Ligature-resistant cover for securing wall-mounted devices

A ligature-resistant thermostat cover provides restriction of access to a thermostat and prevention of ligature formation around or atop the thermostat. The thermostat cover includes a wall plate for securing to a wall with a central aperture for accommodating a thermostat, a cover portion and a locking mechanism. The cover portion is curved both toward the top and toward the bottom of the cover from an apex line to provide a continuously curving front surface of the cover portion. The rear profile of the cover portion matches a mating surface of a front profile of the wall plate in width and height and the wall plate has an incline or curvature at the top face to provide a continuously sloping surface that prevents formation of a ligature point above the top face.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to locking covers for thermostats and other wall-mounted devices, and in particular, to a device cover around which a ligature does not anchor.

2. Description of the Related Art

Ligature-resistant design is a requirement in many institutional locations. In particular, in rooms where persons may be left unattended and where there is a risk that fixtures may be used as a support to tie a ligature, such as a belt, rope or a cloth, a way to ensure that the fixtures cannot be used in such a manner is desirable. In general, ligature-resistant design is an issue that exists any height above the floor, since objects above the floor can be used to support a ligature, even if one is not attachable.

Thermostat covers having locking features are in common-use in public places and private facilities such as hospitals, mental health facilities and incarceration facilities. In such private facilities it is desirable to secure the thermostat against unauthorized access, as in public facilities. Commercial thermostat covers are not suitable ligature-resistant designs and typically provide an upper surface around which a ligature can be attached, vents through which a ligature may be looped and a connection between the wall and the cover into which a ligature may be inserted.

Therefore, it would be desirable to provide a thermostat cover that prevents ligature formation and/or support of such ligatures.

SUMMARY OF THE INVENTION

The above objectives, among others, are achieved in a ligature-resistant device cover and a method of controlling access to a wall-mounted device.

The ligature-resistant device cover includes a wall plate for securing to a wall and with a central aperture for accommodating a thermostat or other device mounted on the wall inside or under the aperture. The ligature-resistant device cover further includes a cover portion that has a first curvature extending along the front from a bottom of the cover portion to an apex line and a second curvature extending along the front from a top of the cover portion and extending to the apex line so that the first curvature and the second curvature provide a continuously curving front surface of the cover portion. The rear profile of the cover portion has a mating surface that matches a mating surface provided on the front profile of the wall plate in width and height. The cover portion has a third curvature at a top face thereof that provides a continuously sloping surface preventing support of a ligature by the top face of the wall plate or a junction between the cover portion and the wall plate. The ligature-resistant device cover also includes a locking mechanism provided on the cover portion for securing the cover portion to the wall plate.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENT

The present disclosure illustrates thermostat covers that provide ligature-resistant structure and installation. The ligature-resistant thermostat covers have a wall plate for securing to a wall and with a central aperture for accommodating a thermostat or other wall-mounted device mounted inside or under the aperture. The ligature-resistant thermostat cover further includes a cover portion that has a first curvature extending along the front from a bottom of the cover portion to an apex line and a second curvature extending along the front from a top of the cover portion and extending to the apex line so that the first curvature and the second curvature provide a continuously curving front surface of the cover portion. The rear profile of the cover portion has a mating surface that matches a mating surface on a front profile of the wall plate in width and height and has a third curvature at a top face thereof matching the first curvature, so that when the cover portion is secured to the wall plate, the wall plate and the cover portion provide a first continuously curved surface above the apex line and extending from the apex line to the wall. The bottom face of the wall plate may be similarly curved, and the sides of the cover portion may also be inclined or curved to meet the apex line. The ligature-resistant thermostat cover also includes a locking mechanism provided on the cover portion for securing the cover portion to the wall plate. The illustrated example is a molded plastic assembly in which the cover is formed from transparent or semi-transparent materials, although the invention is not limited as to materials or techniques of fabrication and opaque materials may be desirable in some applications where it is desirable not to allow visibility of wall mounted devices behind the cover.

Referring now toFIG. 1, a perspective view of an installation of an example ligature-resistant thermostat cover10is shown. Example ligature-resistant thermostat cover10includes a cover portion14that secures to a wall plate12that mounts ligature-resistant thermostat cover10to a wall7. A locking mechanism16locks cover portion14to wall plate12to prevent unauthorized access to a thermostat (not shown) mounted on wall7and to prevent disassembly of ligature-resistant thermostat cover10in a manner that might support formation of a ligature. Cover portion14in the example is a transparent molded plastic piece, although the method of manufacturing and selection of material is not a limitation of the invention, except as specified in the Claims. Cover portion14has a first curvature that extends downward from wall plate12at a top face of cover portion14and terminates at an apex line6below which a second curvature extends downward to the bottom face of cover portion14from apex line6, which may be a complementary curvature to the first curvature as shown. The sides of cover portion14are inclined inward until a radius is reached that extends from the ends of apex line6to the inclined sides of cover portion14. Referring additionally toFIG. 12, inward inclination angle α, which is 15 degrees in the example, is shown. Wall plate12has side, top, and bottom faces that are inclined or curved as needed to provide a relatively smooth transition from the curvatures and inclines of the surfaces of cover portion14outward to wall7, to prevent suspension of a ligature from wall plate12or the transition between wall plate12and cover portion14.FIG. 12shows an inclination angle γ along the left side of wall plate12, which is 30 degrees in the example. Referring additionally toFIG. 11, an inclination angle β of the top and bottom edges of wall plate is shown, which is 35 degrees in the example.

Referring now toFIG. 2, an exploded perspective view of example ligature-resistant thermostat cover10is shown with cover portion14removed to reveal the location of a thermostat3mounted within a central void of wall plate12. A front profile21of wall plate12provides a mating surface that matches a rear profile24of cover portion14in width and height so that cover portion14is snug to wall plate12when cover portion14is secured. Front profile21of wall plate12also includes a pair of ridges23that protrude outward from the top and bottom edges of wall plate12and extend around the corner radii to the sides of wall plate12around front profile21, to prevent insertion of a ligature at the top or bottom of ligature-resistant thermostat cover10between wall plate12and cover portion14. A set of mating features in the form of hooks20are provided at the back bottom and top edges of cover portion and, when cover portion14is installed, engage with a matching set of mating features in the form of recesses22provided through the front face of wall plate12along the top and bottom of the front face of wall plate12. Recesses22have a rectangular profile, as does the lateral profile of hooks20and have two different heights. The greater height portion of recesses22, seen at the leftmost end of recesses22, permits easy insertion of hooks20.The lower height portion of recesses22, seen at the rightmost end of recesses22, secures hooks20over the lower profile portion of recesses22to hold cover portion14in place once cover portion14has been placed with hooks20inserted within corresponding recesses22and then slid to the right, which secures hooks20over the bottom edge of the lower height profile portion of recesses22and also engages locking mechanism16, as will be described in further detail below.

Referring now toFIG. 3AandFIG. 3B, further details of hooks20in cover portion14as illustrated in the right side view ofFIG. 3Aand recesses22in wall plate12as illustrated in the front view ofFIG. 3Bare shown. Hooks20, as seen in detail30A, have an open side facing downward, so that hooks20can be inserted in a larger width portion22A of recesses22as seen in detail30B and suspended by the bottom edge of recesses22to suspend cover portion14in place before sliding cover portion14to the right to secure hooks in a narrower width portion22B of recesses22and engage locking mechanism16, which has a keylock16A portion and is secured to wall plate12by a backplate16B portion of locking mechanism16formed in wall plate12.

Referring now toFIG. 4, further details of cover portion14are shown. Along the right and left sides of rear profile24of cover portion14a vent pattern41is formed in cover portion14that has a plurality of z-shaped channels42that provide blind passages for air circulation, as shown in detail callout40. Z-shaped channels42are sufficiently long in the direction of the height of cover portion14that a ligature-forming element, such as a piece of dental floss, or even a stiff wire cannot be inserted into a first one of z-shaped channels42to emerge in another one of z-shaped channels42, due to the bending of the ligature-forming element that would be required to pass through the first one of the z-shaped channels42. However, air can pass freely through z-shaped channels42, providing ventilation for thermostat3(not shown) both for heat dissipation and to provide an accurate temperature reading of the room air.

Referring now toFIG. 5AandFIG. 5B, details of locking mechanism16formed by keylock16A and backplate portion16B are shown. Keylock16A includes a lock chamber45that is secured through a circular aperture in cover portion14by a nut43and a locking tab47is secured to the interior end of keylock16A by a bolt44. Rotation of a key inserted in keylock16A rotates locking tab47so that in the locked position, locking tab47faces the rear of cover portion14. Locking tab47engages with an aperture46formed in a lock plate48secured within cover portion14, and lock plate44is made from a flexible material such as a thin spring steel sheet, so that keylock16A can be secured prior to installation of cover portion14on wall plate12. When cover portion14is slid rightwards while hooks20are disposed within recesses22, locking tab47will flex lock plate48until locking tab48slides into aperture46with an audible “click” that indicates that cover portion14is secured and locked.

FIG. 6throughFIG. 13depict design features of example ligature-resistant thermostat cover10, in whichFIG. 6is a lower right exploded perspective view,FIG. 7is an upper left exploded perspective view,FIG. 8is a front view,FIG. 9is a rear view,FIG. 10is a right side view,FIG. 11is a left side view,FIG. 12is a top view andFIG. 13is a bottom view illustrating design features of the above-described example ligature-resistant thermostat cover10.