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USRE17219E - Lifting jack - Google Patents

Lifting jack Download PDF

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Publication number
USRE17219E
USRE17219E US17219DE USRE17219E US RE17219 E USRE17219 E US RE17219E US 17219D E US17219D E US 17219DE US RE17219 E USRE17219 E US RE17219E
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Prior art keywords
sleeve
screw
standard
rotation
pin
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66FHOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F3/00Devices, e.g. jacks, adapted for uninterrupted lifting of loads
    • B66F3/08Devices, e.g. jacks, adapted for uninterrupted lifting of loads screw operated
    • B66F3/10Devices, e.g. jacks, adapted for uninterrupted lifting of loads screw operated with telescopic sleeves
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66FHOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F3/00Devices, e.g. jacks, adapted for uninterrupted lifting of loads
    • B66F3/08Devices, e.g. jacks, adapted for uninterrupted lifting of loads screw operated
    • B66F3/16Devices, e.g. jacks, adapted for uninterrupted lifting of loads screw operated actuated through bevel-wheel gearings

Definitions

  • This invention relates to the class of devices known as lifting jacks, and more particularly to such a device designed to have an exceptionally long lift in proportion to its size and height when in lowered or collapsed position.
  • the jack is of that type employing a plurality of screws working one within the other and each contributinggits share to the total lift of the jack.
  • the screws are telescoped or nested within one another and within the standard of the jack when in lowered position, and driving connections are providedwhereby upon a continuous rotation ot' the driving means, which may be operated from a distance, the screws are successively and individually elevated, one at a time.
  • the embodiment of the invention here shown by way of example two nested screws are employed, the outer screw being an exteriorly threaded N sleeve which meshes within a nut formed in "the rotatable driving gear.
  • the inner screw meshes within a nut formed in the upper end of *the outer screw sleeve.
  • rl ⁇ he outer screw is lield against lrotation during its vertical travel, up or down, but is allowed to rotate in one direction only when at the upper end ot' its travel, and is allowed to rotate in the opposite direction only when at the lower end of its travel.
  • the linner screwcarkried up with it bodily Before the outer screw has-.reached the upper limit of its travel, the load supporting cap at the upper end of the inner screw will have engaged the loadY .When fthe 'outer screw reaches the upper limit of its travel, it will become locked 'Original No.
  • the rotatable driving gear is turned in the opposite direction.
  • the ratchet mechanism hereinabove referred to, will almost immediately prevent rotation of the outer screw in the direct-ion in which the driving gear is now being rotated, and the' locked with the driving gear and' is allowedl to rot-ate therewith, a ratchet mechanism at the lower end ⁇ of the standard permitting 'rotation-of the ⁇ sleeve in this direction only, which is the opposite direction to that permitted by the ratchet mechanism at the upper end of thenstandard.
  • This rotation of the outer sleeve will lower the inner screw which is still held against rotation by the load resting thereon, through the outer screw sleeve, until the load is disengaged.
  • the general object of the invention is to provide a' jack operating Yas'brieily noted above and as set forth in more detail hereinafter.
  • Another object is to provide novel means for permitting rotation of the outerV screw sleeve in one direction, when at the upper limit of ⁇ its travel, and in the opposite d1rec ⁇ tion ⁇ when at the lower limit of its travel,
  • a further'object is to provide a compact and sightly jack, which is of light weight and i economically produced, and in which the strain will be reduced to a minimum.
  • Fig. 1 is a central, vert-ical section through the jack, showing the outer screw at the upper limit of its travel, and the inner screw partially elevated.
  • Fig. 2 is an elevation of the jack on a smaller scale, looking' from the left at Fig.
  • Fig. 3 is a transverse section taken substantially on the line 3 3 of Fig. 1.. 25 tially on the line 4-4of Fig. 1,.
  • Fig 4 is a. transverse section taken
  • substan- F ig.V 5 is a view similar to Fig. 3, through a. modified form ofthe apparatus.
  • the stationary standard for the jack comprises a substantially cylindrical holloycr castl ing 1,ha.ving a broad supporting base 2. Near lts upper end the standard has an inner an.- nular supporting ring or flange 3, and above this a housing 4 partially encloses the driving mechanism hereinafter described.
  • a short stub shaft 10, journaled in an extension 11 of the housing 4, carries at its inner end a driving beveled pinion 12 which meshes with the bevi eled driving gear 9.
  • the outer end of shaft is provided with a socket 13, to cooperate with any suitable form of removable handle, whereby the jack maybe operated from a distance.
  • the'shaft 10 tilts the standard 1 through the anti-friction bear! ing 6 and in this Way the lifting or driving l
  • the outer screw 14 is in the form of a hol-r lo ⁇ w sleeve exteriorly threaded to engage withinthe driving nut 8.
  • pin 24 runs out of the upper ends of grooves 25 into an annular space 26 in 'which the pin may rotate about the axis of screw 14.
  • the pin 16 ainst the upperface of nut 8', the pin 24 has passed out of the lower ends of thev grogves 25 into a space' 27 in the lower'end of the standard, which again permits the screw 14 and pin 24 to rotate.
  • a radially extending passage or chamber 28 extends from annular Space 26 through one side of the standard.
  • a The mechanism for permitting rotation of pin v24 in one direction only is mounted in this chamber 28.
  • a cover plate 29, secured to the face of the standard by screws 30 has a pair of parallel flanges 31 extending into chamber 28.
  • v Pivot pin 32 connects the anges 31, and pawl 33 is pivotally mounted on pin 32.
  • the toe 34 of this pawl normally projects slightly over one edge of one of the grooves 25, as shown in Fig.
  • pin 24 When the screw sleeve 14 has reached the lower limit of its travel, pin 24 will have passed out of the'lower ends of grooves 25, and will commence to rotate in the opposite direction in space 27, as indicated' by the arrow in Figi 4;
  • a radially extending passage or chamber 38 In a radially extending passage or chamber 38, extending from space 27 through the-side of the standard adjacent the base plate 2, is mounted a pawl assembly quite similar to that described in 'detail above and illustrated in Fig. 3, exceptthat the pawl 39 1s oppostely positioned and permits rotation of pin 24 in the opposite direction, all as illustrated in Fig. 4.
  • a cover plate4 40 closes the opening in the lower end of thejack standard after the various parts have been assembled therein.
  • the pawl 39 rwill permit rotation of the pin 24 and sleeve 14 in this clockwise direction, asshown 1n Fig.y 4. Since the inner screw 17 is still held against rotation by the load resting thereon, it will now be moved downwardly through the rotating nut 18 and continue'the lowering of the load. This movement will continue until the load has been completely released, at which time the ack may be removed from its position beneath the load.
  • the inner screw may now be completely nested within the outer screw and the standard by manually holding this inner screw 17 against rotation while the clockwise rotation of shaft 10 is continued, or the in uer screw may be spun down to itsfnested inoperative positlon by manually rotating the supporting cap 19.
  • the several elements ot' the jack are simple, light in weight, and the'assembled jack is small and compact.
  • the shaft 10 of driving pinion 12 is slipped into its bearing 11 through one of the open sides of the housing 4 and locked in place by the washer 41 and split ring 42.
  • the driving gear and the roller bearing assembly are then laced in position vthrough the open sides of standard through the open lower end thereof and the cover plate 40 is secured in place.
  • the controlling' pawls 33 and 39 already assembled upontheir supporting plates, are slipped 5 into place in the chambers 28 and 38 and held in position 'by securing the plates 29 to the standard by means of screws 30.
  • FIG. 5 A slightly modified construction is indicated in Fig. 5.
  • a pair of diametrically o posite vertical ribs 43 are used.
  • the ends o pin 24 will engage against Athe sides of these ribs and the pin 24 and the sleeve 14 will be held against rotation in the saine manner as when grooves are used.
  • 'Ihepawl 44 extends over the upperend of one of the ribs 43, as shown in Fig. 5, so as to permit continued rotation of pin 24 in the direction of the arrow, but pre'- vent rotation thereofin the opposite direction and guide the pin down along the sides of the ribs.
  • Spring 45 normally holds pawl 44 in theposition shown, with its heel 46 against r one side of the chamber 47 in the standard.
  • the same form of pawl assembly ⁇ shown in Figs. 3 and 4 could be used with this rib construction shown in Fig. 5.
  • a lifting jack comprismg a standard, ay
  • a lifting jack comprising a standard, a Vrotatable intcriorly threaded driving Ymeinber ⁇ mounted in the standard, an exteriorly threaded sleeve meshing ⁇ within the driving memberand having an interiorly threaded 50 nut in its upperlportion, a screw meshing Within'this nut, a projection extending laterally fromithe lower end of the sleeve, vert-i- .cally extending guiding means in the standaard preventing rotation of the projection l 53 duriilg' the vertical travel of the sleeve upo1' y down, the projection passing' out vof engagey A ment with the guiding means when thesleeve reaches its extreme upper or lower positions, and oppositely disposed pawls above and below the guiding means preventing rotation of the sleeve in one direction only when at the u per limit of its travel, and in the opposite irection only when at the lower limit of its travel.
  • a lifting jack comprising a standard having a recess therein and a lifting screw mounted in the standard having a projection extending laterally therefrom, means cooperating with the projection to permit rot-ation of the screw in one direction only com-- prising a pawl-housing fitting within the recess, apawlpivoted within the housing and' projecting into the path of rotation of' the projection, and a sprlng to normally hold the pawl within the path of the projection, but permitting the pawl to swing in one direction only to yallow the projection" to pass thereby.
  • a pawl assembly adapted for use within an open-ended recess in a lifting jack standard, comprising a cover plate having flanges adapted Kto extend within the recess, a .pivot pin connecting the flanges, a pawl pivoted on the' pin, and a spring encircling the pin and bearing at one end against ione arm -of the pawl and at its other end against the ⁇ cover plate.
  • the casing having a circular groove for receiving ⁇ said projection, a spring latch arranged in the groove in position to be depressed by said projection as it rotates in one direction but constituting a positive stop for theprojection when rotating in the opposite direction, and a longitudinal guiding surface beyond the latch for guiding the projection to move longitudinally and preventing the outer screw from turning.
  • a screw'j'ack the combination with a casing having a vertical cylindrical passage with smooth walls provided with a pair of opposite longitudinal: guidestlroughout its length, of an outer screw fitting in said cylln-1 Vmais drical passage and having a pair of opposite vscent of the outer screw except as controlled by the nut, said casing havin@r a circular groove at the top of said slots
  • said casing havin@r a circular groove at the top of said slots
  • a lifting jack comprising a standard, a rotatable interiorly threaded driving member mounted in the standard, an exteriorly threaded screw sleeve meshing within the driving member, the sleeve being also interiorly threaded, a second lifting screw meshing within the interior threads of the sleeve. and cooperating means on the standard and screw' sleeve permitting vertical movement of the sleeve but-preventing continued rotation thereof duringthis vertical movement, and permitting continuousrotation of the sleeve of its travel.
  • VA lifting jack comprising a standard, a rotatable interiorly threaded driving meml ber mounted in thev standard, an exteriorly threaded screw sleeve fineshing within .the driving member, the sleeve being also interiorly threaded, a second lifting screw meshing 4within the interior threads of the sleeve,
  • a liftin jack comprising a standard, a rotatable interiorly threaded driving member mounted in the standard, jan exteriorly threaded screwfsleeve meshing within the driving member, the sleeve being interiorly when at the lower threaded, a second lifting screw meshing "means preventing continued rotation of the sleeve in the opposite direction when the sleeve is at the upper limitjof its travel and the driving member is rotated in a reverse direction to lower the ack.
  • 'A lifting ack comprising a standard, a rotatable interiorly threaded driving member mounted in the standard, an extei'iorly threaded screw sleeve meshing Within the driving member, the sleeve being interiorly threaded, a second lifting screw meshing within the interior threads ofl the sleeve, cooperating guiding means on the standard and screw sleeve permitting vertical movement of the sleeve but preventing continued rotation thereof during thisvertical movement, and permitting continuous rotati n of the sleeve in one direction when at the pper limit of its travel through the standard, and in the opposite direction when at the lower limit'of its travel, and means in each end of the standard cooperating with the guiding means on the screw sleeve for preventing continued rotation of the sleevev in one direction when at the upper limitr of its travel and in the other direction when at the lower limit of its travel.
  • a lifting jack comprising a standard, rotatable interorly threaded 'driving member mounted in the standard, an eXteriorly threaded screw sleeve meshing within the driving member, the sleevebeing also intein onedirection only when at the :up per limit 1vtion ofthe guiding means 'being yieldable to permit continued rotation'of the screw sleeve in one direction only when at one limit of its vertical travel, while preventing continued rotation at this time in the opposite direction.
  • a lifting jack comprising a standard, a rotatable interiorly threaded driving member mounted in the standard, an exteriorly threaded screw sleeve meshing withinv the driving member, the sleeve being also interiorly threaded, a second lifting screw meshing within the interior threads of the sleeve, and cooperating means on the standard and screw sleeve permitting vertical movement of the sleeve but preventing continued rotation thereof during this vertical movement, portions of the guiding means being yieldable when at the lower limit of 'its vertical travel,
  • a lifting jack In a lifting jack, a standard, a rotatable interiorly threaded driving member supported in the'standard, a hollow screw sleeve threaded within the driving member, a lifting screw threaded within the sleeve, a projection carried by the sleeve, a vertically extending guide in the standard with which the projection engages to prevent rotation of the sleeve while moving vertically, the projection passing out of engagement with the guide when the sleeve is at one limit of its vertical travel, and stop means in the standard positioned adjacent the end of the guide for ⁇ causingreengagement of the projection with the guide when the sleeve is rotated in one direction, the stop means being ineffective when .the sleeve is rotated in the opposite direction.
  • a lifting jack In a lifting jack, a standard, aftrotatable interiorly threaded driving member supported in the standard, a hollow screw sleeve threaded within -the driving member, a lifting screw threaded within the sleeve, a projection carried by the sleeve, a vertically extending guide in the standard with which the projection engages to prevent rotation of the sleeve while moving vertically, the projection passing out of engagement with the guide when the sleeve is at either limitA of its vertical travel, stop means in the standardladjacent the upper end of the guide forl causing reengagement of the projection with the.
  • stop means in the standard adjacent the lower end of the uide ⁇ for caus- .ing reengagement of the projection with the 1de when the sleeve is rotated ⁇ in the other irection,:one stop means being ineffective in one direction of rotation of the sleeve and the other stop means being ineffective in the other direction of rotation of the sleeve.
  • a lifting jack the combination of a standard, a driving vnut rotatably supported -on the standard, means for rotating the nut, an exteriorly threaded sleeve extending through and engaged by the' nut and havthread of the sleeve, guiding mechanism between the sleeve and standard for compelling the sleeve to move vertically in and out of the standard comprising devices which come into engagement with each other, when the sleeve is at one limit of its travel, for preventing the rotation of the sleeve Vin one direction only and devices which comerinto engagement with each other when the sleeve is at the other limit ofv its travel for preventing rotation of the Vsleeve in the other direction only.
  • a lifting jack comprising 'a standard, a rotatable interiorly threaded driving mem"- ber mounted in the standard, an exteriorly threaded screw sleeve meshing within the l driving member, the sleeve being also nteriorly threaded, a second lifting screw meshing within the threads in the sleeve, and cooperating means on the standard and screw sleeve for normally resisting rotary movement of the sleeve, butyieldingtoper-v mit the sleeve to turn with the driving means when at the limits of its vertical movement.
  • a lifting 'ack comprising a' standard, a rotatable interlorly threaded driving member mounted in the standard, an exteriorly threaded screw sleeve meshing within the driving member the sleeve being also interiorly threaded, a second lifting screw meshing within the ,threads in the sleeve, and cooperating means on the standard and screw sleeve for resisting rotary movement of the sleeve and thus causing the sleeve to move up at the lower limit of its travel and the driving means is rotated in one direction, the means yielding to permit rotation of the sleeve with the'driving member when rotated in the opposite direction.
