Ransomes made a collection of small crawler tractors. For more details, see Ransomes Motor Garden Cultivator Range
Well, I have a 2. The novelty of mine is I got it without the petrol engine with the intension of fitting a steam engine.
This is what it was like when I got it (sometime in May 1997). The front is the left hand side of the picture which is where the engine should be.
I intend to fit a Yorkshire type boiler to the front. Yorkshire (See picture below) boilers 'T' shaped flue or fire tube with the firebox in the middle of the barrel. The Barrel is placed transversly across with the tubes going out to the ends and then returning higher up to a central smokebox and then up a centrally mounted chimney.
The two sticks that you can see are brake band control for steering. They are mounted on top of a three compartment box, with a differential in the middle larger box and the brake bands in the two outer boxes.
Because I want to add a three point hitch (what you get on the back of a tractor for lifting and holding implements like ploughes, balers and harvesters) and power implements, I need hydraulics. If I were to use the main drive to power a pump, all my hydraulics would go when I stopped. So, to get over this, the steam engine will drive a hydraulic pump and two hydraulic motors will be fitted where the brakes were. These will drive via a gear reduction to the main drive sprokets. Steering will be done by putting bypass valves in parallel with the motors, both the motors being fed from a varaible flow valve for speed control and through 50/50 flow divider. This system will be fed from a 5 way valve to get forward and reverse.
The steam engine and pump will be placed horizontally in the bottom of the middle box. The current lift and hand gear, having been replaced, leaves room under the seat for a water tank and coal bunker. I will also add a tank each side over the tracks.
No new pictures just yet although I have some on film which is still in a camera somewhere. Instead of the bypass valves for steering I have thought about using a steerable flow divider. I found out about these from a patent search site. I managed to talk with the patent owner and found that the system was successful but he never found a market (he tried to sell the rights during the chat).
The other thing I have changed is the idea of putting the engine and pump in the middle box. (a) There won't be room for them and (b) the fire hole for the boiler is below the level of the top of the box - I will need to cut a section of the front plate away and change the top cover. I have already had to cut away a section of the two divider plates to accommodate the hydraulic motors.
The two hydraulic motors are now fitted. I hat to make mounting collars for them to place the pinions in the right place. I also had to get the motor shafts ground down and I ground out the pinions (pinion in the three jaw chuck and a carbide burr in the electric drill G clamped to the tool post - it worked but I failed to photograph it).
The back wheels and weight rollers are mounted. The tracks have been cleaned up - all 58 segments and 174 rubber sections and 116 clamp washers. All the 116 bolts had to be cut out. They have been replaced with stainless steel ones. The tracks still need to be tensioned but I will do this when the tracks are put on. The front wheel are the drive wheels and have 15 pins each with sleeves that can rortate on the pins. These engage with the track segments and rotate as they do so. These all need finishing to length and then need to be case hardend.
One other area that was holding me up was the issue of insurance. This has been resolved after talking to NTET The National Traction Engine Trust who have a suitable and well recognised insurance scheme although my boiler will fall just inside the size classed as a model. Given I'll be attending rallies and I'm not a member of any club currently, I thought this would give me good cover. Well if it's good enough for the traction engine boys then it should be okay for me.
Well, it's been some time. Due to changes in my personal life, not much has happened for a little while now. The little crawler has been striped, cleaned and painted. The tracks have new bolts. The motors have been fitted via mounting collars. The drive sprocket pins are part way through construction. Once these are completed and harden, the crawler should be rollable. Meanwhile, drawing work is being done for the boiler
After chatting my ideas through with various people I have come up with a hydraulic scheme which I am going to attempt to describe in words and pictures.
The pump feeds a set of cascaded priority flow dividers in series of priority. I want the lift to take priority over all so that the implement can be lifted out of harms way, the drive to take next priority and so to the controlled auxilary output, any remaining flow to be used by implements with their own controlls. The operator will be able to balance the needs of the drive and the implements.
Using the Ransomes plouging guide of one furrow at 2mph is 2hp approximately and designing higher to give me head room if required, I decided on a maximum no load speed of 6mph for which a flow of 90lpm is needed. Using an overall power of 5/6hp with the motors I have set the maximum pressure of the system to be 6hp at 2mph giving 80bar (if you see what I mean).
So now I need to get hold of the various hydraulic parts other than the drive motors. I can obviously design round what I can get hold of.
Yup - the scrounge section.
Any of the various hydraulic components
As yet I have not been able to come up with a good name for my steam crawler. Got any ideas? I'm sure I can find a prize for the one I use. Over to you.
As I make progress I will add some more pictures.