USRE10574E - Xwaox - Google Patents

Description

J. BARRETT. I Assignor to the DUFF MANUFACTURING COMPAN 'Y, Limited.

LIFTING JACK.

. Reissued Mar. 24, 1885.

WITNESSES:

A7 .ATTORNEYZ' UNITED STATES PATENT OEF ICE;

JOSIAH BARRETT, OF ALLEGHENY, PENNSYLVANIA, ASSIGNOR TO THE DUFF MANUFACTURING COMPANY, (LIMITED) LlFTlNG-JACK.

' SIEECIPIUA'TIUNTorming part of Reissu ed Letters Patent No. 10,574, dated March 24-, 1885.

To all whom itmay concern.- 1

Be it known that I, JOSIAH BARRETT, a citi- 'zen of the United States, residing at Alle' .moving with the lifting-bar.

gheny, in the county of Allegheny and State of Pennsylvania, have invented or discovered certain new and useful Improvements in Li fting-Jacks, of which improvements the following is a specification.

In'the accompanying drawings, which make part of this specification, Figure 1 is a side elevation of my improved jack, showing its working mechanism. Fig. 2 is a front elevation.

. My invention relates to an improvement in that class of lifting-jacks in which the liftingbar is raised by the operation of a lever carrying a pawl which engages with teeth formed along one side or edge of the lifting-bar: and the ob ectof my invent-ion" is to provide for a continuous movement of the bar either up or down; and to this end my invention consists in the construction and combination'of parts, all as more fully hereinafter described and claimed. r The box or standard A is made square or rectangular in cross-section, with a similarly-- shaped passage therethrough, and is firmly supported on the foot a by braces b. In the rear side of the box or standard is formed an opening or slot, 0, extending to nearly twothirds of its height from thel'oot upward, and

in its front side is formed an opening or slot,

d, extending downward from near the top for nearly half the length of the standard. VVithin the standard is placed the lifting-bar B, having ratchet-teeth formed on its front side, and provided at its lower and the side opposite the ratchet-teeth with the foot G,said

foot projecting out through the slot 0 and On the standard A, near the lower end of t-he slot d, are formed the brackets D I), forming between .them a recess in whichis pivoted the operating handle or lever E, the pivot-pin e of said 'lever bein g journaled'i n the brackets, as shown.

On each side of the pivotal end of the lever are secured the disks ff, which turn back and forth asthe handleor lever is moved up and down. In suitable holes in the disksff are journaled the shafts or spindlesl Z, formed on the lower end of the pawls hh. These shafts or spindles are so constructed that one end of each shaft or spindle will project beyond the brackets D D, as shown in Fig. 2, whichare provided with curved slots k, to permit of the movement of the shafts. The openiags in the disksff, in which the shafts l l arejourn'aled, are located on different sides of'a vertical plane passing through the axes of the pivot pin e of the handle or lever E, and are separateda distance equal to that between two teeth on the lifting-bar. The pawls h, and h are constructed and arranged to engage the teeth of the lifting-bar one above the other,- and are heldin such engagement by the weighted levers g and g, secured to the projecting portions of .theshaftanr-snindles.1l,..ontside of the brackets'D D. As the lever or handle is raised the outer pawl, 71, engages a tooth on the lifting-bar, thereby causing an upward movement of the lifting-bar, this upward movement-of the lifting-bar being equal to about one-half the distance between two teeth.

As the outer pawl is raised the innerpawl, h, is correspondingly lowered, such downward movement being also equal to about one-half the distance between two teeth on the lifting bar. By reversing the movement of thelever E the inner pawl and lifting-bar. are raised and the outer pawl is' lowered, the amount of such upward anddownward movements of the parts being the same as above stated. The springs s s, having two arms, as shown, are arranged outside the brackets, spring being. secured in any suitable manner to-the weighted levers g g of the 'pawls, and the other arm of each spring being arranged for engagement with the crank-arms m, secured to thesiraftn, journaled in the brackets D D, said shaft being provided at one end one arm of each with a handle, -F, whereby the shaft is turned so as to bring the crank-arms m in engagement with the springss 8 to lower the liftin gbar, the handle F is turned until the'erank arms "m cause the springs s s toengage the weighted levers g gt with con- When, it is desired- 'siderable tension, the tendency of suchtension being to overcome the action of the weighted levers, and consequently to disengage the pawls from the lifting-bar.

In describing the lowering operatidn I will suppose that the handle or lever E is in the position, shown in, Fig. 1, and that the'inner' pawl, h, is held away from the lifting-bar by the spring 8'; but that the outer pawl, h, is in engagement with the lifting-bar. Now, if the handle E be l'owered,the outer pawl and liftingbar will be lowered, such downward move ment effecting a considerable compression of the spring sas the weighted lever moves down with the pawl,'and the weight on the liftingbar prevents the pawl h from being forced outward by the action of thespring. During this downward movement of the handle and the outer pawl the inner pawl is moved up, being held away from the lifting-bar by the spring snntil near the upper limit of its movement,

at which point the spring will have reachedthe limit of its expansion, and will permitthe weighted lever. to throw the pawl into engagement, with the lifting-bar, so that as the handle E completes its downward movement the inner pawl will slightly raise the lifting-bar, thereby freeing the outer pawl from the weight of the lifting-bar, and enabling the spring sto throw said pawl away fromthe lifting-bar. As the handle Eis raised the above operation is repeated, the lifting-bar being lowered by the inner pawl, the downward movement 0f saidpawl compressing its spring 8', and the outer pawl being held away from the lift-ingbar'by its springsuntil the handle approaches the upper limit of its stroke, when the outer engages and lifts the lifting-bar so as to free the inner pawl. In-this manner a continuous uninterrupted lowering movement of the lifting-bar is effected byjthe up and down movement of the lever E, a similar movement effecting an upward movementwhen the springs are out of engagement with the weighted levers. v

I claim herein as my inyeiltion 1. In a liftingjack, alifting-bar provided with ratchet-teeth V on one side only, in combination with an operating-lever and two pawls, pivoted to said lever in such relation to-its fulcrum-point that one of said pawls, arranged to engage the lifting-bar on the same side, one above the other, will engage the lifting-bar during the upward movement of the operating-lever, and the other pawlwill engage'said lifting-bar during the downward movement of the operating-lever,substantially as set forth.

2; In a lifting-jack, a lifting-bar provided with ratchet-teeth, in combination with an operating-lever, one on each side of its fulcram-point, and springs adapted to engage said pawls and hold them alternately from engagement with the lifting-bar while they are beingraised by the operating-lever. and to permit the pawls to engage said'liftingtbar while they are being lowered, such alternate engagement and disengagement being'efl'ected automatically, substantially as set forth.

3. In a lilting -jack, the lifting bar provided with-ratchet-teeth, in combination with an operating-lever, and. pawls h h, provided with weighted levers g g, and pivoted to the operating-lever, one oneach side of its ful- I cram-point, substantially as set forth.

4. 1n a lifting-jack, a lifting-bar provided with ratehet-teeth,in combination with an operating-le ver, pawlsh h, weighted levers g g, springs .51 s, crank m, and leverF, substantially as set forth.

In testimony whereof I have hereunto set my hand.

J OSIA-H BARRETT.

Witnesses:

DARWIN S. WOLCOT'I,

H. VIIITTLESEY,

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