SAFETY DEVICE OF THREE-DIMENSIONAL MEASURING MACHINE

摘要

PURPOSE:To prevent a Z axis structure from falling securely in safety by uniting a Z-axis structure and the stationary body of the measuring machine body with each other mechanically by a locking means when the pressure in a cylinder drops by a specific value below the secondary air pressure of a pressure control valve which generate specific secondary air to be supplied to the cylinder for the air balance of the shaft structure. CONSTITUTION:The total weight of members which constitute the Z-axis structure 6 is balanced with the air pressure of a cylinder device 17. An abnormality detecting valve device 61 compares the pressure right after the secondary-side output of a flow rate control and pressure reduction valve 35 which sets the pressure in the cylinder 19 of the air balance device 17 to pressure matching with the weight of the Z-axis structure 6 with the pressure in the cylinder 19. When the pressure in the cylinder 19 drops by the specific value below the pressure right behind the secondary-side output, the cylinder device 53 is released and a lock pin 52 is inserted into either lock hole 42 of a lock member 41 through the operation of a spring 54. Consequently, the relatively simple constitution which uses only the air circuit prevents the Z-axis structure 6 from falling owing to the pressure drop in the cylinder 19.