US2570360A - Automobile jack - Google Patents

Description

Patented Oct. 9, 1951 m 'omcs AUTOMOBILE JAoK Russell H McCarroll, Dearborn, l vlich}, assignor to Ford MotofCoinpany, Dearborn, Mich," a

corporation of Delaware Application April 25, 1946, Serial No. 664,817

This invention relates to automobile jacks; and,

more particularly, to manually operated jacks of the friction type.

V The object of my invention is to provide a sup-- port rod for a friction type jack comprising a steel shaft having a noncorrosive metal sheath or'casing autogenously attached to its working surface, this sheath being hard enough to resist indentation under normal use and highly resistant to surface deterioration.

The shaft of this type of jack is particularly prone to deterioration through rusting, since any the common lubricants adversely affect the frictional n agement. Further, in normal use,' the jack may be stored for. months at a time without beingoperated in the tool compartment of the vehicle where it willbe subjected to moisture, increasing the rate of deterioration.

A further object of this invention is to provide;

an improved type of automobile jack which affords a definite support without the hazards of slippage or accidental release. A second object is to provide a jack'whioh will be positive and;

smooth in operation, and which will not stick,

jam, or slip, even after the long periods ofdisuse common with these devices.

The improvements with which rangement, construction, and combinationof thevarious parts of my improved device as described in this specification, claimed in my claims, and illustrated in the accompanying drawings, in which:

Figure 1 ,is a full-sized elevation of the jack in lowered position with'the central portion-of the housing cut away.

Figure 2 is a sectional view on an enlarged scale, takenas indicated by the lines 2--2 of Fi ure 1.

"this invention. is concerned,- are directed to the conventional otally mounted on the pin 15. The inner end' Figure 3 is a sectionalview taken on the lines I 3-3 of Figure 2. 1

'Referring now to Figure 1, the jack consists of three basic units: the shaft 2, foot plate 3" 7 into which the shaft 2 is removably inserted and the housing 4, which is substantially cylindrical in shape containing the lifting and locking mechanism of the jack and arranged for reciprocatory travel onv the shaft 2. I

g The housing 1' has, at one side, two spaced ears" I5 between 'whichthe lifting lever 6 is pivofthe lever is forked and its two extensions l8 and 22 engage the lifting dogs 5, slidably mounted on the shaft 2 as the lever is moved upwardlylto lift the housing) or downwardly (to reset the lifting dogs) respectively. The

dogs 5 are in theform of thin metal discs having a central hole with a diameter slightly larger than that of. the shaft 2 upon which they arestrung and are normally urged into position, normal to the shaft, against the shoulder 25 by the spring 23.

The housing [also encloses the locking dogs 8. which are similar to lifting dogs 5, except having a fulcrum extension l0 seated in the ful crum recess II of the housing 4 and a release.

extension I 2 projecting through the slot 2| which is a'continuation of the opening between the ears l6 through which the lever Boperates. The 1ock ing v dogs 8 are normally urged to the cocked position shown with the diametrally opposite edges ofthe holes 20 engaging the shaft 2 (see Figure 2) by the spring 11 seated on the shoulder- 25. The, upper end of'ithe housing 4 'carries a rotatable collar 9 having a notch inwhich may be s'eatedthe bumper bar or bumper bracket l9 of" the vehicle to be, lifted. 7

This structure is, it will be recognized, all

ventional and is set forth briefly, merely to assist in' anunderstanding of the invention. The operation of the-device is also conventional. Asethe lever B (usually operated through anextension;

lever inserted inthe socketf l'l) begins to move counterclockwise, the extension I8 engages the lifting dogs 5 on one side-cocking them into ing upwardly along the shaft 2, which slides freely through the. locking dogs 8. When the limit of counterclockwise rotation is reached and the lever 6 begins its return to the original position, the

initial resultant return movement of the housing 4 cocks the locking dogs 8 into engagement with shaft 2 preventing further downward movement:

of the housing, and the extension 22 restores attained. The jack is lowered by inserting a lever in the slot 2| abovethe'extensionsl2 and forcing: them downwardly, restoring the locking dogs 8 to horizontal position and permitting the housing to 'slide' downwardly on the shaft 2. As noted above, thisis. the usual mode of operation ofv jacks of this general type,

relatively noncorrosive metal, such as copperhor cadmium. Neither has been satisfactory, because the fundamental requirements for proper opera physical properties fully catalogued. For the present purpose, any of the harder brasses or bronzes are sufliciently noncorrosive. Since hardness of the coating in the drawn rod is probably the prime consideration, attention is directed to the manganese bronzes (e. g. Cu 68.5%, Al 4%, Zn 22%, Mn 3% and Fe 215%) aluminum bronzes (e. g. Cu 90% and A1 silicon bronzes (e. g.

Cu. 81.5%, Zn 4% and Si 4.5%) or the standard 10' Phosphor bronzes. While a Brinell hardness in excess of 200 would be most desirable, it may be somewhat lower and the softer alloys may also tion have been overlooked. If the'jackisto operate smoothly and easily, the main reliance in lifting and locking must be put onthe frictionalen gagement between the dogs and shaft rather than on actual physical interlocking, due to surface ole":

formation. It is true that if the shaft were quite soft; and the dogs relatively harder, the jack might be operated purelythrough successive deformation rather than-frictional engagement at least for a time. But this results in pronounced corrugation of the shaft and it is soon" foundthat the dogs will not engageand disengage smoothly and-much more to the'-point'the cor rugations will shear off under load; releasingthe jack when least expected; Actually; there is boundto be at least a transitory :deformation in the area of contact between the dog and shaft; but b keeping the surface layer hard enough; permanent deformation can be avoided; Such hardness could not, however, be'obtained' in'the plated layers of the ordinarilyavailable'metals heretofore used, since both copper and cadmium are very soft when so applied and cannot be hard ened perceptibly by available heat treatments; Even more disadvantageous was the tendency of the plated coat to strip off in use. While the bond between the plated layer and the base metal may be sufliciently' strong; for many purposes; here there a" constant succession of forces'of con"? siderable magnitude imposed on relatively" small areas resulting intransitory, if notpermanent relative deformationof the plated layer and the base. Under such service, the" bond soon fails and the entire outer layer strips away; H 'Itherefore sought a' nonoorrosi've covering for the shaft which would be-ve ry-hard, have as high" a" coefficient of friction" as possible; and would have a bond with the shaftwhich would not fail under load short of failure of the: layer itself. This combination was found to exist uniquely in a shaft prepared by fusing a layer of acopper-base alloy having high hardness characteristics'to the outer surface of a steelingot and subsequently drawing this composite structure down-w a; barof the desired diameter for the shaft in which the thickness of the alloy layeifwas about 0.010 inch or less. This process is; of course; currently used under several trade names to fabricate cop per-clad steel articles, such as bus bars-yelec'trical cables, and the like. y p

The advantage of such a; structure in this combination will beat once apparent. The" bond be tween the casing and shaft is very strong after the initial fusing or welding and isnot deteriorated in the'drawing steps. Almost any desired copper-base alloy may be used: to obtain a hard cas ing (which is not, of course; practicable with plat ing methods) and this physical characterist'ic is increased by the working incident'to the drawin operation. I do not undertake tof specify any particular alloy as most suitable, sincetlie list of copper-base alloys is readily available and the" Y) a copperbase alloyless' than 0.01" thick having further means of preventing surface defor- 'mation' is'by reducin the unit loads existing between the f'rictionally engaging members.

This may best be done by increasing the number of individual discs, making up each of the locking and lifting do gsfour being shown in use in the drawings. This is very effective in reducing deformation and provides an additional safety factor in use. 5 V

Somechanges ma be madein' the arrangement, construction, and. combination of the various parts of the improved device without departingfrom the spirit of the invention an'd it is intention to cover by the claims suchchanges as may be reasonably included in the scope thereof a V I claim asmy invention l 1. In combination, in'a friction-type vehicle.- li'fting jack, a housing-, a central su'ppo'r-ting shaft a thickness less than 0.01f and aiBrinell-hardriessin excess of 200.

2. In combination; ina friction typ vehicle" lifting jack, a housing; a cntralsupportingshaft having a steel core extending through saidhous ing, said steel core having secured thereto a rela-' tively hard exterior layer of non-corrosive metal; ayliftihgine'chanism, and a locking mechanism successively and selectively frictionally engaging said exterior layer, said exterior layer comprising ahardness in excessof 200Brir'1ll and saidm'ec'h anisms each comprise apluralityof disks su'r:

u se d efi- In n ign; a iq g i txpyehi l l f ing jack, a housing; a central sup orting shaft having a steel" core-extending through saidihous' f' me; said St el 0 16 hav n secur h r 't re. tively hard exterior layer of non-corrosive rne't a lifting mechanism, and a locking mechanism successively and selectively frictionally engaging said exteriorlayer, sa'i'd' exterior layer being'acop-f per base alloy having a Brine'll hardness in excesso'f200: w; r l. K RUSSELL H MCCARRGLE.

REFERENCES emu The following references are of record in the file of this patents UNITED STATES PATENTS

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