carriage odometer replica

Discussion in 'Clock Construction' started by Charles Morrill, Jul 20, 2016.

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  1. Charles Morrill

    Charles Morrill Registered User

    Apr 11, 2014
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    Hello, I'm trying to create a schematic replica of an antique horse drawn carriage odometer bolted to an axle cross tie and actuated by an exterior arm, ratchet, and pawl arrangement actuated almost like an old revolution counter on a marine reciprocating steam engine. In the case of this odometer, a cam on the wheel hub caused the arm to rise and fall.

    Unlike a revolution counter, however, the odometer had a clock face to count miles and tenths of miles.

    My question has to do with the motion work for the hands.

    It would be nice to use some beefy stock gears if possible as this is for a museum and will get the living daylights used out of it. The device has a clock face with a dial from one to ten. The "hour" hand will read miles and the "minute" hand will read tenths of miles, so the reduction for the motion work is from 1 to 10 instead of from 1 to 12 as in a clock face.

    My thought is that I'd use the following gears for the motion work: a 12 tooth, 24 pitch, .5 inch pitch diameter meshing with a 120 tooth, 24 pitch, 5 inch pitch diameter for the 1/10 reduction all in one go. If I'm correctly understanding things, this would mean the gears are 2.75 apart on center.

    The 12 tooth is driven by two gears of an equal number of teeth (English pattern of doing things?) I'm thinking I'd use two 24 pitch gears of 66 teeth, pitch diameter of 2.75 inches each, which if I'm understanding things correctly would mean the gears are once again 2.75 inches apart on center. Thus the 12 tooth and one of the 66 tooth gears would be attached together on a single shaft.

    Does this make sense or am I missing something? I'm somewhat surprised I can use gears of the same pitch all around as I've sometimes read that motion work requires gears of different pitches to make this all happen.

    Many thanks for your time and understanding.

    Charles Morrill
     
  2. novicetimekeeper

    novicetimekeeper Registered User

    Jul 26, 2015
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    I have something a bit similar, a waywiser from the early 18th century. I only have the movement but it is driven by a wheel of known circumference and has a dial like a small longcase clock. Measures in miles, furlongs, poles and chains.


    attachment.jpg


    This is how it looked when I bought it.


    attachment.jpg attachment.jpg
     
  3. Charles Morrill

    Charles Morrill Registered User

    Apr 11, 2014
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    I do like waywisers! Though most seem to have been driven with a single wheel attached to a handle and dial, there were some that looked for all the world like carriage clocks and sat on a wheelbarrow arrangement. The worm and square drive shaft that plugs into a longer shaft going down to the wheel seems pretty typical but no doubt someone on the board will know much more than I....
     

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