Patent ID: 8534337
Filing Date: 2013-09-17
Classification: A41D,A41H,B29C

Abstract:
1. A high frequency sewing machine for sewing a work material H along a horizontal surface in a processing advance direction X, said work material H comprising a fiber cloth W having overlapped portions and a thermoplastic resin tape interposed between the overlapped portions of the fiber cloth, said sewing machine comprising: a sewing machine bed section having an upper wall; a work material mounting plate having an upper surface, a lower surface, a length and a width, said work material mounting plate being attached to the upper wall of said sewing machine bed section, said work material mounting plate being capable of slidingly movably mounting the work material H, said work material mounting plate comprising: an intermittent transfer device disposed in the bed section below the work material mounting plate, said intermittent transfer device capable of transferring the work material H along the horizontal surface in the processing advance direction, said intermittent transfer device comprising: a presser foot having a weight and comprising conductive metal material, said presser foot including a hold-down surface, said hold-down surface having at least a width not less than the transfer width of said feed dogs, said presser foot cooperating with the intermittent transfer device for transferring the work material H in the processing advance direction and alternatively stopping the transfer of the work material H in the processing advance direction during the transfer stopping time; a pressure rod; a fitting attachment attaching said presser foot to said pressure rod, said pressure rod and said fitting attachment supporting said presser foot and being reciprocally movable up and down; said presser foot capable of being reciprocally moved up and down when said pressure rod is moved up and down for resiliently pressing the work material H during the transfer stopping time; a lower planar electrode disposed and secured in said bed section below said work material mounting plate, said lower planar electrode comprising an electrode surface flush with the upper surface of said work material mounting plate; wherein said presser foot serves as an upper planar electrode for cooperating with said lower planar electrode, said presser foot performing a press function during the intermittent transfer of the work material H and said presser foot performing an upper electrode function during the transfer stopping time; at least one preheating heater annexed to each of said presser foot and said lower planar electrode respectively for heating said presser foot and said lower planar electrode; a heater retainer for retaining said at least one preheating heater of said presser foot in said heater retainer; at least one heat sensor attached to each of said heater retainer and lower planar electrode for performing feedback control to maintain a constant preheating temperature of said presser foot and said lower planar electrode; an arm section for operatively supporting said heater retainer; a sewing machine body for housing said arm section and said bed section, said heater retainer being operatively connected to the sewing machine body; and a heat conductive member for connecting said presser foot and said heater retainer for allowing said heater retainer and said presser foot to slide up and down and for allowing efficient preheating of said presser foot to enable stable bonding strength of the work material H including the fiber cloth W and prevent the occurrence of burn of the work material H including the fiber cloth W, said heat conductive member interposed between said presser foot and said heater retainer allowing a minimal increase in the weight of said presser foot to achieve smooth transfer and operate an optional curvilinear transfer of the work material H including the fiber cloth W and a facilitation of the operation for the optional curvilinear transfer carried out against the weight of said presser foot; said workpiece mounting plate, said feed dogs, said pressure rod and said fitting attachment being composed of engineering plastic or super engineering plastic; wherein in a state where the work material H is held between said presser foot and the lower planar electrode by moving down said presser foot during the time when the transfer by the intermittent transfer device is stopped, the overlapped portions of the fiber cloth W are continuously bonded together by allowing the thermoplastic resin tape to melt under high frequency dielectric heating by applying high frequency power between said presser foot and said lower planar electrode.