US1584549A - Lifting jack - Google Patents

Description

D. A. KEATING LIFTING JACK May 11 1926.

2 Sheets-Sheet 1 Filed Oct. 13 1924 vlllllflll vv May 11 1926. 1,584,549

D. A. KEATING LIFTING JACK Filed Oct. 15, 1924 Q 2 Sheets$heet 2 V /III/Il/IIIHIIIIIIIII ll Patented May 11, 1926.

HEB) STAT DANIEL A. KEATING, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THE AMERICAN TUBE AND STAIVIPING COMPANY, OF BRIDGEPORT, CONNECTICUT, A CORPORATION OF CONNECTICUT.

LIFTING JACK.

Application filed October 13, 1924. Serial no. 743,444.

This invention relates to lifting jacks such as those commonly used in automobiles and particularly to a jack adapted to be manufactured of pressed steel.

In United States Letters Patent No. 1,503,- 3d3, dated July 29, 1924;, there is illustrated and described a jack of this type and one of the objects of the present invention is to simplify the construction of the spring for actuating the pawls, this simplification of the spring construction being advantageous in that it reduces the cost of production and facilitates assembly of the pawls, spring and associated parts in the jack casing. A simplified arrangement of the spring and its associated parts is also contemplated as this increases the ease with which the parts may be assembled.

The present invention also contemplates a novel form of mechanism for reversing the action of the spring.

With these and other objects in view the present invention consists in certain novel details of construction and combinations 5 and arrangements of parts all as will be hereinafter more fully described and the novel features thereof particularly pointed out in the appended claims.

In the accompanying drawings,

Fig. 1 is a vertical sectional view of a jack embodying the present invention, the pawl spring in this instance being shown in the position it occupies when the jack is employed for lifting a load.

Fig. 2 is a similar view except the spring is shown reversed for lowering the load.

Fig. 3 is a detail view of one of the pawl springs, two springs of like construction being preferably employed.

Fig. 4 is .a detail view of the lower or retaining pawl.

,The greater portion of the jack is designed to be produced from pressed steel, casing 10 being preferably made with a longitudinally extending channel therein and with rearwardly extending side portions 11, forming a housing for the operating mechanism. At its lower edges the casing is flanged, as at- 12, whereby the casing may be secured to a base 13, as by rivets or spot welding and to strengthen the casing it can be formed with gussets 14 in its lower portion.

'The load supporting rack 15, which is also preferably of channel shape, is slidably mounted in the casing channel, teeth 16 beingstruck out from the metal constituting the base of the rack. A head 17 is mounted on the upper end of the rack which not only takes the load but also closes the end of the channel for the purpose of preventing dirt entering the casing or gaining access to the working parts. A projection 2O struck up fromthe lower end of the base of the rack channel works in a longitudinal groove 21 extending part way of the front wall ofcasing 10 .and prevents the rack being entirely withdrawn from the casing.

The lifting pawl 22 is preferably of the form illustrated in the patent heretofore referred to, being hollow and having side walls which extend from the front wall towards the rear which is entirely open. The pawl is pivoted at one end on the operating handle socket 23 and its opposite end is formed with a transverse bridge piece which is perforated, as is also the front wall of the pawl, for a purpose which will presently appear. Socket 23 for the operating handle 24 is pivoted on a pin 25 carried by side walls 11, the rear of the casing being open in order to .allow the socket to be rocked as will be understood. The parts so far described are old and form no part 'of the present invention, except in combination with the elements now to be described.

As is usual, there is a retaining pawl pivoted in the casing below the lifting pawl the two pawls being urged either towards or from the rack by a spring, depending upon whether the load is being elevated or lowered. In order that the retaining pawl and spring may be assembled in the casing after the rack, lifting pawl and operating lever socket have been placed therein, the present invention contemplates a retaining pawl construction and spring arrangement which will permit the retaining pawl, spring and .spring reversing mechanism to be preliminarily assembled as a unit and then inserted in the casing.

In the preferred embodimentof the invention the retaining pawl 26 is hollow, having a perforated front, side walls, and an open rear side, the opening in the front being substantially in alinement with the openings in the lifting pawl when the retaining pawl is pivoted in the casing on the pin 27. The alined openings in the two pawls are adapted to receive the end portions of one or more vertically disposed springs 28, preferably two, whose central portions are offset transversely of the casing and rack, these offset portions being held in a perforation in the free end of a pivoted spring lever 29 projecting above the retaining pawl and which may be rocked on its pivot to flex the central portion of the springs toward or away from the rack whereby the ends of the springs will urge the pawls in the opposite direction.

