US787435A - Lifting-jack. - Google Patents

Description

No. 787,435. PATBNTED APR. 1a, 1905. E. 000K.

LIFTING JACK.

APPLICATION FILED JUNE 6.1904.

, pivoted on the frame A.

UNITED STATES Patented. April 18, 1905.

PATENT OFFICE.

LlF'l'lNG-JACK.

SPECIFICATION forming part of Letters I atent No. 787,435, dated April 18, 1905.

Application filed June 6, 1904. Serial No. 211,344.

To all whom, it may concern:

Be it known that I, EUGENE CooK, a citizen of the United States, residing at the city of Kalamazoo, county of Kalamazoo, State of Michigan, have invented certain new and useful Improvements in Lifting-Jacks, of which the following is a specification.

This invention relates to improvements in lifting-jacks.

The main object of this invention is-to provide an improved lifting-jack which may be tripped with comparative ease even while sustaining a heavy load.

Further objects and objects relating to structural details will definitely appear from the detailed description to follow.

I accomplish the objects of my invention by the devices and means described in the following specification.

The invention is clearly defined, and pointed out in the claims.

A structure embodying the features of my invention is clearly illustrated in the accompanying drawings, forming a part of this specification, in which Figure 1 is a side elevation view, partially in section, to show the arrangement of parts of a structure embodying the features of my invention. Fig. 2 is a detail sectional view taken on line 2 2 of Fig. 1 looking in the direction of the little arrows at the ends of the section-lines, showing the relation of the triphook F to the holding-pawl. Fig. 3 is an enlarged side elevation view of the trip-hook F in an inverted position.

In the drawings similar letters of reference refer to similar parts throughout the several views.

Referring to the drawings, A is the frame, and B is the lifting-bar, the lifting-bar being provided with suitable ratchet-teeth on one side. The shank Got the operating-lever is A lifting-pawl E is pivotally secured on the inner end of the shank (J. A holding-pawl D is supported above the lifting-pawl by a suitable pivot on the frame A. This holding-pawl is adapted to retain the lifting-bar during the downward movements of the lifting-pawl.

In operation the lifting-bar B is elevated by means of the lever.

The pawl E engages the bar, so that when the lever'is forced downwardly the bar is elevated. The retainingpawl D engages the bar and holds itin its elevated position until released or until the lever is again operated to further elevate the bar, when theoperation is repeated.

i A trip-hook F is pivotally secured at c to the shank C of the operating-lever for disengaging the pawls to release the lifting-bar. This trip-hook is adapted to engage a laterally-projecting pin e toward the upper end of the lifting-pawl E and is also provided with a laterally-projecting lug or pin f, adapted to engage the inner face of the holding-pawl D to disengage it. This lug or pin is so arranged that the pawl D is disengaged from the lifting-bar before the trip-hook acts upon the pawl Ethat is, the pawls are acted upon successively. I

The holding-pawl D is notched at d for the passage of the pin f, so that when the triphook is thrown inwardly and the operatinglever elevated it will automatically drop into place, the pin f dropping behind the pawl D.

With the trip-hook in its engaging position, as illustrated in Fig. 1, the operating-lever is forced downwardly, which, as stated, first withdraws the holding-pawl D from the lifting-bar and then the lifting-pawl E. As the line of pull is comparatively direct on the end of the lifting-pawl, it is much more easily withdrawn than the holding-pawl when sustaining a full load. By this arrangement of parts I am enabled to withdraw the holdingpawl while the main portion of the load is sustained by the lifting-pawl. The liftingpawl is then withdrawn by a comparatively direct pull on the pawl, as stated, so that I am enabled to trip the jack while under a heavy load with comparative ease. While the load is being lifted, the trip is thrown outwardly against the rest 0 on the shank, as is indicated by dotted lines in Fig. l.

The parts of my improved lifting-jack are very simple to construct and durable in use. I have illustrated and described my invention in the form preferred by me on account of the simplicity and economy of structure, although I am aware that the same may be varied in 100 structural details without departing from my invention.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a lifting-jack, the combination of a frame; a lifting-bar; an operating-lever; a lifting-pawl pivotally secured to the inner end of said operating-lever and having a laterallyprojecting pin toward its upper end; a holding-pawl having a not-ch in one edge thereof pivotally supported on said frame; atrip-hook pivotally secured to said lever adapted to engage the laterally-projecting pin on the lifting-pawl and having a laterally-projecting pin thereon adapted to pass through the said notch in said holding-pawl and engage the inner face thereof, said pin being so arranged as to withdraw said holding-pawl from engagement with said lifting-bar before said lifting-pawl is acted upon, for the purpose specified.

2. In a lifting-jack, the combination of a frame; a lifting-bar; an operating-lever; a lifting-pawl pivotally secured to the inner end of said operating-lever; a holding-pawl pivoted on said frame; a trip member pivotally secured to said lever adapted to engage said pawls successively, whereby said holding-pawl is withdrawn from engagement with said lifting-bar before said lifting-pawl is acted upon, for the purpose specified.

3. In a lifting-jack, the combination of a lifting-bar; an operating-lever; a lifting-pawl pivotally secured to the inner end of said operating-lever; a holding-pawl coacting with the said lifting-pawl; a trip member pivotally secured to said lever, adapted to engage said pawls successively whereby they are Withdrawn successively from engagement with the said lifting-bar, for the purpose specified.

In witness whereof I have hereunto set my hand and seal in the presence of two witnesses.

EUGENE COOK. [L. s]

Witnesses:

ETHEL A. TELLER, OTIS A. EARL.

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