a conveyor system comprises pairs of vertically spaced and horizontally oriented pulleys and belts that are positioned on opposite sides of a conveyor path . the belts wrap around the pulleys and engage with opposite sides of an object being conveyed by the conveyor , for example an empty plastic blow molded bottle , and convey the object along the conveyor path between the belts . a vertical adjustment mechanism quickly adjusts the vertical positioning of the pairs of pulleys and belts on each side of the conveyor path to quickly adapt the conveyor for conveying different sized objects .