Security control device

Claim 2

A security system for operation by any one of a plurality of persons each having an individual security device having a unique pre-determined arrangement of m first switch selector means, comprising: a plurality of second switch selector means arranged in n groups such that for each said pre-determined arrangement of first switch selector means there exists a mating unique predetermined arrangement of n second switch selector means, with each of the n second switch selector means in a different group; means accessible to said persons for controlling the selection of said second switch selector means; sensing means for simultaneously sensing the arrangement of first switch selector means of any one of the first security devices and for sensing any of said pre-determined arrangements of second switch selector means; a responsive circuit having at least two stable states and comprising p groups of at least two switching units per group responsive to the sensing means, each switching unit having a reSt state and an actuated state and being actuated by the sensing of a unique pre-determined mutually exclusive combination of x switch selector means, the responsive circuit being switched to a pre-determined one of its stable states only when any one but only one switching unit in each of the groups of switching units is in actuated state; wherein m, n, p and x are integers, x is greater than 1, ; wherein: any one of the mating arrangements of first and second switch selector means actuates one but one switching unit in each of the groups of switching units when said last-mentioned first and second switch selector means are sensed by the sensing means, the groups of switching units are connected in series, the switching units in each group are connected in parallel, each switching unit in a rest state is either a short circuit or an open circuit, each switching unit in its actuated state has a resistance R, and the responsive circuit is in its said predetermined stable state only when the series resistance of the groups of switching units is (p.R + Ro), and where Ro is a predetermined fixed resistance of zero or greater.

Claim 3

A system as defined in claim 1, wherein the groups of switching units are connected in series as one arm of a bridge circuit that is balanced only when the series resistance of the groups of switching units is p.R.

Claim 4

A system as defined in claim 1, additionally comprising a warning device responsive to the condition of the responsive circuit and producing a warning signal when, upon sensing an arrangement of first switch selector means and an arrangement of second switch selector means, the series resistance of the groups of switch units is not p.R.

Claim 5

Security control apparatus comprising: a bridge circuit having a variable resistance arm and being in a predetermined condition only when the said arm has a predetermined resistance; p groups of at least two fixed resistors per group each having a predetermined resistance, the fixed resistors in each group being selectably connected in parallel into the associated group and the groups of fixed resistors being connected in series; x switches for each fixed resistor, each switch having a rest state and a selectably actuated state, and any fixed resistor being connected into its group only when all of its associated x switches are in their actuated state; a plurality of first security devices each having a unique predetermined arrangement of m first switch selector means, a plurality of second switch selector means arranged in n groups such that for each said predetermined arrangement of first switch selector means, there is a mating unique predetermined arrangement of n second switch selector means with each of the n second switch selector means being in a different group of second switch selector means; means for conforming the switches to any one of said arrangements of first switch selector means and any one of said arrangements of second switch selector means so that predetermined ones of said switches are actuated by predetermined ones of said switch selector means in a one-to-one correspondence; whereby only for any mating arrangement of first and second switch selector means the total series resistance of the groups of fixed resistors equals said predetermined resistance of the arm; and wherein m, n, p and x are integers, x is greater than 1, and

Claim 6

Security control apparatus comprising: a bridge circuit having a variable resistance arm and being in a predetermined condition only when the said arm has a predetermined resistance; p groups of at least two fixed resistors per group each having a predetermined resistance, the fixed resistors in each group being selectably connected in parallel into the associated group and the groups of fixed resistors being connected in series; x switches for each fixed resistor, each switch having a rest state and a selectably actuated state, and any fixed resistor being connected into its group only when all of its associated x switches are in their actuated state; a plurality of first security devices each having a unique predetermined arrangement of m first switch selector means, a plurality of second switch selector means arranged in n groups such that for each said predetermined arrangement of first switch selector means, there is a mating unique predetermined arrangement of n second switch selector means with each of the n second switch selector means being in a different group of second switch selector means; means for conforming the switches to any one of said arrangements of first switch selector means and any one of said arrangements of second switch selector means so that predetermined ones of said switches are actuated by predetermined ones of said switch selector means in a one-to-one correspondence; whereby only for any mating arrangement of first and second switch selector means the total series resistance of the groups of fixed resistors equals said predetermined resistance of the arm; and wherein m, n, p and x are integers, x is greater than 1, and

Claim 7

Apparatus as defined in claim 4, wherein the bridge circuit is a Wheatstone bridge circuit and the predetermined condition is a balanced condition.

Claim 8

Apparatus as defined in claim 4, wherein the fixed resistors have identical resistance R and the predetermined resistance of the arm is pR.

Claim 9

Apparatus as defined in claim 4, wherein x 2.

Claim 10

Apparatus as defined in claim 4, wherein, only for any mating arrangement of first and second switch selector means, one and only one fixed resistor in each group of fixed resistors is connected into its associated group of fixed resistors.

Claim 11

Apparatus as defined in claim 4, wherein the fixed resistors have identical resistance R and the predetermined resistance of the arm is (pR + Ro), where Ro is the fixed resistance of the variable arm when the bridge is balanced.

Claim 12

Security control apparatus comprising: a Wheatstone bridge circuit with a variable arm, said Wheatstone bridge circuit being so connected as to be balanced only when the resistance of said variable arm has a predetermined value; a plurality of groups of fixed resistors of predetermined resistance associated with said variable arm, the resistors in each said group being adapted for selectable parallel connection between group buses associated with such group, said groups being connected in series in said arm, whereby the resistance of any group is the resistance of those fixed resistors of the group which are connected between the group buses plus any predetermined fixed resistance, and the total resistance of said variable arm will equal the total resistance of all of said groups plus any predetermined fixed resistance; first and second switches associated with each of said fixed resistors, said first switch being adapted to connect a group bus to either end of its associated resistor and being in its rest state connected to that end of its associated resistor electrically nearest the second switch, said second switch being normally open and selectably closable to connect one end of its associated resistor to the other bus of the group whereby, only when said second switch is actuated to be closed, and said first switch is actuated to be connected to the end of its associated resistor electrically remote from said second switch will such resistor be connected between said buses; means for actuating predetermined ones of said first and second switches to correspond to the pattern of switch selector means on any one of a series of first security devices each having a unique one of such patterns, means for actuating predetermined ones of said second switches to correspond to a selected pattern of switch selector means on a second security device; the patterns of first and second switch selector means being arrangeable in mating pairs which correspond to actuated first and second switch positions which connect fixed resistors between the buses of said groups to give said variable arm a total resistance equal to said predetermined value, and wherein non-mating pattern pairs correspond to actuated first and second switch position which give the variable arm a resistance other than said predetermined value.

Claim 13

Security control apparatus comprising: a Wheatstone bridge circuit with a variable arm, said Wheatstone bridge circuit being so connected as to be balanced only when the resistance of said variable arm has a predetermined value; a plurality of groups of fixed resistors of predetermined resistance associated with said variable arm, the resistors in each said group being adapted for selectable parallel connection between group buses associated with such group, said groups being connected in series in said arm, whereby the resistance of any group is the resistance of those fixed resistors of the group which are connected between the group buses plus any predetermined fixed resistance, and the total resistance of said variable arm will equal the total resistance of all of said groups plus any predetermined fixed resistance; first and second switches associated with each of said fixed resistors, said first switch being adapted to connect a group bus to either end of its associated resistor and being in its rest state connected to that end of its associated resistor electrically nearest the second switch, said second switch being normally open and selectably closable to connect one end of its associated resistor to the other bus of the group whereby, only when said second switch is actuated to be closed, and said first switch is actuated to be connected to the end of its associated resistor electrically remote from said second switch will such resistor be connected between said buses; means for actuating predetermined ones of said first and second switches to correspond to the pattern of switch selector means on any one of a series of first security devices each having a unique one of such patterns, means for actuating predetermined ones of said second switches to correspond to a selected pattern of switch selector means on a second security device; the patterns of first and second switch selector means being arrangeable in mating pairs which correspond to actuated first and second switch positions which connect fixed resistors between the buses of said groups to give said variable arm a total resistance equal to said predetermined value, and wherein non-mating pattern pairs correspond to actuated first and second switch position which give the variable arm a resistance other than said predetermined value.

