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BP-004 · Lever escapement
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1
1
2
2
3
3
4
4
5
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7
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8
A
A
B
B
C
C
D
D
E
E
F
F
R2.43
2.71
4.73
φ 0.0°
9
10
12
20
21
16
22
B
A
A
PLAN VIEW
FROM DIAL SIDE, MAINPLATE REMOVED · 20:1
17
18
DETAIL B
PALLETS · 50:1
7
6
3
4
5
DETAIL C
UPPER BEARING · 50:1
Ø9
2
11
8
13
15
14
19
1
C
SECTION A-A
BALANCE STAFF AND BEARINGS · 20:1
-300
-200
-100
0
100
200
300
12
24
36
48
0
125
250
375
500
TIME, ms (ONE BEAT = 125 ms)
BALANCE θ, °
WHEEL ψ, °
DIAGRAM 1
ACCENT: IMPULSE · DASHED: WHEEL ψ AND ±26° LIFT
NOTES
1. 28800 BEATS/h, f = 4 Hz. I = 10.9 mg·cm² (RIM + ARMS), k = I·ω² = 0.69 µN·m/rad.
2. HAIRSPRING 0.034×0.12, E 195 GPa: L = E·b·h³/12k = 111 mm, 9.4 TURNS.
3. LIFT 52°, LOCK 2°; WHEEL 10.3° IMPULSE + 1.8° DROP PER BEAT, 24° PER TWO.
4. T(WHEEL) 0.75 µN·m = 8.4 N·mm ÷ 8064 × η; Q 260 → AMPLITUDE 276°.
5. STAFF, ARBOR, PINS, JEWEL NOT CUT. TOUR SLOWS TIME AT EACH IMPULSE.
ITEM
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DESCRIPTION
MAINPLATE (PART)
BALANCE COCK
SHOCK BLOCK Ø1.9
CHATON Ø1.2
HOLE JEWEL Ø1.0×0.2, OLIVE
CAP JEWEL Ø1.0×0.12
LYRE SPRING Ø0.05 WIRE
BALANCE STAFF, PIVOTS Ø0.09
BALANCE Ø9.0, 3 ARMS
HAIRSPRING 0.034×0.12, L 111
HAIRSPRING COLLET Ø1.2
HAIRSPRING STUD
DOUBLE ROLLER Ø2.0/Ø0.9
IMPULSE JEWEL Ø0.28, D
PALLET FORK
PALLET ARBOR, PIVOTS Ø0.09
ENTRY PALLET STONE 0.245
EXIT PALLET STONE 0.245
GUARD PIN Ø0.10
ESCAPE WHEEL 15 CLUB TEETH
ESCAPE PINION z=7, m 0.065
BANKING PIN Ø0.30
MATERIAL
CuZn39Pb3, Ni PLATED
CuZn39Pb3, Ni PLATED
CuZn39Pb3
CuZn39Pb3
SYNTH. RUBY Al2O3
SYNTH. RUBY Al2O3
X10CrNi18-8
C100S, HARDENED
GLUCYDUR CuBe2
NIVAROX 1
CuZn39Pb3
X10CrNi18-8
C100S, HARDENED
SYNTH. RUBY Al2O3
C100S, HARDENED
C100S, HARDENED
SYNTH. RUBY Al2O3
SYNTH. RUBY Al2O3
CuBe2
C100S, HARDENED
20AP, HARDENED
C100S
QTY
1
1
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
TITLE
SWISS LEVER ESCAPEMENT
DWG NO
BP-004
SCALE
20:1
SIZE
A2
SHEET
1 / 1
DRAWN
CLAUDE
DATE
2026-10-15
MATERIAL
SEE PARTS LIST
GENERAL TOL.
ISO 2768-f
UNITS
mm · deg · ms
LIVE · DRAG THE BALANCE · ← → KICK · SPACE PAUSE · S SPEED · R RESTART
Drag the balance ·
←
→
kick ·
Space
pause ·
S
speed ·
R
restart
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