Apparatus 17 wherein the included angle of the tapering section is at least twice the angle whose tangent equals {HEAD ~ the static coefficient} of friction between the test contact member and {TAIL ~ the test probe} 
Apparatus 17 wherein the included angle of the tapering section is at least twice the angle whose tangent equals { HEAD ~ the static coefficient } of friction between the test contact member and { TAIL ~ the test probe }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL