US3890684A - Method of making a hydraulic jack - Google Patents

Abstract

A weight lifting hydraulic jack has a supporting base consisting of a single block with the pump cylinder cast integrally with the base. A vertical assembly consists of a central vertical hydraulic cylinder in which a lifting ram reciprocates and the hydraulic cylinder is concentrically mounted within a cylindrical housing and these two parts are cast as a single unit. Free ends of the cylinder and housing are given cast shapes precisely fitting cast receptacles in the base. Self threading bolts extend through cast holes in the base into cast holes in the vertical assembly holding the entire jack together. After a conventional ram is fastened in the hydraulic cylinder and a conventional pump piston and actuating linkage is pinned in place on the base by a single screw, the jack is ready for operation.

Description

[451 June 24, 1975 2,863,285 12/1958 Pomeroy.....................,. 254/93 H X Primary Examiner0thell M. Simpson [57] ABSTRACT A weight lifting hydraulic jack has a supporting base consisting of a single block with the pump cylinder cast integrally with the base. A vertical assembly consists of a central vertical hydraulic cylinder in which a lifting ram reciprocates and the hydraulic cylinder is concentrically mounted within a cylindrical housing and these two parts are cast as a single unit. Free ends of the cylinder and housing are given cast shapes precisely fitting cast receptacles in the base, Self threading bolts extend through cast holes in the base into cast holes in the vertical assembly holding the entire nny .l CS6 mpa epb m n cmu to P n .l na S 3 6 mm m fi .m l r amp F m m g md W W w a am r. R S D 0np l 9 n ar 5 e k un me a H h l A v C L gw 8 mm m C a S fu o ak ty g k e ah taa XHHHHH H33333 @3359 %44444 /55555 22222 2 an JACK Inventor: Erven Tallman, 15934 S. Figueroa St., Gardena, Calif. 90247 Filed: May 9, 1974 Appl. No.2 468,532

US. 29/156.4 R; Int. Cl...... 323p 15/00; F15b 15/18; B66f 3/24 Field of Search........ 254/93 R 29/156.4 R, 156.4 WL

References Cited UNITED STATES PATENTS United States Patent Tallman METHOD OF MAKING A HYDRAULIC Johansson et M .m Wm m m VJ m wm n ne Cmru n S 1 e oo eh RGHKP 9940 8 334555 999999 HHHHHH 470044 577003 46926 ,B 35 7000 566252 2229.27.

SHEET 1 METHOD OF MAKING A HYDRAULIC JACK Axel jacks as that term is commonly used are vertically operating jacks which comprise a hydraulic cylinder mounted on a base, the cylinder being short enough to permit the jack to be slid between a supporting surface and the axel of an automotive vehicle. The squatty character needed for a jack of this kind has prompted the construction wherein the cylinder for a conventional hydraulic ram is located concentrically within an annular reservoir for hydraulic fluid formed by employment of an outer cylinder A pump casing of cylindrical form is located on the base adjacent the first defined cylinders and a conventional pump mechanism is attached to the base with a pump piston extending into the pump chamber, and a fitting permitting insertion of a relatively long pump handle long enough to reach under the chassis of the vehicle while permitting the jack to be comfortably operated.

Construction of such devices has followed purely conventional practice for a great many years, such practice encompassing individual cylindrical members provided with threads on the exterior permitting them to be.-fastened into threaded recesses formed in the base. Conventional construction further calls for the concentric cylinders forming respectively the hydraulic ram chamber and the annular reservoir to be pulled downwardly into sealing engagement with the base by a threaded nut at the outer end. Usually a collar, threaded at least for reception of the inner cylinder is employed at the outer ends of the cylinders to close the reservoir and at the same time assist in providing means for drawing the outer cylinder into sealed engagement with the base. Although this structure has satisfied the need for compactness, threaded connections always tend to be weak spots where high hydraulic pressures are encountered, especially where the device is subject to rough treatment at times causing the threaded connections to become damaged. A further and highly obj'ectionable characteristic of such devices is the need for a relatively large number of individual parts each of which must be individually and separately manufactured, inventoried, and then laboriously assembled in a dependable fashion. The result of this is that not only are jacks of such construction subject to deterioration during use but the operations involved are so numerous that with the prevailing high cost of labor the resulting product is unnecessarily costly.

In an effort to minimize prospective leaking situatioris in a jack construction of this kind and also to make it possible to use lighter weight materials resort has been had to welding whereby to replace threaded joints. Although welding does have the advantage of providing what becomes ultimately an integrated structure this practice still requires that a relatively large number of pieces be provided initially and that these pieces in turn be welded together one weld at a time to produce what ultimately may aptly be described as a fused structure. Welding practices are often costly even when modern machinery is used and there is always the ever present possibility that a welded joint may be defective and the' piece have to be scrapped after inspection.

It is therefore among the objections of the invention to provide a new and improved weight lifting hydraulic actuated jack which is of such construction that relatively few parts are needed and hence the operation of assembling the parts appreciably reduced whereby to cut the production cost, without sacrificing dependabil- 1ty.

Another object of the invention is to provide a new and improved weight lifting jack wherein virtually only two units are prepared by a casting technique such as die casting or impact aluminum casting with virtually all surfaces ultimately to be relied upon for contact with operating parts formed by the initial casting operation thereby to very greatly minimize the labor involved in assembling the device as well as the labor which might be involved in maintenance and servicing.

Still another object of the invention is to provide a new and improved weight lifting jack of such die cast construction that it can be formed of material such as aluminum of relatively lesser strength than steel, the structure and technique being such that sections of aluminum material can be maintained almost as thin as corresponding sections of steel of much greater strength, the structure however being one wherein mutually reinforcing ribs are cast at stratigic locations so that different portions of the device such as concentrically located spaced cylinders reinforce each other in the finished design thereby providing adequate strength at a reduction in cross-sectional area and weight.

Still another object of the invention is to provide a new and improved weight lifting jack wherein virtually all porting is cored or machined from within, leaving no cores or holes exposed thereby to guard to a maximum degree against inadvertent leakage.

Still further among the objects of the invention is to provide a new and improved weight lifting hydraulic jack wherein by providing cast holes and recesses at strategic locations the relatively few separate parts can be mounted together in operating condition by use of just a few self-tapping screws thereby to greatly minimize the cost of production and in consequence provide a device the low cost of which can be passed on to the consumer.

It is an object further of the invention to provide a construction such that the general arrangement of the weight lifting jack can remain undistrubed under circumstances where just one or two internal dimensions need to be varied, when the parts are cast, to provide for a jack having either lower or higher lifting ratings while keeping the other parts of the structure virtually the same thereby to minimize inventory and appreciably reduce the cost for jacks of various different capacities.

With these and other objects in view, the invention consists of the construction, arrangement, and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

FIG. 1 is a front elevational perspective view of the completely assembled axel jack.

FIG. 2 is a vertical sectional view on the line 22 of FIG. 1.

FIG. 3 is a fragmentary vertical sectional view showing the location of the parts in uppermost extended position.

FIG. 4 is a cross-sectional view on the line 4-4 of FIG. 2.

FIG. 5 is a fragmentary vertical sectional view on the line 5-5 of FIG. 1.

FIG. 6 is an exploded view of the principal parts of the invention.

FIG. 7 is a fragmentary exploded view showing assembly of the two principal parts of the invention.

FIG. 8 is a fragmentary vertical sectional view showing the parts of FIG. 7 after assembly.

FIG. 9 is a fragmentary transverse sectional view on the line 99 of FIG. 1.

In an embodiment of the invention chosen for the purpose of illustration a weight lifting hydraulic jack designed as an axel jack in assembled and operatable condition is shown in FIGS. 1 and 2 indicated generally by the reference character 10. In operating condition the axel jack consists of a base 11 on which is mounted a vertical assembly 12. A lifting ram 13 is housed in the vertical assembly 12 for manipulation upwardly and downwardly when activated by a pump assembly indi cated generally by the reference character 14.

As shown in FIG. 6 the base 11 consists of a single piece which can be made for example as either a die cast aluminum block or an aluminum impact molded piece. It is of material significance that, except for a limited number of transversely drilled bores, the entire base consisting of a block 15 on which is an integral pump housing 16, is completely formed in one operation. That is to say, all of the recesses, holes, slots, and bores are formed to their final shape and dimension by the casting or molding operation.

The parts just described include an inner central recess l7 and an outer stepped recess 18 which is concentric with the inner central recess. Also formed initially is the cylindrical bore 19 in the pump housing, the vertical oil passage 20 and the oil feed passage 21 which communicates with it. Slots 22 and 23, which relate to pump action, are initially formed when the block 15 is cast.

For cooperation with the pump assembly there is provided a release valve screw 25 and when the block 15 is cast an opening 26 is formed by suitable coreing technique which results in there being provided also in axial alignment with the opening 26, an inner opening 27 of reduced size which communicates with an axially aligned high pressure connecting passage 28, the high pressure connecting passage 28 being initially formed in communication with the vertical oil passage 20 through a passage 29 as shown in FIG. 6.

The junction of the inner opening 27 with the high pressure connecting passage 28 forms a valve seat 30 on which seats a valve element 31 of the release valve 25. To simplify the assembly of the release valve 25 there are provided on the release valve self-tapping threads 32 which cut their way into the inner opening 27 suitably dimensioned to receive the self-tapping threads on initial assembly. Flats 33 provide for a wrench hold and a seal ring 34 on the release valve has a sealing fit within the opening 26.

Also on the initial forming of the block 15 holes 35, 36, 37, and 38 are cored for ultimate use in final assembly. Further still when the block 15 is initially cast there is provided a pump mounting bore 39 in axial alignment with passages 40, 41, and 42 for the accommodation of a pump mounting bolt 43 provided wth a selftapping thread 44 which threads its way into the passage 42 suitably sized to receive it during the initial forming operation.

The vertical assembly 12 is also formed as a single piece by comparable die casting or pressure molding.

As shown to good advantage in FIGS. 2 and 3 the vertical assembly consists of an exterior cylindrical case 50 and a concentrically disposed inner cylinder 51 spaced from the cylindrical case to form an annular reservoir 52 for hydraulic fluid. In order to have the inner cylinder 51 strong enough to withstand the necessary hydraulic pressure and at the same time be constructed of material such as aluminum by the technique herein suggested, ribs 53 are formed by the same casting technique, three ribs 53 being shown in FIG. 4 by way of example, extending from the inner cylinder 5] to the exterior cylindrical case 50. The inner cylinder 50 provides a cylindrical chamber 54 for accommodation of the lifting ram 13.

Further as shown in FIG. 2 upper ends respectively of the exterior cylindrical case 50 and the inner cylinder 51 are joined integrally by an annular section 55. The lower end of the exterior cylindrical case terminates in an annular flange 56 precisely sized to fit within the outer stepped recess 18 of the block 15. Similarly the adjacent end of the inner cylinder terminates in an annular flange 57 which is sized to precisely fit within the inner central recess 17, and to do this the inner cylinder 51 is made slightly longer than the exterior cylindrical case. An annular footing 58 extends around the exterior of cylindrical case 50 at a location adjacent the annular flange 56, the footing being adapted to seat upon an upper face 59 of the block 15.

When the vertical assembly 12 is initially formed there is molded in the annular flange 56 an annular recess 60 for ultimate reception of an O ring 61. Similarly, there is initially formed in the annular flange 57 an annular recess 62 for ultimate reception of an O ring 63.

During the same initial forming there is provided near the upper end of the inner cylinder 51 an annular recess 64 in communication with the cylindrical chamber 54 by means of a port 65. Adjacent the annular recess 64 is a shoulder 66. An annular snap ring recess 67 is preferably milled into an annular wall 68, as initially formed, after the vertical assembly has been completely molded.

When assembling the vertical assembly 12 with the base 1 l exemplified by the block 15 the 0 rings 61 and 63 are slipped into the respective recesses and then the vertical assembly is pushed into the block to the position where the annular flange 56 is fitted into the outer stepped recesses 18 and the annular flange 57 is fitted into the inner central recess 17 where 0 rings provide a seal and where the annular footing is pressed against the upper face 59. In this position socket head bolts 69, four in number as shown in FIG. 6, each provided with a self tapping thread 70, are extended through the respective holes 35, 36, 37, and 38 through which they pass freely. When the vertical assembly 12 is initially formed there are provided a series of pockets 71 in respective alignment with the holes 35, 36, 37, and 38, the pockets being of a size adapted to threadedly receive the self-tapping threads as the socket head bolts are driven into place. By virtue of this arrangement the entire vertical assembly is completely mounted on and assembled with respect to the base 11 by placing the two parts together in the manner described and driving home four socket head bolts 69.

For completing the operating needs of the vertical assembly the lifting ram 13 is inserted into the cylindrical chamber 54, accompanied by seal rings 72 and 73 which confine between them an O ring 74. A snap ring 75 is then projected into the snap ring recess 67 to confine the lifting ram 13 to the cylindrical chamber 54.

For rendering the pump assembly operative a pump piston 80 is projected into the cylindrical bore 19 in the pump housing 16. At the same time linkage arms 81 and 82 are inserted in the respective slots 22 and 23 where they are pivotally secured by insertion of the pump mounting bolt 43 as heretofore described. A bracket 83 providing a pump handle socket 84 is pivotally attached to the linkage arms by a pivot pin 85 and also pivotally attached to the upper end of the piston 80 by means of a pivot pin 86. Mounted as described the pump is ready for operation.

To provide the necessary communication between the pump and release valve passages and the reservoir 52 and cylindrical chamber 54 there are provided return passages 87 and 88 and a pressure passage 89. The return passage 87 communicates between the reservoir 52 and the oil feed passage 21 in which is located a check valve 90, the check valve permitting flow into the cylindrical bore 19 of the pump. The return passage 88 communicates between the reservoir 52 and the high pressure connecting passage 28 but only when the release valve 25 is open.

The pressure passage 89 communicates through the high pressure connecting passage 28 with the passage 29 and thence to the cylindrical bore of the pump, there being a check valve 91 in the last identified passage.

It is significant that all of the passages 87, 88 and 89 extend from the interior of the block namely the recesses 17 and 18, outwardly to the communicating passages. They may be formed by drilling from the interior outwardly to the connecting passages after the block 15 has been cast or. by proper coreing, can be formed initially in communicating condition. What is of special significance is that they are not drilled from the exterior of the block so that there is no possible prospect of faulty construction due to leakage. To further simplify the connection between the pressure passage 89 and the cylindrical chamber 54 a mouse hole or notch 92 may be initially formed by the casting operation when the inner cylinder 51 and exterior cylindrical case 50 are formed, thereby to eliminate a drilling or ma ehining step.

To avoid damage to the axel jack by over pressuring when the lifting ram has been extended to its highest position there is provided a relief valve mechanism at the lower end of the lifting ram 15. A transverse relief passage 95 is in communication with the annular recesses 64 heretofore described and an axial relief passage 96 extends from the transverse relief passage 95 downwardly through an opening 97 to the cylindrical chamber 54, as shown in detail in FIG. 3, and in phantom lines in FIG. 2. A spring actuated ball check 98 is normally seated by spring action against a valve seat 99 thereby closing the relief passages 96 and 95 when the lifting ram is being pushed upwardly by hydraulic pressure. A transverse trip rod 100 which has a sloppy fit in the transverse relief passage 95, has a leg 101 which extends downwardly through the passage 96 to a position of potential engagement with the spring ball check 98. When the lifting ram reaches the top of its stroke as shown in H6. 3, the trip rod 100 is pushed against the seal ring 72 and as the lifting ram 13 continues to be driven upwardly, the leg 100 unseats the spring ball check 98 so that hydraulic fluid under pressure is by passed through the relief passages 96 and 95 respectively to the annular recess 64 and port into the reservoir 54. Any continued pumping after this relief mechanism has become operative will continue to bypass the hydraulic fluid.

Normally it can be assumed that the lifting ram 13 has been lowered to its lowest position within the cylindrical chamber 54. When the ram is to be operated the release valve 25 is rotated so that the valve element 31 seats upon the valve seat 30 and closes off communication between the high pressure connecting passage 28 and the return passage 88. When this condition prevails and the pump piston 80 is operated hydraulic fluid from the reservoir 54 will be drawn through the return passage 87 past the check valve 90, into the lower portion of the cylindrical bore 19 of the pump, during up stroke of the piston 80. When the piston is moved downwardly hydraulic fluid from the cylindrical bore 19 is driven outwardly through the passage 29 past the ball check 91 to the high pressure connecting passage 28, and then through the pressure passage 89 and mouse hole 92 into the cylindrical chamber 54. Pressure in the chamber 54 is exerted against the bottom of the lifting ram 13 and forces it upwardly. As the piston 80 is reciprocated, upwardly for the next stroke, the ball check 91 seats, preventing return flow from the cylindrical chamber 54 while hydraulic fluid again flows from the reservoir 54 through the return passage 87 into the cylindrical bore of the pump.

After the lifting ram has been lifted to the desired position and it then is to be returned to disengage it from the work, the relief valve 25 is rotated to unseat the valve element 31 from the valve seat 30 thereby to permit hydraulic fluid from the chamber 54 to flow back through the pressure passage 89 to the high pressure connecting passage 28 and from there to be bypassed through the return passage 88 to the cylindrical chamber 54 which comprises the reservoir.

The lifting ram 13 to the extent that it is provided with seal rings 72 and 73 with the O ring 74 between them and a second lower 0 ring 105, confined between rings 106 and 107, and a sleeve 108, is substantially conventional construction and readily available. The pump assembly also to the extent that it consists of the pump piston 80, linkage arms 81 and 82 and the bracket 83 is also a substantially conventional mechanism. A shoulder 109 however, may be provided on the linkage arms 81 and 82 to definately determine the stroke of the pump during each reciprocation.

As has been previously pointed out, assembly of the base 11 with the vertical assembly 12 can be accomplished extremely rapidly and inexpensively while at the same time in a manner which makes certain that all of the parts are secured in operative relationship. The socket head bolts 69 are entirely concealed beneath the lower face of the base. The only additional operation is to initially thread the release valve 25 into its opening 26, the threads being cast with the initial assembly. Since the base is completely cast as to all of its parts in one operation as is also the vertical assembly, the cost of manufacture as well as the cost of assembly is reduced to virtually a minimum. These parts moreover, are so fashioned in their initial forming that the only additional operations consist of dropping the lifting ram 13 into position wherein it is locked by operation of the snap ring and placing the piston in the cylindrical bore 19 and then fastening the linkage arms 81 and 82 in their pivoted position by merely driving into place the single self-tapping pump mounting bolt 43, again by virtue of the fact that the base 11 and vertical assembly 12 is so constructed by the single initial operation that these assembly expedients with conventionally acquired accessories can be simply and quickly performed. The cost of assembly of a completely operating weight lifting jack can be reduced to virtually a minimum.

Having described this invention, what is claimed as new in support of Letters Patent is as follows:

1. A method for forming and assembling a weight lifting jack for reception of a conventional hydraulic ram and a conventional pump piston and pump actuating mechanism therefor,

and for attachment of a pump release valve screw,

said method comprising forming a base unit by casting therein concentric radially spaced recesses having annular walls and circumferentially spaced fastening holes extending from the bottom upwardly,

casting a pump housing on the base unit with a downwardly open pump cylinder bore therein,

forming a relief valve bore in a communicating relationship with the exterior and said pump cylinder bore,

and forming hydraulic passages between said recesses and said pump cylinder bore,

forming a vertical unit by casting concentric radially spaced inner and outer cylinders whereby to provide a ram chamber in the inner cylinder and a reservoir between the inner and outer cylinders closed by material of the casting at the outer end,

cast forming inner ends of the cylinders to fit into the respective inner and outer recesses, casting circumferentially spaced anchoring recesses in respective alignment with said anchoring holes,

and finally fastening said units together with self tapping bolts extending between said holes and said recesses.

