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Publication numberUS3060588 A
Publication typeGrant
Publication dateOct 30, 1962
Filing dateMar 10, 1959
Priority dateMar 10, 1959
Publication numberUS 3060588 A, US 3060588A, US-A-3060588, US3060588 A, US3060588A
InventorsLanmon Ii C P, Saurenman Dean F
Original AssigneeSchlumberger Well Surv Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Borehole apparatus
US 3060588 A
Images(4)
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Description  (OCR text may contain errors)

4 Sheets-Sheet l C P LANMON ll, ETAL BOREHOLE APPARATUS Oct. 30, 1962 Filed March 10, 1959 ATTORNEY 0 EM m 2 ms ME. n 5 5 Oct. 30, 1962 c P LANMON 1:, ET AL 3,060,588

BOREHOLE APPARATUS Filed March 10, 1959 4 Sheets-Sheet 4 C P A awn/77,0)? Z7 flea/7 f-T Jaurenman v INVENTORJ wan A 7'7'ORNE Y United States Patent 3,060,588 BOREHULE APPARATUS C P Lanmon II, Friendswood, and Dean F. Saurenman,

Houston, Tex., assignors to Schlumberger Well Surveying Corporation, Houston, Tex., a corporation of Texas Filed Mar. 10, 1959, Ser. No. 798,547 8 Claims. (tli. 33-178) This invention relates to borehole apparatus and, more particularly, to new and improved measuring apparatus for engagement with the sidewall of a borehole.

Various borehole tools heretofore proposed have employed pad members, rigid arm members or spring type devices which project from a tool body into contact with the sidewalls of a borehole during ascent and descent of the tool or which are projected into contact with the sidewalls after the tool is at the bottom of the borehole and ready for ascent. Such tools generally have a relatively large diameter housing for power actuating and retracting devices of a complex nature to operate the arms and, quite naturally, increase the possibility of a malfunction or sticking of the tool in the borehole with resultant increased well costs.

Other borehole tools, such as a radioactivity tool are eccentrically positioned in the borehole and, to date, have no practical means for simultaneously measuring the diameter of the borehole while logging. Hence, a separate logging run is required to obtain a log of the borehole diameter. Thus, a need is presented for a simple reliable device for contacting the sidewalls of a borehole and this need is further accentuated in the case of eccentrically positioned tools where a log of the borehole diameter is desired.

Accordingly, it is an object of the present invention to provide new and improved apparatus for measuring a borehole parameter such as its diameter.

Yet another object of the present invention is to provide new and improved apparatus which aflords a simple and reliable means for obtaining an accurate and detailed log of the borehole diameter.

Another object of the present invention is to provide a new and improved unilaterally flexible arm member for use with borehole apparatus which may be passed through a borehole in either direction.

Another object of the present invention is to provide a new and improved arm member for use with borehole apparatus which may be passed through a borehole in either direction and is collapsible to the diameter of the borehole apparatus.

A still further object of the present invention is to provide a new and improved unilaterally flexible arm member for use with borehole apparatus which will permit re-runs of logs to be obtained without removing the tool from the borehole.

Another object of the present invention is to provide a new and improved self-contained apparatus which may be used in boreholes to measure diameter as an independent parameter and may be used in conjunction with other borehole apparatus.

Another object of the present invention is to provide an apparatus to measure a borehole parameter, such as diameter, which is not influenced by the angle or deviation of the borehole from vertical.

These and other objects of the present invention are attained by pivotally supporting, on the elongated body of a Well tool, a unilaterally flexible arm member which extends outwardly for engagement with the sidewall of a borehole. The unilaterally flexible arm member is articulated such that the arm member remains rigid or appoximately straight when subjected to bending forces acting in one direction but bends in response to oppositely directed forces. To obtain a measurement of borehole diameter, the arm member is biased with respect to the tool body to swing outwardly in a wall-engaging position and to be in a rigid condition so as to swing in response to borehole diameter variations as the tool is moved, for example, upwardly. Upon reverse movement of the tool, the arm member may yieldingly bend to a collapsed condition. Provision is made for resiliently urging the arm member towards its rigid condition to permit self-restoration from its collapsed condition, as when the tool is again moved in the original direction. The pivotal position of the arm member, when in its rigid condition and in engagement with the sidewall of the borehole, aflords a measure of the borehole diameter.

The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. 1 is an elevational view of apparatus embodying the invention when moving down the borehole;

FIG. 1A is a cross-sectional view taken along line 1A1A of FIG 1;

FIG. 2 is an elevational view similar to FIG. 1 showing the apparatus when moving up the borehole;

FIGS. 3A, 3B and 3C are upper, middle and lower portions, respectively, in longitudinal cross section through a portion of the apparatus of FIG. 1 with the arm member in its lower collapsed condition embodying the invention;

FIG. 4 is a view in cross section taken along line 4-4 of FIG. 3A;

FIG. 5 is a view in cross section taken along line 5-5 of FIG. 3B;

FIG. 6 is a view in cross section taken along line 66. of FIG. 3B;

FIG. 7 is a perspective view of a segment of the arm member;

FIG. 8 is an elevational view illustrating a second embodiment of the present invention;

FIG. 9 is a front elevational View illustrating a third embodiment of the present invention; and

FIG. 10 is a view partially in section of a modification of the wall-engaging element shown in FIG. 3B.

Referring now to FIG. 1, a borehole 11 traversing earth formations 12 receives a tool 13 which is shown in the condition it assumes during descent. Tool 13 is connected in the customary manner by an armored cable 14 to a spooling winch (not shown) at the surface of the earth which serves to raise and lower the tool in the usual manner.

Tool 13 generally includes a swivel mounting head 16 and a tubular caliper housing 17 which may be suitably interconnected at its lower end to other apparatus such as a radioactivity logging tool 18. For example, the logging tool 18 may be of the combination type aifording indications of both neutron and neutron-activated gamma radiation. Swivel head 16 may be of conventional con.- struction to permit the cable 14 to rotate relative to the caliper housing 17 and remainder of the tool 13 thereby eliminating any torque in the cable from being applied to the main portion of the tool. This also permits the-tool to follow preferential positions along the borehole on subsequent repeat logging runs.

An arm member 20 which embodies the present invention has one end portion suitably secured at pivot point 21 within an upper portion of the housing 17, the remain ing end portion extending through an elongated window or opening 22 (see FIG. 1A) into contact with the sidewall of the borehole 11. Arm member 20 is also retractable into the housing 17 to a collapsed position to facili- 3 tate passage through smaller diameter conduits or borehole sections.

While not shown, borehole 11 deviates from a vertical axi (as generally all boreholes do) so that tool 13 gravitates to the lowermost portion of the sidewall and, to further insure contact of the tool 13 with the sidewall, a pair of longitudinally spaced, hard rubber eccentering fingers 23 are provided in a lower portion of the tool below the arm member 20. Fingers 23 extend perpendicularly from the tool at an angle of 30 from a plane BB passing through the central axis of the tool and the line of contact 13a of the tool with the sidewall of the borehole (see FIG. 1A). Other sets of eccentering fingers (not shown) may be provided at variou positions on the tool body if so desired and, obviously, other types of eccentering devices, such as springs, or the like, may be employed. As shown in FIG. 1A, arm member 20 and the line of contact 13a effectively gauge the diameter of the borehole 11.

When the tool 13 is lowered in the borehole 11 (the direction shown by arrow A of FIG. 1), arm member 20 is flexed, being bent backwards towards the upper end of the tool, whereas, when the tool is raised towards the surface of the earth on a logging run (FIG. 2, arrow B), the arm member 20 is unidirectionally rigid with only its tip in contact with the sidewall of the borehole. Stated another way, arm member 20 has freedom of motion in a plane and is flexible only on one side of an axis in the plane. The construction and arrangement of the arm member 20 to permit this function will become more apparent in the explanation to follow.

Referring now to FIGS. 3A, 3B and 3C, housing 17 is comprised of an upper tubular section 17a, an intermediate section 17b and a lower tubular section 17c which are welded or otherwise suitably connected to one another to form a unitary construction.

Upper housing section 17a has an upper fluid chamber 25 formed between the inner walls of the housing section, an upper end plate member 26 and a lower end plate member 27. Similarly, lower housing section 17c (FIG. 3C) has a fluid chamber 25a formed between the inner walls of the section 17c, an upper end member 28 and a lower end member 29. Fluid chambers 25, 25a are interconnected by a fluid-tight elongated passageway 30 (see FIGS. 46) in the outer wall of the housing 17 and openings 31, 32 in chambers 25, 250, respectively. Passageway 30 is formed between the walls of an elongated slot 33 and an elongated cover plate member 34 welded in the slot, the passageway permitting electrical conductors 35 to be passed through housing 17b without exposure to drilling fluid.

The lower end member 27 of the upper chamber 25 has an opening 36 therein to permit a linkage system 37 to interconnect a potentiometer 38 in upper chamber 25 to a first arm 39 of a bell crank member 40 (FIG. 3B). To isolate chambers 25, 25a from the drilling fluid, a tubular rubber boot 41 is sealingly connected between the opening 36 and linkage 37. More specifically, the lower end of boot 41 is sealingly clamped about a connecting rod 42 of the linkage 37 by clamping means 43 and the upper end of the boot 41 is sealingly clamped to a tubular extension 44 by a clamp means 45, the extension 44 being sealingly received by the opening 36 in the end member 27.

Chambers 25, 25a and the boot 41 are filled with a relatively incompressible fluid 45 such as oil through access ports 46, 47, respectively, in housing sections 174, 170 so that the chambers are pressure balanced with respect to the hydrostatic pressure of the well fluid thereby facilitating movement of connecting rod 42. The portion of the rubber boot 41 facing window 22 of housing section 17b is protected from damage by a thin metal shielding plate 48 connected by pin connections 49 (see FIG. 4) near the upper end of the boot and a pin connection 49a 4 below the lower end of the boot (FIG. 3A), the plate 43 being suitably slotted at 51 to permit free movement of the connecting rod 42.

A tubular sleeve 50 fitted within the inner walls of housing section 17a and secured thereto by a plate 60 and screw means 61 provides a suitable mounting base for the potentiometer 38 and a portion of linkage 37. P0- tentiometer 38 includes an elongated potentiometer body 51, one end thereof pivotally connected to a post 52 on the sleeve 5%) at a pin connection 53, and a longitudinally slidable arm 54. Potentiometer 33 has electrical conductors 55 connected in an electrical circuit of a conventional recorder means (not shown) at the earths surface in a customary manner so that electrical signals are produced in the recorder in response to various longitudi' nal positions of slidable arm 54. Slidable arm 54 has its free end pivotally connected to a rigid link member 56 by a pin connection at 57, the link member 56 being pivotally connected to a post 58 on sleeve 50 by a pin connection at 59. The various pin connections 53, 57 and 59 thereby permit slidable arm 54 to move substantially parallel to the potentiometer body 51.

The linkage 37 thus far described has included the pivotal connection 57 of slidable arm 54 and link 56. The end of slidable arm 54 is also pivotally connected to the upper end of connecting rod 42 at a pin connection 65 while the lower end of connecting rod 42 (FIG. 3B) is pivotally connected between a pair of parallel plate members 39a, 39b (FIG 5) by a pin connection 66, the plate members comprising the first arm 39 of bell crank 40.

