US1928402A - Lifting jack - Google Patents

Description

Sept. 26, 1933. L. G. VAN slcKLE LIFTING JACK Filed May 2s, 1953 Patented Sept. 26, 1933 ir v c l N uNirisD STATE-s PATENT OFFICE Lrr'rING JACK f Louis G. Van Sickle, Racine, Wis., assignor to Walker Manufacturing Company, Racine, Wis.,

`a corporation of Wisconsin Application May 26, 193s. serial No. 672,988 A 1o claims. t (ci. 254 9s This invention relates to certain new and useadapted to lift a load to a maximum elevation ful improvements in lifting jacks, and more parin proportion to the overall height of the jack ticularly to improvement-,sinV a jack'of the screw when lowered. l Y V type comprising `a metallic t casing or standard Other objects and advantages of this invention i i andimproved friction drag mechanism mounted Vwill be more apparent from vthe following de- 60 in the standard for yieldably controlling the Vtailed description of one approved form of apparotation of the lifting screw. Y. ratus constructed and operated according to the Briefly described, the jack comprises a standprinciples of this invention' v ard, preferably composed of j mating sheet metal 'In the accompanying drawing:

i) sections which are fitted together to support and Fig. 1 is a side elevation of one of the assembled 65 almost completely house the moving parts of the jacks. jack mechanism. This standard comprises an l Fig. 2 is a central vertical section through the upper housing for supporting and partially enjack,with the lifting screws partially elevated. closing the driving nut and the bearing which Fig. 3 is apartial centralvertical section, taken Titi supportsthe nut orV equivalent rotary lifting deat right angles to the view shownin Fig. 2. 70

vice, andarvertical cylindrical guidepassage for Fig. 4 is a perspective View ofthe improved the lifting screw, said passage extending downfriction shoe. y

wardly from the housing; One of the standard These improvements are particularly adapted sections is formed to enclose a vertically extendfor use in a jack of the'double-screw type, which 20 ing recess comprising a channel portion which is shown for example in the present disclosure, 75

communicates with the guide passage, and an although it will be apparent as the description upper pocket portion which communicates with proceeds that'the same frictional control mechathe guide passage` and also with the lower portion nism could be used in a single-screw jack. The

of the housing directly beneath the bearing. A movable parts of the jack comprise an outer lift- `25 friction shoe comprising an upper head portion ing screw 1 in the form of a hollow sleeve, and 30 30 tion of theshoe urges` the friction shoe yieldably at the upper end of the inner screw 2. The outer A 40 which follow.

and a `rather' long downwardly extending Vtail an inner or upper lifting screw 2 which is threadportion fits movably within this recess, and a ed through an internal nut 3 formed in the upspring housed within the pocket and confined per end of the outer screw l. A cap or rest 4 between the standard section and the head'porwhich supports the load to be lifted is mounted 5 into engagement with the threaded surface of screw 1 is threaded through and supported by a the screw so as to tend toprevent rotation of nut 5, which in turn is supported on an antithe screw and cause the screw'to move verti' friction bearing assembly comprising upper and cally when the driving nut through which the, lower raceways 6 and '7 between which is a circu- -'J screw is threaded is rotated. f lar series of ballbearings 8 carried by a cage 9. 90 The principal object of this invention is to pro- A short, laterally projecting operating shaft 10 vide a simple, efficient and inexpensive jack .of is provided with a soclreted head 11 at its outer the type briefly referredi to` hereinabove and end whereby connection is made with a removable disclosed more inv detail in the specifications operating handle, and a bevel pinion 12 formed at Y Y the inner end of the shaft 10 meshes with a bev- Another Objectis t0 provide improved means eledgear i3 formed on the nut 5. It wiiinow be for rildlablyy Controlling Phe mail@ 9i the llftgeen that if the Operating shaftio is rotated, the ing. Sere-W in @Jack of this type' nut 5- will be rotated about the vertical axes of Another object is to f provide an improved the liftin screws and if the outer screw 1 is held 15 screw-controllinglmeans which will permit a g Y J 00 from rotation, this screw willl be elevated or low- ;lmum elevatlqn of the 'Contrgued mme ered depending upon the direction of rotation of v ting shaft 10 and nut 5. Another object is. to provide an maproved fric- Opcra tional dragshoe which is non-tiltable and which The Improved pressed metal housmg fori Sup .5o Wm Simultaneously engage a plurality of threads portingand enclosing the movable elements of 105 on the screw so as to provide a smooth, and, nonthe jack COmDliSeS; in the embodiment here locking engagement with the screw at all times. Sh0WI1, a has? plate 14 and a Dall O-Slmllal lll)- Another object is to provide-an improved type right standard sections 15 and 16. The base plate of friction shoe for use ina jack of thisgtype.V 14 is preferably formed ofv a single piece of 55 I Another object-is tov provide a lifting jack stamped or pressed sheet metalwhich is strength4` 11,0

2 ened by means of the side flanges 17 and corrugations 18.

