US3204959A - Hollow inflatable article - Google Patents

Description

Sept. 7, 19 65 B. F. NICHOLLS HOLLOW INFLATABLE ARTICLE 2 Sheets-Sheet 1 Filed March 16, 1961 p 7, 1965 B- F. NICHOLLS 3,204,959

HOLLOW INFLATABLE ARTICLE Filed March 16. 1961 ,2. Sheets-Sheet 2 FIG? INVENTOR. B yan F N icholls Attorney United States Patent 3,204,959 HOLLOW INFLATABLE ARTICLE Bryan F. Nicholls, Northampton, England, assignor to The Mettoy Company Limited, London, England Filed Mar. 16, 1961, Ser. No. 96,252

11 Claims. (Cl. 27358) This invention relates to inflatable playballs or like articles.

Heretofore, in the manufacture of hollow inflatable balls or like articles by rotational casting methods from synthetic resin materials, such as polyvinyl chloride, 1t has been the generally accepted practice to incorporate integral, resilient housings in the same during rotational casting of the article and to insert rigid valve units or airsealing plugs within said valve housings after removal of the otherwise completed articles from the molds. Valve units or plugs provided for this purpose, however, were difficult to insert through apertures in the valve housings or were not sufficiently bonded to the housing to prevent loss of inflation air.

One object of the invention is to provide an improved hollow inflatable article of the character described having integrally incorporated in the wall thereof a durable and efficient, self-sealing inflation valve unit.

Another object of the invention is to provide an inflatable ball or like arL'cle in which is eliminated the usual necessity for providing a bulky valve housing which adversely affects the rolling and bouncing qualities of the article in use.

This application corresponds to Bryan F. Nicholls application No. 1,5 66/ 60, filed in Great Britain on April 1, 1960.

These and other objects of the invention will be manifest from the following brief description and the accompanying drawings.

Of the accompanying drawings:

FIGURE 1 is a front elevation, partly broken away and in section, of a playball having incorporated therein one embodiment of the improved inflation valve means of the invention, as produced by the method of the invention.

FIGURE 2 is a greatly enlarged vertical cross-section through the ball inflation valve as viewed substantially on the line 2-2 of FIGURE 1.

FIGURE 3 is a further enlarged cross-section, taken substantially on the line 3-3 of FIGURE 2.

FIGURE 4 is a fragmentary cross-section, on a reduced scale corresponding to that of FIGURE 1, illustrating a sectional cavity mold, in closed condition, ready for an article-forming step in accordance with the method of the invention.

FIGURE 5 is a cross-section corresponding to FIG- URE 2, illustrating a modified form of valve structure in a ball.

FIGURE 6 is a fragmentary cross-section through an article-forming mold, corresponding in part to FIGURE 4, and illustrating provision of a modified form of valve unit for incorporation in an inflatable ball.

FIGURE 7 is a transverse cross-section, greatly enlarged, of the valve unit substantially in the relationship shown in FIGURE 6, but after removal of the finished article from the mold.

FIGURE 8 is a horizontal cross-section taken substantially on the line 88 of FIGURE 7, and on the same scale.

FIGURE 9 is a fragmentary cross-section corresponding to FIGURE 6, and on the same scale, illustrating another modified form of valve unit for incorporation in an article to be formed in the mold.

FIGURE 10 is an enlarged side elevation of the valve unit shown in FIGURE 9, prior to positioning the same in the mold.

FIGURE 11 is an enlarged fragmentary cross-section corresponding to FIGURE 9, but illustrating a portion of the fully formed article produced in the mold, with the valve unit of FIGURES 9 and 10 incorporated in the article.

FIGURE 12 is a view corresponding to FIGURE 7, illustrating the fully formed article with the valve unit of FIGURE 10 incorporated therein, after removal of the article from the mold.

FIGURE 13 is a further enlarged horizontal crosssection, taken substantially on the line 1313 of FIG- URE 12.

FIGURE 14 is a horizontal cross section, taken substantially on the lines 14-14 of FIGURE 12.

Referring to FIGURES 1 to 3 of the drawings, the numeral 10 designates .a hollow inflatable playball formed of elastic material, such as polyvinyl chloride, and having an inflation valve unit 12 permanently affixed to a relatively thin wall of the same to project freely inwardly. As best shown in FIGURES 2 and 3, the valve unit may include a rigid body or stem 13 of metal, or hard plastic material such as rigid polyvinyl chloride, the stem being embedded in a casing 11a of plastic material which is an integral extension of the wall 11. Casing 11a extends from a relatively thickwalled portion 11b adjacent wall 11 to a thin rounded end portion 110.

Formed in the wall 11 of the article may be a cylindrical passage 14 communicating with an elongated passage 15 in the stem 13, for inward reception of a suitable inflation tool T, which may have a part adapted to be screwed into a threaded outer end portion 16 in passage 15 (see FIGURE 2). The passage 15 has a reduced inward extension 17 at the inner end of which is a small aperture 18 extending to the longitudinally centered portion of an angular groove 19, defining a smooth cylindrical surface 20. Yieldingly expanded onto said cylindrical surface 26 may be a cylindrical tube or sleeve 21 of air-impervious rubber or rubber-like elastic material. The tube 21 may extend substantially to the full length of the groove 19, and the thickness of the tube is equal to or less than the depth of the groove. Accordingly, the resilient tube 21 is adapted normally to seal the opening 18 against outward escape of inflation air from the article, through the stern passage 15.

For inflating the ball 10, inflation air from a suitable source is forced, by means of the inflation tool referred to above, into the passage 15, through the aperture 18, and into the space between the tube and sealing surface 20, whereby the tube is yieldingly expanded to allow passage of inflation air past the inner end of the tube and through a slit 22 in casing portion lie to the interior of the ball (see FIGURES 1 and 2). Tube 21 is of substantial length, as shown in FIGURE 2, in relation to the size of aperture 18, to provide a maximum area of sealing surface on the cylindrical surface 20, and it may be slightly shorter than the length of the groove 19, to obviate any tendency of the tube to buckle and thereby minimize the air-sealing contact with the surface 20.

In use of the improved valve device, as best shown in FIGURES 1 and 2, inflation air from a suitable source is supplied to the interior of the ball 10, as by means of the tool T threaded into the threaded portion 16 of the stem 13, or by insertion of a suitable inflation needle into the stem passage 15 in known manner. In either instance, inflation air is forced through the aperture 18 in the stem 13 to expand the elastic tll'be 21, as previously described, to inflate the ball 10 as required. When the 'ball is fully inflated the inflation tool T is withdrawn, in which event in the internal pressure within the article will 3 hold the rubber sleeve tightly contracted in air-sealing relation against the smooth cylindrical surface 20, and thereby to prevent return of inflation air outwardly through the passage 15.

One method for producing the article illustrated in FIGURES 1 to 3 will be best described in connection with FIGURE 4, wherein is illustrated a sectional cavity mold 24, having a metal pin secured to the wall thereof to project radially inwardly from an article-forming cavity surface 26 thereof. While the mold is open, an operator mounts a rigid valve stem 13, with rubber tube 21 expanded thereon, on the pin 25 (see FIGURE 4) to have the outer end of the stem in slightly spaced relation to the inner mold surface 26.

After placing a predetermined quantity of heat-flowable resin material, such as polyvinyl chloride plastisol, in the bottom part of the mold 24, the operator closes the mold and causes the same to be rotated about a plurality of axes within a heating chamber (not shown) for a predetermined period sutficient to form the plastisol into a ball 10 of uniform wall thickness on the article-forming mold surface 26. The rotational casting process is practiced under controlled conditions, first to form the wall or layer 11 of gelled plastisol, and then to fuse the same.

