Lock With Universal Key Ejector

Abstract

A tumbler lock having associated therewith a spring-biased key ejector which is effective to eject the key in all angular positions of the plug, i.e., in the unlocked position, the locked position, or any intermediate position so that at no time may the key be left within the lock.

Description

The present invention relates to a key-controlled lock of the type in which a plug having a keyway therein is rotatable within a lock cylinder, the usual tumblers being employed to lock the plug against rotation with respect to the encompassing lock cylinder. The invention is specifically concerned with key-ejecting means whereby the key is at all times biased against forward movement in the keyway in the plug so that at any time the key is released, regardless of whether the plug be in its locked position, its unlocked position, or in any intermediate position, it will be automatically ejected from the keyway and consequently, from the lock as a whole.

The improved lock comprising the present invention is designed primarily for use in connection with a refrigerator cabinet, especially a cabinet of the deep-freeze type. Such a cabinet usually is kept in a basement where it is accessible to children, and there are on record numerous instances of fatalities arising from children at play and in the possession of a key inadvertently left in a freezer cabinet. Such instances have led to recent regulations in certain states that not only shall a freezer cabinet lock intended for home use be devoid of a spring latch which would permit a given cabinet to become locked automatically upon closing the door or lid itself, but also that a cam type lock which requires a key for the locking thereof shall be provided with facilities whereby the key shall be automatically ejected from the lock.

The present invention goes a step further in this direction of precautionary safety in that it provides a lock in which it is impossible to leave the key within the keyway in the rotatable plug regardless of whether the plug be in its unlocked position, its locked position, or in any intermediate position. Heretofore, a lock of the key-ejecting type has been designed primarily for automotive use and is so constructed that ejection of the key takes place only when the rotatable plug of the lock is in either its locked or its unlocked position. Such a lock, if applied to a freezer cabinet could, conceivably, be left in a partially locked condition where the key would be readily available to a child.

A specific limitation that is attendant upon the construction and use of a prior key-ejecting lock resides in the use of a key-loading spring which necessitates the use of considerable manual pressure to overcome its biasing action during insertion of the key into the keyway in the plug of the lock. Space limitations have dictated that such a spring be provided with a relatively short length if it is coaxially disposed with respect to the lock cylinder or that it be offset in a special chamber alongside of the cylinder. A short spring obviously is quickly loaded to capacity and thus requires considerable force to drive the key to its home position for tumbler-actuating purposes while an offset spring results in a bulky and expensive lock structure as a whole.

The present invention obviates the above-noted limitations that are attendant upon any prior key-ejecting lock, and toward this end, it contemplates the provision of a lock in which the key ejector spring is of relatively small diameter and relatively long, as well as being coaxial with the rotatable, tumbler-equipped plug and its surrounding cylinder. The difficulties which ordinarily would be associated with the installation of such a long spring within the confines of the lock are obviated by making the plug in two separable parts so that the spring may be installed in a comparatively deep bore in one of the lock parts, the two parts assembled upon each other, and the assembled plug then inserted in the lock cylinder and held in place by a snap ring or the like.

Insofar as ejection of the key in all angular or rotational positions of the plug within the cylinder is concerned, the use of constantly diminishing bitting on the key allows key ejection at any time inasmuch as inward tumbler displacements which are maintained by the sliding action of the outer ends of the tumblers against the interfacial cylindrical wall of the lock cylinder do not place the inside edges of the tumblers in the path of high bitting on the key.

The provision of a tumbler lock of the key-ejecting type such as has briefly been outlined above and possessing the stated advantages, constitutes the principal object of the present invention.

The provision of a key-ejecting lock which is appreciably simpler in its construction than other key-ejecting locks designed for the same general purpose; one which is comprised of a minimum number of parts and, therefore, is unlikely to get out of order; one which is capable of ease of assembly for purposes of inspection or repair of parts; one which is rugged and durable and will, therefore, withstand rough usage and one which, otherwise is well adapted to perform the services required of it, are further desirable features which have been borne in mind in the production and development of the present invention.

Other objects and advantages of the invention, not at this time enumerated, will become apparent as the nature of the invention is better understood from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter described and more particularly defined by the claims at the conclusion hereof.

In the accompanying single sheet of drawings forming a part of this specification, one illustrative embodiment of the invention is shown.

In these drawings:

FIG. 1 is a longitudinal sectional view taken centrally and longitudinally through a key-ejecting lock embodying the principles of the present invention and showing the key in position within the keyway in the rotatable plug of the lock;

FIG. 2 is a longitudinal sectional view similar to FIG. 1 but showing the key released, and as a result thereof, ejected from the keyway in the lock plug;

FIG. 3 is a longitudinal sectional view taken on the line 3--3 of FIG. 2;

FIG. 4 is a fragmentary front end view of the lock;

FIG. 5 is a transverse sectional view taken on the line 5--5 of FIG. 3; and

FIG. 6 is a transverse sectional view taken on the line 6--6 of FIG. 3.

Referring now to the drawings in detail, a lock embodying the present invention is designated in its entirety by the reference numeral 10 and includes a tubular lock cylinder 12 having an enlarged head 14 at its forward end, the head presenting a rearwardly facing radial shoulder 16. The outer periphery of the cylinder 12 may be threaded to the end that the cylinder may be secured in a lock-receiving opening in a cabinet door (not shown) by means of a nut 18 which draws the shoulder 16 firmly against the front side of the door.

The cylinder 12 is provided with a longitudinally extending plug-receiving bore 20 in which there is rotatably disposed a two-part separable composite plug 24 (see FIG. 3) including a front part 26 having diametrically slidable spring-pressed plate tumblers 28 associated therewith, and, in addition, a longitudinally extending keyway 30 for receiving a single bitted key 32 which is configured to displace the plate tumblers 28 and enable rotation of the composite plug 24 in the usual manner of a plate tumbler type of lock. The key 32 is provided with special bitting 34 which is of a progressively diminishing nature and, hence, is non-undulatory. Such bitting performs a particular function in connection with the key-ejection facilities of the lock as will be described subsequently.

The forward region of the bore 20 is provided with a series of four longitudinally extending grooves 36 (see FIG. 5) which are disposed 90.degree. apart. One of these grooves is adapted to receive certain ends of the plate tumbler 28 when the plug 24 is turned so that the lock is in its locked position, while another and adjacent groove is adapted to receive said certain ends of the plate tumblers when the plug is turned so that the lock is in its unlocked position. When the key 32 is fully disposed in the keyway 30, the tumblers are retracted so that the plug 24 may be rotated.

The front end of the lock cylinder 12 has a counterbore 40 in which is seated a radial rim flange 42 on the front plug part 26. The rear side of the rim flange 42 is relieved along one-half of its circumferential extent to provide a pair of radially extending shoulders 44 and 46 (see FIG. 4) which are designed for cooperation with a pair of lugs 48 and 50 in limiting the extent of plug rotation to 90.degree..

The key 32 is provided with the usual longitudinal grooves 52 and 53 on opposite sides thereof and they cooperate with longitudinally and inwardly extending ribs 54 and 55 which are formed on the front plug part 26 and extend along the keyway so that only a key having a particular pattern of side grooves may be used in connection with the lock.

The general arrangement of parts thus far described is more or less conventional and no claim is made herein to any novelty associated with the same, the novelty of the present invention residing rather in the key-ejecting mechanism by means of which the key 32 is prevented from remaining in the keyway 30 regardless of the angular position of the plug 24 with respect to the cylinder 12.

The composite plug 24, in addition to the front part 26, comprises a rear part 60 which is of elongated design and is connected to the front part 26 for rotation in unison therewith by means of a transverse tongue and groove connection including a T-head and T-slot interlock 62 (see FIG. 3), the union being such that in the absence of any obstruction the two plug parts may be displaced laterally by a sliding movement between the parts and then separated.

Slidably disposed in the keyway 30 is a key ejector element 64 which resembles to a certain extent a forward or distal fragment of the key bitting 34. This key ejector element is capable of sliding longitudinally in the keyway 30 by reason of a longitudinal groove 66 which is formed therein on one side only and conforms to the key groove 52. Said key ejector element 64 is yieldingly biased forwardly in the keyway 30 by means of an elongated helical compression spring 70 which is nested within a small but deep longitudinally extending and centrally disposed socket 72 in the rear plug part 60. Said socket has side grooves 73 which constitute clearance regions for sliding movement of the key ejector element 64 when the latter is pushed rearwardly by the key 32. A snap ring 74 in an annular groove 75 in the outer periphery of the rear plug part 60 cooperates with the rear end surface of the cylinder 12, and in combination with the rim flange 42, maintains the composite plug 24 in position against axial shifting with respect to said cylinder.

The rear end of the rear plug part is provided with the usual non-circular, screw-threaded, reduced portion 76 for reception thereover of a comformably shaped opening 78 in the inner end of a radially extending locking cam 80. A nut 82 holds the cam in plate on the reduced portion 76, the cam 80 being designed for cooperation with a suitable locking shoulder on the cabinet in the vicinity of the door to which the lock 10 is applied.

In the operation of the herein described lock 10, assuming the lock to be in its locked position, insertion of the key 32 into the keyway 30 will effect end-to-end engagement between the key and the key ejector element 64, thereby forcing the latter rearwardly in the side grooves 73 and compressing the spring 70,while at the same time, subjecting the key to a forward biasing action against the exerted manual pressure. As soon as the key reaches its home position, the various plate tumblers 28 will assume positions which release the composite plug 24 so that it may be rotated by means of the key in the usual manner of lock operation. This forward biasing action against the key 32 remains prevalent throughout the full extent of turning movement of the plug 24 while it is being turned to its unlocked position and it also remains effective after such position has been reached. By reason of the constant forward bias which is thus applied to the key, and by reason of the fact that the key bitting 34 is of a constantly diminishing stepped and non-undulatory nature as previously set forth, no obstruction is offered to the key so that if, at any time, it is manually released, it will be ejected from the keyway 30.

The fashioning of the lock plug 24 in two interlocking parts facilitates initial assembly of the lock, insertion of the spring 70 in the socket 72 being effected before a union of the front and rear plug parts 26 and 60 is made. Thereafter, by holding the key ejector element 64 retracted in the grooves 73, the T-head and T-slot connection may be effected, and upon release of the key ejector element 64, the extreme front end of the latter moves into engagement with the rib 55 near the front end of the front plug part 26 and prevents further movement of the key ejector so that the latter assumes the position in which it is shown in FIG. 2. Such engagement of the key ejector element 64 with the spline rib 55 takes place by reason of the fact that one side of the key ejector element is devoid of a cooperating side groove. A forwardly presented shoulder 84 on the key ejector element has no function in connection with key ejection, but is provided to facilitate manual retraction of the element during lock assembly and dismantlement operations.

From the foregoing description, taken in conjunction with the accompanying drawings, it will be apparent to those skilled in the art that this invention constitutes a substantial improvement in key-controlled locks having key-ejection facilities, the improvement residing largely in the fact that key-ejection takes place whenever the key is manually released and regardless of whether the lock be in its locked position, its unlocked position, or any intermediate position of plug angularity.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit or scope of the invention. For example, although the exemplary lock shown and described herein is of the plate tumbler type, it is obvious that with but slight modification the key-ejection facilities of the lock may be applied to pin tumbler locks. Furthermore, it is obvious that by utilizing a double-bitted key and causing the plate tumblers 28 variously to be spring-biased in opposite directions, the two pairs of diametrically disposed grooves 36 may be utilized for tumbler-receiving purposes when the plug 24 is in its locked and its unlocked positions, respectively. Therefore, only insofar as the invention is particularly pointed out in the accompanying claims is the same to be limited.

Claims

Having thus described the invention what I claim as new and desire to secure by letters patent is:

1. A lock and key combination comprising a lock cylinder, a plug having a keyway and rotatably mounted in said cylinder, a key receivable in said keyway, spring-pressed tumbler means movable in said plug and cylinder for preventing relative movement between the plug and cylinder when the key is removed from the keyway, a key-ejector element slidably disposed in said keyway and having its front end engageable with the distal end of the key for key-ejection purposes when the latter is inserted in the keyway, said key being formed with a longitudinal groove in one side thereof and the plug being formed with a cooperating longitudinal rib for guiding the key in the keyway, said rib being positioned in the path of forward movement of the key-ejector element and serving to limit the extent of forward movement of which the latter is capable, said key being further provided with tumbler-engaging bitting thereon of a constantly diminishing, non-undulatory nature whereby said tumbler means offers no resistance to key-ejection by said key-ejector element regardless of the rotational position of the plug within the cylinder.

2. A lock and key combination as set forth in claim 1 and wherein the key is formed with a longitudinal groove on the other side thereof, the plug is formed with cooperating longitudinal ribs on opposite sides of said keyway, and the key-ejector element is formed on one side thereof with a longitudinal groove which cooperates with one of said ribs on the plug, the other side of the key-ejector element being devoid of a groove in order that the other rib on the plug is engageable with the forward end of the key-ejector element to limit the extent of forward movement of which said element is capable.

3. A lock and key combination as set forth in claim 2 and wherein the lock cylinder and plug define therebetween a cylindrical interface, the tumbler means includes a plurality of diametrically shiftable plate tumblers which are spring-pressed so as to slide on the interfacial region of the lock cylinder, and said interfacial region is formed with two circumferentially spaced longitudinal tumbler-receiving grooves, one of which receives the tumblers when the plug is in its locked position and the other of which receives the tumblers when the plug is in its unlocked position.

4. A lock and key combination as set forth in claim 1 and wherein said spring means comprises a compression spring which is nested within a longitudinally and centrally disposed socket in the plug, the rear end of the spring bearing against the bottom wall of the socket and the front end thereof bearing directly against the front end of the key ejector element.

5. A lock and key combination as set forth in claim 4 and wherein the plug is of a composite nature and embodies a front plug part and a rear plug part having means releasably securing the parts together in coaxial end-to-end abutting relationship, and the socket within which the compression spring is nested is formed in said rear plug part.

6. A lock and key combination as set forth in claim 5 and wherein said releasable securing means for the front and rear plug parts is in the form of a tongue and groove interlock connection between the parts.

7. A lock and key combination as set forth in claim 6 and wherein said interlock connection comprises a T-head on the rear plug part and a conformable T-slot in the rear end of the front part.

8. A lock and key combination as set forth in claim 5 and wherein the front rim of the lock cylinder is provided with an annular recess therearound, the front end of the front plug part is provided with a rim flange which seats within said annular recess, the rear plug part is provided with an exterior annular seating groove in the vicinity of the rear rim of the rear plug part, and a snap ring seats within said latter groove and, in combination with said rim flange, serves to maintain the plug and lock cylinder in their assembled relation and against relative axial shifting.

9. A lock and key combination as set forth in claim 8 and wherein both the key and the key ejector element are of flat plate-like construction, are at all times coplanar, and the socket in which the compression spring is nested is provided with a pair of diametrically disposed grooves within which the opposite sides of the key ejector element is slidable.