Wheel balancer parameter entry device

摘要

An improvement to a vehicle wheel balancer having a rotatable shaft upon which a wheel to be balanced is mountable and a digital signal processor, the improvement comprising a parameter entry device for determining the offset and diameter of the wheel which comprises an elongated rod slideably and rotatably mounted to the balancer in parallel with the rotatable shaft; a transverse arm connected to an end of the rod nearest the wheel, the arm comprising a wheel contacting tip; a first rotary encoder coupled to the distal end of the rod and having a shaft associated with the rod, wherein rotation of the rod rotates the shaft and thereby causes the first rotary encoder to generate a digital signal representative of the amount of rotation of the rod; a rack mounted to the balancer in alignment with the rod; and a second rotary encoder coupled to the rod and having a shaft associated with a rotatable gear which engages the rack, wherein extension of the rod rotates the shaft and thereby causes the second rotary encoder to generate a digital signal representative of the amount of extension of the rod; whereby movement of the wheel contacting tip into contact with the wheel causes the first and second rotary encoders to generate digital signals representative of the offset and diameter of the wheel.