US1374831A

US1374831A - Lifting-jack

Info

Publication number: US1374831A
Application number: US387575A
Authority: US
Inventors: William L Day
Original assignee: Individual
Current assignee: Individual
Priority date: 1920-06-09
Filing date: 1920-06-09
Publication date: 1921-04-12
Anticipated expiration: 1938-04-12

Description

W L. DAY.

LIFTING JACK. APPLICATION FILED JUNEQ. 1920.

Patented Apr. 12, 1921.

,UNITED STATES WILLIAM L. DAY, OF WILLIAMSPORT, PENNSYLVANIA.

LIFTING-JACK.

Specification of Letters Patent;

Patented Apr. 12, 1921.

Application filed. runes, 1920. Serial No. 387,575.

To all whom it may concern:

Be it known that I, WILLIAM L. DAY, a citizen of the United States, residing at Williamsport, in thercounty of Lycoming and tate of Pennsylvania, have lnvented certain new and useful Improvements in Lifting-Jacks, of which the following is aspeci-' conveniently released for either gradual or sudden return to its lowermost position.

The invention forming the subject matter of this application aims also to provide a lifting jack which is characterized by its highly simplified construction and durability and efficiency in use.

A further object of the invention, is to provide a lifting jack whichis neat in appearance, simple to operate and cheap to manufacture. e

Other objects and advantages of the in vention will be apparent during the course of the following description.

In the accompanying drawing forming a part of this application and in which like numerals are employed to designate like parts throughout the same,

Figure 1 1s a perspective of the improved 'ack;

3 Fig. 2 is a central vertical sectional view of the same;

Fig. 3 is a perspective view of apawl and releasing device embodying the invention.

In the drawing wherein for the purpose of illustration is shown a preferred embodiment of the invention, the numeral 5 designates a hollow housing provided with side walls 6 detachably secured in position by fastening devices in the form of screws 7. The standard 5 is mounted upon a flat base 8 which as illustrated in Fig. 1 is extended beyond the sides of the standard so as to provide a good bearing surface.

The upper portions of the side walls 6 are provided With spaced parallel laterally pro jecting ears lO'between which is arranged a segmental rack 12 having a, plurality of teeth lialong its outer edge. The rack 12 is rotatably connected tothe laterally projecting ears 10 through the medium of trunnions 16 which, as illustrated in Fig. 1,extends through apertures 18 in the ears. The rack 12, is, however, spaced fronithe opposed side of the ears 10 through the me dium of washers 20 which may, if desired be formed on opposite sides of the rack. The segmental rack12 is provided with a socket 22 extending radially with respect to the axes of the trunnions 16 and which receives the forward end of an operating handle or lever 24. It is obvious, of course, that 2 standard so as to allow the teeth 14-of the 7 segmental rack to extend into the standard and engage the teeth 34 formed along one longitudinal edge of the lifting bar. Since the segmental rack 12 is operatively .connected with the vertically movable lifting bar 28, a pivotal'movement of the rack 12 by a corresponding movement of the handle 2 1' will result in the elevation or descent of the bar as thetcase may be.

The means for holding the lifting bar 28 in an elevated or adjusted position com- 7 prises a pawl 38 having its free end portion curved longitudinally and engaged with a plurality of downwardly inclined locking teeth 40 formed along'one longitudinal edge. portion of the lifting bar. As illustrated in Fig. 2, the pawl 88 is arranged within an opening 111 one wall of the standard and has its lower end rounded and engaging the rounded lower end wall of the said opening so as to relieve the pivot pin 11 which extends through the same from all strain. In other words the pivot pin 11 serves merely as a means for holding the pawl 38in its proper positionand does not bear any of the strains incident to the supporting of objects by the lifting bar. The pawl 38 is yieldably pressed into engagement with the teeth 40 by a leaf spring 43 secured to one of the walls of the standard by means of a s ew b t 44 Q1 e er suitable f s nva Cir vice. The pawl 38, the opening within which the same is arranged and the spring 43 are inclosed or concealed by a cover plate 46 which is detachable so that access may at any time be had to the pawl and to the spring 43.

The pawl 38 may be released from engage ment with the teeth 40 by means of a releasing device 4L8 formed from a single length of metal having one end portion extended laterally to form a pawl engaging member 50. The pawl engaging member 50 is extended into an opening 52 in one side of the pawl and is secured in position by a rivet or other fastening device 54. The other end portion of the length of metal fIOllIWlllCll the releasing device as is formed is extended laterally in the opposite direction from the pawl engaging member 50 to form a handle 56. As illustrated in Fig. 1, the arm is extended through an L-shaped slot in one side wall 6 of the standard, which slot is provided with vertical and horizontal por tions 58 and 60. When the handle 56 is arranged within the horizontal branch 60 of the L-shaped slot, the pawl may partake of a free pivotal. movement during the ascension of the lifting bar 28 and whenthe arm 56 is manually forced within the vertical slot 58, the pawl is removed from engagement with the teeth 40. lnother words, when the arm 56 is locked in the slot 58, the pawl is arranged in inoperative position so that the lifting bar may partake of unrestricted vertical movement.

In the use of the improved jack, th arm 56 is positioned within the horizontal slot 60 so that the locking pawl 38 may partake of a free pivotal movement. With the pawl thus arranged in an operative position, the lifting bar will be securely held in an ad justed or elevated position. The rocking of the segmental rack 12 will result in the elevation of the lifting bar 28 and when it is desired to release this bar preparatory to returning the same to within the standard 5, it is merely necessary to move the arm 56 into the vertical slot 58. The lifting bar may be dropped radually by holding on effort on the part of the operator and when adjusted will not allow the accidental dropping of the lifting bar 28..

It is to be understood that the form of the invention herein shown and described is to betalren as a preferred example of the same and that such minor changes may be made as will remain within the spirit of the invention and the scope of what is claimed.

Having thus described the invention, what is claimed as new is:

A. lifting jack comprising a hollow standard, a lifting bar arranged within said standard and provided with a plurality of inclined locking teeth, a pawl pivoted to said standard, said standard being pro vided with an L-shaped slot having vertical and horizontal communicating branches, a releasing'device in the form of a length of metal having one end portion extended laterally and engaged with said pawl and its other end portion extended laterally in the opposite direction and operating in the ver-- tical and horizontal branches of said L- shaped slot, yieldable means urging the pawl into engagement with the locking teeth on the lifting bar, and means for operating said lifting bar.

In testimony whereof I affix my signature.

' WILLIAM L. DAY. [LEL]