Sunday, 3 October 2010

The Hand and the Turtle and a friends birthday present.

One of the benefits of having worked on automata for a couple of years before starting this blog is that I have quite a few photos and video's to upload of previous models I have worked on to put on here, whilst I struggle with the new ones.

The video above is a model I made for my friend who had recently become a father for the first time and it was also his birthday, so in honour of this I made a model of him. It is the first model I used incorporating a belt drive system and finding a suitable belt was quite a challenge. The only thing I could find at the time which was suitable was some rubber gloves with some cloth lining on the inside which cut into strips pretty well. The only problem was that it stretched over time, impairing the operation. I had to take it off and add some elastic bands on the pulleys in order to get the necessary grip.

Actually, there was another problem. I thought my friend was 30 this year but he was only 29, which is why I painted 30 on the football shirt. Oh well. 

The other model I am working on is something that has been on going for a while. It is a model of a hand with its finger tapping the shell of a turtle which causes it to snap back into the shell. 

This model has been causing me grief for a while. I thought I had gotten it susses (see video) but the operation was not smooth and a lot of effort had to be exerted in turning the handle, so I changed the mechanism to use a couple of pivoted levers. The mechanism is still causing a lot of trouble and this is probably due to the placement of the snail cam being too close to the spring meaning I am having to exert more effort (I think). I'll have to look at the diagram re levers and pivot placements but if this is the problem I'll have to re-think the design. Check out the video of the mechanism when it was nearly working. it is slightly out of time with the movement. 

I have since made a new case to house the mechanism and also allow me to modify it a little. This will involve more tinkering in the workshop but it's all good experience. I'll put some photo's up when I get a chance.

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