JPH108869A - Down-the-hole hammer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the risk of members getting loose even in case of being rotated normally and reversely and connect and detach the members easily without using a special jig at the time of replacing parts in a down-the-hole hammer of such constitution that a top sub connected to a joint adaptor is connected to the upper end of a piston case with a built-in piston and that a drive sub enclosing a hammer bit movably forward/backward is connected to the lower end of the piston case. SOLUTION: A joint adaptor 18 and a top sub 17 are formed as an integral member. A piston case 1 and the top sub 17, and the piston case 1 and a drive subs 5 are respectively connected by forming connection parts on the side of the top sub 17 and drive sub 5 into polygonal shafts 19 or spline shafts while forming connection parts on the piston 1 side into recessed parts 20 into which the polygonal shafts 19 or spline shafts are fitted, and fitting both connection parts to each other. Pinholes 21 are formed at fit-in boundary parts, across both connection parts, and a pin 22 to be a key is inserted in a retractable state into each pinhole 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a down-the-hole hammer for excavating a hole for a pile as a foundation work in the fields of construction and civil engineering.

[0002]

2. Description of the Related Art As is well known, a down-the-hole hammer moves a hammer up and down by the movement of a piston and excavates by hitting. This structure is shown in FIGS. Is a hammer bit, and a drive sub 5 that accommodates the upper part of the hammer bit 3 so as to be able to move forward and backward is screwed into the lower end of the piston case 1.

The center portion of the hammer bit 3 is formed as a spline shaft, which fits into the inside of a drive sub 5 having a concave and convex engaging groove on the inner peripheral wall. In the figure, 6 is a foot valve, 7 is an O-ring, 8 is a bit retainer ring, and 9 is a piston retainer ring.

A rigid valve 11, a make-up ring 12, a valve guide 13, a valve spring 15, and a check valve 16 are disposed above the piston 2 with an O-ring 10 interposed therebetween and holding a choke 14 at the center. A top sub 17 serving as a valve seat of the check valve 16 is screwed into the upper part of the piston case 1.

[0005] The top sub 17 has a frusto-conical screw hole in the center, and a joint adapter 18 for connection to an auger shaft.
The frusto-conical screw formed at the lower part of was screwed here.

[0006] Thus, the joint adapter 18 and the top sub
17, the top sub 17 and the piston case 1, and the piston case 1 and the drive sub 5 are joined by screws.

[0007]

SUMMARY OF THE INVENTION The joint adapter 18
The down-the-hole hammer is connected to the tip of an auger shaft such as a screw shaft as an excavator, and excavates the ground while rotating with the auger shaft.

[0008] This rotation mainly excavates clockwise, but in a soft layer of the stratum, earth pressure is applied to the peripheral surface of the excavator, so that the outer periphery of the down-the-hole hammer may be held down. In such a situation, the left and right rotations are repeated not only to the right but also to the left to reduce friction on the outer periphery.

When the left rotation is adopted, there is a possibility that a portion joined by the screw is loosened and separated from each other.

In addition, if drilling by clockwise rotation continues for a long period of time, the screw will be hardened, and if the hammer bit 3 is replaced on site, it cannot be replaced without a special jig. Become. For this reason, a special removal and mounting jig (hydraulic chuck device, etc.) is required, and cannot be replaced at the site.

An object of the present invention is to solve the above-mentioned disadvantages of the prior art, so that there is no danger of loosening of the members even when the components are rotated forward and backward, and the components can be easily exchanged without using a special jig when replacing components. It is an object of the present invention to provide a down-the-hole hammer capable of binding and detaching a hammer.

[0012]

According to the present invention, in order to achieve the above object, first, a top sub which is connected to a joint adapter is connected to an upper end of a piston case having a built-in piston, and a hammer bit is freely movable at a lower end. In the down-the-hole hammer that connects the drive sub to be housed in the housing, the top sub that is connected to the joint adapter is formed as an integral body, and the connection between the piston case and the top sub and the connection between the piston case and the drive sub are performed using the top sub and the drive. The connection part on the sub side is a polygonal shaft or a spline shaft, and the connection part on the piston case is fitted as a recess into which these polygonal shafts or the spline shafts fit, and at the boundary part of this fitting. A pin hole is formed so as to straddle both, and a key pin can be inserted and removed freely into this pin hole. It is an effect.

Second, the pin hole is formed in the horizontal direction. Third, a stop ring is arranged before and after the inserted pin to prevent the pin from falling off, or the pin hole is inserted to prevent the pin from falling off. Fourth, the pin holes are pressed against the side of the pin, and fourthly, two sets of pin holes are formed in parallel with the upper and lower stages, and a total of four pin holes are formed. The point is to do so.

