Abstract: A fuel metering system having a fuel pump operable to supply fuel at high pressure to a metering valve from which metered fuel is fed, in use, via a pressure raising valve to a gas turbine engine, a spill valve connected between the high pressure (HP) supply upstream of the metering valve and low pressure (LPp), and a restrictor device connected between the spill valve and low pressure (LPp), the pressure (LPf) arising at or upstream of the restrictor device, which varies according to spill flow through the device from the spill valve, being applied to the pressure raising valve, such that the pressure required to open the pressure raising valve varies in response to the amount of fuel spilled by the spill valve.

Abstract: Multi-faceted rotating optical scanning system having facet angle corrector means for reducing banding in imagery produced therewith. In accordance with the invention, the corrector means comprises a corrector plate supporting a plurality of transparent discs, each one of said discs being positioned in advance of a different facet of said scanner. Each of the discs is further designed to have a slight wedge angle between its two surfaces such that by independently rotating each disc, a light beam passing through it can be bent by a precise amount to control the angle at which the beam impinges upon the associated facet, and, hence, the angle at which it is reflected therefrom onto an image receiving medium. This system thus permits any banding that might otherwise be caused by relative differences in the angular orientation of each facet to be essentially eliminated in a highly accurate, inexpensive manner.

Abstract: A validator for a card bearing a code readable by moving the card forward past a reader, particularly for use in a vendor to control vending, in which the card is transported forward from an entry position past the reader to an escrow position. If read as valid, the card is maintained in the escrow position pending the user's decision to have the card collected or to obtain return of his card. If the card is read as invalid, it is immediately fed back to the user. The card transport is such as to prevent a valid card from being pulled back out of the validator as by a string or tape attached to the card, and the validator is so constructed that it is easily opened for servicing, including removal of a card which may become jammed in the validator.

Abstract: Apparatus for validating a card having positioned thereon a plurality of redundant encoded blocks of data readable by moving the card past a reader and for controlling the movement of such a card whose validity is to be determined. A card transporter moves a card along a predetermined path. A reader senses each block of data on the card as it moves forward along the path from an entry position to a dwell or escrow position and supplies an electrical signal representative of the data in each block. A card validator responsive to this signal compares data derived from at least one block thereof with a preselected set of data in making the validity determination. The validator includes circuitry for combining the data from at least one block with a prior set of data to produce a stored resultant set of data, and for comparing it with a preselected set of data and for supplying an indication of card validity if these sets of data are identical.