Abstract: A blow-molding machine for producing blow-molded hollow bodies from a thermoplastic material, includes two blow-mold halves which can be horizontally displaced and provided with separate drive units for a transport drive and for the sequence of movements of the mold closing and locking device to open and close the blow mold halves. Conventional blow-molding machines are still equipped with hydraulic drives at least for the mold closing and locking device. In order to provide a blow-molding machine that can for example be operated under clean-room conditions, the drive unit of the blow-molding machine according to the invention is configured for the clamping elements of the mold closing and locking device as an electromotive direct drive with a spindle drive and a spindle mechanism with recirculating rollers.

Abstract: A blow-molding machine for producing blow-molded hollow bodies from a thermoplastic material, includes two blow-mold halves which can be horizontally displaced and provided with separate drive units for a transport drive and for the sequence of movements of the mold closing and locking device to open and close the blow mold halves. Conventional blow-molding machines are still equipped with hydraulic drives at least for the mold closing and locking device. In order to provide a blow-molding machine that can for example be operated under clean-room conditions, the drive unit of the blow-molding machine according to the invention is configured for the clamping elements of the mold closing and locking device as an electromotive direct drive with a spindle drive and a spindle mechanism with recirculating rollers.

Abstract: In a process and apparatus for producing hollow bodies from thermoplastic material by blow molding of preforms using a closing support structure having at least first and second blow molding molds, a common drive means engages a drive plate and a first carrier plate which carries a mold portion. The drive plate is connected to a second carrier plate carrying another mold portion. At least one further carrier plate is arranged displaceably in the opening and closing direction between the first and second carrier plates. At each of its two sides the further carrier plate carries a respective mold portion, each thereof with a mold portion carried by an adjacent carrier plate forming a respective blow molding mold. Each of the two blow molding molds afforded thereby is provided with a means for locking the respective mold in the closed condition thereof.

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 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: An apparatus for the production of hollow bodies from thermoplastic material by blow molding using 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: 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: In a process and apparatus for the discontinuous production of preforms for producing hollow bodies from thermoplastic material, the wall of which is a laminate having at least first and second layers, by extrusion blow molding, the flow of material for forming the laminate is guided within the extrusion head which serves to produce the preforms, by suitable dimensioning of the volume of the duct system accommodating the laminate, such that regions of disturbed laminate occur in the end portions of the preform which are squeezed off the extruded preform by the blow molding mold as a waste portion.

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: During the production of a preform of thermoplastic synthetic material by means of extrusion from an extruder head provided with a slot-shaped exit opening, the width of which is changed according to a specific program during the extrusion of the preform in order to change the wall thickness thereof, the wall thickness of at least one section of the preform should be controlled by at least one additional program, which is superposed on at least one portion of the first program, which is longer than the additional program. In this manner, one achieves greater flexibility in respect to fulfilling the requirements of each situation on the programming, namely both in respect to the resolution and in respect to precise determination of the location of the individual switch points, even when a very great number of changes of the slot width must be undertaken over a very short section of the preform or during a very short time period during the extrusion process.

Abstract: Apparatus for the production of hollow articles of thermoplastics material by a blowing process, comprising a hollow mould in which a preform blank is arranged to be expanded by the application of blowing pressure, the mould being formed in at least two parts with the mould parts being movable relative to one another, means supporting said mould parts, means for effective relative movement of the mould parts, and means for taking up the forces resulting from the blowing pressure, comprising a closed frame on which the mould parts are arranged and which comprises upper and lower tie members with side pieces extending therebetween to connect the tie members, the upper and lower tie members being arranged to lie in respective vertical planes which are spaced from one another, and the side pieces being orientated at an acute angle relative to the horizontal.