JP2014065121A - Noise-reducing underground boring hammer drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise-reducing underground boring hammer drill which can significantly reduce noise during boring and can have powerful boring performance.SOLUTION: For striking a hammer bit 50 while pneumatic pressure moves a piston 40 up and down, an air compression chamber is provided between the piston and the hammer bit to strike the hammer bit through pressure of air compressed in the compression chamber.

Description

  The present invention relates to a hammer drill for underground drilling for installing a pile for ground reinforcement, and more specifically, when a piston hits and drills a hammer bit while reciprocating up and down by pneumatic pressure. By hitting the hammer bit with the pressure of the air compressed in the air compression chamber provided between the piston and the hammer bit, noise during drilling can be significantly reduced, and powerful drilling performance can be achieved. The present invention relates to a hammer drill for underground drilling that can have noise.

  In construction work, steel pipe piles or concrete piles are generally placed on the ground to reinforce the ground.

  Conventionally, piles for ground reinforcement are placed on the ground (including soft ground). Conventionally, after piles are erected vertically, the piles are laid underground by hitting the upper part of the pile to be erected with a pile driver. Had been laid directly on. However, in this pile construction method using pile driving, the impact noise is very large, so there are frequent complaints of noise pollution in the city center and residential areas, which makes it difficult to apply this method. It has become.

  Therefore, in recent years, it has been replaced by a method of reinforcing the ground by inserting a pile into the drilled hole after being drilled in the basement, or placing a steel frame and concrete mortar.

  By the way, drills used to drill underground to insert piles can be divided into screw drills and hammer drills, and screw drills have the advantage that they hardly generate noise, but they are difficult to drill rocks. There is.

  On the other hand, the hammer drill has a special diamond tool that can generate a powerful force and can also crush the rock, and the rock layer can be easily drilled, while the noise during drilling is very large. is there.

  As an example of a hammer drill, registered utility model No. 20-0348757 (200.4.14) hammer bit piston reverse operation prevention device, registered utility model No. 20-043274 pneumatic directional hammer and hammer bit, Also, reference can be made to a pneumatic hammer drill or the like disclosed in published utility model publication No. 20-2008-0004299 (2008.10.2).

  The conventional pneumatic hammer drill described above hits a hammer bit attached to the lower end of the hammer drill and fixed with a diamond tool with a piston that is lifted and lowered by air pressure, and at the same time, the hammer drill is driven by a rotational force provided from an auger driver. Drilling work is performed while rotating.

  However, as described above, since the hammer drill has excessively high working noise despite its strong drilling performance, in order to compensate for this problem, the hammer bit is divided into several parts to reduce the noise during drilling. Has been tried. By dividing the hammer bit in this way, the noise during drilling could be reduced, but this time the drilling performance was significantly reduced, causing another problem such as a delay in drilling work time. It has not been used in the field.

  In view of the above-described problems, the present invention provides a hammer drill for drilling underground, in which a piston is reciprocated up and down by air pressure while striking and drilling a hammer bit. A hammer drill for noise reduction type underground drilling that can significantly reduce the noise during drilling by striking the hammer bit with the pressure of air compressed in the compression chamber and has strong drilling performance. The purpose is to provide.

  The noise-reducing underground drilling hammer drill according to the present invention is an underground drilling hammer drill having a piston that strikes a hammer bit while reciprocating up and down by pneumatic pressure, and a region where the hammer bit and the piston are in contact ( The part) is equipped with a compression chamber, and when the hammer hits the hammer bit, the hammer bit is struck by the air pressure compressed in the compression chamber, and the noise that can greatly reduce the operation noise of the hammer drill It is a hammer drill for reducing underground drilling.

  In the hammer drill of this invention, the space which forms a compression chamber is provided in the upper side of a hammer bit, and the lower end surface of a piston.

  In the compression chamber, an outer cylinder having a diameter capable of moving the piston up and down is provided around the upper end of the hammer bit, and the hollow (inner diameter wall surface) of the hammer bit has an inner side so that compressed air does not leak through the hollow. A cylinder is provided.

  As another modification of the compression chamber, a space portion consisting of a fixed space is provided at each of the lower end portion of the piston and the upper end portion of the hammer bit, and the two space portions are combined when the piston and the hammer bit are brought close to each other. Thus, the compression chamber may be configured to form a predetermined space.

  In the present invention, when the lower end portion of the piston and the upper end portion of the hammer bit are brought close to each other, the operating pressure of the piston is transmitted to the piston by the air pressure compressed in the compression chamber, so that the piston is applied to the upper end of the hammer bit. Since the impact energy is not directly transmitted to the piston but is struck via compressed air pressure, noise generated during drilling can be significantly reduced.

  In addition, the hammer bit constituting the hammer drill according to the present invention drills the rock through pneumatic striking, so that not only can noise during drilling be significantly reduced, but drilling performance can be ensured, It is extremely effective for drilling work in the city center and residential areas.

It is the longitudinal cross-sectional view of the hammer drill which showed the state before the action | operation of the hammer drill which concerns on this invention. It is the longitudinal cross-sectional view of the hammer drill which showed the state in which air flows in into the hammer drill which concerns on this invention. It is a longitudinal cross-sectional view of the hammer drill which showed the piston downward movement of the hammer drill which concerns on this invention. It is a longitudinal cross-sectional view of the hammer drill which showed the piston downward movement of the hammer drill which concerns on this invention. It is the longitudinal cross-sectional view of the hammer drill which showed the state which the piston of the hammer drill which concerns on this invention approached into a compression chamber. It is the longitudinal cross-sectional view of the hammer drill which showed the state which the piston of the hammer drill which concerns on this invention compressed the compression chamber.

  Hereinafter, a hammer drill for underground drilling according to the present invention will be described in detail with reference to the drawings.

  FIGS. 1-6 is principal part sectional drawing which showed the hammer drill for underground drilling, and shows the operating state of the hammer drill at the time of a driving | operation with the longitudinal cross-sectional view in order.

  First, the hammer drill (100) is connected to an auger driver (not shown) through the top sub (10), and is supported in a state of being vertically set on the ground.

  The hammer drill (100) is supplied with pressure air through an air inflow hole (11) provided in the top sub (10), and is rotated by the rotational force provided from the auger driver.

  As shown in the enlarged view A of FIG. 2, the high-pressure air flowing into the air inflow hole (11) distributes the air provided in the air valve (20) while forcibly opening the check valve (21) with pressure. It enters between the outer sleeve (30) and the outer sleeve (31) through the hole (22) and the guide passage (23) and instantaneously reduces the internal pressure of the working chamber (24). To rise.

  When the pressure in the working chamber (24) between the outer sleeve (30) and the inner sleeve (31) instantaneously increases, as shown in FIG. 3, the check valve (21) is brought into the air inlet hole (11) by the pressure increase. The piston (40) is separated from the upper surface of the hammer bit (50) while the piston (40) moves to the upper side of the outer sleeve (30). And air is exhausted through the air exhaust hole (51) of the hammer bit (50) exposed by the rise of the piston (40).

  When the piston (40) rises, as shown in the enlarged view C of FIG. 3, the sealing protrusion (42) provided on the outer peripheral surface of the piston (40) becomes the inner peripheral surface (inner diameter wall surface) of the outer sleeve (30). In the working chamber (24), the piston (40) is instantaneously lowered by the air flowing in from the air inflow hole (11).

  As described above, the upper end portion of the hammer bit (50) is hit by the up-and-down movement of the piston (40). The specific configuration will be described below.

  As shown in enlarged view E of FIG. 5, the air in the compression chamber (52) is compressed while the lower end of the piston (40) enters the compression chamber (52).

  The compression chamber (52) is formed in a region in the outer sleeve (30) where the hammer bit (50) and the piston (40) are in contact with each other. The compression chamber (52) has an inner diameter into which the piston (40) is inserted and a predetermined height. And an outer cylinder (54a) having an outer diameter and an inner cylinder having an outer diameter inserted into a hollow (inner diameter wall surface) of the piston (40) at the upper end of the air exhaust hole (51) of the hammer bit (50) (54b).

  The outer cylinder (54a) has an outer diameter that is substantially the same as the inner diameter of the outer sleeve (30), and is assembled by being inserted into the outer sleeve (30), as shown in the enlarged view D of FIG. As described above, an air leakage groove (53) is provided between the inner peripheral surface of the outer sleeve (30) and arranged at regular intervals in the circumferential direction.

  The air leakage groove (53) includes a hole (54c) communicating with the air passage (56) provided on the circumferential surface of the drive sub (57), and the piston (40) is connected to the compression chamber (52). ), The air existing around the upper portion of the hammer bit (50) is exhausted through the air exhaust hole (51) by the descending piston (40), and the piston (40) enters the compression chamber 52. The air around the piston cools the hammer bit (50) while being exhausted through the air leakage groove (53), the hole (54c) and the air passage (56).

  A small amount of air is exhausted into the grooves arranged in the axial direction at regular intervals on the circumferential surface of the drive sub (57) via the air passage (56).

  The inner cylinder (54b) prevents air compressed in the compression chamber (52) from leaking into the air exhaust hole (51) while the piston (40) enters the compression chamber (52). Provides a guiding action to align (40) in place on the hammer bit (50).

  Further, as shown in FIG. 6, a shock absorbing member (55) such as a highly elastic rubber material having an expansion / contraction force is disposed on the upper end of the hammer bit (50) as shown in FIG. It is preferable to relieve the collision pressure that collides with the hammer bit when the piston (40) reaches bottom dead center.

  When the piston (40) enters the compression chamber (52) and the piston reaches the bottom dead center and the compression force becomes maximum, the compression chamber (52 is arranged so that the bottom surface of the piston is in contact with the upper end of the buffer member. ) Is preferably designed. This not only prevents the shock-absorbing member (55) from being damaged by the impact of the piston (40), but also maximizes the punching performance of the hammer bit (50) by ensuring the greatest air compression force. This is because the noise during drilling can be further reduced.

  As explained above, the noise-reducing underground drilling hammer drill according to the present invention pierces the ground by striking the hammer bit with the air pressure generated by the compression of the piston, greatly increasing the noise during drilling. Can be reduced.

  DESCRIPTION OF SYMBOLS 10 ... Top sub, 11 ... Air inflow hole, 21 ... Check valve, 20 ... Air valve, 22 ... Air distribution hole, 23 ... Guide passage, 24 ... Working chamber, 30 ... Outer sleeve, 31 ... Inner sleeve, 40 ... Piston 42 ... sealing projection, 50 ... hammer bit, 51 ... air exhaust hole, 52 ... compression chamber, 53 ... groove for air leakage, 54a ... outer cylinder, 54b ... inner cylinder, 54c ... hole, 55 ... buffer member, 56 ... Air passage, 57 ... Drive sub, 100 ... Hammer drill

Claims (2)

It is a hammer drill for underground drilling with a piston that strikes a hammer bit while reciprocating up and down by pneumatic pressure,
A compression chamber (52) is provided in a region in the outer sleeve (30) where the hammer bit (50) and the piston (40) are in contact with each other;
The compression chamber (52)
An outer cylinder (54a) having an inner diameter into which the piston (40) is inserted and a predetermined height;
An inner cylinder (54b) disposed at the upper end of the air exhaust hole (51) of the hammer bit (50) and having an outer diameter inserted into the hollow of the piston (40). A hammer drill for underground drilling that features noise.   The hammer drill for noise-reducing underground drilling according to claim 1, wherein a buffer member (55) is attached to the bottom surface of the compression chamber (52).

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