Six Speed binary ratios sequential gearbox

[Ian PParticipant @ianp]

Just putting this here for general interest.

It is part of a Shackman oscilloscope camera probably manufactured in the 1960’s. It has a small induction motor driving the 35mm film at speeds (according to the dial markings) from 1″ to 32″ per second!

Ratios are 1:1, 2:1, 4:1,… 16:1

The black item on the right is a six position detented knob that drives a pinion engaged with a rack carrying the sliding output gear.

For scale, the shafts are 1/4″ and 3/16″ diameter, on ballraces and pinions are bronzed bushed ‘they certainly dont make them like that anymore’

Ian P

 

 

[Michael GilliganParticipant @michaelgilligan61133]

Lovely !

MichaelG.

[duncan webster 1Participant @duncanwebster1]

It took me a while to work out how it operates. Variable speed motors have made things a lot easier

[noel shelleyParticipant @noelshelley55608]

VERY NEAT. Noel.

[Ian PParticipant @ianp]

This is what the complete unit looks like.

The rectangular flange on the horizontal conical tube fastens to the front of an oscilloscope and the angled cone allows the scope trace to be viewed, it has a hinged flap to shut off external light. Camera has a 36mm Wray lens with a Prontar shutter. The lower enclosure contains the motor drive to the camera which is in diecast body, the rest of the painted metalwork is brass sheet all beautifully formed and soldered, some of the other parts and constructional details are just exquisite.

In the gearbox picture, the input is the large drilled wheel one nearest the camera and the output is the bevel gear is at the top. The large gear is driven by the motor and only the two pinions (smaller one is hidden) nearest the input end are fixed to the shaft, all the other pinion pairs on both shafts are free to rotate. Sliding gear that picks off the chosen ratio runs on a keyed shaft.

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