US1570812A

US1570812A - Latch guard for casing-handling tools

Info

Publication number: US1570812A
Application number: US672103A
Authority: US
Inventors: Elihu C Wilson
Original assignee: Individual
Current assignee: Individual
Priority date: 1923-11-01
Filing date: 1923-11-01
Publication date: 1926-01-26
Anticipated expiration: 1943-01-26

Description

Patented 26,1926. d

.UNITED STATES PATENT OFFICE.

EELIHU.l C. WILSON, Fv LOS ANGELES, CALIFORNIA.

LATCH GUAB) FOB GASING-HANDLTNG TOOLS."

Application iled Novemberl, 1923. Serial No. 672,108.

To all 'wholmz't may cncern.'

Beit known that I, ELIHH C. WILSON, a"

i citizen of the United States, residing at Los Angeles, inthe county of Los Angeles and lState of California,have invented new and usefulv Improvementsin- Latch Guards for Casing-Handling Tools, of which the following is a detailed specification. l'

This invention relates to latch guards for casing handling tools and has for, its lrimary object to provide means for guar ing latches against-accidental unlocking by the action4 of extraneous bodies, such as cables pr rigging .customarily suspended in proximity with this class of tools.'

While my device is for use in connection with vany clamping tool having a certain general typeV of latch incorporated 'there- -A with, such as will be noted later, I have chosen to illustrate myinventionin connection with a' casing elevator and latch of the type disclosed in -my copending application on well elevators, led April th, 1920,

Serial Number 375,332. Bythus illustrat ing a practical embodiment of myinventi'on witha definite structure, I may better point out its function and value, but the4 accompanying illustrations and `following descrlption are not in any way to be considered as limitations of the invention. The casing elevator disclosed in aforementioned oopending application, and here 1llustrated in part, is forthe purpose of setting vided for locking and withdrawing well casings or drill pipe, and mainly consists oftwo relatively movable clamping members adapted to be swung linto and out of casing encircling position and shifted vertically along the casing into bearing with annular shoulders formed 'byV casing collars.

A spring urged, oscillatory latch 1s prothe two members together, and of necessity, as will be later apparent,

the free end of the latch has a clearance from the immediately adjacent portions'ofy the outer peripheral face of one of the clamping members and the nose of the latch ,is beveled to aid it in riding over certain locking lugs during the closing of the elevator. An opening 1s thus left between the periphery of the clamping member and the end of the latch, thisopening inviting the accidental entrance of cables or the like between olamp vmember` and latch, which enbottom, and the ampleroom for the insertion of the-operators hand or suitable tools for purposely and wllfully oscillating the-latch to unlock the elevator.v

The construction and arrangement of my' deyice will be more fully set forth in the fol'-` low'lng .detalle-d description, in which further obJects and features -of novelty of the latch to protectit top and f space between guards leaves n and drop the `work with theliability of is? l invention will .be,stated. Reference will be i had to the,4 accompanying drawings, in which; Fig. 1 is a'perspective view showing my latch guard incorporated with a casing elevator, the latter vbeing in unlocked and opened position; and

Fig. 2 is av view similar tovFig. 1, but showing the elevatorclosed and'locked. l I will first briefly describe the structure of the-elevator, proper, but will not attempt to assign definite reasons for certain` of the latch elements being shaped and arranged as they are, for :these points are fully discussed `in my aforementioned copending applica'- tion and have no direct bearing on the present invention.v It will sullice to state that.

the latch elements are designed to coact iii a manner to resist accidental unlocking during vertical movement of the casing and casing elevator, either from verticalvibrations of the well pipe or from stresses and strains which may be put on the elevator during operation. Y

A gate A 'is hinged by vertical pin 10 to body member B, the outer end of the gate being free to swing to open and close the elevator. Gate A and body B maybe considered as complementary clamping and holding members defining a bore for the re- -ception of a casing or drill pipe, and suspension \links (not shown) are adapted to be passed @through openings 11 in bifurcated body extensions 12, whereby the elevator may be disposed over the mouth of a well and raised or lowered by the usual hook and tackle in the derrick or rig.

