US1994783A - Hydraulic jack - Google Patents

Description

R E s U A F P. M

HYDRAULIC JACK Orig inal Filed Nov. 25, 1931 2 Sheets-Sheet l March 19, 1935. E, M PFAUSER 1,994,783

I HYDRAUL'I C JACK 2 Sheets Sheet 2 Original 'Filed Nov. 25, 1931 Patented Mar. 19, 1935 UNITED STATES HYDRAULIC JACK Edward M. Pfauser, Milwaukee, Wis, assignor v to Blackhawk Manufacturing 00., Milwaukee,

Wis.

PATENT OFFICE,

Application November as, 1931, Serial No. 511,203

Renewed August 2, 1934 .6C'laims.

This invention relates to hydraulic l cks in general, and more particularly to what are termed portable or dolly jacks.

tive to the pump operating mechanism, whereby the handle can be operated in one of several angular positions to allow for restricted operating space and maintain the most efllcient operation of the pump mechanism. 15

Incidental to the lifting mechanism, a mo e specific object resides in the provision of a jack comprising a stand having a lifting arm pivotally connected thereto adjacent one end and actuated by a'hydrauiic-ram and pump mechanism housed in a unitary casing, pivotally mounted adjacent the same end of the stand, and in close proximity to the actuating handle, thus providing maximum compactness, high-lift, and elimination of excessively long connecting members and links common to present conventional types of jacks.

A further object resides in the novel manner of control of the pump, togetherwith adjustment of the operating handle through the handle itself, thus materially facilitating operation of the 30 jack. I

With the above and other objects inview, which will appear as the description proceeds, the invention resides in the novel construction, combination and arrangement of parts, substantially as hereinafter described and more particularlydefined by the appended claims, it being understood that such changes in the precise embodi ment of the herein disclosed invention maybe made as come within the scope of the claims.

In the accompanying drawings is illustrated one complete example of the physical embodiment of the present invention constructed according .to the best mode so far-devised for the practical application of the principles thereof.

Figure 1 is a plan view of one form of jack' constructed in accordancewiththe present invention. I

Figure 2 is a longitudinal section taken on the line 2-2 of Figure 1..-

Flgure 3 is a fragmentary plan '01 a modified form-of the invention, parts-being broken away and in section to more clearly illustrate structural features.

Figure 41s a detail fragmentary section taken" ll onthellneHofm i Figures 5 and 6 are diagrammatic illustrations of the operation of conventional jacks.

While the present invention relates in general to hydraulic jacks of various types, the same has been illustrated in connection with a dolly jack, 5 to which type certain features of the invention are particularly applicable. For instance, in dolly jacks, such as illustrated, the jack is generally positioned beneath the vehicle by manipulation of the handle, and to facilitate such op- -10 eration't-he handle is generally utilized as a lever to raise the forward end of the jack for shifting, thus permitting the lifting element to be aligned with the desired part of the vehicle. In conventional types of jacks it is necessary to force the handle down to its lowermost position in order to effect the foregoing operation, and where the jack is utilized in restricted spaces, considerable difficulty is encountered. Consequently, adjust ability of the present handle with relation to the pump actuating mechanism allows the handle to be used as a suitable lever in upright position necessary to a confined or restricted space. Referring now more particularly to that form of' the invention illustrated in Figures 1 and 2, the numeral 1 designates generally a frame or stand, comprising a pair of side frames 2 connected-at their forward ends by a transverse axle 3, having mounted thereon the supporting wheels or rollers 4. Carried at the rear ends of the side frames 2 is a pair of opposed stub shafts 5, hav- 'ing mounted on their outer ends rear supporting rollers 6, while secured'to-their inner ends is a. yoke '7, to which is secured in any suitable man- 7 ner a tubular operating handle 8. As-best shown in Figure 1, a transverse shaft 9' connects the side frames adjacent their rear end and has pivotally mounted thereon a lifting arm 9 provided at its outer end with a pivotal shoe 10 for engagement with the load to be raised. The shoe 40 10 is provided with a depending tail piece 11, connected with the side frames 2 by the links 12, pivotally secured to the inner faces of the side. frames by the studs 13.

Thea'ctuating mechanism for operation of the ,45

high. lift of the shoe 10 upon comparatively limited movement of the ram 14. Obviously, as the ram is actuated to raise or lower the arm 9, piv- Otal action of the casing 16 will compensate for the arcuate movement of the arm 9 to which the ram is connected, as heretofore explained.

