Abstract:
A mail collection point-of-use for and method of preventing detected hazardous materials within a mail collection point-of-use from contaminating components of subsequent mail delivery system processes. The mail collection point-of-use comprises a mail drop unit having an opening for receiving customer-deposited mail, a mail receptacle for accumulating received mail, an enclosure coupled to the mail drop unit and containing the mail receptacle and having a door that seals an opening large enough to permit removal of the mail receptacle, a detector inside the enclosure, which generates a detection signal upon detection of airborne hazardous material, and an indicator outside the enclosure for indicating the detection of hazardous material. By indicating the detection of hazardous materials within the mail collection point-of-use before removing the mail receptacle and its contaminated mail, the further spread of the hazardous materials in a mail delivery system may be prevented.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   Priority under 35 U.S.C. § 119 is claimed based on U.S. Provisional Application No. 60/420,980, filed on Oct. 24, 2002 the disclosure of which is expressly incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Technical Field 
   Embodiments disclosed herein relate to a mail collection point-of-use for reducing the spread of hazardous materials deposited in a mail collection point-of-use to processing equipment in a mail delivery system. In particular, they relate to a mail receptacle which reduces the force of impact experienced by deposited mail, and a mail collection point-of-use which provides an indication of the detection of hazardous materials within it, prior to the removal from the point-of-use of a mail receptacle and its contaminated mail. 
   2. Description of Related Art 
   Standard postal points-of-use include the familiar curbside mail collection boxes. They also include the PS 1814 face plate drop unit and 1577 letter drop units in the wall of a lobby of a post office or other building. Points-of-use installed in the wall have corresponding mail receptacles on the opposite side of the wall in a workroom, where the process of mail delivery begins with sortation. A curbside mail collection point-of-use has a mail receptacle within it. 
   Mail deposited into a postal point-of-use slides and falls from the point of deposit to a landing place, which, in an empty mail receptacle, is the bottom of the mail receptacle. The bottom of the mail receptacle is approximately a meter below the point of deposit. The force of impact with which the mail hits the bottom of the mail receptacle can cause any powdery substance within the mail to escape through openings or porous surfaces into the air. Moreover, as additional mail is deposited on top of the deposited contaminated mail, the contaminated mail becomes compressed, which can force more powdery hazardous material into the air. 
   In mail receptacles accumulating mail from building lobbies, the mail receptacle has an open top. Thus the air in and near the mail receptacle is not isolated from the rest of the work area containing the mail receptacle. With all types of mail collection points-of-use, a mail handling employee regularly checks to see when the mail receptacle is full. The employee removes the full mail receptacle and places an empty one in its place to accumulate newly deposited mail by customers. The full mail receptacle is taken to the next mail delivery processing equipment. During that subsequent mail processing step of sorting, the pieces of mail are compressed further, enabling any powdery hazardous material contained in the mail to escape the mail through openings or porous surfaces and contaminate the surrounding air and equipment. Contamination of the air and equipment places mail handling employees at risk of exposure to hazardous materials. There is a need to prevent contamination of the air in the work area and the spread of hazardous materials to further mail processing equipment. 
   Events of 2001 involving anthrax pointed out the need for early detection of hazardous materials in mail or otherwise placed in the mail delivery system for health and successful investigation of the perpetrators, and preferably prior to the mail reaching automated equipment which spread the anthrax within the postal service work areas. 
   SUMMARY 
   As embodied and broadly described herein, an embodiment consistent with the invention is a mail collection point-of-use comprising a mail drop unit having an opening for receiving customer-deposited mail and an enclosure coupled to the mail drop unit. The enclosure has an opening and a door sealing the opening when the door is closed. The mail collection point-of-use also comprises a mail receptacle inside the enclosure for accumulating received customer-deposited mail. The receptacle and the enclosure&#39;s opening are sized to permit removal of the receptacle from the enclosure through the opening. A detector positioned inside the enclosure generates a detection signal upon detection of airborne hazardous material. The mail collection point-of-use also has an indicator positioned outside the enclosure, which is coupled to the detector and generates an indication upon receipt of the detection signal. 
   Another embodiment consistent with the invention is a method of preventing detected hazardous materials within a mail collection point-of-use from contaminating components of subsequent mail delivery system processes. The method comprises receiving customer-deposited mail through an opening in a mail drop unit, accumulating received customer-deposited mail in a mail receptacle contained in an enclosure, and examining air within the enclosure for airborne hazardous material. If hazardous material is detected, the method includes generating a detection signal and indicating the detection of hazardous material. 
   It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments consistent with the invention and together with the description, serve to explain the principles of the invention. In the drawings, 
       FIG. 1  is a section view of a mail collection point-of-use consistent with the invention taken along line  1 — 1  of  FIG. 2 ; 
       FIG. 2  is a rear view of the mail collection point-of-use of  FIG. 1 ; 
       FIG. 3  is a partial rear view of a mail collection point-of-use consistent with the invention having an empty sack and two parallel brackets with hooks engaging grommets in the sack and four springs elevating a platform supporting the bottom of the sack; 
       FIG. 4  is a partial side view of the mail collection point-of-use of  FIG. 3  as seen on line  4 — 4  of  FIG. 3 ; 
       FIG. 5  is a rear view of the sack filled with accumulated mail with four bungee cords attached to the brackets and a platform and stretched a distance proportional to the weight of mail accumulated in the sack; and 
       FIG. 6  is a perspective view of the sack of  FIG. 5  when the sack is empty and the bungee cords have elevated the platform. 
       FIG. 7  is a section view of a stand-alone mail collection point-of-use consistent with the invention. 
       FIG. 8  is a section view of mail collection point-of-use consistent with the invention with a modified 1577 letter drop unit. 
       FIG. 9  is a section view of a PS 1814 series face plate drop unit. 
       FIG. 10  is a front view of a curbside mail collection point-of-use. 
       FIG. 11  is a side view of the curbside mail collection point-of-use in  FIG. 10 . 
   

   DESCRIPTION OF EMBODIMENTS 
   Reference will now be made in detail to the exemplary embodiments consistent with the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
   As shown in  FIGS. 1 and 2 , a mail collection point-of-use  200  includes a mail drop unit  20  with a front wall  23  and an opening  27  for receiving customer-deposited mail from a customer accessible area  11 , for instance, the public lobby of a United States Post Office or other building. Opening  27  is of an appropriate size and shape to accommodate commonly deposited mail or bundles of mail. Mounted by screws onto front wall  23  in  FIG. 1  is a face plate drop unit  28 , preferably of a PS 1814 series type, (see  FIG. 9 ), which defines opening  27 . 
   Mail drop unit  20  has a top wall  22 , side walls  25 , and a bottom wall  24  that match in size and shape the surrounding surfaces of a wall  10 , which separates customer-accessible area  11  from a non-customer-accessible work area  13 . As illustrated in  FIG. 1 , a chute  21 , is provided for guiding received mail from opening  27  to a rigid, constant-volume container  31  form of a mail receptacle. 
   As illustrated, container  31  has a bottom wall  35 , four side walls  36  that form internal angles greater than ninety degrees with bottom wall  35 , and an open top. Container  31  may have any appropriate shape, however. The perimeter of the top of container  31  is positioned to receive deposited mail. Container  31  is shown in  FIG. 1  as partially filled with accumulated mail  100 . 
   An enclosure  40  surrounds container  31 . Enclosure  40  may be made of any material that does not allow air containing hazardous materials to pass. Enclosure  40  has a bottom wall  44 , top wall  45 , back wall  46 , front wall  47 , and two side walls  48 . Front wall  47  is connected to side walls  25 , top wall  22 , and bottom wall  24  of mail drop unit  20 . As seen best in  FIG. 2 , back wall  46  has a sealed door  41  (preferably hermetically sealed) having two hinges  42  and a handle  43 . Door  41  is not required to be on back wall  46 , but could be on either side wall  48  ( FIG. 1 ) or a combination of back wall  46  and a side wall  48 , or even top wall  45 . When closed, door  41  hermetically seals an opening sized to permit removal of container  31  ( FIG. 1 ) when full of accumulated mail  100 . Enclosure  40  also has a flange  49  that is both secured and sealed to wall  10  and or a floor  12  of work area  13  when attached with flat head slotted wood screws. Alternatively, enclosure  40  could be attached to wall  10  or floor  12  by other appropriate means. 
   As illustrated in  FIG. 1 , enclosure  40  contains a detector  70 . Detector  70  examines air within mail collection point-of-use  200  for the presence of hazardous material and generates a detection signal upon detection of airborne hazardous material. Detector  70  is attached on top wall  45  of enclosure  40 . Enclosure  40  also houses an intermittently activated vacuum fan  15  for increasing the rate at which any airborne hazardous material travels to detector  70 . Fan  15  may suck air from container  31 , preferably through a flexible duct or tube, such as flexible duct  16 , and direct air to detector  70 . As illustrated in  FIG. 1 , fan  15  has a switch, such as an AC/DC control switch circuit  71 , wired to detector  70 . Control switch circuit  71  may be selectively and automatically opened upon detecting hazardous material to deactivate fan  15 . Other appropriate means may be used for increasing the rate at which hazardous material reaches detector  70 . 
   Mail collection point-of-use  200  also includes indicators  81  and  82  coupled to detector  70  and which generates an indication upon receipt of the detection signal. Indicators are preferably sources of visible light but could include broadcast public address system voice messages announcing the presence of hazardous material; scrolling messages on display boards; or audio indicators generating sound, either at a constant value or varied in a pattern once the detector has detected the presence of hazardous materials. Sources of visible light may include LEDs; liquid crystal displays; an incandescent, fluorescent, or neon lights. Audio indicators may include buzzers, horns, sirens, or chimes. Text indicators on enclosure  40  may be used in conjunction with the visual or audio indicators to explain the significance of indication. 
   As illustrated in  FIGS. 1 and 2 , indicator  81  is an incandescent bulb for generating visible light and indicator  82  is a buzzer for generating sound upon receipt of the detection signal from detector  70 . Bulb  81  and buzzer  82  are mounted on the outside surface of enclosure  40 . Detector  70  may be hard-wired to buzzer  82  and bulb  81  or coupled by other appropriate means. 
   When detector  70  detects hazardous material, it activates buzzer  82  and bulb  81  and deactivates fan  15 . A mail handling employee seeing the light from light bulb  81  and or hearing the sound from buzzer  82  is trained to realize that hazardous material has been detected within enclosure  40  and can notify a person with authority to safely handle the hazardous material. An investigation can then be conducted, rather than exposing personnel to the hazardous material when they open door  41  to check on the level of accumulated mail  100  in container  31  and remove container  31  and its contaminated mail. A part of that investigation may include removing mail collection point-of-use  200  to a safe location before opening door  41  to remove container  31  and its contaminated mail. Hazardous material detected within enclosure  40  therefore is not spread to processing equipment in a mail delivery system, such as sortation equipment. 
   In other embodiments consistent with the invention, as illustrated in  FIGS. 3–6 , mail collection point-of-use  200  may include a lower positioning structure  59 A ( FIGS. 3–4 ) and  59 B ( FIGS. 5–6 ) for establishing the bottom of the mail receptacle at an initial position below the top of the mail receptacle and for lowering the bottom of the mail receptacle as a function of the weight of the accumulated mail, thereby reducing the distance the deposited mail falls into an empty mail receptacle and the force with which it lands. The reduced falling distance and landing force reduces the amount of any powdery hazardous material contained in deposited mail that is dispersed through openings and porous surfaces in the mail. 
   In a second embodiment consistent with the present invention, as illustrated in  FIGS. 3 and 4 , a mail collection point-of-use  200 A comprises the same elements as in point-of-use  200  ( FIGS. 1–2 ), except that it includes a mail receptacle in the form of a sack  32 , which is an expandable and collapsible container, as illustrated in  FIG. 3 , and not rigid, constant-volume container  31  ( FIGS. 1–2 ). Those elements that are in common between points-of-use  200  and  200 A will not be described again unless necessary. 
   Sack  32  comprises a flexible, expandable, and collapsible container. As illustrated, sack  32  may be made of canvas and has grommets  34  spaced along the top edge. Sack  32  may be formed of other flexible material such as polyester, or any material strong enough to support accumulated mail without tearing. Preferably, it should support 40 pounds and 85 pounds tear weight of accumulated mail. An expandable and collapsible container need not be a sack, but could be of other appropriate construction, such as self-supporting plastic or paper container with horizontally, pre-creased walls that will expand and collapse like an accordion or bellow. 
   Mail collection point-of-use  200 A further comprises an upper positioning structure  55  for maintaining the top of sack  32  in an open position and at a fixed distance below opening  27  of mail drop unit  20 . As illustrated, upper positioning structure  55  comprises two generally parallel brackets  50 , hooks  51 , and grommets  34  in sack  32 . Each bracket  50  has hooks  51  engaging a plurality of grommets  34  spaced along the top edge of sack  32 . Brackets  50  need not be of the shape illustrated, nor mounted on bottom wall  44  of enclosure  40  ( FIG. 1 ), but could be mounted to any wall of enclosure  40  and still perform their function. Brackets  50  could alternatively be replaced by a self-supporting frame that sits on bottom wall  44  of enclosure  40  ( FIG. 1 ). Alternatively, sack  32  need not have grommets  34 , but could have rings such as on a. shower curtain to hang over hooks in brackets  50  or frame, or could have loops formed from the same material as the container. Alternatives to hooks and grommets are standard methods of removably securing flexible material to a frame, such as Velcro, interlocking pieces or clips with the material of the container compressed between them, etc. A requirement of these alternatives is that they must support the design weight of a mail receptacle filled with accumulated mail without detaching from the frame, which in this embodiment is around 70 pounds. 
   Mail collection point-of-use  200 A also has a lower positioning structure  59 A for establishing the bottom of the mail receptacle at an initial position below the top of the mail receptacle when empty and for lowering the bottom of the mail receptacle as a result of the weight of the accumulated mail. As the weight increases, the bottom of the mail receptacle is lowered a proportional distance. As illustrated in  FIGS. 3 and 4 , lower positioning structure  59 A comprises a rectangular, plywood platform  60  for supporting the bottom of sack  32  and four compressible coiled springs  61 . Springs  61  are positioned between platform  60  and bottom wall  44 . Each of the four springs  61  supports platform  60  near a different corner and together springs  61  elevate platform  60  and establish the bottom of sack  32  at a position near bottom edge  26  of chute  21 , but below the top of sack  32  when empty. 
   Alternatively, platform  60  could be made of any material sufficiently strong to support the weight of a mail receptacle full of mail without deforming from the localized pressure exerted by springs  61 . Platform  60  also may be any shape that supports the bottom of a mail receptacle. Finally, a platform is not needed if the bottom of sack  32  includes a reinforcement member to prevent deformation from the localized pressure produced by springs  61 . 
   If desired, a rectangular plywood base (not shown) may be provided between bottom wall  44  of enclosure  40  and the bottom of springs  61  such that springs  61  are then positioned between platform  60  and the rectangular plywood base. The base may be set on or mounted to bottom wall  44 , if desired. 
     FIGS. 5 and 6  show another mail collection point-of-use  200 B, consistent with the invention. Those elements that are the same as mail collection points-of-use  200  and  200 A will not be described again unless necessary. In  FIGS. 5 and 6 , a lower positioning structure  59 B has four resilient cords  62 , such as bungee cords, and platform  60  and establishes the bottom of sack  32  at an initial position below the top of sack  32  and lower the bottom of sack  32  as a function of the weight of the accumulated mail. Each cord  62  is connected to a corner of platform  60  and the corresponding end of bracket  50  above that corner. As sack  32  accumulates received customer-deposited mail, the weight of accumulated mail  100  stretches cords  62  and lowers platform  60 . As the platform  60  lowers, sack  32  expands to accumulate additional, received mail.  FIG. 5  illustrates this embodiment when cords  62  are stretched proportionally to the weight of accumulated mail  100  and have lowered the bottom of sack  32  the distance they (bungee cords  62 ) have stretched. 
   Embodiments consistent with the invention are not limited to springs or resilient cords for establishing the bottom of the mail receptacle at an upper position below the top of the mail receptacle and for lowering it as a function of the weight of the accumulated mail. Any structure that provides a upward force proportional to weight to the bottom of the mail receptacle, either directly or indirectly, may be used, such as air cylinders or hydraulics in conjunction with appropriate controls. 
