Bore hole air hammer

Claim 2

In percussion drilling apparatus: a housing structure connectible to a drill string; an anvil in the lower portion of said housing structure and operatively connectible to a drill bit, said anvil having an exhaust passage; said housing structure including a first cylinder portion and a second cylinder portion therebelow of greater internal diameter than the internal diameter of said first cylinder portion, a hammer piston reciprocable in said cylinder portions for intermittently impacting against said anvil, said piston having an upper portion slidably reciprocable in said first cylinder portion and in sealed relation thereto, and a lower portion of greater diameter than said upper portion slidably reciprocable in said second cylinder portion and in sealed relation thereto; said upper piston portion having an effective cross-sectional area substantially equal to the internal cross-sectional area of said first cylinder portion; first means for directing a fluid medium under pressure into said first cylinder portion above said upper piston portion for action upon the full effective cross-sectional area of said upper piston portion, and into said second cylinder portion above said lower piston portion, for driving said hammer piston downwardly toward said mandrel; second means for directing the fluid medium under pressure into a lower portion of said housing structure for action upon said hammer piston to elevate said hammer piston in said housing structure; and exhaust passage means for exhausting substantially all of the fluid medium from said cyliNder portions above said upper and lower piston portions and from said lower portion of said housing structure into said exhaust passage of said anvil.

Claim 3

In apparatus as defined in claim 1; said first directing means including an inlet passage in said housing structure opening into said first cylinder portion through a side wall thereof.

Claim 4

In apparatus as defined in claim 1; said exhaust passage means including an exhaust passageway in an inner side wall of said second cylinder portion placed in communication by said hammer piston with the interior of said housing structure above said lower piston portion upon downward movement of said hammer piston in said housing structure.

Claim 5

In percussion drilling apparatus: a housing structure connectible to a drill string; an anvil in the lower portion of said housing structure and operatively connectible to a drill bit, said anvil having an exhaust passage; said housing structure including a first cylinder portion and a second cylinder portion therebelow of greater internal diameter than the internal diameter of said first cylinder portion, a hammer piston reciprocable in said cylinder portions for intermittently impacting against said anvil, said piston having an upper portion slidably reciprocable in said first cylinder portion and in sealed relation thereto, and a lower portion of greater diameter than said upper portion slidably reciprocable in said second cylinder portion and in sealed relation thereto; first means for directing a fluid medium under pressure into said first cylinder portion above said upper piston portion and into said second cylinder portion above said lower piston portion for driving said hammer piston downwardly toward said mandrel; second means for directing the fluid medium under pressure into a lower portion of said housing structure for action upon said hammer piston to elevate said hammer piston in said housing structure; and exhaust passage means for exhausting substantially all of the fluid medium from said cylinder portions above said upper and lower piston portions and from said lower portion of said housing structure into said exhaust passage of said anvil; said exhaust passage means including an exhaust passageway in an inner side wall of said second cylinder portion placed in communication by said hammer piston with the interior of said housing structure above said lower piston portion upon downward movement of said hammer piston in said housing structure, said exhaust passage means further including an exhaust passage in said hammer piston communicating with said exhaust passageway and said anvil exhaust passage.

Claim 6

In percussion drilling apparatus: a housing structure connectible to a drill string; an anvil in the lower portion of said housing structure and operatively connectible to a drill bit, said anvil having an exhaust passage; said housing structure including a first cylinder portion and a second cylinder portion therebelow of greater internal diameter than the internal diameter of said first cylinder portion, a hammer piston reciprocable in said cylinder portions for intermittently impacting against said anvil, said piston having an upper portion slidably reciprocable in said first cylinder portion and in sealed relation thereto, and a lower portion of greater diameter than said upper portion slidably reciprocable in said second cylinder portion and in sealed relation thereto; first means for directing a fluid medium under pressure into said first cylinder portion above said upper piston portion and into said second cylinder portion above said lower piston portion for driving said hammer piston downwardly toward said mandrel; second means for directing the fluid medium under pressure into a lower portion of said housing structure for action upon said hammer piston to elevate said hammer piston in said housing structure; and exhaust passage means for exhausting substantially all of the fluid medium from said cylinder portions above said upper and lower piston portions and from said lower portion of said housing structure into said exhaust passage of said anvil; said exhaust passage means including an exhaust passageway in an inner side wall of said second cylinder portion placed in communication by said hammer piston with the interior of said housing structure above said lower piston portion upon downward movement of said hammer piston in said housing structure, said exhaust passage means further including an exhaust passage in said hammer piston communicating with said exhaust passageway and said anvil exhaust passage.

