US1538896A - Lifting jack - Google Patents

Description

May 26, 1925.

G. JENSEN LIFTING JACK Filed Aug. 14, 1924 3 Sheets-Sheet 1 G. JENSEN LIFTING JACK May 26, 1925.

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G. JENSEN LIFTING JACK Filed Aug. 14, 1924 3 Sheets-Sheet 5 H I n wmv l w um m 6 m IN w Patented May 26, 1925.

UNITED STATES I 1,538,896 PATENT OFFICE.

GUNNAB JENSEN, OF RAGINE, WISCONSIN, ASSIGNOR TO WALKER MANUFACTURING COMPANY, OF RACINE, WISCONSIN, A CORPORATION OF WISCONSIN.

LIFTING JACK.

Application filed August 14, 1924. Serial No. 782,023.

To all whom it may concern:

Be it known that I, GUNNAR JENSEN, a subject of the King of Denmark, residing at Racine, in the county of Racine and State of Wisconsin, have invented certain new and useful Improvements in Lifting Jacks, of which the following isiagspecification.

This invention relates to thlfclassofdevices known as lifting jacks, and more particularly to such a device designed to have an exceptionally long lift in proportion to its size and height when in collapsed or lowered position.

While ,the uses for such a jack are innumerable, it is especially adapted for advantageous use in the automotive industry with the new oversized or balloon tires. For this use it is desirable to have a jack which is compact and of small vertical height when lowered, in order to be placed underthe low axle or other frame part when the tire is collapsed, and capable of a comparatively long lift to elevate the car above its normal driving height in order that the tire may be changed.

The jack is of that type employing a plurality of screws working one within another and each contributing its share to the total lift of the jack. According to this invention the screws are telescoped or nested within one another and within the standard of the jack when in lowered position, and driving connections are provided whereby upon a continuous rotation of the driving means, which may be operated from a distance, the screws are simultaneously operated so that each will exert its lifting power upon the load. According to the preferred embodiment of the invention here shown by way of example, two nested screws are employed,

the outer screw being an exteriorly threaded sleeve which meshes with a stationary nut formed in the standard of the jack. The inner screw meshes within a nut formed in the upper end of the outer screw sleeve. Means are provided to hold the inner screw against rotation at all times but allow it to move vertically. Driving means, keyed to the outer sleeve, rotate the same continuousy in one direction thusmoving it upthrough the stationary nut, and at the same time the outer sleeve acts as a nut to elevate the inner non-rotary screw. Rotation of the-driving means in the reverse direction will lower the parts to the original position.

forth in more detail hereinafter, providing improved means for holding the inner screw against rotation while it allows the screw to move up completely out of the standard,

and providing a compact and sightly jack, in whichtheparts are easily assembled and readily accessible.

Other objects and advantages of the invention will be readily apparent from the following detailed description of several different types of jacks embodying the principles of this invention.

In the accompanying drawing:

Fig. 1 is a central vertical section through one of the preferred forms of jack, showing the jack in partially elevated position.

Fig. 2 is a transverse section taken substantially on the line 2-2 of Fig. 1.

Fig. 3 is a transverse section taken substantially on the line 3-3 of- Fig. 1.,

Fig. 4 is a central vertical section through a slightly modified form of the jack.

Fig. 5 is a similar view through another modification.

Fig. 6 is a transverse section taken substantially on the line 66 of Fig. 5.

Fig. 7 is a central vertical section through another modification.

Fig. 8 is a horizontal section taken sub stantially on the line 8-8 of Fig. 7.

Fig. 9 is a horizontal section taken substantially on the line 99 of Fig. 7.

Fig. 10 is an elevation of the jack shown in Figs. 7, 8 and 9, on a somewhat smaller scale.

I will first describe the very similar forms of jacks shown in Figs. 1 to 10 inclusive, and will-refer more particularly to the forms shown in Figs. 1, 2 and 3. The stationary standard for the jack comprises a substantially cylindrical hollow casting 1, having a broad supporting base 2. At its upper end the standard 1 is formed with an integral .upwardly extending annular ring 3 which is in'teriorly threaded to. form 'a stationary nut. A rotary driving member 4, here shown as a beveled gear, is journaled and supported upon the upper end of nut 3. A cover plate 5', having a bearing at 6 for the upper portion of gear 4, is removably secured to the standard 1 by screws or similar devices 7 Journaled in an extension 8, at

one side of cover plate 5, is a short stubshaft 9, having a small beveled pinion 10 formed at its inner end or keyed thereto. Beveled pinion 10 meshes with and drives the beveled gear 4. The outer end of shaft 9 is provided with a socket 11, to cooperate with any suitable form of removable handle whereby the jack may be operated from a distance. It will be noted that the shaft 9 tilts upwardly so that the operators end of the handle will be elevated to a convenient position.

The lifting members comprise a pair of oppositely threaded screw members 12 and 13, which are nested one within the other wherrtl ie j ack is in lowered position. The outer screw 12 is iiithaform' Ora hollow sleeve exteriorly threaded to mesh with the stationary nut 3. Keys 14 are mounted in sockets 15 in opposite sides of gear 4, these.

keys engaging in vertically extending keyways 16 formed in diametrically opposite sides of the exterior portion of sleeve12. A downwardly extending annular flange 17 on the lower side of gear 4, engages a corresponding groove or channel in the top of nut 3 to center the gear. One of the keys 14 has been omitted, at the right of Fig. 1, to more clearly illustrate the sockets 15 and flange 17. The central opening in gear 4 is of such size that the screw sleeve 12 can move freely vertically therethrough, but the gear 4 and sleeve 12 will always rotate as a unit due to the engagement of the keys 14 in the keyways 16 in the screw. Ihe inner screw 13 meshes with a nut 18 formed in the upper end of the outer screw sleeve 12. A load-supporting cap 19, rockingly mounted as hereinafter described, is secured to the upper end of the inner screw 13. Each of the two screws is of substantially the same height as the standard, and when the ack is in lowered position are enclosed completely within the standard except for the loadsupfiorting cap 19.

ovably suspended within the annular space 20 between the inner and outer screws, is a comparatively thin metallic tube or sleeve 21. At is lower end this sleeve is provided with outwardly extending lugs 22 which travel up and down in slots 23 formed vertically in diametrically opposite sides 9f the standard 1. Vertically extending slots 24 are cut in diametrically opposite sides of Cir the tube 21, as here shown these slots being spaced ninety degrees from the lugs 22. Short pins or projections 25 at the lower end of screw 13 are adapted to travel up and down in the slots 24. It will be noted that the tube 21 is locked againstrotation. at all times by the lugs 22 moving in the slots 23 in the stationary standard 1, and that in turn the inner screw 13 is locked .to the tube 21 by means of the pins 25 engaging in the slots 24 in the tube. By this means, al-

though the screw 13 may be elevated bodily completely out of the standard 1, as shown in Fig. 1, it is at all times locked to the standard in such a manner that it cannot rotate. This improved locking means is housed at all times within the standard and lifting members, and does not add to the size of the jack assembly, nor present any unsightly projections upon the exterior thereof.

In operation, the jack, in collapsed or l0wered position as shown in Fig. 5 with a slightly modified form of jack, is inserted beneath the member to be elevated. The removable handle is-thenirgerted in the socket 11, and, with the parts threaded as shown in the drawing, is rotated continmin a clockwise direction. gear: 4 and screw sleeve 12in a counter clockwise direction, as viewed from above, and will cause this'outer screw 12 to elevate itself through the stationary nut 3. At the same time, the inner screw 13, which is not allowed to rotate, will be carried bodily upward by the sleeve 12, and furthermore will be elevated with relation to sleeve 12 by the rotary nut 18 formed in the upper end of the sleeve. The two screws 12 and 13 will be simultaneously operated to each contribute its share to the elevating process, regardlless of whether any load is carried by the load-supporting cap 19 or not. It will be noted that the extreme height of the jack when in extended position is nearly three times its height when in lowered or callapsed position. \Vhen the jack is to be lowered, the handle is rotated continuously in the opposite direction, and the parts resume their original'position by a movement exactly the reverse of those previously described.

In the modification shown in Fig. 4, the stationary nut 26, instead of being formed as an extension of the standard 1, is formed integrally with the cover plate 27 and located above the driving gear 28. The stubshaft 29, corresponding to the shaft, 9 previouslysdescribethis journaled -in a housing extension 30 at one side of the upper end of standard 1. T he shaft 29 carries the beveled pinion 31 meshing with and driving the gear 28; Driving gear 28 is journaled upon an annular flange 32 at theupper end of standard 1. and both screws move freely up and down through the standard. Otherwise this jack is constructed and operates substantially the same as the form previously described.

The modification shown in Figs. 5 and 6 is similar to that shown in Fig. 4, with the exception that a different device is used to hold the inner screw against rotation. A rod or bar 33, having a square or other angular cross section, replaces the tube 21 previously described. This member 33 projects This will rotate m up within the inner screw 34 which is hollow, and has a sliding fit within a correspondingly shaped aperture 35 in the lower end of the screw. A plate 36 secured to the lower end of rod 33, has lugs or projections 37 which move up and down in vertical slots or grooves 38 in the standard 1. Lugs 37 prevent rotation of the rod 33, which in turn, due to its angular cross section, prevents rotation of the inner screw 34:. At the same time the screw 34 can move freely upwardly until the head 39 on rod 33 is en countered, after which rod 33 can slide upwardly through the standard with the lugs 37 traveling up in the slots 38. Otherwise this jack operates similarly to the form previously described.

The modification shown in Figs. 7 to 10 inclusive illustrates the substitution of a worm and worm-wheel drive for the beveled gear drive previously described. In this modification, the stationary nut 3 is formed at the top of the standard 1, as in the form shown in, Fig. 1. The worm-wheel 40, which has straight vertical teeth 41 similar to a spur-gear, is journaled at 42 about the outside ofthe nut 3 and has an inwardly extending flange 43 su orted upon the upper end of the nut. eys 44 placed in recesses in the flange 43, engage in vertical slots or grooves 45 in the outer screw sleeve 12 so that the worm-wl1ee l and sleeve will always rotate as a unit. Aworm 46, mounted on an inclined axis as shown in Fig. 10 within a housing extension 47*of cover plate 48 meshes with and drives the worm-wheel 40. An anti'friction thrust bearing 49 is provided between the worm46 and one face of the housing, and a socket 50 is provided at the outer end of worm shaft 51 to accommodate the removable operating handle. The inclined position of worm 46 serves the double function of permitting the worm teeth to properly mesh with the vertical teeth 41 of worm-wheel 40, and also tilts the operating handle u wardly at the proper convenient angle. he-sleeve or-tube. 21 and cooperating parts for holding the inner screw 13 against rotation are substantially the same as described in connection with Figs. 1 to 4 above. The use of this worm drive as shownin Figs. 7 to 10, provides a greater gear reduction than is possible with the beveled gearing pa'eviously shown, and hence adapts thisjaekfor lifting heavier loads.

As shown more particularly in Fig. 7, the load-supporting cap 19 is provided with an interior recess 52 which loosely surrounds a reduced extension at the top of the inner,

screw 13, the cap resting upon the rounded surface 53 at the top of this extension. A pin or rivet 54 in the cap projects. loosely into an opening 55 in the screw to prevent removal of the cap 19. By this means the load-supporting cap 19 is allowed a certain universal freedom of. movement so that itinay adapt itself to any slight tilting of the load supported by the jack without necessitating any corresponding tilting of the jack itself. It is to be understood that this same form of cap may be used on any of the other forms of jacks previously described.

It will be noted that all of these forms of jacks are comparatively small and compact when in lowered position so that they may be stored in a small space, and may easily be inserted for operation beneath very low-lying parts. At the same time the jacks have an extraordinary long lift, and are easily operated by continuous rotary movement of the handle in one direction, through reduction gearing which makes the turning efi'ort light, even when handling heavy loads.

I claim:

1. A lifting jack comprising a hollow standard, a stationary nut in the upper end of the standard, a pair of screws each of substantially the same height as the stand.- ard, and adapted to nest within one another and within the standard, the outer screw being in the form of a sleeve exteriorly threaded to mesh with the nut, and interiorly threaded at its upper end to mesh with the inner screw, there remaining an annular space between the screws below their threaded connection, means for rotating the outer screw, and means having sliding engagement with the standard and inner screw for holding this screw against rotation, but allowing it to move vertically, this holding means being housed within the annular space between the screws when they are lowered to nested position.

2. A lifting jack comprising a hollow standard, a stationary nut in the upper end of the standard, a pairof screws each of substantially the same height as the standard, and adapted to nest within one another and within the standard, the outer screw being in the form of ,a sleeve exteriorly threaded to mesh with the nut, and interiorly threaded at its upper end to mesh with the inner screw, means for rotating the outer screw, a tubular member positioned between the inner and outer screws, and pin and slot connections between the tubular member and the standard and inner screw, whereby these members are all vertically movable with respect to one another but no relative rotation is permitted between the inner screw and the standard.

3. A lifting jack I comprising a hollow standard, a stationary nut in the upper end of the standard, a pair of screws each of substantially the same height as the standard, and adapted to nest within one another and within the standard, the outer screw being in the form of a sleeve exteriorly threaded to mesh with the nut, and interiorly threaded at its upper end to mesh slot, and a projection on the lower end of with the inner screw,- means for rotating the the tubular member movable ina vertical outer screw, and a tubular member posislot in the standard, whereby the tube and tioned between the inner and outer screws inner screw are vertically movable with reand provided with a longitudinally extendspect to the standard and each other, but ing slot, there being a projection on the none of these parts can rotate.

lower end of the inner screw movable in the GUNNAR JENSEN.

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