JPH0581689B2 - - Google Patents

Description

[Detailed description of the invention]

【0001】

TECHNICAL FIELD The present invention relates to a back tension device for a three-point support type pile driver.

【0002】

[Prior Art] As shown in FIG. 4, a three-point support type pile driver 1 has a front bracket 3 at the front of a main body 2.
The lower part of the leader 4 is pivotally supported on the front bracket 3, and the upper part of the leader 4 is attached to the front bracket 3.
It is supported on the main body 2 by a book backstay 5. Auger wire rope 7 pulled out from the winch drum (not shown) of main body 2 via pulley 6
The sheave 9 of the top sheave block 8 fixed to the upper end of the leader 4 and the sheave 12 of the auger 11 equipped with the screw 10 are hooked in several threads, and the end 7a is pivoted to the top sheave block 8. There is.

[0003] Furthermore, the three-point support type pile driver 1 is shown in FIG.
As shown in A and B, the auger 11 and the hammer 13 are suspended from the leader 4, and the leader 4 is rotated approximately 90 degrees using a rotating device (not shown).
A double-sided rotary type that drives piles using a combination of
As shown in A and B, an auger 11 is installed in front of the leader 4.
Alternatively, there is an end-fixed type in which a hammer 13 or a drop auger (not shown) is suspended to drive a pile, and this work is usually performed on the front side of the main body 2.

[0004] In these pile driving operations, especially in auger operations, a large force is applied to the leader 4 during screw propulsion due to the rotation of the auger during excavation and when the screw is pulled out after excavation, which acts as bending stress on the leader 4. Therefore, auger work is restricted.

[0005] To solve this problem, if a bending stress commensurate with the load on the auger side is generated from the center of the leader 4 to the opposite side of the auger 11, only compressive force will act on the leader 4, so the auger work will be easier. capacity can be increased.

[0006] The device used for this is a back tension device, and there are various devices. The rope passes through the sheave of a top sheave block installed at the top of the rotating leader, and the other end is connected to the rod of a double-acting hydraulic cylinder supported by the front bracket, and an electromagnetic switching valve is connected to the operating circuit of the double-acting hydraulic cylinder. There is a structure in which the electromagnetic switching valve is switched as the leader rotates, tensioning the rope during auger work and loosening the rope during hammer work.

【0007】

[Problems to be Solved by the Invention] However, the above-mentioned device simply replaces the conventionally used turnbuckle with a double-acting hydraulic cylinder, and is used to correct slack in the back tension wire rope during auger work. In addition, it is necessary to insert a manual switching valve in series on the upstream side of the electromagnetic switching valve into the operating circuit of the double-acting hydraulic cylinder, and to correct the tension of the rope by operating the manual switching valve each time. Since this correction is frequently performed during auger operation, it is extremely troublesome for the driver to operate it, and furthermore, it may cause damage to the leader due to incorrect operation, so an improvement has been desired.

[0008] The present invention was made in view of the above points, and eliminates the trouble of manually correcting the tension of the tension rope and the risk of incorrect operation, and provides a three-point support type pile driving system with high operability and safety. The purpose is to provide a back tension device for the machine.

【0009】

[Means for Solving the Problems] In order to achieve the above-mentioned object, the first invention provides a top sheave block that is fixed to the upper end of the leader of a three-point support type pile driver. One end of the tension wire rope is connected, the other end is connected via a hydraulic cylinder to the front bracket supporting the leader, and the end of the auger wire rope is pivotally connected to the top sheave block via a load pressure gauge. An electric switching valve and a relief valve are provided in parallel in the operating circuit of the hydraulic cylinder, and a contact point of the load pressure gauge is provided in the electrical circuit of the electromagnetic switching valve, so that the electromagnetic switching is performed by the operation of the load pressure gauge. This device is characterized in that the back tension wire rope is tensioned by switching the valve.

[0010] In addition, the second invention connects one end of the back tension wire rope to the back side of the auger of the top sheave block fixed to the upper end of the leader of the three-point support type pile driver, and connects the other end to the hydraulic cylinder. The end of the auger wire rope is pivotally connected to the top sheave block via a load voltmeter, and an electromagnetic proportional relief valve is provided in the operating circuit of the hydraulic cylinder. In addition, a converter for converting the output voltage of the load voltmeter into a current value is provided in the electrical circuit of the electromagnetic proportional relief valve, and the output of the load voltmeter controls the electromagnetic proportional relief valve to provide back tension. It is characterized by being constructed so that a wire rope can be stretched thereon.

【0011】

[Function] Therefore, in the first invention, the leader is an electromagnetic proportional relief valve based on the backward bending stress corresponding to the set pressure of the relief valve, and in the second invention, the leader is an electromagnetic proportional relief valve based on the signal from the load voltmeter. A backward bending stress corresponding to the relief pressure of is applied respectively.

【0012】

[Embodiment] An embodiment of the present invention will be described in detail based on FIGS. 1 to 3. In the drawings, the same reference numerals as in FIGS. 4 to 6 indicate the same elements.

[0013] First, regarding the first invention, FIGS. 1 and 2
To explain, as shown in FIG. 1, the lower part of the leader 4 is pivotally supported by the front bracket 3, and the top sheave block 8 is fixed to the upper part of the leader 4.
Several ends 7a of a wire rope 7 for the auger are hooked onto the top sheave block 8 and are pivotally connected to the sheave 9 and the sheave 12 of the auger 11.

[0014] The end 7a is also provided with a load pressure gauge 21 that turns a pressure switch 21a ON and OFF according to a set load.

[0015] A bracket 22 is fixedly installed on the back side of the auger of the top sheave block 8, and a back tension wire rope 23 is attached to the bracket 22.
One end is connected by a pin 24, and the other end is connected by a pin 28 to a rod 27 of a hydraulic cylinder 26 which is pivotally supported on the front bracket 3 by a pin 25.

[0016] As shown in FIG. 2, the hydraulic cylinder 26 is connected to the hydraulic pump 3 via an electromagnetic switching valve 29.
0, and a relief valve 31 is connected to the hydraulic pump 30 in parallel with the electromagnetic switching valve 29. In addition, the solenoid 29a of the electromagnetic switching valve 29 and the power supply 32
The electric circuit connecting the pressure switch 2 to
1a is provided.

[0017] With the above configuration, when a load greater than the set value of the load pressure gauge 21, for example, the load of the screw 10 and the auger 11 is applied during auger work, the pressure switch 21a is turned on and the electromagnetic switching valve is switched on via the solenoid 29a. 29, the hydraulic cylinder 26 is contracted and the back tension wire rope 23 is pulled at the set pressure of the relief valve 31, and a bending stress corresponding to this constant set pressure is applied to the leader 4.

[0018] Therefore, the troublesome and erroneous operation of correcting the back tension wire rope by manual operation in the past is eliminated.

[0019] Furthermore, to explain the second invention with reference to FIGS. 1 and 3, the auger wire rope 7 and the back tension wire rope 23 are provided in the same manner as in the above invention, and as shown in FIG.
The end 7a of the auger wire rope 7, which is hung several times around the sheave 12 of the auger 11 and the sheave 9 of the top sheave block 8, is connected to the top sheave block 8 via a load voltmeter 41, and connected to the hydraulic cylinder 26. An electromagnetic proportional relief valve 42 is provided in the hydraulic circuit of the hydraulic pump 30.
A converter 43 is provided in the electric circuit of the solenoid 42a of the electromagnetic proportional relief valve 42 to convert the output voltage of the load voltmeter 41 into a current value and output the current to the solenoid 42a of the electromagnetic proportional relief valve 42. There is.

[0020] With the above configuration, when a load is applied to the front side of the leader during auger work, current flows from the load voltmeter 41 to the solenoid 42a of the electromagnetic proportional relief valve 42 via the converter 43, and the electromagnetic proportional relief valve 42 The hydraulic cylinder 26 is actuated to tension the back tension rope 23 with the relief pressure of the electromagnetic proportional relief valve 42 and apply a bending stress to the leader 4 corresponding to this pressure.

[0021] The back tension wire rope 23 is stretched by applying a pressure commensurate with the load on the auger side to the hydraulic cylinder 26.

[0022] Therefore, the leader 4 is subjected to backward bending stress due to pressure according to the load, and even if a load is applied to the front side of the leader during auger operation, the tension of the back tension wire rope 23 As a result, operability and safety are improved, and auger work can be performed smoothly.

【0023】

Effects of the Invention As described above, in the first invention, one end of the wire rope for back tension is attached to the back side of the auger of the top sheave block fixed to the upper end of the leader of the three-point support type pile driver. The other end is connected to the front bracket supporting the leader via a hydraulic cylinder, and the end of the auger wire rope is pivotally connected to the top sheave block via a load pressure gauge, and the hydraulic cylinder is operated. A solenoid switching valve and a relief valve are provided in parallel in the circuit, and a contact point of the load pressure gauge is provided in the electric circuit of the electromagnetic switching valve, so that the electromagnetic switching valve is switched by the operation of the load pressure gauge for back tension. Since the wire rope is tensioned, if a load that exceeds the set value on the load pressure gauge (for example, the load of the auger and screw) is applied during auger operation, the pressure switch is turned on and the electromagnetic switching valve is switched on to control the leader tensioning device. The hydraulic cylinder is contracted and the wire rope for back tension is constantly pulled at the set pressure of the relief valve, and a bending stress corresponding to this constant set pressure is applied to the leader, so the leader is forced to bend backwards with a constant pressure. Even when stress is applied and a load is applied to the front side during auger operation, the constant tension of the back tension wire rope eliminates the trouble and incorrect operation of manually correcting the back tension wire rope. Improved operability and safety, allowing smooth auger work.

Furthermore, in the second invention, a back tension wire rope is provided as in the above invention, and the end of the auger wire rope is pivotally connected to the top sheave block via a load voltmeter, so that the hydraulic cylinder can be operated. An electromagnetic proportional relief valve is provided in the circuit, and a converter for converting the output voltage of the load voltmeter into a current value is provided in the electrical circuit of the electromagnetic proportional relief valve, so that the output of the load voltmeter operates the electromagnetic proportional relief valve. Since the back tension rope is tensioned under control, when a load is applied to the front side of the leader during auger operation, current flows from the load voltmeter to the solenoid of the electromagnetic proportional relief valve via the converter, and the electromagnetic proportional relief valve is activated. A hydraulic cylinder is actuated by the valve, and the back tension wire rope is pulled by the relief pressure of the electromagnetic proportional relief valve, applying bending force to the leader, so a backward bending stress commensurate with the load is applied to the leader. Even if a load is applied to the front side during auger operation, the constant tension of the back tension wire rope eliminates the need for conventional manual operation and eliminates erroneous operations, improving operability and safety. Work can be done smoothly.

【0025】

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a leader tensioning device of the present invention;

FIG. 2 is a hydraulic/electrical circuit diagram showing an embodiment of the first invention;

FIG. 3 is a hydraulic/electrical circuit diagram showing an embodiment of the second invention;

[Fig. 4] Front view of a conventional three-point support type pile driver,

[Fig. 5] A and B are for explaining the working position of the double-sided rotary leader, A is an explanatory diagram when using an auger, B is an explanatory diagram when using a hammer,

FIGS. 6A and 6B are diagrams for explaining the working position of the end face fixed type leader; A is an explanatory diagram when an auger is provided, and B is an explanatory diagram when a hammer or drop auger is provided.

[Explanation of symbols]

1... Three-point support pile driver, 2... Main body, 3... Front bracket, 4... Leader, 5... Back stay, 6... Pulley, 7... Wire rope for auger, 7a... Rope 7 End, 8... Top sheave block, 9... Sheave, 10... Screw, 11... Auger, 12... Sheave of auger 11, 13... Hammer, 21... Load pressure gauge, 21
a...Pressure switch, 22...Bracket, 23
...Wire rope for back tension, 24,2
5... Pin, 26... Hydraulic cylinder, 27... Rod, 28... Pin, 29... Solenoid switching valve, 29
a... Solenoid, 30... Hydraulic pump, 31...
... relief valve, 32 ... power supply, 41 ... load voltmeter, 42 ... electromagnetic proportional relief valve, 42a ... solenoid, 43 ... converter.

Claims (2)

[Claims] 1. One end of a back tension wire rope is connected to the rear side of the auger of a top sheave block fixed to the upper end of the leader of a three-point support type pile driver, and the other end is connected to the leader through a hydraulic cylinder. The end of the wire rope for the auger is pivotally connected to the top sheave block via a load pressure gauge, and an electromagnetic switching valve and a relief valve are provided in parallel in the operating circuit of the hydraulic cylinder. , characterized in that a contact point of the load pressure gauge is provided in the electric circuit of the electromagnetic switching valve, so that the operation of the load pressure gauge switches the electromagnetic switching valve to tension the back tension wire rope. Back tension device for three-point support type pile driver. 2. One end of a back tension wire rope is connected to the rear side of the auger of a top sheave block fixed to the upper end of the leader of a three-point support type pile driver, and the other end is connected to the leader through a hydraulic cylinder. The end of the wire rope for the auger is pivotally connected to the top sheave block via a load voltmeter, and an electromagnetic proportional relief valve is provided in the operating circuit of the hydraulic cylinder, and the load voltmeter A converter for converting the output voltage into a current value is provided in the electric circuit of the electromagnetic proportional relief valve, and the output of the load voltmeter controls the electromagnetic proportional relief valve to tension the back tension wire rope. A back tension device for a three-point support type pile driver, characterized by the following: