Clutch Vs Clutchless Piston

[KingRoach]

Hi all.

 

I have a question: I think I understand what a clutchless piston filler is. The piston is operated by a threaded helix. You turn it to push the piston up or down, or keep turning the same helix beyond its stop point to disassemble the piston/pen.

 

What is a clutch on a piston filler? I haven't been able to find information.

 

I am asking also because I have a piston filler that I intend to disassemble and it does something that makes me think it might be a clutch type, but I would like to know what that is first.

 

Best regards

[hari317]

There is no clutch in the conventional sense. This terminology is arbitrary. I have no idea where it originated.

 

Any piston filler can be understood as a nut bolt arrangement. You arrest rotation of one and rotate the other, you get rotary to linear motion.

 

Conventionally, the piston shaft runs straight up and down the barrel. Its rotation is prevented by an anti rotation mechanism. There exist several ways to implement this rotation prevention.

 

In very cheap piston fillers, the mechanical anti rotation feature is simply omitted. Now how does rotary to linear motion transformation take place then? The friction between the barrel walls and piston seal provides this function. Thus such piston fillers cannot operate with very low friction. So they never are as smooth or refined as the Pelikan mechanism for example. There are some advantages like inherent overload protection, simple assembly disassembly, very cheap to manufacture.

 

You risk cracking the knob snout if you use the method of unscrewing beyond the stop method to take apart these fillers.

 

HTH.