X-Y Plotter for producing diagrams from computer information

Claim 1

An X-Y plotter comprising: (a) a frame (b) a pen carriage equipped with recording pen means to make marks on a recording surface; (c) a slider upon which said pen carriage is movably mounted for sliding motion in a first direction thereon, said slider means being movably mounted on said frame for sliding motion in a second direction orthogonal to the direction of pen carriage movement; (d) a first driving means for moving said pen carriage along said slider, which comprises a first driving motor and a first wire mounted in a closed loop not fixed to said frame, said loop including said motor and said pen carriage; (e) a second driving means for moving said slider in said second direction, which comprises a second driving motor and a second wire mounted in a closed loop not fixed to said frame including said second motor and said slider; and (f) tension means engaging said first wire for keeping said first wire free from slack; wherein said tension means comprises slide means which is equipped with a pair of pulleys, one of which engages said first wire and is movable along guide means in the second direction; and a slack-preventing wire having one end fixed to said slider and the other end fixed to said frame and engaging another pulley of said slide means so that said slack-preventing wire keeps said first wire free from slack through said slide means.