US2993541A

US2993541A - Subsurface control apparatus

Info

Publication number: US2993541A
Application number: US687406A
Authority: US
Inventors: Martin B Conrad
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1957-10-01
Filing date: 1957-10-01
Publication date: 1961-07-25
Anticipated expiration: 1978-07-25

Description

July 25, 1961 M. B. CONRAD SUBSURFACE CONTROL APPARATUS 2 Sheets-Sheet 1 Filed Oct. 1, 1957 INVENTOR. MAwr/A/ E Cay/e40 zQTTOA/EKSL IIEN:

July 25, 1961 M. B. CONRAD 2,993,541

SUBSURFACE CONTROL APPARATUS Filed Oct. 1, 1957 2 Sheets-Sheet 2 Iii/7111 7-44 5 INVENTOR. 1 f4 1 Mimi/B. fi 0/1/1940 5 BY i 4? M A 4A l Jrran/EKSI United States Patent 2,993,541 SUBSURFACE CONTROL APPARATUS B. Conrad, Downey, Calif., assignor to Baker 011 Tools, Inc., Los Angcles, Calif., a corporation of California Filed Oct. 1, 1957, Ser. No. 687,406 15 Claims. (Cl. 166237) The present invention relates to subsurface well apparatus, and more particularly to well apparatus adapted to gontrol the operation of other devices disposed in a well ore.

An object of the invention is to provide improved subsurface mechanically controlled apparatus for determining the operation of other devices located in a well bore.

Another object of the invention is to provide apparatus for controlling another device in a well bore, the apparatus being adapted to be lowered in the well bore with the other device on a running-in string, and of effecting operation of such other device in response to movement of the running-in string in one longitudinal direction, the apparatus also being adapted to be placed in a condition preventing operation of such other device when the run ning-in string is moved in such direction.

A further object of the invention is to provide apparatus for controlling another device in a Well bore, the apparatus being adapted to be placed in a condition to operate the other device and in a condition for removal from the well bore with the other device without operating the latter. The apparatus can be placed in this latter condition at any time, so long as the device has not been operated.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGS. 1 and 1a together constitute a longitudinal section through apparatus disposed in a well casing, with its parts in condition for lowering the apparatus in the gelcl} casing, FIG. 1a constituting a lower continuation of FIG. 2 is a diagrammatic view in a single plane of the control slot or track and pin or key portion of the apparatus;

FIGS. 3 and 3a together constitute a longitudinal sectron corresponding to FIGS. 1 and 1a, illustrating the apparatus in another operative condition, FIG. 3a constituting a lower continuation of FIG. 3;

FIG. 4 is a cross-section, on an enlarged scale, taken along the line 4-4 on FIG. 3;

FIG. 5 is a fragmentary section, on an enlarged scale, taken along the line of 55 of FIG. 2;

FIG. 6 is a fragmentary section, on an enlarged scale, taken along the line 66 on FIG. 2.

The control apparatus A is disclosed, by way of example in the drawings, as being adapted to operate a gunfiring apparatus B which will institute operation of a fluid pressure device C, such as one adapted to set a bridge plug or corresponding well packer (not shown) in a well casing D. Only a portion of the fluid pressure device is illustrated in the drawings. The remainder of the fluid pressure device and the bridge plug itself is disclosed and described in the patent of Thomas M. Ragan, 2,707,999.

The fluid pressure device C includes a cylinder sleeve 10 threadedly secured to an upper cylinder head 11 to which the lower end of a gun body 12 is threadedly attached. A piston 13 is slidable in the cylinder, being secured to the upper end of the piston rod 14. The piston and the cylinder device together can efiect setting of the bridge plug (not shown) in a manner described in the aforesaid patent. The cylinder head 11 has a central passage 15 therethrough to form a combustion chamber in which a power charge 16, such as a fusee or an appropriate propellant, may be disposed. Combustion of this power charge 16 is initiated by firing a blank cartridge 17 mounted in the upper end of a gun barrel 18 disposed in the upper portion of the cylinder head 11 and threadedly secured to the lower end of the gun body 12. The cartridge 17 may be retained in position within the gun barrel by a cap 19 threaded on the upper end of the gun barrel 18, this cap 19 bearing against a thin, metallic disc 20, in turn, bears against the upper end of the cartridge 17.

The cartridge 1'7 is fired by a firing pin 21 slidably mounted in a central bore 22 in the gun body 12. A helical compression spring 23 is disposed around the firing pin, its upper end bearing against a spring seat 24 in the gun body and its lower end against a flange 25 on the firing pin. The firing pin has a point 26 initially spaced above the disc 20 and cartridge 17 When the spring 23 is allowed to expand, it will drive the point 26 downwardly through an opening 27 in the cap 19 against the disc 20, the striking force being transmitted to this cartridge 17 to effect its firing. The flame emanating from the cartridge will ignite the upper end of the power charge or propellant 16 which will then burn to generate a gas under pressure capable of moving the piston 13 downwardly in the

cylinder

10, 11, or, reactively, the cylinder upwardly with respect to the piston.

The firing pin 21 is held initially in an ineffective position against the compressive force of the spring 23 by one or a plurality of latch levers 28 mounted in a transverse slot 29 in the gun body 12. The levers are opposed to one another, each lever being pivotally mounted on a fulcrum pin 30 secured to the gun body and having downwardly extending legs 31 which diverge from one another and project laterally outwardly to some extent beyond the periphery of the gun body 12. The upper part of each latch lever 28 is constituted as an arm 32 having a finger 33 adapted to be received within a firing pin groove 34 and under a firing pin shoulder 35, to prevent downward propulsion of the firing pin 21 under the influence of the compression spring 23. A tension spring 36 is secured to the upper ends of the arms 32 to urge them and the fingers 33 inwardly with respect to one another, and hold the fingers under the shoulder 35.

The control apparatus A is secured to the gun body, the upper end of which is threaded into a connector sub 37 threadedly secured to the lower end of an elongate control member 38. The upper end of this control member is threadedly secured to a rope socket or a sinker bar device 39 to which the lower end of a wire line E, or other running-in string, is suitably attached. The wire line extends to the top of the well bore and is the means by which the apparatus is lowered in the well casing D and also removed therefrom.

A tripping sleeve 40 surrounds the control member 38 and is movable longitudinally relative thereto. When the control member 38 moves upwardly relative to the tripping sleeve 40, it will move the gun body 12 and the mechanism secured thereto upwardly with it until the legs 31 of the levers 28 are moved upwardly within the lower end of the tripping sleeve 40, which will shift the legs 31 inwardly and the arms 32 and fingers 33 outwardly, releasing the fingers from the firing pin shoulder 35, thereby permitting the compression spring 23 to expand and propel the firing pin 21 and its point 26 down- 3 wardly against the disc and cartridge 17 to fire the latter. The ability of the trip sleeve 40 to move downwardly relative to the control member 38 and the gun firing apparatus is determined by a pin and

slot interconnection

41, 42 between the trip sleeve and the control member.

The upper portion of the tripping sleeve 40 is formed with circumferentially spaced, longitudinal extending slots 43, each of such slots receiving a drag block 44. Each drag block is urged outwardly into frictional engagement with the wall of the well casing D by one or a plurality of helical compression springs 45 bearing against the base of each slot 43 and also bearing against the end of a. spring receiving socket 46 formed in each block. Downward movement of the blocks '44 relative to the tripping sleeve 40 is prevented by a retaining ring 47 encircling the tripping sleeve and disposed in grooves 48 formed in the blocks. The lower end of the ring 47 is adapted to engage an upwardly facing shoulder 49 on the tripping sleeve, to prevent the drag blocks firorn moving downwardly in the tripping sleeve. Upward movement of the blocks 44 relative to the tripping sleeve 40 is prevented by their engaging the lower end of a housing and guide 50 slidably mounted on the control member 38. In fact, the housing and guide 50 is firmly secured to the tripping glieeve 40 by a plurality of longitudinally extending screws Outward movement of the drag blocks 44 under the influence of the springs 45 is limited by their engagement with the retaining ring 47 and also with another retaining ring or sleeve 52 encircling the housing 50 and secured thereto by a screw 53. This latter retaining ring 52 also serves as a closure member for a radial slot 54 formed through the housing and guide 50 in which the key or pin 41 is mounted, this key or pin being received within the track or slot 42 formed in the control member 38. Since the key or pin 41 is to partake of slight radial movement in the housing and guide 50, the outer end of the key is spaced from the inner wall of the retaining ring 52, the key being urged in an inward direction against the bottom of the track or slot 42 by a helical compression spring 55, the outer end of which engages the ring 52 and the inner end of which engages the base of a key socket 56 in which the spring is primarily disposed.

During lowering of the apparatus in the well casing, the friction drag blocks 44 slide frictionally against the wall of the well casing and tend to retain the tripping sleeve 40 in an upward position along the control member 38, the lower end of the tripping sleeve then being spaced a substantial distance above the latch levers 28. When in this position, the key 41 is disposed in the upper end 59 of a longitudinally extending running-in portion 60 of the slot, engagement of the control member 38 at the upper end of the slot with the key 41 forcing the drag device 40-56 downwardly with the control member 38 and all of the other apparatus in the well casing. The track or slot 42 is so designed that the drag device can trip the latch levers 28 upon elevation of the running-in string E and the control member 38 to the proper extent. On the other hand, should it be desired to remove the entire apparatus from the well casing without tripping the levers 28, the slot or track 42 is so designed as to prevent suflicient relative downward movement of the tripping sleeve 40 along the control member 38 to occur to trip the latch levers. In fact, the slotted structure is so devised that at any time prior to actual tripping of the latch levers 28 by the lower end of the tripping sleeve 40', the apparatus can be conditioned to couple the tripping sleeve 40 to the control member 38 and prevent its relative downward movement to release the latch levers 28 from the firing pin 21 Despite the placing of the apparatus in the last-mentioned condition, the key and

slot device

41, 42 can be suitably manipulated to again place the apparatus in a condition to release the latch levers 28. The apparatus can be placed in a condition for operating the lower well device or to preclude operation ofi 4 such lower well device at any time under the full control of the operator at the top of the well bore, and as many times as is required, all through a simple, straight line raising or lowering of the running-in string E and the apparatus secured thereto.

The slot 42 provided in the exterior of the control member 38 is represented diagrammatically in FIG. 2. It includes the upper longitudinal extending running-in portion 60- having a closed upper end, the lower end 61 of which merges into an inclined slot portion 62, which, in turn, merges into a pulling-up portion 63 in which the pin 41 is to be disposed in the event the apparatus is to be removed from the well bore or casing without effecting tripping of the latch levers 28. The pulling-up slot portion 63 is disposed arcuately to one side and to the right of the running-in portion 60. The upper end 64 of the pulling-up portion'merges into another tapered slot portion 65 inclined to the right, which, in turn, merges into a longitudinally extending recycling portion 66 arcuately displaced from the pulling-up portion 63. The upper end of this recycling portion 66 merges into an inclined slot portion 67 that communicates at its upper end with the running-in portion 60 near the upper part of the latter. Thus, the pin or key 41 can move relatively from the running-in position (position 1 in FIG. 2) at the upper end of the slot 60 downwardly to the inclined slot portion 62, thence downwardly into the pulling-up portion 63 and to the lower end 68 of the latter (position 2), which is closed. From the closed bottom 68 of the pulling-up portion 63 the pin '41 can move upwardly therewithin to the tapered track portion 65 and into the recycling portion 66, thence moving upwardly through the inclined slot portion 67 back to the running-in portion 60. The traversing of the key or pin 41 through the track portions, as described above, can take place merely by appropriate raising and lowering the running-in string E and the control member 38, the pin 41, of course, remaining relatively in a. fixed position within the casing by virtue of the frictional engagement of the drag blocks 44. against the wall of the well casing D.

On the other hand, should it be desired to trip the lower well device B, as by tripping the latch levers 28, the pin 41 is located in the recycling portion 66 and can then move downwardly in such recycling portion to a lower tapered slot portion 70 which is inclined in a downward direction towards the left, this tapered slot portion merging into a firing or actuating slot portion 71, which depend therefrom to a certain extent. The upper end 72 of the longitudinal firing or actuating portion 71 merges into another recycling portion 73 which is inclined in an upward direction towards the left (as seen in FIG. 2), this inclined portion including an intermediate slot portion 74 which exits into an upper slot portion 75 inclined in an upward direction toward the running-in portion 68. When the pin 41 is in either

recycling portion

66 or 73, it can bemoved relatively in a downward direction within the slot 42, as by moving the control member 38 upwardly to place the pin 41' in the firing or actuating portion 71. If the control member 38 is moved upwardly sufiiciently, the pin 41 can move toward the lower end 77 (which is closed) of the firing slot portion 71, so that the lower end of the'trip sleeve 40 can engage the latch lever legs 31 and release the fingers 33 from the firing pin 21.

The pin 41 can move relatively in the slot 42 from the pulling-up portion 63 into the recycling portion 66 then downwardly to the firing portion 71 and then upwardly through the left-hand recycling portion 73 back into the running-in portion 60, from where the pin 41 can again move either upwardly to the upper end 59 of the runningin portion or downwardly back into the pulling-up slot portion 63. However, the pin 41 cannot move from the upper end 59 of the running-in portion 60 into the recycling portion 66, from the running-in portion 68 into the left recycling portion 73, from the firing or actuating portion 71 back to the right'recycling portion 66, from the pulling-up portion 63 back into the running-in portion 60,

a or from the right recycling portion 66 back to the pullingup portion 63. This action is precluded by forming guide shoulders between many of the tapered slot portions and the longitudinally extending portions with which they communicate. A longitudinally extending shoulder 80 is provided near the upper end of the running-in portion 60 and the inclined recycling portion 67 by making the running-in portion adjacent the inclined portion 67 deeper than the adjacent inclined portion. This shoulder 80 is perhaps shown most clearly in FIG. 5. Similarly, the right hand recycling portion 66 along the inclined slot portion 65 leading from the pulling-up portion 63 is also made deeper than the adjacent inclined slot portion 65 to provide a shoulder 81 along which the key 41 will slide, the key being urged down to the bottom or base of the slot by the spring 55, and being prevented from moving back into the pulling-up portion 63. Similarly, the firing or actuator portion 71 is made deeper than the adjacent inclined slot portion 70 to provide a shoulder 82 preventing return movement of the pin 41 from the firing or actuating portion 71 back into the right recycling portion 66. Such shoulder is shown most clearly in FIG. 6. The running-in portion 60 adjacent the left recycling slot portion 75 is also made slightly deeper than the latter to provide a guide shoulder 83, and the pulling-up portion 63 is made slightly deeper than the adjacent inclined slot portion 62 to provide a guide shoulder 84 to the left thereof.

Actually, the shoulder 80 can be formed as by tapering the base of the upper recycling inclined slot portion 67 from the longitudinal section of such recycling portion to a slight extent in an outward direction toward the runningin portion 60. Similarly, the base of the inclined portion 65 at the upper end of the pulling-up portion 63 can be tapered from the latter to a slight extent in a laterally outward direction to form the shoulder 81. The same is true of the lower inclined right recycling portion 70, the base of which is tapered from the longitudinal part of such portion laterally outward toward the actuating portion 71 to form the guide shoulder 82. .The upper part of the left recycling portion 75 has its base tapered from the firing or actuating portion 71 laterally outwardly to a slight extent to define the guide shoulder 83 with the lower part of the running-in portion 60, whereas the base of the inclined groove 62 at the lower end of the running-in portion is tapered in a downward direction laterally outward to a slight extent to form the guide shoulder 84 at the left side of the pulling-up slot portion 63.

In the operation of the apparatus heretofore described, it is run in the well casing with the parts occupying their relative positions disclosed in FIGS. 1 and la. The fingers 33 of the latch levers 28 are disposed under the shoulder 35 to hold the firing pin 21 in its upper position against the expansive force of the spring 23. In view of the friction of the drag blocks 44 against the wall of the well casing D, the tripping sleeve 40 is disposed in its uppermost position along the control member 38, as determined by engagement of the key or pin 41 with the upper end 59 of the running-in slot portion 60 (position 1 in FIG. 2). The apparatus is lowered in the well casing until the levers 28 are to be released from the firing pin 21. When the firing pin is to be released, the running-in string or wire line E is elevated, wlu'ch will raise all of the apparatus with the exception of the tripping sleeve 40, drag mechanism 44, etc. and the key or pin 41. The pin 41 will move from the No. 1 position shown in FIG. 2, which is the running-in position, relatively downward within the slot 60, shifting into the inclined slot portion 62 and then into the pulling-up portion 63 (No. 2 position). A continuation of the upper movement of the running-in string E and the control member 38 will pull the entire drag device upwardly with it. This condition of the parts would be retained if the apparatus is to be elevated in the well casing. However, if the firing pin 21 is to be released, then the running-in string E and the control member 38 are again lowered, to cause the pin 41 to move relatively upwardly in the pulling-up slot portion 63, through the inclined slot portion 65 and into the right hand recycling slot portion 66, such as to the No. 3 position shown in FIG. 2. Thereafter, if the firing pin is to be released, the running-in string E and the control member 38 are again elevated, the drag blocks 44 preventing the pin 41 from moving upwardly with the control member 38, the pin moving relatively downward in the recycling slot portion 66, through the lower tapered portion and into the firing or actuating slot portion 71. If the running-in string E and control member 38 are elevated sutficiently to place the pin 41 in the No. 4 position shown in FIG. 2, then the trip sleeve 40 will engage the latch lever legs 31 to release the firing pin 21 and allow its point 26 to fire the blank cartridge 17, which will effect ignition of the power charge 16, its combustion and the performance of the desired function in the Well bore through use of the cylinder and piston apparatus 10, 13. As described in the aforesaid Patent 2,707,999, after the operation has been performed the cylinder and piston apparatus is automatically released and the entire apparatus can then be elevated in the well casing D and removed therefrom.

Despite the fact that the pin may be in the firing or actuating portion 71 of the slot 42, so long as the trip sleeve 40 has not actually released the latch levers 28 from the firing pin 21, the apparatus can still be removed from the well casing without releasing said latch levers. Assuming the key or pin 41 to be disposed in the firing or actuating portion 71 of the apparatus, it is only necessary to lower the wire line E and the control member 38, which will effect relative upward movement of the pin 41 through the left hand

recycling slot portion

73, 74, 75 and back into the running-in portion 60 of the apparatus. After the pin 41 has been disposed in such running-in portion 60, elevation of the wire line B will elevate the control member 38 and place the pin 41 back in the No. 2 position shown in FIG. 2, whereupon the entire apparatus can be elevated without releasing the latch levers 28, the tripping sleeve 40 and drag device 44, etc. then being coupled to the control member 38.

Assuming the pin 41 to be disposed in the No. 3 position shown in FIG. 2, it can be returned to the pullingup position, which is the No. 2 position shown in FIG. 2, merely by lowering the running-in string E and the control member 38, which will effect a relative upward movement of the pin or key 41 through the inclined slot portion 67 back into the running-in portion 60, whereupon upward movement on the running-in string E and control member 38 'will effect a relocation of the pin 41 in the lower end or bottom of the pulling-up slot portion 63 (No. 2 position).

Because of the various guide shoulders 81 to 84 provided in the slot structure, the pin 41 is caused to follow the different paths designated by arrows on FIG. 2 of the drawings and described above. The pin 41 cannot move from the running-in slot portion 60 into the right hand recycling portion 66, since the upper shoulder prevents that action from occurring. Similarly, the pin 41 cannot move from the running-in slot portion 60 into the left hand recycling portion 75 because of the shoulder 83. The pin cannot move from the pulling-up slot portion 63 back into the running-in portion 60 because of the guide shoulder 84, and it cannot move from the right hand recycling portion 66 back into the pulling-up portion 63 because of the presence of the guide shoulder 81. Finally, the pin 41 cannot move from the firing or actuating portion 71 back into the right hand recycling portion 66 because of the presence of the guide shoulder 82. Because of the presence of the various shoulders precluding movement of the pin 41 in certain directions within the various portions of the slot structure 42, the pin cannot inadvertently move to any undesired positions. The operator at the top of the Well bore, by the extent of raising and lowering of the running-in string E and the control mern- 7 ber=38 attached thereto, can effect a positioning of the key or pin 41 in any slot portion he desires.

The inventor claims:

1. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion at one end thereof, a longitudinally extending actuating portion at the opposite end thereof, a pulling-up portion communicating with the running-in portion and terminating longitudinally to one side of said actuating portion, and an interconnecting portion extending between said pulling-up portion and said actuating portion.

2. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuatng portion spaced longitudinally from said runningin portion, a pulling-up portion intermediate said runningin and actuating portions and communicating with said running-in portion, one end of said pulling-up portion being closed longitudinally to one side of said actuating portion, and an interconnecting portion extending from the other end of said pulling-up portion to said actuating portion.

3. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion spaced longitudinally from said runningin portion, a pulling-up portion intermediate said runningin and actuating portions and communicating with said running-in portion, said pulling-up portion being laterally offset from said running-in portion, one end of said pulling up portion being closed longitudinally to one side of said actuating portion, and an interconnecting portion extending from the other end of said pulling-up portion to said actuating portion and laterally offset from said pulling-up and actuating portions.

4. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion spaced long tudinally from said runningin portion, a pulling-up portion intermediate said runningin and actuating portions and communicating with said running-in portion at one of its ends, one end of said pulling-up portion being closed longitudinally to one side of said actuating portion, an interconnecting portion extending from the other end of said pulling-up portion to said actuating portion and to the other end of said running-in portion.

5. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion spaced longitudinally from said runningin portion, a pulling-up portion intermediate said runningin and actuating portions and communicating with said running-in portion, one end of said pulling-up portion being closed longitudinally to one side of said actuating portion, an interconnecting portion extending from the other end of said pulling-up portion to said actuating portion, and an interconnecting portion extending from said actuating portion to said running-in portion.

6. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion spaced longitudinally from said runningin portion, a pulling-up portion intermediate said runningin and actuating portions and communicating with said running-in portion, said pulling-up portion being laterally offset from said running-in portion, one end of said pulling up portion being closed longitudinally to one side of said actuating portion, an interconnecting portion extending from the other end of said pulling-up portion to said actuating portion and laterally offset from said pulling-up and actuating portions, and an interconnecting portion extending from said actuating portion to said running in portion.

7. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion spaced longitudinally from said runningin portion, a pulling-up portion intermediate said runningin and actuating portions and communicating with said running-in portion, said pulling-up portion being laterally offset from said running-in portion, one end of said pulling-up portion being closed longitudinally to one side of said actuating portion, an interconnecting portion extending from the other end of said pulling-up portion to said actuating portion and laterally offset from said pullingup and actuating portions, and an interconnecting portion extending from said actuating portion to said running-in portion, said pulling-up portion being laterally ofiset from said running-in portion, and said interconnecting portions being laterally offset from said running-in and actuating portions.

8. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion spaced longitudinally from said runningin portion, a pulling-up portion to one side of said actuating portion and communicating with said running-in portion, an interconnecting portion extending between said pulling-up portion and said actuating portion, and means for preventing direct return movement of said pin from said pulling-up portion to said running-in portion.

9. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion spaced longitudinally from said running-in portion, a pulling-up portion intermediate said running-in and actuating portions and communicating with said running-in portion, one end of said pulling-up portion being closed longitudinally to one side of said actuating portion, an interconnecting portion extending from the other end of said pulling-up portion to said actuating portion, and means for preventing direct return movement of said pin from said pulling-up portion to said runningin portion and from said actuating portion to said interconnecting portion.

10. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion spaced longitudinally from said running-in portion, a pulling-up portion intermediate said running-in and actuating portions and communicating with said running-in portion, said pulling-up portion being laterally ofiset from said running-in portion, one end of said pulling-up portion being closed longitudinally to one side of said actuating portion, a

first interconnecting portion extending from the other end of the said pulling-up portion to said actuating portion and laterally ofiset from said pulling-up and actuating portions, a second interconnecting portion extending from said actuating portion to said running-in portion, and means for preventing direct return movement of said pin from said pulling-up portion to said running-in portion, from said first interconnecting portion to said pulling-up portion, from said actuating portion to said first interconnecting portion, from said running-in portion to said first interconnecting portion, and from said running-in portion to said second interconnecting portion.

11. In apparatus of the character described: a first member having a coupling pin; a second member movable relative to said first member and having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion spaced longitudinally from said running-in portion, a pulling-up portion to one side of said actuating portion and communicating with said running-in portion, and an interconnecting portion extending between said pulling-up portion and said actuating portion, said pulling-up portion being deeper at its region of communication with the running-in portion than the adjacent running-in portion to provide a 'shoulder engageable with said pin to prevent direct return movement of said pin from said pulling-up portion to said running-in portion.

12. In apparatus of the character described: an outer member having a coupling pin; an inner member Within and movable longitudinally relative to said outer member; said inner member having a slot in which said pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion below said running-in portion, a pulling-up portion intermediate said running-in and actuating portions and communicating with said running-in portion, the lower end of said pulling-up portion being closed above said actuating portion, and an interconnecting portion extending from the upper end of said pullingup portion downwardly to said actuating portion.

13. In apparatus of the character described: an outer member having a coupling pin; an inner member within and movable longitudinally relative to said outer member; said inner member having a slot in which a pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion below said runningin portion, a pulling-up portion intermediate said running-in and actuating portions and communicating with said running-in portion,

the lower end of said pulling-up portion being closed above said actuating portion, and an interconnecting portion extending from the upper end of said pulling-up portion downwardly to said actuating portion, said interconnecting portion also extending from the upper end of said pulling-up portion upwardly to said running-in portion.

14. In apparatus of the character described: an outer member having a coupling pin; an inner member within and movable longitudinally relative to said outer member; said inner member having a slot in which a pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion below said running-in portion, a pulling-up portion intermediate said running-in and actuating portions and communicating with said running-in portion, the lower end of said pulling-up portion being closed above said actuating portion, a first interconnecting portion extending from the upper end of said pulling-up portion downwardly to said actuating portion, and a second interconnecting portion extending upwardly from said actuating portion to said running-in portion.

15. In apparatus of the character described: an outer member having a coupling pin; an inner member within and movable longitudinally relative to said outer member; said inner member having a slot in which a pin is positioned, said slot including a longitudinally extending running-in portion, a longitudinally extending actuating portion below said running-in portion, a pulling-up portion intermediate said running-in and actuating portions and communicating with said running-in portion, the lower end of said pulling-up portion being closed above said actuating portion, a first interconnecting portion extending from the upper end of said pulling-up portion downwardly to said actuating portion, said first interconnecting portion also extending from the upper end of said pulling-up portion upwardly to said runningin portion, and a second interconnecting portion extending from said actuating portion upwardly to said runningin portion.

References Cited in the file of this patent UNITED STATES PATENTS 2,389,869 Phipps Nov. 27, 1945 2,690,228 Baker Sept. 28, 1954 2,707,999 Ragan May 10, 1955 2,720,921 Brown Oct. 18, 1955