GB1269365A - Control arrangement, e.g. for an electronic lock - Google Patents

Abstract

1,269,365. Locks. T. G. HESSELGREN. 6 May, 1969 [7 May, 1968], No. 23151/69. Heading E2A. [Also in Division G4] A control arrangement comprises individual inputs to which can be applied respective pulses, a series of electronic elements, each other than the first coupled to the preceding one and all coupled individually to the inputs, each element having an output to carry a signal indicative of a particular state of the element, an operating circuit responsive only to all of the outputs simultaneously carrying their said signal, the arrangement being such that this can only occur on the application of pulses to said elements in a predetermined sequence, and a fault circuit coupled to the elements and arranged to be responsive to the application of pulses in a sequence other than said predetermined sequence. In the control arrangement shown which is part of an electronic combination lock a plurality of push buttons are provided some of which are individually connected to the respective inputs of the electronic elements which as shown are monostable multivibrators, the arrangement being such that when the push button connected to the first multivibrator of the chain is depressed, a pulse is applied to the multivibrator, which is differentiated by a resistor-capacitor combination cr so that its negative going edge turns on the first transistor T1 of the first multivibrator this in turn turns on the second transistor T2 of the first multivibrator which produces a negative going pulse at its emitter; this is applied to the second multivibrator to prepare it so that when the push button connected to the second multivibrator is depressed, the negative going edge of the pulse so produced, can turn on the second multivibrator which produces a positive pulse which prepares the third multivibrator, the process being continued until all the multivibrators have been turned on; the output pulses of the multivibrators are applied to a gate GLB which is of the AND type so that it is only operated when pulses are received that all its inputs, the gate in turn operating transistors T19, T20 which control a bolt solenoid (not shown); each of the multivibrators is associated with a respective gate Ga, Gb, Gc, Gd, and all of the gates Ga to Gd are connected to a gate GLA of the OR type the output of which is connected to an alarm circuit; all of the push buttons are connected in parallel via diodes to paralleled inputs Yl, Y2, Y3, Y4 of the gates Ga to Gd the arrangement being such that depression of any push button sends a positive going pulse to the gate which passes the pulse to the gate GLa which in turn passes the pulse to the alarm circuit to operate it; the alarm operates unless the input pulse to each of the gates Ga to Gd is neutralised by a pulse applied to the appropriate gate by the push button associated with the multivibrator. Each multivibrator uses complementary transistors and the gates Ga to Gd use pairs of cascaded NPN transistors; the alarm pulse is applied to the second transistor of each pair T10, T12, T14, T16, and turns the transistor on so that a negative going pulse appears on the line Q1 to Q4 connecting the transistor to the gate GLa which consist of a transistor T17 and parallel resistors. The inhibiting pulse from the correct push button is applied to the input W1 to W4 of the appropriate input transistor T9 to T15 of the gates Ga to Gd and turns the transistor on with the result that its collector earths the base of the second transistor of the appropriate gate T10 to T16 so that the alarm pulse is neutralised. The first multivibrator has a connection X1Z2 to the gates Ga and Gb the second multivibrator has a connection X2Z3 to the gates Gb and Gc the third multivibrator has a connection X3Z4 to the gates Gc and Gd and the fourth multivibrator has a connection X4 to the gate Gd to prevent alarm pulses on inputs Y2, Y3, Y4 turning on the alarm.