Anti-backdrive mechanism

[medo79]

Dear all,
I am looking for light weight mechanism which will connect to the gearbox output. This mechanism will be free to rotate when backdrive torque was applied to the gearbox output without transmitting this movement to the gearbox and the motor. However, it will transmit the movement when driving torque was appling from the motor. I was thinking to use clutch, but the main problem is the weight of clutch because the transmitted torque is around 100N.m. I am looking for a mechanism has a weight less than 0.5kg and working as anti-backdrive without preventing the load from the movement.

 

[DesignerGuy16]

http://www.koyousa.com/brochures/pdfs/cat286ex - Sprag Clutches.pdf

Something like that would work.

James Spisich
Design Engineer, CSWP

 

[medo79]

Dear James,
This is very good clutch, and lightweight. However, it allows the rotation in one direction. The problem that the backdrive movement might be in CW or CCW directions. I want a mechanism of clutch which works when the motion applied from the motor and doesn't work when the motion applied from the output in both clock-wise and counter clock-wise directions.
Best regards,
Mohammed

 

[medo79]

For more detail, I am looking for lightweight clutch which weighs less than 0.5kg which works in both CW and ACW direction. This clutch works only if the torque applied from the input side either in CW or ACW, and doesn't work when torque applied in the output side. This clutch/mechanism will work at low speed (75rpm), and the maximum torque is 150N.m.

 

[DesignerGuy16]

Google up "wrapped spring clutch" and "overrunning clutch".

James Spisich
Design Engineer, CSWP

 

[medo79]

but this is works only in one direction either CW or ACW.

 

[sreid]

A Formsprag Bi-Directional Backstop Clutch.

http://www.warnernet.com/smartcat/sc_app/default.asp?vid=10,10,2,0

 

[medo79]

I am looking for Bi-directional overrunning clutch becuase I don't want to backstop the backdrive action, but I want it overrun it.I mean that the clutch disengages automatically when the driven member rotates faster than the driving member in both CW and ACW with the following specifications:
Maximum torque=150N.m
Continous rated torque=50N.m
maximum working speed=75rpm