{HEAD ~ The other end} of the oscillating arm 24 is formed with a plurality of {TAIL ~ internal threads} 241 adapted to engage with a gear 25 fixedly mounted on an output shaft of a motor 20 
{ HEAD ~ The other end } of the oscillating arm 24 is formed with a plurality of { TAIL ~ internal threads } 241 adapted to engage with a gear 25 fixedly mounted on an output shaft of a motor 20
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH