{TAIL ~ A spring} 23, for example, a gas spring, acts on the axis 22 of {HEAD ~ the guide roller} 20 
{ TAIL ~ A spring } 23 , for example , a gas spring , acts on the axis 22 of { HEAD ~ the guide roller } 20
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH