The bushing refers to a plain bearing. Most references to bushings will involve the roller shaft supports. Roller shaft bushings come in a variety of materials that have been matched with the application. If the bushing on your Shuttleworth system is worn at the bottom or broken, it is time to replace the bushing.
Make sure the equipment is locked out. Remove the bushing cover on the side of the conveyor. If the system is a belt driven conveyor, pull the cover out from the snaps. If the system is a chain driven conveyor, use a 17mm wrench to loosen the bolts. Then remove the cover. Pop out the roller shaft from the bushing holder. Remove the old bushing and replace with a new bushing. Push the roller shaft back into the bushing holder. Make sure the extruded part of the bushing faces the outside of the conveyor. Repeat steps 3-5 until all damaged bushings are replaced. If the cover is plastic it will snap back into place. If the cover is metal, place it over the bolts, then tighten with a 17mm wrench. Remove the lock out / tag out from the system and continue operation.
If the bushing on your Shuttleworth system is worn at the bottom or broken, it is time to replace the bushing.