US1374653A

US1374653A - Lifting-jack

Info

Publication number: US1374653A
Application number: US414458A
Authority: US
Inventors: Philip J Harrah
Original assignee: Individual
Current assignee: Individual
Priority date: 1920-10-04
Filing date: 1920-10-04
Publication date: 1921-04-12
Anticipated expiration: 1938-04-12

Description

1 P. J. HARRAH.

LIFTING JACK. APELICATIOIN nuso' OCT. 4. 1920.

1,374,653. Pat ntedApr- 12,1921.

2 SHEETSSHEET 1.

.IQ QQ 1 Zia/17% P. J. HARRAH.

LIFTING JACK.

APPLICATION FILED OCT. 4, I920. 1,374,653 Patented Apr. 12, 1921.

2 SHEETSSHEET 2.

NoRmS FEYERS, INC Lin-(0.. WASHINGTON. D. C

UNITED. ire

rarest GFFICE.

PHILIP J. HAIR/RAH, OF 'BLOOIVIFIELD, INDIANA.

LIFTING-VJACK.

. all whom it may concern:

-Be it known that I, PHILIP J. HARRAH, of Bloomfield, in the county of Greene and State of Indiana, have invented certain new and useful Improvements in Lifting-Jacks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

In-Letters Patent No. 1,307,968 issued to me June 24, 1919, I have shown, described and claimed a lifting jack having a standard formed with holes extending entirely through its thickness. A pair of runners are movable on the standard and each is equipped with a spring actuated pin for alternately entering the holes of the standard to constitute a fixed stop while the'other runner-is advancing, a-lever mechanism effecting the successive and alternate movements of the runners. The patent also I covers a. reversing element having means for controlling the projection and withdrawal of the pins to reverse the direction of travel of the runners. a

My present improvements retain the substantial features of thepatent while promoting the strength and efficiency of the device. I improve the manner ofmounting the handlever and the relative dispositions of the runners, and thereby allow the nose or step of the jack to approach close to the ground to get under low loads.

In the drawings, Figure 1 is a side elevation.. Fig. 2 is a partial elevation of the reverse side.- Fig..3 is a cross section on 3-3, Fig. 1. Fig- 4 is a section on 4-4, Fig. 1, and Fig. 5 is a detail of the reversing plate. Fig. 6 shows the lower runner.

. An upright standard 1 ismounted upon a suitable pedestaland formed with a vertical series of perforations 2 extending entirely through the standard-so that it may bereversediwhen the surfaces surrounding the perforationsbecomeworn. 3 is. the lower runner and 4 the upper runner. Each comprises asleeve rectangular in cross .section to correspond to the formation of the standard. 7 V

I provide a'maximum bearing surface for the upperjrunner, this runner itself, in turn, affording an ample bearing surface for the lower runner, instead of having each runner find its only bearing in the standard, as in the patent. The upper runner substantially Specification of Letters Patent. Patented Apr. 12 1921 Application filed October 4, 1920. Serial No. 414,458.:

incloses the lower one. Practice has demonstrated that; this arrangement materially 3 at 8 and to the lever at 9. In this way the v pitman constitutes a movable fulcrumin the lifting action and it and the-lever constitute a toggle link mechanism. l/Vhen" the runner 3-is fixed the fulcrum of the lever action is at 9 and when the runner 4 is fixed the fulcrum is at 6. The nose or step 10 is shown extending from therunner 4 from the side op'posite'to that at which the'le'ver is ful crumed.

tially-the same as in the patent.

I have shown the lower runner 3 apertured to receive a pin 12 having a cross arnr'13 and having its outer extremity movable in a bearing formed by a' bracket 14 which maybe cast integrally with the runner. A

spring 15 is shown coiled upon the pin and bears at one end against the cross arm-and at the other end against the bracket. The tendency of the spring is to project the pin The operation of the runners is subs tau inward and into one of the perforations 2 of the standard when the pin and aperforation are in alinement. ity the'pin is beveled at its upper side as at 16. By. upper sideiIhave reference to the side facing the top of the standard when the device is used in an upright position. The purpose of the bevel is that when a lifting force is exerted upon the runner to draw it toward the top of the standard the beveled surface 16 will allow the pin to slide over the wall of the perforation in which it has been seated. The straight or uninterrupted formation at the oppositeside of the pin,

as at.l7-, prevents the pin withdrawing when the ,.;weight is bearing upon the runner. When the runner is to be moved downward it is necessary to efi'ectthe drawal of the pin. I

The runner 4 is equipped with a pine 18, cross arm '19, bracket 20, spring. 21 and beveled extremity22 similar to the parts above described with relation to runner 3.