Bell crank 40 is pivotally mounted to the housing section 17b between a pair of mounting posts 67, 68 (see FIG. 5) by a pin 68a, the posts 67, 68 being fixed to the housing and abutting bell crank 40 so as to Prevent axial movement of the crank 40. A second crank arm 69 of bell crank 40 is comprised of a pair of parallel plate members 69a, 69b (FIG. 5) and is pivotally connected by a pin 70 to arm member 20 (FIG. 3B), the crank arm 69 being disposed angularly about 45 clockwise from the first crank arm 39. In the position shown, arm member 20 is retracted between the longitudinal edges 71, 72 of the window 22 (see FIG. 6), the window 22 extending longitudinally of the housing section 17b between the lower end member 27 of housing section 17a and the upper end member 28 of housing section 170. A tubular sleeve (not shown) may be received over the housing 17 and arm member 20 to retain the arm member 20 in the above-described position for transportation or storage purposes.

Also, in the retracted position of arm 20, the first arm 39 of crank 40 extends substantially perpendicular to a central axis through the housing 17. Bell crank 40 has a third crank arm 73 (FIG. 3B) comprised of a pair of parallel plate members 73a, 731; which are spaced angularly about 170 counterclockwise from the first crank arm 39. The crank arm 73 is connected to spring means 74- through a linkage 75 which serves to pivot the bell crank 40 in a counterclockwise direction thereby urging the free end portion of arm member 20 outwardly from housing section 171) into contact with the sidewall of the borehole.

Linkage 75 includes a connector rod 76 slidably received near its midpoint in a bore 78 of a pivot block 79 which is pivotally mounted by a pin 80 between a pair of posts 81, 82 secured to housing section 17b (see FIG. 6). Pin 80 also extends through an elongated slot 83 in connector rod 76 which permits relative longitudinal movement of the rod as well as a pivotal movement. The upper end of connector rod 76 is pivotally connected by a pin 84 to the third crank arm 73 while an opposite threaded end 85 receives threaded adjusting nuts 86. Compression spring 74 is disposed between the nuts 86 and pivot block 79.

The arm member 20 of the present invention includes a plurality of identically formed link members 87 aligned in an end-to-end substantially straight line relationship. Pins 88 serve to pivotally connect the link members to one another, the link 87a at the outer end of the arm being connected to a wall-engaging member 89. Link members 87 are generally channel shaped having polygonal shaped sidewalls 9t), 91 at right angles to a connecting Wall 92 (see FIG. 7). End surfaces 93, 94- terminate the lengthwise dimension of sidewalls 98, 91 and are adapted to cooperate, when the members 87 are interconnected to provide a rigid condition for the arm member when bending forces are applied in one direction to the arm. End surface 93 is formed from one end surface 92a of connecting wall 92 and portions of the adjoining end surfaces 99a, 91a of sidewalls 90, 91. Adjacent to end surfaces 99a, 91a are ears 95, 96 which project laterally and outwardly of end surface 93 and are separated therefrom by relief slots 97 (see PEG. 3B). Ears 95, 96 are oifset inwardly and parallel to one another a sutlicient distance so as to be slidably received within the sidewalls of an adjacent link member and permit abutment of end surface 93 of the one link member with end surface 94 of the adjacent link member. Pin receiving holes 98 are provided in ears 95, 96 and are arranged to register with piin receiving holes 99 located in sidewalls 99, 91 near the end surface 94, the axes of holes 98, 99 lying in a plane parallel to a segment 100 of connecting wall 92. Another segment 191 of connecting wall 92 is inclined outwardly and away from the plane through the central axesof holes 98, 99 so as to form a wedge-shaped, wallengaging portion having an apex 182 at the junction between segment 1-01 and end surface 94. End surface 93 isalso inclined very slightly towards ears 95, 96 so that, when link members 87 are pivotally connected by pins 88,arm 20 has a slight arc outwardly away from housing 17 (see FIG. 3B) to facilitate flexing of the arm in one direction.

