US 3896345 A
Description (OCR text may contain errors)
United States Patent 1191 Zink [111 7 3,896,345 July 22, 1975 PHOTO LOCK SYSTEM  Filed: Sept. 3, 1974 Tinsley 21 A l.-N0.Z 502 851 1 pp 57 ABSTRACT An access control system for actuating a latch or other [if] 3l7/ligks2B5g/75/gz) device when the pp p y member is inserted. A receptacle with photocens at first and Second  Field of Search 317/134; 250/555, 556,
trons w1th a transparency at the first station. A film strip key member with a complementary transparency and an average transmission or gray scale on the re-  References Cited mainder of the film matching that of the complemen- UNITED STATES PATENTS tary transparency. Detector circuitry having the pho- 3,5l4,611 5/1970 Cohen 250/557 tocells connected in the input for actuating a latch or Baskerville et a1. an alarm as a function of the particular key 3,787,714 1/1974 Resnick et al. 317/134 member inserted 3,793,565 2/1974 Smith 317/134 3,835,297 9/1974 lnoue et al.... 250/557 9 Claims, 3 Drawing Figures T0 Access tpfy 5,351,759
3,845,362 10/1974 Roe 317/134 Primary Examiner-.L. T. Hix
Attorney, Agent, or Firm-Harris, Kern, Wallen &
' II7 MA.C.
PATENTED JUL 2 2 ms 70 A C6555 CONTROL DE V/ CE MECHANICAL LA g EAL. ADJ.
L A MP 5UPPL Y PHOTO LOCK SYSTEM This invention relates to access control of an electrooptical nature intended as a replacement for the conventional mechanical and magnetic types of locks and access control systems presently in use.
Some optical access systems have been proposed, including those shown in US. Pat. Nos. 3,773,862; 3,619,060 3,769,514; 3,818,190; 3,797,936; 3,584,958; 3,457,013; 3,124,636; 1,135,919; and 1,775,794, but none of these prior art devices have the structure or the advantages of the system as disclosed and claimed herein.
The new system provides an optical or photographic coding which can have unlimited variations and which can be highly personalized. In one embodiment, a transparency such as a photographic negative is installed in the receptacle and a complementary transparency such as a positive of the same photograph is utilized in the key number, with access being obtainable only when the complementary transparencies are positioned adjacent to each other.
The present system also providesa two-step configuration which not only gives increased protection against unauthorized entry, but which also can provide an alarm or other indication whenentry is attempted utilizing an improper key member.
The preferred embodiment incorporates a receptacle with photocells or other radiation sensors at first and second stations, with a transparency at the first station. Positioning the complementary transparency at the first station will normally provide an access signal for actuating a latch or other control device. However, the
complementary transparency of the key member as well as other portions of the key member must pass the second photocell and if the average transmission of the complementary transparency and the average transmission of the other portions of the key member do not match a predetermined value, generation of the access signal will be blocked. While reference is made herein to generation of an access signal and operation of a latch, it will bereadily understood that the system of the invention can be utilized for other purposes and that basically it serves to indicate whether or not the key member being inserted is properly coded for the particular receptacle. I
Accordingly. it is an object of the invention to provide a new and improved control system of the type described above. It is a specific object of the invention to provide such a control system incorporating two detection stations, and utilizing complementary transparencies for identification. Other objects, advantages, features and results will more fully appear in the course of the following description. The drawing merely shows and the description merely describes a preferred embodiment of the present invention which is.given by way of illustration or example.
In the drawing:
FIG. 1 illustrates an access control system incorporating the presently preferred embodiment of the invention;
FIG. 2 is a perspective view illustrating the relationship of the receptacleand key member; and
FIG. 3'is' an exploded view illustrating the construction of the receptacle of FIG. 1.
- The system illustrated in FIG. 1 includes a receptacle 10, a key member 11, a control circuit 12, and a latch 13.
A typical receptacle construction is shown in greater detail in FIG. 3 and includes plates l8, 19 carried in spaced relation by sides 20, 21 defining a slot 22 between the plates for receiving the key member 11. A stop 23 is mounted between the plates at one end thereof. The receptacle components typically are made from plastic sheet stock, cut to size and cemented together.