To effect operation of the pump plunger 15 to create hydraulic pressure upon the ram in the conventional manner, the casing 16 is provided with a bearing 19 having joumaled therein a rocking shaft 20. Secured on the shaft 20, adjacent the plunger 15, is a pair of spaced arms 21 which straddle the plunger 15 and carry a stud 22 which is engaged in the bifurcated end of the plunger 15, as best shown in Figure 2. On one end of the rocking shaft 20 an arm 23 is secured, which arm is connected with an offset arm 24, carried by the yoke 7, by means of a link 25. Thus, as the handle 8 is oscillated, oscillatory movement is transmitted through the link 25 to the rocker shaft 20, causing the plunger to be vertically reciprocated.

Obviously, as the casing 16 rotates on the studs 17, during the operation of the arm 9, the slight relative movement occurring between the casing and yoke is largely compensated for through the link connection 25, thus having no appreciable effect upon operation of the pump mechanism.

Control of the hydraulic pressure, which actuates the arm, is obtained by a conventional release valve 26 threaded into the casing 16 adjacent its rear end. When the valve is open the lifting arm is returned to its lowermost position by means of either the load carried on the shoe 10, or, when the load has been removed, by the spring 27 connecting one of the links 12 with the adjacent side frame 2.

To facilitate actuating of the release valve 26, the same is connected with the rod 28 by the universal coupling 29. The rod 28 projects through the tubular handle 8 and has secured to 1 its upper end a hand grip 30 which is rotatably carried by the handle 8. Thus, in order to effect complete operation of the jack, it is merely necessary to grasp the grip 30 and rotate the same to close the release valve 26, after which the handle 8 is oscillated to actuate the pump mechanism for raising the ram 14, causing the 'arm 9 and lifting shoe to be raised. Then, without performing any other operation than to rotate the grip 30 to open the valve 26, the load is lowered.

As previously set forth in the objects of the invention, and in the specification, it is frequently necessary to operate a jack in restricted space, due to the close proximity of various obstructions. This is particularly dimcult in connection with dolly jacks, and because of the relative size of jacks of this type, it is often impossible to effect normal actuation of the pump mechanism.

Instead, the restricted space permits only a very limited manipulation of the handle over an inefficient arc, resulting in prolonged, tedious operation in order to actuate the jack.

To overcome the foregoing, the present invention provides adjustment between the operating handle and the pump actuating mechanism,

2 which permits the handle'to be adjusted to one of a plurality of operative positions without in any way afiecting the mostefficient actuation of the pump mechanism. To accomplish this the modification illustrated in Figures 3 and 4 utilizes a yoke 7 secured on the stub shafts 5, similar to the yoke 7. However, the yoke '7' is plained, serves to operate the pump. The arcuate face of the detent 31 is provided with a plurality of-recesses 32 for reception of a springurged locking pin 33 carried by the yoke 7. For manipulating the pin 33 to effect adjustment of the yoke '7 with relation to the detent, a reciprocal rod 34 is carried by the yoke and the handle 35, which is secured to the outer end of the tubular member 8. A trigger 36 secured to the rod and projecting through the handle permits actu-' ating of the rod 34, one end of which engages the pin 33 to withdraw the same from the detent when adjustment is' desired. Manipulation of the release valve 26 is obtained in the same manner as described in connection with the other form of the invention. In this instance the knob 30', rotatably mounted on the handle 35, serves to oscillate the rod 28.

From the foregoing explanation, taken in connection with the accompanying drawings, it will .be readily apparent that an extremely simple,

compact and durable jack' structure has been provided, which presents numerous advantages over conventional types of jacks, in that a minimum number of parts are required, which .parts are so assembled with relation to each other as to provide an exceedingly high lift through relatively limited actuation of the operating mechaof conventional jacks as compared with the present jack.

For instance, where the operating handle or yoke 7 is rigidly connected with the arm 24, the arm 24 can only be operated through its most efficient arc, as illustrated in Figure 5, when the handle is oscillated through a corresponding arc. In the position shown, naturally the length of movement transmitted to the connecting link 25, and designated by the letter :0, is the maximum. Assuming then that because of a restricted space within which to'operate the handle it is necessary to raise the same, necessarily the arm 24 must be lowered, as illustrated in Figure 5, thus causing the same to be oscillated through an arc that imparts only limited movement to the link 25, as designated by the letter y, which is materially less than-the distance .r. Obviously, such actuation of the pump mechanism materially prolongs the lifting operation. This is entirely overcome by the adjustable handle disclosed in Figures 3 and 4, which allows the handle to be set at any one of a plurality of operative positions without aflecting the position of the arm 24, thus maintaining the most efficient action of the pump actuating means, and permitting the handle to be used as a lever in one of several positions, for the purcilitate lateralshifting of the same.

til

I claim:-

1. A hydraulic jack comprising a pair of side frames, a transverse shaft connecting the forward ends of said side frames, supporting wheels mounted on said shaft, a normally horizontal lifting arm pivotally mounted between said side frames adjacent their top and rear ends, a casing positioned between said side frames and pivotally connected thereto, the pivotal axis of said casing being below the pivotal axis of said lifting arm and adjacent the rear ends of said side frames, a ram vertically operable in said casing and pivotally connected to said lifting arm. closely adjacent its pivotal axis, a. pump operable in said casing for actuating said ram, alined spaced shafts carried by the side frames at their rear ends, supporting wheels mounted on said shafts, a yoke pivotally mounted on said shafts, means operatively connecting said yoke and pump, and a handle carried by said yoke for oscillating the same.

2. A hydraulic jack comprising a stand, a normally horizontal lifting arm pivotally connected to said stand adjacent its top, a casing pivotally connected to said stand adjacent its bottom portion and below the connection of said lifting arm, a ram vertically operable in said casing and pivotally connected directly to said arm closely adjacent its pivotal connection and in substantially horizontal alinement with the same, a pump positioned forwardly of said ram in said casing for actuating the ram, an oscillatory handle pivotally connected to said stand closely adjacent the rear of said casing, and means operably connecting said handle and pump.

3. In a lifting jack of the class described, a main frame, an operating lever pivoted onthe frame, said lever providing a handle arm and a working arm, a lifting arm pivoted on said frame,

a hydraulicframe pivoted on said main frame,

said hydraulic frame comprising a jack cylinder having a ram guided therein, the ram being pivoted to the lifting arm wherebysaid hydraulic frame swings about its pivot as the lifting arm is raised or lowered, a pump carried by the hy draulic frame, said pump having a cylinder and a plunger, a pump operating lever for actuating the pump plunger, said latter lever having a journal rigid with the hydraulic frame and having a working arm, said working arms in their mean positions being disposed approximately parallel with each other, and a link pivotally connecting said working arms, angular movement of said hydraulic frame about its pivot changing the mean position of one of said arms with respect to the other.

4. In a lifting jack of the class described, a main frame, an operating lever pivoted on the frame, said lever providing a handle arm and a working arm, a lifting arm pivoted on said frame, a hydraulic frame pivoted on said main frame, said hydraulic frame comprising a jack cylinder having a ram guided therein, the ram being pivoted to the lifting arm whereby said hydraulic frame swings about its pivot as the lifting arm is raised or lowered, a pump car-. ried by the hydraulic frame, said pump having a cylinder and a plunger, a pump operating'lever for actuating the pump plunger, said latter lever having a journal rigid with the hydraulic.

frame and having a working arm, said working arms in their mean positions being disposed approximately parallel with each other, and a link pivotally connecting said working arms, angular movement of said hydraulic frame about its pivot changing the mean position of one of said arms with respect to'the other, and means for adjusting the angular position of the handle arm with respect to the working arm of the operating lever to compensate for the changed'angular relation of said one working arm with respect to the other.

5. In a lifting jack of the class described, a main frame, an operating bell crank lever pivoted on said frame and comprising a handle arm and a working arm, the mean position of the working arm being substantially vertical, a lifting arm pivoted on the frame,'a hydraulic frame pivoted on said main frame, said hydraulic frame comprising a jack cylinder having a ram guided therein, the ram being pivotally connected to the lifting arm whereby said hydraulic frame swings about its pivot as the position of the lift ing arm is changed, a pump carried by the hydraulic frame, said pump comprising a cylinder and a plunger therefor, a pump operating bell oted on said frame and comprising a handle arm and a working arm, the mean position of the working arm being substantially vertical, 9, lifting arm pivoted on the frame, a hydraulic frame pivoted on said main frame, said hydraulic frame comprising a jack cylinder having a ram guided therein, the ram being pivotally connected to the lifting arm whereby said hydraulic frame swings about its pivot as the position of the lift-- ing arm is changed, a pump carried by the hydraulic frame, said pump comprising a cylinder anda plunger therefor, a pump operating bell crank lever for actuating the plunger, said lever having a journal rigid with the hydraulic frame, and having a working arm, the mean position of which is substantially vertical, and a link connecting said working arms, and means for adjusting the angular relation between the handle arm and the working arm of the operating lever to compensate for the change in the' mean position of one of said working arms with respect to the other.

EDWARD M. PF'AUSER,

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