Circular saw having a saw arm angle adjusting device

A circular saw having a saw arm angle adjusting device, comprising a base, a saw arm, a rotation shaft mounted between the base and the saw arm, and an adjusting device mounted on the base for adjusting the angle of the saw arm, so that the saw arm may be pivoted through an angle, and may be positioned, wherein:

• the rotation shaft is provided with a gear portion, and a fixing bolt is extended through the rotation shaft, and has one end provided with a fixing nut for fixing the rotation shaft to prevent rotation of the rotation shaft;
• and
• the adjusting device includes:
• a drive shaft, movable axially;
• a drive unit, secured on one end of the drive shaft to move therewith, and having a first side formed with a first locking recess, and a second side formed with a second locking recess, for receiving and locking the fixing nut of the fixing bolt when the drive unit is moved to abut the fixing nut of the fixing bolt;
• a driven unit, rotatably mounted on the base, the driven unit having one end provided with a locking block that may be inserted into the first locking recess of the drive unit when the drive unit is moved to abut the locking block of the driven unit, the driven unit having an outer wall provided with a gear portion;
• and
• an adjusting unit, including a shaft rotatably mounted on the base, a first gear secured on a first end of the shaft and meshing with the gear portion of the driven unit, and a second gear secured on a second end of the shaft and meshing with the gear portion of the rotation shaft.