US2255261A - Lifting jack - Google Patents

Description

Sept 9, 1941- M. B. LUCKER 2,255,261

LIETING JACK Filed Dec. 4, 1939.

ATTORNEY Patented Sept. 9, v1941 ES PATEN r o-FFICE I LIF'rlNGJAcx f Millard Lucker, St. Joseph, Mich., assignor to Auto Specialties Manufacturing Company, St. Joseph, Mich., a corporation of Michigan Application December 4, 1939, serial No. 307,374 g 1s claims. (cl. -254-106) 'This invention relates to lifting jacks, and particularly to jacks of the friction gripping clamp or cam type.

It is an object of the invention to provide a friction clamp or cam lifting jack of improved construction and o'perating characteristics, and particularly to provide improved means and methods for effecting the lowering or release movements of the jack load-lifting member.

It is a further object vof the invention to provide in a friction clamp or cam lifting jack where: in the lowering or release of the load lifting member is controlled by means of the actuating clamp or cam and the jack actuating lever, means automatically operable as an incident to the movement of the actuating lever during lowering operations for moving the holding clamp or cam to inoperative release position and holding it therein during such operations.

Another object of the invention is to provide a friction clamp or cam lifting jack wherein both the actuating clamp and the holding clamp are controlled from the jack actuating lever.

More specically, it is an object of the invention to provide a friction clamp or cam lifting jack wherein the lowering or release movements of the load lifting member are under the control of the jack actuating lever, and wherein the actuating lever is operable during lowering operations to cause the actuating clamp to rst assume control of the load lifting member and thereafter to release the holding clamp whereby to effect the release or lowering of the load lifting member while maintaining control of the member at all times to effect the controlled lowering of the load.

Various other objects, advantages andv features of the invention will appear from the following specification when taken in connection with the accompanying drawing wherein a, certain preferred embodiment of the invention is set forth forl purposes of illustration.

In the drawing, wherein like reference numerals refer to like parts throughout: Y

Fig. 1 is a general side assembly view of a lifting jack constructed in accordance with one preferred form 'of the invention, two positions of the actuating -lever being shown dotted lines respectively. p

Fig. 2 is a front view of the jack structure shown in Fig. 1, particularly illustrating the lifting body and its associated parts.

Fig. 3 is a detailed perspective view of the release member or link for effecting release of the holding clamp.

in full and Figs. 4, 5 and 6`are.s ide sectional views through the jack structure of Figs. l and 2 showing the position of theV parts in various operating positions. e

Referring more particularly to the drawing, the structure shown is of the general type illustrated in my copending application Serial No. 184,174, led January 10, 1938, patented Dec. 31, 1940 as Patent No. 2,222,396 and entitled Automobile jack. The structure comprises an upstanding circular shaft l0, partially-broken away in Fig. 1', carried in any suitable manner on a baseI Il which is adapted tov rest upon the ground or other supporting surface.` A main lifting body l2 is mounted for longitudinal sliding movement along the shaft ill, the raising or lowering movements of the lifting body being under the control of friction clamps or cams, later to be described. Y

-The lifting body may conveniently be formed as a one-piece casting provided with a central bore through which the shaft lil is adapted to project. The upper end of the lifting body is provided` with a cylindrical or sleeve portion I3 adapted to support a rotatable load-engaging collar Id. The load-engagingcollar is ,providedV with a laterally projecting seat portion l5 adapted to be brought into engagement with the load to be raised, which may for example be the bumper of an automotive vehicle as illustrated by the reference numeral I6. While the lifting jack illustrated is thus of the automobile bumperjack type, it is to be understood that the principles of the present invention may be adapted to lifting jacks and related structures of other types and kinds, and adapted for other purposes. The y vlower edge of the load-engaging collar is arranged to seat upon an annular bead l'l formed on the lifting body, and the cylindrical body portion i3 is formed at its upper end with a projection i8 adapted to prevent the inadvertent dislodgement of the load-engaging collar in the event that the jack structure is inverted, as when not in use.

