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.
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
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.
"Doctor Robotnik"
Got it! Thanks
Maybe consider using a universal joint rather than a flexible shaft? Something like this:
Best,
- Joe
,------------------------------------------------------------------. | Joseph J. Strout Check out the Mac Web Directory: | | snipped-for-privacy@strout.net
It'll be a lot easier if you transmit, say, 8.6 LB-IN at 2500 RPM and gear it down close to the load. The 500:1 gear reduction can be implemented compactly with 2 worm gear stages.
-- Matt
Can you help me find parts to make a 2 stage 500:1 worm gear box?
--Here's a photo of one device that *may* do what you want. There's a pointer to where to get them in the MSC catalog, too.
For that much torque, only expensive ones:
-- Matt
How large would such a system be, I would need a comprressor, and tank. Would that be really noisy as the compressor turned on, and how heavy would a hydrolic system be. I would like this to be able to be on a mobile platform.
You need to read "Robot Evolution", by Mark Rosheim, and see his web site, "
Also, you need the catalogs from Berg and from Stock Drive Products, so you can see what's available in parts.
Flexible shafts are not usually used for such large loads. For numbers like that, you usually have to use solid shafts and universal joints, or gear drives at the output end, or chains, or cables.
John Nagle
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.