US1834547A - Hydraulic lifting jack - Google Patents

Description

Dec. 1, 1931. L. D. NlLsoN 1,834,547

HYDRAULIC LIFTING JACK Filed Dec. 3l, 1928 2 Sheets-Sheet l Jill/laici' ,Z zand/d 17, 72H10@ Dec. 1, 1931. L. D. NlLsoN HYDRAULIC LIFTING JACK Filed Deo, 3l, 1928 2 Sheets-Sheet 2 Jaz/miaf *Liana/fa 2 ,Wi/Jam fiar/vg.:

Patented Dec. 1, 1931 UNITED STATES PATENT OFFICE LEONARD D. NILSON, OF WAYZATA, MINNESOTA, ASSIGNOB TO MARQUETTE MANUFAC- TURING COMPANY, 0F ST. PAUL, MINNESOTA y HYDRAULIC LIFTING J' ACK .Application led December 31, 1928. Serial No. 329,326.

10 means consisting of a check valve and a release valve, one of which may be opened by the operating handle being positioned at a predetermined point and the other thereof, controlled by an independent controlling Still a further object is to provide a construction in which the independent controlling means is operable only upon the operating lever assuming the predetermined posi- 20 tion for opening the check valve.

Still a further object is to provide a flexible connecting means for the controlling mechanism for the purpose of opening the re-` verse valve and which assumes a substantially taut position only upon the operating handle assuming the position for opening the check valve,

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings. Although the invention is susceptible of a variety of embodiments, it is unnecessary to fully ldescribe and illustrate more than one in order to give a full understanding of the invention both from its structural and functional standpoints. Accordingly, I have v illustrated a preferred and desirable embodiment of the invention in the accompanying drawings in which: i

Figure 1 is a plan view of my jack structure, part of the operating handle being cut olf. f

i Figure 2 is aplan view of the part of the operating handle not shown in Figure 1.

Figure 3 is a side elevation of my structure showing the lifting head in raised position by means of dotted llnes.

Figure 4 is a side elevation of the outer end of the operating handle.

Figure 5 is a detail sectional view on the i line 5-5 of Figure 1.

Flgure 6 1s an enlarged sectional view onA the line 6-6 of Figure 1.

Figure 7 is a sectional view on the' line 7-7 of Figure 1, illustrating the operating handle in raised position.

Figure 8 is an enlarged sectional view of a portion of Figure 7 showing the parts in a different position; and

Figure 9 is a detail sectional view on the line 9--9 of Figure 8.

On the accompanying drawings I have used the reference numeral 10 to indicate the front axle of my jack. Wheels 12 are rotatably mounted on the axle 10. Rear Wheels 14 are provided for the jack structure and are of the swivel or caster type. Each wheel 14 is swivelly mounted in hubs 16 .formed on brackets 18.

The frame of my jack consists of side bars 20 and castings 22. The front axle 10 is secured to the frame members 22 and the brackets 18 are secured to the side bars 20. The members 20 and 22 are bolted together as clearly illustrated on the drawings. At the rear end of the jack frame, a cross member 24 serves to space the side bars 20.

The frame members 22 extend rearwardly and upwardly and terminate in portions adapted to support a pivot bolt 26. Pivoted on the bolt 26 is a lifting arm 28 having a lifting head 30 pivotally mounted on the outer end thereof. The connection between the lifting head 30 and the lifting arm 28 is shown at 32 in Figure 1 of the.drawings. In con` nection with the lifting head 30 I provide stabilizing arms 34 pivoted to arms 36 extending from the lifting head 30 and to pivot bolts 38 in the frame members 22.'

For swinging the lifting arm 28 and consequently, raising the lifting head 30 I provide a hydraulic mechanism consisting of a cylinder 40 and a piston 42. The cylinder 40 is provided with -a head 44 having a pivotal connection by means of a pin 46 to the lifting arm 28.

As clearly illustrated in Figure 5, the lifting arm 28 is triangular in shape and the pin 46 is mounted. at one corner of the trian le. The piston 42 is mounted on a piston ro 48 -Which in turn is secured to the hub 50 of a yoke 52. The arms of the yoke 52 are piv.

oted by means of bolts 54 to forwardly extending frame members 56 located at the rear end of the ack.

From the construction of the parts just described, it will be obvious that the cylinder 40 may be moved relative to the piston 42, the piston itself being mounted stationary relative to the frame of the jack and the cylinder in formation and thus provides a pump cylinder for the plunger 60.

As shown in Figure 6, the forward end of the plunger 60 is provided with a fitting 62 4 to which a cup-leather 64 is secured by means of a fitting 66. The cup-leather 64 servesthe purpose of sealing against leakage of oil past the plunger and through the piston rod or pump cylinder 48.

The piston 42 itself is of cup-leather construction and secured to a piston head 68. Within the piston head 68, inlet and outlet check valves and 72 are provided. Thus a tubular piston rod 48, plunger 60 and check valves 70 andv 72 form a pump for pumping oil from the rear side of the piston head 68 to the forward side thereof for the purpose of moving the cylinder `40 relative to the piston 42.

In the piston head 44 a check valve 74 is provided which allows oil to by-pass from the passage 76 through a passageway 78 to the oil reservolr 80 mounted above the cylinder 40. The reservoir 80 is covered by a cover plate 82 having a filler plug 84.

For allowing oil to iiow from the reservoir 80 .top the cylinder 40 on the rear side of the plston head 68, I provide an opening 86 shown in Figure 5 of the drawings. In the event of an over-load being imposed on the lifting head 30, oil from the pump structure will open the valve 74 and thus the valve acts as a safety device. The spring 88 holding the valve 74 in closed position, may be designed to take-care of any desired overload, the stronger the vspring the greater the load may be without opening the valve 74.

For reciprocating the pump plunger 60 and thereby actuating the valve 70 and 72 and forcing oil from the rear side of the piston head 68 to the front side thereof, I provide an operating handle 90. The handle 90 is pivoted at 92 to the rearwardly extending frame members 56. By means of a latch 94 the operating handle is connected wlth an oscillatably mounted member 96. The latch 94 may be operated from the handle Portlon 108 of the handle 90 by means of a lever 110. The latch 94 coacting with notches 98 formed in the member 96, allows for adjustment of the handle 90 relative to the member 96.

The oscillatable member 96 is operatively connected with the pump plunger 60 by means of links 100. The links 100 are connected with the member 96 by a pin 102 and to the pump plunger 60 b means of a collar fitting 104. The pump p unger extends througha packing nut 106 on the outer end of the piston rod 48.

The pump plunger 60 is of hollow construction to receive a reverse valve rod 112. The rod112 extends through a packing nut 114 in the outer end of the tubular pump plunger 60 and is provided with a ange 116. A yoke shaped lever 118 is pivoted between the links 100 ona pin 120. The arms of the yoke member 118 contact with the flange 116 on the valve rod 112. The valve rod 112 is provided with a collar 122 and a spring 124. The spring 124 serves to hold the reverse valve 126 against itsseat in the fitting 62, at

the forward end of the plunger 60.

A flexible connection such as a chain 128 is provided for the yoke member 118. The chain 128 connects with a pull rod 130 terminating in a handle portion 132 adjacent the handle .member 108. The pull rod 130 is provided with a portion 134 adapted to extend through aslot 136 formed in one of the side bars of the operating handle as shown in Figure 2.

Practical operation In the operation of my jack, the member 96 may be oscillated for imparting lifting movement to the lifting head 30 by pumping the handle 108 upwardly and downwardly. This causes the pump plunger 60 to draw oil through the inlet valve 70 and discharge it through the outlet valve 72 into the cylinder 40. This extends the hydraulic connection consisting of the cylinder 40`and the piston 42 so that the lifting head 30 may be moved to the dotted lines position shown in Figure 3.

For lowering the jack it is necessary to move the operating handle 90 to its ,lowermost position whereupon the pump plunger 60 will assume the position shown in Figure 6 of the drawings. In such position, a stem 67 on the fitting 66 will open the valve 72 for allowing oil to iiow from the cylinder 40 in front of the piston head 68 and into the piston head itself.

It is now necessary to open the valve 126 so that oil may iow from within the piston head 68 through the openings 61 and 49 formed in the pump plunger 60 and piston rod 48 respectively. The spring 124 is holding the valve 126 closed and to open the valve, the pull rod 132 must be moved to the dotted line position shown in Figure 2.

