US2243739A - Vehicle jack - Google Patents

Description

May 27, 1941- AqOBERi-IOFFKEN VEHICLE JACK Filed Jan. 2, 1940 2 Shets-Sheet l INVENTOR. ALA-"1 9N059 055/? FF/KEA/ RNEYS Y X M/ ATO y 1941- A. OBERH-OFFKEN VEHICLE JACK Filed Jan. '2, 1940. 2 Sheets-Sheet 2 N .E 5 ZJW ZMM E o W T I A Patented May 27, 1941 UNETED STATEfi TNT GME (lakland County, ican Forging &

Southfield Township,

Mich., assignor to The Amer- Sccket Company, Pontiac,

Mich, a corporation of Michigan AppiicationJanuary 2, 1910, Serial No. 311,972

Claims.

This invention relates to lifting jacks. While readily applicable to lifting a wide variety of loads and objects, jacks constructed in accordance with the invention are especially suitable for use as accessory equipment adapted to be supplied as a part of the tool equipment of motor cars, to enable raising the vehicle when necessary, as to change a tire or perform other operation requiring the services of a jack.

An important object of the invention is to provide such a jack which is lighter in weight and less expensive to construct than presently known jacking devices of comparable strength, all of the major parts of which are formed of sheet metal, yet which is of very much greater strength in proportion to its weight than jacking devices of this class as now constructed, and very positive and reliable in operation.

Another important object is to provide in such a lifting jack an improved sheet metal standard adapted to replace the relatively costly and heavy screw shafts and the like now commonly employed to sustain the load. A related object is to incorporate novel and simplified lifting means adapted to coact with the standard to raise the load in a very simple and easy manner, by lever action.

As is well known, the lever principle permits exertion of greater lifting eifort in proportion to the work involved than is possible with the use of a screw shaft, since the latter principle involves great frictional losses which can be largely eliminated in devices operating upon the lever principle. Screw shafts have nevertheless been widely used in the construction of jacks for automotive vehicles, for the reason that structures heretofore designed and operating upon the lever principle have not provided as great strength and security in proportion to their weight and cost. The present invention aims to overcome the shortcomings of previously known jacks of the lever type, and to provide a jack in which screw shafts and other parts which would impose undue frictional losses are eliminated, yet in which sheet metal parts of very simple and inexpensive character are substituted, which substituted parts are of great strength and provide very secure and positive operation.

A further object is to provide in such a jack improved means for preventing unwanted rotation between the lifting cage and the standard on which it travels.

Other objects and advantages will be apparent from the following description, wherein reier- Cal ence is made to the accompanying drawings il lustrating a preferred embodiment of my invention and wherein similar reference numerals designate similar parts throughout the several Views.

In the drawings:

Figure 1 is a side elevational view of my imimproved lifting jack, the standard and handle being partly broken away.

Figure 2 is a view of the same upon a larger scale, partly in side elevation and partly in vertical section.

Figures 3, 4 and 5 are horizontal sectional views taken respectively on the lines S3, i l and 55 of Figure 2, and looking in the direction of the arrows.

Figure 6 is a side elevational View of the jack takenirom the right, as viewed in Figure 1, the handle and a part of the base being broken away.

Figure 7 is an elevational view taken as indicated by the line and arrows ?-7 of Figure 2; and

Figure 8 is an elevational view of a base of somewhat modified construction.

Referring now to the drawings, reference character l6 designates the standard of the jack The standard is formed of sheet metal, longitudinally bent to the form of a tube of substantially triangular cross section, as best shown in Figures 4 and 5. The standard is adapted to be fitted into and supported by a sheet metal base l2, having a socketed portion i 3 of generally similar shape-to receive it, as shown in Figure 3. Positioning prongs as M may project down-' wardly from the corners of the base to insure better engagement with the supporting surface, and to guard against slipping.

The longitudinal edges of the sheet metal of which the standard is formed are turned outwardly and lie beside one another, to form in effect a single laterally projecting flange !5, of double thickness. These flange-forming edges may be welded together, although this is not necessary if the material used is sufficiently hxeavy. serrations H are formed along the flanged edge thus provided.

Vertically slidable upon the standard is a cage assembly generally designated 26, also formed of sheet metal, constructed in flanged sections which are welded or otherwise secured together, as at the welded points designated 2!. Laterally extending load-sustaining arms 22-23 project from the upper portion of the cage, preferably in three directions, as shown, and these are adapted to underengage the load to be lifted, such as the running gear or bumper of a vehicle.

An operating handle portion 25, also formed of sheet metal and having one arm extending upon each side of the cage, is pivoted at its inner extremity to the cage, as upon the cross pin 21, the outer end of handle portion being socketed, as indicated at 28, to receive an extension handle 30.

Pivotally attached to the handle portion 25 by means of a cross pin 32 is a U-shaped strap element 33 which extends angularly upwardly into the cage and encircles the standard, its bight portion being serrated conformably to serrations l1, and adapted to interengage such serrations. Strap 33 constitutes a lifting strap, by which the cage is raised upon the operation of the handle, as will presently appear. A cooperating holding or clutch strap 35 is also provided, which acts to prevent the cage from moving downwardly while the lifting strap is being advanced by the handle for successive lifting operations, as also will more fully appear in a subsequent explanation of the operation of the device. The clutch or holding strap will be seen to be formed similarly to the lifting strap 33, but to be pivoted directly to the cage, as upon a pin 31. The holding strap is also disposed angularly, and provided with a serrated bight portion encircling and interengageable with the serrations I1 formed upon the standard.

A spring 40, of leaf form, is arranged in the cage, between laterally projecting flange portions 4| thereof, in such manner as to bear against the bight portions of both of the straps 33-35, to urge the same into holding engagement with the standard. A lower portion 42 of the spring, which bears against the holding portion of the strap 33, is of sufiicient vertical length to allow for longitudinal movement of such strap with relation to the cage. An upper portion 43 of the spring bears against the upper extremity of the holding strap 35. This strap is not bodily movable vertically with respect to the cage. The upper holding portion 43 of the spring is swingable outwardly to the position indicated in dotted lines in Figure 2, and tends to assume this position when relaxed, thereby permitting the bight of the holding strap 35 to swing downwardly and outwardly, away from the standard. When a load is to be lifted, the spring is maintained in the holding relation in which it is shown in full lines in Fig. 2, in which position it maintains strap 35 at all times in yieldable engagement with the serrations of the standard. Selective holding and release of this portion of the spring is effected by means of a cam 45, formed of a simple length of heavy wire, projected through the side flanges 4i of the cage and having a central ofiset or crank section serving as the cam, and a laterally bent finger portion 46, lying outside one of the flanges, to permit convenient swinging of the cam to either of the two indicated positions, one of which is designated Up and the other Down.

When a load is to be lifted, the finger :portion 46 of the cam is swung to the Up position, spring portion 43 being thereupon forced to maintain the yieldable engagement between the clutch strap 35 and the serrated portion of the standard. A simple up-and-down pumping movement of the handle portion then lifts the cage, while upon each upward movement of the handle the cage rests, held by the clutch strap, and the lifting strap is raised to secure a higher grip upon the serrations l'l. During downward movement of the handle, the latter pivots about the pin 32, which is then securely supported by the strap 33, due to the strong frictional and interlocked engagement between strap 33 and the standard. The action of the sheet metal straps will be seen to be similar to the action of a rope, thong or cloth as used by natives in the tropics to climb trees. The direction of the pull provides the secure frictional grip, and the load upon the cage, in the present construction, tends to force the upper or bight portions of the straps more tightly into engagement with the standard, so that slippage is impossible. As the handle is moved downwardly, one component of the downward force draws the strap 33 firmly against the standard, with a grip so secure that the handle assumes and sustains the load, and acts as a lifting lever, raising the cage thr-u its connection thereto at 21, while pivoting upon pin 32 as a fulcrum. During such lifting movement, strap 35 ratchets over the teeth or serrations I1, and immediately resumes its support of the cage when downward efiort upon the handle is relaxed. While the cage is thus supported by the clutch strap or holding strap 35, the handle 30 may be lifted, at which time it pivots upon the pin 21, and the strap 33 is thus raised to permit engagement with higher serrations, whereupon the lifting operation may be repeated by downward movement of the handle. Upward movement of the strap 33 as the handle is lifted will be seen to be guided by the fiat section 42 of spring 40, which section at the same time constantly urges the strap into holding engagement with the standard.

When the load is to be lowered, finger portion 45 is swung downwardly, to the position designated Down. The upper portion 43 of the spring then no longer urges strap 35 into holding engagement with the standard. When the handle is lifted with the spring thus released, the holding strap 35 is freed, and the cage may slide down the standard under the weight of the load, while the lower strap 33 is also forced upwardly by lifting effort upon the handle.

A cam portion 50, formed upon the handle section 25, between the side arms thereof which extend upon opposite sides of the standard, is adapted to engage the standard when the handle is raised, and it will be seen that by lifting upon the handle this part may be made to clamp the standard very tightly, to enable its use as a brake to slow the descent of the load.

In the somewhat modified base construction shown in Figure 8, the socket for reception of the lower end of the standard is formed by a separately inserted flanged cup, the center of the base being simply pierced to receive the cup section, designated I3A, while its out-turned flanges, 13B, are welded to the base proper. This composite construction will be seen to simplify the drawing operations required to form the base.

While it will be apparent that the illustrated embodiments of my invention herein disclosed are well calculated to adequately fulfill the objects and advantages primarily stated, it is to be understood that the invention is susceptible to variation, modification and change within the spirit and scope of the subjoined claims.

