# US 2009/0260889 A1 · Backhead and drill assembly with backhead

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- Number: US 2009/0260889 A1
- Document ID: US20090260889A1
- Status: Published application
- Kind: A1
- Application number: 12/494,126
- Filed: 2009-06-29
- Published: 2009-10-22
- Earliest claimed: 2005-11-03
- Assignees: Rockmore International, Inc.
- Inventors: Rainer S. Beccu
- Web page: https://patentgrep.com/patent/US20090260889A1

## CPC

- E21B 4/14: Fluid operated hammers
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

In representative embodiments, a backhead for a drill assembly comprises an elongate member having a proximal end connectible to a source of pressurized fluid, a side wall defining an axial bore and an open distal end. A portion of the bore extending proximally from the distal end has an inner surface defining a cylinder portion shaped to receive an axially movable piston. The axial bore also comprises a check valve receiving area shaped to receive a check valve and to separate, during normal operation when a check valve is received in the check valve receiving area, an inlet area extending proximally to the proximal end from the cylinder portion extending distally to the distal end. Various improvements in retaining the distributor and increasing flow efficiency are described.

## Claims

### Claim 1

A portion of a drill assembly operated by a supply of compressed fluid, comprising:
a backhead having a proximal end connectible to the supply, an axial bore and an open distal end having defined therein an integrated cylinder portion shaped to receive a piston member; and
a distributor positioned at least partially within the axial bore between the proximal end and the distal end, the distributor being removably secured to the backhead by a securing member accessible from an exterior surface of the backhead.

### Claim 2 (depends on 1)

The portion of a drill assembly of claim 1, wherein the securing member comprises a laterally extending pin inserted through at least one opening in the backhead.

### Claim 3 (depends on 1)

The portion of a drill assembly of claim 1, wherein the securing member comprises at least two laterally extending pins, each of the pins being inserted through one of a corresponding number of spaced-apart openings in the backhead.

### Claim 4 (depends on 1)

The portion of a drill assembly of claim 1, wherein the distributor comprises a check valve having a sealing member, a biasing member that biases the sealing member to a closed position and a distally extending guide portion.

### Claim 5 (depends on 1)

The portion of a drill assembly of claim 1, wherein the backhead includes an externally threaded portion to which a wear sleeve can be attached, and wherein the securing member comprises a laterally extending pin inserted through at least one opening in the backhead in the area of the threaded portion.

### Claim 6 (depends on 1)

The portion of a drill assembly of claim 1, wherein the piston member comprises a movable piston member.

### Claim 7 (depends on 6)

The portion of a drill assembly of claim 6, wherein the piston member comprises a reciprocable piston member.

### Claim 8

A portion of a drill assembly operated by a supply of compressed fluid, comprising:
a backhead having a proximal end connectible to the supply, an axial bore and an open distal end having defined therein an integrated cylinder portion, the backhead having passages extending between the axial bore and outer surface of the backhead;
a cylinder portion aligned with and in selective fluid communication with the backhead;
a hollow elongate wear sleeve surrounding the cylinder portion and connected to the backhead;
a piston housed by the wear sleeve and having a proximal end shaped to fit within the cylinder portion, the piston being slidably movable along the wear sleeve and the cylinder portion in response to compressed fluid conveyed through the backhead;
wherein when the drill assembly is in a drop open position, the proximal end of the piston is spaced apart from the cylinder portion and the wear sleeve.

### Claim 9 (depends on 8)

The portion of a drill assembly of claim 8, wherein, when the drill assembly is in the drop open position, the proximal end of the piston is longitudinally spaced apart from the cylinder portion.

### Claim 10 (depends on 8)

The portion of a drill assembly of claim 8, wherein, when the drill assembly is in the drop open position, an open annular space is defined between the proximal end of the piston and the wear sleeve.