Flexible shaft

Posted by Doctor Robotnik on December 7, 2005, 2:32 pm

I am looking for a flixible shaft able to transmit forces of 4240
in/lbs at 5 rpm. Its for a robot arm, I want it to be strong but not
bulky so that pretty much leaves me with the option of having the
motors not in the arm itself. Gordon McComb this may be up your alley.

Posted by Gordon McComb on December 7, 2005, 2:53 pm

Doctor Robotnik wrote:

>
> I am looking for a flixible shaft able to transmit forces of 4240
> in/lbs at 5 rpm. Its for a robot arm, I want it to be strong but not
> bulky so that pretty much leaves me with the option of having the
> motors not in the arm itself. Gordon McComb this may be up your alley.

Whoa! This is a fairly hefty amount of torque you need to transmit.

You might try starting here. They have a handy comparison chart showing
the max torque for the different diameters of flexible shaft they offer.
Your application exceeds their highest maximums, even for 1/2" cable, by
a factor of more than 10! I don't think the low RPM will make up for the

difference. <g>

http://www.wmberg.com/T05002.html

I wonder if pneumatics or even small hydraulics might not be called for
in an application such as this. Or, going from a flexible shaft to a
more traditional pull shaft. Even 1/8" steel aircraft cable can lift a
lot of pounds...it just can't twist that much torque.

-- Gordon

Posted by Padu on December 7, 2005, 3:32 pm

"Gordon McComb"

> Doctor Robotnik wrote:

>> I am looking for a flixible shaft able to transmit forces of 4240
>> in/lbs at 5 rpm. Its for a robot arm, I want it to be strong but not
>> bulky so that pretty much leaves me with the option of having the
>> motors not in the arm itself. Gordon McComb this may be up your alley.

> Whoa! This is a fairly hefty amount of torque you need to transmit.
> You might try starting here. They have a handy comparison chart showing
> the max torque for the different diameters of flexible shaft they offer.
> Your application exceeds their highest maximums, even for 1/2" cable, by
> a factor of more than 10! I don't think the low RPM will make up for the
> http://www.wmberg.com/T05002.html
> I wonder if pneumatics or even small hydraulics might not be called for
> in an application such as this. Or, going from a flexible shaft to a
> more traditional pull shaft. Even 1/8" steel aircraft cable can lift a
> lot of pounds...it just can't twist that much torque.
> -- Gordon

May I ask what a flexible shaft is and where/how it is applied?

Cheers

Padu

Posted by Doctor Robotnik on December 7, 2005, 4:25 pm

Basically its like a large wire attached to the motor shaft that
rotates as the shaft rotates, it is encashed in a sheath that doesn't
rotate. Its good if you need the power far from the motor, espically if
you may have to make a few bends to get where you need. Dentists drills
use this, some lathes, dremal tools can get one as an attathment option.

Posted by Padu on December 7, 2005, 4:30 pm

"Doctor Robotnik"

> Basically its like a large wire attached to the motor shaft that
> rotates as the shaft rotates, it is encashed in a sheath that doesn't
> rotate. Its good if you need the power far from the motor, espically if
> you may have to make a few bends to get where you need. Dentists drills
> use this, some lathes, dremal tools can get one as an attathment option.

Got it! Thanks

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