a spring provided on {HEAD ~ the base} means in an upright position for pushing the rotatable frame upward at a point near one of the pair of the bearings which support {TAIL ~ the follower roller} 
a spring provided on { HEAD ~ the base } means in an upright position for pushing the rotatable frame upward at a point near one of the pair of the bearings which support { TAIL ~ the follower roller }
OTH OTH OTH OTH 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 OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL