I have a problem with the Elf RM! that I got of Dave, the top sprocket is not turning and when it does its very intermittent, my knowledge of 16mm projectors you can put on the back of a stamp and still have room for name and address so im hoping that somebody can give me some help, to Dave credit he has said that if I send the projector back to him he would sort it out but with carriage charges it works out expensive and if its a 5 minute job that somebody can help me here it would save a lot of time.

Well done Dave and now over to our 16mm experts!....😊😊

i know this may sound silly but is the screw in tight. i had one once where it kept looseing its top loop. it appeared ok but the top sprocket was intermitently slipping causing it to loose its loop.a tghtening of the screw solved the problem.

Hello Paul

I have checked the screw and it is well and truly tight, when I put a screwdriver on it it turned the sprocket.
Here is a picture inside
The sprocket is where the black belt and cogged belt meet.

There doesn't appear to be much of a wrap angle with that toothed belt and gear pulley Dave due to the nature of the toothed belts designed pathway.

Could it be possible that the toothed belt has insufficient tension around the sprocket geared pulley to ensure it remains "timed" throughout?

In other words could the belt be jumping teeth on the geared pulley at times?

Maybe by observing all movements with the rear cover removed you may see more of what may be happening here.

Is the toothed timing belt only for driving the rear arm?
Does the sprocket pulleys and gears get driven directly from the worm gear on the end of the motor shaft?

Without knowing this machine, it isn't easy to see everything just from this one picture here for me sorry.

Hello Andrew

Looking inside, when I turn the projector to forward the belts turn and the pulley turns but the sprocket doesn't, can anyone tell me if their is any sort of clutch mechanism inside where the belts meet that turns the sprocket ?

Dave

Good point Dave and for that to be correctly answered, we need to hear back from some guys here who know this machine intimately.

Here's hoping...

The good news Dave, is it doesn't appear to be too difficult to remove this sprocket shaft assembly to see if the sprocket is connected to the shaft tightly given that you say everything else turns as it should.

It may use a sunken grub screw for example used to fix to the shaft. These can often work loose over the years and unbrako types should always be fitted with the knurled base to prevent this.

I'd be most surprised if there were a clutch fitted to either sprocket.
It is the one place you really never want or need a clutch to be fitted as this would only ever cause buckling or sprocket damage to the film if the clutch were ever to be required or be activated.

Also looking at your front photograph of the projector, the sprocket wheel itself,
( just the component with the teeth on it) appears to be a separate replaceable component like the Super 8mm Elmo ones often are.

If it is, this must have some kind of cut out or key way machined into it at its hub so it stays in time with the turning driven shaft and pulleys.
By removing the cross headed screw, you may be able to quickly and easily remove this component to check for any wear or misalignment etc with the component at its inner hole that it connects with either the shaft or the clamping components surrounding it.

Hello Andrew

I have just emailed Dave Guest and asked him if he knows if it has a clutch, it is easy to take off by the looks its just a screw that you undo to remove the pulley but I don't know what is inside the pulley and I don't want 1001 springs etc falling out, I know at the moment I don't have much to loose but I don't want to make it worse than what it is.

I could really do with a Elf expert to give me some help if their is anyone here.

You are correct Dave, you do really need an Elf expert ideally.
What I will say however, is I very much doubt you could possibly find yourself lumbered with flying springs, washers etc by undoing that cross headed screw that clamps the sprocket teeth wheel together.

I doubt there is much at all behind it, except some recessed machined components that allow the sprocket wheel to remain clamped and firmly in position.

Best of luck anyhow Dave and here's hoping an expert in the ELF field, comes along very soon for you.

I took the plunge and took the pulley off and it does seem to be a clutch assy heres a couple of pics

Get some better close ups David, there is only a couple of ways the drive could work, positive drive with a drive dog or locked in gearing or friction. I notice you have a toothed gear on the inner and a plain pulley on the outer, what does that screw down the centre column do ?, because the plain pulley clearly has a locking screw fixing it to the shaft.

that was good timing David, the pin on that arm in probably warn on the top edge, and not locking in good on those drilled holes around the mating part. Do the top of the pins look round to you ?.

But this is the back of the sprocket shaft Dave, where it takes it's drive from the motor and also one of the sections along this shaft where you said everything was turning as it should earlier on this morning??

that clutch is surely only there to protect the rewind arm once this pulley connects to the round plain black drive belt?
Separate altogether to the drive to your sprocket

it looks from the photo that what drives your actual sprocket is the worm gear from the motor and the large brown spur gear off it, if i am seeing things correctly from your early photo's here.

I have just been investigating more, when the machine is in forward the cogged belt turns nicely as seen in the photo, this cogged belt is the main belt that turns the take up spool BUT the pulley that is connected with the black belt and is connected with the cogged belt stays still and its this pulley that turns the top sprocket, so the clutch is definitely slipping.

The black belt is connected to the supply spool arm. It provides a slight drag to stop the spool overrunning in forward mode. But, when in rewind mode, it drives on full power. There does seem to be a problem with the clutch.
What happens when the rewind lever is operated?

When the rewind lever is in the UP position(for rewind) the top sprocket works fine but when the rewind arm is done so in thread mode the top sprocket doesn't work.
Dave Guest is going to send these parts so hopefully it will cure the problem

Maurice, can you tell me from the picture below if the small pin is in the right position, should it be leaning on the shaft

I am very sorry, but actual servicing of my fleet is carried out professionally so I never venture inside a projector!
As was mentioned, all our beauties are probably close on 50 years old now.
I am very fortunate to have a superb gentleman who keeps all mine running, including new worm gears for my many Bell & Howells.

I would just like to say a BIG THANK YOU for everyone that helped me with my problem, I think it is now sorted and Dave is very kindly sending me the parts to fit so all going well it will be up and running very soon.

Hey that's brilliant news Dave and proves Paul in his initial posting, was absolutely bang on.

Well done once again Dave and all who helped him find and rectify his issue.