US1688862A - Lifting jack - Google Patents

Description

Oct. 23, 1928.

C. D. ELLWOOD LIFTING JACK.

Filed April 26, 1926 5 sheets-sheet 1 TufeTL 0T* m, MN QN N E N C. D. ELLWOOD LIFTING JACK Filed April 26, 1926 5 Sheets-Sheet wm @www C. D. ELLWOOD ci 23, W28.

LIFTING JACK Filed April 26, 1926 3 Sheets-Sheet mm@ UMH/w Elli Patented Oct. 23, 1928.

UNITED STATES PATENT `o1=l=1cl:r..-

CHARLES D. EIJLWOOI), OF RACINE, WISCONSIN, ASSIGNOR TO WALKER MANUFAC- TUBING COMPANY, 0F RACINE, WISCONSIN, A CORPORATION OF WISCONSIN.

LIFTIN G 'JACKv Application led April 26, 1926c ASerial No. 104,760.

This invention relates to lifting jacks, and

more particularly to a4 heavy duty 4jack designed for use about garages and repair shops lmechanism carried by the carriage is of very small height, or is capable of being depressed to an extremely low position, so that the assembly can be pushed under very low hanging loads, and operated in this position. The

lifting mechanism mounted at the forward' end y:of the carriage comprises a bell crank lever having a rather long forwardly extending lifting arm, and a comparatively short downwardly extending power arm. 'lhe driving and reversing mechanism is located at the rear of t-he jack, and a horizontally movable rackbar or push-rod acts against vthe downwardly extending power arm of the bell crank. The driving mechanism is actuated b a long, jointed actuating handle or lever. he main portion of this lever always extends substantially .horizontally from the carriage, and when operated, swings vertically through. a compartively short arc.. rllhis portion of the handle is, like the carriage, adapted to be operated beneath the low hanging portions of a truck or bus. An extension member is pivoted to the rear endof this main handle portion, the extension being operable in either a horizontal or vertical position, or if desired, in an intermediate position, according to the space `available for such operatiorm L @ne object of the invention is to provide a jack of the type described, which is extremely low, so as to operate beneath very low hanging loads, and at the same time one which may be easily shifted into position and which may be conveniently operated from a distance.

Another object is to provide a new and im- Another object is to provide an improved form of operating lever or handle, which is capable of adjustment to the most convenient position for operating under very low hanging loads.

Other objects and advantages of this invention will be apparent from the following detailed description of certain approved forms of the apparatus.V Y

ln the accompanying drawings:

lig. les a side elevation of the complete Jac Fig. 2 is a plan View, partially broken away, of the carriage, this View being on a considerably larger scale than Fig. l.

Fig. y3 is a longitudinal vertical section through the portions of the jack shown in Fig. 2.

Fig. 4 is a transverse vertical section taken substantially on the line 4 4 of Fig. 3.

Fig. 5 is a detail of the operating handle, on an enlarged scale.

Fig. tl is a detail view showing the adjustlng handle for the operating lever. 'l

Fig. 7 is a view, similar to Fig. 3, showing a modification of the lifting mechanism.

The main supporting frame l carries at its front end an axle 2, on the ends of which are mounted the supporting rollers 3. Near the rear end of the frame, a pair of rollers 4 are swiveled on vert-ical axes 5 in the outwardly projecting bracket arms 6, rlhe swiveled rollers 4 permit the carriage to be steered into position under any desired portion of the load, and enable the carriage to be turned on a short radius. The front rollers `3 have a rather wide wheel base, and the brackets 6 space the rollers 4 even farther apart so that a wideirm foundation is provided for the jack,

The lifting provide two side arms l0, which are pivoted at 1l, to the sides of one upper corner of the lifting Sleeve l2. A link or reach rod 13 is forked at its lower forward end and pivoted at i4 about a lug l5 extending from the lower dei roe

corner of lifting sleeve 12, and its upper rear end is pivoted on a shaft 16 extending between the side members of frame 1. The spacing of shafts 9 and 16 is substantially the same as the spacing of shafts 11 and 14,

vand the reach rod 13 is of substantially the same effective length as the load arm 7 of the bell crank, so'that the plane of the axesl of shafts 11 and 14 will always remain substantially arallel to the plane of the axes of shaftsg and 16. A lifting head or shoe 17 having a plurality of upwardly extending lugs 18 to support the load is carried by a vertical stud or shaft 19'threaded to engage in a nut 20 mounted within the lifting sleeve 12. The downwardly extending powerv arm 8 of the bell crank consists of a pair of similar side members spaced apart to permit the link or reach rod 13 to pass therebetween. Upon a shaft 21 mounted in the lower ends ofthe power arms 8 is mounted a broad faced antifriction roller 22.

As power is applied to the lower end of the downwardly extending power arm 8, in the form of a p'ush from right to left, as seen in Fig. 3, the load arm 7 will be elevated, different elevated positions being indicated in dotted lines in Fig. 3. It will be noted that the parallel arm movements of link 13 and arm 7 will cause the sleeve 12 to move so that the axis of screw shaft 19 will remain vertical at all times, and hence the lifting head or sleeve 17 will always remain horizontal in proper load-supporting position. When the shaft 19 is screwed down within sleeve 12 as far as possibleand the load arm 7 is comletely lowered, as indicated in solid lines in ig. 3, the lifting head or shoe 17 will be positioned only slightly above the upper faces of sup orting rollers 3 and may be positioned' beneat a very low hanging load. If a higher -load is to be engaged, and a greater vertical lift is desired, the shoe 17 may be rotated by hand to elevate the screw 19, thus increasing the initial elevation of the shoe and conse# quently increasing the height to which it will be elevated when the lifting bell crank is operated.

In the form of bell crank shown in Fig. 3, the remote ends of the forked extensions of load arm 7 and power arm 8 are bridged by side connecting members 23, which span the sides of reach rod or link' 13 and serve to strengthen the bell crank.

Any approved means may be used for aplying power to swing the wer arm 8 of the hell crank, one improved orm of such mechanism being indicated in Figs. 2 and 3. push-rod or rack bar 24, provided with teeth 24 on its upper surface, is guided for hori` zontal sliding movement in the frame 1. A cross-head`25 is mounted on the front end of this rack bar 24, and a horizontal shaft 26 passing through the rack bar and cross-head carries guide rollers 27 on its ends` the .rollers being confined between horizontal trackways 28 in the frame 1. The cross-head has 'a broad, flat face 29, positioned in a vertical plane, against which the roller 22 on power arm 8, is adapted to engage. It will be noted that .the lower end o f power arm 8 swings through a rather long flat arc in a vertical plane, whereas the rack bar 24 has a Arectilinear movement in this sameplane. During this movement the roller 22 will move up and down along the fiat forward face 29 of the cross-head.l

A driving pinion 30 mounted on a horizontal shaft 31 is always in mesh with the rack bar 24.- A ratchet wheel 32 is also secured to shaft 31 at'one side of the pinion 30. The main actuatin handle or lever 33 has a housing 34 secure to its forward end, the housing being pivoted at 35 on a horizontal shaft in the upper rear portion of supporting frame 1. An actuating pawl 36 is pivoted on shaft 37 within housing 34, and normally held by spring 38 in-engageinent with the teeth of ratchet wheel 32. A locking pawl 39 is pivoted on horizontal shaft 40 in the frame 1, and is normally held by spring 41 in engagement with the teeth of ratchet wheel 32. i 1

The adjustable extension 42 of the operating handle is pivoted at 43 to the rear end 'of the main operating lever 33. An arcuate plate 44 mounted on the rear end of lever 33 extends between the forked lower end portions of extension 42, and is provided with a series'of notches 45 to be selectively engaged 10 handle or loop 48 by means of which the dog 105 may be retracted against the action of spring 49 and moved to another selected notch 45 in the arcuate plate 44. In this way, the exten'- sion 42 can be used as a substantially horizontal extension of the main lever 33, as 'shown in 110 Fig. 1, or may be moved to a vertical position, as indicated in dotted lines in said figure. By providing sufficient intermediate notches 45, the extension 42 may be moved to any desired position intermediate the two positions.

indicated.

When the jack is being operated, the main handle portion 33 is oscillated up `and down through a comparatively shortarc so that it always extends substantially in a horizontal direction and may be operated beneath very low hanging parts of a carriage frame, such A as the rear end of a bus. The handle portion 33 is of such length that the rear end thereof will ordinarily project out from beneath the load, and the extension member 42 may be inclined at a convenient angle for operation. -If there is not sufficient room to have this extension 42`project horizontally or at an angle, it may be arranged vertically, as shown 13 in dotted lines, Fig. 1, and the jack operated by imparting an up and down motion to this extension 42. If over-head members prevent the upward inclination of handle 42, it`

may be used as substantially a horizontal extension of the main handle 33, as indicated in solid lines, Fig. 1.

:When the jack is to be used to elevate a load, the carriage 1 is shoved into position beneath the load, by means of the handle 42, the swiveled rear wheels or rollers 4 permitting the carriage to be steered into the desired position. When lifting head 17 is beneath Athe load, the`lever 33 is oscillated up'and tooth is being held in position by the locking pawl 39 which is in engagement with another tooth of the ratchet. On the downstroke of lever 33, the pawl 36 will rotate the ratchet 32 in a clockwise direction, as seen in Fig. 3, the length of one ratchet tooth, until the locking pawl 39 has snapped into engagement with the next succeeding tooth. Repeated oscillations of the lever 33 will gradually rotate the ratchet 32, and consequently-the pinion 30, in a clockwise direction, and slowly impart-a rectilinear sliding movement toward the left, as seen in Fig. 3, to the rack bar 24. Since cross-head 25 is pressing against the roller 22 at the lower end of power arm 8 of the bell crank, the bell crank will be swung about its pivot 9 to gradually elevate the load arm 7 to the dotted positions indicated in F ig. 3. As previously noted, the reach rod 13 operates to maintain the lifting head 17 in a horizontal position beneath 'the load at all elevations of the load arm 7.

vWhen tlfe load is to be lowered, it is necessary to gradually retract the rack bar 24,

toward the right in Fig. 3, and this is done by permitting a gradual counter-clockwise rotation of the ratchet 32. Numerous forms of reversing mechanisms are well known in this art for controlling thelifting and locking pawls to permit the reverse movement of the ratchet as the-operating lever is oscillatecl. The mechanism here artially indicated is of the type disclosed andD claimed in the copending application of Dearsley Serial No. 73,187, led December 4, 1925. Briefly described, a reversing member 50, pivoted about the axis of shaft 31, is normally actuated in one direction by a spning 51 confined between a lug 52 on supporting frame 1 and a bracket extension 53 on the reversing member 50. When permitted to move under the influence of spring 51, the reversin member will, through cam projections whic successively engage the two pawls, alternately push these pawls,y

out of engagement with thev ratchet wheel 32. The operation is such that the lifting pawl 36 will be engaged with the ratchet and the locking pawl 39 will be held out of engagement during the upstroke of the lever 33, so as to permit a partial counter clockwise rotation of the ratchet. During-the down-stroke Iof the lever 33, the locking pawl will hold the ratchet, but the operatln pawl 36 will be disengaged. 'lhus the v oad is gradually lowered.' During the lifting operation, reversing member 50 is held out of operation, with spring 51 compressed, by means of a link connection extending to the operating lever 54 carried by the lever 33. Since the specific form of this reversing mechanism forms no part of the present invention, further description thereof should be unnecessary. Other forms of reversing and liftin l mechanism could be substituted, although t e form here indicated is preferred.