Claim 14

Security control apparatus as defined in claim 10 in which there are from two to 10 groups each containing from two to seven fixed resistors.

Claim 15

Security control apparatus as defined in claim 10, wherein each group contains at least 2 fixed resistors.

Claim 16

Security control apparatus as defined in claim 12, wherein the fixed resistors have the same resistance.

Claim 17

Security control apparatus as defined in claim 10, in which each first security device is in the form of a stiff card which has a unique pattern of embossments as switch selector means and wherein the means for actuating the switches to correspond to said pattern comprises a receptacle for said card; and means within said receptacle operable by said embossments for actuating those switches corresponding to the pattern of embossments on said card.

Claim 18

Security control apparatus as defined in claim 10, in which each first security device is in the form of a stiff card which has a unique pattern of holes as switch selector means and wherein the means for actuating the switches to correspond to said pattern comprises a receptacle for said card; and means within said receptacle operable by said holes for actuating those switches corresponding to the pattern of holes on said card.

Claim 19

Security control apparatus As defined in claim 15 comprising latch means for retaining said card in said receptacle, latch actuating means within said receptacle operable by said card as the same is pushed home in said receptacle to retain said card therein; and latch release means for releasing said card for withdrawal from said receptacle.

Claim 20

Security control apparatus as defined in claim 16, wherein said latch release means is actuated only in response to the balancing of the Wheatstone bridge.

Claim 21

A security control device as defined in claim 13, wherein each first security device is a key having a unique pattern of slots as switch selector means and wherein said means for actuating said switches comprises a lock mechanism in which there is a rotatable disc for each slot of said key, each such disc being rotatable through a predetermined angle corresponding to the depth of the slot to which it corresponds, and a detent on the periphery thereof adapted to cooperate with a plurality of third switches angularly positioned within said casing in angular positions corresponding to the predetermined angles through which said disc may be rotated, whereby upon rotation of said key through one full revolution said detent will cooperate with one of said third switches to actuate the same, each of said third switches associated with each of said discs being connected to control the position of a corresponding one of the first and second switches whereby upon a key being turned through one complete revolution the first and second switches corresponding to the slots of the key are actuated.

Claim 22

A security control device as defined in claim 13 in which each first security device has a unique pattern of switch selector means in the form of eyelets of varying predetermined depth adapted on insertion in a receptacle associated with the bridge circuit to cooperate with plunger elements of plunger-type selector switches, the contacts of said plunger-type selector switches being adapted to actuate corresponding ones of the first and second switches.

Claim 23

Apparatus as defined in claim 13, additionally including means responsive to the balancing of the bridge circuit to initiate the operation of a controlled machine.

Claim 24

Apparatus as defined in claim 20, additionally including a warning device responsive to the bridge circuit and providing a warning signal when non-mating pairs of patterns of first and second switch selector means actuate the switches thereby to cause an imbalance of the bridge circuit.

Claim 25

Apparatus as defined in claim 13, wherein the second switch selector means are physically associated with a series of second security devices each of which has a unique predetermined pattern of second switch selector means mating with a unique predetermined pattern of first switch selector means on a predetermined one of said first security devices.

Claim 26

Apparatus as defined in claim 13, wherein the second switch selector means are arranged in groups and are physically associated with a manually operable device having individually-adjustable means for each said last-mentioned group for selecting in each group any one of the second switch selector means in such group whereby the selected second switch selector means actuate corresponding ones of said first and second switches, and wherein each pattern of first switch selector means mates uniquely with a unique selection of second switch selector means taken one from each group of second switch selector means.