Re: ATM electric clutches - normally engaged?

[Andy Saulietis <iss@pvtnetworks.net>]

Greg G writes,

>Has anyone run across any electric clutches which are normally engaged, but
>will freewheel when power is applied? (preferably 12 volts) Holding torque
>needs are moderate. Enough to keep a somewhat out of balance large dob from
>being easily moved. (through an ~12:1 reduction roller drive)
>
>All the the suppliers I've found only have clutches which engage when power
>is applied... Since the clutches will be engaged 95% of the time, they'd be
>a hogging power needlessly.

I've made electric clutches that use power only while
being moved from one position to the other. A small gearmotor is
used to move screw driven lever which engages/disengages the
clutch, sort of like the throwout lever on an automotive
clutch. If the lever ratio is slow and controllable, the
friction of the clutch can be regulated. Microswitches can be used
to limit the travel as well.



 
Andy Saulietis
ISS Enterprises
39 Silver Fox Trail
Mayhill NM 88339
505-687-3067 voice
505-687-3021 fax, call voice or e-mail to set up
e-mail: iss@pvtnetworks.net