Patent Publication Number: US-6339944-B1

Title: Locking mechanism for trash can receptacle and other doors

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a locking mechanism for trash can receptacles and other like doors. More specifically, the invention relates to a locking mechanism that is mechanically simple, so as to have few moving parts subject to breakage, and is also vandal-resistant. 
     2. Related Art 
     For esthetic reasons, trash cans intended for outdoor use are often put in decorative receptacles. These receptacles are provided with doors, so that the trash cans can be removed for emptying and then replaced. In order to prevent theft of the trash cans from the receptacles, the doors are provided with locking mechanisms. However, in a conventional locking mechanism such common sliding bolt, in which a bolt extends outwardly from the door, if the door is accidentally closed while the bolt is in the locked position, the bolt may be damaged on impact with the body of the receptacle, rendering the locking mechanism inoperative. Also, if the door hinges become misaligned, most conventional locking mechanisms will become inoperative due to misalignment between the bolt and the catch, hasp, or strike plate. Further, in most locking mechanisms of the type used in trash can receptacles, the locking mechanism is not protected against vandalism. It is to the solution of these and other problems that the present invention is directed. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of the invention to provide a locking mechanism for doors that will not be damaged if the door is accidentally shut when the mechanism is in the locked position. 
     In is another object of the invention to provide a locking mechanism for doors that will remain operative even if the hinges become misaligned. 
     It is still another object of the invention to provide a locking mechanism for doors that is vandal resistant. 
     It is still another object of the invention to provide a locking mechanism in which some parts of the mechanism can be replaced if vandalized or otherwise damaged. 
     These and other objects of the invention are achieved by provision of a locking mechanism having a locked and an unlocked condition, comprising a housing assembly and a pin assembly movable relative to each other between open and closed positions. The housing assembly includes a housing, a flapper plate pivotably mounted in the housing, and a cylinder lock mounted in the housing. 
     The housing has closed interior and exterior faces, closed top and bottom faces, an open side face facing the pin assembly, and a closed side face opposite the open side face. The flapper plate is pivotably mounted on a horizontal axis between the interior and exterior faces of the housing, and has a length whereby it can be pivoted upwards to bring its free edge toward the closed side face without contacting the closed side face. 
     The lock is mounted in the exterior face of the housing. It includes a keyway for receiving a key on the exterior of the housing and a finger in the interior of the housing, the finger being rotatable with rotation of the key. 
     The pin assembly includes a faceplate portion configured to cover at least a portion of the open side face of the housing, and a pin extending substantially perpendicularly from the faceplate portion towards the interior of the housing and positioned so as to extend into the interior of the housing and contact the flapper plate with the hook engaging the free end of the flapper plate when the housing assembly and the pin assembly are in the closed position. 
     The finger has a length sufficient to engage the flapper plate and pivot it into a position in which the free edge of the flapper plate is raised above the hook of the pin assembly when the rotor is rotated to bring the finger into a vertical position. The lock is positioned relative to the open side face of the housing such that the finger does not extend beyond the open side face when the finger is in a horizontal position. 
     In one aspect of the invention, the housing assembly further comprises a horizontal shaft rotatably mounted between the interior and exterior faces, wherein the flapper plate extends from the shaft. 
     In another aspect of the invention, the flapper plate has a width slightly less than the interior width of the housing and a length whereby it can be pivoted horizontally toward the closed side face without contacting the closed side face. 
     In still another aspect of the invention, the locking mechanism further comprises a rotor extending into the interior of the housing, the rotor being rotatable in response to rotation of a key inserted into the keyway, and wherein the finger is mounted to the free end of the rotor for rotation with the rotor. Alternatively, a latch can be used instead of a keyed lock; and the finger can be normally biased in the horizontal position so that the pin will lock behind the flapper plate when the door is closed, and turning the latch will rotate the finger into the vertical position to release the pin from the flapper plate. 
     In still another aspect of the invention, the interior face, the top and bottom face, and the closed side face are all formed from a single piece of material, and the exterior face is formed separately and is removably attached to the top and bottom faces and the closed side face. In this aspect of the invention, the edges of the top and bottom faces and the closed side face adjacent the exterior face preferably are provided with lips to which the exterior face can be joined. 
     Other objects, features and advantages of the present invention will be apparent to those skilled in the art upon a reading of this specification including the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is better understood by reading the following Detailed Description of the Preferred Embodiments with reference to the accompanying drawing figures, in which like reference numerals refer to like elements throughout, and in which: 
     FIG. 1 is a partial perspective view of a trash can receptacle having a locking mechanism in accordance with the invention mounted thereon. 
     FIG. 2 is a top plan diagrammatic view of the trash can receptacle of FIG.  1 . 
     FIG. 3 is a side elevational view of the housing assembly and the pin of the pin assembly, with the lock in the locked position and the elements positioned as when the door is partially closed. 
     FIG. 4 is a side elevational view of the housing assembly and the pin of the pin assembly, with the lock in the locked position and the elements positioned as when the door is fully closed. 
     FIG. 5 is a side elevational view of the housing assembly and the pin of the pin assembly, with the lock in the unlocked position and the elements positioned as when the door is fully closed. 
     FIG. 6 is a cross-sectional view taken along line  6 — 6  of FIG.  3 . 
     FIG. 7 is a cross-sectional view taken along line  7 — 7  of FIG.  4 . 
     FIG. 8 is a cross-sectional view taken along line  8 — 8  of FIG.  5 . 
     FIG. 9 is cross-sectional view showing an alternative embodiment of the locking mechanism in the locked condition. 
     FIG. 10 is a cross-sectional view of the alternative embodiment of FIG. 9, with the locking mechanism in the unlocked condition. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. 
     Referring now to FIGS. 1 and 2, there is shown a trash can receptacle  10  (with its cover removed) incorporating a locking mechanism  12  in accordance with the invention. The trash can receptacle  10  includes a body  14  having an interior surface  20   a , an exterior surface  20   b , and a door frame  22  with a top  22   a , a bottom (not shown), and first and second sides  22   b  and  22   c  defining a door opening  24 . A door  30  is pivotably mounted on one of the sides  22   b  by conventional hinges or bearings  32 . Although the trash can receptacle  10  illustrated in FIGS. 1 and 2 has a circular cross-section, it will be appreciated by those of skill in the art that the trash can receptacle  10  can have other configurations, such as a rectangular cross-section, and still incorporate the locking mechanism  12  in accordance with the present invention, as long as the arc of travel of the door  30  is adequate, as described in greater detail hereinafter. Also, it will be appreciated that the locking mechanism  12  can be incorporated into other structures having a door pivotably mounted in a door opening. 
     The locking mechanism  12  comprises a housing assembly  40  and a pin assembly  42  that are movable relative to each other. Preferably, the housing assembly  40  is mounted on a movable object, in the case of FIG. 1, the unhinged side of the door  30 ; and the pin assembly  42  is mounted on a fixed object, in the case of FIG. 1, the door frame side  22   c  facing the unhinged side of the door  30 , opposite the housing assembly  40 . 
     Referring now to FIGS. 3-8, the housing assembly  40  includes a housing  50  having closed interior and exterior faces  50   a  and  50   b , closed top and bottom faces  50   c  and  50   d , an open side face  50   e  substantially aligned with the unhinged side of the door  30 , and a closed side face  50   f  opposite the open side face  50   e . The housing assembly  40  is mounted with the exterior face  50   b  accessible from the interior surface of the door  30 , while the remainder of the housing  50  extends into the interior of the trash can receptacle  10 . Preferably, although not necessarily, the exterior face  50   b  is flush with the exterior surface of the door. Alternatively, for example, the exterior face  50   b  can be inset from the exterior surface of the door. Also, although the housing assembly  40  is shown as being positioned at the top of the door  30 , it can be located further down the unhinged side of the door  30 . 
     Preferably, the interior face  50   a , the top and bottom faces  50   c  and  50   d , and the closed side face  50   f  are all formed from a single piece of material, while the exterior face  50   b  is formed separately and attached to the top and bottom faces  50   c  and  50   d  and the closed side face  50   f  by removable fasteners  52  such as screws, for a purpose to be described hereinafter. To this end, the edges of the top and bottom faces  50   c  and  50   d  and the closed side face  50   f  adjacent the exterior face are provided with lips  54  to which the exterior face  50   b  can be joined. The housing  50  is removably mounted to the trash can receptacle  10  by fasteners (not shown), preferably rivets. Alternatively, the housing  50  also can be mounted to the trash can receptacle  10  by other fastening means, such as bolts or by tack-welding. 
     Opposed apertures  62  are formed in the  50   a  and  50   b  inset inwardly from the open side face  50   e  and downwardly from the top face  50   c . These apertures  62  are fitted with bushings  64 , and a horizontal shaft  66  is rotatably mounted in the bushings  64 . A flapper plate  70  extends from the shaft  66 . The flapper plate  70  can be unitarily formed with the shaft  66 , or formed as a separate piece welded to the shaft  66 . As best shown in FIGS. 3,  4 , and  7 , the flapper plate  70  has a width slightly less than the interior width of the housing  50  and a length less than the distance between the shaft  66  and the closed side face  50   f , so that the flapper plate  70  can be pivoted toward the closed side face  50   f  without contacting the closed side face  50   f . Preferably, the housing  50 , the shaft  66 , and the flapper plate  70  are all made of stainless steel. 
     The flapper plate  70  has exterior and interior faces  70   a  and  70   b  that respectively face the exterior and the interior of the housing  50  when the flapper plate  70  is hanging freely, and a free edge  70   c  opposite the shaft  66 . If the flapper plate  70  or the shaft  66  requires replacement, the flapper plate  70  and shaft  66  can be removed from the housing  50  by removing the exterior face of the housing  50 . 
     As best shown in FIGS.  2  and  6 - 8 , the pin assembly  42  comprises a bracket  80  and a pin  82  mounted to the bracket  80 . The bracket  80  in transverse cross-section is substantially L-shaped, with a faceplate portion  84  and a mounting portion  86 . The mounting portion  86  is a generally planar plate that is attached, for example by welding, to the exterior of the trash can receptacle  10 . The faceplate portion  84  also is a generally planar plate, which extends from the mounting portion  86  into the interior of the trash can receptacle  10 , and which is configured to cover at least a portion of the open side face  50   e  of the housing  50  when the door  30  is in the closed position. The pin  82  extends substantially perpendicularly from both sides of the faceplate portion  84 . On one side of the faceplate portion  84 , the pin  82  protrudes into the door  30  opening so as to extend into the interior of the housing  50  immediately below the shaft  66  when the door  30  is in the closed position. On the other side of the faceplate portion  84 , the pin  82  rests against the interior surface  20   a  of the body  14  of the trash can receptacle  10 . The pin  82  is rigid, and is welded to the facing surface of the trash can receptacle  10 . Preferably, the pin  82  and bracket  80  are powder-coated, galvanized steel. 
     As shown in FIGS. 3-8, the pin  82  is cylindrical, with a flattened, downwardly-angled, notch  90   a  formed in the upper surface  90   b  adjacent the free end to define a hook  92  at the free end of the pin  82 . However, it will be appreciated that the pin  82  can have configurations other than cylindrical, and that the hook  92  can be defined other than by a notch  90   a  in the upper pin surface  90   b.    
     The pin assembly  42  is positioned vertically relative to the housing assembly  40  so that the hook  92  will strike the exterior face of the flapper plate  70  above its free edge  70   c  when the flapper plate  70  is hanging freely. As the door  30  is pivoted closed, the hook  92  travels inward towards the closed side face  50   f  of the housing  50  and contacts the exterior face of the flapper plate  70 , causing the flapper plate  70  to pivot upwardly. Because of the arc of travel of the door  30 , and particularly the arc of travel of its unhinged side, the pin  82  approaches the housing  50  in a horizontal plane and first contacts the exterior face  70   a  of the flapper plate  70  just inside the interior face  50   a  of the housing  50 . The width of the flapper plate  70  ensures that the hook  92  will contact the exterior face  70   a  of the flapper plate  70  even though the pin  82  is initially off-center in the horizontal plane relative to the flapper plate  70 . The pin  82  is of such length relative to the flapper plate  70  that when the door  30  is in the fully closed position, with the faceplate portion  84  of the pin assembly  42  positioned opposite the open side face  50   e  of the housing  50 , the hook  92  engages against the free edge  70   c  of the flapper plate  70 , as shown in FIG.  7 . 
     A conventional cylinder lock  100  is mounted in the exterior face of the housing  50  inset upwardly of the bottom face and inwardly of the closed side face  50   f . The cylinder lock  100  has a keyway  102  on the exterior of the housing  50  for receiving a key  106 , and a rotor (not shown) extending into the interior of the housing  50 , the rotor being rotatable in response to rotation of the key  104  in the keyway  102 . A finger  108  is mounted to the free end of the rotor for rotation with the rotor. 
     The finger  108  has a length sufficient to engage the flapper plate  70 , and pivot it into a position in which its free edge  70   c  is raised above the hook  92  when the rotor is rotated to bring the finger  108  into a vertical position, as shown in FIG. 8, for a purpose to be described hereinafter. 
     The cylinder lock  100  is removably retained in the exterior face  50   b  of the housing  50  by, for example, a retaining nut  110 . If the cylinder lock  100  is damaged, the exterior face  50   b  can be detached from the housing  50  and the cylinder lock  100  can be replaced. 
     The cylinder lock  100  has a locked position, in which the pin  82 , once inserted into the housing  50 , cannot be removed; and an unlocked position, in which the pin  82 , if inserted into the housing  50 , can be removed, as will be described in greater detail hereinafter. When the cylinder lock  100  is in the locked position, the finger  108  extends horizontally towards the open side face  50   e  of the housing  50 , allowing the flapper plate  70  to hang freely; and when the cylinder lock  100  is in the unlocked position, the finger  108  extends vertically towards the top face of the housing  50  so that the free edge  70   c  of the flapper plate  70  is raised above the hook  92 , as shown in FIG.  8 . It will be appreciated that the cylinder lock  100  must be positioned relative to the open side face  50   e  of the housing  50  such that the finger  108  does not extend beyond the open side face  50   e  when the cylinder lock  100  is in the unlocked position. 
     As the door  30  is closed, the pin  82  travels into the interior of the housing  50  and the hook  92  contacts the exterior face of the flapper plate  70 , causing the flapper plate  70  to pivot upwardly. As the pin  82  travels farther into the interior of the housing  50 , the hook  92  moves towards the free edge  70   c  of the flapper plate  70 . When the hook  92  clears the free edge  70   c  of the flapper plate  70 , gravity causes the flapper plate  70  to drop into contact with the upper surface of the pin  82 , locking the hook  92  between the free edge  70   c  of the flapper plate  70  and the back face of the housing  50 . The pin  82  cannot be withdrawn from the housing  50  until the hook  92  is freed from the flapper plate  70 . To this end, the cylinder lock  100  can be moved into the unlocked position. 
     As the key  104  is rotated into the unlocked position, the rotor also rotates, and with it, the finger  108 , which rotates from a horizontal to a vertical position. As the finger  108  rotates upwardly towards the vertical, it contacts the exterior face of the flapper plate  70  and causes it to rotate upwards to a position in which the free edge  70   c  of the flapper plate  70  clears the hook  92 . Because of this arrangement, if the door  30  is accidentally closed when the cylinder lock  100  is in the locked position, the pin  82  will simply engage and lock behind the flapper plate  70  without damage to either the pin assembly  42  or the housing assembly  40 . 
     Alternatively, as shown in FIGS. 9 and 10, a latch  100 ′ can be used instead of the keyed cylinder lock  100 . The latch  100 ′ is constructed similar to the cylinder lock  100 , except that a rotatable handle  104 ′ replaces the key  104  and the keyway  102 ; and the finger  108  is normally biased in the horizontal position, for example by a tension spring  120  attached at one end to one face of the flapper plate  70  and at the other end to the bottom face  50   d , so that the flapper plate  70  normally hangs freely and the pin  82  will lock behind the flapper plate  70  when the door  30  is closed. As will be appreciated by those of skill in the art, an appropriately positioned compression spring can be used in place of the tension spring  120 . Turning the latch handle  104 ′ causes rotation of the rotor and the finger  108  in the same manner as in the cylinder lock  100 . Because the finger  108  is normally horizontal, turning the handle  104 ′ will rotate the finger  108  into the vertical position to pivot the flapper plate  70  upward and release the pin  82  from the flapper plate  70 . 
     It is noted that the faceplate portion  84  need not abut the open side face  50   e  of the housing  50  when the door  30  in the fully closed position. A gap can be present between the faceplate portion  84  and the open side face  50   e  of the housing  50 , as long as the gap is small enough to prevent picking of the cylinder lock  100  therethrough. Similarly, the faceplate portion  84  need not cover the entire open side face  50   e  of the housing  50 , as long as it covers enough of the open side face  50   e  to prevent picking of the cylinder lock  100 . The gap between the faceplate portion  84  and the housing  50  is beneficial, in that it permits some play between the different parts of the locking mechanism  12  if the door  30  becomes misaligned. 
     It will be appreciated that the lock  100  must be positioned relative to the open side face  50   e  of the housing  50  such that the finger  108  does not extend beyond the open side face  50   e ; otherwise, the finger  108  would the faceplate portion  84  from seating properly opposite the open side face  50   e.    
     The pin  82  and the finger  108  are positioned relative to each other such that the finger  108  does not interfere with travel of the pin  82  into the housing  50 . In the embodiment as illustrated in FIGS. 3-5, this is achieved by offsetting the finger  108  to towards the exterior face  50   b  of the housing  50 , while positioning the finger  108  so that it substantially centered between the interior and exterior faces  50   a  and  50   b.    
     As long as the finger  108  is disengaged from the flapper plate  70 , the flapper plate  70  is free to pivot, so that when the door  30  is closed, gravity will cause the free edge  70   c  to rest against the notch  90   a  and lock behind the hook  92 . The hook  92  cannot disengage from behind the free end of the flapper plate  70 , effectively locking the door  30  in the closed position. However, if the cylinder lock  100  is turned so that the finger  108  is in the vertical position, the free edge  70   c  of the flapper plate  70  is raised above the hook  92 , effectively unlocking pin  82  and allowing the door  30  to be opened. Furthermore, because the faceplate portion  84  covers the open side face  50   e  of the housing  50  when the door  30  is in the closed position, the locking mechanism is vandal resistant. 
     An advantage of the construction of the locking mechanism  12  is that it will not be damaged even if the door  30  is closed when the key  104  is turned to the locked position. This is because, as previously pointed out, the flapper plate  70  is free to rotate when the cylinder lock  100  is in the locked position. 
     In a trash can receptacle  10  of the type illustrated in FIG. 1, the hinges  32  are located so that the door  30  will swing along an arc that brings the open side face  50   e  of the housing  50  towards the pin  82  at an angle, thus allowing the pin  82  to clear the interior face of the housing  50  yet still engage the flapper plate  70  in the interior of the housing  50 . It will be appreciated that the locking mechanism  12  in accordance with the invention can also be used with a sliding door. In that case, the pin  82  would enter the interior of the housing  50  head-on. 
     Modifications and variations of the above-described embodiments of the present invention are possible, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described.