Abstract: A clamp-type heater for heating shoe upper portions prior to molding them comprises an inner metal form (18) and a co-operating outer band (26) of silicone rubber material. The form (18) is heated e.g. by a cartridge heater while the band (26) is heated by a radiant heater (36) arranged about its outer surface. When the inner form (18) carries a shoe upper portion into the band (26), the latter wraps round the portion and clamps it about the form to ensure efficient heat transfer. The temperature of the outer band (26) is sensed by a thermistor (46) which is accommodated in a tube (48) secured by adhesive to the outer surface of the outer band. More particularly, the tube (48) is secured to the band (26) by a line contact and its longitudinal axis extends perpendicular to the direction in which the band is stretched during the operation of the device.

Abstract: A clamp heater for heating shoe upper portions prior to molding them comprises an inner metal form and a cooperating outer band constructed of silicone rubber. The inner metal form has a cartridge heater accommodated therein. The outer band is heated by a radiant heater arranged about its outer surface. When the inner form carries a shoe upper portion into the outer band, the outer band wraps around the shoe upper portion and clamps it about the inner form, to ensure efficient heat transfer. To protect the outer band from heat damage, a temperature control device in the form of a thermostat is provided. The inner form also has a temperature control device therein. To ensure adequate heat is available in the operation of the clamp, when the inner form is moved to carry the shoe upper portion into the outer band, the temperature controls are both overridden and the heaters are rendered operative.