JPH0859184A - Device for attaching/detaching counter weight and method for adjusting position of counter weight - Google Patents

Abstract

PURPOSE: To provide a counter weight attaching/detaching device capable of improving the operability of attachment/detachment of a counter weight, and reducing the time for attachment/detachment. CONSTITUTION: A counter weight attaching/detaching device is used for a crane provided with an A-frame 3 where a forward leg is connected to a rear leg by an A-frame shaft 3c, and which is moved by an A-frame hydraulic cylinder 7 between the non-working position and the working position. The counter weight attaching/detaching device is provided with a pair of weight elevating hydraulic cylinders 10 to respectively connect a pair of suspension brackets 43 which are provided on the counter weight at the prescribed angle not orthogonal to the A-frame shaft 3c and not in parallel to each other to the A-frame shaft 3c, and a pair of charge/discharge control valves to individually control the charge/discharge of the pressurized oil in a pair of elevating hydraulic cylinders 10.

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 device for easily attaching / detaching a counterweight of a mobile crane.

[0002]

2. Description of the Related Art Conventionally, various devices for attaching and detaching counterweights of mobile cranes have been developed. For example, in the device disclosed in Japanese Utility Model Laid-Open No. 5-82982, a gantry cylinder for operating the A frame up and down,
It is provided with two counter cylinders suspended from an A frame shaft connecting the front and rear legs of the A frame. The gantry cylinder is expanded and contracted while the distance between the counterweight and the A-frame axis is set appropriately by the counter cylinder, and the counterweight is moved along an appropriate movement path to avoid interference between the counterweight and the main frame. Weights are attached and removed.

[0003]

When fastening the counterweight to the body frame with bolts, it is necessary to adjust the counterweight in the vertical direction as well as in the horizontal direction. However, in this conventional device, in order to adjust the vertical and horizontal positions, the only way to adjust the counterweight is by twisting the counterweight with a device such as a bar. There are problems that the operability is not improved so much and that the time required for attachment / detachment is not shortened so much.

An object of the present invention is to provide a counterweight attaching / detaching device which can improve the operability of attaching / detaching the counterweight and shorten the attaching / detaching time.

[0005]

1 and 7 showing an embodiment, the present invention will be described. In the present invention, the front leg 3a and the rear leg 3b are connected by an A frame shaft 3c, and a non-working posture is provided. The present invention is applied to a counterweight attaching / detaching device of a crane equipped with an A frame 3 that moves between a work posture and an A frame hydraulic cylinder 7 by expanding and contracting. Then, the above-mentioned purpose is to prevent the counterweights (41, 4) from being parallel to each other at a predetermined angle which is not orthogonal to the A frame axis 3c.
2, 43) a pair of hanging brackets (41
a, 42a, 43a) and the A-frame shaft 3c, respectively, and a pair of weight lifting hydraulic cylinders 10, and supply / discharge control valves 21, 22 for individually controlling the supply / discharge of pressure oil of the pair of lifting hydraulic cylinders 10. It is achieved by including and. The weight attaching / detaching device according to claim 2 is a connecting bracket 1 for connecting one end of each of the pair of weight lifting hydraulic cylinders 10 to the A frame shaft 3c in the central portion of the A frame shaft 3c while restraining the movement in the axial direction.
1 is provided. The connecting bracket 1
5, a pair of bracket main bodies 11a that are provided by being fitted to the A frame shaft 3c and are slidable on the A frame shaft 3c alone, and a pair of the bracket main bodies 11a are predetermined. The connecting members 11b and 11c can be integrated with each other at a distance of. Claim 4
The weight attaching / detaching device is characterized by including a spreader 13 that holds the distance between the piston rods of the pair of weight lifting hydraulic cylinders 10 at the distance between the pair of suspension brackets (42a, 43a). As shown in FIG. 7, the weight attaching / detaching device of the fifth aspect of the present invention includes a supply / discharge control valve 21,
A pair of weight lifting hydraulic cylinders 1 through 22
A pair of flow rate adjusting valves 25 and 26 for adjusting the flow rates respectively supplied to 0 are provided. 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 of the first aspect, the feed / discharge control valves 21, 22 are arranged so that the lengths of the piston rods of the pair of weight lifting hydraulic cylinders 10 are different. Is operated individually.