Referring more particularly to Fig. 4, it will bears against the lower surface of the actuating clamp 25, and normally holds it in uncanted position, as seen in Fig. 4, in seated engagement against the lifting body barrier wall 2|, the clamp being so shaped and proportioned that it is in uncanted position when seated against the barrier wall. Alcompression spring 3| also encircling the shaft I bears against the lower surface of the holding clamp 26 and normally urges it counterclockwise as seen in Fig. 4 into gripping engagement with the shaft. One end 32 of the holding clamp is loosely engaged within an opening 33 in the lifting body, the engagement 32-33 thus constituting a pivotal connection between the lifting body and holding clamp whereby the clamp may be moved counterclockwise into gripping engagement with the shaft by the compression spring. The lower end of the compression spring 3| 'seats against the barrier wall 2 l, whereas the lower end of the compression spring seats upon the extreme lower surface 34 of the lifting body.

An operating lever 35 is pivotally mounted upon the lifting body, on a pivot pin 36, the inner end of the operating lever being provided with a pair of toothed projections 31 and 38 engageable on opposite sides of the actuating clamp 25. The pivot pin 36 is mounted in a pair of laterally projecting ears 39 and 40, Fig. 2, formed on the lifting body and defining a front lifting body opening 4I. The operating lever is also provided with an extension 42, which is preferably in the form of a removable bar adapted to be received within a socket portion on the operating lever. 'Ihe bar 42 may be of any suitable length to provide the necessary leverage in the operation of the device.

In accordance with the invention the operating lever controls the movements of the actuating clamp 25 to effect both the raising and lowering of the lifting body along the shaft I0, and is also provided with means for releasing or disabling the holding clamp during load lowering operations. This disabling or release means, best illustrated in Fig. 3, comprises a release member or link in the form of a wire yoke. The yoke is provided at its lower end with a pair of inturned projections 46 and 41 adapted to be pivotally received within openings provided in the operating lever. Normally or during load raising operations the release member 45 occupies an inoperative position, as illustrated in solid lines in Fig. 1, but to effect release of the holding clamp 26 during load lowering movements, the release vmember may be pivoted upwardly into its dotted line position, in which position the cross or yoke portion 48 thereof is adapted to engage within a notch 49 formed adjacent the outer end of an outwardly extending projection 50 on the holding clamp. When the release member has been engaged with the notch 49 of the holding clamp, downward movement of the operating lever 35 will result in the moving of the holding clamp from canted to uncanted release position against the action of the compression spring 3l, as will hereinafter more particularly be described.

In the operation of the structure, the shaft III is first placed upon the base I, and the lifting body I2 is then pushed upwardly into engagement with the load, the load-engaging collar I4 first being rotated into proper load-engaging position. The lifting body may be readily moved upwardly into engagement with the load, as the actuating and holding clamps do not inhibit such movement whether in canted or uncanted position. With the load properly engaged, and assuming the release member 45 to be in its inoperative position as shown in full lines in Fig. 1, the main operating lever 35 may be actuated to effect the step by step raising of the lifting body along the shaft l0. More particularly, as the operating lever is moved counterclockwise from. its Fig. 4 to its Fig. 5 position, the actuating clamp 25 will rst be canted clockwise into gripping engagement with the shaft upon the initial movement of the lever, and thereafter serve as a reaction base upon which the inner end of the lever may be fulcrumed enabling the lever to raise the lifting body by means of the pivot pins 36. Fig. 4 shows the position of the parts prior to movement of the operating lever, and Fig. 5 shows the position of the parts at the end of the operating stroke. During the upward movement of the lifting body, the holding clamp 26 is constantly maintained in counterclockwise gripping position. The canted position of the holding clamp does not prevent the upward movement of the lifting body, but does prevent any retrograde or downward movement, the holding clamp thus serving to retain the lifting body in any position to which it has been raised. As the operating lever 35 is restored from its Fig. 5 to its Fig. 4 position, the actuating clamp is moved upwardly to a new position of engagement upon the shaft by the compression spring 30, and in the event the clamp should tend to stick, the tooth projection 38 on the operating lever positively engages and releases the clamp. The operation may be repeated to effect the step by step lifting of the load to the desired amount.

To effect lowering of the load, the operating lever is again moved from its normal position as shown in Fig. 4 or in full lines in Fig. 1, counterclockwise to an operating position such as illustrated in dotted lines in Fig. 1 wherein the release member 45 is lifted sufficiently so that it-may be pivotally moved over the projecting end 50 of the holding clamp. During this movement of the operating lever, the actuating clamp 25 will be moved away from the barrier Wall 2| and be brought into gripping engagement with the shaft. The operating lever may then be moved slightly downwardly or clockwise causing the yoke piece 48 of the release member 45 to sea-t within the notch 49 of the holding clamp projection. Further downward movement of the operating lever will cause the holding clamp to be moved clockwise into uncanted or released position, against the force of the compression spring 3|. During this entire operation, while the actuating clamp 25 remains away from engagement with the barrier wall 2|,

seated against the barrier wall and thereby be Y' uncanted and released from gripping engagement withthe shaft, causing the sliding lowering of the lifting body under the weight of the load. However, immediately as the lifting body is lowered, the operating lever 35 will again be moved counterclockwise causing the actuating clamp to be 'moved from the barrier wall and again brought into gripping engagement with forth for purposes of illustration without departing from the spirit thereof. Accordingly the invention is not to be limited vto the specic embodiment shown and described, but only as indicated in the following claims.

The invention is hereby claimed as follows:

1. A lifting jack comprising a base, a load-engaging member, means for moving the load-engaging member relative to the base comprising a pair o'f friction clamps, oner of said clamps being an actuating clamp and the other of the clamps being a holding clamp, and asingle operating lever having operative connection with both the actuating clamp and the holding clamp for controlling the movements of both theactuating clamp and the holding' clamp during load lowering operations'.

2.A lifting jack comprising a base, a loady engaging' member, means for moving the loadthe shaft, unless the outer end of the operating lever is lowered as the lifting body slides downwardly. In other words, the lifting body can move downwardly only as rapidly as the outer or lower end of the bar-42 is depressed by the operator. As a result a wholly controlled lowering of the load is rendered possible, the load.

being permitted to go down only as fast as the operator depresses the operating lever. The load may be lowered rapidly-or slowly as may be desired, but in either event the downward movement will be at all times under the operators full control and 'may be stopped immediately and automatically at any time merely by stopping the downward movement of the operating lever. During the entire lowering operation the holding clamp is held in release or inoperative position by the release member d5. After the lowering has been completed an upward, or clockwise movement of the lever enables the withdrawal of the release member 45 fromoperative contact with the extension 50 of the holding clamp, and permits the restoration of the parts to normal position, such for example as illustrated in solid lines in Fig. 1.

It will be seen that the invention thus provides, in a friction clamp or cam lifting jack, for the raising and the lowering of the load from a single operating lever, and for the automatic and maintained disabling of the holding clamp as an incident to the movements of the operating lever during load lowering operations, whereby to permit the lowering to be under the control of the operating lever and the actuating clamp. It is further to be noted that the raising and lowering movements of the lifting body are at all times under the full control of the operator. At no time are uncontrolled movements of the lifting body permitted or possible. More particularly, the holding clamp cannot be released until engaging member relative to the base comprising a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating member for the jack, means forming an opera.- tive connection between the operating member and the actuatingclamp, and means forming an operative connection between the operating member and the holding clamp, the operating member Ycontrolling the load controlling movements of both of said clamps during load lowering operations.

3. A lifting jack comprising a base, a loadengaging member, means for moving the loadengaging member relative to the basecomprising a housing and a pair of friction lclamps associated therewith, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally connected to the housing, means forming an operativeV connection between the operating lever and the actuating clamp, and means forming an operative connection between ,the 'operating lever and the'holding clamp, said lever controlling the load controlling movements of both of said -clamps during load lowering operations.

4.V A lifting jack comprising a base, a load-engaging member, means for moving the load-engaging member relative to the base comprising a housing and a pair of friction clamps associated therewith, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally Y .connected to the housing, means forming an opthe operating lever has been raised suniciently to erative connection between the operating lever and the actuating clamp, and means forming an operative connection between the operating leverand the holding clamp, said last named operative connection being selectively engageable and disengageable, and said operating lever controlling the load controlling movements of both of said clamps during load lowering operations.

5. A lifting jack comprising a base,an upstanding shaft mounted on the base, a lifting body including a load-engaging member longitudinally movableon the shaft, means formoving the 'lifting'body along the shaftcomprising i a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating member for the jack, means forming an operative connection between the operating member and the actuating clamp, and means forming an operative connection between the operating member and the holding clamp, the operating member controlling the load controlling movements of both of said clamps during the load lowering operations.