A torsion spring 103 is received about each pin 88 and has end portions in contact with connecting walls 92 of the, adjacent link members to bias end surfaces 93, 9d of adjacent link members normally into abutment. Hence, counterclockwise bending moment applied to a pair of link members will increase the bias of spring 103 on the members so that when the bending moment is removed, the. link members will be biased back to their original inline position.

Wall-engaging member 89 is rigidly secured to the outer link member 87a by pins 851] and 104 (FIG. 3B), the forward portion 195 or" member 89 being tapered to an apex 1 06 which is adapted to slidably engage the sidewall of the formation when it is moved in one direction and to diginto the sidewall when it is moved in an opposite direction. Apex tee is arranged to lie on the arc of. the arm member 28 hence facilitating bending of the. arm.

As described previously, arm 28 is pivotally connected at; pin,78; to crank arm 69 and it will now be appreciated that. with this arrangement, a clockwise bending moment applied to the arm 20 about pin 70 will produce a pivotal movement of bell crank 48 since the adjacent end surfaces. 93,.94, of. each of the link members 88 are in abutment. thereby preventing relative movement between the link: members. On the other hand, if a counterclockwise bending moment is applied to the arm 28 about pin 70, each link member will pivot freely about the respective pivotpins 88 against the bias of the independent torsion springs 103.

Referring now to FIG. 2, if the tool is initially in the position shown, when the tool 13 is moved in a downward direction as shown by the arrow B, the apex 1126 OLWaII-engaging member 89 digs into the sidewall and pivots linkmember 8701 with respect to its adjacent link member so that the wall-engaging portion of link member 87 i1.digs intothe sidewall as shown in the dotted line construction. As the tool continues movement in a downwardldirection, each link member is successively pivoted and digs into the sidewall with its wall-engaging portion until the tool is in the position shown in FIG. 1 whereupon it may be lowered to any desired depth in the borehole, the wall-engaging portions being dragged along the sidewall.

To reverse the position of the arm member 20 in an operating position, the tool 13 is moved upward as shown by the dotted arrow A whereupon each link member is successively pivoted in a clockwise direction (shown in the dotted line construction), the wall-engaging portions of the link members providing a sufficient wall-engaging force to prevent movement of the link members upwardly relative to the sidewall of the borehole. Thus, the arm member 20 again assumes a rigid position as shown in FIG. 2.

With the arm 20 in a rigid position, as the tool is raised, the apex 106 of the wall-engaging member 89, through the link members 87', is urged against the sidewall of the borehole by the bell crank 40 and spring means 74. As the borehole diameter varies, the apex 106 follows the variations and, through the rigid arm member 24), pivots bell crank 40 thereby producing an electrical signal in potentiometer 38 in electrical linear response to vari ations in borehole diameter. For example, at a predetermined position of the arm, the electrical response will be at one value whereas if the measured borehole diameter decreases by one half, the electrical response will be one half of its original value.

Referring now to FIG. 8, the invention may be embodied in an arm member 20' comprised of a plurality of I tubular segments 109 pivotally connected to one another by pivot connections 110 at their uppermost, adjacent walls. One end of arm 20 is pivotally connected at 111 to the tool 13, the other end having a wall-engaging member 112. A coiled spring 113 received within the cylinders 109 provides the restoring force necessary to straighten the arm 20". As will be readily apparent, this apparatus functions similarly to the above-described embodiment.

In another embodiment shown in FIG. 9, an arm member 20" is comprised of a coiled spring 115 which is pivotally connected at one end to the tool 13 at 116 and has at its other end a wall-engaging member 117. The uppermost loops of the spring 115 are connected or secured to one another by suitable clamping means 118 or the like so that arm member 20" has a bending characteristic. Arm 22 also functions similarly to the abovedescribed embodiment.

