Abstract: A chain drive comprises a chain having a plurality of articulating chain links and a toothed sprocket. The sprocket and the chain links have bearing surfaces that contact one another during meshing of the chain. The surfaces are disposed along the length of the chain between the apertures and to one side of a sprocket tooth. One of the bearing surfaces is arcuate so that during meshing of said chain link the bearing surfaces are brought into contact such that the instantaneous centre of rotation of the meshing chain link passes from the first pivot pin of a link to the point of contact of the bearing surfaces before passing to the second pivot pin of the link. This reduces the noise generated by collision of the chain links and the sprocket teeth.

Abstract: The link plates, bushes or rollers of a transmission chain are treated so as to produce a surface layer of iron bisulphide. The surface improves the resistance of the chain to wear and also accelerates the running-in process.

Abstract: A chain such as these used in a fork lift truck carriage lifting mechanism has a plurality of interleaved link assemblies each having a pair of outer link plates and a plurality of intermediate link plates. The outer link plate has a strength less than that of any intermediate link plate when measured in an unassembled state. The reduced strength may be achieved by a reduction in thickness or head area of the link plate. The outer link plates may have a stiffness of 60% to 90% of the average stiffness across the chain and a first group of intermediate link plates of certain chain configurations have a stiffness of 70% to 90% of the average stiffness of the chain. The invention provides for a chain in which the load is more evenly shared between link plates and allows a single composite chain to be replaced by two smaller chains without loss of load capacity.

Abstract: A chain comprises inner link plates that are each connected to an adjacent outer link plate by means of at least one pin that passes through overlapping portions of the respective links. Outboard of the inner link plates the pin supports a rotary bush with a radially extending flange. The bush in turn supports one end of an outer link plate and a roller. The outer link plate is an interference fit with the bush and the roller is rotatable relative thereto. In use the rollers are supported on a guide rail as the chain moves. The location of the bush bearing and roller provides easy access for maintenance and lubrication.

Abstract: A drive chain has opposed pairs of inner link plated that are interconnected by cast outer links. Pins pass through aligned apertures in overlapping end portions of the inner and outer links. Each pin is fixed relative to the inner link. The outer link has open or blind bores that receive end portions of the pins in a pivotal relationship. A bearing area is defined between the outer surface of the pin and an inner surface of the outer link bore. The provision of a bearing area in the outer link makes maintenance and sealing easier.

Abstract: A drive chain comprises a plurality of inner links (1) interconnected by intermediate outer links and elongate pins (7) that are received in apertures in the inner and outer links. There is substantial clearance between the outer link and the corresponding inner links so as to permit flexion of the adjacent elongate pins in a direction substantially parallel to the length of the chain. The outer link may be in the form of a separate plate (6) or may be an integral part of the pins. In one embodiment the outer link is a crimped plate that offers resilience in the direction of the chain. The drive chains provide for shock absorption.

Abstract: A chain comprises inner and outer links that articulate relative to one another on pins. The outer link having apertures which receive said pin ends in such a way that the links are easily assembled or dismantled. The pin ends have a retention portion that defines a flat and a bearing portion disposed between the retention portion and the inner link and defining a bearing surface for the outer link. The aperture in the outer link has an arcuate edge and a flat corresponding to that on the retention portion. The bearing surface has an arcuate portion that provides a rotational sliding fit with the arcuate edge of the outer link aperture and a reduced portion that is undercut with respect to the retention portion.

Abstract: A drive chain has a plurality of links (1) each comprising a pair of opposed cranked link plates (2). Each link plate (2) has two connection apertures (7) and is connected to an adjacent link plate (2) by a pin (6) passing through overlapping connection apertures. An aperture (7) at one end of each link plate is fitted with a sleeve (11) in which said pin (6) is releasably engaged by means of a key connection. The sleeve (11) is connected to said link plate (2) by means of an interference fit with the respective connection aperture (7).

Abstract: A chain tensioner for tensioning a chain in a drive of an internal combustion engine comprises a piston displaceable within a chamber. The piston is biased by a compression spring so that it protrudes from the housing towards the chain to provide the tension. The chamber has an inlet connected to a supply of oil from the engine. The oil acts on each side of the piston with substantially the same pressure such that the piston is damped in both directions when moving in the chamber. The surface areas of the piston on which the oil acts may be substantially equal so that no tensioning force is supplied by the oil.

Abstract: A sprag clutch having inner and outer concentric races 1, 2 with sprags 3 pivotally located between the races 1, 2. A circumferential garter spring 6 locates over the sprags 3 to bias them to a wedging position. Relative rotation of the races 1, 2 in one direction causes a centrifugal force CF to act on each sprag 3 to pivot away from contact with the outer race 2. The center of gravity G of each sprag 3 is located radially inwards of its center of rotation C such that when the sprag 3 pivots the centrifugal couple CF increases to overcome the increased tension couple SF of the garter spring to allow a snap action lift off of each sprag 3. The perpendicular distance of the center of gravity from the pivot center of each sprag increases during pivoting to cause an increase in the centrifugal couple. At the same time the perpendicular distance of the pivot point of action of the resilient mean from the pivot center decreases during pivoting.

Abstract: An infinitely variable phase adjuster for e.g. adjusting internal combustion piston engine valve timing by selecting the relative rotational positions of the engine crankshaft and a camshaft of the engine. Control is effected by adjusting a "lock" volume of oil on one side of a pressure fluid operable member displaceable to shift the phase.

Abstract: A hydraulic piston and cylinder machine includes a plurality of pistons and cylinders, a ring of ports for alternatively supplying fluid into, and for allowing the fluid to be discharged from each cylinder, and a cam having a plurality of lobes to control the displacement of the pistons in a cylinder block with respect to the progression of the cylinder block along the direction of the cam or vice versa. Each of the pistons traverses each of the cam lobes during a full rotation of the machine to undergo a number of piston strokes equal to the number of lobes. A control valve is adjustable to route working fluid discharged through at least one of the fluid discharge ports of the machine to the exhaust fluid outlet of the machine during each full rotation of the machine via an isolated pressure zone of the machine.