| 摘要 |
987,120. Seaming non-metallic sheet material. NATIONAL DISTILLERS & CHEMICAL CORPORATION. March 20, 1962 [April 26, 1961], No. 10682/62. Heading B5K. A sealer for sealing wrapped packages comprises a heating member 23 mounted on a base 22, having heating element means 68 engaging the outer surface of and insulated from the member 23, and being spring-like to permit depression thereof when applied to a package to be sealed. The sealer head 11 is mounted on a stand 12 by a hanger 27 and connected by a cable 13 to a control box 10. The base 22 is made from insulating material and the heating member 23 comprises a spring strip having the ends thereof rigidly secured to the base 22. Connectors 67 on one end of the heating wires 68 engage fingers 66 on a plate 65 and connectors 94 on the other ends thereof engage tension springs 88 mounted on a plate 70 to hold the wires 68 in engagement with the member 23. Low resistance heads 91 connected to the plate 70 pass along the springs 88. High energy leads 84, 85 of the cable 13 are connected to the plate 70 and the member 23 respectively. A roll wheel 53 operates a switch 52 having a central pole 73 to selectively engage either of contacts 74, 75. If it is desired to apply a large pulse of current for a short time to the wires 68 a control dial 16 is suitably adjusted and the roll wheel 53 rotated to the " low " position. If this heat is insufficient, the wheel 53 is rotated to the " high " position so that current flows for a longer period of time, this being adjusted by a control 17. The electrical control circuit is described in the Specification. To resist the adhesion of the member 23 to the thermoplastic film to be sealed it is covered preferably with a plastic-coated glass fibre fabric 96. The heater wires 68 are preferably made of a nickelchrome alloy, are 1/16 inch wide and 0.0005 inch thick and have a resistance of 1.723 ohms pe foot. The wires 68 are also coated, preferably with polytetrafluoroethylene. In a modification, Fig. 12, a snap switch 175 is set to either the " high " or " low " position before use and during sealing the operator depresses a switch 177 to supply current to the wires 190. |
