US2518326A

US2518326A - Inflatable form for dipped rubber articles

Info

Publication number: US2518326A
Application number: US752108A
Authority: US
Inventors: Ingram George
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-06-26
Filing date: 1947-06-03
Publication date: 1950-08-08
Anticipated expiration: 1967-08-08

Description

Aug. 8, 1950 Filed June 5, 1947 G. INGRAM INFLATABLE FORM FOR DIPPED RUBBER ARTICLES 2 Shee'ts-Sheet 1 g- 8, 1950 s. INGRAM INFLATABLE FORM 5'01: DIPPED RUBBER ARTICLES 2 Sheets-Sheet 2 File d June :5,- 194'! Q QBE v r //v va- .zvroe 650E615 N M- Patented Aug. 8, 1950 STATES PATENT OFFICE.

PNFLATABLE FORM FOR Dir-pron RUBBER ARTICLES? George Ingram, London, England Application .Fune 3,1947, Serial No; 7521 08 In Great Britain June-26,1942

Sectionl, Public Law 690, August 8,1946 Patent expires June 26; I962 3 Glaims. l

This inventiorrrelates to" the manufacture of rubber articlesmade by dipping a former into toallow the former toberemoved from the article or vice: versa, with the result that production is not-as easy or as rapidas' might be'desire'd'. Also, owing" to the Ii'IrI-ited extent to which the neck can stretch without risk of damage, it is impossibleby" present methods to manufacture an article having a body portion of' more than a predetermined dimension with respect to the neck. The present invention has in view to overcome thi's' last di ifrcul ty so as topermit an article to be manufactured having, a body portion of larger dimensions relative to the neck size. The invention further aimsat expediting the manufacture of articles wherein thebody and neck dimensions accord with present practice;

The invention consists in the provision of a former foruse in the manufacture of dipped rubber' articles, and which comprises an envelope made of substantially imperviousfiexible sheet material and having a neck, resilient bracing means,- contained within said envelope; and a rigid manipulating stem passing" through the n'ecloof the envelope and into the interior thereof, the bracing means being adapted to maintain the envelope in a taut, distended or expanded condition; and being adapted by its resiliency to allow the envelope to collapse to the extent necessary for withdrawal of said envelope through the neck of "the formed article.

i bracin meanscan take varying forms and in one embodiment of the invention consists of. resilient arms radiating from the manipulating stem and forming components of a framework, said. arms being" urged by their inherent springiness to'mainta'in the envelope in a taut, distended on-expanded condition. In another embodiment thesaidabracmg.means'eonsists of tubular flexible arms radiating from the stem and arranged to form contiriua-tions of the bore extending through the stem; said. arms havineclosed outer ends and being adapted to be inflated by way of the stem" and to be thereby stifien'ed to-serve asthe brac ing means: Inanother formof the invention the bracing means consist of ribs formed integrally with the envelope on the interior" thereof.

a further embodiment oftheinvention the former.- comprises an inflatable envelopeha-vi-ng a neck,- a-

rigidtubular manipulating stem passing through said neck and extending across the envelope to a point oppositesaid neck, and one or more open-- ings formed in said stem to enable the envelope to be inflated and deflated by way of the stem.

In the accompanying drawings,

Figure 1 is a vertical section of a dipping former constructed according to one embodiment of theinvention,

Figure 2 is a cross-section on:line':ra:in Figure' 1 Figure 3 isa sectional detail view showing the manner in which bracing arms are attached to the stem ofthe former,

Figure i is a perspective-view showing a means for engaging the outer ends of said bracingarnis to constrain same to takeup required forms;

Figure 5 is a sectional view of a former em-- bodying inflatable bracing arm's;

Figure 6 is a diagrammatic View showing the manner of arranging and using an inflatable former inaccordance with the invention, and

Figure 7 isan elevation showing a form of article which can be conveniently made by the use of an inflatable former provided in accordance withthe invention.

Referring firstly to Figures 1, .2 and 3, there" is provided an envelope It made of flexible sheet material such as oilskin, rubber, waxed paper or textile fabric which has been coated or impregnated so as to be substantially impervious, or any sheet material having similar characteristics, said envelope having a tubular neck H. Prefer ably said envelope has a serrated inner surface. rigid tubular manipulating stem l2 which passes-through the said neck I I has screwed upon its inner end a tubular T-piece I3 Each of'the arms It of said T-piece is provided internally with a tapering resilient throat piece l5 which may be made of rubber. Strips or rods [6 made of whalebo'ne, springy metal or other resilient material are-adapted to be inserted into the respective throat pieces [5, so that each of said strips or rods is thus held by one end to the stem i2, the said throat piece effecting a firm grip on the saidstrip or" rod and preventing accidental detachment thereof. The said strips or rods I6" constitute arms of a framework for bracing envelope so as to maintain same in a taut, distended or expanded condition, said arms radiating from the stem and extending back towards the neck of the envelope. In the construction shown, the framework formed by said arms has the form of an interrupted hoop but may have any desired form and configuration. The serrated internal surface of the envelope assists in retaining the arms is in the throat pieces I5.

In Figure 1 the arms l6 have their upper ends free, but if desired means may be provided on the stem ii for engaging the said upper ends of said arms to constrain them to take up a particular contour. Figure 4 illustrates a device for this purpose consisting of a collar I! adjustably mounted on the stem I2 and having notches it into which the upper ends of the arms Hi can be engaged.

In the portion of the tubular stem [2 which is situated within the envelope Ill there are formed aplurality of holes is. Said holes is permit the passage of air into and out of the envelope when same is collapsing and when takin up a taut or expanded condition, or said holes may be utilised for inflation of the envelope by air passedunder pressure through a valve-fitted nozzle 20 and down the stem l2.

In the example shown (see especially Figure 2) the bracing arms [6 and the stem 12 are disposed all in the same plane so that the envelope normally has a substantially flat condition but is adapted to be expanded under air pressure so as to take up a spherical or other required form as shown by'dotted lines.

In the modification shown in Figure 5, the bracing arms i6 consist of tubes made of flexible material such as rubber and having closed outer ends, said tubes being suitably secured to a T-piece [3 provided on the lower end of the stem l2 and being so arranged that they form branch continuations of the bore therein. In this case the stem l2 will not be provided with holes for air escape from or for inflation of the envelope iii as the stem bore will be utilised for setting up air pressure in the tubular arms [6. By such air pressure the said arms 66 will be stifiened toserve as a bracing means, whereas said arms IS- will be relatively limp when deflated. As a modification of this arrangement the stem 52 may be provided with an inner tube for inflation of the tubular arms [6, the stem proper being formed with holes for air escape from or inflation oi the envelope as explained with reference to Figure 1.

As an alternative to the construction shown in Figures 1 and 3, the bracing framework may consist of a single length of strip or rod passed through the head of a T-piece such as l3 and centrall anchored therein so that the respective end portions of said strip or rod constitute the arms 16.

InYeach of the constructions above described the neck ii of the envelope can be made in one piece or may be formed from two identical parts seamed together.

In'the construction shown in Figures 1 to 3, the bracing arms is exert themselves to maintain the former envelope l0 distended in the plane of said arms and in a flat, natural condition. Said arms l6 however can be pressed towards the stem 12 and be thus distorted to approximate straight forms in which they take up positions nested against the stem when it is desired to collapse the former. In assembling the former for use, and assumin that he arm l6 and T-piece 13 are alone already contained in the envelope If], the tubular stem I2 is passed through the envelope neck ll, said neck being stretched sufficiently to permit of this. The inner end of the stem will reach a position close to the perimeter of the envelope, at a position directly opposite the envelope neck H. Said neck will contract on to the stem l2 to grip same tightly. The arms l6 are now fitted into the throat pieces 15 of the T-piece l3. These operations are performed by gripping the parts through the envelope. The former is now ready to be dipped into the solution.

Air escape permitted from the interior of the former by way of the holes E9 in the tubular stem l2, the bore in said stem and the valvefitted nozzle 20, allows for the release of any pressure which may be set up by deformation of the envelope on submersion into the dipping solution.

In the construction shown in Figure 5 the tubular arms I6 have a limp condition when deflated to permit of the former being easily and readily withdrawn through the neck of the formed article.

Although in the constructions above described the bracing framework comprises only a single hoop, it is to be understood that any desired number of hoops may be provided, arranged or adapted to be arranged in different planes. A framework composed of such hoops will give the former a bulbous, spherical or other threedimensional as compared with a two-dimensional form.

The manipulating stem l2 serves as a means for suspending the former from any desired dipping device; for instance, as shown in Figure 6, the said stem (and the stems of any additional iormers to be immersed simultaneously) may be attached to a board 2| adapted to be raised and lowered by suspension cords 22 to immerse the former into a dippin bath 23.

In a modification (not shown) the envelope is not provided with bracing means but is adapted to be inflated in order to bring it to the required shape and form. In this case the tubular manipulating stem l2 passes through the envelope neck as a tight fit and extends across to a point opposite said neck where it is provided with a suitable foot piece, and one or more openings are formed in the said stem to enable the en- Velope to be inflated and deflated by way of the bore through the stem. Thus inflation, apart from being used in a former having bracing means, can be utilised as a sole means for distending the envelope, especially in the manufacture of small articles.

If the former envelope [0 has air-retaining properties, then the method of use may include inflating said envelope either before, during or after immersion into the dipping solution, a supply duct 24 for compressed air being connected up to the nozzle 20 provided on the tubular stem (Figure 6). Such inflation serves in co-operation with the internal bracing means to distend the envelope, and if the envelope has elastic properties it may even expand same. Such inflation is particularly advantageous in the case where the manufactured article is required to have one or more protrusions, such as 25 shown in Figure '7, the former envelope then being immersed into the dipping solution in a deflated condition and being inflated whilst immersed, thereby making the protrusion (as well as the main body of the envelope) rigid. the inflated condition being maintained after removal from the dipping solution. This overcomes the objection that if the protrusion was rigid before immersion, same would resist submersion and might distort, with the possibility of introducing air bubbles into the solution.

It will be readily understood that collapse of the former which can be effected whatever its construction in accordance with the invention, enables the manufactured article to be easily removed from the former, even when the body of the former has a dimension relative to-a neck, considerably greater than the maximum dimension possible by existing methods of manufacture. If the manufactured article is required to have lateral protrusions then the collapse of the former will be of great advantage since a former having a rigid protrusion of substantial length could not be employed by present-day methods owing to the neck being unable to expand sufficiently for the protrusion to pass through. The invention is also especially advantageous in the manufacture of a balloon or other article having an eccentric shape or having a neck disposed laterally with respect tothe major axis of the article as in the example illustrated in Figure 7.

I claim:

1'. A former for use in the manufacture of dipped rubber articles having a neck, comprising an envelope made of substantially impervious flexible sheet material and also having a neck,

7 a tubular rigid stem passing through the neck of the envelope, tubular flexible arms communicating with and radiating from the lower end :1,

ing withdrawn through the neck of the formed article.

2. A former for use in the manufacture of dipped articles of rubber or rubber-like material, said former comprising an envelope of substantially impervious flexible sheet material having a neck, a tubular stem extending through the neck of said envelope into said envelope, and tubular flexible inflatable and deflatable arms connected to and in communication with said stem at their inner ends and having their outer ends closed and free, whereby they are adapted to be inflated and stiffened to brace said envelope and to maintain the same taut by fluid supplied to them through said stem and whereby when deflated they are adapted to permit ready collapse of said envelope for easy removal of the latter through the neck of an article formed about the same.

3. A former for use in the manufacture of dipped articles of rubber or rubber-like material, said former comprising an envelope of substantially impervous flexible material having a neck, a tubular stem extending into said envelope through said neck, and tubular flexible inflatable and deflatable arms disposed in said envelopeand connected to and in communication with said stem for inflation and deflation by fluid supplied to and exhausted from them through said stem, said arms when inflated being substantially stiff and serving to maintain said envelope taut and when deflated permitted ready collapse of said envelope for easy removal of the latter through the neck of an article formed about the same.

GEORGE INGRAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,881,005 Watkins Oct. 4, 1932 2,236,306 Bratring Mar. 25, 1941 2,310,362 Frissell Feb. 9, 1943

Claims

1. A FORMER FOR USE IN THE MANUFACTURE OF DIPPED RUBBER ARTICLES HAVING A NECK, COMPRISING AN ENVELOPE MADE OF SUBSTANTIALLY IMPERVIOUS FLEXIBLE SHEET MATERIAL AND ALSO HAVING A NECK, A TUBULAR RIGID STEM PASSING THROUGH THE NECK OF THE ENVELOPE, TUBULAR FLEXIBLE ARMS COMMUNICATING WITH AND RADIATING FROM THE LOWER END OF SAID STEM IN DIFFERENT DIRECTIONS AND ARRANGED TO FORM BRANCH CONTINUATIONS OF THE STEM BORE, SAID ARMS BEING CLOSED AT THEIR OUTER ENDS AND ADAPTED TO BE INFLATED BY WAY OF THE TUBULAR STEM AND TO BE THEREBY STIFFENED TO SERVE AS A BRACING MEANS FOR THE ENVELOPE TO MAINTAIN SAME IN A TAUT DISTENDED OR EXPANDED CONDITION AND BEING ADAPTED ON DEFLATION TO ALLOW THE ENVELOPE TO COLLAPSE READILY TO PERMIT OF SAID ENVELOPE BEING WITHDRAWN THROUGH THE NECK OF THE FORMED ARTICLE.