What I claim is:

1. In a lifting jack of the type having a standard adapted to be fixedly supported, and a load supporting cage adapted to travel up and down the standard to lift or lower a desired load, lifting means for raising the cage with respect to the standard, comprising an operating handle pivoted upon the cage, a lifting strap pivoted upon the operating handle at a point spaced from the axis of connection of the handle to the cage, said strap' being frictionally engageable with the standard upon downward swinging movement of the handle with respect to the cage, said frictional engagement being sufficient to prevent downward movement of the handle and of the cage connected thereto while eifort is exerted downwardly upon an outer portion of the handle, whereby the cage may be forced upwardly by downward movement of the outer extremity of the handle, such movement causing the handle to pivot upon its axis of connection to said strap, and one way clutching means preventing unwanted downward movement of the cage when such eiTort upon the handle is released.

2. Means as set forth in claim 1 in which said one way clutching means comprises another hold ing strap having a holding portion engageable with one side of the standard and pivoted to the cage upon one side of the portion of the standard engaged thereby, and extending angularly upwardly and around the standard, said holding strap being swingable to frictionally engage with the standard and adapted to be tightly clamped thereagainst by a component resulting from loading of the cage, thereby positively preventing downward movement of the cage, and releasable spring means for urging said holding strap into such frictional engagement with the standard.

3. A lifting jack comprising a substantially tubular sheet metal standard of non-concentric cross section, a lifting cage slidably fitted on said standard and having a portion interfitted with and guided by a non-concentric portion of the standard, whereby the cage is keyed against rotation with respect to the standard, lifting means including a lever articulated to the cage, a portion operable by the lever and interengageable with the standard to lift the cage step-by-step along the standard, and clutch means for preventing unwanted downward movement of the cage with respect to the standard.

4. A load supporting standard for a lifting jack or the like, comprising a metal sheet bent longitudinally to substantially tubular form, and to bring opposite longitudinal edges of said sheet into abutting relation, said edges being outturned to provide longitudinally extending flange means, an edge of such flange means being provided with serially disposed abutment portions adapted to coact with load sustaining means carried by a carriage slidable along said standard.

5. Means as set forth in claim 4 in which said standard is of non-circular cross section, and said out-turned edges lie at the juncture of angularly disposed sides thereof.

6. In a lifting jack, in combination with a standard adapted to be supported in upstanding position to sustain a desired load, and having a longitudinal series of abutment portions serially disposed along one face thereof, a cage slidably fitted upon said standard to directly engage and support the load during lifting thereof, and means for forcing said cage upwardly along said standard, comprising a handle pivoted at its inner end to the cage upon a substantially horizontal axis, a lifting strap pivoted to said handle upon an axis substantially parallel to and spaced from the first mentioned axis, said lifting strap extending angularly upwardly from said handle and around said standard having cooperating holding portions interengageable with said abutment portions carried by the standard, the axis of connection of said strap lying between said first mentioned axis and the outer end of the handle, whereby said handle by downward effort exerted upon its outer extremity may be rocked about its axis of connection to the strap, and may act as a lever to lift the cage, and one way clutching means preventing unwanted downward movement of the cage with respect to the standard when the downward effort upon the outer end of said handle is released, whereby such outer end of the handle may be lifted to swing the same about its first mentioned axis of connection to the cage and thereby raise said strap to interengaged relation with abutment portions positioned higher along said standard, to permit repeating of said lifting operation.

7. Means as set forth in claim 6 including spring means resiliently maintaining said strap element in said interengaged relation with the standard as the strap is moved along the standard during lifting movement of the handle, whereby holding engagement of the strap and standard is re-effected when lifting effort upon the handle is released.

8. Means as set forth in claim 6 in which said one way clutch means comprises a second, holding strap pivoted upon the cage and extending angularly upwardly and around the standard and having holding portions adapted to coact with said abutment portions carried by the standard, and releasable spring means for yieldably swinging said second mentioned strap element upwardly to maintain said holding portions thereof in engagement with said irregularities.

9. Means as set forth in claim 6 in which said one way clutch means comprises a second holding strap pivoted upon the cage and extending angularly upwardly and around the standard and having holding portions adapted to coact with said abutment portions carried by the standard, and common spring means carried by the cage for yieldably urging both of said straps into holding engagement with the standard, said spring means also acting as guide means for said lifting strap during upward movement of said strap in response to upward movement of the handle.

10. Means as set forth in claim 6 in which said one way clutch means comprises a second holding strap pivoted upon the cage and extending angularly upwardly and around the standard and having holding portions adapted to coact with said abutment portions carried by the standard, a spring portion movable to and from a stressed position in which it urges said holding strap into holding engagement with the standard, and a second spring portion constantly urging said lifting strap into holding engagement with the standard. 4

ALEXANDER OBERHOFFKEN.

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