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