JPH0632985Y2 - Stroke suppression device for long hydraulic cylinder for supporting leader in pile driver etc. - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to the stroke of a long hydraulic cylinder used as a back stay for supporting a leader in a construction machine such as a pile driver so that the leader can be raised and lowered. It relates to a device for limiting a certain short working range.

(Prior art and its problems) In a pile driving machine, a leader for supporting a press-fitting machine or the like to move up and down is supported by a crawler crane or the like so that it can be undulated via a long hydraulic cylinder as a back stay. And this back stay cylinder,
When the leader is moved from a substantially horizontal non-working posture as shown in FIG. 2 to a standing working posture as shown in FIG. 1, the cylinder overall length greatly expands, and a correspondingly long stroke is required. However, such a long stroke is required only when assembling and disassembling the machine, and during the actual pile driving work, the standing leader can be adjusted to a slightly forward or backward tilt angle. Stroke, for example 1/5 to 1/6 of the total cylinder stroke
Stroke is enough.

However, in the conventional pile driving machine, since the means for suppressing the operation stroke of the back stay cylinder to a certain short stroke as described above at the time of the pile driving work is not taken, the angle adjustment of the leader is performed. At that time, there was a risk that the leader could be accidentally tilted to extend or retract the cylinder.

The present invention has been made in view of the above circumstances.

(Means for Solving Problems) The present invention selects a head side chamber and a rod side chamber of a long hydraulic cylinder for supporting a leader, which supports a leader of a pile driver etc., in a undulating manner, as a hydraulic pressure source or a tank, respectively. The head side chamber and the switching valve, and the rod side chamber and the switching valve and the rod side connecting line, respectively, flow freely toward the long hydraulic cylinder side. A pilot-type or counterbalance-type check valve to be provided, and between the check valve and the switching valve in either one of the connection lines,
A stroke limiting hydraulic cylinder for limiting the stroke of the long hydraulic cylinder to a certain small range is provided, with one side chamber communicating with the check valve side across the piston and the other side chamber communicating with the switching valve side. The present invention is to provide a stroke suppressing device having a stop valve provided in the detour of the above.

(Embodiment) An embodiment of the present invention will be described with reference to the drawings. In FIGS. 1 and 2, reference numeral 1 is a leader of a pile driving machine equipped with a press-fitting machine A and an auger machine B so as to be able to move up and down. 1 is a crawler crane 2 for supporting arm 3 and back stay cylinder (long hydraulic cylinder for supporting leader) 4
It is supported via up and down freely. A tip portion of a cylinder tube 5 of the back stay cylinder 4 is pivotally attached to the leader 1, and a tip portion of a rod 7 connected to a piston 6 sliding in the cylinder tube 5 is pivotally attached to the crawler crane 2.

FIG. 3 shows the maximum stroke S _{m of the} backstay cylinder 4.
Is about 1/5 to 1/6 of this, and the hydraulic circuit of the device for suppressing the small stroke s required for the actual pile driving work is shown. Head-side supply / discharge port 9 communicating with the head-side chamber 8 and rod-side supply / discharge port 11 communicating with the rod-side chamber 10.
Is the head side connecting line 12 and the rod side connecting line 1
Connected to the 3-position switching valve 14 via 3 respectively,
The head-side connecting line 12 and the rod-side connecting line 13 have a free flow toward the supply / exhaust ports 9 and 11, respectively, and the pilot pressure liquid introducing passages 16a and 15a from the connecting lines 13 and 12 which are opposite to each other. Check valves 15 and 16 with pilots, which can receive the supply of pilot pressure via the respective valves, are provided. Further, in the head side connection line 12, between the check valve 15 and the switching valve 14, a stroke that reciprocates within the range of the small stroke s to limit the maximum stroke S _m of the backstay cylinder 4 to the small stroke s. A control hydraulic cylinder 17 is provided, and a supply / discharge port 2 that communicates with one side chamber 19 of the cylinder 18 with the piston 18 interposed therebetween.
0 is the switching valve side, and the supply / discharge port 22 communicating with the other side chamber 21.
Respectively communicate with the check valve 15 side, and further bypass the stroke limiting hydraulic cylinder 17 to switch the switching valve 14
Side and the check valve 15 side bypass line 1 directly leading to
2a (detour) is provided, and this bypass line 1
A stop valve 23 is provided at 2a. A coil spring 24 is provided in the stroke limiting hydraulic cylinder 17 for holding the piston 18 at the position shown by the solid line in FIG. 3 at all times. Further, a hydraulic pump 25 and a tank 26 are connected to the switching valve 14, and these pump 25 and tank 2 are connected.
6 is selectively connected to the head side connection line 12 or the rod side connection line 13 by the switching valve 14.

