I found a septuagenarian comedian who was capable of taking a fall. This is a scene from Rock-a-bye Baby (1958) showing 71-year-old Hank Mann being knocked down repeatedly by Jerry Lewis. Mann is first knocked down when Lewis, in his clumsy effort to fix an aerial, smashes up a chimney and sends bricks raining down on Mann's head. One brick strikes Mann squarely in the head and knocks him unconscious.
Lewis is trying to revive Mann when he trips over a high-pressure hose and yanks the hose loose from a fire hydrant. Mann no sooner regains consciousness and gets to sit up then Lewis, unable to gain control of the hose, blasts Mann in the face with a stream of water and knocks him flat again.
I have been doing research on Mann for my upcoming book. I also found this cameo that Mann performed with Snub Pollard in The Man of a Thousand Faces (1957).
Lewis had Mann in a number of other films, although the parts were not always prominent. Mann was cast as a fight manager in Lewis' Don't Give Up the Ship (1959), but viewers never saw more than the back of the actor's head.
I should add that, in The Man of a Thousand Faces, Pollard also took a pie in the face.