US2786451A

US2786451A - Pneumatic rotary drill hammer

Info

Publication number: US2786451A
Application number: US567614A
Authority: US
Inventors: Richard O Dulaney
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-02-24
Filing date: 1956-02-24
Publication date: 1957-03-26
Anticipated expiration: 1974-03-26

Description

March 26, 1957 R. o. DULANEY PNEUMATIC ROTARY DRILL HAMMER 2 Sheets-Sheet 1 Filed Feb. 24, 1956 FIG. .1.

INVENTOR. P/CHAQD O. 004 A/VEY,

2 Sheets-Sheet 2 FIG. 6.

R. O. DULAN EY PNEUMATIC ROTARY DRILL HAMMER xmx P/ March 26, 1957' Filed Feb. 24, 1956 I N V EN TOR.

Fla/74490 Q 004 4N5 V,

flTTOA/EYS.

PNEUMATIC RUTARY DRILL HAMMER Richard 0. Dulaney, Fort Worth, Tex.

Application February 24, 1956, Serial No. 567,614

3 Claims. (Cl. 121-30) This invention relates to well drilling equipment, and more particularly to an air hammer for a well drilling apparatus.

The main object of the invention is to provide a novel and improved air hammer device operated by compressed air, or similar fluid under pressure, and being particularly arranged to cooperate with the bit of a rotary well drilling tool, the improved air hammer being simple in construction, being easy to install on a well drilling pipe, and being provided with means for receiving and supporting a well drilling bit therebeneath.

A further object of the invention is to provide an improved air hammer for a well drilling apparatus, said air hammer involving relatively inexpensive components, being rugged in construction, being reliable in operation, and being easy to maintain in working condition.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure 1 is a vertical cross-sectional view taken axially through the lower portion of a well drilling pipe provided with an air hammer constructed in accordance with the present invention;

Figure 2 is a horizontal cross-sectional view taken on the line 22 of Figure 1;

Figure 3 is a horizontal cross-sectional view taken on the line 3-3 of Figure 1;

Figure 4 is a horizontal cross-sectional view taken on the line 4-4 of Figure 1;

Figure 5 is a vertical cross-sectional view, similar to Figure 1, but showing the piston element of the air hammer in a partly elevated position prior to reaching the top end of its stroke; and

Figure 6 is a vertical crosssectional view of the air hammer, similar to Figure 1, but showing the piston element substantially at the top end of its stroke with the air release valve opened and with the piston element about to be forced down to deliver its impact to the bottom fitting of the hammer.

Referring to the drawings, 11 designates the lower end of a section of well drilling pipe, said lower end being provided with the internally threaded conical bore 12 adapted to receive the externally threaded top end 13 of a rotary drilling tool 14. Designated generally at is an air hammer, according to the present invention, which is interposed between the drill pipe section 11 and the drilling tool 14 in a manner presently to be described.

The air hammer 15 comprises an annular top fitting 16 having an externally threaded conical tip 17 which is threadedly engageable in the conical bore 12 in the manner shown in Figure 1, whereby the top fitting 16 may be secured to the drill pipe section 11 in place of the conventional drilling tool 14. As shown, the top fitting 16 has the bore 18 which communicates with the bore 19 of the drill pipe section 11. Designated at 21) is a cylinder which is threadedly engaged on the depending lower portion 21 of the annular top fitting 16, and slidably positioned in the cylinder is a relatively massive piston 22,

atent 2 said piston being provided with a plurality of sealing rings 23 whereby the piston sealingly and slidably engages the inside surface of the cylinder 20.

Designated at 24 is a tubular piston rod which is threadedly engaged in the center portion of the top piston 22 and which is slidably received at its upper portion in the bore 18 of top fitting 16. A coiled spring 25 surrounds the tubular piston rod 24 and bears between the top surface of piston 22 and the bottom surface of the annular fitting 16 to exert a downward force on the piston 22.

The piston 22 is formed with a pair of downwardly

divergent passages

26, 26, said passages communicating at their top ends with the tubular rod 24 and communicating at their bottom ends with the space below the piston 22. Designated at 27 is an annular bottom fitting which has a reduced upper portion 28 threadedly engaged in the bottom end of cylinder 20 and which is formed with a vertical upstanding sleeve portion 29 whose top edge is engageable by the piston 22 to limit the downward move ment of said piston in the cylinder 20.

The bottom fitting 27 is formed with the axial, internally threaded conical bore 30 adapted to threadedly receive the externally threaded conical top end portion 13 of the drilling tool 14 in the manner illustrated in Figures 1, 5 and 6.

The bottom fitting 27 is formed with the threadedly cylindrical top cavity 31 located axially in the fitting and communicating with the outlet bore 32 of the fitting. The bore 32 communicates with the central bore 33 of the tool 14. The upstanding sleeve portion 29 of the bottom fitting 27 defines a cavity 34 having an annular bottom wall portion 35 surrounding the cylindrical recess 31 and defining a valve seat engageable by an annular valve element 36 mounted on a short cylindrical sleeve member 37. The sleeve member 37 is slidably engaged on a depending tubular bottom rod 38 threadedly secured in the central portion of the bottom of piston member 22 and being in axial alignment with said piston. A coiled spring 37 surrounds the depending bottom rod 38, the lower end of the coiled spring being secured to the annular valve element 36 and the top end of said coiled spring being secured to the bottom surface of the piston 22, whereby the tubular member 38 may be forced at times into the recess 31 and may move downwardly relative to the annular valve element 36 which is thus held sealingly against the valve seat 35 by the coiled spring 37. At other times, as for example, when the piston member 22 is elevated in the cylinder 20, as shown in Figure 6, the spring 37 lifts the valve element 36 off the valve seat 35.

The lower end of the depending tubular rod 38 is formed with an annular, outwardly projecting stop flange 4t) limiting downward movement of the sleeve rnemb 37 with respect to the tubular rod 33.

The piston member 22 is formed with a pair of upwardly

divergent air passages

41, 41 which communicate at their lower ends with'the interior of the depending tubular rod 33 and which communicate at their upper ends with the space 43 between the piston member 22 and the top fitting 21.

In operation of the hammer, compressed air, or similar fluid, is forced downwardly from bore 19 into bore 18 and through the depending piston rod 24 into

passages

26, 26, and thus into the space 34, with the piston member 22 in its lowered position, shown in Figure 1. The tluid builds up pressure in the space 34, causing the piston member 22 to be elevated against the force of the top spring 25 and against the tension of the lower spring 37. until the upward movement of the piston member 22 has developed sufiicient tension in the lower spring 37 to raise the annular valve element 36 oi? the valve seat 35. Figure 5 illustrates the position of the piston member 22 immediately prior to this condition.

As soon as the valve element 36 is lifted off the valve seat 35, the compressed fluid in the space 34 discharges through recess 31 and bore 32 into the bore 33 of the tool and at the same time flows upwardly through the depending bottom tube 38 and

passages

41, 41 into the space 43. The sudden reduction of pressure in space 34, combined with the application of fluid pressure to the top vof the piston member 22 by the fluid rapidly discharging into the space 43 develops a substantial down-ward force on the piston 22, which is combined with the force developed in the compressed upper spring 25, causing the piston member 22 to travel downwardly and to strike the top edge of the upstanding sleeve element 29 with considerable force.

This heavy impact is transmitted directly to the tool 14 by the bottom fitting 27. As the piston member 22 moves downwardly to deliver the aforesaid impact to the drilling tool, the annular valve element 36 engages the annular sleeve 35, sealing o'tf space '34 from recess 31, and allowing compressed air entering the space 34 from the

passages

26, 26 to again build up pressure in said space 34. This commences the next cycle of operation, similar to that above described, whereby repeated impacts are delivered to the drilling tool 14 responsive to the supply or compressed air to the hammer device through the drill pipe bore 19.

While a specific embodiment of an improved air hammer device for a well drilling apparatus has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those sklled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. In an air hammer for a well drilling apparatus, an annular top fitting adapted to be secured in the lower end of a drill pipe, a cylinder secured axially to said top fitting, an annular bottom fitting secured axially to the lower end of said cylinder, a hammer piston slidably mounted in said cylinder, a tubular piston rod connected to the top end of said piston and slidably engaged in said top fitting, spring means acting between said piston and top fitting, biasing the piston downwardly, a tubular bottom rod secured to the bottom end of said piston, an annular valve element slidably mounted on said bottom rod and being sealingly engageable on said bottom fitting, and spring means connecting said valve element to said piston, said piston being formed with a first air passage connecting said tubular top red to the space between the piston and the bottom fitting and with a second air passage connecting said tubular bottom rod to the space between the piston and said top fitting, whereby air under pressure entering said first named space builds up pressure to elevate the piston and to lift the valve element ofi the bottom fitting, allowing the piston to descend with hammer force on said bottom fitting because of the combined effects of the transmission of the compressed air to said second named space and the first named spring means.

f2. In an air hammer fora welldiilling'apparatus, an annular top fitting adapted to be secured in the lowerend of a drill pipe, a cylinder secured axially to said top fitting, an annular bottom fitting secured axially to the lower end of said cylinder, a hammer piston slidably mounted in said cylinder, a tubular piston rod connected to the top end of said piston and slidably engaged in said top fitting, a first coiled spring surrounding said piston rod and acting between said piston and top fitting, biasing the piston downwardly, a tubular bottom rod secured to the bottom end of said piston, an annular valve element slidably mounted on said bottom rod and being sealingly engageable on said bottom fitting, a second coiled spring connecting said valve element to said piston, said piston being formed with a first air passage connecting said tubular top rod to the space between the piston and the bottom fitting and with a second air passage connecting said tubular bottom rod to the space between the piston and said top fitting, whereby air under pressure entering said first named space builds up pressure to elevate the piston and to lift the valve element off the bottom fitting, allowing the piston to descend with hammer force on said bottom fitting because of the combined effects of the transmission of the compressed air to said second named space and the first named coiled spring.

3. In an air hammer for a well drilling apparatus, an annular top fitting adapted to be secured in the lower end of a drill pipe, a cylinder secured axially to said top fitting, an annular bottom fitting secured axially to the lower end of said cylinder, a hammer piston slidably mounted in said cylinder, a tubular piston rod connected to the top end of said piston and slidably engaged in said top fitting, a first coiled spring surrounding said piston rod and acting between said piston and top fitting, biasing the piston downwardly, a tubular bottom rod secured to the bottom end of said piston, said bottom fitting being formed with an axial recess formed and arranged to at times receive the lower portion of said tubular bottom rod and with an annular valve seat in its top end around said recess, an annular valve element slidably mounted on said bottom rod and being sealingly engageable on said annular valve seat, a second coiled spring surrounding said bottom rod and connecting said valve element to said piston, said piston being formed with a first air passage connecting said tubular top rod to the space between the piston and the bottom fitting and with a second air passage connecting said tubularbottom rod to the spacebetween the piston and said top fitting, whereby air under pressure entering said first named space builds up pressure to elevate the piston and to lift the valve element oil? the bottom fitting, allowing the piston to descend with-hammer force on said bottom fitting because of the combined efifects of the transmission of the compressed air to said second named space and the first named coiled spring.

References Cited in the file of this patent UNITED STATES PATENTS 1,264,318 McGrath Apr. 30, 1918 1,665,046 Tucker Apr. 3, 1928 1,828,604 Humphreys Oct. '20, 1931 2,403,582 Caudill July 9, 1946