US3316651A

US3316651A - Inclinometers

Info

Publication number: US3316651A
Application number: US427306A
Authority: US
Inventors: Josiah J Godbey
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-01-22
Filing date: 1965-01-22
Publication date: 1967-05-02
Anticipated expiration: 1984-05-02

Description

y 2, 1967 J. J. GODBEY 3,316,651

INCLINOMETERS Filed Jan. 22, 1965 3 Sheets-Sheet l KQEOEIVER p //7 v l /9 20 -TRANSMITTER 2/ I BATTERY M CE N.SWITCH 24 TRAN. RELAY I. 25 REV. RELAY .1 A CYCLETIMER 30 28 INERTIA WEIGHT I M I -COMMUTATOR Ski? EL. INTERMITTENT DRIVE 32 T R [Bk/x MO 0 @M 7 ANGLE-SENSING 37. f SWITCHES 35 INVENTOR ,3 Josiah J.- Godbey ATTORNEYS y 1967 J. J. GODBEY I 3,316,651

INCLINOMETERS Filed Jan. 22, 1965 5 sheets sheet 2 fQ/A 69 TRANSMITTER 2/ BATTERY 22 CENTRIFUGAL SWITCH 85 87 j RANsMlTTER 2 3 RELAY TIMING MOTOR as 8/ REVERSING 80 k f RELAY CYCLE TIMER COMMUTATOR INTERMITTENT -QBJALE TIMING MOTOR ANGLE SENSING SWITCHES ENERGlZiNG INVENTOR SWITCH JOSICIh J. Godbey ATTORNEYS y 1967 J. J. GODBEY 3,316,651

INCLINOMETERS Filed Jan. 22, 1965 3 Sheets-Sheet 3 56 O 0 INVENTOR Josiah J. Godbey ATTORNEYQf United States Patent 3,316,651 INCLINOMETERS Josiah J. Godbey, Richardson, Tex. (812 Nottingham Drive, Dallas, Tex. 75217) Filed Jan. 22, 1965, Ser. No. 427,306 13 Claims. (Cl. 33-205) This invention relates to new and useful improvements in inclinometers.

The invention is directed in particular to an inclinometer adapted to be mounted in the drill stem of a well drilling rig, desirably immediately above the drill bit for transmittal to the ground surface of signals indicating the degree of angularity of the well bore at the drill bit.

A principal object of the invention is to provide an improved inclinometer having a plurality of angle-sensing elements each adjusted to respond to a preselected angle, or any angles in excess thereof, to cause a signal to be transmitted to the ground surface, the angle-sensing elements being adjusted in sequence to increasing degrees of angularity by any desired increments so that the number of signals received at the ground surface indicates the angularity of the well bore, desirably adjacent the drill bit.

An additional important object of the invention is to provide an improved inclinometer for measuring the angularity of the well bore utilizing very sensitive anglesensing elements substantially free of frictional resistance and the malfunctioning of any one of which is precluded for affecting the functioning of the remaining angle-sensing elements.

A further object of the invention is to provide an improved inclinometer for measuring the degree of angularity of a well bore adapted to be mounted in the drill stem and which is held from operating while the drill stem is rotating, but which comes into immediate operation when the rotation of the drill stem is stopped and which sends a repeated series of angularity-indicating signals to the ground surface until rotation of the drill stern again commences or until a predetermined period of time has elapsed.

Yet another object of the invention is to provide an improved inclinometer for measuring the degree of angularity of a well bore in which, regardless of the angularity of the well bore, a signal is sent to the ground surface to indicate that the inclinometer is in operative condition.

Still another object of the invention is to provide as a sub-combination in an inclinometer for measuring the degree of angularity of a well bore an improved angle-sensing element or switch which is substantially free of frictional resitance and is extremely sensitive and accurate.

A further object of the invention is to provide as a subcombination in an inclinometer for measuring the de gree of angularity of a well bore an improved intermittent drive for converting continuous rotation to intermittent rotation, the drive having a very positive action and producing sequenial increments of motion of uniform magnitude.