A somewhat modified form of the lifting mechanism at the front end of the jack is shown in Fig. 7. As here shown, the lifting .bell crank comprises a forwardly extending load arm 55, and a downwardly extending power arm 56, the bell crank being pivoted intermediately on horizontal shaft '57 in the supporting frame 1. The forwardly extending load arm 55 is formed of two similar side members, or is forked, and the free ends pivoted on shaft 58 at the upper end of lifting sleeve 59. A pair of similar links or reach rods 60 have their forward ends pivoted at 61 to the lower end of the lifting sleeve .59," and their rear ends are pivoted at 62 to the respective sides of supporting frame 1. The downwardly extending power arm Y 56 is pivoted at its lower end at 63 to the forward end of an operating rod 64, which may be connected at its other end to a rack bar similar to the rack bar 24 hereinabove described, or may be connected with any other suitable form of operating mechanism. Lifting head or shoe 17 has its vertically extending screw shaft 19 threaded into a nut 420 carried by sleeve 59, whereby the lifting shoe Can be verticall adjusted within the sleeve, all as' describe hereinabove, in connection with the first described form of jack.' The spacing of the axes of pivots 57 and 58 is the same as that between pivots 61 and 62, also pivots 57 and 62 are spaced the same as pivots 58 and 61, so that the reach rods 60 will serve to give a parallel motion to the sleeve 59 and always maintain the lifting head or shoe 17 in a horizontal position. Different portions of the several parts, when the jack is elevated,

pivoted at the free end of the forwardly extending arm, means for maintaining the lifting head horizontal at all elevations, a pushrod guided for horizontal movement in the frame, power means for reciprocating the rod, a cross-head at the forward end of the rod, and means at the free end of the power arm of the bell-crank which swings in a vertical arc across the path of the push-rod and is engaged by the cross-head.

2. In a lifting jack, a supporting frame, a bell crank lever pivoted in the frame to oscillate in a vertical plane and comprising a forwardly extending lifting arm and a downwardly extending power arm, a lifting head pivoted at the free end of the forwardly extending arm, aI push-rod guided for horizontal movement in the frame, means for reciprocating the rod, a cross-hea l at the forward end of the rod, and means at the free end of the power arm of the bell-crank which swings in a vertical arc across the path pf the pushrod and is engaged by the cross-head.

3. In a lifting jack, a supporting frame, a bell crank lever pivoted in the frame and comprising a. forwardly extending lifting arm and a downwardly extending power arm,

a lifting head pivoted at the free end of the forwardly extending arm, a push-rod guided for horizontal movement in the frame, a cross-head carried by the forward end of the push-rod, a roller pivoted at each side of the cross-head, track-ways in the frame for the rollers, a roller pivoted in the lower free end of the power arm of the bell crank and adapted to engage against the front face of the cross-head, and means for reciprocating the push-rod in the frame.

4. In a lifting jack, a supporting frame, a bell crank lever pivoted in the frame and comprising a forwardly extending lifting arm and a downwardl extending power arm, a lifting head pivote at the free end of the forwardly extending arm, a rack-bar guided for horizontal movement in the frame, a cross-head mounted at the forward end of the rack bar, rollers pivoted at the sides of the crosshead, track-ways in the frame for the rollers, a roller pivoted at the free lower end of the power arm of the bell crank and ada ted to engage against the front face of t e cross-head, a pinion mounted in the frame and engaging the rack, and means for rotating the pinion in either direction.

5. In a lifting jack, a supporting frame, lifting kmeans pivoted in the frame to oscillatein a vertical plane and comprising a lever arm, aroller pivoted in the free end of the arm and adapted to swing in a vertical arc, a member guided for rectilinear movement in the frame in the plane of movement of the lever and having a substantiall flat face extending at right angles to its ine of move ment against which the roller engages, means for guiding the member, and means for reciprocating t-he member in the frame.

6. A lifting jack comprising a carriage, rollers for supporting the carriage, lifting means mounted in the forward ortion of the carriage, means for raising an lowerin the lifting means comprising an operating lever pivoted to the rear of the carnage, the lever comprisingr a main portion which extends substantially horizontally and is adapted to swing through a short vertical are, and an extension pivotally attached to the free end of the main lever and adjustable to extend upwardly therefrom at any selected one of a plurality of angles, and means for rigidly holding the lever sections together in any selected position of adjustment.

CHARLES D. ELLWOOD. l

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