Reference point return system

Abstract

A system is provided for carrying out a reference point return in a numerical control device. A deceleration dog (31) is arranged at a machine table (1) and includes a reference point (4). A deceleration limit switch (2) is operated when in contact with the deceleration dog (31), to generate a first deceleration signal (DEC1). A portion of the deceleration dog (31) from an end thereof with which the deceleration limit switch (2) first comes into contact to a predetermined distance therefrom is used as a hypothetical dog. A deceleration signal generating means generates a second deceleration signal (DEC1) when the deceleration limit switch (2) is in contact with the hypothetical dog. A reference point return processing means carries out a reference point return based on the first and second deceleration signals (DEC1, DEC2). Accordingly, an adjustment of the deceleration dog becomes unnecessary, and the assembling and maintenance are made easy.

Dependencies are inferred from the claim text.