Incidentally, instead of the check valves 15 and 16 with the pilot,
Check valves each with a counter balance circuit,
For example, a check valve may be provided so that when the fluid pressure acting on the valve in the fluid flow blocking direction reaches or exceeds a certain fixed pressure, the fluid flow blocking is released to allow a free flow.

Next, the operation of the stroke suppressing device having the above-described structure will be described with reference to FIGS.

FIG. 2 shows the pile driver in a non-working posture with the leader 1 lying down in a substantially horizontal state. At this time, the piston rod 7 of the backstay cylinder 4 contracts to the maximum extent, and the piston 6 thereof moves to the first position. Maximum stroke S in the circuit diagram of Fig. 3
_It is located at the right end of _m , and the length of the backstay cylinder at this time is l _o as shown in FIG.

Then, when starting the pile driving work, in order to raise the leader 1 from the horizontal laid posture of FIG. 2, first, the stop valve 23 is opened and the switching valve 14 is switched to the position (a). Then, the pressure liquid from the hydraulic pump 25 enters the head side connecting Rahain 12 via the pump discharge side line 27 and the switching valve 14, and then reaches the check valve 15 side through the bypass line 12a. At this time, the pressure liquid flows into the both side chambers 19 and 21 of the stroke limiting cylinder 17 at a constant pressure, so that the piston 18 remains held at the position shown by the solid line in FIG. The pressure liquid from the bypass line 12a passes through the check valve 15 and flows into the head side chamber 8 from the head side supply / discharge port 9 of the backstay cylinder 4, whereby the piston rod 7 is extended and the leader 1 is moved to the position shown in FIG. Shifts from the horizontal lying position to the standing position. The pressure liquid in the rod-side chamber 10 of the backstay cylinder 4 is sent out from the rod-side supply / discharge port 11 to the rod-side connection line 13, and in the check valve 16, is supplied from the head-side connection line 12 through the pilot pressure liquid introduction passage 15a. The check valve 16 is opened by the pilot pressure
Therefore, the pressurized liquid passes through the rod side connection line 13, and is returned from the switching valve 14 to the tank 26 via the tank side line 28.

In the actual pile driving work, the leader 1 has a vertically standing posture as a main working posture as shown in FIG. _{1, and a} rearward tilted posture inclined by an angle α ₁ and a forward inclined posture by an angle α _{2 from this.} The angle is adjusted between the forward leaning posture.
It should be noted that the axis line passing through the pivot point O of the support arm 3 supporting the leader 1 and the pivot point P of the backstay cylinder 4 in the vertical posture is m _2, and the similar axes in the backward tilted posture and the forward tilted posture. Let m ₁ and m ₃ , respectively. Therefore, as described above, while the pressurized liquid is introduced into the head side chamber 8 of the backstay cylinder 4 to extend the length of the cylinder 4, the leader 1 is placed in the backward tilted posture of the axis l ₁ as shown in FIG. When it is raised up to this point (the cylinder length in the tilted position is indicated by l ₁ in the figure), the stop valve 23 is closed. By closing the stop valve 23, the pressure fluid pump 2
Since the bypass line 23 is cut off, the hydraulic fluid flowing from the head 5 to the head side connecting line 12 flows into the one side chamber 19 of the stroke limiting hydraulic cylinder 17 to push the piston 18 at the right end position of the stroke. The pressure liquid in the other side chamber 21 of the cylinder 17 is moved by the check valve 1
5 is sent to the head side chamber 8 of the backstay cylinder 4, and the piston 6 is further pushed from the position corresponding to the rear posture of the leader shown by the solid line in FIG. 3 to extend the piston rod 7. Then, when the piston 18 of the stroke limiting hydraulic cylinder 17 comes to the intermediate position of the stroke as shown by the one-dot chain line in FIG. 3, the piston 6 of the backstay cylinder 4 is correspondingly shown in FIG. It moves to the position shown by the one-dot chain line, the length of the backstay cylinder 4 at this time is l ₂ as shown in FIG. 1, and the leader 1 is in a vertical posture with its axis located at m ₂ . When the piston 18 of the stroke limiting hydraulic cylinder 4 further reaches the left end position of the stroke as shown by the two-dot chain line, the piston 6 of the backstay cylinder 4 is also located at the left end of the stroke as shown by the two-dot chain line. At this time, the back stay cylinder 4 has the maximum l ₃ , and the leader 1 is in the forward tilted posture in which the axis is located at m ₃ , and does not tilt forward from that.

Also, with the stop valve 23 closed, the switching valve 14
When the position of (a) is switched to the position of (c), the hydraulic pump 25
The pressure liquid from the above enters the rod side connection line 13 via the pump discharge side line 27 and the switching valve 14, passes through the check valve 16 and the rod side supply / discharge port 1 of the backstay cylinder 4.
1 into the rod side chamber 10 and pushes the piston 6 to the right in FIG. 3 to contract the piston rod 7. By the pushing of the piston 6, the pressure liquid in the head side chamber 8 is sent out from the head side supply / discharge port 9 to the head side connecting line 12, and in the check valve 15, from the rod side connecting line 13 through the pilot pressure liquid introducing passage 16a. The check valve 15 is opened by the supplied pilot pressure. Therefore, the pressure liquid passing through the check valve 15 is supplied to the chamber 21 of the stroke limiting hydraulic cylinder 17 to push the piston 18 thereof to the right in FIG. Move. The movement of the piston 18 is restricted at the right end position of the stroke indicated by the solid line in FIG.
The piston 6 is also restricted in movement at the position shown by the solid line corresponding to the piston position of the stroke limiting hydraulic cylinder 17, so that this backstay cylinder 4 does not shrink below the length of l ₁ , and the leader 1 The axis m _{1 is in} a rearwardly tilted posture, and does not tilt rearwardly.

As described above, when the leader 1 is stood up to the rearward tilted posture of the axis m ₁ and then the stop valve 14 is closed, the back stay cylinder 4 is moved by the stroke limiting hydraulic cylinder 17.
Is restricted, and the tilting range of the leader 1 is suppressed to the tilting range required for the actual pile driving work from the backward tilted position of the axis m _{1 to} the forward tilted posture of the axis m ₃ . Switch valve 14
When the reader 1 is set to the position (b), the reader 1 is held in the required standing posture.

(Operation and Effect of the Invention) According to the stroke suppressing device of the present invention, when the leader is moved from the lying posture to the standing posture, the stroke limiting hydraulic cylinder and the stop valve are provided on the head side connecting line, for example. , First, by opening the stop valve, the pressure fluid from the fluid pressure source enters the head side connection line from the switching valve, passes through the bypass line where the stop valve is provided, and passes through one check valve and the leader. It flows into the head side chamber of the supporting long hydraulic cylinder. At this time, since the same hydraulic pressure acts on both side chambers of the piston in the stroke limiting hydraulic cylinder, the piston does not move. Then, the piston is pushed by the pressure liquid that has flowed into the head side chamber of the long hydraulic cylinder and the piston rod extends, which causes the leader to rise, while the pressure liquid in the rod side chamber moves toward the rod side. If the check valve is discharged to the connection line, and this check valve is, for example, a pilot type check valve, it is opened by receiving pilot pressure from the head side connection line, and the pressure fluid passes through the check valve. , It is returned to the tank via the switching valve.

