US2754164A

US2754164A - Packing cup

Info

Publication number: US2754164A
Authority: US
Publication date: 1956-07-10
Anticipated expiration: 1973-07-10

Description

iinited States Patent G PACKING CUP Ernest I. Schwarz, Middletown, Conn., assignor to The Ens Automotive Corporation, Middletown, Conn., a corporation of Connecticut Appiication December 14, 1955, Serial No. 553,052

3 Claims. (Cl. 309-33) This invention relates to a pressure sealing device and, more specifically, to an improved packing cup of a type particularly adapted for application to the end of a piston or the like.

A conventional packing for the general purpose or application set forth above comprises a rubber or rubberlike cup having a fiat circular back wall and a forwardly diverging side wall or skirt. In a common installation or application, the back wall of the cup engages the end of a piston disposed within a cylinder or housing and the skirt, at least the forwardly projecting edge portion thereof, engages the cylinder or housing within which the piston operates. The said forwardly projecting edge portion of the skirt or lip is made on a slightly larger diameter than the diameter of the cylinder or housing so that the lip or skirt will engage the cylinder with at least some pressure. Pressure is necessary in order to maintain a fluid-tight relationship between the cylinder wall and the skirt. The amount of pressure necessary to maintain a fluid-tight seal will, of course, vary from installation to installation.

The pressure necessary to maintain the initial seal or the aforesaid fluid-tight seal in application of the conventional packing cup will compress the lip or skirt to cause the back wall to rise or cup slightly, allowing seepage or flow of fluid. Accordingly, the conventional packing cup described above has two serious disadvantages. The first such disadvantage is that it is diflicult to provide a single skirt which will exert suflicient pressure against the cylinder wall and maintain that pressure over a long period of life or use. The second disadvantage is that when a conventional cup is so fashioned to provide sufiicient sealing pressure on the lip or skirt, that pressure causes the back wall to rise or cup and permit leakage thereacross.

The same general disadvantages were at one time encountered in annular double wall washers or packing cups. Double wall annular packing cups are employed to exert sealing pressure against a cylinder wall and also to exert internally directed sealing pressure against the wall of a piston or shaft. The disadvantages of the old annular packing cups were overcome in accordance with the invention described and claimed in U. S. Patent No. 2,465,175 wherein I am co-patentee. In that patent, there is disclosed a double wall annular sealing cup wherein ribs are provided to extend between the inner and outer walls of the cup to reenforce said walls and exert the required sealing pressure against the cylinder wall and against the piston or shaft.

My present invention contemplates carrying forward to a piston end packing the advantages inherent to the double wall annular packing cup shown in the aforesaid patent.

It is the general object of the invention to provide a packing cup which is particularly adapted for application to the end of a piston or the like and which will exert the necessary sealing pressure against the Wall of a cylinder without permitting the cup to become distorted or displaced in any way so that fluid leakage can occur.

Other, more specific objects as well as advantages of Patented July 10, 1956 the invention will become apparent from a more detailed description taken in connection with the attached drawing wherein, by way of example only, two embodiments of the invention are shown. It will be understood from the claims forming a part of this specification that the invention is not limited to the specific embodiments shown in the drawing and, therefore, the drawing and the description thereof should not be taken as defining the limit or scope of the invention.

In the drawing:

Fig. 1 is a top plan view of a packing cup constructed in accordance with the present invention;

Fig. 2 is an elevational view of the packing cup;

Fig. 3 is a vertical sectional view through the cup and showing the support member disposed therein;

Fig. 4 is an elevational view showing the cup and support member in exploded relationship; and

Fig. 5 is a view similar to Fig. 3 showing an alternative form of construction and showing how the cups of this invention may be secured to a piston.

As shown in each of the aforedescribed views of the drawing, the packing cup of this invention includes a molded rubber or rubber-like element indicated generally at 10 and a rigid circular pan-like support member indicated generally at 12. In general appearance, the molded rubber member 10 is somewhat similar to the annular packing cup shown and described in Patent No. 2,465,175. That is, the molded rubber member 10 includes an outer skirt or lip 14 and an inner skirt or lip 16. The member It differs substantially from the annular packing cup shown in the aforementioned patent in that a flat circular back wall 18 encloses the member and provides a generally cup shape therefor. The outer wall or lip 14 projects forwardly from the back wall 18 and is tapered so as to diverge forwardly. The inner lip or wall 16 projects forwardly and extends beyond the outer wall 14. A generally V'shaped annular groove 20 is defined between the

skirts

14 and 16, the V-shape being defined by a forwardly converging outer surface 22 on the inner skirt 16 and a forwardly diverging inner surface 24 on the outer skirt 14 as shown best in Fig. 3. A plurality of molded integrally formed

ribs

26, 26 are equally circumaxially spaced around the molded cup 10 and extend radially between the

skirts

14 and 16 thereof. Obviously, the shape or configuration of the annular groove 20 and the

ribs

26, 26 and the slope or taper of the

surfaces

22 and 24 can be changed without departing from the invention.

