IL29082A - Core for the manufacture of hollow bodies from mouldable materials and process therefor - Google Patents

Description

for the manufacture of hollow bodies from materials and process therefor 2 The invention relates to inflatable cores for use in the manufacture of hollow receptacles for storing or transporting granular materials or the by especially by spray or injection moulding from synthetic a mixture of ester resin glass fiber By a known receptacles of this kind are made by spraying a mixture of synthetic resin and glass to a rotatable Such cores consist of a number of component parts which have to be assembled for and the core has to be dismantled and the parts to be withdrawn from the moulded body after the latter has For purpose the receptacles have to have manholes whose size corresponds to that of the component parts of the Such manholes require particularly strong lids and appropriate securing and tightening in impair the strength of the moulded The cores themselves are and complicated to manufacture and their use is unprofitable owing to the fact that they remain in the moulded receptacle during time during that remain unavailable so that manufacture requires a large number of expensive The invention has the object to decrease the costs of the to accelerate the manufacture of the receptacles and to enable the latter be made with smaller more advantageous 3 The invention consists in a core for the facture of hollow especially from mouldable comprising an inflatable bag of pliable foil in inflated assumes the intended shape of the inner space of the hollow body and which has at both ends apertures surrounded by rims in the inflated state of the become tightened hermetically on to a In a preferred embodiment of the invention a pliable tube extends coaxially through the bag into the rims of the apertures at both preferably beyond clamps or the like fastening means provided for tightening the rims to the This tube surrounds the shaft and is tightened on to it by the pressure of the inflating air other suitable whereby the core is better secured to the shaft while the latter rotates in the course of the moulding Preferably the tube is made from a synthetic that can be welded to the advantageously in a zone beyond that in which clips or the like means for fastening the core to the shaft are to be If it is desired to remove the core from the hollow body after the latter has the core is ably wetted with an before moulding After the setting of the moulded body the core is deflated and withdrawn through one of the small 4 openings at the ends of the hollow whose width is only very slightly greater than the diameter of the On the other if it is desired to leave the in the hollow body as a protective its can be folded over the edges of the apertures of the hollow body at both ends and serve as gaskets for tightening the joints between the hollow body and the lids closing In either case it is preferred to tighten the of the core to the shaft by means of hose collars or the like fastening The cores according to the invention are cheap to manufacture as stated can readily be left in the as a protection from corrosive materials to be stored or Another great advantage of these cores is the small width of the terminal tures of the receptacles made with their which impair the strength of the receptacles far less than do the large manholes required for conventional cores assembled from component The invention is by way of example in the accompanying drawings in whic 1 is an axial section of an inflated core according to a first embodiment of the invention mounted on a 2 shows similarly a core according to a second embodiment of the 5 is a axial section of one end of a receptacle in which the core has been left as a The core 1 according to 1 consists of an inflatable bag of a pliable When inflated it assumes the intended inner shape of the receptacle to be in the example shown cylindrical with cambered end walls latter have central apertures round which these walls merge into outwardly extending rims The rims are slid on a rotatable shaft and the joints are tightened interiorly by means of annular rubber gaskets and exteriorly by means of clips The shaft has an inner duct 11 with outlet port 12 for the supply of pressed air serving to inflate the In the embodiment of the core according to a pliable tube which may consist of the same material as the bag extends axially through the bag into the rims 5 to whose edges its ends are welded at 14 and In this case the gaskets 8 of 1 are The clips gripping the rims tighten the ends of the tube 13 on to the shaft The pressurized inflating air in ing the tube on to the shaft and thus firmly secures the core to the shaft in the course of the manufacture of the When the core is intended to remain in the receptacle after the latter has the welds 15 6 are severed and the rims 5 are folded outwards over the edges of the terminal apertures of the the latter is withdrawn from the shaft the tube 13 remains on the shaft and can be welded to the rims at the ends of a new Where the core is to remain in the receptacle as a lining it is preferably covered with an adhesive before the moulding operation is where the core is to be removed from the moulded the core is preferably covered with an before the moulding In an arrangement like that of the rim 5 of the core which latter a lining of the serves as a gasket for tightening the joint between the edge if the aperture of the receptacle and the lid with which this aperture will have to be insufficientOCRQuality

Claims (10)

- 7 - 29082/2 C IMS

1. A core for the manufacture of hollow bodies, especially receptacles, from mouldable synthetic-resin compositions, comprising an inflatable bag of pliable synthetic-resin foil which, in the inflated state, assumes the intended shape of the inner space of the hollow body and which has at both ends apertures surrounded by rims which, in the inflated state of the core, become tightened hermetically onto a rotatable shaft.

2. A core according to Claim 1, wherein a pliable tube extends coaxially through the bag into the rims of the apertures at both ends.

3. A core according to Claim 2, wherein the tube consists of a material capable of being welded to the rims of the core, preferably in a zone beyond that in which clips or the like means for fastening the core to the shaft are to be located.

4. Cores for the manufacture of hollow bodies from mouldable synthetic-resin compositions, substantially as described herein and illustrated in the accompanying drawings.

5. A process for the manufacture of hollow bodies with the aid of cores according to any of Claims 1 to 4» wherein the core, preferably wetted with an anti-adhesive, is mounted on a rotatable shaft and inflated, and after the setting of the hollow body moulded on the inflated - 8 - 29082/2 core, the core is deflated and withdrawn from the hollow body through one of the terminal apertures thereof.

6. A process for the manufacture of hollow bodies having a protective inner lining, wherein a core according to any of Claims 1 to 4, preferably coated with an adhesive, is mounted on a rotatable shaft and inflated, and after the setting of the hollow body moulded on the inflated core the shaft is detached from the core and withdrawn while the core is left within the moulded body as a lining.

7. A process according to Claim 6, wherein the rims of the core are bent over the edges of the terminal apertures of the moulded body after the latter has set.

8. A process according to Claim 6 or 7» wherein a core according to Claim 3 is used, the inner tube is welded to the rims of the core before the moulding operation, and the welds are severed after the moulding operation.

9. Moulded hollow bodies of synthetic-resin compositions made by the processes accordin-j to any of Claims 6 to 8 and containing the core as a lining.

10. Moulded hollow bodies according to Claim 9, wherein the rimsof the core are bent over the edges of the terminal apertures of the hollow bodies. For the Applicants PARTNERS RC/rb