Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3101828 A
Publication typeGrant
Publication dateAug 27, 1963
Filing dateMay 9, 1960
Priority dateMay 9, 1960
Publication numberUS 3101828 A, US 3101828A, US-A-3101828, US3101828 A, US3101828A
InventorsHart Wilson John
Original AssigneeHart Wilson John
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Safety stop for the traveling block of drilling rigs
US 3101828 A
Abstract  available in
Images(2)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Aug. 27, 1963 SAFETY STOP Filed May 9, 1960 J. H. WILSON 3,101,828

FOR TRAVELING BLOCK OF DRILLING RIGS 2 Sheets-Sheet 1 b- \II In L J r min L I I I H15 AGENT 1963 J. H. WILSON 3,101,828

SAFETY STOP FOR TRAVELING BLOCK OF DRILLING RIGS Filed May 9, 19.60

2 Sheets-Sheet 2 IZfig. 5

JJH/V M914 7 l V/ 501V INVENTOR.

H15 HEENT United States Patent 3,101,828 SAFETY STOP FOR THE TRAVELING BLOCK 0F DRILLING RIGS John Hart Wilson, Wilson Manufacturing Co., R0. Box 1031, Wichita Falls, Tex. Filed May 9, 1960, Ser. No. 27,655 Claims. (Cl. 192-139) This invention relates to an automatic stop for a hoist, and more particularly to a traveling block safety stop for drilling rigs, which safety stop will limit the upward movement and the downward movement of the traveling block of a drilling rig.

Traveling block stops have been proposed heretofore, for limiting the upward movement of traveling blocks, such as disclosed in my Patent No. 2,5 64,457, issued Aug. 14, 1951, Safety Device for Drilling Rigs, however traveling block stops of this character necessitated the use of an element in the derrick for actual physical engagement with the traveling block to actuate a member which would stop the traveling block on the upward movement only thereof. This traveling block stop would not stop the downward movement of the traveling block, therefore the driller had always to be on the alert to see that the downward movement of the traveling block did not endanger workmen by the descent thereof below a predeterboth the maximum upward and the downward movement of the traveling block can be accurately controlled, and the stops of the device may be individually and readily adjusted either at the uppermost point of travel or the lowermost point of travel, without affecting the stopping of the traveling block at any intermediate point, either on the upward or downward movement thereof.

An object of this invention is to provide a stop mechanism for the hoisting drum of a drilling rig which will stop the hoisting drum either during the winding of the cable or the paying out of the cable, at a predetermined point, thereby enabling the movement of the traveling block, with which the cable is strung, to be accurately controlled within predetermined limits.

Another object of this invention is to provide a stop for the traveling block of a drilling rig, which is connected in direct, geared relation to the hoist drum of the drilling rig, and which may be readily adjusted without having to adjust stops within the length of the derrick.

Still another object of the invention is to provide a stop for a traveling block of a drilling rig, which is simple in construction, which is compact, and which may be readily installed on any drilling rig.

A further object of the invention is to provide a traveling block safety stop which may be selectively by-passed by the driller to enable the traveling block to move to a higher or a lower elevation, without moving the preset automatic stops.

With these objects in mind and others which will become manifest as the description proceeds, reference is to be had to the accompanying drawings in which like reference characters designate like parts in the several views thereof, in which:

FIG. 1 is an elev-ational view of a rotary drilling rig, including the derrick thereof showing the traveling block therein, with parts of the derrick being broken away, and with the traveling block being shown in full outline, in one extreme position, the opposite extreme position thereof being shown in dashed outline, the traveling block safety stop mechanism being shown attached to the drawworks of the drilling rig;

FIG. 2 is an elevational view of the drawworks of a conventional rotary drilling rig, which utilizes air actuated clutches and an air actuated braking system on which is shown diagrammatically the traveling block control system, which is connected thereto;

FIG. 3 is an enlargedcross-sectional, elevationalview showing one of thecontrol valves within the control system;

FIG. 4 is an enlarged elevational view of a four-way control valve which enables the actuation of the air clutches and the air brake system, with portions of the valve being broken away and portions being shown in section to bring out the details of construction;

FIG. 5 is an enlarged elevational view of the traveling block safety stop mechanism, with parts broken away and with parts shortened, and showing the manner of conmeeting the mechanism to the rotating shaft, such as a drum shaft;

FIG. 6 is a top plan view of the operating mechanism of the stop mechanism, with a portion of the cable being broken away;

FIG. 7 is an elevational view of the stop mechanism as shown in FIGS. 5 and 6; and

FIG. 8 is a fragmentary elevational view of one of the cams of the stop mechanism and showing a portion of the cam disc to which the cams are secured.

With more detailed reference to the drawing, the numeral 1 designates generally a drilling rig derrick with the drilling rig hoist mechanism or drawworks designated generally at 2, which drawworks is positioned on the derrick floor. A swivel 4- is suspended by a traveling block 6, which traveling block is suspended by cable 8, which cable passes off drum Ill and over crown block sheaves 1 2 to support the traveling block 6 for upward or downward movement within derrick 1, as is well understood in the art of well drilling.

The traveling block satiety stop, which is designated generally at 14, is attached, through flexible shaft 16 and angle drive unit 18, to a drum shaft 20, which drum shaft is rotatable with the drum 10. A shaft 22 extends outward from angle drive unit 18 and is connected with drum shaft 20 by means of a tongue member 24 which interconnects with a complementary slotted member 26 of the drum shaft 26. It is preferable that the gearing on the right angle drive unit 18 be of a character to obtain a reduction of speed of the flexible shaft 16. The flexible shaft 16 drives into a speed reducer gearing within housing 15 so as to revolve shaft 28 at a low speed ratio with respect tothe speed of the drum shaft 20.

A cam disc 30 is fixedly secured to shaft 28 of speed reducer gearing so as to rotate in geared relation with respect to drum shaft 20. The peripheral edge of the cam disc 30 is dove-tailed, as indicated at 32, and as best seen in FIGS. 5 and 8, to receive complementary, dovetailed, arcuate earns 34, 34b, 35 and 35b thereon. The arcuate cams 34 and 35- are relatively long and are disjposed on opposite sides of dove-tail periphery 32 in cam disc 30. The cams 34 and 35 are so positioned that the adjacent end portions will be in side-by-side, overlapping relation so as to present a uniform diameter cam follower roller engaging surface throughout the combined arcuate length of cams 34 and 35. Shorter cams 34b and 35b are disposed on opposite sides of dove-tailed portion 32 of cam disc 30, with the outer end of cam 34b being in transversely aligned relation with the outer end of cam 34 and the outer end of cam 35b being in transversely aligned relation to the outer end of cam 35, so that the cam follower roller will simultaneously engage said adjacent transversely aligned ends of the respective cams.

The arrangement of the cams in this manner allows a wide range of adjustments of the cams to be had on cam disc 30, while a uniform peripheral arcuate cam follower roller surface for cam follower roller 42 to roll upon is maintained, to prevent the cam follower roller 42 from overrunning the cam to cause the air valve 48 to be opened.

The cams 34, 34b, 35 and 35b are held on the disc 30 by means of bolts 36 which bindingly engage the edges of the cam with the periphery of the cam disc 30.

An arm 38, which forms a first valve actuator, is pivotally mounted on a pin 40, which pin is positioned on the upper side of housing 15. One end of the arm 38 has a cam follower roller 42 journaled thereon, which roller is in aligned relation with cams 34 and 35. The earns 34, 34b, 35, and 35b each have the roller engaging ends thereof beveled at approximately forty-five degrees, as indicated at 34a and 35a respectively, to enable the roller 42 to roll up on the respective cams, as will be brought out more in detail hereinafter.

{The opposite end of the arm 38 has a set screw 44 threadably engaged therein, which set screw is adapted to engage a slidable plunger 46 in a three-way air valve 48, which valve 48 is mounted on an outstanding bracket on gear housing 15, so as to direct air from a supply pipe 50 into a pipe 52 which leads to and through a three-way control valve 54 to a diaphragm chamber 60, which diaphragm chamber forms a second valve actuator to actuate a four-way air valve 62. The air valve generally designated at 62 is of the slidable plunger type, as will best be seen in FIG. 4, which valves are sold under various trade names, one of which is Valvair. The valve 62, when in one position as shown in FIG. 4, will direct air from an air supply line 64 through the valve 62 and out through conduit 66 and through two-way check valve 68 to direct the air into a conduit 70 leading to and through a quick release valve 72 to a pneumatic cylinder 74 to actuate a brake mechanism designated generally at 76, such as shown in my Patent No. 2,928,505, Brake System for Hoisting Drums, issued March 15, 1960.

