US1307360A - Lifting-jack - Google Patents

Description

R. B. JESTER.

LIFTING JACK. APPLICATION FILED JAN. 1|. 191s. RENEWED NOV. 21. 1918.

Patented June 24, 1919.

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7 7 I IFHVLI IYLI UNITED STATES PATENT OFFICE.

RONALD B. JESTER, OF NEW CUMBERLAND, WEST VIRGINIA, ASSIGNOR T0 HARRY A. SCHNELBAGI-I, OF FOLLANSIBEE, WEST VIRGINIA.

LIFTING-J'AGK.

Specification of Letters Patent.

Patented June 24, 1919.

Application filed January 11, 1918, Serial No. 211,331. Renewed November 21, 1918. Serial No. 263,634.

To all whom itmag concern:

Be it known that I, RONALD B. JEs'rnR, a citizen of the United States, and a resident of New Cumberland, in the county of Hancock and State of West Virginia, have invented a new and useful Improvement in Lifting-Jacks; and I do hereby declare the following to be a full, clear, and eXact description thereof.

My invention relates to lifting-jacks.

The object of my invention is to provide a jack of this character which is very strong and durable in construction, and which has the novel feature of automatically reversing the lifting-bar so that it will be lowered after the said lifting-bar has been raised to its full height.

To these ends my invention comprises the novel features hereinafter set forth and claimed.

In the accompanying drawings, Figure 1 is a side elevationof my improved jack; Fig. 2 is a vertical sectional view taken at right angles to Fig. 1; Fig. 3 is a cross-section on the line 33 of Fig. 2, Fig. 4 is a vertical section showing the parts in position forlifting the lifting-bar; Fig. 5 is a like view showin the parts in position for lowering the lifting-bar; Fig. 6 is a like view showing a slightly diflerent position of the parts from Fig. 5; Figs. 7 and 8 are details of the retaining-pawl; Fig. 9 is a section on the line 99, Fig. 4; and Fig. 10 is a perspective view of the lifting and lowering pawl.

In the drawings, the numeral 2 designates a suitable base or support which carries the frame or casing 3 inclosing the operating parts. Arranged to move vertically up and down within the casing 3 is the lifting-bar 4, which has the oppositelyrdisposed teeth 5 and 6 with the depression or recess 7 formed between the same. Located in this recess 7 and carried by the lifting-bar is the guide 8 which has the teeth 9 on one slde thereof, the other side 10 bein plain.

On the rear of the liftingar 4 are the teeth 11 which areengaged by the holdingpawl 12 which extends across the lifting-bar, said pawl being pivoted by the pins 13 to the casin 3. A spring 14 is carried by the pawl, and t e free end ofsaid spring bears against the casing 3 whereby said awl is normally held in engagement with t e teeth- 11; The

after set forth.

holding-pawl 12 is provided with the tripping-arm 15 for the purpose fully herein- The lifting and lowering-pawl 16 is mounted at its lower end on the operatingshaft 17 said pawl being cutaway at its lower end as at 18, to permit its being slipped over the crank-arm 19 of the shaft 17. The crank-shaft 17 projects entirely through the casing, being mounted in bearings 20 and 20. The outer end of said crank-shaft has the seat 21 for a ratchetarm, or a crank-arm for rotating said crankshaft. It will be apparent from the above that upon the turning of the crank-shaft 17, the pawl 16 will be raised and lowered. The pawl 16 is provided at its upper end on its inner face with the triangular-shaped lug 22 from which the stud 23 projects inwardly. The stud is movable longitudinally in the lug to permit withdrawal from guiding engagement with the guide 8 when it is desired to shift the operating pawl from elevating to lowering position for any position of the lifting bar. The stud preferably is in the form of a plunger mounted in the bore 22 of lug 22, and held in operative position by the spring 23*, the opposite end of the plunger being provided with a finger button by which the plunger may be retracted. The triangular lug 22 is adapted to engage the oppositely-arranged teeth '5 and 6 of the lifting-bar in the raising and lowering of same, as will more fully hereinafter appear.

The stud 23 is arranged to lie on either side of the guide 8, said stud being located on the straight side 10 of the. guide 8 in the operation of lifting the lifting-bar, and on the toothed side 9 on the lowering of the lifting-bar.

A spring 24 is secured to the pawl 16 at 25, and the free end of said spring bears against the inner wall of the casing 3, said spring acting normally to force the pawl 16 toward the right, as indicatedin Fig. 4.

The pawl 16 is provided with the tripping-lug 26, which is adapted to engage the trip-arm 15 in the lowering of the jack, as indicated in Fig. 6, and as will more fully appear in the description of the operation of the jack.

A spring-finger 27 is located at thejlo'wer end of the guide 8',- saidfinger being secured in the lifting bar by the screw 28. This spring is in the path of the stud 23 of the pawl 16, and acts to move said pawl over to the left, as indicated in Figs. 5 and 6, whereby thestud-23 works in and out of the teeth 9 of the guide in the lowering of the lift-ingbar, as will fully hereinafter appear.

The removable bearing plate 20 closes the opening in the casing 3 at the point where the shaft 17 extends through said casing so that by r the removal of said plate, access may be had to the interior of the casing for purposes of inspection, repair, etc.

.In the operation of my improved ack when the parts are in the position indicated in Fig. 4, and it is desired to raise, the lift ing-bar 1, the operator by rotating the crank-shaft 17, either by an ordinary ratchet-arm or by a crank applied to the seat 21, imparts a reciprocating movement to the pawl 16, which, as indicated in Fig. at, is located with the stud 23 on the plain-side of the guide 8. As the pawl 16 is lifted, it

will engage in succession the teeth 5 on the right-hand side of the lifting-bar, and on each upward movement of said lifting-pawl the lifting-bar will be lifted, while upon the lowering of the lifting-pawl, which is 7 permitted to move to-the left by compressing the spring 24, the holding-pawl will act to hold the lifting-bar in its raised position untilthe pawl has been lowered and engaged by another tooth preparatory to lifting again. In this manner, by step by step movement, the lifting-bar is raised, and when the stud 23 meets the spring 27, said spring will act to guide the stud together with the pawl over to the left, whereupon said stud is in position to engage the teeth or cams 9 on that side of the guide 8. The

operator still continues to work the operating handle in the same manner as in lifting the jack, and it will be apparent from Figs. 5 and 6 that stud 23 moving up along the cam faces of the teeth 8 will act to move the upper end of" the lifting-pawl 16 into engagement with the teeth 6 of the lifting-bar on the left of said bar upon the upward movement of the pawl, and as said pawl 16 is lowered, said pawl will carrythe weight, and, at the same time, the tripping-lug 26 engages the tripping-arm 15 and moves said arm outwardly, whereby the holding-pawl 12 is disengaged from the teeth 11 and the lifting-bar is permitted todescend by a step by step movement, just in-the same manner as the bar was lifted.

When thelifting-bar has been lowered in this manner to its lowermost position, the stud 23 will ass over the top of the guide 8, the pawl 16 being shifted automatically by the spring 2 1 over into position for lifting again.

What I claim is:

1. In a lifting-jack, the combination with a suitable frame, of a lifting-bar associated therewith, .a pawl for holding the bar in its various positions, a pawl for lifting and lowering the bar, means for raising and lowering the last mentioned pawl, and means for automatically shifting the last mentioned pawl to reversing position, said last mentioned pawl being subsequently operable to raise and lower the lifting-bar.

2. In a lifting-jack, the combination. with a suitable frame, of a lifting-bar having oppositely disposed teeth, a holding-pawl, a lifting and lowering-pawl arranged between said teeth, means for raising and lowering said last-named pawl, and means for shifting said last-named pawl to engage one or other set of said teeth.

