Re: [CAD_CAM_EDM_DRO] Re: Rack and pinion

Dave Fisher wrote:

> All interesting stuff about the pros & cons of rack & pinion drive, I can indeed
> vouch for the accuracy and speed of the big Bystronic laser machines - and seeing them run
> is unreal !! However, could one of the many learned members of the group either
> point me to a site or in simple terms explain the concept of 'Preloaded' with respect to
> rack & pinions - I see this term in many posts and am not fully aware of what it means ?

One way to 'preload' a rack & pinion setup is to have a weight on a line
over a pulley to pull the axis back in one direction, so that the pinion
teeth are always bearing against one side of the rack teeth.

The other option I've seen, is a split pinion. It's made of two halves,
sandwiched like an oreo. One half is fixed to the shaft, and the other
can be rotated or spring-loaded to take up play between the pinion teeth
and the rack.