US2469048A - Lifting mechanism - Google Patents

Description

May 3, 1949.

R. F. MANKE LIFTING MECHANISM .Filed June 241946 IN VEN TOR.

2 Sheets-Sheet l May 3, 1949. R. F. MANKE 2,469,048

` LIFTING MEQHANISM Filed June 24, 1946 2 Sheets-Sheet 2 Patented May 3, 1949 lm'lrlNT QFFICI.

LIFTING MECIIANISM Raymond F. Marike, Racine, Wis.,

Walker Manufacturing Company or Racine, Wis., a corpora Application .lune 24, i946, Serial No. 678,917

(Cl. .2M-126) 21 Claims.

The present invention relates to lifting devices, and is particularly directed to the provision or" improved jack constructions which may readily be pulled or pushed over a surface, such as rough ground, pavement or the like, to a desired position eneath a load, such as an automobile, to be lifted. The principal objects of the invention are to provide improved jacking means of the above generally indicated type which is simple in construction and arrangement, economical to manufacture and assemble, and reliable and efficient in operation; to provide such construction employing a lifting arm of the cantilever type, and embodying improved means for effecting elevating movement' of such lifting arm, such means including camming mechanism which is effective throughout at least the initial portion of the lifting movement; to provide such construction wherein the camining means is carried in part by the lifting arm and in part by the primary forceapplying means; to provide such construction wherein the primary force-applying means cornprises a pair of relatively movable elements, one whereof is adapted for continuous connection to the lifting arm, and the other whereof is adapted to have a camming connection to the lifting arm throughout a portion of the movement of the latter; to provide such construction wherein during the course of the camming action, the primary force-applying member is bodily movable while in addition relative movement occurs between other elements, the bodily movement being effective to reduce the torque which must be applied to the force-applying member; to provide such construction wherein at the conclusion of the cammlng action, the camming element of the force- `aimlying member becomes anchored; and to generally improve and simplify the construction and arrangement of lifting devices of the above generally indicated types.

Tfith above as well as other and more detailed objects in View, which appear inthe following description and in the appended claims, preferred embodiments of the invention are shown in the accompanying drawings, throughout the several views of which corresponding reference characters are used to designate corresponding reference characters are used to designaL corresponding parts and in which:

l view in side elevation of a floor ,jack embodying the invention;

Il. is a view in vertical section, taken line lA--lA of Fig. 1;

plan view of the structure of Fig. l;

assigner to Wisconsin, tion of Wisconsin Figs. 3 and 4 are sectional views taken substantially on the lines 3-3 and 4 4 of Fig. 1;

Fig. 5 is a view corresponding to Fig. l, but showing the lifting arm in various elevated positions;

Fig. 6 is a sectional detail taken substantially on the line of Fig. 5;

Figs. 'l and 8 are, respectively, views in longitudinal central section and in plan of amodication of the invention; and,

F'g. 9 is an end view of the modified form.

t will be appreciated from a complete underof the present invention that the improvements thereof may be embodied in various different forms, and in lifting devices specifically adapted for a wide variety of different purposes. Preferred applications of the invention are in connection with so-called floor jacks of the vertical lift cantilever type and, by way of ill-,ustration but not of limitation, the invention is so disclosed herein.

Referring nrst to the embodiment of Figs. 1 through 6, the illustrated floor jack comprises generally 9, frame or base I0, adapted to rest upon a supporting surface, and a lever-type lifting arm l2, which carri-es a work-engaging head I4. Arm l2 is movable between thel fully retracted or collapsed position of Fig. l, and an elevated position corresponding to the position shown in dotclesh lines in Fig. 5.

In the illustrated instance, the skid-type base lli is of upwardly opening channel form and may he formed, for example, of relatively heavy gauge sheet metal, which may be cold formed from flat stock into the indicated channel form. The forward end la of the frame is formed as a prow,

` which makes it possible to place the jack under the car on rough or soft ground such as gravel or black-top.

The marginal edges of the flanges ma, of the frame are inwardly turned as indicated at Illb, to guide the reduced ends 26 of the driving traveler nut it. rlhe ends of the central body portion of the nut I3 are pivotally received in openings provided therefor in flanges lia of the lifting arm. Retaining washers 22 held in place by pins hold the nut IS against axial movement it being noted that the washers 22 lie between the flanges l2a and Illa. At its lower end, the cross web of the lifting arm l2 is cut away as indicated at i219 to provide clearance for the screw en the jack is fully extended (Fig. 5). The 2li of the traveler nut i3 bear against the underside of the rails constituted by the base `flanges illb. Such engagement limits upward to slide along the bottom web Ille preferably of hard material, as by welding, to the bottom, correspondingly movement of the lower end of the arm I2 relative to the base. A corresponding limi-t to downward movement of the lower end of the arm I2 relative to the base is aorded by the underside portions 28 of the previously mentioned extreme end portions of the arm flanges I2a, portions 28 lying immediately adjacent the bottom cross web Ic of the base I8. The screw shaft 3i? is thus relieved of transverse loading.

The driving nut I8 thus provides a pivotal connection between the lifting arm I2 and the base I8, which pivotal connection is bodily movable lengthwise of the base I8 from the lowered position shown in Fig. 1 to the elevated position shown in Fig. 5, under the influence of the driving screw 35.

A pair of radius arms 32 are positioned at respectively opposite sides of the lifting arm I2. Arms 32 are each pivotally connected at one end to an intermediate portion of the lifting arm I2 by a pin 34, which is rotatably received in a sleeve 33, which is fixed to and extends across the lifting arm I2. The lower ends of the arms 32 are similarly pivotally connected to the base IU by a pin 38, which extends across and is supported by the side flanges Ifla of the base I8.

The lifting head I4 is of downwardly opening channel form. A pin 48, which extends across and positions the head, is rotatably supported in bearing openings provided therefor at the outer ends of the side flanges I2cJ of the lifting arm I2. A pair of stabilizing links 42 are also pivotally connected between the head lil and the arms 32. More particularly, one end of each stabilizing link 42 is pivotally connected to the corresponding arm 32, by a pin 44, and the other end thereof is pivotally connected to the head I4 by a pin 46. It will be recognized that the purpose of the stabilizing link 42 is to maintain the upper or work-engaging surface of the head I4 in a substantially horizontal position throughout the lifting and lowering movement of the arm I2, the

location of pin 44 being so selected as to achieve such action.

The previously mentioned driving screw 30, which is provided with a rotary driving head 50 (having a squared handle receiving aperture 50a) at its outer end, is conventionally threaded through the driving nut I8. The inner end of the driving screw passes freely through an open ing 52 provided therefor in the wedging slide 54. At `its extreme inner end, screw 38 is provided with a ball bearing assembly 56, the outer race 58 whereof is fast on the screw, and the inner race G8 whereof bears against a vertical bearing surface 62 provided upon the face of the slide 54. Slide 54 is provided with a flat bottom adapted of the base I0. Withdrawal of the slide 54 from the base I0 in a vertical direction is prevented by the base flanges Illb, which overlie the laterally projecting portions 55 of the slide. At a point somewhat spaced above the base I8, the slide 54 is provided with a pair of wedging or camming rollers 10, which are mounted on a transverse trunnion shaft 'I2 carried by the slide. Throughout the initial portions of the lifting movement of arm I2, rollers 'I0 have camming engagement with a pair of curved cam surfaces lll, carried by the underside of the lifting arm I2. As shown, surfaces 'I4 are formed by curved angle sections, which are secured,

curved, edge portions of flanges I2a. It will be appreciated that the particular curvature which is given to the camming surfaces I4 is one which tends to make the lifting effort more uniform.

It will be appreciated that wedging slide 54 is bodily movable Within the base I0. The limit of such movement is encountered at the conclusion of the hereinafter described camming action. As shown, this limit is afforded by stop links 16, which are secured within the base channel by the same pin 38 which serves as the lower pivot for links 32. Links 'I6 are formed of sheet meta-l and lie against the inner faces of the side anges Ia of the base, and are provided with inturned ends 'i8 which project into the path of and limit the travel of the slide 54.

It is believed that any remaining details of the structure of Figs. l through 6 may best be understood from a description of the operation thereof. As previously mentioned, the parts are shown in Fig. 1 in the retracted or collapsed positions thereof, in which the arm I2 occupies a substan tially horizontal position, and in which the overall height of the jack is very low. To effect an elevating movement of arm I2, screw 3l] may be rotated in a direction to cause driving nut I8 and slide 54 to approach each other. Slide 54 moves to the right as vieWed in Fig. 1. Since slide 54 is free to move lengthwise of base Ill, the turning of the screw causes a rightward movement of both the slide and screw, during the course of which the rollers 'I0 ride along the undersides of the cam surfaces I4 and force them and arm I2 upwardly. The lifting movement of arm I2, as influenced by the slide 54, also elevates the arms 32, rocking them about the xed pivot 38. Such lifting of links 32 requires the nut I8 to move to the left. So long as slide 54 is free to move length- Wise of the base accordingly, revolution of the lifting screw 30 causes bodily movements of both the slide 54 and the driving nut I8. Such revolution of the driving screw accordingly causes less movement of driving nut I8 than would be the case if slide 54 were fixed. Since the rate of rise of the head I4 is proportional to the rate of angular displacement of the pivot points repre sented by nut I8 and pin 34, it will be appreciated that, during the movement of slide 54, the head I4 rises at a reduced rate for any given rate of screw movement, thereby requiring a correspondingly decreased turning force on screw 38. The degree of reduction, of course, depends upon the slope of the cam surfaces 14, which, as stated above, are preferably curved.

When slide 54 encounters stop lugs 18, further rightward movement of the slide is prevented. Thereafter, rotation of the screw 3U causes the driving nut I8 to advance an amount equal to the lead of the thread on screw 30 and, for a given rate of screw movement the leftward movement of the end of arm I2 proceeds at a correspondingly accelerated rate. Since the arm I2 is approaching the vertical, however, the actual rate of upward movement of the head I4 may be somewhat reduced.

It will be appreciated that when the lever arm I2 is in its collapsed position, only a small component of the actuating force, acting lengthwise of the base and applied to nut I8 by screw 30, acts in a direction at right angles to the lifting lever I2, to exert lifting effort upon the load by tending to rock the lifting lever about its fulcrum pin 34. As the arm I21is raised, however, such component is progressively increased. Accordingly, it is preferred to maintain the camming action in effect until the 'arm I2 has risen to such height that the just-mentioned component is of a desired magnitude. In Fig. 5, the arm I2 is vmovement of slide 54.

shown fin an intermediate position, at which slide Ell has just encountered the stops 18, and .at

which, accordingly, the rcamming action is about to terminate. In this position, the lever arm, `delned by a line connecting ulcrum with power-.applying lpins 2li, is at a 'substantial angle Vrelative to the direction (horizontal) of applied force, fand .con .ently the just-mentioned com-- ponen-t is of ,a desirably substantial gnitude.

In .lowering the jack, a reverse action or course takes place. That is to until such time as the cam surfaces 14 encounter the slide 54, the latter remains stationary, and nut I8 takes up ,full screw movement. When the surfaces 14 encounter the rollers of the slide, continuing `downward movement of the arm l2 requires a leftward .movement of the slide and screw.

In order to lguide the lifting arm and base .as they close upon one another in lowering, the wedging slide 54 is preferably provided with an upwardly projecting top 64, pointed as viewed in end elevation. Thus, even if the parte are transversely sprung, within certain limits, as by being heavily loaded while the jack is resting upon a laterally inclined surface, they are again guided into proper relationship as the load is lowered.

It will be ynoted that in the Vembodiment oi Figs. 1 through Y6, the screw 3!) moves outwardly of the lbase kIt! (to the right, as viewed in Fig. l) `during the initial stages of the elevating movement, to accommodate the above described In the embodiment of Figs. 7., 8 and 9. a reverse relation obtains. That is to say, in the embodiment shown in these gures, the screw moves inwardly of the base (to .the right, as viewed in Figs. 'l and 8) during the initial or camming stages of the elevating movement. In Figs. 7, 8 and 9, the base 88 is of upwardly opening channel form, as before, and provided with a downwardly opening channeled lever-type lifting arm 82. Arm 82 is provided at its lower end with a reaction member 84, which serves to pivotally connect the arm 82 to base 8|). Member 8L!- is supported by rollers which are adapted to roll along the underside of the base flanges Sua.. The pivotal mounting of arm 82 will be seen to correspond to the similar bodily movable support of the previously described embodiment.

The screw 8B passes through an opening provided therefor in the reaction member Sli. Screw 88 is freely rotatable within such opening. but is fixed against longitudinal movement relative to the member 8d. For this purpose, screw $8 is provided with an enlarged head. or shoulder 90 which bears against the outer face of the reaction member 84. If desired, a roller bearing assembly or other anti-:friction means may, of course, be interposed between shoulder 98 and the reaction member 84. The inner end of the screw 88 is received in a driving nut 92, which is provided with rollers 94, adapted to roll along the underside of the flanges 88a of the base 88.

To limit the leftward movement of the driving nut 92, as viewed in Figs. '7 and 8, the base ilil provided with stop members 96 which correspond to the previously described stops lli, and may be secured to the inner opposite sides of the base.

The connection between the lifting arm 82 and the base 8l!I is completed by a pair of radius arms 9.8, which correspond to previously described arms 32. The upper ends of these links are pivotally connected `to the lifting arm as indicated at faces of the respectively lifted, a

1"Illll, Iandthe lower ends thereof 'are'.pivotally connected to the base, as indicated at 1:82, Athe last mentioned pivotal connection being fixed in position relative .to the 4base. It will be appreciated that a lifting head and stabilizing rarm. may ibe utilized in connection with the arm 82, suc'h elements having been omitted from the drawing to simplify it.

As to operation (the parts occupy their foollapsed positioning in Figs, 7 and 8), to effect a lifting movement, the crank |88 which may be conventionally and releasably `connected to the screw 88, at the outer end thereof, may be rotated in a. direction to cause the driving nut 92 and the reaction member 84 to approach each other. As in the previous embodiment, this relative movement between the reaction member and the driving nut produces a pivotal Ymovement lof the lifting varm 82 about the axis Yof the reaction member 84. Such pivotal :movement in turn, vbv virtue of the arrangement of the lifting links 98, requires a, rightward movement of the reaction member 84. The driving nut 92 moves to the left as rollers gl, acting upon cam `lportions 95, raise the lifting lever 82. Consequently, the relative movement between members 84 and 92 involves a combination of rightward movement of reaction member 84 and of leftward movement of the driving nut 92. The relative rates of these two movements, zand consequently the extent of movement of head |84, per revolution of the screw yB8, is of course determined by the slope 'of the cam surfaces S5 on the arm 82. When the driving nut 92 encounters the stop-shoulders 96, further leftward movement :of the nut is prevented and the continued rotation of the screw drives reaction member 84 to the right, elevating the arm 82 to its fully projected position. The lowering movements are effected in the reverse manner as vdescribed in connection with the previous embodiment.

Although only certain specific embodiments of the invention have been described in detail., it will be appreciated that various further modications in the form, number and arrangement `of parts may be made without departing from the scope of the invention.

I claim:

l. A lifting jack comprising a support, a lifting lever mounted upon said support for bodily movement relative to said support and having end portion adapted to engage a load to be reactive force member operatively connected to said lever intermediate the ends `of d lever. means for applying power to the other engi of said lever to rock the same about said force member, cam means bodily movable substantially longitudinally relative to said support 'for applying a powerful wedging action to said transversely between said ends to rock 'the ve about said other end, and stop means limitmovement 'of 4said cam means whereby said last named means is `effective solely during initial movement of lever.

2. Means as set forth in claim 1 in which said support comprises van elongated'base, said means comprising an actuating portion movable substantially longitudinally with respect to the base, guiding means con-trolling movement E other end of the lever and restricting such rent to a predetermined path, 'said cam mens power-applying means having a common vactuating means carried by the base for moving said other end 'and said `actuating porti-on tow-ard and from one another.

3. Means as set forth in claim 1 in which said support comprises an elongated base, guiding means controlling movement of said other end of the lever and restricting such movement to a predetermined path, said cam means and power-applying means having a common actuating means carried by the base for moving said other end and said cam means toward and from one another.

4. Means as set forth in claim 1 in which said support comprises an elongated base, guiding means controlling movement of said other end of the lever and restricting such movement to a predetermined path, said cam means and power-applying means having a common actuating means reacting in opposite directions against said other end and said cam means, and said actuating means including floating power-applying means for equalizing the actuating effort applied to said other end and to said cam means.

5. Means as set forth in claim 1 in which said support comprises an elongated base, guiding means controlling movement of said other end of the lever and restricting such movement to a predetermined path, said cam means and powerapplying means having a common actuating means reacting in opposite directions against said other end and said cam means along a line substantially parallel to the base, and said actuating means including floating power-applying means freely movable in either direction along said line to equalize the actuating effort applied to said other end and to said cam means, said cam means being profiled to vary the component of such actuating eiTort which it transmits to the load-engaging end during` actuation.

6. Means as set forth in claim 1 in which said support comprises an elongated base, guiding means controlling movement of said other end of the lever` and restricting such movement to a predetermined path, said cam means and power-applying means having a common actuating means reacting in opposite directions against said other end and said cam means, and said actuating means including floating power-applying means for equalizing the actuating effort applied to said other end and to said cam means, said cam means being profiled to transmit a larger component of the actuating eiiort to the load-engaging end than is transmitted thereto from said other end, at least in certain angular positions of the lifting lever, whereby said common actuating means rst moves said lever through the cam means and then moves said lever through the reactive force against said force member during a load-lifting actuation of said lever.

7. Means as set forth in claim 1 in which said cam means and said means for applying power to said other end of the lever are actuated -by a single screw reacting against both said other end and against said cam means.

8. Means as set forth in claim 1 in which said cam means and said means for applying power to said other end of the lever are actuated by a single screw reacting against both said other end and against said cam means and tending to move them toward and from one another, said screw being bodily movable longitudinally to equalize the driving component applied to both.

9. Means as set forth in claim 1 in which said support comprises an elongated base, common actuating means for said cam means and said other end comprising a screw movable longitudinally of the base and reacting against both said cam means and said other end.

10. Means as set forth in claim 1 in which said. support comprises an elongated base, common actuating means for said cam means and said other end comprising a screw also movable longitudinally of the base and reacting against said cam means and said other end, said reactive member coacting with said camming means to control bodily movement of said lever relative to said base.

11. Means as set forth in claim 10 in which guiding means restricts movement of said other end to a predetermined path with respect to the base.

12. Means as set forth in claim 11 in which a travel nut is actuable by the screw to actuate said other end of the lever, and means is provided to limit travel of the screw with respect to the camming means.

13. A lifting jack construction comprising, in combination with a frame, lifting lever means including a load-supporting arm, a bodily movable ulcrum portion intermediate the ends of said lever means, cam means bodily movable along said frame for bodily moving said fulcrum portion, and common power-applying means acting laterally in one direction against said cam means and laterally in the opposite direction against one end of said lever and tending to rock the lever about both said fulcrum portion and said one end, whereby a load upon said load-supporting arm may be raised by said lever means acting both as a first-class and third-class lever.

14. A lifting jack construction comprising, in combination with a frame, lifting lever means nciuding a load-supporting arm, a bodily movable fulcrum portion intermediate the ends of said lever means, cam means bodily movable longitudinally of said frame for bodily moving said fulcrum portion, common power-applying means comprising means for simultaneously moving said cam means and one end of the lever towardone another, said cam means including a cam portion so shaped that the fulcrum portion is thereby moved away from a line connecting said cam means and said one end of the lever, said common power-applying means acting laterally in one direction against said fulcrum portion and laterally in the opposite direction against said one end of said lever and tending to rock the lever about both said fulcrum portion and said one end, whereby a load upon said load-supporting arm may be raised by said lever means acting both as a first-class and third-class lever.

15. In a lifting jack of the type in which there is a base support member, a guide member movable along said base member and held thereby for movement in a, predetermined path relative thereto, a lifting lever movable between projected and retracted positions, said lever being pivotally mounted adjacent one end portion thereof to said guide member and having its other end portion adapted to engage a load to be lifted, and a motion controlling means operatively connecting said base member and said lifting lever for determining the path of movement of said lever other end; means for moving said lever comprising a `cam member bodily movable along said base menlber and operable to exert a force on said lifting lever to rock said lever about said guide member. a p0we1--applying screw actuatable upon rotation to move both said guide member and said lcam member relative to said base member and in a direction toward each other whereby said lever is rocked about said guide member to cause said lever other end to lift the load.

16. Means as set forth in claim 15 in which stop means is provided to limit the bodily movement of said cam member along said base member whereby continued actuation of said screw will cause said lever to rock about said guide member due to the reactive force applied thereto by said motion controlling means.

17. In a lifting jack a base support member, a guide member movable along said base member and held thereby for movement in a predetermined path relative thereto, a lifting lever pivotally mounted adjacent one end portion to said guide member and having its other end adapted to engage a load to be lifted, a motion controlling means operatively connecting said base -member and said lifting lever and acting to determine the path of movement of said lever other end upon movement of said guide member, said lever having a cam surface, a cam member bodily movable longitudinally along said base member and engageable with said lifting lever cam surface to rock said lever about said guide member, a power-applying screw actuatable upon rotation to move both said guide member and said cam member along said base member in a direction to reduce the relative distance therebetween whereby said lever is rocked about said guide member to cause said lever other end to lift the load.

18. Means as set forth in claim 17 in which stop means carried by said base member limits movement of said cam member whereby continued actuation of said screw causes said lever to rock about said guide member due to the reactive force applied thereto by said motion controlling means.

19. In a lifting jack, a base support member, a guide member held by said base member for movement in one direction relative thereto and against movement in a direction substantially perpendicular to said one direction, a lifting lever pivotally mounted adjacent one end portion to said guide member and having its other end adapted to engage a load to be lifted, a motion controlling means operatively connecting said base member and said lifting lever and acting to determine the path of movement of said lever other end upon movement of said guide member, said lever having a cam surface, a cam member bodily movable longitudinally along said base member and engageable with said lifting lever cam surface to rock said lever about said guide member, a power-applying screw threadedly connected to the guide member and journaled in said cam member and actuatable upon rotation to move both said guide member and said cam mem- 10 ber along said base member in a direction to reduce the relative distance therebetween whereby said lever is rocked about said guide member to cause said lever other end to lift the load.

20. In a lifting jack of the type in which there is a base support member, a guide member held by said base member for movement in one direction relative thereto and against movement in a direction substantially perpendicular to said one direction, a lifting lever pivotally mounted ad jacent one end portion to said guide member and having its other end adapted to engage a load to be lifted, a link pivoted at one end thereof to said base member and at the other end thereof to said lifting lever intermediate said ends of said lever and acting to determine the path of movement of said lever other end upon movement of said guide member, a cam surface operatively associated with said lever whereby bodily movement thereof will rock said lever about the guide member, a cam member bodily movable longitudinally along said base member and engageable with said cam surface for bodily movement of said surface, a power-applying screw threadedly connected to the guide member, said screw being journaled in and held against longitudinal movement relative to said cam member and a-ctuatable upon rotation to move both said guide member and said cam member along said base member in a direction to reduce the relative distance therebetween whereby said lever is rocked about said guide member to cause said lever other end to lift the load.

21. Means as set forth in claim 20 in which said base member is provided with an abutment engageable by said cam member for limiting movement thereof along said base member whereby -continued actuation of said screw will cause said lever to rock about said guide member due to the reactive force exerted by said link.

RAYMOND F. MANKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,926,610 Berglund Sept. 12, 1933 2,062,661 Baldwin Dec. 1, 1936 2,458,407 Niederhauser Jan. 4, 1949 FOREIGN PATENTS Number Country Date 272,604 Italy Mar. 14, 1930 371,968 Great Britain May 5, 1932 728,738 France Apr. 18, 1932

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