US2218638A - Packing - Google Patents

Description

v 25 asbestos fabric or PatentedQct. 22, n

I UNITED? IC T George Christenson;Plainfield; 3' Johns-ManvilleCorporation,

" a corporation'of New York I,

" Qam l eJ y-21,193s, ammo-220,424

" 1 SrClaims. (crysta -2a) M v t .i adequate sealin ehgagement againstthe piston walls until the cupis thoroughly broken in. A

The present inventionrelates to cylinder land piston assemblies, and particularly tosuch assemblies applicable to power'jreverse gear mechanisms, air brakemechanisms, and the like. 1 The invention is. more particularly concerned-with an improved packing to beemployed in cylinderpiston assemblies, constructed and arranged to insure against loss of pressure throughthe materialof thepacking and to provide an eflicient 10 seal between the piston and the cylinder walls.

Cylinder and piston assemblies, of thetypereferred to above, now conventionally, include a packing ring having a base resting upon the piston head and an out-turned lip-or'flangelfor sliding and sealing engagement with wall. Packings of this description .are usually referred to as cup packings" and such terminology will be hereinafter employed. The cup packing isretained inits proper position on the piston head by means of a keeper ring and a1 plurality of bolts or studsextendingthrough the keeper ring and the base of the packing and into further object of the invention'is the provision .of a'li'p constructionfor cupipackin'gs which will overcome thisdisadvantage of" the prior artcups. 5

A further objectof the invention isthe provision of a cuppacking attaining the above d 'flned objects which may be punchd or'drilled to l the cylinder M follow and t to provide apertures for the. penetration of the conventionalsecuring' bolts or the like WithOlltGX- 10 posing the fibres of the fabric of-the packings.

My invention, whereby the above-noted objects are attained, 'will'be fully understood and further objectsand advantages of the invention will become apparentdetailed descriptionof the invention which is to the accompanying drawing, in

which Fig. lis a fragmentary sectional view-of a pisthe piston head. The cup'palcking'sof preferred present practice comprise a suitable laminated the like impregnated with. a compound such as a rubber composition, For I convenience in manufacture, the perforations for the reception of the bolts or studs are formed'by punching or drilling. the packing after the impregnant isapplied thereto, the fibres of the fabric strands being cut posed-by this operationfi p t Although the knowncup packingshave served satisfactorily, at least for th'emostfpart, under. 85 previous conditions ofuse it has recentlybeen found necessary to increase the. pressure against ton and cylinder assembly employing acup pack- 20 .ing of the present invention;

Fig. 2 isa fragmentary view, partially in perspective and partiallyfin section, illustrating a packing cup, embodying the present invention; and Fig; 13 is a fragmentary perspective viewillustrating'a feature of the invention.

Referring now particularly to Fig. 1, the'piston cylinder assemblyillustrated is of generally conve ntionaldes'ign'and comprises'a suitable, dou- 30 .and'their interstices lexble actin'g piston l0 carriedby piston rod H and 7 adapted for reciprocation Within a cylinder 12. W

'A double acting piston such is conventionally employed, particularly in has been illustrated, as

power reverse: gears.

It will lie-understood; how- -3 ever, that the cuppackings' of' the present inwhich the cups work. It has been discovered that the increased pressure causes the air or other fluid under pressure within'the cylinder to enter 40 the minute interstices of the fabric stran'dsex po'sedby punching or drilling of the bolt I a v I I Y jnular form onwhich rests the base of a cup packholes -.thegfiiiid wicking through the strands,-un-

"impeded" by the rubber or "other impregnant v which surrounds the strands-with:-consequent s loss of the pressure' in the cylinder. This loss of in no way limited to use with assemabove referred totype, butmay be employed as'well with jsingle'a'cting pistons and in piston cylinder assemblies forvaried purposes. 40

The pistonlil includes a head or seat 13 of anvention are blies of the Ill have theirjlips or'fianges '25 oppositely directed,'asindicated. A keeper ring il restsupon thelbase of the secondcup packing and bolts or 18 extend through I the keeper plate,

jspreaderringland cup packing bases,.and into A- further disadvantage. of the known type of t cup packings resides in the relatively frequent as failure of the lip or flange of the cup to seat in threaded engagement with the piston headl3. The bolts ,or studs carry nuts or heads 19 in jambing engagement with the keeper plate,

whereby the "several elements of the piston are held firmly together assembled relationship.

when reference is made to the1 The flanges or lips of the cup packings are forced outwardly against the piston walls by expander rings 20, the latter being of any suitable and conventional construction.

Referring now to Figs. 1, 2, and 3, the cup packing, in accordance with the present invention, is illustrated which comprises a base I6 and the lip or flange 25. The flange 25 and an annular portion 2| of the base I6 adjacent the flange are preferably formed of a laminated asbestos fabric suitably impregnated with a material, such as rubber composition, the impregnated fabric being suitably the same or similar to that heretofore conventionally employed for cup packings. innermost portion of the packing is preferably formed of similar material. nular portions 2| and 22 composed of the multiply impregnated fabric, an annular ring 23 is provided formed preferably of a rubber composition or other suitable plastic compound adapted to become readily distorted under pressure.- The reenforcing fabric is preferably entirelyomitted from this portion, and, in any event, no continuous fabric or strands are included.

