US2252826A - Hydraulic jack - Google Patents

Description

Aug. 19,1941. A. ZISKA HYDRAULIC JACK 3 Shasta-Sheet 1 INVENTOR. /4MW Z/J/M BY 22. %/J g ATTORNEY.

Original Filed July ,14, 1939 Aug. 19, 1941. A. ZlSKA 2,252,826

HYDRAULIC JACK Original Filed July 14, 1939 3 Sheets-Sheet 2 INVENTOR. 04m Z/J/m ORNEY.

Aug. 19, 1941. ZISKA HYDRAULIC JACK Original Filed July 14, 1939 3 Sheets-Sheet 3 0 H mm mm mm m E J O m 2 m Q L 4 p 4 f N \N W N MN .wN \N \W \\\\& W n ww NQ R x \w \w: 0 NN m ll b mm [an mm m \Q x m\ x W I \QN "rim--- l g Rm Q N QN \m wb Nu .w%

Patented Aug. 19, 1941 HYDRAULIC JACK Adam Ziska, Wauwatosa, Wis., assignor, by mesne assignments, to American Hydraulics, Inc., Fond du Lac, Wis., a corporation of Wisconsin Original application July '14, 1939, Serial No. 284,437. Divided and this application'July 25, 1940, Serial No. 347,347

6 Claims.

other object to be lifted, and which is so made that a rocking handle is provided that controls the operation of the pump and the release-of pressure from the high pressure cylinder, and which also is used in pushing, pulling or steering the chassis or body portion of the jack.

Further objects are to provide a hydraulic jack of the above character in which a handle is provided which has rotary motion for controlling the relief of pressure from the high pressure lifting cylinder, which has oscillatory motion for operating the pump, and which has sliding motion so that it may be slid forward to rigidly lock the handle to the body or chassis of the jack so that the jack and handle form one elongated rigid unit, the handle being thus temporarily locked against rocking so that the jack may be tilted up on its front wheels if so desired, as for example when it is desired to quickly pull or push the jack to a new location. When the handle is slid forwardly and locked to the jack, the operator merely trundles the jack to the desired .position, the handle being locked in its forward position. When the operator arrives at the new position, he unlocks the handle by a partial rotary motion thereof and thereafter slides the handle backwardly and uses the handle as a pump lever, subsequently rotating a portion of the handle to release the pressure in the lifting cylinder.

In hydraulic jacks there is ordinarily considerable wear at the point where the handle is pivoted to the chassis or body of the jack, and this wear in certain instances is enhanced because of the fact that the pressure applied to the pump is applied off center with reference to the axis of the handle.

This invention is designed to provide a hydraulic jack in which the pump is centrally located thus equalizing pressure on the yoke bearings and minimizing wear, and in which large, easily renewable yoke bearings are pro- I vided.

Further objects are to provide a novel form of hydraulic jack in which a cylindrical rack is provided axially of the pivot line of the yoke and is adapted to be slid transversely by rotation of the handle to thereby operate the relief valve, an elongated pinion being provided on the rotary portion of the handle which meshes with the cylindrical rack and a pinion being provided on the relief valve stem which also meshes with the rack, thereby insuring the correct pitch line relation between the two pinions and the rack, irrespective of the position of thehandle.

In greater detail, objects of this invention are to provide a hydraulic jack in which the handle may be readily detached from the yoke without detaching the yoke from its bearings, thereby permitting a heavy, permanentpivotal connection between the yoke and the body of the jack while allowing ready detachment of the handle.

Further objects are to provide a novel form of handle for a hydraulic jack in which the handle itself is separable into its component parts for shipping and in which it may bereadily reassembled and thereafter may remain in its assembled condition though it is readily attached to and detached from the yoke of the jack when desired.

Further objects are to provide a construction in which the high pressure ports are so formed that they do not have to be plugged after drilling, thereby minimizingleaking, and in which the valves are so made that they are of very simple construction and are readily accessible,

Further objects are to provide ahydraulic jack in which a safety valve is utilized to limit the maximum pressure that may be produced to avoiu straining of the parts, for in hydraulic jacks of this general type :the pressures frequently reach high values, andto so construct the safety valve that it may be adjusted at will to limit the maximum pressure, the safety valve itself being of very simple construction and readily accessible for inspection-or replacement.

Further objects are to provide a hydraulicjack in which a readilyremovable straineris provided between the pump and the res'e oir' so that the oil or other liquid employed may belfreed from any grit or sediment prior. to reaching the pump, the removability of the screen also providing for ready draining of thecapparatuslifQit becomes necessary, and also allowingthe easyinspectiqn of the strainer. ';1 p

Further objects are to provide ahydraulic jack which may be readily-and cheaplyaproduced and which is easy to assemble. ,1

An embodiment of the invention is shown in the accompanying drawingadn-Mhicha Figure 1 isa side "elevationiof theviack with parts broken away and partly in section, such section being taken on the line |-l of Figure 2. n

I line 3-3 of Figure 2.

Figure 4 is a sectional view, partly broken away, on the line 44 of Figure 3.

Figure 5 is a sectional view on the line 5-5 of Figure 4.

Figure 6 is a sectional view on the line 6-5 of Figure 5.

Figure 7 is a sectional detail of the portion of the yoke which receives the handle. 4

Figure 8 is a sectional detail, partly broken away, of a portion of the handle.

Referring to the drawings, it will be seen that the jack comprises the body portion or chassis having the side frame bars I which are joined at their front end by a transverse axle portion 2 which projects outwardly beyond the side frame bars and carries the front wheels 3.

The side frame bars are joined adiacent their rear portion by means of the webbed casting 4 which in turn carries the ram or plunger of the jack and the pump together with the associated valves. The portion 4 of the body portion of the jack consists of an inner shell like member 5 which is internally threaded and anouter shell like member 6. The cylinder I is screw threaded into the shell like member 5 and projects outwardly therefrom and is spaced from the outer shell like member to provide a reservoir 8 for the oil. The front end of the cylinder I is threaded and receives the head 9 which is shouldered and fits into the outer end of the outer shell 6 of the reservoir. If desired, a packing gasket, not shown, may be provided between these parts.

The head 3 is provided with a packing I10 held in place by a gland II, and the piston or plunger I2 of the jack projects through the packing and gland and terminates in a cross-head l3 at its outer end. The inner end of the piston has an enlarged portion I4 which is provided with a leather cup I5 held in place in the usual manner, the casting or body portion 4 being recessed as indicated at IE, to provide clearance for the end nut II which holds the leather cup I5 in place. The cross-head is provided with a pair of upwardly projecting pins I8 to which the retracting springs I3 are attached, the springs being symmetrically arranged as shown in Figure 2.

The lifting bell crank lever of the jack is ind cated at 2|] and is provided with a bifurcated front end that carries the transverse pin 2| which is pivoted to the downwardly extending lugs of the lifting head 22. The rear portion of the lever 20 is pivoted as indicated at 23 to the side frames I. The lever 20 is provided with the pivot pins 24 which are connected by means of a pair of side links 25 with the transverse pin 26 carried by the cross-head I3.

Thus it is apparent from the above description that as the piston l2 moves the cross-head to the right as viewed in Figures 1, 2 and 3, that the links 25 rock the lever 20 into an elevated position and thus raise the lifting head 22. The lifting head is maintained in a horizontal position by means of parallelogram link mechanism. This mechanism may include a pair of side links 21, see Figures 1 and 2, which are pivoted at their forward ends to downwardly extending lugs 28 formed on the head, and at their rear ends as indicated at 23.

The front wheels 3 are relatively small and a pair of relatively larger rear wheels 30 are reshown in Figures 3 and 4.

volubly mounted adjacent the rear portion of the chassis or body of the jack.

The pump is located centrally between the side of the body portion as shown most clearly in Figure 4. Its cylinder is indicated at 3| and its plunger is indicated generally at 32.

The plunger is provided with an enlarged portion 33 and with a leather cup 34. The plunger extends through a guiding gland 35 screwed into the upper end of the cylinder.

The upper end of the plunger 32 carries a removable cup-shaped head 36 which may be locked in place by means of a split washer 31, such washer entering a groove p rtion of the plunger as shown in Figure 3. A spring 33 bears on the under s de of the head 36 and raises the pump during its intake stroke. The pump plunger is stopped at the upper end of its stroke by the engagement of the enlarged portion 33 with the gland 35.

A hole 39 is drilled into the reservoir, see Figure 3, and a tubular strainer 43 is positioned within this hole and spaced from the side walls thereof. This tubular strainer 40 is carried by a threaded plug H which has a recessed or reduced portion 42 provided with apertures as The plug is bored out so as to place the apertures in communication with the interior of the strainer. From Figure 4 it will be seen that the channel afforded bythe reduced portion 42 of the plug communicates with pump passage 43. It is to be noted that a relatively small aperture 44 extends into the pump passage 43 and at its point of junction therewith has a bevelled valve seat, the valve consisting of a steel ball 45. In view of the fact that the pump passage 43-slants downwardly as shown in Figure 4, there is no need of employing a spring to hold the ball in seated position as the ball will seat by gravity, the seating, of course, being enhanced by the oil pressure during the pressure stroke of the plunger. The pump passage 43 communicates with the cylinder 3| of the pump by means of the small aperture 46, see Figure 4.

A relatively larger hole 41 is drilled downwardly to the pump passage 43 and a bevelled seat is formed at their point of union. A valve consisting of a steel ball 48 is provided and seats at this point. A closure plug 43 is threaded into the opening 41 and has a reduced and recessed portion that carries a spring 50 bearing against the ball 48.

A high pressure delivery port or passage 5| leads from the opening 41 from the pump to the pressure cylinder 1, see Figures 4 and 6. This port is formed by drilling inwardly before the cylinder I is positioned and thus it is not necessary to plug this high pressure port 5i. A

relief port 52, see Figure 5, is drilled downwardly I and intersects the high pressure port 5|. It is normally closed by a steel ball or relief valve 53 which cooperates with a seat as shown in Figure 5, and is controlled by a threaded relief valve stem 54 which passes through a suitable packing gland as shown in Figure 5 and termis deof the of leaking apparatus, there isvery little chance A safety valve port 58, see Figure 5, extends upwardly from the pump passage 43. The safety valve port 58 communicates with the discharge port 61 by means of the enlarged portion 68. A valve 6| in the form of a steel ball normally closes the port 68. This valve is urged downwardly by means of a plunger 62 which is urged downwardly by the spring 63. The pressure of the spring is adjusted by means of the screw plug 64 and the screw plug in turn is hidden or protected by means of the upper plug. 65. Thus the maximum pressure may be determined by the adjustment of the pressure of the springs 63 in a very simple and easy manner, thus avoiding excessive or dangerous strains on the apparatus.

A yoke in the form of a hood like member 66 is provided with a transverse hub portion 81 that extends outwardly beyond the hood like portion of the yoke. This hub portion is bored out from end to end to provide an internal passage or opening 61', see Figure 4, and is mounted on relatively heavy trunnion pins 68 whose screw threaded portions 68 are threaded into the side frames I, as shown, most clearly in Figure 4, such pins being preferably provided with nut heads 18. The yoke 66 continues rearwardly to provide a hollow shank 1 I which removably receives the handle. This hollow shank 1| is provided with an internal bayonet slot 12, see Figures 3 and 7, for a purpose hereinafter to appear.

A cylindrical rack 13 is slidably mounted within the hub 61 and meshes at all times with the spur gear 55 of the relief valve so that when the cylindrical rack 13 is slid in one direction, it opens the relief valve and whenslid in the other direction, closes the relief valve, correct meshing being maintained at all times as the axial distance traveled by the threaded stem 54 of the relief valve, see Figure 5, is only a few thousandths of an inch.

