Need Help with Finding a Mechanism to Connect Two Axles

Hi Everyone!

I have ran into a wall in my design. I need connecting two spinning axles in a vacuum environment. The bottom axle is attached to a motor and the top axle is attached to a moving box. Is there a mechanism that can quickly quickly connect the axles when the axles are aligned? If the axles are perpendicular to the X and Y plane, the only motion available is in the Z direction. There can be no movement of each axle when attaching. After attaching, the axles must rotate together with an extremely high tolerance and be able to disconnect and connect quickly through a Z direction movement.

My solutions right now are but they all have individual problems.

A magnetic connection.

A high precision sensor alignment with a locking mechanism.

Thanks in advanced!
I don't know the details of your arrangement, but:
If the axles are offset (not coaxial), tapered (smooth) cones will allow engagement/disengagement with Z travel. At least 1 of the cones would have some compliance (hard rubber...). I don't know your speed/torque/space available - just a thought.


Insights Author
Gold Member
I have trouble visualizing your geometry. You say top and bottom axles. Do you mean co-axial? A keyway with key is the traditional way to lock two co-axial axles.


Science Advisor
Welcome to PF.
If the axles must lock together in the angular position they first contact, without any rotation, then you should consider two mating tapers such as morse machine tapers. They come in several sizes, male and female for holding or adapting machine tooling. Some male tapers have a tang to prevent rotation that would need to be removed. You could grind a taper on one shaft and ream a socket in the other, or you could buy adaptors. A paper sleeve would increase friction. There is probably no requirement that the tapers be made from steel. Low angle tapers are self locking while wider angle tapers release easily. The critical angle that decides the boundary between self locking and self releasing tapers is the arctangent of the coefficient of friction between the mating surfaces.

Alternatively you could have two disks that align and contact face to face. One would be covered with sandpaper, the other with a coil or peripheral ring of silicon tube that distorts slightly to maintain positive contact with the grit during rotation.

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