| 摘要 |
1300256 Seaming non-metallic sheet material J-C DELPY 16 March 1970 [18 March 1969] 12551/70 Heading B5K Apparatus for welding together two thermoplastic surfaces comprises a heating element 1 movable for interposition between the surfaces, the element 1 comprising a heating resistance disposed between two walls which are good heat conductors; a movable presser adapted to apply the surfaces against the element 1 and against each other after the element 1 has been withdrawn; and timed control means to control the movements of the element 1 and the presser 5 in order to regulate the period during which the element 1 is interposed between the surfaces and the presser 5 is applied. The element 1 is carried by a thermally insulated support 12 displaceable in the direction of an arrow 8 by a solenoid 3 the armature 13 of which is secured to the support 12. The movement of the support 12 is guided by rods 14 carrying return springs 4. The element 1 is suspended by four springs 2 slidable along two parallel rods 16. Control of the temperature of the element 1 is achieved by a rheostat or a regulatable bimetallic element, e.g. a thermostat. The presser 5 is lowered by a solenoid 6 to apply the two surfaces to be welded, e.g. the two ends 11, 11<SP>1</SP> of a banding strip, against the element 1 and against each other to effect welding after the element 1 has been withdrawn. When the current supply to the solenoid 6 is cut off, the presser 5 is lifted by return springs 7. The solenoids 3, 6 are operated by a programmer 9 having a manual button 10 to trigger an operating cycle. In one embodiment, Fig. 6, the heating element comprises a metal tube 21 (or folded metal plate) placed over a heating resistance 22, covered by insulating layers 24, the tube being flattened at 21a, 21b. The tube 21 is closed at one end by welding or brazing and is open at the other end to allow conductors to be connected to the resistance. The resistance 22, Fig. 8, may comprise a double-winding 22a on a flat support 22b, the turns of the windings being closer together in the front part of the element. In other embodiments, the resistance comprises a winding in the form of a flat rectangular double spiral, Fig. 9 (not shown), or a resistance wound on a thread of asbestos, Fig. 10 (not shown). In a further embodiment, the heating element consists of an armoured wire disposed in a flat configuration and the walls to contact the surfaces to be welded are constituted by a metallic coating on the armouring of the wire, e.g. formed by depositing copper thereon. |
