A toggle lever system with {HEAD ~ links} 13a, 13b engages each of {TAIL ~ the bearings} 11, 12 
A toggle lever system with { HEAD ~ links } 13a , 13b engages each of { TAIL ~ the bearings } 11 , 12
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH