Portable seam welding machine for thermoplastic sheets
AssigneeG.R. Systems, Inc.
InventorsNeil A. Johnson, Philip A. Taylor
Life of this patent
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Abstract
This invention relates to machines for heating and joining thermoplastic resin sheets and more particularly relates to a portable machine which fuses together the overlapping edges of large stationary sheets as the welding machine travels along the overlapping edges. The machine is moved along the opposed edges of the sheet at a velocity which is changed so that the velocity is substantially proportional to the instantaneous temperature of the heat source. The machine is therefore accelerated or decelerated in accordance with the selected velocity change algorithm which is exponentially in the preferred embodiment.
Claims12
An improved portable seam welding machine for joining sheets of thermoplastic resins, said machine being of the type having wheels, a drive motor connected through a drive train to at least one of said wheels, heating means and feed means for feeding the opposed, overlapping edges of said sheets through the machine, wherein the improvement comprises the combination of:
- (a) a start/stop switch means for alternately starting and stopping the machine;
- (b) heating means connected to said start/stop switch for alternately being actuated and deactuated;
- and
- (c) motor speed control means connected to said switch means and said motor for alternately gradually accelerating said motor to full speed and gradually decelerating said motor to a stop in response to actuation of said start/stop switch and in accordance with a selected algorithm.
An improved method for driving a motor driven heat source along the opposed edges of relatively stationery, overlapped multiple sheets of thermoplastic resin for bonding them together, wherein the improvement comprises:
- accelerating the heat source along the edges during its heater warm up in proportion to the time rate of change of the heater temperature until it is brought up to a nominal operating velocity at the nominal operating temperature of the heater.
Dependencies are inferred from the claim text.