An additional object of the invention is to provide an improved inclinometer for measuring the degree of angularity of a well bore which is battery operated, requiring no connection to the ground surface other than through the drill stem and which is so arranged as to minimize the load or drain upon the battery or batteries.

The invention comprises a housing adapted to be securely positioned in the lower end of the drill stem adja cent the drill bit with provision for circulation of drilling fluid through the drill stem and around the housing to the drill bit, the housing containing a plurality of anglesensing elements which function at preselected angles and 3,316,651 Patented May 2, 1967 are adjusted to respond to increasing degrees of angularity in sequence, a motor driving through an intermittent drive, a commutator which causes a series of pulse signals to be sent to the ground surface from an acoustic transmitter in accordance with which of the angle-sensing elements are activated, a centrifugal switch for deenergizing the inclinometer whenever the drill stem is rotating, a cycle timer driven by the motor for moving in one direction to close a reversing switch to reverse the motor and drive the cycle timer in the opposite direction to open a switch which stops the motor, and an inertial switch associated with an inertia weight which causes the inertial switch to close whenever rotation of the drill stem again commences together with suitable batteries for powering the motor and the acoustic transmitter.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein an example of the invention is shown, and wherein:

FIG. 1 is a vertical elevational View, partially broken away to illustrate schematically the structure and arrangements of an inclinometer constructed in accordance with this invention,

FIG. 2 is a horizontal, cross-sectional view, taken on the line 22 of FIG. 1,

FIG. 3 is an enlarged, fragmentary, side elevation of the inertial switch and the related inertia weight,

FIG. 4 is a horizontal, cross-sectional view, taken upon the line 4-4 of FIG. 3,

FIG. 5 is a horizontal, cross-sectional view, taken upon the line 5-5 of FIG. 3,

FIG. 6 is a wiring diagram of the inclinometer,

FIG. 7 is an enlarged, fragmentary, vertical, sectional view of one of the angle-sensing elements showing the same in a vertical or upright position,

FIG. 8 is a view similar to FIG. 7 showing the anglesensing element tilted at an angle of ten degrees,

FIG. 9 is a fragmentary, vertical, cross-sectional view. partly in elevation, illustrating the intermittent drive, and

FIG. 10 is a horizontal, cross-sectional view taken upon the line 10-1ti of FIG. 9.

In the drawings, the numeral 10 designates a conventional wel-i casing downwardly through which extends the usual drill pipe or drill stem 11 carrying upon its lower end a drill collar 11' and a well drill bit (not shown). In the lower portion of the drill collar 11', desirably closely above the drill bit, an inclinometer 12 is mounted in any suitable or desirable fashion as by confinement between a lower internal shoulder 13 provided on the inner wall of the drill collar and an upper internal ring or shoulder 14 positioned interiorly of the drill collar in any suitable fashion as by threading thereinto. Thus inclinometer 12 and drill collar 11' are readily removable from the drill string assembly as a unit. The inclinometer includes an elongate sealed housing 15 having a spider 16 at its lower end for engaging the shoulder 13 and a similar spider 17 at its upper end for engaging the upper shoulder 14. The housing 15 has an outside diameter somewhat less than the inside diameter of the drill collar 11' to form an annulus 18 through which drilling fluid may pass downwardly through the drill collar to the drill bit, it being 19 with a conventional acoustic transmitter or generator 20 in close and intimate contact therewith. Below the transmitter is a battery or batteries 21 for powering the inclinometer and below that a conventional centrifugal switch 22 of the type readily available adapted to open when the inclinometer is rotating with the drill collar 1-1 and to close when rotation ceases. Below the centrifugal switch 22 is a transmitter relay 23 and a reversing relay 24, both of which will be described in further detail.

