The weight attachment / detachment device according to claim 2, wherein one end of each of the pair of weight lifting / lowering hydraulic cylinders 10 is connected to the A frame shaft 3c at a central portion of the A frame shaft 3c while restraining the movement in the axial direction.
1 is provided. Its connection bracket 1
As shown in FIG. 5, a pair of bracket bodies 11a are provided so as to be fitted on the A-frame shaft 3c, and are slidable on the A-frame shaft 3c by themselves. And connecting members 11b and 11c which are integrated at a distance of. Claim 4
The weight attachment / detachment device is characterized in that it has a spreader 13 for maintaining the interval between the piston rods of the pair of weight lifting hydraulic cylinders 10 at the interval between the pair of suspension brackets (42a, 43a). As shown in FIG. 7, the weight attaching / detaching device according to claim 5 has a supply / discharge control valve 21,
22 and a pair of weight lifting hydraulic cylinders 1
A pair of flow control valves 25 and 26 are provided to control the flow supplied to each of the zeros. According to a sixth aspect of the present invention, in the method for adjusting the position of the counterweight using the counterweight attaching / detaching device according to the first aspect, the supply / discharge control valves 21 and 22 are arranged such that the lengths of the piston rods of the pair of weight lifting hydraulic cylinders 10 are different. Are operated individually.

[0006]

When the pair of hydraulic cylinders 10 are individually operated to expand and contract individually, the counterweights (41, 42, 43) slightly move up, down, left and right, and fine positioning can be performed. The connection bracket 11 of the third aspect is not fixed to the A frame shaft 3c, but receives the reaction force of the pair of hydraulic cylinders 10 from the left and right, and the mounting position does not move. The spreader 13 maintains the interval between the piston rods of the pair of weight lifting hydraulic cylinders 10 at the interval between the pair of suspension brackets (42a, 43a). In order to synchronize the operation of each hydraulic cylinder 10, the flow control valves 25,
At 26 the flow rate is adjusted.

In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a counterweight attaching / detaching apparatus according to the present invention is applied to a self-propelled crawler crane will be described below with reference to FIGS. 2 and 3, a self-propelled crane includes a crawler type lower traveling body 1 and an upper revolving body 2 rotatably provided on the lower traveling body 1.
A crane boom (not shown) provided at a front portion of the upper revolving unit 2, an A frame 3 supporting the crane boom with an up-and-down rope, and a counter detachably provided at a rear end of the upper revolving unit 2. And a weight 4.

As shown in FIG. 4, the counter weight 4 has a three-piece structure including an inner weight 41, a center weight 42, and an outer weight 43. A pair of suspension brackets 41a are fixed to the inner weight 41 at relatively narrow intervals, and a through hole 41b for a bolt for attaching the inner weight itself to the upper rotating body 2 is provided.
And screw holes 41c for bolts for mounting the center weight 42, screw holes 41d for bolts for mounting the center weight and the outer weight, and penetration of bolts for fixing the three weights together to the upper revolving unit 2. Hole 41
e is provided. A pair of suspension brackets 42a are fixed to the center weight 42 at relatively wide intervals, and a bolt through hole 42c for attaching the center weight itself to the inner weight 41 is provided.
A through hole 42e corresponding to the hole 41e and a bolt through hole 42d for attaching the outer weight 43 to the inner weight 41 together with the center weight 42 are provided. A pair of suspension brackets 43a are fixed to the outer weight 43 at the same interval as the center weight 42, and bolt through holes 43e corresponding to the holes 41e for attaching three weights to the upper swing body 2 collectively. A bolt through hole 43d for attaching the outer weight 43 to the inner weight 41 together with the center weight 42 is provided.

1 to 4, an A frame 3 includes a pair of left and right front legs 3a, a pair of left and right rear legs 3b, and a pair of front and rear legs 3a.
a and 3b are connected at their upper ends so as to be rotatable. The lower end of the front leg 3a is rotatably connected to a bracket (not shown) provided on the upper swing body 2 by a front leg connecting pin. The rear leg 3b is configured to be telescopic, and the lower end of the lower component is connected to the upper revolving frame 2
Is rotatably connected to a bracket (not shown) provided by a rear leg connecting pin. As is well known, the A frame shaft 3c is provided with a sheave 5 and an A frame hanger 6, and a boom hoisting rope from a boom hoist winch mounted on the main body frame 2 is provided with a plurality of sheaves 5 from the sheave 5 in the A frame hanger 6. It is routed between the sheave and a bridle (not shown), and the undulating rope end is connected to the A frame shaft 3c.

An A-frame hydraulic cylinder 7 is provided between the upper frame 2 and the center of the A-frame shaft 3c.
3 is moved from the non-working posture P3 in FIG. 3 to the working posture P1 through the intermediate posture P2. Also,
The reverse operation is performed by contraction of the hydraulic cylinder 7.

In FIGS. 1 and 2, reference numeral 10 denotes a weight lifting / lowering hydraulic cylinder constituting a counterweight attaching / detaching device, which is suspended by a bracket 11 at the center of an A frame shaft 3c. As shown in detail in FIG. 5, the bracket 11 has a pair of left and right fan-shaped plates 11a, bolts 11c connecting the pair of plates 11a via spacers 11b, and is fixed to lower ends of the left and right plates 11a. And a hydraulic cylinder mounting bracket 11d. And
The bracket 11 is attached to the shaft 3c so that the A-frame shaft 3c passes through a hole 11e formed in the center of the plate 11a. The protrusion 11f provided on the inner surface of the plate 11a is used for positioning the hydraulic cylinder 7 for raising and lowering the A frame.

A tube end of the counterweight elevating hydraulic cylinder 10 is connected to each of the hydraulic cylinder mounting brackets 11d. A counterweight connecting link 12 (FIG. 1) is connected to the piston rod ends of the pair of hydraulic cylinders 10 by pins, and a spreader 13 is interposed between the brackets 12 to provide a piston of the pair of hydraulic cylinders 10. Increase the spacing between rods.

As shown in FIG. 6, the spreader 13 has a shaft portion 13 having a length corresponding to the mounting width of the suspension brackets 42a, 43a of the center weight 42 and the outer weight 43.
a and engagement portions 13b provided at both ends of the shaft portion 13a. Each engaging portion 13 is engaged with each end of a pin connecting the end of each piston rod to the connecting link 12, the interval between the piston rods is made substantially the same as that of the suspension brackets 42a, 43a, and each end of the piston rod is used as a counterweight. The workability of connecting has been improved.

That is, if the distance between the piston rods is not increased by the spreader 13, when connecting the ends of the piston rods to the center weight 42 and the outer weight 43, the operator must connect the piston rod end of the hydraulic cylinder 10 to the counterweight. To the left and right of the hanging bracket width, which is a considerable labor. Therefore, the gap is widened by the spreader 13 in advance.

FIG. 7 is a hydraulic circuit diagram of the counterweight attaching / detaching device. Reference numerals 21 to 23 denote supply / discharge control valves for adjusting the supply amount of pressurized oil to the counterweight elevating hydraulic cylinder 10 and the A-frame hydraulic cylinder 7, respectively, 24 a hydraulic pump,
25 to 27 are flow control valves for adjusting the amount of oil flowing into each hydraulic cylinder from the hydraulic pump 24 to adjust the expansion and contraction speed of each hydraulic cylinder. 28 and 29 extend the piston rod of the counterweight elevating hydraulic cylinder 10. A balancing valve that opens when pressure oil flows in the direction to allow oil discharge, and opens when pressure oil flows in the direction to contract the piston rod of the A-frame hydraulic cylinder 7 to allow oil discharge. It is a valve.

The operation when the outer weight 43 is hung by the counterweight attaching / detaching device constructed as described above will be described with reference to FIG. The description will be made assuming that the inner weight 41 and the center weight 42 are attached first. The self-propelled crane is moved with the A frame 3 folded, and the axis of the A frame shaft 3c is aligned with the position of the suspension bracket 43a of the outer weight 43. With the spreader 13 attached when the center weight 42 is attached, the supply / discharge control valves 21 and 22 are simultaneously operated downward to extend the weight lifting hydraulic cylinder 10 and connect the connection link 12 to the suspension bracket 43a. Thereafter, the supply / discharge control valves 21 and 22 are simultaneously operated to the raising side to contract the weight lifting hydraulic cylinder 10 and lift the weight 43.

By operating the supply / discharge control valve 23 in the upward direction, A
The frame hydraulic cylinder 7 is extended to move toward the upper revolving superstructure 2 while the weight 43 is suspended. When the weight 43 moves to the weight mounting position, the operation of the supply / discharge control valve 23 is stopped, and the supply / discharge control valve 21 is stopped.
22 at the same time, the weight lifting hydraulic cylinder 1
0 is extended, and the outer weight 43 is lowered to a position where the outer weight 43 is connected to the center weight 42. The supply / discharge control valves 21 and 22 are individually operated to extend and retract the pair of right and left weight lifting hydraulic cylinders 10 to align the weight mounting through hole 43b with the corresponding through hole of the center weight 42. The outer weight 43 is attached to the upper revolving unit 2 with a bolt via the center weight 42 and the inner weight 41 using mounting bolts.