When the leader stands up to the lower limit posture (for example, the forward leaning posture) of the constant working range limited by the stroke limiting hydraulic cylinder, the stop valve is closed. When pressure liquid is further supplied to the rod side chamber of the long hydraulic cylinder from the state where the leader is in its lower limit work posture, the piston is pushed,
The piston rod extends to the maximum stroke end of this cylinder, and the leader is in the upper limit posture (for example, the forward leaning posture).
Then, when the position of the switching valve is switched so that the pressure liquid from the hydraulic pressure source flows in the rod side connection line in the opposite manner to the above, the pressure liquid passes through the check valve of this line from this rod side connection line. Flow into the rod side chamber of the long hydraulic cylinder, and push its piston in the opposite direction to the above,
As a result, the pressure liquid in the head side chamber is discharged to the head side connection line, passes through the check valve on the line in the same manner as in the above case, flows into the chamber on one side of the stroke limiting hydraulic cylinder, and the piston As a result of pushing, the pressure liquid in the other chamber is discharged from the cylinder and returned to the tank through the switching valve. In this way, when the stroke limiting hydraulic piston is pushed to its stroke end and its movement is stopped, the movement of the piston of the long hydraulic cylinder is correspondingly limited, which limits the contraction of the piston rod. Therefore, the tilting of the leader is held at the lower limit position.

As described above, according to the present invention, the maximum stroke of the long hydraulic cylinder for supporting the leader can be suppressed to a constant short stroke necessary for the work by the action of the stroke limiting hydraulic cylinder by operating the stop valve. It is possible to avoid a dangerous situation in which the reader is tilted due to an erroneous cylinder expansion / contraction operation while adjusting the angle of.

[Brief description of drawings]

FIG. 1 is a side view of a pile driver showing an embodiment of the present invention.
FIG. 2 shows a state in which the leader is in a standing posture, and FIG. 2 is a side view of the pile driver in which the leader is in a horizontal lying posture.
The figure is a hydraulic circuit diagram of the stroke suppressing device. 1 ... Leader, 4 ... Back stay cylinder (long hydraulic cylinder for supporting leader), 6 ... Piston, 7 ... Piston rod, 8 ... Head side chamber, 10 ... Rod side chamber,
12 ... Head side connection line, 13 ... Rod side connection line, 14 ... Changeover valve, 15, 16 ... Pilot check valve, 17 ... Stroke limiting hydraulic cylinder, 2
3 ... Stop valve, 25 ... Hydraulic pump (hydraulic pressure source), 2
6 ... Tank.

Claims (1)

[Scope of utility model registration request] 1. A head-side chamber and a rod-side chamber of a long hydraulic cylinder for supporting a leader, which supports a leader of a pile driver etc. in an up-and-down manner, are connected to a switching valve for selectively connecting to a hydraulic pressure source or a tank, respectively. , The head side connecting line between the head side chamber and the switching valve and the rod side connecting line between the rod side chamber and the switching valve have a pilot type or counterbalance type check that allows free flow toward the long hydraulic cylinder side. A valve is provided, and in one of the connection lines of the both connection lines, between the check valve and the switching valve, a piston is sandwiched between the one side chamber and the check valve side,
A pile driving machine in which the other side chamber communicates with the switching valve side and is provided with a stroke limiting hydraulic cylinder that limits the stroke of the long hydraulic cylinder to a certain small range, and a stop valve is provided in the bypass of the cylinder. Stroke suppression device for long hydraulic cylinders for supporting leaders in etc.