US2135938A - Lifting jack - Google Patents

Description

Nov. 8, 1938.

F. L. GCRMLEYy LIFTING JACK Filed Dec. 14, l957 4 sheets-sheet 1 Nov. 8, 1938. F. L.. GORMLEY LIFTING JACK 4 Sheets-Sheet 2 Filed DeC. 14, 1957 Invenar:

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5f a s ,Frankl Go Nov., A8, l191%. F. L. GORMLEY LIFTING JACK Filed Dec. 14, 1937 I Jllllllllllllllll IIIIII II'IIIIII Nov. s, 193s. F, GO'RMLEY 2,135,938

LIFTING JACK Filed Dec. 14, 1957 4 sheets-sheet 4 'q'gl. A Flg .InvcnZ'o-r: E'ank L Gormley,

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Patented Nov. 8, 1938 UNITED STATES LIFTING JACK Frank L. Gormley,

The Buda Company, of Illinois Application December 14,

A18 Claims.

. 'This invention relates to ratchet lifting jacks and particularly to that `class known as automatic lowering jacks and which have two spring controlled pawls one for lifting the load and the other for holding the ram in raised position while the lifting pawl ismoving downwardly into position preparatory to another lifting operation.

One of the principal objects of the present invention is to produce a simple and effective device which is adapted to automatically change the direct operation of both the lifting and holding paw-ls from raising to lowering position or vice versa.

Another object of the invention is to have the jack so designed that the automatic device will be located in plain'sight of the operator and so distinctly marked asvto indicate the proper direction of movement of the reversing device for raising and lowering of the ram.

A further object of the invention is to construct the jack sothat the lifting pawl and holding pawl will be of the same size and interchangeable with each other, thus bringing about considerable reduction in, the cost of manufacture and reduce the number or" service parts.

And another object of the invention is to so construct the jack that three of its sides will have no obstruction thereon to prevent the use of a load lifting chain on either one of the three sides.

These objects are attained by the mechanism illustrated inthe accompanying drawings.

For the purpose of illustrating the invention, one preferred form thereof is illustrated in the drawings, this vform having been found to give satisfactory and reliable results, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized, and the invention is not limited to the precise arrangement and organization of these instrumentalities as herein shown and described except as required by the scope of the appended claims.

Of the drawings:

Figure 1 represents an elevation partly in section of a lifting jack embodying the principles of the present invention, the various parts thereof being in position for lowering the load.

Figure 2 represents a similar elevation partly in section showing the upper end of said lifting jack with the various parts in position for raising the load.

Figure 3 represents an elevation partly in section of the opposite side of said lifting jack.

Figure 4l represents an elevation of the two Brookline, Mass., assignor to Harvey, Ill., a corporation 1937, Serial No. 179,669

pawls of the jack and showing the means for normally moving them about their pivots into contact with the teeth oi the rack or ram.

Figure 5 represents a horizontal section of the jack on line 5, 5 on Fig. 3.

Figure 6 represents a horizontal section of the jacken line 6, 6 on Fig. 3.

Figure I represents a horizontal section of the jack on line `I, 1 on Fig. 3.

Figure 8 represents the plan oi a portion of the upper end of the lifting jack showing the reversing shaft and the locking lever secured thereto in the position assumed when the jack is raising the load.

Figure 9 represents a similar view with the locking lever in the position it assumes when the jack is lowering the load.

Figure l0 is an enlarged section of the reversing mechanism in the position assumed when the load is being lowered.

Figure 11 is a section of the same on line II, II on Fig. 10.

Figure l2 is an elevation of a modified form of the yielding member adapted to connect the projections on the two pivoted pawls when the load is being lowered, and

Figure 13 represents a side elevation of the same.

Similar characters indicate like parts throughout the several gures of the drawings. 30 In the drawings, I0 is the base of the jack and this base has extending upwardly therefrom a hollow casing II, from the upper end of which projects a handle I2 by which the jack may be carried from place to place. 35

As shown at IIa: the casing II is open at the front to give access to the operating mechanism.

This casing Il is provided at the top with a square bearing I3 through which extends the rectangular ram or rack I4, this rack having on the front side thereof a plurality of teeth I5.

The ram or rack I4 has secured to its upper end a supporting head I6 and at its lower end has formed integral therewith and projecting rearwardly therefrom another supporting member Il. Either the head I6 or the projection I1 may be used to support a load.

The projecting member I1 extends through a slot I8 in the rear wall I9 of the casing II.

The lower rear face of the ram I4 contacts with the lower inner face of this wall I9 as it reciprocates endwise therein, the teeth I5 of said ram being free from contact with the opposite wall 2l] of said casing Il.

Ribs I 53s contact with the opposite side walls of the ram I4 and prevent any lateral movement of the same during its endwise movement.

The ram I4 may be inserted through an opening 2l in the base II) and after such insertion the head I3 is secured to the upper end of the ram by means of the pin 22.

The opposite side walls of the casing II have openings therein to receive the oppositely disposed cup-shaped members 23 held in the side walls cf the casing I I by set screws 23x.

Disposed within these cup-shaped members 23 are trunnicns 24 projecting from the opposite sides of a member 25 provided with sockets 2511: either of which is adapted to receive an actuating lever 251 whereby said member 25 may be moved in either direction about the axis of said trunnions 24.

The walls of the casing II are so constructed that the trunnions 24 be disposed ever the ends thereof and form bearings therefor.

The inner end of the socketed member 25 is provided with a semi-cylindrical seat 25 to receive the cylindrical hub 21 of a lifting pawl 23 and one wall of said inner end is cut away as at 23x to permit the insertion of the pawl 28 from one side of the socketed member 25 with its cylindrical h`ub 21 disposed in the seat 2B.

The wall on the opposite side of the socketed member 25 is provided with a cylindrical bearing 21x to receive one end of the hub 21.

The pawl 28 is adapted to oscillate about the axis of hub 21 and at its upper end is provided with a plurality of teeth 29 adapted talengage the teeth i of the ram or rack I4.

Near the upper end of the casing II and integral therewith is a concaved seat 39 closed at one end by plate 39m.

Extending inwardly from the opposite end of said seat is a tubular member 3 I, a portion of the wall of which is cut away to permit the oscillation therein of the hub 32, the upper end of which has formed thereon a plurality of teeth 33 adapted to engage the teeth l5 of the ram or rack I4 and prevent the accidental lowering of the ram or rack I4.

The member 3l is held in position by means of a set screw 35 I.

To one side wall of the casing II is secured a headed stud 39 about which is coiled a spring 40.

One end of this spring 4B coacts with a side extension 4I formed upon the lifting pawl 28 while the opposite end of said spring coacts with a similar projection 4I.r on one side of the holding pawl 32, the tension of said spring 40 being such as to cause the ends thereof to spring away from each other.

The same spring 49 therefore tends, under normal conditions, to force the teeth of both of the pawls 28 and 32 into engagement with the teeth i5 of the ram or rack I4.

The socketed member 25 is provided with a downward projection 42 which is adapted to engage the shoulder d3 on the casing I I to limit the downward movement of said member, and another shoulder 43 on the casing I I limits the upward movement of said member 25.

The two sockets 25.1': are provided in order that different leverages may be obtained in the operation of the jack under varying conditions.

When the member 25 is moved downwardly under certain conditions the lifting pawl will raise the ram or rack I4, the holding pawl 32 being may be moved into posi-Y tion so that the cup-shaped members 23 mayV tension 50 forming a part 3M: of the holding pawl forced outwardly from engagement with the rack teeth I 5 against the tension of the spring 40, while the rack teeth I5 are passing the teeth 33 of said holding pawl 32.

As soon as the member 25 has reached the end of any of its downward movements, the spring 40 will force the teeth 33 of the holding pawl 32 into engagement with the rack teeth I5 and retain the rack I4 in position while the pawl 28 is being moved downwardly into a lower position preparatory to another lifting operation.

This is of considerable importance as with this Vtype of jack there has always been a tendency for the holding and lifting pawls 28, 32 to ily out of contact with the rack teeth I5 and allow said rack I4 and the load supported thereby to accidentally lower and thus cause serious accidents.

By providing a single spring 40 in the manner sho-wn and described both of the pawls 28, 32 at all times are retained in position to engage with the rack teeth I5 when, jack, it is necessary for the teeth of either pawl 28, 32 to engage the teeth I5 of the ram I4.

'I'he liftingV pawl 28 and the holding pawl 32 are exactly alike and either one may be used in place of the other. This reduces the cost of manufacture to some exten The lifting pawl 28 and the holding pawl 32 are both fulcrumed at their lower ends and extend upwardly from said fulcrums with the teeth 29 and 33 at the upper ends thereof.

The pawls 28 and 32 have arms 44, 45 extending rearwardly from one side thereof.

The arm 44 on the lifting pawl 28 has a lateral trunnion or projection 46 on which is mounted an annular member 41 having a radial extension 48, the periphery of which is groovedY to receive one end of a yielding helical spring 49.

The opposite end of this spring 49 is coiled about a helical groove in the periphery of an exof and extending downwardly from a U-shaped block 5I having a flat sided notch 5Irc therein, said block 5I being provided with a slotted upward extensionl 52 which encloses a reversing shaft 53.

'Ihe arm 45 on pawl 32 is provided with a lateral trunnion or projection 45x which is adapted to be disposed in the notch 5I1r when a load is being lowered.

The shaft 53 is rotatable in an elongated bearing 54 formedV in the casing I I and has secured to the outer end thereof an actuating `wing or lever 55 by which said shaft 53 may be rotated part way about its axis and also under certain conditions moved forwardly and then locked in its forward position by means to be described hereinafter.

The opposite or rear end of the reversing shaft 53 has a collar 56 secured thereto between which and the slotted extension 52 is a helical buffer spring 56x and between the rear end of the bearing 54 and the slotted extension 52 is a longer expansible spring 51 coiled about the reversing shaft 53, said spring 51 being adapted to be expanded during'the lowering of the load. When raising the load by the oscillation of the socketed member 25 with the teeth 29 of the pawl 28 in engagement with the teeth I5 of the rack or ram I4, the spring 51 will be'under compression and the wing 55 locked from turning, the slotted extension 52 at this time freely reciprocating vertically while enclosing the reversing shaft 53 without performing any operation.

When it is desired to reverse the movements of the lifting pawl 28 and holding pawl 52 prein the operation of the,

is f

l from engagement with the inclined locking notch 55|.

When thus unlocked 'the spring 51 is :free to expand .and its expansion will move vthe shaft 53 to .the rear and at the same time said expansion of :said lspring acting on the vslotted end 52 will nove the yielding member 49 into Ithe position shownfin Fig. l with the projection 45.1,' disposed inthe notch v|x, thus causing the pawls 28,132 to .beyieldingly connected together.

When the cam member 55x `of the wing 55 is engaged with shoulder 55| vthe reversing shaft 53 will be prevented from any movement in la rear- Ward direction and the rspring will be kept under compression until released.

When in the operation -of `the jack .it is desired to lower the load, Athe spring51 is permitted to expand and cause the extension 45m on the hold ing pawl 32 to enter the notch 5|:1: in block 5I, the spring 51 under expansion causing the spring 49 and its associated parts to move about its fulcrum 46 so vrthat the extension 45m willbe retained inthe notch 5m,` of the U-shaped block 5I during the lowering of the load.

When this has been accomplished it is obvious that 'thelifting pawl 28 and the vholding pawl 32 will'be connected together through the expansible spring v49 and the elements connected thereto, thereby permitting these pawls to operate alternately as holding pawls.

When the load `is being raised the reversing spring 49 will be in the position indicated in Fig. 2 of thevdrawings, the lower end of said spring being connected to the projection 46 on the lifting pawl28.

This reversing spring 49 is movable with the lifting pawl '28 and when a load is being raised floats freely in an upward and downward direction, the upper endthereof moving transversely of and being guided by the reversing shaft 53.

At this 'time the projection 45a.' of pawl 32 will befdisconnected from ythe U-shaped block 5I and the pawls 28, 32 will be disconnected from each other.

When Ait is desired to lower the load the reversring shaft wing 55 on the front side of jack is placed in position to permit the movement of the shaft 53 to the rear into the position shown in Fig. 1.

'This rearward movement will be effected by the expansion of the spring 51, which in its expansion will force the yielding reversing spring 49 into position to connect together both pawls 28, 32 preparatory to lowering the load.

Thediameter of the projection 445st is somewhat lessthan'the width of notch 5Ix so that there is some lost motion between the' two.

vOn the upward stroke of the socketed member 25 the reversing spring `49 will be drawndownwardand the surface A of the notch 5| :c in the U-shaped block y5| connected to the reversing spring 49 will come in contact with the projection 45a.` of the holding pawl 32.

The upward stroke of the socketed member 25 willthen continue until sufficient tension has been placed'on the reversing spring 49 to disengage the lifting pawl t28 from teeth I5 in the rack bar I4.

The socketed member 25 will then be operated inla'idownwarddirection and while being operated in this direction the reversing spring 49 will be 'raised andthe surface :C ofthe lil-shaped block 5| will "come into vcontact with the :lower .side :fof the projection 45a: on the holding :pawl "32.

This vdownward Vstroke of 'the vsocketed member 25 will lcontinue iuntil vsufficient tension .has been placed on the Areversing spring 49`to1disengagethe holding pawl 32 from the teeth vI5 in the rack bar I4.

After the holding pawl 32 has 4been releasedfrom the teeth `I 5 in the rack bar `If4,` the socketed member 25 will be operated 'in the upward direction, thus allowing the load to lower until Lthe holding pawl 32 contacts with another "toothfin the rack bar I4.

The lowering of the load in this :manner may continue so long as the :reversing shaftwng l55 is in .its unlocked position and the 1socketed-member 25 is operated in an upward 4and downward direction.

In lifting jacks of thischarac'ter two pawls are always utilized, one being a :lifting pawl '.28 to raise a load, while the other such 'as 32 *is the holding vpawl to hold the load during the `raising operation.

In the present device when lowering the .load the operation ofthe pawl '28 may be Vreversed so that it .may act as a holding pawl while the pawl 32 is being movedinto a new position preparatory to a further engagement with 'the kteeth I5 o'f ram I4.

In the present device the'pawl 28 fknown as 4the lifting pawl is connected to and operatedby ythe socketed member 25 fulcrumed on the .main jack frame or casing while 'the fulcrum of the 'other pawl 32 or holding pawl is mounted in a tubular member 3| disposedon aaseat 30 which is a part of'said main frame or casing.

When the jack is used to raise a .load the lifting pawl 28 is operated by the socketed member 25 and will raise the'rack bar v'I4 fa certain -distance, this distance depending on 'how Amuch off center the fulcrum 2:1 of vthe lifting pawl 28 -is located from the fulcrum center -23 of the'so'cketed member 25.

The rack bar |4 is raised in this lmanner so that the teeth I5 will pass over the 'teeth `33 of the holding pawl 32.

This holding pawl 32 will hold Ithe load while another upward stroke of the socketedmember25 is being made, v.preparatory to further lifting of the load.

When the load is to be lowered Vthe reversing leverf55 is turned 4clockwise to disengage vthe cam member 55a: from the locking notch 55| y-so that the lifting pawl 28 and holding'pawl 32 will lbe connected together and the operation of the lifting pawl 28 will ybe reversed, said pawl 28 Aacting as an additional holding pawl while v'the load is being lowered.

Obviously, it is quite necessary for the lifting pawl 28 to move upward clear of the rack teeth |.5 while the holding pawl 3-2 supports the load.

Near the end of its .upward travel vthe lifting pawl 28 will engage the rack teeth I5 and raise the rack I4 sufciently to release .the `load from the holding pawl 32.

The holding pawl 3.2 `will then move Aclear of the rack teeth and allow the load `to be lowered while supported by the lifting pawl 28, which yis being moved by the socketed member 2.5.

The holding pawl -28 will comezintoiproper position to hold the load when the .requireddis'tance downwardly of the rack I4 has vbeen. reachediin the lowering operation.

This .operation :may be repeated :by .-operating the socketed member 25 until the load has been lowered the requireddistance.

After this has been accomplished, by turning the reversingl lever 55 into its locked position with spring 51 compressed and then operating the socketed member 25 as previously stated, the pawls 28 and 32 will be disconnected and operate inthe usual manner to raise the load.

The casing has an opening 58 extending therethrough to form a handle by which the jack lmay be moved from place to place.

When the two pawls 28 and 32 have been connected in the manner described, the load may be automatically lowered.

In the present jack the control for reversing the operation of the pawls is located at the front of the jack wherey it can be plainly seen and this control is also plainly marked so that the operator can tell in just what direction the ram i4 will operate either in raising or lowering a load, thereby avoiding accidents in operating. Y

It will be noted that in the present device the load may be raised or lowered on three sides of the jack by using chain lifts if necessary without any obstruction from the side of the jack to prevent the raising or lowering of the load.

In lifting by chains the. links of the chains are disposed in the slots S0 of head I6.

The casing Il is provided on one side with an arcuate flange Bi partially surrounding the lever or wing 55 and preventing it from being moved accidentally.

The spring 49, block 5I Yand member 41 form a yielding connection between the pawls 28 and 32 during the lowering of the load.

If desired, the yielding connection may be made of a single wire 62 of spring steel as shown in Figs. 12 and 13.

This modified form of yielding connection has at its lower end a loop 41:1: through. which the projection 46 of pawl 28 extends and near itsy upper end is bent U-shaped as at 55x to form a notch 4|:c to receive the projection 45:6 of the holding pawl 32.

Between the loop 47x and notch 5|:c the wire 62 has coils 49:12 therein forming a yielding spring connection between said loop 41:1: and notched portion 40a'.

Above the notched portion 40x the wire 62 extends upwardly and downwardly over the reversing shaft 53 as indicated at 52x.

This upward extension 52:1: straddles the shaft 53 and is movable transversely thereof between the springs 56x and 51.

Opposite the yielding member 49 or 62, the casing I I has an opening 63 in one wall thereof normally closed by a plate 63a: which may he removed to give access to said yielding member.

It is believed that the operation and many advantages of the invention will be understood without further description.

Having thus described my invention, I claim:

-1. A ratchet lifting jack consisting of a vertically movable rack having a plurality of rack teeth; a lifting pawl; a holding pawl; means for oscillating said lifting pawl; a yielding member supported on said lifting pawl and movable therewith; and means for connecting the upper end of said yielding member to the holding pawl preparatory to the lowering of the load.

2. A lifting jack as set forth in claim 1 in which the lifting pawl and the holding pawl are alike and interchangeable.

3. A lifting jack as set forth in claim 1 in which said yielding member includes a U-shaped block; a projection on the holding-pawl adapted to coact with said U-shaped block; and means for retaining said projection in the notch of said block during the lowering of the load.

4. A lifting jack as set forth in claim 1 in which said yielding member includes a U-shaped block; a projection on said holding pawl adapted to Coact with'said Lil-shaped block; and spring controlled mechanism for retaining said projection in the notch of said block during the lowering of the load. 1

5. A lifting jack as set forth in claim l in which the yielding member is formed of a single wire having a loop at one end adapted to coact with the lifting pawl, a notch to ooact with a projection on the holding pawl, and coils under spring tension between said notch and loop.

6. A lifting jack as set forth in claim 1 in which said yielding member includes a notched block; a projection on the holding pawl adapted to coact with the notch of said block but disengaged therefrom during the lifting operation; and means for forcing said projection into the notch of said block and retaining it therein during the lowering of the load. Y

j 7. A lifting jack as set forth in claim 1 in which said yielding member includes a coiled spring and a notched block mounted on the upper end of said spring and having a slotted'upper end; a projection on said holding p awl adapted to be forcedinto the notch of said block but disengaged therefrom during the lifting operation; a reversing shaft extending through said slot; and spring controlled mechanism coacting with said shaft for forcing said projection into the notch of said block and retaining it therein during the lowering of the load.

8. A lifting jack as set forth in claim 1 in which said yielding member includes a coiled spring and a notched block mounted on the upper end of said spring and having a slotted upper end; a projection on said holding pawl adapted to be forced into the notch of said block but disengaged Vtherefrom during the lifting operation; a reversing shaft extending through said slot; an expansible spring surrounding said shaft and bearing against said slotted end; means foi retaining said spring under compression during the liftingA operation; and means for releasing said spring and retaining it expanded during the lowering of the load. V

9. A lifting jack as set forth in claim Y1 in which said yielding member includes a coiled spring and a notched block mounted on the upper end of said spring and having a slotted upper end; a projection on said holding pawl adaptedrto be forced into the notch of said block but disengaged therefrom during the lifting operation; an oscillatory reversing shaft extending through said slot; an expansible spring surrounding said shaft and bearing against one side of said slotted end; means at one end of said shaft for moving it forward and locking it in adjusted position; and means on the opposite end of said shaft and bearing against said forked end adapted to compress said spring during the forward movement of the shaft.

10. A lifting jack as set forth in claim 1 in which said yielding member includes a coiled spring and a notched block mounted on the upper end of said spring and having a slotted upper end; a projection on said holding pawl adapted to be forced into the notch of saidblock but disengaged therefrom during the lifting operation; an oscillatory and reciprocable reversing shaft extending through said fork; an expansible spring surrounding said shaft and bearing against one side of said slotted end; a collar secured to the rear end of said shaft; a buffer spring between said collar and the opposite side of said slotted end; and a cam lever on the forward end of said shaft for moving it forward to compress the spring during the lifting operation and to subsequently release said spring permitting it to exp-and and force the projectionA of the holding pawl into the notch of said block and retain it in engagement therewith during the lowering of the load.

11. A ratchet lifting jack consisting of a vertically movable rack having a plurality of rack f' teeth; a lifting pawl; a holding pawl; a projection on the side of each pawl; means for oscillating said lifting pawl; a yielding member pivotally mounted on the projection of the lifting pawl and movable therewith and provided with a notch near its upper end to receive the projection of the holding pawl thereby providing a connection between said pawls and causing them to alternately engage the rack teeth during the lowering of the load; and means for controlling the engagement and disengagement of said projection with the notch of said yielding member.

12. A lifting jack as set forth in claim 11 in which the projection on the holding pawl has a diameter slightly less than` the width of said notch.

13. A ratchet lifting jack consisting of a vertically movable rack having a plurality of rack teeth; a lifting pawl; a holding pawl; a projecltion on the side of each pawl; means for oscillating said lifting pawl; a yielding member pivotally mounted on the projection of the lifting pawl and movable therewith, said yielding member having near its upper end a notch with parallel sides adapted to receive the projection on said holding pawl; and means for retaining said holding-pawl projection in said notch during the lowering of the load.

14. A lifting jack as set forth in claim 13 in which the means for retaining said holdingpawl projection in said notch includes an ex-I pansible spring.

15. A lifting jack as set forth in claim 13 in which an 4expansible spring is provided to force said holding-pawl projection into said notch and retain it in said notch during the lowering of the load; and means for locking said spring under compression during the lifting of the load.

16. A lifting jack as set forth in claim 13 in which said yielding member has a slotted upper end; a projection on said holding pawl adapted to be forced into said notch but is disengaged therefrom during the lifting operation; a reversing shaft extending through said fork; and spring controlled mechanism on said shaft for forcing said holding-pawl projection into the notch of said block and retaining it in engagement therewith during the lowering of the load.

17. A ratchet lifting jack consisting of a vertically movable rack having a plurality of rack teeth; a lifting pawl; a holding pawl; a projection on the side of each pawl; means for oscillating said lifting pawl; a yielding member supported on said lifting pawl and during the lifting operation movable therewith independently of the holding pawl; and reversing means operable to connect the upper end of said yielding member with the projection of the holding pawl during the lowering of the load.

18. A ratchet lifting jack as set forth in claim 17, in which a casing enclosing said mechanism has three fiat sides free from obstruction whereby a lifting chain supported by the head of `said rack may be used on either of said sides.

FRANK L. GORMLEY.

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