When attaching the inner weight, the suspension bracket 41a of the inner weight 41 is used.
Is narrower than the outer weight 43. Therefore, the spreader 13 needs to be removed. Further, since the height position of the suspension bracket 41a is low, a connecting link separately prepared between the weight lifting hydraulic cylinder 10 and the suspension bracket 41a is required.

The procedure for removing the weight is the reverse of the procedure for attaching the weight, and a description thereof will be omitted. When the weight lifting hydraulic cylinder 10 is not used, the weight lifting hydraulic cylinder 10 is fixed to the upper swing body 2 with a fixing wire rope.

The above embodiment has the following operational effects. When suspending the weight, the weight is lifted by the weight lifting hydraulic cylinder 10 and the weight and the A frame shaft 3 are lifted.
c is shortened to a predetermined distance, and then the weight is brought close to the upper revolving unit 2 while the weight is lifted by the A-frame hydraulic cylinder 7, so that the weight does not collide with the weight attaching portion of the upper revolving unit 2. Can be hung up above.

The tube ends of a pair of weight lifting / lowering hydraulic cylinders 10 are integrally attached to the center of the A-frame shaft 3c by brackets 11 respectively, and the hydraulic cylinders 10 are not orthogonal to the A-frame shaft 3c but at a predetermined angle (FIG. 1). In this case, the weight is finely adjusted left and right and up and down by individually adjusting the amount of expansion and contraction of each counterweight elevating hydraulic cylinder 10 because it is suspended and can be operated individually. This makes it extremely easy to position the mounting holes. In the case where a pair of weight lifting / lowering hydraulic cylinders 10 are arranged orthogonal to the A-frame shaft 3c, respectively, as in the counterweight attaching / detaching device disclosed in Japanese Utility Model Laid-Open No. 5-82982 described in the conventional example. However, it is difficult to finely operate the left and right of the counterweight even if each of them can be individually expanded and contracted.

Since the tube ends of the pair of weight lifting hydraulic cylinders 10 are attached to the center of the A frame shaft 3c, the bending moment generated on the A frame shaft is reduced, which is advantageous in strength.

When the piping distance between the supply / discharge control valves 21 and 22 and the weight lifting hydraulic cylinders 10 is different, when the supply / discharge control valves 21 and 22 are simultaneously operated, the expansion and contraction speed of each hydraulic cylinder cannot be synchronized. There is a supply / discharge control valve 2
Flow control valve 25,
26 is provided, and the amount of oil supplied to each hydraulic cylinder can be adjusted, so that the pair of hydraulic cylinders 10 can be accurately synchronized.

When the distance between the suspension brackets is large, such as the center weight 42 and the outer weight 43, the piston rod is widened in advance by the spreader 13, so that the connection work between the piston rod and the suspension bracket is extremely easy. Becomes

In the present invention, a pair of counterweight elevating hydraulic cylinders 10 suspended on the A frame shaft 3c are arranged so as not to be orthogonal to the A frame shaft 3c and not to be parallel to each other. Other configurations are not limited to the embodiments. For example, the pair of supply / discharge control valves 21 and 22 are individually operated in correspondence with the pair of counterweight elevating / lowering hydraulic cylinders 10, but one synchronous supply / discharge control valve for performing a synchronous operation and an individual for performing minute positioning operation are provided separately. Asynchronous supply and discharge control valve is provided separately,
All the valves may be opened during the synchronous operation, the supply / discharge control valve for synchronization may be opened during the minute positioning operation, and the individual asynchronous supply / discharge control valves may be individually operated.

The tube ends of a pair of counterweight lifting hydraulic cylinders are integrated with each other by one connection bracket 11 so as to be connected to the A frame shaft 3c, and the connection bracket 11 itself is not fixed to the A frame shaft 3c. However, each tube end may be connected to the A frame shaft 3c by a separate connection bracket. In this case, it is necessary to prevent the tube end of each hydraulic cylinder from sliding on the shaft due to the reaction force of the hydraulic cylinder. If the weight lifting / lowering hydraulic cylinder 10 slides, the counterweight cannot be finely operated.

[0028]

As described above, according to the present invention, the following effects can be obtained. (1) A pair of weight lifting / lowering hydraulic cylinders for connecting the pair of suspension brackets provided on the counterweight and the A frame shaft respectively at a predetermined angle that is not orthogonal to the A frame shaft and so as not to be parallel to each other. Therefore, if the hydraulic cylinders are individually extended and retracted, the counterweight can be finely moved up, down, left, and right, which facilitates fine positioning and improves workability. (2) According to the third aspect of the present invention, the pair of weight lifting / lowering hydraulic cylinders is connected to the bracket slidably provided on the A frame shaft, so that the assemblability is improved. (3) According to the invention of claim 4, the interval between the piston rods of the pair of weight lifting hydraulic cylinders is maintained at the interval between the pair of suspension brackets by the spreader. The connection work becomes easier and the workability is improved. (4) According to the fifth aspect of the present invention, since a pair of flow rate control valves for respectively controlling the flow rates of the pair of weight lifting / lowering hydraulic cylinders are provided, the piping distance between the supply / discharge control valve and the pair of weight lifting / lowering hydraulic cylinders is reduced. When the expansion and contraction speeds cannot be synchronized, the flow rate can be adjusted and easily synchronized. (5) According to the sixth aspect of the invention, fine positioning of the counterweight can be easily performed simply by operating the supply / discharge control valves individually so that the lengths of the piston rods of the pair of weight lifting / lowering hydraulic cylinders are different.

[Brief description of the drawings]

FIG. 1 is a view of an embodiment of a counterweight attaching / detaching apparatus according to the present invention as viewed from the back of a crane.

FIG. 2 is a rear view showing the entire crane of FIG. 1;

FIG. 3 is a side view of the crane of FIG. 2;

FIG. 4 is a diagram illustrating a three-piece counterweight.

5A is an assembly view of a connecting bracket, FIG. 5B is a front view of a plate material as a part thereof, and FIG. 5C is a side view thereof.

6A is a plan view of a spreader, and FIG. 6B is a front view.

FIG. 7 is a diagram showing an example of a hydraulic circuit of the counterweight attaching / detaching device of FIG. 1;

[Explanation of symbols]

 2 Upper revolving structure 3 A frame 3a Front leg 3b Rear leg 3c A frame shaft 4 Weight 7 A frame hydraulic cylinder 10 Weight lifting hydraulic cylinder 11 Connecting bracket 13 Spreader

Claims (6)

(57) [Claims] 1. A counterweight attachment / detachment device for a crane having an A-frame in which a front leg and a rear leg are connected by an A-frame shaft and which moves between a non-working posture and a working posture by expansion and contraction of an A-frame hydraulic cylinder. A pair of weight lifting / lowering hydraulic cylinders respectively connecting a pair of suspension brackets provided on the counterweight and the A frame shaft so as not to be parallel to each other at a predetermined angle that is not orthogonal to the A frame shaft; A counter weight attachment / detachment device comprising: a supply / discharge control valve for individually controlling the supply / discharge of pressure oil from a pair of weight lifting / lowering hydraulic cylinders. 2. The counterweight attaching / detaching device according to claim 1, wherein one end of each of the pair of weight lifting / lowering hydraulic cylinders is respectively connected to the A frame shaft at a central portion of the A frame shaft while restraining the movement in the axial direction. A counterweight attachment / detachment device comprising a connection bracket connected to the counterweight. 3. The counterweight attachment / detachment device according to claim 2, wherein the connection bracket is provided so as to be fitted on the A frame shaft, and the pair of bracket bodies is slidable alone on the A frame shaft. And a connecting member that integrates the pair of bracket bodies with a predetermined distance therebetween. 4. The counterweight attaching / detaching apparatus according to claim 1, further comprising a spreader for maintaining a distance between the piston rods of the pair of weight lifting / lowering hydraulic cylinders at a distance between the pair of suspension brackets. Weight attachment / detachment device. 5. The counterweight attaching / detaching apparatus according to claim 1, further comprising a pair of flow rate control valves for respectively controlling a flow rate supplied to the pair of weight lifting / lowering hydraulic cylinders via each of the supply / discharge control valves. A counterweight attaching / detaching device characterized by the above-mentioned. 6. The method for adjusting the position of the counterweight using the counterweight attachment / detachment device according to claim 1, wherein the supply / discharge control valve is arranged such that piston rods of the pair of weight lifting / lowering hydraulic cylinders have different lengths. A method for adjusting the position of a counterweight, which is operated individually.