A delayed blog post this week, as I was preoccupied for a while with MRI scans and the buying of a car, but here we go, better late than never!
Sunday was a day of progress, and we got a few things done.
Sometime since the last post, Colin had acquired a winch, a video of its pulling power below,, which will later become the mechanism for closing the jaws. Using a chain going to each jaw, being tied into one, and when the motors engages, the force pulls both jaws shut simultaneously.
Our main task for the day was fitting this into the machine, which was surprisingly simple, it just took a single piece of metal being fabricated, drilled into it, and a nut welding to one side of it for easy tightening and later removal, then the metal being welded inside and winch pulley being mounted to it. The winch uses its own motor, which needs to still be positioned. The motor uses the same voltage as the main motors, so a seperate power source or system isn't required, but only optional depending on some factors later down the line.
We also worked out a return system, using some springs so, when the motor has disengaged, the jaws return to their open position near immediately. This system currently needs a little more refining, but the proof of concept was certainly there.
Part of the jaw opening requires a double sprocket, so the motor can turn it with a little chain, and in turn, turn the other chain leading to the jaws. This is to stop us needed an exceptionally long chain that might be prone to being knocked out of place or off the sprocket, two smaller chains may be more reliable than an exceptionally long one. I'll be going to a local store in Wakefield that sells bearings during the week to acquire this.


Sundays images,
1 An image of the actual winch Colin acquired, it was taken off the plank of wood prior to installing into the bot.
2 A close up of the jaw mechanism, showing the springs used to return the jaws to position when the pulling motor disengages.
3 The current state of the internals, after the winch system was installed, still to do is fitting the controlling motor, this will be done next week most likely.
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There's also two videos;
Demonstrating the action of the jaws, demonstrated by Colin pulling on the control chains here, they were hard work to pull, so never quite made it to full closure, but it certainly gives you an idea:
The strength of the motor in the winch, we're intending on using this motor, but we're aware we might need something a little more powerful to not only pull the jaws together, but also maintain a good grip on anything caught in the jaws. So the end force may be stronger than this:


Some machines have a death hum, but if those jaws are anything to go by, we have a death rattle!