Thus, the present invention can be implemented with {TAIL ~ either a compression spring} or {HEAD ~ a tension spring} 
Thus , the present invention can be implemented with { TAIL ~ either a compression spring } or { HEAD ~ a tension spring }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD