摘要:
An improved apparatus and method for joining two or more thin sheets of thermoplastic materials along a welded seam includes a welding assembly and a means for feeding the thermoplastic sheets to the working area of the welding assembly. The welding assembly includes a heated platen welding press coupled with a welding tool, an energy generator electrically connected to the welding tool and control means electrically connected to the welding press, the welding tool and the energy generator. The welding press includes a pair of opposed platens, means for heating each of the platens and pressing means for displacing at least one of the opposed platens in the thickness direction of the thermoplastic sheets. Pressure is applied to the thermoplastic sheets by using the pressing means to displace at least one of the heated platens in the thickness direction of the thermoplastic sheets. Heat produced by the heating means is then transferred to the thermoplastic sheets by the heated platens to raise the temperature of the thermoplastic sheets in the area of the welded seam to a first predetermined temperature which is below the softening temperature of the thermoplastic materials. High frequency energy produced by the energy generator is then conducted to the thermoplastic sheets by the welding tool to raise the temperature of the thermoplastic sheets in the area of the welded seam to a second predetermined temperature which is above the softening temperature but below the melt point of the thermoplastic materials. Conduction of the high frequency energy is then discontinued so that the thermoplastic sheets fuse together along the welded seam under applied pressure. Application of the pressure is then discontinued so that the welded thermoplastic sheets may be removed from the welding assembly.
摘要:
A method and apparatus for supporting sheet material such as cloth during operations thereon such as cutting wherein a pattern is placed on a supporting surface provided with a plurality of pins extending through apertures in the surface, the pins are lowered below the surface for removal of the pattern whereupon sheet material is placed on the surface, typically a plurality of plies being layed up in a stack, and simultaneously the pins are moved through the sheet material to maintain alignment and matching of the plies in the stack. The pattern then is placed on the sheet material in a position determined by the location of the pins, and the material is shaped such as by cutting. A plurality of separate pin holding and supporting devices of narrow width are spaced lengthwise along the apparatus and independently movable lengthwise toward and away from each other. Pins of adjacent rows can be closely spaced together thereby achieving a grid pattern wherein the pins are relatively closely spaced. There is provided apparatus for developing a positive pressure which is employed to apply a flotation force to sheet material on the surface to facilitate movement of the material along the surface, apparatus for developing a negative pressure which is employed to apply a hold down force to sheet material on the surface to facilitate operating on the material, and apparatus for controlling selection of positive or negative pressure so developed.
摘要:
The invention concerns how the loop portion of a VELCRO fastener can be RF welded to a compression sleeve or other similar article. By using a simpler two-step method, in which the loop portion is provided with a backing laminated thereto, both labor and material costs have been reduced over the prior art five-step method.