US2283238A - Method of manufacturing thin rubber articles - Google Patents

Description

y 1942-. R. E. THOMPSON 2,283,238

METHOD OF MANUFACTURING THIN RUBBER ARTICLES Filed April 9, 1940 Fetented May 19, 3%2

entree srsrss stones s hereunto rm enriches hey E. Thompson, Nyaclr, N. Y asslgnor to horicg llmhoretories line, Jersey @ity, N. .lL, e corpora new and useful improvements in the method of manufacturing such articles. The invention relates more particularly to improvements in the art of making sanitary elastic sheaths by the dipping process, the sheaths being formed by a sheath proper and a band integrally attached thereto at its opening. In accordance with these improvements, elastic bands of predetermined size and elasticity may be provided at the open ends of finger cots, thumb guards, rubber gloves, breast nipple sheaths, and other hollow elastic sheaths-of a similar nature, in which the opening is substantially smaller in cross-section than the sheath itself.

In sanitary elastic sheaths oi the kind contemplated, little. or no reliance is placed on the sheath proper for attachment to the body. The

sheath proper is merely intended to cover a part of. the body, and depends essentially and primsrily on its built-in elastic band for attachment to the body. The band is alone sufllcient for the p se, and this leaves the sheath free for its intended sanitary purpose. The sheath protects the part covered from contamination by outside sources; and prevents contamination of other parts by the part covered. The sheath is particularly useful in preventing loss or discharge Y of medication from the part covered to surrounding parts. The sheath is also useful in functioning as a. cover and a support for a bandage or other cover placed over the aflected part. The sheath may contain an absorbent, such as gauze, cotton, or the like, with or without medication, for treating the port affected.

It is important that the opening of the hollow elastic articles be suitably reinforced. To accomplish this result, it is the practice in some cases to roll the elastic material at the opening into a. bead. While a roundbead of this kind is satisfactory for some purposes, it is highly disadvantageous for others. For example, when the article is tightly fitted over a part of the body, such as a. thumb, finger, wrist, breast nipple, etc., so as to be securely attached thereto, the rounded .bead tends to dig into the fleshin an uncomfortable and painful manner. It is also dimcult to control the elasticity of 2. rolled bead; the

larger the head in cross-section, the less readily,

it stretches. If, therefore, the bead is rolled to a.

size sumciently large to inhibit painful. digging into the flesh, it will often lose its desired elasticity.

I have found that the disadvantages of the 19%, Serial No. 328,661

((Dll. 18- 58) rounded bead may for the most part be avoided by reinforcing the opening of the hollow article with an especially added elastic band that is fiat orsubstantislly hat; and a band may be selected which will not painfully dig into the flesh and which will at the some time remain securely attached to the body. Having decided on a band of optimum width, thickness and elasticity, the manufscturer may be assured that after the band is integrally attached to-the hollow elastic article at its opening, the band portion of the article will have the desired characteristics.

The provision of an elastic band integrally attached to a hollow elastic article is, however, considerably complicated when the cross-section of the band is substantially smaller than the crosssectionel area. oi the hollow article. This is especially true of elastic sheaths or bass made by the dipping process, in which the sheath has 29 an opening very much smaller in cross-section than the sheath proper. A form, having sub: stentially the size and shape of the article to be formed. is dipped into a. suitable coating liquid. The coating remaining on the form must be removed, and therein lies the dimculty when the coating is to be integrally secured to an elastic band. As a result of my investigations, I have discovered improvements in method and apparatus which make it possible integrally to attach an an elastic band of predetermined characteristics to a thin elastic hollow article at its opening.

The invention will be more fully understood by referring to the accompanying drawing, taken in conjunction with the following description, in 35 which:

Fig. 1 is a diagrammatic representation of a shaft, showing an elastic band suitably mounted around one end thereof, useful in a. practice of the invention;

2 is a. similar view, showing a head preliminarily mounted on the shaft of Fig. 1;

Fig. 3 is a view similar to Fig. 2, but showing the head and elastic band in final position on the shaft;

Fig. 4 is a view similar to Fig. 3, showing the head, elastic band and shaft assembly immersed in a body of coating liquid;

Fig. 5 is a, cross-sectional view 5-5 of Fig. 2;

Fig. 6 is a. cross-sectional view on theline 6-6 of Fig. 4;

Fig. '7 is a cross-sectional view of the assembly in part showing the head, its coating and the band as a. unit separated from the shaft; and

Fig. 8 is a diagrammatic representation illuson the .line

-,fitted onto the shaft.

trating the removalof the elastic bag from the head.

Referring to Fig. 1, the apparatus shown comprises a shaft l0, preferably made of metal, such as aluminum, the head-end of which has a tapered section H extending from the main body of the shaft to a tapered end or tip portion l2.

' This figure also shows an elastic band l3 suitably placed in approximate position over the tapered r head-end of the shaft. The other end I! of the shaft is threaded so as to be screwed in a base I5 and to accommodate a lock nut Hi. This permits adjustment of the length of the shaft extending from the base.

Fig. 2 shows a head i1 having substantially the size and shape of the finished article, in this case an elastic sheath several times larger in crosssectional area than the cross-sectional area of its opening. The head, like the shaft, is preferably made of metal, such as aluminum with a polished, smooth surface. As shown in this figure, the head is mounted over the tapered portion of the shaft in, and the head engages the nearest rim of the band l3.

In Fig. 3, the head is shown mounted in final position on the shaft. As the head is moved down the shaft, the head pushes the annular band down the shaft into its final position. While this occurs, the rim of the band is and remains in contact with the head.

Referring to Fig. 4, the apparatus described is shown with the free end of the shaft extending upwardly and the head-end of the shaft, at least so much of it as is covered by the head. and the band, submerged in a body of suitable coating liquid i8 confined in a container iii.

The construction of the head and shaft is shown more particularly in Figs. 5 and 6. The head is provided with a shaft-opening 20 adapted to receive the head-end of the shaft. The fore portion 2! of the shaft-opening has a diameter substantially the same as body of theshaft, so that the head may be snugly The shaft-opening also contains a tapered portion 22 complementary to the tapered portion H of the shaft. The bottom of the shaft-opening is a practically straight wall portion 23 adapted to receive the tapered tip portion l2 of the shaft.

The shaft is provided with an air vent passageway 24 extending from the tip of the head-end of the shaft longitudinally through the center portion of the shaft, and ending as an opening 25- in the side of the shaft at a distance sumciently. removed from the final resting place of the band; on the shaft so as not to be covered by coating liquid in the dipping process.

In the arrangement shown in Fig. 5, the head is preliminarily placed over the shaft and is brought in engagement with the rim of the annularband across the tapered portion ll of the shaft; whereas in Fig. 6 the head and elastic band are shown mounted in final position on the shaft, with the headand part 0f.the band submerged in the coating liquid.

The shaft is adapted to support the'elastic' band at the line of juncture 26 (see Fig. 6) between the two when the head is mounted on the shaft. The shape of the head is such that a snug fit is provided between the head and shaft at the line of juncture, so that coating liquid cannot seepinto the shaft opening. The head and band rim are also in close contact with one another so that coating liquid cannot penetrate to the shaft that of the main adhere thereto. of the head comes substantially to a sharp line of intersection with the surface of the shaft opening in the head so that the edge 2] (see Fig. 8) effectively permits engagement with the rim of the band mounted on the shaft. The band may then in turn be pushed forward on the shaft while frictionally supported by the shaft.

. The surface 28 of the head at and near the entrance of the shaft-opening 20 tapers away from the shaft at an angle, preferably less than 90, sufficiently small to prevent a substantial build-up of rubber at the annular line of juncture 29 between the head and the elastic band, when the assembly is dipped in a body of coating liquid. With an angle of the degree contemplated, ex-

cess coating liquid may readily drain away from the band. If there should be a substantial buildup of rubber, it would of course alter the elasticity characteristics of the band portion of the sheath.

7 Fig. '7 shows the head, its adhering coating and the elastic band as a unit, from which the shaft has been separated or removed. The dotted outline in the figure shows the position previously occupied by the shaft.

The apparatus may be used as follows in the practice of the invention. The annular elastic band I3, preferably of predetermined width, thickness and elasticity, is freely dropped over the tapered portions i2 and ll of shaft ill. The internal diameter of the band is the same as that of the sheath when finished, and is substantially the same as the outside diameter of the shaft. When the band is dropped around the shaft in this manner, it engages the shaft frictionaily and assumes what may be deemed a preliminary position.

The head H, which has the size and shape of the sheath proper, is then fitted over the tapered portions l2 and ll of the shaft, as shown inFigs. 2 and 5. The head engages the nearest rim of the elastic band, and as the head is pushed down the shaft, the When the head is brought in final position on the shaft, that is, when it is securely attached to the shaft, the head and band assume the position shown in Figs. 3, 4 and 6, in contact with one another. During the mounting operation, air trapped in the shaft-opening 20 is vented through the passageway 24 to the outside atmosphere, in amount sumcient to prevent the building up of pressure.

With the base end of the shaft extending upwardly, the head and band are submerged in a suitable coating liquid, such as liquid rubber latex, liquid rubber, or liquid rubber cement, etc. The head is permitted to remain submerged until a thin coating of the liquid adheres to the head and the outside of the annular band.

The shaft and head are then withdrawn from the body of coating liquid, and the entire assembly is preferably placed in a drying room maintained at an appropriate temperature. If desired, and this is sometimes the preferred practice, the shaft and head assembly is subsequently returned for another dipping in the coating liquid, so that a second coating may be built onto the first coating; after which the shaft and head assembly is again returned to the drying room. This procedure may of course be followed as often as is necessary to produce a sheath of desired properties.

After the coating on the head and elastic band and has been suitably treated in this manner, the

To this end, the outer surface I band is also moved along the shaft.

aaeaaee by grasping the head with one hand and the shaft with the other, and then pulling the two apart. Since the coating on the head is integrally attached to the band, the coating and band remain with the head as the shaft is pulled through and away from the band.

Since the band extends freely away from the head at its opening, as shown in Fig. 7, it provides a most important means for removing the resultant elastic sheath or bag from the head without injury to the sheath. The elastic band portion of the sheath is suitably stretched into an enlarged opening and the head is removed. One method of removing the head from the sheath is illustrated in Fig. 8. The operator, for example, places his'right thumb 3d at the base of the coated head, and inserts his right fore finger 3|, as well as his left fore and middle fingers 32 and 33, into the interior of the annular band in any desired order. The three fingers are pulled apart and shoved deeper into the interior of the sheath as it separates from the head. The elastic band portion of the sheath is stretched in this manner until the opening is suiiiciently large to permit the expulsion of the head therethrough. This is accomplished by shoving the thumb 30 toward the fingers.

Special precautions are taken to remove stickiness from the inside and outside surfaces of the sheath. To this end, the head, coating and band,

assembly, as shown in Fig. 7 with shaft removed, is dropped into a body of suitable powder, such as talcum or other appropriate material .wellknown to the art. The powder promptly removes the stickiness from the outside surface of the coating. The operator then grasps the assembly, as shown in Fig. 8, and expels the head through the enlarged opening of the elastic band portion, preferably while the entire assembly is under the powder. As the head is propelled through'the enlarged opening, the sheath is turned inside out, thus assuring contact of powder with both sides of the sheath.

The sheaths are then picked out of the powder, shaken to remove excess powder and are appropriately packaged. If imperforate sheaths are desired, it is advantageous to test for pin holes by blowing them up with a certain amount of air.

I claim:

1. In the method of manufacturing elastic bags by the dipping process, the bag being, formed of a bag proper and a band integrally attached thereto at its opening, and the opening being substantially smaller in cross-section than the interior of the bag when both are unextended, the steps which comprise placing an elastic band about one end of the shaft, mounting a head having substantially the size and shape of the bag proper on said end of the shaft, bringing the head in final position on the shaft in contact with the nearest rim of the band, with the opposite end of the shaft extending upwardly dipping the head downwardly into a body of coating liquid up and onto the elastic band to form a thin coating over the head and onto and adhering to the band, and removing the resulting elastic bag with the elastic band integrally. attached thereto from the head.

2. In the method of manufacturing elastic bags by the dipping process, the bag being formed of thereto at its opening, and the opening being substantially small in cross-section than the interior of the bag when both are unextended, the steps which comprise placing an elastic band of substantially the size of the opening about a shaft having a diameter substantially as large as the opening of the bag, mounting a head having substantially the size and shape of the bag proper onto the head-end of the shaft, bringing the head in final position on the shaft in contact with the rim of the band -on the shaft, with the opposite end of the shaft extending upwardly dipping the head downwardly into a body of coating liquid up and onto the elastic band to form a thin coating over the head and onto and adhering to the band, withdrawing the shaft and head with its adhering coating from the body of coating liquid, separating the head together with its coating and the bandintegrally attached thereto as a unit from the shaft, suitably stretching the elastic band portion of the resulting elastic bag on the head into an enlarged opening, and removing the bag from the head by passing the head completely through the enlarged opening.

3. Method according to the preceding claim, in which the resulting elastic bag is treated to, remove stickiness directly before and afterthe head is passed through its opening.

4. In the method of manufacturing elastic bags by the dipping process, the bag being formed of a bag proper and a band integrally attached thereto at its opening, and the opening being substantially smaller in crosssection than the interior of the bag when both are unextended, the steps which comprise placing an elastic band of substantially the size of the opening about a shaft having a diameter substantially as large as the opening of the bag, mounting a head having substantially the size and shape of the bag proper and a rounded outer surface coming substantially to a sharp angular line of intersection with the surface of the shaft onto the head-end of the shaft, bringing the head in final position on the shaft in contact with the nearest rim of the band on the shaft, with the end of the shaft extending upwardly dipping the head downwardly into a body of coating liquid up and onto the elastic band to form a thin coating over the head and onto and adhering to the band, withdrawing the shaft and head with its adhering coating from the body of coating liquid, draining excess coating liquid from the annular band and the head to prevent excessive build-up of coating material at the line of Juncture between the two, separating the head together with its coating and the band integrally attached thereto as a unit from the shaft, suitably stretching the elastic band portion of the resulting elastic bag on the head into an enlarged a bag proper and a band integrally attached opening, and

removing the bag from the head by passing the head completely through the enlarged opening.

5. In the method of manufacturing elastic bags by the dipping process, the bag being formed of a bag proper and a band integrally attached thereto at its opening, and the opening being substantially smaller in cross-section than the interior of the bag when both are unextended, the steps which comprise placing an elastic band of substantially the size of the opening about a shaft having avdiameter substantially as large as the opening of the bag, mounting a head having substantially the size and shape of the bag proper and a shaft opening extending into the interior thereof onto the head &

end of the shaft,

I bags by the dipping pushing the elastic band with theheadalong the shaft while the head is being tightly fitted thereon, so as to leave the head in effective contact with the nearest rim of the band, with the end of the shaft extending upwardly dipping the head downwardly into a body' of coating liquid up and onto the elastic band to :fqrm a thin coating over the hand and onto and adhering to the band, withdrawing the adhering coating from the body of coating liquid, separating the head together with its coating and the band integrally attached thereto as a unit from the shaft, suitably stretching the elastic band portion of head into an enlarged opening, and removing the bag from the head by passing the head completely through the enlarged opening.

shaft andhead with its v the resulting elastic bag on the 6. In the method 01' manufacturing elastic process, the bag being formed of a bag proper and a band integrally attached thereto' at its opening, and the: opening being substantially smaller in cross-section than the interior or the bag when both are unextended,

the steps which comprise placing an elastic band of substantially the size 'of the opening about a shaft having'a diameter substantially as large as the openin of the bag proper and an air vent passageway, mounting a head having substantially the size and shape .of the bag proper and a shaft opening extending into the interior thereof onto the head-end of the shaft, bringing the head in final position on the shaft in contact with the-nearest rim of the band, venting air from the shaft opening in the head through said air vent passageway so that air pressure within the shaft opening is not set up to oppose tightening of the head on the shaft, dipping the head downwardly into a body of coating liquid up to and onto the band to form a thin coating around the head and onto and adhering to the band,

withdrawing. the shaft and head with its adhering coating from the body of coating liquid, separating the head together with its coating and the band integrally attached thereto as a unit from the shaft, suitably stretching the elastic band portion of the resulting elastic bag on the head into an enlarged opening, and removing the bag from the head bypassing the head completely through the enlarged opening.

- ROY E. THOMPSON.

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