Shock absorber for adjustable optical components

Claim 1

In an optical system including a lens support with a rail parallel to an optical axis and lens means having a part slidably guided by said rail for displacement between two limiting positions, the combination therewith of shock absorber means including a cylinder member with an open end and a piston member coaxial therewith confronting said open end, one of said members being mounted on said guided part with its axis parallel to the direction of displacement, the other of said members being mounted on a part of said support and being spaced from the other of said members during a major portion of a displacement stroke between said limiting positions, said piston member entering the open end of said cylinder member upon said lens approaching one of said limiting positions and being receivable in said open end with small clearance for cushioniNg the terminal movement of the lens by compressing the air trapped in said cylinder member, said piston member and said cylinder member being axially traversed by said rail, said cylinder member having a central boss hugging said rail and defining with the cylinder wall a ring channel, said piston member having an annular face spaced from said rail and receivable in said ring channel.