History Making robots
Grey Walter's Tortoises
||22 March 2015|
On the 22nd May 2009 Grey Walter's #6 was removed from its place of display in the Science Museum, London, to deep in the basement so Reuben Hogget and myself could examine it and take these photographs.
Photographs by David Buckley and Reuben Hoggett below
The long copper pipe. looking something like a tail. is an extension to the lever of the On/Off switch so it can be operated without removing the Shell.
Brunel University borrowed the Tortoise and decided to 'repair' it for an exhibition on Grey Walter in 1985.
The original lead acid battery and battery shelf were removed and replaced by the black plastic holder for four D-cells.
Also it looks like the original holder for the HT battery was removed and replaced by the aluminium shelf holding the five PP3 9v batteries.
The Terry-clips with the rubber band round them are to hold the photo-electric sensor when the tortoise is being transported.
In the third picture on the bulkhead behind the Terry-clips can be seen the identification number "6".
Here you can see the spanner, which only #6 carried, which presumably was used to adjust the contacts on the relays.
Apparently the operation, of #6 and the replicas, is very sensitive to the setting.
It was at this stage that I realised the front wheel and the 'eye' sensor were actually pointing backwards, the drive gearing should be on the right hand side.
To compensate, the shroud on the 'eye' sensor had been put on backwards - so as to face forwards!
By moving the steering motor by hand the front wheel was turned to face forwards.
Three of the photos (DSCF0175, DSCF0163, DSCF0164) in previous rows also show the corrected position.
Again, at the front, is stamped the identification number "6".
Underneath the red relay coil is one of the alternative 'eye' shrouds (see next row).
Here on each side you can see the silver shrouds covering the two 'brain' valves.
The shrouds really have nothing to do with the 'brain' valves but it was a convenient place to store them.
All three shrouds have different patterns for the light grill and are alternatives for the shroud covering the 'eye'.
One has vertical bars, one horizontal bars and the other diagonal bars.
Apparently in practice the different grills made little difference.
In the centre the brass plate held by the thumb-screw is the adjustment for the Shell contact which is the brass rod in the centre hole.
The other end of the rod is mounted in rubber and supports the "H" Shell bracket.
The turn-buckle is in the centre of the "H" Shell mounting and underneath is its rubber support (see previous row).
I needed a white backdrop so while the museum found one Reuben photographed #6.
The backdrop arrived so I could start.
In the first picture, if you look carefully at the ends of the cracks in the shell you can see tiny holes have been drilled to help prevent the cracks from spreading.
I think it is at this stage I realised that the front drive wheel was pointing backwards and the P.E.C. shroud has been put on back to front so effectively it pointed forwards.
You can see on the fork leg just above the axle an arrow which points backwards.
I think the curator is pondering our suggestion to turn the steering so it is pointing in the right direction.
The first picture shows the steering motor which was turned by hand, and in the bottom right on the front fork can be seen the arrow pointing forwards.
The sensitive area of the P.E.C. now points forward.
I always wanted to build a replica and here I am holding the original.
Reuben holding a dream.
The Tortoise has been reassembled and Reuben takes the final pictures before we say goodbye to #6.