, The annular ring 23 includes perforations or bolt holes 24 for'the reception of the securing bolts or studs I8, previously referred to. As

\will readily be understood, the location of the bolt holes in the ring 23 containing no fabric continuous with that of the rings 2| and 22, and preferably formed substantially entirely of the rubber or other plastic composition, insures against the presence of the exposed ends of continuous fibres or threads in the walls of the bolt holes, when the latter are punched or drilled in accordance with the desired present practice. In this way, porosity leakage is wholly done away with, air or other fluid maintained under pressure by the piston being prevented from entering the pores of the fabric of either ring 2| or 22. The deformable character of the material of the ring 23 further results in the provision of a tight seal around the bolts or studs l8, the

plastic material flowing against the bolts as the nuts are tightened down. The fabric rings 2| and 22, due to their relatively non-yieldingproperties. confine the plastic ring 23 and prevent undesirable distortion thereof.

Thus, the construction, in accordancewith the invention, fully overcomes the disadvantages of the prior cup packings with respect to porosity leakage, secures additional advantageswith respect to scaling at the bolts, and at the same time retains the strength of the prior type and per- .mits the punching or drilling of the bolt holes in the conventional manner. I

In accordance with a further feature of the present invention, the lip or flange l6 of the cup packing has, formed in the face thereof adapted for engagement with the cylinder wall, suitable annular ridges 26 providing annular grooves or valleys 21 therebetween. This construction provides lines of contact between the flange of the cup and the cylinder wall, whereby the flange of the cup is very quickly seated I with consequent substantial reduction of air leaking with the piston, the grease serving to lubri-.

cate the cupsindefinitelyv in service.

An annular ring 22 forming the Between the two an- Having now described my invention in rather full detail, it will be understood that these details need not be strictly adhered to, but that various changes and modifications will suggest themselves to one skilled in the art, all falling within the scope of the invention as defined by the subjoined claims.

What I claim is:

1. A cuppacking for assembly with a reciprocable piston including packing retaining means, said cup packing comprising a base and a pcripheral upstanding lip, said base comprising an annular section including fabric material carrying a yieldable impregnant and an annular section formedof a yieldable plastic material, said last-named section including perforations for the reception of said retaining means.

2. A cup packing for assembly with a reciprocable piston including packing retaining means, said cup packing comprising a base and a peripheral upstanding lip, said base comprising an annular section integral with said lip and including a fibrous fabric material carrying a yieldable impregnant and having minute pores in the fibres thereof, and an annular section formed of a yieldable plastic non-porous material, said last-named section including perforations for the reception of said retaining means.

3. A cup packing for assembly with a reciprocable piston including packing retaining means, said cup packing comprising a base ,and a peripheral upstanding lip, said base comprising spaced annular sections formed of fabric maimpregnant, anda third annular section interposed between said first-mentioned annular sections, said last-named annular section being formed of a yieldable, plastic material and including perforations for the reception of said retaining means.

5. A cupipacking for assembly with a reciprocable piston including packing retaining means,

said cup packing comprising a base and a pcripheral upstanding lip, said base comprising spaced annular sections formed of fabric material carrying a rubber-like impregnant and an annular section interposed therebetween, said last-named annular section including perforations for the reception of said retaining means.

6. A cup, packing for assembly with a reciprocable piston including packing retaining means, said cup packing comprising a base and a peripheral upstanding lip, said base comprising an annular section integral with said lip and including a, fibrous fabric material carrying a rubber-like impregnant and having minute pores in the fibres thereof, a second annular section formed of fabric material carrying a rubber-like impregnaniyand a third annular section interposed between said first-mentioned sections, said last-named annular section being formed of a r-like material and includin perforations -for the reception of said retaining a 7. A cup packing for assembly with a reciprocable piston includingpacking retaining means, said cup packing comprising a base rand a peripheral upstanding lip, said base comprising a" fabric material carrying a yieldable impregnani;

and including a section formed of a yieldable non-porous plastic material, said section including a perforation for the reception of said *re+ taining means. a m

8. A cup'packing for assembly witha recip- 1 a rocable piston including packing retainingmeans,

said cup packing comprising a base and a pe-.

ripheral upstanding lip, said base comprising a fabric v-rnaterial carrying a rubber-like impreg-t -nant and includin iasection'fonned 01a rubber-like'yieldable plastic material, said section including a perforation for the reception of, said retaining'means. I a

9. A cup packing for assembly with'a reciprocable piston including packing retaining means,

said cup packing comprising a baseand aperipheralppstanding lip, said base comprisinga fabric material carrying ayieldable impregnant and including-a section formed 0! ayieldable non-porous plastic material, said section in'cluding perforations for the reception of said fastening means. v r

GEORGE CHRJSTENSON.

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