| 摘要 |
PROBLEM TO BE SOLVED: To maintain a necessary track width even if two stop positions are secured with one brush by a method wherein respective patterns for respective brush pieces are so formed as to have the brush pieces transfer onto concentric circles having three different diameters step by step along with the turn in one direction. SOLUTION: A common pattern 40 connected to a motor M is formed to cross over the three circles R1 , R2 and R3 . The common pattern 40 can be brought into contact with at least one of brush pieces 45A, 45B and 45C over 360 deg., i.e., can transfer. Current-carrying patterns 41 and 42 are also formed to cross over the three circles R1 , R2 and R3 but they are not formed so as to be brought into contact with at least one of the brush pieces 45A, 45B and 45C over 360 deg.. The current-carrying patterns 41 and 42 can transfer onto one of the brush pieces 45A, 45B and 45C by the changeover between the contacts A and B of a switch 43. |
