Abstract: An abrasivejet drilling system is disclosed for drilling small diameter holes in fragile materials of the type which tend to crack when impacted by such jets. The system employs a drilling jet formed from a high pressure liquid whose pressurization varies with time during the drilling process. To avoid damage to fragile materials, angular holes are drilled by initially penetrating the surface of the fragile workpiece perpendicular to the workpiece's surface and thereafter pivoting the jet to the correct angle. The jet dwell in the drilled hole for a predetermined time to modify the hole geometry is monitored by detecting the change in sound level when the jet drills completely through the workpiece.

Abstract: An abrasivejet nozzle assembly is disclosed which is particularly suitable for drilling small diameter holes in a workpiece. Such assemblies include a mixing region wherein abrasive particles are entrained into a high velocity waterjet formed as high pressure water is forced through a jet-forming orifice. Among the unique features of the nozzle assembly are an inwardly tapered abrasive path just upstream of the mixing region, flushing conduits immediately upstream and downstream of the mixing region, and a venting passageway upstream of the mixing region which prevents the backflow of abrasive dust towards the jet-forming orifice.

Abstract: An abrasivejet system for cutting brittle materials is disclosed. One feature of the disclosed system is a jet-producing nozzle assembly which includes means for inducing turbulence in the jet-forming liquid during the period in which the jet initially impacts on the brittle material so that impact stress on the material is reduced. A second disclosed feature is a supplementary suction device, preferable in the form of a second nozzle dimensioned for maximum suction, which maintains a generally constant feed rate of abrasive into the cutting nozzle assembly during the turbulence-inducing phase of operation.

Abstract: Water at a very high pressure (e.g. fifty thousand psi) is directed through a nozzle orifice to produce a coherent high velocity water jet particularly adapted for cutting. Prior to pressurizing the water and directing it through the nozzle, the water is treated to remove dissolved solids, desirably to an extremely low level to provide very pure water (e.g. where the total dissolved solids are as little as ten parts per million or lower). This is done by directing the water through several ion exchange reactions to precipitate the solids which are then removed by filtering. The operating life of the nozzle is greatly extended by this process.

Abstract: An expansible drive shaft tool mechanism is disclosed in which mutually cooperating parallel drive shafts carry tool elements that can be shifted into and locked by shaft expansion in any of selected positions along such drive shafts. Applied hydraulic pressure in a sealed chamber causes outward expansion of a flexible outer sleeve member on each such shaft to grip the tool elements. An inner sleeve member closely encircled by the outer sleeve member and joined in sealed relationship therewith at opposite end portions forms the radially thin elongated annular sealed chamber into which the pressurized hydraulic fluid is forced by the action of a plunger type hydraulic pressure source housed inside the inner sleeve member cavity. Actuation of the hydraulic pressure source plunger passing through a cylindrical fluid take-up chamber by longitudinal displacement is effected by means of a pneumatic piston energizable through a connecting line including a low pressure rotary seal or union.

Abstract: A high velocity, constant flow, liquid jet cutting apparatus comprising a source of high pressure fluid, a jet nozzle, and a high pressure conduit to carry the fluid from the source to the jet nozzle. Immediately upstream of the jet nozzle is a liquid collimating device comprising a housing interconnected between the conduit and the nozzle and defining a flow collimating chamber directly upstream of the nozzle, through which the high pressure liquid is delivered to the nozzle. The cross sectional area of the flow collimating chamber is at least greater than 100 times the cross sectional area of the nozzle opening, and desirably in the order of four hundred times as great or more. The resulting liquid jet has relatively little dispersion of the liquid and is capable of effectively cutting a relatively narrow kerf with a high quality finish and little, if any, wetting.