Heating apparatus for forming laminated plastic

Claim 1

Apparatus for locally heating prior to the forming of a laminated plastic member, said apparatus including: (a) a relatively small rigid and heat conductive tubular member adapted for repeated heating to at least three hundred degrees Farenheit and resistant to cracking and abrasion; (b) a substantially rigid electrical heating means mounted within and along the length of the tubular member and fixed so as to be in close proximity to said tubular member and to heat said tubular member as electrical current is fed thereto and therethrough; (c) a base and means for securing said tubular member and said electrical heating means to this base in a substantially rigid manner; (d) means for placing and maintaining the electrical heating means within the tubular member so as to maintain a close proximity without bringing the current therethrough into conducting contact with the tubular member; (e) electrical circuit means for bringing electrical current from a supply source to the electrical heating means; (f) a variable means in the electric circuit means and disposed for adjustment so as to increase and decrease the heat developed in the electrical heating means, and (g) means for selectively connecting and disconnecting the electrical heating means from the source of electric current to provide current to heat the heating means at only a desired time period.