US1948073A - Hydraulic jack - Google Patents

Description

R. E, MANLEY HYDRAULIC JACK 7 Feb. 20, 1934.

Original Filed Jan. 5. 1926 4 Sheebs-Sheet 1 R. E. 'MANLEY Feb. 20,- 1934" HYDRAULIC JACK Original Filed Jan. 5. 1926 4 Sheets-Sheet 2 lllrlrrlllllmmmdr 1 mg Feb. 20, 1934.

R E. MANLEY HYDRAULIC JACK Original Filed Jan. 5. 192a 4 Sheets-Sheet 3 7 v FILE:

IIII lulllll Patented Feb. 20, 1934 PA-TENT OFFICE I nrnnauuc JACK I Robert E. Manley, York, Pa., assignor to The Manley Manufacturing Company, York, Pa a corporation of Delaware Original application January 5, 1926, Serial No. 79,435, now Patent No. 1,805,588, dated May 19, 1931. Divided and this application May 5, 1931. Serial No. 535,263

11' Claims. (01. 2541-2) This invention relates to automobile jacks, and has for its principal object the provision of a substantially. fool-proof hydraulic Jack having a high lift. I v 1 A further fobject of the present invention lies in the provision of a jack which can accommodate-itself to a very small clearance, is simpie to operate, and yet has suillcient capacity to raise a vehicle or other load to a satisfactory height; Other objects of the invention will be apparent from the following description and claims.

Of all pieces of garage, equipment it is believed the jack is most subject to abuse, and it is therefore essential that an automobile Jack be made as near fool-proof as possible, and particularly as /regards to some means for pre- -venting a thoughtless person from; applying destructive power after the jack has been run to its maximum height,' or when the lifting portion of the jack has encountered a load beyond the possibilities of the jack With the present popularity of the balloon tires it has become quite necessary that a garage jack shall have a very low clearance and it is equally essential that the jack must be capable of taking a very heavy pleasure car to a rather greater height than required with high pressure tires. It is also rather important that the jack should not be too heavy, but yet should be capable of lowering the larger cars with ease and dispatch, preferably without m'anipulating the lever which raises the car.

This application is a division of 'my application Ser. No. 79,435, filed January 5, 1926 which ,became Patent No. 1,805,588, dated May 19, 1931.

In the drawings: Figure 1 is aside elevation.

Figure 2 is a longitudinal cross section. Figure 3 is a plan view. Figure 4 is a transverse section on' line 4-4 Figure 3. Figure 5 is a longitudinal cross section on'line 55 of Figure 3. l

Figure 6 is a plan view partly broken away of the connecting casting.

Figure '7 is a transverse view thru the axis of the saddle. I

Figure 8 is a longitudinal section thru the axis of the pump plunger.

Figure 9 is a trans e section thru the reservoir thru the inlet alve to the pump.

The main frame or chassis of the jack is built up of two upper bars 10 and two lower bars 11 connected to one end at the'front casting 12 and attheother end by'tne rear axle 15, which is secured in each of the rear brackets 16 by a set screw 1'7, the brackets 16 each being permanently fastened to both the upper and the lower bars 10 and 11, respectively, by means of rivets such as. 18. Supported by the side bars 10 and -11 on each side are two large castings 20 and 21, the former being for the tank and pump while the latter, the front casting 21, forms the cylinder in which the hydrau lic piston or ram slides. The pump piston or plunger 22 is connectedby a link 23 with a lever 24 pivoted to the shaft 25, the upper end of the lever forming an upright socket 27 to receive the tongue 28, which is fastened in the socket Jack is moved from place to place by means of the transverse grip bar or handle 33.

The main piston or rain 32 carries a wrist pin 30 fastened by a set screw 31. This wrist pin extends far beyond the piston and projects between the top and bottom side bars 10 and 1].- where it is pivoted-at each side to the walking beams 36 by means of links 38 each of which carries a lug. 39 to which is secured a spring 40 attached at its free end to the frame, and

tending to telescope the piston 32 into its cylinder 2i.

The walking beams 36' are pivoted on the free ends of the upper shaft 40' which is mounted in ing 21. pivoted the, drag links 44 having for their pur- 27 by means of the usual binding bolt 29. The

pose the vertical positioning of the post 45, which carries at its top the usual saddle 46 to engage. a load to be lifted. a

In order to secure rigidity of the walking beam structure it is found convenient to bolt the two beams 36 together by means of a rod 47 and a spacer pipe 48 held in center position between and engaging the beams 36, as by the nuts 49.

trunnions 51 to serve as pivots for the support 50 in the walking beams 36, and also has a pair of shorter trunnions 52 serving as a pivotal conl The post support, or sleeve 50 has a pair of nection for the drag links 44 so that, since the pivots 40' and 53 are directly above one another,

' the pivots 51 and 52 will likewise remain one directly above the other in view of the parallel The upper portion of the tank casting 20" forms an oil reservoir 54 closed at the top by a cover '55 which should be moderately strong-for 86 brackets 42 which may be integral with the cast- I.

To these same brackets 42 at 53 are merely for additional strength and is naturally I optional.

The bottom of the tank casting 20 is formed by an integral member'60 in which there is a cylindrical bore 61, snugly receiving the pump piston or plunger 22,, being in fact the cylin' der-thereof. A ball valve 62 held in place by the spring 63 admits oil thru the ports 64 and 65, during the suction stroke of the plunger, but closes communication between the main tank body or reservoir 54 and the plunger cylinder bore 61 during the powerstroke. As the handle 33 is moved downward and rearward the lever 24 and link 23 move the plunger 22 inward, driving oil thru the passage 66 in the casting 67 and past a check valve 68 to the horizontalpassage 69 and into the chamber 70 of the forward cylinder 21. The piston 32 is provided with a cup washer 72 substantially oil tight, so that as oil is driven into the chamber 70 the ram will move forwardly (i. e., toward the saddle 46) carrying with it the wrist pin 30. and consequently swinging the walking beams 36 about theirpivots 40' so as to raise the saddle or load support 46. r

A foot pedal pivoted at 81 controls'a rod 82 pivotally connected to the foot pedal "80 as I at 83, which rod passes thru a bore 85 in the tank casting 20, and its free end terminates just short of a guide block 87 mounted in the rear wall to the tank casting 20, the block being held in proper position with respect to the check body 67, by the lock nuts 88 and 89. A spring 90 engages the front wall of the tank cast ,ing 20 and also a collar 92 threaded on the,

rod 82 so as to hold this rod yieldingly in contact with a rather short cylindrical needle valve 95, the conical point of which seats in a similarly tapered bore 96 in the guide piece 8'1 while thebody, of the needle valve slides freely in the cylindrical bore 97 at the front end 98 of the guide piece and is constantly in contact with the rod 82 except momentarily when the spring 90 is compressed by the foot pedal 80.

A nipple 100, preferably communicating with the stufllng box groove, connects the rear'end of thepiston chamber ,70 to the tank chamber by means of a pipe 102 connected to the tank chamber by means of an ordinary union 104, andv the nipple 105 threaded into the tank cast-- ing. This arrangement 'is to prevent loss ofoil as I find it advantageous to provide some arrangement for while the three 011 grooves 108 allow but a. very slight leakage, there is always some leakage, with or without rings,.and this leaked oil finds its way backto the tank by way of the pipe 102, there being no restriction to rearward flow in this'pipe (there is no pressure in the tank) and'the pressure behind the ram therefore drives the oil back to the tank since .it is not possible to escape thru the stufling box 109 closing the end of the pump cylinder in the usual manner.

The connecting castingor check body 67 is connected to the guide member 8'7 (which as shown has a bore completely thru it) by'means of a short straight pipe 110 threaded into the casting 67 as at 111, and threaded into the guide piece 87 as at 112, this means furnishing the return passage for the oil from the chamber 70. A) load on the saddle 46 or the pull of the spring 40 or both tend to cause the piston 32 to move forwardly, in case the needle valve is free to move, as when the pedal 80 is pushed rearwardly at the top, in which case the oil passes from the chamber 70 thru the passageway 69, the passageway 114 in the outstanding lug of the casting 67, thru the passage 115 in the pipe 110, into guide 87, and finally into the tank by providing an annular groove 121 in the forward end of the cylindrical chamber 60 and having this groove communicate with the tank 20 by means of a small vertical passage 123.-

There is no tendency for oil to flowinto the groove 121 from the tank chamber as the plung-. er 22 is solid and its rear end never passes the groove. This leakage preventing means, and the quite similar means at the forward end of the ram cylinder areimportant features of the present invention as they insure against the untidiness almost invariably associated with hy-' 'draulic jacks of all types suitable for garage use.

It will be. noted that the check body 67 is threaded into the tank casting 20 as at-130 and is also threaded into the forward or ram cylinder 21 as at 131, hence it is necessary to provide some manner of adjustably mounting the guide block 87 with respect-to the check body 67. The

check body is tapped as at 111 to receive one end of the pipe 110 and the guide block '87 is also tapped at 112 to receive the other endof this short pipe in order to assemble the device, consequently the guide block 87 must be free to move with respectto the tankcasting. I- therefore make the threaded rear portion of the guide member 87 smaller than the hole 133 in the boss 58 of the tank casting which receives it so as to provide a loose fit. When the other parts of the device are properly assembled and in permanent position the two lock nuts are brought to bear against opposite sides of the boss 58 in the tank casting so as to make an absolutely oil tight'joint packing 135 being provided in the usual manner. The small longitudin'al rib 136 is optional but it is very convenient I to strengthen this small block, particularly in view of the vertical discharge orifice 117.

The operation of the device is as follows:--'- The jack as a whole is pulled from place to place by meansof the tongue 28 which is prevented from moving rearwardly, that is, in a direction toward the load support, by a stop member 137 boltedon the link 23 in such position as to engage the pipe spacer 138 so as to insure that 67. With the parts in such position a slight,

further lowering of the handle 33 permits the forward end of the jack to be swung about the front ground wheels 140 as a pivot, raising the much larger ground wheels 141 slightly off the ground. When desiredvthe saddle 46 may be readily yields downward against the spring 63.

so as to allow the oil to pass thru the horizontaltransverse opening 65 leading to the pump cylinder 61. On the downward stroke of the handle 33 and post or tongue 28 the solid piston or plunger 22 moves rearwardly, that is,

toward the load, until a convenient lowest position is reached or in case of a long stroke until the cup washer 150 strikes the tapered threaded rear end of the check body 67.

The oil behind the ram 32 forces the latter toward the rear axle 15 and this movement swings the walking beams 36 about their pivoting shaft 40' by means of the transverse wrist pin 30 at the rear end of the ram and the two parallel links 38 which are pivoted to the walking beams at the lower ends of their short power arms while the load itself is carried at the free end of the longer load carrying arms of the walking beams which load carrying arms are horizontal when they have moved roughly one third of their upward travel. The two walking beams with their rigid cross connections 47- 48-49 form a load carrying frame.

Should the ram or the load support meet an obstacle beyond the strength of the jack no harm is done for the spring 90 is set to open the needle valve 95 at'a pressure giving a satisfactory factor of safety over the possible capacity of the jack. Hence excessive pressure within the chamber simply causes the valve 95 to move away from the seat 96 thus allowing the discharging of oil thru the opening 117 until the pressure is reduced to the selected the highest position desired, that is, .the cubiccapacity of the reservoir shall exactly balance the cubic capacity of the chamber 70 at maximum movement of the ram plus the capacities of the various passageways.

In case it is preferred that the reservoir shall be able to hold an excess or reserve supply of oil some other means for limiting the stroke of the ram must be provided so I have shown a positive stop at 158 which is engaged by the wrist pin 30 .at each side and thereby limits the movement of the ram on its working stroke.

To lower the load, the mechanic presses his foot against the upstanding lever at the front of the truck andthis withdraws the rod 82, compressing the spring 90 and allowing oil to pass from the ram cylinder 70 back to the reservoir 54 exactly as just described in connection with excess pressures. It should be noted that the operator can lower the load either very slightly or very slowly by pressing the foot treadle or lever 80 just suiTlcient to allow a slight escape of oil. The valve 95 is of such length as to remain within its guiding bore 97 when the rod 82 is withdrawn to its greatest extent. The return passages are of such size with respect to the volume of oil used that while the lowering of the load may take place in a very, short period the action is always smooth even tho the pedal 80 is held to maximum release position.

What I claim is: 1. In a jack having a chassis, a pair of spaced parallel levers pivoted about alined axes in said chassis, spaced means for joining said levers to form a frame, a load support on one of said means, and means beneath said alined axes and on said chassis for rocking the frame to raise and lower the load support.

2. In a jack having a chassis, a pair of spaced parallel levers on opposite sides of said chassis pivoted about alined axes in said chassis, spaced means for joining said levers to form-a frame, a. load support adjustably mounted on one of said means, and means beneath said alined axes and on said chassis for rocking the frame to raise and lower the load support. 3. In a jack, a pair of walking beams, a member pivoted to both walking beams, a load support carried by said. member, a ram, and a pair of links connecting said ram and the ends of the walking beams distant from the load support.

4. In a jack, a ram cylinder, a shaft directly above and transverse of said cylinder, a pair of levers pivoted on said shaft, each having a horizontal load carrying arm and a downwardly extending power arm, a ram, and a link connecting each power arm with said ram.

5. In a jack, a wheeled truck, a bell crank lever having a forwardly extending load carrying arm and a power arm, pivoted on said truck on a transverse horizontal axis, a member reciprocatingly mounted in said truck, and a link connecting the forward end of said member with said power arm.

6. Ina jackfa wheeled truck, a ram cylinder carried thereby, a ram in said cylinder, aload carrying arm pivotally mounted on said truck about an axis at a higher level than the center line of the ram, and means-connecting the ram to the said arm.

7. In a jack, a wheeledtruck, a pump and a ram carried in tandem fashion on said truck, a load carrying arm pivoted about a transverse axis so that its loadcarrying end is at one end of the truck in lowered position, a handle for transporting the truck and for operating the pump, linkage connecting the ram and arm, and means secured to the truck adjacent the pump for limiting movement of the'pump in one direction.

' 8. In a hydraulic jack having a ram, a ram cylinder, a pump, and a reservoir so connected that the pump draws fluid from the reservoir and forces it into said ram cylinder behind said ram, a transverse shaft directly above the ram cylinder, a bell crank lever pivoted on said shaft with its, one arm extending downwardly to one side of the ram cylinder, and. alink connecting the ram with said downwardly extending arm.

' 9. In a hydraulic jack having a ram, a ram cylinder, a pump, and a reservoir so connected that the pump draws fluid from the reservoir and forces it into said ram cylinder behind said ram, a lug extending laterally from eachside of the ram, ashaft parallel to said lugs, a pair of load carrying levers pivoted on said shaft and each having a powerarm, and links connecting said arms with said lugs.

'10. In a jack, 2, long narrow wheeled truck, a tank casting and a ram cylinder mounted in tandem fashion thereon, a pair of brackets rising from the ram cylinder, a load carrying arm mounted in each bracket, means connecting the two arms to form a load carrying frame, a saddle carried by said frame, and means connecting said ram and said frame to raise and lower said saddle.

11. In a jack, a long narrow wheeled truck, a

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