US2096050A - Lifting jack - Google Patents

Description

2 Sheets-Sheet l Oct. A19, 1937. M, 5 LUCKER LIFTING JACK Filed June 25, 1954 M. B. LucKER Oct. 19, 1937.

LIFTING JACK 2 Sheets--Sheecl 2 Filed June 25, 1954 Patented' Oct. 19, 1,937

LIFTING JACK Millard B. Lucker, Benton Harbor, Mich., assignor to Auto Specialties Mfg. Co.,

St. Joseph, Mich.,

a corporation of California Application June 25, 1934, Serial No. 732,197

14 Claims.

This invention relates to lifting jacks of the screw type, and more particularly to the several lifting parts and to improved methods for producing them and assembling them into position.

It is an object of the invention to providel an economical and readily operable method for form ing the lifting parts of a liftingY jack and for assembling them into operative relation and position.

It is a further object of the invention to provide a method for forming a` thread stop on a screw of a lifting jack which may be readily carried out by a cold forging operation, no drilling or fitting of parts being required.

It is a further object of the invention to provide a thread stop on a screw which is. positive in action, which is strong and durable, which will not jam or lock, and which has no projections tending to cut or scratch the surface with which u the screw engages.

1t is a further object of the invention to provide in a lifting jack means for securing a lifting screw to its operating gearin non-separable relation merely by the inter-fitting of the parts without 1 heading over or deforming them during assembly,

but separation of the parts being readily permitted by a predetermined manipulation of them.

It is a further object to produce an attachment lug on a lifting screw by a single cold forging operation, the lug which is produced being uniform and rugged so as not to be easily broken.

Other objects and advantages of the invention will appear from the following description. taken in connection with the accompanying drawings,

ssiwherein certain preferred embodiments of the inlifting screws in extended condition.

Fig. 3 is a sectional View through the assembly of Fig. l taken on the line 3-3 thereof.

Fig. l is a perspective view of the inner solid lifting screw` which embodies certain features of the invention.

Figs. 5, 6, and '7 are Views of the die blocks used for forming the attachment lug at the lower end of the screw.

Figs. 8, 9, 10, 11, and 12 are views showing the several steps of assemblngthe jack parts.

Figs. 13, 14, and 15 are views showing the deformed thread stop at the upper end of the inner screw.

Figs. 16 and 1'7 are views of the die blocks used for producing a deformed thread stop, and

Fig. 18 is aplan View of the screw driving gear showing more particularly the opening in the center of the gear through which the attachment lug on the screw extends.

While the invention is shown for purposesof illustration applied to an extensible lifting jack of the type commonly used for raising automotive vehicles, it is to be understood that the invention is equally applicable to other types of screw jacks or equivalent devices.

In Figs. l and 2 there is shown an extensible bottom drive lifting jack of the general type disclosed in my prior patent, Reissue Patent No. 17,527, dated December 17, 1929; As shown, av generally cylindrical elongated casting l0 hasV formed in the bottom portion thereof a bearing for receiving a rotatable shaft ll towhich there is secured at the inner end and within the casting, a driving pinion i2. To the other end of the shaft ll there is secured a member having Ya squared socket lll adapted to receive a suitable handle by which the shaft and the pinion l2 may be rotated to extend the jack. Secured to the bottom of the casting li in a suitable manner is a base cap member It, upon which there is-supported a rotatable gear Viii in engagement with and vadapted to be rotated by pinion l2. The gear i8 is centered with respect to cap member l@ by means of an upstanding circular ridge i9 formed on the cap member which engages the under side Aof the bevelled flange of the gear, as shown particularly in Fig. 1.

The inner or small solid screw 2l of the jack is carried upon the gear IB and is secured there. to and constrained for rotation therewith by means of an attachment lug consisting of a generally rectangular or oblong extension 23, extending axially from theV lower end thereof through a similarlyv shaped opening, best shown in Fig. 18, formed in the central part of the gear, and a projection 24', formed angularly at the end of the extension. The attachment lug co-operates with pinion I2 andan inwardly struck projection 2B formed iny casting member l0 to hold screw 2l and the gear I8 in non-separable relation, as will be more particularly pointed out hereinafter. Screw 2| is threaded throughout its length, the threads at the upper end of the screw being deformed to form a thread stop. Y

