초록 ▼

In a machine for making two-piece flat bottom paper cups, having a mandrel on which the cup is formed, the portions of the two blanks that are to form the bottom seam are heated by a device comprising a stationary air duct with which the mandrel can be coaxially aligned. Air flowing forwardly in the

In a machine for making two-piece flat bottom paper cups, having a mandrel on which the cup is formed, the portions of the two blanks that are to form the bottom seam are heated by a device comprising a stationary air duct with which the mandrel can be coaxially aligned. Air flowing forwardly in the duct from an inlet at its rear is heated by an electric element therein. On the front of the duct a nozzle is mounted to slide between a forward operative position and a rearward inoperative one. Cooperating throttle elements on the nozzle and the duct restrict flow to radial outlets in the nozzle when it is in operative position, ensuring steady air flow through the duct. An annular heat shield around the nozzle enables it to effect combined radiant and hot air heating. All heaters are arranged for retraction if the machine stops for longer than a normal dwell period.

대표청구항 ▼

In a machine for making cups of thermoplastic coated paper, each comprising a side wall blank and a disc-like bottom wall blank that has its margin formed as a circumferential axially projecting flange portion, said machine comprising a mandrel around which a side wall blank is rolled and which has

In a machine for making cups of thermoplastic coated paper, each comprising a side wall blank and a disc-like bottom wall blank that has its margin formed as a circumferential axially projecting flange portion, said machine comprising a mandrel around which a side wall blank is rolled and which has at an outer end thereof a flat outwardly facing surface against which a bottom wall blank is held with its flange portion projecting outwardly and surrounded by a bottom portion of the rolled side wall blank, heating means for melting coating on said portions of the blanks to provide for their adhesion to one another, said heating means comprising: A. an air duct with which the mandrel has coaxial alignment and which has a rear end remote from the mandrel, said air duct having near its rear end an inlet connectable with a source of air under substantially constant pressure; B. an electric heater in said air duct by which air is heated in flowing forwardly through said duct from said inlet; C. a nozzle on the front end portion of said air duct, coaxially slidable relative thereto between a forward operative position in which said nozzle is substantially concentrically received within said portions of blanks on the mandrel and a retracted rearward position in which the nozzle is spaced a substantial distance outwardly from the mandrel, said nozzle (1) being closed at its front end and (2) having radially opening outlets near its front end from which air that has passed through the air duct is emitted for heating said portions of blanks on the mandrel when the nozzle is in its operative position; and D. cooperating coaxial throttling means in said nozzle and said duct, arranged to define a restricted annular passage through which air flows in passing from the air duct into the nozzle when the nozzle is in its retracted position but to provide for substantially unrestricted flow from the air duct into the nozzle when the nozzle is in its operative position.