The yoke 66 carries a roller 14 which is re volubly mounted on a pin 15. The pin is firmly supported by a pair of lugs both of which are integral with the yoke 66. One of th lugs 16 extends laterally from the side of the yoke 66 and the other lug 11 extends downwardly from the upper wall of the yoke. Thus the roller 14 is adequately supported from the yoke. It is adapted to directly engage the pump plunger 32 and the point of engagement between the roller 14 and the pump plunger 32 is in the central vertical plane of the jack so that uniform hearing pressure on the trunnions 68 is obtained, thus minimizing wear.

It is preferable to provide the yoke 66 with means to limit its downward motion. This is accomplished by providing lugs 18, see Figure 5, which abut corresponding lugs formed on the body portion I.

The handle is shown most clearly in Figures 1, 2, 3 and 8 and comprises two tubular members 18 and 88 which may be detached during shipping but which after being received, are permanently joined by means of the screw 8|, see Figure 8. The handle is providedwith a stud 82, see Figure 3, which may be inserted in the bayonet slot 12 of the shank H of the yoke portion and may be given a part turn to temporarily lock the handle inplace, thereby permitting the ready attaching and detaching of the handle without disturbing the pivot bearings of the yoke structure.

The handle is provided with a control knob or control member 83 which is rigidly carried by a plunger or shank 84 which has a reduced portion to thereby provide an end flange 86 and a shouldered portion 81 between which a limiting screw 88 carried by the sleeve 88 extends, as shown in Figure 8, to thereby allow limited axial sliding motion of the knob or control member 83 of the handle. When the knob 83 is slid inwardly, a pin 88 is adapted to enter a bayonet slot 88 formed in the sleeve 88 and to lock the knob 83 in its forward position. Normally it occupies the position shown in Figure 8.

The knob 83 is connected with an elongated pinion 8|, see Figure 3, by means of an internal shaft. This internal shaft may consist of a squared section 82 which extends into the knob or control portion 83 of the handle and which is. guided adjacent its end by means of a guide member 83, see Figure 8. The extreme end of the squared portion is preferably bevelled as indicated at 84 to provide for its ready insection within a corresponding squared portion of a sleeve 85. The sleeve 85 has a rounded por tion at its outer end which is pinned or otherwise secured to a reduced section 86 of the shaft 81.

The shaft 81 may also be provided with a guiding member 88, see Figure 8, so as to keep it centrally located so that when the handle is assembled after shipping, the squared shaft 82 will be guided into the sleeve 85.

Referring to Figure 3, it will be seen that the shaft 81 extends through a guiding disk, 88 at the forward end of the sleeve 18 and is pinned to the elongated gear 9|. The outer end of the gear or pinion 8I terminates in a reduced extension I88, and when the knob 83, see Figure 8, is thrust forwardly, the extension I88 is adapted to enter an opening I 8| formed in a lug I82 integral with the body portion 4,- to thereby lock the handle to the body portion and allow the body portion to be tilted upwardly about its front wheels. Normally the parts occupy the position shown in Figures 3 and 8.

A spring I83 loosely surrounds the shaft 81 and bears against the end bearing 88 at one end and against a collar I84 pinned to the shaft 81 at its other end, thus urging the shaft 81 rearwardly.

The elongated pinion 8I meshes with the cylindrical rack 13 in all angular positions of the handle and the correct pitch line relation is maintained.

It is obvious that when the knob 83 is rotated, that the gear 8|, see Figure 3, causes the cylindrical rack 13, see Figures 3, 4 and 5, to shift laterally and to thereby rotate the gear 55 and open or close the relief valve.

It is also clear that when the'handle is slid forwardly and the pin 88 locked in the bayonet slot 88, see Figure 8, that the projection I88, see Figure 3, enters the opening I 8I and locks the handle rigidly to the chassis or body portion of the jack, thus allowing the jack to be tilted up on its front wheels and transferred quickly to the 'desired position. Thereafter the knob 83 is unlocked and the handle is thus free to be oscillated up and down to oscillate the pump and to thus elevate the liftinghead of the jack.

No excessive pressures can be produced as the safety valve will open at the desired setting and thus limit the maximum pressures that may be obtained.

Further it will be seen that by having the pump centrally located, bearing pressure on the side trunnions of the yoke portion of the handle is uniform and wear is thus reduced to a minimum. Additionally, the entire handle may be readily detached by giving the entire handle a part turn to detach the stud 82, see Figure 3, from the bayonet slot 12 in the hollow shank H of the yoke, and thus the jack body and its handie may be placed side by side and will occupy very little space.

It will be seen further that the construction is very sturdy, that it has relatively few parts, and that ample bearing areas are provided to withstand the loads imposed thereon.

Further it will be seen that complete control of the jack may be had without having the operator shift his position, as the entire control of the jack is obtained from the outer end of the handle.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. A pump for supplying liquid under pres-' intermediate gear element and maintains operative connection between the outer revoluble end portion of said handle and said relief valve independently of the angular position occupied by said handle, said handle being oscillatable independently of any oscillation of said intermediate gear element.

2. A pump for supplying liquid under pressure comprising a body portion, a handle having a yoke portion pivoted to said body portion for operating said pump, said handle including an outer revoluble end portion, a relief valve for relieving pressure, and means including gearing operatively connecting the outer revoluble end portion of said handle to said relief valve. said gearing including three gear elements one of which is a rack element having cylindrical rack portions for independent engagement with the remaining two elements of said gearing carried ,by said yoke portion, said rack element maintaining operative connection between the outer revoluble end portion of said handle and said relief valve independently of the angular position occupied by said handle.

3. A pump for supplying liquid under pressure comprising a body portion, ahandle havinl a yoke portion pivoted to said body portion for operating said pump, said handle including an outer revoluble end portion, a relief valve for relieving pressure, and means including gearing operatively connecting the outer revoluble end portion of said handle to said relief valve, said gearing including three gear elements one of which is a cylindrical rack element carried by said yoke portion, said rack being cylindrical throughout its extent, said cylindrical rack element maintaining operative connection between the outer revoluble end portion of said handle and said relief valve independently of the angular position occupied by said handle.

4. A pump for supplyin liquid under pressure comprising a body portion, a handle for operating said pump, said handle having a yoke portion pivoted to said body portion and provided with a cylindrical aperture, a cylindrical rack slidably mounted in said aperture and being supported from the walls of said aperture com-' pletely around all portions of said rack, a relief valve for relieving pressure, said relief valve having gearing meshing with said cylindrical rack, said handle having a revoluble outer portion, a shaft operatively coupled to said revoluble outer portion, and a pinion operated from said shaft and meshing with said cylindrical rack and located at one side of said cylindrical rack.

5. A pump for supplying liquid under pressure comprising a body portion, a handle for operating said pump, said handle having a yoke portion pivoted to said body portion and provided with a cylindrical aperture, a cylindrical rack slidably mounted in said aperture, a relief valve for relieving pressure, said relief valve having gearing meshing with said cylindrical rack, said handle having a revoluble outer portion, a shaft operatively coupled to said revoluble outer portion, and a pinion operated from said shaft and meshing with the cylindrical portion of said cylindrical rack.

6. A pump for supplying liquid under pressure comprising a body portion, a handle for operating said pump, said handle having a yoke portion provided with a transverse aperture therethrough, a pair of trunnion members carried by said body portion and projecting into the outer ends of said transverse aperture for pivotally mounting said handle, a cylindrical rack slidably mounted in said transverse aperture between said trunnion members, a relief valve for relieving pressure, a gear operatively con nected to said relief valve and meshing with said cylindrical rack, a second gear carried by said handle and meshing with said cylindrical rack, said handle having an outer revoluble portion, and means operatively connecting said second gear and said outer revoluble portion.

ADAM ZISKA.

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