Patent GB-603412-A (GB)
Title: A new or improved machine for bonding materials by means of high frequency electric currents
IPC: B29C65/04
Filed: 1945-10-20
Abstract: 603,412. Seaming non-metallic sheet materials. SINGER MANUFACTURING CO. Oct. 20, 1945, No. 27653. Convention date, March 5. [Class 42(i)] A machine for bonding together plies of material by means of highfrequency electric currents, comprises a frame, feed-wheels and electrodes carried thereby, mechanism for reciprocating one of the electrodes, means for supplying high frequency electric current to the electrodes mechanism for actuating the feedwheels to cause them intermittently to advance material between the electrodes, and means for varying the action of the feed-wheels to control the rate of feed of the material, at the will of the operator and during the operation of the machine. The machine comprises a bed 10 (Figs. 1 and 2) carrying an overhanging bracket arm 11 terminating in a hollow head 12. A main shaft 15 carrying a combined driving pulley and handwheel 16 is journalled in the arm 11, and imparts intermittent rotary movements to a shaft 19 journalled in brackets beneath the bed 10, by means of an eccentric 22 rotating in a block 23 which is slidably engaged by the forked end 25 of a connecting-rod 24, the other end of which is connected to the arm 27 of a one-way clutch 28, secured on the shaft 19. A lower feed-wheel 20 is secured to the other end of the shaft 19, its periphery extending through a slot in the bed 10. In order to allow adjustment of the feed, the connecting rod 24 is pivotally connected to one end of a link 30, the other end of which is pivoted at 31 to a crank-arm 32, itself pivoted on a screw 33 threaded into a boss 33<1> on the bracket arm 11. The free end of the crank - arm 32 is slotted and engages a pin 34 on one arm of a bell-crank lever 35. journalled on stud 36 on the bracket arm 11. The end of the other arm is positioned between cams 37, 38, connected to knobs 41, 42, which govern the maximum and minimum rates of feed. A spring 101 normally urges the end of the arm into contact with the cam 37, while a chain 117 is connected to a treadle for decreasing the rate of feed when passing over crossseams. A vertical rod 46 (Fig. 3) journalled in the hollow head 12 and pressed downwards by a spring 51, has secured to its lower end a bracket 47 having lugs 48, between which is pivoted an arm 49 carrying a rotatable upper feed-wheel 50, cooperating with the lower feed-wheel 20. An upper electrode 60 is carried on a vertical bar 59 which is urged. downwardly by a spring 61 and given a reciprocating motion by a roller 68 on a bracket 66 at its upper end engaging an eccentric 69 on the end of the shaft 15. Means are provided for lifting the upper feed-roller and electrode simultaneously, comprising a hand lever 75 having a cam portion 76 which may engage an extension on a sliding collar 79. The latter when raised, lifts a Z-shaped member 80 which then engages collars 81, 62 surrounding the bars 46, 59 respectively, to lift the latter. A treadle or knee shift lever acting through a pull rod 83 (Fig. 1) arm 84 rock-shaft 85, arm 86 and link 87 may also be provided to effect this lifting. The lower electrode 70 is adjustably mounted on a block of insulating material 71, and a ledger blade 97 is secured to it, and co-operates with a trimmer knife 96 adjustably secured to, but insulated from, the reciprocable bar 59. The output of a high frequency generator or oscillator operating at 30 to 100 Mc/s is fed in through a coaxial transmission line, the outer conductor 99 being grounded, and the inner conductor 103 connected to one end of a coil 105, the other end of which is grounded. In shunt with the coil 105 is a load circuit comprising coil 108, variable condenser 109, and the electrodes 60 and 70 and the workpiece. A glow-lamp 114, visible through a lens 116 is provided to indicate resonance, the condenser 109 being adjusted by an insulated set-screw 113. Specification 599,300 is referred to.