Boring or penetrating the earth – Tool removable or insertable through or around driving or...
Reexamination Certificate
1998-05-19
2001-01-16
Lillis, Eileen D. (Department: 3673)
Boring or penetrating the earth
Tool removable or insertable through or around driving or...
C166S117500
Reexamination Certificate
active
06173796
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a sleeve for orientating a tool and in particular, but not exclusively, for orientating a running tool of a drilling system into a predetermined rotational position.
BACKGROUND OF THE INVENTION
It is sometimes necessary, for example in the drilling industry, to orientate one part of a system into a predetermined angular position relative to another part of that system. For example, in the Applicant's SYSTEM FOR IN SITU REPLACEMENT OF CUTTING MEANS FOR A GROUND DRILL described in International application no. PCT/AU94/00322 (WO 94/29567) a bit locking sleeve is used to orientate a tool in a predetermined angular position relative to a drive sub connected with a lower end of a core barrel. The bit locking sleeve described in WO 94/29567 is in the form of a cylindrical tube with a pair of opposing peaks extending from one end. The tool is used for carrying bit segments to and from the drive sub and is provided with latch dogs which extend radially from the body of the tool. When the tool is lowered through the core barrel, the latch dogs contact the side faces of the peaks causing the tool to rotate about its longitudinal axis relative to the drive sub. The purpose for this is to correctly align the tool with seats and splines formed in the drive sub so that the bit segments carried by the tool can be properly located in the drive sub.
Field trials of the above system have proved very successful. Nevertheless, it is thought that there is a potential for jamming to occur between the tool and the locking sleeve. This arises because the latch dogs in the tool are provided with a small degree of play. As a result of this, if the latch dogs were to strike the very top of both peaks at the same time, there is a possibility that both latch dogs will slide to the same side of each peak causing the tool to become jammed. In order to avoid jamming, it is critical to ensure that on every occasion the latch dogs slide on opposing sides of each peak.
SUMMARY OF THE INVENTION
The present invention was developed with a view to substantially reducing the likelihood of jamming occurring between the locking sleeve and tool of the above-mentioned system. However, it is to be understood that the present invention has application in systems other than those used in the drilling industry.
According to the present invention there is provided a sleeve for orientating a tool travelling through said sleeve into one of one or more predetermined rotational positions, said tool provided with at least one abutment surface, said sleeve comprising:
a substantially cylindrical member provided at one end with two or more tapered peaks extending in the axial direction of said cylindrical member, one of said peaks being higher than all other peaks;
whereby, in use, when a tool provided with at least one abutment surface travels through said sleeve, one of said abutment surfaces can contact said one peak and slide along one side of said one peak causing said tool to rotate about a longitudinal axis of said cylindrical member to orientate said tool toward said predetermined rotational position and wherein any other abutment surface can contact respective other peaks on a side distant said one side.
The number and width of the peaks is dependent on the number of predetermined rotational positions that the tool can take as well as the number of abutment surfaces (eg. latch dogs) on the tool. If there is only one protrusion on the tool for contacting the peaks then, to ensure correct angular alignment of the tool the sleeve can have one peak of a width of just less than 360°, of P
N
peaks of P
W
width where P
N
is the number of allowable predetermined positions and P
W
is slightly less than 360° divided by P
N
. For example, if the tool can take one of four (evenly spaced) predetermined positions and the tool has only one latch dog the sleeve can be provided with four peaks each of about 90° width. In the same example, if the tool has two evenly spaced latch dogs the sleeve can be provided with either two peaks each of about 180° width, or three or four peaks each of about 90°. In this example one peak should be higher than the others. Again in the same example if the tool has four evenly spaced latch dogs then the sleeve can be provided with one, two, three or four peaks each of a width of about 90°. The actual number and width of the peaks is not a critical aspect of the invention and can be varied to suit the application at hand and prevailing working conditions. What is important however is that when there is more than one peak on the sleeve, one of those peaks be higher than all others. It is advantageous but, as indicated above, by necessary, that the number of peaks be the same as the number of latch dogs/abutment surfaces provided on the tool.
Preferably said sleeve further comprises a land formed at a lowest point of each of said one or more peaks, each of said lands being adapted to receive respective ones of said abutment surfaces.
Preferably said lowest points are at the same level.
Preferably said sleeve is adapted for retention within a tubular member through which said tool can travel.
Preferably said sleeve is further provided with guiding means for guiding said sleeve to move linearly in the direction of said longitudinal axis of said tubular member while preventing rotation of said sleeve relative to said tubular member.
Preferably said guide means comprises one of a rail and channel formed on an outer peripheral surface of said sleeve, and the other of said rail and channel formed on an inner circumferential surface of said tubular member.
Preferably said sleeve further comprises releasable locking means for releasably locking said sleeve in at least one position relative to said tubular member so as to resist movement of said sleeve in an axial direction away from said at least one position.
Preferably said releasable locking means comprises at least one groove formed circumferentially about said outer circumferential surface of said sleeve and a radially resiliently expandable ring-like device adapted for retention in a circumferential groove formed in the inner circumferential surface of said tubular member, said ring-like device configured to sit proud of said inner circumferential surface when in a relaxed state;
whereby, in use, when said sleeve is moved linearly to a position where one of the grooves on the sleeve coincides with the groove on the tubular member, said ring-like device is partially seated in both grooves thereby locking said sleeve in said position.
Preferably the grooves on said sleeve are provided with sloping side surfaces leading from said outer peripheral surface to a base of said groove so that when said tool impacts on said sleeve, said ring-like device can be progressively expanded by said sloping side surfaces so that said ring-like device is moved out of said groove in said sleeve allowing said sleeve to move linearly along said tubular member.
Preferably the grooves in said tubular member have square or stepped sides to prevent the escape of said ring-like device therefrom.
REFERENCES:
patent: 1597143 (1926-08-01), Carter
patent: 1659769 (1928-09-01), Dodds
patent: 3306377 (1967-02-01), Johnson
patent: 4023630 (1977-05-01), Perkin et al.
patent: 4177867 (1979-12-01), Entner
patent: 4440222 (1984-04-01), Pullin
patent: 4651837 (1987-03-01), Mayfield
patent: 4834185 (1989-05-01), Braddick
patent: 5662182 (1997-09-01), McLeod et al.
patent: 5862859 (1999-01-01), Speed et al.
patent: 2115455 (1983-09-01), None
patent: 0 399 890 (1990-11-01), None
DHT Technologies LTD
Lillis Eileen D.
Singh Sunil
LandOfFree
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