Below the reversing relay is a reversing switch 25 and a cycle timer 26 which also will be described in a greater detail. Following the cycle timer is an inertia weight 27 carrying an inertial switch 28, a driven shaft 29 extending through the inertia weight having its screwthreaded upper portion 30 thereabove for operating the cycle timer. A driving shaft 31 extends upwardly from a timing motor 32 to an intermittent drive means 33 from which the driven shaft 29 extends upwardly through a commutator or rotary switch 34 to and through the inertia weight '27. Below the motor 32 are disposed a plurality of angle-sensing elements or anglesensing switches 35 which extend to the lower end of the housing 15, an on-Off actuating switch 36 being provided at the lowermost end of the housing. The switch 36 functions as a master switch so that the power supply need not be turned on until the drill string is ready to be lowered into the well bore, and so that the unit can be shut off completely at any time it is not being used, is being transporated from one location to another, and the like.

Four longitudinal supporting or chassis rods or bars 37 are equally spaced about the inner periphery of the housing 15 and serve as support or guide members for the various components of the inclinometer.

The cycle timer 26 is shown in FIGS. 1 and 6 and includes a travelling head 38 in screwthreaded engagement with the screwthreadcd portion 30 of the driven shaft 29, the head 38 carrying an actuating pin 39 eccentrically offset from the shaft 39 and projecting above and below the head. As shown in FIG. 2, the head 38 is formed with spaced peripheral notches 40 slidingly engaging the frame members 37 so that the head 38 may slide longitudinally upwardly and downwardly on the rod 37, but is held by the rods against rotation. As the timing motor 32 is driven in one direction, the screwthreaded portion 30 of the shaft will be revolved, moving the head 36 upwardly until the pin 39 closes the normally-open reversing switch 25. Upon the reversing of the motor 32, the head will travel downwardly until the pin 39 opens the normally-closed inertial switch 28, thus completely deenergizing the entire circuitry.

The commutator is of more or less conventional structure having a sweeper arm or brush 41, and a plurality of contacts 42 adapted to he engaged momentarily by r the sweeper arm, there being provided one more contacts than there are angle-sensing switches 35. The sweeper arm of the commutator 34 is driven intermittently through the intermittent drive 33, the sweeper arm 41 dwelling between adjacent contacts at time of rest and sweeping past or over each of the contacts only momentarily as the arm advances or indexes from one position to the next. Should the commutator sense a closed circuit through one of the angle-sensing switches 35, the momentary small current operates the transmitter relay 23 in an impulse manner, and the latter in turn closes to supply a momentary, relatively large current to the transmitter 20. Thus, the sweeper arm 41 is closed only very momentarily with any one of the contacts 42 and the load or drain upon the battery 21 is thus minimized.

The inertial switch assembly is shown in FIGS. 3, 4, and and includes a bottom support plate 43 mounted upon the rods 47 and supporting the inertia weight 27 which is formed with enlarged, longitudinal, spaced grooves 44 in its outer surface receiving the rods 37 and which, being wider than the rods 37, permits the inertia weight to undergo limited rotational movement about the shaft 29. The weight 27 is received upon the shaft 29 upon a bushing 45 through which the shaft 29 extends, the bushing having a foot portion 46 :by means of which the weight is supported upon the upper surface of the plate 43. The inertial switch 28 is mounted upon the upper end of the inertia weight 27 having normallyclosed contacts 47 with a tab 48 extending therefrom for engagement by the finger 39.

A pin 49 projects downwardly from the lower end of the inertia weight 27 through an arcuate slot 50 cut in the support plate 43, the plate 43 carrying a coiled tension spring 51 constantly urging the inertia weight to rotate through a limited arc in the direction of rotation of the drill stem so that when the inclinometer has been at rest with the drill stem not rotating and rotation is then resumed, the inertia weight 27 will tend to remain stationary for a moment so that the bars 37 move momentarily to the opposite ends of the grooves 44 against the influence of the spring 51, thus misalining the pin 39 and the tab finger 48. As will appear more fully hereinafter, if the pin 39 is in engagement with the tab 48 at this time and has depressed the same to open the contacts 47, this rotational movement will cause the tab 48 to slip from beneath the pin 39 allowing the contacts 47 to reclose and preventing the finger 39 from reopening them until it has again moved upwardly and again downwardly through its entire stroke. After only a short period of rotation, the spring 51 tends to return the inertia weight 27 to the position shown in FIG. 5, but the pin 39, by engaging the side rather than the top of the tab 48, will not reopen the contacts 47.

