Showcase Lock for Sliding Doors

The present invention relates to a showcase lock for by-pass type sliding doors such as the sliding glass doors used in glass showcases. Such showcase locks generally include an elongated keeper that can be attached to the inner door and a separate lock member that is adjustable along the keeper to lock the doors in a closed position. Showcase locks of the type shown in U.S. Pat. Nos. 2,050,696; 2,172,208 and 2,878,663 require some clearance between the keeper and the inner panel to allow mounting of the lock on the keeper, and the keepers in these patents are attached at only one end by a clip or clamp to the edge portion of the inner closure panels. Clip-on type keepers can move or shift relative to the inner door and present problems not only because they can become tilted or even dislodged from the inner door during installation, but also because they can cause chipping of the edges of glass doors, if they are not properly positioned when the lock is installed. My prior U.S. Pat. No. 3,931,723, discloses a showcase lock in which the keeper is adhesively secured along its entire back side to the face of the inner panel so that it cannot move or shift relative to the inner panel. However, my prior patent required a special plunger type lock in which the lock plug could be moved both axially and rotationally to first shift the latch toward the keeper and then turn the latch into locking engagement with flanges on the keeper.

It is an object of this invention to provide a showcase lock having an improved arrangement for slidably mounting the lock on the front side of the keeper for locking in adjusted positions therealong whereby the back side of the keeper can be adhesively bonded to the face of the door.

Another object of this invention is to provide a showcase lock for sliding doors in which the keeper has a row of stops intermediate its side edges and the lock has an improved latch and latch actuator for moving the latch into and out of engagement with the stops in response to turning of a key operated plug.

Still another object of this invention is to provide a showcase lock for sliding doors in which the lock is movably retained by a chain on one of the doors when not in use.

Other objects of this invention are to provide a showcase lock for by-passing type doors which can be economically manufactured, which can be easily installed on the doors without use of tools, and which substantially eliminate chipping or breaking of glass type closure panels by the showcase lock.

Further objects of the invention will be apparent from the following description when taken in connection with the accompanying drawings wherein:

FIG. 1 is a fragmentary perspective view of a showcase embodying the present invention and shown mounted on a pair of by-passing type doors;

FIG. 2 is a fragmentary horizontal sectional view showing the lock and keeper applied to by-passing type doors;

FIG. 3 is a transverse sectional view taken on the plane 3--3 of FIG. 2;

FIG. 4 is a transverse sectional view taken on the plane 4--4 of FIG. 2;

FIG. 5 is a fragmentary horizontal sectional view illustrating mounting of the lock on the keeper;

FIG. 6 is a bottom plan view of the lock taken on the plane 6--6 of FIG. 5;

FIG. 7 is a sectional view taken on the plane 7--7 of FIG. 5; and

FIG. 8 is a sectional view taken on the plane 8--8 of FIG. 5.

The lock of the present invention is generally adapted for use on by-passing type doors and particularly for use on sliding glass doors of the type commonly used in glass showcases and the like. The lock is shown applied to outer and inner by-passing type doors 10 and 11 which are respective slidable on outer and inner parallel tracks. Various different trackways can be used to slidably support the by-passing type doors, some of which trackways are arranged to directly receive the edges of the doors and the others of which trackways are arranged to receive frame members on the edges of the doors. In the embodiment illustrated, metal frame members 13 and 14 are attached to the outer and inner doors 10 and 11 respectively and contain rollers (not shown) which engage outer and inner trackways 15 and 16 to slidably support the doors for endwise movement. Trackways are also provided at the upper edges of the doors to maintain the same in spaced parallel relation and the upper trackways are usually in the form of downwardly opening channels that slidably receive either the edge of the doors or frames attached to the doors. The details of construction of the trackways for slidably supporting the doors forms no part of the present invention and further detailed description and illustration is deemed unnecessary.

The showcase lock in general includes a keeper 21 which is mounted on the inner door 11 and a lock 22 which is slidably mounted on the keeper and engageable with the edge of the outer door 10, to lock the doors in a closed position. The keeper 21 is in the form of an elongated plate 23 having a pair of keeper flanges 24 along opposite side edges and projecting inwardly toward each other and spaced from the side of the keeper plate to define a pair of opposed lengthwise extending grooves 25 that open toward each other. The keeper plate has a row of stops located substantially medially between the side edges and, in the preferred embodiment shown, the plate has a row of openings 26 at spaced locations therealong which are separated by intermediate bar segments 26a providing the aforementioned stops. The keeper has transversely extending flange 28 at one end engageable with the edge of the inner door 11 to aid in locating the keeper on the inner door and to also provide a positive abutment to limit movement of the keeper in a direction away from the edge of the inner door. The keeper plate is longer than the keeper flanges to provide a plate portion 23a at the end of the keeper remote from the flange 28, which plate portion extends beyond the end of the keeper flanges and is coplanar with the remainder of the keeper plate for guiding the lock into the grooves in the keeper plate. In the preferred embodiment illustrated, the keeper plate is adhesively bonded to the inner panel 11 to remain permanently affixed to the panel. The adhesive is preferably in the form of a double sided pressure sensitive adhesive tape indicated at 30. Alternatively, an adhesive coating could be applied directly to the attaching face of the mounting plate. The actual thickness of the adhesive layer has been exaggerated somewhat in the drawings for the purpose of illustration, and the adhesive layer is preferably made only sufficiently thick to accommodate minor irregularities and to assure a good bond between the mounting plate and door.

The lock 22 includes a housing 35 that is adapted to be slidably mounted on the keeper 21. The housing is conveniently formed by molding and, as shown, has a generally rectangular configuration with opposed side walls 36, 37, opposed end walls 38, 39, top wall 40 and bottom wall 41. A lip 42 is preferably provided to extend laterally from the end wall 39 and spaced from the bottom wall 41 a distance sufficient to overlie the outer face of the outer panel 10, when the lock is mounted on the keeper as shown in FIG. 2. The housing has a plug bore with its axis perpendicular to the bottom wall 41 and a lock cavity 45 at the inner end of the plug bore. A face plate 46 is attached by fasteners 47 to the bottom wall of the lock housing and extends across the lock cavity 45. The face plate is preferably formed of a thin metal plate and opposite edge portions 46a of the face plate extend outwardly of the adjacent side wall portions of the lock housing to provide a pair of parallel housing flanges disposed in a common plane and projecting outwardly from each other. The face plate 46 has a thickness slightly less than the depth of the grooves 25 to be slidably received therein. As best shown in FIGS. 3 and 4, the side walls 36 and 37 have lower portions 36a and 37a that are offset inwardly from the main portion of the side walls, to provide clearance for the keeper flanges 24. While the lock housing can be molded of metal, it is preferably molded of an impact resistant plastic to reduce the likelihood of chipping or breaking the edge of the glass when it abuts against the outer panel 10, and to also reduce the overall weight. The housing may, for example, be molded of ABS plastic which can be coated as by vapor plating in different colors such as gold, bronze, alumninum.

A key operated plug 51 is mounted in the plug bore 44 for turning movement under the control of a key 52. The plug can be either of the disk tumbler or pin tumbler type and is herein shown of the disk tumbler type having a plurality of disks 53 mounted therein for movement cross-wise of the plug and having projections 53a adapted to engage longitudinally extending grooves 44a and 44b in the plug bore, when the plug is in its lock and unlock positions respectively. The disk tumblers are yieldably biased outwardly by springs (not shown) to engage the grooves in the plug bore and lock the plug against turning. The disks are retracted into the plug when the proper key is inserted into the plug so that the lock plug can be turned between its lock and unlock positions.

The plug has a peripheral rim 51a at its outer end rotatably received in a complementary groove in the outer end of the plug bore, to limit inward movement of the plug. The lock cavity 45 has a somewhat larger cross-section than the plug bore to define a shoulder 56 at the inner end of the plug bore. The lock cavity is preferably of generally circular cross-section with recesses 58 and 59 at opposite sides of the lock cavity defining relatively parallel guide walls 58a and 59a respectively disposed perpendicular to the lower end face 41 of the lock housing. A latch is provided in the lock cavity and comprises a generally U-shaped spring member 61 conveniently formed of flat spring steel stock and having an elongated latch arm 61a and an elongated actuator arm 61b interconnected by a bight portion 61c. The free end of the latch arm terminates in a latch nose having a cam face 61d and an abutment face 61e. The U-shaped spring member is mounted in the plug cavity with the actuator arm 61b extending crosswise of the axis of the plug bore adjacent the inner end of the plug 51 and with the ends of the actuator arm extending into the recesses 58 and 59 to be guided by the spaced walls 58a and 59a respectively. The latch arm 61a also extends crosswise of the axis of the plug bore and is spaced relatively farther from the inner end of the key operated plug, and a fulcrum 64 is provided for mounting the latch arm for rocking movement about an axis intermediate the ends of the latch arm and crosswise of a plane through the latch and actuator arms. The fulcrum 64 is conveniently formed by striking a tab from the face plate and bending it upwardly to a level above the face plate to form a fulcrum at the upper edge thereof. The tab is preferably notched to provide projections at opposite ends of the fulcrum for laterally retaining the latch arm in position. An opening 65 is provided in the face plate adjacent the free end of the latch arm to allow the latch nose to move into and out of the lock cavity.

A cam 68 is provided on the inner end of the key operated plug and engages the actuator arm 61a to rock the actuator arm and latch arm between a lock position as shown in FIG. 2 and a release position as shown in FIG. 5. The cam member 68 is attached to the inner end of the key operated plug 51 for turning therewith and, conveniently, the plug 51 can be formed with integral projections 51b (FIG. 3) at its inner end that extend into countersunk openings 68a in the cam member and which can be riveted or spun over to provide head as shown in FIG. 3 for retaining the cam member on the plug. The cam member can be formed of metal or a suitable plastic material such as ABS and preferably has a diameter larger than the diameter of the plug bore to engage the shoulder 56 and limit outward movement of the plug. The cam member 68 has a cam face 68a that is inclined at an acute angle to the axis of the plug and a disk 69 is preferably interposed between the cam face and the actuator arm 61b to prevent direct rubbing contact between the cam and actuator arm. The disk is conveniently formed of the same material as the housing to allow free rotation of the cam relative to the disk. As will be seen, when the key operated plug is in its lock position shown in FIG. 2, the actuator arm is tilted downwardly toward the nose end of the latch arm and the latch arm is correspondingly rocked about the fulcurm 64 to its latch position in which the latch nose extends through the opening 65 in the face plate. When the plug is in its lock position, the latch nose is yieldably biased outwardly of the face plate and will project into an opening in the keeper plate that is aligned therewith. The latch arm will yield and the cam face on the latch nose will cam the latter out of the opening in the keeper plate, when the lock is pushed toward the edge of the outer door, that is to the right as shown in FIG. 2, so that the latch member will allow the lock to "rachet" into its fully locked position. The stop face on the latch nose, however, provides a sharp abutment which engages the cross bars between adjacent openings to prevent retrograde movement, that is movement of a lock toward its release position. When a key is inserted into the plug, it can be turned to its release position shown in FIG. 5 in which the cam 68 tilts the actuator arm 61b downwardly in a direction away from the latch nose 65, to thereby rock the latch arm in a direction to raise the latch nose as shown in FIG. 5. When the latch nose is retracted into the lock cavity, the lock housing can be moved along the keeper in a direction away from the outer panel to disengage the lock housing from the keeper.

The lock 22 is completely separable from the keeper plate 21 and provision is advantageously made for movably retaining the lock on the outer door 10, when the lock is not in use. As best shown in FIG. 1, an elongated flexible element such as a chain 71 is provided with pads 72 and 73 at its opposite ends. One pad 73 has a generally flat mounting face for mounting on the outer panel 10 and a pressure sensitive adhesive is applied to the mounting face to facilitate attachment of the pad to the outer panel. The other pad is shaped to conform to a wall portion on the lock housing 22. In the embodiment illustrated, the lock housing has flat side walls and the pad 72 is made flat, it being apparent that the pad 72 could be formed with an arcuate configuration for use with lock housings having a cylindrical side wall. The pressure sensitive adhesive is preferably provided by a double faced pressure sensitive adhesive tape which is affixed to the respective pad face. A release covering is provided on the outer face of the pressure sensitive adhesive tape and which can be removed prior to installation.

From the foregoing it is thought that the construction and use of the lock will be readily understood. The keeper plate is adhesively bonded to the inner door 11 and is intended to remain permanently attached to the inner door. This avoids shifting of the keeper plate relative to the inner door and minimizes the likelihood of chipping or breaking of the glass. The keeper plate provides inwardly opening grooves at its outer side and the keeper plate extends beyond the channels so that the lock can be positioned against the extending end portion of the keeper plate to facilitate guiding of the lock flanges into the channels on the keeper plate. The lock is advantageously formed of an impact resistant plastic material to minimize the likelihood of chipping or breaking the glass of the outer panel, and to also reduce overall weight so that it is less likely to break the glass when suspended by a flexible retainer such as 71. The generally U-shaped latch member is mounted so that it can tilt or rock about a pivot axis that extends crosswise of the plug bore, and the cam on the plug engages the actuator arm 61b to move the same between a lock position in which the actuator arm is inclined downwardly toward the latch nose as shown in FIG. 2, and a release position in which the actuator arm is inclined downwardly in a direction away from the latch nose as shown in FIG. 5. When in its lock position, the latch arm is resiliently biased in a direction outwardly of the housing, but the latch arm can cam over the abutments on the keeper when the lock is moved toward its lock position against the outer panel 10. The latch nose, however, provides a sharp abutment which prevents retrograde movement of the lock, until the key operated plug is rotated to its unlock position.