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Topic: Simplex Hi Speed Intermittents.

Randy Bowden
Expert Film Handler

Posts: 146
From: Portland, OR, USA
Registered: Aug 2000

posted 09-24-2001 01:02 PM

Could someone please explain to me the practical aplications
for the Simplex Hi Speed intermittent. What were these things used for? I'm assuming they run at a higher frame rate, anyone know what that might be? I have rebuilt hundreds of Simplex intermittens and a couple of these things so far and am wondering if I should continue to convert them to a standard set up or keep with the high speed parts. Are these things obsolete. A little help please.

Thanks
Randy

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 09-24-2001 01:10 PM

The "high speed" or "drive-in" intermittents pulled the film into position faster, allowing the use of a smaller shutter blade to put more light on the screen. A typical "Geneva" starwheel intermittent takes 90-degrees of rotation (4:1 intermittent)to pull the film into position, whereas a "high speed" movement only takes about 72-degrees (5:1 intermittent). The downside is the additional mechanical components, increased noise, and increased stress on the sprocket teeth and film perforations due to the higher accelerations. The increased strength and durability of today's polyester film base helps reduce the risk of perforation damage.

I suggest keeping the high speed linkage, and using those intermittents for applications that need the increased light (drive-ins and really large indoor screens).

Kodak was recently granted a patent on a new "Geneva mechanism and motion picture projector using same" (US Patent 6,183,087 , February 6, 2001 ) that modifies the starwheel and cam to achieve a much faster pulldown WITHOUT additional linkages:

Kodak Patent on New Intermittent

This Kodak invention will allow much greater light efficiency with a simple intermittent mechanism. The extra efficiency can be used to increase screen luminance, or allow the use of a three-blade shutter on larger screens, greatly reducing flicker. The Kodak prototype starwheel and cam were easily retrofit into existing intermittents like the Century.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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Randy Bowden
Expert Film Handler

Posts: 146
From: Portland, OR, USA
Registered: Aug 2000

posted 09-24-2001 01:39 PM

John.
Thanks for the Reply. I will go ahead and do the rebuild with the High speed parts. These intermittents could definitely come in handy for the Drive in theatres that we service.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 09-24-2001 05:11 PM

Randy, the high speeds are quite good. Their main problem was back when everyone was still using cement splices. The acceleration is so fast(5 to1) that it would pull the splices apart. Many were converted to regular speed d(3 to 1) due to this problem. Later when tape splicers hit the market it was really too late to save the HS pulldown intermittent. I have done quite a few projection jobs with high speed machines that I had at one time. Also I notice a definate improvement in on screen steadiness and apparent sharpness in the projected image. The best place to see this is in the rolling titles at the end of a feature. They appear unusually clear for some unknown phenomona. Parts are no longer available and you should use a low inertia alumnium sprocket to prevent excess weat to the moving parts. With the advent of polyestar film, the HS movement should really become compnplace today. Perhasp with Kodaks new designs that can be retrofitted into a Century easily it will happen. But I'm sure Kodak will want a premium for the parts too.
Mark @ GTS

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 09-24-2001 08:02 PM

Mark, you were right about them pulling cement splices apart. They also devoured single-sided tape splices, too!

Paul

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Josh Jones
Redhat

Posts: 1207
From: Plano, TX
Registered: Apr 2000

posted 09-24-2001 09:02 PM

I received info today on the brenkert bx90 telecine projector from our Mr. Sprague friend. It contained no shutter, no shutter compensator, but did contain a high speed modified movement, which did appear to be self contained and enclosed. more details when I get a chance to read the 25 pages or so of goodies I got in the mail today.

Josh

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Christopher Seo
Jedi Master Film Handler

Posts: 530
From: Los Angeles, CA
Registered: Jun 99

posted 09-25-2001 06:22 AM

Randy,

For a handful of old topics on this subject just do a search for "high speed pulldown".

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Robert Throop
Master Film Handler

Posts: 412
From: Vernon, NY USA
Registered: Jun 99

posted 12-03-2003 01:30 PM

Last week I replaced an intermittent in a Simplex XL. After changing the movement there was a travel ghost that could not be adjusted out. We realized that this was a high speed intermittent and replacing the shutter blade cured the problem.
This projector is installed in an art museum and was one of a matched pair of XL's installed in 1960. This was the original intermittent. This was a non critical installation and originally had Peerless Magnarcs. Now there's a Xenex 2 and a platter. I'm baffled as to why the hi speed movement was purchased. The other machine is long gone so we can't look at that intermittent.
Are Hi Speed parts still available?
I've been in this business since 1965 and this is the first one I've come across.

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Jason Burroughs
Jedi Master Film Handler

Posts: 654
From: Allen, TX
Registered: Jun 99

posted 12-03-2003 02:10 PM

Correct me if I'm wrong, but wouldn't a High-Speed intermittant potentially produce LESS shutter smear than a standard intermittant witht he same shutter in place?

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 12-03-2003 03:08 PM

I think Mr. Throop replaced a high speed (5:1) movement with a standard (4:1) movement, so the shutter blade had to be increased from about 72 degrees to 90 degrees coverage.

Although high speed intermittents usually were used to obtain better light efficiency for drive-ins and really large screens, perhaps the museum needed more light on the screen from the Peerless Magnarc.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-03-2003 07:13 PM

For unexplained reasons I've always noticed far better image definition when projecting with a high speed movement. Sharper, steadier, etc. There is a BIG difference. A high speed movement and the correct shutter blade and the machine will typically run around 70+% light efficiency.

Mark @ CLACO

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Justin West
Master Film Handler

Posts: 271
From: Peoria, IL, USA
Registered: Jul 2001

posted 12-04-2003 04:01 AM

Is there a mark or catalog number ON the intermittent that distinguishes itself as a Hi-Speed variety...just in case I were to come across it in a pile of old projector parts... [Confused]

Thanks!

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-04-2003 08:27 AM

Even without taking it apart its easy to tell a HS movement. grey in color Low INertia Almunium Sprocket...usually, unless someone has replaced it with a steel one which is incorrect. These Low Inertia sprockets are still available from LaVezzi (416DG31 I think). The cam is also mounted to the outboard cover and the end of the cam bushing is visible from the front slightly to the lower left of the sprocket. The flywheel is a bit thicker and has a small taper to one edge of it. It will also have a very low and totally different type of serial number than a regular movement.

Mark @ CLACO

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Randy Bowden
Expert Film Handler

Posts: 146
From: Portland, OR, USA
Registered: Aug 2000

posted 12-04-2003 07:13 PM

Robert,
If you need hi speed parts I do have a few. You could also try wolk for parts, or I could rebuild it for you. The shaft & Gear are different than the standard G-1836 the part # is G-4128 the same starwheel is used, the cam is part # G-4131

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