US2465175A - Double wall washer or packing cup - Google Patents

Description

March 22, 1949.

E. l. SCHWARZ ETAL DOUBLE WALL WASHER OR PACKING CUP Filed March 17, 1948 Fla. 1

2 Sheets-Sheet l INVENTORJ RNES7' .ZI SCHWARZ AT TORNHS arch 22, 1949. 51.1. SCHWARZ ETAL, 1 2,465,175:

DOUBLE WALL WASHER OR PACKING CUP Filed March 1'7, 1948 2 Sheets-Sheet 2 F966 Fm. 9

INVENTORJ I fRNEST .2 .SmwARz BY AND 5950.5. JZ'l/AWEZ Arron/ways Patented Mar. 22, 1949 DOUBLE WALL WASHER OR PACKING CUP Ernest I. Schwarz and Fred B. Schwarz, Middletown, Conn, assignors to The Eis Automotive Corporation, Middletown, Conn, a corporation of Connecticut Application March 17, 1948, Serial No. 15,328

2 Claims. 1

Our invention relates to that class of devices known as double wall washers or packing cups and more particularly to the type referred to as the Chevron type packing cups. It is wellknown that double wall washers or packing cups are extremely efficient and are a great improvement over the prior packing rings. Reference hereafter to cups is intended to include both double wall washers and packing cups.

It is also known that the Chevron type cups are adaptable to special uses where the lip contact on the casing side and the journal side are less in area than the entire side walls of the washer.

Because the Chevron type cups have relatively thin lips, additional pressure is required to force these lips into fluid tight contact with the journal or cylinder or casing walls when there is little or no fluid pressure being exerted in the groove or out of the washer.

The weakness of the present Chevron type cups of which we are familiar is that when employed in hydraulic brake systems the outside lip is so flexible that seepage of fluid ofttimes occurs past the walls of the packing before any pressure is applied to the system.

Experience has also determined, because these cups are normally made slightly larger in lip circumference than the cylinder in which they operate, that when they are inserted in place the washer has its lip compressed to a degree that causes the base of the washer or cup to rise slightly, allowing seepage of fluid thereby. Consideration of the structure of the Chevron type cup will show that as the lip is compressed a hinging action necessarily occurs that lifts the base of the washer. This lifting of the base of the washer permits fluid to pass and ultimately to become deposited on the brake linings.

The pressure required to maintain fluid tight relationship between the cylinder wall and the lip of the packing we term the initial seal.

There are many devices to produce this initial seal available on the market.- We are familiar with the use of springs, resilient bands of metal, the impregnating of the material of which the washer is formed with stiffening rods, fabrics, spirals, etc.

All of these auxiliary devices are objectional for obvious reasons. For instance, contracting springs placed in the cut or groove of the cup will tend to tighten only the inside wall, or, if expanding springs are used, the contrary will result and only the outside wall is strengthened. If a soft metal ring with resilient fingers is inserted in the out or groove to lend strength to the lips of the cup, then, besides the difficulty of maintaining such a soft band in its desired shape, the metal tends to shield the rubber (if that is employed) from the effect of hydraulic pressure except between the fingers which is apt to cause distortion. An additional objection to the moulding of strengthening materials in the body of the packing cup is that its flexibility is interfered with and full performance becomes unlikely if not impossible.

It is well-known that double wall or Chevron" type cups are also desirable to be used on revolving or reciprocating shaft installations for oil or grease seals where no pressure is present. A few examples are in water pump shafts, automobile axles, transmission end shafts on machine tools and all types of machinery where lubricants or fluids are to be held in casings or containers, etc. One of the present means of accomplishing this result, that we are aware of, is, to provide a helical spring that tightens the inside wall of the washer around the shaft. Obviously this causes wear on the washer at this point and results in rapid deterioration.

In every hydraulic brake system we know of, some means inside or outside of the cup itself is employed to provide the initial seal required before fluid pressure is applied by depressing the brake pedal. The static pressure always maintained in such a system merely causes the seepage complained of without lending aid by being sufficiently strong to expand the lips of the cup. In revolving or reciprocating shafts or the like where no fluid pressure is available, this seal is especially necessary. As far as we know, no satisfactory means has been yet developed by the prior art to mould into the washer or packing cup this strength required'without adding foreign material thereto or making the washer so stiff as to destroy its resiliency with the result that the device fails in commercial practice.

It is the principal object of our invention to provide a double wall or Chevron type cup in which the lips are strengthened sufficiently to provide the initial seal to make the cup fluidtight without the presence of foreign bodies.

A further object of our invention is to providea double wall washer or packing cup that is strengthened to provide the initial seal by like material moulded integrally with the cup.

A further object of our invention is to provide a double wall washer or Chevron type packing 5 cup whereby additional pressure is exerted on the outside lip of its peculiar construction.

A further object of our invention is to provide a double wall washer or Chevron type packing cup wherein radially extending ribs are moulded integral with one wall only.

A further object of our invention is to provide a double wall washer or Chevron type packing cup wherein the stiffness of the walls may be increased or decreased proportionately to the frequency, shape anddepth of connecting ribs.

A further object of our invention is to provide a double wall washer or Chevron type packing cup wherein wedge-shaped radially'extending' or only one side wall of said washer.

A further object of our invention is to provide a device of the character described'that is easily and economically made yet is efficient and variable as the work requires.

The still further object of our invention isto provide a double wall washer that willbe soft; pliable, and resilient atthe same time suificiently lugs are moulded integrally with both side walls expended so that the liquidtight pres'sure for the initial seal is exerted withoutthe aid of fiuid' pressure.

still: further object of our invention is to provide adouble wall washer wherethe wallsare supported by ribs between them and are yet su'fiiciently pliable to be resiliently expandable.

Our means of accomplishing the'foregoing objects may bemore'readily understood by having reference to the accompanying drawings in which; 1 1

Figure l is a plan view showing the connecting ribs.

Figure 2 is a side elevation.

Figure 3 is a fragmentary sectional view, taken on line 3.-3, Fig. 1, showing" a connecting rib extending less than full depth of the cut.

"Figure 4 is fragmentary sectionalvi ew similar to 3 showing the connecting rib extending the full depth ofthecut.

Figur'e S is a fragmentary sectional view of another form of packing cup.

Figure 6 is a fragmentary sectional view of a modified form ofrib.

Figure '7 is a fragmentary plan view of an additional modified formof packing cup.

"Figure 8 is a fra'gmentarysectional view of an additional variation in the form of a double wall packing cup.

Figure 9 is a fragmentary sectional view of stillanother form.

Figure 10 is a fragmentary sectional view a variation of the form in Fig. 7.

Figure 11 is the reverse of Fig. 10.

Figure 12 is a fragmentary sectional view of our packing cup employed in an automobile axle shaft assembly.

"Figure 13 is a fragmentary plan view of an additional modified form of packing cup.

Figure l lis a fragmentary sectional view showing our invention applied to cups as in Fig. 13.

Similar reference numerals refer to similar parts throughout the entire specification.

As shown in the drawings, our invention comprises a packing cup body 2 with an inside wall 4 and an outside wall 6. This is preferably constructed with connecting ribs 8 extending into the groove or cut 9 between the inside walls In and I2. lhese ribs 8 may be moulded in the washer. As shown, we prefer to make them of the same composition as the washer 2. With this const:uction we strengthen the walls of our washer in varying degrees by varying the height the ribs extend. Under some conditions of work,

we extend the ribs substantially the full depth of the groove or cut 9 as shown in Fig. 4. Under other conditions, the ribs need not extend the the full distance of the cut 9 as shown in Fig. 3. Thus it will be clear that we have been able to adapt our invention to a full range of requirements by varying the size, frequency and thickness of the supporting members.

'Referring to Figs. 5, 6, 8, 9, 1 13 and 14 we have shown our invention of providing connecting ribs as applied to various shaped double wall washers or packing cups to provide the initial seal and to strengthen the lips so that they form fluidtight pressure.

Attention is invited to the structure of Fig. 12 wherein we have shown my cup applied to a form of rear axle assembly wherein the entire seal is dependent upon the structural strength of the inner lip Q6 of washer 30 as it embraces the shaft 28 at the outer end of casing l8 of a rear axle housing a backing for a wheel bearing. This and isprovidecl with-threaded'holes 22' to receive screws 24 which clamps the'keeper 26 in'place' for holding the-packing cup 30. The wheel beai ing aperture 28 is adapted to receive our Washer 39 which is supported at its base- 25 by abutting the wheel bearing 32 and at its outside wall21- by the inner wall of casing I8. It is clear inthis construction no fluid pressure is available to aid the fluid seal of lip 16. Y I

Referring to Figs. '7, 10 and 11 we have shown a further modification of our invention in-the form of wedge-shaped members. The space I9 between the'wedgesl'd is where hydraulic pressure is exerted. In the form shown in Figs; 10 and llwe have moulded the wedges in-the form of cleats moulded integrally with one wall but not attached to the other. This variation permits the further flexing of the free wall until it is compressed and abuts the free end'of the-wedge or cleat. As shown We prefer to mould the ribs in an odd number so that uneven'pressure is exerted thereby avoiding a possible cupping. Of'course constructionof even number of ribs may be accomplished without departing from this in vention.

It is clear that by increasing the area of the surface the hydraulic fluid acts upon; greater pressure is exerted-on that wall due-to the compressibility of the washer or cup. Thus in Fig. 'l by narrowing the aperture IS in which the by draulic fluid operates, the increase in area'of surface presented to the action of the fluid pressure increases the force that acts on the lip 6 since the tendency of the sides l3 and I5 under hydraulic pressure is to press inwardly and this naturally tends to push wall 6 outwardly.

Care must also be exercised to place the ribs 8 or the wedges M at properly spaced intervals depending upon the number employed or a cupping tendency will develop when the lip 6 of the washer or cup is compressed inside a cylindrical wall, due to the increasing resistance to compression that is exerted by the ribs 8 or wedges M.

It is clear that if desired the ribs 8 may be of a different composition than that of the wall mate rial. I If rubber is used, the ribs 8 could be made of harder rubber than the walls and vice versa. The shape of the ribs may be varied from the relatively thin segments 8 as shown in Fig. l to a few large wedge-shaped members [4 as shown in Fig. 7 if desired. Each typeof work is anticipated and is accomplished by our invention in which we vary the rib structure as desired and explained above. For special work we may provide the structure of Figs. 13 and 14.

The outstanding benefit of our invention is the fact that no unequal pressures are exerted upon the body of the washer by the presence of foreign bodies inside the cut of the washer.

Having described our invention, what we regard as new and desire to protect by Letters Patent is:

1. A unitary packing comprising a flexible annular body of resilient material, said body having a closed base of substantial axial thickness, inner and outer axially extending walls each having a substantially constant thickness considerably less than the axial thickness of said base to render said walls relatively flexible as compared with said base, said walls diverging with respect to said base and terminating in a pair of spaced sealing lips, the outer or said walls having a peripheral surface at least a portion of which flares radially outwardly with respect to the axis of said body, and a plurality of reinforcing webs integral with said body and interposed between said lips defining a plurality of cells therebetween, each of said webs being symmetrical with respect to a radius of said body.

2. A unitary packing comprising a flexible annular body of resilient material, said body having a closed base of substantial axial thickness, inner and outer axially extending walls each having a substantially constant thickness considerably REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 685,818 Close Nov. 5, 1901 1,038,642 Perry Sept. 1'7, 1912 1,802,177 Knight Apr. 21, 1931 1,899,695 Johnson Feb. 28, 1933 1,969,008 Hubbard Aug. 7, 1934 2,252,240 Tschappat Aug. 12, 1941 FOREIGN PATENTS Number Country Date 551,152 Great Britain 1943

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