  • a lifting jack comprising a standard, a rotatable interiorly threaded driving member mounted lin the standard, an exteriorly threaded screw sleeve meshing within the driving member, the sleeve being also interiorly threaded, a second ⁇ lifting' 'screw meshing within the threads in the sleeve, and cooperating means on the standard and screw sleeve for,resisting rotary movement of the sleeve and thus causing the sleeve to move down when at the upper limit of it'stravel and the driving means is rotated in one di-1 screw s eeve for resisting rotary movement of the sleeve and thus causing the-sleeve to member in the same direction that caused move vertically through the driving means travel of thesleeve tothis end of the standwhen the driving means is rotated, the means ard. being adapted to yield when ⁇ the sleeve reaches v 5 either limit of its vertical travel to permit

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Description

Reissued Feb. 19, 1929 UNITED STATES WARREN H. WALKER, JOSEPH J. MIZER, .AND IBWN E. DEARSLEYrOF RACINE, 'WIS- Raiazls PATENT OFFICE.
CONSIN, ASSIGNORS T0 WALKER MANUFACTUBJNG COMPANY, 0F RACINE, WIS- CONSIN, A. CORPORATION 0F WISCONSIN.
LIFTING mex.
reissue led December 2D, 192B. Serial No. 327,425.
This invention relates to the class of devices known as lifting jacks, and more particularly to such a device designed to have an exceptionally long lift in proportion to its size and height when in lowered or collapsed position. y
"While t-here are innumerable uses for such a jack, it is especially designed for use in the Vautomotive .industry with the new oversize or balloon tires. For this use, it is' desirable to have a -jaclr which is compact and of small vertical heightwhen lowered, in order to be `placed under the'low axle or other trame parts when the tire is collapsed, and capable of a comparatively long lift to elevate the car above its normal driving height in order that the tire may be" changed.
The jack is of that type employing a plurality of screws working one within the other and each contributinggits share to the total lift of the jack. According to this invention the screws are telescoped or nested within one another and within the standard of the jack when in lowered position, and driving connections are providedwhereby upon a continuous rotation ot' the driving means, which may be operated from a distance, the screws are successively and individually elevated, one at a time. According to the embodiment of the invention here shown by way of example, two nested screws are employed, the outer screw being an exteriorly threaded N sleeve which meshes within a nut formed in "the rotatable driving gear. The inner screw meshes within a nut formed in the upper end of *the outer screw sleeve. rl`he outer screw is lield against lrotation during its vertical travel, up or down, but is allowed to rotate in one direction only when at the upper end ot' its travel, and is allowed to rotate in the opposite direction only when at the lower end of its travel. During the upward non-rotary movement of the outer screw, the linner screwcarkried up with it bodily. Before the outer screw has-.reached the upper limit of its travel, the load supporting cap at the upper end of the inner screw will have engaged the loadY .When fthe 'outer screw reaches the upper limit of its travel, it will become locked 'Original No. 1,677,466, dated Jnl'y 17, 1928, Serial No. 740,958: led October 1,1924. Application for outer sleeve to rotate with the driving gear when at the upper limit of its travel, but prevents rotation of the screw sleeve -in the 0pposite direction, for a reason hereinafter set forth. Since the inner screw is now in engagement with the load, and prevented from rotation by its contact therewith, the rotating nut in the inner end of, the outer screw sleeve will now elevate the inner screw and continue the lifting of the load.
To lower the jack, the rotatable driving gear is turned in the opposite direction. The ratchet mechanism, hereinabove referred to, will almost immediately prevent rotation of the outer screw in the direct-ion in which the driving gear is now being rotated, and the' locked with the driving gear and' is allowedl to rot-ate therewith, a ratchet mechanism at the lower end` of the standard permitting 'rotation-of the `sleeve in this direction only, which is the opposite direction to that permitted by the ratchet mechanism at the upper end of thenstandard. l This rotation of the outer sleeve will lower the inner screw which is still held against rotation by the load resting thereon, through the outer screw sleeve, until the load is disengaged. l The general object of the invention is to provide a' jack operating Yas'brieily noted above and as set forth in more detail hereinafter. f
Another object is to provide novel means for permitting rotation of the outerV screw sleeve in one direction, when at the upper limit of` its travel, and in the opposite d1rec` tion` when at the lower limit of its travel,
while preventing rotation of this screw sleeve at all other times.
Another Objectis to provide ay jack which will positively either raise or lower, as deq outer screw has reached the upper or lower limits of its travel. i
A further'object is to provide a compact and sightly jack, which is of light weight and i economically produced, and in which the strain will be reduced to a minimum.
slble. i
Other objects and advantages of the invention will be readily appa-rent from the following detailed description of certain approved parts are easily assembled and readily acceslforms of the apparatus.
In the accompanying drawings, Fig. 1 is a central, vert-ical section through the jack, showing the outer screw at the upper limit of its travel, and the inner screw partially elevated.
Fig. 2 is an elevation of the jack on a smaller scale, looking' from the left at Fig.
.1. In this view the jaclr is completely lowered.
Fig. 3 is a transverse section taken substantially on the line 3 3 of Fig. 1.. 25 tially on the line 4-4of Fig. 1,.
Fig 4 is a. transverse section taken, substan- F ig.V 5 is a view similar to Fig. 3, through a. modified form ofthe apparatus.
The stationary standard for the jack comprises a substantially cylindrical holloycr castl ing 1,ha.ving a broad supporting base 2. Near lts upper end the standard has an inner an.- nular supporting ring or flange 3, and above this a housing 4 partially encloses the driving mechanism hereinafter described. One member 5 of the raceway for the ball bearing 6, rests upon the flange 3, while the other member 7 of the raceway su ports the rotatable nut 8 which is formed integral with the hub of driving bevel gear 9. A short stub shaft 10, journaled in an extension 11 of the housing 4, carries at its inner end a driving beveled pinion 12 which meshes with the bevi eled driving gear 9. The outer end of shaft is provided with a socket 13, to cooperate with any suitable form of removable handle, whereby the jack maybe operated from a distance. It will be noted that the'shaft 10 tilts the standard 1 through the anti-friction bear! ing 6 and in this Way the lifting or driving lThe outer screw 14 is in the form of a hol-r lo`w sleeve exteriorly threaded to engage withinthe driving nut 8. vPins l5 and 16, inserted between successive turns of the thread .of
, screw 14 at suitable points, engage the bottom.
and top faces, respectively', of nut 8 to establish the-upper and lower limits 'of travel of the outer screw. Obviously, other equivalent vinzio lof-lnner screw 17; A recess 21 in the cap loosely surroundsthe upper end of the screw stem, and the cap rests rockingly upon the rounded upper end 22 of the stein, so that the capI may tilt to some extent to, accommodate itself to the inclination of the load. A transverse pin' 23 secures the cap to the screw stem. y The projecting ends of a pin- 24, secured Athrough the lower end of screw sleeve 14, travel up and downin the vdiametrically oppositely disposed grooves 25 formed in the body portion l of the standard. Just before the screw 14 reaches v,the upper limit of its travel, with the pin against the lower face of nut 8, pin 24 runs out of the upper ends of grooves 25 into an annular space 26 in 'which the pin may rotate about the axis of screw 14. Similarly when-the screw 14 has reached the lower limit of its travel, with the pin 16 ainst the upperface of nut 8', the pin 24 has passed out of the lower ends of thev grogves 25 into a space' 27 in the lower'end of the standard, which again permits the screw 14 and pin 24 to rotate.
A radially extending passage or chamber 28 extends from annular Space 26 through one side of the standard. a The mechanism for permitting rotation of pin v24 in one direction only is mounted in this chamber 28. A cover plate 29, secured to the face of the standard by screws 30 has a pair of parallel flanges 31 extending into chamber 28.v Pivot pin 32 connects the anges 31, and pawl 33 is pivotally mounted on pin 32. The toe 34 of this pawl normally projects slightly over one edge of one of the grooves 25, as shown in Fig. 3, and the heel 35 ofJ the pawl is normally held against one side Wall of chamber 28 by the spring 36,.coiled about pin 32 and pressing at one end agaipst one face of .the pa wl llfl and at the other against the inner faceof cover plate 29, all as shown in Fig. 3. When screw sleeve 14 and pin 24 are rotating in the direction of the arrow. Fig. 3, which is the direction of rotation when the lifting screws are being elevated, one end of the pin 24 when it reaches the position shown in dot-ted lines.
will engage the cam face 37 on pa-Wl 33 and swing this pawl back against the pressure of spring 36 so that the pin 24 may continue its rotary travel past the pawl. However, when screw l14 is rotated in the opposite direction, which is the direction of yrotation when the lifting screws are being lowered, the first end of pin 24 to engage the toe 34 of the pawl 33 lili) will be prevented from further rotation by this pawl. The ends of the pin 24 will at this time be above the respective grooves and the pin 24 will be moved downwardly through the screws by the action of rotating nut 8 upon the now non-rotary screw 14.
When the screw sleeve 14 has reached the lower limit of its travel, pin 24 will have passed out of the'lower ends of grooves 25, and will commence to rotate in the opposite direction in space 27, as indicated' by the arrow in Figi 4; In a radially extending passage or chamber 38, extending from space 27 through the-side of the standard adjacent the base plate 2, is mounted a pawl assembly quite similar to that described in 'detail above and illustrated in Fig. 3, exceptthat the pawl 39 1s oppostely positioned and permits rotation of pin 24 in the opposite direction, all as illustrated in Fig. 4. A cover plate4 40 closes the opening in the lower end of thejack standard after the various parts have been assembled therein. J
Now describing the general operation bf the Jack, we will assume that the parts are in the collapsedA ,position shown in Fig. 2, which representsI the appearance ofthe jack when not in use. At this time both screws 1,4 and 17 are nested within the standard,and the pin 24 is within the annular space 27 at' the `lower end of the standard. The removable` handle is now inserted in socket 13 and rotated in a clockwise direction. This will rotate gear 9 and' nut 8 ina counter.-clockwiser direction, as seen'from above, Fig. 1, and the screw sleeve 14 and pin 24 will tend to rotate in the same direction, but will be prevented from such rotationV by the engagement of one end of pin 24 with the pawl 39. The screw sleeve 1'4 now being held from rotation by `the engagement of pin 24 with pawl 39, will be moved upwardly by the rotating nut 8 and the ends of pin 24 will pass upwardly into the grooves 25, which will continue to hold the sleeve 14 against rotation. The inner. screw 17 is still completely nested within outer screw 14 and will be moved up into engagement with the load and will liftthe same, but there will be no rotation of either screw until outer screw 14 has reached the upper limit of its travel and has become locked with nut 8 by the engagement of pin lragainst the lower face of the nut. At this time pin 24 will have passed out of grooves 25 into space 26 and will bepermittedto rotate in t 1e direction of the arrow, Fig. 3, which is the direction in which the driving nut.8 is being i rotated. The driving gear 9, nut 8 and outer sleeve 14 will now rotate as a unit, but since the inner screw 17 is now held against rota# tion by the engagement of the cap 19 with the load supported thereon, the rotation of nut 18 in the upper end of the screw sleeve 14 will now elevate the inner screw 17 which continues the lifting of the load. The rotation of the operating crank or handle is continued steadily in the same direction until thedesired elevation of the load is obtained. In order to lower 'the load, the operating crank or handle is rotated in the opposite or counterl clockwise direction, which will rotate the driving gear 9 in a clockwise direction, as viewed from above in Fig. 1. This will tend to rotate screw sleeve 14 and pin 24 in a clock wise direction asseen in Fig. 3, but the engagement of one end of pin 24 with the toe 34 oi' pa wl 33 will pre vent further rotation of the pin 24and'screw 14, and the screw 14 will be moved downwardly through the rotating nut 8, the pin 24 being guided down into the slots 25, which continue to prevent rotation of the screw sleeve. The inner screw 17, still in its extended position, will be carried bodily downward with the now non-rotary outer will commence to rotate with the nut, which rotation will be permitted by the pin 24, which has now passed out of the lower ends of grooves 25 into the space 27. The pawl 39 rwill permit rotation of the pin 24 and sleeve 14 in this clockwise direction, asshown 1n Fig.y 4. Since the inner screw 17 is still held against rotation by the load resting thereon, it will now be moved downwardly through the rotating nut 18 and continue'the lowering of the load. This movement will continue until the load has been completely released, at which time the ack may be removed from its position beneath the load. The inner screw may now be completely nested within the outer screw and the standard by manually holding this inner screw 17 against rotation while the clockwise rotation of shaft 10 is continued, or the in uer screw may be spun down to itsfnested inoperative positlon by manually rotating the supporting cap 19.
It will be seen that the complete load lift ing, or load ,lowering movement of the jack may be caused by a continuous rotation of the operating handle in the proper direction. There is no possibility of the outer screw becoming locked against lowering movement when at'the upper end of its travel, or agamst upward movement when at the lower end of its travel, by failure of the pin 24 to properly enter the slots 25, since the'engagement of the ends of the pin 24`witl1 the pawl 33 or 39 will guide the pin directly into the slots 25.
The several elements ot' the jack are simple, light in weight, and the'assembled jack is small and compact. In assembling the jack; the shaft 10 of driving pinion 12 is slipped into its bearing 11 through one of the open sides of the housing 4 and locked in place by the washer 41 and split ring 42. The driving gear and the roller bearing assembly are then laced in position vthrough the open sides of standard through the open lower end thereof and the cover plate 40 is secured in place. The controlling' pawls 33 and 39, already assembled upontheir supporting plates, are slipped 5 into place in the chambers 28 and 38 and held in position 'by securing the plates 29 to the standard by means of screws 30.
A slightly modified construction is indicated in Fig. 5. Instead of the guide slots 25, l0 a pair of diametrically o posite vertical ribs 43 are used. The ends o pin 24 will engage against Athe sides of these ribs and the pin 24 and the sleeve 14 will be held against rotation in the saine manner as when grooves are used. 'Ihepawl 44 extends over the upperend of one of the ribs 43, as shown in Fig. 5, so as to permit continued rotation of pin 24 in the direction of the arrow, but pre'- vent rotation thereofin the opposite direction and guide the pin down along the sides of the ribs. Spring 45 normally holds pawl 44 in theposition shown, with its heel 46 against r one side of the chamber 47 in the standard. Obviously, the same form of pawl assembly `shown in Figs. 3 and 4 could be used with this rib construction shown in Fig. 5.
We claim 1. A lifting jack comprismg a standard, ay
rotatable interiorly threaded driving/.member mounted in the standard, an exteriorly threaded sleeve meshing within the driving member and having an interiorly threaded nut in its upper portion, a screw meshing within this nut, a projection extending laterally from the lower end of the sleeve, vertically extending guiding means in the standard preventing rotation of the projection during the vertical travel' of the sleeve, the projection passing out of engagement with the 40 guidin means when-the sleeve reaches/oneL limit o its vertical travel, and a-pawl positioned adjacent this end of the guiding means cooperating with the projection tofprevent rotation of the sleeve in one direction only.
2. A lifting jack comprising a standard, a Vrotatable intcriorly threaded driving Ymeinber` mounted in the standard, an exteriorly threaded sleeve meshing `within the driving memberand having an interiorly threaded 50 nut in its upperlportion, a screw meshing Within'this nut, a projection extending laterally fromithe lower end of the sleeve, vert-i- .cally extending guiding means in the standaard preventing rotation of the projection l 53 duriilg' the vertical travel of the sleeve upo1' y down, the projection passing' out vof engagey A ment with the guiding means when thesleeve reaches its extreme upper or lower positions, and oppositely disposed pawls above and below the guiding means preventing rotation of the sleeve in one direction only when at the u per limit of its travel, and in the opposite irection only when at the lower limit of its travel.
3. In a lifting jack comprising a standard having a recess therein and a lifting screw mounted in the standard having a projection extending laterally therefrom, means cooperating with the projection to permit rot-ation of the screw in one direction only com-- prising a pawl-housing fitting within the recess, apawlpivoted within the housing and' projecting into the path of rotation of' the projection, and a sprlng to normally hold the pawl within the path of the projection, but permitting the pawl to swing in one direction only to yallow the projection" to pass thereby.
4. A pawl assembly adapted for use within an open-ended recess in a lifting jack standard, comprising a cover plate having flanges adapted Kto extend within the recess, a .pivot pin connecting the flanges, a pawl pivoted on the' pin, and a spring encircling the pin and bearing at one end against ione arm -of the pawl and at its other end against the` cover plate. v y
5. In a screw'jack, the combination with a casing, an outer and an inner screw, and rotary means for raising or lowering the outer screw carrying with it the inner screw, of a projection on the outer screw neart e end.
thereof, the casing having a circular groove for receiving `said projection, a spring latch arranged in the groove in position to be depressed by said projection as it rotates in one direction but constituting a positive stop for theprojection when rotating in the opposite direction, and a longitudinal guiding surface beyond the latch for guiding the projection to move longitudinally and preventing the outer screw from turning.
6. In a screw jack,"tl1e combination with a 4casing and a' hollow internally' threaded screw rotatable and movable therein, of an inner screw threaded into the outer screw and movable up and down therewith, rotary means for turning theJ outer screw to raise or .lower both screws, the outer screw having a pin at the bot-tom thereof projecting radially, a spring latch at the top of the casing having a radial edge against which the pin is adapted tofengage during its rotation in one direction to stop its rotation, a guide along the casing for the pin to guide the pin to descend without permitting the screw to turn, the casing being formed to allow the outer screw to turn in the opposite direction' when atf the elevation of said latch andjto depressthe latch and pass overit, whereby theinnerscrew will be raised when held fram turning by 'the4 .work and whereby when turned in the opposite direction the pin Wl l engage the radial edge of the latch and b e stopped and the screw will descend along said guide insteadof turn-- g. In a screw'j'ack, the combination with a casing having a vertical cylindrical passage with smooth walls provided with a pair of opposite longitudinal: guidestlroughout its length, of an outer screw fitting in said cylln-1 Vmais drical passage and having a pair of opposite vscent of the outer screw except as controlled by the nut, said casing havin@r a circular groove at the top of said slots For receiving said projections and permitting the rotation of the 'outer screw when it is raised to its upper limit, whereby when the nut is turned to raise the outer screw, it will raise it to its upper limit and then rotate it so that the inner screw will continue to rise without rotating and the upward motion of the work rest will be continuous, and means positioned in' the path of rotation'of the projections on the outer screw, which engage the projections when the nut is turned in the opposite direci tion, after the outer screw is rotated less than i tion with said guides and the further rotation a half revolution, whereby the projections on the outer screw will be stopped in registraof the nut 'in that direction will lower the outer screw without turning it and thereby lower the work rest.
8. A lifting jack comprising a standard, a rotatable interiorly threaded driving member mounted in the standard, an exteriorly threaded screw sleeve meshing within the driving member, the sleeve being also interiorly threaded, a second lifting screw meshing within the interior threads of the sleeve. and cooperating means on the standard and screw' sleeve permitting vertical movement of the sleeve but-preventing continued rotation thereof duringthis vertical movement, and permitting continuousrotation of the sleeve of its travel.
9. VA lifting jack comprising a standard, a rotatable interiorly threaded driving meml ber mounted in thev standard, an exteriorly threaded screw sleeve fineshing within .the driving member, the sleeve being also interiorly threaded, a second lifting screw meshing 4within the interior threads of the sleeve,
and cooperating means on the standard and limit of its travel.
screw sleeve permitting vertical movement of the sleeve but preventing continued rotation thereof in either direction during this vertical movement, and preventing continuous rotation of the sleeve in one direction Tonly when'at the upper limit of its travel and in the opposite direction only 10.4 A liftin jackcomprising a standard, a rotatable interiorly threaded driving member mounted in the standard, jan exteriorly threaded screwfsleeve meshing within the driving member, the sleeve being interiorly when at the lower threaded, a second lifting screw meshing "means preventing continued rotation of the sleeve in the opposite direction when the sleeve is at the upper limitjof its travel and the driving member is rotated in a reverse direction to lower the ack.
11. 'A lifting ack comprising a standard, a rotatable interiorly threaded driving member mounted in the standard, an extei'iorly threaded screw sleeve meshing Within the driving member, the sleeve being interiorly threaded, a second lifting screw meshing within the interior threads ofl the sleeve, cooperating guiding means on the standard and screw sleeve permitting vertical movement of the sleeve but preventing continued rotation thereof during thisvertical movement, and permitting continuous rotati n of the sleeve in one direction when at the pper limit of its travel through the standard, and in the opposite direction when at the lower limit'of its travel, and means in each end of the standard cooperating with the guiding means on the screw sleeve for preventing continued rotation of the sleevev in one direction when at the upper limitr of its travel and in the other direction when at the lower limit of its travel.