The perforations in the standard are so disposed that in the movement of the runners the pins 12 and 18 will not both be propositive with- At its outer extremjected into the perforations at the'same time.

When one pin is projected the other pin is resting or moving on the surface between two of the perforations.

From what has thus far been said it will 7 be understoodthat with the pin 12 of nunners 3 seated in a perforation as in Fig. 4,

until its'pin 12 snaps into a higher perforation. This action is continued during the elevation of the ack. v

-The reversing mechanism is shown consisting of a plate 23 having appropriate bearing spaces provided by the brackets 14 and 20. This plate is adapted to be longitudinally movable. It, has aslotted housing 2 1- moving over a guide plate 25 on runner 1. A spring 26 projects into a pocket, in the bottom of the plate and against the lower'wall of the housing. The plate 'is shown formed with upper and lower cam surfaces 2728 so disposed as to be in operative relationship to the cross arms 19 and 13. The reversing plate, is shown formed; with a flanged upper extrernity 29. A cam switch 30 is pivoted on the face of the runner 1 to contact with the extremity 29 to raise the reversing plate.

In the lifting action they reversing plate is in the position shown, that is, elevated,

against the, tension of its spring.

When the switch 30 is turned downward so that its cam surface permits the plate 23 to drop under the tension of spring 24:, the cams 27, 28 will be brought close to their respective cross arms 19 and 13.

I The subsequent operation of the lever 5 I will cause the cross arms to ride up on the cam surface and effect the positive withdrawal of the pins so as to permit the downward travel of the runners in step by step action. In this manner the toggle link mechanism which previously only permitted ofa raising action now allows of a lowering of the parts. By forming the standard with perforations extending entirely through its thickness it may be reversed so that the pins of the-runners will operate on one or the other ofits sides. After some use on one side, the left as in Fig. 1, for instance, the walls around the perforations may become worn by the action of the pins. The standard may then be turned so that its right side will receive the pins. This prolongs the term of usefulness of the standard in addition to ample 7 By the constructlon herein shown. and

described it will be apparent that the device is materially strengthened. The

upper runner at has anextended {bearing surface on the standard and as it incloses the lower runner I am enabled to place the nose or foot 10 so low that the jack may be used on any load. The relative arrangement and formation of the lower runner materially aid its maintaining a correct position in its movement on the standard.

I claim as my invention:

1. A lifting jack comprising, a standard having a plurality of perforations extending therethrough, a, pair of runners movable on 7 said standard, the upper runner substantially inclosing and forming a bearing for the lower runner, a pin carried by each of said runners for alternately entering said perforations to constitute a fixed stop while the other runner is advancing, a lever fulcrumed to one of said runners, and a pitman connecting said lever with the other runner.

2. A lifting jack comprising a standard having a plurality'of perforations extending therethrough, a pair. of runners movable on said standard, the upper runner substantially inclosing and forming a bearing for the lower runner and having a nose or foot at its lower end, a pin carried by each of said runners for alternately entering said perforations'to constitute a fixed stop while the other runner is advancing, a lever fulcrumed to one ofsaid runners, and a pitinan connecting said lever with the other runner.

3. A lifting jack comprising a standard having a plurality ofv perforations extend- 7 ing therethrough, apair of runners movable on said standard, the upper runner substantially inclosing'and forming'a bearing for the lower runner, said lower runner having a guiding plate bearing against said standard, a pin carried by each of said run ners for alternately entering said perforations to constitute a fixed stop while the other runner is advancing, a lever fulcrumed to one of said runners, an'd a :pitman connecting said lever with the other runner.

In testimony whereof I have signed thi s specification.

I PHILIP