| 摘要 |
PROBLEM TO BE SOLVED: To ensure safety while satisfying the swing motion by driving a movable blade further upward or downward when an uppermost or lowermost oscillation angle is reached and stopping a heat generating means when an upward or downward motion' can not be confirmed. SOLUTION: An oscillation designation signal S25a from an oscillation designating means 25 comprising a switch, or the like, at an operating section designates to start operation at an oscillation control section 26. An operation angle designating signal S26a for swinging a variable blade is delivered to a variable blade drive section 24 and the oscillation angle is set at an uppermost or lowermost oscillation angle. A signal S26b is delivered from an oscillation control section to an abnormality confirming timer 27 at that moment to start measurement of time. When upward or downward motion of the variable blade is not recognized within a specified time being set by the abnormality confirming timer 27, a heat generating means, i.e., a burner 3, is stopped. |
