US1478111A - Lifting jack - Google Patents

Description

HATS Ml W. C. FARNUM LIFTING JACK Filed Oct. 2C. 1923, 2 Sheets-Sheet 1 VMM/www3 -fa Dec. S, V923;

Dec. 18, 1923.

` w. c. FARNUM LIFTING JACK 2 Sheets-Sheet 2 Filed Oct. 20. 1921 to im reve and simpli application led ctober 20, 1221.. Serial It'o. 502,993.

To all whom t may' cof/wem."

Be it own that 1, WILLIAM C. Fermin, a citizen of the United States residing at Fitchburg, in the county of Worcester and State of Massachusetts, have invented a new and useful Lifting Jack, of which the following is a specification.

rlhis invention relates to a lifting jaclr of the type in which a screw is employed as the lifting element.

It 1s the general ob'ect of my invention the construction of l such fting jacks, rendering them more emcient in operation and less expensive in manufacture.

ith this general object in view, important features ofmy lnvention relate to an improved and simplied casing construction, particularly adapted to receive and retain a considerable quantity of lubricant; to a novel disposition of the Glider-ent parts of the worm drive, permittin a worm thread to mesh satisfactorily wit a spur gear; to an improved construction of liftlng nut zo-operating with nished projections within the post ofthe jack to insure smooth d easy motion of the parts; and to a novel detachable ste end of the tubular lifting member.

M invention also includes an improved auxi iary hook or load engaging member for use with' loads which must be engaged near the base of the ack.

My invention furt er relates to arrangements and combinations of parts which will be hereinafter described and more "particularly pointed out in the appended claims.

A preferred form. oi' my invention is 'shown in the drawings, in which- Fig. 1 is a sectional elevation of my improved jack;

Fi 2 is a sectional plan view taken along the llne 2 2 in Fig. 1;

Fig. 3 is a plan view of the step or cap;

Fig. 4 is a front elevation of the lower portion of the jack partially in section;

Fig. 5 is a side elevation of the base of the jack; and

Figs. 6 and 7 are a plan view and side elevation of the auxiliary load engaging member or hook. f

Referring to the drawings, my improved jack comprises a base 10 havin an upwardly extending flange or pro]ection 11 within which is threaded the lower end of a post 12 A tubular lifting member 13 is `\surface of the or cap for the upperadj acent the slidable in bearings in the post12 and is seated at its lower end in the recessed upward extension lei of a lifting nut 15. The nut l5 and extension 14': are provided with axially extendin grooves 16 adapted to receive ribs 17 ig. 2) formed on the inner post.

The sides of the ribs 17 and the sides of the rooves are preferably formed as finishe surfaces equally and accurately spaced an larly2 so that the nut will en gage all o the rlbs in every position, thus avoiding any tendency to bend the lifting screw or to otherwise throw the parts out of alignment. 'lhe ribs 17 may be conveniently finished by the use of a tool having cutting edges accurately spaced and simultaneously engaging each of the ribs, such a tool being conveniently operated in an ordinary shaping machine.

The nut 15 is actuated by a lifting screw 18, preferably of relatively steep pitch and shown herein as havin a triple thread. A spur gear 19 is threa ed to the lower end of the screw 18 and may be secured against displacement by the use of a cross pm 20, extending through a hub 21 on the gear 19 and also through the end of the lifting screw 18.

A ball race 22 is seated in the base 10 and a plurality of balls 23 rest thereon and form an anti-friction thrust bearing for the ear 19. A shoulder Ion the lower end of t e post 12 prevents upward displacement of the gear.

Al worm 24: (Fig. 4i) is mounted in a bearing 25 in the base l() with its axis forming an oblique angle with the axis of the screw 18 and gear 19. The worm is provided with a suitable ball or thrust bearing 26 at its lower end and is secured in position by a locking pin 27. A suitable operating device or handle 28 may be detachably secured to the upper end of the worm shaft, through which the operator may apply turn the worm shown hereln as double thread.

rlhe worm bearing is placed at such an angle that the portions of the worm threads ear 19 are disposed substantially vertically, and the threads are so formed that they operatively engage the teeth of the spur gear 19. This construction is of importance, as it not onl avoids the use of an expensive worm w eel but it also permits cons ble aniall'variation power to aving a in the position of the gear.19, without affecting the-satisfactory operation of the mechanism.

A step or cap 30 is provided at the upper end of the tubular member 13, said cap having a projection 31 fitting within the member 13 and having a recess 32 extending transversely of the projection. A ball 33 and spring 34 are mounted in the recess 32 and the member 13 is provided with an internal semi-circular groove 35 adapted to receive the ball as it is pressed outward by the spring 34.

Displacement of the cap is thus prevented while at the same time the cap may rotate freely in the member 13. A small opening 36 in the member 13 permits the insertion of a pin or wire to press back the ball 33 when the parts are to be separated.

Annular recesses 37 are provided near the upper end of the post 12 to receive packings 38 which closely engage the member 13 and prevent escape of lubricant ,from the post or casing. This construction permits the whole interior of thepost 12 to be filled with oil or other suitable lubricant and eii'ectively excludes dirt therefrom. .e

In Figs. 6 and 7 I have shown an auxiliary load engaging device or hook comprising a semi-cylinder sleeve-like body portion 40 having a head 41 at its upper end and a projection or hook 42 at its lower end. The head 41 is provided with a transversely extending iiange 43 adapted to be seated in a recess 44 in the step or cap 30. This auxiliary device is extremely useful where it is necessary to lift a load which can only be engaged near the base of the 'ack.

J Having thus described my invention it will be evident that changes and modifications can be made therein by those skilled in the art within the spirit and scope of my invention as set forth in the claims, and I do not wish to be otherwise limited to tween portions of said base and post which limit axial movement thereof, and an actuating worm for said gear mounted in a bearing in the side of said base disposed at an oblique angle to the axis of the screw, said worm accurately engaging said gear in any vertical relation of said parts.

2. In a lifting jack, a non-rotatable tubular load supporting member, means .to force said member upward, a cap for said member, and a yielding locking device detachably securing said cap to said member, said means perm1tting ifree relative angular movement between said cap and-member.

3. In a lifting jack, a tubular member, a cap for said member, and means to detachably secure said cap in said member, said member having an internal groove near its upper end and said cap having a projection fitting within said member and having a locking ball yieldingly mounted in a transverse opening in said projection `in position to be retained in said groove, thereby lockin the parts together.

4. A li ting jack comprising a post, a lifting screw, a cap movable thereby, and a load-engaging member having a semi-cylindrical sleeve-like body portion an upper portion engaging said cap, and a lower hook-like projection to engage the load, the body portion closely fitting the exterior of said post.

In testimony whereof I have hereunto affixed my signature.

WILLIAM o. FARNUM.

Images