The intermittent drive means is shown in FIGS. 9 and 10, the longitudinal bars 37 forming the supporting means and carrying a first transverse support plate or means 52 through which the driving shaft 31 extends. The driving shaft terminates at the upper face of the support plate 52 in an enlarged head 53 having an offset or eccentrically positioned driving pin 54 projecting upwardly from the plate 52. A snap-ring 53' holds the shaft 31 in the plate 52. A second transverse support plate or means 55 is also carried by the bars 37 in spaced relationship above the plate 52.

A circular disk 56 is positioned immediately beneath the plate 55 and is provided with a central hub 57 extending upwardly in rotatable relationship through the plate 55, the hub 57 having a longitudinal bore 58 for receiving the driven shaft 29, the latter being secured in the bore by a suitable set screw 59. A plurality of driven pins 60, equally spaced from one another, are arranged in a circle around the periphery of the disk 56 and project downwardly toward the first support plate 52. A snap ring 61 engaging the hub 57 prevents downward movement of the hub and the disk 56. An elongate link 62 has one end pivotally mounted upon the driving pin 54 as shown in FIG. 10 and is provided with an elongate slot 63 intermediate its ends receiving a fixed pin 64 projecting upwardly from the plate 52 outside of the head 53 and thus eccentrically with respect to the shaft 31. The outer end of the link 62 carries a longitudinal notch 65 of a width suflicient to receive the pins 60, the outer end of the notch 65 being divergent as shown at 66.

In the operation of the intermittent drive, the shaft 31 and head 53 are driven at a constant uniform speed by the timing motor 32, and thus, the driving pin 54 is caused to move constantly in a circular path about the axis of the shaft 31. The link 62 having its inner end pivotally connected to the driving pin 54 is thus caused to move in a circular path, and by reason of the engagement of the fixed pin 64 in the slot 63, the outer end of the link 62 is caused to move in a circular or elliptical path. By reason of such movement, the link withdraws from engagernent with one of the pins 60, swings laterally and moves into engagement with the next successive pin 68 and then reverses its movement to move that pin 68 and therefore the disk 56 through a limited arc. The disk 56 is rotated only when the link is engaging one of the pins 60, and consequently, the disk 56 and therefore the hub 57 and driven shaft 29 are rotated in small angular increments with absence of motion between such rotational movements. The sweeper arm 41 or the commutator or rotary switch 34 is thus moved in small angular increments over the contacts 42, the dwelling periods of the sweeper arm 41 being between adjacent contacts rather than in engagement therewith.

The angle-sensing switches are an important feature of the invention and are shown in FIGS. 7 and 8 of the drawings. Here again, the bars 37 form the supporting member and carry an upper support means or plate 67 and a lower support means or plate 68 spaced below the plate 67. A support pin 69 is adjustably mounted in the lower plate 68, as by screwthreaded engagement therewith, for vertical adjustment upwardly and downwardly in the space between the two support plates. A locking nut 70 serves to secure the pin in its adjusted position. A hollow, frusto-conical first contact member 71 is pivotally supported upon the upper end of the pin 69, the hollow interior of the member 71 being conical and closed at its upper end by a bearing insert 72 which may, if desired, be of hardened metal. The lower exterior of the member 71 is bevelled downwardly and inwardly, as shown at 69', to provide ample clearance between the member and the bars 37; and the upper end 73 of the pin 69 is conical, there being provided a very small bearing ball 74 between the upper end of the pin 69 and the insert 72. The bearing ball 74 may be secured to either .the insert 72 or the upper end of the pin 69, and it will be noted that the contact area between the pin 69 and the first contact member 71 is extremely small in proportion to the mass of the member 71. The contact member 71 instantly and accurately tilts upon the pin 69 in accordance with the tilting of the inclinometer.

