GB2192215A

GB2192215A - Improvements relating to extraction device for pneumatically actuated drilling tools

Info

Publication number: GB2192215A
Application number: GB08707284A
Authority: GB
Inventors: Abraham Gien; Bernard L Gien
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-03-26
Filing date: 1987-03-26
Publication date: 1988-01-06
Anticipated expiration: 2007-03-26
Also published as: SE467009B; SE8701316L; GB2192215B; AU576694B1; SE8701316D0; GB8707284D0; CA1261819A

Abstract

The invention relates to an extraction device used for extracting pneumatically actuated impact tools and the like from boreholes. The device includes a carrier member (1), a reciprocable hammer (2), and a sleeve (13). The carrier 1 is adapted to be connected to a drill rod section. Reciprocation of the hammer relative to the carrier is used to effect extraction. Fluid passages (6), (16) are provided for conveying fluid under pressure through the device in order to cause the hammer to reciprocate and in so doing to strike a striking surface (8). <IMAGE>

Description

SPECIFICATION Improvements relating to extraction device for pneumatically actuated drilling tools This invention relates to a device for extracting pneumatically actuated impact tools and the like from boreholes.

"Down-the-hole" drilling tools are often lost, or are retrieved at a great expense, when they jam down the borehole wherein they are operating. This generally occurs due to excavated material lodging or packing around the drilling tools or around drill rods which supply the operating fluid to the drilling tool. Drill rod sections are in threaded engagement with each other and frequently attempts to extract the drilling tool by pulling on the drill rod simply cause the threads between individual drill rod sections to shear.

It is an object of this invention to provide means for assisting in the extraction of drill rods and drilling tools from boreholes.

According to the invention there is provided an extraction device for use in extracting a drill rod and drilling tools from a borehole comprising a hammer carrier adapted to be connected to a drill rod section, the carrier including a striking surface, a hammer reciprocably movable with respect to the carrier between a striking position adjacent the striking surface and a position removed therefrom, fluid flow paths in the carrier and/or the hammer adapted to convey activating fluid to cause reciprocation, momentum of the hammer on striking the striking surface in use being transmitted to the drill rod to urge the drill rod and drilling tool out of the borehole, and a sleeve encapsulating the hammer and defining upper and lower chambers between the inner walls of the sleeve, the hammer carrier, and the upper and lower ends of the hammer respectively, the fluid flow paths directing fluid in use to either the upper or lower chamber depending on the position of the hammer, at least one exhaust port being defined in the wall of the sleeve.

There will preferably be two exhaust ports, spaced apart in a vertical direction.

The accompanying drawing shows an extraction device according to the invention, the drawing being a cross-sectional side view of the device, the left hand side of the drawing showing the hammer in a striking position and the right hand side of the drawing showing the hammer in a position removed from the striking position.

Referring to the drawing, the extraction device shown includes a tubular carrier member 1 which carries a sleeve hammer 2, the hammer being movable between upper and lower stop formations numbered 3 and 4 respectively. The upper stop formation 3 is in the form of a collar secured to the carrier member 1 and the lower stop formation 4 is formed by an enlarged lower end of the carrier member. The upper stop formation defines a striking surface 8 for the hammer.

An axial bore 5 passes down the centre of the carrier member for conveying activating fluid. Lateral ports 6 are formed in the carrier member for conveying fluid from the axial bore 5 to the hammer 2. A constriction plug 7 limits the rate of excess fluid which can pass through the device.

A sleeve 13 is mounted to the carrier member and encapsulates the hammer. The sleeve has an inwardly directed flange 14 on the upper end thereof which locates in a recess 15 in the collar 3. The lower end of the sleeve engages with the enlarged end 4 of the carrier member.

The sleeve, carrier member, and hammer together define an upper chamber 10 and a lower chamber 9. The hammer has a recess 16 in the inner wall thereof for conveying fluid from the lateral ports 6 to the chambers.

The sleeve 13 has upper and lower exhaust ports, numbered 11 and 12 respectively.

Referring initially to the left hand side of the drawing, the hammer is shown in its striking position in striking contact with the striking surface 8. In this position fluid under pressure is conveyed through lateral port 6, through recess 16 to the upper chamber 10. This fluid will urge the hammer away from the striking surface 8. It will be noted that the lower chamber 9 is open to atmosphere through exhaust port 12 whilst the hammer is in this striking position, and the pressure in this lower chamber is thus low.

When the hammer is in the lower position as shown in the right hand side of the drawing, the lower chamber 9 is sealed and fluid under pressure is introduced into the lower chamber through lateral ports 6 and recess 16. The upper chamber, with the hammer in this position is open to atmosphere through upper exhaust port 11. The high pressure fluid will urge the hammer upwards towards the striking surface 8.

It will be appreciated that the hammer will automatically reciprocate between the two extreme positions resulting in drilling tools to which the device is secured being extracted from a drilling hole in use.

1. An extraction device for use in extracting a drill rod and drilling tools from a borehole comprising a hammer carrier adapted to be connected to a drill rod section, the carrier including a striking surface, a hammer recipro cably movable with respect to the carrier between a striking position adjacent the striking surface and a position removed therefrom, fluid flow paths provided in the carrier or the hammer or both for conveying activating fluid to cause reciprocation, so that, when in use, momentum of the hammer on striking the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements relating to extraction device for pneumatically actuated drilling tools This invention relates to a device for extracting pneumatically actuated impact tools and the like from boreholes. "Down-the-hole" drilling tools are often lost, or are retrieved at a great expense, when they jam down the borehole wherein they are operating. This generally occurs due to excavated material lodging or packing around the drilling tools or around drill rods which supply the operating fluid to the drilling tool. Drill rod sections are in threaded engagement with each other and frequently attempts to extract the drilling tool by pulling on the drill rod simply cause the threads between individual drill rod sections to shear. It is an object of this invention to provide means for assisting in the extraction of drill rods and drilling tools from boreholes. According to the invention there is provided an extraction device for use in extracting a drill rod and drilling tools from a borehole comprising a hammer carrier adapted to be connected to a drill rod section, the carrier including a striking surface, a hammer reciprocably movable with respect to the carrier between a striking position adjacent the striking surface and a position removed therefrom, fluid flow paths in the carrier and/or the hammer adapted to convey activating fluid to cause reciprocation, momentum of the hammer on striking the striking surface in use being transmitted to the drill rod to urge the drill rod and drilling tool out of the borehole, and a sleeve encapsulating the hammer and defining upper and lower chambers between the inner walls of the sleeve, the hammer carrier, and the upper and lower ends of the hammer respectively, the fluid flow paths directing fluid in use to either the upper or lower chamber depending on the position of the hammer, at least one exhaust port being defined in the wall of the sleeve. There will preferably be two exhaust ports, spaced apart in a vertical direction. The accompanying drawing shows an extraction device according to the invention, the drawing being a cross-sectional side view of the device, the left hand side of the drawing showing the hammer in a striking position and the right hand side of the drawing showing the hammer in a position removed from the striking position. Referring to the drawing, the extraction device shown includes a tubular carrier member 1 which carries a sleeve hammer 2, the hammer being movable between upper and lower stop formations numbered 3 and 4 respectively. The upper stop formation 3 is in the form of a collar secured to the carrier member 1 and the lower stop formation 4 is formed by an enlarged lower end of the carrier member. The upper stop formation defines a striking surface 8 for the hammer. An axial bore 5 passes down the centre of the carrier member for conveying activating fluid. Lateral ports 6 are formed in the carrier member for conveying fluid from the axial bore 5 to the hammer 2. A constriction plug 7 limits the rate of excess fluid which can pass through the device. A sleeve 13 is mounted to the carrier member and encapsulates the hammer. The sleeve has an inwardly directed flange 14 on the upper end thereof which locates in a recess 15 in the collar 3. The lower end of the sleeve engages with the enlarged end 4 of the carrier member. The sleeve, carrier member, and hammer together define an upper chamber 10 and a lower chamber 9. The hammer has a recess 16 in the inner wall thereof for conveying fluid from the lateral ports 6 to the chambers. The sleeve 13 has upper and lower exhaust ports, numbered 11 and 12 respectively. Referring initially to the left hand side of the drawing, the hammer is shown in its striking position in striking contact with the striking surface 8. In this position fluid under pressure is conveyed through lateral port 6, through recess 16 to the upper chamber 10. This fluid will urge the hammer away from the striking surface 8. It will be noted that the lower chamber 9 is open to atmosphere through exhaust port 12 whilst the hammer is in this striking position, and the pressure in this lower chamber is thus low. When the hammer is in the lower position as shown in the right hand side of the drawing, the lower chamber 9 is sealed and fluid under pressure is introduced into the lower chamber through lateral ports 6 and recess 16. The upper chamber, with the hammer in this position is open to atmosphere through upper exhaust port 11. The high pressure fluid will urge the hammer upwards towards the striking surface 8. It will be appreciated that the hammer will automatically reciprocate between the two extreme positions resulting in drilling tools to which the device is secured being extracted from a drilling hole in use. CLAIMS

1. An extraction device for use in extracting a drill rod and drilling tools from a borehole comprising a hammer carrier adapted to be connected to a drill rod section, the carrier including a striking surface, a hammer recipro cably movable with respect to the carrier between a striking position adjacent the striking surface and a position removed therefrom, fluid flow paths provided in the carrier or the hammer or both for conveying activating fluid to cause reciprocation, so that, when in use, momentum of the hammer on striking the striking surface is transmitted to the drill rod to urge the drill rod and drilling tool out of the borehole, and a sleeve encapsulating the hammer and defining upper and lower chambers between the inner walls of the sleeve, the hammer carrier, and the upper and lower ends of the hammer respectively, the fluid flow paths being arranged to direct fluid in use to either the upper or lower chamber depending on the position of the hammer, and at least one exhaust port being defined in the wall of the sleeve.

2. An extraction device as claimed in Claim 1, wherein there are at least two exhaust ports, vertically spaced apart, defined in the wall of the sleeve.

3. An extraction device substantially as hereinbefore described with reference to the accompanying drawing.