Patent GB-1041434-A (GB)
Title: A drive system particularly for a machine for fabricating honeycomb core
Inventor: ROHR FRED HILMER
IPC: B23K11/00
Filed: 1964-02-21
Abstract: 1,041,434. Welding by pressure. ROHR CORPORATION. Feb. 21, 1964, No. 7287/64. Heading B3R. [Also in Divisions F2 and H2] In a drive system, e.g. for a honeycomb core welding machine, driving means for moving a driven member against a stop member is deenergized after the driven member engages the stop member and the driven member is held against the stop member by a device effective on de-energization of the driving means. Each reciprocated slide of the welding machine is moved by cable wound round the helical groove 276, Fig. 21, of a drum 244 mounted on a shaft 255 passing freely through a gear-box 245. Splines 285 on the hollow output shaft of the gear-box 245 drive a clutch plate 250 pressed into engagement with a friction disc 251 bonded to the drum 244, the clutch pressure being derived from a spring 252 adjustably compressed by nuts 257 on the end of the shaft 255 which is supported in brackets 249, 256 fixed to the machine frame. A U-spring 247 restrains rotation of the casing of the gear-box 245. A reversible motor fixed to the base of the gear-box casing drives the gearing through a magnetic clutch. When the driven slide engages a stop, the reaction force rotates the gear-box casing against the action of spring 247 and a pin 301 actuates one of two micro-switches in dependence on the direction of rotation to de-energize the motor, to release the magnetic clutch and to apply a brake to lock the gear train to the gear-box casing. The machine forms honeycomb core 14, Figs. 2 and 4, of any desired length from continuous corrugated stainless steel strip 15 drawn through a guide 18 locatable manually on either side of the machine. Twelve copper electrode pins 19 having pointed chromium plated tips are insulated end embedded in a body of plastic in a slide 20 reciprocatable transversely of the core. Six or twelve electrode wheels 30 mounted on a common reciprocatable head 10 co-operate with the electrode pins 19 to make six or twelve welds on the forward stroke and in the former case to make six intervening welds on the back stroke. Current is supplied from four welding transformers each having three secondary windings connected to three wheels 30 and the associated pins 19. The welds may be continuous or intermittent. Thirteen indexing pins 21 are similarly mounted in a slide 5, Figs. 2 and 5, which is reciprocated longitudinally of the core 14 by a cable between the centre and one side of the machine determined by which of two adjustable stops 224, 225 is extended. The slide 5 moves on rails 57, 58 which are reciprocatable transversely of the core so that after each group of welds has been completed the indexing pins 21 move through a rectangular path and the core 14 is indexed and ribbon 15 is drawn from the guide 18, the electrode pins 19 being retracted during the indexing movement of the core. The electrode pins 19 are supported in grooves 107 in one of a pair of stripper bars 23, 24 on each side of the core. The indexing pins 21 internest with and are located above and between the electrode pins 19. The cross-section of the pins is as shown in Fig. 10, the recesses 92, 94 providing clearance as for burrs around perforations in the ribbon. The indexing pins 21 are provided with caps 96 the ends of which locate the ribbon prior to welding. Until the core 14 reaches a certain depth it is supported on a wooden block 191 having a profiled top and apertured in similar manner to the core 14. Pins 190 inserted through the block 191 or through the welded cells of the core 191 when the core is of sufficient depth slide along support bars 187, 188 which extend on each side of the machine to the length of the core. When the end of the core 14 is reached the pins 191, 19, 21 are retracted, the core is lowered and the pins reinserted. The stops 224, 225 are adjusted so that indexing of the core 14 takes place in the opposite direction. The guide 18 is moved to the other side of the machine so that the ribbon is looped back over the indexing pins 21, and then welding is restarted and continued automatically until the other end of the core 14 is reached. Each electrode wheel is in the form of a copper annulus 30, Fig. 16, not shown, rotatably mounted on a hub of a steel disc 116, and held thereon by a copper plate 36 bolted to the disc 116. The plate 36 and disc 116 have annular flanges 119, 115 forming bearing surfaces for and supplying current to the wheel 30. The plates 36 are pivotally mounted on members 38, Figs. 2 and 4, and are urged downwardly against stops by springs 137 the compression of which is individually adjustable to determine the welding pressure on each wheel 30. The members 38 are mounted on a plate 145 horizontally slidably supported on a plate 39 which is vertically slidable mounted on a block 44 carried by the frame 70 of the welding head. Vertical movement of the plate 39 is controlled by a cam and follower 82 to lower the wheels 30 during the forward and if desired during the rearward stroke to effect welding, the current being controlled by a cam-actuated switch 197 to produce a continuous or an intermittent weld. The plate 45 is moved to one side during the forward stroke and to the other during the rearward stroke in order that different nodes may be welded. Air is blown from jets in front of the wheels 30 to cool the wheels 30 and to press the ribbon on to the welded core. Reference is made to a modification in which the machine is shuttled continuously in one direction the core being looped back and built up as an endless belt.