Plasticizing unit for an injection molding machine

摘要

A plasticizing unit for an injection molding machine includes a plasticizing cylinder; a plurality of separately energizable resistance heaters arranged on the plasticizing cylinder; clamping sleeves surrounding the resistance heaters and oriented generally coaxially with the plasticizing cylinder; and clamping elements tightening the clamping sleeves for pressing the resistance heaters against the outer face of the plasticizing cylinder. There is provided a protective casing surrounding the plasticizing cylinder and being attached thereto. Each resistance heater comprises a flat-tube heater body including consecutive first and second length portions. The first length portion contains heating wires and has a helical course about the outer face of the plasticizing cylinder. The second length portion forms an end of the flat-tube heater body and is free from heating wires and contains the lead wires. The second length portion is bent out of the helical course of the first length portion and is accommodate in a space defined between the outer face of said plasticizing cylinder and the protective casing. A terminal panel is secured to a rear terminus of the protective casing and is oriented generally perpendicularly to the longitudinal axis of the plasticizing cylinder. Supply cables within the protective casing are connected to the end portions of the heater bodies and to terminal plugs which are supported in the terminal panel for displacements of limited extent in a direction parallel to the longitudinal axis of the plasticizing cylinder.