This invention relates to a locking system useful in closing and securely locking the lid on enclosures such as grade level boxes.
The present locking assembly provides security for enclosures such as grade level boxes used to contain cable TV equipment, data transmission lines, telephone switching equipment, service lines, power transmission devices, and water meters, for example. The invention also has application to other types of ground level enclosures and similar enclosures generally. A significant aspect of the invention is that the locking assembly is self-latching when the lid for the enclosure is simply placed atop the enclosure and forced downwardly to a locked position by applying foot pressure only to the top of the lid. Hence, any need for special tools to lock the lid is avoided.
Briefly, one embodiment of the invention comprises a self-latching locking assembly for locking a lid to the top of a hollow enclosure. The locking assembly includes a spring-biased latch that engages a locking surface on the interior of the enclosure. The locking surface can be a rim or wall section of the enclosure or a recess formed in an inside wall of the enclosure. The locking assembly may be positioned on and adjacent to an edge of the lid. The locking assembly cooperates with the locking surface inside the lid to lock the lid to the top of the enclosure when the lid is placed over the enclosure and the latch is actuated by a downward force, such as foot pressure, for example, against the top of the lid.
One embodiment of the invention comprises a self-latching locking assembly positioned on an edge of a lid that removably mounts over an enclosure. The assembly includes an opening in an upper face of the lid which leads into a slotted housing on the underside of the lid. An L-bolt extends through the opening and into a passage in the slotted housing. A right-angle leg on the L-bolt protrudes below the bottom of the slotted housing. The L-bolt is rotatable by a tool that engages the L-bolt from outside the lid. A separate locking piece positioned inside the passage in the slotted housing retains the L-bolt in the slotted housing and prevents its removal from access outside the lid. The right-angle leg of the L-bolt engages a spring-biased self-latching slide member on the underside of the lid. The slide member is contained in a guide frame structure affixed to the underside of the lid adjacent the slotted housing that contains the L-bolt. The guide frame structure guides spring-biased axial travel of the slide member, which travels axially in the guide frame in unison with rotation of the L-bolt in the slotted housing. A latch carried on the slide member engages a lip or other abutment inside the enclosure when the lid is forced down over the opening in the enclosure. The latch retracts against the spring-bias as it travels over the lip or abutment and then snaps into engagement with a locking surface, such as a notch positioned on the inside of the enclosure below the lip. The latch retracts under the bias of the spring, and the spring force then causes the latch to snap into engagement with the locking surface as the latch travels past the lip or abutment inside the enclosure. This rotates the L-bolt to a spring-biased locked position. Rotation of the L-bolt in a direction away from the locked position retracts the slide member against the spring-bias. The L-bolt can be accessed from outside the enclosure, via a proprietary socket wrench or the like, to rotate the L-bolt away from the locked position, retracting the latch against the bias of the spring, to allow removal of the lid.
Thus, the lid can be positioned over an opening in the enclosure, followed by simply applying downward force, such as foot pressure, for example, to automatically lock the lid in a secure, closed position, without using any tools for locking the lid.
These and other aspects of the invention will be more fully understood by referring to the following detailed description and the accompanying drawings.
The locking assembly is secured to a side portion of the lid so the latch portion of the locking assembly can engage a locking surface on an inside wall of the enclosure. The lid is preferably made from a hard molded plastic material; and in one embodiment, the lid is adapted for closing and locking enclosures such as a grade level box used to contain cable TV equipment, data transmission lines, telephone switching equipment, and other similar service lines, for example. The underside of the lid contains a plurality of spaced apart, parallel ribs 24 that project downwardly into the interior of the grade level box or other enclosure when the lid is in a closed position. The parallel ribs run at right angles to form a grid structure, and the locking assembly can be secured to certain downwardly facing ribs adjacent an edge of the lid.
The locking assembly includes an elongated guide frame 26 affixed to the underside of the lid by fasteners 28. The guide frame details are best shown in
The open space within the guide frame contains a slide member 40 adapted for spring-biased axial travel inside the guide frame. The slide member details are best shown in
The slide member 40 is divided into three sections:
(1) A front section includes a tapered latch 42 which travels axially toward or away from a locking position, in response to axial extension or retraction of the slide member inside the guide frame. The latch is carried on, or integrally formed with, a front portion of the slide member 40.
(2) A rear section includes an upwardly opening generally U-shaped channel 45 which contains a spring member 44. The channel is formed by narrow parallel side walls 46 that slide against the side rails 34 on opposite sides of the guide frame. The slide member is generally T-shaped in cross-section and is configured so a flat base 47 of the slide member (see
(3) An intermediate section includes a connection to an L-bolt 52 that rotates in unison with axial travel of the slide member 40. In the illustrated embodiment, the slide member's L-bolt connection comprises an opening 54 formed in the slide member so as to face laterally outwardly for contact with a right-angle leg 56 of the L-bolt. (The L-bolt is described in more detail below.) The opening 54 is positioned adjacent an angular face 58 formed on the intermediate section of the slide member between the spring-containing channel 45 on the rear section and the latch 42 on the front section of the slide member. The right-angle leg 56 of the L-bolt fits loosely within the opening 54. In use, rotation of the L-bolt can rotate the right-angle leg against the angular face 58 to push the slide member toward a retracted position against the bias of the spring member 44. When the spring tension is released, the slide member slides forward to the locking position. The right angle leg of the L-bolt rotates in unison with the slide member's forward motion. A projection 59 on the guide frame is contacted by the leg portion of the L-bolt to stop forward travel of the slide member.
The spring member 44 is positioned in the channel 45 within the slide member 40. In the illustrated embodiment, the spring member comprises of coil spring, although other means of applying axial spring force the end of the slide member can be used. The coil spring is positioned on an elongated metal rod 60 that extends axially through the center of the channel. A front portion of the rod is affixed to an intermediate portion of the slide member at the front of the channel. A rear portion of the rod passes through an opening in the rear wall 50 of the guide frame. The rod extends along the center of the coil spring to align the coil spring axially within the channel. Retraction of the slide member within the guide frame causes the alignment rod to project out from the rear wall of the guide frame, as shown in
Referring to
In the latched position shown in
Thus, the slide member is engaged in its locked position when the lid is forced down over the opening enclosure, such as by foot pressure. Downward force on the lid progressively causes the latch to retract the spring-bias from contact with the abutment and then snaps the latch into the spring-biased locking position. The L-bolt can be accessed from outside the lid, rotated by the socket wrench or similar proprietary tool, to retract the latch from its locking position sufficiently for removing the lid from the enclosure.
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