Extendable / Telescoping Staff Lockout Mechanism

[Elementor5x5]

One of my dream projects for years has been to make a staff (Star Wars Light Staff, Robin's Bo Staff, Predator's Staff) that can actually extend and collapse. Obviously, the extension would be by spring force and/or gravity and/or momentum and the collapse would be entirely manual. What I have been unable to figure out is a good mechanism for locking out the inner sliding pieces once they reach full extension. A typical telescoping baton accomplishes this by having the inner sliding piece having a flared edge at the bottom that catches on the tapered end of the "stationary" piece. This is how all of those toy lightsabers we had growing up work. My problem with this is that it renders the piece useless to support a load along the axis of the staff. Meaning I can never lean on it or pretty much push on anything with the tip. A common way I've seen to overcome this is the "push button" release that you would see typically on tent poles where the sliding piece has a spring loaded stop that extends radially out through a hole in the "stationary" piece once extended. The problem I have with this solution is that now I have to figure out a way to prevent the pieces from rotating with respect to each other so that the button always lines up with the hole. Also, this introduces a lot of :wobble: in the sliding piece as its only held in place at the one point and by the edge of the stationary piece. I'm looking for a way to lock out the sliding piece in the extended position, but still allows for some rotation between the pieces. Any suggestions would be greatly appreciated.

 

[Elementor5x5]

Bump back to the top

 

[Talisen]

Linear actuator - I have a couple of these small devices, about the size of a AA battery that have a peg that extends and retracts with an electrical charge. You could use that to do something similar to that tent pole idea, with a small switch or button on the hilt it would retract to allow the pole to be gravity/freehand returned (and could also be used to hold the pole in)


https://en.wikipedia.org/wiki/Linear_actuator

 

[Elementor5x5]

Good idea Talisen, but I think I would run into the same problem, in that I have to constrain the inner tube from rotating with respect to the outer tube somehow to make sure the pins and holes always line up.

 

[zapwizard]

It sounds like you want something that automatically engages. Otherwise you could use the rotational friction joints which are used on Tripods. You can buy these joints commercially.
They do make internal cam activated locking mechanisms.

 

[Elementor5x5]

It sounds like you want something that automatically engages.

Right, I would prefer something that automatically locks out without having to tighten down any external levers/rotational parts.

I will have to do some more research on this internal cam mechanisms. Is there a commercial name that would be easier to search for them on Grainger/McMasterCarr?

 

[zapwizard]

I haven't seen any of the internal cam models available as stock items. You may have to find some pole and modify it after the fact.
Commercially, as joints, I have only seen the latch and twist-lock versions. They are sold one sites that sell carbon fiber and aluminum telescoping rods.
I only have ever messed with the external lever lock models. (For work, not props)

Most than likely you would have to design your own mechanism and get it 3D printed.

 

[Sean]

What about the actuators engaging an internal two sided break against the outer tube it is in? like a car break but in reverse.