Abstract: A method of manufacturing of continuous, at least two-layer products having an upper layer formed of a lacquer material, the method having the steps of providing an apparatus including a co-extrusion tool having first and second conduits, respectively, with the first and second inlets, with the second conduit circumscribing the first conduit, and a merging section in which flows exiting the first and second conduits merge, and first and second extruders connected with the first and second inlets, respectively, and simultaneously injecting melts of base and lacquer materials with the first and second extruders, respectively, through the first and second conduits, respectively, so that on at least two-layer product exiting the merging section of the co-extrusion tool and having an upper lacquer layer, is produced in a single step.

Abstract: A drive for a two-worm extruder has a housing, an electric motor secured to the housing and having a motor output rotatable about a motor axis therein, and a planetary gear transmission in the housing including a sun gear, a ring gear coaxially surrounding the sun gear, and a driven planet gear in mesh between the sun and ring gear. A first output shaft extends axially through the planetary transmission within the ring gear and has an outer end adapted to be secured to one of the worms of the extruder. A second output shaft carried on the sun gear has an outer end adjacent that of the first output shaft and is adapted to be secured to the other worm of the extruder. A force-splitter includes a continuous-mesh gear train connected to the first shaft, to the planet gear, and to the motor output for driving the first shaft and the planet gear from the motor output. At least two further idling planet gears are journaled in the housing and each in mesh between the sun gear and the ring gear.

Abstract: A worm press extruder or the like includes a worm shaft which conveys a flow medium within a housing cylinder. In order to provide the medium with an appropriate pressure and temperature the worm shaft cooperates with a constriction plate so as to define a gap therebetween. The gap is controlled by heat responsive unit e.g. a bolt of high thermal expansion coefficient which is connected to a stationary portion of the housing as well as to another housing portion which is movable with respect to the stationary housing portion by lever means. Consequently, when the temperature of the bolt is changed its length is altered thus causing the other housing portion which is associated with the constriction plate to shift towards the stationary housing portion. Since the worm shaft is supported by the stationary housing portion and cannot move axially with respect to the latter, the movement of the constriction plate causes a modification of the gap.

Abstract: An extruder is controlled in response to the thickness measurement of the extruded strand. The thickness measuring head is initially given a displacement transverse to the extrusion direction, preferably around the extruded strand and the output signals from the head are integrated to form a mean value around the periphery. A comparison of this mean value with the set point wall thickness value is then utilized to provide continuous correction of the output of the head which is utilized to regulate the extruder operation.

Abstract: A drive for an extruder worm centered on an axis has a substantially closed housing axially juxtaposed with the worm, an input shaft extending along and rotatable in the housing about the axis, exposed axially at an input side of the housing, and adapted to be coupled to a drive motor, and an output shaft rotatable in the housing about the axis, exposed at an input side of the housing, and adapted to be coupled directly to the worm. An axial-thrust bearing is braced between the output shaft and the housing. A planetary transmission centered on the axis between the input and output shafts in the housing has a sun gear rotationally coupled to the input shaft, a ring gear spaced radially outward from the sun gear, a plurality of planet gears meshing with the sun and ring gears, and a planet carrier carrying the planet gears and rotationally fixed to the output shaft. The shafts, sun gear, and carrier are formed at the axis with coaxial axially throughgoing passages.