Abstract:
The invention is an improved mailbox in which a sectional roll-up type door, in addition to enhancing the aesthetic appeal, facilitates access to the mail box contents, can be used in a weather-resistant way at the side or rear to avoid standing in traffic, and can also be used as a platform for insulation, solar collection, displays, lighting and various types of sensing of conditions at the interior of the mailbox such as the presence or absence of mail. The sectional door moves along parallel tracks that are mounted in the interior of the box.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to provisional patent application U.S. Ser. No. 61/826,636, filed May 23, 2013 by the same inventor and having the title “Easy opening garage door style mailbox”. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention pertains to improved designs for mailboxes. 
       BACKGROUND 
       [0003]    From 1863 to 1916 most United States mail was delivered in person, requiring the postal carrier to wait for someone to answer the door at each recipient building. To avoid the wait-time burden on carriers, residents were increasingly encouraged to provide a mail slot or more preferably attached mailbox near shoulder height to receive mail in their absence. 
         [0004]    Finally in 1916, U.S. households were required by law to provide a mail slot or attached mailbox to receive mail. Although still in use, these mail receptacles are themselves now disfavored because they require delivery on foot. Thus mail slots and mail boxes attached to walls are primarily found only in older structures due to a regulatory ban in 1978 that forbid their use in subsequently constructed buildings. 
         [0005]    At about the same time that mailbox use became mandatory, the original roadside mailbox—better known as the rural or curbside mailbox—was developed by a postal employee. This became an instant classic and is still the most popular design. This curbside design is named the Joroleman mailbox after its inventor, and has: a rectangular base; raised floor; arching single piece of usually sheet steel defining the top and sides; front door having a hinge at the bottom and latch at the top; and pivoting rigid semaphore flag on one side. This arched design, which is more commonly designated as “dome-rectangular” or “tunnel-top”, is simple to manufacture, facilitates runoff of rain, snow and ice, and has good mechanical strength. 
         [0006]    Since its introduction various innovations have been introduced. For instance a current commercial model has identical front and back doors but otherwise largely resembles the original Joroleman design. Another variation was constructed of transparent material to enable viewing of mail inside. A third variant features a tray on the bottom that slides out so delivered mail will not be left inadvertently at the rear of the box. 
         [0007]    Curbside mailbox designs have evolved and diversified somewhat in the past century. The United States Postal Service (USPS) currently classifies them in three categories. The traditional (“T”) category is the Joroleman type. The contemporary (“C”) category covers alternative designs and began in 1978. Both T and C categories have three approved sizes based on minimum interior measurements; the maximum allowed size is 22.81 inches long, 11 inches wide and 15 inches high (at the peak). The locking (“L”) category refers to boxes that can be locked by the customer; these designs have fewer restrictions on their size and shape, however the postal service does not unlock them but instead delivers the mail into a slot that is at least 10 inches wide by at least 1.75 inches high. The L category slot is at a height of 41 to 45 inches above the ground, with the front of the box being 6 to 8 inches back from the curb. Locking designs are also found in many communal letter box stations, which are becoming more prevalent. A box from any of the T, L or C curbside designs may be affixed to a support beam, and its distance from the road surface may vary by local requirements, depending on the local environment and road conditions. 
         [0008]    The industrial design employed in the Joroleman and other boxes is often deemed elegant both in terms of manufacturing (requiring only simple processes and few piece parts) and utilitarian benefit. However they have disadvantages. In particular, a typical front-opening curbside box requires the user to step into the street to retrieve mail, which commonly requires considerable care at locations where the road has much traffic or a blind curve nearby. 
         [0009]    Curbside boxes also suffer from extreme temperatures, which can damage mailed items such as pharmaceuticals, beauty products, consumer products, etc. For example, a study by the Food and Drug Administration (FDA) determined that when the ambient air temperature is 101° F. (i.e., about 38° C.), full sun shining on the outer surface of a black (consumer) mailbox can generate an interior temperature that is higher still by 35° F. (i.e., about 20° C.). The alternative to ordinary mail for shipping temperature-sensitive products is to employ a private delivery vendor, however this is often more expensive. 
         [0010]    An additional issue is collection of precipitation on the inner surface of a door for a curbside box. The door of the Joroleman box is essentially a flap: when opened to the full position the door is often horizontal and parallel to the ground, in which position it receives whatever rain or snow is falling from the air or sliding off the arched top or the user&#39;s garments. When the flap is dosed, the inside of the box is then exposed to that condensation, which is unlikely to run off or evaporate rapidly. 
         [0011]    Additional disadvantages of curbside mailboxes arise due to their distance from the building(s) at the addresses they serve. For instance, if the addressee or the mail carrier omits to flip the delivery flag to indicate current status at the box, it cannot be determined remotely whether mail is in the box and this is even more of an issue at locked mailboxes, because they do not have delivery flags. Also, where an addressee does not return from work until after dark—which is common especially in northern states in the winter—they may not be able to see whether the mailbox has contents unless they are fortunate enough to be able to shine, for instance, a penlight or vehicle headlights into the interior of the mailbox. 
         [0012]    Consequently there is an ongoing need for improved mail boxes, and particularly for improved curbside mail boxes. 
       SUMMARY OF THE INVENTION 
       [0013]    The invention is an improved mailbox in which a sectional roll-up type door, in addition to enhancing the aesthetic appeal, facilitates access to the mail box contents, can be used in a weather-resistant way at the side or rear to avoid standing in traffic, and can also be used as a platform for insulation, solar collection, displays, lighting and various types of sensing of conditions at the interior of the mailbox such as the presence or absence of mail. The door moves along parallel tracks that are mounted in the interior of the box. 
         [0014]    In one non-limiting illustrative embodiment the invention is an improved mailbox, comprising:
   a) a housing that defines a mail receiving portion and a mail retrieval portion wherein:
       i) the mail receiving portion is selected from the group consisting of an upright doorway, a slot, a chute, a drawer, a hopper and a rotating drum; and   ii) the mail retrieval portion is an upright doorway selected from the group consisting of the mail receiving doorway and a non-receiving doorway;   
       b) a sectional roll-up type door, wherein:
       i) the door comprises sections that are pivotably attached to one another in a serial fashion;   ii) the door comprises track-riding means that are affixed at opposite lateral edges of the door;   iii) when closed, the door fills the mail retrieval doorway; and   iv) when open, the door is suspended in the interior of the housing; and   
       c) two parallel tracks that are mounted on opposite sides of the housing&#39;s interior, each track comprising an upright zone and a non-upright zone;
 
wherein the track-riding means of the sectional door are movably constrained within the parallel tracks thereby allowing the sectional door to be rolled up or down, wherein the door is fully closed when completely aligned with the parallel tracks&#39; respective closure zones and fully open completely aligned with the parallel tracks&#39; respective non-closure zones.
   
 
         [0024]    In another non-limiting illustrative embodiment the invention is an improved mailbox, comprising:
   a) a housing that defines a mail receiving portion that is an upright doorway;   b) a sectional roll-up type door, wherein:
       i) the door comprises sections that are pivotably attached to one another in a serial fashion;   ii) the door comprises track-riding means that are affixed at opposite lateral edges of the door;   iii) when closed, the door fills the mail retrieval doorway; and   iv) when open, the door is suspended in the interior of the housing; and   
       c) two parallel tracks that are mounted on opposite sides of the housing&#39;s interior, each track comprising an upright zone and a non-upright zone; and   d) a delivery indication flag that is pivotably or slidably mounted on one side of the exterior of the housing.
 
wherein the track-riding means of the sectional door are movably constrained within the parallel tracks thereby allowing the sectional door to be rolled up or down, wherein the door is fully closed when completely aligned with the parallel tracks&#39; respective closure zones and fully open completely aligned with the parallel tracks&#39; respective non-closure zones.
   
 
         [0033]    In a further non-limiting illustrative embodiment the invention is an improved mailbox, comprising:
   a) a housing that defines a mail receiving portion and a mail retrieval portion wherein:
       i) the mail receiving portion is located at a front side of the mailbox and is selected from the group consisting of an upright doorway, a slot, a chute, a drawer, a hopper and a rotatable drum; and   ii) the mail retrieval portion is an upright non-receiving doorway located at a lateral or rear side of the mailbox;   
       b) a sectional roll-up type door, wherein:
       i) the door comprises sections that are pivotably attached to one another in a serial fashion;   ii) the door comprises track-riding means that are affixed at opposite lateral edges of the door;   iii) when closed, the door fills the mail retrieval doorway; and   iv) when open, the door is suspended in the interior of the housing; and   
       c) two parallel tracks that are mounted on opposite sides of the housing&#39;s interior, each track comprising an upright zone and a non-upright zone;   d) a delivery indication flag that is pivotably or slidably mounted on oneside of the exterior of the housing;
 
wherein the track-riding means of the sectional door are movably constrained within the parallel tracks thereby allowing the sectional door to be rolled up or down, wherein the door is fully closed when completely aligned with the parallel tracks&#39; respective closure zones and fully open completely aligned with the parallel tracks&#39; respective non-closure zones.
   
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0044]      FIG. 1  is a caricature of a non-limiting illustrative embodiment according to the invention, depicting used of a sectional door at the front of a mailbox. 
           [0045]      FIG. 2  is a caricature of a non-limiting illustrative embodiment according to the invention, depicting used of a sectional door at the rear of a mailbox. 
           [0046]      FIG. 3  is a caricature of a non-limiting illustrative embodiment according to the invention, depicting used of a lockable sectional door that features a slot and an overhang. 
           [0047]      FIG. 4  is a caricature of a non-limiting illustrative embodiment according to the invention, depicting used of a sectional door at the side of a mailbox. 
           [0048]      FIG. 5A  is a caricature of a non-limiting illustrative embodiment according to the invention, depicting parallel tracks and a sectional door in closed position, in which the sectional door forms a complete arch. 
           [0049]      FIG. 5B  is a caricature of a non-limiting illustrative embodiment according to the invention, depicting parallel tracks and a sectional door in an open position, in which the sectional door has a hanging far end. 
           [0050]      FIG. 6  is a caricature of a non-limiting illustrative embodiment according to the invention, depicting parallel tracks and a sectional door in a closed position, that can be rolled down to achieve the open position. 
           [0051]      FIG. 8  is a caricature of a non-limiting illustrative embodiment according to the invention, depicting a mailbox that has a delivery slot at the front and a lockable sectional door at a lateral side. 
           [0052]      FIG. 8  is a caricature of a non-limiting illustrative embodiment according to the invention, depicting a mailbox that has a mail receiving portion on the upper front side and a lockable sectional door on the tower front side. 
       
    
    
     DETAILED DESCRIPTION 
     Definitions 
       [0053]    The invention may be better understood by reference to the following definitions of terms as used herein. 
         [0054]    The term “mail” means letters, packages and other items delivered by a public or private delivery service. 
         [0055]    The term “mailbox” means a receptacle at which mail is deposited for delivery to and optionally from a particular physical address. 
         [0056]    The term “housing” means a casing having a top, bottom, sides, and also featuring sufficiently large openings in the casing to permit the deposit of mail into and retrieval of mail from the interior of the casing. 
         [0057]    The term “mail receiving portion” as used with respect to a housing means the design feature(s) of the housing that allow passage of mail to its interior. Non-limiting illustrative design features of a mail receiving portion include doorways, slots, chutes and hoppers, any of which may be protected by a door, cover, or overhang. 
         [0058]    The term “mail retrieval portion” as used with respect to a housing means the feature(s) of the housing that allow opening of the housing to remove mail from its interior. In some embodiments the mail retrieval portion and mail receiving portion have some or all of their design features in common. A nonlimiting illustrative design feature of a mail retrieval portion is a doorway, that is protected by a sectional roll-up type of door and optionally by an overhang. 
         [0059]    The term “upright” as used with respect to a doorway, door, track or other feature means that the respective feature has a an orientation that is vertical or that deviates from vertical by 45 degrees or less. In non-limiting illustrative embodiments the deviation is no more than 5, 10, 15, 20, 25, 30, 35, 40, or 45 degrees. 
         [0060]    The term “doorway” as used with respect to a housing means an orifice in the housing, where the orifice has a size and shape that is suitable to permit a person&#39;s hand to extend into the interior of the housing while holding mail. The term doorway is used herein in a manner that includes both doorways and window openings. 
         [0061]    The term “slot” as used with respect to a housing means a long, narrow aperture in the housing. A non-limiting illustrative example of slot dimensions is 10 inches wide by 1.75 inches high. 
         [0062]    The term “chute” as used with respect to a housing means a sloping channel or slide by which mail may be transferred from the exterior to the interior of the housing. 
         [0063]    The term “hopper” as used with respect to a housing means a passageway having open ends and enclosed sides, by which mail may be transferred from the exterior to the interior of the housing, and which tapers downward in passage cross section size between the exterior and interior of the housing. 
         [0064]    The term “rotating drum” as used with respect to a housing means a drum or barrel that: can be pivoted about an axis; is located at least partly within and pivotably attached to the interior of the housing; and that has an orifice in a convex side into which mail may be deposited manually when the orifice is oriented to face a user, yet allows deposited mail to fall into a lower portion of the housing when the drum or barrel is pivoted such that the orifice faces that lower portion of the housing. 
         [0065]    The term “mail receiving doorway” as used with respect to a housing means a doorway through which mail may be deposited in the housing and optionally retrieved from the housing. 
         [0066]    The term “non-receiving doorway” as used with respect to a housing means a doorway through which mail may be retrieved from the housing but not delivered into the housing. 
         [0067]    The term “door” means a feature that in its closed position covers or otherwise blocks a feature through which mail may otherwise be transferred from the exterior to the interior of a housing and/or from the interior to the exterior. In some embodiments a door in its closed position seals a doorway in a housing. In certain embodiments the door is attached at its base to the exterior of a housing by a hinge or other pivot/bio mechanism. In alternative embodiments the door is slidable in a frame to move between open and closed positions. 
         [0068]    In referring to a door, the term “edge” means one of the door&#39;s upper, lower, and lateral edges as viewed when the door is held in an upright orientation. The term “side” as used with respect to a door means one of the broad faces of the door, e.g., its front side or rear side. The term “exterior-facing” as used with respect to a side of a door on a housing means the side of the door that faces away from the interior of the housing when the door is in a fully closed position. 
         [0069]    The terms “sectional roll-up type door” and “sectional door” are used interchangeably herein and mean a door for which a series of juxtaposed panels are attached at their adjacent edges in a manner that allows them to pivot relative to each other as if on a hinge. In some but not all embodiments the attachment permits the door to arch inwardly but not outwardly relative to an enclosed space. A non-limiting illustrative embodiment of the sectional roll-up type door design employed by the invention is a sectional roll-up type garage door. The term “roll-up” as used herein is generic and does not mean that only an upward rolling action of a door may open it. In some embodiments of the invention, rolling a door downward opens it and rolling the door upward closes it. In alternative embodiments of the invention, rolling a door from one side to the other opens it and rolling the door in the opposite direction closes it. In certain embodiments the door is comprised of a thermally insulating material. In addition other adaptation, such as but not limited to attaching a weight or spring to the door to facilitate stabilizing its position and/or its ease of motion, are also contemplated and within the scope of the invention. 
         [0070]    The term “section” as used with respect to a roll-up type door means one of the panels that form the door. 
         [0071]    The term “pivotably attached” as used with respect to two juxtaposed sections in a section roll-up type door means that they are attached at their adjacent edge in a manner that allows them to pivot relative to each other as if on a hinge. 
         [0072]    The term “serial fashion” as used with respect to pivotably attached panels in a sectional roll-up type door means that the door has a series of juxtaposed panels, each of which is pivotably attached on opposite edges to a neighboring panel, except that the terminal panels are each attached to only one respective neighboring panel. 
         [0073]    The term “track-riding means” as used with respect to a sectional roll-up type door means a feature that is attached to a lateral edge of the door, can mechanically engage with a track, and that, during opening and closing of the door, constrains that edge to move along a direction defined by that track. In particular embodiments the track-riding means rides over or inside a channel of the track. In non limiting illustrative embodiments the track-riding means is: a roller, i.e., a rolling wheel; a glider, i.e., a non-rolling part intended to slide; a pin, i.e., a piece that can hold a portion of a chain that moves along the track; or a rail, i.e., a piece having a large aspect ratio that is moved within a channel of the track—such as a rope through a channel or such as a long saddle on the track. Particular examples of illustrative track-riding means include those employed in sectional roll-up type garage doors but the invention is not so limited. 
         [0074]    The term “affixed” as used with respect to a track riding means and an edge of a door means that at least one portion of the track riding means is attached to the edge of the door or to a side of the door at a location that near one of its edges. 
         [0075]    The term “opposite lateral edges” as used with respect to a door means the edges at which the door moves between or along parallel tracks. 
         [0076]    The terms “fill” and “fills” as used with respect to a door for a doorway in a housing means that the door is in the closed position relative to that doorway and that the door in that position blocks passage of matter between the exterior and interior of housing through the doorway. 
         [0077]    The term “suspended in the interior” as used with respect to a sectional roll-up type door that is in open position in a housing means that the door has been moved further into the housing along parallel tracks to an open position, and that opposites edges of the door are held to the tracks by track-riding means. 
         [0078]    The term “two parallel tracks” as used with respect to a housing within which they are mounted in the interior, means tracks suitable for engaging mechanically with track-riding means of roll-up type door. Non-limiting illustrative embodiments include track designs of the types employed for sectional roll-up type garage doors, though the tracks of the present invention may be smaller in dimension and are not limited to that type. In a non-limiting illustrative alternative embodiment each track is a groove defined in a lateral side of the housing, or the tracks are symmetrically opposed grooves defined in the front and rear sides of the housing. 
         [0079]    The term “closure zone” as used with respect to a track means a portion of the track that, when mounted in the interior of a housing, stands along an entire edge of a sectional roll-up type door when the latter is in the fully closed position. In particular embodiments the closure zone is upright along most or all of its length, as the term upright is defined herein. In particular embodiments the closure zone is essentially linear along most or all of its length. In alternative embodiments the closure zone is curved along part or all of its length. 
         [0080]    The term “parallel complete convex arches” as used herein with respect to two parallel tracks in a housing means that their structure extends from the bottom of one wall of the interior of the housing, to an upper point that is optionally at the ceiling of the interior, and then down again to the bottom of the opposite wall of the interior. In particular embodiments a sectional door, when in the closed position, is as long as the entire arch length of such tracks such that it has the same full arch, and when in the open position has a portion of the sectional door that is either folded on the floor opposite the doorway or hanging optionally outside and lower than the floor portion of the box, e.g. by being passed through a slot. In certain desirable embodiments the sectional door is as long as the parallel compete convex arches and is thermally insulated to reduce the likelihood of temperature extremes in the box. 
         [0081]    The term “parallel concave arches” as used herein with respect to two parallel tracks in a housing means that their structure is in the housing&#39;s interior and extends from the top of a doorway to below the bottom of the doorway, and then across or below at least a portion of the floor of the interior of the housing. 
         [0082]    The term “non-closure zone” as used with respect to a track means a portion of the track that, when mounted in the interior of a housing, stands along an entire edge of a sectional roll-up type door when the latter is in the fully open position. In particular embodiments the non-closure zone is upright along most or all of its length, as the term upright is defined herein, while in other embodiments most or of the non-closure zone is not upright. In particular embodiments the non-closure zone is essentially linear along most of its length. In alternative embodiments the non-closure zone is curved along part or all of its length. In some embodiments the non-closure zone overlaps the closure zone; in other embodiments the closure zone is immediately adjacent but does not overlap the closure zone; and in still other embodiments the closure zone is neither adjacent to nor overlaps the closure zone. 
         [0083]    The term “movably constrained” as used with respect to track-riding means of a sectional door means that the track-riding means are held in place by the track to limit motion to one side or lateral edge when the door is not in motion, and are constrained to move along a course defined by the tracks when the door is in motion. 
         [0084]    The term “move in a coordination fashion” as used with respect to sectional doors guided by track-riding means on a parallel track means that serial adjacent sections follow each other in a cooperative sequence when the door is in motion. 
         [0085]    The term “completely aligned with” as used with respect to a sectional door in its physical position relative to a closure zone or a non-closure zone means that the respective zone stands along an entire edge of the door across all its component sequences, and that the respective zone is essentially the same length as that edge. 
         [0086]    The term “lock” has its usual and ordinary meaning for mailboxes and buildings, and includes but is not limited to key locks, combination locks and electronically controlled locks. 
         [0087]    The term “lockable” as used with respect to locking a lock from the exterior of a housing means that the locking mechanism can be activated by a key, combination, electronic signal or other means at a location that is on or near the outer surface of the housing. 
         [0088]    The term “define a slot” as used with respect to sections of a sectional door means that a slot is framed within a single panel and/or by multiple panels of the sectional door, as determined by the context of the use. 
         [0089]    The term “solar panel” has its usual and ordinary meaning in the field of solar technology, and concerns devices for the conversion of light energy into electrical energy. In some embodiments according to the invention the sectional door has at least one section that is a solar panel or has a solar panel mounted on its exterior surface, such that the solar panel is exposed to ambient light such as daylight or artificial light (e.g., under a street lamp) if they are present when the sectional door is in a fully or partially closed state. The exposure may be by location of the solar panel in or on one the exterior surface of one of the doorway-filling sections of the sectional door when it is in the closed position. Or the solar panel&#39;s exposure may be to light that passes through an opening such as a slot in the mailbox or through, e.g., a light conducting element of the mailbox, such as a transparent or translucent section of the sectional door that has exposure to ambient daylight or streetlight when the sectional door is in a fully or partially closed condition. In certain embodiments a section of the sectional door comprises a battery or capacitor that is in electrical communication with and charged by a solar panel that is likewise located in or on the same or a different section of the sectional door. Where a solar panel charges a battery or other energy storage device, the energy stored that way may be used to power other functional features that are located in or on the mailbox, whether the platform for the function is on the sectional door or otherwise. Due to the occasional opening and closing of the door, in a number of desirable embodiments it is least cumbersome and most efficient to locate ultimately solar-powered functions in or on an interior or exterior surface of the sectional door. 
         [0090]    The term “status display” means a display of a signal or of information. Particularly desirable embodiments of the invention, the status display concerns a condition in the interior of the mailbox, such as the presence (and/or absence) of new mail, the temperature, the humidity level, whether the box is in a locked state, and so forth. In various embodiments according to the invention the status display may be: a simple light such as a single light-emitting diode (LED); a lit screen such as an LED display; an iconic solid that is for instance a fish symbol, a butterfly symbol, a flower symbol, an awareness ribbon symbol such as for breast cancer or other cause, or the like; or may be another type of display. The status display may be battery powered or solar powered. The information for the status display may be provided from the interior of the mailbox. In particular embodiments a sensor inside the mailbox detects new mail, for example by: motion sensing when mail is placed there; sensing of blocking of a clear path such as an infrared beam is blocked by the presence of mail the path of the beam; pressure sensing of mail&#39;s weight on the floor of the box, or other means. A signal from the sensor then passes through an electrical circuit by wired or wireless means to activate the status display thereby indicating simple presence of mail, time of sensing, weight of mail, height of mail, or other information. In certain embodiments sensors are mounted on one or more sections of the door, and wires or wireless signals may pass from section to section of the door for communications use in sensing. In various embodiments sensors and or light sources act cooperatively with one another, such as where an infrared beam located at an interior surface of one section of the sectional door is directed at an infrared sensor that located at an interior surface of another section of the sectional door. In certain alternative embodiments, such as for iconic solids, a spring or tripwire is activated inside the mailbox when new mail is inserted into the interior, and tension from the interior spring or tripwire shifts the iconic solid from the “off” to the “on” status physical position (and/or vice versa) at the exterior of the box, which in some embodiments may be comparable to, e.g., the release mechanism of a spring-loaded mousetrap. 
         [0091]    The term “lighting source” means a source of light such for a light bulb, a light emitting diode, or other source of light. The term is not limited by the source of the energy for the light. In some embodiments the source may be powered from a battery, supercapacitor, electrochemical capacitor, fuel cell, solar panel, or other source of energy. In certain other embodiments the source may be a passive lighting source such as a material having phosphorescent properties that are renewed daily by exposure to daylight through, e.g., a slot in the mailbox or through a transparent or translucent section of the sectional door. 
         [0092]    The term “sensor” has its usual and ordinary meaning in the art. Thus for instance specific terms are used as follows: a motion sensor detects movement in a vicinity; pressure sensors detect an increase or alternatively a decrease in weight or physical pressure; clear path sensors (e.g., infrared sensors) detect blockage of a beam across a particular tine of sight (e.g., from side to side at the bottom of a mailbox, from end to end at the bottom of a mailbox, from top to bottom or vice versa in a mailbox, etc.); and so on. Use of additional types of sensors is also contemplated by the invention, such as for monitoring temperatures inside the mailbox, monitoring moisture levels inside the mailbox, monitoring whether the box is in a locked state when the sectional door is closed, and the like. 
         [0093]    The term “front” as used with respect to a curbside mailbox or wall-mounted mailbox means the side on which mail is inserted for final delivery, which typically though not necessarily faces the road. The term “front” as used with respect to a community mail station means the side at which mail is retrieved by addressees. The terms “located at an upper portion” and “located at a lower portion” as used with respect to features on the front side of a mailbox mean respectively their location at the upper and lower ends of the front of a mailbox. The “rear” of the mailbox is on the opposite side from the front, and the two “sides” are lateral and between the front and rear. 
         [0094]    The term “curbside mailbox” has its usual and ordinary meaning, and means a mailbox that stands at one side of a road. In particular embodiments the curbside mailbox is mounted on the top or side of a post that rises from the ground. In certain embodiments the curbside mailbox is encased in a shroud that rises from the ground and is comprised of brick, wood or other materials, where the shroud encases the top and bottom of the mailbox and some or all of the sides and rear of the mailbox. In some embodiments the curbside mailbox is one of a cluster of mailboxes that are placed in serial and/or stacked array. 
         [0095]    The term “community mail station” has its usual and ordinary meaning in the art, and means a group of mailboxes that are constructed in serial or stacked fashion and located at a common mail pick-up point for a group of addresses. 
         [0096]    The terms “mounted on a wall” and “wall-mounted” as used with respect to a mailbox are synonymous and mean a mailbox that is affixed to a wall. 
         [0097]    The terms “traditional”, “contemporary” and “locking” as used with respect to United States Postal Service (USPS) categories mailbox designs, have the meaning assigned to those terms by the USPS. Where the description of the invention refers to a housing that, apart from its sectional door and retrieval portion, has such a profile, it means that in the absence of those features according to the invention the mailbox design in view would otherwise fall within the referenced USPS category or categories. 
         [0098]    The terms “ferrous metals”, “non-ferrous metals”, “polymers”, “wood”, “glasses” and “ceramics” have their usual and ordinary meaning in the arts of chemical compositions and materials science. 
         [0099]    The term “primarily comprised” as used herein with respect to the chemical composition of housing materials and sectional door materials, means that over 50 percent by weight of the referenced material is comprised of the recited chemical composition. 
         [0100]    The term “thermally insulating” has its usual and ordinary meaning, and refers to a physical effect of slowing the rate of heat transfer across a material or object. In particular, the term “thermally insulating” as used herein with respect to a sectional door means that the door is insulated to limit heat transfer rates from one side of the door to the other. 
         [0101]    The term “overhang” and “extends over” as used herein with respect to a housing, refers to a feature located at an upper exterior position on the housing, that is positioned above and extends beyond another portion of the housing. Non-limiting illustrative embodiments of such overhangs include a roof extension, an cave and an awning, where those features have a size that is less than and suitable for use on a mailbox. 
         [0102]    The term “delivery indication flag” refers to mailbox flags in their usual and ordinary meaning. Non-limiting illustrative embodiments include stiff red objects having a such as that of a semaphore flag or a trapezoid, which are each attached to an exterior lateral side of a respective housing of a mailbox in a manner that allows the respective flag to pivot or slide from a non-signaling to signaling position. 
         [0103]    The term “handle” has its usual and ordinary meaning in the art, and its meaning herein is not limited by the design or location of the handle. Non-limiting illustrative examples of handles include: tabs; straps; inset handles; orifices; drawstrings; handles of the designs found on doors, cabinets, chests, dressers, appliances and tools; and the like. 
       FIGURES 
       [0104]    The invention can be further understood by reference to the figures.  FIG. 1  depicts a caricature of one embodiment of a mailbox according to the invention. The housing ( 10 ), has a front side ( 20 ) at which mail can be delivered and retrieved. A sectional door ( 100 ) is in a closed position and has a handle ( 105 ) of an inset style near the bottom. A delivery indication flag ( 30 ) is upright in the signaling position, and is located on the usual side for such flags in the United States. The opposite side from the flag is the non-flag side of the mailbox ( 26 ). 
         [0105]      FIG. 2  illustrates another embodiment of the invention. This provides a rear view of a mailbox. At the rear side ( 22 ) of the mailbox housing ( 10 ) is a sectional door ( 100 ) that has been provided with a dowel-type handle ( 105 A). Such a handle can serve as a door stop when the sectional door is raised. Also depicted is a delivery indication flag ( 30 ) that is pivotably attached at its base to the flag side ( 24 ) of the mailbox housing. Rear doors in a curbside box are desirable for retrieving mail from, e.g., a sidewalk instead of standing in or adjacent to the street. 
         [0106]      FIG. 3  illustrates an embodiment that has certain other variations. This provides a front view of a mailbox that is mounted on a pole ( 50 ). At the front side ( 20 ) of the mailbox housing ( 10 ) is a sectional door ( 100 ) in which is a slot ( 110 ) for mail delivery that is framed by three of the sections of the sectional door. The sectional door is lockable on flag side ( 24 ) of the housing by a key lock ( 40 ) in this case, the lock being located toward the front end of the flag side. In this illustration the flag ( 30 ) is depicted in the lowered—i.e., non-signaling—position. The sectional door is protected from the elements by an overhang ( 15 ) and by a traditional mailbox door ( 60 ) that is hinged ( 65 ) at the bottom. 
