Abstract: The invention provides a finger follower body defining a downwardly opening dome at one end, the dome having a seat which is a spherical band having a center and being concentric about a center line. A downwardly facing and downwardly convex valve contact surface is provided at the other end of the follower, and a pair of side walls define openings aligned about an axis. The openings are positioned in the side walls so that a bearing mounted in the openings will be essentially above a first imaginary line drawn between the center of the spherical band and the valve contact surface. The center line converges with another imaginary line drawn through the axis and at right angles to the first imaginary line. A finger follower incorporating the body is also provided.

Abstract: The invention provides a rocker arm and a method of making it having a cold formed steel body including parallel side walls and a bearing housing in the form of a sleeve attached to the side walls and defining a through opening to receive needle bearings. The sleeve has surfaces resistant to gas hardening so that after the arm has been subject to gas hardening only the main body is hardened leaving the sleeve unaffected. A method of making the rocker arm according to the invention includes preparing a sleeve having a surface which is resistant to gas hardening and which is unaffected by brazing temperatures; attaching the sleeve to the arm by brazing; and gas hardening the completed arm at a temperature less than the brazing temperature.

Abstract: A finger follower arm is provided for mounting on a support post to transmit oscillatory motion from a cam to a poppet valve to cause the valve to move linearly between open and closed positions. The arm has a support post end including a downwardly open domed socket for engagement on the support post and an upstanding peripheral wall. A tappet valve end defines a downwardly open channel having parallel side surfaces and a downwardly facing bearing surface between the side surfaces for engagement with said poppet valve. A pair of upstanding spaced-apart side walls extend between the support post end and the tappet valve end and blend into the peripheral wall which extends continuously between the side walls to rigidify the support post end. A method of manufacture is also described.

Abstract: A nitride of a metal or solid metalloid is produced by ball milling a powder of a metal or metalloid in a nitrogen, or nitrogen-containing atmosphere (such as ammonia). The pressure in the ball mill is normally from 100 to 5,000 kPa, typically about 300 kPa. The ball mill temperature may be from room temperature to 500.degree. C., preferably from 200.degree. C. to 400.degree. C. The product powder is normally pressure moulded and annealed at 800.degree. C. for about 1 hour to produce a strong, hard body. Controlling the degree of nitration, or mixing the product nitride powder with a metal powder before pressure moulding, enables a composite comprising a metal matrix with a dispersed nitride phase to be produced. An alternative technique, involves ball milling the metal or metalloid powder with an organic nitrogen-containing chemical which dissociates in the ball mill. This yields a mixture of the nitride and carbide of a metal or solid metalloid.

Abstract: A ball mill for use in mechanical alloying and grinding comprising a plurality of ferromagnetic balls within a spherical or cylindrical chamber or cell of a paramagnetic material. The chamber has a substantially horizontal axis of rotation. At least one magnet is mounted outside the chamber to produce a magnetic field within the chamber. The magnet is physically moveable, relative to the chamber, between a plurality of locations on an arc centered on the axis of rotation of the chamber.

Abstract: Metal carbides may be formed by mixing metal powder with a stoichiometric amount of graphite, compressing the same in a mould/die and then sintering. High temperatures (and maybe a bonding agent) are required to effect the final step and finished product. These disadvantages are overcome by exploiting dry high energy milling to bring the starting materials into a very finely divided and reactive state, with regions of metal, carbon and metal based solid solution ranging from 3 to 100 nanometers in diameter. As an alternative source of carbon, cationic organic surfactants may be used instead of graphite in the appropriate proportion. Compacting the milled mixture, followed by sintering at lower temperatures by a margin of at least 400.degree. C., will produce very strong dense carbides at low cost. The method may be extended to include metal based composites, which also includes cermets, by incorporating an appropriate excess of metal powder(s) in the starting materials.