US1803721A - Hoisting clevis - Google Patents

Description

B. S. MINOR HOISTING CLEVIS May 5, 1931.

Filed Dec. 1, 192

,- fi' S M 1. 7101:

Patented May 5, 19 31 YUNITED S AT rum s. MINOR, 01* SAN PEDRO, CALIFORNI PATENT OFFICE 5 V riorsrme cLnvIs Application filed'Dcember 1,1928. Serial No. 323,1 84. V

This invention relates to a hoisting clevis of the W8ll 'kI1OWl'l VVigle type for use in connection with the drilling of oil wells.

The Wigle hook as shown in the re- 5 issued U. S. Patent No." 14,258, ISSUGdJELIl1lary 23,1917, has been adopted as standard equipment for a long term of years, and moreover has generally proven entirely satisfactory with the exception that open mouthed hooks are subjected to excessive strains ,when raising or lowering long strings of casing and tubing in Wells, such undue strains oftentimes causing a hook failure. Further if the safety latch for the hook is not closed the load frequently be- 7 comes disengaged therefrom causing serious accidents, and lastly the single spring ne'ces-' sitated by the Wigle structure has proven inadequate for supporting the immense loads carried by the hook.

In the present invention all the above recited disadvantages are largely overcome, the hook in the Wigle construction being replaced by a closed yoke for engaging the load and thus preventing an accidental disengagement therefrom. Further as pro?" vision is made for employing a plurality of springs of sufiicient strength to carry large loads all danger of mutilation of the tubing threads when screwing or unscrewing casing.

is eliminated.

It is therefore a chief object of the invention to provide a hoisting clevis construction that will eliminate all danger of accidental disengagement of the load carried thereby.

A further object is to provide a device having adequate resilient support for the load carried thereby and thus eliminate the strain and wear onthe casing threads when connecting and disconnecting the casing strings.

In the drawings wherein a single embodiment of the invention is shown by way of illustration r r Fig. 1, is a front elevation of the hoisting clevis with parts broken away to more clearly disclose the construction. Fig. 2, is a side elevation of the same. In the drawings, 5 designates the hoisting clevis as a whole that preferably consists of a downwardly extending shank member 6, its upper end being bifurcated andpivotally engaging the lower transverse pin. 7 of a travelling sheave block 8 of the usual well known form. Loosely mounted on the shank member is a pair of cross bars 9 and 10, bar 9 resting on the upper part 11 of an anti-friction bearing .12, whose lower part 13 in turn is carried by the flangeof a-cap nut 14 secured to the threaded end of the shank member. The outer end of both bars are provided with bores through which pass the arms 15, 16, of a yoke 17 ,the head of the yoke extending below the cap nut in order that it may be freely engagedby the upper arms or bails of a casing elevator (not shown).

Mounted onthe-arms of the yoke and between the bars are coil compression springs 18, 19, that are intended to resiliently support the load, such as astring of casing, when the same is attached to the yoke, the spring function being exactly the same as in the NVigleconstruction.

Loosely mounted on the shank member 6 and-resting on theupper face of cross bar 9is a sleeve 20 designed to resiliently support the yoke of the clevis when the casing attached thereto is pulled. The upper cross bar 10 bears against an annular abutment 21 formed on the shankmember when the clevis is in its normalposition, said abutment preventing a further upward movement of the cross bar by the springs, and permitting an easy removal of the nuts from 'the yoke arms when it becomes necessary to weight will cause the springs'18 and 19 to be compressed and the upper cross 'bar 10 to rest upon the sleeve 20 which sustains the weight'of the casing. As coupling is un screwed from the end of a stand of easing the compression springs lift the stand to relieve the threads of the weight of the stand, and as there are two compression springs surrounding the arms of the yoke it will be apparent that they will have sufficient strength to accomplish same.

The springs are designed to exert an expansive force somewhat greater than the weight of a stand. The roller bearings permits the yoke and the casing to be rotated and allow any turning with a minimum of resistance.

In actual practice as in the Wigle construction a stand of casing weighs considerably over one thousand pounds, and the springs will support a load considerably in excess of said weight, thus when the springs are compressed so that the yoke 10 rests upon the sleeve 20 there is a force of one thousand pounds which lifts the weight of the stand from the coupling threads, and an excess of more than two hundred pounds tending to raise the stand as the coupling is unscrewed.

From the above it will be obvious that by increasing the resilent lifting power over the single spring construction of l Vigle a much greater load can be lifted than by such construction. Further as the elevator links hang vertically from the yoke member the weight of the casing on the clevis will be equally distributed. Also as the arms of the yoke member are secured to the upper cross bar of the clevis all danger of a yoke failure is obviated.

I claim:

.1. A hoisting clevis comprising a support pivotally secured at its upper end, an antifriction bearing on the lower end ofsaid support, a cross bar carried by said bearing having apertures formed therein, a yoke member passing through the apertures 1n the cross bar, a second cross bar on said support, the end of the yoke arms detachably engaging said second cross bar, a pair ofcoiled springs surrounding the yoke arms between the cross bars, and a support to relieve the load on the coiled springs and to limit the downward movement of the yoke when a load is imposed thereon, the yoke being free to rotate in any position.

2. A hoisting clevis comprising a shank member adapted for pivotal suspension, an anti-friction bearing carried by the free end of said shank member, a cross bar disposed on said shank member and engaging said hearing, a second cross bar disposed on said shank member above said first named bar and movable thereon, a yoke member, the arms of said yoke member passing through apertures formed in said cross bars and detachably secured to said second named bar, a coiled compression spring surrounding tween the cross bars, means formed on said shank member to limit the upward movement of said second named cross bar, and a sleeve surrounding said shank member and engaging the first named cross bar to limit the downward movement of the yoke member and to relieve the load on the springs when the latter has contracted a predetermined amount.

3. A hoisting clevis comprising a shank member for pivotal attachment, an anti-friction bearing carried by the free end of said shank member, a cross bar carried by said bearing member, a second cross bar mounted on the shank member above the first cross bar, an annular abutment formed on the shank member for limiting the upward movement of the second cross bar, a yoke member detachably secured to the second named cross bar, the arms of the yoke passing through the apertures in the first named cross bar, coiled springs surrounding the arms of the yoke member and bearing against the oppositely disposed faces of the cross bars to hold the yoke in a contracted position, and a support surrounding the shank member and engaging the first named cross bar adapted to limit the downward movement of said yoke and to relieve the load on the resilent means when the latter has contracted a predetermined amount. In testimony whereof I affix my signature.

BURT S. MINOR.

each of the arms of the yoke member -be-

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