US2174321A - Jack - Google Patents

Description

E. G. GUNN Sept. 26, 1939.

JACK Filed June 21, 1938 INVENTOR f'drZ 4 7 1.

TORNE Y5.

Patented Sept. 26, I939 UNITED STATES PATENT OFFICE JACK Earl G. Gunn, Jackson, Mich, assignor to Walker Manufacturing Company, Racine, Wis., a. corporation of Wisconsin Application June 21, 1938, Serial No. 214,961

Claims.

This invention relates to vehicle jacks, more particularly it relates to a friction type jack of the generic type illustrated and described in applicants prior copending application Serial No.

5 191,050, filed February 17, 1938, of which the present application is a continuation in part.

Jacks and lifting mechanism of the generic type disclosed herein may, in the embodiment of the invention shown, comprise a generally vertically ing is mounted for slidable vertical movement. Internally of the housing are provided a lifting plate assembly and a locking plate assembly, one of which serves to elevate the housing with respect to the column and the other serving to retain the housing in predetermined elevated position.

It is a primary object of the present invention to provide novel and improved releasing mecha nism for permitting relative downward movement arranged supporting-column upon which a housof the housing with respect to the supporting col- "umn in order that such downward movement may be smooth and yet at the same time be accurately and precisely controlled with a minimum of effort on the part of the operator;

Still further, the invention contemplates the provision of novel and improved means for controlling the -extent towhich the locking plate assembly is canted with respect to the supporting column in order that the force imposed upon the locking plate tending to grip the supporting column can be carefully regulated in order to insure smooth lowering of the jack mechanism.

Still further, the invention contemplates the provision of a particularly simple type of lowering mechanism which can, if desired, .be associated with the socket adapted to receive the lifting handle in order that by actuation of the latch mechanism, movements of the lifting handle can be utilized for the purpose of effecting lowering movements of the housing with respect to the column.

' Many other and further objects, advantages, and features of the invention will become clearly apparent fromthe following specification when considered in connection with the accompanying drawing forming a part thereof.

In the drawing: 1 50 Figure 1 is a fragmentary side elevational view of an automotive vehicle illustrating the improved jack'arranged in operative position with respect thereto.

Figure 2 is a greatly enlarged fragmentary vertical sectional view through the housing of the jack illustrating the internal construction and arrangement of parts.

Figure 3 is a. transverse sectional view taken substantially on the line 3-3 of Figure 2 illustrating in detail the mechanism utilized for re- 6 leasing the locking plates.

Figure 4 is a transverse sectional view taken substantially on the line 4-4 of Figure 2 illustrating in detail the construction and arrangement of the lifting plates.

The improved jack disclosed'herein is primarily designed for elevating automobiles in order to facilitate tire or wheel changes and is' of the type primarily intended to engage the bumper of the vehicle in order to elevate the same with respect to the gro nd- The jack comprises a base member III which serves to provide a support for a vertically extending column II which is preferably formed as a cylindrical solid rod. A housing, generally designated as I2, is formed of a pair of mating sheet metal stampings l3 and 14, each preformed to provide one half of the housing and being provided with mating flanges at each of their sides which may be'crimped together, as at E5, to lock the stampings together and provide a unitary structure.

The upper and lower portions of the stampings l3 and I! are preformed to provide semicyiindrical depressions therein which, when mated together, provide bores which snugly but slidably engage the supporting column ll. One side of the housing isprovided with a suitable aperture therein and adjacent the lower end of this aperture is pivotally mounted a lifting lever it by means of a pivot pin or rivet M. This lifting lever l6 may conveniently be formed to constitute a socket for receiving an operating handle I8. Above the lifting lever I6 is a lowering A lever 20 which is mounted for pivotal movement in the housing by means of a pivot pin or rivet 2i and this lowering lever may similarly be formed to provide a socket adapted to receive the handle l8 if desired.

As is illustrated in the drawing, the lifting lever 16 is formed of sheet metal .bent upon itself to provide at least a channel section. Between the walls of the channelsection extends a rigidly mounted pin .23, the purpose and function. of which will hereinafter become clear.

Interiorly of the housing and surrounding the column H is a compression .coilspring25, the. lower end of which is supported by the housing.-

'The'upper end of this spring serves to support a, plurality of lifting plates 26 which may con- 5% veniently be formed of sheet metal stampings and are provided with apertures therein adapted to slip over and at the same time snugly engage the lifting column ll. These lifting plates 26 have projectingears or lugs 28 which extend into the interior of the lifting lever It in order that the ing 28 of the upper-most lifting plate will lie in the path of movement of the pin 23 carried by the lifting lever [6. It is apparent that when the operating handle I! is inserted within the lifting lever and the lifting lever is then swung arcuately about its pivot by raising the handle it, the pin 23 on the opposite side of the pivot I! will follow an arcuately downward path which will effect a canting or tilting of all of the lifting plates 26 causing them to frictionally engage the surface of the column I I and thus preclude their sliding with respect to the column H. As this movement of the handle l8 continues it will be apparent that the housing I2 will be bodily elevated with respect to the column.

In order to retain the housing in elevated position as a result of the lifting action just described, a plurality of locking plates 30 is provided which locking plates are generally similar in configuration to the lifting plates 26. These locking plates 30 are supported by means of a compression coil spring 3|, the lower end of which is supported upon a cup-shaped washer 32 which rests upon the upper surface of the lifting plates 26. The locking lever 20 has a roller 35 mounted for rotation on a pin or rivet 36 which extends between the walls of the channel-like member which constitutes the locking lever. This roller is adapted to engage theupper surface of the uppermost locking plate 30 at a point spaced substantially from the axis of the column II.

In view of the fact that the spring 3| tends to urge the portions of the locking plates 30 which surround the column upwardly and in view of the fact that the roller 35 limits upward movement of these plates, it will be apparent, as is clearly illustrated in Figure 2 of the drawing, that the spring 3| serves to maintain the locking plates 30 in, normally canted or inclined position so that any force tending to cause downward movement of the housing I2 with respect to the column II will be transmitted to these plates through the lever 20 and roller 35 causing them to tilt and frictionally engage the surface of the column thus precluding downward movement of the housing with respect to the column. It will be apparent that the roller 35 forms the equivalent of a fulcrum about which the plates 30 tilt under the influence of the spring II, and that the gripping action of the plates with respect to the column will be directly dependent-upon the distance from the axis of the column If at which the roller 35 engages the plates 30.

It will be further apparent that as the locking lever 20 is swung about its pivot 2|, the roller 35 will be moved in an arcuate path which will serve to vary its distance from the lifting column. The walls of the housing members It and I l are preformed in order to limitupward movement of the locking lever 20 so that the point at which the roller 35 engages the upper surface of the uppermost lifting plate 3| will be at a maximum distance from the column II in order that when the locking lever is in the position shown, a maximum force will be available to cause the locking plates 3' to grip the column.

Due to the normally canted position of the .maintained at a uniform constant size.

locking plates 30, it will be apparent that when the lifting handle it is elevated causing a frlctional engagement of the lifting plates 26 with the column, as described above, and resulting in the elevation of the housing, the column will slide smoothly through the apertures in the looking plates 30 and freely permit elevation of the housing with respect to the column. However, any'attempt to move the housing downwardly with respect to the column will immediately cause the locking plates 30 to grip the surface of the column Ii locking the housing against downward movement. It is, therefore, apparent that the lifting handle l8 will be reciprocated through an are repeatedly and each time it is reciprocated an elevation of the housing II with respect to the column will be effected, movement in the opposite direction being precluded by the locking action of the locking plates 30 described above. When it is desired to lock the housing, the handle l8 may be withdrawn from'the lifting lever l6 and inserted in the locking lever 20. As the handle, when thus inserted, is pressed downwardly, it will cause pivotal movement of the locking lever 20 about its pivot pin 2| causing movement of the roller 35 toward the lifting column ll thus gradually but positively reducing the magnitude of the force tending to cause frictional engagement of the locking plates 30 with the surface of the column ll. As this roller 35 is moved inwardly, a point will soon be reached where the locking force, causing frictional engagement of the locking plates with the column II, will be insufficient to lock the plates against downward movement. At this time gradual slippage between the locking plates 30 and the column will take place thus permitting the housing to descend with respect to the column. This descent of the housing will cause the handle I8 to drop away from the hand of the operator thus permitting the roller 35 to move a slightly greater distance from the column H thus increasing the locking force on the column. Consequently, it will be seen that a constant downward pressure must of necessity be applied to the handle l8 when inserted in the locking lever 20 in order to effect a complete lockingof the housing with respect to the column. I

While the lowering operation may effectively be carried on in the manner described above, the presentinvention contemplates means for lowering the housing with respect to the column without removing the operating handle l8 from the lifting lever it. This mechanism includes a latch member'lli pivotally connected by means of a rivet 4| to the lifting lever at a point outwardly .of the point of pivotal co nection of the lifting lever with the housing. is latch member 40 is adapted to releasably engage a pin 42 rigidly mounted in the locking lever when the lifting lever is swung to elevated position. Consequently, it will be seen that downward movement of the lifting lever will cause pivotal movement of the locking lever 20 about its pivot 2| in much the same manner as when the handle [8 was inserted in the lifting lever 20, as described above.

