US1389355A - Lifting-jack - Google Patents

Description

J. L. HEROLD LIFTING JACK.

APPLICATION FILED AUG.16, 1920.

Patented Aug. 30, 1921. 2 SHEEYSSHEET l- UNITED STATES PATENT OFFICE.

JAMES L. HERoLnor s'r. Louis, MISSOURI.

LIFTING-JACK.

Application filed August 16, 1920. Serial No. 403,970.

To all whom it may concern Be'it known that I, JAMES L. I-InRoLn, acitizen of the United States of America, a resident of the city of St. Louis and the State of Missouri, have invented certain new and useful Improvements in Lifting-Jacks, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

This invention relates to improvements in lifting j acks, one of the objects being to provide a reversible jack having a strong,

simple and positively acting reversing device which permits downward movement of the load supporting member in response to movements of the operating handle. A further object is to produce a jack of this kind in which the vertically movable load supporting member can be instantly lifted to its load supporting position, and thereafter permitted to drop instantly when it is re lieved of the load.

Another object is to produce a strong and simple jack having two'racks and two pawls, the pawls being movable alternately so as to elevate the load in response to each stroke of the operating handle. Some of the minor features of the invention lie in the combination of the racks, pawls and other details of construction combined in a particular mannor to form a very substantial support for the load-and at the same time permit easy operation of the operating handle.

A further object is to provide a simple lifting stirrup adapted to be easily and quickly applied to and removed from the vertically movable part of the jack.

With the foregoing and other objects in view, the invention comprises the novel construction, combination and arrangement of parts hereinafter more specifically described and illustrated in the accompanying draw ings wherein is shown the preferred embodiment of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications which come within the scope of the claims hereunto appended.

Figure I is a side elevation of a lifting jack constructed in accordance with this in vention. Fig. II 18 a vertical section taken approximately through the center of Fig. I.

Fig. III is a horizontal section on the line IIIIII,' Fig. I.

Fig. IV is a perspective view of the removable lifting stirrup.

Fig. V is a view similar to Fig. I showing the reversing cam positioned to provide for a downward movement of the jack.

'Fig. VI is a view similar to Fig. V, showing the pawls and operating lever in different positions.

Fig. VII is a view of the lower portion of the jack, illustrating a modification of the safety link whereby the pawls are connected.

A designates a stationary upright column comprising a vertical web 1 and flanges 2 and 8 extending from the side edges of said web, said flanges being provided with rack teeth 2 and 3' whereby vertical racks are formed on oppositely disposed side faces of the stationary column. A base 4 is formed integral with the stationary column.

B designates a vertically movable column comprising a pair of legs 5 straddling the web 1 and confined between the flanges 2 and 3, a head 6 being integrally connected to the upper ends of said legs, and loops 7 being formed integral with the lower ends thereof. The-loops 7 extend around the flanges 2 and 3, as shown by Figs. I and III. A seat 8 is ivotally'mounted on the top of the movable column, and this seat is adapted to receive axles and the like of different shapes. To attach the movable column B to the stationary column A, a long vertical slot 9 is formed in the web 1 of the stationary column, as shown by Figs. I and II and the movable column is provided with a bolt 10 which lies in this slot. To frictionally unite the columns when the movable column occupies its lowermost position, the lower end of web 1 is wedge-shaped as shown at 1" in. Fig. II, and this wedge-shaped portion is engaged by the lower ends of legs 5 on the movable column.

C designates an operating lever having a forked endstraddling the upper end of the movable column and connected thereto by means of a pivot pin 11 which lies directly above the slotted web l of the stationary column, A socket 12 is formed at the free end of the operating lever to receive a suitable operating handle.

A pair of fulcrum pins 13 are located in the forked end of the operating lever at points directly above the vertical racks on the stationary column. Pawls 14, depending from fulcrum pins 13, are adapted to enga the teeth of the vertical racks. These pawls are almost equal in length to the movable column, and their lower ends are adapted to engage the rcks while their upper ends are pivotally supported by the fulcrum pins 13 in vertical alinement with the racks. By arranging the pawls, fulcrum pins, and racks in this manner I provide a very substantial support for the load and at the same time avoid undue friction between the columns when the operating lever is actuated to raise or lower the movable column.

D designates controlling or governing triggers loosely mounted on the fulcrum pins 18 and connected together at their lower by means of a tension spring 15. These triggers are slotted to receive pins 16 which extend from the pawls 14.

WVhen the parts occupy the position shown by Figs. 1, 11 and 111, the spring 15 forces the triggers D into engagement with the pins 16, thereby yieldingly forcing the lower ends of pawls 142 into engagement with the racks 2 and 3' respectively. The movable column B can then be instantly lifted by hand until the seat 8 engages the load, and thereafter, the operating lever may be actuated to elevate the load. It will be readily understood that the operating lever C can be oscillated on its pivot 11 with the result of elevating the movable column B, and at the same time lifting the pawls and the operating lever which travel with the movable column. When the operating lever C is forced downwardly, the pawl 14: at the right hand side of Fig. 1 remains in contact with the race 2 and the fulcrum pin 13 at the upper end of said pawl serves as a fulcrum for the operating lever, the fulcrum being very close to the pivot 11 whereby the lever is connected to the movable column. While the lever 12 is moving downwardly, the pawl 14- at the left side of Fig. I is elevated to engage a higher tooth on the rack 3. Thereafter, it the operating lever C is forced upwardly, the pawl 14 at the right hand side of I will be elevated while the other pawl will remain in engagement with its raclr 3, and at this time the lever will be fulerumed on the pin 13 at the left side of Fig. I. From the foregoing it will be understood that the movable column is elevated one step in response to each stroke of the operating lever, and this step may he a distance equal to the length of ither one or two of the rack teeth. During the lifting operation, the spring 15 cooperates with the pivotally supported triggers D to retain the pawls in engagement with the racks, but a very different condition exists when the partsare positioned for a downward movement of the movable column.

1 will now describe the reversing means whereby the movable column is permitted to drop either instantly or step by step in response to movements of the operating lever. 17 designates springs coiled around pins 18 ends which project from the inner faces of the triggers D, the lower end of each spring 17 engaging a pin 16 on a pawl 14, while the upper end ,of each spring 17 bears against the hub on a trigger D The springs 17 are tensioned in such a manner that they tend to retain the pins 16 in engagement with the triggers D, said springs forming yielding connections between the triggers and the pawls. However, these springs 17 perform no function during the lifting operation when the spring 15 is effective. During the last mentioned operation, the triggers D oscillate with the pawls and the springs 17 merely tend to retain the triggers in engagement with pins 16 on the pawls.

A reversing cam 19, located between the triggers D, is loosely mounted on the pivot pin 11 and integrally connected to an operating handleQO as shown in Figs. 1 and II. The operating handle 20 lies outside of the housing 21 (Fig. 11) which incloses thereversing cam 19 and the triggers D.

By operating the reversing handle 20 the reversing cam 19 may be shifted from the position shown in Fig. I wherein it does not interfere with trigger D to the position shown in Fig. V wherein it serves as a spreader between the triggers D. When the reversing cam is shifted in this manner, it forces the triggers D away from each other, thereby stretching the spring 15 and separating one or both of the triggers from the pins 16 on the pawls. In this event, it is possible for triggers D to engage pins 16 as will be hereafter pointed out, but the spring 15 will not force the pawls toward each other, However, at the end of downward movement of a pawl the spring 15 forces the pawl into engagement with the rack.

The reversing cam 19 is free to turn on the pivot pin 11, and said cam merely consists of two fingers, one of which is adapted to enter a recess in a trigger D as shown in Fig. V thereby serving as adetentfor retaining the cam in its reversing position. When the cam 19 is positioned as shown in Fi V the spring 15 tends to force the triggers D into engagement with the cam, while the springs tent to disengage the pawls from the racks.

To provide for a step by step downward movement of the pawls and the movable column, I have shown a stop device which guides the pawls and limits their outward movements when the springs 17 are effective. .ln the preferred form of the invention, this stop device is a safety link F loosely mounted on a pivot pin 21 extending from one side of the movable column, said link having slots 22 formed in its ends to receive pins 23 which project from the pawls. The link F thus pivoted to the movable column B so as to travel with said column. It is to be shown by Fig.

understood that the pawls 14 are connected to the movable column through the medium of the operating lever.

The link F is secured to pins 23 at one side of pawls 14 and at the opposite side said pawls are provided with guide wings 24 (Figs. II and III). The wings 24 and link F are adapted to engage opposite sides of the stationary column A to prevent undue lateral displacement of the loosely mounted pawls. I

Figs. V and VI illustrate different positions which the parts occupy when the movable column is permitted to move downwardly in response to movements of the op erating lever C. Assuming that a load is supported by the movable column, the pawl 14' at the right side of Fig. V will be held in frictional engagement with one of the rack teeth 2, and the other pawl will be disengaged by the action of a spring 17 tending to throw the pawl away from the rack. The outward movement of the last mentioned pawl is limited by pin 23 at the lower end thereof, said pin coiiperating with slotted link F as shown in Fig. V. Under these conditions, if the operating lever G is permitted to move upwardly, the pawl 14 at the left side of Fig. V will move downwardly, and during the first part of this I downward movement it will be guided by the link F. Thereafter, as the said downward motion continues, the trigger D at the left side of the jack will engage pin 16 near the upper end of the downwardly moving pawl so as to force said pawl into engagement with the rack 3 as shown in Fig. VI. When the downwardly moving pawl reaches the position shown by Fig. VI, the cam 19 will be separated slight distance from trigger D at the left side of the jack, and the spring 15 will then tend to retain the left pawl in engagement with rack 3. Fig. V illustrates the positions of the parts at the beginning of the downward movement of the left pawl 14, and Fig. VI illustrates the positions at the cndof this movement. At the be -inning of said movement,a spring 17 releases the pawl from the rack and the outward movement of the pawl is limited by link F. To understand the action at the final part of this movement when a trigger D engages pin 16 to force the pawl onto the rack, it should be understood that the triggers D are loosely supported by fulcrum pins 13 while the re versing cam 19 isloosely supported on pivot pin 11, and that the spring 15 will tend to retain the triggers in engagement with cam 19. Therefore, a trigger D moving with the operating lever C, is capable of cooperating with a'pin 16 to force a pawl 14 into engagement with the rack. v

When the parts have reached the positions VI a continued downward movement may be obtained by first lifting the operating lever a very slight distance, so as to relieve the load from the pawl 14 at the right side of Fig. VI, thereby permitting a spring 17 to disengagesaid pawl. Thereafter, the operating lever is lowered and the last mentioned pawl moves downwardly un til it is forced into engagement with the rack by the action of trigger B at the right side of Fig. VI which finally engages the adjacent pin 16 to force the downwardly moving pawl into engagement with the rack.

From the foregoing it will be understood that the moving column will move downwardly in response to each stroke of the operating handle when the reversing device is effective. Each downward step is preferably equal to the len th of two rack teeth. lVhen there is no load on the c i l movable column, said column and the 1 rts carried thereby may be dropped instantly when the reversing device ffective. This is accomplished by merely lii' the 21101;- able column a slight distance to release both pawls from frictional enga ement with the racks, thereby permitting sp 1? to throw both pawls away from tl: cl; tee-Eb.

G designates a removable lifting stirrup which is shown in Figs. I, H and IV. The movable column is provided with pairs of oppositely disposed abutment pins 30 (F and projecting from its side faces. Thelifting stirrup G extends laterally from the movable column and it is provided with legs 3.1 which straddle said column, said legs being seated on two of the projectmg ab'utments 30 and provided with upwardly extending feet 32 w--ich engage two abutments 30 at a higher elevation. As shown in Fig. I the legs 31 are recessed at their lower edges to provide curved sides which engage the upper portions and the left side of the lower pins 30, while the feet ergage the right side of the upper pins 30. The stirrup isthus detachably inte locked with the movable column and it can be very easily and quickly applied to and removed from said column.

In Fig. VII I have shown a modification wherein pawls 14 are connected by a linl: F which is similar to the link F. However, the link F is not attached to the movable column B. Pins 23 extend from the pawls 14 and pass through the link F said link having a round hole adapted to receive one pin 23 and the slot 22 adapted to re ceive the other pin. Instead of being long enough to permit release of both pawls, at the same time, the slot 22 is preferably relatively short so as to permit release of only one pawl at time. This link F may be used instead of the link F and when so used it will cooperate with the other elements of the reversing device herein described to permit a step by step upward and downward movement of themovable column, the

links serving to limit the outward movements of the pawls.