6. A lifting jack comprising a base, an upstandin-g shaft mounted on the base, a lifting body including a load-engaging member longitudinally movable on the shaft, means for movp ing the lifting body along the shaft comprising a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally connected to the lifting body, means forming an operative connection between the operating lever and the actuating clamp, and means forming an operative connection between the operating lever and the holding clamp, the operating lever controlling the load controlling movements of both of said clamps during load lowering operations. i I

7. lA lifting jack -comprising a base, an upstanding shaft mounted`on the base, a lifting body including a load-engaging member longitudinally movable on the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamps, 'one of said clamps being an actuating fclamp and the other of the clamps being a holding clamp, an operating lever pivotally connected to the lifting body, means forming an operative connection between the operating lever and the actuating, clamp, and means forming a selectively engageable and disengageable connection between the operating lever and the holding clamp, said operating lever controlling the load controlling movements of both of said clamps during load lowering operations.

8. A lifting jack comprisinga base, a load-engaging member, means for moving the load-engaging member relative to the base comprising a housing and a pair of friction clamps associated therewith, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally connected to said housing, a portion of said lever being adapted to engage the actuating clamp to effect the movement thereof, and a link connection between the operating lever and the holding clamp, said link connection being selectively movable to operative and inoperative positions, and said operating lever controlling the load controlling movements of both of. said clamps during load lowering operations.

9. A lifting jack comprising a base, an upstanding shaft mounted on the base, a lifting body including a load-engaging member longitudinally movable on the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally connected to said lifting body, a portion of said lever being adapted to engage the actuating clamp to effect the movement thereof, and a link connection between the operating lever and the holding clamp, said link connection being selectively movable to operative and inoperative positions, and said operating lever controlling the load controlling movements of both of said clamps during load lowering operations.

10. A lifting jack comprising a base, a loadengaging member, means for moving the loadengaging member relative to the base comprising a housing and a pair of friction clamps associated therewith, one of-said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally connected to said housing, a portion of said lever being adapted to `engage the actuating clamp to effect the movement thereof, and a link connection between the operating lever and the holding clamp, said link being pivotally connected to the operating lever and selectively engageable and disengageable with the holding clamp.

11. A lifting jack comprising a base, an upstanding shaft mounted on the base, a lifting body including a load-engaging member longitudinally movable on the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally connected to said lifting body, a portion of said lever being adapted to engage the actuating clamp to' effect the movement thereof, and a link connection between the operating lever and the holding clamp, said link being pivotally connected to the. operating lever and selectively engageable and disengageable with theI holding clamp.

12. A lifting jack comprising a base, an upstanding shaft `mounted on the base, a lifting body including a load-engaging member longitudinally movable on the shaft, means for moving the lifting body along the shaft-,comprising a pair of friction clamps, one, of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally connected' to said lifting body, a portion of said lever being adapted to engage the actuating clamp to effect the movement thereof, and a link connection between the operating lever and the holding clamp, said link comprising a wire yoke member pivotally connected to the operating lever, and said holding clamp being provided with a notched projection with which the wire yoke member is selectively engageable and disengageable.

13. -A lifting jack comprising a base, a loadengaging member, means for moving the loadengaging member relative to the baise comprising a housing and a pair of friction clamps associated therewith, one of said clamps being an actuating clamp and the other of the clampsl being a holding clamp, an operating lever pivotally connected to the housing, means forming an operative connection between the operating lever and the actuating clamp and means forming an .operative connection between the operating lever and the holding clamp, said means being operable as the lever is pivotally moved in a' selected direction to move the actuating clamp into operative position to support the load-engaging member and thereafter to disable the holding clamp.

14. A lifting jack comprising a base, an upstanding shaft mounted on the base, a lifting body including a load-engaging member longitudinally movable on the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally connected to the lifting body, means forming an operative connection between the operating lever and the actuating clamp and means forming an operative connection between the operating lever and the holding clamp, said means being operable as the lever is pivotally moved in a selected direction to move the actuating clamp into operative position to support the load-engaging member and lthereafter to disable the holding clamp.

aessai 15. A lifting jack comprising a base, an upstanding shaft mounted on the base, a lifting body including a load-engaging member longitudinally movable on the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivotally connected to said lifting body. a portion of said lever being adapted to engage the actuating clamp to eiiect the movement thereof, and a single integral member operatively connecting the operating lever and the holding clamp, said integral member being adapted to directly engage the operating lever and the surface of the holding clamp.

16. A lifting jack comprising a base, a loadtween the operating .lever and the holding clampA whereby the movements of the operating lever may control the operation of said holding clamp.

MILLARD B. LUCKER..

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