Type "Püttmann 2"

Another première: Thomas Püttmann from Bochum (Germany) managed to implement the first chariot based on Planetary Gears.
It is roughly based on a sketch from my Taiwan Collection. He just saved the idler on the right by moving the right bevel gear set to the middle of the chassis.

A complete assembly instruction is available in the FischerTechnik Collection.

As usual, the dimensioning equations:

(a:) n₇ * rot₇ + n₈ * rot₈ = (n₇ + n₈) * rot₅

(b:) n₂ * rot₂ + n₃ * rot₃ = 0

(c:) n₄ * rot₄ + n₅ * rot₅ = 0

(d:) n₉ * rot₉ + n₁₀ * rot₁₀ = 0
The remaining constraints:

(e:) rot₁ = rot₂

(f:) rot₃ = rot₄

(g:) rot₈ = rot₉

(h:) rot₁₀ = rot₁₁

Composition

(e,b,f=>) rot₄ = - (n₂ / n₃) * rot₁

(c=>) rot₅ = (n₄ / n₅) * (n₂ / n₃) * rot₁

(h,d,g=>) rot₈ = (n₁₀ / n₉) * rot₁₁

(a=>) rot₇ = ((n₇ + n₈) / n₇) * rot₅ - (n₈ / n₇) * rot₈

(=>i:) rot₇ = ((n₇ + n₈) / n₇) * (n₄ / n₅) * (n₂ / n₃) * rot₁ - (n₈ / n₇) * (n₁₀ / n₉) * rot₁₁

To make it "south-pointing" requires, that if rot₁ is held 0, rot₇ has to be exactly one turn when wheel 11 of diameter d₁₁ covered one full circle (centre at wheel 1's contact to the ground, radius equal to track width t):

(j:) d₁₁ * rot₁₁ * PI = 2 * t * PI d₁ * rot₁ * PI = 2 * t * PI

(k:) rot₁ = 0 rot₁₁ = 0

(l:) rot₇ = -1 rot₇ = 1

(i=>) rot₁₁ = (n₇ / n₈) * (n₉ / n₁₀) rot₁ = (n₃ / n₂) * (n₅ / n₄) * (n₇ / (n₇ + n₈))

(j=>) d₁₁ = 2 * t / rot₁₁ d₁ = 2 * t / rot₁

The same method can be applied to calculate the required size for wheel 1, see rightmost column of table above.

Given Parameters (Your choice !)

Reference	Size	Description
2	n₂ = [teeth]	Bevel gear, fixed to left road wheel
3	n₃ = [teeth]	Bevel gear, fixed to left vertical shaft
4	n₄ = [teeth]	Spur gear, fixed to left vertical shaft
5	n₅ = [teeth]	Planet Carrier, free running on right vertical shaft
6	n₆ = [teeth]	Planetary gear
7	n₇ = [teeth]	Annulus of Planetary gear; carries the pointer
8	n₈ = [teeth]	Sun gear, fixed to right vertical shaft
9	n₉ = [teeth]	Bevel gear, fixed to right vertical shaft
10	n₁₀ = [teeth]	Bevel gear, driven by right road wheel
T	t = [length units]	Track width

Derived Parameters

Reference	Size	Description
1	d₁ = [units of t]	Road wheel, free running on axle
11	d₁₁ = [units of t]	Road wheel, free running on axle

(a:)	n₇ * rot₇ + n₈ * rot₈ = (n₇ + n₈) * rot₅
(b:)	n₂ * rot₂ + n₃ * rot₃ = 0
(c:)	n₄ * rot₄ + n₅ * rot₅ = 0
(d:)	n₉ * rot₉ + n₁₀ * rot₁₀ = 0

(e:)	rot₁ = rot₂
(f:)	rot₃ = rot₄
(g:)	rot₈ = rot₉
(h:)	rot₁₀ = rot₁₁

(e,b,f=>)	rot₄ = - (n₂ / n₃) * rot₁
(c=>)	rot₅ = (n₄ / n₅) * (n₂ / n₃) * rot₁
(h,d,g=>)	rot₈ = (n₁₀ / n₉) * rot₁₁
(a=>)	rot₇ = ((n₇ + n₈) / n₇) * rot₅ - (n₈ / n₇) * rot₈
(=>i:)	rot₇ = ((n₇ + n₈) / n₇) * (n₄ / n₅) * (n₂ / n₃) * rot₁ - (n₈ / n₇) * (n₁₀ / n₉) * rot₁₁

(j:)	d₁₁ * rot₁₁ * PI = 2 * t * PI	d₁ * rot₁ * PI = 2 * t * PI
(k:)	rot₁ = 0	rot₁₁ = 0
(l:)	rot₇ = -1	rot₇ = 1
(i=>)	rot₁₁ = (n₇ / n₈) * (n₉ / n₁₀)	rot₁ = (n₃ / n₂) * (n₅ / n₄) * (n₇ / (n₇ + n₈))
(j=>)	d₁₁ = 2 * t / rot₁₁	d₁ = 2 * t / rot₁