Abstract: A preform element comprises a substrate having an outer peripheral surface and at least one end surface. At least a portion of the peripheral surface of the substrate has bonded thereto an inner surface of a peripherally extending facing layer of superhard material, such as polycrystalline diamond. The portion of the peripheral surface of the substrate and the inner surface of the peripheral facing layer are provided with inter-engaging formations, such as ribs and grooves, whereby the peripheral facing layer is keyed to the substrate.

Abstract: A preform element includes a facing table of superhard material, such as polycrystalline diamond, having a front face, a peripheral surface, and a rear surface bonded to the front surface of a substrate which is less hard than the superhard material. The front surface of the substrate is formed around its periphery with an annular rebate having an inner edge, a number of spaced recesses adjacent the inner edge of the rebate, and projections of superhard material integrally formed on the rear surface of the facing table extend into the rebate and recesses.

Abstract: A preform cutting element for a rotary drag-type drill bit comprises a front facing table of superhard material having a front surface, a peripheral surface, a rear surface bonded to a substrate of less hard material, and a cutting edge formed by at least part of the junction between the front surface and the peripheral surface. The front surface of the facing table is formed with a chip-breaking formation which is located adjacent the cutting edge and is shaped to deflect transversely of the front surface of the facing table cuttings which, in use, are removed by the cutting edge from the formation being drilled. The chip-breaking formation may comprise a peripheral groove or rebate, or an upstanding ridge or insert.

Abstract: A method of thermally treating a preform element, of the kind having a facing table of polycrystalline diamond bonded to a substrate of cemented tungsten carbide, is disclosed. The steps of the method are: (a) heating the element to a soaking temperature of about 600.degree. C., (b) maintaining the temperature of the element at that temperature for two to three hours, and (c) cooling the element to ambient temperature. These steps are preferably then followed by a flash heating cycle. These steps are: (d) heating the element to a temperature in the range of 750-850.degree. C., (e) maintaining the temperature of the element at that temperature for about four seconds, and (f) cooling the element to ambient temperature. This thermal treatment relieves residual stresses in the element in order to reduce the risk of cracking or delamination of the element in use.

Abstract: A preform cutting element for a drag-type rotary drill bit includes a facing table of polycrystalline diamond bonded to a less hard substrate, such as cemented tungsten carbide. The element is formed by first forming a solid substrate, and then applying an electron beam, laser, or other intense heating source to adjacent areas of the front surface of the substrate to melt the surface and form an array of holes or holes therein. A layer of polycrystalline diamond particles is applied to the substrate so that such particles fill the holes or holes, and the diamond layer and substrate are then subjected to pressure and temperature in a high pressure, high temperature press to bond the superhard layer to the substrate. The engagement of parts of the diamond table in the holes or holes in the substrate provides a mechanical interlock to improve the strength of the bond between the table and substrate.

Abstract: A rail-type airborne missile launcher having a main launcher body for fixed attachment to an aircraft, and a sub-rail removably attachable to the underside of the launcher body to carry a missile, is further provided with individual hook modules that can be attached to the underside of the launcher body, when the sub-rail is removed, at selected locations along the launcher body to carry a variety of stores. Such hook modules can each carry a separate respective store or they can be employed as an oppositely-facing pair at a selected distance apart to both carry a single store. In the former case, the hooks will be operable separately, such as by electromagnetic means, for separate release of the stores; but in the latter case both hooks will be arranged to release simultaneously.

Abstract: A missile launcher is provided with pyrotechnically-operated means for jettisoning the missile. The missile is hung under a sub-rail latched to the underside of the main launcher body and upon operation of the jettisoning means the sub-rail/missile combination is slid rearwardly to disengage the latches after which the combination is given a downward thrust away from the launcher body, the thrust being imparted just forward of the collective center of gravity of the missile/launcher combination to cause its downward departure to be assisted by negative lift. The jettisoning means may consist of a lever and linkage actuated by a gas-operated piston-and-cylinder.

Abstract: A solenoid-operated device, and especially a weapon-arming device, subject to inertial forces is provided in which the solenoid armature is operatively coupled to a counterbalancing mass operatively constrained to move in synchronism with but oppositely to the armature, inertial forces on the armature acting equally and oppositely on the counterbalancing mass. The counterbalancing mass surrounds the solenoid coaxially and has an annular extension provided internally with rack teeth that mesh with sprockets free to rotate on fixed pins, these sprockets also being in mesh with rack teeth on an extension of the armature. An armature retraction spring bears on a shoulder on the counterbalancing mass.

Abstract: An airborne missile launcher is provided which is of modular construction to carry a variety of different missiles. A main body section has top attachment points, whereby it is carried by an aircraft, and a sub-rail hanger releasably attached at its underside which sub-rail preferably has a plurality of longitudinal tracks for carrying several different types of missile. To complete the launcher body, forward and aft body sections are attached to the main body section, each of which forward and aft body sections can be selected from a number of different such sections to suit different types of missile. The launcher also includes a nitrogen bottle carried right forward in a detachable fairing, a chaff dispenser carried aft, hold-back shoes to enable missile power up prior to translation relative to the sub-rail and convex bulged sides to reduce vertical stiffness and vibrations.

Abstract: A launcher is provided for a remotely piloted aircraft that has a launch ramp mounted on a transport vehicle and a carriage which is accelerated up the ramp carrying the aircraft to be launched. The carriage is hauled along the ramp by a cable leading to and wound around a winch drum which is driven by a flywheel through an electromagnetic slipping clutch, the flywheel being first run up to speed by an electric motor coupled to it by a torque limiting coupling. A hold-back device retains the carriage at the lower end of the ramp until the cable tension has built up to a predetermined value, and a brake system decelerates and arrests the carriage at the upper end as the aircraft leaves. On a short transport vehicle, the length of the ramp can be reduced for travel either by making it telescopic or by arranging it to fold about a hinge.

Abstract: An aircraft ejector release unit (E.R.U.) is provided in which ejection is accomplished by a pair of angularly moving ejection arms carrying pivotal thrust pads and both mechanically actuated by a common gas-operated piston-and-cylinder unit. The gas piston operates a crank that turns a central lever assembly coupled by actuating rods to rotate triangular cranks disposed near opposite ends of the E.R.U. Control links pivotally mounted at their upper ends on the E.R.U. body are pivotally connected at their lower ends to the ends of the ejection arms, and when the triangular cranks are rotated the ejection arms are extended by unfolding of the ejection arms and the control links, there being a pivotal connection between each crank and the respective ejection arm at a location intermediate the ends of the arm. Before the ejection arms extend, initial movement of the central lever assembly unlocks store suspension hooks of the self-releasing, sear type.

Abstract: An airborne missile launcher is provided which is of modular construction to carry a variety of different missiles. A main body section has top attachment points, whereby it is carried by an aircraft, and sub-rail hangers at its underside to receive alternative missile-carrying sub-rails each of which sub-rails has one or more longitudinal tracks for carrying one or more types of missile. The sub-rail may be mounted in telescopically sliding relationship with the main body section. To complete the launcher body, forward and aft body sections are attached to the main body section, each of the forward and aft body sections being selected from a number of different such sections to suit different types of missile. For certain missile types, the forward and aft sections may be simply a plastics fairing; for certain other missile types, the forward and aft section may house a missile umbilical retraction mechanism and other operative means.