US2618122A

US2618122A - Telescopic hydraulic jack

Info

Publication number: US2618122A
Application number: US770346A
Authority: US
Inventors: Gratzmuller Jean Louis
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-04-18
Filing date: 1947-08-25
Publication date: 1952-11-18
Anticipated expiration: 1969-11-18

Description

N0V 18 1952 J. L. GRArzMuLLER 2*,618-,1'2'2 l 'rELEscoPIc HYDRAULIC .mex

Filed Aug. 25, 1947 4 sheds-sheet' 1 u lr/ 9.2

NGV 18, 1952 J. L. GRATZMULLER 2,618,122

TELEscoPxc HYDRAULIC JACK Filed Aug. 25, 1947 4 Sheets-Sheet 2 Je@ n LOUA s GFQ-mulle Nuvi 'TOR Nov. 18, 1952 J. L. GRATzMuLLER 2,618,122

TELEscoPIc HYDRAULIC JACK y Filedv Aug. 25, 1947 4 Shasta-sheet s Jaarw LQU'IS Grqf' Thuile( 4 INVENTCME EM AT1-V5 Nov. 18, 1952 J. L. GRATzMuLLr-:n 2,618,122

TELESCOPIC HYDRAULIC JACK Filed Aug. 25, 1947 4 sheets-sheet 4 @MM/@ am Patented Nov. 18, 1952 TELESCQBIQ HYDRAULIC- JACK Jean Louis Gratzmuller, Paris, France Application Augusty 25, 1947, Serial No. 770,346 In France April 18, 1946 section. i, Public, Law 69o, August s, 1941s` 'Patent expires April 18;,'1966 i Claims.

Many proposals have hitherto been made with a View to procuring reliable sealing, guiding and stroke limiting means forl telescoping parts of hydraulic lifting jacks.

- However, the telescopic parts for such jacks, hitherto proposed, are generally too complicated and necessitate a particularly'accurate machining of the various requisite members thereof.

- It is an objectv ofthe present invention to provide in a hydraulic lifting jack' reliable sealing, guiding and stroke limiting means for the telescopiiigparts. which will be simple in yconstruction and in mounting, and which will do away with the--necessity-of laccurate machining, while p ossessing the requisite qualities. l

The sealing, guiding and stroke limiting means designed according to the present invention include substantially an annular sealing and guiding gasket set suitably interposed between the end portions of each two parts intended to be telescoped into each other, guiding members cooperatingwith said gasket set for guiding the desired telescopic movements of said parts, and abutment members adapted to support said gasket set and .tolimit the said telescopic movements.

In the present form, said gasket set is const'tuted by a metalliccollar whose entire lowermost portion is bottomed with an expansble member supported by one of the said abutment means, said collar and expansible member being jammed in between the walls of corresponding telescoping parts, in a recess managed aty the end ofl one of saidl parts.

Said guidi-'ng means are constituted bythe me'-l talli'c portion of said gasket set and by longitudinallysuperimposed suitable' annular members' suitably fixed between the walls of respective telescoping parts, some of these members being u-sed at the same time as dirt catchers.

Said abutment means may be constituted either by suitable annular shoulders managed on" the Walls of respective telescoping parts, or preferably by packstrings of the class including piano strings housed in suitable annular grooves managed in the wallsv of respective telescoping parts.

The sealing, guiding and stroke limiting means as hereinabove outlined according to the invention arev particularly applicable to hydraulic or pneumatic llifting jacks, more particularly to jacks of the telescopic type.

tis. therefore, a further object of thev present invention to providev a lifting jack ofv this kind in which particularly advantageous use is made of the above-outlined sealing, guiding and stroke limiting means.

Other objects of the present invention will 'be apparent from the following detailed description and the accompanying drawings inwhich;

Fig. 1 is an axial sectional View showing a sealing and guiding gasket according to thefin'vention,

mounted on a piston displaceable in a cylinder;

Fig. 2 is an axial sectional View showing a hydraulic telescopic lifting jack provided with seal'- ng and guiding gasket according to the inven'- ion; Y

Fig. 3 is an axial sectional view showing stroke: limiting and abutment means according to the invention;

Fig. 4 is an axial sectional viewv showing a modi-- ed form of hydraulic telescoping lifting jack provided with sealing, guiding and stroke limiting means according to the invention;-

Fig. 5 is a detail showing of a hydraulic-mechanism for actuating a lifting jack according to the invention;

Fig. 6 is a detail showing of the mechanism of Fig. 5;

Figs 7 and 8 are vertical and horizontal sectional views, respectively, of further details ofthe mechanism of Fig. 5 ;y and Figs. 9 and l0 are vertical andr horizontal sectional views, respectively, showingyet furth'rdetails of the mechanism of Fig. 5; o

Referring first to Fig. l, designated by 4 is acylinder in which may slide a piston 3'. The lower= most end of this piston is recessed as at I9. Mounted in this recess is a metallic collar t bot= tomed with an annular member 2 made ofplastio or other suitable material, the ensemble of I and 2 forming a sealing joint. It is readily understood that the metallic collar I serves to guide the piston 3 in cylinder 4, while the plastic member; insures the tightness between the parts 3 and'j'fl'.

Although the members I and 2 may be mountedY in the recess i9 withoutl being made fast thereto,r it is preferable to provide an annular abut-.- ment member 20 to prevent the members I V,s iiicl 2 from coming off the piston.

Referring to Fig. 2 showing a hydraulic `telescoping jack, designated by I5 is 'the base f this jack, Id is its housing, I?`-I its pump, while, by la is designated a. controlling devicefor actuat ing said pump. Designated by I3 is afrst cylinder of the jack, in which may slide a second cylinder I'I acting as piston with respect to the cylinder I3.. ADesignated by 6 is a second piston slidable in the cylinder II. By 5 is designated the usual screw which is intended to contact, for exanjiple,l a vehicle, axle priorI to lifting the jack. u V

The lowermost ends of the twopistons 6 and II are recessed as at I9a and I 9b, respectively. On each of these recesses is slid a gasket according to the invention, constituted by a metallic collar I and an annular member 2 made of plastic or elastic material. Designated by I and IIla are abutment members adapted to maintain the gaskets in place. The pistons 6 and II are guided by the annular members 'I and I, while annular elastic members 8 serve as dirt catchers.

It is clear that with the gasket according to the invention the two pistons may move down to the bottom of respective cylinders, in fact down to the bottom of cylinder I3, so that the volume of the jack may be reduced to its minimum. An abutment 28 serves to push the cylinder II into cylinder I3.

Referring to Fig. 3, by 3 is designated a piston located in its cylinder 4. Formed in the piston and cylinder are grooves 33; a piano wire 34 is located in the cylinder Vgroove 33 and a piano wire 35 is located in the piston groove 33. It is clear that when the piston 3 while moving upwards reaches the position shown in Fig. 3, its wire 35 abuts against the wire 34 of cylinder 4.

Referring to Fig. 4, there is shown a hydraulic telescoping jackV embodying all the features of the invention. Designated by I5 is the base of this jack, I4 is its outer casing, while I6-II-I8 is its pump. Screwed into the base I5 is a rst cylinder I3 adapted to receive a second cylinder II acting as a piston with respect to the cylinder I3, while said second cylinder II is adapted to receive a second piston 6 carrying the usual lifting screw 5. The tightness between the said pistons and the cylinders is insured by gaskets '-25 The upward displacement of the piston is limited by an arrangement similar to that illustrated in Fig. 3, said arrangement comprising grooves formed in the cylinder and the piston and adapted to receive piano wires 34 Yand 35,respectively. 'Ihe telescopic movements of pistons 6 and I I in their respective cylinders II and I3 are guided on one hand -by the upper members 1 and I and on the other hand .by the lower members 'I and I. Plastic or elastic rings 8 serve as dust and dirt catchers. An abutment 28 serves to push the cylinder II into cylinder I3. Y

The member I is on one hand suitably fastened to the cylinder I3 and on the other hand maintained in place .by a piano wire 38 engaged into a groove formed at the uppermost end of the cylinder I I. Similarly, the gaskets I-2 are maintained in place by piano wires 2I engaged each in a groove formed in the corresponding piston. Although these dierent members may be maintained in place in any other way, it is preferred to employ, as abutments, piano wire engaged into annular grooves, even when there is only `one groove receiving only one piano wire.

It is to be noted that all cylindrical parts employed are made without any protrusions from their walls, wherefore the fabrication thereof is greatly facilitated.

VIn Figs. 5 to 10 are illustrated, by way of example, a mechanism and some parts of it for actuating the hydraulic telescoping jack shown in Fig. 4. In Fig. 5, I4 is the casing of the jack, while the movable portion thereof is designated by II, comprising two pistons. Designated by I8 is the pump adapted to communicate, on the one hand, through a passage 50 with the oil reservoir in the said casing and, on the other hand, through a passage 5I with the cylinder I3 for thejack, said cylinder being adapted to communicate through the passage 5I, a release conduit 5 I a and a passage 48 in a drainer 49, with the said reservoir. The drainer 49 comprises a valve operating a rod or piston 45 which is urged upwardly by suitable springs and has a head extending through and beyond the upper wall portion of said reservoir. The passage 5Ia is normally closed by a ball 41 applied against its seat by a suitable spring. For setting in communication the passages 5I, 5Ia and 48, and consequently the interior of the cylinders and the casing, it will be sucient to press said piston head downwardly in order that the narrow piston end 48 may remove the ball 41 from its seat. When the draining is completed, the pressure on Athe piston head is released and said communication is then automatically interrupted under the action of the spring.

In order that the desired thrust may be exerted against the piston head 45, the upper portion of the casing I4 is formed with a housing whose upper edge is curved so as to form a shoulder 52. The lever 44, which is intended to actuate the pump I8, is normally engaged into the yoke 53 pivoted as at 54 on the casing I4. For effecting the draining it is suicient to pull the lever from the left to the right in order that it mayy pass from its position 44a, in which it has been en-` gaged into the yoke 53, to its position 44 indicated by full lines in Fig. 5. At this instant it suffices to press the lever end, held in the hand, down,- wardly in order that it may be brought, while pivoting about the point 55, from the position 44 to the position 44D in which this lever presses against the piston head 45.

In order that the end of lever 44 may be maintained in the housing, so that the jack may-be withdrawn from under the vehicle after draining, there is provided in the said end a hole 51 (Fig. 6) into which may .be engaged a pin 56 made fast to the shoulder 52. Instead of such pin-and-hole arrangement, there maybe provided on the casing I4 two protrusions 59, 60 (Figs. '7 and 8) between which may be engaged a pin 6I carried by the lever, or else there may be pro-l 65 into which may be engaged an unreduced pore tion thereof.

It should be understood that the inventionis` not limited to the specific details shown, in par-g ticular to the shape of the metallic part of gasket or to that of its expansible part or to the manner in which these parts are interconnected, nor is it limited to the particular mechanism described and shown for actuating the lifting jack Vcon--V templated, as changes could be effected therein without substantially departing from the spirit of the invention which is intended to be defined .by the claims herein.

y I claim:

1. Ina hydraulic lifting jack of the telescopicv type, the combination with a pump, a reservoir for pressure Huid, a fixed cylinder closed at its lower end, passages forming communication between said reservoir and said xed cylinder by way of the pump. a release conduit for direct flow of duid between said reservoir and said fixed cylinder, and manually operable means for controlling the ow through'said release conduitl of an inner end portion of reduced o uter diameter,

functioning to abut against the bottom of said fixed cylinder, an annular member positioned on said inner end portion of the ram cylinder to guide the same in said Xed cylinder and carrying a packing member having a U-shape in crosssection one leg of which forms a seal with the wall of said xed cylinder and the other leg of which form-s a seal with said inner end portion of the ram cylinder, a second annular member positioned on the inner end portion of said ram to guide the latter in said ram cylinder and carrying a packing member having a U-shape in cross-section one leg of which forms a seal with the wall of said ram cylinder and the other a seal with the inner end portion of said ram, means mounted on the circumferential periphery of said inner end portions to hold said annular members and said packing members in position, and means to limit the upward movement of said ram cylinder and of said ram.

2. A hydraulic lifting jack according to claim 1, wherein the means to hold said annular members and said packing members in position on said inner end portions are constituted by removable spring members inserted in annular grooves provided in the circumferential periphery of said inner end portions.

3. A hydraulic lifting jack according to claim l, wherein the means to limit the upward movement of said ram and said ram cylinder are constituted by removable Aco--operating spring members inserted in annular grooves provided, respectively, in the inner wall of said xed cylinder, in the inner and outer walls of Said ram cylinder and in the outer wall of said ram.

4. A hydraulic lifting jack according to claim 1, wherein the manually operable means for controlling the sow through said messe conduit includes a spring loaded check valve mounted in said release conduit to prevent ilow from the fixed cylinder to the reservoir, a valve operating rod extending outwardly from the jack body arranged to open said check valve against the action of said spring, a removable lever for actuating either said pump or said valve operating rod, pivot means associated with said pump to actuate the same through said lever, and means on said jack body forming a fulcrum point for said lever near said valve operating rod, said fulcrum point permitting to actuate said valve operating rod through said lever independently of said pump actuating pivot means.

JEAN LOUIS GRATZMULLER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS (Addition to No. 601,282)