The threads of screw 2 l engage threads formed In forming thejattachment lug, Athe threaded therewith. In the instance .shown a.taper pin ZSarranged between the'threads is used; The external thread on the screwsleeve 28 Vco-operi- -ates with the thread forned internally on the internally onr thelower upset orY thickened end of anintermediate lscrew'sleeve 28. The screwsleevev 28 is threaded'externally throughout its length, the external threads at the upper end of the sleeve having some suitable thread stop arranged lower upset or thickened end on an outer or large threadedsleeve member 38. YAt theV upper end Vof sleeve3llA is secured a cap 3| which is adapted to engage the object to be lifted by'mega-ek;VV The cap memberl may besuitablysecured to sleeve 30Yby heading over a'flange on thecap intov I an annular. recess 32 cut in :the 'upper end of"V sleeve 30. Sleeve 304 is notextern-ally threaded,

Y Y casting l0, to prevent withdrawal but has at its lower extremity a radially extending' projection 34 which'slides withinY an elongatedr channel 35 running substantially throughout the length of a non-threadedrsleeve member 31, which embraces'sleeve 30; Channel 35 is struck inwardly'at its upper end, as indicated at 38, Fig. 2, Vto prevent'the withdrawal of vprojection'34 upwardly Afrom the channel.V Chan- Y nel 35f`ts within andfslides longitudinally offa co-operating channel Y 40, Vformed longitudinally substantially throughout the length of AcastingY member l0. Channel 35 is formedawith Yan out-.V wardly struck portion 4I at its lower end 'which Y co-'operates with an inwardly projecting portion 42 Aformed at the upper endrofV the channel 48 in Wardly from casting l0. Y 1

The Vpresent inventionV relatesV particularly Vto gear I8 and screws 27| and128,`and tothe method for forming andsecuring these parts.4

Screwr2| maybe VformedrfromY a piece of cyf .lindric-al metalbar stock cut to desired length,V

and threaded throughout its entire length. j The attachment lug formed at the lower jend ofthe screw, and theVV several deformedthreads Aform-V -ing a thread'stopat its upper end are Well shownV in Fig.Y 4, a perspectiverview of the entire screw. f f The dieblocks for forming the attachment lug 1 Vthe means of -attachment of the screw to the gear Y the blocks taken-substantially on the line-55 ,ofV

-Fig. ,6. Lower Ydie block 42 has running from oneV Y, endV thereofa semifcylindrical groove` 43v terrni' hating in a verticalwall portion 44 in the planerV Y of the stepped up portion .42 of the die blockp' a horizontal face portion 45, an angular portion I8 are shownY infFigs. 5, 6, and?. "Fig."1.i`s a perspective view vof.` the lower die block v'42.' Fig. 6 is a longitudinal section Ythrough both dieV blocks, VandFig. 5 is a transverse section through 46, and a second vertical wall portion 41. VVDie Vfaces 45,546 and 41gareV bounded laterally by a pair of vertical walls 48, forming'a continuation Vofthe semiecylindrical groove 43. 'Y Y .Upperdie'blo'ck 5B has a semi-cylindricalgroove' Y `5l running the length thereof Vadapted tomate' with groove 43and lower die block 42,' a steppedf up portion co-operating with Ylowerndie steppedY Vup portion 42', andgardepending projection 52 Ywhich isy adaptedV to extend downwardly between screw is placed s with its lower' end abutting the verticalwall41: Vof the lower die block. The dies are then brought together forming theentire attachment lug by the vertical side g-wallsV 48 Voffthe lower die block*VV towardbut not in contactwilth yhorizontal -rrdie facef45.V

between the separatedV die'blocks Y ence toY Figs. 13 to 177, inclusive. are views taken from the side and top, respectiveof sleeve V31 ups of and substantially at :right at the lower end of Athe screw whichY constitutes i screw threads.` n j vformed. The topV portions threads being too wide to co-operate with the vinsingle operation. 'This .operation is exceedingly simple', only one operation ofjthe dies being required,A and. by the Yoperation a uniform and subv stantial lug is formed. The forging operation maybe performed'without heating the metaland,l

accordingly; thereis no; danger of destroying its tensilev strength by overheating.

The means for forming the threadst'opat the Y upperend. of the screw is best described by refer;

l'y, of Figi` .of the upper deformed *threadY portion of 4the screw, Fig. 13 is a View similar to Fig. 15

,but showing the. deformedv or mutilated screw thread inrran intermediate process of formation, and Figs. liand 1'1are views of the die-blocks Y f forforming the deformed threads.

f The upper'ahd lower die blocks 54 are in this instancesimilar, each having'a longitudinally ex 'Y tending semi-cylindrical groove 56 running from one VVend substantially the length thereof and terminating near the other one end ofthe block Figs. 14 Yand 15 in a vertical wall portion' 51 inthe plane ofV a.'

vertically kstepped downportion 55 formed in"V the face of the` die.' portions 55, the faces willV be separated, as shown Yin Fig. 16, when the die blocks are broughttogether.. i

In forming the deformed or mutilated threads,

Due to the stepped down 4*the threaded screw 2| isplaced betweenithe separated die blocks with its upper end in line with the 58 ofthe two die blocks end. faces 59 of the'blocks. TheY dies are theni f.

brought together, which forms on theY screw a pair of substantially'flat inwardly struck parallel; 'Y

walls 68 on the' end of theV screw,y as shown in Fig. 14, theV distance `between Vthe WallsV being thatV 58 ofthe dies whenthe dies Y are in closed or operated position. The threads,v

between the faces will be mashed substantially smooth Von the faces- After the initial forgingoperation the dies areV separated Aand thee screw Vis fromV the end faces body lies Wholly within the longitudinal'grooves 53.Y During thisY withdrawal rotated through degrees. VThe Vdies areY then brought togethera second time.

formed threads of thefscrew Which were struckV Y During `this forging operation the top 'portions l2rof the .de-j

Y alongv the faces 58 of the die. yblock so thatthe threads remaining on 'the ends;

pulled rearwardly f 590i Vthe die blocks until its j 'of the screwit isv 55 outwardly along thefaces 58Vof the'die during' the first forgingoperation areY againy flattened e .into their original semi-cylindrical contour being.'

thereby thickened; V-The `bottom portions V62 ofV these threads, however,.aresubstantially undisl n turbed during this operation. The final screw threads formed therefore,are asshown in Fig. 15, having their top portions 62 Ywidened. butlying 62'V struck outwardly with respect to porrespond-- ing bottom screwV portions -A double "thread stop is thus 62 vof the deformed ternal thread on sleeve28, and the bottomlfthrea'd portions 62 of the deformed threads being struck 63 of the u'ndeformedf` in the plane ofthe top portions 63 of the uncle-fVV formed 'screwY threads, and their bottom portions outwardly from the axis of the screw so that they will likewise not co-operate with the internal thread of sleeve 28.

This method of forming a thread stop is exceedingly simple and may be very readily carried out. Only one pair of dies is required and the operation is therefore substantially a single one, although two die movements are necessary. The operation may be carried out without heating so that' the tensile strength of the screw is not destroyed, and there is no machining, drilling, or fitting of separable parts.

Sleeve 28 may be formed by upsetting or thickening its lower end portion in any suitable manner, after which the internal threads are cut on the thickened portion and the external threads are cut throughout the length of the sleeve. After the threads are cut, the outer threads at the top of the sleever are fitted with a'suitable thread stop. As indicated in Figs. 1 and 2, in this instance a tapered pin 29 fitted into the wall of the sleeve and arranged between the threads is used but other equivalent stop means could be provided; or the threads at the upper end of screw sleeve 28 could be deformed to form the thread stop as in the case with screw 2|, similar forging dies of larger size being used, and the sequence of operations being the same. However, if the threads were so deformed a center piece of hard metal should be inserted into the sleeve to preserve its interior cylindrical surface during the thread forging operations, so that screw 2| could fit within the upper end of the sleeve so as not to sacrifice any of the lifting range of the jack.

'I'he manner of assembling the several parts of the jack is best understood by reference tol Figs. 8 to l2, inclusive. The inner or small solid screw 2| threaded throughout its length and having its upper end threads deformed to form the thread stop, as shown in Fig. 8, is first threaded downwardly through the sleeve 28, as shown in Fig. 9, the sleeve 28 being in completed form, having both its inner and outer threads thereon and its upper end being arranged with the thread stop. At the time screw not as yet been forged to form the attachment lug, as will be seen by reference to Fig. 9. This is essential for during the formation of parts 23 and 24 at the lower end of screw 2| by the forging operation thereon, the threads at the lower end of the screw are mutilated so that they could not thereafter be threaded through sleeve 28.

After screw 2| is threaded through sleeve 28 the attachment lug consisting of extension 23 and projection 24 is forged on the lower end of the inner screw, as previously described, and thereafter sleeve 28 carrying the screw 2| may be threaded downwardly through outer large threaded sleeve 30, as indicated in Fig. 10. Non-threaded sleeve 31 may then be dropped into position over sleeve 30, as indicated in Fig. 11, after which cap 3| may be secured to sleeve 38.

Gear I8 is now assembled on the lower end of screw 2|, as indicated in Fig. l1, by rst moving it to the dotted position shown, and thereafter moving it to the position shown in full lines. It will be noted that the angular face 46 of lower die 'block 42, forms an angular portion 24', Figs. 4

and l1, on the projection 24 which allows for the movement of gear I8 to assembled position. Casting I8 is now dropped over the assembly, as shown in Fig. 12, and cap I6 is brought up from below and secured to casting I0, as shown in Figs. 1 and 2, to form the completed jack. It will be noted by 2| is threaded through screw sleeve 28, the lower end of the screw 2| hasV reference to Figs. 1 and 11 that removal of gear I8 from screw 2| is impossible unless the gear is moved angularly with respect to axis of the screw member 2| to its angular dotted line position of Fig. 11. In the completely assembled jack such relative angular movement of gear I8 is prevented by the pinion I2 and the inwardly struck projection 26 of castingV of the gear at diametrically opposite points and hold it in position. The casting and the several sleeves hold the screw 2| upright, thus positively preventing any relatively angular movement between gear |8 and 2|, even though an upward force is applied to screw 2|, as by the turning of the jack upside-downorV otherwise. Accidental separation of gear I8 and screw 2| is thereby positively prevented, however, these parts may be readilyseparated for repair and replacement, and the like, merely by the removal of cap member I6 and a reversal of the assembly operation previously described.

It will be seen that the means for assembling parts I8 and 2| is extremely simple, no heading over or hammering of extension 23 being required'after the gear is placed in position with respect to the screw. The projection-24 being formed by a forging operation, may be made substantial and is thus. definitely superior to a projection of variable and doubtful size or strength which might be put on the end of extension 23 manually with a hammer or the like, during the assembling of the parts.

In operation pinion I2 is rotated to'effect the extension of the jack. The operation of pinion I2 rotates gear I8 meshing therewith, and operation of gear I8 rotates screw 2|. Sleeve 30.v is held from rotation by virtue of the engagement of its extension 34 with channel 35 in sleeve 3'I, and by virtue of the engagement of this channel 35 with the larger channel 48 formed in casting IIJ. Screw 2| is in threaded engagement with sleeve 28, and sleeve 28 is in turnin threaded engagement with sleeve 30. As screw 2| is rotated therefore, and sleeve 30 held from rotation, it will be seen that, due to the threaded engagement of the parts, sleeves 28 and 38 will be extended from screw 2| from the Fig. 1 to the Fig. 2 position of the parts. During this operation sleeve 28 may at times rotate with screw 2l and at times be held non-rotatable with sleeve 30. Ultimately, however, the parts will reach their Fig. 2 position.

The mutilated or deformed threads at the upper end of screw 2| and the stop 29 on sleeve 28 limit the upward movement of the parts. Due to the fact that the thread deformations or mutilations on screw 2| are sharply formed, the mutilated portions have no tendency to wedge or jam with their co-operating threads. The thread stop which is thus formed by the thread mutilation is strong and is positive in action inasmuch as a double stop is formed, one stop being the widened top 62 of the mutilated threads,.and the other stop being the outwardly extending bottom portion 82' of the threads. There is no danger that the deformed portions will be sheared off in use, nor is there any chance that they will come loose. During the second forging operation between dies 54, the top portions B2 of the mutilated threads are positively formed into their original semi-cylindrical contour, and hence they have no tendency to scratch or mutilate the sleeve surfaces with which they co-operate. During operation and regardless of the position to which the jack is moved, gear I8 and I8 whichengage the top f screw 2l are held in non-separable relation; howinthe constructions and steps of formation andV rever, these parts may be readily separated for Y.

repair, replacement cover'lrG. Y e .Y Y ,c e Y Itis obvious that various changes may be made orY the like, upon removal of assembly whichfIhave set out for purposes of l thread stop.

formedoutwardly from'the axis of the screw illustration. My invention,` however, contemplates'the use of equivalentswthroughout, and I therefore Vdo VYnotwish to be limited to the pre- Vcise constructions and method and assembly steps the following claims. Y

AIclaim: YY' Y 'Y 1. V'In a lifting jack, a-Y cylindrical screw,-and a Screw'thread cut therein, the groove portion of the screw thread being deformed .outwardly from the axis of the screw sho-wn .and described, but only asirindicated in V2..A screw comprising a screw body, and a helical thread cut therein, said thread having its top portionV widenedand its groove portion deat one point to form a threadfstop. Y e Y3.*In a.V liftingjack, a lifting screw body, a screwrthrea'd cut substantially along the'length of saidY body and formed at one end witha mutilated portion, said mutilated portion comprising a widened thread top and a 'shallow thread `groove,and a lifting screw sleeve having threaded engagement with 'said first-,mentioned thread.

4. In a lifting jack, a lifting screw formed at one end .with anraxial extension having a pro'-,

l jection thereon having a symmetric lateralY extension Yfrom the screw axis, and an operating` gear for a liftingV screw having .an opening Y through which the extension projects.

5. In a combination with a gear and ashaft operable therewith, meansfor securing the shaft to the gear comprising a hook-like extension on said shaft. adapted to'rextendy axially and laterally from theV shaft through an-opening in the gear, and means for holdingsaid gear, from movement angularlywithrespect to the axisV of the shaft.

` 6. Ina combination with a gear and a shaft' l"operable therewith, means for securing the shaft tothe gear comprising Va hook-like extension on ,"said shaft adapted to. extend axially and laterally from the shaftthrough an opening in` the gear, means for Vholding said Vgear;,from movement angularly with Y'respectfto'the axis of the diametrically opposed relation. Y Y

, 17. VIn a lifting jack,a supporta gear; rotatablyV carriedY by saidV support; a lifting screw carried Eby said gear and hield upright by said support, Vand means for securing the screw to the ,gearfor ro- Vtation therewith comprising a hook-like exten- "sion on the screw adapted to'project through an opening formed in thegear, a projectiononsaid supportengaging'the upper gear face, and a drivingpi'nion for the gear also engaging theupper 'face thereof and held in position bythefsupport,

said projection and said driving pinion'being sub- Y Ystantially.diametrically arranged with'respect to Ysaidgear.- `Y Y '7. Y

at one pointY to form a 8, In a lifting jack,a driving gear, alifting screw, means for'Y securing the-lifting screwV to the driving gear for rotation therewith comprising a hook-like Yextension formedonsaidscrew projectingthrough` an opening in said gearand meansrfor preventing relative movementbetween said gear and screw,v a thread formed onY Y means for preventing relative movement between Vsaidrgea'r and said screw, the threadof said screw prevent axial sepabeingmutilated at one endto ration of said screw and said sleeve.V

at Ythe top andfdecreasing in depth to provide Aa stop.` Y Y Y Y10. m' a lifting jaaa-jin combination with .al housing including a basal portion upon which the.

` said screw, athreadedV sleeve threadedly embrac- Y "ing said screw, said sleeve formingipartg'of the 9. A iifungf jack 'having arotatabiygdriven member and ajthreaded liftingelement, aportion off the thread of said element being widened jack is adapted to rest,'a gear freely' restingjon the upper surface of AtheYbase, a threaded driving element having a freely detachable connection f with said gear and lenclosed in said housing, 'said Y connection being'positioned in operative relationship by said housing. i Y L l '11. In 1a lifting jack, inV combination Vwith a lifting housing having a base, a driving pinion in saidhousing, a .driving gear freely resting on the bottom of Asaid base and meshing with. the teeth of the Ypinion, a driving threaded element having a freely detachable connection with said Y gearand enclosed by said housing,jsaid housing forming means for preventing the detachment of saidjdeta'chable connection when said jack-is inY operation, Y ,Y y

12. In a liftingjack, the combination of a housing, a plurality of threaded lifting screws in Ysaid housing adapted for relative actual move-"Y ment, means for'operating said screwsincluding a gear and means for non-separably securingone of said screws to the gear said Ascrew by. said gear upon rotation of v'said gear and merely by the intertting of a Vpartv Aof said screwto said gear without heading or del forming said screw or gear during assembly,Y said means permitting separationof said screw from said gear by aV predetermined manipulation of lllel'ffl.V Y r ref j y 13. In a lifting jack,rthe' combination of a ing said gear, a plurality ofY relatively movable to permit operation of Y Y Y F50 housing, a gear `m said housing, means for rotat- Y inter-threaded members, one fof Asaid1threaded. l

members havingY Y with-said gear :including means for causing Yrotation of said Y,threaded member by said gear in the normal Ioperation ofthe jack, said housing including Vmeans for preventingVV detachment of' said threaded member from 'said gear during the Ynormal operation of the jack. Y y

14h-In'Y a lifting jack construction, a'drivingV gear, aA lifting screw,Y said gear being rotatable a freely detachable.,connectionV Y rz55 about the Yaxis of the screw'and valso-being bodily e displaceable with respect to the screw axis, means forming aconnection between the gear detachable Yupon Ybodily displacement of the gear with'respect to thescrew axis,Y and means forA holdingthe gear from such bodily displacement MILLARD B. LCKER :'65 and screw whereby said screw 1s rotatably driven Y n as the gear is rotated,said'connection-beingfreely ras the gear and screw are normally mounted in 70 Y the jack construction.

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