US2313792A - Method of making blood pressure bags and other articles - Google Patents

Description

March 16, 1943. G. WINDER METHOD-OF-MAKING BLOOD PRESSURE BAGS AND OTHER ARTICLES Filed Aug. 17, 1940 2 Sheets-Sheet 1 2-2 ENfUL 550292 L- ZZ/z'naaa.

March 16,1943. L, WINDER 2,313,792

METHOQ-OF-MAKING BLOOD PRESSURE BAGS AND OTHER ARTICLES Filed Aug. 17, 1940 2 Sheets-Sheet 2 550525 .2 MHUEJL.

Patented Mar. 16, 1943,

METHOD OF MAKING BLOOD PRESSURE BAGS AND OTHER ARTICLES George L. Winder, Cuyahoga Falls, Ohio, assignor to American Anode Inc., Akron, Ohio, a corporation 01' Delaware Application August 17, 1940, Serial No. 353,145

6 Claims.

This invention relates to hollow rubber articles provided with communicating tubes extending therefrom and especially to blood pressure bags embodying novel constructional features and to economical and efllcient procedure for manufacturing such articles. The invention will be described in detail with reference to the accompanying drawings of which:

Fig. 1 is a sectional elevation illustrating a preliminarystep in the manuiacture of a tube as sembly employed in the present invention and showing an auxiliary deposition form immersed in a liquid rubber composition for receiving a coating of rubber.

Fig. 2 is a perspective view illustrating a further step in the process and showing the tube assembly being removed from the auxiliary deposition form.

Fig. 3 is a sectional elevation illustrating a further step in the proces sand showing the tube assembly associated with a principal deposition form and the composite assembly immersed in a liquid rubber composition for receiving a coating of rubber.

Fig. 4 is a perspective view showing the composite assembly of Fig. 8 with a rubber coating thereon and further illustrating the step of slitting a portion of the coating to permit removal of the principal form.

Fig. 5 is an elevation illustrating thestep of removing the rubber coating from the principal deposition form.

Fig. 6 is a perspective view, partially broken away and sectioned for clarity of illustration, showing the coating after removal from the principal form and further illustrating a preliminary step in sealing the slit in the coating.

Fig. 'l is a sectional elevation illustrating a further step in sealing the slit and showing an end portion of the coating immersed in a liquid rubber composition.

Fig. 8 is a perspective view showing a finished bloodpressure bag made in accordance with the present invention.

Fig. 9 is a vertical section taken on line 9-9 of Fig. 5.

Fig. 10 is a fragmentary elevation, broken away and sectioned, showing an end portion of a blood pressure bag embodying a modification of the invention in which a reenforclng element is included in the region of the slit.

Equipment used by Physicians for determining the blood pressure of patients includes a unit known in the art as a blood pressure bag. Such blood pressure bags customarily are made of rubber or analogous material and include a generally rectangular flat hollow bag B and a pair of communicating tubes T, T extending from one of the longer edges of the bagat a position adjacent one end thereof as indicated in Fig. 8. According to the present invention, such a blood pressure bag is made by a process in which a tube assembly is first formed independently, after which the bag portion is formed in contiguous cohering relation with a portion of the tube assembly.

To form the tube assembly, I utilize an auxiliary deposition form indicated generally by the numeral Hi. The auxiliary form l0 includes a relatively small trapezoidalplate member i I provided with two rod-like stems l2, l2 extending fromone edge of the plate member H in the plane of the plate, the stems i2 corresponding in size and length to the interior diameter and length of the tubes desired in the blood pressure bag. The form i0 may have a supporting member such as the hook I3 extending from the opposite edge of the plate. To produce the tube assembly, the auxiliary form 10 is coated with rubl her as by immersing the form in a liquid rubber composition such as any suitably compounded latex L as illustrated in Fig. 1. Desirably the form I0 is pre-coated with a composition adapted to coagulate latex compositions as described in U. S. Patent No. 1,908,719, and such coagulant composition desirably should contain a powdery separating material. as described in U. S. Patent No. 1,924,214. The form i0 is completely immersed in the latex as shown in Fig. 1 and ispermitted to remain therein until a rubber deposit from .015 to .025" (when finished) has been deposited over the entire form. The form then desirably is raised until the liquid level of the latex is just below the edge of the plate member I i and deposition on the immersed stems I2 is then con tinued until the total rubber deposit on the stems is from .030 to .060" thick (when finished). Such continued deposition may be effected by progressive action of coagulant initially applied to the form, or'the stems I! may be re-dipped a number of times, either with or without intermediate coagulant treatments, to build up the desired thickness of rubber. The form in together with the deposited rubber coating is then removed from the latex and the rubber deposit is dried but not vulcanized. The rubber coating is then slit around the top edge of the plate I l to permit removing the tube assembly from the form as cated at I, 24.

parallel flaps. As will appear more clearly later,

the flaring member IE will constitute a'reinforcing element in the finished bag. To insure a neat product, the exposed end of the element It desirably should be trimmed smoothly as along the semi-circular dotted line shown in Fig. 2 and indicated by the numeral I6.

I then provide a principal deposition form including a main portion ll of generally flat rectangular configuration adapted to form the bag portion of the final product. The principal form also is provided with two rod-like stems l8, l8 which extend outwardly in the plane of the form from one of the longer edges of the main portion H at a position adjacent one end thereof as shown in Fig. 3. The stems l8 desirably should be somewhat longer than the rubber tubes ll of the prepared tube assembly, but otherwise should correspond in size to the tubes.

I next place the prepared tube assembly on the principal form by sliding the tubes l4 down over the stems l8 until the flaring flange or reinforcing element l5 embracesclosely the portion of the main form adjacent the bases of the stems l8 as may be seen more clearly in Fig. 3. Desirably the underside of the reinforcing element I5 is cemented to the form H by means of a thin coating of rubber cement or other suitable adhesive which will prevent seepage of liquid rubber composition between the two members during subsequent operations while permitting ready removal of the completed article including the element IS. A suitable supporting, clamp I9 is then attached to the extending ends of the stems I8 and the composite assembly of the principal form with the tube assembly thereon is immersed in a liquid rubber composition,

such as a suitably compounded rubber latex L, and a coating of rubber 25, for example, about .025" thick is deposited over the entire assembly including the exposed portions of the principal form and the outer surfaces of the tube assembly. As before, such deposition may be facilitated by the use of any appropriate coagulant for latex. The assembly with its over-all coating of rubber is then removed from the latex and the rubber is dried, but not vulcanized.

To permit removal of the principal form, I then slit a portion of the rubber deposit 25, preferably along the major'length of the shorter edge of the deposit removed from the tube assembly. Such slitting conveniently may be accomplished simply by progressively pressing a heated cutting element 20 or other suitable instrument against the rubber along the edge (Fig. 4) The principal form is then removed through the opening made by the slit by doubling the rubber coating back overthe form as shown in Fig. 5, and stripping the tubes from the stems.

To seal the opening made by .the slit, the cut edges at the slit preferably are coated with rubber cement or other rubber adhesive as indicated at 2| (Fig. 6) and the cemented edges are pressed into abutting relation. To insure against leakage at the seal and to reinforce the seal against failure when the bag is inflated, a reinforcing cap of rubber 22 is produced thereover as by immersing the end portion, for example about one inch, of the bag in latex L or other liquid rubber composition as shown in Fig. 7. This pro cedure may be repeated several times to build up a rubber cap of any desired thickness.

It is also possible to utilize a coagulant to produce a heavier cap with a lesser number of dips and the coagulant may be applied to the entire area to be capped or to a desired restricted portion thereof. In the latter case, the cap will be thicker over the area to which coagulant was applied.

Finally, the entire article is thoroughly dried and vulcanized by heating in the usual manner to produce a finished blood pressure bag as shown in Fig. 8.

For further reinforcing the seal at the slit, when desired, a strip of textile fabric 23 (Fig. 10) or other reinforcing material may be placed over the slit prior to application of the rubber cap 22, or the fabric strip may be interposed between any of the successive deposits constituting the cap 22. In either case, the fabric 23 preferably is pre-treated' with latex or other rubber composition to secure more perfect anchorage in the rubber.

It will be appreciated from the foregoing that a blood pressure bag or other article produced tubes T, T, extending therefrom and that the reinforcing element I5 is attached to the'interior face of the wall 25 of the bag and is continuous with the inner portion H of the tubes T, as more clearly shown in Fig. 9. The outer portions of the tubes T are continuous with the wall 25 of the bag B so that an unusually strong and essentially unitary structure is produced which effectively resists failure heretofore experienced at the junction between the tubes and the bag. Furthermore, the products of the present invention include a reinforcing cap over the slit at the end of the bag which insures effective sealing and reinforcement against failure upon inflation. The cap also serves to provide a balanced appearance. It will further be appreciated that the constituent parts of the articles cohere and form an essentially unitary structure, although the several individual parts may still be identified in the finished product.

The term rubber has been used in a generic sense to include not only natural Hevea rubber but also all analogous natural and synthetic rubbers and rubber-like materials.

While the invention has been described in considerable detail in connection with the menu-- facture of blood pressure bags, the principles herein set out obviously may be applied with advantage in the manufacture of numerous other articles. It will likewise be understood that many modifications and variations in details of the procedure and materials described may be efiected without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. The method of making a blood pressure bag or similar article which comprises providing a principal form having a flat rectangular portion and a stern projecting outwardly from an edge thereof, producing, by deposition from a liquid rubber composition, a unitary tube assembly including a tubular member terminating in a flaring reinforcing element continuous therewith,

mounting the tube assembly on the principal form with the tubular member on the stem and the flaring-reinforcing element embracing the flat'portion of the principal form, coating the 2,313,702 assembly with rubber, slitting the rubber coating at a point removed from the tube assembly, removing the form through the slit, applying rubber adhesive to the cut edges at the slit, abutting the edges, and coating the region about the slit with rubber.

2.,The method of making a blood pressure bag or similar article which comprises providing a principal form having a flat rectangular portion and a stem projecting outwardly from an edge thereof, producing, by deposition from a liquid rubber composition, a unitary tube assembly including a tubular member terminating in a flaring reinforcing element continuous therewith, mounting the tube assembly on the principal form with the tubular member on the stem and the flaring reinforcing element embracing the flat portion of the principal form, coating the assembly with rubber, slitting the rubber coating at a point removed from the tube assembly, removing the form through the slit, and sealing the slit.

3. The method of making a hollow rubber article having a communicating tube extending therefrom which comprises providing a principal form having a flat rectangular portion and a stem projecting outwardly from an edge thereof, producing, by deposition from a liquid rubber composition, a unitary tube assembly including a tubular member terminating in a flaring reinforcing element continuous therewith, mounting the tube assembly on the principalform with the tubular member on the stem and the flaring reinforcing element embracing the flat portion of the principal form, coating the assembly with rubber, and removing the form from within the article.

' 4. The method of making a hollow rubber article having a communicating tube extending therefrom which comprises providing a form having a main portion shaped to form the hollow article proper and a stem extending outwardly therefrom, producing a unitary tube assembly including a tubular member terminating in a flaring reinforcing element continuous therewith, mounting the tube assembly on the principal form with the tubular member on the stem and the flaring reinforcing element engaging the main portion of the form, coating the assembly with rubber, and removing the form from within the article.

5. The method of making a hollow rubber article having a communicating tube extending therefrom which comprises providing a form having a main portion shaped to form the hollow article proper and a stem extending outwardly therefrom, producing a unitary tube assembly including a tubular member terminating in a flaring reinforcing element continuous therewith, mounting the tube assembly on the form with the tubular member on the stem and the flaring reinforcing element engaging the main portion of the form, temporarily adhering the reinforcing element to the form, coating the assembly with rubber, and removing the form from within the article.

6. The method of making a hollow rubber article having a communicating tube extending therefrom, which comprises producing a tube assembly of rubber material comprising a tubular member and a flaring reinforcing element continuous therewith, and depositing rubber material from a liquid rubber composition to produce a hollow body in part in contiguous relation with the flaring reinforcing element and thereby to associate the tube assembly with the hollow body.

, GEORGE L. WINDER.

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