JPS5918166Y2 - Hydraulic cylinder in structure demolition equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a hydraulic cylinder used in a structure dismantling device having a pair of movable arms for crushing structures.

As shown in FIG. 1, an example of a structure dismantling device includes a pair of rotating arms 6 having a crushing part 5 at the tip, which are rotatably connected between a pair of side plates 1 and 2 by pins 3 and 4. has 7;
Both ends of a hydraulic cylinder 9 are pivotally connected directly or indirectly (directly in the figure) between the rear ends of these rotating arms 6 and 7.

This dismantling device is attached to the tip of the boom of a construction machine such as a power shovel, and the oil inlet and outlet of the hydraulic cylinder 9 is connected to the hydraulic power source of the construction machine, and the piston rod 10 of the hydraulic cylinder is expanded and contracted. 6,7
opens and opens, and crushes the construct interlocked between the crushing parts 5.

In this case, since the demolition equipment can be attached to various construction machines, the oil supply pressure of the hydraulic source varies depending on the type of construction machine (100 kg/crf to 300 kg/am"). Therefore, the oil supply pressure to the cylinder is too high. , the moving speed of the piston rod increases, and when the piston rod extends, the piston collides with the rod-side cover, and if the pressure oil supply state is maintained even after reaching the stop position, the rod-side cover 11 There is a risk that the tightening bolt may be damaged or oil leakage may occur, and there is also a risk that the stopper 13 that regulates the closed position of the rotating arms 6, 7 may be damaged when the rotating arms 6, 7 are closed.

The present invention aims to provide a new hydraulic cylinder that can eliminate the above-mentioned drawbacks, and by forming a side passage near the piston stop position at the rod side end of the cylinder tube, the head side pressure after the piston stops is reduced. This is to prevent unnecessary pressure from being applied to the piston.

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

21 is a hydraulic cylinder, 22 is a cylinder tube, 23 is a rod side cover having an opening 24 and an oil inlet/outlet 25;
26 is a piston, 27 is a piston rod, and the rod side cover 23 is fixed to the end of the cylinder tube 22.22 via a sealing member 28 such as a gasket with, for example, four tightening bolts 29, and the opening thereof is fixed to the end of the cylinder tube 22. A piston rod 27 extends outward through 24.

Reference numeral 31 denotes a side passage with a relatively small diameter, for example, about 5 mm, which is bored in a U-shape near the piston stop position at the rod side end of the cylinder tube 22, and as is clear with reference to FIG. For example, six pieces are formed at approximately equal intervals in the circumferential direction.

At the head side position of the narrow passage 31, the piston 26 is located at the cover 23.
The head side end position of the piston 26 opens into the inner surface of the tube at the head position, and the rod side position receives oil through oil passages 32 and 33 bored at the rod side end of the piston 26. It communicates with the entrance/exit 25.

Note that the oil passages 32 and 33 of the piston 26 may be omitted, and instead, an oil passage 35 may be formed in the cover 23 as shown in chain lines.

In order to actually form the upper passage 31, a long hole 36 is bored in the axial direction from the end surface of the tube, and then a long hole 36 is drilled from the inner surface of the tube.
Holes 37 and 38 reaching 6 are bored, and a lead screw is provided at the end face of the elongated hole 36, and a blind stopper 39 is screwed into this.

Further, the hole 37 or 38 of each side passage is formed with a racer screw so that a blind stopper can be screwed into the hole 37 or 38.

Reference numeral 41 designates a plurality of metal rings, for example six metal rings, as oil seal members that are fitted onto the outer peripheral surface of the piston 26, and are designed to prevent the oil seal from being damaged under high pressure.

43 is a coil spring inserted between the rod-side cover 23 and the end face of the piston 26, and the piston 26 is supplied with pressure oil to its head side and is stopped from the state where the piston 26 is at the stop position at the rod-side end. Piston 2 when stopped
6 is retreated to a position where its outer periphery closes the hole 38 of the narrow passage 31.

According to the above-described configuration, if pressure oil is supplied while the piston 26 is on the head side, the piston 26 moves toward the rod side, the piston rod 27 extends, and the piston 26
Since the hole 38 of the narrow passage 31 communicates with the head side at or just before the position where the rod side cover 23 contacts, the pressure oil supplied to the head side through this narrow passage 31 is bypassed to the oil inlet/outlet, and therefore the cylinder tube head side pressure decreases.

In order to move the screw I-on 26 to the head side from this state, the supply of pressure oil to the head side is stopped and the oil inlet/outlet 25
It is sufficient to supply pressure oil to the

In this case, when the supply of pressure oil to the head side is stopped, the piston 26 moves slightly toward the head side by the spring 43 and closes the narrow passage 31, so that the piston 26 moves smoothly toward the head side.

As described above, according to the present invention, when the piston reaches the stop position or just before the stop position when the piston rod is extended, a bypass is formed, but unnecessary overload is not applied to the piston, and the tightening bolt is tightened. There is no risk of damage to the cylinder, oil leakage, etc., and the structure for this purpose is extremely simple since it is only necessary to form a narrow passage in the cylinder tube.

If a thread is formed in each narrow passage as in the father's example, a part of the narrow passage can be closed off with a blind plug depending on the level of supply pressure of the hydraulic power source connected to the cylinder. It is possible to connect to a hydraulic source of supply pressure.

Since the oil passage in the present invention is formed inside the cylinder tube rather than outside the cylinder tube, it has the advantage of not being damaged from the outside.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view showing an example of a structure dismantling device, and FIGS. 2 and 3 are a longitudinal sectional view and a transverse sectional view showing an example of the proposed device. 21 is a hydraulic cylinder, 22 is a cylinder tube, 23 is a rod side cover, 26 is a piston, 27 is a piston rod, 31 is a narrow passage, and 43 is a spring.

Claims (2)

[Scope of utility model registration request] (1) In a structure dismantling device having a pair of movable arms for crushing a structure, a hydraulic cylinder is disposed between the pair of movable arms to relatively move them, and the hydraulic cylinder is connected to its cylinder tube. A hydraulic cylinder for a structure dismantling apparatus, in which an oil passage is formed at a piston stopping position on the rod side of the piston, the oil passage opening slightly outward from both end surfaces of the piston and penetrating the inside of the cylinder tube. (2) The hydraulic cylinder according to claim 1, wherein a spring wound around the piston rod is disposed between the rod-side cover of the hydraulic cylinder and the piston.