|Pete White||11/02/2019 20:19:09|
|41 forum posts|
Engineering porn, great photos, keep up the good work and posts, much appreciated.
2225 forum posts
Howard; a couple of pics of the cobbler automaton would be nice.
|Howard Lewis||14/02/2019 01:45:53|
|1694 forum posts|
Sadly, was so obsessed with sorting it out that took no pictures. Should have, if only to show the damage and bodges, (likely to make matters worse ), previously present.
Would guess, from the telephone number on the baseboard, that it was pretty old (020 code)
Basically, a geared shaded pole motor drove a multilobe cam. The follower is on a lever which pivots on the left frame. The lever carries three screwed rods, with ball joint ends, which run vertically upwards. The undamaged one nods the head, the two that needed straightening and adjusting operate the right arm, wielding the hammer, and the outer one, a bell crank which drives a horizontal rod at shoulder level, which causes the left hand to sweep to and fro across the shoe on the "anvil".
The fact that the two rods had been bent in compression implied some fairly large forces, (hence the original motor ran, but did not drive the output shaft ).
The cam had been fitted inside out, making the grubscrews inaccessible, which explained why it was loose on the shaft! When fitted with the hub outwards, the cam was running out. It was secured to an arbor, in the lathe and checked with a DTI. The DTi was moved away to allow gentle persuasion, or levering, at appropriate points, until it ran reasonably true again, (1mm+ reduced to less than 0.2mm ) At least the cam now stayed in the groove in the ball bearing follower. Having dispensed with the pack of washers, a solid spacer was turned up to align the follower with the cam.
Adjusting the rods took time, because to make any adjustment meant removing a ball joint, giving it one turn and refitting, before checking the effect of the adjustment.
Once operating satisfactorily, the back was fitted; which promptly stalled the motor! The ball joint on the outer rod fouled. The rod was refitted with the ball joints inboard, but a foul still remained. This was cleared by drilliing a hole in the plastic back, and steadily carving bits away, to extend it, until the foul cleared.
From its state, the shirt was even older than the ones that i wear in the workshop; and that's saying something!
The new owners seemed impressed with my description of the "as received" condition, the repairs,and the "after" operation, that they gave a bigger donation to Club funds than I had expected.
So everyone was happy!
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