60
28. Changing the flat-toothed belt
Removal:
• Remove the housing in accordance with the adjustment and repair instructions.
• Turn the handwheel until the lobe of feed eccentric 5 is positioned at the rear (fig. 66).
• Loosen fastening screw of tensioning roller.
• Tilt the machine to the rear.
• Unscrew and remove fastening screw 98 of clamping plate 99 on the lower right calotte bearing.
• Remove the clamping plate.
• Slip off flat-toothed belt 100 from the upper and lower belt wheels 101 and 102.
• Lift complete hook driving shaft 28 out of the lower right calotte bearing 103 as far as it will go.
• Pull the flat toothed belt between calotte 104 and calotte bearing 103.
• Disconnect tension spring 105 on needle bar frame 106 (fig. 67).
• Remove lockwasher 54 on the needle bar frame.
• Remove circlip 107 on zigzag stepping motor 51.
• Dismantle the complete connecting rod 108.
• Loosen screw 109 on needle bar crank 110.
• Unscrew and remove both clamping plate screws 111.
• Dismantle both clamping plates 112.
• Lift the arm shaft with the crank as far out as possible from calotte bearings 113 and 114.
• Hold the needle bar crank firmly.
• At the same time move arm shaft 115 to the right until both parts are disengaged.
• Dismantle the complete arm shaft.
• Remove the flat-toothed belt from the housing to the top.