USRE18820E - Fluid sealing means - Google Patents

Description

May 2, 1933. J. A OLSON Q FLUID SEALING MEANS Original Filed May 18, 1929 fay/v 4 04505.

will be had to the accompanying Reissued May 2, 1933 PATENT OFFICE oin: A. 'oLson, or omvanann, omo

rum) SEALING mums Original No. 1,754,704, dated April 15, 1930, Serial No. 364,035, filed Kay 18, 1929. Application :01- "um filed March 29, 1932.-

My invention relates to fluid pressure devices and more particularly to a piston for use in hydraulically operated mechanisms. An ob]ect of myinvention is to provide unimproved piston, having an annular portion, capable ofconforming to a confining cylinder to prevent escape of fluid past the piston.

Another object of my invention is to con- 0 struct a piston which will,adjust itself to so limited sense.

The aforementioned objects. and other objects of the invention itself will become apparent from the following description of an embodiment. In the description reference drawing forming a part of the In the drawing:

Figure 1 is a vertical, medial, sectional view of a shock absorber embodying the specification.

principles of my invention, a fragmentof an automotive vehicle frame, a bumper and spring being shown attached thereto;

Figure 2 is a longitudinal medial sectional view of another embodiment of my invention;

fied orm of pac in ring.

As b'est shown in igure-l my invention is illustrated as applied 'to' a motor vehicle shock absorber which may conveniently comprise an integral-housing provided with a 4 horizontal cylinder 2 in the lower portion Serial No. 601,834.

and a reserve supply reservoir 3 disposed above the cylinder with a strengthening web 1 disposed in the angle between the cylinder and reservoir. The device is supported by the spring' l, the eye-leaf f the spring be- '0 mg oscillatably pinned to a pair of ears 6 dependin from the, housing, which are provided wit axially aligned apertures therefor. The vehicle frame 7 is supported by a plston or plunger rod 8, the end of which is disposed in a suitable hanger 9 which is secured to the frame.

The piston or plunger rod 8 carries at its free end a piston assembly which is adapted to be disposed in fluid-tight engagement with w the walls of the cylinder 2, the cylinder being disposed in thelower portion of the housing in a horizontalposition. The cylinder is threaded at 11 and the endis adapted to be closed by a suitable plug 12 screwed there- 66 The cylinder is provided with an annular recess 13 adjacent the front end to provide a fiuid'passage which is adapted to communicate with atransverse canal 14 within the allowing fluid to .pass into the cylinder around the edges thereof but restricting the fluid when it tends to flow in the opposite direction. Fluid may pass from the reservoir? through the port 20 disposed at the lower end of the reservoir into the passages 88 13, canal 14 and bore 15 past the valve 19 which as described acts as a check valve.

The piston rod 8 is provided with a tapered end 21 adapted to be seated in a tapered recess in the lower end of the hanger 9 and is secured to the hanger by a nut 23 screwed uponv the threaded end of the rod.

The cylinder is provided "with an enlarged counterbore adjacent the end and the other end of the rod extends through the counterbore into the cylinder. A suitable packing nut 24 is screwed upon an externally threaded end 25 of the cylinder. A flanged thrust bushing 26 is disposed within-the packing nut with the flanged end of the bushin engaged by the inner end wall of the pac ing nut. The bushingis adapted to be pressed into engagement with a plurality of packing washers 27 and 28. Each washer 27 comprises an annular portion 29 and longitudi nally disposed relatively short tapered lip 30 adjacent the central aperture and which is adapted to surround the rod to contact therewith. Interposed between each of the like washers 27 are plain flat washers 28 having a relatively large bore which are adapted to space the members 27. Pressure of the bushing upon the washers 27 causes the lip ofeach washer to telescope through the enlarged bore of the plain washers to enga the rounded inner portion opposite the 11p edge in 'such a manner that the lip is pressed into firm contact with the surface of the piston rod 8 holding the same in fluid-tight engagement with the rod. The lip on the last washer is engaged by the edge of the annular recess 31. The lips of the washers being trained in the direction toward the free end of the rod serve with a scraping action, to

prevent the escape of fluid therefrom.

A piston which comprises a stem 32 and piston body 33 is secured to the end of the rod 8 with the stem 32 dis osed in the axial boreof the rod. The b0 y is of generally cup-shape with the side wall tapered toward b the forward edge, as best shown in Figure 1.

An inwardly extending annular flange 35 isprovided spaced from the bottom of the cu which is undercut at 36 to form an annu ar groove. The walls of the cup adjacent the edge of the groove are relativel thin and a plurality of V-shaped notches 3 are provided in the wall which extend longitudinally along the inner side of the wall of the piston and are adapted to connect with the groove 36 in such a manner as .to weaken the wall sothat a plurality of minute cracks 33' are formed in the periphery of the piston to render the wall of the piston highly resilient.

An annular packing 39 which may be made of irregularly deformable material such as asbestos material or. the like, of irregular cross sectional shape is provided and is adapted, to be seated within the slanting walls of the piston abutting the flange 35. An expander head 38 holds the packing within the cup against the flange 35 and is provided with a slanting, wall 40 adapted .to contact wlth-the packing substantially as shown. The stem 32 of the piston which is disposed in the bore of the rod is provided 7 body of the piston in such a manner as will cause the converging walls of the ex ander to force the packing into the piston orcingthe resilient wall of the piston into fluid-tight engagement with the cylinder.

The construction of the reservoir 3 is such as to provide an air chamber 45 above the fluid and to also permit gradual equalization of pressure between the air in said chamber and the atmosphere. 1

' Air may enter through a hollow plug 46 which is screwed into a suitable threaded aperture 47 in the top of the reservoir. The plug is provided with an axial bore from end to endon three different diameters, the uppermost and largest bore 48 provides a receptacle to receive a dust-straining material,

such'as fibrous material 49, which in turn are held in place b a perforated plate 50, which may in turn be snapped into position in an annular groove 51 adjacent in the top of the plug. A. relatively smaller bore 52 is provided below the larger bore and connected thereto and connects with a restricted passage .53 in the end of the plug of such size as to permit slow passage of airtherethrough and which is not large enough to interfere with the cushioning effect caused the compression of air above the level of the fluid in the cylinder 3, but permits suflicient air to seep into the chamber to prevent the formation of a vacuum should some-of the necessity of measurement of fluid placed therein.

. The web 2' may be apertured as at 55 and the reservoir formed to permit'a socket 56 in order that a bumper ma be attached to the reservoir by U-bolts 5 which extend around the reservoir through the web. With a rubber cushion 58 .interposed between the bumper 59' and the reservoir.-

As best shown in the Figure 2, I provide an alternate 'type'of piston which is shown disposed in.-a cylinder 60 which might be the sleeve or cylinder of a hydraulic jack or v the like., The piston comprises a stem 61 is provided with an annular 1 body substantiallyas shown. The wall 65 of the ring is provided with a plurality of V-shaped grooves such as, 37, Fig. 4 as described for the other embodiment which permits minute cracks 33 to form in the periphery thereof. The stem 63 serves as a guide for the cap or compression member 67 Conventional washers of flexible type such as leather washers are disposed about the stem 63 to seal the space between the cap 67 and the stem 63 against passage of fluid.

, beof asbestos and force the walls of the The packing member 7 O is disposed in the groove and the recess in such a manner that it is substantially dove-tailed into the groove. A suitable compression member 67 is adapted to be disposed about the stem 63 and telescoped into the space surrounded by the annular portion of the ring 64 and annular flange 67 .extends over the packing adjacent to the wall of the cylinder. The member is held in position upon the stem 63 by a suitable nut 68 disposed in a central recess 69 of the compression member.

The compression member is adapted to move relative to the piston in such a man-- ner as to compress the packing which may 1ston into fluid-tight engagement with the cylinder wall.

As best shown in Figure 5 I show another type of packing which I sometimes contemplate using in the place of those heretofore described shown and which comprises a core of asbestos or similar material surrounded by a metallic envelope of copper, lead composition or the like.

Having thus described my invention, I am aware that numerous and extensive departures may be made therefrom but withoutdeparting I claim: 1. A fluid pressure device comprising a cylinder and a piston movable therein, said from the spirit of my invention.

piston having an expansible annular flange extending from one end thereof, said annular flange being weakened circumferentially near itsbase and also axially and having an inclined inner surface, a cap movable relatively towardand away from the piston, and pac ing means to prevent the ingress of fluid under pressure into the space between the ca and the piston, said packing means inclu ing a flexible packing'member interposed between the flange and the cap,

and engaging the said inclined inner surface, to expand the flange into fluid sealing relatively toward and away from the piston,

a cap guiding member and packing means to prevent the ingress of fluid under pressure into the space between the cap and the piston, said packing means including a flexible packing member interposed between the flange and the cap and engaging the said inclined inner surface to expand the flange into. fluid sealing contact with the cylinder walls when fluid pressure is exerted against the cap to move the latter toward the piston, and a second flexible packing member interposed between and closely engaging the cap and the cap guiding member to prevent ingress of fluid under pressure into the space between the cap and the piston. 3. A fluid pressure device comprising-a cylinder and a piston movable therein, said piston including a body member and a second member, the said members bein movable relative to each other and providing a space therebetween, one of the members having an expansible vannular flange extending toward the other member, the flan e bein weakened circumferentially near its %ase an also axially and having an inclined inner surface, and packing means to prevent the ingress of fluid under pressure into the s ace between the said members, said pac ing means including a flexible packing member interposed between the flange of one member and the other member and enga 'ng the said inclinedinner surface of the ange to expand the flange into fluid sealing contact with the cylinder wall when fluid pressure is exerted against one of the members to move the said member relative to the other member.

4. In combination, two relatively movable members having contiguous surfaces, fluid sealingmeans on one of said relatively movable memberscomprising an annulus axially weakened to provide segments adapted to bear against the contiguous bearing surface of the other of said movable members, said segments having relatively thin end portions and inclined surfaces whereby the segments are progressively thickened, said segments being weakened adjacent the bases of said thickenedportions, deformable acking material arranged to press ra ially against the inclined surfaces of said se ments to cause said segmentsto engage sald contiguous bearing surface, and means for compressing said material.

5. In a fluid pressure device, two relatively movable members, fluid sealing means on one of said relative] movable members comprising an expansi 1e annular flange, said- 5 flange being weakened circumferentially near its base and also axially and having an inclined surface, flexible packin means adapted to engage said inclined sur ace, and

means for pressing said packing means against said inclined surface including a member movably mounted with respect to said flange and subjected to fluid pressure.

In testimony whereof I hereunto aflix my signature-this 21st day of March, 1932.

y JOHN A. OLSON.

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