According to the first aspect of the present invention, since the top sub to be connected to the joint adapter is formed as a single body, there is no danger of loosening due to the screw connection as in the prior art. The connection between the piston case and the top sub and the connection between the piston case and the drive sub are such that the polygonal shaft or the spline shaft fits into a concave portion corresponding to the polygonal shaft or the spline shaft, and straddles both at the boundary of the fitting. Is locked by the pin hole provided in the first connector and the pin serving as a key, so that there is no danger that the screw connection as in the related art will loosen.

Further, in the case of parts replacement, if the pin is pulled out from the pin hole, the polygonal shaft or spline shaft fitted in the concave portion can be pulled out as it is, and simply and quickly without using a special jig on site. Exchange can take place.

According to the second aspect of the present invention, in addition to the above operation, the pin hole is formed in the horizontal direction, and the key pin is also inserted in the horizontal direction. The members are securely and firmly locked to each other in the horizontal direction.

According to the third aspect of the present invention, it is possible to easily prevent the pin from falling off by using the stop ring. According to the fourth aspect of the present invention, the stop bolt is provided on the side of the inserted pin. The pin can be easily prevented from falling off by pressing the tip.

According to the fifth aspect of the present invention, the locking is performed by a total of four pins arranged in the upper and lower stages, so that more secure and strong locking can be achieved.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a partially cutaway front view showing a down-the-hole hammer according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 3 is a cross-sectional view taken along the line BB of the same. The same components as those of FIGS. .

In the down-the-hole hammer of the present invention, a top sub 17 connected to a joint adapter 18 is connected to the upper end of a piston case 1 having a built-in piston, and the hammer bit 3 is stored at the lower end of the piston case 1 so as to be able to advance and retreat. Drive sub 5 to be connected.

First, in the present invention, the joint adapter 18 for connecting to the auger shaft and the top sub 17 are formed as a single body.

The connecting portion (joint) of the top sub 17 is formed as a polygonal shaft 19 (a hexagonal shaft in the illustrated example), and the connecting portion of the piston case 1 is fitted with the polygonal shaft 19. Thus, it is configured as a polygonal concave portion 20 corresponding to this. In the figure, reference numeral 35 denotes an O-ring as a seal disposed below the polygonal shaft 19 of the top sub 17.

Further, a groove having a semicircular cross section is formed in each of the boundary portions of the fitting between the polygonal shaft 19 and the concave portion 20 in the horizontal direction, and these two grooves are combined to form the top sub 17 and the piston case 1. A circular pin hole 21 that straddles both is formed in the horizontal direction.

The pin hole 21 is open to the outside, and a pin 22 serving as a key is inserted into the pin hole 21 through the opening so as to be freely inserted and removed.

A groove is formed in the front and rear positions of the inserted pin 22 in the circumferential direction of the hole, and a stop ring 23 for fitting the outer peripheral edge into the groove is arranged to prevent the pin 22 from coming off. 8 and 9 show the pin 22 and the stop ring 23. The pin 22 does not have a head at both ends, and the stop ring 23 has a donut shape that can be contracted in a partially cut-out shape. It is a ring.

The connection portion (joint) at the upper part of the drive sub 5 is also formed as a polygonal shaft 19 (in the illustrated example, a hexagonal shaft) so that the polygonal shaft 19 fits into the connection portion of the piston case 1. A polygonal concave portion 20 corresponding to this is formed, and furthermore, the same circular pin hole 21 as described above is formed in a horizontal direction at a boundary portion between the fitting thereof, and a pin 22 serving as a key can be freely inserted and removed in the pin hole 21. Shall be inserted. In addition, stop rings 23 for preventing slipping out are arranged at positions before and after the pins 22 to be inserted. In the drawing, reference numeral 33 denotes a packing, and reference numeral 34 denotes a bit receiving ring which collects two half-split type members to form a ring.

The connection between the drive sub 5 and the hammer bit 3 is the same as in the prior art. The center of the hammer bit 3 is formed as a spline shaft, which is formed on the inner peripheral wall of the drive sub 5 having an uneven groove for engagement. It fits into the recess 24.

In this manner, the top sub 17 and the piston case 1 and the piston case 1 and the drive sub 5 are connected by fitting the polygonal shaft 19 and the polygonal concave portion 20 corresponding to the polygonal shaft 19, so that the top sub 17 and the drive sub 5 can be rotated with respect to either left or right rotation. However, the integrity is maintained, and detachment is prevented by the pin 22 serving as a key.

In order to separate them by exchanging members or the like, the pin 22 can be pulled out by removing the stop ring 23. If the polygon shaft 17 of the drive sub 5 or 17 is pulled out, it can be easily separated.

The connecting portion (joint) of the top sub 17 and the drive sub 5 is formed as a spline shaft 25 as shown in FIGS. 4 and 5 instead of a polygonal shaft. A spline groove may be formed so that this fits.

Further, as a second embodiment of the present invention, a pin
To prevent the 22 from dropping off, use a pin as shown in FIGS.
Numeral 22 has a head portion 22a, and a recess 22b having a flat contact surface is formed on the middle side. Then, a locking bolt 27 is inserted from the outside, and its tip is pressed against the recess 22b.

FIGS. 12 and 13 show a third embodiment of the present invention.
A pin 22 of the type commonly used in earth augers or the like having a spring steel 32 interposed in the head 22a as shown in FIG.

In the above-described embodiment, the pin holes 21 are formed as a pair of left and right parallel members. However, as a fourth embodiment of the present invention, as shown in FIG.
A total of four pairs may be formed in the upper and lower rows so that the upper and lower rows are orthogonal to each other, and locking may be performed by a total of four pins 22 inserted therein.

By locking with a large number of pins 22 in this manner, more secure and strong locking can be achieved.

FIG. 6 shows a case in which the down-the-hole hammer of the present invention is covered with a hammer cover 28. The hammer cover 28 is exchanged according to the excavation diameter. Screw shaft 31 is located. Vertical protrusions 30 are formed at appropriate intervals on the hammer cover 28 so as to secure vertical grooves, so that a gap for passing air around the outer periphery of the rotating hammer cover 28 can be secured. .

As the excavator, there is an earth auger type in which the driving device moves up and down along the leader mast, and a type in which the rod itself slides while the outer periphery of the rod is chucked by the driving device. Therefore, it is also possible to use a method in which an auger shaft is used as a polygonal rod instead of the upper casing 29 or the screw shaft 31 to be connected to the upper part of the down-the-hole hammer and used as a clutch for rotationally driving the rod.

[0037]

As described above, the down-the-hole hammer of the present invention does not have the possibility of loosening the members even if the hammer is rotated in the normal or reverse direction, and can easily replace parts without using a special jig when replacing parts. Can be bonded and separated.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a down-the-hole hammer according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a cross-sectional plan view showing another example of the connection between the top sub and the piston case.

FIG. 5 is a cross-sectional plan view showing another example of the connection between the drive sub and the piston case.

FIG. 6 is a vertical sectional side view when a hammer cover is provided.

FIG. 7 is a sectional view taken along the line CC of FIG. 6;

FIG. 8 is a plan view of a pin used in the first embodiment.

FIG. 9 is a plan view of a stop ring used in the first embodiment.

FIG. 10 is a plan view of a pin used in the second embodiment.

FIG. 11 is a cross-sectional plan view of a main part showing the second embodiment.

FIG. 12 is a plan view of a pin used in the third embodiment.

FIG. 13 is a cross-sectional plan view of a main part showing a third embodiment.

FIG. 14 is a longitudinal sectional side view of a main part showing a fourth embodiment.

FIG. 15 is a vertical side view of a conventional down-the-hole hammer.

FIG. 16 is an exploded perspective view of a conventional down-the-hole hammer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Piston case 2 ... Piston 3 ... Hammer bit 5 ... Drive sub 6 ... Foot valve 7 ... O-ring 8 ... Bit retainer ring 9 ... Piston retainer ring 10 ... O-ring 11 ... Rigid valve 12 ... Makeup ring 13 ... Valve guide 14 ... Choke 15 ... Valve spring 16 ... Check valve 17 ... Top sub 18 ... Joint adapter 19 ... Polygon shaft 20 ... Recess 21 ... Pin hole 22 ... Pin 22a ... Head 22b ... Recess 23 ... Stop ring 24 ... Recess 25 ... Spline shaft 26 ... Recess 27 ... Retaining bolt 28 ... Hammer cover 29 ... Upper casing 30 ... Protrusion 31 ... Screw shaft 32 ... Spring steel 33 ... Packing 34 ... Bit receiving ring 35 ... O-ring

Claims (5)

[Claims] In a down-the-hole hammer, a top sub that connects to a joint adapter is connected to an upper end of a piston case containing a piston, and a drive sub that stores a hammer bit so as to be able to move forward and backward is connected to a lower end of the piston case. Formed as an integral body, the connection between the piston case and the top sub and the connection between the piston case and the drive sub are made by connecting the connection part of the top sub or the drive sub to a polygonal shaft or a spline shaft, and connecting to the piston case. The parts are fitted as recesses into which these polygonal shafts or spline shafts fit, and a pin hole is formed so as to straddle both at the boundary of the fitting, and a pin serving as a key is formed in this pin hole. A down-the-hole hammer that can be inserted and removed freely. 2. The down-the-hole hammer according to claim 1, wherein the pin hole is formed in a horizontal direction. 3. The down-the-hole hammer according to claim 1, wherein a stop ring is disposed before and after the inserted pin to prevent the pin from falling off. 4. The down-the-hole hammer according to claim 1, wherein a tip of a stop bolt is pressed against a side of the inserted pin to prevent the pin from falling off. 5. The pinhole according to claim 1, wherein two sets of pinholes are formed in parallel in the upper and lower stages, and a total of four pinholes are formed, and the pinholes are locked by four pins inserted therein. Down the hole hammer.