GB2089274A - Moulds for rotational casting - Google Patents

Abstract

A mould 1,2A used for manufacturing inflatable articles by known rotational moulding techniques is provided with means such that articles produced therefrom are permissive of being used:- (a) tethered to an object such for example as a rock, a peg hammered into the ground, or a groyne, (b) as a recreational device ridden by a human being sitting astride, (c) without tether attached, as a conventional ball. Said means are pegs or pins 4A, 4B of suitable dimensions fitted in permanent or removable fashion to the interior surface of the mould. Onto said pegs are pushed the ends of a tube (not shown) of appropriate material and dimensions before commencing the moulding operation for providing a permanent internally integral channel or passageway in the moulded article permissive of threading any suitable tether or handle. <IMAGE>

Description

SPECIFICATION Improvements in or relating to moulds and articles manufactured therefrom This invention is concerned with improvements in or relating to moulds and articles manufactured therefrom.

It is known to make hollow inflatable articles by rotational moulding techniques.

The moulds used may be of any dimensions and are hollow and normally substantially circular in cross-section having an interior shape which is complementary to the external shape of the inflated article required.

It is one of the various objects of the present invention to provide an improved mould for producing an inflatable hollow article of plastic material by rotational moulding whereby such article is provided with means internal and integral therewith which are or is permissive of the article being (a) tethered to an object such for example as a rock, a peg hammered into the ground or a groyne, (b) used as a recreational device to be ridden by a human being sitting astride such article.

Said means in the embodiment of the mould comprises projecting pins, pegs, stems or rods of suitable length, diameter and number fitted in either a permanent or removable fashion either to the first upper portion of the mould, or the second lower portion of the mould, or one or more of such pins, pegs, stems or rods in each of the aforesaid first and second body portions of the mould.

When used for manufacturing articles from the mould, and a measured quantity of thermo plastic material in powder or plastisol form is charged into the mould, a tube or tubes of any suitable plastic, metal or other material; length and diameter, is or are applied to the pins, pegs, stems or rods by pushing or pressing each end of the tube onto said pins/pegs thereby joining them together within the mould. The tube so fitted becomes an integral part of the moulded article and thereby provides an internal channel or passageway for the subsequent threading of a rope, cord, wire or handle, flexible or rigid, permissive of the article being tethered and or used as a recreational device capable of being ridden by a human being sitting astride such article.

Hereinafter described to illustrate the invention by way of example are photographic illustrations of the mould, Figure Nos. 1,2,3,4, and drawings of the article produced from the said mould, Figure Nos.

5,6,7,8,9,10.

The illustrative mould comprises a first body portion and a second body portion made of aluminium or any other suitable metal or alloy. Each body portion comprises a substantially hemispherically shaped portion with angular connecting rims permitting the two body portions to be aligned to provide a smooth continuous mould surface when the two body portions are clamped together in accordance with rotational moulding practice.

A hollow pipe extends through the wall of one or other of the two body portions into the interior of the mould, providing communication between the mould interior and atmosphere to relieve pressure within the mould when it is heated in carrying out a rotational moulding operation.

There now follows a detailed description to be read with the photographic illustrations and drawings accompanying the "REQUEST FOR THE GRANT OF A PATENT" (Patents Form No.1/77) concerned with the improvement in or relating to moulds and to articles manufactured therefrom, i.e. inflatable articles formed by rotational moulding using the illustrative mould. It is to be clearly understood that the illustrative mould and the illustrative article have each been selected for description by way of example and not by way of limitation of the invention.

In the photographic illustrations: Figure 1 depicts the interior of the first upper body portion of the mould, made for example in aluminium 1 and the interior of the second lower body portion made for example in aluminium 2A showing the hollow pipe extension to relieve the internal pressure within the mould 3, the fitted projecting pins, pegs, stems or rods 4A and 4B onto which the ends of the tubing are pushed or pressed on before the moulding operation begins, and as illustrated by the cutaway section of that part of the article inside out, showing the tubing after the moulding operation 5.

Figure 2 depicts the interior of the first upper body portion of the mould 1, the exterior of the second lower portion of the mould 2B, and the cutaway section of that part of the article inside out, showing the tubing after the moulding operation 5 as fitted to the pins/pegs 4A and 4B.

It is understood that the terms "first", "second", "upper", and "lower" herein used for the purpose of explanation do not necessarily indicate the positions of the various parts of the illustrative mould when the mould is used. It is further clearly understood that the novelty of the invention illustratively described by way of example, is not confined to any specific design and or shape of mould and or material from which the mould is made and or measurements of the mould whatsoever.

Figure 3 depicts the exterior of the first upper body portion of the mould 1A and the exterior of the second lower body portion of the mould aligned and assembled together 2B by way of example; and a cutaway section of that part of the article inside out, showing the tubing after the moulding operation 5 with tubing ends pushed into position on the pins/pegs 4A and 4B inside the mould before the moulding operation is begun.

Figure 4 depicts the first upper body portion of the mould 1A and the second lower body portion of the mould 2B aligned and assembled together in one of a variety of suitable frames 6 for securing the mould to the carrier of a rotational moulding machine after the mould has been charged with a measured quantity of thermo plastic material in powder or plastisol form, and a tube of desired material and dimensions has been fitted to the pins pegs, stems or rods on the inside surface of the body section(s) 4A and 4B, said tube subsequently to become the channel or passageway integrally moulded within the finished article through which will be threaded a flexible or rigid rope, cord, wire, or handle permissive of the article being (a) tethered, and or (b) used as a recreational device to be ridden by a human being sitting astride the article.

In the drawings: Figure 5 illustrates a top elevation of an article moulded from the mould Figure Nos. 1,2,3,4 and indicates the two open ends of the internally integral channel or passageway 5 after moulding. Also indicated is the inflation and deflation orifice 7 into which, if desired, any suitable valve may be inserted.

It is to be clearly understood that the position of the inflation hole which is formed by placing a sleeve of plastic or other suitable material over the hollow pipe 3 before setting up the mould, is shown only by way of example and not by way of limitation.

Figure 6 is a drawing of the side view of the article east to west, and west to east a top elevation of which is depicted in Figure 5. The open ends of the channel or passageway 5, and the inflation/deflation orifice 7 are flush with the outer surface of the article.

Figure 7 is a side view of the article depicted in the Figures 5 and 6 showing one end of the channel or passageway 5 as therein described. The view from the opposite side corresponds.

Figure 8 is a section drawing of the article east to west or west to east i.e. other side opposite corresponds, showing a flexible tether or handle 8 threaded through the channel or passageway 5 and the ends joined together by means of a knot which is shown only by way of example and not by way of limitation, also the two free ends of a threaded handle may be left unjoined, if desired, and whether or not the article is used as a vehicle to be ridden by a human being.

Figure 9 is a section drawing of the moulded article as depicted in Figure 8 and showing an example of a rigid tether or handle 9 applied to the moulded article.

Figure 10 illustrates a side view of the moulded article seen and described in Figure 8.

Claims (8)

1. A mould for producing an inflatable hollow article of plastic material by rotational moulding,the mould comprising a first body portion and a second body portion being such that when the body portions are clamped together the interior surfaces of same provide a smooth continuous surface.

2. A mould according to claim 1 to which has been added internally permanent or detachable pins, pegs, stems, or rods of suitable dimensions spaced apart, thereby forming a means of positioning within the mould a piece of tube or tubing, manufactured from plastic or any other suitable material, and of suitable dimensions, to form an internally integral channel or passageway for a flexible or rigid tether and or handle to be threaded, if desired, to the finished moulded article.

3. A mould according to claims 1 and 2 wherein the mould interior is open to atmosphere.

4. A mould according to claim 3 wherein a hollow tubular element extends into the mould to provide communication between the mould interior and the atmosphere.

5. A mould according to any one of the preceding claims wherein the first and second body portions have annular rim portions adapted to be pressed together when the first and second body portions are clamped together.

6. A mould according to claim 1 substantially as hereinbefore described with reference to Figure Nos.

1, 2, 3, and 4 of the accompanying photographic illustrations.

7. An article produced from the mould described according to the aforesaid claims such as is provided with an internally integral channel or passageway permissive of housing a tether or handle attachment hereinbefore described with reference to Figure Nos.

5, 6, 7, 8, 9, and 10 of the accompanying drawings.

8. An article according to claim 7 which, if produced in the shape of a ball of any diameter or circumference, and used either with the novel tether or handle attachment removed or not attached to the article, the said article is capable of being used as a conventional ball, i.e. football, playball, beachball, volleyball, netball, waterpolo ball, or ball(s) similar to the aforesaid used for any other purpose.