US1459194A - Pawl and ratchet jack - Google Patents

Description

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J. H. BURKHOLDER- PAWL AND RATCHET JACK Filed May 1'7 Patented .lune 19, 1923.

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JOHN H. BURKI-IOLDER, OF ASHLAND, OHIO, ASSIGNOR T ELITE MANUFACTURING,

COMPANY, OF ASHLAND, OHIO, A PARTNERSHIP COMPOSED OF JOI-IN F. BURK- HOLDER, GUY A. COUNTRYIVIAN, AND E. L. KILHEFNER.

PAWL AND RATCHET JACK.v

Application filed May 17.

T 0 all lwhom it may Concern.'

Be it known that I, JOHN H. lumirrornnni a citizen of the United States, residing at Ashland, in the county of Ashland and State of Ohio, have invented certain new and useful Improvements in Pawl and Hatchet Jacks, of which the following is a specification.

This invention relates to improvements in pawl and ratchet jacks and has for its object to provide improved means for reversing the direction of movement of the rack for an opera-tion of the operating lever. y

ln the annexed drawings forming a part of this specification,

Fig. 1 is a vertical section showing the jack set for lifting.

Fig. 2 is a section similar to Fig. 1 showing the jack set for lowering with the lifting pawl in its uppermost position in engagement with the rack and the check pawl held out of engagement.

Fig. 3 is a section similar to Figs. 1 and 2 showing the jack set for lowering with the lifting pawl in lowermost position and released from the rack and the check pawl in engaging position.

Fig. 4 is a perspective view of the pawl tripper shown in Figs. 1 to 3.

Figs. 5 and 6 are side elevations of modified forms of pawl trippers.

Referring to the drawings the standard, 1 is a pressed steel channel member' having a front guide wall 2, flanges 3 forming side y walls, a channel bottom plate 4 having side flanges 5 riveted to the flanges 3, and cover plates 6 and 7 secured between the rear edges of the flanges 3. Slidably mounted against the front 2 of the standard 1 is the rack bar 8 having a head 9 and ratchet teeth 10 on the rear side thereof. An operating lever 11 is pivoted on a transverse pin 12 extending across between the side walls 3. A check pawl 13 is also pivotally mounted on the cross pin 12 and has a tail portion 14 eX- tending downwardly below its pivot. The lever 11, in front of the pivot pin 12 carries a pivot in 15 on which is mounted 'the lift` ing paw 16 having a tail portion 17 extending downwardly below its pivot in advance of the tail 14 of the check pawl 13; a guide bar 18 extending across between the sides 3 of the standard is engageable with a lug 19 on 1922. Serial No. 561,580.

the lever 11 to limit the upward movement of the innerV end of said lever.

Pivoted on a transverse pin 2O extending across between the sides 3 of the standard is asheet metal tripper plate 21. The tripper plate l21 has, at its lower end, a pair of lugs' through which the pivot pin 20 passes. The upper portion of the plate 21 is bent rearwardly to form a curved shoulder 23 for engagement with the lifting pawl and an upwardly extending end 24at the rear of the shoulder 23 for engagement with the tail 14 of the check pawl. A leaf spring 25 is rivet ed to the lower end of the plate 21. For

shifting the tripper plate 21 into pawl engaging position a small caml lever 26 is pivoted on the cross pin 27 to which the upper end of the cover plate 7 is secured. The cam lever 26 is formedl from a Hat angular strip of sheet metal, the forward end of which is bent inwardly to form a flat spring engaging lug 28 and the rear end of which extends through a slot in the cover plate 7 and is bent outwardly to form a finger lug and stop 29 engageable with the edge of one of the flanges 3 to limit the swing of the lever.

The pawls 13 and 16 are pressed toward the rack bar 8 by means of a spring 3U wound about the two pivot-pins 12 and 15 on which the pawls 13 and 16 are mounted and having its ends extending upwardly and engaging the backs of said pawls.

when the cam lever 26 is positioned, as shown in Fig. 1, with the rear end swung up to its upper limit of movement with its lug 29 engaging the edge ofthe flange 3 and the lug 28 against the cover plate 7, the plate 21, whose center of gravity is behind the pivot pin 20, lies in inoperative position with the spring 25 against the lug 28. When the tripper plate 21 is in inoperative position, the lifting and check pawls are held in engagement with the teeth 10 of the rack bar by means of the spring 30. During upward movement of the lifting pawl 16, the teeth 10 of the bar 8 ride past the check pawl 13 and during the downward movement of the pawl 16 the rack bar 8 is held in raised position by the check pawl 13 and the pawl 16 rides over the teeth 10 during downward movement. When the rear end of the cam lever 26 is swung down to its lowermost position, asl

until the end portion 24 thereof is moved` shown in Figs. 2 and 3, with the lug 29 in engagement with the edge of the liange 3 and the lat'face of the lug 23 in engagement with the spring 25, the end 24 of the cam plate 21 is pressed into engagement With the tail 14 of the check pawl 13 and the spring 25 acting against the flat face of the lug 28 resists movement of the lever 26 as shown in Fig. 2. Since the spring 25 is stronger than the spring 30, the pawl 13 will be held out of engagement with the rack bar when the lifting pawl is in raised position as shown" in Fig. 2. 1n this position the rack bar 8 supported on the vlifting pawl 16'. l/Vhen the outer end of the lever 11 is raised the rack bar 3 moves down with the pawl 16. Asthe pawl 16 moves down thetail 17 thereof engages the curved shoulder 23 of the tripper. plate 21. Since the weight of the rack bar is on the pawl 1,6,v the thrust of the spring 25 is not sufrici'ent to dislodge the pawl 16 from the rack bar. Consequently, the tail 17 of the plawl 16 gradually forces the plate 21 rear- Wardly against the action of the spring 25 out of engagement with the tail 14 of the cliecl; Apawl 13 Aand the said pawl 13 is movedinto engagement with the rack bar 8 by the vspring 30. Thek downward movement of the raclrbar is then stopped and on further downward movement the pawv 16 is freed fromthe tooth with which it engages and the spring 25 overcomes the spring 30 throwing the pawl 16 clear of the rack bar as shown in Fig. y3 and holding it out of engagement until the tail 16 of the pawl is raised clear of the shoulder 24, whereupon the pawl 16 is thrown into lengagement with the rack bar and lifts the bar suliiciently to free the check pawl 13 which is then thrown out of engagement by the tripper plate 21 permitting the rack bar 3 to again move down with the pawl 16.

From the above description it will be apparent that when vthe tripper plate 21 is in inoperative position as shown in Fig. 1 the rack barS is progressively7 raised in operation of the lever 11, and that when the tripper plate 21 is held in forward position as shown in Figs/2 and 3 the rack bar 8 is progressively lowered onkthe operationy of the lever 11.

In Fig. 5 a modified form of tripper is shown `cons isting of a stiff spring 31 coiled about the pivot and has one end 32 extending upwardly and rearwardly for engagement with the cani lever and a pawl engaging portion extending upwardly in front of the end 32, and having adjacent its upper end a shouldered portion 33 corresponding to the shouldered portion 23 of the tripper plate 21 and a check pawl engaging end portion 34 corresponding to the end portion 24 of the plate 21.

1n Fig. 6 a modified form of tripper is shown in which a U-shaped clip 35 having iianges apertured to receive the pivot pin has riveted to the base thereof a spring 36 which has a rearwardly extending end 37 for engagement with the cani lever and its opposite end portion extending upwardly in front of the cam lever engaging portion 32 to engage the pawls and having its upper end bent to provide a shoulder 38 corresponding to the shoulder of the plate 21 and a check pawl engaging end 39` corresponding to the end 24 of the plate 21.

Having fully described my invention what l claim'and desire to secure by Letters Patent is: i

1.` 1n a pawl and ratchet jack having a standard and a rack bar movable vertically in said standard, the combination with the pivoted lifting and check pawlsspring pressed toward said rack and engageable with the teeth thereof, Asaid lifting rpawl being mounted upon the vertically movable' operating member, said check pawlbeing mounted on a fixed pivotr and both said pawls having tail portions. extending below their pivots; of a shiftable pawl tripper having a portion engageable with the tail of said check pawl to move said pawl out of raclr engaging position; means for shifting said tripper into engaging position; and yielding means interposed between said moving means andwtripper; said tripper having a portion engageable by the tail of said lifting pa-wl during the downward movement thereoi to move said tripper the tail of said check pawl; of ashiftable tripper having its upper Vportion engageable with the tail of said check pawl to vmove said pawl out of rack engagingposition; means including a yielding element for shifting said tripper into pawl engaging position; said tripper having a forwardly projecting portion below said check pawl engaging portion engageable by the tail lof said lifting pawl during the downward movement thereof to move said tripper against the action of said yielding element to release said checlrpawl. Y f

3. ln a pawl and ratchet jack, a reversing device for engaging the check and lifting ack having a pawls, comprising a curved tripper plate pivoted at its lower end within the hollow standard of the jack for movement into and out of pawl engaging position; a leaf spring secured to the back of said tripper plate; and a shifting lever pivoted within said standard at the rear of said plate, said lever having a forward end portion engageable with said spring and a rear end portion prowhereby when said lever is moved in one direction said forward end portion thereof engages said spring to yieldingly press said tripper plate into pawl engaging position.

In testimon whereof I aiiiX my signature 15 to the following specification.

p JOHN H. BURKHOLDER.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,459,194, granted June 19, 1923, upon the application of John H. Burkholder, of Ashland, Ohio, for an improvement in PaWl-and-Ratchet Jacks, an error appears requiring correction as foiloWs: In the grant and in the heading to the printed speoieation, assignment, name of the rst-mentioned member of the partnership, for John F. Burkholder read Jaim H. Burcholcler, as shown by the records of Aassignments in this ofiiee; and that the said Letters Patent should hey read With this correction therein that the same may conform to the record of the case in the Patent Oiiice.

Signed and sealed this 24th day of July, A. D., 1923.

WM. A. KINNAN,

[SEAL] Acting om/mssz'omr of Patents.

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