2. A method as in claim 1 including cast forming a release valve bore in the base unit from an exterior location to a location in engagement with said pump cylinder bore, forming a release valve element with self tapping threads adjacent the inner end and injecting said release valve element into said release valve bore.

3. A method as in claim 1 including making said casting of an aluminum material, making the wall of the inner cylinder relatively thin in proportion to the performance requirement of the jack, and casting reinforcing ribs in the reservoir between the inner and outer cylinders whereby to strengthen the inner cylinder in proportion to said performance requirement.

4. A method as in claim 1 including forming annular recesses at respective areas of engagement of said cylinders with said recesses and inserting resilient O ring seals in said recesses.

5. A method as in claim 1 including forming a shoulder in said cylindrical chamber at the outer end, forming a snap ring recess in said cylindrical chamber at the outer end further out than said shoulder, placing an O ring seal means on said shoulder and locking said seal means and the ram in position by insertion of a snap ring in said snap ring recess.

6. A method as in claim 1 including forming the pump cylinder bore by the initial casting operation to extend from inside said base through the outer end of said pump housing, and forming an O ring recess in the wall of said pump cylinder bore adjacent the outer end of said pump housing for reception of an O ring to seal said pump piston.

7. A method as in claim 1 including casting slot means having spaced parallel walls in the base for reception of the pump actuating mechanism and fastening the pump actuating mechanism to said base by use of a single self tapping bolt extending into a recess in the base and through the walls of saidslot means.

8. A method as in claim 1 including forming all said hydraulic passages from a location within said concentric recess in a direction radially outwardly into engagement with others of said passages.

Claims (8)

1. A method for forming and assembling a weight lifting jack for reception of a conventional hydraulic ram and a conventional pump piston and pump actuating mechanism therefor, and for attachment of a pump release valve screw, said method comprising forming a base unit by casting therein concentric radially spaced recesses having annular walls and circumferentially spaced fastening holes extending from the bottom upwardly, casting a pump housing on the base unit with a downwardly open pump cylinder bore therein, forming a relief valve bore in a communicating relationship with the exterior and said pump cylinder bore, and forming hydraulic passages between said recesses and said pump cylinder bore, forming a vertical unit by casting concentric radially spaced inner and outer cylinders whereby to provide a ram chamber in the inner cylinder and a reservoir between the inner and outer cylinders closed by material of the casting at the outer end, cast forming inner ends of the cylinders to fit into the respective inner and outer recesses, casting circumferentially spaced anchoring recesses in respective alignment with said anchoring holes, and finally fastening said units together with self tapping bolts extending between said holes and said recesses.

2. A method as in claim 1 including cast forming a release valve bore in the base unit from an exterior location to a location in engagement with said pump cylinder bore, forming a release valve element with self tapping threads adjacent the inner end and injecting said release valve element into said release valve bore.

3. A method as in claim 1 including making said casting of an aluminum material, making the wall of the inner cylinder relatively thin in proportion to the performance requirement of the jack, and casting reinforcing ribs in the reservoir between the inner and outer cylinders whereby to strengthen the inner cylinder in proportion to said performance requirement.

4. A method as in claim 1 including forming annular recesses at respective areas of engagement of said cylinders with said recesses and inserting resilient O ring seals in said recesses.

5. A method as in claim 1 including forming a shoulder in said cylindrical chamber at the outer end, forming a snap ring recess in said cylindrical chamber at the outer end further out than said shoulder, placing an O ring seal means on said shoulder and locking said seal means and the ram in position by insertion of a snap ring in said snap ring recess.

6. A method as in claim 1 including forming the pump cylinder bore by the initial casting operation to extend from inside said base through the outer end of said pump housing, and forming an O ring recess in the wall of said pump cylinder bore adjacent the outer end of said pump housing for reception of an O ring to seal said pump piston.

7. A method as in claim 1 including casting slot means having spaced parallel walls in the base for reception of the pump actuating mechanism and fastening the pump actuating mechanism to said base by use of a single self tapping bolt extending into a recess in the base and through the walls of said slot means.

8. A method as in claim 1 including forming all said hydraulic passages from a location within said concentric recess in a direction radially outwardly into engagement with others of said passages.

Images