Patent GB-691471-A (GB)
Title: Electrically operated apparatus for summing the readings of indicating and recordinginstruments
Inventor: SPINK EDWARD WODEHOUSE
IPC: G01D1/16
Filed: 1949-10-26
Abstract: 691,471. Counting-apparatus. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Jan. 26, 1951 [Oct. 26, 1949], No. 27501/49. Class 106 (i). Electrically-operated apparatus for summing the readings of an indicating or recording instrument having a part which is periodically moved to and held in a position related to the value of the quantity being indicated or recorded, comprises a switch Q arranged to be operated by the instrument, the closing of the switch causing a step-by-step device S1 to take a position corresponding to the movable part, and the opening of the switch causing the actuation of means for generating pulses, corresponding in number to the value of the instrument reading and sent to a first counter M, the cessation of the pulses being determined by the device S<SP>1</SP>, and a second counter N registering the number of readings taken. The apparatus shown is associated with a temperature recorder including a movable drum G having contacts T around its periphery of which the one corresponding to the value recorded engages a fixed contact arm R. Alternatively, the contacts T may be fixed and the arm R movable with the drum. The contacts (except the one for zero) are connected to complementary contacts of a uniselector switch S<SP>1</SP> which is stepped by a magnet S. In operation, when a recording is being made, the switch Q is closed to energize a relay P which closes make-before-break contacts p<SP>1</SP> to energize a relay B and subsequently release winding II of normally energized relay A. Winding I is released by the transfer of contacts b1, b2, a circuit then being completed from battery F through contacts a1 magnet S, contacts b3, and an interrupter switch S<SP>1</SP>. The switch S<SP>1</SP> and magnet then coact to cause successive stepping of the uniselector S<SP>1</SP> until the wiper arm reaches the contact connected to R when switch S<SP>1</SP> is short-circuited through contacts b1, b2. Before the recording is completed, the switch Q is reopened and relay P de-energized. The release of contacts p1, p2 adds " 1 " to counters N and M respectively. Relay B is released but relay A is not re-energized since the wiper arm has left contact 1 of S<SP>1</SP>. The release of contacts b3 de-energizes magnet S to step S<SP>1</SP>, and energizes a slow-acting relay C which closes contacts c1 to energize a relay D. The closure of contacts d1 re-energizes the magnet S which then opens S<SP>1</SP> to de-energize C and therefore D. Contacts d1, d2 are then released, the latter adding 1 to counter M. This sequence of operations is continued for each step of the uniselector until the wiper arm returns to contact 1 when relay A is re-energized and the apparatus returns to normal. If the temperature is zero, relay A is not de-energized since, winding II is earthed through line V, and contacts T, R and b2. Counter M is not operated but 1 is added to counter N. Thus the reading on counter M divided by that on counter N gives the average value over a period. If the average of a sample of the values recorded is required, a timing switch is inserted at point Y or Z. In a modification, Fig. 2 (not shown), the counter M is replaced by a set of counters which are connected in turn under control of a point change-over switch of the recorder for registering the temperature values at different points. If the reading at any point is not required relay A is held energized through line V as described above.