Cranfield Institute of Technology

Elite Townshend, Ltd.

Jack Dinsdale

John Loxham

David W Parkins

Robert S Berks

Geoffrey Vorley

John P Hardwick

David Wallace McQue

Apparatus for correcting or compensating for the tracking error of the pivotally mounted (1) tone arm (23) of a phonograph includes a first intermediate member (9) to which said tone arm (23) is pivotally (1) connected, a second intermediate member (12) which is rotatably connected to the first intermediate member (9) by a belt (18) and pulleys (13) which are sized in such a way that a photodiode source (21) and a photodiode detector (22) both carried by the second intermediate member (12) will tend to be indirectly moved by a motor to maintain them substantially constantly in register with a point on the tone arm (23). A slotted mask (24) carried by the tone arm (23) is interposed between the source (21) and the detector (22) and its slot defines a central 'null' position in which said motor will not be driven when the required relationship exists. Deviation in either direction will cause the motor to be driven to re-establish this relationship. An insignificant maximum tracking error below 0.1.degree. can readily be attained. Other constructions in which the second intermediate member (12) is omitted and in which the means to control operation of the motor are differently constructed and arranged are described and illustrated.

Phonograph

A phonograph has a viscous damping arrangement coupling a pick-up arm to the base of the phonograph to damp vertical and horizontal vibrations of the arm. The damping means is coupled to the arm at a position close to the pick-up cartridge of the arm. A counter-balance mass is also provided on the arm, the mass having an adjustable position and mass.

A control system for a grinding machine or other machine tool, wherein desired workpiece profiles are stored in a digital computer which controls the position of a tool in relation to a workpiece in accordance with the stored profile and in accordance with the position of a workpiece profile follower to compensate for tool wear.

Computer-controlled machine tool

A machine for forming gears and the like comprises a workpiece support continuously rotatable about a first axis, a tool support angularly displaceable about a second axis and constructed to support a tool for rotation about a third axis angled to the first axis and an electrical master-slave servo system having a master providing a first electrical signal defining a required angular displacement for the tool support and a second electrical signal for influencing the continuous rotation of the workpiece support in dependence upon the angular displacement defined by the first signal.

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Harrold, United Kingdom

Jack Dinsdale