Seam welding machine for thermoplastic material
AssigneeClements National Company
InventorJohn R. Chitjian
Life of this patent
Estimating the term…
Abstract
An automatic seam welder for thermoplastic material includes a single piece frame riding on two drive wheels and a caster, the drive wheels being driven by a drive motor through a helical spring clutch. A heat gun is gimbal mounted to the frame and includes a blower, heating element, and shaped foot to direct hot air between overlapped thermoplastic sheets. A thermocouple in the foot directly senses the air temperature and, through a control circuit in a control instrument enclosure, is used to control power to the heater element. A guide wheel, foot rest and air dam are also provided.
Claims20
A seam welding apparatus for welding overlapped thermoplastic sheeting with a substantially flat seam, comprising:
- a wheel mounted frame having a plurality of wheels including at least one driven wheel linked to a means for driving said wheel and operable to drive said frame, and a dirigible wheel for steering said frame relative to a seam of overlapped thermoplastic sheeting,
- a speed control selectively operable to adjust the drive speed of said frame along said seam,
- heater means for heating air,
- blower means for generating a stream of air,
- foot means on said frame for directing a stream of air generated by said blower means and heated by said heating means to between overlapped portions of the sheeting as said frame is driven, and
- a heater control including an operator adjustable to temperature control to set outlet temperature to different levels and including a temperature sensor extending directly into the stream of heated air in said foot means to directly sense the air temperature being applied to the thermoplastic sheeting, said heater control connected to vary the supply of thermal energy by said heater means as a function of said temperature independently of a rate of flow of the stream of air and independently of environmental temperature and independently of the speed of said frame relative to the seam,
- whereby said apparatus may be driven to continuously weld the seam throughout its length.
A seam welder for fastening overlapped thermoplastic sheets, comprising:
- a rigid one piece frame;
- first and second drive wheels connected by a drive axle and mounted on said frame, said first wheel being a pressure roller wheel for sealing overlapped portions of the sheets;
- a third wheel assembly mounted on said frame and pivotable to redirect a rolling direction of said third wheel assembly relative to said frame;
- a drive assembly including a drive motor on said frame connected to drive said first and second drive wheels to drive said seam welder in a forward direction;
- a steering handle extending upwardly from said frame for manipulation to redirect a moving direction of said seam welder;
- a heat gun assembly pivotable mounted on said frame for movement between an operating and a non-operating position, said heat gun assembly including means for generating a stream of air,
- means for heating said stream of air to a predetermined temperature independently of said air stream generating means and,
- means for directing said heated stream of air between overlapped portions of the thermoplastic sheets when in said operating position to form a heat welded seam;
- said pressure roller wheel following said heated air directing means relative to the forward direction to seal the heat welded seam;
- means for selectively adjusting spacing between said pressure roller wheel and said heated air directing means when in said operating position to provide a plurality of different working positions to accommodate different materials;
- and
- control means connected to said heat gun assembly for controlling the heated air stream.
Dependencies are inferred from the claim text.