The wall-engaging member 89 of sensing arm 29 may also assume a form 89' as shown in FIG. 10 wherein an, electrode 120 is connected to the end of a nonconductive member 121 and an electrical conductor 122 is passed through the nonconductive member and arm member 20 to appropriate electrical measuring circuits so that the electrode may serve to measure a parameter of the borehole or to provide electrical lubrication as described in Barreteau Patent No. 2,855,685.

It should also be apparent that while the foregoing embodiments illustrate only a single arm arrangement, more than one arm can be employed. Likewise the unilaterally flexible arm can be operated in an inverted fashion if so desired. In addition, it will be obvious, other linkage arrangements can be employed.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects, and thereforethe: aim. in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope ofthis invention.

What is claimed is:

l. Borehole apparatus for use in a borehole comprising: an elongated support adapted for passage through a borehole, an elongated unilaterally flexible arm disposed in a longitudinal plane passing through said support, means to pivotally connect a first end portion of said arm to said support, actuator means connected to said first end portion to urge the opposite end portion of said arm outwardly of said support into contact with the sidewall of the borehole, said arm including a plurality of elements arranged to lie on one side of an axis in said longitudinal plane, means to pivotally interconnect said elements, and means on cooperating portions of said elements to prevent relative rotation between said elements relative to said axis when a bending moment is applied to said arm in one direction yet permit relative rotation between said elements through said axis when a bending moment is applied to said arm in an opposite direction, and means to resiliently bias said elements normally to lie on said one side of said axis in said longitudinal plane.

2. Borehole apparatus for use in a borehole comprising: an elongated support adapted for passage through a borehole, an elongated unilaterally flexible arm disposed in a longitudinal plane passing through said support, means to pivotally connect a first end portion of said arm to said support, actuator means connected to said first end portion to urge the remaining end portion of said arm out wardly of said support into contact with the sidewall of the borehole, said arm including a plurality of elements arranged to align along an arcuate axis in said longitudinal plane, means to pivotally interconnect said elements, means on cooperating portions of said elements to prevent relative rotation between said elements when a bending moment is applied to said arm in one direction and said elements are along said arcuate axis yet permit relative rotation between said elements when a bending moment is applied to said arm in an opposite direction and means to resiliently bias said elements normally into a position along said arcuate axis, each of said elements having individual wall-engaging protrusions facing away from said arcuate axis.

3. In a well tool, a unilaterally flexible arm member comprised of a plurality of elements, means to pivotally connect said elements to one another, means on said elements to prevent relative rotation between said elements in one direction when said elements are in a substantially straight-line alignment yet permit relative rotation in an opposite direction, and means to resiliently bias said elements normally into said straight-line alignment.

4. In a well tool, a unilaterally flexible arm member comprised of a plurality of elements, means to pivotally connect said elements to one another, means on said elements to prevent relative rotation between said elements in one direction when said elements are in a predetermined alignment yet permit relative rotation in an opposite direction, and means to resiliently bias said elements normally into said predetermined alignment.

5. Borehole apparatus for use in a borehole comprising: an elongated support adapted for passage through a borehole, said support having an elongated window, an elongated unilaterally flexible arm disposed in a longitudinal plane passing through said support and adapted to be received in said support to have a portion thereof adapted to extend through said window, means to pivotally connect a first end portion of said arm to said support, actuator means connected to said first end portion to urge the remaining end portion of said arm outwardly of said support into contact with the sidewall of the borehole, said arm including a plurality of elements arranged to align along an arcuate axis in said longitudinal plane, means to pivotally interconnect said elements, means on cooperating portions of said elements to prevent relative rotation between said elements when a bending moment is applied to said arm in one direction and said elements are along said arcuate axis yet permit relative rotation between said elements when a bending moment is applied to said arm in an opposite direction and means to resiliently bias said elements normally into a position along said arcuate axis, each of 8 said elements having individual wall-engaging protrusions facing away from said arcuate axis.

