Abstract:
An apparatus for a damper cap for a chimney flue includes a top plate having dimensions conforming to a top of the chimney flue. A bird and animal screen is joined to and extends from a bottom of the top plate. The screen has dimensions for insertion into the chimney flue. A rod joined to a center of the top plate extends downward into the chimney flue. A support structure is secured to an interior of the chimney flue. A mechanism is joined to the support structure and the rod for moving the rod in a vertical direction. In an open position the top plate is above the chimney flue to allow smoke to exit and the screen restricts birds and animals from entering. In a closed position the top plate is proximate the chimney flue restricting airflow into and out of the chimney flue and the apparatus is retracted into the flue.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present Utility patent application claims priority benefit of the U.S. provisional application for patent Ser. No. 61/020,707 filed on Jan. 12, 2008 under 35 U.S.C. 119(e). The contents of this related provisional application are incorporated herein by reference for all purposes. 
     
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER LISTING APPENDIX 
       [0003]    Not applicable. 
       COPYRIGHT NOTICE 
       [0004]    A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure as it appears in the Patent and Trademark Office, patent file or records, but otherwise reserves all copyright rights whatsoever. 
       FIELD OF THE INVENTION 
       [0005]    The present invention relates generally to chimney caps. More particularly, the invention relates to a retractable chimney damper cap that cannot be seen on the outside of the chimney. 
       BACKGROUND OF THE INVENTION 
       [0006]    Homeowners who have one or more masonry fireplace flues in their home are loosing energy from their furnace through these chimney flues. Dampers mounted above the fireboxes are not airtight, and even if the dampers are closed much energy is still lost up the flues. When the wind is blowing, the wind often comes down the flue and makes the home much colder, requiring the furnace to kick on needlessly. In the warm months, the air conditioner is pulling warm air down the flue unintentionally. This puts a heavy demand on the compressor, using more energy and causing wear and tear on the compressor. Fireplace flues may also allow rain to enter the system. Virtually, there is a square foot hole in the roof where the flue is. Furthermore, rain, birds, raccoons, snakes, rats, squirrels and other pests can enter the open flue at the top and cause problems. 
         [0007]    There are chimney damper caps available to seal flues. However, current chimney caps sit on top of the flue. These caps often have a cold industrial look and resemble a birdcage, which is a look that some people do not like. Also, currently known chimney damper caps are spring loaded and require a lot of force to pull the cap closed. Elderly people in particular may have trouble manipulating these designs. Other currently known chimney caps require driving four heavy screws, two on each side, into the flue tile to mount these caps on top of the flue. This is troublesome since terracotta flue tile has a surface glaze from being fired in a kiln. This glaze should never be drilled or altered in any way since a crack or hole in this glaze may enable freezing rain to seep into the flue and cause the flue to crack and weaken and fails to prevent wind from blowing the cap off. The two leading damper caps in the United States require the purchase of a lid and screen in order to prevent birds, squirrels, raccoons, and other pests from entering the flue, making it necessary to purchase two separate products to solve all of the problems incurred with chimney flues. 
         [0008]    One specific prior art damper cap, which is one of the leading commercially successful chimney damper caps on the market, has no bird and animal screen. Raccoons are the most notorious animal to break into houses via open chimney flues, and the springs around the perimeter of this cap cannot keep desperate raccoons from entering the flue and nesting in the bottom smoke chamber. Therefore a separate rain cap with a bird and animal screen design is often required to be used with this damper cap. Also this design is difficult or impossible to open in severe ice and snow. The springs in this cap are not strong enough to lift the load. Another similar prior art damper cap uses a second product, a rain cap with a screen, to go over top of the cap to prevent failure when ice and snow mount on top and to prevent animal intrusion. Another exemplary prior art damper cap also has no bird and animal screen, and, if a homeowner forgets to close the lid, an animal has plenty of room to enter the home via this damper cap design. Also the present damper cap does not function properly in severe ice and snow, and may fail from the load. To resolve this, the inventor offers a lid and screen in a separate unit, as in the previous prior art example. Therefore, two products must be purchased to meet the total needs of the homeowner. The need for a second cap unit in these prior art examples is not ideal. In another similar prior art damper cap, a lever device is provided for attempting to hammer the lid open when frozen shut from ice. This mechanism works in light frost; however, if the lid is completely filled with rain, held on top of the lid by the outer perimeter of the outer walls, thick ice forms, and the lid typically does not open. Furthermore, this design has no bird and animal screen and sits on top of the flue, which is unsightly to many. 
