Monday 17 September 2012

Early positive stop mechanisms

Sturmey Archer
Sturmey Archer
Sturmey Archer
Sturmey Archer
Sturmey Archer
Sturmey Archer

-SG- Andrew has kindly taken some photos of the original (1929) Sturmey Archer positive stop footchange (photo 1 to 6) as well as the copy he made of the later version (1931) for use on his Moore CS1 (photo 7 to 12).

Photos 1 to 6 show how the original system functioned. The assembly has incidentally, been attached to a down tube flat-tanker gear change mounting and shows sign of having been used with a CS gearbox as well as an LS, as an additional pair of neutral position grooves have been cut on the actual quadrant and an additional clevis pin hole is also present in the quadrant arm. The quadrant is a standard LS gear change component on which the pawl engagement  teeth have been cut and of which the centre has been machined out to fit over the boss of the actual pawl carrier. The gear selection grooves are still present in the quadrant at this stage in the design, and the corresponding back plate with two protruding detents (fairly well worn) is also a regular S-A gear change part, being used in both LS and 1929/30 CS gear changes.

Sturmey Archer copy
Sturmey Archer copy
Sturmey Archer copy
Sturmey Archer copy
Sturmey Archer copy
Sturmey Archer copy

In addition, the last series of photos below (photo 13 to 18) shows the 1930s NSU footchange which has a very distinct similarity to the Sturmey Archer type - hardly surprising in vew of Walter Moore working for NSU during the period 1929 to 1939.

1930s NSU
1930s NSU
1930s NSU
1930s NSU
1930s NSU
1930s NSU