Idler that engages/disengages w/ direction change
Idler that engages/disengages w/ direction change
(OP)
Looking for a mechanism to engage/disengage a gear train when drive gear direction changes. Scale is too small for a sprag clutch.
We already have one candidate idea to throw an idler in/out axially with a helical gear. We would also like to find a way to kick an idler gear in/out in-plane with gear rotation.
We already have one candidate idea to throw an idler in/out axially with a helical gear. We would also like to find a way to kick an idler gear in/out in-plane with gear rotation.





RE: Idler that engages/disengages w/ direction change
Won't the use of one lock the rotation of the gear train when the direction is reversed?
Ron Volmershausen
Brunkerville Engineering
Newcastle Australia
http://www.aussieweb.com.au/email.aspx?id=1194181
RE: Idler that engages/disengages w/ direction change
The root issue is that there are two separate gear trains with one prime mover. Need to engage train #1 when driving gear goes CW, and drive #2 when driving gear goes CCW.
RE: Idler that engages/disengages w/ direction change
Posting a drawing of what you propose would help us to help you.
Ron Volmershausen
Brunkerville Engineering
Newcastle Australia
http://www.aussieweb.com.au/email.aspx?id=1194181
RE: Idler that engages/disengages w/ direction change
Do not expect long life from such an arrangement.
Mike Halloran
Pembroke Pines, FL, USA
RE: Idler that engages/disengages w/ direction change
A sprag clutch is probably the most compact device available for a "freewheel" application. So if it does not fit, I don't know what other device might, including roller clutches or ratchets.
If you have some axial space, you may consider a spring-wrap clutch:
Hope that helps.
Terry
RE: Idler that engages/disengages w/ direction change
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Russell Giuliano
RE: Idler that engages/disengages w/ direction change
It sounds like MikeHollaran is describing the reversing mechanism on a VCR drive, which you can kind of see here: http://www.repairfaq.org/sam/idler.gif. VCRs needed to engage /disengage different gear trains depending on direction because the tape had to be pulled from one reel or the other during FFW or REV.