On 29/11/2020 14:41:30, Chris Green wrote:
Chris Green wrote:
"Dave Plowman (News)" wrote:
How does the spindle lock work on a drill? The type that lets you use a
keyless chuck one handed? More specifically, how does it disengage when
you switch on?

On drills with a keyless chuck it's a type of gear[ing] that only
works when transmitting power in one direction. I guess it's a bit
like a ratchet except that it works on both directions. There's a
specific name for it which I'm afraid I can't remember. :-)

Not a very good explanation, using 'direction' with two different
meanings!

It's a type of gear train that will transmit power from A to B but
locks when transmitting power from B to A.

At the very simplest level (but it isn't this) think of a worm gear
which will transmit power from the rotating worm gear to the pinion
but won't allow the pinion to be rotated.

I presume like a Quaife differential? The only spindle locks I've seen
are manual, where a peg stops rotation of a shaft.