3. In a lifting-jack, the combination with a suitable frame, of a lifting-bar having oppositely-disposed teeth, a holding-pawl, a lifting and lowering-pawl arranged between said teetlnineans for raising and lowering said last-named pawl, and means for automatically shifting said last-named pawl to engage one or other set of said teeth.

4. In a lifting-jack, the combination with a suitable frame, of a lifting-bar having oppositely-disposed teeth, a holding-pawl, a

pivotally-mounted lifting and 0 Q g pawl arranged between said teeth, means for raising and lowering said last-named pawl, and means for shifting said last-named pawl to engage one or other set of said teeth.

5. In a lifting-jack, the combination with a. suitable frame, of a lifting-bar having oppositely-disposed teeth, a holding-pawl, a lifting and lowering pawl, means for raising and lowering said pawl, a guide on said lifting bar between said oppositely-disposed teeth having cams on one side thereof, a projection on said last-named pawl lying on one side of said guide, and means for shifting said pawl to move said projection from one side to the other of said guide,

6. In a lifting-jack, the combination with a suitable frame, of a lifting-bar having oppositely-disposed teeth, a holding-pawl, a lifting and lowering pawl, means for raising and lowering same, a guide onsaid lifting-bar between said oppositely-disposed teeth having cams on one side thereof, a projection on said last-named pawl lying on one side of said guide, and means for automatically shifting said pawl to throw said projection from one side to the other of said guide.

7 In a lifting-jack, the combination with a suitable frame, of a lifting-bar having oppositely-disposed teeth, a holding-pawl, a

pivotally-mounted lifting and lowering pawl lying between said oppositely-disposed teeth, means for raising and lowering said pawl, a guide on said lifting-bar between said oppositely-disposed teeth having cams on one side thereof, a projection on smallestnamed pawl adapted to engage the teeth on said guide, and means carried by said lifting-pawl for engaging said holding-pawl whereby said holding-pawl is moved out of position when said lifting-pawl is lowered.

8. In a lifting-pawl, the combination with a suitable frame, of a lifting-bar having oppositely-disposed teeth, a holding-pawl, a lifting and lowering-pawl, means for raising and lowering said pawl, a guide on said lifting-bar between said oppositely-disposed teeth having cams on one side thereof, a projection on said last-named pawl lying on one side of said guide, a spring engaging said lifting-pawl, and means for shifting said pawl to throw said projection from one side to the other of said guide.

9. In a lifting-jack, the combination with a suitable frame, of a lifting-bar having oppositely-disposed teeth, a holding-pawl, said lifting-bar having teeth on its back face engaged by said holding-pawl, a trippingfinger on said holding-pawl, a lifting and lowering-pawl, means for raising and lowering same, a guide on said lifting-bar between said oppositely-disposed teeth having cams on one side thereof, a projection on said lastnamed pawl adapted to engage the cams of said guide, and a projection on said liftingpawl in the path of said tripping-finger whereby said holding-pawl is disengaged from its teeth on the lowering of said lifting-pawl.

10. In a lifting jack, the combination with a suitable frame, of a lifting-bar having oppositely-disposed teeth, a holding pawl, a lifting and lowering pawl, means for raisin and lowering said pawl, a guide on sai liftingbar between said oppositely-disposed teeth having teeth on one side thereof, and a withdrawable projection on said last-named pawl lying on one side of said guide, whereby said projection may be shifted to one side or the other of said guide intermediate of the maximum movement of said lifting bar.

11. In a lifting-j ack, the combination with a suitable frame, of a lifting-bar having oppositely-disposed teeth, a lifting and lowering pawl arranged between said teeth, means for raising and lowering said pawl, means for shifting said-pawl to engage one or other set of said teeth, and a spring-actuated holding-pawl on said frame engaging teeth formed on the rear of said lifting-bar.

In testimony whereof, I, the said RONALD B. J ESTER, have hereunto set my hand.

RONALD B. JESTER.

Witnesses:

Rom. D. ToTTEN, JOHN F. WILL.

Copies 0! this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. 0.

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