Abstract: A method is disclosed for making a three layered parison for blow molding a biaxially oriented hollow article of thermoplastic material. One end portion of an extruded tubular body is heated to welding temperature and closed to a bottom by a forming step. The central layer of the multilayered body is removed from part of the end portion before the forming step takes place to insure that the central barrier layer of the body allows for an intimate welding together of the inner and outer layer. A similar operation is used in making the finish portion of a container at the opposite end of the tubular body.

Abstract: The heated end of a parison is brought into a finish mold form to shape a finish profile suitable for setting up a closure. The parison is axially stretched by a stretch pin to pull out the heated plastic material adjacent the profile to a thinner cross section. This allows to obtain a considerable saving of weight of the plastic material.

Abstract: The heated end of a parison is brought into a finish mold form to shape a finish profile suitable for setting up a closure. The parison is axially stretched by a stretch pin to pull out the heated plastic material adjacent the profile to a thinner cross section. This allows to obtain a considerable saving of weight of the plastic material.

Abstract: An apparatus to make articles, in particular bottles, from parisons in a blow mold operation. The parisons are carried on transfer mandrels throughout the operation. The parisons riding on the transfer mandrels are heated while travelling around on a first wheel and are transferred into blow mold units mounted on a second wheel. Each blow mold unit is provided with an expanding mandrel which is extended through the transfer mandrel into the parisons. Two different blowing pressures are used in the blowing step which is controlled by cam controlled valves. From the second wheel the mandrels carrying the blown articles are transferred to an output wheel where the articles are removed from the transfer mandrels which are returned to the first wheel.

Abstract: A method for blow molding containers and the like articles from thermoplastic parisons. The parisons are heated in two stages, i.e., in a pre-heating oven to a uniform temperature less than the blow molding temperature and by infra red radiation to a final blow molding temperature which, preferably, is non-uniform along the length of the parison. The non-uniform heating is accomplished by moving the parison axially through an annular infra red radiator at varying rates of speed. Since the degree of heating is directly proportional to the time of exposure to the radiation, a variable temperature profile can be imparted to the parison by means of a simple speed program. Such a variable temperature profile results in controlled wall thickness distribution during blow molding, and the final container is of enhanced strength and of lower weight.

Abstract: Workpieces of a synthetic plastics material are heated to enable further lding thereof to be effected. Heating is effected by infra-red radiators and, in order to ensure that localized overheating is avoided, the surface of the workpiece which is exposed to radiation is cooled during the heating process.

Abstract: Hollow articles of thermoplastics, especially bottles, are made from tubular blanks by heating the ends thereof and press molding first their bottom and neck portion. Then the preformed blanks are heated around their center portion and are transferred into blow molds for inflating them to the final shape. The machine consists of a first rotary table with preheating and press molding means, a second rotary table with final heating means and a third rotary table with blow molds. The rotary tables are connected by transfer stations so that the blanks can be automatically transmitted and conveyed around all tables. The high throughput allows installation before racking plants.

Abstract: In a blow-moulding process, the base of a hollow plastics body is formed initially of convex configuration and then a portion of the base is deformed inwardly to provide a concave area surrounded by an annular support surface. Deformation of the base is controlled in response to an increase of pressure in the mold cavity after termination of venting thereof.

Abstract: A tubular slug of thermoplastic material is preheated and is then gripped a position spaced from an open end of the slug, the gripping means being such as to effect a reduction in cross-section of the gripped portion of the slug. Such reduction in cross-section provides a shoulder which abuts the gripping means during application of pressure to the end face of the slug to deform the end portion thereof to provide a thread, groove or other profiled formation.