An analysis of the spiral spring.

This thesis reports what is believed to be a new
approach to the analysis of the spiral (clock-type) spring
based on a re-thinking of the fundamental equations.
Detailed examination of this type of spring has
led to the discovery that the free spiral form approximates
to a logarithmic spiral. Methods of examining the free
spiral form are described and what are thought to be unique
methods ·of determining its equation are presented.
Knowledge of the spiral equation enables the
moment-rotation characteristic to be constructed which is
then compared with experimental results obtained on a
testing machine designed by the author. This machine
allows measurements of torque to be obtained without
introducing machine friction. It has been designed to
allovl autographiC recordings to be made of the spring
test.
Prediction of the spiral equation from
consideration of the elastic-plastic behaviour of an
idealised material has been achieved and charts have
been produced which will facilitate this prediction.
The relationship between the back-tension during winding
and the free spiral form has also been investigated.
A further research programme has been outlined
which, together with the present findings, should lead
to a complete understanding of the mechanics of the
spiral-spring forming process however performed.