GB2364546A - Security lock with code entry device - Google Patents

Abstract

A lock 13, 14, 15 for a closure member 11 comprises a memory (27, fig.4) for storing a release code, and code entry means 17, 19, 20, 21 for generating a lock release request, in which the code entry means comprise at least one user - operable element cycling means 19, 20, 24 operable to cycle through the available code elements, code elements selector means 21 for indicating selection of a code element, and release request signaling means 22 for signaling a release request on the basis of a code assembled by successive operation of the code element cycling means 19, 20, 24 and the code element selector means 21, 26. A single key or like selector member may be operated to select a plurality of code elements to assemble a code for comparison with the stored code in the lock.

Description

2364546 AN IMPROVED SECURITY LOCK The present invention relates to an

improved security lock, and particularly to an electronic lock which can be operated in a manner which corresponds in many 5 respects to the operation of a mechanical security lock.

Where it is required to provide closure members with highly secure locking means, for example for cash drawers, safes, building doors, windows or the like, it is known to make use of a mechanical rotary lock (the so-called combination lock) having a dial 10 with numbers marked on its periphery, typically from 0 to 100, which is operated by turning the dial first in one direction and then in another to bring certain numbers into register with an index mark on the lock casing. In fact, rotation of the dial causes corresponding rotation of a number of internal gates or tumblers which are left each in an angular position corresponding to that at which the direction of rotation of the 15 dial is successively changed. In this way the gates can be brought into a specific alignment to allow release of a lock bolt which secures the closure member. Such locks have been in use for many years with a high degree of success, but with the increasing sophistication and sensitivity of electronic detection equipment it is now becoming possible for illicit operation of such locks to be enabled by using electronic 20 monitoring equipment which acts to detect small sounds emitted by the lock when the appropriate parts come in to register, or alternatively, to detect other physical phenomena such as magnetic or electromagnetic changes in the lock caused by such alignment. Unauthorised opening of otherwise secure closures is, therefore, much more likely than in the past. This has resulted in a search for alternative locking 2 mechanisms which provide a high degree of security without utilising mechanical components, but the operation of which cannot be detected from outside the lock to enable unauthorised use of the lock mechanism, and in particular to seek electronic means for achieving the same or a similar result.

Of course, electronically controlled electrical lock mechanisms are known, these usually being provided with a keypad by which a user can enter a security code which causes release of the lock in a manner comparable to the operation of a key.

Conventionally such keypads have a decimal numeral system with one or two 10 additional keys with special functions and identified by additional characters such as #, and the like. Such keypads have a weakness in that methods exist to detect the pattern of keys depressed by obtaining a trace of the grease deposited on the keys by a user's finger. Although this could be overcome by wearing gloves, such measures are not acceptable for environments where people may be required to come and go 15 through a secured door, or where people may require random or casual access to the secured envirom-nent. Moreover, even this could be circumvented by "dusting" the keys with powders traces of which are transferred from one key to the other as a sequence of numbers is entered by depressing successive keys.

20 This possibility of corruption of secure locks has led to a further investigation of means for maintaining security. One system which has been tried has a plurality of keys which are illuminated in such a way that the numbers represented thereby can be changed. Thus, by contrast with a normal numerical keypad in which the keys have a single uniquely allocated numeral, the keys of this prior art keypad may have a different signification, that is a different allocated numeral, on different occasions. For example, where the top row of a keypad normally may show the numerals 1, 2, 3, the numbers shown may be scrambled so that, for a given operation, the top row shows numbers 5, 8 and 4 and on a subsequent occasion 6, 4, and 7. Tben, if the keys 5 have been "dusted" the significance of the order in which the keys were depressed is of no relevance to the order in which the keys must be next pressed in order to enter the same code. Such locks are heavy, bulky and expensive however, and run the risk that should the scrambling mechanism fail in any way the sequence of key depressions required to open the lock cannot be determined.

The present invention seeks to provide a lightweight, simple and secure alternative to this prior art lock which, however, will not suffer from the risk of corruption by "dusting" and which will nevertheless provide an easy and familiar means for entering combinations of numerals to represent a release code.

is According to one aspect of the present invention, therefore, a lock for a closure member, of the type having a memory storing a release code, and code entry means generating a lock release request, is provided with code entry means comprising at least one user-operable code element cycling device operable to cycle through the 20 available code elements, code element selector means for indicating a user's selection of a code element, and release request signalling means for signalling a release request on the basis of a code assembled by successive operations of the code element cycling device and the code element selector means.

According to another aspect the present invention provides a lock for a closure member, of the type having a memory storing a release code, and code entry means for generating a lock release request which causes or enables release of the lock if the code entered matches the stored code, in which a single key or like selector member 5 is operable to select a plurality of code elements to assemble a code for comparison with the stored code in the lock.

The code entry means may include a keypad carried by the closure member or by a part of the structure defining the opening to be closed by the closure member. The 10 keypad may have first and second code element cycling keys depression of which acts to cause the code element cycling device to cycle through the code elements in one direction or the other respectively. Thus, in the case of a lock in which the code elements comprise a predetermined or selectable set of numeric or alphanumeric characters, one code element cycling key may cause the numerals or characters to 15 cycle through an ascending order whilst the other causes cycling in descending order.

In one embodiment of the invention the code entry means may include a keypad releasably connectable to the lock for transmission of code signals thereto rather than being permanently connected as in the case of other embodiments.

As a further alternative the code entry means may include remote signal transmission means for transmitting code signals to the lock from a location remote therefrom. The code entry means may comprise a keyboard or keypad, and such keypad may have a plurality of keys only some of which are enabled for operation. For example, the keypad may comprise a conventional decimal keypad some keys of which have no function. Alternatively, the keys of the keyboard or keypad be grouped so that several different keys provide the same function, or the keypad may have a membrane overlay identifying the enabled keys and blanking off the keys which have no 5 function. Alternatively, of course, a specially-designed keypad may be provided with appropriate keys for the code element cycling and code element selector functions, and any other special function to be performed on or by the lock.

The code entry means requires the presence of a display for displaying the code 10 elements in a form which enables identification of the selected code elements. This may be achieved, for example, by displaying only a code element or those code elements which are available for selection at any one time, this display being changed upon each operation of a code element cycling key. Upon operation of the code element selector the display may remain unchanged or may revert to a standard 15 representation. In the latter case the program may require the code element cycling to take place in a different direction after each successive selected code element is entered for assembly.

The display may also act to display all the selected and entered code elements until 20 such time as the lock release request signal is generated, in which case the positions occupied by successive code elements may be identified as "active", either by illumination or by flashing, or by positional location.

One conventional combination lock can be set by reference to successive pairs of 6 digits of a six digit code by turning the dial to successive two-digit positions (the digits 0 - 9 being represented 00, 01, 09) and an embodiment of the present invention may be formed to simulate this type of operation by arranging for the display to be constituted by pairs of numerical digits selected by operation of the code 5 element cycling device. Thus, for example, the code 20-30-40 may be selected by depressing one of the code element cycling keys until the digits 20 appear in the display, depressing the "select" key to indicate selection of these digits, further cycling of the code element cycling device by depression of the same or the opposite key (depending on which embodiment is under consideration) until the digits "30" 10 appear, depressing the code selector key and then repeating the operation for the digits 6640".

As mentioned above, the cycling of the code elements may require successive alternate operations of the code element selector device so that a first code element 15 or pair of code elements is selected by cycling through the code elements in ascending order, the second code element or pair of code elements is selected by cycling through the code elements in descending order (returning to the highest when the lowest has been reached) and subsequently cycling in ascending order to select the final digit or two digits.

Of course, embodiments of the invention may be provided in which it is only possible to cycle in one direction, in which case only one push button key is required rather than two push buttons for cycling in each of two opposite directions.

The present invention may also be embodied in a lock provided with means for changing the lock release code enabled by entry of the current lock release code and operable to enable selection of a new lock release code by operation of the said code element cycling means.

One advantage of such electronic locks resides in the fact that the memory may have a number of address locations for a plurality of different lock release codes each of which is valid, but may be known to only one or a limited number of users. Because electronic locks can also be provided with means for recording the sequence of 10 operations to which it is subject (the so-called audit trail) a lock in which each of a limited number of users has their own unique code enables the record to identify the order in which each individual accesses the secure environment. Such an audit trail may be very detailed: for example, it is possible to monitor not only the status of the closure member itself (e.g. door open/closed) as well as other parameters such as the 15 temperature within the secure environment at each opening. Of course, with the provision of a timing circuit it is also possible to determine exactly when each individual accessed the secure environment as well as determining the order in which such access was gained. Should any one individual consider that the security of his secret code be compromised it is a simple matter then for him or her to change his or 20 her own unique code using the keys available on the face of the lock without reference to any higher authority or revealing its change to any other member of the group.

This enables a much higher level of security to be obtained, in fact, than if only a single security code is available to the lock.

Because, typically, the lock may have a hundred or more numerals through which to cycle, the known arrangement by which a single keystroke causes the code elements to increment by one unit and a continuous depression (after a timed delay) causes high speed cycling of the code elements to take place for as long as the key is depressed, 5 may be adopted. The rate of cycling may be constant or may increase with time if the key is maintained depressed beyond the initial limit.

Various embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in 10 which:

Figure I is a schematic view of a closure in the form of a door fitted with a lock formed as an embodiment of the present invention; Figure 2 is a front view of the keypad face of the embodiment of Figure 1;

Figure 3 is a schematic view of an alternative embodiment of the invention; 15 and Figure 4 is a block diagram illustrating the major components of which the invention is composed.

Referring first to Figure I there is shown a door generally indicated I I which may be 20 a security door such as the door of a safe or an access door in a building. The door closes within a frame 12 and is fitted with a lock generally indicated 13 for selectively operating a bolt 14 receivable in a keeper 15 on the frame 12.

Operation of the lock 13 is achieved by actuating the keys of a keypad 15 to enter a release code which, when entered correctly, may either automatically cause release of the bolt 14 (for example by way of a solenoid) or may disengage bolt-locking means to allow the bolt 14 to be withdrawn by operation of a ftu-ther element such as the door knob 16 illustrated in Figure 1.

In the embodiment of Figure I all of the control electronics are housed in the casing 13 on the "secure" side of the door, the front casing 15 housing only the keys and a display screen 7 connected to the secure lock by appropriate cables. A housing 18 for a battery may also be provided in the front casing 15 although in alternative embodiments this may be provided on the secure side of the door I I in the casing 13.

Referring now to Figure 2, the code entry to the lock is achieved with the use of only a limited number of keys comprising two code element cycling keys 19, 20 a code element selector key 21, a "lock release" key 22 and a further key 23 usable for changing the codes stored within the lock by means of a routine which will be described in more detail below. As with the battery housing, the "change code" key may be positioned instead on the secure side of the door 11.

The lock itself may be of a type described in the applicants own European Patent EP 0 469 932 D1 the details of which are incorporated herein by reference. The present invention differs from that earlier lock in that the code entry is effected by means of the two cycling keys 19, 20 one of which, the key 19, acts to cycle the available code elements in decreasing order of magnitude whilst the key 20 acts to cycle the code elements through an ascending order of magnitude. The display screen 17 displays two digits in the central location. Depression of the key 20 causes the numeral displayed to increase whilst depression of the key 19 causes it to decrease. By operating on these two keys the user selects a first pair of numerals and, when satisfied with the choice, to press his key 21 which enters these numerals into a short 5 term memory for comparison purposes as will be described in more detail below.

Having depressed the key 21 the keys 19, 20 can then be operated again to select a different pair of numerals for the next selection (always assuming, of course, that the code required by the memory comprises different numerals); it is possible for a code to be constituted by a pair of numerals repeated once, or even twice, if desired there 10 being no limit on the choice of successive numerals based on the previous selection.

This operation is then performed a third time for a third pair of digits to be assembled and then selected by depression of the key 2 1. When the three pairs of digits have been selected, and assuming the operator is satisfied with the selection as representing 15 the code known to him or her as the release code of the lock, key 22 is depressed to send a lock-release signal to the lock-operating mechanism or the bolt-release mechanism as appropriate, and this is compared with the stored code in the lock to establish whether a valid lock release request has been made. If this is the case a solenoid is energised to cause or enable release of the bolt 14 and the closure door 11 20 can be opened. Of course the starting display need not always be the same but could be a random number. Also the display could show a different number of digits, in particular one or three. And the cycling key need not necessarily cycle from the lowest significant number displayed, but could cycle at a higher level.

Figure 4 illustrates a simple block diagram representing the main components of the lock of this invention. These components comprise the front casing or keypad 15 having a variety of keys which have been identified with the same reference numerals as the keys of Figure 2 for the same purpose, namely two keys 19, 20 for cycling the 5 code elements, a code element selector key 21, a lock release request key 22 and a code change key 23. The code element cycling keys 19, 20 are connected to the set and reset inputs of a shift register 24 the output of which on a bus 25 is applied to a central processor unit 26 connected for bi-directional transmission of data with a memory 27 in which the release code is stored. The central processor unit has an 10 output line 28 connected to a relay 29 connected between a positive voltage supply source 30 and a solenoid 31 which operates to shift the bolt 14 or, in the embodiment not illustrated, the bolt-release member (not show).

The central processor unit 26 is also connected to the code entry or selector key 21 1-5 and to the code change key 23, whilst the lock release request key 22 is connected via an interface unit 32 to the input of a comparator 33 the output of which is applied to the relay 29. The comparator 33 may be a simple AND gate which triggers energisation of the relay 29 if the output from the CPU is a signal at the appropriate logic level (high or low depending on the logic strategy employed) which is output 20 from the CPU when the input signal from the shift register 24 on the bus 25 matches the access code stored in the memory 27.

In the alternative embodiment illustrated in Figure 3 a conventional keypad 34 having 10 keys 35 identifying the numerals 0 - 9, and two keys marked # and, with a display panel 36, is connected to the shift register 24 in place of the special purpose keyboard illustrated in Figure 2. In this embodiment only the keys # and, 2, 4, 6 and 8 are enabled, keys 7, 9, 5, 1 and 3 perform no function. Keys 4 and 6 act as the code element cycling keys, key 8 acts as the code entry key, key acts as the lock release 5 request key and key # as the code change key. This embodiment may be provided with or without an overlay such as that illustrated in Figure 3 for blanking off those keys which do not fulfil a function in the lock.

In other embodiments, not shown, there may be provided a specific key for generating 10 an audit trail output (this having been stored in a lock over the passage of time) which may be read from the screen (in coded format) or output on a line (not shown) to a terminal or to a remote station. Indeed the audit signals may be transmitted at this time for a remote station at each opening or closure of the door, to allow remote monitoring of its status. The lay may have a so-called "timeout" function in that the is effect of any keystroke will be cancelled after a predetermined short period of time, e.g. ten or twenty seconds. This prevents corrupt authorised user from entering the release code and then effectively leaving the door "unlocked" by deferring the last "entry" keystroke for a later time, such as after working hours or when an accomplice has arrived. It is important to realise also that the lock does not store the last number 20 entered but merely compares it with a permanently stored code in the secure environment.

13

Claims (20)

1. A lock for a closure member, of the type having a memory storing a release code, and code entry means for generating a lock release request, in which the code 5 entry means comprise at least one user-operable element cycling means operable to cycles through the available code elements, code element selector means for indicating selection of a code element, and release request signalling means for signalling a release request on the basis of a code assembled by successive operating of the code element cycling means and the code element selector means.

2. A lock for a closure member, of the type having a memory storing a release code, and code entry means for generating a lock release request which causes or enables, release of the lock if it matches the stored code, in which a single key or like selector member is operative to select a plurality of code elements to assemble a code for comparison with the stored code in the lock.

3. A lock as claimed in Claim I or Claim 2, in which the code entry means include a keypad carried by the closure member or a part of the structure defining the opening closed by the closure member.

4. A lock as claimed in Claim 3, in which the keypad has first and second code element cycling keys depression of which acts to cause the code element cycling means to cycle through the code elements in one direction or the other respectively.

5. A lock as claimed in any preceding claim, in which the code elements comprise a predetermined or selectable set of numerical or alphanumeric characters.

6. A lock as claimed in Claim I or Claim 2, a Claim 4 or 5 when dependent 5 thereon, in which the code entry means include a keypad releasably connectable to the lock for transmission of code signals thereto.

7. A lock as claimed in Claim I or Claim 2, or Claim 4 or 5, in which the code entry means include remote signal transmission means for transmitting code signals to the lock from a location remote therefrom.

8. A lock as claimed in any preceding Claim, in which the code entry means comprise a keyboard having a plurality of keys only some of which are enabled for operation,

9. A lock as claimed in Claim 8, in which the keyboard has a membrane overlay identifying the enabled keys.

10. A lock as claimed in Claim 8, in which the selection of enabled keys is 20 variable by operation of a selector key or keys on the keyboard.

11. A lock as claimed in any preceding claim, further including a display for displaying the selected code elements.

12. A lock as claimed in Claim 11, in which only a code element or the code elements being selected at any one time are displayed, the display reverting to a standard representation each time a selected code element is entered for assembly.

5

13. A lock as claimed in Claim 11, in which the display acts to display all the selected and entered code elements until such time as the lock release request signal is generated.

14. A lock as claimed in any of Claims 11 to 13, in which the display acts to 10 display pairs of numerical digits selected by operation of the code- element cycling means.

15. A lock as claimed in any preceding Claim, in which there are provided means for changing the lock release code enabled by entry of the current lock release code is and operable to enable selection of a new lock release code by operation of the said code element cycling means.

16. A lock as claimed in any preceding Claim, in which the code element cycling means acts to cycle through the available code elements in opposite directions 20 alternatively between successive operations of the said code element selector means.

17. A lock as claimed in Claim 16, in which the code element cycling means include two push button keys operable to cycle through the available code elements in respective opposite directions.

18. A lock as claimed in Claim 17, in which each push button key acts to advance the code elements incrementally by one unit upon each depression thereof and to advance the code elements at a given rate if the key is maintained depressed for a time period greater than a given theshold.

19. A lock as claimed in Claim 18, in which the said given rate increases with time if the key is maintained depressed for a further time period.

lo

20. A lock as claimed in any preceding Claim in which the code elements comprise a hexadecimal set of alphanumeric characters.