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Gersan Establishment

David Antony Homer

William J Turner

Andrew D Stewart

Eryk Stefan Doerman

Ian M Clarke

Timothy James Osgood

Ewan Howden Croucher

David William Beal

Eric Jozef Blondeel

Peter Armstrong Aked

For blocking or polishing a natural or synthetic stone having a Mohs hardness greater than about 5, a blocking head has a body, a mounting member which can move vertically with respect to the body, and a rotary spindle driven by a motor. The mounting member is carried by a leaf spring whose position is altered by a parallel linkage whose arm is driven by a motor. In this way, the spring can for soft landing apply an upwards bias opposing the gravitational force of the mass of the mounting member. When the stone is in contact with the scaife, the deflection of the spring measures the force on the stone, and this deflection is detected by an LVDT. Subsequently, the spring can apply a downwards bias to augment the working force. A microprocessor is responsive to the output of the LVDT and controls the motor so that the force applied to the stone complies with a predetermined program.

Working a natural or synthetic hard stone such as a gemstone

Controlling a feed of objects

To weigh objects in quick succession, the objects are projected with a known horizontal velocity onto a ramp which has a surface which curves down through 90.degree.. The ramp can move horizontally in response to the impulse corresponding to the change in horizontal momentum of the object. A transducer senses the movement of the ramp and the output horizontal velocity of the object is sensed, enabling the change in horizontal velocity to be calculated. The mass of the object is calculated from the horizontal movement of the ramp and the change in horizontal velocity of the object. In order to obtain accurate sensing of the movement of the ramp, the transducer is a linear variable differential transformer having a primary winding energized by a cyclical carrier signal and two matched secondary windings in series; the secondary winding output signal is rectified to a corresponding DC voltage having ripple components, and a sample is taken of the signal at the zero voltage of the principal ripple component.

LVDT displacement sensor with signal noise reduction for use in weighing

Weighing a number of objects in succession

Growing community of inventors

Maidenhead, United Kingdom

David Antony Homer