It has been stated above that the sole factor which determines the proportion of the downward force exerted by the roller [6 tending to cause frictional engagement of the locking plates with the surface of the column is the distance between the point at which the roller engages these locking plates and the column. This is true so long as the apertures in the locking plates are However, it has been found that as a result of wear and use, the apertures in the locking plates 30 through which the column ll passes tend to become slightly enlarged and, consequently, greater tilting isrequired in order to obtain a locking action. It will further be apparent that when greater tilting is required, the axial distance between the points at which an individual locking plate engages opposite sides of the column will be-increased and, consequently, the force.

tending to cause tilting of the locking plates must be increased.

From the foregoing, it will be apparent that when the jack is carrying a given load, the roller 35 must be a greater distance from the column H in order to obtain an effectivelocking action if the apertures in the plates have become slightly worn. In view of the fact that the distance of the roller. from the column ll may vary throughout'a relatively wide range, a smooth lowering of the jack,may be obtained with a very substantial variation in the precise size of the apertures in the locking plates 30.

The housing members l3 and I4 are further locked together at their upper ends by means of a lifting lug 45 which includes a projecting portion 46 provided with a notch or recess 41 adapted to engage the bumper of a vehicle in order that the vertical movement of the housing may be transmitted directly to the vehicle body.

It will, of course, be apparent that the above described embodiment of the invention is merely illustrative of one form which the generic inventive concept disclosed herein may take. Many other and further embodiments falling within the scope of the present invention will become clearly apparent to those skilled in the art.

What is claimed is:

1. In a friction type lifting mechanism having a supporting column and a housing movable therealong, a cantable locking plate within said housing surrounding said column adapted when tilted to frictionally engage said column, means providing a fulcrum about which said locking plate may swing to vary the d'gree to which it is canted, means tending to cant said locking plate about said fulcrum and means for movin said fulcrum means toward or away from said column.

2.,In a friction type lifting mechanism having a supporting column and a housing movable thereon, a tilting locking plate assembly within said housing comprising a plurality of lockin plates surrounding said column and adapted when tilted to frictionally engage said column, means providing a fulcrum about which said locking plates may swing to vary the degree to ward said column.

which they are canted, means tending to cant said locking plates about said fulcrum, and means for moving said fulcrum means toward or away from said column.

3. In a friction type lifting mechanism having asupporting column and a housing movable thereon, a cantable locking plate within said housing surrounding said column and adapted when canted to frictionally engage said column, a locking lever pivotally connected to said housing, a roller carried by said locking lever adapted to engage said locking plate at a point substantially spaced from said column whereby to provide a fulcrum about which said locking plate may swing to vary the degree to which it is canted, and means for moving said locking lever to urge said roller toward said column whereby to unlock said locking plate with respect to said v tilted to frictionally engage said column, means providing a fulcrum about which said locking plate may swing to vary the degree to which it is canted, a cantable lifting plate within said housing, a lifting lever adapted to engage said lifting plate to lock the same in engagement with said column and effect elevation of said housing with respect to said column, and means releasably interconnecting said liftinglever and said fulcrum means whereby movement of said lifting lever may serve to move said fulcrum means toward said column.

5. In a friction type lifting mechanism having a supporting column and a housing movable therealong, a cantlile locking plate assembly withinsaid housing comprising a plurality of locking plates each having an aperture through which sold column passes and being adapted when canted to frictionally engage said colum housing surrounding said column adapted when movable means carried by said housing providing a fulcrum about which said locking plate assembly may swing to vary the degree to which it is canted, a lifting plate assembly comprising a plurality of plates adapted to frictionally engage said column, a lifting plates to cause frictional engagement thereof with said column and to cause bodily vertical movement of said housing with respect to said column, a. latch mechanism serving to releasably connect said lifting lever with said fulcrum means whereby movement of said lifting lever may serve to move said fulcrum means toman a. GUNN.

lifting lever adapted to cant said I

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