| 摘要 |
PURPOSE:To enable easy fixing of two sprocket wheels at a specified position according to the paper width by change the outer diameter of an angular shaft of a paper feed tractor. CONSTITUTION:A dovetail-shaped thread 21 and a dovetail groove-shaped recessed groove 22 are provided respectiviely on the contact surfaces between fixed wedge-shaped sections 19a and 19b and mobile wedge-shaped sections 20a and 20b of an angular shaft 11 of a paper feed tractor. The mobile wedge- shaped sections 20a and 20b is slidable along the length of the angular shaft 11 by fitting them together. When operation knobs 24 and 24 in operation mechanisms 14 and 14 are loosed to slide the mobile wedge-shaped sections separately in the directions B and D, the outer diameter (d) of the angular shaft 11 reduces. Under such a condition, sprocket wheels 12 and 12 are slid over the circumferential surface of the angular shaft and stopped at the position according to the width of a paper. Then, the operation knob is reversed to increase the outer diameter (d) of the angular shaft 11 and the position of the sprocket wheels are fixed. |
