US1435412A - Screw jack - Google Patents

Description

i Patented Nov. 14, 1922.

i "STM SCREW JACK.

Application filed october-5, 1921;!" serial No; 5055546.

To all whom 'it may concern:l v Be it lrnown that LCHARLEs'J. MvoLTZ, a citizen of the United States, residing at Richmond,` in the county of Henricov and State of Virginia, have invented certain new and useful Improvements in Screw Jacks, of which the following is a specification. v

This invention relates to screw jacks of the portable type, and lhas for its object to y provide a jack with improved: means for raising and lowering the screw, the action being produced by a ratchet nut operated by a lever and a double-acting pawl which can be shifted to engage either way and thereby either raise or lower the screw. A further feature of the invention is a spring to hold the head against the object beinglifted while the pawl is in neutral position.

The invention is illustrated in the accompanying drawing in which Fig; l is a vertical section of the jack. Fig. 2is a top plan view with a cover plate removed to show the pawl.

The standard of the jackie indicated at 6,

resting on a base 7. The standard is hollow,f

and rectangular insection and receives the squared head 8 at the lower end of a screw 9, the upper end of which'has arocking head 10 connected to the screw by a pivot pin 11 which will adjust itself to `various angles. 'A nut 12 lits on the screw and rests at 13 on the top of the standard, and this nut can' be turned to raise or llower the screw. The nut comprises abarrel or vtubular body, and a fiange provided withnotohes 14,'said vflange being l confined between upper and lower plates 15 and 16 which will form a casing' between which `is( enclosed .a double-acting V-shaped pawl 17 having ateach .end a bevelled inturned tooth' 18 either of which may be engaged with" the notches '14, the pawl being pivoted between theplates by a pivot i 'pin 19. The position Vofl the pawl is controlled by a pin 20 pressed by a spring 21 which has a bevelled end to engage againsteither side of the point 22 at the apex of the pawl. The casing plates l5 and 16 are bolted together as indicated at 23, and the lower` plate hasfintegral therewith a lug 24 which fits in one end of a socket piece 25, to which it is bolted, the other end of the socket being the opposite` adapted to receive allever handle 26 which 4 may be removed when not "in use.'` A spring 27 is coiled around the screw below the nut"k 12, being confined. between -said 'nut and shoulderBO'on the inside ofthe standard 6. The nut lZJand thehandle parts mountedA thereon are retainedin position'with respect v n to'thestandard 6 by meansof a brace 32 the lower end of `which is attached tothe standard 6 by `screws33,'and the upper .end off which isv bent inwardly yas indica-ted at Betto", `project 'over the `nut -12,the projecting `part lhaving .an openingv through which theupper i end of the nut'ILQeXtendsyrand Atlfiebr'ace isheld in position by a small-nutBl screwed i the threaded upperend ofthe nut'12. The brace'zalso4 carries acurved' plate 35 which is pressed against theouter edge :of the' nutl.

by a coiled springi36r between said curved plate 35and the `brace 32, and said plate binds'against4 thenut with sufficient pressure Y to prevent the same slipping except when' turned by the handle 26. The standard may` also beprovided with a pin v28 extending up,-v

wardly `and serving -as a handle 'to' holdthe jack steady orto/set the same -in"pla ce. l

In operation, thejjaclr is setfunderthe obl* ject to be rliftedyand the pawll'? is 'swungl to engage the point'18thereof, the pin 20'then p p y i yThen byfswingingthe handle'back and'forth the pawl;

serving to hold the paw-L as' set.

slips-onthe back stroke and. engages inthe y mit the v'movement and the nut- 12' is thereby forwardstrolre7 thepinQO `yieldin'gto pep j turned and traveling down on the screw llar manner.y Rotation of the screw is pre`V ,Y when. Vther latter is lifted tofraise the weight;v y `To lower theweightthe paw-l is "shifted to i s position vand operated ina sini y t y 29o l vented bythe squared head` 8 in the hollow.'

of the standard.l In' Fig. 2. the `pulley-@is shown in neutral position; but'wthev active positions are obvious. i Iclaim:

f1. A jack comprising screwfincluding anut` resting on vthe standf ard and iittingon vthe screw, and a spring coiled around the screw betweenthe .nut andV i the standard.'` C l l 2. A jack comprising a standard,l a screw'. mounted thereon, lmeans to ralseor lower the, 3-

a standard,` ay screw mounted thereon, means to misc or lowx'el' the screw including a. nut resting on the stand ard and ttng on the Screw, and a bmce afttached to the standard und exendng; Mound above the nut to hold the saine on the Standard, said brace being provided with a spying friction plate bearing' aga-inst the nut.

v In testimony Wheleoi ax my Signature, .1n preence of two Witnesses.

CHAS. JOSEPH MOLTZ.

Witnesses I MICHAEL L. MOORE, MICHAEL A. MOLTZ.

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