   As shown in  FIGS. 5 and 6 , platform  60 , as it is raised and lowered, is guided by vertical portions of brackets  50  and by an additional vertical guide  52  positioned on the side of platform  60  closest to front wall  47 . Vertical guide  52  is mounted to bottom wall  44  of enclosure  40  ( FIGS. 1 and 2 ) and may also provide a boundary for sack  32  as it expands. In certain applications, multiple vertical guides, similar to vertical guide  52 , may be added. Vertical guides, like vertical guide  52 , do not need to be mounted to bottom wall  44 , but can be in a shape for mounting to any wall ( 44 ,  45 ,  46 ,  47 , and  48  as shown in  FIGS. 1 and 2 ) of enclosure  40  ( FIGS. 1 and 2 ). A requirement for any vertical guide is to avoid obstructing the removal of mail receptacle, as sack embodiment  32  or otherwise, from enclosure  40  ( FIGS. 1 and 2 ) through door  41  ( FIGS. 1 and 2 ). 
   As illustrated in  FIGS. 3 ,  4 , and  6 , by establishing the bottom of sack  32  when empty to a position closer to bottom edge  26  of chute  21  than bottom wall  44 , mail deposited by a customer through opening  27  falls a shorter distance into an empty mail receptacle and lands with a smaller force. This reduced falling distance and landing force reduces the amount of any hazardous material contained in the deposited mail that is dispersed upon landing through openings and porous surfaces in the mail. 
   In a fourth embodiment consistent with the present invention (not illustrated), a mail collection point-of-use differs from that of the first embodiment in that rigid, constant-volume container  31  is replaced with sack  32  and upper positioning structure  55  as described in mail collection point-of-use  200 A. 
   In a fifth embodiment consistent with the present invention, a mail collection point-of-use  200 C differs from that of mail collection point-of-use  200  in that the area outside enclosure  40  ( FIGS. 1 and 2 ) may be completely a generally customer-accessible area  11 , without wall  10  separating area  11  from non-customer-accessible work area  13 , such that customers may access the area around side walls  48 , top wall  45  and back wall  46  of enclosure  40 . Flange  49  may be bolted to a floor  14  of customer-accessible area  11 . Opening  27  of mail drop unit  20  may be in front wall  47 , as top wall  22 , bottom wall  24  and side walls  25  no longer need to extend through wall  10  ( FIG. 1 ). 
   Illustrated in  FIG. 8  is a sixth embodiment consistent with the present invention: a mail collection point-of-use  200 D has a mail drop unit  20  in the form of a modified 1577 letter drop unit and a mail receptacle  33 . In all other respects, mail collection point-of-use is the same as mail collection point-of-use  200 . Modified 1577 letter drop unit  20  is flush with front wall  47  of enclosure  40 , as wall  10  is trimmed to provide access to opening  27 A of modified 1577 letter drop unit  20 . Letter drop unit  20  may be bolted to brackets, which may be welded to front wall  47 . In letter drop unit  20 , a hinged door, which covers a second opening  27 B, is blocked from rotating about point C and therefore is not used to receive and guide mail. As illustrated in  FIG. 9 , chute  21 B is connected to wall  23  below opening  27 A. Chute  21 C is connected to wall  23  below chute  21 B and is hinged to chute  21 D. Chute  21 D is magnetically attached to top wall  22 , but detaches and rotates about point C when sufficient mail has accumulated to overcome the magnetic force, guiding the mail into container  33 . Specific to modifications of a 1577 letter drop unit, chute  21 D may be removed altogether and chute  21 C extended with piece  21 E.  FIG. 9  illustrates both modification options. In general a chute could also be a conveyor belt, a tube, a duct, a channel, or a hinged flap drop. 
   In a seventh embodiment consistent with the present invention, a mail collection point-of-use, the familiar curbside mailbox, shown in  FIGS. 10 and 11 , may be retrofitted with any of the aforementioned mail receptacles and any necessary positioning structures, a detector  70 , an indicator, fan  15 , and switch  71 , each sized to fit within the enclosure of the mailbox. Detector  70 , indicator  81 , and fan  15  may be powered by any appropriate source, including solar power, or the generation of electricity through the manual rotation of the hinged flap door during opening and closing during the deposit of mail into the mail drop. 
   Other embodiments consistent with the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.