Abstract: A pivot joint has a first structure comprising a ball mounted in a receptacle, wherein the location of the ball is held with respect to the receptacle, and a second structure mounted on and movable with respect to the ball, wherein the second structure has at least one bearing surface which defines its position with respect to the ball. The ball may be held in location by contact with the receptacle at at least two positions. At least one of the positions of contact may be adjustable.

Abstract: Apparatus for aligning an optical measuring system to a desired direction comprises two housings (42,48) attachable to two relatively movable parts of a machine. The housings (42,48) have engagement means (53) such that when they are engaged together the optics inside (44,50) are aligned. The first housing (42) may be provided with attachment means, such as a ball (46), which may be located in a mount (54) on the machine table (56). The position of this ball (46) is determined and the machine spindle (60) is moved to a position a distance from the ball (46) of the first housing (42) to enable attachment means (52) of the second housing (48) to be attached to the spindle (60) when the two housings (42,48) are joined and such that the apparatus is aligned with the desired direction. The engagement means (53) between the two housings (42,48) may be compliant along an axis of the apparatus.

Abstract: A measurement probe (10) has a stylus part (12) connected to it by means of a ball and cup universal joint (24/25 FIGS. 2 and 3) The stylus part (12) is reorientable relative to the probe and during reorientation is held by means of magnetism or suction to an at tractor (50) whilst the probe (10) is moved. The stylus part (12) is held in static relation to the probe during measurement by means of magnetism or vacuum. The stylus part (12) may be exchanged for another, e.g. 12a or 12b′ at rack (100). During exchange the magnetism or vacuum holding (15) the probe and stylus part in static relation is reduced.

Abstract: A bearing arrangement for an articulatable support (6) comprises bearing assemblies (20/28, 22/29, 24/30 and 26/32). In one embodiment the assemblies comprise a ball (20, 22, 24, 26) and aperture (40 FIG. 2) having sliding contact at discrete areas (36) during relative rotation. In another embodiment the sliding contact may be formed at a ball (20, 22, 24, 26) and a plastics e.g. P.T.F.E. support (84, 85 FIGS. 10 and 11). Resilient displacement of the bearing contact along a rotational axis (A and B) is provided by planar spring supports (28, 32) and rigid support is provided by supports (29 and 30).

Abstract: A mower (100) has a collecting box (108,110;1) with the dual functions of collecting mown grass and distributing grass or other material over the ground. Thus the box has an outlet opening (12) which is closed or obstructed during grass collection. It may be an elongate opening which is obstructed by an elongate brush (2) or paddle (8) member which is rotatable when it is desired to discharge material. The box may have a mechanism such as a belt or other conveyor (10;11;12) for conveying material to the opening.

Abstract: A bevel gear assembly for transmitting high horsepowers between a first shaft and a second shaft the axis of which lies at an angle to the first shaft includes a main bevel gear mounted on the first shaft and having two circumferential rows of teeth. The teeth face axially in opposite directions and a pair of secondary bevels are provided meshing respectively with the two rows of teeth. The secondary bevels are coupled to drive the second shaft.

Abstract: The stylus of a work piece measuring probe is supported for movement in three dimensions by three pairs of leaf springs connected in series and arranged as if lying at the six sides of a rectangular box.

Abstract: In a work piece measuring probe the movement of a stylus in three dimensions is sensed by respective inductive transducers having sensing coils fixed to a support in positions adjacent three mutually perpendicular surfaces defined on the stylus.

Abstract: A by-pass gas turbine engine capable of producing an unmixed exhaust stream which comprises a core of hot turbine exhaust gases surrounded by an annular layer of by-pass air, is combined with a target thrust reverser. The ratio of the total pressure of the by-pass air to the total pressure of the turbine exhaust gases is arranged to be greater than unity to a significant extent, and the buckets are made from lightweight materials such as titanium, light alloys or even fiber re-inforced composite materials.