I claim:

1. In a lifting jack, a stationary column provided with a pair of racks, a movable column, an operating lever pivoted to said movable column, a pair of pawls adapted to engge said racks, fulcrum members connecting said pawls to said ope ing lever, yielda )lQ engaging means tending to ensaid pawls with said racks, yieldable disengaging m s-ins, including sp-ing memepted to disengage said pawlsi rom rsing device whereby said 1 111g means released from to permit a yieldabie div aging means, and a device whereby movements voi pawls are limited when they are actuated by said yield ble is 1". 'a;.-;i11 means.

in a lifting sta provided with a raclrs, a movable (,Ollll'ilil, an {ngerating lever pivoted to said movable colt nn, a

to en sai raclrs, fulcrum nnb rs connectin said pa'wls to said operatnig' lever,

yieldable eng ging means tending to ei said pa ls with said 1' clrs said yielcengaging means comprising triggers carried by said operating lever and a spring cooperating with said triggers to force said pawls into engagement with said racks, and yieldable disengaging means comprising spring members adapted to disengage said pawls "from the vice whereby said triggers are actuated to render said engaging means ineffective.

3. In a lititing jack, a stationary column provided with a pair of racks, a movable column, an operating lever pivoted to said movable column, a pair of pawls adapted to engage said racks, fulcrum members connecting said pawls to said operating lever, yieldable engaging; means tei'iding to engage said pawls with said racks, said yieldab le engaging means comprising sprin actuated triggers pivoted to said operatic lever and engaging parts of said pawls to force said pawls into engagement with said racks, and yieldable disengaging means comprising spring members adapted to disengage said pawls from said racks and a reversing cam whereby said triggers are released to permit effective operation of said spring members.

l. In a lifting jack, a stationary column provided with a pair of racks, a movable column, an operating lever pivoted to said movable column, a pair of pawls adapted to engage said racks, fulcrum members con necting said pawls to said operating lever, yieldable engaging means tending; to engage said pawls with said racks, said yieldable engaging means comprising a pair oi spring actuated triggers pivoted to said operating lever and a tension spring connectracks and a reversing de-' ing said triggers to pull them toward each other, said pawls having 'abutments engaged by said triggers to force the pawls into engagement with said racks, a reversing cam carried by said operating lever and adapted to force said triggers away from said a-butments, and yielding means adapted to force saidpawls away from said racks when said reversing cam is effective.

5. In a lifting jack, a stationary column provided with a pair of racks, a movable column, an operating lever pivoted to said movable'column. a pair of nawls adapted to engage said racks, fulcrum members connecting said pawls to said operating lever, yieldable engaging means tending to engage said pawls with said racks, said yieldable means comprising a pair of spring actuated triggers pivoted to said operating lever and a tension spring connecting said triggers to pull them toward each other, said pawls having abutments engaged by said t iggers to force the pawls into engagement wi 11 said racks, a reversing cam carried by said operating lever and adapted to force said triggers away from said abutn'ients, and yielding means adapted to force said pawls away from said racks when-said reversing cam is effective, said triggers being movable with said operating leverso as to alternately said abutments and thereby actuate said pawls while the reversing cam 1s effective.

6. In a lifting jack, a stationary upright column providedwith a pair of racks with outwardly facing teeth on its opposite sides, a movable column interlocked with said stationary column, an operating lever pivoted to the upper end of said movable column, a pair, of fulcrum pins carried by said operating lever and located above said racks, a pair of pawls depending from said fulcrum pins and adapted to engage said racks, a pair of triggers pivoted to said operating lever, said pawls having abutments adapted to be engaged by said triggers, a

spring connecting said triggers to force them ontosaid abutments, thereby forcing said pawls into engagement with said racks, spring members adapted to disengage said pawls from the racks, a reversing cam whereby said triggers may be forced apart to prevent effective operation of the connecting spring, thereby permitting opera tion of said spring members, and a stop device whereby movements of said pawls are limited when they are actuated by said spring members. i

7. In a lifting ack, a stationary column, aim'ovable column, an operating lever pivoted to one of said columns, the other column being provided with a pair of oppositely disposed racks, a pair of pawls pivoted to said operating lever and adapted to engage said racks, said operating lever being said yielding means.

8. I11 a lifting jack, a stationary column, a movable column, an operating lever pivoted to one of said columns, the other column being provided with a pair of oppositely disposed racks, a pair of pawls pivoted to said operating lever and adapted to engage said racks, said operating lever being movable on its pivot to alternately adv vance the pawls along the. respective racks,

yielding means adapted to disengage the pawls from the racks to provide for reversal. of the movement of said movable column, and a stop device comprising a safety'link loosely connecting said pawls to limit move ments thereof when they are disengaged by said yielding means.

9. In a lifting jack, a stationary column, amovable column, an operating lever pivoted to one of said columns, the other column being provided with a pair of oppositely disposed racks, a pair of pawls piv oted to said operating lever and adapted to engage said racks, said operating lever being movable on its pivot to alternately ad Vance the pawls along the respective racks, yielding means, including a spring, adapted to automatically disengage the pawls from the racks to provide for a reversal of the movement of said movable column, and a stop device comprising a connecting link having its ends loosely pivoted to said pawls so as to limit movements of said pawls when they are disengaged bysaid yielding means.

10. In a lifting jack, a stationary column a movable column, an operating lever pivoted to one of said columns, the other column being provided with a pair of oppositely disposed racks, a pair of pawls pivoted to said operating lever and adapted to engage said racks, said operating lever being movable on its pivot to alternately advance the pawls along the respective racks, yielding means, including a spring, adapted to automatically disengage the pawls from the racks to provide for a reversal of the movement of said movable column, and a stop device whereby said pawls are guided along said racks when said yielding means is effective, said stop device comprising a link and pivots loosely connecting said link to said pawls, said pivots serving as stops to limit movements of said pawls when the latter are disengaged by said yielding means.

11. In a lifting jack, a stationary column,

yielding amovable column, an operating lever pivoted to one of said columns, the other column being provided with a pair of oppo sitely disposed racks, a pair of pawls piv' oted to said operating lever and adapted to engage said racks, said operating lever being movable on its pivot to alternately advance the pawls along the respective racks, means, including a spring adapted to automatically disengage the pawls from the racks to provide movement of said movable column, and astop device whereby said pawls are guided along said racks when said yielding means is effective, said stop device comprising a link pivoted to the column to which the operating lever is pivoted, and pivots loosely connecting said link to said pawls, the last mentioned pivots being adapted to stop and guide said pawls when said yielding means is efiective.

l2. In a lifting jack, a stationary upright column provided with a pair of racks with outwardly facing teeth on its opposite sides, a movable column interlocked with said stationary column, an operating lever pivoted to the upper end of said movable column, a pair of fulcrum pins carried by said op erating lever and located above said racks, a pair of pawls depending from said fulcrum pins and adapted to engage said racks, yielding means tending to force said pawls into engagement with said racks to provide for upward movements of said pawls and movable column in response to movements of said operating lever, and reversing means cooperating with said pawls to provide for a reversal of the movement of said movable column, said reversing means comprising spring members ten'ding to disengage said pawls from the racks and a stop device whereby said pawls are guided along said racks when said spring members are effective, said stop device including a link pivoted to said movable column, and pivots loosely connecting said link to said pawls, the last mentioned pivots being adapted to stop and guidesaid pawls when said reversing means is effective.

13. In a lifting jack, a stationary upright column comprising a vertical web and flanges extending from the side edges of said web, said flanges having teeth in the form of vertical racks on their outer faces, a movable column straddling said web and confined between said flanges, an operating lever having a forked end straddling and pivoted to the upper end of said movable column at a point above said web, a pair of fulcrum pins located in said forked end at polnts directly above said racks, a pair of pawls depending from said fulcrum pins and adapted to engage said racks, yielding means tending to force said pawls into engagement with said racks to provide for upfor a reversal of theward movements of said pawls and movable column, and reversing means cooperable with said operating lever to alternately disengage said pawls from the racks, said columns being provided with cooperating wedging faces whereby they are frictionally united when the movable column occupies its lowermost position.

14. A lifting jack provided with a movable column having projecting abutments on its side faces, operating means whereby said movable column is elevated, and a lifting stirrup extending laterally from said movable column and provided with legs straddling said movable column and removably interlocked with said abutments.

15. A lifting jack provided with a movable column having pairs of oppositely disposed projecting abutments on its side faces, operating means whereby said movable column is elevated, and a removable lifting stirrup extending laterally from said movable column and provided with legs straddling said movable column, said legs being seated on two of saidoppositely disposed projections and provided with upwardly extending feet engaging two of said projections.

In testimony that I claim the foregoing I hereunto affix my signature.

JAS. L. HEROLD.

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