Method and relevant apparatus for the indirect measurement of the longitudinal development of curved seats or grooves in mechanical workpieces

An apparatus for the measurement of the longitudinal development between the ends of a groove defined in a workpiece by two side surfaces having a part-circular profile of unknown bending radius, comprising:

• a frame;
• a support, carried by the frame, for supporting the workpiece;
• a first measuring device arranged at a side of the workpiece, said measuring device including:
• a first measuring element for contacting the workpiece at one end of the groove;
• a second measuring element for contacting the workpiece at the other end of the groove;
• and first position transducer means coupled to said elements for providing a signal responsive to the distance between the ends of the groove along the straight line passing through said ends;
• a slide carried by the frame;
• a second measuring device carried by said slide at a side of the workpiece, the second measuring device including:
• a first member comprised of two feelers stationary with respect to each other;
• a second member comprised of a third feeler movable in a transversal direction with respect to the line passing through said stationary feelers;
• an oscillating support, carried by said slide, for supporting said first member and second member and permitting said stationary and movable feelers to contact three relevant points on a side of said groove;
• and second position transducer means coupled to said movable and stationary feeelers to provide a signal responsive to the distance between the movable feeler and said line passing through the stationary feelers;
• thrusting means coupled between said frame and the slide for displacing the slide to bring the stationary and movable feelers towards said side of the groove;
• a retracting device coupled to said slide for displacing it to a rest position adapted for inserting the stationary and movable feelers into said groove;
• and
• processing means for processing the signals provided by the first and second transducer means to obtain the longitudinal development of the groove.

An apparatus for measuring the longitudinal development of seats for side seals of a Wankel rotor, comprising:

• a frame;
• a first support, carried by the frame, for positioning and supporting said rotor;
• a first measuring head arranged at a side of the rotor, said measuring head including two measuring elements for contacting the rotor at the ends of a seat for a side seal and a position transducer coupled to said elements for providing a signal responsive to the distance of said ends along a straight line;
• a slide mounted on the frame;
• a second support pivotally mounted on said slide;
• a second measuring head carried by said second support, said second measuring head including:
• two adjacent contact members fixed to said second support, for contacting two points on a side wall of said seat;
• a third contact member movably mounted on the second support for contacting a third point on said side wall;
• and a position transducer coupled to said fixed and movable contact members for providing a signal responsive to the distance of said third point from the straight line passing through said two points;
• means acting on said slide for displacing it in a determined direction to bring said fixed and movable contact members towards said side wall of the seat;
• control means coupled to said slide for displacing it from a measuring position where said fixed and movable contact members contact said points to a rest position for making easier the introduction of the fixed and movable contact members into said seat;
• and processing means for processing said signals provided by said measuring heads to obtain the longitudinal development of the seat.