US2656027A - Position control device - Google Patents

Description

Oct. 20, 1953 R. R. cRooKsToN 2,656,027

POSITION CONTROL DEVICE Filed May 15, 1950 2 Sheets-Sheet 1 BLEEDER VALVE ASSEMBLY "All mvntb'a Robert R- Crook stqn,

ATTORNEY.

GEAR BOX Oct. 20, 1953 R. R. CROOKSTON 2,655,027

POSITION CONTROL DEVICE Filed May 15, 1950 2 Sheets-Sheet 2 "llllllll Illllll lilllllllIIlFllllll -FIG.8.

VALVE STEAM BOILER INVENTOR.

Robert R. Crooksfon,

"msm

ATTORNEY.

Patented Oct. 20, 1953 [TED s'm'r ES PAT Emir OFFICE POSITION EONTROL DEVICE Robert R. firookstorr, Houston; -'1"ex'., assignor; by

mesne assignments, to Standard Bil Development (Company, Elizabeth, N; J a corporation of'Delamare Application May 1 3", 1950, SeriaIlNo. 161,883"

43 Claims. I

The present invention relates to a signalling device and, more: particularly, relates toa s-ig-- nalling' device adapted for use in connection t hoistingfdfivice.

Movement of loads from one point: to another in a relatively straight line is often accomplished by means of a wire line spooled on a power driven drum. In such devices the load may be moved in; one direction by' permitting the linetobe paid ojfij the drum and may be moved in a direction opposite from the aforesaid direction by means of spoofing the line onto the drum. Such an arrangement is used, for example, inelevators, hoists employed in the building trade, and in rotary drilling rigs employed in the drilling or boreholes into subsurface formations. In the operation of such devices it is often necessary that the paying off and spooling" on of the line offaofj and onto the drum becontrolled sothat theload being lifted" may be stopped atany desired point in its travel. For example, in the case of a personnel elevator or of ahoi'st used in the building trade, it is necessary that the hoistor elevator be provided withdevices which will enable the stopping of th elevator-or hoist ata particular point in, their verticaltravel, suchasat' a: floor level. It is, of course; also necessary that hoists orelevators be equipped with rogu lators which will prevent the elevator or hoist fromstriking the sheave over which the'cable supporting the elevator or hoist in its shaft passes. Regulators must also be provided for preventing elevators and hoists from colliding with the fl'oorat the bottom of theshaft. With out such regulators, elevators andhoi'sts would; of course, be extremelydangerousto personnel usingsa-me.

A similar condition exists in drilling rigs-em;- ployed for thedrilling" of boreholes into subsur-- face formations. on a drum is used for lowering and raising loads within the derrick. The cable extends from the" draw works drum over the top of suitable sheaves rotatably mounted in the crown block of the den-- rickand through-the shea-vesot atravelllng-blbck, one end of said cablebeing attached to-some fixed point, usually the derrick itself; The-travelling block is raised within the derrick by means of spoofing the cable onto the drum and is lowered within the derrick b y means or: paying the. cable.

ofi the drum. When the travelling ismowlng. upwardly within the: derrick and; when, it; is desired to. stop 5 this upward movement, is the operator throttles and shuts off the draw; works engjneand mgy also apply a-braking. force 11 the drum for the purpose of quickly stopping its Insuch rigs a cable spool'ed rotation. When the travelling block is moving downward-1y" within the derrick and it is desired tostop such downward movement; the" operator" merely applies a braking force of suificient mag nitude tothe drum to stop its rotation and, ac cordingly, further descent of'the travelling block ceases.

heretofore; drilling rigs have been equipped with devices intended to stop the movement of the travelling blbck' at a fixed point within the derrick without intervention of the driller; Siiclr devices are primarily intended to prevent the travelling block from striking thecrown block a a result of the failure of'the operator tostop the draw worksdrum at the proper time; Itwill be appreciated, of course; that a-device of this type is highly desirable from the standpoint of the safety of the operating" crew and also from the standpoint of preventing unnecessary (fie-- struetion of equipment due to errors injudgment" of the draw works operat'or. The ability of the opera t'or" to stop the upward travel or the travel ling block before itstrikes the crown block d"e*-- pends,- of course, upon his abilityto: see theerown block upon his estimate asto the rateof ascent or the travellingblock. The elements seriously inter-tore with. both vision and his estimate:- Rain; snowy oreverr the sum may seriously impairthe vision oftheoperator and a fie'ct: his'estimate of the closeness or approach-- ofitltre-trawelling blocks to the crown block, there-- by allowing hiimto make: anerror in: judgment which will permit the travelling Mock to strike the crown block.

It is. essential that'the travelling block: be stopped in its; vertical ascent before it strikes the: crown bloom it is often desirableto sto the travellmgebloolc at a particular point either its vertical upward travel or its vertical down ward travelt Forexample, modern drilling equipment, it may be desirable-that thetravelling bloclr bestopped art-a fixed distance from thefioor" of thedernibk every time thetravelling bloclt is lowwediwithiiithederrick:

Anobject orthe present inventi'bn'is' to pro vide a device arranged for providing a signal or a; series or signalsind-ibatitwofthe position of a load movable between two extreme limits travel,--the-loaii being associated w-ith 'as-lihe and the position" ofsaid-loan rein-e alterabfe tyretation of the drum upon which the line isspooled; A' further obj'ectisto provi'de a; devi'oe whibh will; supply a signal capable of being e pl f ii -td prevent a load attacheditb a wire .Iine spooledt upon a drum from being movedlty the operator."

beyond a certain fixed point. A further object is to provide a device which is operated off the draw Works drum itself.

Briefly, the device of my invention may be described as a device arranged to provide a signal or a series of signals indicative of the position of a member associated with a line between a first limit of travel and a second limit of travel along a straight path, the position of said member being alterable by rotation of the drum upon which the line is spooled. Since it is desired to employ the rotative motion of the drum for providing the aforementioned signal, a conventional speed reducing mechanism is operatively connected to the drum, the speed reduction being such that a shaft attached to the output side of the speed reducing mechanism rotates no more than one revolution for drum rotation sufiicient to move the aforementioned member from its first limit of travel to its second limit of travel. This amount of speed reduction is necessary in order to permit control over the entire range through which the said member may be moved. In the case of a drilling rig, the travelling block may be moved from the floor, which may be regarded as one limit of travel, to the crown block, which may be regarded as the other limit of travel. A cam actuating arm is mounted on the aforementioned shaft for rotation therewith. Preferably, the cam actuating arm is adjustable with respect to the shaft so that minor adjustments may be made from time to time to correct for such things as wear of the cable or line. A signalling means, such as a bleeder valve, is spaced from the aforementioned shaft and is arranged to be actuated by a cam which is, in turn, actuated by the cam actuating arm. The signalling means and its actuating cam are arranged to be moved radially about the axis of the aforementioned shaft so that it may be so placed as to provide a signal at any selected point in the movement of the aforementioned member between its two limits of travel. It will be understood, of course, that a plurality of signalling means may be employed in conjunction with appropriate cams so that a plurality of signals'may be provided. The signal or signals may,

of course, be employed in any desired manner.

and may be used, for example, for ringing a bell, for activating a light bulb, or for throttling and/or stopping the draw works engine and/or for applying the brake to the drum.

A detailed description of the .device of my invention will hereinafter be set out. in conjunction; with the, drawing in which like numerals designate likeparts throughout and in which:

Fig l, is an isometric view. of the device of my invention mounted onthe draw works of adrilling rig;

. Fig.) is a detailed view, partly in' crossesec ti'on,of the device shown inFig. 1; I I V .Fi g. is a ;de ta iled view, partly, incross-secr. tion, ofaportion'of the device shown in Fig.2; Fig. 4 is a detailed view, partly in cross-sec.- tion, of another portion, of, the device shown in Fig.2 1

5 is a detailed view of aportion of, the show ng ofFig..3; r Q

Fig. dis a detailed view of that portion ofFig, 21fdesignated diagrammatically asaspeed reduceria.

in Fig". '2; and v Fig. 8 'isan illustration of one mode in which Fig. 7 a modification o' fthe device illustrated the device 'of the present invention may be used CPI . gears.

in conjunction with the travelling block of a drilling rig.

Referring to the drawing, and particularly to Figs. 1 to 6, inclusive, the numeral I0 designates a gear which is mounted on draw work drum shaft I I for rotation therewith. The draw works drum I2 is mounted on shaft II, shaft II and drum I2 being supported by draw works guard I3. A bracket I4 is affixed to draw works guard I3 and supports shaft I5 for rotation about its longitudinal axis, the longitudinal axis of shaft I5 being substantially parallel to the longitudinal axis of draw works shaft II. Gear I1 is mechanically affixed to shaft I5 for rotation therewith. Continuous chain I8 meshes with the teeth of gears I0 and I1 mechanically connecting said The outer end I9 of shaft I5 terminates within gear box 20 and mounted on this outer end for rotation therewith is bevel gear 2 I. Shaft 22 is supported by the Walls of gear box 20 and is adapted to rotate about its longitudinal axis. The inner end 23 terminates Within gear box 20 and the outer end 24 terminates externally of gear box 20. Mounted on the inner end 23 of shaft 22 for rotation therewith is bevel gear 25, the teeth of which mesh with the teeth of bevel gear 2 I.

Meter housing 26 may be affixed to any suitable support and is shown in Fig. 1 as being affixed to a portion of the draw works guard I3. Housing 26 supports shaft 21 for rotation about its longitudinal axis, the outer end 23 of shaft 21 extending externally of housing 26 through the rear wall 29 thereof. Shaft 30 is also supported by housing 25-, the outer end 3I of said shaft also extending externally of housing 25 through rear wall 29. Shaft 32 is supported by housing 26, one end 33 of said shaft extending externally of housing 26. Shafts 21, 3B, and 32 are so arranged that their longitudinal axes are substantially parallel. Shaft 31! is supported by housing 26 for rotation about its longitudinal axis and ex.

tends through the lower wall 35 of said housing. The longitudinal axis of shaft 34 is substantially perpendicular to the longitudinal axis of said shaft, the teeth of gear 38 meshing with the teeth of gear 40. Gears 39 and 49 are enclosed by means of closure cover I6 removably secured tohousing 25 by means of bolts I6. Gears 39 and 40 are transposition gears of a. ratio, equal .to the square root of the number of lines for which the device might work. Gear lI is mounted within housing '25 on shaft 30 for rotation therewith. Gear 32 is mountedwithin housing 26 on shaft 32 for rotation therewith. Shaft 22 and shaft 34 are mechanically connected by means of flexible shaft 66.

Numerals IUIa and I682) form part of the speed reducing mechanism indicated diagrammatically in Fig. 2. This speed reducing mechanism is of conventional design and may suitably be constructed in the manner shown in detail in Fig. 6. In Fig; 6 a plurality of gears numbered IflI to I08, inclusive, are shown. Gears IIII, I03, I05, and Bill are mounted on shaft 32 for free rotation ofthe travelling blocks within the derrick. For example, it may be desirable to employ a second bleeder valve assembly similar in construction to bleeder valve assembly A so that travelling block I23 may be stopped automatically a predetermined distance from the derrick floor I2I as the travelling block moves downwardly within the derrick. This is accomplished by merely setting the second bleeder valve assembly at the proper point on the outer periphery of ring gear 49.

One specific mode of using the device of the present invention to control the vertical height of the travelling block within the derrick is illustrated diagrammatically in Fig. 8. In this figure a conventional derrick I mounted on a suitable platform I2I is shown. Mounted in the top of the derrick I20 is crown block I22 and suspended from crown block I22 is a travelling block I23 carrying a string of pipe I24, travelling block I 23 being suspended from crown block I22 by means of. wire line I25. Wire line I25 is Wrapped on draw works drum I2 equipped with brake shoe I26. Draw works drum I2 is adapted to be rotated in one direction for raising travelling block I23 by means of engine I2! and is adapted to be rotated in the opposite direction for lowering travelling block I23. Brake shoe I26 is adapted to be engaged with and disengaged from brake drum I2 by means of brake cylinder I28. Engine I21 is powered by means of steam furnished from steam boiler I29 through conduit I30. Brake cylinder I27 causes brake shoe 26 to be engaged with draw works drum I2 when compressed air is supplied thereto through line I3I, the compressed air being furnished by means of air com r pressor I32. A spring pressed valve I33 is positioned in line i3I. Valve I33 is so designed that spring I34 will open said valve to permit air to flow through conduit I3I to brake cylinder I28 when air is exhausted from the lower end I35 thereof. The supply of steam to engine I21 from steam boiler I29 is controlled by throttling valve I36 andclosure valve I3'I positioned in line I30. Throttling valve I 36 is so designed that spring I38 tends to close said valve to reduce the amount of steam flowing through line I38 when air is bled from portion I39 of said valve. Valve I3! is so designed that spring I69 tends toclose said valve to cut off the supply of steam through conduit I when air is allowed to bleed from portion I! of said valve. Portion I of valve I33 is fluidly connected with conduit 55 by means of line I42, branch line Hi3, and branch line M4. Portion I 4| of closure valve 231 is fluidly connected with conduit 65 by means of line I42 and branch line I 45; Throttling valve I36 is fluidly connected with conduit 65 by means of line I62 and branch line I46. An orifice I4! is positioned in line I45 while orifice I48 is positioned in line I46 and orifice I49 is positioned in line I42 downstream of the point at which lines I45 and I46 join line I42. Compressed air is supplied from an outside source, not shown, to conduit 65 through line I50 which may be controlled by valve I5I.

Orifices I47, I48, and I49 are of such size that air may bleed from throttling valve I38 before air is bled from closure valve I31 and that air is bled from both throttling valve I36 and closure valve I31 before air is bled from valve I33 in line I 3I. With this arrangement the actuation of bleeder valve 64 permits air to bleed first from throttling valve I 36, thereby reducing the amount of steam supplied to engine" I27 from steam boiler .29 through conduit I33. Next air bleeds from closure valve I31, thereby cutting off the supply of steam from steam boiler I29 to engine I21. Air next bleeds from valve I33, permitting com pressed air to flow through conduit I3I into brake cylinder I28, thereby actuating brake cylinder I28 to cause brake shoe I26 to engage with draw works drum I2 to completely stop the rotation of said drum.

It will be apparent from the foregoing description with respect to Fig. 8 that actuation of bleeder valve 64 initiates the aforementioned sequence of events. The particular point in the vertical travel of travelling block I 23 at which bleeder valve 64 is actuated will depend upon the position at which bleeder valve assembly A is set on the outer periphery of ring gear 49. It may be set, for example, to prevent the travelling block I23 from striking crown block I22.

It will be apparent that various modifications may be made in the device hereinbefore described without departing from the scope of the present invention. For example, Fig. 7 illustrates a means for transmitting the rotary motion of draw works drum shaft I I to gear 39 which differs from the means shown in Fig. 2. Referring to Fig. 7, a shaft I Ia is mechanically connected with draw works drum shaft II so that shaft IIa rotates in cooperation with draw works drum shaft 3 I. A gear I Ib is affixed to shaft Ila for rotation therewith, the teeth of gear IIb meshing with the teeth of gear 39.

Having fully described and illustrated the device of the present invention, what I wish to claim as new and useful and to secure by Letters Patent is:

l. A device arranged to control the position of a load attached to one end of a line, the other end of said line being spooled on a rotatable drum, said load being movable by said drum and said line from a first limit of travel to a second limit of travel, comprising a shaft mounted for rotation about its longitudinal axis; a speed reducing mechanism connecting said drum and said shaft for transmitting the rotary motion of said drum to said shaft, said speed reducing mechanism being arranged to rotate said shaft no more than one revolution for rotary drum motion sufficient to move said load from its first limit of travel to its second limit of travel; a cam actuating arm mounted on said shaft for rotation therewith; an assembly radially spaced from said shaft, said assembly carrying a bleeder valve having an inlet, a conduit containing fluid under pressure fluidly connected with said inlet, and an exhaust port for bleeding fluid from said conduit when said bleeder valve is actuated, said assembly carrying a r0- tatable camshaft having a first cam mounted on said cam shaft for rotation therewith in a first direction and for rotation thereon in a second direction and a second cam aifixed thereto, said first cam being disposed in the path of said cam actuating arm and said second cam being arranged to actuate said bleeder valve when said first cam is rotated in said first direction by said cam actuating arm; and a valve member in said conduit arranged to stop the rotation of said drum when fluid is bled'from said conduit by said bleeder valve.-

2. A device arranged to control the position of a travelling block suspended from a line in a drillingderrick for vertical movement in the derrick between the floor and crown thereof, the vertical position of said travelling block being alterable by rotation of the drum upon which said line is spooled, said drum being rotatable by anengine for raising said travelling block, comprising, in combination, a shaft mounted for rotation about its longitudinal axis; a speed reducing mechanism connecting said drum and said shaft for transmitting the rotary motion of said drum to said shaft, said speed reducing mechanism being arranged to rotate said shaft no more than one revolution for rotary drum motion sufficient to move the travelling block from the floor to the crown of the derrick; a cam actuating arm mounted on said shaft for rotation therewith; an assembly radially spaced from said shaft, said assembly carrying a bleeder valve having an inlet, a

conduit containing fluid under pressure fluidly connected with said inlet, and an exhaust port for bleeding fluid from said conduit when said bleeder valve is actuated, said assembly carrying a rotatable cam shaft having a first cam mounted on said cam shaft for rotation therewith in a first direction and for rotation thereon in a second direction and a second cam aflixed thereto, said first cam being disposed in the path of said cam actuating arm and said second cam being arranged to actuate said bleeder valve when said first cam is rotated in said first direction by said cam actuating arm; a first valve member in fluid communication with said conduit arranged to reduce the supply of energy to said engine when fluid is bled from said conduit by said bleeder valve; a second valve member in fluid communication with said conduit arranged to cut off the supply of energy to said engine when said fluid is bled from said conduit by said bleeder valve, said second valve member being arranged to be actuated subsequent to the actuation of said first valve member; a third valve member in fluid communication with said conduit arranged to stop rotation of said drum when fluid is bled from said conduit by said bleeder valve, said third valve member being arranged to be actuated subsequent to the actuation of said second valve member.

3. A device in accordance with claim 1 in which an indicating needle is mounted on said actuating arm and a face is mounted adjacent thereto.

4. A device in accordance with claim 2 in which an indicating needle is mounted on said cam actuating arm and a face is mounted adjacent thereto.

ROBERT R. CROOKSTON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 494,519 Bolthofi' Mar. 28, 1893 697,772 Allison Apr. 15, 1902 962,762 Iversen June 28, 1910 1,002,820 Brown Sept. 12, 1911 1,209,231 Tebbs Dec. 19, 1916 1,213,956 Royer Jan. 30, 1917

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