When actuators travel a full stroke, the internal piston contacts the cylinder’s end-cap. For high speed or high load applications that can mean a loud and sudden impact and lead to premature wear.
Cylinders with bumpers have thin elastomer pads that reduce metallic noise at the end of the stroke. This means quieter operation, a big benefit for employees who work near the equipment.
Because they are so thin though, bumpers aren’t designed to dissipate kinetic energy that can cause damage. Adjustable air cushions decelerate loads at the end of the stroke to reduce noise and impact. The rod slows down just before the end of stroke. When a piston nears the end cap a sleeve engages with a special seal to produce a cushion of air that slows down the piston. Turning the adjustment screw on the cylinder head increases or decreases the cushioning effect.
Engineers generally specify cushions on the rod end, the cap end or both ends of the cylinder depending on their application need.
There are also models available in multiple lengths – longer cushions for heavier loads, shorter cushions for lighter loads.