Claims
- 1. An assembly of a centralizing device and a sensor or other operational tool, the device being for use down-well in maintaining the sensor or other operational tool in a location accurately centralized on the axis of the bore hole irrespective of the angular orientation of the device and tool at any given location, said device comprising
- an elongate body member having a longitudinal axis, which axis is, in use, maintained coincident with the longitudinal axis of the bore hole, the elongate body member having a plurality of spaced slots distributed around its circumferential surface, each said slot extending parallel to said longitudinal axis,
- a corresponding plurality of two-armed assemblies spaced around the longitudinal axis of the elongate body member, each arm each assembly being pivotally connected at a radially outer location at end portions of the arms, and capable of being accommodated substantially wholly within the envelope defined by the elongate body member when the arms are in a retracted configuration,
- radially outer pivots providing the pivotal connection at the radially outer end portions of the respective said arms,
- two slide blocks each having external cross-sections within the confines of the outer cross section of the elongate body member, each slide block defining a plurality of recesses corresponding to the number of two-armed assemblies, each said recess receiving an inner end portion of a said arm,
- means retaining the respective inner end portions of the arms in a respective one of the slide blocks,
- anti-friction members, each mounted at a said radially outer pivot of the two-armed assemblies and intended for contacting engagement with the surrounding structure of the bore hole.
- means at at least one end of the elongate body member for connecting it, when required, to an adjacent said operational tool or other component, and
- resilient means acting on at least one of said slide blocks to bias the two-armed assemblies outwardly from the body member so that the anti-friction members are always, in use, in contact with surrounding structure of the bore hole.
- 2. A device according to claim 1 wherein the slots of the elongate body member include relatively narrow portions at each end having a width sufficient to enable accommodation of the arms of the corresponding two armed assemblies and a relatively wider portion intermediate the narrow portions and having a width sufficient to accommodate at least partially those parts of the arms mounting the anti-friction members when the two-armed assemblies are in their retracted configuration.
- 3. A device according to claim 2, wherein the relatively narrower portions of the elongate slots are each substantially coincident, lengthwise of the elongate body member, with a hollow cylindrical portion of the elongate body member which hollow cylindrical portion accommodate internally a respective said slide block.
- 4. A device according to claim 3 wherein a central portion of the elongate body member corresponding substantially to the length of the relatively wider portion of each slot has a central bore having a diameter corresponding dimensionally substantially to the width of the narrower portions of each slot.
- 5. A device according to claim 1 wherein each slide block has one end serving as an abutment for the resilient means, and the other end portion of the slide block and an inner end portion of a corresponding arm of a said two-armed link assembly being conformed so to cooperate that under the action of the resilient means the said corresponding arm is caused to pivot outwardly, the force acting on the arm remaining substantially constant irrespective of the angular position by virtue of the operative conformation between the said end portions.
- 6. A device according to claim 5, wherein each said end portion is formed with at least one tooth.
- 7. A device according to claim 1, wherein each slide block has a boss in each recess which boss provides a location for a corresponding insert, the insert being secured to the block by a set screw engaged in a tapped bore of the boss.
- 8. A device according to claim 7 comprising means for retaining the inserts in each respective recess.
- 9. A device according to claim 8, wherein the retaining means comprises a retainer acting on each set screw, and a ring serving to retain the retainers on the elongate body member.
- 10. A device according to claim 1, wherein each resilient means is a stack of Belleville washers.
- 11. A device according to claim 1, comprising a spring mounted on the side of one arm of each of the two-armed assemblies, which spring serves to prevent the assembly from adopting an over-center position in a radial inwards direction.
- 12. A device according to claim 9, wherein the resilient means each directly abut a respective said ring of the retainer means.
- 13. A device according to claim 10, wherein the resilient means are of unequal stiffness.
- 14. A device according to claim 9, wherein each retainer has a portion thereof accommodated in a peripheral recess of the corresponding insert, the recess being undercut to receive a chamfered end edge of said portion of the retainer.
- 15. An assembly of a centralizing device and a sensor or other operational tool, the device being for use down-well in maintaining the sensor or other operational tool in a location accurately centralized on the axis of the bore hole irrespective of the angular orientation of the device and tool at any given location, said device comprising
- an elongate body member having a longitudinal axis, which axis is, in use, maintained coincident with the longitudinal axis of the bore hole, the elongate body member having a plurality of spaced slots distributed around its circumferential surface, each said slot extending parallel to said longitudinal axis,
- a corresponding plurality of two-armed assemblies spaced around the longitudinal axis of the elongate body member, each arm of each assembly being pivotally connected at a radially outer location at end portions of the arms, and capable of being accommodated substantially wholly within the envelope defined by the elongate body member when the arms are in a retracted configuration,
- radially outer pivots providing the pivotal connection at the radially outer end portions of the respective said arms,
- two slide blocks each having external cross-sections within the confines of the outer cross section of the elongate body member, each slide block defining a plurality of recesses corresponding to the number of two-armed assemblies, each said recess receiving an inner end portion of a said arm,
- each said slide block serving as an abutment for the resilient means at one end portion thereof, and having
- conformation means at the other end portion thereof, and each inner end portion of each arm of each said two-armed linkage having
- conformation means co-operating with corresponding said conformation means of the slide block
- the action of the resilient means on the hollow slide blocks being such that the conformation means of the slide blocks and of the arms causes the arms to pivot outwardly, the force acting on the arms being substantially constant irrespective of the angular orientation by virtue of the co-operating conformation means of the slide blocks and of the arms.
- 16. An assembly according to claim 15 wherein each said conformation means is in the form of at least one tooth-like member.
- 17. An assembly according to claim 15, wherein each slide block comprises several part cylindrical blocks angularly arrayed around the longitudinal axis of the body member.
- 18. An assembly comprising two centralizing devices for use down-hole in defining an axial alignment within the borehole, each said centralizing device comprising,
- an elongate body member having a longitudinal axis and having a plurality of spaced slots distributed around its circumferential surface, each said slot extending parallel to said longitudinal axis,
- a corresponding plurality of two-armed assemblies spaced around the longitudinal axis of the elongate body member, each arm of each assembly being pivotally connected at a radially outer location at end portions of the arms, and capable of being accommodated substantially wholly within the envelope defined by the elongate body member when the arms are in a retracted configuration,
- radially outer pivots providing the pivotal connection at the radially outer end portions of the respective said arms,
- two slide blocks each having external cross-sections within the confines of the outer cross section of the elongate body member, each slide block defining a plurality of recesses corresponding to the number of two-armed assemblies, each said recess receiving an inner end portion of a said arm,
- means retaining the respective inner end portions of the arms in a respective one of the slide blocks,
- anti-friction members, each mounted at a said radially outer pivot of the two-armed assemblies and intended for contacting engagement with the surrounding structure of the bore hole,
- means at at least one end of the elongate body member for connecting it to the other said centralizing device, and
- resilient means acting on at least one of said slide blocks to bias the two-armed assemblies outwardly from the body member so that the anti-friction members are always, in use, in contact with the surrounding structure of the bore-hole,
- the devices together defining an axial alignment between them.
Parent Case Info
This application is a continuation-in-part application based on Ser. No. 850,666 to R A Armell, filed Apr. 11, 1986, and now abandoned.
US Referenced Citations (9)
Foreign Referenced Citations (3)
Number |
Date |
Country |
1148995 |
Apr 1985 |
SUX |
2155519 |
Sep 1985 |
GBX |
2173533 |
Oct 1986 |
GBX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
850666 |
Apr 1986 |
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