US2664175A - Hook locking mechanism - Google Patents

Description

Dec. 29, 1953 R. K. HERTEL ErAL HOOK LOCKING MECHANISM Original Filed April 28, 1945 sets-Sheet l Dec. 29, 1953 R. K. HERTEL EIAL 2,664,175

HOOK LOCKING MECHANISM Original Filed April 28, 1945 4 Sheets-Sheet 5 agtto'mzyA 1953 R. K. HERTEL ETAL 2,664,175

HOOK LOCKING MECHANISM Original Filed April 28, 1945 4 Sheets-Sheet 4 Patented Dec. 29, 1953 HOOK LOCKING MECHANISM Richard K. Hertel, Winston-Salem, N. 0., and Garth F. Nicolson, South Gate, Calif., assignors to Byron Jackson 00., Vernon, Calif., a corporation of Delaware Original application April 28, 1945, Serial No. 590,940. Divided and this application January 6, 1949, Serial No. 69,454

12 Claims.

This application is a division of our copending application Serial No. 590,940, filed April 28, 1945, on Spring Hook, now Patent No. 2,506,593.

This invention relates to spring hooks of the type employed in oil well drilling operations, and particularly to locking mechanisms for use therewith.

A hook of the foregoing type is used to suspend a string of drill pipe or casing in the well, and is equipped with a compression spring which serves to raise a stand of drill pipe as it is disconnected from the string and thus avoid damaging the threads of the tool joints or couplings. In order to enable the spring to support the weight of a stand of drill pipe without undue sagging, it is customary to precompress the spring during assembly of the hook. Heretofore it has been the general practice to obtain this precompression of the spring by means of a nut threadedly engaging the upper end of the hook shank and engaging the spring to compress it between the nut and a shoulder in the housing of the hook. In addition to its function of applying precompression to the spring, according to usual practice the nut is also pro-' vided with a shoulder which is adapted to engage a shoulder in the housing upon predetermined further compression of the spring under load, thus to limit the compression of the spring and to transfer the major portion of the load .from the shank directly to the housing.

The foregoing arrangement has the inherent disadvantage of subjecting the threads of the shank and nut to the full load imposed on the hook, a condition which is objectionable from several standpoints. In the first place, the root diameter of the threads is necessarily quite large :in order to provide a shank of sufficient section (as much as six inches in diameter in heavy 'duty hooks), thus requiring the application of considerable force when screwing the nut onto the shank, in order to overcome friction between the large surface area of the threads and at the same time compress the spring to a precompression force of the order of 2000 pounds. Furthermore, a threaded connection under full hook load introduces a potential weakness because of the possibility of the nut working loose and backing ofi as the result of vibration, unless adequate locking means are provided. Also, in view of the difficulty in providing adequate lubrication of the threads, they are likely to become galled, or corroded from the humid atmosphere prevailing in many oil fields. This may necessitate replacement o an nt r S a n case the threads are damaged beyond safe limits of reworking, or, as occasionally happens, it is impossible to unscrew the nut and resort must be had to cutting it off with a torch. These and several other less serious objections make it highly desirable to eliminate the threaded connection subjected to the full load imposed on the shank.

It is a principal object of this invention to provide a locking mechanism particularly adaptable for use with a spring hook which in fact does avoid the aforesaid threaded connection but adaptable also for the aforedescribed conventional spring hook.

It is a further object of this invention to provide said locking mechanism of novel and improved means whereby to releasably lock the shank and housing member of the hook against relative rotation.

It is still a further object of this invention to provide means whereby there is no danger of the locking element being either locked or released accidentally.

Another object of the invention is to provide the locking mechanism in a complete, operative sub-assembly whereby its operation may be checked before incorporating said locking mechanism in the spring hook itself and whereby replacement problems are minimized in that replacement in a hook in the field with a locking assembly previously assembled is possible.

Further objects of the invention will appear hereinafter.

In the drawings:

Figure 1 is a longitudinal sectional view of a hook embodying the invention;

Figure 2 is a side elevational view taken at right angles to Fig. 1, with parts broken away to illustrate certain novel features of the invention;

Figure 3 is a view, partly in elevation and partly in longitudinal section, of a modified form of hook embodying the invention;

Figure 4 is a transverse sectional view taken in line IV-IV of Figure 1, illustrating the novel swivel locking mechanism:

Fi ure 5 is an end elevation of the swivel look, as viewed from the lane of line VV of Fi ure 4; v Figure 6 is a vertical sectional view taken on the broken section line VIVI of Figure 4;

Fi ure '7 is a view similar to Figure 6, showing the swivel lock in looking position:

Fi ure 8 is a view similar to Figures 6 and '7 but showing the po ition assumed by the parts when the locking element is moved toward looking position but is out of registry with a cooperating locking recess;

Figure 9 is a side elevation of the swivel lock sub-assembly;

Figure 10 is a sectional view taken on line X--X of Figure 9; and

Figure 11 is a sectional view taken on line XIXI of Figure 9, showing on an enlarged scale the swivel lock in the position illustrated in Figure 1.

Referring to Figures 1 and 2 of. the drawings, a hook body I is connected by a pivot pin 2 to the lower extremity of a shank. 3 which is supported in a housing 4 for rotation and axial movement relative to the housing. The hook body I may be either a single hook or may be of the so-called Triplex design, as shown, with a main central load-receiving recess 5 (Figure 2) to receive a swivel bail or other single load member, and a pair of laterally ofiset recesses 6 and 8' (Figure 1) to receive the usual elevator links. The hook body may, if preferred, be of "Duplex" design, incorporating only the link recesses 6 and 5 and omitting the main recess 5. A bail 1 is suitably attached to the upper end of the housing i for connecting the hook to the usual travelling block.

The shank 3 is yieldably supported by the hous ing for limited axial movement relative thereto by one or more helical compression springs, herein three in number, designated 8, 9 and In. The springs are supported at their lower ends on the upper surface I of a swivel ring l2 rotatably supported on a thrust bearing |-3 in the lower portion of the housing. As shown most clearly in Figures 2 and 4, the major portion of the shank 3 is fiattened on diametrically opposite sides at M and I5, and the swivel ring [2 is provided with an opening [6 through its lower portion, conforming in shape to the flattened portion of the shank, whereby the shank is free to move axially through the ring but is confined against rotation relative thereto. The opening l6 terminates at its upper end in a transverse shoulder adapted to cooperate with downwardly facing shoulders l3 and I9 formed on the shank at the upper extremities of the flattened sides l4 and IE, to limit the downward movement of the shank. Above the shoulder H, the opening in the swivel ring I2 is cylindrical in cross-section to accommodate the cylindrical upper portion 20 of the shank.

It has been cu tomary heretofore to threadedly secure a nut to the upper extremity of the hook shank, and to limit the downward movement of the shank by engagement of the under surface of the nut with an upwardly facing stop shoulder formed on the housing. The objections to this practice have been set forth hereinabove. In the present in tance, p-recompression of the springs 8, 9 and I0 is effected by means of an element threadedly connected to the upper extremity of the shank, but contrary to usual practice, this element is wholly independent of the means for limiting downward movement of the shank and hence it i not subjected to the full load supported by the hook. Th i latter function i performed by the downwardly facing shoulders l8 and I9 forming an integral part of the shank.

Referring to Figure 1, a threaded stem 2|, of considerably smaller size than the shank 3, extends upwardly from the upper extremity of the shank 3. For convenience, the stem is formed as a separate element threadedly secured at 22 to the shank and locked a ainst inadvertent unscrewing by a locking pin 23'. It will be appreciated, however, that it could equally well be formed as an integral extension of the shank 3, or, if separate, it could be attached thereto by other means than that shown. A sleeve-like member 24 is telescoped over the stem 2|, the major portion of the member 24 being of substantially the same overall diameter as the shank 3, and the upper portion thereof being enlarged at 25 to loosely fit the bore 26 of the housing 4. A downwardly facing shoulder 2'! is thus formed on the member 24 for engagement with the upper ends of the springs 8, 9 and II).

It will be noted that the member 24 is provided with a deep cup-shaped recess 28 for the reception of an elongated nut 29 threadedly secured to the stem 2| and bearing against the bottom wall of the recess 28 to rigidly secure the member 24 to the shank 3. If desired, a bearing 30 may be interposed between the lower surface of the nut and the base of the recess to avoid undue friction between these surfaces while the nut is being made up on the stem to apply precompression to the springs.

As shown most clearly in Figure 2, a ring 3| is secured by a transverse pin 32 to the portion of the shank 3 projecting below the housing 4. The purpose of this ring is to provide an abutment on the shank engageable with the bottom wall. of the housing to limit the upward movement of the shank as it is urged upwardly by the springs.

The mode of assembly of the hook is as follows: The bearing I3 is first placed on its seat in the housing, and the swivel ring I2 is then inserted into position on the bearing. The shank 3, with the threaded stem 2| attached thereto, is then inserted through the upper end of the housing, with its lower portion projecting through the opening IS in the swivel ring. The shank ring 3| is then applied to the shank from the lower end thereof and secured in place by the pin 32. The springs 8, 9 and I0 are then seated on the swivel ring [2 in nested relation, whereupon the member 24 is applied to the upper end of the shank. It will be understood that the free length of the springs is considerably greater than the precompressed length shown in Figure 1, and the threaded portion of the stem 2| is made of sufficient length to permit the nut 29 to be started on the stem when the springs are fully expanded. As the nut is threaded downwardly on the stem, the springs are compressed between the shoulder 2'! on the member 24 and the upper surface II of the swivel ring, the engagement of the shank ring 3| with the lower surface of the housing 4 restraining the shank against upward movement. During this operation the shank is held against rotation in any desired manner, such as by inserting a bar through the pivot pin hole in the lower end of the shank. The shank, swivel rinf, l2, springs, sleeve member 24 and stem 2| constitute a unit between the elements of which no relative rotation takes place, the thrust of the nut being applied to the member 24 through the bearing 30. After the springs are compressed the desired amount, the nut 29 is locked to the stem 2| by a locking pin 33. A cover plate 34 is then secured to the upper end of the housing 4, and the ball 1 is then attached to the housing.

It will be apparent from the foregoing description that the threaded connection between the nut 29 and the stem 2| is subjected only to the force exerted by the spring when the latter is under maximum compression. This force is a predetermined amount, limited by engagement of the shoulders l8 and IS on the shank with the shoulder 11 on the swivel ring [2. This force seldom exceeds 5000 pounds, which is relatively small in comparison with the total load imposed on the hook, which may be several hundred tons. Hence the stem 2| may be of relatively small diameter, thus greatly reducing the torque required to overcome friction between the threads as the nut is made up. Of greater importance is the fact that even if the nut 29 should back off when the hook is under full load, no serious consequence would ensue, such as dropping the load, which would occur if the nut were subjected to the full load.

The foregoing structure is not claimed herein but has been claimed in a copending application filed by ourselves April 28, 1945, Serial No. 590,940 for Spring Hook, now Patent No. 2,506,593.

Referring now to the novel means for releasably locking the shank against rotation relative to the housing, it will be observed that a series of locking recesses 35 are provided in the outer periphery of the swivel ring l2. Only two of these recesses are shown in the drawings, but it will be understood that as many as are desired may be provided, preferably at 45 angular intervals. A locking mechanism, generally designated 36, is mounted in a suitable recess in the housing, and includes as an element thereof a locking element 3! selectively engageable with any one of the recesses'35.

The locking mechanism is constructed as a unitary sub-assembly which may be assembled separately from the remaining parts of the hook, and then inserted as a unit into the housing 4. This sub-assembly is best illustrated in its entirety in Figure 9, and in Figure 4 it is shown mounted in the housing. As shown in the latter figure and in Figure 1, the housing 4 is enlarged to provide a recess 53 to receive the sub-assembly. At one end of the recess the housing is bored at 39 to form a centering surface which is engaged by a corresponding surface on a unitary frame 46 in which the elements of the locking mechanism are mounted. At the opposite end of the recess the housing A is bored at Al to form a centering surface for a cap 42 which is threadedly connected at 43 to the adjacent end of the frame all. The locking mechanism is completely assembled except for the cap 42, and is then inserted into the recess 38 from the end adjacent the large bore 39, until the flanged portion M of the frame 45 engages the housing. lhe cap i2 is then threaded onto the opposite end of the frame to secure the frame rigidly to the housing. The cap may be locked by a look-- ing pin 4'5 extending through the cap and loosely engaging a socket 46 in the frame.

An operating member or crank ti is journaled at its opposite ends at 48 and 49 in the frame 40, for oscillation about its axis through an arc of approximately 45. As shown in Figures 4, 6 and '7, the locking element is formed integral with a sub-frame 50' which is journaled on the crank :i'i at 5! and 52. A segmental projection 53 is formed on the mid-portion of the crank 41, and a similarly shaped recess 54 is provided in the internal surface of the sub-frame 58. However, the end walls 55 and 55 of the recess 54 embrace an are which is slightly greater than the arcuate extent of the projection 5s as defined by the end walls 57 and 58 thereof, whereby there is a slight lost motion between the crank and the subframe.

As shown in Figures 4 and 5, an enlarged head 59 is formed on one end of the crank 41 exteriorly of the frame 40 where it is accessible for manual manipulation. A pair of oppositely projecting wings 60 and GI are provided on the head, the upper surfaces of the wings being concave to facilitate engagement thereof by the hooked end of a releasing rod, whereby a downward pull on the rod will serve to oscillate the crank about its axis in either direction. The head 59 is positioned within a recess in the housing 4, and to facilitate engagement oflthe releasing rod with either of the wings 60 and 6 l, a narrow, elongated slot or groove 82 is formed in the outer wall of the housing for reception of the hooked end of the rod. An upwardly extending projection 63 on the head serves to guide the rod from the groove 62 into engagement with the proper wing, depending on which position the crank occupies.

When the head 59 is in the solid-line position of Figure 5, the locking element 31 is in released position and the segmental projection 53' on the crank 41 occupies the position shown in Figures 1 and 11, with its upper end surface 58 abutting the end wall of the r cess 54. Upon oscillation of the crank 41 in a clockwise direction, it first moves through a small arc of approximately 10 to 15 of lost motion without effecting movement of the sub-frame 50. Upon engagement of the end surface 51 with the end wall 55, as shown in Figure 6, subsequent rotation of the crank is accompanied by corresponding movement of the sub-frame 50 to move the locking element 31 into engagement with one of the locking recesses 35 in the swivel ring 12, as shown in Figure 7. The purpose of the lost angular motion between the crank 4*! and the sub-frame 50 is to effect the release of latch means normally latching the subframe in either of its positions, as will be presently described.

It will be observed with reference to Figures 4 and 10 that a helical torsion spring 65 surrounds a portion of the sub-frame 50 adjacent the locking element 31, one end 66 of the spring abutting a surface 61 on the locking mechanism frame 40, and the other end 58 of the spring engaging a lug 69 on the sub-frame 50. The subframe 50 is thus at all times urged by the spring 65 toward its locking position wherein the locking element 31 engages one of the recesses 35 in the swivel ring 12.

The latch means for positively latching the sub-frame in either of its two extreme positions comprises a pair of latch members I0 and H both pivotally mounted on a common pivot pin 12, the opposite ends of which are supported in aligned bores 13 and H in the sub-frame 50. Thus the latch members are mounted for oscillation relative to the sub-frame about the axis of the pin 12, and they also move bodily with the sub-frame when the latter is oscillated about the axis of the crank 41. It will be noted by reference to Figures 6, 7, 8, 9 and 11 that the latch members 10 and II are of identical construction, but the member H is mounted on the pin 12 in inverted relation to the member 10. Lugs 15 and it are formed on the adjacent sides of the latch members (Figure 9) to provide abutments for the opposite ends of a torsion spring 11 which thus urges the member 10 in a clockwise direction and urges the member H in a counterclockwise direction, as viewed in Figures 6, 7, 8 and 11. Referring to the latter figures, it will be noted that a cam 18 is formed on the member 10 and a similar cam 19 is formed on the member H. Coopcrating cams 80 and 8| are formed on the crank 41 in the planes of the cams l8 and 19, it being noted that the cam 80 engages the under surface of the cam 18, and that the cam 8| engages the upper surface of the cam 19. The torsion spring 11, urging the latch members in opposite directions, maintains the cooperating cam surfaces in constant engagement.

The latch member '10 includes a latch finger 82 which projects outwardly through a window 50' in the sub-frame 50 and has a latching surface 83 engageable with a cooperating surface 84 on the frame 40 to latch the sub-frame in released position, as shown in Figure 11. The finger 82 is so shaped as to provide a recess 85 to receive the adjacent portion of the frame 49 when the sub-frame and latch members are moved to the locked position shown in Figure '7. The latch member 1| is similarly provided with a finger 86 having a latching surface 81 engageable with a cooperating surface 88 on the frame 40 to latch the sub-frame 50 in locked position (Figure 7), and is so shaped as to provide a recess 89 to receive the adjacent portion of the frame 40 when the sub-frame 50 and latch members are moved to released position (Figure 11).

The operation of the locking mechanism and its latch members is as follows: Assuming that the parts are in the released position shown in Figure 11 and it is desired to lock the shank 3 and hook body against rotation relative to the housing 4, the operator engages the releasing hook with the wing 6| (Figure and pulls downwarly to move the crank 41 in a clockwise direction. The initial movement of the crank does not effect movement of the sub-frame 4% until the surface 51 engages the surface 55, but during this initial clockwise movement of the crank the cam 80, acting on the cam 78, moves the latch member 10 from its latching position to the unlatched position shown in Figure 6. Inasmuch as the torsion spring 85 constantly urges the sub-frame 50 in a clockwise direction, as soon as the latch member 10 has been moved completely out of the window 58 the sub-frame is rotated by the spring 65 into the locked position shown in Figure 7. Upon reaching this position, the finger 88 of the latch member 1| clears the lower wall of the window 50' and is urged by the torsion spring 11 into latching engagement with the surface 88. The sub-frame 50 and its locking element 31 are thus positively held in locked position until the latch member 1| is released by manual manipulation of the crack in a counterclockwise direction;

It frequently occurs that when locking the hook again swivelling, the locking element 3'! is not in registry with one of the locking recesses 35 when it is moved toward locking position. in that event, the locking element moves inwardly until it engages the outer wall 35' (Figure 8) of the swivel ring. With the sub-frame in this position, the finger 82 of the latching member '59 is disposed in non-latching position outside the frame 46, and hence the locking element 3'! is free to snap into a recess 35 under the influence of the spring 65 upon rotation of the shank 3 and swivel ring I2. When this occurs, the finger 88 on the latch member 7| clears the lower wall of the window 50 and snaps into latching en gagement with the surface 88 under the influence of the torsion spring 11. The parts thus assume the positions illustrated in Figure'l.

When it is desired to release the locking mechanism to permit free swivelling of the shank 3 and hook body I relative to the housing 4, the operator engages the releasing hook with the wing 68 (Figure 5) and pulls downwardly to move the crank 41 in a counterclockwise direction. Initial movement of the crank causes the cam 8| thereon to act on the cam $9 on the finger 1| and swing the latter in a clockwise direction to release the latching surface 3'! from the surface 38. Full release of the latch member 5| occurs concurrently with engagement of the upper end surface 58 of the projection 53 with the upper end wall 56 of the recess Thereupon continued movement of the crank rotates the subframe 46 and its locking element into released position, and when this position is reached the finger 82 on the latch member 10 clears the upper wall of the window 50' and snaps into the window in latching engagement with the surface 84 under the influence of the torsion spring 7. The locking element is thus securely latched against inadvertent return to locking posi-- tion.

It will be apparent from the foregoing description of the locking mechanism and its mode of operation, that there is 1 .0 d of the locking element being either locked. or releas d acidentally as the result of a sudden jar or vibration, because of the positive latch in both positions. Positive latching in loo 5. position is specially desirable inasmuch as t has be ound that a lock which is merely sprin" into locked position is occasionally rele by the whipping and the vibration to which the hook is subjected during drilling. The swivel lock in the hook is relied on to hold the rotary swi'v 1 body against rotation, which tends to occur due to rictional drag of the swivel stern in s 1mg box. If the swivel lock should a it become released, the rotary swivel y ro several times before this condition is noticed, thus wrapping the rotary hose about the Kelly and possibly severing the hose.

The construction of the lock a complete-operative sub-asst advantage inasmuch as it perr as a separate unit, and enables the housing 4. It is also feasible to con plete line of hooks of Varying cape. with identic 1 locking mechanisms, and, by providing a complete, unitiaed sub-asseznbly, a few sub-assemblies at a distribution point are suii-ient to care for the replacement needs of a large number of hooks of different capacities. The replacement in the field of a worn or damaged locking mechanism is also greatly facilitated by this construction.

In Figure 3 there is illustrated a different type of hook embodying the features of this invention. This hook is of the so-calle l Connector type, and in most respects constitutes an inverted arrangement of the construction shown in Figs. 1 and 2. Thus it will be observed that the shank projects from the upper end or the housing Ga, instead of from the lower end thereof as in Figures l and 2, and the projecting end the shank is connected by a pivot pin 2a to a ball or c evis la by which the hook may be suspended from the usual travelling block. Since in this construction the housing 4a corresponds functionally to the hook body of Figures i it is urovided with a pair of diametrically opposite link receiving recesses 8a and 8b. A bail 5a. may be suitably connected to the lower end of the housmg to support a single-bail elevator or other load.

1 GODS.-

It will be understood by those familiar with oil field operations that in the use of this type of hook the rotary swivel is supported by the drill pipe elevator which is attached to the elevator links supported in the recesses 6a and 6b, instead of having the swivel bail supported in the main hook recess of Figure 2.

It will be observed from a comparison of Figures 1 and 3 that the internal construction of Figure 3 is substantially identical with but inverted with respect to that of Figure 1. Thus the housing 4a is resiliently and rotatably supported by the shank 3a through the intermediacy of nested compression springs 8a and 9a interposed between a sleeve member 24a attached to the shank and a swivel ring IZa journaled in the housing. A thrust bearing I3a is interposed between the swivel ring and the housing to permit free rotation of the housing when under full load. The shank 3a is flattened on opposite sides at Ma and I5a and passes through a similarly shaped opening [15a in the swivel ring, to provide a slidable and non-rotatable connection between the shank and the swivel ring. The lower extremity of the shank is of full circular crosssection at 20a, and thus provides a pair of upwardly facing shoulders at the lower end of the flattened section, one of these shoulders being shown at 18a. These shoulders are adapted to engage a downwardly facing shoulder Ila on the swivel ring, formed at the juncture of the open ing 15a and the cylindrical recess therebelow which telescopically receives the cylindrical portion of the shank when the springs are compressed under load.

In this embodiment of the invention, a downwardly depending skirt Ila as provided on the swivel ring l2a, extending downwardly past the shoulder led in the lowermost position of the latter, to substantially close the cylindrical recess in the swivel ring and exclude any foreign matter, such as scale from the surfaces of the springs, which might deposit on the shoulder [8a and interfere with proper full-surface engagement between the shoulders I la and 18a when the springs are fully compressed. A similar skirt may be provided on the swivel ring I2 of Figure 1, extending upwardly between the inner spring l0 and the shank. This skirt may in either case be integral with the swivel ring, as shown, or it may be formed as a separate member with a radially extending flange interposed between the swivel ring and the adjacent ends of the springs to retain the skirt in place.

In Figure 3 the same method of precompressing the springs is employed as shown in Figure 1. A threaded stem 2 la, constituting a reduced extension of the shank 3a, is suitably secured to or formed integral with the lower end of the shank. A nut 29a. is threaded on the stem and exerts thrust against the sleeve member 24a through a bearing 39a to apply initial precompression to the this point.

A swivel locking mechanism 36a similar to the 10 mechanism 36 of Figure 1 is provided for locking the housing 4a against rotation with respect to the swivel ring [2a and the shank 3a. It will be apparent that by inverting all parts of the mechanism 36 of Figures 1 and 6 to 11 except the crank 41, this same mechanism can be used in the book of Figure 3. Hence a detailed description thereof is not deemed necessary. Y

Although there have been described herein two specific embodiments of the invention, it will be understood that the invention is not limited to the detailed construction shown, but is susceptible of various embodiments within the scope of the appended claims.

We claim:

1. In a hook structure, a housing member and a shank member mounted for relative rotary movement, means forming a locking surface associated with said shank member, a locking member pivotally mounted on said housing member and having a locking element movable into and out of engagement with said locking surface, a latch member mounted on said locking member and operable to retain said locking member in one of its positions, and an actuating member mounted for pivotal movement about the axis of said locking member and having a lost-motion connection therewith, said actuating member being operatively connected to said latch member to move the latter into released position during lost motion between said actuating member and said locking member.

2. In a hook structure, a housing member and a shank member mounted for relative rotary movement, means forming a locking surface associated with said shank member, a locking member pivotally mounted on said housing member and having a locking element movable into and out of engagement with said locking surface to releasably lock said housing member and shank member against relative rotation, a pair of latch members mounted on said locking member and operable respectively to latch said locking member in its locking and released positions, and an actuating member pivotally mounted on said housing member and operatively connected to said locking member, said actuating member being also operatively connected to each of said latch members to move the latter into their released positions prior to actuation of said looking member.

3. In a hook structure, a housing member an a shank member mounted for relative rotary movement, means forming a locking surface associated with said shank member, and a unitized locking sub-assembly comprising a frame adapted to be secured to said housing member, a lockingmember journaled in said frame and having a locking element movable into and out of engagement with said locking surface to releasably lock said housing member and shank member against relative rotation, latch means mounted on said locking member and cooperating with saidframe to releasably latch said locking member in its looking or released position, and an actuating member mounted in said frame and operatively connected to said latch means and. said locking member to actuate them sequentially, said locking member, latch means and actu ating member being operatively assembled in said frame prior to attachment of said frame to said housing member.

4. In a hook structure, a housing member and a shank member mounted for relative rotary movement, means forming a locking surface associated with said shank member, means fixed with respect to said housing forming a latch engaging surface, a rotary locking member journa'led within said housing having a locking element movable into and out of engagement with said locking surface to releasably lock said housing member and shank member against relative rotation, latch means pivotally mounted on said locking member releasably engageabl with said latch engaging surface to releasably latch said locking member in looking or released position, a rotary, manually operable actuating member journaled 'within said locking member and operatively connected to said latch means and said locking member to actuate them.

5. In a hook structure, a housing member and a shank member mounted for relative rotary movement, means forming a locking surface associated with said shank member, means fixed with'respect to said housing forming a latch engaging surface, a rotary cylindrical locking memberjournaled within said housing having a looking element movable into and out of engagement with said locking surface to releasably lock said housing member and shank member against relative rotation, latch means pivotally mounted on said locking member releasably engageable with said latch engaging surface to releasably latch said locking member in looking or released position, a rotary, cylindrical, manually operable actuating member telescopically journaled within said locking member and engageable with said latch means and said locking member to actuate them.

6. Ina hook structure, a housing member and a shank member mounted for relative rotary movement, means forming a locking surface associated with said shank member, means fixed with respect to said housing forming a latch engaging surface, a rotary cylindrical locking member journaled within said housing having an exteriorally projecting locking element movable into and out of engagement with said locking surface to releasably lock said housing member and shank member against relative rotation, interiorally extending actuating means for said locking members, latch means pivotally mounted on said locking member including outwardly extending fingers releasably engageable with said latch engaging surface to releasably latch said locking member in looking or released position, and an inwardly extending actuating cam, a rotary, cylindrical, manually operable actuating member telescopically journaled within said locking member and externally extending members engageable with said latch actuating cam and said locking member actuating means to actuate said locking member and said latch means.

7. In a hook structure, a housing member and a shank member mounted for relative rotary movement, means forming a locking surface associated with said shank member, and a unitized locking sub-assembly comprising a frame adapted to be secured to said housing member, a latch engaging surface formed on said frame, a rotary locking member journaled in said frame having a locking element movable into and out of engagement with said locking surface to releasably lock said housing member and shank member against relative rotation, latch means pivotally mounted on said locking element releasably engageable with said latch engaging surface to releasably latch said locking member in its looking or released position, and a rotary, manually operable actuating member journaled Within said locking member and operatively connected to said latch means and said locking member to operate them, said locking member, latch means and actuating member being operatively assembled in said frame prior to attachment of said frame to said housing member.

8. In a hook structure, a housing member and a shank member mounted for relative rotary movement, means forming a locking surface associated with said shank member, and a unitized locking sub-assembly comprising a frame adapted to be secured to said housing member, a latch engaging surface formed on said frame, a cylindrical rotary locking member journaled in said frame having a locking element movable into and out of engagement with said locking surface to releasably lock said housing member and shank member against relative rotation, latch means pivotally mounted on said locking element releasably engageable with said latch engaging surface to releasably latch said locking member in its locking or released position, and a cylindrical, rotary, manually operable actuating member journaled within said locking member and engageable with said latch means and said locking memer to operate them, said locking member, latch means and actuating member being operatively assembled in telescopic relation in said frame prior to att chment of said frame to said housing member.

9. In a hook structure, a housing member and a shank member mounted for relative rotary movement, means forming a locking surface associated with said shank member, and a unitized locking sub-assembly comprising a frame adapted to be secured to said housing member, a latch engaging surface formed on said frame, a cylindrical rotary locking member journaled in said frame having an exteriorally extending locking element movable into and out of engagement with said locking surface to releasably lock said housing member and shank member against relative rotation on an internally extending actuating means, latch means pivotally mounted on said locking element including an outwardly extending latching finger releasably engageable with said latch engaging surface to releasably latch said locking member in its looking or released position, and a cylindrical, rotary, manually operable actuating member journaled within said locking member and having externally extending members engageable with said latch actuating cam and said locking member actuating means to operate them, said locking member, latch means and actuating member being operatively assembled in telescopic relation in said frame prior to gttachment of said frame to said housing mem- 10. A unitized locking mechanism for a hook structure comprising a frame having a latch engaging surface formed thereon, a locking member rotatable in said frame and having a lockmg element, latch means pivotally mounted on said locking member releasably engageable with said latch engaging surface for latching said locking member in locking and released position, and a rotatable, manually operable actuating member journaled within said locking member for actuating said latch means and said locking member, said parts being adapted to be telescopically assembled as a unitized sub-assembly to be secured to a hook structure as an element thereof.

11. A unitized locking mechanism for a hook structure comprising a frame having a latch engaging surface formed thereon, a cylindrical locking member rotatably joumaled in said frame and having a locking element, latch means pivotally mounted on said locking member releasably engageable with said latch engaging surface for latching said locking member in locking and released position, and a cylindrical, rotatable, manually operable actuating member rotatably journaled within said locking member engageable with said latch means and said locking member, said parts being adapted to be telescopically assembled as a cylindrical unitized sub-assembly to be secured within a hook structure as an element thereof.

12. A unitized locking mechanism for a hook structure comprising a frame having a latch engaging surface formed thereon, a cylindrical locking member rotatably journaled in said frame and having an outwardly extending locking element and an inwardly extending actuating means, latch means pivotally mounted on said locking member including an outwardly extending latching finger releasably engageable 14 with said latch engaging surface for latching said locking member in locking and released position and an inwardly extending actuating cam, and a cylindrical, rotatable, manually operable actuating member rotatably journaled within said locking member having outwardly extending members engageable with said latch cam and said locking actuating means, said parts being 7 adapted to be telescopically assembled as a releasably cylindrical unitized sub-assembly to be secured within a hook structure as an element thereof.

RICHARD K. HERTEL. GARTH F. NICOLSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 13,968 Bowles Dec. 18, 1855 541,021 Spitzer June 11, 1895 874,694 Miller Dec. 24, 1907 2,158,232 Gram et al May 16, 1939

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