A guide roller is a roller that is used to point or guide an object in a particular direction. On a boat trailer, the guide roller is the first roller in which the boat makes contact with when loading. The keel of the boat rides in the saddle of the guide roller and assists the boat in loading straight up a series of rollers onto the trailer. When used in a household door application, the guide roller maintains the door in a track, ensuring that the door closes and opens properly and straight, and is typical in closet door applications.
The purpose of the guide roller is to maintain the integrity and alignment of a particular object while it is in motion. This can be a drawer, door, fence or even a tank track. By placing a guide roller into position on any moving object, it will follow the path of the roller and track in a straight and orderly manner. The ability to roll allows for an easy movement with the least possible resistance. This also prevents unnecessary damage to the object being guided into position.
In the use of a cable-operated object such as a crane cable, the guide roller is located on the end of the boom. The cable runs through the roller and is able to move with no resistance. This not only allows for easy lifting, it prevents fraying of the cable that would surely happen if the cable was pulled over a piece of flat steel many times. The rolling action of the guide also prevents cutting through the material by the cable.
In a portable winching situation, the roller allows the winch to pull much easier by providing a rolling surface for the cable to operate on. This uses less power to pull the cable in and provides more winching time on the battery before it is drained. The roller also provides for a much smoother pull on the cable, resulting in less stops and jerks while in operation.
The guide roller also aids in the smooth spooling of a cable. In applications such as an elevator, the cable is wound onto a spool as the elevator travels along its path. The guide ensures that the cable will wind onto the spool in an even manner instead of simply winding in one area and piling up on the spool. This would create a cable that is pinched and could easily become stuck or frayed. The guide roller helps the cable to last much longer than it otherwise would.