Patent GB-857230-A (GB)
Title: Improvements relating to recording apparatus
Inventor: LOBELLE MARCEL JULES ODILON
IPC: G01R31/14
Filed: 1958-06-12
Abstract: 857,230. Recording-apparatus. M.L. AVIATION CO. Ltd. Sept. 11, 1959 [June 12, 1958], No. 18893/58. Class 106 (4). [Also in Group XXXVI] Apparatus for recording in succession the alternative states of a number of electrical circuits or components comprises a cylindrical container 1, Figs. 1, 3, provided at one end with a screwed connector 2 for a multi-pin plug for connecting the circuits or components to be tested. The other end is fitted with a screwed end cap giving access to the recording device, which comprises a driving-mechanism for a strip 4 of voltage-sensitive paper and two spring- mounted styli 5, 6. The strip 4 is withdrawn from a spool 7, passed over a guide 8 and jockey roller 9 and is wound on to a take-up spool 10 mounted on a driven shaft 11. To facilitate removal of the strip 4 the styli 5, 6 are mounted on a spring-loaded member 15 sliding radially in a groove 16, which in the absence of the end cap is forced outward so as to disengage the styli; the end cap engages a chamfered surface 17 on member 15, causing the styli 5, 6 to come to bear on the strip 4. The jockey roller 9 completes the electrical circuit from the styli 5, 6. The circuits or components to be tested are each connected to one of the fixed contacts A-K. Fig. 5, of a rotary selector switch 20, an additional contact 21 of which is connected to the wiper 22 and also to the coil of a relay 23 having changeover contacts 23a, 23b. According to the state of the circuit under test the relay is or is not energized to complete a circuit to one of the styli 5, 6. The styli are supplied from a tertiary winding 25 of a transformer 26, the primary and secondary of which form the coupling circuit of a transistor oscillator 28. The wiper of the selector switch 20 is mounted on the same shaft 11 as the take-up spool 10, being driven by a rotary solenoid having a coil 35 which rocks an armature and rotates the shaft 11 through a ratchet-stepping mechanism. A conducting disc 36 is also mounted on the shaft 11 and at the start of a cycle of operation it and the wiper of the switch 20 are in the position shown. Operation is initiated by a pulse between conductors 37 and 38 which operates relay 39 to close contacts 39a; this completes a circuit through coil 35 via contacts 40, which open when the armature rocks, the armature being held in position by the reduced current through resistor 41. Resistor 42 and condenser 43 cause the relay to remain operated for a definite time interval. Operation of the solenoid advances the chart strip 4 and the wiper 22 of the selector switch one step; the disc 36 is also turned through a step and completes a circuit from conductor 45 via line 46 to the coil of a stepping relay 47 with contacts 47a, 47b. This relay takes over control of the rotary solenoid, relay 39 only controlling the start of a cycle of operation. Operation of relay 47 closes contacts 47b to operate solenoid coil 35 and breaks contacts 47a of its own operating coil ; condenser 48 however discharges through relay coil 47 when contacts 47a open, rendering relay 47 slow to release so that solenoid 35 is operated for a definite time interval, at the end of which it is de-energized, contacts 47a remake and the cycle is repeated. At the end of a complete cycle gap 50 in the disc 36 comes opposite contact 51 and breaks the current to relay 47, thus terminating the stepping action, which can only be restarted by a fresh pulse between conductors 37, 38. To indicate the start of a cycle contact A may be taken to a small condenser, the current through which, in position A, energizes relay coil 23, causing " on " stylus 5 to mark the strip 4; this current does not flow all the time, so that for part of the time coil 23 will be de-energized and the " off " stylus 6 will mark the strip; thus at the start two marks are produced side-by-side.