{TAIL ~ The adjustment} may comprise {HEAD ~ a pair} of guide rods 48 on which a mount 48 for the lower roller 46 rides, with adjustable spring biasing means 49 
{ TAIL ~ The adjustment } may comprise { HEAD ~ a pair } of guide rods 48 on which a mount 48 for the lower roller 46 rides , with adjustable spring biasing means 49
TAIL TAIL TAIL TAIL TAIL TAIL 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