Hydrostatic ATV

[mjncad]

The frame looks better with the extra cross-members. This is a better design whether you use hydraulics, pneumatics, or linear actuators.

What about linear actuators used for wheelchair lifts on vans that don't have air brakes? I suspect those things see quite a bit of muck.

 

[kdlklm]

the latest photos, I'm feeling really good about this design now. Does anybody see anything that you don't like about it. The feedback is been invaluable. It's very much appreciated. Especially the ones that took all the time to do the sketches. Let me know what you think.

 

[mjncad]

Thinking about this more I'm wondering if you're going to put some sort of counterweight on the engine side of the vehicle. Since the wheelchair compartment side will weigh in around 600-pounds as I recall, and that Subaru or similar engine isn't going to weigh nearly that much. Even if you had a hydraulic reservoir as large as 20-gallons, you're still only looking at about 120 - 130 pounds in hydraulic fluid weight.

Also since this is an ATV, I'm wondering about suspension for the wheels, or are you relying on low pressure in the tires for soaking up the bumps? I'm thinking you could be in for a bone rattling ride even at low speeds.

I'm also starting to wonder if an articulated vehicle is the best choice. Obviously you can't straddle an engine being in a wheelchair; but I'm wondering if some sort of arrangement could be designed where you're sitting more or less between the axles instead of over one of them would make for a better ride and stability, and the maybe less complexity.

In any case, this is a fun thread due to the design challenges.

 

[kdlklm]

Thinking about this more I'm wondering if you're going to put some sort of counterweight on the engine side of the vehicle. Since the wheelchair compartment side will weigh in around 600-pounds as I recall, and that Subaru or similar engine isn't going to weigh nearly that much. Even if you had a hydraulic reservoir as large as 20-gallons, you're still only looking at about 120 - 130 pounds in hydraulic fluid weight.

Also since this is an ATV, I'm wondering about suspension for the wheels, or are you relying on low pressure in the tires for soaking up the bumps? I'm thinking you could be in for a bone rattling ride even at low speeds.

I'm also starting to wonder if an articulated vehicle is the best choice. Obviously you can't straddle an engine being in a wheelchair; but I'm wondering if some sort of arrangement could be designed where you're sitting more or less between the axles instead of over one of them would make for a better ride and stability, and the maybe less complexity.

In any case, this is a fun thread due to the design challenges.

I did strategically place the front wheels for the weight transfer balance. The weight on the front wheels should be almost exactly the same as the weight on the back wheels. And when I drive off the rear weight should be adequate.

A suspension system has been tossed around for a little while, and I think it's something I really want to do. Air ride was one of the suggestions, but I'm open to anything at this point. I'm hoping to start building in a couple weeks so I really need to come up with something quick.

The articulating design, is probably one the simplest designs, especially when it comes to steering. The hydraulics and electronics are very simple to.

Thanks for your input, I highly encourage any opinions or suggestions.

 

[aczlan]

A suspension system has been tossed around for a little while, and I think it's something I really want to do. Air ride was one of the suggestions, but I'm open to anything at this point. I'm hoping to start building in a couple weeks so I really need to come up with something quick.

How about something like this:

With a motorcycle spring/shock on the load side and a actuator/ram on the other?

Aaron Z
(This post contains attachment # 210,000...)

 

[kdlklm]

How about something like this:
View attachment 210000
With a motorcycle spring/shock on the load side and a actuator/ram on the other?

Aaron Z
(This post contains attachment # 210,000...)

I got thinking about how the suspension will react when I'm driving my chair off the ramp. When I drive my front wheels off, half the weight of my chair is off the machine which will make the suspension spring up and make my chair wanna flip forward. The same thing happens with my wheelchair lift on my van, if it's not flat on the ground. I will have to come up with a workaround for that.

 

[aczlan]

I got thinking about how the suspension will react when I'm driving my chair off the ramp. When I drive my front wheels off, half the weight of my chair is off the machine which will make the suspension spring up and make my chair wanna flip forward. The same thing happens with my wheelchair lift on my van, if it's not flat on the ground. I will have to come up with a workaround for that.

I would have a stop where you lower it, then when you drop it all of the way down, it is resting on the stop instead of the shock/spring.

Aaron Z

 

[kdlklm]

I would have a stop where you lower it, then when you drop it all of the way down, it is resting on the stop instead of the shock/spring.

Aaron Z

I would have to come up with a way to put it into the lowering system. Because if I put it underneath it will reduce my ground clearance. And I don't want do that. Do you have any suggestions.

 

[aczlan]

I would have to come up with a way to put it into the lowering system. Because if I put it underneath it will reduce my ground clearance. And I don't want do that. Do you have any suggestions.

Make the actuator/ram longer than the shock and put in a stop with a rubber "bumper" (shown in red below) to end travel for the swing arm

Then to put it into "kneeling" position you retract the actuator/ram until the spring is unloaded and the arm is resting on the bump stop (perhaps even put in a sensor to turn on a light when that happens)

Aaron Z

 

[kdlklm]

Make the actuator/ram longer than the shock and put in a stop with a rubber "bumper" (shown in red below) to end travel for the swing arm
View attachment 210331
Then to put it into "kneeling" position you retract the actuator/ram until the spring is unloaded and the arm is resting on the bump stop (perhaps even put in a sensor to turn on a light when that happens)

Aaron Z

that's a good idea, I wonder if there is a shock absorber that would attach directly to the end of the actuator. Have one that screws on to the end. Because if I had just a few inches of travel, that would probably be more than adequate. I have seen shock absorbers that are that small.

But that would probably bring me back to my original problem of having the front-end spring up, when driving off the machine.