Patent GB-1391912-A (GB)
Title: Hf generators
IPC: H05B6/50
Filed: 1971-09-18
Abstract: 1391912 Seaming non-metallic sheet material BRITISH UNITED SHOE MACHINERY CO Ltd 18 Feb 1972 [18 Sept 1971] 30044/74 Divided out of 1391911 Heading B5K [Also in Divisions H1 and H5] An H.F. generator 156 comprises output power tuning means 210 comprising two tuning members 212, 214, the member 212 being movable relative to the member 214 to effect tuning, resilient means 246 for urging the member 212 in one direction relative to the member 214, fluid pressure operated means C5 for effecting movement of the member 212 is an opposite direction against the influence of the means 246, and control means whereby the pressure applied by the means C5 to overcome the influence of the means 246 can be varied, so that the distance moved by the member 212 in said opposite direction under the influence of the means C5, and thus the output power of the generator, can also be varied. As shown, a machine for welding, welding and cutting, or embossing a workpiece, made of thermoplastic layers or non-activatable layers with a heat-activatable layer therebetween, similar to that described in Specification 1,244,655, comprises an upper presser member 142 secured by spaced insulators 140 to a plate 138 secured to a cylinder C4. A lower platen 24 is secured to a base plate 120. Strips 152, 154 connect the member 142 and the platen 24, respectively, to the generator 156. A turntable 160 is rotatably supported on a bush 162 and has a plurality of work stations, e.g. three, each having an aluminium support plate 166 with a cover 178 of polytetrafluoroethylene - coated sponge rubber. Three pneumatic trip valves V51, V52, V53 are mounted on a bracket 202 and have plungers extending along a radius of the turntable. A clamp plate 64 secures the turntable to the bush 62 and, mounted on the turntable, at equal distances about the plate 64, are three plates 204 carrying trip members 206 each associated with one of the valves V51, V52, V53. The tuning members of the means 210 comprises a movable plate 212 pivoted to a fixed wall 214 constituting the other plate. The piston rod 218 of a rolling-diaphragm piston- and-cylinder C5 receives in a bore 220 a rod 222 supported in a V-bracket 224 carried by a plate 226 on a frame 216. A trunnion block 230 is slidably received between spaced collars 228 on the rod 222 and has two spigots 232 received in bores in a bifurcated end of an arm 234 of a bell crank lever pivoted to the plate 226. The other arm 236 is pivoted to a link 240 pivoted to the plate 212. Adjustable screws 242, 244 limit the movement of the plate 212. The cylinder C5 acts against a spring 246 which normally holds the plate 212 away from the wall 214. For setting up the control means, the heightwise position of the rod 222 is adjusted by two nuts 248, 250 arranged to abut one against each arm of the bracket according to whether or not the cylinder C5 is operated. In operation, the air pressure supplied to the cylinder C5 is controlled according to which one of the valves V51, V52, V53 is tripped, the pressure being determined by regulator valves (not shown). Thus, by varying the air pressure supplied to the cylinder C5, the amount of movement of the plate 212 by the ball crank lever is varied to vary the power output of the generator.