Preferably, the spring lever is pivoted 0n the same pin as the retaining pawl and extends between the sides of the retaining pawl, thus conserving space and insuring the application of the spring pressure to the transverse central portions of the pawls, although the use of two springs necessarily causes the spring pressure to be properly distributed to the pawls.

The use of a spring that is only otl'set at its center, transversely of the casing, reduces the cost of production. Furthermore, the use of a straight spring combined with the fact that the spring is arried by the lever and the lever in turn is carried by the pin on which the retaining pawl is pivoted permits the parts to be assembled preliminarily as a unit, more or less, and then inserted in the casing. This can be done by placing the springs in the spring lever, then placing the lever between the sides of the retaining pawl with the lower end of the spring extending through the opening in the front of the pawl.

The parts can then be placed in the easing, it only being necessary to see that the upper ends of the springs enter the two )erforations in the lifting pawl. This, however, is an easy matter as the perforations are practically in alinement.

To reverse the direction in which springs 28 are flexed and thereby reverse the action of the jack, a cam lever 30 is pivoted on a pin 31 in the casing in position to have its cam surfaces 32 engage transversely projecting lugs 3i formed on the lower end of spring lever 29. By moving cam lever 30 upward to the position in which it is shown in Fig. 1, cam surface 32 forces lug 33 and the upper end of the spring lever toward the rack which will have the effect of causing the ends of the spring to urge the pawls toward the rack. The parts occupy these pasitions when a load is to be elevated. By moving cam lever 30 down to the position shown in Fig. 2, the upper end of the spring lever is moved away from the rack due to the fa rt that the lug 3i which is then engaged by cam surface is located below the pin 2? and the upper end of the spring lever is above said pin. This reverses the action of the jack.

Yfhen a load is being elevated the )awls are yieldingly held in engagement witn the rack teeth so that when the operating lever depressed elevating pawl will engage one of the teeth and elevate the rack one tooth. During each upward movement a tooth slips past the retaining pawl but the latter holds the rack each time the clcvatil'ig pawl is being retracted by the lever 24: to engage another tooth and again elevate the rec To lower the load the action of the spring is reversed to hold the pawls out of engagement with the rack except when the load is imposed on whichever pawl is in engagemei'it with one of the teeth. To lower the rack, the operating handle. as shown in Fig. 2. B; depressed and elevating pawl elevated, during which movement a cam surface 255 formed on the casing 10 will engage the sides of the pawl and move it into er.- gagcment with the rack. A slight additional depression of the operating handle will relieve the retaining pawl 01 its load whereupon said pawl will be disengaged by the springs. The operating handle, carrying the load, is then raised but. as the inner end of the handle socket moves down, a cam 36 formed thereon will engage the retaining pawl and force it under one of the teeth so that said pawl will sustain the load while the operating lever is being lowered to repeat the operation just described. These modes of operation for raising and lowering the rack are like those of the patent hereinbefore mentioned and the only feature that need be emphasized here, is that the spring actuating lever is so arranged as to lie below the side walls of the retaining pawl where it will not interfere with the cam 36, on the socket properly functioning to move the retaining pawl into engi gement with the rack when the latter is being lowered.

hat I claim is:

1.. In a device of the character described, the combination of a casing, a slidablc rack in the casing, pivoted lifting and retaining pawls adapted to engage the rack. an operating le er for actuating the lifting pawl, a spring supporting and shifting lever having one end pivoted in the casing and having its opposite end perforated, said spring supporting lever and retaining pawl having a common pivoted center, a spring having its central portion supported in said perforation and having its free ends engaging the lllt) pawls, and a cam for rocking said spring lever to flex the central portion toward or away from tl e rack and urge the ends thereof and the pawls toward or away from the rack, said spring remaining flexed. in the same direction, depending upon the position of said cam, during oscillations of the op erating lever.

2. In a device of the character described, the combination of a casing, a slidable rack therein, a lifting pawl, an operating hand lever, a hollow retaining pawl, a spring for urging the pawls toward or away from the rack, a lever supporting said spring, said lever lying between the sides of the hollow retaining pawl, and a cam for rocking said lever to determine the direction in which the spring will tend to move said pawls.

3. In a device of the character described, the combination of a casing, a slidable rack therein, lifting and retaining pawls, one of said pawls having spaced side walls, an operating handle for the lifting pawl, a spring supporting and flexing lever pivoted in the casing, the free end of said lever being located between the spaced side walls of said pawl, a spring having its central portion offset transversely of the rack, said central portion of the spring extending through the free end of the spring lever and the free ends of the spring engaging said pawls, and means for moving the free end of the spring lever toward and away from the rack to determine the direction in which said springs will urge the pawls.

4. In a device of the. character described, the combination of a casing, a vertically movable rack therein, lifting and retaining pawls engageable with said rack, each pawl being hollow with front and side walls, the back of each being open and there being an opening in the front of each pawl, a verically disposed spring having free end portions extending through the openings in the pawls, a spring actuating lever engaging the central portion of the spring and movable toward and away from the rack, said spring lever and one of said pawls being pivoted on a common shaft, means for moving the lever and spring and holding the same in either of their adjusted positions, and an operating lever for the lifting pawl.

5. In adevice of the character described, the combination of a casing, a vertically movable rack therein, lifting and retaining pawls engageable with said rack, each pawl being hollow with front and side walls, the back of each being open and there being an opening in the front of each pawl, a vertically disposed spring having free end portions extending through the openings in the pawls, a spring actuating lever pivoted in the casing below the upper end of the retaining pawl and extending between the sides of the retaining pawl, the free end of said lever projecting above said retaining pawl and engaging the central portion of the spring and movable toward and away from the rack, means for moving the lever and spring and holding the same in either of their adjusted positions, and an operating lever for the lifting pawl.

6. In a device of the character described, the combination of a. casing, a slidable rack therein, a lifting pawl, a hollow retaining pawl having front and side walls, an operating lever for the lifting pawl provided with a cam surface adapted to engage the side walls of the retaining pawl, a spring supporting lever extending betweenthe side wallsof the retaining pawl but spaced from the cam surface on the operating lever, a spring carried by said spring lever and engaging said pawls and means for rocking said spring lever to urge said pawls toward or away from the rack.

7 Ina device of the character described, the combination of aicasing, a vertically slidable rack therein, lifting and retaining pawls pivoted within the casing, an operating lever, a spring engaging said pawls and adapted to urge the same toward or away from the rack, and a spring supportlng lever pivoted 1n the casing, said sprlng supporting lever and the retaining pawl having a common pivotal center.

8. In a device of the character described, the combination of a casing, a vertically slidable rack therein, lifting and retaining pawls pivoted within the casing, an operating lever, a spring engaging said pawls and adapted to urge the same toward or away from the rack, and a spring supporting lever pivoted in the casing, said spring supporting lever and the retaining pawl having a common pivotal center, the free end of the spring supporting lever projecting above the retaining pawl and having said spring connected thereto.

9. In a device of the character described, the combination of a casing, a slidable rack therein, a pivoted lifting pawl, an operating lever for said pawl, a retaining pawl pivoted in the casing, a spring for urging said pawls toward or away from the rack, a lever in which said spring is supported for determining the direction in which said spring will urge said pawls, and means for rocking said lever, said spring lever and retaining pawl having a common pivotal center and said lever, spring and retaining pawl being removable from the casing substantially as a unit.

10. In a device of the character described, the combination of a casing, a slidable rack therein, a pivoted lifting pawl, an operating lever for said pawl, a retaining pawl pivoted in the casing, a spring for urging said pawlstoward or away from the rack, a lever for determining the direction in which said spring will urge said pawls, and a pivot pin on which both the retaining pawl and said spring actuating lever are mounted, said spring, lever and retaining pawl being assembled in the casing; in substantially unitlike form.

11. In a device of the character described, the combination of a casing. a vertically slidable rack therein, lifting and retaining pawls pivoted in the casing, an operating lover, a spring engaging said pawls and adapted to urge them toward or awa v from the rack, a spring supporting and actuating lever pivoted in the casing on a eonunon shaft with the retaining pawl, and a cam lever engaging said spring actuating lever and projecting outside of said casing for rocking said lever to flex the spring toward or away from said rack.

12. In a device oi": the character described, the combination of a casing, a vertically slidable rack therein lifting and retaining pawls pivoted in the casing, an operating lever a spring engaging said pawls and adapted to urge them toward or away from the rack, a spring actuating lever pivoted in the casing, said retaining pawl and spring actuating lever having a common pivoted center lateral lugs on said spring actuating lever, and a cam lever engaging said lugs to rock said lever toward and away from said rack.

DANIEL A. KEATIXG.

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