The actuator assembly 1 wherein one of said at least one knob is positioned on {TAIL ~ the distal end} of {HEAD ~ each guide rail} 
The actuator assembly 1 wherein one of said at least one knob is positioned on { TAIL ~ the distal end } of { HEAD ~ each guide rail }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD