JPS5898523A - Device for preventing production of ground vibration due to striking - Google Patents

Abstract

PURPOSE:To perform a reliable sealing, by a method wherein a small-sized part of an anvil is fitted in a medium sealing chamber transferring a blow power to a pile head, and a seal is attached between a large-sized part of an anvil and a device body to provide a pressure reducing system. CONSTITUTION:If an anvil head 11 is hit by pressure through falling of a hammer ram 26 lifted by a ram elevating mechanism 25n, its blow power compresses a pressure accumulating medium Y, such as silicone oil, in a medium sealing chamber 6 through an anvil 8. A pile chucked by a pile head retainer member 4 is driven by the pressure force, and thereby an excessive blow power is prevented from being momentarily exerted on the pile head. The anvil consists of a small-sized fitting part 8a and a large-sized fitting part 8b, a liquid tight seal is attached between the large-sized fitting part 8b and a driven body 7a, and a pressure, being exerted on the seal, decreases due to a difference in a pressure receiving area between the small-sized fitting part 8a and the large-sized fitting part 8b, which results in performing a reliable sealing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for preventing vibrations in the ground caused by the impact of a pile driving mud, an f-hammer, etc. used in the construction of foundation piles, for example.

The present applicant has developed a device capable of preventing the occurrence of ground vibrations caused by impact, and has already filed patent application No. 149794/1983. This device includes a main body having a medium chamber filled with a liquid or liquid pressure accumulation medium, and an anvil that is movable up and down, a part of which is fitted into the medium chamber. After storing energy in the pressure storage medium, this stored energy is continued for a predetermined period of time immediately after the end of the impact, and gradually released over a long period of time in addition to the time required to store the energy, increasing the restoring force of the ground. This is so that an impulse action is exerted in the opposite direction.

However, this device has a large number of parts, is complex in structure and assembly, and is expensive. In addition, there is a risk of component failure due to the impact during impact, and furthermore, during impact, a portion of the pressure-accumulating medium escapes from the liquid-tight seal. In the event of a leak, the duration of the impulse action changes, so the liquid-tight rail must have extremely high performance.

The present invention has been proposed under the above circumstances, and its purpose is to not only prevent the occurrence of ground vibration caused by impact, but also to solve the above-mentioned conventional problems, and to improve the durability of impact. An object of the present invention is to provide a device for preventing the occurrence of ground vibrations caused by ground vibrations.

That is, the present invention provides a device main body having a medium enclosure chamber filled with a liquid or liquid pressure accumulation medium, and an anvil insertion hole that has at least seven intermediate steps and is connected to the medium enclosure chamber, The anvil, which is partially fitted into the medium enclosure chamber, is inserted into the small diameter part of the anvil insertion hole and has a lower end facing the medium enclosure chamber, and at least one large diameter part which is fitted into the large diameter part of the anvil insertion hole. an inset portion, and a pressure storage medium reservoir is formed between the anvil and the stepped portion;
In addition, the anvil or the device body is provided with a passage that communicates the above chambers with a check valve that only allows flow from the pressure accumulation medium storage chamber toward the medium sealing chamber, and the maximum diameter fitting part on the upper side of the anvil and the device body are provided. This device is characterized in that a liquid-tight seal is provided between the device and the device body, and a pressure reduction measure is applied between the insertion portion below this and the device main body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a pile-driving mud lug/meter embodying the present invention will be described with reference to the drawings.

In the figure, reference numeral 1 denotes a cylindrical cylinder, and a sliding arm 2 is protruded from the outer circumferential surface of the cylinder and is slidably guided by a leader X that stands on the ground. A forest ground vibration generation prevention device 3 is provided at the lower end of the cylinder 1. A pile head support member 4 for supporting the pile head is detachably attached to the lower end of the device 3 by means of a connector 5. A chuck or a cap is used for the pile cap support member 4, and this embodiment shows a hydraulically operated chuck for steel piles.

The ground vibration generation prevention device 3 uses a liquid or liquid pressure accumulation medium Y.
It is formed as shown in detail in FIG. 2, comprising a device main body 7 having a medium enclosure chamber 6 filled with the medium, and an anvil 8 which is partially fitted into the medium enclosure chamber 6 and is movable up and down. . That is, the apparatus main body 1 has upper and lower members 7a and 7b connected by a connector 9, and an anvil insertion hole is provided in the upper member 7a. This insertion hole is formed from a small diameter part 10m whose lower end is connected to the medium enclosure chamber 6, a large diameter part 10b provided above this, and a stepped part 10c forming a boundary between these parts 10* and 10b. On the other hand, the anvil 8 includes a small diameter fitting part 8a which is fitted into the small diameter part 10a and whose lower end faces the medium enclosure chamber 6, and a large diameter fitting part 8b which is fitted into the large diameter part 10b above this. A door 11 is connected to the annobil at the upper end of the stepped cylinder. In the figure, 771 is a connecting shaft, and 11b is a retaining pin. A pressure accumulating medium reservoir Z2 is formed between the stepped portion of the anvil 8 and the stepped portion 10e. moreover,
The anvil 8 is provided with a passage 13 that connects the pressure accumulation medium storage chamber 12 and the medium enclosure chamber 6, and this passage 13 is provided with a reverse check in the intermediate portion that allows flow only from the pressure accumulation medium accumulation chamber 12 in the direction of the medium enclosure chamber 6. It has a valve 14. This reverse valve 14 is opened by a force that is less than the pressure resistance of a liquid-tight seal 15, which will be described later. In addition, the large diameter portion 10b and the large diameter fitting portion 8
An annular liquid-tight seal 15 for liquid-tightness is provided between the two and b.

This seal 15F'i is pressed by an annular seal holder 16VC, and a dustproof seal 17 is further provided between this holder 16 and the large diameter fitting portion 8b as required. Furthermore, an annular liquid-tight seal 18, for example, is provided between the small diameter portion 10m and the small diameter entry portion 81 as a pressure reducing measure. This seal 18 is pressed against an annular seal retainer 19. In the figure, 20 is a metal, 21 is an air vent plug, 22 is a medium enclosure plug, 23 is a drain plug, and 24 is a vibration isolating rubber. Further, as the pressure accumulating medium Y sealed at the required pressure in the device 3 having the above configuration, petroleum-based hydraulic oil such as turbine oil, silicone oil, glycerin, etc. are used, and in this embodiment, the case of turbine oil is used. It shows. In addition,
In this embodiment, the diameter d of the pressure receiving surface of the small diameter fitting portion 8a
is 240eW1, and the diameter of the large diameter fitting part 8b is 480
Set to cIR.

On the other hand, a hammer ram 26 is housed within the cylinder 1 and is moved up and down by a ram elevating mechanism 25 and presses the anvil 8 when it falls. At the lower end of the hammer ram 26, a non-metallic material for noise reduction, such as hardwood 27, and a coil spring 28 for tightening the hardwood 27 are attached. Note that the hardwood 27 may be attached to the upper surface of the anvil 8.

In this embodiment, the ram elevating mechanism 25 is attached to the cylinder 1 and includes a pair of fixed pulleys 29, 29b and a movable pulley 29c, and a pulley having a wire lobe 3Q guided by these and connected to the hammer ram 26 at one end. The ram elevating mechanism 25 includes a device 29 and a cylinder 31 that moves the movable pulley 29e'' up and down.The ram elevating mechanism 25 may be a winch provided on the ground side.

Further, 32 indicates a lower end support structure of the cylinder 1.

According to the above-mentioned drop hammer, piling is performed by dropping the hammer ram 26 raised by the ram lifting mechanism 25 and pressing the dowel 11 against the anvil 8 with the ram 26. In this case, the impact force by the hammer ram 26 compresses the pressure accumulation medium Y in the medium enclosure chamber 6 to generate a high medium pressure, and the pile is driven with this pressure. Excessive impact force is prevented from acting instantaneously, thereby preventing the pile cap from breaking standard (particularly noticeable in the case of p Ct#iψ).

Furthermore, as the pressure storage medium Y is compressed (elastic strain) by the device 3 of the present invention, a part of the impact energy is stored in the pressure storage medium Y, so that the penetration speed of the pile can be reduced, and the rebound speed of the pile after the impact is completed can be reduced. Can be reduced. The decrease in the rebound speed of the pile is due to the fact that the energy stored in the pressure storage medium Y is continuously released for a predetermined period of time after the impact ends.
, is realized by the impulse action that is applied to the restoring force of the ground through the pile as a reaction force while pushing up the hammer ram 26.

Therefore, by reducing the penetration and rebound speeds of piles, it is possible to effectively prevent the occurrence of ground vibrations associated with pile driving.

According to the above-mentioned device 3, the liquid-tight seal 15 can be easily configured, the pressure accumulation medium Y does not leak, and the above-mentioned predetermined ground vibration prevention effect can be maintained for a long period of time. That is, the anvil 8 has the above dimensions (d =
240 on.

D = 480 am), the small diameter insertion part 8a
Input m 8 b (D pressure receiving surface 1t S 21d ”x4
It is 753π σ2 in 8°. The maximum instantaneous pressure generated in the medium enclosure chamber 6 by the striking force of the hammer ram 26 is 299,700 t.
If it is on, the small diameter fitting part 8@ is 299700/
452km 63k17/c! The large diameter fitting portion 8b receives a pressure of 299700/753 x 39 12 per unit area 1). This means that the liquid-tight seal 18 receives a pressure of 6 e 3 '/crrr and the liquid-tight seal 15 receives a pressure of 398 kg/bacteria, so the final liquid-tight seal 15 has a large pressure-resistant structure. Even if a material with low pressure resistance is used, a reliable seal can be achieved. It should be noted that when performing a liquid-tight seal without providing the large-diameter fitting portion 8b as in the present invention, it goes without saying that a high pressure of 663 kli+/n is applied as described above. Due to the return action, the liquid-tight seal 18 requires a special sealing function.
Therefore, the liquid-tight seal 18 with the above 663 kg/C
It is not necessary to use a material that can withstand the pressure of In. Further, due to the striking force of the hammer ram 26, a part of the pressure accumulating medium Y flows from the medium enclosure chamber 6 through the liquid-tight seal 18 portion into the pressure accumulating medium reservoir chamber 12, but this portion starts to be struck by the hammer ram 26. Immediately after, it is returned to the medium enclosure chamber 6. That is, the pressure accumulating medium in the pressurizing medium enclosure chamber 6 and the accumulating medium reservoir chamber 12 is pressurized at time n due to the striking force of the hammer ram 26, but since the above-mentioned area Sl t s is in the relationship Ss>Sl. ,
The compression speed of the pressure storage medium in the pressure storage medium storage chamber 12 is faster.

As a result, the pressure accumulation medium in the pressure accumulation medium storage chamber 12 flows into the passage 13.
The check valve 14 is pushed open through the medium, and the medium flows into the medium enclosure chamber 6. Of course, this returning action is performed at the very initial stage when the pressure storage medium Y in the medium enclosure chamber 6 is compressed, so that the internal pressure of the pressure storage medium storage chamber 12 at that time is equal to the liquid-tight seal 1.
Since the pressure resistance is lower than the pressure resistance of 5, the pressure accumulation medium will not leak from the liquid-tight seal 15. Moreover, according to the device 3, the small diameter fitting part 81 is provided in the anvil 8, and the lower end thereof is inserted into the medium enclosure chamber 6 to compress the pressure accumulation medium Y. Therefore, the small diameter fitting part 8a The pressure receiving area of is reduced.

Therefore, it is easy to push the small diameter fitting portion 8a into the pressure storage medium Y, and a predetermined elastic strain can be generated in the pressure storage medium Y even with a relatively small impact force.

Furthermore, since the medium enclosure chamber 6 of the present device 3 is single, there is no need for a large number of parts constituting a check, a valve, a throttle, a sedge ring, etc., as in the conventional device. Therefore, the structure is extremely simple, it is easy to assemble and can be manufactured at low cost, and there is almost no deformation or damage to the component parts despite the impact caused by impact.

Note that the present invention is not limited to the above-mentioned embodiment. A plurality of each may be provided. In this case, a plurality of pressure accumulating medium reservoirs are formed in the vertical direction, and these reservoirs are either directly connected to the medium filling chamber through passages with check valves, or the upper and lower reservoirs are connected to the lower reservoir. It shall be connected via a passageway with a check valve to allow circulation to the side. Further, as a pressure reduction measure, a choke seal may be used instead of a liquid-tight seal. In this case, multiple configurations are simple and costs can be further reduced. Furthermore, the passage with the check valve may be provided in the main body of the device. Further, the present invention is not limited to a pile driving drop hammer, but can be implemented by being incorporated into a press machine, a forging machine, or the like. In addition, in carrying out the present invention, unless it is contrary to the gist of the invention, the main body of the device may be used.

Media enclosure chamber, anvil insertion hole, small diameter hole, large diameter hole.

Specific structure, shape, 9 positions, and 1 dimension, including step part, anobile, large-diameter fitting part, small-diameter fitting part, 1 passage of pressure storage medium reservoir, check valve, liquid-tight seal, and pressure reduction measures.

It goes without saying that the material and the composition of the hydraulic medium are not limited to the one embodiment described above, and that various configurations can be implemented.

The gist of the present invention described above is the structure described in the claims. Therefore, according to the present invention, part of the impact energy can be stored in the pressure storage medium, and this energy can be gradually released after the impact is completed, thereby exerting an opposite impulse action on the restoring force of the ground. , it is possible to prevent the occurrence of ground vibration. Further, according to the present invention, an accumulating medium reservoir is provided above the medium enclosure chamber and between the device main body and the anobil, and the two chambers are connected by a passage with a check valve, so that the Since the pressure accumulation medium is returned from the pressure accumulation medium storage chamber to the medium enclosure chamber, a constant amount of pressure accumulation medium can be secured in the medium enclosure chamber without leakage of the pressure accumulation medium.

Therefore, the function of preventing ground vibration generation can be maintained for a long period of time, and a highly liquid-tight seal is not required between the compartments. The present invention provides the pressure storage medium storage chamber to increase the pressure receiving area, and also provides depressurization measures between the two chambers, and provides a liquid-tight seal between the large-diameter insertion part of the anvil and the main body of the device. Even if a liquid-tight seal with low pressure resistance is used, it can be reliably sealed for a long period of time. Furthermore, the present invention has practical effects such as being simpler in structure, easier to assemble, and cheaper to manufacture than conventional devices.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a partially cutaway side view, FIG. 2 is an enlarged vertical cross-sectional view of the main part, and FIG.
It is a cross-sectional view along the line ■-■ in the figure. Y... Pressure accumulation medium, 6... Medium enclosure chamber, 7... Device main body, 8... Anvil, 8a... Small diameter fitting part, 8b...
...Large diameter fitting part, 10a...Small diameter part, 10b...Large diameter part, 10c...Step part, 12...Pressure medium storage chamber, 1
3... Passage, 14... Check valve, 15... Liquid-tight seal, 18... Pressure reduction measure (liquid-tight seal).

Claims (1)

[Claims] The device main body has a medium enclosure chamber filled with a liquid or liquid pressure accumulation medium, and a vertically movable anvil whose part is fitted into the medium enclosure chamber, and the device absorbs the initial energy of the impact by the striking body that strikes the anvil into the pressure accumulation medium. After storing this stored energy, the stored energy is continued for a predetermined period of time immediately after the end of the impact, and is gradually released over a long period of time longer than the time required for the energy storage, counteracting the restoring force of the ground. In a device for preventing the occurrence of ground vibration caused by a blow so as to exert an impulse action, the device main body is provided with an anvil insertion hole having at least one stepped portion in the middle and connected to the medium enclosure chamber, and the anvil is inserted into the anvil. A small diameter fitting part that is fitted into the small diameter part of the annobil insertion hole and whose lower end faces the medium enclosure chamber, and at least one large diameter fitting part that is fitted into the large diameter part of the annobil insertion hole, and the annobil and the above-mentioned stage are formed. A pressure accumulating medium reservoir is formed between the chamber and the anvil or the device body has a check valve that allows flow only from the pressure accumulating medium reservoir toward the medium sealing chamber, and a passage communicating between the above chambers is provided. A striking device characterized in that a liquid-tight seal is provided between the maximum diameter insertion part on the upper side of the anvil and the device body, and depressurization measures are taken between the insertion part lower than this and the device body. Accompanying ground vibration prevention device.