Diameter gauge for machine tools

Claim 2

A diameter measuring gauge for a machine tool comprising a pair of opposed feelers for contacting opposed points of a workpiece each said feeler being mounted respectively on an arm, a pair of sleeves slidable relative to one other, each of said sleeves supporting one of said arms, a shaft, substantially parallel to the plane of movement of said feelers, said sleeves being slidably and coaxially mounted on said shaft, one of said sleeves including an annular portion spaced from said shaft and having an inner surface overlying the outer surface of said other sleeve in telescopic relationship thereto, the other of said sleeves overlying the surface of said shaft, fluodynamic means connected to each of said sleeves to move said sleeves relative to one other, and electrical means connected to said sleeves for sensing the position of one of said feelers with respect to the other of said feelers and generating an electrical signal indicative thereof.

Claim 3

A gauge according to claim 1 further comprising first rolling bearing means disposed the leNgth of said other sleeve for movably supporting said other sleeve on said shaft and second rolling bearing means interposed between said inner surface of said annular portion of said one sleeve and said outer surface of said other sleeve.

Claim 4

A gauge according to claim 1 wherein said fluodynamic means comprises a pair of hydraulic motors arranged in parallel to one another, said hydraulic motors each being operatively counterconnected with said pair of sleeves for moving said sleeves in opposite directions, thereby moving said feelers relative to said workpiece.

Claim 5

A gauge according to claim 3 wherein said feelers, said arms and said sleeves are in vertical alignment with one another, the upper one of said sleeves being connected to its respective said hydraulic motor by means of a one-way coupling allowing only upward motion to be imparted by said hydraulic motor and having a first tension spring connected between the frame of the machine tool and said upper sleeve to bias said upper sleeve upwardly with a predetermined force, the lower one of said sleeves being connected to its respective hydraulic motor by means of a one-way coupling allowing only downward motion to be imparted by said hydraulic motor and having a second tension spring connected between the frame of said machine tool and said lower sleeve to bias said lower sleeve upwardly with a predetermined force, said upper feeler contacting the workpiece under the action of gravity partially counterbalanced by said first tension spring and said lower feeler contacting the workpiece under the action of said second tension spring, whereby said hydraulic motors drive said sleeves apart to allow the workpiece to be interposed between said feelers.

Claim 6

A gauge according to claim 3 wherein said arms are parallel to one another.

Claim 7

A gauge as claimed in claim 1, wherein said electrical means comprises a first electrical winding mounted on a first board fixed to one of said sleeves and a second electrical winding mounted on a second board fixed to the other of said sleeves and spaced from said first board by an air gap and electrically coupled across said air gap to said first winding, said boards being movable with said sleeves to alter the electrical coupling across said gap thereby indicating the relative displacement of said sleeves.