GB1450251A - Creating holes in members - Google Patents

Abstract

1450251 Perforating by laser beam REED IRRIGATION SYSTEMS 8 Jan 1974 00883/74 Heading B4B Apparatus for making a hole in a member, e.g. a plastics tube for use in irrigation, comprises means 22, 52 for moving the tube through a hole making station, and directing means 36, 40, 42 for moving a laser beam 18 against a region of the tube as that region passes through the hole-making station, the directing means being synchronised with the moving means such that no relative movement takes place between the tube and the point of contact of the laser beam as the tube passes through the hole-making station. The tube to be perforated is urged by a pair of spring-loaded rollers 52 into a groove 48 formed in the periphery of a wheel 22, which is rotated by a variable-speed motor 32. A laser-beam generation device 16 directs the beam via mirrors 20 on to a mirror 36 mounted on a plate 38 secured to the wheel 22. The beam is directed via a condenser lens 40 on to a further mirror 42 which directs the beam through an aperture 44 in the periphery of the wheel and on to the surface of the tube. The beam is energised each time an abutment 64 on the wheel operates a switch 66, thereby determining the spacing between the holes in the tube. A control device 68 is provided for controlling the length of time the beam is energised and its intensity such that a hole is formed in the wall of the tube on one side only; the control device can be used to vary the size of the holes along the tube. The tube can be formed with an interior partition 74 through which a further hole may be formed, the holes being formed at an angle so that they are longitudinally offset with respect to each. In a modification, Fig. 7 (not shown), three sets of mirrors and condensers lenses are mounted on the wheel for cooperation with their respective peripheral holes so that the numbers of holes produced in the tube per revolution of the wheel can be increased.