US2632629A - Pawl actuated cable lift - Google Patents

Description

Mi 1953 G. c. M-ONCKMEIER 2,632,629

PAWL ACTUATED CABLE LIFT Filed- July 12, 1950 a Sheets-Shee t 1 INVENTOR.

March 24, 1953' G- c. MONCKMEIER' 2,632,629

PAWL ACTUATED CABLE LIFT Filed July 12, 1950 sshens-sheet 2 I i 1 i gszzw afifoneimezr \\\\Y I gig lllll I March 24, 1953 r e. c. MONCKMElE 2,632,629

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t E nckmezer Patented Mar. 24, 1953 UNITED STATES PATENT OFFICE PAWL ACTUATED CABLE LIFT Gustav G. Monckmeier, Davenport, Iowa Application July 12, 1950, Serial No. 173,289

Claims. 1 The present invention relates generally to hoists or jacks, but more particularly to a novel and improved type of mechanical jack.

One of the objects of the present invention is to provide a novel and improved simplified jack having means embodied therein whereby the downstroke of the operating lever raises the object being lifted and the upstroke of the lever serves as an energy storing stroke or counter balance.

A still further object of the invention is to provide a novel and improved lifting jack in which substantially all the parts are made of heavy sheet steel so as to simplify the construction and economize on the material being used.

A still further object of the invention is to provide a lifting jack in which the lifting member thereof has associated therewith a cable which is trained about a pulley carried by the lift ratchet member so that the object being lifted is raised a distance of substantially twice the distance that the lift member is extended beyond the main frame.

These and other objects are accomplished by providing a construction and an arrangement of the Various parts in the manner hereinafter described and particularly pointed out in the appended claims.

Referring to the drawings:

Fig. 1 is a side elevational view with portions of the jack removed for the purpose of showing some of the operating parts thereof;

Fig. 2 is a fragmentary cross sectional view taken on the lines 22 in Fig. 1;

Fig. 3 is an enlarged fragmentary side elevational view partly in cross section with the pawls in position to normally raise the ratchet standard or lift member;

Fig. 4 is an enlarged fragmentary view partly in cross section showing the cam lever in position to lower the jack;

Fig. 5 is a cross sectional view taken on the lines 5-5 in Fig. 4; and

Fig. dis a cross sectional view taken on the lnes 6-6 in Fig. 2. In illustrating one form. my improved jack may assume in practice, the same comprises a main or horizontal base frame member It in the form of an inverted channel which is adapted to be mounted and supported ona relatively smaller channel member II to the outer ends of which are secured spaced apart vertically depending supporting legs H. The upper ends of the legs II are welded to the channel bracket member I2. (See Fig. 6 of the drawings.) Welded to the center of the channel base member Ill and on the top side thereof is a hollow extension at the upper end thereof as shown at l5 which is substantially square in cross section with the forward portions slightly curved or bowed as shown at I6. The housing 13 has opposite and spaced apart parallel side walls I 3. Telescopically or slidably mounted in the extension 15 and within the housing I3 is a vertically adjustable and hollow ratchet or lifting member [1. This lift member 17 extends downwardly and is adapted to move through an opening [8 in the base member Ill between the vertically spaced apart legs ll of the jack. The ratchet or lift member l'l may be of any desired length and is guided in the lower portion of the housing [3 by a transverse or curved guide strap [8 which has its opposite ends welded to the opposite side walls [3' of the housing member [3. The forward curved vertical surface of the ratchet or lifting member IT has a plurality of uniformly spaced apart ratchet teeth l9. Cooperating with the ratchet teeth IQ of the lift or ratchet member I1 is a holding pawl, generally indicated by the reference character 20. The pawl 20 is of channel-like formation and has its opposite sides or flanged portions 64 pivoted on a pin 2| which, in turn, extends through aligned apertures 22 in the opposite side walls l3 of the housing member 13. (See Fig. 5 of the drawings.) The upper or free end of the pawl 20 has a transversely extending pointed tooth engaging portion as shown at 23 which is adapted to engage the ratchet teeth It of the ratchet or lift member ll. The pawl 29 is normally pressed into engagement with the teeth by a flat curved spring 24 which has one of its ends secured to the inner side of the pawl by a rivet 25. The other end of the spring 24, as shown at 26, is adapted to engage the inner curved surface M of the housing l3 as shown in Fig. 4 of the drawings. A hand operating lever of hollow or channel-like construction, generally indicated by the reference character 21, is pivoted to a transverse pin 28. The pin 28 extends through aligned apertures 29 in the opposite side walls I3 of the housing [3. The free end of the operating lever 21 projects through an arcuate opening 30 in the forwardly bowed portion M of the housing l3 as clearly shown in Fig. 4 of the drawings. The pin 28 is retained in position by suitable cotter pins 3!. Pivoted to the inner end of the lever 27 inwardly of the pin 28 is a lifting and lowering pawl 32. The pawl 32 is of channel-like formation with opposite flanges 38. The lower portions of the flanges 38 of the pawl 32 are pivoted to the lever 21 by a pin 33 and its upper free end is pointed as shown at 34 and is adapted to engage the ratchet teeth [9 of the ratchet; lift member I! in the normal operation of raising or lowering the lift member.

One of the features of the present invention embodies a cable which is trained about a pulley on the lift ratchet member and operatively associated with the operating lever for doubling the lifting effect of the lift jack and utilizing the upward stroke of the lift lever as well as the downward stroke of the lever to raise the object being lifted. This novel mechanism includes a flexible element or cable, generally indicated by the reference character 35, which has one end securely connected to a cable bracket 36. The cable bracket 36 has formed on its lower end a curved bearing portion 31 which embraces the pin 33 between the flanged portions 38 of the pawl 32. The cable bracket 36 reciprocates through an opening 39 in the upper portion of the housing l3. An intermediate portion of the cable 35 is trained about a pulley d3 which is journaled on a transverse pin ill supported in aligned apertures in the opposite side walls of the lift member [1, as clearly shown in Fig. 2 of the drawings. Embracing the top end of the lift member I! is a curved pulley and cable shield 42 which has depending a-pertured ears, as shown at 13, through which the pin ii extends for retaining the shield in position. The pin is retained in position by oppositely disposed cotter pins 44. The other end of the cable has secured thereto a cable bracket 35 which, in turn, is provided with an apertured end, as shown at 55, for connecting the same to a hook t? for lifting the object generally indicated by the reference character 58.

The mechanism which controls and synchronizes the operation of the lifting and holding pawls Will next be described. The lifting pawl 32 is normally depressed in the direction against the ratchet teeth iii of the lift member I1 by a spring t9, the coils of which embrace the pin 33 and has one end thereof, as shown at 50, extending into an apertured ear i formed on the inner end of the lever 27. The other end of the spring 49 extends into an opening 52 of the pawl 32.

