Laser beam working head with automatic adjustment of focussing optical lens - in which lenses holder which supports focussing optic lens can be moved vertically by automatic adjustment means

摘要

Laser beam working tool in which the lens holder (3) which supports the focusing optic lens (2) can be moved vertically by automatic adjustment means which may be pneumatic, hydraulic or electric. Pref. an area inside the tool housing (1) is divided into two pressure chambers (8, 9) by the holder (3). Each chamber can be filled with a fluid of either a gas or liquid. The chamber (9) may be fed with a process gas used to work the workpiece. Possibly both chambers can be fed with process gas. The top chamber (8) is fitted with a valve regulated (16) feed conduit. The pressurised surfaces of the lens holder (3) in both chambers are large and different. The holder is movable against a spring located at the bottom of the housing. The lens holder may alternatively be moved by an electromotor (23) or piezoelectric drive in which case a protective gas cover (24) is provided to separate the holder (3) from the process gas entering the bottom chamber. The lens holder can move vertically between upper and lower optimal positions. The actual position is achieved by a unit (21) which moves the holder in response to a measurement of distance between workpiece and housing. ADVANTAGE - The focal point of the optic lens can be automatically adjusted by moving the lens holder even during a working operation.