[0006]

When the pair of hydraulic cylinders 10 are individually expanded and contracted, the counterweights (41, 42, 43) finely move up, down, left and right, so that delicate positioning can be performed. The connecting bracket 11 of claim 3 is not fixed to the A frame shaft 3c, but the reaction force of the pair of hydraulic cylinders 10 is received from the left and right, and the mounting position does not move. The spreader 13 holds the distance between the piston rods of the pair of weight lifting hydraulic cylinders 10 at the distance between the pair of suspension brackets (42a, 43a). The flow rate control valves 25, so that the operations of the respective hydraulic cylinders 10 can be synchronized.
Adjust the flow rate at 26.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the counterweight attaching / detaching device according to the present invention is applied to a self-propelled crawler crane will be described below with reference to FIGS. 2 and 3, the 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 the front of the upper swing body 2, an A frame 3 that supports the crane boom with a hoisting rope, and a counter that is detachably provided at the rear end of the upper swing body 2. And a weight 4.

As shown in FIG. 4, the counterweight 4 is composed of 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 of a bolt for attaching the inner weight itself to the upper swing body 2 is provided.
And a screw hole 41c for mounting the center weight 42, a screw hole 41d for mounting the center weight and the outer weight, and a through hole for fixing the three weights together to the upper swing body 2. Hole 41
e and are 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,
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 intervals as the center weight 42, and through holes 43e for bolts corresponding to the holes 41e for collectively attaching three weights to the upper swing body 2. And a through hole 43d for a bolt for attaching the outer weight 43 to the inner weight 41 together with the center weight 42.

1 to 4, the A frame 3 includes a pair of left and right front legs 3a, a pair of left and right rear legs 3b, and front and rear legs 3.
It is composed of an A frame shaft 3c rotatably connecting a and 3b at their upper ends. 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 extendable and retractable, and the lower end of the lower component thereof is at the upper revolving structure frame 2
It is rotatably connected to a bracket (not shown) provided on the rear side by a rear leg connecting pin. As is well known, the sheave 5 and the A frame hanger 6 are provided on the A frame shaft 3c, and the boom hoisting rope from the boom hoisting winch mounted on the main body frame 2 is provided with a plurality of sheaves 5 to 6 in the A frame hanger 6. It is routed between a 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 in the center of the A-frame shaft 3c between the A-frame 3 and the upper revolving structure 2, and the extension of the hydraulic cylinder 7 causes the A-frame 3 to move its front leg 3a.
3 is moved up and down from the non-working posture P3 of FIG. 3 through the intermediate posture P2 to the working posture P1. Also,
By the contraction of the hydraulic cylinder 7, the reverse operation is performed.

In FIGS. 1 and 2, reference numeral 10 is a weight lifting hydraulic cylinder which constitutes a counterweight attaching / detaching device, and is suspended by a bracket 11 at the center of the A frame shaft 3c. As shown in detail in FIG. 5, the bracket 11 is fixed to a pair of left and right fan-shaped plates 11a, a bolt 11c connecting the pair of plates 11a through a spacer 11b, and fixed to the 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 penetrates the hole 11e formed in the central portion of the plate 11a. The projection 11f provided on the inner surface of the plate 11a is used for positioning the A-frame lifting hydraulic cylinder 7.

The tube ends of the counterweight lifting hydraulic cylinders 10 are connected to the hydraulic cylinder mounting brackets 11d, respectively. A counter weight connecting link 12 (FIG. 1) is connected to the piston rod ends of the pair of hydraulic cylinders 10 by a pin, and a spreader 13 is interposed between the brackets 12 to connect the pistons of the pair of hydraulic cylinders 10. Increase the distance between the rods.

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

That is, unless the distance between the piston rods is widened by the spreader 13, when connecting each piston rod end to the center weight 42 and the outer weight 43, an operator uses the counterweight to push the piston rod end of the hydraulic cylinder 10. It has to be moved to the left and right up to the width of the hanging bracket, which is a heavy work. Therefore, the interval is widened in advance by the spreader 13.

FIG. 7 is a hydraulic circuit diagram of the counterweight attaching / detaching device. 21 to 23 are supply / discharge control valves for adjusting the supply amount of the pressure oil to the counterweight lifting hydraulic cylinder 10 and the A-frame hydraulic cylinder 7, respectively, and 24 is a hydraulic pump.
25 to 27 are flow rate adjusting valves that adjust the amount of oil flowing from the hydraulic pump 24 to each hydraulic cylinder to adjust the expansion and contraction speed of each hydraulic cylinder, and 28 and 29 extend the piston rod of the counterweight lifting hydraulic cylinder 10. A balancing valve 30 that opens to allow the discharge of oil when pressure oil flows in a direction, and a balancing valve 30 that opens to allow discharge of oil when pressure oil flows in a direction that contracts the piston rod of the A-frame hydraulic cylinder 7. It is a valve.

The operation of suspending the outer weight 43 with the counterweight attaching / detaching device thus constructed will be described with reference to FIG. The inner weight 41 and the center weight 42 will be described as being attached first. The self-propelled crane is moved with the A frame 3 folded, and the axial center of the A frame shaft 3c and the position of the suspension bracket 43a of the outer weight 43 are aligned. The spreader 13 attached at the time of attaching the center weight 42 is left as it is, and the feed / discharge control valves 21 and 22 are simultaneously operated to the lower side to extend the weight lifting hydraulic cylinder 10 to connect the connecting link 12 to the hanging 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 to 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 the weight 43 to the upper swing body 2 side while suspending the weight 43. 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,
The hydraulic cylinder 1 for lifting and lowering the weight by simultaneously lowering 22
0 is extended, and the outer weight 43 is lowered to the connection position with the center weight 42. The feed / discharge control valves 21 and 22 are individually operated to extend and contract the pair of left and right weight lifting hydraulic cylinders 10 to align the weight mounting through holes 43b with the corresponding through holes of the center weight 42. The outer weight 43 is attached to the upper revolving structure 2 with a bolt through the center weight 42 and the inner weight 41.

When attaching the inner weight, the hanging bracket 41a of the inner weight 41 is attached.
Is narrower than the outer weight 43. Therefore, it is necessary to remove the spreader 13. Moreover, since the height position of the suspension bracket 41a is low, a separately prepared connecting link is required between the weight lifting hydraulic cylinder 10 and the suspension bracket 41a.

The procedure for removing the weight is the reverse of the procedure for attaching, and the 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 wire rope for fixing.

The above embodiment has the following 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
The distance from c is shortened to a predetermined distance, and thereafter, the weight is lifted by the A-frame hydraulic cylinder 7 so as to approach the upper revolving structure 2, so that the weight does not collide with the weight mounting portion of the upper revolving structure 2. It can be suspended above it.

The tube ends of the pair of weight lifting hydraulic cylinders 10 are integrally attached to the central portions of the A frame shafts 3c by the brackets 11, respectively, so that the hydraulic cylinders 10 are not orthogonal to the A frame shafts 3c but have a predetermined angle (see FIG. 1). Since it is designed to be suspended and can be operated individually, the weight can be finely adjusted to the left and right and up and down by individually adjusting the expansion and contraction amount of each of the counterweight lifting hydraulic cylinders 10. This makes it extremely easy to position the mounting holes. When a pair of weight lifting hydraulic cylinders 10 are arranged orthogonally to the A frame shaft 3c, as in the counterweight attaching / detaching device disclosed in Japanese Utility Model Laid-Open No. 5-82982, which is described in the conventional example, , Even if each of them can be individually expanded and contracted, it is difficult to finely operate the counterweight left and right.

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

When the supply / discharge control valves 21, 22 and the weight lifting hydraulic cylinders 10 have different piping distances, the expansion / contraction speeds of the hydraulic cylinders cannot be synchronized when the supply / discharge control valves 21, 22 are simultaneously operated. There is a supply / discharge control valve 2
1, 22 and the hydraulic cylinder 10 between the flow rate adjusting valve 25,
Since 26 is provided and the amount of oil supplied to each hydraulic cylinder can be adjusted, the pair of hydraulic cylinders 10 can be accurately synchronized.

When the distance between the hanging brackets is wide like the center weight 42 and the outer weight 43, the spreader 13 is used to widen the space between the piston rods in advance, so that the connecting work between the piston rods and the hanging bracket is extremely easy. Becomes

According to the present invention, the pair of counterweight lifting hydraulic cylinders 10 suspended by the A frame shaft 3c are arranged so as not to be orthogonal to the A frame shaft 3c and not parallel to each other. However, other configurations are not limited to the embodiments. For example, the pair of supply / discharge control valves 21 and 22 are individually operated in association with the pair of counterweight lifting hydraulic cylinders 10. However, one synchronous supply / discharge control valve to be operated synchronously and an individual fine positioning operation to be operated separately. Asynchronous supply / discharge control valve is provided separately,
You may make it open all the valves at the time of a synchronous operation, open a supply / discharge control valve for synchronization at the time of a minute positioning operation, and operate an individual asynchronous supply / discharge control valve individually.

Further, the tube ends of the pair of counterweight lifting hydraulic cylinders are integrated with each other by one connecting bracket 11 so as to be connected to the A frame shaft 3c, and the connecting 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 connecting 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 hydraulic cylinder 10 slides due to the reaction force, the counterweight cannot be finely operated.

[0028]

As described in detail above, according to the present invention, the following effects can be obtained. (1) Provide a pair of weight lifting hydraulic cylinders that respectively connect the pair of suspension brackets provided on the counterweight and the A frame axis at a predetermined angle not orthogonal to the A frame axis and so as not to be parallel to each other. Therefore, if the hydraulic cylinders are individually expanded and contracted, the counterweight can be finely moved up and down, and left and right, which facilitates delicate positioning and improves workability. (2) According to the invention of claim 3, since the pair of weight lifting hydraulic cylinders are connected to the bracket slidably provided on the A frame shaft, the assembling property is improved. (3) According to the invention of claim 4, the distance between the piston rods of the pair of weight lifting hydraulic cylinders is held at the distance between the pair of suspension brackets by the spreader. Connection work becomes easier and its workability improves. (4) According to the invention of claim 5, since the pair of flow rate adjusting valves for adjusting the flow rates of the pair of weight lifting hydraulic cylinders are provided, the piping distance between the supply / discharge control valve and the pair of weight lifting hydraulic cylinders is reduced. When the expansion and contraction speeds cannot be synchronized by difference, the flow rate can be adjusted and easily synchronized. (5) According to the invention of claim 6, the minute positioning of the counterweight can be easily performed only by individually operating the supply and discharge control valves so that the piston rods of the pair of weight lifting hydraulic cylinders have different lengths.

[Brief description of drawings]

FIG. 1 is a view of an embodiment of a counterweight attaching / detaching device according to the present invention as seen from the rear of a crane.

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

3 is a side view of the crane of FIG.

FIG. 4 is a diagram for explaining a counterweight having a three-piece structure.

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

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

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

[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)

[Claims] 1. A counterweight attaching / detaching device for a crane comprising 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 extension and contraction of an A-frame hydraulic cylinder, A pair of weight lifting hydraulic cylinders that respectively connect the pair of suspension brackets provided on the counterweight and the A frame axis at a predetermined angle that is not orthogonal to the A frame axis and are not parallel to each other; A counterweight attaching / detaching device comprising: a supply / discharge control valve for individually controlling the supply / discharge of pressure oil from a pair of weight lifting hydraulic cylinders. 2. The counterweight attachment / detachment device according to claim 1, wherein one end of each of the pair of weight lifting hydraulic cylinders is attached to the A frame shaft at a central portion of the A frame shaft while restraining movement in the axial direction. A counterweight attaching / detaching device comprising a connecting bracket for connecting to the counterweight. 3. The counterweight attaching / detaching device according to claim 2, wherein the connecting bracket is provided by being fitted to the A frame shaft, and a pair of bracket main bodies which are slidable on the A frame shaft by themselves. A counterweight attaching / detaching device, comprising: a connecting member that integrates the pair of bracket main bodies by a predetermined distance. 4. The counterweight attaching / detaching device according to claim 1, further comprising a spreader for holding the distance between the piston rods of the pair of weight lifting hydraulic cylinders at the distance between the pair of suspension brackets. Weight attaching / detaching device. 5. The counterweight attaching / detaching device according to claim 1, further comprising a pair of flow rate adjusting valves for adjusting flow rates respectively supplied to a pair of weight lifting hydraulic cylinders via each of the supply / discharge control valves. Counterweight attachment / detachment device characterized by: 6. The method for adjusting the position of the counterweight using the counterweight attaching / detaching device according to claim 1, wherein the feed / discharge control valve is configured such that the piston rods of the pair of weight lifting hydraulic cylinders have different lengths. A counterweight position adjusting method characterized by being operated individually.