Patent GB-189717434-A (GB)
Title: Improvements in Electro-mechanical Devices for Producing Corresponding Positions in Transmitting and Receiving Apparatus.
Inventor: BARR ARCHIBALD
Filed: 1897-07-24
Granted: 1898-07-16
Abstract: 17,434. Barr, A., and Stroud, W. July 24. Signals, electric and reply or tell-tale; recording signals.-A transmitter and one or more receivers are constructed so that pointers or other parts in them assume corresponding positions on dials or otherwise. Fig. 1 shows a developed section of a transmitter in which the case A is rotatable on abase B by a handle, to place a pointer P over any part of the edge of a marked dial D. The glass top E of the case carries a central metal ring F, divided by insulating-material into two semicircular halves, which are connected through two separate electromagnets, such as U<2>, with a battery and a brush L, bearing on either half or an insulating part of the ring F. This insulating part is opposite the pointer P in the case A. The brush is carried by a shaft N, coaxial with the ring F and carrying a bevel-wheel Y in gear with two loose wheels X<1>, X<2>. These tend to rotate in opposite directions under action of a spring barrel M and shaft, but they are geared separately to shafts G provided with arms which are normally detained by the armatures V<2> of the electromagnets U<2>, the brush L being on the insulating-segment of the ring F, so that no current passes. When the case A is turned with the ring F, this makes contact with one part of the ring, exciting a magnet U<2>, and freeing one shaft G and wheel X<1> or X<2>, which then rotates the wheel Y and shaft N in one direction or the other until the brush L again comes on the insulating part of the ring F, when the parts are stopped by the armature V<2>. One shaft G thus makes a number of rotations depending on the amount of rotation of the case. Each shaft G carries a contact-maker, such as I<2>, which closes the circuit of a battery to line once in each revolution. The speed of rotation of each shaft is limited by a centrifugal friction governor G<2>, or an air fan. The shaft N carries a pointer H. The receiver is of similar construction. The line currents pass through two electromagnets having armatures which allow the rotation of a shaft such as N with its pointer over a dial. The ring F and brush L are not required in the receiver, and the contact-maker I<2> may also be omitted, or may be retained to send currents back to a receiver at the transmitting- station, indicating what signals have been received, or such return currents may operate the magnets U<2> of the transmitter. The line currents may also operate a call bell or bells, In a modified transmitter, the brush L, ring. F, and two electromagnets U<2> are replaced by mechanical apparatus, Fig. 15, for operating two detents V<1>, V<2> for the shafts G. The shaft N carries two levers with rollers L', L<2> moving on a cam-ring F<1> and connected with the detents V<1>, V'. One half of the ring is elevated, so that, when the ring is turned by the handle, one detent is moved, and frees the corresponding shaft. The transmitter and receiver dials may be marked with any desired words, for use as ships' telegraphs or other signalling. The divided ring F may be geared to a rudderhead, to automatically indicate the position of the latter on the receiver dial. The rotatable brush L may be replaced by a brush movable in a straight line by a nut on a screw-threaded extension of the transmitter shaft N, and the ring F by a movable divided straight bar. The pointer of the receiver may be replaced by a pencil movable similarly by a screw, and marking on paper on a drum, which rotates uniformly or after each signal. The transmitter handle; ring F, brush L, and magnets U<2> may be dispensed with by operating the two detents V' directly by hand, so that the transmitter pointer H moves to the desired place on the dial D ; or the two electromagnets U<2> may be controlled similarly by hand-switches. Separate line-wires may be used for the two contact-makers I<2>; the number of wires may be reduced by arranging the contact-makers to send opposite currents to one line-wire, and providing the receiver magnets with polarized armatures. In some cases, the movements in the instruments may be in one direction only. The driving-gear M may be modified. The drum and shaft may be toothed to rotate a dial and pointer, as a winding-indicator. The power may be taken from two separate springs, or by differential gear from only one end of a single spring. Springs may be replaced by weight, electric, or other motors. Other escapements than the arms and detents V<2> may be used. Two sets of apparatus may be used for signalling deflections or a deflection and a range from two positions to a third one. The receivers may be placed so that their deflected pointers cross and indicate directly on a third movable bar, which is graduated and moves over a graduated arc, giving range and training for a gun directly.