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Facit Aktiebolag

Spiralux Limited

Philip T Blenkinsop

Gerald Avison

Dexter R Plummer

John David Marsh

Robert J Needham

A control circuit for unlatching a door, particularly a pet door, includes a transmitter coil (L1), a pulse driver (11) for pulse energizing the coil, and a discriminator (12, 13) for detecting a.c. components in the coil current caused by currents induced in an outside tuned circuit brought adjacent the coil, e.g. around the neck of a pet seeking entry, and for comparing the frequency of the a.c. components with a standard. A latch drive circuit (14) responds to the discriminator for operating the door latch if the frequency comparison is satisfactory.

Pet door with control circuit therefor

A pet door comprises a frame hingedly supporting a flap undersized relative to the opening therefor in the frame; the resulting gaps therebetween are weatherproofed by sealing means in part constituted by co-extensive plastics magnet strips on confronting edges of the flap and frame. One magnet strip at least is mounted for movement in a direction across the gap into and out of face-to-face sealing contact with the other magnet strip, respectively as the flap enters and leaves its closed position; the movement is responsible for jam-free closing and opening.

Pet doors

A daisy wheel printer wherein a non-contacting sensor (24) is employed to detect the rotational position of the daisy wheel (10) by response to the interrupting action of the character stalks (12, 14) and to produce a train of pulses providing positional information in accordance with said interrupting action. In accordance with the invention, each stalk of the daisy wheel is divided by a longitudinal slit (26) into two or more branches (28, 20) thereby to increase the frequency of the interrupting action and, for a given rotation of the wheel, to cause the sensor to produce a train of pulses (32) containing a number of pulses which is an integral multiple of the number of stalks passing the sensor.

Daisy wheel printer

A method of reproducing characters or symbols in place of orthodox typing or printing comprises applying ink to successive points on the paper or other surface by means of a transducer forming a typehead, and building up each character by steering the transducer under the control of digitally stored information which may be selected from the store by a keyboard. The characters can be built up as a series of overlapping dots and each character may have a number of key points, the transducer moving along one of a limited number of pre-set paths from each key point to the next.

Growing community of inventors

Royston, United Kingdom

Philip T Blenkinsop