For preventing dislodgment of the first contact member 71 from the pin 69, the upper support plate 67 is provided with a vertically adjustable stop pin 75 extending downwardly from the plate 67 toward the first contact member 71 and being vertically adjustable toward and away from the member 71 in any suitable fashion as by screwthreaded engagement with the plate 67. A lock nut 76 holds the pin 75 in its adjusted position in which it is sufficiently close to the upper end of the first contact member 71 as to prevent its dislodgment from the pin 67, yet far enough from the member 71 as not to come in engagement therewith.

A second contact member 77 in the form of an annular ring mounted interiorly of the bars 37 surrounds the medial portion of the member 71 and is supported from the plate 67 and the bars 37 by a cylinder 78 formed of a suitable dielectric or electrical insulating material. Thus, the first and

second contact member

71 and 77, respectively, are electrically insulated from one another when the inclinometer is in a vertical position.

In FIG. 8 is shown the result of tilting the inclinometer through an angle of the first contact member 71 functioning to remain in a vertical or upright position so that the second contact member 77 is swung into engagement with the member 71 and an electrical circuit is completed.

The angle-sensing switches are readily adjusted for the completion of an electrical circuit at any desired degree of angularity and obviously may be modified dimensionally for functioning at very small angles or relatively large angles. Thus, a series of the angle-sensing switches may be adjusted to close circuits at succesive degrees of angularity or in successive fractions of a degree.

In the position of the first contact member 71 shown in FIG. 7, the electrical circuit is completed at an angularity of 10 degrees, but by adjusting the pin 69 upwardly and correspondingly adjusting the stop pin with respect to the upper end of the member 71, the degree of angularity at which the circuit is completed will be progressively decreased until an angle of one-half degree or so will cause the circuit to be closed. In this manner, a series of the angle-sensing switches may be progressively adjusted to close progressively in one degree or one-half degree increments, or in other desired increments, all of which will be explained more fully hereinafter.

The wiring diagram of the inclinometer is shown in FIG. 6 of the drawings, the battery or batteries 21 having their negative terminal connected through the centrifugal switch 22 to the normally-closed inertial switch 28 and then to a negative lead 79. The armature coil 80 of the timing motor reversing relay 24 is in parallel with a suppressing diode 81 and is connected between the lead 79 and the normally-open reversing switch 25. The other side of the switch 25 is connected to a positive lead 82 which is connected through the energizing switch 36 to the positive terminal of the batteries 21.

The reversing relay 24 includes a first double-throw, single-pole switch 83 having its normally-closed contact connected to the lead 79, its armature connected to one terminal of the timing motor 32 and its normally-open contact connected to the positive lead 82. A second double-throw, single-pole switch 84 in the relay 24 has its normally-closed contact connected to the positive lead 82, its armature connected to the second terminal of the motor 32, and its normally-open contact connected to the negative lead 79. Thus, electrical power for the motor 32 is supplied through the two

switches

83 and 84, and upon energization of the reversing relay, the polarity of the electrical power supplied to the timing motor will be reversed to cause the motor to reverse. Relay 24 also includes a single-throw, single-pole switch 85 having its normally-open contact connected to the positive lead 82 and its armature connected to the positive side of the armature coil 80, this third switch 85 thus becoming a holding switch which, when closed by energization of the relay 24, supplies a holding current to the armature coil' 80 to maintain the relay 24 energized.

The transmitter relay 23 has its armature coil 86 connected in parallel with a suppressing diode 87, one side of the coil being connected to the negative lead 79 and the other side being connected to the wiper arm 41 of the commutator switch 34. The transmitter relay 23 includes a single-pole, single-throw switch 88 having its normally-open contact connected to the negative lead 79 and its armature connected through the energizing coil 89 of the acoustic transmitter 19 to the positive lead 82. Thus each time the transmitter relay 23 is energized, the coil 89 of the transmitter will be energized to send a pulse signal of an acoustical nature to the ground surface through the drill stem and/or casing. At the ground surface, the pulse signal, or series of pulse signals, is detected by the receiver 90 (FIG. 1) and either noted audibly, visibly and/or electrically being recorded in conventional fashions if so desired.

