Patent Application
20170122006
This invention concerns locks of relatively light duty, particularly for cabinets, drawers, file cabinets, access panels and similar situations, typically used on office furniture but not on entry doors or other high-security applications such as safes. More specifically the invention encompasses an electronic cam lock that in some embodiments fits a standard cam lock opening.
Metal and wood file cabinets, desk and cabinet drawers, locker doors, access panels and doors, mail boxes, dispensers and other secure situations often utilize relatively simple lock mechanisms known as cam locks. Such cam locks may or may not involve a camming action. In some cases they move other mechanisms that are engaged with the door or drawer of the cabinet or engaged with other mechanisms that are linked to the door and drawer of the cabinet or multiple doors or drawers of the cabinet. In one of the simplest forms, a cam lock on a cabinet door typically fits in a ¾ inch diameter D-shaped or double D-shaped hole and, at the back side of the cam lock cylinder unit, has a metal blade or arm called a cam that rotates when the key is turned, from a position disengaged from surrounding cabinet hardware to a position of engagement in a slot or behind a ledge of the surrounding cabinet hardware. Other locks, such as those for desk drawers, commonly referred to as cabinet locks, involve a camming type action as the key and plug are rotated. The rotation causes a cam or nipple to move a deadbolt linearly to a locking or unlocking position or in the case of a spring loaded latch or deadlatch the rotation causes the cam or nipple to move a latch or deadlatch to unlocking position and removing the key keeps the latch or deadlatch in the extended locked position.
Metal filing cabinets often utilize cam locks, or a variation known as a plunger type lock in which a spring loaded plunger/lock cylinder located in the top horizontal margin of the cabinet, when pushed in, will lock all drawers. The use of a key releases the spring plunger to return to the outward position and unlock the drawers.
Locker and cabinet locks have included electronic locking devices, some of which utilized keypads and some of which utilized IButtons or other ID or non-volatile memory devices which work on contact to release the lock. See, for example, U.S. Pat. Nos. 5,894,277, 5,886,644, 6,655,180 and 6,791,450. The disclosures of all of these patents are incorporated herein by reference.
There is a need for a relatively simple, easily used, reliable and compact electronic lock, preferably a keypad lock but optionally operable by an electronic key, or both, for situations in which typically cam, plunger and cabinet locks were employed, and capable of fitting in a standard opening or bore of a standard cam, plunger or cabinet lock cylinder in a cabinet, door, access panel, mail box, dispenser, etc. and alternatively capable of fitting in a standard shell of a standard cam, plunger or cabinet lock cylinder in a cabinet, door, access panel, mail box, dispenser, etc. This is an objective of the current invention described below.
This invention is an improvement on the locks of U.S. Pat. Nos. 8,490,443 and 8,495,898, both owned by the assignee of the invention, and an improvement over U.S. Pat. No. 8,671,723. The disclosures of all of these patents are incorporated by reference in their entirety.
The current invention is a small, extremely compact cam lock.
The lock is generally similar to those described in the '443 and '898 patents noted above. It is an electronic cam lock for use on a door, cabinet, panel or drawer in a cabinet or furniture that provides ingress and no egress. The locks are of light to medium duty not high security such as safes or entry door. Cam locks are well known in the industry as typically having a rotary member or driver (usually a plug within a cylinder) that is turned by a mechanical key, fitted to the cylinder and which typically has at its inner side a swingable cam for engaging with fixed structure of the file cabinet or the furniture to lock the cabinet. The assignee herein has described electronic cam locks that replace a mechanical key and are of a small size so as to fit in a position of a traditional cam lock, which ordinarily occupies a ¾ inch diameter hole in the panel or cabinet and often fits in a narrow margin. The above-referenced '898 and '443 patents are examples of those electronic cam locks.
The invention further miniaturizes an electronic cam lock for a cabinet or furniture, with a highly efficient construction unknown in previous electronic cam locks.
The lock of the invention has some features similar to those of U.S. Pat. No. 8,671,723 referenced above. However, the current electronic cam lock is more efficiently constructed and with fewer parts and in a housing that takes advantage of space in a key location for receiving a fastener, allowing the lock to be operable at the margin of a file cabinet or other similar office furniture wherein the lock mechanism needs to be near a far edge of the unit. In the electronic cam lock device of the invention, an even smaller size is achieved than the electronic cam locks of the '898 patent referenced above. In one form of the lock, a threaded cylinder extends from the back side of the lock housing, in a standard cam lock size, with a blank plug as a driver that rotates when the knob or handle is permitted rotation by a user. In this version the threaded lock cylinder enables retention of the housing on the panel or drawer by a nut screwed onto the cylinder, in the manner of prior simple mechanical cam locks. A second fastening can be made at an opposite end of the housing (which is elongated in the case of a keypad as access terminal).
However, in the case where only a cylinder plug as a driver extends back from the housing (whether or not secured to the housing or simply engaged for rotation with the front knob or handle), there will be no threaded cylinder shell for use of securing the housing to the furniture. Examples of this are shown in U.S. Pat. No. 8,495,898, FIGS. 6-12. A retaining wafer holding the plug driver in place is not strong enough against pull attacks on the lock unit and an alternative attachment means is required. Because of the lock actuating mechanism, motor and driver being at one end of the lock unit, providing a nut tube or post or cylinder to receive a machine screw at or providing a threaded screw to receive a nut at the bottom of the lock at or near that end might require extending the length of the housing farther beyond the knob or handle. This is in many cases not possible because the driver or plug unit must be close to the left or right edge of the cabinet, or the bottom of a cabinet door. In office file cabinets, for example, a cam lock often acts at the upper right corner of the cabinet. Due to the locking mechanism being placed against the cylinder/plug area in the lock housing, a securement at the right end of the housing is not possible without increasing the lock body height.
With the worm gear drive and the spring actuator employed in the lock of the invention, a space is available among the elements of the actuating mechanism (including the motor, worm gear, a pivot lever and the spring) for positioning a threaded nut tube or post or nut cylinder that can receive a machine screw secured into the nut tube from the back side of the cabinet panel. The nut tube or post is provided in the housing main body or in the back cover plate of the housing, protruding among the components of the actuating mechanism without interference with the locking and unlocking action. The space is provided due to the specific mechanism employed by the invention and is an ideal position for anchoring the lock housing to the panel or cabinet, being directly adjacent to the driver, plug or other rotational cam-driving member.
Further, the lock housing and mechanism of the invention provide for an efficiency of construction and mechanical movement not found in the above-identified prior patents. Instead of an arcuate segment of gear teeth co-acting with a rack of fixed teeth to provide a basis for pivoting of an actuator lever driven by a worm gear, as in U.S. Pat. No. 8,671,723, the mechanism of the invention includes a simple pivot mounting for a worm gear-driven actuator arm. This saves space and provides for economy of parts, assembly and structure. A flexible connection, preferably the lever spring noted above but optionally a different type of spring, extends from the pivoted arm to engage with a slidable blocking pin or plate, to slide that plate to a locking or unlocking position depending on rotation of the motor/worm gear. When in locking position the slidable pin engages in a notch or recess of a rotatable member that is part of the knob or driver assembly. The spring provides for lost motion, to allow the blocking pin to wait for the notch to be rotated back to the locking position.
The electronic cam lock of the invention is of minimal size so as to fit neatly on a file cabinet or other office furniture, with an efficient and reliable lock drive mechanism. These and other objects, advantages and features of the invention will be apparent from the following description of a preferred embodiment, considered along with the accompanying drawings.
The locks in
The plug 32, or another driver that simply comprises a shaft with a cam-engaging feature, cannot be used to firmly anchor the lock housing 24 at that end, as is required. The nut cylinder or tube 30 of the housing is positioned as close as possible to the rotation axis of the knob and driver for this purpose. The ability to place the nut tube close to the axis is an important feature of the invention and is enabled by the arrangement of components in the internal actuation system of the driver as explained below. In this embodiment the nut tube 30 is formed as part of a rear cover 36 of the lock housing.
The mechanical actuating system 44, which is detailed in
The location of the nut cylinder or barrel nut 30 among the mechanical components (including motor 70) of the lock is important in that it enables the fastener 40 (machine screw) to be near the end 24a of the housing without being located beyond the rotational elements 28, 42 and 32. Thus the knob rotation axis can be as close as needed to the end 24a of the housing. In a preferred embodiment the fastener 40 is located (on centers) no more than about 13/16 inch from the axis of rotation of the driver or plug 32, in the proportions generally as shown in the drawings. In fact the fastener can be even closer, with the actuating mechanism 44 closer to the driver axis, if the blocking end 48 is made shorter. The fastener can be a maximum of about ¾ inch or even ⅝ inch from the driver/plug/knob axis.
The electronic lock of the invention can be in different sizes but in one preferred form the miniaturized electronic cam lock has a length no more than about four inches, a width no more than about one inch, and a depth or thickness no more than about ½ inch excluding the knob or handle. In a lock housing of that size, this is between the fastener 40 (on the right as seen in
Details of the internal actuator mechanism 44 are shown in
As can be seen from the drawings, the bendable coil spring 74 acts as a projecting arm or lever to move the pin 48 out from blocking inwardly or for unblocking. The spring is cantilevered from the side of the actuator arm 76. An inner part 80 of the pin 48, which can be Z-shaped as shown, is slidable within a defined slide channel 82. The spring 74 extends through an opening in the part 80 as shown in
Note that the coil spring 74, which actually acts as a leaf spring, could be replaced by a leaf spring, i.e. a flat metal spring (not shown) that tends toward a predetermined configuration (such as straight) but which will bendably yield to a degree as desired. Such a leaf spring would be in the same position as shown for the coil spring 74. In addition,
The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit its scope. Other embodiments and variations to these preferred embodiments will be apparent to those skilled in the art and may be made without departing from the spirit and scope of the invention as defined in the following claims.
