Medical apparatus and instruments castor accessories and selection methods commonly used medical truckle parts mainly include racks, sealing ring, the anti-wind cover, single wheel brake switch, all brake switch, steering lock, etc. Respectively as follows: the effect of a brace: mainly is the device below the transport, can make its fixed at a particular location on the device. Others include steering arm, leverage, rubber fenders, locking pad and other spare parts with a specific purpose. Second, sealing ring, prevent to bearing or bearing of single wheel into dust, maintain its lubricity, easy to turn. Three, the anti-wind cover: to prevent and other sundry wrapped around the gap of shaft and support with wheels. To rotate the wheels can be free. Four, single wheel brake switch: on the wheel axle sleeve or tire surface, with the hand or foot operated brake switch device. Five, the brake switch: can lock steering device can be fixed wheel brake button again. Six, steering lock: through the spring bolt locking to bearing ( Four or two locking) The event medical casters, locking for fixed medical casters. To choose appropriate materials of castor wheels, the wheels usually made of nylon, rubber, polyurethane, elastic rubber, cast iron, plastic, etc. Polyurethane wheel without wheels are driven in the ground of indoor and outdoor, can meet the requirements of handling; Then select the diameter of the caster wheel size: usually the wheel diameter is larger, the easier it is to promote the greater carrying capacity is also can protect the surface from being damaged, wheel diameter size first consideration should be given the choice of load and load carrying the weight of the object of starting thrust to decide; To calculate again good caster wheel bearing weight: according to the weight of equipment, the maximum load and the number of single wheel and castor used, a single round or castor to calculate the required load ability; Can finally choose flexible turning wheels: single wheel rotation, the more the greater the effort, needle roller bearings can carry heavier load, turn the light is more flexible.