How Do People Design an Escapement for a Clock?
The escapement in a clock transfers the energy from the winding mechanism, suspended weight or coiled spring and helps control the oscillation speed within the timekeeping element. The movements of an escapement are what cause the ticking noise in analog watches and clocks. The locking action in an escapement allows a gear train within a clock to advance a hand on a clock’s face at a regular rate. The manner in which a person designs a clock escapement depends on the type of clock he wishes to make. You can learn to design and make clock escapements by taking horology classes.
Draw the escapement wheels on paper or a drawing program on a computer. A popular type of escapement that modern clockmakers use is the Graham, or deadbeat, escapement, according to horology expert Mark V. Headrick. To draw the Graham escapement, draw two concentric circles, which represent the escapement wheels. Draw a line through the middle of the center circle. Then draw additional lines through the middle of the circle that are 12 degrees apart on center. At the end of each line draw a line that extends 15 degrees toward the outer circle. Then draw another line back toward the middle circle that is at a 25-degree angle. When you finish, you will have a triangular shape at the end of each line. Repeat this process on the end of each line in the middle circle so you create 30 triangular shapes, or teeth.
Begin drawing the locking face of the escapement, which will go over the wheel. Draw a circle that matches the size of the largest circle you previously drew. Divide the circle into equal quarters by drawing two radius lines that have a 90-degree intersection. Then draw two more radius lines on either side of the original ones that are 3 degrees apart.
Draw the same radius lines over the drawing of the escapement wheels.
Finish drawing the locking face of the escapement. Line up the two lower radius lines of the locking face, or pallet, with the two upper radius lines of the escapement wheel so the middle lines intersect at a 90-degree angle. The intersecting radius lines will form four diamond shapes on either side of the escapement wheel drawing. Draw a vertical line between the two vertical diamond shapes on the right of the wheel and a horizontal line through the two horizontal diamond shapes on the left of the wheel. Erase the excess ends of the radius lines that surround the diamond shapes, as well as the radius lines within the escapement wheels.
Draw a horizontal line in the center of the circle you drew for the locking face of the escapement. Then draw two more radius lines that are 25-degrees apart. Connect the upper- and lowermost radius lines so you form a triangular shape in the lower part of the circle. Connect the outer edges of the triangle to the right and left curves formed by the circle, and follow the curves to the horizontal and vertical lines that you drew through the diamond shapes. Erase all the excess lines that you drew on the upper half of the circle. Then connect the inner edges of the triangular shape of the locking face to the inner ends of the horizontal and vertical lines that you drew through the diamond shapes, following the same curve as the line above it. After removing all the excess lines, you will have a drawing that resembles forceps above an escapement wheel.
Use the drawing to change the variables within the escapement according to the variables of the clock you are building or repairing. Bear in mind that the triangular shapes, or teeth, on the escapement wheel strikes the locking face so the wheel does not rotate too quickly.
- If you want more or less teeth, or triangular shapes, on your escapement wheel, divide 360 degrees by the number of teeth you want to learn how many degrees to separate each radius line on center. For example, if you want 36 teeth, you will separate each line by 10 degrees (360 degrees ÷ 36 teeth = 10 degrees).
- National Association of Watch & Clock Collectors, Inc.: Clocks and Watch Escapement Mechanics
- Princeton University: Who was George Graham?
- Watch and Clock Escapements: The Cylinder Escapement
- Abbey Clock: The Graham Explained
- Abbey Clock: Drawing an Escape Wheel
- Abbey Clock: Drawing the Graham Pallets