US1762400A - Lifting jack - Google Patents

Description

June 10, 1930. 5 LUCKER 1,762,400

LIFTING JACK Filed March 16. 1926 2 Sheets-Sheet l Z- r' Z4 Z June 10, 1930. M. B. LUCKER 1,762,400

' LIFTING JACK Filed March 16. 1928 2 Sheets-Sheet 2 1206427?? WZzZZm aZ 1E. Zu claw Patented June 10, 1930 PATENT OFFICE MILLARD B. LUCKER, OF BENTON HARBOR, MICHIGAN, ASSIGNOR '[0 AUTO SPECIAL- TIES MFG. (10., OF SAN FRANCISCO, CALIFORNIA, A. CORPORATION OF CALIFORNIA LIF'IING JACK Application filed March 16, 1926.

This invention relates to lifting acks for all purposes but especially for use in automobiles.

The invention relates to the particular flf'class of lifting jacks in which a toothed lifter-bar is operated by a lifting pawl and a holding pawl or detent. The object of the invention is to furnish ineans actuated by the hand-lever of the jack for raising the lifter-bar step by step, or lowering it step by step; which. has fewer parts and operates more eiiiciently than prlor known devices.

The invention consists in mechanism capable of attaining the foregoing and other objects; which can be easily and cheaply made; which is highly satisfactory in operation and is not readily liable to get out of order. More particularly, the invention 0 consists in numerous features and details of construction hereafter more fully set forth in the specification and claims.

Referring to the drawings in which like numerals represent the same parts throughout the several views:

Figure l is a side elevation, taken just inside the front cover of a jack, illustrating this invention in its'preferred form.

Figure 2 is a side elevation, taken on the irregular line 2-2 of Figure l.

Figure 3 is a plan view on the line 3-8 of Figure l. t

Figure 4 is a side view of the jack of this in- .vention ready for work.

35 Figure 5 shows the operative parts of the device in the position assumed when just starting to raise the lifting bar the length of one rack tooth.

Figure 6 shows the same parts in maxi- 40 'niuni upper position on the lifting stroke.

Figure 7 shows the operative parts in the operation of load lowering just after they begin to move. i I

Figure 8 shows a subsequent intermediate position of said parts.

Figure 9 shows the same parts at rest on substantial completion of the lowering operation.

The jack is enclosed within a U-shaped Serial No. 95,035.

at the open side of the case by rivets 14 passing through suitable spacing blocks 16 not shown in detail. The jack case is sustained on a base or foot 18 being secured thereto by suitable rivets 20.

Vertically slidable inside case 12 is a coilventional form of lifting bar 22 equipped at its top with a load engaging block 24 and provided along its side, opposite to the open edge of the case with a rack 26 provided with downwardly pointed ratchet teeth of conventional form.

Pivotally mounted on a stud or shaft 28 is an upper holding ratchet dog 30 normally urged into engagement with the upper portion of ratchet 26 by the upper end 32 of aspring whose central portion is wound in a coil 84: around a projecting end of stud 28, spring end 32 bearing on :1 lug 35 on said dog 30. The opposite or lower end 36 of this same spring projects downward from coil 3% into engagement with a lug 38 projecting from one side of a lifting ratchet pawl or dog 40, pivotally carried at its lower end on a pin or stud 42 on operating lever socket 4d operatively engaged by hand lever 46, socket 44 being journaled at 48 on use 12.

The parts just described, when left to themselves, operate in entirely conventional manner, viz.: dog 30 always engages a tooth of rack 26; during downward movement of lever 46 from the position of Fig. 5 to that of Fig. 6, dog d0 interlocks with a tooth of rack 26 and consequently forces the rack 26 upward while dog 30 clicks over one tooth, and during the return movement from the position of Figure 6 to that of Figure 5, dog clicks over a rack tooth whiledog 30 is engaged, it firmly holding bar 22 stationary.

Projecting from the face of case 12 at a point below journal pin or stud 48 is a screw stud 5O performing the double function of securing the lower end of supplemental cap 52 to case 12 and acting as a pivot for cam lever 54 rockable inside the cap 52 between the positions shown in the figures. The upper end of cap 52 is detachably secured in place by a screw 56.

Lugs 35 and 38 project through slots 58 and 60 in the front wall of case 12 into the path of lateral movement of cam lever 54 and the latter is urged into engagement with said lugs by a heavy spring 62 bearing at one end on the interior of cap 52.

Stud 48 projects into the interior of cap 52 and there carries a reversing lever 64 manually movable from outside the cap between the positions of Figures 5 and 6 in which it holds cam lever 54 entirely clear of studs 35 and 38 and the positions of Figures 7, 8 and 9 wherein lever 54 is operative to force dogs 30 and 40 to operate as hereafter described. When the operator wishes to do straight lifting, he places lever 64 in the position of Figures 5 and 6 and when he wishes to use the jack in lowering, he turns this lever to the position of Figures 7, 8 and 9.

Cam lever 54 carries a cam part 66, en-

I gageable with lug 38, so shaped and arranged that in the position of Fig. 7, the lifting dog 40 is held out of engagement with the particular tooth of rack 26 engaged in lifting but is ready to engage the next succeeding tooth of the rack. Lever 54 also has an upper angular end 68 shaped and arranged to engage stud 85 on pawl 30 and make it operate in conjunction with dog or pawl 40 during the lowering operation, as hereafter described.

Assume'that a load 70 is on block 24; that all the parts are in the position of Figure 7 and that lowering of the load is desired. The operator moves lever 46 from the position of Fig. 7 to that of Fig. 8 during which movement, stud 38 travels off from cam part 66 and dog 40 passes into engagement with a tooth of rack 26 thus lifting the rack one-fourth the length of one rack tooth, i. e., to the position of Fig. 8, thus allowing pawl 30 to fly out of engagement with rack 26 as shown in that figure. This movement of pawl 30 was prevented in the position of Fig. 7 by the fact that the pressure of the load 70 on pawl 30 was too great for spring 62 to overcome.

Having reached Figure 8 position, the operator allows lever 46 to swing upward, under pressure of load 70, with the result that rack 26 moves downward. As the position of Figure 9 is reached, the upper end of lever 54 ceases to control dog 30. Near the end of the downward travel of the lifting pawl, which pawl is at such time firmly engaged with the rack because of the load thereon, the pin 38 strikes the cam surface 66 of the cam lever 64 and forces the latter to swing clock-wise, thus temporarily overcoming the action of the spring 62. Spring end 32 throws the dog to the right into engagement with a rack tooth and simultaneously cam part 66 of the lever reaches the position where it is just ready to move dog 40 from the position of Figure 9 back to that of Figure 7, ready to begin another step of the lowering operation.

Line 72 is provided in Figures 5 and 6 to show that in lifting, load 70 travels up the length of 1% rack tooth before settling back to one tooth length. Similarly, line 74 is provided in Figs. 7, 8, 9 to show graphically that load 70 is first raised tooth length above Fig. 7 position and then lowered 1 tooth length. The play of an extra rack tooth length is required to allow the dogs 30 and 40 room for movement between the difierent positions described.

Attention is particularly called to the fact that the upper end of lever 54 travels twice as far and twice as fast as cam part 66 about stud 50 with the result that holding dog 30 is released twice as quick as dog 40, thus insuring safe operation of the device.

From the foregoing description, it is evident that lever 54 is a spring actuated pawl modifying or reversing device in that when in operative positions of Figures 7, 8 and 9, it changes the method of operation of the pawls from lifting as in Figures 5 and 6 to lowering as in Figures 7, 8 and 9.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a lifting jack, a casing, a toothed lifting bar, a holding pawl, a holding pawl pivot pin carried by said casing and projecting at one end beyond one side of the casing, a hand lever, a pivot pin for said hand lever carried by the casing and projecting at one end beyond one side of the casing, a lifting pawl carried by said hand lever, a spring mounted upon the projecting end of said holding pawl pivot pin and engaged at its ends, respectively, with said holding and lifting pawls for urging the latter into engagement with the teeth of said lifting bar, a relatively long integral pivoted cam member having an end extending adjacent the uppermost of said pawls and pivoted to swing to a position to efiect release of said pawls from said lifting bar upon predetermined movement of said hand lever, a spring for so swinging said cam member, and a positioning lever mounted upon the projecting end of said hand lever pivot pin for movement to a position in which it engages with and holds said cam spring means for forcing said holding dog and lifting dog into engagement with said lifting bar, a relatively long cam lever pivoted to said casing below the pivotal point of said hand lever and extending upwardly past said lifting dog and adjacent said holding dog, said cam lever having co-operative portions for engaging both the lifting dog and the holding dog, and a reversing lever pivotally mounted on the pivotal axis of said hand lever and dapted to engage the cam lever, and' a spring adapted to throw said cam lever into engagement with said dogs when released by said reversing lever.

3. In a lifting jack, in combination with spaced apart parallel plates forming the side cheeks of the jack, of a rack bar slidable vertically therein, a hand lever pivot ally mounted betwen said cheeks, a lifting ,dog pivotally carried by the inner end of said hand lever and adapted to engage the tooth lifting bar, and a holding dog pivotally mounted between said cheeks and adapted to engage the tooth lifting bar, one of said cheeks having openings therein, a relatively long cam lever pivotally mounted on the exterior of said cheek and adapted to extend adjacent said openings and having portions adapted to engage with portions of the two dogs which pass through the open ings in the cheek, a reversing lever pivotally mounted on the pivotal axis of the hand lever on the exterior of said cheek, and a cap adapted to cover said cam lever and a portion of said reversing lever.

4. In a lifting jack, in combination with spaced plates forming the jack cheeks, a tooth lifting bar vertically mounted between said cheeks, one of said cheeks having spaced apart openings therein, a holding pawl and a lifting pawl pivotally mounted between said cheeks and having portions adapted to project through said openings in the cheek, a hand lever pivotally mounted between said cheeks and connected to the lifting dog for operating the same, spring means for throwing said dogs into engagement with the tooth lifting bar, a relatively long cam lever pivotally mounted on the exterior of the cheek that has the openings therein, a reversing lever mounted on the exterior of said perforated cheek and adapted to operatively engage the cam lever, and a cap adapted to cover said cam lever and a portion of said reversing lever, and a pivotal bolt for said cam lever, said bolt also forming a means for holding the cap in position.

5. In a lifting jack, in combination with the spaced apart side plates of the jack, a tooth lifting bar slidably mounted between said plates, one of said plates having spaced openings therein, a hand lever pivotally mounted between said plates, a lifting dog pivotally mounted on the inner side of said hand lever, a holding dog pivotally mounted between said plates above said lifting dog, lateral portions on said dogs passing through the openings in one of said plates, a spring adapted to engage said laterally projecting portions of said latter dogs, a reversing lever pivotally mounted on the pivotal axis of said hand lever, a relatively long cam lever pivotally mounted on said casing below the pivotal axis of said hand lever and having a portion adapted to e11- gage the reversing lever and having a cam portion, above said first mentioned portion, adapted to engage the lateral portion of said lifting dog, said cam lever having a relatively long upper end adapted to engage the lateral pivotal portion of said holding dog and a spring normally urging said cam lever towards said reversing lever.

6. In a lifting jack, a case comprising a single sheet of material formed to provide a vertical U-shaped channel and providing spaced cheek plates, a tooth lifting bar arranged for axial movement within the bight of the U-shaped frame and means for effecting axial movements of said bar with respect to said frame, said means comprising a pivot pin carried by said casing and projecting beyond one of said cheek plates, a holding pawl pivotally mounted on said pivot pin, a hand lever, a pivot pin for said hand lever mounted in said frame having an end extending through one of the cheek plates, a lifting pawl carried by said hand lever, a spring mounted upon the projecting end of the holding pawl pivot pin and engaging at its ends the holding and lifting pawls to norn'ially urge the same to engage the teeth of said lifting bar, a pivoted cam member having portions extending adjacent both of the pawls to release the same from engagement with the teeth of the lifting bar upon predetermined movement of said hand lever, a spring normally urging said cam member towards pawl-releasing position, and a pushing lever mounted upon the projecting end of said hand lever pivot pin and movable into the path of said cam member whereby to prevent the same from moving to pawl releasing position.

In witness whereof, I l ave hereunto subscribed my name.

MILLART) B. LUCKER.

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