Piping arrangement for a laser robot wrist

A piping arrangement for a laser robot wrist for supplying working media such as an assist gas and a liquid coolant through a plurality of supply pipe means to the robot wrist joined for rotation at least about one axis to an extremity of a robot forearm of the laser robot and holding a laser beam projecting device at a front end thereof;

• said piping arrangement comprising:
• a sheathing pipe means provided as an outer pipe of said robot wrist;
• a plurality of sealing means disposed on said sheathing pipe means of said robot wrist at appropriate spacings along a direction of an axis of rotary bearings supporting said robot wrist for rotation and provided in a joint joining said sheathing pipe means to said extremity of said robot forearm;
• a sealing means holding ring mounted on said plurality of sealing means for holding said sealing means in place;
• a plurality of annular chambers, each being formed between the two adjacent sealing means among said plurality of sealing means, and including at least one gas-carrying annular chamber and at least one liquid-carrying annular chamber;
• first working medium supply pipe means fluidly communicated with said gas-carrying annular chamber and said liquid-carrying annular chamber among said plurality of annular chambers and fixedly arranged close to and along an outer surface of said robot forearm to convey the assist gas and the liquid coolant;
• second working medium supply pipe means arranged close to and along an outer surface of said sheathing pipe means of said robot wrist to convey the assist gas and the liquid coolant through said gas-carrying annular chamber and said liquid-carrying annular chamber to a front portion of said robot wrist and to said laser beam projecting device, respectively;
• and
• compressed air passage means formed in an inner pipe extended within said sheathing pipe means of said robot wrist to apply pressure of compressed air through said inner pipe to predetermined annular chambers among said plurality of annular chambers formed on opposite sides of said gas-carrying annular chamber and on opposite sides of said liquid-carrying annular chamber to prevent leakage of the assist gas and the liquid coolant respectively from said gas-carrying annular chamber and said liquid-carrying annular chamber.