Patent GB-279510-A (GB)
Title: Apparatus for electrically transmitting to a distance the indications of a measuringinstrument or the like
IPC: G08C19/22
Filed: 1927-10-24
Abstract: 279,510. Deutsche Telephonwerke und Kabelindustrie Akt.-Ges. Oct. 23, 1926, [Convention date]. Tell-tale apparatus. - In apparatus for transmitting to a distance the indication of an instrument A, Fig. 1, a testing device F moves cyclically over the dial of the instrument and operates a contact at a fixed point in the cycle and also upon finding the pointer, the synchronously moving pointer S, Fig. 2, of the receiver being started by the one contact and stopped by the other. In the arrangement shown, the feeler F driven by a motor M1 engages a contact a fixed at one end of the scale, thereby energizing a relay R1 which locks up over contact 2 and opens at contact 4 a short circuit around a source of high-frequency current HFS connected to line L. The relay R1 also closes at contact 3 the circuit of a brake b, which holds the pointer Z. When the feeler F engages the pointer Z, relay R2 opens the locking circuit of relay R1, thereby short-circuiting the source of current HFS after a period determined by the reading of the instrument A. At the indicating station, the energization of relay R3 causes a clutch magnet K1 to rotate an arm e, which normally rests at the end g of a slot in the disc h, thus moving the pointer S over the dial. When the relay R3 de-energizes, a clutch magnet K2 rotates an arm r, which normally rests at the end i of the slot, to the other end of the slot where it closes a contact g in the circuit of a relay R4 which locks up over contact 10 and disconnects the clutch magnet K2. During this movement the member r returns the member e to its normal position, and also, if the pointer S had previously given a larger indication than that to be indicated, moves the pointer S back until the arm r. engages the arm e. To facilitate this operation the arm r carries a pivoted catch adapted to be operated by a plunger slidable in the end of the arm r. Several indications may be transmitted simultaneously over the same line wires by using different frequency currents. The Specification as open to inspection under Sect. 91 (3) (a) comprises also an arrangement wherein the indicator shown in Fig. 2 may be replaced by an arrangement, Fig. 4 (Cancelled), (not shown), in which the relay R3 closes the circuit of a heating' resistance which heats a thermopile in series with an ammeter, the current produced by the thermopile depending on the duration of its heating. That Specification also states that the feeler may consist of a wheel with a rubber rim running over the scale of the instrument, or. to avoid mechanical action upon the pointer, the testing may be effected by magnetic or electrostatic means, the pointer being made of magnetic material or provided with a capacity surface or inductive winding. Alternatively the pointer may have a sharp edge to form one terminal of a spark gap, or may carry a screen or mirror for a selenium cell carried by the feeler. The line to the receiving instrument may be connected successively by a switch to the feelers of several instruments. The rotations of several instruments may be added on a single receiver, the indication of which may be transmitted to a distance. In a modification, the fixed contact may be arranged at the other end of the scale so that the feeler engages the pointer before the fixed contact. A spring controlled pawl arrangement, Fig. 3 (Cancelled), (not shown), carried on the arms r for controlling the pointer s and arm e also is described. This subjectmatter does not appear in the Specification as accepted.