My Senior design project - a "Swamp Thing" tracked vehicle clone

[texasranger556]

I would probably go with an electric clutch, brand new for $100 or less depending what brand/style you go with.

 

[K5lwq]

Not really Arly. I've been playing around a bit on the design of Snowzerblower which I may or may not build:

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Here's a design question for the group: when you look at the 5v belt being driven by the 20hp Onan engine, you'll see a belt tensioner device. This will act as a clutch to engage/disengage the blower by tightening/loosening the belt tension. I would plan to activate it with a small pneumatic cyclinder (under the housing) using a three-way solenoid valve inside the cab piped to an air supply. Do you think it work better as shown to push on the belt or should I move it to the inside of the belt to pull on it to tighten the belt? Stay well.

Just like you have it is best. Very effective. Looks like a nice design.

 

[Garauld]

I looked into electric clutches some time ago. I found that electric clutches with 1-7/16" IDs are uncommon and the pulleys tend to be too large for my needs. I have to slow the engine speed down a bit to run the impeller at a reasonable rpm (around 1000) so I mounted the smallest pulley I could fit on the engine shaft.

 

[ArlyA]

When I was putting together a snow tiller design powered via 35HP engine and needed to add a electric clutch to the setup, I looked and looked and gave up searching for a readily available one that could handle that much HP. I eventually found a company in the twin cities MN who built them.

 

[LittleBill21]

no i did not read this entire thing, i will throw this out about the master cylinder booster. my 2000 chevy 3500 express van. uses a master cylinder that is run off the PS pump for boost. it makes a huge difference, on a motorhome chassis,

also prolly dumb question, is all your cad stuff drawn literally from scratch?

 

[Garauld]

From the internet: "Heavy vehicles and cars with very quick-ratio steering boxes typically require higher pressures than lighter and lower-performing vehicles. At idle with the steering wheel static, a typical power steering pump holds about 80 to 125 psi in the output line. Yank the steering wheel a couple of times in rapid succession -- causing the pressure-release valve to flutter open and shut -- and a typical modern pump might momentarily put between 1,000 and 1,500 psi through the lines. Older and lower-performing pumps might run 850 psi of momentary pressure or less, while heavy-duty off-road pumps may sustain 1,600 or more. High-performance pumps can jump to 2,500 psi before the valve releases."

After I installed the vacuum boosters, I hooked up a 2300 psi pressure gauge to the output of my master cylinders and was able to peg it. I feel that should be enough pressure for the calipers to clamp the steering rotors. I do not plan to make any more changes until I play with it in the snow this winter.

is all your cad stuff drawn literally from scratch?

Pretty much everything except for nuts, bolts and other common items - I normally get those models from McMaster-Carr.

 

[KubotainNH]

Do you think it work better as shown to push on the belt or should I move it to the inside of the belt to pull on it to tighten the belt?

Pushing usually works better as the belt ends up with more surface area on the pulley. Looks like a cool setup.

 

[airbiscuit]

What is your air supply for the pneumatic cylinder to actuate the belt tightener?

 

[texasranger556]

I looked into electric clutches some time ago. I found that electric clutches with 1-7/16" IDs are uncommon and the pulleys tend to be too large for my needs. I have to slow the engine speed down a bit to run the impeller at a reasonable rpm (around 1000) so I mounted the smallest pulley I could fit on the engine shaft.

That is a strange size shaft. I've not seen it done before, but I'm wondering if there is any technical reason you couldn't mount an electric clutch on the jack shaft instead of the engine? That way you can size the jack shaft diameter to whatever clutch you come up with...in this case you'd want the biggest pulley available.

Drawback is the torque would be increased by the pulley ratio between the engine and clutch, so you'd have to take that into consideration selecting the clutch.

 

[Garauld]

What is your air supply for the pneumatic cylinder to actuate the belt tightener?

I would use a mini 12v air compressor that I would pipe up to a small tank and a pressure switch - the kind they sell for air horns.

 

[ArlyA]

I picked up a supply of 1/8 thick, black, UHMW which is about 4" wide. Do you need some?

 

[Garauld]

Hi Arly - I can't see a need for it at this time. Thanks for the offer.

 

[Garauld]

I got a new toy yesterday. I guess I should put it to work building Snowzerblower...

 

[ArlyA]

Can I borrow it?

 

[Garauld]

I have not been actively working on Snowzer or a Snowzerblower for it due to other projects (honey-do things). The new Eastwood welder seems to work nice for my needs. One of it's features is a tack weld option where, when selected, only powers the stinger for 1/2 second. This feature is good for those instances where thin sheet metal panels are to be welded. More expensive welders have this capability where the timer can be adjusted to suit the need, usually up to 10 seconds. This would be useful for making stitch welds.

 

[airbiscuit]

Any new videos?

 

[Garauld]

Hi - I've had it out about. The new vacuum boosters I added to the steering brake system work very well. I'll get the missus to take a new video in the near future. I've been tinkering again with my little motor-driven hydraulic system that could be potentially be used for pressurizing the steering brake calipers. I previously stopped working on it due to the supplied motor overheating too rapidly - see my writeup a few pages back. My new test setup uses a cheapo ($16) 12vDC drill from Harbor Freight to run the pump. I was able to generate 3000 psi with it with no sign of excessive motor heating since the drill is ventilated. It is also geared down for added torque unlike the previous motor. The plan might be to use a potentiometer attached to each steering brake arm to feed a signal to each 12vDC MOSFET motor driver unit (blue PCB) that would in turn, variably run each drill motor driving the appropriate pump. When the motor stops, the pressure bleeds off instantly thru the flow control valve. This is only something to play with and I don't have plans to implement it at this time. I attached an image of the HPU test setup. I plan to build Snowzerblower sometime over the summer. Stay tuned.

 

[Rockbadchild]

you still can get them stuck if the conditions are right

 

[Rockbadchild]

The first thing I see when I look at a machine like that is NEAT!!!

The second thing I think of is how many decades those tire ruts are gonna be there and the irreparable damage that thing will do to the environment in just one pass over an area.

it’s tracks not tires lol … tire ruts y’a can last a long time but we are the only one caring about them …

 

[Rockbadchild]

OK, I cleaned it up a bit...

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JK... :ashamed:

wow that’s a shop i could look at stuff around it for hours