Sunday, October 27, 2019

Variable speed drive demonstration model

Some relaxing tinkering with the vintage bits of Meccano. In addition to the instruction manuals and 'book of models', the Meccano Magazine is full of inspiration and little (and large) models to build.

In the December 1945 issue on page 422 is e.g. this very compact demonstration-model of a variable speed drive, sent in by a reader from Hull.

Built with Meccano parts from around 1930, a variable speed drive is built within the spirit of the illustration and text. As is very often the case, some deviations to make it possible with the fit and range of parts at hand.

And it does work, very well actually. The motor has a runtime of at least a full minute with 'power'. Using the handwheel then to change the pulley position as it is running causes the driven wheel to noticeably speed up or slow down, relative to the driving wheel.

The side view shows some of the changes and how the driven axle is supported. By adjusting the position of the driving faceplate/wheel (on the axle with the gear), the force of the rubber-tyred pulley on the driven plate can be adjusted. Adjusted so that it still drives without slippage and also does not press/jam everything solid.

A relaxing little puzzle to tinker  together - and a very neat, visible demonstration of variable speed drives. With thanks to A. Bedford of Hull.

1 comment:

  1. I enjoy all those old methods of making variable speed drives. Electronic drives take all the mechanical magic and creativity from variable sped. Much more cost effective though.