Patent GB-1217622-A (GB)
Title: Control circuit, e.g. for electronic lock
Inventor: HESSELGREN TORE GOTTFRID
IPC: G07C9/00
Filed: 1968-02-13
Abstract: 1,217,622. Locks. T. G. HESSELGREN. 13 Feb., 1968 [16 Feb., 1967], No. 7113/68. Heading E2A. [Also in Division G4] A control circuit, e.g. for an electronic lock, comprises first and second source terminal means for connection to respective opposite poles of a supply of direct current, control terminals for supplying control current to control operation of a controlled member 78, a plurality of actuating switch means 0 to 9 coupled individually to said first source terminal means, a plurality of code step circuits sequentially coupled together by electronic relay means 41 to 45 and coupled to said second source terminal means and to selected ones of said actuating switch means to be actuated thereby and each before the last comprising chargeable means 20 to 24 arranged to be charged upon such actuation and so to precondition the next in sequence of said step circuits for such actuation, the last being arranged upon such actuation to operate semiconductor means of said control circuit in order to provide said control current at control terminals, and semiconductor discharge control means 28, 31, 34, 37, 40, 62, 63, 64 arranged to discharge said chargeable means of the code step circuits upon operation of any one of said actuating switch means not connected to the next in sequence of said code step circuits and to discharge said chargeable means upon operation of more than one at a time of said actuating switch means. In the control circuit shown each of the electronic relay means 4 to 45 is a transistor and each chargeable means is a capacitor and the arrangement is such. that when the capacitor 20 of the first code stop circuit is charged by the making of one of the switches the base of the first transistor 41 has its potential increased so that the transistor conducts which allows the capacitor 21 to become charged when second of the switches is made; the charging of 'the capicitor 21 applies a positive potential to the base 8 transistor 42 which allows capacitors 22 to be charged, the process being repeated until capacitor 25 is charged; when this happens a positive potential is applied to the base of transistor 46 which conducts and energizes the member 78. The energization of each transistor causes current flow through a resistor 60 common to the emitters of each of the transistors 41 to 45 and the potential developed across this resistor applies a positive potential to the base of the transitor 63 which thus becomes conducting, this in turn causes transistor 62 to become conducting and the voltage drop across an appropriate resistor 10 to 19 is such that the transistor 64 is held non-oonducting; should any of the switches be operated in the wrong order no potential is developed 'across the resistor 60 and in this event the transistors 62 and 63 remain non-conducting so that sufficient potential is applied to the base of transistor 64 to make it conducting and via the diodes 28, 31, 34, 37, 40 any of the capicitors 20 to 25 which are charged are discharged via the transistor. The current in transistor 64 causes the base of a transistor 65 to be made positive and the transistor 65 can then draw current to energize a solenoid 76 which operates an alarm. The member 78 is either a bolt-operating solenoid or a relay.