US2959371A

US2959371A - Retrieving mechanism

Info

Publication number: US2959371A
Application number: US603656A
Authority: US
Inventors: James O Melton
Original assignee: GEOLOGRAPH Co
Current assignee: FIRST ASSET-BASED LENDING GROUP Inc C/O CONSOLIDATED ASSET MANAGEMENT COMPANY 120 NORTH ROBINSON OKLAHOMA CITY OK 73192
Priority date: 1956-08-13
Filing date: 1956-08-13
Publication date: 1960-11-08
Anticipated expiration: 1977-11-08

Description

Nov. 8, 1960 J. o. MELTON 2,959,371

RETRIEVING MECHANISM Filed Aug. 13, 1956 6 Sheets-Sheet 1 IN VENTOR James 0. Melton ATTORNEYS Nov. 8, 1960 J. o. MELTON RETRIEVING MECHANISM 6 Sheets-Sheet 2 Filed Aug. 13, 1956 IN VENTOR James aMeli/azz/ ifmfim,mm ATTORNEYS fiz Nov. 8, 1960 J. O. MELTQN RETRIEVING MECHANISM 6 Sheets-Sheet 3 Filed Aug. 13. 1956 INVENTOR Jam 0.Mcll'on BY mfim W W ATTORNEYS 1950 J. o. MELTON 2,959,371

RETRIEVING MECHANISM Filed Aug. 13, 1956 6 Sheets-Sheet 4 IN VENTOR Jmmas QMeLZon ATTORNEYS N v- 3, 196 J. o. MELTON 2,959,371

RETRIEVING MECHANISM Filed Aug. 13, 1956 6 -5l'ueets--$heet 5 INVENTOR James 0. Melton ATTORNEYS J. o. MELTON 2,959,371

RETRIEVING MECHANISM Nov. 8, 1960 6 Sheets-Sheet 6 Filed Aug. 13, 1956 e4 as 44 ATTORNEYS RETRIEVIN G MECHANISM James 0. Melton, Norman, Okla, assignor to The Geolo graph Company, Oklahoma City, Okla., a partnership Filed Aug. 13, 1956, Ser. No. 603,656

11 Claims. (Cl. 242107.3)

During an earth-boring operation, it is frequently neces-- sary to remove the drill string from the hole because of wear of the drill bit, to substitute stronger pipe or for other reasons. Upon removal, the drill string is raised and each section of pipe (usually three or four lengths) is successively removed, and either stacked vertically in the rig or laid down on a ramp. When the drill string is laid down on the ramp, only one length is laid down at a time. Because of the weight of the pipe and forces required to raise it, when it is removed from the bore hole it is permanently stretched and hence is longer than it was originally. The true dimension of each length of pipe is important data in order that a driller be able to determine the depth to which a hole has been drilled. Accordingly, as the drill string is removed measurements on the pipes are made and recorded to give the operator valuable logging information. Heretofore, as each length of pipe was removed from the drill hole, a special arrangement was necessary for measuring the pipe. This measuring operation, known as strapping, required each individual pipe to be measured by two men, each holding an end of a tape against the pipe to obtain its true elongated measure.

The present invention provides retrieving apparatus which greatly facilitates the strapping operation as the drill string is withdrawn from the bore hole by automatic control of a spring-biased measuring tape. Control of the tape is accomplished by having the tape wound on a spring-biased reel with the free end of the tape detachably connected to the swivel mounted on the traveling block of the rig. Thus as the drill string is elevated each section of pipe can be conveniently measured. As each section of pipe is elevated, the tape is drawn from the spring-biased reel storing energy in the spring mechanism. Since the apparatus is located on the derrick floor the pipe is measured by the operator pressing the tape against the pipe and reading and recording its measure. Control of the tape during up and down movement of the traveling block is achieved by the spring biasing action of the retriever mechanism. The mechanism includes a brake arrangement to place a drag on the spring-driven rewinding mechanism. This allows the spring to dissipate its energy slowing as rewinding of the tape proceeds. Thus, the described rewind control permits an easy smooth operation and prevents the possibility of the tape, upon failure or breakage, from snapping back or lashing around which could result in injury to an operator working in the area.

Another use for the present invention is assisting in the replacement or substitution of drill pipe. This operation is necessary when a different weight or size pipe is required in the bore hole. When the pipe used during one phase of the drilling operation is to be replaced, the drill nited States Fatent Q 2,959,371 Patented Nov. 8, i960 ice j nisrn is attached to the trolley. When pipe is to be laiddown, it is first pulled from the bore hole and uncoupledor broken and each section is hooked to the trolley and the traveling block of the rig is lowered. Since the trolley. line is inclined the bottom end of the pipe section will ride away from the derrick and the section will move. toward a horizontal position. During this action, the cable is payed out from the retriever mechanism which is located on the derrick floor near the head end of-the trolley line.

apparatus for automatically controlling the reeling out.

and retrieving of a graduated tape.

A further object of this invention is the provision'of a spring-biased tape or cable reeling mechanism in which the retrieving of a tape or cable is controlled so that it is. reeled in at a steady rate preventing snapback or backlash afterrelease.

Another object of this invention is to provide fora safety latch for holding a winding reel on a spring-biased shaft during the operation thereof.

Other and further objects of the present invention will become apparent from the following detailed description of a preferred embodiment of the present invention when taken in conjunction with the appended drawingsand claims in which:

Figure 1 is an elevational view showing the novel retrieving mechanism of the present invention as the same. is employed in connection with a drilling ring;

Figure 2 is a cross-sectional view of a retrieving mechanism showing the reel, the retriever spring, and the brake shoe arrangement;

Figure 3 is a fragmentary cross-sectional view taken along the line 3--3 of Figure 2 showing the gear arrangement for rotating the brake shoe mechanism, and the brake shoes and drum;

Figure 4 is a cross-sectional view taken along the line 44 of Figure 2 showing the reel mounted on the drive shaft;

Figure 5 is an end view of the reel showing a spring biased safety lock for holdingthe reel on the shaft;

Figured is a fragmentary cross-sectional view taken along line 6-6 of Figure 5 showing the push button safety lock mechanism for holding the reel on the shaft;

Figure 7 is an end view of the reel showing a springbiascd safety lock for holding the reel to the shaft which. is held in a locked position by centrifugal force; s

Figure 8 is an end View of the reel showing another. form of a spring-biased safety lock for holding the reel to the shaft;

Figure 9 is a cross-sectional view of an alternate form of brakeshoe and brake drum arrangement for control The pipe section is unhooked when the. trolley reaches the lower end of the trolley line and is in- 3 form of a spring-biased safety lock for holding the reel to the shaft.

In the drawings, Figure 1 shows a conventional type of drilling derrick for lifting and lowering drill strings used in the drilling operation. The drill string is raised and lowered by an elevating rig 11 which is controlled by a rigging operator. The drilling derrick is equipped with a pipe laydown mechanism 12 for laying down pipe and removing it from the drilling area as each length is removed from the bore hole. The pipe laydown mechanism has a trolley line or guide line 13 inclined downward and away from the drilling derrick. The trolley line is attached at one end to a post 14 and the other end passes through a stationary ring 15 which is held by a chain 16 and fastens to the framework of the drilling derrick. This arrangement provides for a trolley line that extends from a position near the floor where the drilling operation is being conducted to a ramp outside and away from the drilling area. At the end of the trolley line near the post 14 is a resilient stop 17. Operating on the trolley line 13 is a trolley 18 having a downwardly extending hook 19 for booking into the end of a pipe 20 after it has been removed from the drill bore. In normal operating position, the trolley is at the end of the trolley line within the derrick frame so that the free end of the suspended length of pipe can be pulled over by the uncoupler and hooked onto the hook of the trolley. This arrangement allows the pipe to rid the guideline as the elevator lowers the pipe and thus provides for its conveyance away from the drilling area. Positioned under the guideline on the floor of the derrick near the drill bore is a conveyor roller 21 upon which the top end of the pipe near the end of the laydown operation rests as it is guided from the drilling area. When the trolley 18 reaches the stop 17, the hook is removed from the end of the pipe by an operator and the pipe is allowed to roll down a pipe ram 22 to be stored for future use.

The trolley 18 is attached to a spring-biased cable 23 having graduations thereon controlled from a retriever box 24. The cable runs substantially parallel to the trolley line passing over a guide pulley 25 attached to the framework of the derrick. The graduations on the surface of the cable are arranged so that the cable when strapped to the pipe can be used to take its measurement.

As a length of pipe is conveyed-down the trolley line the spring-biased cable is unreeled which produces tensioning of the spring in the retriever mechanism. The tensioning of the spring places a retarding force on the trolley, which aids in keeping the hook in the end of the length of pipe. The farther the pipe is conveyed down the trolley line the more energy is stored in the spring. This energy is always available for returning the trolley to the derrick area.

The cable is controlled and handled by a reel 26 operatively connected to the retrieving mechanism in box 24. The reel for holding the cable is a drum shaped member having a flat face 27 at one end and a recessed opening at the other. In the periphery of the reel are two flat bottomed grooves 28 lying adjacent to each other to form a partition 29. In the bottom of one of the flat grooves is a hole 30 into which one end of the cable is held by a set screw 31. The partition between the adjacent grooves has a notch 32 therein to accommodate the transferring of the cable from one groove to the other during the winding and unwinding operation.

The hollow recessed portion of the reel is adapted to fit over an overhanging shaft protruding from within retriever box 24. Extending inwardly from the face 27 of the reel is a boss 33 having a bore therein for receiving a shaft 34. Across the end of the boss within the hollow portion of the reel are webs 35 offset to each other to form parallel drive surfaces for operatively connecting the reel to the shaft (see Figure 4). In the flat face 27 of the reel is a first milled slot 36 extending from bore 33 part way to the edge of the reel. Within the first slot is a second slot 37 centered with respect to the first slot and extending from bore 33 and terminating near the end of the first slot (see Figure 5).

The reel 26 is mounted on an overhanging shaft 34 and operatively connected thereto by drive pins 38 located in the shaft which bear against webs 35 (see Figure 2). This arrangement not only provides for the connecting of the reel to the shaft but also provides a stop against which the boss rests. The reel is retained on the shaft by a safety lock 39. The safety lock has a flat surface 40 and a projecting handle 41 at one end thereof. At thet other end is a circular shaped cut-out 42 having a turned-under portion 43 located in the center thereof which fits into second slot 37. The flat surface of the lock midway between the bottom and top has a circular notch 44. Around the periphery of the end of the shaft 34 are two

grooves

45 and 46 adapted to receive the circular shaped cut-out 42 of the safety lock.

In the face of the reel is located a pair of concentric holes (see Figure 6). The center hole 47 is drilled through a wall portion 48 of the reel, and the larger hole 49 is drilled only part way therethrough to provide a hole with a blind step therein adapted to receive a spring-biased safety latch locking arrangement 50. The locking arrangement has a lock button 51 with shaft extension 52 for actuating the button and a spring support shaft 53 for biasing the button outwardly with respect to the face of the reel. Around shaft 53 is located a spring 54 which rests at one end against the bottom of hole 49 and at the other end against the underface of button 51. This arrangement permits spring actuation of the button in and out of the blind hole 49. The fiat portion of the safety lock is held in slot 36 by a hold-down plate 55 which lies transverse to the movement of the safety lock. The plate is held in place by two bolts positioned so that the safety lock operates thtrebetween. The holddown plate has a hole 56 drilled therein in line with the axis of the hold-down button assembly 50 so that the shaft 52 extends through the hole in the plate while providing a hold-down for the button 51. The holding button is so arrangedthat, when assembled, it is spring biased outwardly and positioned so as to engage notch 44 in the fiat surface of the safety lock when the circular cut-out portion of the lock is in groove 45. By pressing the shaft extending out of hole 56 of the hold-down plate, the holding button is pushed out of contact with the notch 44 in the fiat surface of the safety lock 40, thereby allowing the safety lock to be lifted out of the groove 45 in the periphery of the shaft. The safety lock is spring biased towards the shaft by a spring 57 located in slot 37 and biased between the end of the slot and the turned-under portion 43 of the lock. This arrangement keeps the lock in constant engagement with the groove in the shaft.

Reel 26 is secured to outboard shaft 34 by pins 38 which contact webs 35 and provide a driving relation therebetween. The reel is prevented from coming off the shaft by the safety lock 39 engaging groove 45 around the periphery of the overhanging end of the shaft. The second groove 46 is located between the groove 45 and the end of the shaft so as to provide an additional safety catch to prevent the reel from jumping off the shaft in case the latch should become disengaged from groove 45. When the reel is moved forward so that the safety lock 39 engages outer groove 46, the webs 35 are disengaged from drive pins 38, allowing the reel to rotate freely on shaft 34.

Shaft 34 is supported in an overhanging compartment 58 which is attached to a spring-biased retriever compartment 59. The shaft 34 is rotatably mounted on front thrust bearing 69 and back bearing 61 both positioned within the overhanging compartment. The bearing 60 is held in a recess by a thrust plate 62, which is secured to the front end 63 of the overhanging compartment by suitable bolts.- Located around the shaft 34 in cover plate 62 is an O ring 64. A nut 65 threadedly engaging the shaft rests against the thrust bearing 60. The inboard end of the shaft projects into compartment 59 and is provided with gear teeth 66 cut in its periphery. Operatively engaging gear teeth 66 is a spur gear 67 mounted on a main shaft 68. The main shaft 68 is journaled at one end in'thrust bearing 69 located in hub 70 of the side of compartment 59. The thrust bearing 69 is held in the hub by a thrust plate 71 fastened to the hub by bolts 72. The other end of the main shaftextends into a brake shoe assembly compartment 73, being journaled in bearing 74 located in compartment 58 and in needle bearing 75 located in cover plate 76 of the brake shoe assembly.

In the main shaft 68 is a groove 77 adapted to hold one end of a flat spiral type tension spring 78. The other end of the tension spring is secured on a stud 79 in the compartment 59 so that rotation of the shaft 34 by paying out the cable from the reel causes winding of the spring thereby storing energy therein.

Mounted on the extension of the main shaft 68 in the brake shoe compartment 73 is a spur gear 80. In mesh with spur gear 80 is a spur gear 81 mounted on a needle bearing 82 which in turn is rotatably mounted on a fixed shaft 83. In mesh with spur gear 81 is a spur gear 84 which provides the drive for the brake shoe assembly. Spur gear 84 is rotatably mounted on a needle bearing 85. The needle bearing 85 is located on shaft 86 partway fitting into a recess in cover plate 76. Operatively connected to spur gear 84 is a brake shoe spider 87 adapted to rotate on shaft 86 (see Figure 3). The brake shoe spider 87 has two flat parallel surfaces 88 and cut-out portion so as to form an H-shaped configuration. Through each leg of the H-shaped configuration is a hole 89 adapted to receive a sliding bolt 90. On each of the parallel surfaces of the H-shaped configuration is a segmental brake shoe 91 adapted to form, when mounted on the spider, a circular member capable of rotating in a brake shoe drum 92. Each brake shoe is operatively connected to a parallel face of the spider by the two holding bolts 90. Each holding bolt has a spring positioned between the head thereof and the inner surface of a leg of the cut-out portion of the H-shaped configuration. This arrangement permits spring biasing of the brake shoes away from the parallel surfaces of the spider so that centrifugal force during turning of the spider causes the brake shoes to frictionally engage the surface of the drum thereby retarding the action of the spring to effect a control of the rate of rewinding of the cable onto the reel.

An alternate type of brake shoe assembly is shown in Figure 9. In this assembly a circular spider 94 is opcra-' tively connected to spur gear 84 by a set screw. The circular spider has a groove 95 therein adapted to receive two evenly spaced brake shoe elements 96 (see Figure 10.) Each brake shoe element is pivoted about a. pin 97 andlisspring biased outwardly by a spring 98 so that the face of the shoe rests lightly against the face of the brake, shoe drum 92. By pivoting both shoes opposite to each other, the rotation of the spider housing causes each shoe by centrifugal force to move outwardly, thereby placing a frictional drag on the retrieving mechanism being operated by the tensioning spring.

An alternate type of safety lock for holding the reel on the shaft is shown in Figure 7.. The face 27 of the reel has a milled-out slot 99 offset to the diameter of the face. The slot extends from partway around the circumference of the hole for the shaft to a point near the edge of the reel. Centrally located with respect to the slot 99 is a second slot 100. The safety lock has a flat portion 101 with an outwardly extending handle 102. In one side of the flat portion is a circular notch 103. In the lower corner away from the handle and on the side opposite to the position of the notch is a circular cut-out 104 designed to engage groove 45. Extending inwardly is-a lug 105 positioned so as to ride in the slot 100. The .safety lock is held in position by a hold -down plate 106 secured to the face of the reel by twobolts. Positioned in the hold-down plate is a hole 107 in line with the center line of the push button locking mechanism 50 through which the shaft 52.- extends. A spring 108. is re-, tained in the slot biasing the safety lock mechanism by spring action on lug so that the circular cut-out 104 is urged in the direction of engagement with groove 45. In this position the safety lock button is engaged in notch 103.

Another variation of the safety latch forming a part of this invention is shown in Figure 8. The face 27 of the reel has a milled slot 110 with parallel sides offset with respect to the diameter of the reel. The slot extends for a distance beyond the bore for shaft 34 so that the ends thereof come near the edge of the reel. Within the slot 110 is a second slot 111 centered with respect to the. width of'slot 110 and positioned above the bore in the reel for the shaft. In the'slot 110 is a safety lock having a fiat surface 112 with a circular cut-out portion 113 on its side. The position of the slot and the circular cut-out in the fiat surface is suchthat movement of the safety lock in the slot will cause the edge of the circular cut-out to engage groove 45 in the shaft 34. A spring 114 is positioned in the slot lll'and rests on lug 115 providing a biasing of the safety lock so as to keep the circular cut-out in groove 46. The safety lock is held in the slot by two hold-down plates 116 having bolts 117 for securing the plates to the reel. The heaviest portion of the safety lock is away from the locking edge of the circular cut-out so that rotation tends to cause theflock to lock tighter.

A further variation of the safety lock forming a part of this invention is shown in Figure 12. The face 27 of the reel has a milled-out slot 118 with parallel sides and semi-circular ends. The slot is centrally located with respect to the face of the reel through which the shaft 34 fits and extends for a distance beyond the bore for the shaft so that the ends thereof come near the edge of the reel. Within slot 118 is a second slot 119 centered with respect to the longitudinal axis of slot 118 and extending from each side of the bore for the shaft 34. Slot 118 is adapted to receive a safety lock having a fiat surface 120 with a hole 121 centrally located therein and an outwardly turned handle 122. The hole is larger than the shaft 34 so that the safety lock can be moved within slot 118 to permit the edge of the hole to en-. gage and disengage slot 45 in the periphery of shaft 34. At the edge of the hole 121 is a turned-under portion 123 which fits into slot 119 and rides therein. Between the blind end of the slot 119 and turned-under portion 123 is a spring 124 which biases the edge of the hole 121 of the safety look into engagement with slot 45 in the shaft 34. The safety lock is held in slot 118 by two hold-down plates 125 which are secured to the face of the reel by bolts 126.

An alternate form of braking arrangement is shown in Figure ll in which the brake 's'hoe assembly is located on the reel shaft 34 in the outboard compartment 58. In this arrangement, a circular spider 127 is operatively connected to reel shaft 34 and held thereon. The circular spider has a circular groove 128 therein adapted to receive two evenly spaced brake shoe elements 129. Each brake shoe element is pivoted about the pin 130 and is spring biased outwardly .by a spring 131 so that the face of the shoe rests lightly against the face of a brake shoe drum 132 formed around the inner surface of out'-. board compartment 58. The brake shoe arrangement, as shown in Figure 11, is the equivalent of the brake shoe arrangement shown in Figures 9 and 10, except that this arrangement is operatively connected to the shaft holding the reel and utilizes the inner surface of the outboard compartment as the brake shoe drum to effect a frictional drag on the spiral tensioning spring during rewinding of the cable. Also, the spiral tensioning spring arrangement is the same as shown in Figure 2 except that the main shaft 68 does not extend into a brake shoe compartment because the compartment for housing the gear train driving the brake shoe element is unnecessary since the brake shoe element is located on the reel shaft.

It is understood that the brake shoe arrangement illustrated in Figure 2 can be used in place of the brake shoe arrangement as shown in Figure 11. Using the arrangement as shown in Figure 2, the brake shoes are located on the reel shaft, spring biased inwardly, and when the reel shaft turns at an excessive speed of rotation, the brake shoe elements by centrifugal force contact a brake shoe drum formed around the inner surface of the outboard compartment 58.

Also, an alternate arrangement is shown in Figure 11 for journaling the reel shaft 34 in the outboard compartment by the use of snap rings 133 which fit into grooves around the shaft 34 adjacent to

bearings

60 and 61. By the use of the snap ring, the nut 65, threadedly engaging the threaded portion of shaft 34, as shown in Figure 2, is eliminated.

In operation, the pipe 20 is removed from the drill bore by the derrick rig 11 and uncoupled by an operator so that the lower end of the pipe is free. In the specific embodiment of this invention illustrated in Figure 1, the end of the pipe is placed on hook 19 of a trolley 18 as the rig is slightly lowered. The retrieving cable is attached to the trolley and provides a tensioning force in the direction opposite to the travel of the trolley down the trolley line. As the pipe is lowered, the trolley travels down the trolley line pulling with it the cable 23. When the pipe has assumed a laydown position, the upper end of the pipe is then resting on roller 21. At this point, the cable has been unreeled by the travel of the trolley and the spring in the retriever mechanism wound. The operator then simply straps the cable against the end of the pipe and records its measure. The pipe is unhooked and allowed to roll down the pipe ramp to a storage pile where it is ready for future use. At this point the spring-biased retrieving mechanism winds the cable pulling the trolley up the inclined trolley l.ne to position it for the removal of another length of pipe. The retrieving mechanism, therefore, serves as a control for the trolley as well as providing the motivating force to return the trolley after the pipe is laid down. It also serves as a means by which the measuring of the length of pipe can be conducted in a convenient and easy manner heretofore unknown in well drilling operations.

In cases where pipe removed is to be replaced in the bore hole, the end of the retriever cable is passed under a roller as the cable comes off the reel and is hooked onto the end of the pipe before it is raised from the bore hole. As the pipe is raised from the bore hole, the retriever cable is payed off the reel. The unreeling of the cable increases tension in the retriever mechanism storing energy for winding the cable on to the reel. When the length of pipe has been removed from the bore hole and uncoupled, the operator straps the cable against the pipe to record its true length. After the strapping operation, the retriever cable is unhooked from the top end of the pipe and allowed to return, the motivating force for returning being supplied by the energy stored in the retriever mechanism by the unreeling of the cable during the drawing of the pipe from the bore hole. The pipe then is placed in a stand ready for replacement in the bore hole as required.

When the cable is reeled by the reeling mechanism, the rate of return is controlled by the brake shoe arrangement, which places a drag on the spring biasing of the reel to prevent the snapping back of the cable. The unwinding of the cable from the reel causes the reel shaft to operate the gear train spring biased by a spiral tensioning spring positioned between the main shaft of the gear train and the retriever mechanism compartment. As more cable is payed out, the tension of the spring is increased. This arrangement allows for the storage of energy which is continually built up as the unreeling of the cable progresses. Upon release of the cable from the end of the pipe or the unhooking of a length of pipe from the trolley, the cable under spring tension is rewound on the reel. As soon as the spring-biasing mechanism picks up sufficient momentum to rotate at an excessive speed, the brake shoes, located in the brake drum operatively connected to the gear train, are forced by centrifugal force outwardly against the surface of the brake shoe drum. The contacting of the surface of the drum with the face of the brake shoes places a drag on the spring motivated reeling of the cable. This frictional drag by the brake shoes controls the rate of return of the cable so that the reeling in of the cable is never allowed to proceed at a high rate of speed.

In the alternate form of braking arrangement, as shown in Figure 11, the brake shoe elements are operatively connected to the shaft holding the reel so that excessive rewinding of the shaft by the spiral tensioning spring causes the brake shoe elements by centrifugal force to engage the brake shoe drum formed around the inner periphery of the outboard compartment into which the reel shaft is journaled.

The reel is held on the shaft by a safety lock which allows for easy removal or quick assembly of the reel to the shaft. The positive locking arrangement holds the slots in the boss of the reel in engagement with the drive pins in the shaft. The safety lock is spring biased in the slot in the face of the reel so that the cut-out portion in the bottom of the lock engages the groove in the periphery of the reel shaft. The notch in the side of the latch allows the spring-biased button to engage the notch, thereby providing a safety catch when the lock is in position. The removal of the reel from the shaft is accomplished by first pressing the shaft, which extends through the hole in the hold-down plates, to force the safety button inwardly and out of contact with the notch. Then the lock is raised by pulling up on the handle which lifts the circular cut-out of the lock out of engagement with the groove around the periphery of the shaft leaving the reel free to be pulled off the shaft out of engagement with the driving pin.

In the alternate form of safety lock arrangement, the face of the safety lock has a circular opening centrally located therein larger than the shaft so that a portion of the periphery of the hole in the face of the safety lock can be brought in and out of engagement with the groove around the periphery of the shaft. This arrangement allows the operator to press down on the handle of the safety lock compressing the biasing spring and centering the hole in relation to the face of the shaft so that the reel can be removed therefrom.

It is understood that the retrieving mechanism, illustrated in this invention, may be used wherever any line retrieving job may be encountered during a well drilling operation.

Although the present invention has been shown and described with reference to a referenced embodiment, nevertheless various changes and modification that would be obvious to those skilled in this art from a knowledge of the teachings of the present invention are deemed to be within the scope and contemplation of the invention.

What is claimed is:

l. A retriever apparatus comprising a winding and unwinding reel, a first shaft rotatably mounted in said apparatus and having a peripheral groove around one end of said first shaft, said reel being removably mounted on said first shaft for driving engagement therewith, the other end of said first shaft having a gear portion thereon, a cable wound on said reel, a second shaft rotatably mounted within said retriever apparatus in spaced and parallel relationship with said first shaft, a gear mounted on said second shaft in driving relation therewith, said gear meshing with the gear portion on the end of said first shaft, a spring biasing means connected to said Seeond shaft and to a fixed portion of said retriever apparatus, said spring biasing means being tensioned by the unwinding of said cable from the reel, a brake means operatively connected to said first shaft whereby excessive speed of rewinding of said reel by the spring biasing means produces a frictional drag on said rewinding opera tion, and a spring biased safety latch located in the face of said reel for retaining said reel on said first shaft, one end of said latch defining a circular cut-out portion therein adapted to fit into said groove of said first shaft.

2. An apparatus as claimed in claim 1 in which the one side of the safety latch defines a circular notch portion adapted to receive a spring biased button located in the face of the reel for holding the safety latch in a locked position in said groove.

3. An apparatus as claimed in claim 2 in which the circular cut-out portion is located in the lower corner away from the circular notch portion.

4. An apparatus as claimed in claim 1 in which the circular cut-out portion is located in one side of the safety latch.

5. An apparauts as claimed in claim 1 in which the latch defines a circular cut-out portion located centrally therein.

6. Apparatus for removably mounting a reel on a shaft comprising a reel, a shaft upon which the reel is maintained in driving relation therewith, said shaft having a groove around the periphery of one end of said shaft, a spring biased safety latch located in the face of said reel for maintaining said reel on said shaft, one end of said latch defining a circular cut-out portion therein adapted to fit in to said groove.

7. An apparatus as claimed in claim 6 in which the one side of the safety latch defines a circular notch portion adapted to'receive a spring-biased button located in the face of the reel for holding the safety latch in a locked position in said groove.

8. An apparatus as claimed in claim 7 in which the circular cut-out portion is located in the lower corner away from the circular notch portion.

9. An apparatus as claimed in claim 6 in which the circular cut-out portion is located in one side of the safety latch.

10. An apparatus as claimed in claim 6 in which the latch defines a circular cut-out portion located centrally therein.

11. Apparatus as set forth in claim 6 wherein said shaft is provided with a second groove into which said circular cut-out portion is adapted to fit whereby said reel may be freely rotated relative to said shaft.

References Cited in the file of this patent UNITED STATES PATENTS 1,857,642 Jones May 10, 1932 1,867,743 Hopkins July 19, 1932 2,133,551 Logan Oct. 18, 1938 2,237,465 Zimmerman Apr. 8, 1941 2,293,755 Joabson Aug. 25, 1942 2,425,292 McCoy Aug. 12, 1947 2,539,751 Olsen Jan. 30, 1951 2,637,510 Gill May 5, 1953 2,647,341 Donnell Aug. 4, 1953 2,735,629 Hicks et a1. Feb. 21, 1956