{HEAD ~ A central portion} between the housing portions 40a has a communication hole 12a for vertically movably containing {TAIL ~ a cam} 12 and a stopper groove 40b 
{ HEAD ~ A central portion } between the housing portions 40a has a communication hole 12a for vertically movably containing { TAIL ~ a cam } 12 and a stopper groove 40b
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH