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Author Topic: Brenkert History - Robert Sprague Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-20-2014 12:32 PM                     Steve... Yes... I agree that timing belt system would be fine if you're rebuilding a Chevy Chevette or a Kia Sportage. There is no timing belt drive in the drag car I posted above. It is all geared and my friend Don said it will always be geared and so are all the other engines in the other drag cars they race. Enjoy your timing belts my friend! Mark  |  IP: Logged Steve Matz Jedi Master Film Handler Posts: 672 From: Billings, Montana, USA Registered: Sep 2003 posted 08-20-2014 02:15 PM                     quote: James Westbrook This thread was driven off course as quick as those race cars launch when the light turns green... I agree; so were going to bring this Thread back to BRENKERT and talk about their well engineered Intermittent... (Mark will go to his Grave hating Gilmer Belt Systems) THE BRENKERT BX SERIES INTERMITTENT The precision intermittent in the Brenkert BX80,BX60,BX40 and BX100(RCA)is the most vital part of any projector mechanism and is commonly and correctly termed "The heart of the mechanism" The accuracy of engineering and design,and the precision of MFG of this unit govern the original quality of projection,length of service,and up-keep costs.The importance of good engineering in it's design and the adherence to close tolerances in it's MFG can be realized quickly when one considers the function performed by this unit ... The intermittent must move the film a distance of one frame,or approximately 3/4 inch in 1/96th of a second.this means that the film moved by the intermittent has an average speed of 360FPM compared with a film speed of 90FPM in other parts of the mechanism.However,the intermittent must start moving the film from complete rest and return it to a state of complete rest after it has been moved a distance of one frame.To accomplish this in 1/96th of a second,the film speed must reach a maximum velocity of almost 900FPM in 1/200th of a second... Each succeeding frame in the film moved by the intermittent must occupy exactly the same relative position in the film aperature. Any variation in the location of succeeding frames will show up as unsteady projection on the Screen. As an example,a variation of just .001 thousandth of an inch in the location of succeeding frames in the film aperature with a projected picture width of 20Feet Wide will result in the picture jumping or weaving approximately 1/4 inch. High quality projection over a long period of time therefore depends on a high degree of precision and accuracy in MFG of the parts making up this unit, and the design must be such that this accuracy is constantly maintained... The Brenkert Starwheel,Cam and Cam Pin are of Large Diameter with long Bronze bearing surfaces; The use of large parts facilitates greater accuracy in MFG and provides larger wearing surfaces,which in turn result in greater accuracy of operation and longer wear... The intermittent cam is driven by an external gear fitted to its mating gear with absolutely no backlash; the index pin on the cam is fitted with a hardened steel roller so as to eliminate the possibility of wear and development of flat spots. Each moving part in the intermittent is made of hardened steel, ground and fitted together so precisely that Specially-Designed factory guages are neccessary for making measurements and checking the microscopic tolerances adhered to ... The Star Wheel Shaft in the Brenkert intermittent is 6 and 5/8" long and 7/16" in diameter. It is supported by 2 long Bronze Bushings,one close to the Star Wheel and the other close to the Film Sprocket. The sprocket and star wheel, there-fore, are both held rigidly and accurately in position, resulting in perfect Film Motion and Quiet Operation.Because of the large dimensions of this Shaft and it's 2 Bronze Bushings, wear is negligible and the original accuracy built into this unit is maintained over an extremely long period of time ... Bronze Bushings can be MFGerd much more accurately and will last considerably longer than a cast iron bearing of the same length and bore.The brilliant engineering used in the design of the BX Series Projector mechanism lends itself to the use of Bronze Bearings in the intermittent unit,because of the abundance of filtered oil flowing continously over all it's parts, thoroughly lubricating them and maintaining them at a low temperature.With out this type of lubrication, Bronze Bushings are not practical in an intermittent because the heat generated and held by the oil confined in the intermittent case would result in uneven expansion between the Bronze Bushings and Steel Shafts,which in-turn would result in rapid wear and probable bindups ... An exclusive feature of this intermittent is the method used for attaching the intermittent sprocket. The sprocket can be removed for Reversal or Replacement in less than one minute. It is not neccessary to remove the intermittent unit from the projector or dismantle it to replace the Sprocket.This means quick,safe, and inexpensive(?) Sprocket Replacement for maintaining the High-Quality Projection Standards inherent in this Projector Mechanism. The complete Intermittent Mechanism(P.N. X-3107C) can be removed and replaced as a complete unit easily,quickly and safely in lesstime than is required for the running of an average reel of Film ...(Remember this was engineered in the 1930's)  |  IP: Logged Steve Matz Jedi Master Film Handler Posts: 672 From: Billings, Montana, USA Registered: Sep 2003 posted 08-21-2014 05:21 PM                     The RCA 100(BX-100) Head looks almost out of place with the More modern SH and Lamphouse. I don't remember ever seeing a Century Pedestal being that Color...  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-21-2014 06:50 PM                     Actually it was the RCA 9030 or the 9050 that was typically sold with any Brenkert. It is one or the other that is in your picture. Those were the only two sound reproducers RCA manufactured during that time period. The 1040 and later 1050 were long out of production by then. The 9050 had the advantage of driving the projector mechanism from the lower sound head sprocket rather than the upper. This reduced flutter somewhat as Brenkert's were a fairly heavy load on the gear box. Mark  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-22-2014 02:08 PM                     The eight point star was also found on the PrevostP16/Favorite16B  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 08-23-2014 07:21 AM                     Horston projector...  |  IP: Logged

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