Upon movement of valve plunger 65 into position as shown in FIG. 4, the air pressure that was in the particular clutch tube being used, will be vented to atmosphere by opening an axial port in the end of valve 62 opposite the diaphragm chamber 60, to release the pressure in the particular expansible tube of the clutch mechanism which has been last used, whereby a portion of the air will be passed out through pipe 78 and axial opening in valve 62 to drop the pressure in pipe 78, which will enable air to be bled out through quick release valve 86, which will result in the disengagement of the drum clutch, which may at that time be engaged, simultaneously the valve 62 will direct air from supply pipe 64 through conduit 66, double check valve 68, and conduit 70 through quick release valve 72 to the brake air cylinder 74, whereupon the plungers will actuate the brake mechanism 76, which will engage the brakes thereof with :drum 10.

Upon rotation of cam disc 30 in one direction, the cams 34 and 34b will engage roller 42 journaled on arm 38 to depress plunger 46 of valve 48 to open an air passage through valve 48, or the same action will take place if cams 35 and 35b engage the follower roller 42. However, upon reversal of cam disc 30, roller 42 will roll off of the respective cams on which they are engaged, to pivot arm 38 about pivot pin 40 to release plunger 46, which will cause valve 48 to close, which will close the inlet port which leads to air inlet line 50 and open air relief port which will release the pressure from conduit 52 which will cause the spring 63 on valve 62 to then move the valve plunger 65 to open an axial port of the valve 62, which port is adjacent the diaphragm 60 and which port connects conduit 66 therewith, and also lowers the pressure in conduit 70 connected with conduit 66. This will permit the quick release valve 72 to exhaust air from pneumatic cylinder 74, which will release brake mechanism 76.

The same movement of the valve plunger 65 by the 'spring 63, adjacent to the diaphragm chamber which releases the brake mechanism as set out above, also connects the air supply 64 to the conduit 78 which leads to 4 control valve 83 which supplies air to either the high or low speed drum clutches or releases same, and places the rig in normal operating position.

The turning of the drum shaft of the drawworks 2 turns the shaft 22 of the angle drive unit 18 to which flexible shaft 16 is connected. The opposite end of the flexible shaft 16 is connected to a shaft in gear housing 15, which gear housing 15 is so geared as to turn shaft 28, to which cam disc is attached, at a relatively slow speed and in proportion to the revolutions of the drum 10.

A bolt 36 passes through holes in earns 34 and 34b to hold the beveled ends 34a thereof in transversely aligned relation, and a bolt 36 passes through cams and 35b so as to hold the beveled ends 35a thereof in transversely aligned relation.

The earns 34 and 35 overlap transversely so as to present a uniform peripheral diameter so that cam follower roller 42 may either run up on bevel face 34a and be maintained on the face of the cam to close valve 48 until the inertia of the moving drum is arrested, or the cam follower roller 42 may roll up on bevel face 35a onto the face of the cam, when cam disc 30 is rotating in the opposite direction and which roller 42 remains on the face of the cam 34 or 35 to maintain the valve 48 closed until the drum 10 is arrested. By having the cams 34 and 35 overlapping transversely, such arrangement gives an extended =arcuate length of travel of the cams relative to the cam follower roller 42, thereby obviating the possibility of the cam follower roller rolling off at the opposite end of the cam and opening valve 48 which would allow continued movement of the traveling block 6.

As the cam follower roller 42 rolls up onto either cam 34 and 34b or 35 and 35b, the pivoted arm 38 will pivot about pin to actuate valve 48 by depressing plunger 46, which will admit air through air supply conduit and through three-way valve 48 and direct air out through conduit 52 through valve 54 to act upon diaphragm in diaphragm chamber to move the plunger to the position as shown in FIG. 4. When the cam roller 42 moves off cam 34 and 34b or cam 35 and 35b, the plunger 46 of valve 48 will move upward, therefore the air will exhaust through conduit 52 and upward through a passage around plunger 46, in a manner well understood in the art of plunger actuated valves.

Upon release of pressure from conduit 52, spring 63 in valve 62 will move plunger 65 into position to close the port at the end of the valve opposite diaphragm chamber 60 and open a port around the plunger 65 adjacent the diaphragm chamber 60.

The conduit 78 which leads from one of the ports of valve 62 connects to a three-way control valve 80, which has branch conduits 81 and 82 leading therefrom. The conduits 81 and 82 lead through a dual rotary air seal 84 into and through conduits in the shaft of drum 10, in a manner as shown in my Patent No. 2,774,45 3, Pneumatic Clutches. The valve has a lever 83 thereon which actuates the valve members therein to selectively direct air either into conduit 81 or into conduit 82 to direct air to the axially expansible air clutch tubes 85 or 87, respectively. Quick release valves 86 and 88 are mounted within the respective conduits 81 and 82 adjacent the respective air clutch tubes 85 and 87, so upon release of air from conduits 81 and 82, respectively, the quick release valves 86 and 88 will quickly bleed the air from the respective air tubes.

It is preferable to have the gear ratio of cam disc 30 to drum shaft 20 about two hundred to one, so upon the normal turning of the drum, which is from fifty to one hundred twenty-five turns, the traveling block 6 will be moved the desired distance in the derrick 1, depending on the height of the derrick. The earns 34 and 34b and 35 and 35b may be readily adjusted to actuate mechanisms to stop the traveling block at any desired point in the travel thereof, which engagement of the cams with the earn follower roller 42 will initiate an action which will disengage either of the clutches and simultaneously apply the brakes of brake mechanism 76. The earns 34 and 34b and 35 and 35b are beveled on the respective ends thereof, as indicated at 34a and 35a, so that the came follower roller 42 will roll up on the face of the respective cams with a gradual rise, so as to prevent an abrupt stopping of the drum 1d) of the dnaww'orks 2. However, the cams 34 and 35 are made with snfficient arcuate length as to overlap transversely so that the roller 42 will move along the face of the cams, in event the momentum of the drum is sulficient to cause an extended rotation of cam disc 30 ifthe drum is notstopped upon the initial engagement of the respective cam faces 34a or 35a thereon on roller 42, thereby preventing damage to either the traveling block safety stop mechanism or to the drawworks traveling block of the drilling rig.

A further control valve 54 is provided with a pedal 55, which pedal is held upward, as is the plunger connected thereto, by a spring 56, which valve 54 is connected within conduits 52 and 52a, and which conduit 52a connects with diaphragm chamber 60. However, upon depressing pedal 55, conduit 52 is closed, and conduit 52a is opened, so as to bleed the air from the diaphragm chamber 69, which will permit the spring 63 in valve 62 to shift plunger 65 toward the diaphragm chamber 60. With the valve 54 depressed, air will bleed out through the axial port on the lower end of valve 54, whereupon, a manually operated valve 90, in air supply line 92, may be opened, which will cause double check valve 68 to shift to direct air into conduit 70, through quick release valve 72 into air cylinder 74 to actuate the brake mechanism '76 to apply braking action to drum Ill.

If it is desired to have the traveling block -6 travel beyond the position where the traveling block would normally stop at that setting of the cam, the pedal 55 on valve 54 can be depressed by the operator, and this will prevent air from valve 48 reaching the diaphragm valve 62, and therefore the automatic stop will be inoperative. This will permit the driller to raise the block higher than the position for which it is normally set, and will also permit him to lower the block below the position for which it is normally set, simply by depressing pedal 55 on valve 54, and by operating lever 83 of clutch control valve 80.

Having thus fully illustrated and described the invention, what is claimed as new and desired to be secured by Letters Patent is: i

l. A safety stop mechanism for selectively stopping the rotation of a power driven winding drum which is mounted on a shaft, a frame mounting the shaft of said winding drum for rotation in either direction, a fluid actuated clutch mounted on the shaft of said Winding drum, a fluid actuated brake mounted on said frame and being connected in braking relation with said winding drum, said safety stop mechanism comprising a gear reduction unit mounted on said frame, means operatively connecting said gear reduction unit in driven relation to the shaft of said Winding drum, a shaft extending outwardly from a side of said gear reduction unit, a cam disc mounted on saidshaft extending outwardly from said gear reduction unit, a cam of effective, adjustable length of at least degrees of arcuate length operably mounted on said cam disc and being rotatable therewith about the axis of said shaft and in unison therewith, a first valve actuator pivotally mounted on said gear reduction unit, a cam follower mounted on said first valve actuator and being actuated by said cam on said cam disc when said shaft is rotated, at first fluid supply conduit to supply fluid under pressure, a first valve mounted on said gear reduction unit and connected in fluid communication with said first fluid supply conduit, said first valve being operable by said first valve actuator upon movement of said cam, a second valve actuator, said second valve actuator being operable by fluid pressure from said fluid supply conduit, 21 fluid conduit connecting the outlet of said first valve and said second valve actuator in fluid communication, .a second valve, said second valve being connected in actuating relation with said second valve actuator, a second fluid supply conduit con nected to said second valve, branch conduits leading from said second valve, one of said branch conduits being connected with the fluid actuated clutch, the other of said branch conduits being connected with the fluid actuated brake, so the fluid actuated clutch and the fluid actuated brake, respectively will be actuated simultaneously, but

inversely, upon movement of said second valve by said second valve actuator in synchronous relation to the cam actuated first valve to direct fluid from said fluid actuated clutch and to direct fluid under pressure to said fluid actuated brake respectively to stop the rotation of said winding drum.

2. A safety stop mechanism for'selectively stopping the rotation of a power driven winding drum which is mounted on a shaft, a frame mounting the shaft of said Winding drum for rotation in either direction, which winding drum has a fluid actuated clutch mounted on the shaft thereof, a fluid actuated brake mounted on the frame and being connected in braking relation with said winding drum, said safety stop mechanism comprising a gear reduction unit mounted on said frame and being operatively connected in driven relation to the shaft of said winding drum, a shaft extending outwardly from a side of said gear reduction unit, cam mounting means fixedly secured to said shaft which extends outwardly from said gear reduction unit, cam means of an effective, adjustable arcuate length operably mounted on said cam mounting means and being rotatable therewith about the axis of said outwardly extending shaft, a fluid supply conduit to supply fluid under pressure, a first valve mounted on said gear reduction unit and being connected in fluid communication to said fluid supply conduit, a valve actuator arm to form a first valve actuator pivotally mounted on said gear reduction unit, a cam follower roller journaled on said valve actuator arm and being adapted to engage said cam, the opposite end of said valve actuator arm being engageable with said first valve to actuate said first valve, a second valve actuator, which valve actuator is openable by pressure, a fluid conduit connecting the outlet of said first valve and said second valve actuator in fluid communication, a second valve connected in mechanical relation to said second valve actuator, so upon movement of. said first valve actuator, fluid under pressure will be directed through the fluid conduit connecting said first valve and said second valve actuator to actuate said valve, a second fluid supply conduit connected to said second valve, two branch conduits connected to said second valve, one of said branch conduits being connected to the fluid actuated brake, said second valve having the other branch conduit connected to the fluid actuated clutch, said second valve being adapted to direct fluid under pressure selectively toeither the fluid actnated brake or the fluid actuated clutch and to simultaneously release pressure from the other of said mechanisms to actuate the fluid actuated clutch and the fluid actuated brake to selectively control the rotation of the winding drum.

3. A safety stop mechanism as defined in claim 2, wherein said cam mounting means comprises a disc-like element, and wherein said cam means comprises at least two cams which are attachably and adjustably secured, at spaced circumferential intervals, on opposite flat faces of said disc-like element, which cam follower roller element engages with said cams, and wherein the transverse periphery of said cams presents an uninterrupted arcuate track for said cam follower roller throughout the length of said cams when said cams are in a selected adjusted position.

4. A safety stop mechanism as defined in claim 2, wherein said cam mounting means comprises a disc-like element, and wherein said cam means comprises at least two cams which are attachably and adjustably secured, at spaced circumferential intervals, on opposite flat faces of said disc-like element, and wherein the transverse periphery of said cams presents an uninterrupted track, throughout the length of said cams, for said cam follower roller when said cams are in a selected adjusted position, and wherein the composite length of said arcuate cams is adjustable, but said arcuate track contacting said roller Will be maintained a uniform height throughout the travel of said cam follower roller.

5. A safety stop mechanism for a winding drum mounted on a frame, which winding drum has a rotating shaft, said safety stop mechanism comprising a gear reduction mechanism connected in geared relation to said rotating Winding drum shaft, said gear reduction mechanism having an outwardly extending shaft, a member mounted on said outwardly extending shaft and being rotatable therewith, a plurality of independently movable, circumferentially adjustable projections mounted on said rotatable member, a first valve mounted on said gear reduction mechanism, a first fluid supply conduit conneoted to said first valve, a first valve actuator pivotally mounted on said gear reduction mechanism and having an end thereof positioned to engage said first valve when said first valve actuator is in one position, the other end of said first valve actuator having means thereon engageable with said projections on said rotatable member to selectively open said first valve when said rotatable member rotates in either direction to selectively direct fluid through said first valve and through said first fluid supply conduit, said gear reduction mechanism being adapted to rotate said rotatable member in timed rela- 0 tion with :the shaft of said winding drum, a second fluid supply conduit, a second valve, a fluid actuated clutch mounted on the shafit of said winding drum, a fluid actuated brake mounted on the frame in braking relation with said Winding drum, a second valve actuator, said first fluid supply conduit being connected to said second valve actuator, said second valve having said second fluid supply conduit connected to the inlet thereof, branch conduits leading from said second valve, one of said branch conduits being connected in fluid communication with said fluid actuated clutch, the other of said branch conduits being connected with said fluid actuated brake so upon fluid being directed through said first valve to said second valve actuator, fluid will be directed from said fluid actuated clutch to disengage said drum from said dmlm shaft, which fluid will exhaust through said second valve, and fluid will be directed from said second valve to said branch conduit which leads to said fluid actuated brake to engage said fluid actuated brake in braking relation with said winding drum.

References Cited in the file of this patent UNITED STATES PATENTS

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2149044 *Feb 18, 1936Feb 28, 1939Nat Machinery CoControl mechanism for forging machines
US2496040 *Feb 15, 1943Jan 31, 1950Ajax Mfg CoControl valve mechanism for clutches and brakes
US2506842 *Jan 20, 1945May 9, 1950Plant Choate Mfg Co IncHydraulically operated clutch and brake unit for winding reels
US2539545 *Dec 11, 1944Jan 30, 1951American Hoist & Derrick CoClutch and brake mechanism
US2564457 *Jun 25, 1948Aug 14, 1951Hart Wilson JohnSafety device for drilling rigs
US2656027 *May 13, 1950Oct 20, 1953Standard Oil Dev CoPosition control device
US2719618 *Sep 19, 1952Oct 4, 1955Nat Machinery CoFluid pressure control apparatus for metal working machines
US2850132 *Aug 17, 1954Sep 2, 1958Ajax Mfg CoSingle stroke press control
USRE17374 *Oct 9, 1922Jul 16, 1929 And henby h
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3651905 *Jan 13, 1970Mar 28, 1972American Hoist & Derrick CoClutch and brake controls for clamshell hoist
US3684244 *Aug 5, 1970Aug 15, 1972Houck Theodore BDuo-block safety device
US4226311 *Nov 6, 1978Oct 7, 1980Loffland Brothers CompanyRotary drive disc brake for drawworks
US4278217 *Jul 25, 1979Jul 14, 1981Blackwell Roy NFishing reel with automatic variable drag
US4545017 *Mar 22, 1982Oct 1, 1985Continental Emsco CompanyWell drilling apparatus or the like with position monitoring system
US4696377 *Sep 27, 1985Sep 29, 1987Ltv Energy Products CompanyBrake system for drawworks
US4826694 *Apr 4, 1986May 2, 1989Balfour Manufacturing CompanyRuminant feedstuffs, their production and apparatus for use therein
US5167400 *Jun 20, 1990Dec 1, 1992Plateformes Et Structures OceaniquesHas invented certain and useful improvements in control device for lifting winches, in particular for drilling rigs
US5425435 *Dec 15, 1994Jun 20, 1995Gregory Rig Service & Sales, Inc.Brake system for drilling equipment
US7575222 *Jun 16, 2006Aug 18, 2009Hamilton Michael DDrawworks for drilling rigs
WO2004048249A1 *Nov 24, 2003Jun 10, 2004Key Energy Services IncCrown out-floor out device for a well service rig
Classifications
U.S. Classification192/139, 192/144, 254/276, 192/17.00R, 192/17.00A, 192/85.9, 192/48.611
International ClassificationE21B19/00, E21B19/02
Cooperative ClassificationE21B19/02
European ClassificationE21B19/02
Legal Events
DateCodeEventDescription
Aug 11, 1981ASAssignment
Owner name: CONTINENTAL EMSCO COMPANY, 1810 COMMERCE ST., DALL
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:JONES AD LAUGHLIN INDUSTRIES, INC., A DE CORP.;REEL/FRAME:003922/0239
Effective date: 19810623
Owner name: JONES AND LAUGHLIN INDUSTRIES, INC., P.O.BOX 22500
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:WILSON OIL RIG MANUFACTURING COMPANY, 707 NORTH SCOTT ST., WICHITA FALLS, TX 76307 A CORP. OF DE;REEL/FRAME:003922/0232
Effective date: 19810622
Mar 5, 1981ASAssignment
Owner name: WILSON OIL RIG MANUFACTURING COMPANY ,707 NORTH SC
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:WICHITA-WILSON, INC.;REEL/FRAME:003841/0875
Effective date: 19801112