US2573877A - Lifting jack construction - Google Patents

Description

L. SCHWEITZER LIFTING JACK CONSTRUCTION Nov 6, 1951 2 SHEETS SHEET 1 Filed Jan. 16, 1950 INVENTOR.

100/5 JCHWf/TZZK 1951 L. SCHWEITZER LIFTING JACK CONSTRUCTION Filed Jan.

, 2 SHEETS-SHEET 2 INVENTOR.

100/5 JCHWf/TZZR BY Qaflk- 4 ATTO/F/Vf J Patented Nov. 6, 1951 FNIiiO"I E w "Y LIFT ING .ifnf'on ooNsTntJorIoNf Louis Schweitzer,- Royal Oak, Mich, assignor to Motor Products Corporation, Detroit,'Mich., a i

corporation'of NewYorks' v Application January 1s, 1950, SerialNoI138,905

This invention relates to lifting jacks and refers more particularlyjto improvementsiin jacks of the type used in' connection with road vehicles for raising a selected ground engaging wheelgf It is an object of this invention to provide a light weight jack capable'of lifting substantial loads with no danger to inexperienced-users and composed of arelativelyfew simple parts capable of being inexpensively manufactured and asse'mbled. f

The simplicity; ease and safety of'operat ion of the jack is due largely to the use of sliding wedge typelocking devices inpl'ace of the usual ratchet or rackand gear typesof lifting mechanisms. In accordance with this invention, at least two wedgetypelocking devices operate-"in conjunction withone'a'nother te elevate the lift and cooperate to securely hold-the lift inany one of its raisedpos'itijons, i

It is afurther object of this invention to provide a jack of the abovetype' wherein the wedge devices are alternatively moved upwardly by an arm to raise the jack lift step by step and'wherein provision is made for releasing the wedge devices to permit lowering of'the'lift without manipulating the'arm." As a 'result, the jack may be lowered'with ease and the danger of'thearm striking the user is avoided. v The foregoing as wellas other objectswill be made more apparent'as thisdescription proceeds especially when considered in connection with the accompanying drawingswhereinz' Figure l'is'a" side elevationalview of a weight lifting "jack embodying the features of this inven- Figure 2 is a longitudinal' -sectional view through the lower portion-of -the-jack;--

" Figure 3 is'an enlarged vertical 'se ctional' -view through a partoffthe jack-shown in Fig-urel;

Figure 4 is a sectional view taken onthe line 4-4 of Figure 2; 1

' Figures 5' and-6 are sectional views taken respectively inthe lines 5-5 and 6-6 of Figure 4.

Figure 7 is a sectional view taken on the line 1- -1'ofFi'gure5 The jack selected herein for the purpose of "illustration is especiallyadapted for the purpose of raising oneor more of the ground engaging wheels of a -road vehicle and the nature-ofthe operating mechanism renders the jack highly suitable for applications wherein a substantial stroke or-movement of the elevating part is required such, for example,=as is the case withsocalled bumper jacks.=

- I The lifting-jack shown in-Figures Land 2 or ape rturedto receive a socket l5. The socket l5 I '8Claims." (Cl. 254-106) is open'at the top and has a-lateral flange 16 which overlaps the top surface of the elevated base portion M.- A slot I1 is formed in one side of the socket I5 and a resilient strip'l8 extends across the slot'at the outer side of the socket. The upper end of the strip is secured in place by the flange [6 and the lower end of the strip crimped around the'bottom-edge of the socket. The resilient strip is bent intermediate the ends to provide aloop l9 which projects into the socket 15throughthe-slot l1.

' The column Ii is also preferably formed of sheet metal and is shown in Figure 4 of the draw ings'as being channel-shaped in cross section. The opposite side walls- 20- and 21 of the-column are provided with laterally inwardly projecting flanges-22 which terminate short of one'another to provide a longitudinally extending slot 23 therebetween; Also, the flanges 22 cooperate-with the remaining portions of the-column to form a-vertically extending guideway 24.

tioned to register with the slot I! and to receive the loop 19 of the resilientstrip la in' the assembled position offthe column with respect to the socket. The loop 19 of the spring lBprovides a resilient detent for removably holding the column ll in'a'vertical position on the base I0." The elevating part I2 is shown in the several figures of the drawingsa's comprising a pairof elongated channel-shaped sections 26 positioned with the channels opening toward one another and of a size to receive the vertical column 20, as shown in Figure 4 of the drawings. The sec,'- tions 26 are secured in assembled relationship by a pad or support 2'! in the form of a sheet metal stamping. The pad 21 is shown in Figures land 2 of the drawings as extending laterally with rel- .spect to the column and as having laterally spaced projections 28 at theinner end. The pro- .J'ections 28 are shown'in Figure-4 of the drawings of a vehicle to lift the same when required.vv The lifting mechanism l3 comprises an operating memberv 23, a :pair of locking devices 30...;and

3i. anda releasing member 32. Thelockin'g devices 36, 3|. are slidably supported. withinlthe guideway 24 and it will be noted'from FiguresZ and 5 of I the drawings that the device 30 is supported in the guideway directly above the device 3l.

The locking device 30 is provided with a pair of wedgesi33and'34 slidably supported one above the other within the guideway 24. The adjacent ends of the wedges are inclined in a direction extending transversely to the guideway .24 and pro vide overlapping surfaces 35 and 36 on there'- spective wedges.

The locking device 3! also comprisesa pair. of wedges3l and 38 slidably supported within the guideway 24 with the wedge 3! positioned above the wedge 38 in vertical alignment with the lat-' ter. 3'! and 38 are inclined with respect to the guideway 24 to provide overlapping suriaoes 39 and 49 on the respective wedges. As shown particularly Figure of the drawings, the'two pairs of wedges are similar inconstruction but are relatively positioned so that the overlappingsurfaces 39 and 48 on the respective wedges 31 and 38 are inclined in a directionopposite the direction ofinclination of the corresponding surfaces on the wede sfi a shown in Figure 7 of the drawings .the opposite ends of the springs 4| areturned laterally and respectively project into elongated slots formed the wedges of each pair 35 and 3|. '1he ;springs 4l merely-serve as ties between the respective wedges inithe pairs 30 and 3| in order permit movement of the wedges in each pair as a unit in an upward direction. The strength 7 of the springs 41 is not sufficient to cause jam- Themtermaiate' portion 43 of 'the'strip' con- 7 tiniies downwardly alongth'e' inner surface of the side Hand is extended betwe'en' the overlapping surfaces '39' and 40 of the wedges 37 and 38. "The lower end 44 of the'strip continues downwardly Talo'ngthe inner "surface of the side 20 to a point adjacent the bottom of the column'wherein it 's'ecuredto'the column. The upper'end of the flexible strip 'extendsfor a substantial distance abovethe'locking device""30 and-"is also-secured to the column. "Attention is called to the factthatthe intermediate portion 43 of the flexible member or strip is notfastenedtotheadjacent side of the guideway-24 and as-a consequence does not inter 'fere with therequired-movement of thewedges. The-purpose of the flexible-member isto hold the wedges in frictionalcontact with the sides of theguideway -24 so that only a slight relative movement of the wedges ofeither locking device towardone anotheris suflicient to cause .jammingof the wedges against adjacent sides of the guideway 24.

The above. arrangement is such that whenthe force is applied in anupward directionlto the wedge 33, the overlapping .or .wedging surface. 35 is moved away from the coacting. surface 36 on the lowermost .wedge34so that both wedges 33 and 34 maybe readily moved in an upward .direction .within the guideway 24. Thisis also true of .the .second pair of wedges of. the locking the adjacent bottom wedges.

4 device 3!, although the two pairs of wedges are independently movable along the column.

Adownward force applied to the uppermost wedge of each paircauses these wedges to move relative to the guideway 24 in a direction toward The slots into which the laterally turned ends of the springs 4| 7 "project are of sufficient size to permit the required movement of the top wedges 33, 31 toward wed'ging'faces 35', 39011 the respective top wedges The adjacent end portions of the wedges 33,31 press against the adjacent portion of the flexible strip 42 and apply a laterally outward force component against the oblique wedging surfaces 36,10 of the bottomiwedges 3.4 an-d38 respectively. Thus the wedges of each pairare shifted laterally outwardly and are jammed against the adjacent sides of the guideway 24. In other words, the .wedges of each pair become frictionally locked against further downward movement relative 'to the guideway'24.

Releasing ofthe wedges may bev readily accomplished by merely applying a downward force on the lowermost wedges of each pair. This application of force moves the lowermost wedges downwardly'slightly relative 'to the uppermost wedges andenables. the .locking'd'evices to be freely moved downwardly'in the guideway 24. This releasing action is accomplishedin the present instance by .manipulating the member 32 which will' be presentlydescribedin detail.

As shown'in Figures 1 to 3inclusive, the wedge 33 is provided with a lateral "outwardly. extending projection 45 and the wedge3l is provided with a similar'projection 4.6. The projections '45 and 46 extend through the slot23 in the column 1i and also respectively project through elongated slots 41 andfi lfo'rmedfin the lifting device 12. The wedges 3'4 and 38 are respectively provided with lugs 49 mate; These lugs alsofextend through the slot 23 the column 'I l and respectively projectthrough s1ots.5l and52 formed in the adjacent wall of "theflifting part l2.

The operatingmember 29 has a socket part 53 shaped at sneienaw slidably receive a suitable tool 54 and having the other endconnected to the projection 45 by pivot pin 46'. in a manner to enable swinging movement ofthe part 53 in a vertical plane. Thesocketpart 53 is also connected to the lug 46 by a lever 55. The upperend of the lever'55 is pivoted to thepart 53 at a point spaced outwardly from the pivotflfi arid the lower end of the lever is pivotedfto the projectionllfi.

The releasing member 32 comprises a plate 56 extending in the direction oflength of the column, and positioned atthe outer?side ofthe elevating-part L2. Asshownpar ularly in Figure 3 .of the drawings, the plate 5Hisprovided with sl ts 51 8 M531 r sp ct v re e ing he p jections. and 46. Also fth eleasing plate is fashioned with slots 59' an Silfor respectively receiving the lugs 49 and Theupper end of the plate has alaterally inwardly extending lug 6| which projects over the 'djacent end of the elevating part l2 so as to be oyedas aunit with thelatter. A suitable operating leme 62 i secured to the releasing pla ;-.56 adjacent the lower end inja Position, to --bec0nvenient1y engagedby afoot of -the user.

' Op r tion Assum n t at th W d e-parts f the jack preyiously descr e are in the tslei iv qsiii e shown in Figure 2 of the drawings, and that it is desired to raise the lifting part l2 relative to the column H, the operator causes the member 29 to be swung downwardly. The resulting force is transferred to the wedge 37 through the lever 55, and since the wedge 37 is locked against downward sliding movement in the guideway 24, the wedge 33 together with the wedge 34 is moved upwardly in the guideway 2 3. Upward movement of the wedge 33 causes the projection 45 to engage the shoulder 63 on the elevating part I! and moves the latter upwardly along the column I'l.

Upon completion of the above, the operator raises the member 29 and as a. result applies a downward force on the wedge 33 and a lifting force on the wedge 31 through the lever 55. Since the wedge 33 is locked against downward movement in the guideway 24, the wedge 31 together with the wedge 38 is moved upwardly along the guideway 24. As shown particularly in Figure 3, upward movement of the wedges 31, 38 causes the projection 46 on the wedge 3! to engage the top wall 64 of the slot 48 in the part l2 and moves the latter upwardly.

