Handling: hand and hoist-line implements – Grapple – Well type
Patent
1998-12-07
2000-04-04
Kramer, Dean J.
Handling: hand and hoist-line implements
Grapple
Well type
294 8613, 294 8634, 166 98, E21B 3100
Patent
active
060451718
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a spear head assembly typically for use in ground drilling.
BACKGROUND OF THE INVENTION
Spear head assemblies are well known in the art of ground drilling and are typically used to provide a releasable connection between, a running tool or other apparatus which is required to be lowered into and/or retrieved from a ground drill or bore hole, and; a wire line located at the ground surface. An overshot is attached to one end of the wire line which is able to selectively grab and then release a spear head assembly.
The spear head assembly is often formed integrally with the running tool or apparatus although sometimes it is formed as a separate unit and then attached to the tool or apparatus. Known spear head assemblies typically include a fixed spear point which extends in the axial direction and points upwardly for engagement with the overshot.
A difficulty encountered with the use of known spear head assemblies is that they tend to act as a plug and substantially reduce the flow of mud or other drilling fluids along or through the running tool or apparatus to which they are attached, or the drill pipe or bore in which they are disposed.
A further difficulty with known spear head assemblies is that when the running tool or apparatus to which they are attached is removed from the ground, very high loads are placed on a shank portion of the spear point and a jar bar of the overshot. These loads can cause bending or breakage of the shank and jar bar. This increases the cost of drilling due to increased down time and equipment costs. Moreover, in the case of breakage, personal injury and death can result as very heavy pieces of drilling equipment can fall uncontrollably.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide a spear head assembly which is less restrictive to the flow of fluids when in use. It is a secondary object of the present invention to provide a spear head assembly which can reduce the loads placed on the weakest points of the spear point and/or an overshot coupled to the spear point.
According to the present invention there is provided a spear head assembly for connecting a running tool or other apparatus to a wire line, said running tool or other apparatus provided with a fluid flow path along or through which fluid can flow, said assembly comprising: first end adapted for coupling to said running tool or other apparatus, said main body portion being provided with an internal passage extending between first and second spaced apart openings, said first opening being at said first end; and, second end and adapted for coupling with said wireline; other apparatus and said wireline, said passage can communicate with said fluid flow path to allow fluid to flow through said fluid flow path.
Preferably said spear point is pivotally coupled to said main body portion to allow pivotal motion of said spear point about an axis substantially perpendicular to a longitudinal axis of said main body portion.
Preferably said assembly further comprises releasable locking means disposed within said passage for releasably locking said spear point in a first position.
Preferably when said spear point is in said first position said spear point is substantially co-axial with said longitudinal axis.
Preferably said releasable locking means comprises first and second complimentary and mutually engagable locking parts and means for biasing said first and second parts into mutual engagement, wherein said first part is provided on said spear point, said second part is supported by said main body portion, and said means for biasing is provided in one of said spear point and main body portion.
Preferably said first part comprises a recess formed in said spear point shaped to receive said second part.
Preferably said second part comprises a transversely extending pin supported in said main body part in a manner to allow limited movement thereof in the direction of said longitudinal axis.
Preferably said main body portion is prov
REFERENCES:
patent: 2333802 (1943-11-01), Lowrey
patent: 2705167 (1955-03-01), Layne et al.
patent: 2918323 (1959-12-01), Coffee
patent: 3173719 (1965-03-01), Ringler
patent: 4591197 (1986-05-01), Akkerman
patent: 5201814 (1993-04-01), Kitchell et al.
patent: 5392851 (1995-02-01), Arend
McLeod Gavin T.
Saver Chris
DHT Technologies Ltd.
Kramer Dean J.
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