US1175569A - Lifting-jack. - Google Patents

Description

F. C. SPENCER;

LIFTING JACK. APPLICATION FILED SEPT- I 5, 1915.

l 1 75,5 69 Patented Maf. 14, 1916.

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'me COLUMBIA xLANoGnAPu C0.. WASHlNTON, D. c.

FREDERICK C. SPENCER', OFGUILFORD, CONNECTICUT.

` marine-JACK.

Specification of Letters Patent.

Patented Mar. 14e, 1916.

Application led. September 15, 1915. Serial No. 50,763.

To all whom t may concern:

Be it known that I, FREDERICK C. SPENCER, a citizen of the United States, and resident of Guilford, in the county of New Haven and State of Connecticut, have invented a new and useful Improvement in Lifting- Jacks, of which the following is a specification.

My invention relates to an improvement in lifting jacks with the object in view of providing means for preventing the backward movement of the pinion nut when the Operating lever is swung back.

A practical embodiment of my invention is illustrated in the accompanying drawings, in which,

Figure 1 is a view of the jack in side elevation, the operating lever being shown in full lines out of operative position, and in dotted lines in operative position. Fig. 2-is a vertical central section, Fig. 3 is a transverse section in `the plane of the lineA-A, Fig. 1, and Fig. t is a transverse section in the plane of the line B-B, Fig. 1. y

The general construction of the jack is quite similar to the structure of the jack shown, described and claimed in Letters Patent No. 1,148,868, granted to me on the 3rd day of August, 1915, and need not be particularly described herein.

The pedestal is denoted by 1, the pawl carrying ring mounted on the pedestal yby 2, the double-acting pawl by 3, lthe lifting screw by 4, the pinion nut engaged with the screw by 5, and the operating lever suspended from the'pawl carrying ring 6.

It has been found inpractice necessary toy hold thepinion nut 5 with one hand, againstv a return movement while theyotherhand was working the operating lever, until suoli time as the weight on the lifting screw produced sufficient friction to hold the nut. This use` of both hands on the jack when the body of 'the operator is in the awkwardor cramped position commonly assumed under a motor car, 1s inconvenient and annoyingy and it is to remedy this-inconvenience and annoyance that my present invention is made. y

The, pedestal l is provided conveniently on the side opposite that on which the operating lever is normally located, with an upwardlyextending arm 7. At a point opposite the teeth on the nut 5, the arm 7 is provided with a bore 8 in which is freely mounted a dog 9, the inner end of which is in position to engage the teeth on the nut 5, and the outer end in position to be pressed upon by the free end of a spring strip 10, secured at its lower end to the arm 7, in the present instance by a screw l1. The dog 9 is preferably made cylindrical so that it may rotate freely in the bore 8, as well as slide longitudinally therein, and its inner end is made in a blunt conical shape so that it will present the saine degree ofy inclined obstruction to the teeth of the nut, whatever be its rotary adjustment in its bore. This will prevent the dog vfrom irregular wear as it will be free to present a new surface to the teeth at each step of rotation of the nut. The spring tension onthe dog is intended to be just sufficient to prevent a backward movement of the nut when the lever is returned for a new stroke, and the dog will sli de over the teeth of the nut as the nut is forcibly turned by the operating lever.

lVith this constructioi'i only one hand of the operator is required to operate the jack even before the weight of the object to beV lifted is exertedV on the jack andl its practical efliciency is thereby materially improved.

What I claim is:

1. In combination with a pinion nut, a lifting screw with which the nut is engaged, a Support for the nut and means for operating it, a yielding dog having a tapered end in position to engage the teeth on the pinion nut to hold it against an unintentional backward movement while permitting it forced movement.

2. In combination` with a pinion nut. a lifting screw with which the nut is engaged,

a support for the nut and means for oper ating it, a longitudinally yielding rotary dog having a tapered end in poistion to engage the teeth of the nut to prevent unintentional movement of the nut while permitting intentional movement of the saine.

y 2 Y Y 1,175,569

3. In combination 'with a pinion nut,' a spring for forcing the dog into engagement lifting screw With which the nut is engaged, With the teeth of the nut.V a support for the nut provided with an arm n In testimony that I claim the foregoing 10 extending upwardly therefrom,v the said as my invention, I have signed my name 5 arm provided with a bore opposite the nut, this 4th day of September, 1915.

and means for operatingV the nut, a rotary Y l dog seated in the bore in the armyand a FREDERICK C.v SPENCER?.-

Copies of this'patent mayY he Vobrtanedjfor vejcents each, by addressing the Commissioner of Patents,

Washington, D. C. Y

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