Claim 7

In percussion drilling apparatus: a housing structure connectible to a drill string; an anvil in the lower portion of said housing structure and operatively connectible to a drill bit, said anvil having an exhaust passage; said housing structure including a first cylinder portion and a second cylinder portion therebelow of greater internal diameter than the internal diameter of said first cylinder portion, a hammer piston reciprocable in said cylinder portions for intermittently impacting against said anvil, said piston having an upper portion slidably reciprocable in said first cylinder portion and in sealed relation thereto, and a lower portion of greater diameter than said upper portion slidably reciprocable in said second cylinder portion and in sealed relation thereto; first means for directing a fluid medium under pressure into said first cylinder portion above said upper piston portion and into said second cylinder portion above said lower piston portion for driving said hammer piston downwardly toward said mandrel; second means for directing the fluid medium under pressure into a lower portion of said housing structure for action upon said hammer piston to elevate said hammer piston in said housing structure; and exhaust passage means for exhausting substantially all of the fluid medium from said cylinder portions above said upper and lower piston portions and from said Lower portion of said housing structure into said exhaust passage of said anvil; said first directing means including an impact passage in said piston opening at its upper portion into said first cylinder portion above said upper piston portion and at its lower portion into said second cylinder portion above said lower piston portion, said first directing means further including an inlet passage in said housing structure opening into said first cylinder portion through a side wall thereof and communicating with the lower portion of said impact passage upon upward movement of said piston in said housing structure.

Claim 8

In percussion drilling apparatus: a housing structure connectible to a drill string; an anvil in the lower portion of said housing structure and operatively connectible to a drill bit, said anvil having an exhaust passage; said housing structure including a first cylinder portion and a second cylinder portion therebelow of greater internal diameter than the internal diameter of said first cylinder portion, a hammer piston reciprocable in said cylinder portions for intermittently impacting against said anvil, said piston having an upper portion slidably reciprocable in said first cylinder portion and in sealed relation thereto, and a lower portion of greater diameter than said upper portion slidably reciprocable in said second cylinder portion and in sealed relation thereto; first means for directing a fluid medium under pressure into said first cylinder portion above said upper piston portion and into said second cylinder portion above said lower piston portion for driving said hammer piston downwardly toward said mandrel; second means for directing the fluid medium under pressure into a lower portion of said housing structure for action upon said hammer piston to elevate said hammer piston in said housing structure; and exhaust passage means for exhausting substantially all of the fluid medium from said cylinder portions above said upper and lower piston portions and from said Lower portion of said housing structure into said exhaust passage of said anvil; said first directing means including an impact passage in said piston opening at its upper portion into said first cylinder portion above said upper piston portion and at its lower portion into said second cylinder portion above said lower piston portion, said first directing means further including an inlet passage in said housing structure opening into said first cylinder portion through a side wall thereof and communicating with the lower portion of said impact passage upon upward movement of said piston in said housing structure.

Claim 9

In apparatus as defined in claim 5; said exhaust passage means including an exhaust passageway in an inner side wall of said second cylinder portion placed in communication by said hammer piston with said lower portion of said impact passage upon downward movement of said hammer piston in said housing structure, said exhaust passage means further including an exhaust passage in said hammer piston communicating with said exhaust passageway and said anvil exhaust passage.

Claim 10

In apparatus as defined in claim 5; said second directing means further including a return passage in said piston opening at its lower portion into said lower portion of said housing structure below said piston and at its upper portion into said first cylinder portion in communication with said inlet passage upon downward movement of said piston in said housing structure.

Claim 11

In apparatus as defined in claim 5; said second directing means further including a return passage in said piston opening at its lower portion into said lower portion of said housing structure below said piston and at its upper portion into said first cylinder portion in communication with said inlet passage upon downward movement of said piston in said housing structure; said exhaust passage means including an exhaust passageway in an inner side wall of said second cylinder portion placed in communication by said hammer piston with said lower portion of said impact passage upon downward movement of said hammer piston in said housing structure, said exhaust passage means further including an exhaust passage in said hammer piston communicating with said exhaust passageway and said anvil exhaust passage and with said housing structure below said piston.

Claim 12

In percussion drilling apparatus: a housing structure connectible to a drill string and having an inner cylinder portion and an outer portion surrounding said inner portion and spaced laterally therefrom to provide an annular air inlet passage therebetween, said outer portion extending below the lower end of said inner portion and having an inside diameter substantially greater than the inside diameter of said inner portion to provide an outer cylinder portion of greater internal diameter than said inner portion; an anvil in the lower portion of said housing structure and having an exhaust passage; a hammer piston reciprocable in said housing structure for intermittently impacting against said anvil, said piston having an upper small diameter portion slidably reciprocable in said inner cylinder portion and a lower large diameter portion slidably reciprocable in said outer cylinder portion below said inner cylinder portion; said inner cylinder portion having one or more side ports communicating said annular passage with the interior of said inner cylinder portion; said outer cylinder portion having an exhaust passageway in its inner side wall below said inner cylinder portion; said piston having an impact passage opening at its upper end into said inner cylinder portion and at its lower end into said outer cylinder portion; said piston having a return passage opening at its lower end into said outer cylinder portion below said piston and at its upper end into said inner cylinder portion below the upper end of said piston; said piston having an exhaust passage communicating said exhaust passageway with said anvil exhaust passage, said piston having means thereon cOacting with said housing structure to alternately communicate said impact passage with said one or more side ports and said exhaust passageway upon upward and downward movement, respectively, of said piston in said structure, said piston having means thereon coacting with said housing structure to alternately communicate said return passage with said one or more side ports and said piston exhaust passage upon downward and upward movement, respectively, of said piston in said structure.

