a retainer curved surface for engaging the actuator lever, rolling contact between the retainer curved surface and an actuator lever surface being caused by {HEAD ~ depression} of {TAIL ~ the pushbutton} 
of
a retainer curved surface for engaging the actuator lever , rolling contact between the retainer curved surface and an actuator lever surface being caused by { HEAD ~ depression } of { TAIL ~ the pushbutton }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL