Impulse Drive

[David Tilston]

As proposed in this post:
http://www.fiberglassrv.com/forums/f...tml#post449666

I have acquired the means to make my trailer self propelled. These are the light duty motors, they sell this set for $50. My brother got the much more industrial version for $80.

I at first thought, just put the wheel on the tire of the trailer. That however would be trying to push ~2500 lbs at the same speed as the wheel chair would have gone. This is a bad plan.

I am shooting for torque, not speed.

Now I am looking to replace the wheel with a much smaller diameter splined shaft. Splined to bite into the tire, as it turns, but easy to slide length wise across the tire. I am not sure if I leave the motors in place, or make them stow-able.

[Night Sailor]

You can use them for steering by varying the power to each wheel or by turning them in opposite directions.

I wanted to put a motor drive on my boat trailer. I dry sailed it. It was a 30' boat that weight 3300 lbs. I stored it on the trailer between used. This worked well but was a PITA as I had to push the boat to the hoist and there was a dip in the path which required a lot of muscle. The club would not let me use the fork lift which had a ball on one tine. I opted to bail out of the club instead of going to such extremes. That plus the fact that they charged me for a year I didn't keep the boat there.

[Roy in TO]

What is the RPM's on those Dave?
With the bolt on wheels I see the potential for some gear reduction and modifying a trailer dolly. The hill up from my garage is just a bit too much for me to wrangle a trailer up by hand.

[Raz]

Sounds a little like the Quadractor

http://quadractor.com/index.htm

[David Tilston]

I have never seen the wheel chair this came off, so I am operating on guesses. I have not connected it to 24 VDC yet.

The 7" tires look like they are designed to contact the road, so I have to assume they can get up to a jogging pace.

Using a 1" splined shaft, in the place of the wheels, pushing on the tires of the trailer, I should get a 7 to 1 reduction in speed. Or a slow walking pace, at top speed.

The idea is that the splined shaft would be removable, with the motors mounted permanently. When we arrive at site, drop the tongue jack, with a castor wheel. uncouple the trailer, pound in the spline shafts and drive the trailer to the camp site.

The control system is designed to operate with a fine degree of control, so I think it should be OK to use to drive into my camping spot. Maybe put an umbilical on the controller, so I can see what is around the trailer as it moves.

[Roy in TO]

Originally Posted by David Tilston

I have not connected it to 24 VDC yet.

That would mean dual 12 V batteries then. I wonder how small the batteries could be. They would only be needed for short term use.

[David Tilston]

I currently have two 12VDC batteries on my trailer. For ballast mostly. When one runs low, I connect to the other. For this system, I will run them in series, but still pull off one or the other when camping. I will need a fancy battery switch now. I was close to getting it going last night, but I got distracted. I hope to do it tonight, or this weekend at the latest. I will post a video of the results.

[RogerDat]

What about mounting the rig on a small cart with a ball? Use the existing wheels (or replace with smaller ones) to drive the wheels of the cart? Thinking something along the lines of a push mower or old style reel mower with casters on handle side and driven wheels toward trailer.

Batteries, drive, controls and ball as self contained unit. Someone once described to me a gas version of this used to move boats.

[David Tilston]

Can't use that as an art vehicle at Burning Man. I see a stool where the table would be and the joystick mounted to the inside back wall of the trailer, where the table would be. The back is now the front of a very slow vehicle. With enough solar power, (~2000 W) I should be able to get up to jogging speed.

Besides, where do you put the cart when on the road. The practical application of this system is to never have to back into a camping site again. You could just drive the trailer in.

[Donna D.]

Originally Posted by David Tilston

.... The practical application of this system is to never have to back into a camping site again. You could just drive the trailer in.

But, then you have to back it out to leave. Right?

[David Tilston]

Nope. I see it driving backwards, or think of the back as the front. Much better view that way. So, the tongue should still be pointed towards the entrance of the camping spot. I see no reason to bring the tow vehicle to the trailer, but if you don't want to use the impulse drive to get it to your tow vehicle, then you can just back your tow vehicle up to it.

[David Tilston]

So I got it hooked up to 24 VDC. It works flawlessly. Lots of logic to prevent harsh operation. It slows down before it stops. It wont spin fast. Forward is faster then reverse.

The horn is just a beep.

There are several speeds.

I tried to hold it. Even in the slowest speed, the torque is quite high, as in I could not slow it down at all.

I hope the video works. I got an error. Is there a problem with .MOV files?

No video. I tried several times and got the same error.

[David Tilston]

I took off the wheels. The four hex key bolts just hold the two halfs of the wheels together. the center bolt is what held on the wheel. What was left when I took the wheels off was a 17mm keyed shaft with a threaded hole on the end of the shaft. So I am looking at getting a custom shaft machined that will fit over the keyed shaft and end in a 2" diameter knurled rod. It will be held on with a long bolt into the knurled end to the threaded hole in the end of motor shaft.

Did more testing on the motors.

The wheel chair motor spins at 140 rpm, no load speed. The wheels that came with the motors were 7" diameter. This should have provided a top speed of 257 feet per minute. The custom machined knurled rod will be 2" diameter. This will provide a 3.5 to 1 reduction in top speed to 73 feet per minute. I figure the motors were intended to push a 300 lb person on a 250 lb chair for a total of 550 lbs. The 3.5 reduction in speed should give approximately a 3.5 multiple of weight capacity or 1925 lb. The trailer is about 2200 lb fully loaded, so pretty close. I am guessing that with two group 24 gel cells, he could go for two to four hours. So the trailer could move 1.6 to 3.3 miles on its own. Further if I use some of the extra gel cells I have.

[frankcfx]

The motors sound like a good way to fab a trailer mover. Probably need ballon tires or use on blacktop or concrete. Does someone have a web site for the motor/control parts?
Frank