The threshold force is adjustable by changing {HEAD ~ the axial position} of {TAIL ~ the compression spring seat} 
of
The threshold force is adjustable by changing { HEAD ~ the axial position } of { TAIL ~ the compression spring seat }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL