Custom UTV

[aczlan]

Not sure what to think about that suspension. Very unusual. Can you please explain it's purpose? I'm assuming you are using it to adjust ride height?

The object (per earlier parts of the thread) is to make a "box" on the front where he can drive a wheelchair into and run the machine from there so as to access areas where a powered wheelchair cannot go.

The suspension will allow the front to "kneel" and make a gently sloping ramp to drive the wheelchair into.

Aaron Z

 

[aczlan]

I've come up with an idea for a suspension system, for my machine's front-end. It's a little crude yet, but I'm looking for little bit of feedback before I refine it more. I've attached a few photos, and also did a video animation of how it works. Let me know what you think.

I see 4 possible issues:
1. When you hit a bump, will the arm drop enough to bottom out? How about when you have it "kneeling" will it hit the ground?
2. Will the shock/lift assembly bend when you hit rough terrain?
3. How big are the rods on your lift cylinders? Will they bend at full extension?
4. Could you run the hydraulic lines in a different fashion? If you snag the lower line for the lift cylinder on a branch and break it off, you will be stuck.

IMO, you would have a simpler design with the ram and the shock(s) on the same side of the pivot as the tire.
Perhaps something like this:


If you are going to be very far off of the pavement by yourself, I might also add a backup electric actuator on each side to lift the front up in case you blow a line somewhere. Below is one way that it could be done. No suspension, but it would get you back without needing to wait for help:


Aaron Z

 

[whodat90]

How about instead of trying to get the suspension to do all the work, use a center section similar to a drop-bed trailer?
http://www.practicalmachinist.com/v...er-rental-san-fernando-valley-ca-img_9883.jpg

 

[kdlklm]

How about instead of trying to get the suspension to do all the work, use a center section similar to a drop-bed trailer?
http://www.practicalmachinist.com/v...er-rental-san-fernando-valley-ca-img_9883.jpg

that was one of my original designs, to use the lowering floor instead of a kneeling system. The more I think about it, the more I am inclined to go back to that design. the only problem I have with that is the shaft that supports the motor mount.

 

[PapaPerk]

The object (per earlier parts of the thread) is to make a "box" on the front where he can drive a wheelchair into and run the machine from there so as to access areas where a powered wheelchair cannot go.

The suspension will allow the front to "kneel" and make a gently sloping ramp to drive the wheelchair into.

Aaron Z

Ahhh I see. :thumbsup:

Here's my thoughts.... I would use a Firestone airbag and small shock absorber. That would be simpler and more durable.

If I was designing such a rig, I would make the front of the unit a fold down ramp that the operator could simply drive or push the wheel chair up. Then the ramp would flip back up. Similar to a WWII infantry landing craft.

Of course these are just my opinions! :thumbsup:

 

[PapaPerk]

Another option is to use the ramp idea coupled with tilting the bed (where wheel chair sits). This will provide a smooth transition and would be easy to implement with one hydro cylinder. :thumbsup:

 

[whodat90]

Since you're using hydro motors, you can just put them wherever it's convenient and chain drive down to the drive wheels. Imagine the trailer I posted, but it's back is your front. Motors go on it's front, chain drive down to the wheels. Alternately, since they're hydro, there's no particular reason you couldn't hang them above the wheels facing out, and chain drive down, unless they're way too long.

Another option is to simply go with the ramp idea, but have a grabber in the UTV that reaches out and pulls the chair inside. Then, so long as you don't fall out the angle is somewhat irrelevant. Think of a flatbed tow truck and it's winch.

 

[kdlklm]

here are a few updated photos of where things are at now. I'm looking at going with an air ride suspension that also will work as a kneeling system. I spoke with Ride Tech and they told me that their system would work perfectly for this. So we are looking at using 7000 series shock absorber with a 6.9 inch stroke. Air ride is a little pricey, but it will kill two birds with one stone. And from everything I've researched it's very reliable and should last me a long time. Let me know what you think of this.

 

[PapaPerk]

here are a few updated photos of where things are at now. I'm looking at going with an air ride suspension that also will work as a kneeling system. I spoke with Ride Tech and they told me that their system would work perfectly for this. So we are looking at using 7000 series shock absorber with a 6.9 inch stroke. Air ride is a little pricey, but it will kill two birds with one stone. And from everything I've researched it's very reliable and should last me a long time. Let me know what you think of this.

Can you post a bottom view? Curious how the swing arms are attached to chassis.

 

[kdlklm]

right now, I just have them attached to the back. I'm not sure that's going to be my final design yet.