During the article-forming cycle, the fluid plastisol forming the wall 11 will also flow and form the casing 110 about the stem 13, including serrated or toothed portions 27 thereof, the rubber elastic tube 21, and the rounded end 28 of the stem. Due to unequal distribution of heat between the mold wall and the outer end of stem 13 the deposited mate-rial on the stem will be thicker near the wall of the mold, as indicated at 11b and relatively thin at the rounded outer end 110, but in any event, uponsubsequent cooling of the article contraction of the casing 11a about the stem is effective in the finished article to retain the stem firmly imbedded in air-sealing relation therein. The portions of the casing 11a surrounding rubber tube 21 do not necessarily adhere to the latter. The elastic casing portion 110 at the rounded end 28 of the stem, inwardly of the tube 21, being relatively thin, is expanded upon first application of inflation air past the inner end of the tube, to rupture the casing 11a and thereby form the air-inlet slit 22 therein.

Accordingly, because the stem is integrally bonded and embedded in a casing 11a of polyvinyl chloride material, which is integral with the wall 11 of the ball, the completed article may be inflated immediately upon removal of the same from the mold 10, whereas in known previous methods used for making polyvinyl chloride articles the ball could not be inflated until after removal of the same from the mold and after a valve had been inserted in a valve housing provided for that purpose. In the present structure the elastic nature of the casing 11a covering tube 21 is eifective to supplement the air-sealing contraction of the tube on stem portion 20.

Referring to FIGURE 5, there is illustrated a ball 10a made by the method described, but having a modified form of valve unit 12a incorporated therein. This valve unit may include an elongated tubular stem 13:: which is closed at its inner end, as indicated at 29, and has a small outlet aperture 30 through the wall thereof at a point centrally of an elongated, rubber-like elastic sleeve or tube 31, yieldingly expanded onto stem 13a. The stem may be of a material having a strong bonding affinity for the vinyl plastisol used in the method described above, so that during the article-forming process fluid plastisol will form a casing 11d around the valve unit 12a, as before, the plastisol, however, being integrally bonded to the portions of the stem 13a exposed beyond the opposite ends of the rubber sleeve. A suitable material for the rigid stem 130 may be unplasticized polyvinyl chloride, molded, or extruded, or otherwise produced in known manner. The stem 13a is adapted to be mounted on a pin 25 afiixed in the mold, substantially in the manner and for the purposes described in connection with FIG- URE 4.

In FIGURES 6 to 8, there is illustrated a modified form of valve unit 33 provided in a playball 34, said valve unit including a rigid, solid plastic tem 35, adapted to be molded with a straight inflation passage 36 therein in a way which eliminates the necessity for provision of a separately drilled air outlet aperture. For this purpose the stem maybe of substantial length and of circular cross-section, and may be molded from rigid polyvinyl chloride to have angularly disposed straight outer and inner end portions 37 and 38, respectively, of substantially uniform cross-section, including a smoothly rounded or curved juncture 39 between the same.

A straight, cylindrical passage or bore 36 extend from the outer end of the stem, axially through the straight outer portion 37, to a point on the smooth surface of the inner straight portion 38, inwardly beyond said curved juncture 39. An air-impervious tube 41 of rubber-like elastic material is yieldingly expanded onto the stem to grip the same in air-sealing relation, including said curved juncture 39, and adapted to seal the inner end of the passage 36 against outward escape of inflation air from the article 34.

The valve unit 33 is adapted to be applied to a pin 43 aifixed in the mold, as shown in FIGURE 6, and the ball or like article is formed in the mold as before. Accordingly, a casing 44, which is an integral extension of the wall of the ball 34, forms about the valve unit 33, as shown in FIGURES 7 and 8, and in the manner substantially as described above in connection with FIG- URE 5. As the casing is relatively thin at the inner end of rubber sleeve 39, the initial application of inflation air to the ball is effective to provide a slit 45 in the casing 44 to permit free passage of inflation air to the interior of the ball, as previously described.

Referring to FIGURES 9 to 14, there is illustrated still another form of the invention, in which the rotational casting method of forming a playball is utilized .to form essential parts of a self-sealing valve unit 47 which is integrally connected with the wall of a ball 48.

For this purpose a stem compriisng a straight length 49 of split tubing, cut from a continuous length of rigid extruded polyvinyl chloride stock, has a shorter length 50 of air-impervious, rubber-like elastic material yieldingly expanded onto the same, as shown in FIGURE 10. The valve stem 49 with the elastic tube 50 thereon, is mounted on a pin 52 affixed in a ball mold 53, substantially in the manner of the valve units best shown in FIGURE 6, but with the mounting pin 52 extending to a point slightly inwardly of the midpoint of the split stem 49. As described in connection with FIGURES 6 to 8, rotational casting methods are used to form the wall 54 of the playball 48 and to form a sheath or casing 55 of the casting material about the valve stem 49 and tube 50. In additlon to formation of the casing 55, however, the p'lastisol flows inwardly of 'both ends of the slit 56 in the stem 49, and also plugs the inner end of the split stem to the end of the mounting pin 52 (see FIGURES 10 and 11). Due to the inevitable presence of trapped air, however, a central portion of the slit remains void of the flowing plastisol, and the result of the process is provision of a solid stem 49a which is non-adhered to the elastic tube 50 and has a passage 57 from the outer end thereof to the void or formed aperture 58 centrally of the rubber tube 50, as best shown in FIGURES 12 to 14.

As before, upon initial inflation of the finished ball structure of FIGURES 12 to 14, inflation air passes from passage 57, through outlet aperture 58, yieldingly to expand elastic tube 50, and thereby to provide a permanent rupture or slit 59 at the thin inner end of the casing 55.

The method described in connection with FIGURES 9 to 14 eliminates the usual necessity for providing and mounting a precured resilient vinyl housing or insert in mold, mounting a self-sealing valve unit in such housing in the fully formed article. The method also makes it possible to use precut lengths of continuous material for the valve assembly, with consequent savings in materials and labor.

The several forms of valve units referred to may be produced in hollow polyvinyl chloride articles by known methods other than as described above, including slush molding methods.

Other modifications of the invention may be resorted to without departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

1. A hollow inflatable article having a wall of flexible elastic material and a self-sealing inflation valve therein; said valve including a relatively rigid elongated stem having at least the outer end thereof anchored Within said wall, and the stem having an inner smooth-surfaced peripheral portion of substantial extent over which is yieldingly expanded an elongated sleeve of elastic tubing to be in air-sealing relation thereto; said stem having an inflation passage extending therethrough for connecting the exterior of the wall with outlet means at the inner end of the passage and intermediate the ends of said sleeve, whereby the outlet means is normally airsealed by the sleeve; application of inflation air within the stem passage thereby being adapted yieldingly to expand said sleeve for passage of inflation air past the inner end of the sleeve to inflate said article wall; said article wall having structural characteristics resulting from rotational casting of thermo-plastic resin material in a closed mold While in heat-softened condition and by which integral inward extensions of the material from said wall Will upon cooling have formed an elastic casing of inwardly diminishing thickness about said stem and sleeve; said elastic casing thereby anchoringly attaching the stem to said Wall and yieldingly embracing the sleeve in said air-sealing relationship.

2. An inflatable article as in claim 1, said peripheral portion of the stem being cylindrical and said sleeve being of smaller internal diameter than said peripheral portion.

3. An inflatable article as set forth in claim 2, said stem having at least portions thereof integrally bonded to said elastic material of the article.

4. An inflatable article as set forth in claim 3, said stem including outer and inner angularly disposed cylindrical portions and said tube being disposed on the stem to have the juncture of said outer and inner stem portions intermediate opposite ends of the tube, said inflation passage being a straight bore through said outer stern portion and terminating at said outlet means on the cylindrical surface of said inner stem portion at a point intermediate said opposite ends of the tube.

5. An inflatable article as set forth in claim 1, said stem including outer and inner angularly disposed cylindrical portions and said tube being disposed on the stem to have the juncture of said outer and inner stern portions intermediate opposite ends of the tube, said inflation passage being a straight bore through said outer stem portion and terminating at said outlet means on the cylindrical surface of said inner stem portion at a point intermediate said opposite ends of the tube.

6. An inflatable article as set forth in claim 5, said flexible elastic material being polyvinyl chloride.

7. An inflatable article as set forth in claim 1, said flexible elastic material being polyvinyl chloride.

8. An inflatable article as set forth in claim 1, said stem being a cylindrical tubular member having a split portion extending between the opposite ends thereof and said elastic sleeve being yieldingly expanded onto said member intermediate said opposite ends thereof, the material of said wall and the casing formed on the stem also being extended to close the inner end of the inflation passage against passage of inflation air and likewise by such extension to close said split inwardly from said opposite ends of the stem except for a void in the split constituting said outlet means communicating with said inflation passage means.

9. An inflatable article as set forth in claim 8, said stem being of material having a bonding aflinity for said elastic material of the article.

10. An inflatable article as set forth in claim 9, said elastic material being polyvinyl chloride.

11. An inflatable article as set forth in claim 10, said stem being rigid polyvinyl chloride.

References Cited by the Examiner UNITED STATES PATENTS 1,326,445 12/19 Fewlars 46-90 2,233,096 2/41 Goldsmith 137223 2,477,899 8/49 Rempel 18-583 2,629,134 2/53 Molitor 1858.3 2,731,060 1/56 Rowe.

2,760,775 8/56 Tipton 273-58 2,935,320 5/60 Chupa 273-58 RICHARD C. PINKHAM, Primary Examiner. DELBERT B. LOWE, LOUIS R. PRINCE, Examiners.

Claims (1)

1. A HOLLOW INFLATABLE ARTICLE HAVING A WALL OF FLEXIBLE ELASTIC MATERIAL AND A SELF-SEALING INFLATION VALVE THEREIN; SAID VALVE INCLUDING A RELATIVELY RIGID ELONGATED STEM HAVING AT LEAST THE OUTER END THEREOF ANCHORED WITHIN SAID WALL, AND THE STEM HAVING AN INNER SMOOTH-SURFACE PERIPHERAL PORTION OF SUBSTANTIAL EXTENT OVER WHICH IS YIELDINGLY EXPANDED AN ELONGATED SLEEVE OF ELASTIC TUBING TO BE IN AIR-SEALING RELATION THERETO; SAID STEM HAVING AN INFLATION PASSAGE EXTENDING THERETHROUGH FOR CONNECTING THE EXTERIOR OF THE WALL WITH OUTLET MEANS AT THE INNER END OF THE PASSAGE AND INTERMEDIATE THE ENDS OF SAID SLEEVE, WHEREBY THE OUTLET MEANS IS NORMALLY AIRSEALED BY THE SLEEEVE; APPLICATION OF INFLATION AIR WITHIN THE STEM PASSAGE THEREBY BEING ADAPTED YIELDINGLY TO EXPAND SAID SLEEVE FOR PASSAGE OF INFLATION AIR PAST THE INNER END OF THE SLEEVE TO INFLATE SAID ARTICLE WALL; SAID ARTICLE WALL HAVING STRUCTURAL CHARACTERISTICS RESULTING FROM ROTATIONAL CASTING OF THERMO-PLASTIC RESIN MATERIAL IN A CLOSED MOLD WHILE IN HEAT-SOFTENED CONDITION AND BY WHICH INTEGRAL INWARD EXTENSIONS OF THE MATERIAL FROM SAID WALL WILL UPON COOLING HAVE FORMED AN ELASTIC CASING OF INWARDLY DIMINISHING THICKNESS ABOUT SAID STEM AND SLEEVE; SAID ELASTIC CASING THEREBY ANCHORING ATTACHING THE STEM TO SAID WALL AND YIELDINGLY EMBRACING THE SLEEVE IN SAID AIR-SEALING RELATIONSHIP.

Images