In {TAIL ~ the embodiment} shown, elastic coupling member 13 is formed as {HEAD ~ a spring member} 
In { TAIL ~ the embodiment } shown , elastic coupling member 13 is formed as { HEAD ~ a spring member }
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD