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Locking Mechanism reducing load on locking pin

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  1. Apr 1, 2017 #1
    Hi,

    I wanted to make a locking mechanism. The problem was the forces on the actuator (solenoid in this case) where getting too high
    In image 2, the wedge shaped lock plate was exerting too much force on the actuator, which would unlock and could potentially break the actuator. Or I would have needed a very big and strong (more force) actuator.

    In image 1, since the actuator is now perpendicular to any potential force, the actuator does not need to apply a lot of force (except weight of the locking pin/shaft and frictions).
    But most importantly, the locking pin takes all the force. In this case it's perpendicular to the axis of the locking pin, hence no direct axial load on the locking pin, actuator shaft, hence chances of actuator accidentally unlocking or breaking away is less.
    All the bending force will be reacted to by the locking pin which is supported by the linear bearing.
    Of course there is a coupling needed to couple the actuator shaft with the actual lock pin.

    My query is will this work the way it is intended to. It sounds too simple to work.
     

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    Last edited: Apr 1, 2017
  2. jcsd
  3. Apr 1, 2017 #2
    It's a bit hard to picture this without understanding more about what you are trying to lock. It seems you have a shaft that is constrained only to rotate, and you want to use a solenoid actuator to hold this shaft in place... your idea is to have the pin that the solenoid pushes interrupt the rotation, and you think you can avoid or reduce stress on the actuator by changing the orientation of the pin. And you think it will be much better to have the pin parallel to the axis of the rotating shaft instead of perpendicular to it?

    You are right to avoid any torque on the solenoidal actuator, but I'm not convinced that your linear bearing can do this. It would be best if you could have a bearing on both sides of the load and have the pin stick far enough to go through both bearings. If possible, I recommend increasing the radius of the lock-point relative to the rotation axis of the shaft you are locking. This will reduce the force on the locking mechanism considerably.

    PS. Magnetic Braking?
     
  4. Apr 15, 2017 #3
    Looks like what is really important in this problem is the shape of the slot and the shape of the end of the pin. You do not want cam action to develop a forces that tends to unlock the shaft allowing it to rotate. This means that the side of the shaft slot that bears against the locking pin must push across the pin, with no axial component along the pin. Will it work? Sure, it will work provided the shapes are carefully determined, the geometry is carefully maintained by adequate supports and guides, and the materials do not fail.
     
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