Carriage positioning system

A carriage positioning system for positioning a first carriage movable along a first axis with respect to a frame, and a second carriage carried by and movable with respect to said first carriage along a second axis perpendicular to said first axis;

• characterized in that said positioning system includes two flexible coupling elements each for coupling one of the opposite ends of said first carriage for movement with respect to the frame;
• each of said two flexible coupling elements having its opposite ends fixed to the frame on the opposite sides of the respective end of said first carriage and being trained over a pulley carried by said first carriage on each of the two opposite sides of the carriage, and over a further pulley carried by the frame on each of the two opposite sides of said first carriage;
• each of said two flexible coupling elements being coupled to a first member for driving same or for being driven thereby;
• said second carriage including a single flexible coupling element fixed at its two ends to said frame at one side of said two carriages;
• said single flexible coupling element being trained over two pulleys carried by each of said first carriage, a further pulley carried by each end of said second carriage between the associated last mentioned two pulleys, and a still further pulley carried by said frame at the side thereof opposite to that to which the two ends of the single flexible coupling element are fixed;
• said single flexible coupling element being coupled to a second member for driving same or for being driven thereby.