US 1705455 A
Description (OCR text may contain errors)
March 12, 1929. T, m rr 1,705,455
PACKING GASKET AND METHOD OF MAKING $AIE Original Filed Adg. 25. 192'? 2 Shoots-Sheet l Inueior:
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March 12, 1929. r mm-ms 1,705,455
PACKING GASKET AND METHOD OF MAKING SAME Original Filed Aug. 25, 1927 2 Sheets-Sheet 2 Patented Mar. 12, 1929.
UNITED STATES PATENT OFFICE,
RICHARD T. GRIFFITHS, OI! AKRON, OHIO, ASSIGNOR TO THE MILLER RUBBER COM- PANY, OF AKRON, OHIO, A. CORPORATION OF OHIO.
PACKING GASKET AND METHOD OF MAKING- SAME.
Original application filed August 25, 1927, Serial No. 215,438. Divided and this application filed August 25, 1928. Serial No. 302,070.
My present invention relates to an improved packing gasket, and includes matter divided out of an application filed b'y me In the U. S. Patent Olliee on the 25th day of understood, refereneeis made to the accompanying drawings in which:
Fig. 1 is a perspective view showing a portion of a refrigerator door by way of example) and the manner in which my 1mproved packing strip is applied thereto.
Fig. 2 is a transverse section through the I strip on a line with one of the attaching devices.
Fig. 3 is a sectional view showing the manner of applying the strip.
Fig. 4 is a fragmentary section of mold showing the method of forming the strip.
Fig. 4 is a transverse section thereof.
Fig. 5 is a perspective view of one of the discs used to form the attaching means.
Fig. 6 is a sectional detail of a modified form of attaching means.
Fig. 7 is a similar view of a further modification.
Fig. 8 is a till further modification.
Figs. 9 and 10 are detail views illustrating the method of manufacturing the article of Fig. 7 and Fig. 11 is a detail view illustrating the method of making the article of Fig. 8.
Referring by reference characters to this drawing, the numeral 1 designates a closure member of the swinging type such as a metal refrigerator door having the flange portion 1 to which the packing strip is to be secured.
This is provided with a plurality of holes 1 spaced apart distances according to circumstances or as may be found most desirable.
2 designates the packing strip or gasket of sponge rubber and most desirably made of semi-cylindrical shape.
At distances corresponding to the spacing of the holes 1", the flat face of the gasket is provided with attaching devices in the shape of buttons or projections, each comprising a shank 3 of solid soft rubber and a diameter corresponding approximately to the diameter of opening 1", and enlarged head or flange 3 of a flexible character. Given such a construction, I have found that by the use of-a suitable tool such as indicated at 4, the strip including its attaching means may be so distorted from normal condition as to allow the flexible flange 3 to be poked or pushed through the opening 1 whereupon its inherent resilience will cause it to draw the flat face of the gasket into contact with the carrying plate and hold it firmly in position.
I have found that by making the attaching members of hollow form as shown in Fig. 3, the connection above described is facilitated. Such construction aids in economical manufacture by the following method which I have devised.
In Fig. 4, I have shown conventionally and in fragmentary form a three part mold comprising a lower or main member 8 having a mold cavity 8 of a shape conforming to the shape of the desired packing strip or gasket, a top member 7 and an intermediate member 6 having an opening therethrough the lower portion 6 of which is of a diameter corresponding to the diameter of the stem 3 of the attaching member while the upper part 6 is countersunk or of a diameter corresponding to the head 3 of said attaching member. A length of unvulcanized sponge rubber compound of a size insufficient to fill the cavity 8 is placed therein, mold member 6 applied, and a disc 3* of unvulcanized or partially vulcanized soft solid rubber compound (see Figs. 4 and 5), is placed in the rebated or countersunk portion 6" after which the top plate 7 is applied and the mold subjected to heat in the customary manner.
The heat softens the rubber disc which tends to sag into the opening and be pressed further therein by air or gases entrapped above the disc. As the heat is continued the sponge rubber compound expands by reason of the blower therein until it fills the mold cavity and contacts with the depressed portion of the disc or discs and the sponge rubber strip and cupped disc members are by the further heat vulcanized together into a single'unitary o'r homogeneous article of the shape shown in Figsl and 2.
Instead of making the button or attaching means of hollow form as above described, I
according to this figure, I provide a three 3 part mold as shown in Fig. 9 comprising top, bottom, and intermediate plates 9, 10, and 11, respectively, having a mold cavity of the shape of the attaching member or button and having a core pin 11 carried by the-upper plate and depending into the cavity, it being understood of course that in practice the mold would have a large number of such cavities for molding a plurality of articles in a single operation.
Sufficient rubber having been placed in each cavity to just fill the same when the mold is .closed, the closed mold is subjected to suflicient heat to partially vulcanize the button or buttons, whereafter the mold plate -11 is removed and placed between the mold plates 12 and 13, the latter having a mold cavity 13 corresponding to the cavity 10 while the plate 12 has a cavity 12 corresponding to the desired shape of gasketstrip.
The mold being subjected to proper heat, the sponge rubbercompound shown in the cavity expands and contacts with and surrounds the base flange of the button and projects part way into the hollow shank and is firmly united thereto.
.As a further modification, I may make the gasket strip and attaching means all-off sponge rubber as indicated at 3, Fig. 8, which may be accomplished by placing in the gasket cavity 14 of mold member 14:. sufficient sponge rubber compound to cause the rubber to be forced into the recesses which form the attaching members, said recesses being of the proper shape as indicated in connection with Fig. 7. It will be understood that the mold vulcanization produces a skin on the sponge rubber which gives requisite strength, but further stren th or stiffness may be imparted to the attaching means b molding therein a reinforce such as a tac d laced in the mold cavity and surrounded y the sponge rubber as it expands.
If desired, the mold of Fig. 9 may be a separate mold from that of Fig. 10 as an entirety, with the button forming cavities set closely together to increase capacity and the buttons thereafter transferred to another plate 11, Fig. 10, with the holes spaced apart the proper distance for gasket attachment. Having thus described my invention, what I claim is: l v
1. A packing gasket comprising a strip of cellular rubber having relatively stiff rubber attaching buttons homogeneously united thereto.
2. A packing gasket comprising an elongated strip of cellular rubber having an imperforate skin and a plurality of relatively stifi rubber attaching buttons homogene-