It will be noted that the chain 128 is slack whenever the handle is up as shown in Figure 7 but is nearly taut when the handle is in` lowered position as shown in Figures 3, 5 and 8. Thus it will be seen that the reverse valve 126 may be opened only when the operating handle 90 is in its lowered position where it may open the valve 72. Thus the operating handle may be utilized for ordinary raising operations and for part of the lowering operations but if it should be accidently moved to lowered position, the jack will not .be lowered because the pull rod 132 must be operated in conjunction with the lever 90 for lowering the lifting head.

Some changes may be madein the con-l struction and arrangement of the parts of my device without depart-ing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use o mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. A jack structure comprising -a low wheeled horizontally arranged elon ated frame, a lifting head mounted on said rame at one end thereof, an actuating mechanism on the other end of said frame, means of connection between said mechanism and lift- Ving head including a hydraulic pump structure having a piston, a cylinder'mounted on stituting a reservoir for the fluid actuating said structure, said cylinder having operative connection With the lifting head and movable therewith and relative to said piston and means located within the piston for allowing oil to be transferred from one side thereof to the other but normally preventing its return, a portion of said last means being operable independent of over-operation of the means within the piston for the purpose of allowing oil to flow in an opposite direction for lowering the lifting head, and means within the head of said cylinder serving to by-pass oil from one side of the piston to the other side thereof when the jack is overloaded.

2. A jack structure comprising a low wheeled horizontally arranged elongated frame, a lifting head mounted on said frame at one end thereof, an actuating mechanism on the other end of said frame, means of connection between said mechanism and lifting head including a hydraulic pump structure having a piston, a cylinder mounted on and receiving said pistonsaid cylinder constituting a reservoir for the fluid actuating said structure, said cylinder having operative connection with the lifting head and movable therewith and ,relative to said piston and means located within the cylinder head and responsive to the load imposed thereupon for Vsaid frame and its other end pivoted to said lifting arm for swinging the same when the hydraulic mechanism is actuated, said mechamsln com rising a piston rod and a cylinder slidable re ative thereto and a pump structure in said piston rod, said pump structure including check valves, a reciprocable plunger, and means actuated by over reciprocation thereof to open one of said check valves for allowing oil to flow therethrough, means within said plunger to allow said oil to ass by the other check valve and a rod wit in the plunger and reciprocable to operate said last mentioned means.

4. In a jack structure, a frame, a lifting arm pivoted thereon and a hydraulic actuat- 1n said frame and its other end pivoted to said lifting arm for swinging the same when the hydraulic mechanism is actuated, said mechanism comprising a piston rod and a cylinder slidable relative thereto and a pumpstructure in said piston rod, said pump structure including check valves, a reciprocable plunger, and means actuated by over reciprocation thereof to open one. ofsaid check valves for allowing oil to flow therethrough, means within said plunger to allow said oil to pass by the other check' valve and a rod within the plunger, controlled externally thereof and reciprocable mentioned means.

5. In a jack structure, a frame, a lifting arm pivoted thereon and a hydraulic actuating mechanism having one end pivoted to said frame and its other end pivoted to said lifting arm for swinging the same when the to operate said last Vhydraulic mechanism is actuated, said mechamsm comprising a piston rod and a cylinder slidable relative thereto and a pump structure in said piston rod, said pump structure including check valves, a reciprocable plunger, an oscillatable handle for reciprocating said plunger, and means actuated by over reciprocation thereof to open one of said cheek valves for allowing oil to flow therethrough, means within said plunger to allow said oil to pass by the other check valve and a rod within the plunger and reciprocable to operate said last mentioned means, said handle being provided with control means thereon to reciprocate said rod.

6. In a jack structure, a frame, a lifting arm pivoted thereon and a hydraulic actuating mechanism having one end pivoted to mechanism having one end pivoted to A lll said frame and its other end pivoted to said lifting arm for swinging the same when the hydraulic mechanism is actuated, said mechanism comprising a piston rod and a 5 cylinder slidable relative thereto and a pump structure in said piston rod, said pump structure including check valves, a reciprocable plunger, an oscillatable handle for reciprocating said plunger, and means actuated by l0 over reciprocation thereof to open one of said check Valves for allowing oil to flow therethrough, means Within said plunger to al- W said oil to pass bv the other check valve and a rod within the plunger and reciprocable to operate said last mentioned means, said handle being provided With control means thereon to reciprocate said rod, said control means being operable only when the handle is in a predetermined position. LEONARD D. NILSON.

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