Pivoted to one side wall l3 of the housing l3 on a pin 53 is a lifting pawl releasing lever or cam 54. The cam lever 54 is normally pressed in a direction toward the operatin handle 21 by a spring 55 which is mounted in a cup-like socket 56 welded to one of the side walls [3' of the housing IS. The upper end of the lever 54 has a beveled edge, as shown at 5?, arranged substantially at an angle of forty-five degrees with respect to the longitudinal length of the lever. This bevel or cam portion under certain operating conditions, is adapted to engage a laterally projecting pin 58 secured to one of the side flanges 38 of the pawl 32. The pin 58 projects through a rectangular opening 59 in one of the side walls i3 of the housing It. Pivotally suspended from the pin 58 between one of the side walls [3 of the housing i3 and the lever 54 is a holding pawl cam lever 60. The cam member 68 has two divergingly beveled surfaces El and 62 on one edge thereof which is adapted to engage a laterally projecting pin 53 under certain operating conditions hereinafter described. The pin 63 extends through the opposite flanges 64 of the pawl 20 and through an opening 65 in one of the side walls ii! of the housing !3. The cam 60 is normally pressed against the pin 63 under certain operating conditions by an inwardly bent lug 66 formed integrally on one edge of the lever 54. Obviously the action of the spring 55 in actuating the lever 54 will actuate the lever 60 to engage the pin 83 and thereby disengage the dog 20 of the ratchet teeth I9 of the lift member ll. The hand operating control lever which controls the jack for either lifting or lowering is generally indicated by the reference character 61. The control lever B! is pivoted to a pin 63 which, in turn, is secured to one of the side walls [3 of the housing I3. The inner end of the lever has a flat or straight end, as shown at 69, which is adapted to engage the forward edge of the lever 54 when in the position shown in Fig. 1 of the drawings for holding the beveled surface 51 of the lever 5-4 out of the path of the pin 58 of the pawl 32 and when the lever 67 is in this position, the jack is in position for the lifting operation. The fiat edge 69 of the lever 61 terminates in curved corners, as shown at l0, so that the lever 31 may be freely actuated downwardly to the position shown in Fig. l of the drawings, in which case the cam surface 57 of the lever 54 is actuated to a position in the path of the pin 58 of the pawl 32 or the position shown in Fig. 4 of the drawings, for the operation of lowering the jack or lift member ll. An arcuately curved shield TI is welded to the inner end of the control lever 67 to engage the outer side of a lever 55 and prevent its displacement with respect to its pivot. An extended portion, as shown at 12, is formed integrally with the shield portion H and bent into U-shaped formation to form a spacer and an additional bearing portion on the pin 68. The shield member and its extended portion i2 are welded to the lever 67. A cover plate, generally indicated by the reference character 13, is adapted to be placed over the operating cam mechanism and secured to the housing N by suitable screws 14.

Summarizing the advantages and functions of operation of my improved jack, it will be observed that the down stroke of the operating lever 21 constitutes a working stroke and the upward stroke of the lever serves as an energy storing stroke in each cycle of operation. In other words, on the down stroke of the operating lever 21, the lift or ratchet member I1 is raised. On the up stroke of the same lever, the cable is actuated around the pulley to exert a temporary or counterbalancing lift of the object being raised. It will be noted that the pulley and cable arrangement of the jack is such that it is capable of lifting the object being raised a distance to twice that to which the lifting rack I! is raised.

In Fig. 1 of the drawings, the control lever 61 is in a raised position so that the cam 69 of this lever actuates the lever 54 so that the beveled end 51 thereof is out of the path of the pin 58 and the spring 49 normally presses the pawl 32 against the ratchet teeth [9 of the lift member I! so that on the down stroke of the hand operating lever 27, the lifting pawl 32 lifts the lift member I 1. In this position, or the position shown in Fig. l of the drawings, the cam member 60 idles and the spring '21 normally presses the pawl 20 against the teeth H! of the lift member IT to hold the lift member in elevated position on each reciprocation of the lever 21. In this connection it will also be observed that on the raising movement of the lever 21, the cable 35 is actuated a slight distance around the pulley to lift the load 48 on the upstroke since the inner end of the cable is connected to the inner end of the lever 21.

When the operator desires to lower the load,

or lower the jack, the control lever 61 is actuated to the position shown in Fig. 4 of the drawings in which position the spring 55 presses the cam lever 54 into position in which the beveled end 51 is in the path of the pin 58 of the pawl 32 and upon the up stroke of the lever 21, the pressure of the spring 55 against the lever 54 will actuate the pin 58 to disengage the pawl 32 when the load is transferred to the holding pawl 20. Then upon the down stroke of the lever 21 in the lowering operation, the cam 62 of the cam member 60 will engage the pin 63 of the holding pawl 20 and by the action of the spring 55 and the lug 66 of the cam lever 54 will disengage the pawl 20 from the ratchet teeth l9 when the pawl 32 releases the load by engaging the next succeeding or higher tooth [9 from the holding pawl 20, thereby successively lowering the object by a step by step movement of the operating lever.

