DualVee - Bishop-Wisecarver - #29

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3 Wheel Carriage 4 Wheel Carriage 6 Wheel Carriage It is important to note the location of the eccentric wheel is dependent on whether the track guide way is on the outside or inside of the wheel carriage. Below are several wheel carriage configurations (examples given for bottom image, opposite page). Diagram Symbols: = Concentric guide wheel = Eccentric guide wheel = Radial loading direction Wheel Preload Generally wheel preload is used to eliminate play between the wheel and track. Preload equals the radial load when the system is not loaded by another outside force. Preload can be determined by: Preload = Breakaway Force/Coefficient of Friction – Applied Load Caution must be used when applying preload because too much preload on the wheels can cause premature failure. The rated radial value should never be exceeded by the preload and subsequent radial loads applied to the wheel when in service. Note that in a four guide wheel assembly sustaining a load that runs along a long beam, preload on the wheels cannot compensate for deflection of the beam. Normal adjustment is obtained by rotating the eccentric bushing until all free play is removed from the carriage assembly. When the eccentrics are adjusted and the carriage plate is held firmly in place, one should be able to rotate by hand any one of the four guide wheels against the mating track. If rotation is not possible the preload should be reduced accordingly. Typically in a guide wheel and carriage application, there should be two concentric mounted wheels and the rest of the wheels should be on eccentric mounts. The eccentric type guide wheels are used to create a camming action to preload the guide wheels against one side of the guide track. Concentric Eccentric Side View © Bishop-Wisecarver Corporation 2010. All rights reserved. www.bwc.com 888.580.8272 27 Motion Without Limits ®