They act as dampers and prevent damaging shock and rebound.
They absorb most of the accumulated kinetic energy on impact. GN 452 vibration / shock absorption mounts, also known as vibration isolation mounts, anti-vibration mounts, vibration bobbins or rubber bumpers, are used as end-stop bumpers, e.. GN452-25-15-M6-E-55 Rubber Bumper Stainless, Tapped These mounts are also used as leveling feet.