As set forth in the aforementioned Patent No. 2,465,175, the ribs between the inner and outer skirts or lips provide reenforcing means which will bias the outer skirt into fluid-tight sealing engagement with the wall of a cylinder when the packing cup is applied therein. As also described in the said patent, the ribs exert force or pressure against the inner skirt or lip to bias the same radially inwardly. The ribs will exert the sealing pressure necessary to the lips and will, in the application of said pressure, prevent distortion of the cup due to the pressure applied.

The disk-like rigid support member 12, which is preferably stamped from the sheet metal, is disposed as best shown in Fig. 3 within the inner skirt or lip 16. That is, the rigid member 12 has a circular back wall 28 which engages or is seated against the back wall 18 of the rubber cup 10. The disk 12 also has a forwardly projecting rim or peripheral wall 30 which is snugly engaged against the inner surface of the inner lip 16. The inserted pan or disk 12 is secured within the rubber cup 10 by providing an inturned flange 32 at the forward edge portion of the inner lip 16 and which projects over the forwardly extending edge of the peripheral wall 30.

The packing shown in Fig. 5 is different from the previously described packing only in details of construction of the rubber cup member designated generally by the reference 10a and in details of the insert indicated generally at 12a. More specifically, the outer lip of the rubber cup 10a is extended forwardly equally to the innet lip and the rim of "the insert 12a is extended forwardly equally of the inner lip of the member 10a. In addition, the rubber cup 10a and the insert 12a are provided with

central apertures

35 and 37, respectively, which register with each other and which are adapted to receive a screw S to secure the assembled packing to the end of .a piston P. It will be understood that the first described embodiment of the packing and any other alternative forrn can be similarly secured by providing apertures as described. Obviously, packings constructed in accordance with this invention can be attached to the end of a piston or engaged therewith by any conventional and convenient means. For example, a spring A such as shown in Fig. can be seated within the support insert to bias the packing against the end of a piston.

In either of the forms shown, and in any alternative form, the packing is completely assembled by inserting the pan-shaped support vdisk within the packing cup. In the first described embodiment, the inturned flange 32 secures the disk in nested relationship within the cup, while in the embodiment shown in Fig. 5, the disk is merely retained by the inner lip of the cup engaging the rim of the said disk. In all forms of the invention, the disk is essential to assure a sealed fit. That is, the disk provides support and reenforcing means preventing inward displacement of the inner lip or skirt of the cup so that the compressive force is directed radially outwardly against the housing or cylinder wall in which the piston operates. Since the support disk or pan will not permit inward displacement of the inner lip of the rubber cup, it thereby prevents displacement or cupping of the back wall of the cup and it prevents any other distortion of the cup.

The invention claimed is:

l. A packing for sealing the end of a piston or the like within a cylinder and comprising a substantially circular rubber-like cup having a flat back Wall, a forwardly diverging peripheral skirt, a forwardly projecting annular lip spaced radially inwardly of the skirt, and also having a plurality of circumaxially spaced integrally formed ribs extending between the skirt and the lip, and a rigid support and reenforcing member disposed within said annular lip in engagement with the said back wall to prevent distortion and displacement thereof due to sealing pressure between the forwardly projecting portion of the skirt and the cylinder wall.

2. A packing for sealing the end of a piston or the like within a cylinder and comprising a substantially circular rubber-like cup having a flat back wall, a forwardly diverging peripheral skirt, a forwardly projecting annular lip spaced radially inwardly of the skirt, and also having a plurality of circumaxially spaced integrally formed ribs extending between the skirt and the lip, and a rigid support and reenforcing member comprising a substantially circular disk having a forwardly projecting peripheral wall and which disk is disposed within the annular lip in engagement with the said back Wall and with the peripheral wall engaging the said lip whereby to prevent distortion and displacement of the back wall due to scaling pressure between the forwardly projecting portion of the skirt and the cylinder wall.

3. A packing for sealing the end of a piston or the like within a cylinder and comprising a substantially circular rubber-like cup having a fiat back wall, a forwardly diverging peripheral skirt, a forwardly projecting annular lip spaced radially inwardly of the skirt, and also having a plurality of circumaxially spaced integrally formed ribs extending between the skirt and the lip, and a rigid support and reenforcing member comprising a substantially circular disk having a forwardly projecting peripheral wall and which disk is disposed within the annular lip in engagement with the said back wall and with the peripheral wall engaging the said lip whereby to prevent distortion and displacement of the cup due to sealing pressurebetween the forwardly projecting portion of the skirt and the cylinder wall, the said annular lip having a radially inwardly projecting flange at its forward edge portion which flange overlies the forward edge of the said peripheral wall to retain the support member in the aforesaid position.

No references cited.