Background of the Invention
1. Field of the Invention
This invention relates, in general, to means for initiating an electrical signal within an otherwise-inaccessible region by the manipulation of a shaft passing into the region, and in particular, to an electronic dial combination lock.
2. Description of the Related Art
There is an ongoing need for means for authorized personnel to access otherwise-inaccessible security regions easily, such as are found in safes, lock-boxes, storage rooms and the like. One such means is the well-known combination lock which typically comprises a plurality of tumbler wheels coaxially journalled on a rotating spindle which projects outwardly from the lock and is manipulated within one degree of freedom (rotational) through a predetermined, sequential series of rotations to operate a bolt within the lock. A variation on such a lock is discussed in U.S. Pat. No. 3,968,667.
With the advent of miniaturized components and digital logic circuitry, the art has seen an increasing requirement for means for producing sequential signals which may be utilized as a means for unlocking a protected region. One such sequential switch means having two degrees of movement is disclosed in my U.S. Pat. No. 3,758,734, while a second such means is illustrated in my U.S. Pat. No. 3,702,070.
An electronic combination lock which utilizes a sequential signal producing means having one degree of movement to actuate a bolt to unlock a door is disclosed in U.S. Pat. No. 4,038,846 to Klann.
These prior art devices share certain drawbacks: Some of the electronics for initiating the electrical signal are mounted externally of the protected region, and hence, are subject to a greater degree of tampering by unauthorized personnel.
A second drawback is that they are not easily adapted to retrofit existing security regions which utilize conventional, mechanical combination locks for electrical actuation.
Summary of the Invention
It is therefore an object of the present invention to provide an apparatus for initiating an electrical signal within an otherwise-inaccessible region by the manipulation in two degrees of a shaft passing into the region in a predetermined, sequential order corresponding to a code or combination, in which the electronics for initiating the signal are contained entirely within the region, and which may be provided within an electronic dial combination lock for the operation of a bolt within a door providing access to the region.
It is a further object of the present invention to provide such an electronic dial combination lock that can be used to retrofit existing mechanical combination lock installations easily.
These and other objects of the present invention are preferably accomplished by the provision of a shaft having one end extending out of the security region, as well as means within the region for mounting the shaft for movement having two degrees of freedom, including means for biasing the shaft to a normally outward position relative to the region. On the external end of the shaft are means for manually-positioning the external end of the shaft at a plurality of discrete, evenly-spaced, identified angular positions, such as a dial, and for displacing the shaft axially into the region for a given distance against the shaft biasing means. On the other end of the shaft is radial arm having one end attached to the internal end of the shaft at an angular position corresponding to one of the discrete shaft angular positions, the arm having a push pin at the other end extending rearwardly and parallel to the shaft. Disposed in a planar, evenly-spaced, circular pattern perpendicular and centered on the shaft is a plurality of distinct pressure-sensitive switches which oppose the push pin such that, when the shaft is displaced axially into the region at one of the discrete, angular positions, one of the switches is contacted uniquely by the push pin to generate an electrical connection. Circuit means are contained in the region for sensing the making of the distinct electrical connections and for detecting when a given subset of the connections has been made in a predetermined, sequential order corresponding to the code or combination of the device, and further include means for generating an electrical signal, such as a voltage, upon detection of the proper code, which may be pre-set by the user. In a narrower embodiment, the signal of the preferred apparatus may be used to actuate a solenoid for the ultimate retraction of a bolt, such as in the door of a safe.
Skilled practitioners will obtain a more complete understanding of the present invention from a review of the following detailed description of a preferred embodiment, when taken in conjunction with the appended drawings, of which the following is a brief description.
Brief Description of the Drawings
FIG. 1 is a top view of an electric combination lock in keeping with the subject of the present invention, in which section II--II is taken;
FIG. 2 is a sectional view taken into the rear of the lock, as revealed by the section II--II taken in FIG. 1;
FIG. 3 is a sectional side view into the lock, as revealed by the section III--III taken in FIG. 2;
FIG. 4 is a partial, detailed section taken from FIG. 3 showing the lock's spindle displaced in the direction of the arrow;
FIG. 5 is a view into the rear of the lock similar to FIG. 2 showing the lock's fence lever engaged with the lock's cam wheel;
FIG. 6 is a front view of a solenoid actuating lever;
FIG. 7 is an exploded view of the lock from the front; and
FIG. 8 is an exploded view of the lock from the rear.
Description of the Preferred Embodiments
An exemplary preferred electronic combination lock 10 in keeping with the present invention is illustrated in expanded form in FIGS. 7 and 8. Lock 10 preferably mounts to the inside surface of a door 11 protecting a security region, such as the contents of a safe.
Lock 10 includes a housing 12 which mounts to the rear surface of door 11 by conventional fastening means, such as screws and the bosses illustrated.
Housing 12 includes a close-fitting, rear cover 14, which provides access to the contents of housing 12 from the rear of lock 10.
Slidably-retained within housing 12 is a conventional bolt 16 which engages within a recess 18 contained within the wall 20 of the region protected by lock 10 (See FIGS. 1 and 2).
A fence lever 22 has one end 24 pivotally attached to bolt 16, and a second end having a nose part 26 formed thereon. A transversely-extending fence member 28 extends rearwardly of fence member 22 intermediate of the two ends.
A shaft or spindle 30 passes through the front of housing 12 and through door 11 to extend outwardly from the protected region such that an external end is accessible from outside the region, while an internal end is contained within housing 12. Shaft 30 is journalled within housing 12 for movement in two degrees, i.e., for both rotational and axial displacements relative to housing 12. Mounted to the external end of shaft 30 is a cylindrical dial 32 having a plurality of evenly-spaced radial divisions 33 marked on its circumference and a knurled knob 34 for two degree manipulation of dial 32, and hence, shaft 30.
An opaque dial ring 36 snaps over dial 32 onto mounting plate 38, which, in turn, mounts to the front surface of door 11. Dial ring 36 obscures view of the divisions 33 marked on the surface of dial 32 except for those immediately below a transparent window 40 contained in dial ring 36. Transparent window 40 additionally contains a fixed index mark 42 such that shaft 30 may be aligned at a known angular position by aligning corresponding radial division marks 33 below index mark 42. Window 40 is adapted to obscure view of the division marks 33 except from a position immediately in front of dial 34, to prevent unauthorized surveillance of manipulation of dial 34, i.e., from the side.
Biasing means 44, such as a spring, serves to bias dial 32, and hence shaft 30, to an axially-outward position relative to housing 12.
Mounted to the internal end of shaft 30 for coaxial rotation and translation therewith is a cam wheel 46. Cam wheel 46 contains a gate 48 in its circumference which is disposed to engage nose part 26 of fence lever 22 at a given angular orientation of cam wheel 46 upon rotation of shaft 30 in one direction, and to disengage nose part 26 upon rotation in the other direction.
Located on the rear surface of cam wheel 46 is a rearwardly-extending push pin 50 at an angular position corresponding to one of the discrete shaft positions and at a given radial position relative to the axis of shaft 30.
Coaxially-mounted about shaft 30 within housing 12 is a solenoid-driven, fence-lever-positioning member 52 (See FIG. 6). Positioning member 52 contains a central aperture 54 permitting it to be mounted coaxially with shaft 30 and retained in place within housing 12 by retaining rings 55. Positioning member 52 pivots about central aperture 54 between two positions, in one of which a camming surface 56 engages the fence 28 of fence lever 22 to prevent fence lever 22 from engaging cam wheel 46. In a second position, fence lever 52 is pivoted such that camming surface 56 rotates away from fence 28, thereby permitting fence lever 22 to engage cam wheel 46.
Positioning member 52 is toggled between the two positions by means of an electrical solenoid 60 having a reciprocating armature 62 engaging an aperture 58 in positioning member 52. In the de-energized state, solenoid 60, and hence positioning member 52, assumes the first position illustrated in FIG. 2, in which camming surface 56 underlies fence 28, thereby precluding engagement of fence lever 22 with cam wheel 46. When energized, the solenoid 60, and hence positioning member 52, assume the second position illustrated in FIG. 5, in which positioning member 52 has disengaged fence 28, permitting fence lever 22 to engage nose part 26 in circumferential gate 48 of cam wheel 46. In this configuration, subsequent rotation of shaft 30 causes bolt 16 to withdraw from recess 18, thereby unlocking door 11.
Both bolt 16 and solenoid 60 are biased by spring means (not illustrated) toward the closed position, such that, upon rotation of dial 32 and spindle 30 in the opposite direction, fence lever 28 is cammed upwardly and away from cam wheel 46, whereby positioning member 52 re-engaged below fence member 28 and bolt 16 reengages recess 18.
Mounted in the rear of housing 12 in a plane generally normal to the central axis of spindle 30 and spaced apart from cam wheel push pin 50 by a given distance is a circuit component mounting board 70. Mounted thereon is a plurality of distinct, pressure-sensitive switches opposing cam wheel push pin 50 in an evenly-spaced, circular pattern centered on the axis of spindle 30 at a radial position coincident with that of push pin 50 and at angular positions corresponding to those of push pin 50 when spindle 30 is indexed at the discrete, identified angular positions. In the exemplary preferred embodiment, pressure sensitive switches 72 comprise a plurality of discrete, thin-film touch pads of a type known in the art. However, in some applications, thick-film switches or mechanical switches may be preferably substituted.
Each pressure-sensitive switch 72 is capable of making a distinct electrical connection when contacted by push pin 50, the operation of which is illustrated best in FIGS. 3 and 4. FIG. 3 illustrates shaft 30 in the outwardly-biased position. Rotation of dial 32 to an identifed angular position below index mark 42 aligns push pin 50 uniquely with one of the arrayed pressure-sensitive switches 72. If shaft 30 is then axially displaced into lock 10 by the operator at this angular position, as illustrated in FIG. 4, push pin 50 contacts its corresponding pressure-sensitive swith 72 and generates a unique electrical connection. In this regard, it may be desirable to provide means, operative when shaft 30 is pushed axially into housing 12 at any arbitrary angular position, for guiding shaft 30 into rotational alignment with the nearest of the discrete, identified angular positions, and which is otherwise inoperative upon rotation of dial 32. This preferably is accomplished by the provision of a pair of toothed wheels (not illustrated), each having teeth on opposing faces which intermesh in a plane generally normal to the axis of shaft 30, one of the wheels being mounted to the shaft, the other being axially-spaced and rotationally-fixed relative thereto, e.g., to the front of mounting ring 38, wherein the teeth are sized and disposed on the wheels such that, when shaft 30 is pushed axially into housing 12 at any given angular position, the teeth intermesh at an intermediate axial position to align shaft 30 with the division mark 33 nearest to index mark 42 when dial 34 is pressed home.
Mounting board 70 additionally provides a convenient vehicle for mounting and interconnecting with pressure-sensitive switches 72 of circuit means 74 within housing 12 for sensing the making of the electrical connections at pressure-sensitive switches 72 and for detecting when a given subset of the connections has been made in a predetermined, sequential order corresponding to the code, or combination, of the apparatus, and for generating an electrical stimulus, or signal, such as a voltage, upon the detection thereof. In the exemplary lock 10 illustrated, the electrical event initiated is a voltage to actuate solenoid 60, and circuit means 74 includes timing means for holding solenoid 60 in the open position for a period of time sufficient to permit the operator to rotate dial 32 and withdraw bolt 16 from recess 18 before solenoid 60 is de-energized.
Circuit means 74 may additionally include tamper-resistant logic, e.g., so-called "penalty" functions, i.e., those which impose consecutive delays of increasing amounts of time before solenoid 60 can be actuated upon the inputing of an improper code sequence, such as would be initiated by an unauthorized intruder attempting a the application should be limited only by the claims appended hereto.