Clock Design and �Design For Manufacturability (DFM)

Clock Project Overview

• Learn CAD and fabrication skills.
• Design For Manufacturability (DFM)
• Apply analysis to predict hardware performance.
• Report writing
• Today’s lecture: Clock Design
• Next lecture: Clock Timing

Mechanical Clock Technology

• The peak of engineering design at its time
• First “X-prize”
• Check out the EBU1-Clock
• Secret plaque on inside for finishers club
• Uses a flexure bearing like modern disk drives
• Millennium clock designed to tick 10,000 years

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In 1714 United Kingdom Offered a Reward of over $1 Million Dollars* that was Won with a Precision Clock

What was the purpose of the prize? (speculation)

1. Improve timekeeping for parliament meetings.
2. Improve marine navigation.
3. Improve United Kingdom's precision manufacturing capabilities.
4. Improve astronomy measurements.

Image from Wikipedia

* Equivalent to $1.3 Million US Dollars in 2015

United Kingdom’s Longitude Act of 1714

• To find a simple and practical method for the precise determination of a ship's longitude.
• Determining latitude was relatively easy �from altitude of the sun at noon.
• Knowing Greenwich mean time at noon on �the ship could determine longitude.
• Pendulum clocks in 1700’s accurate to 10 �minutes a day
• Needed accuracy of 5 seconds a day at sea.
• Story: https://en.wikipedia.org/wiki/Longitude_(book)

Longitude lines on

the globe

Wikipedia

Modern Day X-Prizes

• Founded in 1995
• Mission is to bring about “radical breakthroughs for the benefit of humanity”
• Reusable Suborbital Spaceflight
• Fly two times within two weeks
• Won in 2004 by SpaceShipOne designed �by Burt Rutan
• Automotive XPRIZE for 100 MPG Street Safe Car
• Won in 2010 by the” Very Light Car” with team lead by Oliver Kuttner
• Visited UCSD in 2013

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In 1581 Galileo Noticed How a Swinging Chandelier Could Be Used for Timing

What features of a pendulum did Galileo notice?

1. The period of an oscillation increases with amplitude.
2. The period of an oscillation decreases with amplitude.
3. The period of an oscillation was approximately the same at different amplitudes.

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Image from the Sail Power Steam Museum

For Small Angles of Oscillation the Period of a Pendulum is Constant Regardless of Amplitude

Small Angle Approximation

Wikipedia

https://en.wikipedia.org/wiki/Pendulum_(mathematics)

Independence from Amplitude:

https://www.youtube.com/watch?v=ItyPDM16QTM

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What is the purpose of the Hanging Nut? speculation

1. Increase speed of oscillation.
2. Balance weight of pendulum on front of clock.
3. Add fastener to clock.
4. Overcome friction in the mechanism.

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How Does the Escapement Wheel Work? Answer Individually

1. Teeth pushes right pallet horizontally to cause clockwise rotation of pendulum.
2. Teeth pushes right pallet horizontally to cause counterclockwise rotation of pendulum.
3. Teeth pushes left pallet vertically to cause counterclockwise rotation of pendulum.
4. Teeth pushes left pallet horizontally to cause clockwise rotation of pendulum.

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Weight rotates wheel, which in turn keeps pendulum oscillating.

Animation from Mark Headrick's Horology Page.

How Does the Escapement Wheel Work? Answer with Partner

1. Teeth pushes right pallet horizontally to cause clockwise rotation of pendulum.
2. Teeth pushes right pallet horizontally to cause counterclockwise rotation of pendulum.
3. Teeth pushes left pallet vertically to cause counterclockwise rotation of pendulum.
4. Teeth pushes left pallet horizontally to cause clockwise rotation of pendulum.

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Weight rotates wheel, which in turn keeps pendulum oscillating.

Animation from Mark Headrick's Horology Page.

Other Types of Escapement Mechanisms

Animations from Mark Headrick's Horology Page.

Drawing Your Pendulum

Holes are specified in Diameter (not radius)

Drawing Your Pendulum