Needle Bar Rocking Mechanism - Brother RH-981A Service Manual

3. ASSEMBLY

3-10-2. Needle bar rocking mechanism

3750Q
3751Q
Adjusting the positional relationship between the needle rotation pulley assembly M and the
looper base
1. Align the match mark in the looper base (1) with that in the bed, as shown in the figure.
2. Turn the needle rotation pulley assembly M (2) until the pin (3) makes contact with the motor base.
3. Attach the timing belt.
4. Make sure that the looper base (1) can rotate through 360° easily.
* Tighten the screw of the looper pulley at the front.
Adjusting the timing belt tension
Attach the timing belt D while the tension pulley arm D assembly is being pulled by a force of 68.6 N.
* Deflection in the center of span: 6 ± 0.5 mm when 4.9 N is applied.
RH-981A
35