Does anyone know what the mechinism is called that is used in a retractable ball point pen?
The type of pen where you push the button down, the pen tip extends. Then when you push the button down again, the pen tip retracts.
There is the little plastic part that spins when you do the pressing, and this is what allows the tip to basically have two resting spots. In and Out.
What i'm trying to do is move a block between 2 positions (approximately .4 inch apart) and hold it in either position for an extended period of time (maybe stay in one position forever)
The only power source I have available is +12 VDC. I thougth that I could use a continuous duty electrical solenoid to move and hold it in the extended position and have a spring return it to the retracted position when I drop power to the solenoid.
The problem is that the solenoid gets too hot when left on for an extended period of time. It does not damage the solenoid, but I cannot use it because of the temperature rise, and I have no means of dissapating the heat. The solenoid manufacturer says that a 60C temperature rise is typical regardless of who's solenoid i use.
I'm thinking that if I know how a ball point pen works, I should be able to integrate the same type of mechanism into my design. That way, I only need to pulse the solenoid to move the block to the farthest position and then pulse the solenoid again to move it back to the original position.
I believe that if done correctly, this will work and also the placement of the block at each position should be very repeatable. I can live with the over-stroke that is seen in the ball point pen mechanism that you see when pressing the button.
Any guidance or a link to a website that explains how this works would be appreciated.
ball point pen type mechanism ??
Re: ball point pen type mechanism ??