Each section 15 and 16 of the upright standardV is formed to enclose substantially half 'of an upper disk-like housing or chamber 19, a laterally projecting bearing chamber 20 in which the operating shaft 10 is journaled, and a vertically extending cylindrical passage 21 which serves as a housing and guide for the outer lifting screw 1. The upper housing 19 encloses the nut 5 and the supporting bearing assembly, the lower raceway 'I of the bearing resting on the annular shoulder 22 formed by the bottom wall of housing 19 adjacent the upper end of the guide passage 21. Each standard section 15 and 16 is provided with a laterally extending side flange 23 which extends substantially radially from the central vertical axis of the jack, and which projects'from all of the side and upper portions of the standard member except at the outerend of the bearing 20 for operating shaft 10. At the top of the housing sections, this flange 23 extends upwardly as part of a vertical cylindrical collar 24 in vwhich the upper portion ofnut 5 is rotatably fitted. Each standard section is preferably provided with a' vertically extending hollow rib 25 which is centered in a plane substantially perpendicular to the plane of the side flanges 23. This rib'may extend substantially from the upper chamber 19 to the lower end of the standard section and serves to brace and stiffen the jack housing. c

In order to assemble this jack vthe several movable-elements of the jack are rst assembled as shown for example in Fig. 2 and placed within one ofthe standard sections, and the two standard sections 15 and 16 are then assembled together about the movable elements by securing the side flanges 23 in face contact with one another in any suitable manner. The side flanges may be spot welded or riveted together, and one of' the flanges may be made of greater width and folded over the other flange so as to bind the two standard sections firmly together.Y The lower end porc tions ofthe upright standard sections are secured to the base plate 14 in any suitable manner. In the example here shown, horizontally extending flanges 26 formed at the lower ends of the two standard sections are riveted to the base plate as indicated at 27.

The present invention relates more particularly to improved means, especially adapted to be mounted in a pressed metal casing or standard of this type, for controllingthe rotation of the lifting screws. It-will be apparent that if the screw 1 is free to rotate, it will simply rotate with the driving nut 5 and will be neither raised or lowered when the shaft 10 and nut 5 are rotated. If the rest or cap 4 (whichis non-'rotatably secured to the upper end of inner screw 2) Yis in engagement with a load, this inner screw will be held from rotation. If the driving nut 5 is rotated, the outer screw 1 will either rotate with the nut 5, or will be held from rotation by the .frictional rotation of inner screw 2 with the nut 3 formed in the upper end of the outer screw. In the first case the inner screw will be elevated through the nut 3. In the second case both of the non-rotating screws will be elevated through the driving nut 5. In either event the load will be lifted. In the'event that the outer screw is elevated before the inner screw is extended (as will be the normal operation), the upward movement of the outerscrew will'be limited by the engagement ofthe stop 28, formed in any suitable manner in this outer screw', with the threads Of v sleeve 1`will rotate with the nut 5 continued elevation of the upper the driving nut 5. Thereafter .the outer screw and cause .the screw 2 through the now rotating nut 3 in the upper end of screw l. When suitable stops formedor secured in the lower end of screw 2 engage the bottom of nut 3, the maximum elevation of the jack has been reached. l

It is customary to provide means in a jack of this type for controlling the rotation of the outer screw 1 so that this screw Will be raised or lowered when the driving nut 5 is rotated even though there is no load on the jack, thus providing means for raising the cap 4 into engagement with the load. For this purpose different forms of friction drag mechanisms have been provided which constantly engage the threaded outer surface of screw 1 so as to continuously tend to prevent the rotation of this screw. As a result the screw 1L will be continuously raised or lowered whenever the nut 5 is rotated until such vertical movement is prevented by the screw 1 reaching either of its limits of travel, after which the screw 1 will rotate with the nut 5 against the resistance of the friction drag mechanism. The present invention relates particularly to an improved 1 form of device for imposing this frictional resistthis recessisenlarged at 31 to form a pocket which opens directly through shoulder 22 into the lower portion of chamber 19. The inner portions of pocket 31 and recess 30 communicates directly With the vertical guide passage 21 for the lifting-screw.

The improved friction .shoe A32 is preferably formed of a single piece of sheet metal stamped into substantially the shape shown in Fig. 4. This shoe comprises a downwardly extending tail portion 33 of channeled cross section, comprising side flanges 34 which flt slidably against the side walls of the recess or channel 30. The head p0rtion of the shoe, which flts within the pocket 31, comprises the widened side flanges 35 which are connected by the top wall 36 which serves as an upper wall for pocket 31 directly beneath the lower surface of raceway 7 of the bearing assembly. A short coiled expansion spring 37 is housed within the head'portion of shoe 32 and pocket 31, and is confined under compression between the outer wall of the pocket and the inner face of the friction shoe so as to urge the shoe yieldably into engagement with the threaded outer surface of the lifting screw 1. It will be understood that kthe shoe and spring will be housed substantially within the recess 30 and pocket 31 so that the inner surface of the shoe will form substantially a portion of the surrounding cylindrical wall of passage 21, but this inner surface of theY shoe will always bear frictionally against the surface of the screw.

Friction devices of this general type have heretofore been used in which a spring, or a springpressed ball or plug is forced against the threaded surface of the screw. 'A ball will bump over the surfaces of the thread causing an uneven movement, and the same will be true of a springpressed plug unless the inner surface of this plug is ofsufllcient vertical extent to span more than one of the threads. Furthermore, such hoodies a device has a tendency7 to tiltand bind in the enclosing housingor lockA against the threads. This is especially true where the frictional device is mounted' in a stamped metal housing wherein the'roundedcorners of the edge portions of the pocketor recess, (for example as shown at 38) are apt to cause the spring to exert a. tilting force on the friction shoe or plug. t The impmvedffriction shoe 32 herein disclosed, provided with the long channeled tail portion 33, is adaptedtoY bear simultaneously on several of the threads of g the screw sorthat the frictional nesistance will be smooth and even at all times. The engagement of this channeled `tail portion within the longitudinal recess 30 and the engagement of the head flange 36 vwith the lower surface of the bearingwill effectually prevent tilting of the shoe in any direction, even when the screw is raised to a maximum elevation. It will be noted that this device is positioned directly beneath the supporting bearing and nutso that the screw may be elevated to a maximum extent without passing out of engagement with the frictional drag mechanism, This is essential in a jack of this type wherein it is desired to provide a jack of mini-y mum overall height when lowered so that it may be positioned under very low loads, and at thev same time provide a maximum `elevation'when the lifting screwsareraised. It will also be noted that the upper portion of the nut 5 is cupped out Vatv 3l)V toreceive the cap 4 when the screws are 'lowered so that the jack may be collapsed to a minimum height asindicated in Fig. l.

Assuming that the jack when placed beneath thev load but not yet in engagement therewith is completely telescoped-or lowered as shown in Fig. l, when the -driving shaft l0 and-nut 5 are rotated in the proper direction the 'friction shoe device will prevent rotation of the outer screw 1 and cause the nested `screws 1 and 2 to be raised out of the standard until the load-is vaccepted by the lifting head 4.l The lifting operation will then be continued until the outer screw 1 has been raised to its upper limit, determined by the engagement of stops 28 with the lower surface of nut A5. Thereafter the outer screw 1` will'rotate with the nut 5 'and willraise" the inner screw 2a`nd the load carried thereby, since the 1 inner screw 2 is held from rotation by the load and will be elevated by the rotating nut 3. In order to lower the load, the shaft 10 will be rotated in the'opposite direction. l When the rest 4 has moved out of engagement with the load, the outer screw 1 may be completely lowered by continued rotation of shaft 10`inthis direction, and the inner screw 2 may then be completely lowered by spinning it down through the nut 3. In case the load to be lifted is positioned at' an unusual height, with relation -to the lowered height of the jack, the innerscrew 2 may first voe spun up a snort distance by hanusotnat .the

cap 4 will engage' the load before the outer screwl:V has been completely elevated.

It will be apparent that this `lfrictionshoe device will also be useful-in a -singlescrew jack, that is a jack of the type in which the load is carried directly bythe upper endof screw l and there is no inner screw. In such a jack, this friction shoe device will cause the screw to move upwardly until it engages the load. It will also permit the screw` tov becompletely lowered'oy rotation o: the `opwarming shaft, after the load has been released.V Y

It'willfbeopparentthat this frictional drag mechanism is quite simple and economical to v of, the recessV manufacture and assemble in the jack.. The recess for housing the device is stamped` in the standard section as a part of the original stamp-` ing operation. The -friction shoe is' a single stamping, and the spring and shoe are merely positioned within the recess in the standard section and are` held in position by the movable elements ofthe jack when the jack is assembled. No other securing means are necessary for either the spring or the shoe. 1

I claim:

1.- In combination with theV moving parts of a' lifting jack comprising a vertically movable lifting screw, a nut through which the screw is threaded, and means for rotating the nut,a

standard for supporting the moving parts, said standard being formed with a vertically extending guide passage for the screw and a vertically extending recess communicating vwithv the passage at one side thereof, a friction shoe extending longitudinally of the screw so as to simultaneously engage a plurality of threads thereon and housed within the recess, the shoe' being of chan neled cross-section and having its outwardly extending side ilanges slidably engaging the side walls of the recess, and a spring housed within the recess and the channel of the shoe and con'- llned between the shoe and standard to urge the shoe into engagement with the threaded surface of the screw. i i

2. In combination with the moving parts of a lifting jack comprising va vertically `movable lifting screw, a nut through which the screw is threaded, and means for rotating thenut, a standard for supporting the moving parts, said standard being formed with a vertically extending guide passage for the screw and a recess communicating withthe passage at one side there comprising a vertically extending channel and a pocket opening into the channel, a friction shoe of channeled cross-section housed within the'channel portion of the recess with its 1 outwardly extendingside flanges slidably engaging the side Walls ofthe recess, said shoe having a length sufficient tol simultaneously engage a plurality of threads on the screw, and a coiled spring housed within the pocket and the channel of the shoe and confined'between the shoe and standard to urge the shoe into frictional engagement with the threaded. surface of the screw.

3. In combination with 'the moving parts of a lifting jack comprising 'a vertically movable lifting screw, a nut through which the screw is threaded, and, means for rotating the nut, a bearing for supporting the nut, a standard for partially enclosing the moving parts and supporting the bearing, said standardV being formed with an upper housing for supporting the bearing and nut, a guide passage for the screw extending vertically downward from the housing, a verti-` cally extending recess of channel form communicating with the passage and having a pocket at its upper end directly below Vthe bearingsupporting portion of the housing, a friction shoe extending longitudinally of the screw so as to simultaneously engage a plurality of threads thereon and comprising an uppei` hollow head portion extending into and guided within the pocket` and downwardly extended tailportion housed within and guided by the recess, and a. coiled spring housed -withinthe pocket and the head of the shoe and-confined between the stand# ard and shoe to urge with the threaded surface of the screw.'

4. In combination with the moving parts of iio a lifting jack c omprising a vertically movable lifting screw, a nut through which the screw is threaded, and means for rotating the nut, a bearing for supporting the nut, a standard for partially enclosing the moving parts and supporting the bearing, said standard being formed with an upper housing for supporting the bearing and nut, a guide passage for the screw extending vertically downwardfrom the housing, and a vertically extending recess of channel form opening into the passage and housing, a friction shoe of channeled .cross-section housed within the recess with its outwardly extending side anges slidably engaging the .side walls of the recess, and a spring housed within the recess and the channel of lthe shoe and conned'between the shoe and standard to urge the shoe into engagement with the threaded surface of the screw.

5. In combination with the-moving parts of a.l lifting jackfcomprising a `vertically movable lifting screw, a nut through whichthe screwis threaded, and means vfor rotating the nut, a

. confined between bearing for supporting the nut, a standardfor partially enclosing the moving parts and supporting the bearing, said standard being formed with 'an upper housing for supporting the bearing and nut, a guide passage for the screw extending vertically downward from the housing, and a vertically extending recess of channel form communicating with the passage and having a pocket at its upper end, directly below the bearing-supporting portion of the housing, a friction shoe extending longitudinally of the screw so as to simultaneously engage a plurality of threads thereon and housed withinvthe recess, said shoe comprisingan upper horizontal fiange extending beneath the bearing and forming' an upper movable Wallfor the pocketand a downwardly extending tail portion of channeled cross-section engaging slidably. within the y.channel ofv the recess, and a coiled spring housed withinl the pocket vand the upper portion of the shoe and the shoe and standard-to urge the shoe into vfrictional iengagexnent'with the threaded surface 'of the screw.

. 6. In, combination with a section of pressed 4metal lifting Ajack housing, said section being formed with a portion ofv a cylindrical Yguide passage fora lifting screw and alsoformed with a channel extending longitudinally of the passage and opening thereinto, a friction shoe of channeled cross-section positioned in the recess with its outwardly'extending sideflanges fitting slidably against the side walls of the channel, and a. spring confined within theA channel'and shoe and adapted to urge the shoe into frictional engagement with the threaded surface of a lifting screw when positioned `within the passage.

' 7.. In combination with a section of a pressed metal lifting, -jack housing, said section being ,formedwith a portionof acylindrical guide passage for a lifting screw and'v also formed with a channel extending longitudinally of the passage and opening thereinto, a friction shoe of channeledr cross-Section positioned in the recess with its outwardly extending side flanges fitting slidably against the side walls ofthe channel, there being a pocket formed inthe wall of the section and opening into the outer wall of the channel, and a coiled spring housed within the pocket and a portionof the shoe and adapted to urge the shoe into frictional engagement' with the threaded surface of a lifting screw when positioned within the passage.

i .8. Incornbination with a section of a pressed metal lifting jack housingsaid section being formed with aportion of a cylindrical guide paslage for a. lifting screw and also formed with a portion of an enlarged chamber for housing a rotary element of the jack, the passage opening into this chamber, the section also being formed with a recess comprising a channeled portion extending longitudinally of the passage and communicating` therewith and opening at one end into the chambenthis end of the recess being enlarged to form agpocket, a friction shoe of channeled cross-section ypositioned inthe recess and comprising a longitudinally extending tail portion fitting within the Vchanneled portion of the recess for movement toward or from the passage and a head portion fitting within` the pocket with an end wallY which vcloses the side of the pocket opening into the chamber, and a coiled spring confined within the pocket and the head portion of the shoe and tending to urge the shoe into the passage to bear'frictionally against the threaded surface of a lifting screw when positioned within the passage. 9, In combination with the moving parts of a lifting jack comprising a vertically movable lifting screw, a nut `through which the screw is threaded, and Ameans for rotating the nut-,a standard for supporting the moving parts, said standard being formed with a vertically extending guide passage for the screw, a vertically extending recess communicating .with the passage at one side thereof and apocket extending outwardly from anuupper portion of they recess, a friction shoe extending longitudinally of the screwso as to simultaneously engage a plurality of `threads thereon and housed within the recess, .said-shoe vhaving an upper hollowk head portion adapted to extend within the pocket and a downwardly extendingtail portion guided within the recess, and a spring confined within the pocket and head of the shoe to urge the shoe into engagement with the threaded surface of the screw.- Y Y f l0. In, combination with the moving parts of Va lifting jack comprising a vertically movable lifting screw, a` nut through which the screw is threaded, and means forrrotating the nut, a bearing for supporting the nut, aV standard for partially enclosing the moving parts andl supporting the bearingksaidpstandard being formed with anI upper housing for. supportingthe bearing and nut, a guide passage for the screw extending vertically downward fromthe housing and a vertically extending recess of channel form communicating with the passage and having an outwardly extending pocket at its upperend directly below the bearing supporting portion of the housing, a vfriction shoe extending longitudinally of the screw so as to simultaneously engage a'plurality of threads thereon, said shoe being formed with an `upper head portion extending into and guided by the-pocket and comprising an upperv horizontal flange extending beneath the bearing and forming an 'upper moyablel wall for the pocket, thel shoe also, being formed with a downwardly extending tail portion engaging'slidably 4within the channel of the recess, and a coiled lspring housed within the pocket and the head. of the screw and confined between the shoe'. and standard/to urgethe shoe into frictional engagement with the threaded surface of the screw.

" LOUIS G. VAN vSICKLE.

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