It follows from the above that successive movement of the operating member 29 in opposite directions causes the locking devices 36 and 3! to alternately move upwardly with a step by step movement. Inasmuch as the elevating device !2 is moved as a unit with the locking devices, it

' follows that the pad 21 supporting the part to be raised is also elevated.

When it is desired to release the jack, or in other words, lower the elevating device l2, the operator merely applies a downward thrust on the part 62 connected to the plate 56. Slight downward movement of the plate 56 causes the upper walls of the slots 59 and 643 to respectively engage the projections 49 and 5!! on the respective wedges 34 and 38. As a result these wedges are moved downwardly relative to their companion wedges and both locking devices are released permitting the elevating device [2 to slide downwardly along the pedestal l I. the above construction to effect periodical downward movement of the elevating device by merely successively applying a releasing pressure on the part 62. In any case the releasing action does not cause the operating member 29 to kick in either direction and endanger the operator. In fact the operator may release the jack from a safe position with respect to either the jack or the vehicle.

What I claim as my invention is:

1. A lifting jack comprising a base, a column supported at its lower end on the base, an elevating part supported by the column for sliding movement lengthwise of the column, a pair of locking devices supported by the column for vertical sliding movement relative to the column, each locking device comprising a pair of vertically aligned wedges having adjacent overlapping surfaces at the inner sides inclined with respect to the path of sliding movement of the devices, abutment surfaces on the column extending vertically in the direction of sliding movement of the locking devices and respectively engageable with the outer sides of the wedges, means connecting the wedges of each pair permitting limited relative sliding movement of the wedges, an

It is possible with operating member respectively connected to the uppermost wedge of each pair for alternatively moving the locking devices upwardly relative to the column, and means on the elevating part respectively engageable by the uppermost wedges of each pair to impart a lifting movement to said part.

2. The lifting jack set forth in claim 1 in which a releasing member is respectively connected to the lowermost wedge of each pair for releasing the wedges and permit lowering of the elevating part.

3. The lifting jack set forth in claim 1 in which the wedges of each pair are connected by a spring element, and in which a flexible strip extends between the overlapping wedge surfaces of each pair of wedge and has end portions which project beyond the locking devices between the abutment surfaces and the adjacent outer sides of the wedges.

4. The lifting jack set forth in claim 1 in which the column has a vertically extending channelshaped guide, and in which the locking devices are slidably supported in the guide one above the other.

5. The lifting jack set forth in claim 4 in which a thin flexible strip has the opposite end portions respectively ecured to one side of the channel beyond the locking devices and has an intermediate portion respectively extending between the overlapping wedge surfaces of each pair of wedges to the opposite side of the channel guide.

6. A lifting jack comprising a base, a column supported at its lower end on the base and havin a vertically extending channel-shaped guide, a pair of locking devices supported in the guide one above the other and slidable along the guide relative to the column, each locking device comprising a pair of vertically aligned wedges having adjacent overlapping surfaces at the inner sides inclined in a direction extending transversely of the guide, spring means respectively connecting the wedges of each pair, an operat ing member having one end portion pivoted to the uppermost wedge of the top locking device for swinging movement in a vertical plane, a lever having one end pivotally connected to the uppermost wedge of the bottom locking device and having the other end portion pivoted to the operating member at'a point spaced from the pivoted end of said member whereby swinging movement of the member in opposite directions alternatively moves the locking devices upwardly along the guide, and an elevating part supported by the column and connected to the locking devices for operation by the latter.

7. The lifting jack set forth in claim 6 having a member supported by the column for sliding movement relative thereto and having portions respectively engageable with the lowermost wedges of each pair for releasing said wedges.

8. The lifting jack set forth in claim '7 having a thin flexible strip extending between the overlapping surfaces of the wedges of each pair and having end portions secured to the column beyond the locking devices to permit movement of the devices along the guide.

LOUIS SCHWEITZER.

No references cited.

Images