Openings 26, 27 are provided in the plate 19 for receiving photocells 28, 29 resepectively, which function as radiation sensors. Similar openings (not shown) are provided in the plate 18 for receiving lamps 30, 31 which serve as radiation sources. As shown in FIG. I,
lamp 30 directs radiation across the slot 22 to the sensor 28 and lamp 31 directs radiation across the slot to sensor 29. The lamps are connected to a power source via leads 32. Of course, other radiation sources and sensors can be utilized as desired and in one alternative configuration, a single lamp can serve as a radiation source for both sensors.
The system includes complementary transparencies, typically a negative and a positive of a photograph. One of the transparencies, the negative 35 in the embodiment illustrated, is mounted in the receptacle at one of the openings for the photocell 28 and lamp 30. The other transparency, in this embodiment a positive 36, is carried by the key number 11. In the preferred embodiment illustrated, the key member is a strip of 16 mm film with the positive printed directly on the film. The image of the positive is positioned on the key member so as to be exactly superimposed over the image of the negative 35 when the key member is fully inserte into the receptacle.
The remainder of the key member, or at least those portions which move past the opening 27 as the key member is inserted, has an average radiation transmission characteristic substantially the same as that of the positive 36. This is readily accomplished by providing an overall gray shade for the remainder of the film strip equal to the average density of the positive. The film strip forming the key member may be protected by laminating between plastic cover sheets.
In the control circuit 12, the photocell 28 is connected in series with a variable resistor 40 across a voltage source at terminals 41, with the junction of the photocell and resistor connected as an input to an integrated circuit 42, typically a Signetics NE 555 2 or a Motorola MC 1555. The circuit 42 provides an access signal on output line 43 indicating that a proper key member has been inserted into the receptacle. The access signal may be utilized for any purpose including actuation of an access control device, an indicator, a recording device or the like. In the embodiment illustrated, the access signal is utilized to actuate the latch '13 by energizing a solenoid 45 through a transistor amplifier 46, with the solenoid functioning to remove a bolt 47 from a jamb 48.
nected to an alarm or indicator or recorder orthe like to indicate that an attempt has been made tofoperate the system by an improperly coded key member.
The system is initially adjusted by inserting the properly coded key member part way into the receptacle, with the key member at the sensor 29 but not at the sensor 28. The resistor 51 is varied to provide a zero voltage at input terminal 2 of the integrated circuit 52, with no blocking signal on the output line 53. Resistor 40 is adjusted to provide a voltage at input terminal 2 of integrated circuit 42 such that there is no access signal on the output line 43 except when there is no radiation at sensor 28. The system is now ready for use.
A person seeking access inserts a key member into the slot of the receptacle. As the key member passes the sensor 29, the resistance of the photocell increases and the voltage at terminal 2 of circuit 52 decreases. If the gray scale or average transmission characteristic of the inserted key member is proper, the voltage at terminal 2 will be zero. When the key member is fully inserted, the transparency 36 will be in line with'the transparency 35 providing a complete blocking of light transmission to the sensor 28..The resistance of the sensor 28 goes up and the voltage at terminal 2 of integrated circuit 42 goes down sufficiently to provide an output at line 43, which for the specific circuits illustrated is about +9 volts. This is the access signal, indicating that a properly coded key member has been inserted into the receptacle.
However, if the gray scale or average transmission of the key member is less than that for the properly coded key member, less light will arrive at the photocell 29 resulting in a darker field, with a higher resistance for the photocell and a lower or negative voltage at terminal 2 of integrated circuit 52, which produces an output on line 53. This output is the blocking signal and typically is about +9 volts. The blocking signal can be utilized to actuate an alarm. Also, the connection of the blocking signal to terminal 1 of integrated circuit 42 serves to block or prevent operation of the circuit to provide an output at line 43, regardless of the signal at input 42. u
If the transmission characteristic of the key member is greater than that of the properly coded key member, more radiation arrives at the sensor 29, the photocell resistance goes down and the, voltage at terminal 2 of integrated circuit 52 goes up or positive. This does not affect integrated circuit 52, however placing the positive voltage at input terminal 4 of integrated circuit 42 blocks or prevents operation of the circuit 42 so that there is no access signal on output line 43 regardless of the. signal at input terminal 42.
Even if the average transmission characteristic of the key member matches that of a properly coded key member, access cannot be obtained if the transparency of the keymember is not a complement of the transparency of the receptacle. When the transparencies are not complements, there will be some light transmission to the photocell 28 and the voltage at terminal'2of integrated circuit 42 will not go sufficiently negative to trigger an output. Hence it is seen that access cannot be obtained by inserting a completely opaque key member. This type of key member would provide the proper signal at terminal 2 of circuit 42, but the circuit 42 would be blocked by the output-from the sensor 29 in the manner described above.
A time delay may be used with the units 42 and 52 so that once the circuit has been triggered to provide an output, this output will be maintained for a preset length of time. Typically the time is several minutes and permits the person with the properly coded key member to remove the key member and perform other acts such as opening a door, entering a building and deactivating an alarm system within the permitted time interval. The time delay may be obtained by means of a typical RC circuit, as by connecting a resistor 55 between terminals 8 and 6, 7, and a capacitor 56 between terminal 6, 7 and circuit ground of unit 42. A similarRC circuit may be used for the unit 52.
Although an exemplary embodiment of the invention has been disclosed and discussed, it will be understood that other applications of the invention are possible and that the embodiment disclosed may be subjected to various changes, modifications, and substitutions without necessarily departing from the spirit of the invention.
1. In an access control system, the combination of:
a receptacle having a first station and a second station and including means defining a slot for receiving a key member for movement past said first station to said. second station;
a first radiation sensor mounted at said first station;
a second radiation sensor mounted at said second station;
means for directing radiation across said slot to each of said sensors;
a first transparency mounted at said first station; and
a key member having a second transparency which is the complement of said first transparency, with said second transparency positioned on said key member to move past said second station to said .first station as said key member is inserted into said slot, and with at least the portions of said key member which are at said second station during insertion having an average radiation transmission characteristic substantially the same as that of said second transparency.
2. A system as defined in claim 1 wherein said transparencies are a photographic positive and a photographic negative.
3. A system as defined in claim 2 wherein said key member is a strip of photographic film with said second transparency a part thereof.
4. A system as defined in claim 1 wherein said receptacle includes spaced plates providing said slot therebetwe'en, each of said plates having an opening at said first stationand at saidsecond station for receiving said sensors and a radiation source.
'5. A system as defined in claim 1 including:
a first detector having an input and an output; and
first circuit means connecting said first sensor to said first detector input, with said first detector providing an access signal at the output thereof when a complementary second transparency is opposite said first transparency blocking substantially all radiation to said first sensor.
6. A system as defined in claim 5 including:
a second detector having an input and an output,
second circuit means connecting said second sensor to said second detector input, with saidsecond detector providing a blocking signal at the output thereof when a key member having an average radiation transmission characteristic substantially different from that of said first transparency is positioned at said second station; and
third circuit means connecting said blocking signal to said first detector for blocking any access signal output.
7. A system as defined in claim 6 with said second circuit means also connecting said second sensor to said first detector, with said second detector providing said blocking signal when said key member average transmission is less than that of said first transparency. and with the signal from said second sensor providing a tion of said device by an access signal.
P ATENT NO. 1 3,896,345 I I DATED ul zz, 1975 UNITEDISTATES PATENT ANDITRADEMARK OFFICE 1 I CERTIFICATE CORRECTION INVVENTOR(S)YI Henry R. Zink It is certifiedihafrror appears in th'abov-identified patntahd that s aid L etters Pat ent are hereby corrected as shown blow:
"'[SEALI  InventorsaddreS, Z:i.p179 2352 should be 934S2--- 7 Column ,1 line-8 "3,773,862" should be '--s, 733,862-- Column 1, line 21 "n umbef should be -'-member-- also.
Column 2, line 30. V I I r I I I Bignc d and Blcld this I fourze er ith Day of '0 ctobe r 1975 A ttest:
RUTH C. MASON I I C. MARSHALL DAN'N Arresting Officer Commissioner uflarents and Tr ailema rks UNITED STATES PATENT AND TRADEMARK OFFICE CETIFICATE OF CORRECTION PATENT NO. 3,896,345 DATED July 22, 1975 lN\/ ENTOR(S) Henry R. Zink It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
 Inventor's address, Zip "92352" should be "93452-- Column 1, line 8 "3,773,862" should be --3,733,862-- Column 1., line 21 "number" should be --member-- also Column 2, line 30.
Signed and Sealed this fourteenth Day of Oct0ber1975 [SEAL] A tteSt.
RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Parents and Trademarks