Abstract: A barrel of thermoplastic material has a peripherally extending carrier and transportation ring in the region of its upper end portion and at least one plughole connection in the edge region of the latter. The bung hole connection is disposed within a housing which is let into the upper end portion. The housing is open at its side towards the edge of the barrel while at its other side it has a boundary end wall, from each of the two ends of which a respective wall extends towards the edge of the barrel, the walls laterally defining the housing. The walls defining the housing are delimited at the top side by a transition from the respective wall into the upper end portion of the barrel and at the lower end by a transition from the respective wall into the bottom of the housing. The spacing between the upper transitions of the two ends of the housing is greater than the spacing between the two lower transitions and the upper transitions diverge towards the edge of the barrel.

Abstract: In a process and apparatus for producing elongate curved hollow bodies at least partially comprising thermoplastic material a preform is extruded from an extrusion system head and engaged by a gripping means. The preform is moved by the gripping means into the region of a guide stencil disposed above the mold cavity of a mold portion of a divided blow molding mold and introduced into the mold cavity by a simultaneous downward movement of the gripping means and a movement following the configuration of the guide stencil. The guide stencil has two mutually opposite walls, the spacing of which increases in an upward direction and the spacing of which at the bottom of the guide stencil approximately corresponds to the maximum width of the mold cavity. The preform is thus guided towards the mold cavity by the walls, acquiring its definitive orientation with respect thereto by virtue of such guidance, passing through a lower opening in the guide stencil into the mold cavity.

Abstract: An injection molding apparatus for processing thermoplastic materials has at least one plasticizer unit, at least one injection molding cylinder with associated emptying piston, and at least one injection molding mold. The injection molding cylinder is provided with a sleeve which is arranged reciprocally between a position in which communication with the injection molding mold is interrupted and a position in which communication with the injection molding mold exists. In the position in which the communication with the injection molding mold is interrupted, a passage is provided between the sleeve and the housing which is connected between the feed conduit from the plasticizer unit and a storage space defined on the inside by the sleeve. The outside diameter of the ejection piston is slightly smaller than the inside diameter of the sleeve so that remaining between the two is an annular gap through which the plastic material passes into the storage space from one end of the sleeve.

Abstract: In a connecting arrangement on first and second parts which are to be connected, the first part carries an extension and the second part has an opening into which the extension engages when the parts are in the connected position. The extension has an aperture. A projection extending into the opening in the second part engages in the aperture when the parts are in the connected position. An arresting tongue projects into the aperture in the extension. When the two parts are brought together the arresting tongue is pivoted by the projection into the position in which it bears against a region of the boundary wall defining the opening in the first part and thus secures the parts in the connected position.

Abstract: In an apparatus for the production of hollow bodies from thermoplastic material by use of extrusion blow molding, having at least two blow molding units and an extrusion system, in an operating cycle each blow molding unit is movable between a receiving position in which the opened blow molding mold receives a preform and at least one other position in which the expanded hollow body is removed from the blow molding mold. Each blow molding unit is firstly moved from a station remote from the removal station in at least one direction into the removal station and opened after reaching the removal station, whereupon the hollow body previously produced in the blow molding mold is removed. The respective blow molding unit is then moved by use of a second movement in another direction, with the blow molding mold open, into the receiving position which is arranged laterally displaced relative to the path of movement along which the blow molding unit is moved into the removal station.

Abstract: In a process for the production of a hollow body of thermoplastic material which is to include an additional portion, by expansion of a preform in a blow molding mold, the additional portion is connected to the hollow body upon expansion of the preform to form the hollow body. To form the connection between the hollow body and the additional portion, the latter is heated by a heating element which is brought into contact with at least the surface of the additional portion that is to involve the welded connection to the hollow body, prior to expansion of the preform. The heating element is brought into contact with the additional portion when already disposed in the blow molding mold in order in that way to heat at least the appropriate surface of the additional portion to a temperature which premotes the production of an adhesive join to the hollow body. The region of the additional portion that is to be heated is at least substantially covered relative to the outside atmosphere by the heating element.

Abstract: In that process for the production of hollow bodies from thermoplastic material by extrusion blow molding in which discontinuously extruded preforms are expanded in a blow molding mold, at least during that part of the filling phase which is typical of such a process, for an extrusion head, the distance covered by an ejection piston associated with a storage chamber and the speed at which the ejection piston is displaced within the storage chamber by the plasticised material are detected and compared by a central control and regulating device to the respective reference values. On the basis of the result of the comparison operation at least one operating parameter of the process, for example the delivery output of the extruder or the extent of the emptying strike movement of the ejection piston can then be adapted while still in the same working cycle in such a way that substantially the required preform volume is ejected.

Abstract: A process and apparatus for the production of hollow bodies from thermoplastic material by means of blow molding uses a blow molding mold which includes at least first and second mold portions to enclose a generally tubular extruded preform which is expanded within the mold under the effect of an increased internal pressure within the preform. To provide for asymmetric closing and/or opening movements of the mold portions relative to the preform, the blow molding mold is displaced as an entirety parallel to the direction of the opening and/or closing movements of the mold portions, more especially during the mold closing and/or opening procedure, so that an additional motion is superimposed on the movements of the mold portions.

Abstract: An apparatus for producing a preform for the manufacture of a hollow body from thermoplastic material by extrusion blow molding has an extrusion head with a material-storage chamber which can be emptied by a piston to produce the preform. At its peripheral surface the piston has a groove-like recess providing a receiving passage which extends parallel to the direction of movement of the piston, for receiving plasticized material from the extruder connected to the extrusion head. Communicating with each of the two end regions of the receiving passage are respective duct systems through which respective flow portions of material from the extruder flow to the storage chamber.

Abstract: In a process and apparatus for the production of hollow bodies from thermoplastic material, having a wall of a laminate formed by at least first and second layers, by means of extrusion blow molding, a preform having a wall structure with a suitable number of layers is first produced in a batch-wise procedure using an extrusion head. The material required to produce the preform is guided in the extrusion head in such a way that disturbed portions of the laminate pass into the waste flash portions at the ends of the hollow body produced from the preform, so that the wall of the finished hollow body is devoid of disturbed laminate portions of that kind.

Abstract: In a process and apparatus for the production of hollow bodies from thermoplastic material, the walls of the hollow bodies are of a laminate structure having at least first and second layers, by means of extrusion blow molding, the pressure within the extrusion head and more particularly at the location at which the laminate is formed by the discharge of flows of material from a storage chamber in the head is maintained within limits such as to avoid disturbing the laminate to such an extent as to have an adverse effect on its function. The pressure at the time of a transition between filling and emptying of the storage chamber and between emptying and filling of the storage chamber is maintained substantially at a pressure level which approximately corresponds to the storage chamber emptying pressure.

Abstract: A barrel of thermoplastic material has at least one connecting portion having an emptying opening and arranged in a trough-like depression in the upper end part of the barrel. In the region of the connecting portion the barrel has at least one inclined surface which extends between the upper end part of the barrel and the side wall of the barrel. The inclined surface is of such a configuration that in a barrel emptying position the emptying opening forms the lowest part of the interior of the barrel to permit at least almost complete emptying of the barrel.

Abstract: In a process for producing a hollow body with a wall which partially comprises foamed thermoplastic material by an extrusion blow molding procedure, a preform which comprises at least first and second layers of which at least one comprises foamable plastics material is first extruded, the layer of foamable material is foamed, and then the preform is expanded in a blow molding mold by the application of an internal pressure. The hollow body may have a welded seam at a region of the hollow body at which an operation of squeezing off excess material has been carried out, the seam being in the form of an outwardly projecting flange web portion and the thickness thereof being such that the layer of foamable material is compressed at least to such an extent that it is not thicker than in the unfoamed condition.

Abstract: In extrusion blowing a hollow member, a preform is extruded and then blown in a mold to produce the final member. The weight of the hollow member is determined after its removal from the mold and compared to a reference value, thereby to adjust the size of the extrusion discharge opening to control the amount of material in the preform. The length of the preform is detected to control the movement of the mold thereby to keep a substantially constant length of extruded preform, while the time required to produce a preform is also maintained at a substantially constant value.

Abstract: In the production of a tubular extruded section of thermoplastic material, the actual length of an extruded section at the end of the extrusion operation may be smaller or greater than the length of the extruded section which passed through the discharge orifice of the extrusion head during extrusion. If the wall thickness of the extruded section is varied during extrusion in accordance with a given program, inaccuracies in regard to distribution of the wall thickness over the length of the extruded section can be reduced by detecting the length of the extruded section which passes through the discharge orifice, and controlling the means for producing the programmed variation in wall thickness, in dependence on that discharge length. The same effect can be achieved by controlling the means for producing the programmed variation in wall thickness, in dependence on discharge speed and time.

Abstract: In extrusion blowing a hollow member, a preform is extruded and then blown in a mold to produce the final member. The weight of the hollow member is determined after its removal from the mold and compared to a reference value, thereby to adjust the size of the extrusion discharge opening to control the amount of material in the preform. The length of the preform is detected to control the movement of the mold thereby to keep a substantially constant length of extruded preform, while the time required to produce a preform is also maintained at a substantially constant value.