6. Borehole apparatus for use in a borehole comprising: an elongated support adapted for passage through a borehole, an elongated unilaterally flexible arm disposed in a longitudinal plane passing through said support, means to pivotally connect a first end portion of said arm to said support, actuator means connected to said first end portion to urge the remaining end portion of said arm outwardly of said support into contact with the sidewall of the borehole, said arm including a plurality of elements arranged to align along an arcuate axis in said longitudinal plane, means to pivotally interconnect said elements, means on cooperating portions of said elements to prevent relative rotation between said elements when said elements lie along said arcuate axis and said remaining end portion of said arm is not subjected to a force along said arcuate axis yet permit relative rotation between said elements when said elements lie along said arcuate axis and said remaining end portion of said arm is subjected to a force along said arcuate axis.

7. In a well tool, a housing member comprised of up per, lower and intermediate sections, said upper and lower sections having fluid chambers, said intermediate section having an elongated window, a unilaterally flexible arm member secured to said intermediate section having a portion thereof adapted to extend outwardly of said section through said window, said intermediate section having a longitudinally extending passageway opening into said upper and lower chambers to permit electrical conductors to extend between said upper and lower sections, said chambers and passageway containing a relatively incompressible fluid, one of said chambers having an opening adjacent to said intermediate section and a flexible member secured to said intermediate section about said opening to enclose said fluid in said chambers and said passageway whereby said chambers may be pressure balanced with respect to pressure in said intermediate section.

8. In a well tool, a housing member comprised of upper, lower and intermediate sections, said upper and lower sections having fluid chambers, said intermediate section having an elongated window, a bell crank pivotally mounted in said intermediate section and having first and second arms, a unilaterally flexible arm member secured to a first arm of said bell crank, said arm member having a portion thereof adapted to extend outwardly of said section through said window, said intermediate section having a longitudinally extending passageway opening into said upper and lower chambers to permit electrical conductors to extend between said upper and lower sections, said chambers and passageway containing a relatively incompressible fluid, one of said chambers having an opening adjacent to said intermediate section, means for producing an electrical signal including relatively movable members, a connecting arm member connected to one of said relatively movable members and to the second arm of said bell crank for producing relative movement between said relatively movable members when said bell crank is pivoted, and a flexible member secured to said intermediate section about said opening and said connecting arm member to enclose said fluid in said chambers and said passageway whereby said chambers may be pressure balanced with respect to pressure in said intermediate section.

References Cited in the file of this patent UNITED STATES PATENTS 7,826 Sommers Dec. 10, 1850 166,938 Richardson Aug. 24, 1875 713,784 Mellor Nov. 18, 1902 745,357 Lanham Dec. 1, 1903 2,534,732 Smith Dec. 19, 1950 2,855,685 Barreteau Oct. 14, 1958

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3333466 *Dec 28, 1964Aug 1, 1967Seismograph Service CorpArticulated density logging tool
US3348314 *May 27, 1965Oct 24, 1967Dresser IndWell bore caliper
US6108921 *Jun 9, 1998Aug 29, 2000Pipetronix GmbhScraper for determining the position of pipelines
US7069775Sep 30, 2004Jul 4, 2006Schlumberger Technology CorporationBorehole caliper tool using ultrasonic transducer
US7131210Sep 30, 2004Nov 7, 2006Schlumberger Technology CorporationBorehole caliper tool
US7225881 *Jun 6, 2005Jun 5, 2007Bushnell David CPassive logging sonde auger tool
US8720607Mar 31, 2011May 13, 2014Smith International, Inc.Downhole tool having a friction stirred surface region
US20110240372 *Mar 31, 2011Oct 6, 2011Smith International, Inc.Article of manufacture having a sub-surface friction stir welded channel
Classifications
U.S. Classification33/544.3
International ClassificationE21B47/00, E21B47/08
Cooperative ClassificationE21B47/08
European ClassificationE21B47/08