         [0107]      FIG. 4  depicts an embodiment that has a sectional side door in the non-flag side. A door in that location enables the user to remain off the street and to watch oncoming traffic while retrieving mail. Mailboxes that are located on the edge or curb of a street that has sharp curves, are periodically knocked down by fast drivers who unintentionally run off the road, thus the ability to comfortably face traffic while retrieving mail is not a trivial benefit. In this particular embodiment the sectional door ( 100 ) is in a closed position. The sectional door is associated with parallel tracks ( 201  and  202 ) that are affixed on the interior surface of the mail box on the non-flag side; the tracks in this embodiment run from near the floor of the mailbox to almost the top of the dome. In this embodiment the mailbox is otherwise comparable to a Joroleman mailbox, having a front door ( 60 ) that is hinged ( 65 ) at its base, and also having an indicator flag ( 30 ). Parenthetically, note that the double lines employed to depict each of  201  and  202  are simply a device for graphic convenience to illustrate width dimensions; in fact each track may be formed from a single piece of material. 
         [0108]      FIG. 5A  illustrates additional options and features of sectional doors in use according to the invention. In this case, for ease of viewing, only the parallel tracks ( 201  and  202 ) and the sectional door ( 100 ) are shown, and they are depicted in the orientation that they would have in a rectangular dome mailbox if the sectional dome formed a complete archfrom one side to the other. The track-riding means of the sections are also omitted in order to simplify the Figure. The view is from the front of the box. One section ( 100 A) of the door is brought down for full closure. The far opposite section ( 100 B) of the door will be lower still when the door is opened. This arch is a particularly desirable configuration when the sections of the door are comprised of insulating material, because the design buffers against extremes of temperature and better protects medicines, consumer products and the like from damage from heat or cold. Also, although the sectional door is shown in an arch from side to side, it is merely illustrative of the general paradigm: an arch according to the invention can also be formed from end to end within a mailbox. 
         [0109]      FIG. 5B  depicts the same design and features as  FIG. 5A , except that in  FIG. 5B  the sectional door has been raised on the non-flag side, thus the far side of the door now extends below the floor level for the parallel tracks. In such an embodiment the far sections, e.g.,  100 B, require either a slot or other accommodation for their hanging distance, or alternatively a track along which they can run on or under the floor, or an accommodation that allows at least some of the flag side door sections in the arch to fold and collapse into a pile when the non-flag side is lifted to open the door. 
         [0110]    The tracks in  FIGS. 5A and 5B  are shown as semi-circular but for example they may instead be constituted of a combination of linear sections and corner elbow sections, just as garage door tracks are. The same is true in  FIG. 6 , which illustrates another feature. In this depiction the parallel tracks ( 201  and  202 ) have their highest point just above the sectional door  100  when it is in the closed position as stipulated for this drawing. The tracks extend downward well below the bottom of the sectional door when it is in the closed position. Thus here panel  100 A is moved up instead of down to close the door, and the door is opened by moving it downward. In this particular design the tracks may run along the floor of a mailbox. Or for instance by using a false bottom the track may run underneath the mail-holding floor of the mailbox, lest the delivered mail be deformed, torn or soiled by track grease upon coming into comes into contact with the track on the mailbox interior floor where mail typically rests. 
         [0111]      FIG. 7  illustrates another embodiment. Here a housing ( 10 ) defines a slot ( 210 ) through which incoming mail may be delivered. Such a slot is commonly used where mail is only received and not posted for delivery elsewhere, and the slot&#39;s dimensions and orientation can serve theft prevention objectives. A sectional door ( 110 ) is located at the bottom of one side of the box, and can be locked in place by a nearby lock ( 40 ), which in this example is a key lock but the invention is not so limited. Such a box design is suitable for placement on a pole or pedestal as at a curbside or be integrated with a supporting barrel or carton. Where the sectional door is in the back or front of the mailbox instead of on the side, mailboxes such as this one may be placed in series or stacked as at a community mail center. 
         [0112]      FIG. 8  depicts yet another embodiment, which can stand alone as at a curb on a pole or in a shroud, and due to its cuboid shape is even more suitable for stacked arrays in a community mail center. Here the housing ( 10 ) has at the upper portion of its front side a fixed slot, a chute, a door that pivots about its base to a limited extent, or other receiving means ( 220 ). In the lower portion of the front side a sectional door ( 100 ) has a lock ( 40 ) mounted on the door itself. 
         [0113]    The foregoing description and drawings comprise illustrative embodiments of the preferred embodiment, but the invention is not so limited, it will be readily apparent to those of ordinary skill in the art that numerous alternatives, variations, modifications and permutations of the invention described herein may be made without departing from the spirit or nature of the invention; these are contemplated as being part of the invention. Also, merely listing the components of a device in a certain physical relationship does not constitute a limitation on their physical relationship in the device. Although specific terms are employed herein, they are used in descriptive sense only and not for purposes of limitation.