Dimensioning head for plug gage

A plug gage of the type comprising a combination dimensioning head and detector,

• said dimensioning head comprising an elongated cylindrically shaped housing with a longitudinal axis and having an open end and a closed end,
• a gaging member mounted in said housing for movement along the longitudinal axis,
• said gaging member being normally biased toward the closed end and having a gage contacting portion projecting toward the open end,
• a pair of balls adapted to move and contact surfaces to be dimensioned exterior to said housing,
• said housing having a pair of stationary guide surfaces projecting in a direction transverse to the longitudinal axis, each guide surface forming a V-groove and being adapted to guide a respective ball,
• said gaging member being moveable in an axial direction and having outwardly facing non-rotatable arcuate surfaces,
• said pair of outwardly facing arcuate surfaces converging toward the closed end at a predetermined angle to the longitudinal axis, each of said respective balls being contacted by a respective guide surface and a respective arcuate surface,
• each V-groove presenting a pair of parallel lines of contact and each arcuate surface presenting a single line of contact with a respective ball,
• whereby said gaging member moves toward the open end as said balls are urged inwardly when contacting surfaces exterior to the housing during engaging.