Exhibitors Herald World (Oct-Dec 1930)

60 Better Theatres Section November 22, 1930 EQUIPMENT AFFAIRS • • news and comment about products and people in the field of theatre equipment and supplies Conducted by G . J . R e i d HOW he came to invent the Golde changeover device, and why he designed it as he did, was recently described to us by M. H. Goldberg. Mr. Goldberg is president of the Golde Manufacturing Company of Chicago, makers of this projection accessory which is called the "Manumatic" changeover. Wishing to devise something that would effect a smooth changeover rapidly with just the pushing of a lever placed in some handy place Goldberg at first began a series of experiments using electricity. He ultimately rejected electricity, he said, because he felt that electrical apparatus might give off radio waves that would set up stray noises in the sound channels. Fire hazard was another reason for his rejecting this. Also he feared that the necessary magnets and solenoids might stick at the wrong time. He finally decided to make his changeover device mechanical. This mechanical changeover device was designed to be attached to the projector between the framing light shield, or rear shutter, and the fire shutter. It is contained in an oblong box with a black crackle finish, which is screwed on the projector head. Out of one end of the box projects a nickeled handle, while from the other end a very thin brass tube runs overhead to a device identically the same attached to the other projector. Light is let through for framing by pulling the lever out as it is pushed down. This holds the gate up without tripping the other shutter mechanism. When the frame is in position, the lever released, and the gate drops back, while the changeover automatically becomes ready to snap the gate open. The operating lever has a pin through its inner end, and the pin catches on the hooked ends of two other levers, which move the wire in the tube to trip the shutter on the other projector, and also to receive the action of the wire when the changeover is operated from the other projector. Prior to bringing out his automatic changeover device, Mr. Goldberg invented a number of projection accessories now being widely used. One came soon after the appearance of sound-onfilm recording, with its narrower frame. Mr. Goldberg's device, now well known as the Unilens method, employed changeable apertures on one unit. Other inventions of his are an automatic rewind, a framing light shield and a de vice for assuring true contacts in the lapping of carbon jaws. Mr. Goldberg was a projectionist for many years before entering upon the manufacture of projection accessories. A New Variable Gear • One of the recent designs in variable speed transmissions, and one said to be the first all-metal product of this kind on the market, is the P. I. V. (positive, infinitely variable) gear, a product of the Link-Belt Company of Chicago. This new speed change unit consists of two pairs of wheels of the opposed conical disc type, between which a chain of unusual construction transmits power. On changing speed, the selfpitching chain rises in one set of wheels and descends in the other, so that while the input shaft connected to the motor, or other source of power, turns at constant speed, the output shaft is brought to the desired r. p. m. A feature of the P. I. V. gear is its use of a positive chain drive to transmit power. Radial teeth are cut in the conical faces of the driving discs, and the self-adjusting teeth projecting beyond the sides of the chain are arranged to engage positively the radial teeth of the discs. The chain, which has been mentioned, is made up of a series of steel leaves, or links, with joints made of hardened steels pins, which turn in segmental bushings. It has no teeth on the inside surface. Instead, there are packs of hardened steel laminations, which extend through clots in the links at right angles to them, projecting about oneeighth of an inch at either side. Individual containers holding the packs of laminations, or slats, are secured in the openings of the links. The teeth on the discs are uniform in depth but widen from the center outward, being staggered relatively on each pair of wheels, so that the slats move back and forth into them to mesh correctly as the chain comes in contact with the wheels, which gives the chain a "selfpitching" feature. The slats are regrouped within their containers at each engagement of the chain and wheels, the movement in engaging being completed before the load is applied. An oil-tight housing covers all the elements of the mechanism, which are automatically splash-lubricated. The hardened steel wheel faces are mounted on cast iron hubs backed by all thrust bearings, and move axially on the shafts, which are mounted in radial ball bearings. A pair of pivotal levers operated through a hand control shaft, with right and left hand screw motion, controls the movement of the pairs of wheels together or apart. Initial chain tension is provided for by an external adjustment screw, and two hardened shoes, which ride lightlv on both upper and lower strands of the chain, under constant spring pressure, maintain the operating tension at all of the ratio settings. booklets . . . briefly describing the new brochures and bulletins issued by manufacturers and distributors on their product. Those of further interest may be procured directly from their publishers or through Better Theatres. Manufacturers and distributors are invited to send in their publications immediately upon their issuance for review in this department Lighting Equipment • The line of the Belson Manufacturing Company (Chicago), manufacturers of Bel-Sun-Lite lighting equipment and accessories for flood, stage and other types of illumination, is presented with the latest data on these products in a new catalog just issued. The booklet presents Bel-Crome as a newly discovered alloy of chromium to be used as reflecting material at all indicated parts of Belson equipment. The kinds of product treated are reflectors, lenses, borderlights, footlights, reflectors, striplights, cove lighting units, flood projectors, spotlights, exit and directional signs, louvre lights and also units for display lighting. For this product is given all necessary information for selecting and ordering — descriptive data, sizes, weight, models and prices. The booklet is profusely illustrated with diagrams and halftones. Electrical Equipment • A new comprehensive catalog has just been issued by the Westinghouse Electric and Manufacturing Company (East Pittsburgh, Pa.). This issue is its General Catalog, 1931-1932, containing 1,352 pages and describing and illustrating the great array of products put out by this company. The catalog presents complete listings of distribution apparatus, switchgear apparatus (except large oil circuit-breakers and power switchboards), lighting equipment, domestic appliances, gearing apparatus, and current-collecting devices; condensed listings of industrial motors and control apparatus, industrial heating apparatus, and commercial cooking equipment; and descriptions of other products. Style numbers, assigned to pieces of standard apparatus to facilitate ordering and the classification of records, are given for the standard equipment listed. An interesting feature of the new catalog is the "Instant Index," which appears on a two-page spread, printed on a heavy blue stock and placed in the center of the book. In this index, the 24 groups of equipment described in the catalog are listed in large bold type, and from the name of each group an arrow points to the index notch of the section of the book covering that equipment. Because all the groups thus listed can be noted at a glance, and because two large notches at the bottom of the pages make it easy to open the book to the "Instant Index," finding the information for which one is looking is greatly facilitated.