12. A lifting jack comprising a standard, rotatable interorly threaded 'driving member mounted in the standard, an eXteriorly threaded screw sleeve meshing within the driving member, the sleevebeing also intein onedirection only when at the :up per limit 1vtion ofthe guiding means 'being yieldable to permit continued rotation'of the screw sleeve in one direction only when at one limit of its vertical travel, while preventing continued rotation at this time in the opposite direction.
13. A lifting jack comprising a standard, a rotatable interiorly threaded driving member mounted in the standard, an exteriorly threaded screw sleeve meshing withinv the driving member, the sleeve being also interiorly threaded, a second lifting screw meshing within the interior threads of the sleeve, and cooperating means on the standard and screw sleeve permitting vertical movement of the sleeve but preventing continued rotation thereof during this vertical movement, portions of the guiding means being yieldable when at the lower limit of 'its vertical travel,
and in the other direction-only when at the upper limit of its vertical travel.
14. In a lifting jack, a standard, a rotatable interiorly threaded driving member supported in the'standard, a hollow screw sleeve threaded within the driving member, a lifting screw threaded within the sleeve, a projection carried by the sleeve, a vertically extending guide in the standard with which the projection engages to prevent rotation of the sleeve while moving vertically, the projection passing out of engagement with the guide when the sleeve is at one limit of its vertical travel, and stop means in the standard positioned adjacent the end of the guide for `causingreengagement of the projection with the guide when the sleeve is rotated in one direction, the stop means being ineffective when .the sleeve is rotated in the opposite direction.
15. In a lifting jack, a standard, aftrotatable interiorly threaded driving member supported in the standard, a hollow screw sleeve threaded within -the driving member, a lifting screw threaded within the sleeve, a projection carried by the sleeve, a vertically extending guide in the standard with which the projection engages to prevent rotation of the sleeve while moving vertically, the projection passing out of engagement with the guide when the sleeve is at either limitA of its vertical travel, stop means in the standardladjacent the upper end of the guide forl causing reengagement of the projection with the. guidev when the sleeve is rotated in one direction, and stop means in the standard adjacent the lower end of the uide` for caus- .ing reengagement of the projection with the 1de when the sleeve is rotated `in the other irection,:one stop means being ineffective in one direction of rotation of the sleeve and the other stop means being ineffective in the other direction of rotation of the sleeve.
16. In Ya lifting jack the combination of a standard, a driving nut rotatably supported on the standard, means `for rotating lthe nut, an exteriorly threaded sleeve eX- tending through and engaged by the nut and having an interior` thread, a lifting screw externall threaded to engage the interior thread o the sleeve and guiding mechanism between the sleeve and standard for compelling the .sleeve to move vertically in and out of the standard comprising devices which come into engagement with each other, when the sleeve is at one limit of its travel, for preventing the rotation of the sleeve in one rdirection only.
17. In a lifting jack the combination of a standard, a driving vnut rotatably supported -on the standard, means for rotating the nut, an exteriorly threaded sleeve extending through and engaged by the' nut and havthread of the sleeve, guiding mechanism between the sleeve and standard for compelling the sleeve to move vertically in and out of the standard comprising devices which come into engagement with each other, when the sleeve is at one limit of its travel, for preventing the rotation of the sleeve Vin one direction only and devices which comerinto engagement with each other when the sleeve is at the other limit ofv its travel for preventing rotation of the Vsleeve in the other direction only.`
18. A lifting jack comprising 'a standard, a rotatable interiorly threaded driving mem"- ber mounted in the standard, an exteriorly threaded screw sleeve meshing within the l driving member, the sleeve being also nteriorly threaded, a second lifting screw meshing within the threads in the sleeve, and cooperating means on the standard and screw sleeve for normally resisting rotary movement of the sleeve, butyieldingtoper-v mit the sleeve to turn with the driving means when at the limits of its vertical movement.
19. A lifting 'ack comprising a' standard, a rotatable interlorly threaded driving member mounted in the standard, an exteriorly threaded screw sleeve meshing within the driving member the sleeve being also interiorly threaded, a second lifting screw meshing within the ,threads in the sleeve, and cooperating means on the standard and screw sleeve for resisting rotary movement of the sleeve and thus causing the sleeve to move up at the lower limit of its travel and the driving means is rotated in one direction, the means yielding to permit rotation of the sleeve with the'driving member when rotated in the opposite direction. A n
20. A lifting jack comprising a standard, a rotatable interiorly threaded driving member mounted lin the standard, an exteriorly threaded screw sleeve meshing within the driving member, the sleeve being also interiorly threaded, a second `lifting' 'screw meshing within the threads in the sleeve, and cooperating means on the standard and screw sleeve for,resisting rotary movement of the sleeve and thus causing the sleeve to move down when at the upper limit of it'stravel and the driving means is rotated in one di-1 screw s eeve for resisting rotary movement of the sleeve and thus causing the-sleeve to member in the same direction that caused move vertically through the driving means travel of thesleeve tothis end of the standwhen the driving means is rotated, the means ard. being adapted to yield when `the sleeve reaches v 5 either limit of its vertical travel to permit y WARREN H. WALKER.
the sleeve to rotate with the driving mem- JOSEPH J. MIZER. ber upon continued rotation of the driving IRWIN E. DEARSLEY.
US17219D Lifting jack Expired USRE17219E (en)

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