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