Steve, where I work there are lots of electric 'plinths' (treatment
couches) that have an electric ram to adjust its height. These can cope
with the weight of two people sitting on it and the lever arm is quite
short.
the ram extends only about 8" though and the motor inside was 24V DC on
the units we have. When I played with it it ran quite happily on 12V.
Its not a pivot pin and snap on mounting, it has forks on each end.
Maybe you could source a used one and see if it does the job, just
remove the transformer and control board in the housing.

Klaus

Steve wrote:

Cause I'm looking for a 12 volt electric linear drive.

I guess I should have avoided the use of the term "ram".

Sorry.

Steve
s/v Good Intentions