US2428406A

US2428406A - Method and apparatus for the manufacture of dipped rubber goods

Info

Publication number: US2428406A
Application number: US602873A
Authority: US
Inventors: John M Auzin
Original assignee: Davol Rubber Co
Current assignee: Davol Rubber Co
Priority date: 1945-07-02
Filing date: 1945-07-02
Publication date: 1947-10-07
Anticipated expiration: 1964-10-07

Description

Patented Oct. 7, 1947 'UNITED STATE METHOD AND APPARATUS FOR lTHE MANU'- FACTURE OF DIPPED RUBBER GOODS yJohn M. Auzin, lWarwick, R. I., assignorto 'Davol Rubber Company, a corporation of 4Island Rhode ApplicationJuly'Z, 19475, Serial No. 602,873

y The present invention relates to the manu- `facture of rubber articles, and has particular ref.-

`erence to the manufacture of pessaries and the like by dipping.

The principal object of theinvention is to provide a novel arrangement for facilitating the frmation of a roll edge on a pessary or the li e. A

Another object of the invention is to provide a vnovel arrangement which simplifies the rolling of the edge around a resilient core.

With the above and other objects and advantageous features in view, the inventionconsists of a novel form and a novel procedure for `.obtaining a roll edge on a pessary or -the like in. a simple and effective manner, more fully disclosed in the detailed description following, in conjunction with the accompanying drawings.

In the drawings:

Fig. 1 is a front elevation of a pessary having a roll edge formed in accordance with the invention;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a perspective View of the novel form for dipping, a resilient, coil spring being shown in position for forming the core; and

Fig. 4 is a vertical section through the mold, after dipping, with the roll edge partly formed.

The manufacture of pessaries and similar articles having roll or bead edges normally is accomplished by dipping a suitable form in natural or synthetic rubber in solution, such as latex, to vprovide the body of the article and an elongated skirt, placing a resilient core such as a coil spring over the lower edge of the skirt, and then rolling up the resilient core in the skirt so as to embed the core in the rolled up material and form a roll edge or bead. It has been found that a form of uniform diameter, such as is commonly used, causes the tension of the resilient core to increase as the roll edge builds up, and that the skirt, if in moist condition, will slide up and buckle ahead of the spring coil unless the tension is released. It has also been found that it is advantageous to form the roll edge when the skirt is in moist condition, as the bond between the resilient core and the enveloping material is firmer and a higher production results; whereas the formation of a roll edge after thorough drying of the rubber material requires time and additional handling, as well as reducing the strength of the bond.

I have therefore found it advisable to provide a form which has the usual pessary shape, for example, at the dipping end, and which has a.

2 Claims. (Cl. IIS-47.5)

Y 22 tapered lead towards the dippingV end, this tapered lead increasing in diameter just below the usual pessary roll edge groove, so that the resilient core, which is initially slightly distended, rst gradually decreases in diameter and then momentarily increases in diameter before entering the roll edge groove. The tapered lead facilitates the rolling process and. eliminates. sliding back of the skirt, andthe slight expansion before the roll edge groove is reached equalizes the tension in the core and smooths out the formed roll edges so that the roll edge, ,when within the groove, is of uniform tension, and. is symmetrical and smooth in shape, whereby the vfinished articles are uniform in shape, and. dry and cure without distortion.

Referring to the drawings, thepessary III includes a exible dome II and a roll edge I2 in which a resilient core I3, preferably a spiral wire coil, is embedded. A special form I4, see Fig. 3, is used for dipping, the form having a dome top I5, a roll edge groove I6, and a body portion I'I. The body portion has a lower groove I8 in which the resilient core is initially placed, and a tapered central portion I9 which is marked or scored, as indicated at 20, to disclose the dipping depth, this depth being about 1% inches for a 75 mm. pessary and about 11A inches for a smaller pessary. The tapered central portion I9 is initially of greater diameter than the roll edge groove, as indicated at 2l, then tapers down almost to the diameter of the roll edge groove, as indicated at 22, then abruptly enlarges, as indicated at 23 when closely adjacent the roll edge groove IB, to form a slight circumferential hump or ridge 24. The initial out taper should be about 1/2 inch, and the slope-in should be about 2% inches.

The form I4 is first dipped in latex or other rubber solution t0 the line 20, to obtain an elastic layer 25 having a depending skirt 25a, see Fig. 4, the thickness of layer found suitable being about .012 inch. The coil spring I3 is already in position in the groove I8, see Fig. 3, and is readily moved out of the groove and over the tapered central position I9, as the taper causes it to smoothly roll down, this smooth rolling down being facilitated and aided by the natural lcontraction of the coil spring, which is initially under slight tension when it passes over the enlarged region 2l. As the coil spring advances, aided by its contraction, it engages the lower edge of the skirt 25a, which rolls up also as shown in Fig. 4, until the reduced diameter region 22 is reached, this region being preferably of slightly l()` hump thus serves to uniformly distribute the lcoilV spring and the rolled up skirl'I s o that the roll edgegr;l

or bead which seats Within thegroove `IE is uni-:'1- 'l Yform inV size and is uniform in tension.

manufacture is completed byfdrying'andicuring; since the roll edge core is free when in the form' groove it becomes under adjusting tension when the pessary is cured. Y yThe novel method, by y thus produces a uniformly satisfactory'product',

- vas the resilient core'is first stretched, then its tension is released to becomeequalized, and the formed roll edge is sharply momentarily stretched too'btain a :close and uniformjoin between the rolled'up skirt material andthe resilient core :partsl Althougha wood form issuitable, a por- "celainform may be used, 'suitably markedk to [show Y the dipping depth.

" vAlthough I have described a VSpecific form and "a speci'prccedure'suitable for'the manufacture Thel .t

using the novel form,..

4 roll edge .containing a resilient core, comprising the steps of dipping a generally cylindrical form in rubber solution to deposit a layer thereon having a skirt, positioning a resilient circular core under tension over the edge ofthe skirt to Ibecome emfbedded in the skirt material, and forming albead by rolling the skirt edge andthe resilient core over the deposited layer, lfirst gradually releasing the tension of the core 'during' the rolling operation, then momentarily sharply increasing the core tension, and finally reducingv the .core tension4 at the completion of the rolling'. Y operation. L

2. A generally, cylindrical form for dipping" -irufbberand. rubber material articles having a.

roll edge or bead, comprising an upper dome end shaped to conform to the article, the body of .the form being Vreduced in diameter to provide a narrow annular groove below the dome end,V then 'being increased in diameter and again reduced in diameter to'provide a narrow humpv just :below the groove, and thenbeinggradually increased to a larger diameter than thediameter Y of the groove to provide an" elongated ski'rtjdifp-g offroll edge or beaded 'pessaries it is obvious that lotherjarticles of rubber or the like having 1ro-ll edges orjbeads maybe made, fthe forms'lbeing vdesigned tof correslond to the size and shape of fthe desired article.

u A1..11'he method of forming-anwarticlehaving "a 'terminal annular groove at ping portion, the Yelongated portionlhavinga" its lower-end.: "7* JOHN AUzI1\r.-f REFERENCES CITED The'followingreferences are of recordrin'the lle'of this patent: V

UNITED STATES PATENTS i