Portable hand-held length probe with tracing-unit-actuated length signal output control switch

A portable hand-held length probe, comprising

• a portable hand-held body with a nose wheel rotatably mounted thereon for length measuring movement over a surface,
• a movable tracing unit mounted in movable relationship on said body adjacent said nose wheel for movement relative to said body,
• spring means resiliently biasing said tracing unit to a first normal quiescent position, and said tracing unit being movable to a second position as a function of pressing said unit against a surface during tracing action therewith on a surface and in conjunction with rotational measuring movement of said wheel,
• signal means for effecting a length measurement indicative signal as a function of rotational movement of said wheel,
• and switch means carried by said body and responsive to movement of said tracing unit to said second position to enable passage of a said signal from said signal means, and said switch means being responsive to movement of said tracing unit to said first normal position to effect disablement of effective passage of said signal means signal.