Background of the Invention

This invention relates to a lock, operable in response to each of a plurality of access keys, detecting which of the access keys is used in opening the lock.

The ability to keep a record of access to locked articles is desirable in many businesses. For example, in many instances it is important to keep certain items or areas restricted to only those persons possessing an access key. It is also desirable to keep track of which individuals have gained access, especially when a large number of like keys are in simultaneous use.

This problem has been addressed through the use of electronic keypads, card readers, and other dual devices wherein a key and some other identifying device or process is required. A user might be required to insert a magnetic card or press in a keypad identification number, before using his key.

All electronic identification locks possess disadvantages in that such locks fail to operate when power is not present, and identification codes may be observed by unauthorized persons as the code is being entered.

The prior art includes a lock actuated by keys which are provided with light actuated means indicating

authorization or lack thereof. Such locks are illustrated in United States Patent Nos. 3,733,862 and 4,996,514. Others have introduced mechanical locks, with position switches attached, the disadvantage being that only a few electronic identification means may be provided.

Devices constructed in accordance with the invention overcome these and other disadvantages by providing encoded keyed alike keys with a lock capable of identifying which of these keys is operating the lock. Accordingly, it is an important object of this invention to provide a lock which will operate for any person having possession of one of many keys fitting a particular lock pattern as selected for the lock. Each key has a different identification code made possible by an arrangement of notches on the key. Thus, the assigned possessor of the key.may be identified when the key is used in the lock.

Another important object of the invention resides in the fact that even in the event of complete loss of power, the lock will still operate, although it will be unable to identify the assigned possessor of the key.

Summary of the Invention

A key configured in both a conventional manner to operate a mechanical lock and in a predetermined pattern of notches and the like when inserted into the lock and turned, either blocks or allows light beams to pass to light detection circuitry capable of reading the pattern of the notches to identify the particular key being used in the lock. The detected pattern of blocked or non-blocked light beams is decoded into a key identification number or symbol. Thus, the method contemplates providing keyed alike keys for operating a lock, and encoding said keys with a pattern of notches indicating which of the keyed alike keys is used in operating the lock.

Brief Description of the Drawings

The construction designed to carry out the invention will be hereinafter described, together with other features thereof. The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown and wherein:

Figure 1 is a perspective view illustrating a storage box containing a stored key having a lock and key access constructed in accordance with the invention mounted on the window of an automobile;

Figure 2 is a longitudinal sectional elevation taken on the line 2-2 in Figure 1; Figure 3 is a perspective view illustrating a lock and access key arrangement mounted as in Figures 1 and 2 together with sensor mechanism for determining the identity of the access key;

Figure 4 is a transverse sectional elevation taken on the line 4-4 in Figure 3;

Figure 4-A is a transverse sectional elevation similar to Figure 4 but illustrating the lock with the access key in unlocked position;

Figure 5 is a schematic perspective view illustrating

the access key and related parts of the lock; and

Figure 5-A is a schematic side elevation illustrating mechanism for actuating detection circuitry.

Description of a Preferred Embodiment

The drawings illustrate a lock having a cylinder housing, and a cylindrical plug for receiving an access key in an elongated axial slot. The lock is shown positioned for securing a drawer of storage box A in closed position. A plurality of spaced apertures in the plug permit the passage of light therethrough. Light passage means in the cylinder housing permit the passage of light to the spaced apertures in the plug. A plurality of encoded access keys B each have at least one notch arranged therein to permit the passage of light through a predetermined opening in the plug. The key excludes the passage of light through another predetermined opening in the plug. The notches are arranged to encode information indicating which person or persons selected from a larger group of authorized persons is identified with each key. A light sensor receives the information encoded in the predetermined arrangement of notches when a key is inserted into the slot in the plug for actuating the lock. Figures 1 and 2 illustrate a storage box A positioned upon the glass 10 of the window of an automobile 11 by suspending it upon a clip 10a. The box A is illustrated as including an abutment 12 which projects inwardly to provide a stop for locking a cam 13 carried by the cylindrical plug

14 of the lock against forward movement which would permit opening of a drawer 15. The lock is carried in the slidable drawer 15 within the lock box A for storing a desired article such as an operating key 15a for the respective automobile upon which the box is carried. If desired, another suitable access means or closure such as a hinged door and the like may be utilized for blocking access to a storage device.

An access key B is illustrated in Figure 5 as having a shank with a guiding groove 16. The access key is notched or provided with serrations including projections 17 along one edge in a conventional manner. Such an access key cooperates in a tumbler type lock so that the notches and intervening projections 17 operate the usual tumblers permitting rotation of the plug 14. The spine 18 of the shank of the key is .illustrated as being notched as at 19 in a pattern to cooperate with suitable multiple bores or other aperture means 20 in the lock body or housing 21.

When an inserted key has serrations correctly matching suitable tumblers, the plug may be rotated about its axis. A cam 13 or other locking arm or device, is attached to the plug, causing locking and unlocking or some other desired function when the plug is rotated. The body or housing 21 retains the plug and houses suitable tumblers (not shown) and their associated parts.

A series of passages or apertures 20 is formed in the body 21 of the lock and a series of openings 22 are placed in the plug so that when the plug is rotated in the body to an actuating position, the light passages in the plug and the light passages in the body line up so that in the absence of any intervening or masking key material, light may pass through the light passages or other suitable openings in the body of the lock, through the spaced light passages or apertures in the plug, and on out through to the other side of the lock.

The notches are illustrated as being in the spine of an access key inserted in the lock and turned from the locked position as illustrated in Figure 4 to the actuated position as in Figure 4-A to provide a pattern of open and blocked passages that is decoded into a key identification signal. A series of light emitters or sources 24, provided with power through the plug or connector 30 from the batteries or other power source 31 (Figure 2) , are placed so that their emitted light passes into the apertures and openings on one side of the lock.

A series of light detectors 25 are placed on the other side of the lock such that, in the instance of an open passage, light from the emitter falls on a respective detector. The light emitters and light detectors are illustrated in Figure 3 as positioned upon opposite legs of

a mounting bracket 32. In the case of the absence of a notch in the key, causing the light to be blocked, the light from an emitter will not fall on the respective detector.

This pattern of passed and blocked light is received by suitable detection circuitry illustrated in Figure 5 at 26 for use in amplification and other desirable conditioning of the signal for use by suitable decoding circuitry 27 if necessary. The decoding circuitry is connected through the plug 30 (Figure 4) or connector to yield an identification symbol or number useful by a computer 33 (Figure 5) and the like to display or record indicating the identity of the person operating the access key. The limit of identification numbers or symbols is controlled as a binary function of the number of passages in the lock body. Four passages would yield sixteen possible symbols while eight passages would yield two hundred fifty-six possible symbols. Some of the identification bits could be used for parity or error checking for correction, and others, specifically the all light blocked and all light passed conditions could be interpreted as not allowed states. These two particular identifications could relate respectively to an unencoded key and a possible lock picking attempt. Suitable electronics may be used to sound an alarm, make notification, or record of the event. Figure 1 illustrates a plurality of such keyed alike access keys (B) having like

projections 17. Each key B is encoded with a distinctive pattern of notches 19 for passing light to detectors 25 when in alignment with the apertures in the lock.

An additional light emitter and light detector pair 28 and 29 respectively may be used to detect actuation of the lock. Light from the emitter is reflected from the cam as the lock cylinder or plug is rotated as illustrated in Figures 3 and 5-A. Reflected light is picked up by the light detector 29 which actuates a suitable electrical signal indicating that the lock has been opened. This device may act, for example, as a power saver when associated with the detection or other circuitry, not shown, as a means for actuating same, permitting the other circuitry to remain in a dormant state or state of reduced activity, until needed.

If desired, other forms of sensing or detecting means for sensing the pattern of the notches and the like by which the access keys are encoded may be provided. Mechanical switches which may be actuated by the presence or absence of a notch or suitable magnetic effect devices and photo¬ resistive materials may be provided opposite a suitable switch operator for sensing or reading the pattern or code on this key.

It is thus seen that a keyed alike lock with multiple key identification capabilities has been provided. The lock may be a conventional mechanical tumbler lock operated by a

key. The key is encoded preferably by providing a spine of the key fitted with notches. Several light beams are ⁷ directed through holes in the body of the lock toward several photo-detectors. Some of the beams are blocked by the spine of the key where no notches are present. Other beams are allowed, by the presence of a notch, to pass to the photo-detectors. The photo-detected pattern of present or blocked light beams which is decoded identifies the key being used to operate the lock and such information may be utilized as by a computer.

While a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.