Claim 13

In percussion drilling apparatus: a housing structure connectible to a drill string and having an inner cylinder portion and an outer portion surrounding said inner portion and spaced laterally therefrom to provide an annular air inlet passage therebetween, said outer portion extending below the lower end of said inner portion and having an inside diameter substantially greater than the inside diameter of said inner portion to provide an outer cylinder portion of greater internal diameter than said inner portion; an anvil in the lower portion of said housing structure and having an exhaust passage; a hammer piston reciprocable in said housing structure for intermittently impacting against said anvil, said piston having an upper small diameter portion slidably reciprocable in said inner cylinder portion and a lower large diameter portion slidably reciprocable in said outer cylinder portion below said inner cylinder portion; said inner cylinder portion having one or more side ports communicating said annular passage with the interior of said inner cylinder portion; said outer cylinder portion having an exhaust passageway in its inner side wall below said inner cylinder portion; said piston having an impact passage opening at its upper end into said inner cylinder portion and at its lower end into said outer cylinder portion; said piston having a return passage opening at its lower end into said outer cylinder portion below said piston and at its upper end into said inner cylinder portion below the upper end of said piston; said piston having an exhaust passage communicating said exhaust passageway with said anvil exhaust passage, said piston having means thereon cOacting with said housing structure to alternately communicate said impact passage with said one or more side ports and said exhaust passageway upon upward and downward movement, respectively, of said piston in said structure, said piston having means thereon coacting with said housing structure to alternately communicate said return passage with said one or more side ports and said piston exhaust passage upon downward and upward movement, respectively, of said piston in said structure.

Claim 14

In apparatus as defined in claim 9; and a sleeve in said anvil exhaust passage adapted to extend into said piston exhaust passage.

Claim 15

In apparatus as defined in claim 9; and a sleeve in said anvil exhaust passage adapted to extend into said piston exhaust passage in sealing relation to said piston; said piston being movable off said sleeve upon elevation of said piston in said structure to permit air below said piston to exhaust into said anvil passage.

Claim 16

In percussion drilling apparatus: a housing structure; an anvil extending into the lower portion of said housing structure; a hammer piston reciprocable in said structure above said anvil; means for reciprocating said piston in said housing structure for intermittently impacting said piston against said anvil; a connection between said housing structure and anvil including V-shaped external splines on said anvil, a member comprising a plurality of separate parts having V-shaped internal splines adapted to mesh with said external splines, said parts being movable laterally inwardly of said anvil toward each other to mesh said internal splines with said external splines, and means on said housing structure encompassing and retaining said separate parts in their lateral inward position.

Claim 17

In percussion drilling apparatus: a housing structure; an anvil extending into the lower portion of said housing structure; a hammer piston reciprocable in said structure above said anvil; means for reciprocating said piston in said housing structure for intermittently impacting said piston against said anvil; a connection between said housing structure and anvil including V-shaped external splines on said anvil, a member comprising a plurality of separate parts having V-shaped internal splines adapted to mesh with said external splines, said parts being movable laterally inwardly of said anvil toward each other to mesh said internal splines with said external splines, and means on said housing structure encompassing and retaining said separate parts in their lateral inward position.

Claim 18

In apparatus as defined in claim 12; said encompassing and retaining means including external threads on said parts meshing with companion internal threads in said housing structure.

Claim 19

In apparatus as defined in claim 12; the outer ends of said external splines lying on a circle of lesser diameter than the external diameter of said anvil above said splines.

Claim 20

In apparatus as defined in claim 12; said encompassing and retaining means including external threads on said parts meshing with companion internal threads in said housing structure, the outer ends of said external splines lying on a circle of lesser diameter than the external diameter of said anvil above said splines.

Claim 21

In apparatus as defined in claim 12; said separate parts consisting of two members each having an arcuate extent of about 180* and movable laterally inwardly of said anvil toward each other to mesh said internal splines fully with said external splines without interference from said external splines.

Claim 22

In apparatus as defined in claim 12; said external splines being circumferentially spaced uniformly from each other, said internal splines being circumferentially spaced uniformly from each other and movable laterally inwardly towards each other to mesh said internal splines fully with said external splines without interference from said external splines.

Claim 23

In apparatus as defined in claim 12; said external splines being circumferentially spaced uniformly from each other, said internal splines being circumferentially spaced uniformly from each other; said separate parts consisting of two members each having an arcuate extent of about 180* and movable laterally inwardly of said anvil toward each other to mesh said internal splines fully with said external splines without interference from said external splines.