From the above description it will be readily seen that I have provided a very simple, compact and easily operated jack and one in which employs both strokes of the lever to raise or lower an object to be lifted and one which will extend the lifting distance to twice the distance of the normal operating lift member.

While in the above specification I have described one embodiment which my invention may assume in practice, it will, of course, be understood that the same is capable of modification and that modification may be made without departing from the spirit and scope of the invention as expressed in the following claims.

What I claim as my invention and desire to secure by Letters Patent is:

1. A lifting jack comprising a main frame, a lifting member mounted in said main frame, a holding pawl mounted on said frame and adapted to engage said lifting member, a lifting pawl mounted on said frame and engageable with said lifting member, an operating lever pivoted to said frame and operatively related to both of said pawls, a control lever carried by said frame and operatively related to said pawls for synchronizing the operation of said pawls, a pulley journaled on the upper end of said lift member, and a flexible element trained about said pulley and having one end thereof connected to said control lever on one side of the pivot thereof and the other end of said element connected to the object to be lifted.

2. A lifting jack comprising a main frame, a lifting ratchet member mounted in said main frame, a holding pawl pivoted on said frame enber, an operating lever pivoted to said frame, a

lifting pawl pivoted on one end of said operating lever, means carried by said frame and operatively related to said pawls for synchronizing the operation of said pawls, a control lever pivoted on said frame for controlling the operation of said means, a pulley journaled on the upper end of said ratchet member, and a flexible member trained about said pulley and having one end connected to said operating lever adjacent one side of its pivot and the other end thereof connected to the object to be lifted.

3. A lifting jack comprising a main frame, a lifting ratchet member mounted in said main frame, a holding pawl pivoted on said frame enageable with the ratchet teeth of said lift member, an operating lever pivoted on said frame, a lifting pawl pivoted on one end of said operating lever, means carried by said frame and operatively related to said pawls for synchronizing the operation of said pawls, a control lever pivoted on said frame for controlling the operation of said means, a pulley journaled on the upper end of said ratchet member, and a cable trained about said pulley and having one end connected to said operating lever at a point common with the pivot point of said lifting pawl, the other end of said cable being connected to the object being lifted.

4. A lifting jack comprising a main frame, a ratchet lifting member vertically mounted in said frame, a spring pressed holding pawl pivoted to said frame and engageable with said ratchet member, an operating lever pivoted to said frame, a lifting pawl pivoted to said operating lever inwardly of the pivot of said lever, a spring normally pressing said lifting pawl into engagement with said ratchet lift member, a holding pawl cam member pivotally carried by said lifting pawl and operatively related to said holding pawl, a lifting pawl release member pivoted to said frame and operatively related to said lifting pawl, a spring for normally urging said pawl release member in one direction, means for operatively connecting said pawl release member to said holding pawl cam member, a control lever pivoted to said frame and operatively related to said lifting pawl release member for controlling the operation of both pawls, a pulley journaled on the upper end of said lift member, and a flexible element trained about said pulley and having one end thereof connected to said control lever on one side of the pivot thereof -with said ratchet lift member, a holding pawl cam member pivotally carried by said lifting pawl and operatively related to said holding pawl, a lifting pawl release member pivoted to said frame and operatively related to said lifting pawl, a spring for normally urging said pawl release member in one direction, means for operatively connecting said pawl release member to said holding pawl cam member, a control lever pivoted to said frame and operatively related to said lifting pawl release member for controlling the operation of both pawls, and a cable trained about said pulley and having one end connected to said operating lever at a point common with the pivot point of said lifting pawl, the other end of said cable being connected to the object to be lifted.

GUSTAV C. MONCKMEIER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 549,458 McKinney Nov. 5, 1895 1,093,269 Hindman Apr. 14, 1914 1,483,002 Lane Feb. 5, 1924 1,672,260 Hopkins -1 June 5, 1928 1,918,934 Schwerin July 18, 1933 2,474,045 Freeland June 21, 1945 2,530,577 Gurries Nov. 21, 1950

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