Pressing units attached on the calender
Pressing units attached on the calender and consisting of a tie rod and a piston-cylinder unit actuating the latter press together the two parts or halves of a horizontally divided or split extruder head secured on the extruder. This creates a union between extruder and calender releasable for cleaning purposes, but which never permits using the extruder without the calender and which also does not permit adjusting the distance between the mouthpiece of the extruder head and the nip of the calender during operation, as would be of advantage for adjustment of the optimal working of the extruded product in the roller gap.
There has become known an extruder calender combination whose two extruder head halves are held together by several piston-cylinder units which, arranged in vertical direction, bring about also the undisplaceable relation of extruder and calender during operation. This undisplaceable relation of the extruder and calender is a disadvantage in cases where, for reasons of adjusting the treatment intensity in the roller gap, the distance between extruder and calender is to be changed during operation, as has been proposed in DE-PS 40 09 917. It is here necessary to take the extruder head of the extruder off the calender entirely to be able to displace the two units relative to each other during operation.The invention avoids these disadvantages. It is the object of the invention to mount the piston-cylinder units clamping the extruder head together so that the extruder with the extruder head fastened thereon can be used also without a calender for the production of uncalendered or unsmoothed plates, and that the distance of the extruder from the calender can be changed also during operation. It is another object of the present invention to mount the piston-cylinder units clamping the extruder head toegher so that they do not increase the weight of the extruder head bottom part, that handling is facilitated, and that they are re-usable universally for any replacement extruder head.
This is the case in a prior form of realization of the sheet production extruder, where the upper pivotable extruder head part is pressed together with the lower extruder head part by two laterally arranged piston-cylinder units, and where the piston-cylinder units are secured to the lower extruder head part by means of a joint, the axis of which is parallel to the axis of the extruder cylinder. This form of realization requires that each replacement extruder head is also equipped with a pair of piston-cylinder units, which when changing the extruder head, must be disconnected from and reconnected to their feed and discharge lines, unless it is preferred to remove the two piston-cylinder units as such from the bottom part of the replacement extruder head. This manipulation is cumbersome. With a hinged bottom part, the handling is made difficult by the piston-cylinder units being in the spread operative state.