Dynapac CM13

[jonnyt]

Hi Guys

Thanks for letting me join.

I have just bought a Dynapac CM13 vibrating plate. It’s an old one and the plate says it’s a winget.

Anyway, just doing some general service bits before trying to start it and ‘be noticed that the pulley on the vibrating drum (bolted to the vibrating plate) is eccentric. Obviously the shaft is weighted to provide the vibration but it seems odd that the pulley should be eccentric (belts will go from tight to loose as it rotates. However it all looks original and there is no wear that I can see on the pulley or the shaft - it is so bad that it would be obvious.

Can anyone confirm whether the pulley is meant to be eccentric or whether I need to change it.

Photos attached in case it helps - (you can see the witness marks from the washer are off centre to the pulley in the 2nd)

Thank you!

 

[V8Druid]

Hi Guys

Thanks for letting me join.

I have just bought a Dynapac CM13 vibrating plate. It’s an old one and the plate says it’s a winget.

Anyway, just doing some general service bits before trying to start it and ‘be noticed that the pulley on the vibrating drum (bolted to the vibrating plate) is eccentric. Obviously the shaft is weighted to provide the vibration but it seems odd that the pulley should be eccentric (belts will go from tight to loose as it rotates. However it all looks original and there is no wear that I can see on the pulley or the shaft - it is so bad that it would be obvious.

Can anyone confirm whether the pulley is meant to be eccentric or whether I need to change it.

Photos attached in case it helps - (you can see the witness marks from the washer are off centre to the pulley in the 2nd)

Thank you!

is it just the washer that's eccentric ? ...

 

[Smiffy]

is it just the washer that's eccentric ? ...

No I think it's most the forum

 

[V8Druid]

No I think it's most the forum

very good .....
just wondered if the pulley itself is the same, 'cos as said, the belts'd go from tensioned to loose in half a rotation and possibly stop driving, if loose enough to not make a full contact.... the pulley boss certainly looks to be eccentric in that 2nd pic and can't see HTF it'd function

 

[T whiting]

I'd try and fire it up it'll either become obvious how it works or throw it's belt across the workshop

 

[Shovelhands]

Just spin it by hand with something held close to the pulley edge, just to see if it really is an eccentric pulley or just an illusion, could be the casting not true but is machined correctly?

 

[jonnyt]

Thanks guys. Only just seen these replies. Had a dti on it and the shaft runs true. The pulley is eccentric by at least 5mm at a guess. Nothing worn - very odd!!

I’ll try firing it up and seeing what happens but I don’t hold out much hope!

 

[Mick-the-fitter]

That’s an old villiers C15 is it not?

 

[V8Druid]

That’s an old villiers C15 is it not?

does have that 'Villiers' look about it

 

[jonnyt]

F15.29.68 is the model number.

 

[jonnyt]

Always hate it when these threads never have an answer!!

Just spoken to an old Dynapac tech. The pulley is intended and is deliberately eccentric to allow the belts to remain in tension when the vibrating plate moves up and down.

Tensioning process is to have a little bit (just a little bit) of tension when the pulley is closest, I.E. when the belt is at its shortest.

His words were, ‘you’ll be amazed how it just works and the belts remain in tension - best machine we ever made’ !!

Thanks again all.