In the particular embodiment of the invention shown in FIG. 6, there are provided ten of the angle-sensing switches 35, the first being adjusted to close a circuit at an inclination of one-half degree, the second at an inclination of one degree, the third at an inclination of one and a half degrees, and so on by one-half degree increments up to the final switch which closes at an inclination of five degrees. Thus, if the well bore is inclined at an angle of one-half degree, only the first switch will be closed, whereas if it is inclined at an angle of two degrees, the first four angle-sensing switches Will be closed.

The first contact members 71 of the series of anglesensing switches 35 are connected to the positive lead 82, and the second contact members 77 of the switches are connected individually to separate ones of the contacts 42 of the commutator 34. In this manner, whichever one of the angle-sensing switches 35 that may be closed at a particular moment will be placing certain ones of the contacts 42 in connection with the positive lead 82, and accordingly, as the brush 41 sweeps around and over the contacts 42, one or more pulses will be supplied from the energized contacts to the brush 41 and hence to the coil 86 of the transmitter relay 23 to energize the acoustic transmitter 19 in a pulsewise fashion. One terminal of the commutator, the terminal marked by the numeral 1, is directly connected to the positive lead 82, and accordingly, each time the commutator brush 41 revolves through 360, at least one pulse will be generated by the transmitter 19 to indicate at the ground surface that the inclinometer is operating properly. Accordingly, when a series of pulses is received at the ground surface, the number thereof will be diminished by one to ascertain how many of the angle-sensing switches are closed. Following this procedure, if seven pulses are observed at the ground surface, it will be known that six of the anglesensing switches are closed since one pulse is always transmitted even though the well bore is exactly vertical, the six pulses indicating that the well bore at the moment is at an inclination of 3.

In the operation of the inclinometer, the switch 36 is closed and the entire .assembly positioned in the drill stem as shown in FIG. 1. As the drill stem is lowered to drilling position, there may be no rotation thereof, and hence, the inclinometer may run through a single cycle at this time. At the end of the cycle, however, the inertial switch 28 will be opened and the device will cease functioning.

When drilling operations are initiated, the rotation of the drill stem will cause the centrifugal switch 22 to open, thus shutting off the supply of power to the inclinometer and preventing its operation. The commencing of rotation will also insure that the pin 39 of cycle timer traveling head 38 will slip from engagement with the tab 48 permitting the inertial switch 28 to close and remain closed. Now, whenever rotation of the drill stem is interrupted, the centrifugal switch 22 will close, energizing the timing motor 32 and causing the commutator brush or arm 41 to be driven intermittently through the intermittent drive 33 and brought successively into engagement with the various contacts 42. The head 38 will also be driven intermittently upwardly. Thus, dependent upon which of the angle-sensing switches are closed and which of the contacts 42 are thus connected to the positive lead 82, a series of pulses will be supplied to the armature coil 86 of the transmitter relay causing the relay to close intermittently and thus energize the coil 89 of the transmitter intermittently for sending a series of acoustic pulses upwardly through the drill stem to the receiver 90. The number of the pulses minus one will indicate, of course, how many of the switches 35 are closed and thus the angularity of the drill stem at the drill bit. These series of pulses will be repeated throughout one complete cycle so long as the drill stem remains stationary, and thus, a number of the groups of pulses will be trans- Initted, permitting verification and certainty of the number of pulses being received. In this manner, the first contact members of the angle-sensing switches are afforded .an opportunity to come to a complete rest and assume accurately the actual angularity of the drill stem. At any time, however, that rotation of the drill stem is again brought into being, the centrifugal switch 22 will open, stopping the timing motor and stopping the transmitting of the series of pulses. The next time the drill stem is stopped, the signalling will be reinstated until such time as the cycle timer 26 reaches the upper end of its stroke, causing the pin 39 to close the reversing switch 25, actuating the coil 80 of the reversing relay and reversing the rotation of the timing motor. Now, the head 38 will be driven downwardly, the holding switch 85 preventing deenergization of the reversing relay 24 when the reversing switch 25 opens, the downward movement continuing steadily or intermittently in accordance with rotation of the drill stem l r til the pin opens the inertial switch 28 and stops the motor 32. During this period, the commutator brush 41 will be driven in the opposite direction from that of its previous travel, but this is immaterial since the same number of pulses will be transmitted and it will thus be known how many of the angle-sensing switches are closed. It is to be noted that this is one feature of the intermittent drive in that it functions positively and effectively regardless of the direction in which it is being driven or driving.

