Crocodile roller shutter style garage door

[Harry Bloomfield]

I have the same unit they keep advertising on TV by that builder type bloke, but it is not a Crocodile supplied unit, though the identical electrical/mechanicals.

Today it opened further than it is supposed to do, jammed itself on the roll and the motor kept running and seems to have done itself some internal damage. I managed to release it/unwind it and the door shot down to the fully closed position. Motor makes a noise, when pressing the open button, but the door hardly moves as if something on the drive has stripped.

So I'm looking for some information on the internals of the drive system. The spindle is around 4.5" diameter and includes the motor and obviously must have some sort of concentric gear drive, which I suspect is the issue.

[Harry Bloomfield]

The manual open/close drive also does nothing at all, no resistance to turning the manual drive rod at all.

[Jeff Layman]

Have you tried contacting the manufacturer? They /might/ have spares available.

[Brian Reay]

When we had ours installed, we looked at several suppliers. The brochures, while superficially different, certainly seemed to be offering the same door, perhaps with a different colour/style control box.

That seems the wrong way around. Ours is on the roll when open and unwound when closed.

I suspect the gears will be plastic (maybe nylon). If you are lucky, it could be that something has come loose and 'jumped' out of engagement.

I'd not like to have to lift down the door assembly- ours (a double width one), looks bl**dy heavy. It may be worth getting in the person who installed it.

[tabbypurr]

It took 2 of us to do a single roller shutter so I expect you'll need 2 or 3.

NT

[nothanks]

When I had to fix one of mine last year I found that the motor/gearbox assemblies were easily available on the web (I managed to fix mine so didn't need to buy a replacement) - I think they're called tube motors. Mine have a couple of internal adjustable limit switches.

[Brian Gaff]

Probably failure of that that caused the initial fault as normally a limit switch would stop the motor. Brian

[Steve Walker]

Any decent system would have a limit switch to stop the motor at the correct point and a second one if it passed that, with the second one not allowing return and needing manual intervention - thus revealing the fault.

SteveW

[Harry Bloomfield]

[e-mail] explained on 15/05/2019 :

I delved into it today and all the drive cogs are steel and I found the problem...

It drives via a shaft around 3/8" diameter, but the shaft is machined with a deliberate weak point, where it is reduced in diameter to around

1/16" intended to sheer if it is overloaded. I suspect the 1/16th was less than intended diameter, hence the reason it snapped. The manual crank handle works via the same shaft, so no possibility to even operate it manually. I have tracked down a new replacement unit for £60 delivered, from a Norwich company, so in the interests of expediency I have ordered one from them. Which is cheap for what it is - tube motor, gearbox and limit system. They are quite a clever and very compact design. They extend only a couple of feet inside the barrel, the tube that the door winds on to and off. The motor body rotates with the tube/barrel so is fed via a clever slip ring system.

I have in mind to repair the old one, to keep on the shelf as a spare. Maybe machine some steel tube to fit over the shaft break, drill and pin.

[Harry Bloomfield]

[e-mail] has brought this to us :

Correct, they come in various power outputs and votages, depending on the use they are intended for, with open and close limits.