Outrigger arm displacement control mechanism and method

Claim 2

A displacement control method, for use with a borehole tool having at least one radially extendable and retractable outrigger arm, for controlling the axial displacement of the outrigger arm relative to the tool as the effective extention of the arm from the tool changes, comprising: a) securing the respective ends of the arm to the tool at axially displaced locations, b) axially moving each end of the arm relative to the tool in response to increases and decreases in the radial extension thereof, and characterized by: c) guiding said arm end axial movement and causing corresponding predetermined rotation thereof about the exterior of the tool according and in response to said axial movement, and d) synchronizing the rotations of the two ends of the arm about the tool to move them substantially in unison and produce, for each radial extension of the arm, a predetermined rotated arm end position for each end thereof, and corresponsing related axial movements thereof, producing a defined axial displacement of the arm for each radial extension thereof.

Claim 3

The method of claim 1, characterized in that said securing ster comprises securing the respective ends of the arm with first and second respective collars mounted around the tool with the arm being connected at its ends, respectively, to the first and second collars.

Claim 4

The method of claim 1 or 2, characterized in that the synchronizing step includes forming and shaping the arms to be sufficiently transversely stiff to resist twisting spirally about the tool and to remain axially extended and aligned.

Claim 5

The method of claim 1, 2, or 3 characterized in that said guiding step further comprises producing the predetermined rotation of the arm in response to the axial arm end movement with a cam and race means, one mounted on the tool and the other moving with the end of the arm secured thereto, and the cam being captured in the race.

Claim 6

The method of claim 4 characterized in that the cam races are made substantially indentical to one another and of opposite hands to produce equal end displacements of the arm and maintain the mid-point of the arm at the same, single axial position along the tool independently of the radial extension of the arm.

Claim 7

The method of claim 4 or 5 characterized in that the guiding step comprises adjusting the cam race slopes to maintain the mid-point of the arm at the same axial position along the tool independently of the radial extension and retraction of the arm.

Claim 8

For use in a borehole tool having at least one radially extendable and retractable outrigger arm, a displacement control mechanism for regulating and controlling the axial displacement of the outrigger arm relative to the tool as the effective extension of the arm from the tool changes, characterized by: securing means for securing the respective ends of the arm to the tool at axially displaced locations, said securing means including means providing for relative axial movement of the ends of the arm in response to increases and decreases in the radial extension thereof, said securing means including guide means for guiding said arm end axial movement and causing corresponding predetermined rotation thereof about the exterior of the tool according and in response to said axial movement, and synchronization means for causing the two ends of the arm to rotate about the tool substantially in unison to synchronize the end rotations of the arm and produce, for each radial extension of the arm, a predetermined rotated arm end position for each end thereof, and corresponding related axial movements and displacements thereof, producing a defined axial displacement of the arm for each radial. extension thereof.

Claim 9

For use in a borehole tool having at least one radially extendable and retractable outrigger arm, a displacement control mechanism for regulating and controlling the axial displacement of the outrigger arm relative to the tool as the effective extension of the arm from the tool changes, characterized by: securing means for securing the respective ends of the arm to the tool at axially displaced locations, said securing means including means providing for relative axial movement of the ends of the arm in response to increases and decreases in the radial extension thereof, said securing means including guide means for guiding said arm end axial movement and causing corresponding predetermined rotation thereof about the exterior of the tool according and in response to said axial movement, and synchronization means for causing the two ends of the arm to rotate about the tool substantially in unison to synchronize the end rotations of the arm and produce, for each radial extension of the arm, a predetermined rotated arm end position for each end thereof, and corresponding related axial movements and displacements thereof, producing a defined axial displacement of the arm for each radial. extension thereof.

Claim 10

The mechanism of claim 7 characterized in that said securing means comprises first and second respective collars mounted around the tool with the arm being connected at its ends, respectively, to said first and second collars.

Claim 11

The mechanism of claim 7 or 8 characterized in that said synchronization means further comprises means forming and shaping said arms to be sufficiently transversely stiff to resist twisting spirally about the tool and to remain axially extended and aligned.

Claim 12

The mechanism of claim 7, 8, or 9 characterized in that said guide means further comprise cam and race means, one mounted on the tool and the other moving with the end of the arm secured thereto, said cam being captured in said race to produce said predetermined rotation of the arm in response to said axial arm end movement.

Claim 13

The mechanism of claim 10 characterized in that said cam races are made substantially indentical to one another and of opposite hands to produce equal end displacements of the arm and maintain the mid-point of the arm at the same, single axial position along the tool independently of the radial extension of the arm.

Claim 14

The mechanism of claim 10 or 11 characterized in that said cam races have slopes adjusted to maintain said magnet assembly centered over a single axial position along the tool during radial extension and retraction of the arm.

Claim 15

The mechanism of claim 10, 11, or 12 characterized in that said cam race slopes are constant, producing equal rotations for equal axial extensions of the arm ends.