Help with Design on Motorized Tool Dolly

[goodblasson]

Hello Guys, this is my first post so go easy on me. I am working on a project at work, I have to design a motorized cart that can move up to a 5,000lb load. The cart is 72" long, 27" wide, and 30" tall, it has arms that hold rollers which a 8" diameter tool sits on the rollers. The cart has to move up to 3mph and the 4 wheels are 8" diameter and made of steel and roll on inverted angle iron(like a train track). Anyhow, the customer wants to see a DC motor used and have the power supply onboard. It has to have some kind of control to start slow and gain speed up to 3mph and slow down to stop. My problem is that I can not find a DC motor and gear setup to propel the cart at 3mph and handle the load. Can anyone give me any input or suggestions please? I was thinking of buying a motorized pallet jack and modify it so that I can connect it to my cart for propulsion. But obviously thats the cheap and ugly way out of my problem. I am including a picture of a cart another customer uses, but they will not give me any details to the build so I am on my own....

 

[Ross0684]

Bill
Fair comment, but all wheels are flanged and normally run on crane rail each side or can even be set up to run on the inside of tapered flange channels- this acts as guide means.
I accept that some cranes have lateral shafts with driven wheel each end (ie each side) of crane, but smaller units can have but one driven wheel-all depends on load and duty cycle/speed etc.
Ross

 

[tygerdawg]

goodblasson

You should investigate SEW Eurodrive gearmotors. I think they still make units with DC motors of sufficient power. A great resource from them is the German-made English Language Engineering Manuals which have calculation samples for this kind of thing. Very rigorous, but you will have to dig through the German English Language site to find them. SEW also had a gearmotor sizing program that was plug & chug...it may not exactly solve this design problem, but give you insight. I think you must request this through the Sales channel now so that they can chase you down and try to sell you something.

I can't say for certain, but perhaps the other manufacturers out there (Falk, Nord, Dodge, etc) have free manuals with engineering calculation sections that may be of use.

If you don't understand the math behind dynamics, then you should websearch & download the Smart Motion Cheat Sheet. Or turn this design over to a qualified mechanical engineer. You're dealing with some serious stuff here.

Also, I vaguely recall that Machinery's Handbook has some data & design guidelines on steel-on-steel rolling parameters.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com