Film-Tech Forum ARCHIVE: Designs for accumulator

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Posted by Michael Voiland (Member # 5386) on 10-22-2009, 12:52 AM:

Does anyone have any good designs for a interlock film accumulator. If so could you post it.

Posted by Monte L Fullmer (Member # 2797) on 10-22-2009, 01:04 AM:

Kelmar has a good accumulator being of two rollers spaced three feet apart and an arm with a roller at the end along with another roller at the pivot point. The weight of the arm would keep the film taut between the two rollers.

STRONG has an accumulator that looks like an enlarged version of the "yo-yo" roller assembly on their platters. It has three rollers on the lower half and 5 rollers on top so the film weaves inbetween these rollers. The lower roller assembly would travel up between two rods and that lower assembly had enough weight to keep the film taut.

We had a home-made accumulator system composed, once again of two side rollers spaced about 3 feet apart with a roller on a bracket that is weighted in the middle and also suspended by a chain connected to the ceiling. the weight kept the film taut between the two rollers.

But, the slickest way to do accumulating is with using the Christie AW3 platter's takeup arm as the accumulator. If you have two AW3's close enough together and in direct sight of one another, along with extra rollers on top of the tower, this works extremely well and you don't have rollers all over the ceiling, nor any external accumulators needed.

-Monte

Posted by Michael Voiland (Member # 5386) on 10-22-2009, 09:23 AM:

We have 2 simplex 35's with out sync motors and strong platters. I am looking for interlock them who ever was their before had like an 5 foot wooden board that would hang off another board on the wall. Thanks for the info I think we have a strong one for one of our other projectors.

Posted by Randy Stankey (Member # 64) on 10-22-2009, 10:02 AM:

One of the theaters I used to work at had an interesting arrangement for a film accumulator. It was the Cinemark 8-plex in Summerville, SC, just outside of Charleston.

They took a Strong accumulator like Monte mentions and mounted it to a piece of heavy plywood. Then they took an old wheel rim from a truck or something like that and welded a piece of 2 inch iron pipe to it so as to make a vertical post. The wheel rim at the bottom was a weighted base. The accumulator on the board was fastened to the upright post with some U-bolts.

You could use a two-wheeled dolly and move the accumulator anywhere you needed it. The only caveat would be that you have to be careful to align the accumulator with the film path or you could get scratches or the film could jump the track.

Posted by Demetris Thoupis (Member # 833) on 10-22-2009, 01:08 PM:

One very easy interlock accumulator is this

You can use three wall rollers. Place two rollers in a straight path about 50 cm appart(approximately 2 feet) and take one roller appart and place two light metal plates vertical to work as counterweights on the roller. You will need to place something to keep the rollers' bearings operating and not have the roller rubbing without rolling against the film. In any case you can place two rollers on a straight line in all your paths and have one or two counterweighted rollers with plates since you can easily move them.

Demetris

Posted by Ken McFall (Member # 845) on 10-22-2009, 01:38 PM:

This was the way I did it as we had a cable tray run the length of the projection room. Not the best picture but all I have now

I used a double roller drop to reduce the amount of arm travel. For a 3 screen run I had two of these...

The platters, Kinoton st 200, were fitted with two addional rollers to send the film to the cable tray and on to the next projector.

The film cleaner with Film Guard was simply hooked onto the platter column.

Hope this is of interest.

Regards.

Posted by Mark Gulbrandsen (Member # 72) on 10-22-2009, 02:58 PM:

I prefer the Speco Accumulators. They are heavy and don't move around in operation but easily movable between screens or locations.

Mark

Posted by Monte L Fullmer (Member # 2797) on 10-22-2009, 04:48 PM:

quote: Michael Voiland
We have 2 simplex 35's with out sync motors and strong platters

If they're induction motors, it will be tough to do interlock then since the motors are not running at the same speed being that induction motors are more sensitive to line voltage than line frequency as with sync motors.

You will then have to figure out which motor runs the slowest and maybe put a variac on the faster motor to slow it down to the slowest motor. Otherwise, you're gonna have BIG problems, esp in the middle of your show travel.

I saw one triplex that had Centurys with induction motors. His homemade accumulator was a good dozen rollers - half which were on a slider assembly where the film was like in a film roller bin - going all through the rollers in a vertical fashion like the STRONG accumulator.

When he would do his interlock, he'd lace through all the rollers and when show begins, he'd watch the lower rollers on this contraption. If one roller began to rise to almost halfway point, he would flip the film off that roller and let the next roller continue on until it began to raise .. an so forth.

It was a very nerve wracking experience since the operator had to watch this all the time.

-Monte

Posted by John Walsh (Member # 168) on 10-22-2009, 05:51 PM:

The Neumade accumulator has a switch to shut down the automation if there's a too much tension at start.

Posted by Steve Guttag (Member # 268) on 10-22-2009, 09:08 PM:

Monte...all of my initial interlocks were with async motors. Most of the projectors with these motors also have a motor brake...an appropriately sized foam rubber square (from packing material that might be laying about) shoved between the brake level and the case would cause the brake to apply enough pressure to the "faster" motor to effectively event them out.

Steve

Posted by Michael Voiland (Member # 5386) on 10-23-2009, 01:37 AM:

We currently have a 2 screen interlock that runs at close to the same speed we start it about halfway down our strong accumulator and it is about 6 inches from the top at the end. I am trying to think of a good way to do a 4 screen interlock for twilight.

Posted by Brad Miller (Member # 2) on 10-23-2009, 01:49 AM:

Thread between those two with the film running in the OTHER direction and start with the accumulator almost at the very top. This way it will drop during the show rather than tighten up to the point it starts tearing things off the walls.