Method and apparatus for producing encoded electrical keys

Claim 2

Apparatus for encoding an electrical key of a kind that a person will momentarily apply to an electrical security system with a code operable to actuate the security system, and utilizing key blanks each having thereon a plurality of circuit paths interconnected by fusible elements, said apparatus comprising a key receptacle having electrical circuit paths insulatively spaced thereon in a spaced relationship corresponding to the spaced relationship of the plurality of circuit paths on the key blank so that the key blank when engaging the receptacle will place its corresponding circuit paths in electrical contact with corresponding individual circuit paths of the receptacle, an electrical power source, a temporary energy storage device coupled to said power source to be energized therefrom for storing electrical energy therein, circuit means for placing said power source and said energy storage device in electrical circuit relation with at least one of said circuit paths of said key receptacle, said circuit means normally being in open circuit condition, and including switch means operable to place said circuit means in closed circuit condition to apply the energy stored in said temporary energy storage device through said circuit means to said one circuit path of said key receptacle for burning out the fusible element associated with the circuit path of the key blank which corresponds to said one circuit path of said key receptacle and which is in electrical contact with said one circuit path of said key receptacle to effect encoding of the key blank.

Claim 3

ApparatuS as defined in claim 1 wherein said temporary energy storage device is an electrical capacitor.

Claim 4

Apparatus as defined in claim 1 including signaling means connected to said circuit means for signaling the electrical condition of the circuit paths of a key blank engaged in the receptacle.

Claim 5

Apparatus as defined in claim 1 wherein said circuit means include selection switching means adapted to select one or another circuit path of the receptacle for said circuit relation.

Claim 6

Apparatus as defined in claim 4 whwerein the selection switching means comprise an encoding network for automatically selecting a plurality of the circuit paths of the receptacle in accordance with a preselected code.

Claim 7

Apparatus as defined in claim 5 wherein the encoding network is a diode network arranged in accordance with a preselected code for selecting certain circuit paths in accordance with the code.

Claim 8

Apparatus as defined in claim 4 wherein said temporary energy storage device is an electrical capacitor and wherein an operation of the switch means provides a low impedance path for discharging the capacitor through said circuit means, the arrangement being such that the key blank when applied to the receptacle will provide a closed circuit through the circuit paths of the key and the corresponding circuit paths of the receptacle, so that the discharge of the capacitor acting through a selected circuit path of the key receptacle will cause the corresponding circuit path of the key blank to assume an open circuit condition.

Claim 9

Apparatus for encoding electrical keys of a kind that a person will momentarily apply to an electrical security system to actuate the system, and utilizing key blanks each having an insulative carrier on which electrically conductive distinct contact strips are disposed for engaging corresponding contacts of a security system when an encoded key blank is momentarily applied to the system, there being a common electrical conductor connected to each of the contact strips of the key by fusible means to form a multiplicity of individual closed circuit paths on the insulative carrier of the key blank, said apparatus comprising, a receptacle for receiving a key blank to be encoded and having a multiplicity of contacts each of which will be engaged by one of the contact strips of the key blank when the key blank is received thereby, a source of electric power sufficient to destroy a selected one of the fuse means on the key blank so as to place in open circuit condition a selected individual circuit path associated with the destroyed fuse means on a key blank to effect encoding of the key, circuit means for connecting selected ones of said receptacle contacts to said source of power, and selector switch means forming a portion of said circuit means operable to direct the power through selected combinations of contacts of said multiplicity of contacts on the receptacle to encode a key blank that may engage the receptacle with open and closed circuits that will be determined by the selected combination of contacts on the receptacle and which will determine a multiplicity of electric signals to be applied in a selected binary code combination by the key for actuating a security system.

Claim 10

Apparatus for encoding electrical keys of a kind that a person will momentarily apply to an electrical security system to actuate the system, and utilizing key blanks each having an insulative carrier on which electrically conductive distinct contact strips are disposed for engaging corresponding contacts of a security system when an encoded key blank is momentarily applied to the system, there being a common electrical conductor connected to each of the contact strips of the key by fusible means to form a multiplicity of individual closed circuit paths on the insulative carrier of the key blank, said apparatus comprising, a receptacle for receiving a key blank to be encoded and having a multiplicity of contacts each of which will be engaged by one of the contact strips of the key blank when the key blank is received thereby, a source of electric power sufficient to destroy a selected one of the fuse means on the key blank so as to place in open circuit condition a selected individual circuit path associated with the destroyed fuse means on a key blank to effect encoding of the key, circuit means for connecting selected ones of said receptacle contacts to said source of power, and selector switch means forming a portion of said circuit means operable to direct the power through selected combinations of contacts of said multiplicity of contacts on the receptacle to encode a key blank that may engage the receptacle with open and closed circuits that will be determined by the selected combination of contacts on the receptacle and which will determine a multiplicity of electric signals to be applied in a selected binary code combination by the key for actuating a security system.

Claim 11

Apparatus as set forth in claim 8 in which there are signalling means connected to a portion of said circuit means for signaling the electrical condition of the fuse means of a key blank engaged with said key blank receptacle, whereby to indicate the circuit condition of the respective contact strips of a key blank relative to the common electrical conductor connected to each of the contact strips.

Claim 12

Apparatus as set forth in claim 9 in which said source of power comprises a capacitor that stores the energy to open circuit a contact strip relative to the common conductor by destroying the fuse means interconnecting the common conductor and the associated contact strip on a key blank, and there being a circuit portion connecting said signaling meAns to a portion of said source of power in parallel relation to said capacitor whereby to indicate the condition of the contact strips of a key blank engaged in the key receptacle independently of the operation of said capacitor.

Claim 13

Apparatus as set forth in claim 10 in which said selector switch means have a portion movable to direct the power successively through one selected receptacle contact and another, said signalling means being connected to said selector switch portion to indicate successively the condition of each selected contact.

Claim 14

Apparatus as set forth in claim 10 in which said selector switch means comprise a plurality of switches connected each to one contact of said multiplicity of receptacle contacts, and said signalling means comprising lamps connected each to one of those contacts.

Claim 15

Apparatus as set forth in claim 10, in which said selector switch means comprise an encoding network acting automatically in response to a selected code applied thereto to direct the power to receptacle contacts that are determined by a further code.