Abstract: The size of the spiral gaskets which are formed by winding a sealing strip and a compressible filler strip around a mandrel is controlled by measuring the angle through which the mandrel turns, e.g., by means of an encoder. The lengths of arcs on the periphery of the gasket as it is wound around the mandrel are also measured, e.g., by means of a wheel running on the periphery of the gasket and an encoder counting turns of the wheel. The arcs are defined by the angles through which the mandrel turns. The supply of strip is terminated, e.g., by cutting the strips, as result of an arc achieving a particular length.

Abstract: A thermal radiation baffle for apparatus for use in directional solidification of crystalline material, to be mounted at one end of a furnace, and to allow a mould containing the material in molten form to pass through, has at least one clamped layer of interconnected flexible strips of refractory material. Each such layer has an ordered construction, for example, with the strips being interwoven, or knitted; and has one or more slits therein. At least substantially the whole of each slit is inclined at a significant angle to the strips, so that the strips do not become detached or worn in use, but the layer is capable of resiliently engaging the sides of, for example, an irregularly shaped mould. A slit may be provided between two separate, but adjacent, pieces of the layer.

Abstract: A plain bearing material, e.g. for a bearing bush or a thrust washer has a composition of 45 to 60 weight percent of semiaromatic polyamide, 15 to 20 weight percent of glass fibre, 10 to 20 weight percent of graphite, 10 to 20 weight percent of polytetrafluoroethylene and up to 5 weight percent of silicon oil.

Abstract: Dispersions of sinterable powder, for example, of metal or high-melting-point non-metal such as silicon, or a ceramic substance such as silicon carbide, silicon nitride or alumina, are hot injection-molded using a dispersion of the sinterable material in a binder which, like the dispersion, is solid at room temperature and fluid at the temperature of molding, forming a molded product of uniform density. The binder employed contains polystyrene, which forms the predominant weight proportion of the binder, and in lower weight proportion, an organic compound, e.g., diphenyl carbonate, which is solid at room temperature, is soluble in the molten polystyrene, and is more soluble than the polystyrene is in a lower aliphatic alcohol or ketone. After molding, the binder is removed in non-solid form as vapor, or by dissolution in a solvent, or by oxidation to volatile materials, to leave a porous structure of uniform density.

Abstract: A camshaft (10) is formed from a plurality of individual chill cast cams (12) and an elongated shaft (24). Each cam (12) has a hole (20) therethrough which has a groove (22) in its surface at a predetermined angular position. The shaft (24) has a plurality of cam receiving portions (24a) thereon which are spaced along the shaft and each have an outer peripheral surface (26) which is a close fit in the hole (20) in one of the cams (12). The outer peripheral surface (26) has a groove (28) therein at a predetermined angular position. The grooves (22,28) cooperate in forming a passage (30) which receives a wedge member (32) to hold the cam (12) in a fixed orientation relative to the shaft (24).

Abstract: A method and apparatus are described for the production of piston castings, and, in particular, a die construction and method of use thereof are described, the die having a crown forming part (18) separable from a skirt forming part (12). In the method, when solidification of the casting occurs to an extent at least enabling the separation of the skirt forming die part therefrom to be allowed, and the die parts (20, 22) are separated, the casting is retained by the crown forming part (18) of the die. After a subsequent process step, such as the solidification of the remainder of the piston casting, and or the cooling of the piston casting by an air blast (64), the solidified piston is removed from the crown forming part of the die.

Abstract: A heat shield (10;40) comprises one or more metal members (14,24;44,46) defining a rigid enclosure (12;42) having a substantially continuous heat-reflecting surface (26 or 32; 50 or 52). The shield also comprises a plurality of sheets (30;48) of smooth flexible metal foil within said enclosure. The sheets are arranged one above the other, extend generally parallel to the heat-reflecting surface, and are free to touch one another.

Abstract: The roughness of an area of the surface of a workpiece (W) is measured by bringing a height measuring device (10) to points on the surface and using the device to measure the height of each point relative to a datum level defined by a skid (17) while the device (10) is stationary relative to the surface. The points are arranged in a repetitive pattern in two dimensions across the area. The movement between the points is brought about by orthogonally arranged stepping motors (20,22).

Abstract: A piston, e.g. for an internal combustion engine, comprises a crown (16) and a skirt (12). The skirt (12) has an aperture (22) in which an insert (14) of a different material from the remainder of the skirt is secured. The insert (14) may be of plastics material injection moulded into a metal skirt. The insert (14) provides a plurality of pads (34) which extend from a thrust surface of the skirt so that the pads can transmit lateral forces and cause lubricant to be forced over the pads by hydrodynamic action during reciprocation of the piston.

Abstract: Bearings having an overlay (14) deposited by cathodic sputtering. In one example the overlay comprises an aluminum matrix (22) containing a dispersed phase (24) of tin. The overlay may contain a relatively low content of tin adjacent the interface (18) with the substrate (10;12) rising to a relatively high content at the surface. The surface may comprise a layer (26) of substantially pure tin to act as a sacrificial overlay during initial running of the bearing.

Abstract: A piston comprises a crown (12) and a skirt (20). At least a portion of the skirt (20) is formed of a ceramic material injection moulded directly on to the remainder of the skirt (20) or the crown (12). The ceramic material provides a plurality of pads (24) which projects from a thrust surface of the skirt (20) to transmit lateral forces against a wall of an associated cylinder.

Abstract: A tool (14,15) for use in working a surface of a non-metallic material having a Vickers hardness value up to 5000 is made up of a layer of platelets (28). The platelets form a working surface (20,21) which is complementary to the required shape. The platelets (28) adjoin one another and present a substantially continuous surface. Each platelet is made of a composite material having a composition comprising silicon carbide, and a material selected from the group comprising gemstone powder, and synthetic diamond powder.

Abstract: A method and apparatus are described for controlling the rate of pouring of molten metal. Examples are given of pouring metal onto a steel strip to form a coating having a uniform controlled thickness thereon. The method comprises the use of an intermediate holding dish having pouring means in the form of a generally vertical slot. The metal head presented to the slot is variable in response to signals from sensors measuring, for example, total strip thickness and the metal level within the holding dish. Signals from the sensors are also used to generate control signals to vary the rate of pouring from a holding furnace into the dish.

Abstract: The piston comprises a crown (12), and a skirt 30 made of plastics material secured to the crown. The crown (12) is formed integrally with a depending boss (16) arranged to receive a gudgeon pin (18) by which the piston is connected to a connecting rod (24). The skirt (30) encircles the boss (16) and is spaced therefrom.

Abstract: A method is described for the production of a porous ceramic body and the subsequent infiltration of the body with a molten metal to produce an article having a reinforced metallic matrix. The article may be further worked by known techniques such as extrusion or forging, for example.

Abstract: Cylinder head gasket which includes between adjacent cylinder bore apertures a heat-conductive element which is in thermal contact with the metal eyelets of those apertures and extends into a coolant aperture of the gasket.Such a gasket is less liable to failure through non-uniform heating during engine operation.

Abstract: In one method of cross-grinding in accordance with the present invention a non-planar surface on a workpiece, of a non-metallic material having a Vickers hardness value up to 5000, comprises, in each of two grinding steps, traversing the rotational axis of a grinding wheel along a predetermined axis, relative to the workpiece surface. In the first step the radially extending plane of the grinding wheel includes the predetermined axis, and the required workpiece surface is produced with inevitable ridges. For the second grinding step the working surface of the same, or different, grinding wheel is shaped by a tool capable of shaping in a normal manner the working surface suitable for the first grinding step. However, the working surface of the grinding wheel is altered by the radially extending plane of the wheel when presented to the tool being inclined in one sense at a selected angle, in the range 1.degree. to 20.degree.

Abstract: Intumescent sheet material having a matrix whose predominant ingredient is an unfired kaolinitic clay comprising ball clay reinforced by inorganic vitreous fibre (for example, mineral wool) contains heat-expandable graphite as intumescent agent and up to 10 percent by weight of an organic binder. It is made by dewatering an aqueous suspension of the aforesaid ingredients in the form of a layer which includes cellulose fibre as web-forming agent.

Abstract: A method and apparatus are described for controlling the rate of pouring of molten metal. Examples are given of pouring metal onto a steel strip to form a coating having a uniform controlled thickness thereon. The method comprises the use of an intermediate holding dish having pouring means in the form of a generally vertical slot. The metal head presented to the slot is variable in response to signals from sensors measuring, for example, total strip thickness and the metal level within the holding dish. Signals from the sensors are also used to generate control signals to vary the rate of pouring from a holding furnace into the dish.

Abstract: It is known to obtain from a sinterable powder (e.g., of silicon nitride+metallic oxide sintering aid) a shaped article with at least 95% theoretical density, by the hot isostatic pressing of a preshaped body of the powder while that body is encapsulated in a gas-impermeable capsule which is plastic at the temperature of the hot gas by which the isostatic pressure is applied. Until now, a pressure of the order of 100 MPa has been treated as the practical minimum necessary for hot isostatic pressing. By the invention, a pressure less than 20 MPa is used, in conjunction with a degassing of the preshaped body, carried out prior to encapsulation, as in a vacuum whose pressure is no more than a few mm of mercury, and preferably less than 1 mm (approximately equal to 0.15 kPa).