A. T-shaped oscillatory latch 13, havin a shank 14 and a transverse head 15, is rigi with vertical pivot shaft 16, the latter belng journaled in knuckles 16" on body member B. Latch 1'3 is adapted to be urged or biased in acounter-clockwise direction, as viewed in the figures, by spring 17, and stop means (not shown) are provided in connection with the body member B to rlimit latch movement in this direction in order that the latch may not be swung towards the elevator bore sufficiently to interfere with the closing of the elevator. s i

The longitudinal side face 18 of head 15 forms the nose of the latch and is beveled olf so the head will automatically be swung outwardly, as the gate is being closed, by engagement with the curved forward face 19 of vvertically spaced locking lugs 20 on gate A. When the gate is fully closed, spring 17 biases latch 13 through an arcuate path into the position of Fig. 2te lock the elevator, the latch shank 14 then lying between lugs 20 and the locking faces 21 of head 15l seating against lug shoulders 22. Preferably,

the locking faces 21 are arcuate and concentric with the latch axis, and shoulders 22 are arcuate and concentric with said axis when gate A isclosed.

When in lockingposition there is neces-` sarily a space between nose 18and the adjacent surface of gate A, and'but for my guard means, ropes, cable rigging or other bodies extraneous to the elevator, are liable to work their way or be accidentally pulled between head 15 and gate A, with the result of oscillating the latch out 0f locking engagement and allowing'the elevator to swinU open. The .points of engagement between the gate and the ends of the latch head are, of course, mostexposed to the entrance of extraneous bodies, and have therefore provided means for particularly protecting these points. Accidental unlocking ofthe elevator is apt t0 be most disastrous, both to operators and work, and I therefore consider my improve ment to be of great value both fromv a safety and economic standpoint.

I provide guard lugs 23 which extend laterally ,from gate A and are preferably, though not necessarily, integral wit-h'lugs 20, there being a guard lug coextensive with each locking lug. When in locking posit1on, the inner lateral face 24 of head 15 is adapted to bear against shoulders 25 of guard lugs 23, these lugs extending suiiiciently from the peripheral face of gate .A to bring shoulders 25 well be ond the sai'd peripheral face, so head 15, w en in the pop.

1,57o,s1a y sition of Fig. 2, is spaced an appreciable distance from the elevator body to facilitate the insertionof an operators hand or a suitable tool'between gate and latch when wilful unlockin is -to be accomplished. The vertical spacing of lugs 23 gives vertical clearance for' the hand or tool in purposely unlockingv the 4 elevator.

Now it will be observed that shoulders, 25 on the upper and lower guard lugs extend above and below the upper and lower epds of head 15, and that ends 26 of the guardlugs extend beyond and partially around the beveled end or latch nose 18. AThe hdrizontal outline of shoulders 25 may be considered as complementary to said face 24 and, to a limited extent, of latch nose 18. *i

By reason of the above characteristics, guard lugs 23 protect both end and side pointsy of engagement between latch head and gate in a manner to guide extraneous bodies awayfrom these points of engagement and to prevent `the entrance of such bodies between the engaged members. Furthermore, the rearwardly inclined or curved faces 27 extending from the peripheral face of the gate to lug ends 26, serve to guide cables and the like away from and over the points of latch engagement to further minimize the chance of accidental unlocking action. l

In the drawings, shoulders 25 are shown as serving to limit the counterclockwise or latching movement of the latch when the gate is closed, and may therefore perform the auxiliary function of a stop, but it will be understood, it lies within the scope of my invention to limit such movement by other means, and that the guard lugs will function as such without the existence of a full or evenpartial bearing between head 15 and shoulder 25. The important characteristics are that shoulders 25 extend vertically beyond the ends of the latch'head; that the i ends of the guard lugs extend in amanner to prevent the entrance of bodies between the latch nose and gate body, andthat the inclined faces of the lugs are formed and arranged to guide cables, or the like, which may strike the peripheral face of the gate, around and over the latch nose.

I may, of course, provide the guard lugs in greater number than that shown or provide a single lug extending vertically from4 the top of upper shoulder 25 to the'bottom of lower shoulder 25, but `such provision would cause the partial or total closing of the clearance space between latch and gate,

and thus render it more difficult to manually unlock the elevator. Y

Finally,'I wish to repeat the reservation that the illustrations and description are to be considered merely as illustrative and not as restrictive on the broader claims'appended hereto, for it'will be understood that valao i including a shank, a head on the free end of the shank and with its outer longitudinal face forming the nose of the latch, the member with which said latch is engaged being provided with spaced locking lugs with which said headv is adapted to engage and between which the shank thereof is received, spaced guard lugs on -the [latch engaged clamp member, shoulders on said guard lu s and adapted to be engaged by the inner si e face of the latch when in locking position, said shoulders extending longitudinally beyond the ends of the head, and the ends of the guard lugs extending partiallyaround the nose of the latch.

2. In casing handling tools, the combination of a plurality of clamping and holding members hinged together and adapted to embrace between them a pipe or casing, Van,

oscillatory latch device pivotally connected with one of said members, `said latch device including a shank, a head on the free end of the shank and with its outer longitudinal face beveled and forming the nose of the latch, the member with which said'latch is engaged bein provided with spaced locking lugs with w ich said head is adapted to engage and between which the shank thereof is received, spaced guard lugs on the latch engaged clamp member, shoulders on said guard lugs and adapted to be engaged by` the inner side face of the latch when in locking position, said shoulders extending longitudinally beyond the ends of the head, and the shoulder faces of the guard lugs being curved complementary to the bevel of the latch nose and extending laterally partially around the nose.

3. In casing handlin tools, the combination of a plurality of 'cIamping and holding members hinged together and adapted to embrace between them a pipe or casing, an oscillatory latch devicepivotally connected with one of said members, said latch device including a shank, va head on the free end of the shank and with its outer longitudinal face iorming the nose of the latch, the member with which said latch is engaged being provided with spaced locking lugs withv which said head is adapted to engage' and between which the shank thereof is received,

spaced guard lugs lon the latch engaged clamp member, shoulders on said guard lugs and adapted to be engaged by the inner side face of the latch when in locking position,

said shoulders extending longitudinally beyond the ends of lthe head, the ends of the guard lugs extendingpartially around the nose of the latch, and theguard lugs being provided with inclined guard faces extending from the body of the latch engaged clamp member to theends of the guard lugs.

4. In casing handling tools, the combination ot a plurality of clamping and holding members hinged together and adapted to embrace between thema pipe or casing, an oscillatory latch device pivotally connected with one of said members, said latch device including a shank, a head on the free end ot the shank and with `its outer longitudinal facel forming the nose of the latch, the member with which said latch is engaged being provided with spaced locking lugs with which said head is adapted to engage and between which the shank thereof is received, spaced guard lugs on the latch engagea clamp member and integral with the locking lugs, shoulders on said guard lugs and adapted to be engaged by the inner side face of the latch when in locking position', said Vshoulders fextending longitudinally beyond the ends of the head, and the ends of the guard lugs extending partially around the nose of the latch.

v 5. In casing handling tools, the combina'- tion of a plurality of clamping and holding members hinged together and adapted to embrace'between them av pipe or casing, an oscillatory latch device pivotally' connected with onehof the members, the latch device including a shank, a latch and handle head on the free end of the shank with its outer Ilongitudinal face forming the nose of the latch, the member with which said latchis engaged having a locking lug engageable by said head, and having stop means to limit the movement of the head toward said' mem- ELIHU o. WILSON.