Coupling mechanism 10 includes a driving arm 11 directly coupled to output shaft 5, {HEAD ~ a driven arm} 12 directly coupled to shaft 3, and an elastic coupling member 13 for elastically coupling driving arm 11 to {TAIL ~ driven arm} 12 
Coupling mechanism 10 includes a driving arm 11 directly coupled to output shaft 5 , { HEAD ~ a driven arm } 12 directly coupled to shaft 3 , and an elastic coupling member 13 for elastically coupling driving arm 11 to { TAIL ~ driven arm } 12
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH