This document describes the parts and history of a pendulum clock. It was invented in 1656 by Christiaan Huygens, a Dutch inventor. The key parts are the escapement, gear train, pendulum, mainspring, and pointers. The pendulum regulates the time and its length and mass are important factors. The gear train uses different ratios to connect the mainspring to the hour and minute hands.

1. Pendulum clock
for dummies
Ivo Six
3IO
Constructieleer
Docent: Rino Versluys
400 days clock

2. History
Inventor: Christiaan Huygens
Year: 1656
Nationality: Dutch (Netherlands)
Error a day: 15 min ↔ 15 sec

3. Parts
Escapement
Mainspring
Gear train
Pointers
Pendulum

4. Pendulum
v
v
Fw
Fw
± point mass:
Spheres = Steel
Rest= Copper
Wire = Springsteel
 No deformation
 No loss of energy
Length = very important  time
Adaptable with bolt
Mass = not important
F1
F1
M1 M1

5. Escapement
F1F1
F2
F2 M2
Gear = Copper (big) & steel (small)
 Low corrosion & easy to produce (soft)
Axis = Steel
 Cheep

6. Gear train
Minute axis (3)
M3
Escapement axis 1 (2)
i(3-2) = z3a/z2b =
96/8 = 12
i(2-1) = z2b = 20
Escapement axis 1 (1)
2b
2a
3a
3b
60 min  1 tour 
number of returns =
1 x i(3-2) x i(2-1)
= 1 x 12 x 20 = 240

7. Mainspring
Springsteel
Wind up tool
Copper

8. 3b
Minute axis (3)
Mainspring axis 3 (4)
Mainspring axis 2 (5)
Mainspring axis 1 (6)
4a
4b
5a
5b
6a
6b
7
Mainspring(7)
i(3-4) = z3b/z4a =
8/60 = 2/15 = 0,133
i(4-5) = z4b/z5a =
10/60 = 1/6 = 0,167
i(5-6) = z5b/z6a =
12/60 = 0,2
i(6-7) = z6b/z7 =
12/90 = 2/15 = 0,133
400 days = 9600 hours =
9600 minute axis turns
Number of turns mainspring
= 9600 x i(3-4) x i(4-5)
x i(5-6) x i(6-7)
= 9600 x 2/15 x 1/6 x 0,2
x 2/15 = 5,7 turns

9. Pointers
3c (under)
Minute axis (3)
Hour axis 2 (9)
Hour axis 1 (8)
8a
8b 9
i(3-8) = z3c/z8a =
12/36 = 1/3 = 0,333
i(8-9) = z8b/z9 =
10/40 = 1/4 = 0,25
60 min  1 tour 
number of turns
hour axis =
1 x i(3-8) x i(8-9)
= 1 x 1/3 x 1/4 =
1/12 tour
Plastic axis (hour) &
metal axis (minute)
 Low friction
1 Hour