The inertial switch 28 being opened by engagement of the pin 39 with the tab 48, the switch will be closed again whenever rotation of the drill stem again begins, the inertia of the weight 27 causing it to stand still momentarily, removing the finger 39 from alinement with the tab 48 and permitting the switch 28 to close and remain closed so that the inclinometer is in condition for beginning another cycle whenever the centrifugal switch 22 agains closes.

The entire signalling cycle may be of any desired length, it being perferable that the cycle be restricted to several minutes duration to minimize drain upon the batteries 21. Thus, the time required for the complete upward stroke and downward return stroke of the head 38 may be of the order of three minutes or so, making provision for the eventuality or likelihood that at times the drill stem may not be rotating for periods of thirty minutes or an hour or two. Under these conditions, the inclinometer runs through one complete cycle and then stops, its operation not commencing again until the drill stern has been placed in rotation and then subsequently stopped.

The angle-sensing switches being very sensitive and substantially friction-free, extremely accurate determinations of the angularity of the drill stem are provided, and clearly, the malfunctioning of any one of the angle-sensing switches does not preclude the proper functioning of the remaining switches. The battery or batteries may be checked and replaced as needed whenever the drill stem is pulled from the well bore to replace or check the drill bit or whenever the drill stem is pulled for any other reason.

It is noted that the ray of angle-sensing switches 35 may be employed as a separate assembly without the motor, intermittent drive, commutator, timer and the remaining elements of the complete unit, and lowered into a well bore upon a suitable multiple-conductor electric cable for independent surveying operations, this sub-assembly being used separately as a cable tool from the ground surface with angularity readings being noted at the ground surface as electrical signals from those of the angle-sensing switches 35 which may be closed.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. An inclinometer for measuring the angularity of a well bore including a housing, a plurality of separate angle-sensing means in the housing each being responsive to a greater degree of angularly than each preceding angle-sensing means to generate a signal, means for transmitting to the ground surface a signal from each of the angle-sensing means that is activated, and an inertial switch for terminating the angle measuring by opening, the inertial switch being responsive to the commencing of rotation of the inclinometer to reclose.

2. An inclinometer as set forth in claim 1 and a centrifugal switch for de-energizing the inclinometer when the latter is rotating.

3. An inclinometer for measuring the angularity of a well bore including a housing, a plurality of separate angle-sensing switches in the housing each being responsive to a greater degree of angularity than each preceding angle-sensing switch to close a circuit, a timing motor,

a multiple contact commutator having contacts connected to the angle-sensing switch circuits, an intermittent drive means connecting the timing motor to the commutator for driving the commutator intermittently and momentarily closing its contacts in sequence, a signal generator connected to and energized by the commutator for transmitting to the ground surface a signal from each of the time-sensing switches that is closed, and an inertial switch for terminating the angle measuring by opening, the inertial switch being responsive to the commencing of rotation of the inclinometer to reclose.

4. An inclinometer as set forth in claim 3 and a centrifugal switch for de-energizing the inclinometer when the latter is rotating, the centrifugal switch and the inertial switch being in series and the timing motor being energized therethrough.

5. An inclinometer as set forth in claim 3 and a reversing switch for the timing motor, a cycle timer driven by the timing motor, and an actuating pin carried by the cycle timer having an operating stroke between a first position in which it closes the reversing switch and a second position in which it opens the inertial switch.

6. An inclinometer as set forth in claim 3 and a reversing switch for the timing motor, a cycle timer between the reversing switch and the inertial switch including a travelling head, an elongate screw in screwthreaded engagement with the travelling head, and a driving connection between the screw and the timing motor for driving the travelling head in one direction to close the reversing switch and upon reversal of the timing motor for driving the travelling head in the opposite direction to open the inertial switch.

7. An inclinometer as set forth in claim 3 wherein the intermittent drive means includes a supporting member having first and second transverse support members, a driving shaft carried by the first support member and connected to the timing motor, a driving pin eccentric on the driving shaft and projecting toward the second support member, a fixed pin on the first support member eccentric of the driving shaft and projecting toward the second support member, a driven shaft carried by the second support member and connected to the commutator a mounting member carried by the driven shaft and positioned between the first and second support members, a plurality of spaced driven pins on the mounting member projecting toward the first support members and arranged in a circle concentric of the driven shaft, and a link pivotably mounted on the driving pin and having an elongate slot receiving the fixed pin, the outer end of the link being longitudinally notched for engaging successively the driven pins to evolve the driven shaft intermittently.

8. An inclinometer as set forth in claim 3 wherein the intermittent drive means includes a supporting member having first and second transverse support members, a driving shaft carried by the first support member and connected to the timing motor, a driving pin eccentric on the driving shaft and projecting toward the second support member, a fixed pin on the first support member eccentric of the driving shaft and projecting toward the second support member, a driven shaft carried by the second support member and connected to the commutator, a mounting member carried by the driven shaft and positioned between the first and second support members, a plurality of spaced driven pins on the mounting member projecting toward the first support member and arranged in a circle concentric of the driven shaft, and a link pivotably mounted on the driving pin and having an elongate slot receiving the fixed pin, the outer end of the link being longitudinally notched for engaging successively the driven pins to evolve the driven shaft intermittently, the

outer end of the notch in the outer divergent.

9. An inclinometer as set forth in claim 3 wherein the intermittent drive means includes a supporting member having first and second transverse support members, a driving shaft carried by the first support member and con-- nected to the timing motor, a driving pin eccentric on the driving shaft and projecting toward the second support member, a fixed pin on the first support member eccentric of the driving shaft and projecting toward the second support member, a driven shaft carried by the second support member and connected to the commutator a mounting member carried by the driven shaft and positioned between the first and second support members, a plurality of spaced driven pins on the mounting member projecting toward the first support member and arranged in a circle concentric of the driven shaft, and a link pivotally mounted on the driving pin and having an elongate slot receiving the fixed pin, the outer end of the link being longitudinally notched for engaging successively the driven pins to evolve the driven shaft intermittently, the driving pin, the fixed pin and the driven pins extending through a common transverse plane.

10. An inclinometer for measuring the angularity of a well bore including a plurality of separate angle-sensing switches in the housing each being responsive to a greater degree of angularity than each preceding anglesensing switch to generate a signal, each angle-sensing switch including a supporting member having an upper support member and a lower support member, a support pin adjustably mounted in the lower support member for vertical adjustment therein and projecting upwardly toward the upper support member, a first contact member the first contact member being frusto-conical and hollow and being pivotably supported on the upper end of the support pin, a stop pin adjustably mounted on the upper support member for vertical adjustment therein and projecting downwardly toward the first contact member, the lower end of the stop pin being spaced at short distance from the upper end of the first contact member, a second contact member around the first contact member and spaced therefrom when the angle-measuring switch is vertical, the two contact members being adapted to engage when the angle-measuring switch is inclined to a predetermined angle, means electrically insulating the first and second contact members from one another, and means for transmitting to the ground surface a signal from each of the angle-sensing switches that is closed.

11. On inclinometer as set forth in claim 10 wherein the lower exterior of the first contact member is bevelled inwardly and downwardly.

12. An inclinometer as set forth in claim 10 wherein the first contact member is pivotably supported upon the support pin through a spherical surface.

13. An inclinometer as set forth in claim 12 wherein the first contact member is of very large mass in proportion to the area of the spherical surface through which it is supported.

end of thelink being References Cited by the Examiner UNITED STATES PATENTS 3,004,613 10/1961 Murphey 33-205.5

LEONARD FORMAN, Primary Examiner.

W. K. QUARLES, W. D. MARTIN,

' Assistant Examiners.