International projectionist (Jan 1943-Dec 1944)

the motor shaft and proceed to put a counter-shaft with two pulleys, one 1" grooved pulley and one 5" grooved pulley on the counter-shaft. The speed of the shaft when hooked up from the motor to the 5" pulley will give the speed of the shaft as 1/5 of the speed of the motor. Then I would line up the 1" grooved pulley on the countershaft with the crank-shaft gear of the projector head which is also grooved, and use that gear as a drive. The crankshaft gear will take care of the soundhead as before I had trouble the soundhead drove the projector. I would make a slot in the housing of the projector head so that the belt can enter to drive the gears, which reduces the speed of the projector to 1/20 of the motor. Thus normal speed of the projector will be obtained." Fred Bendell, the second prize winner, has soundheads that are driven in the same manner and he has assumed that only the coupling fails. Here are excerpts from his solution: "I would keep the projector going by using a metal sleeve that comes with the equipment to align the soundhead shaft and the motor shaft. This shaft is slipped over the soundhead shaft and then the motor is brought in to line by adjusting the bolts on the bracket holding the motor. When motor shaft and soundhead shaft are in perfect alignment this sleeve slips over both shafts with ease. Now I would drill and tap holes for screws about ^4-inch from either end of the sleeve and then slip the sleeve over the soundhead shaft and motor shaft and tighten up the screws and so couple my motor to the soundhead. I have already taken off our coupling and tried this sleeve out. I find that there is a little more vibration to the machine, but it does not affect sound or picture. I find that this sleeve could be put on between reels." George J. Beltz, the third prize winner, also has the same type of drive and he likewise assumes that the coupling, only, fails. You will note from the following quotations that his approach is quite a bit different: This coupling is really a sort of filter acting between the motor and soundhead and assembled with three pieces of metal. One piece is locked with set screws on the shaft of the motor and another on the shaft of the gear box. The third is set in a floating position so as not to touch the other two. This position is held and maintained by a heavy composition ring riveted on both sides of the floating bar and to each of the metal clamps on each shaft. * * * To make an emergency repair, leather belting could be threaded through the clearance between the metal parts and the entire coupling could be held together with heavy twine tied around it to keep the belting in place. If this is not available a piece of rubber innertube could be used instead, or even lightweight sash cord pounded flat and inserted to keep the show going for the night. After the show, couplings could be taken off the shafts and new rings made from shoe leather could be riveted to the proper parts." Frank C. Champlin proposes to substitute a belt drive for a coupling that has failed. He uses two pulleys of the same diameter in the following manner: "By taking two pulleys for use with a V-belt, and placing them on the two respective shafts and coupling them together with a V-belt you are on with the show. Of course it is also understood that the motor must be placed on an improvised mounting so that the shafts are in proper relation to each other to enable you to use said arrangement. Use of a V-belt greatly lowers the chance of slippage and it is believed that with proper alignment and care not a particle of difference between the two drives would be noticed. Use of two pulleys on each shaft and two V-belts would cinch the matter, but these shafts are not long enough to accomnfodate such an arrangement. The hardware store has the pulleys and there are lots of employees' cars having the V-belts that would work in a pinch, although the proper thing is a belt to fit the taper of the pulleys." John Lawrence solves the problem by using a flat belt in place of chain drive. We acknowledge the solution as ingenious, but the belt is rather narrow and before committing ourselves to its workability would like a report that it has actually functioned. Anyway here is his proposal: "If this chain link belt were to break I would immediately send for a %" flat leather belt. I would fasten the ends with rawhide lacing and use the belt instead, using the gears as ordinary flat pulleys until closing time. I would then proceed to fill the teeth of the gears with lead or plastic composition to make a fiat running surface." Raymond J. Mellien would use garden hose as a substitute for a flexible coupling, but recognizes the possibility of slippage between the coupling and the shafts. He writes: "Therefore, in case of emergency I would purchase from a hardware store a piece of garden hose Yz" in diameter. This piece of hose is to be slipped over the two shafts to act as a flexible coupling, but before applying the hose, I would give the two shafts a coat of rubber or patching cement. This would help prevent slipping due to the quick starting of the motor. Of course, a hose clamp on each end of the hose, over each shaft, is necessary to be sure of a tight fit." Maurice Rushworth not only considers the possibility of the flexible coupling failing, but also that trouble may develop in the gear box also. With regard to the coupling, he proposes: "The actual coupling can be easily replaced by a small length of garden hose and clamps. Both shafts have flattened surfaces for the set screws and if the hose is split, fitted and the two straps bound tightly, I see no reason why the temporary repair should not last for 'some weeks'." He then proceeds to take care of trouble in the gear box as follows: "In case of teeth stripping, an expert machinist could cut new teeth if the metal had first been built up. * * * In normal times it would not be such a problem, but now it would be almost impossible. The best I could do would be to contact a friend of mine and after having the metal built up attempt to hand cut the teeth, hoping that the matching would be good enough so that vibration would not be transmitted through the system. * * * It is possible that the Woodruff keys might split. There would be enough of the key left to use if solder were dropped in the slot. You couldn't solder steel, but the key will keep the solder in place. Drop solder in the slot, fit the key and if necessary grind down a little." H. D. Taylor, has selected a length of heater hose, as a substitute for the flexible coupling. Here are excerpts from his analysis: "A size of heater hose available at automobile supply stores has an inside diameter of Yi ", ' which will fit snugly over the shaft ends. The supply store also can furnish clamps that are made to fit around the outside of the hose. To avoid any tendency of the hose slipping on the shafts, the flat on the shafts and the part of the clamp that carries the clamping screw can be placed adjacent to each other and the clamps tightened until the hose takes the shape of the shaft at that point." As an alternative, in case the hose and clamps were not available he would arrange a belt drive, using available grooved pulleys. He is fortunate in having two 134" pulleys that are grooved (Continued on page 26) Have You Applied for Your Repurchase Priority? APRIL 1943 17