         [0009]    In another prior art chimney damper cap without a bird and animal screen, the lid moves up and down; however, the holding mechanism is spring loaded and not practical for easy fabrication or installation. Also, this damper cap is not universal. In this design the cap is supported by expandable tumbuckles anchored in sockets formed in the chimney liner, and in order to attach this device to a flue, holes must be drilled into the terracotta flue tile. This procedure may cause the flue tile to crack, and if the lid is left open and freezing rain enters, the flue may break. Furthermore, it is very difficult and dangerous to drill down inside a flue, especially when standing on a second or third story ladder. It is also a disservice to the homeowner to form sockets in their flue as freezing rain may enter the sockets themselves and expand and break the flue, causing much damage in time. An experienced professional chimney sweep would never drill into a flue liner to attach a damper cap. 
         [0010]    Other prior art damper caps have attached lids and animal screens in one unit. These damper caps sit in a stationary position on top of the flue, and each have a spring-loaded additional lid inside the outer lid and screen. This design is held into place by four spring-loaded levers attached to the four corners. The multiple lids make this design complicated and expensive to manufacture. Another prior art damper cap comprises a damper flap with a bird and animal screen. The damper flap is automatic and electrically controlled, which makes it costly to make and difficult to install. Furthermore, this design is unsightly to many since it sits on top of the flue. 
         [0011]    Yet another prior art damper cap is electrically controlled to open and close automatically when sensing smoke in the flue. This design has no bird and animal screen and uses relays and double pull switches, motors and smoke detectors. This design is extremely complicated to manufacture and is expensive. Another very complicated and costly prior art damper cap provides a brake mechanism said to prevent unwanted damper closure. However, this damper cap is impractical in nature and also difficult to install. Furthermore, this design does not include a bird or animal screen. 
         [0012]    Yet other prior art damper cap designs are hinged to one side of the flue and open much like a book. In these designs one side of the damper cap is bound and three sides are free. This is a problem in windy conditions where these designs may blow shut and cause smoke problems or blow backwards and bend or break. Furthermore, these designs do not include a bird and animal screen. Another prior art damper cap design has a cross member that holds the lid in place. However, this cross-member prevents the lid from closing tightly, making it impossible to save costly energy. This design allows furnace air to escape, and allows cold wind to blow into the home. Also, this design does not have a bird and animal screen. Yet another prior art damper cap design has a tube that holds a spring that lifts the lid. However, this spring can fail from creosote building up inside the tube. Furthermore, this design does not include a bird and animal screen. 
         [0013]    In view of the foregoing, there is a need for improved techniques for providing a chimney or damper cap that cannot be seen on the outside of the chimney, seals tightly, is easy to open and close, is easy to install, and generally prevents pests, rain, snow, and debris from entering the chimney flue. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which: 
           [0015]      FIGS. 1A ,  1 B and  1 C illustrate an exemplary retractable damper cap, in accordance with an embodiment of the present invention.  FIG. 1A  is a cross sectional view of damper cap installed in a chimney flue,  FIG. 1B  is a cross sectional view of a pulley assembly as indicated by section A-A in  FIG. 1A , and  FIG. 1B  is a side view of the damper cap not attached to a chimney flue. 
       
    
    
       [0016]    Unless otherwise indicated illustrations in the figures are not necessarily drawn to scale. 
       SUMMARY OF THE INVENTION 
       [0017]    To achieve the forgoing and other objects and in accordance with the purpose of the invention, a retractable hideaway chimney damper cap is presented. 
         [0018]    In one embodiment, an apparatus for a damper cap for a chimney flue is presented. The apparatus includes a top plate having dimensions conforming with a top opening of the chimney flue. A bird and animal screen is joined to and extending from a bottom surface of the top plate. The bird and animal screen includes dimensions suitable for insertion into the top opening of the chimney flue. A rod joined to a center of the top plate extends downward into the chimney flue. A support structure is configured to be secured to at least two sides of an interior surface of the chimney flue. The support structure constrains horizontal movement of the rod. A mechanism is joined to the support structure and the rod for moving the rod in a vertical direction, where, in an upward open position, the top plate is at a sufficient distance above the top opening of the chimney flue to allow smoke to exit the chimney flue and the bird and animal screen extends downward to at least the top opening of the chimney flue substantially restricting birds and animals from entering the chimney flue. In a downward closed position, the top plate is proximate the top opening of the chimney flue substantially restricting airflow into the chimney flue and the apparatus is substantially retracted within the flue. In another embodiment the mechanism further includes at least one pulley and a cable in engagement with the pulley. The cable is joined to a distal end of the rod and extends downward through the chimney flue to a firebox where, when the cable is pulled, the rod is raised to the upward open position. When the cable is released, the rod is lowered to the downward closed position. A further embodiment includes a hook positioned within the firebox for securing the cable when the rod is in the upward open position. Another embodiment further includes a cable retainer for retaining the cable in a groove of the at least one pulley and allowing the at least one pulley to freely rotate. Yet other embodiment further include a sealing flange joined to the top opening of the chimney flue, the sealing flange including an opening dimensioned to receive the bird and animal screen where, when the rod is in the downward closed position, the top plate rests on a top of the sealing flange and a gasket disposed between the sealing flange and the top plate to provide a seal in the downward closed position. Still another embodiment further includes a cap stop angle joined to a distal edge of the bird and animal screen where, when the rod is in the upward open position, the cap stop angle contacts a lower surface of the sealing flange. In another embodiment the support structure further includes at least two lower arms. Each of the lower arms includes an engaging end configured for engaging the interior surface of the chimney flue, a lower pivot point and an upper pivot end. The lower arms are joined at the lower pivot point for rotation about the pivot point. At least two upper arms are included. Each of the upper arms includes a lower pivot end pivotally joined to a one of the lower arms upper pivot end and a pivoting end. Each of the pivoting ends is pivotally joined to the at least one pulley where, when a downward force is applied to the pivoting ends, the engaging ends move outward engaging the interior surface of the chimney flue and thus secures the apparatus. Various other embodiment further include flue cleats joined to the engaging ends for providing addition friction on the interior surface of the chimney flue and a rod guide for constraining horizontal movement of the rod. 
         [0019]    In another embodiment an apparatus for a damper cap for a chimney flue is presented. The apparatus includes means for damping the chimney, means for restricting birds and animals from entering the chimney flue, means for supporting the apparatus in the chimney flue and means for moving the damping means and the restricting means to an open position for allowing smoke to exit the chimney flue and substantially restricting birds and animals from entering the chimney flue, and to a closed position for substantially restricting airflow into the chimney flue where the apparatus is substantially retracted within the chimney flue. Yet other embodiments further include means for operating the moving means from a firebox and means for sealing the damping means to the chimney flue. 
         [0020]    In another embodiment an apparatus for a damper cap for a chimney flue is presented. The apparatus includes a top plate having dimensions conforming to a top opening of the chimney flue. A bird and animal screen is joined to and extends from a bottom surface of the top plate. The bird and animal screen has dimensions suitable for insertion into the top opening. A cap stop angle is joined to a distal edge of the bird and animal screen. A sealing flange is joined to the top opening of the chimney flue. The sealing flange has an opening dimensioned to receive the bird and animal screen. A rod is joined to a center of the top plate for extending downward into the chimney flue. A support structure is configured to be secured to at least two sides of an interior surface of the chimney flue. The support structure constrains horizontal movement of the rod. A mechanism is joined to the support structure and the rod for moving the rod in a vertical direction. The mechanism includes at least one pulley and a cable in engagement with the pulley. The cable is joined to a distal end of the rod and extends downward through the chimney flue to a firebox. When the cable is pulled the rod is raised to an upward open position where the cap stop angle contacts a lower surface of the sealing flange and the top plate is at a sufficient distance above the top opening of the chimney flue to allow smoke to exit the chimney flue and the bird and animal screen substantially restricts birds and animals from entering the chimney flue. When the cable is released the rod is lowered to a downward closed position where the top plate rests on a top of the sealing flange substantially restricting airflow into the chimney flue and the apparatus is substantially retracted within the flue. The top plate and bird and animal screen can be raised easily under severe weather conditions and when retracted the bird and animal screen is hidden from view. Various other embodiments further include a hook positioned within the firebox for securing the cable when the rod is in the upward open position and a cable retainer for retaining the cable in a groove of the at least one pulley and allowing the at least one pulley to freely rotate. Yet another embodiment further includes a gasket disposed between the sealing flange and the top plate to provide a seal in the downward closed position. In another embodiment the support structure further includes at least two lower arms. Each of the lower arms includes an engaging end configured for engaging the interior surface of the chimney flue, a lower pivot point and an upper pivot end. The lower arms are joined at the lower pivot point for rotation about the pivot point. At least two upper arms are included. Each of the upper arms includes a lower pivot end pivotally joined to a one of the lower arms upper pivot end and a pivoting end. Each of the pivoting ends is pivotally joined to the at least one pulley. When a downward force is applied to the pivoting ends, the engaging ends move outward engaging the interior surface of the chimney flue and thus secures the apparatus. Various other embodiments further include flue cleats joined to the engaging ends for providing additional friction on the interior surface of the chimney flue and a rod guide for constraining horizontal movement of the rod. 
         [0021]    Other features, advantages, and object of the present invention will become more apparent and be more readily understood from the following detailed description, which should be read in conjunction with the accompanying drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    The present invention is best understood by reference to the detailed figures and description set forth herein. 
         [0023]    Embodiments of the invention are discussed below with reference to the Figures. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments. For example, it should be appreciated that those skilled in the art will, in light of the teachings of the present invention, recognize a multiplicity of alternate and suitable approaches, depending upon the needs of the particular application, to implement the functionality of any given detail described herein, beyond the particular implementation choices in the following embodiments described and shown. That is, there are numerous modifications and variations of the invention that are too numerous to be listed but that all fit within the scope of the invention. Also, singular words should be read as plural and vice versa and masculine as feminine and vice versa, where appropriate, and alternative embodiments do not necessarily imply that the two are mutually exclusive. 
         [0024]    The present invention will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings. 
         [0025]    Preferred embodiments of the present invention provide retractable chimney damper caps that seal chimney flues and keep out rain and pests and do not detract from the design of the home. In preferred embodiments, the screen cap drops down inside the flue rather than sitting on top of the flue, hiding the cap from view so that it does not detract from the architectural integrity of the house. Preferred embodiments comprise no springs and use the weight of the cap to close the cap, making them very easy to open and close. Preferred embodiments also comprise a pulley system that lifts the lid and screen very easily and enables the cap to open even in severe ice and snow. Preferred embodiments can be opened easily with only a user&#39;s little finger. Preferred embodiments are held securely in place inside the flue without drilling or altering the flue, and require only one hole to be drilled in the firebox for installation.. This makes preferred embodiments much easier to install than some prior art solutions. Also, preferred embodiments combine the damper cap and a bird and animal screen into one unit, which is much cheaper than and easier to install than prior art caps requiring a separate bird and animal screen to seal the flue from generally all unwanted intrusions in the open or closed position. Typically, in preferred embodiments, no ice can form on top of the lid to cause difficulties, as the lid is flat and smooth allowing rain to run off and away from cap and flue before freezing into ice. If ice forms around the perimeter of lid and gasket that is 3/16 of an inch above flange, it is still very easy to open with the pulley mechanism. Furthermore, the damper cap in preferred embodiments will generally not fall shut accidentally. 
         [0026]      FIGS. 1A ,  1 B and  1 C illustrate an exemplary retractable damper cap  101 , in accordance with an embodiment of the present invention.  FIG. 1A  is a cross sectional view of damper cap  101  installed in a chimney flue  100  in a raised position,  FIG. 1B  is a cross sectional view of a pulley assembly  107  as indicated by section A-A in  FIG. 1A , and  FIG. 1C  is a side view of damper cap  101  not attached to a chimney flue. Referring to  FIGS. 1A and 1C , damper cap  101  in the present embodiment comprises a sealing flange  102 , a cap stop angle  103 , and a top plate  105  preferably made of ⅛ inch thick aluminum and a bird and animal screen  104  preferably made of expanded aluminum mesh. Adhered to the underside and outer perimeter of top plate  105  is a 1/16 inch thick×1 inch wide silicone rubber gasket  124 , to insure a hermetic seal between top plate  105  and sealing flange  102 . However, various different materials may be used to construct the elements of damper cap  101  in alternate embodiments. For example, without limitation, different types of metal may be used, and plastic may be used for some elements such as, but not limited to, bird and animal screen  104  and sealing flange  102 . Carbon steel, stainless steel, aluminum and high temperature plastics are ideal materials for construction of present embodiment. Furthermore some alternate embodiments may be implemented without a sealing flange or rubber gasket. 
         [0027]    Referring to  FIG. 1A , sealing flange  102  is attached to flue  100  with adhesive. Sealing flange  102  is not attached to bird and animal screen  104  to enable bird and animal screen  104  to be raised and lowered through sealing flange  102 . In the present embodiment, pulley assembly  107  raises and lowers damper cap  101 . Referring to  FIGS. 1A and 1B , pulley assembly  107  comprises lower arms  106  with flue cleats  108 , upper arms  109 , a stationary pivot pin  110 , a pulley pivot pin  111 , a pulley  112 , a cable retainer  113 , a push rod guide  114 , a push rod  115 , a cable  117 , and an actuator chain  116 . Flue cleats  108  provide additional friction to hold pulley assembly  107  in place. Flue cleats  108  are optional and may not be included in alternate embodiments. Upper arms  109  and lower arms  106  are coupled together at joints  118  so that both sets of arms may rotate around joints  118 . In the present embodiment, joints  118  are riveted; however, in alternate embodiments other coupling methods may be used such as, but not limited to, nuts and bolts. In an alternate embodiment, upper arms  109  and lower arms  106  could be the same length and assembled in the shape of a diamond, much the same as a scissor jack, with push rod guide  114  running from the top of the diamond shaped arms to the bottom. At the right and left joints flue cleats may or may not be attached. When nut  119  is tightened the pivot pin mechanism  110  and pulley pivot pin  111  mechanisms spread the diamond shaped scissor jack into the alternate sides of the flue holding assembly in place. One end of cable  117  is attached to actuator chain  116 . Then cable  117  is wrapped around pulley  112 , and the opposite end of cable  117  is attached to the lower end of push rod  115 . This enables a user to raise damper cap  101  by pulling actuator chain  116 . Alternate embodiments may have a longer cable without an actuator chain so that a user pulls the cable instead of a chain to raise the damper cap. In the present embodiment, pulley  112  is held in place on pivot pin  111  by cotter pin  120 ; however, in alternate embodiments various means may be used to hold pulley  112  onto pivot pin  111  such as, but not limited to, screws, caps on the pin, nuts, etc. In the present embodiment, cable retainer  113  must allow pulley  112  to rotate freely around pivot pin  111  and hold cable  117  into groove of pulley so that cable  117  may move rod  115  up and down freely. 
         [0028]    Referring to  FIG. 1A , in order to install the present embodiment, a user first adheres sealing flange  102  to flue  100  with silicone adhesive and then centers push rod  115  within flue  100 . The user may use a setting tool to assist in this. Then the user inserts pulley assembly  107  into flue  100  until the top of push rod  115  is even with the top of flue  100 . The push rod is held temporarily in a stationary position in hollow tube rod guide  110  by the cotter pin  125  that is inserted into holes near the top of the hollow tube  114 , and then through a hole in push rod  115 . It is necessary to line these holes up to allow cotter pin  125  to be inserted. The user then turns nut  119  clockwise, pushing pulley pivot pin  111  down and causing lower arms  106  to extend outward toward the walls of flue  100 . When lower arms  106  engage the walls of flue  100 , nut  119  is tightened, preferably with a wrench, until pulley assembly  107  is secure. If a setting tool was used to center push rod  115 , the user now removes the setting tool and the cotter pin  125  from hollow tube  110  used to hold rod  115  in place for installation and installs cap damper  101  by inserting push rod  115  through a hole in the center of cap top plate  105  and resting cap top plate  105  on a nut  121  at the top of push rod  115 . Then the user attaches hitch pin spring clip  122  to the top of push rod  115  to hold cap top plate  105  in place. In alternate embodiments other means may be used to hold cap top plate  105  in place such as, but not limited to, a nut, a cotter pin, a cap, etc. In some applications, the sealing flange could be screwed on to the flue; however, it is often not suitable to drill into terracotta flue tile material. Once damper cap  101  is installed on push rod  115 , push rod  115  may be slid up and down within hollow threaded tube rod guide  114  causing cap top plate  105  and bird and animal screen  104  of damper cap  101  to move up and down in and out of flue  100 . In an alternate embodiment, the four sided bird screen  104 , that is attached to lid  105 , could be eliminated, and one piece of screen  104  could be cut to the same size as sealing flange  102  and inserted under sealing flange  102  prior to adhesion. It would be positioned in such a way as to allow push rod  115  to move lid  105  up and down through an existing opening in said screen. The user then drills a hole in the firebox at a mortar joint and installs a hook  123 . In some embodiments this hook may be secured in the firebox with a lag shield and lag screw. The hook may be located, or hidden away above the line of sight on the firebox wall in some embodiments to avoid drilling a hole where it would be visible on the firebox wall.. 
         [0029]    In typical use of the present embodiment, the weight of damper cap  101  forces push rod  115  down through rod guide  114 , and bird and animal screen  104  drops down inside flue  100  in the closed position when not in use. Sealing flange  102  helps to form an airtight seal with cap top plate  105  at the top of flue  100 . In some embodiments a rubber gasket  124  may be adhered to the under side of cap top plate  105  to further help create an airtight seal; however, this gasket is optional and may not be included in some embodiments. In some embodiments, cap top plate  105  may rest on flue  100  without a sealing flange or a gasket. When the user wishes to open damper cap  101  using the present embodiment, the user pulls actuator chain  116  downward to raise damper cap  101 . To hold damper cap  101  in the open position the user hooks actuator chain  116  on hook  123 . The pulley system of the present embodiment enables damper cap  101  to be opened very easily even in severe ice and snow. In prior art damper caps, it is important to have tension on the cable to hold the lid closed to prevent incoming and outgoing air movement. However, the present embodiment requires no tension on cable  117  to remain closed; instead, damper cap  101  is closed and held in the closed position by gravity and its own weight. 
         [0030]    An alternate embodiment of the present invention may be implemented without a pulley mechanism to lift the damper cap. Instead, in this embodiment, one end of a long spring is attached to the bottom of the push rod and the other end of said spring is attached to a stationary part of a holding mechanism that holds the device in place in the flue. Releasing the cable from the mounted bracket on the firebox wall causes the tension of the spring to lift the rod and at the same time lift the attached damper cap. Pulling down on the cable closes the damper cap. 
         [0031]    Other alternate embodiments may comprise various different means for raising and guiding the push rod. For example, without limitation, in one alternate embodiment, the push rod may comprise a worm gear assembly at the pulley that raises and lowers the push rod. In another alternate embodiment, a chain and gear may be used in place of the pulley and cable. In yet another alternate embodiment, the push rod is replaced by a ratcheting rack and the pulley comprises a toothed gear that engages with this rack to raise the rack, which is attached to the damper cap. This embodiment also comprises a second cable attached to a release mechanism on the rack in order to release the gear from the rack and lower the damper cap. 
         [0032]    Yet other alternate embodiments may employ various different means for holding the pulley assembly in place. The preferred embodiment illustrated by way of example in  FIG. 1A  comprises a linkage assembly with two upper arms  109  and two lower arms  106  that expand to fit within a chimney flue. Alternate embodiments may comprise more arms for example without limitation, four upper arms and four lower arms to engage with all four walls within the chimney flue. This embodiment may be more complicated to manufacture yet may provide more stability when installed. Other alternate embodiments may comprise spring-loaded arms to hold the pulley assembly in place. Another alternate embodiment may comprise a sleeve that slides down into the chimney flue onto which various elements of the pulley assembly and damper cap may be attached. 
         [0033]    Having fully described at least one embodiment of the present invention, other equivalent or alternative methods of providing chimney damper caps that cannot be seen on the outside of the chimney according to the present invention will be apparent to those skilled in the art. The invention has been described above by way of illustration, and the specific embodiments disclosed are not intended to limit the invention to the particular forms disclosed. For example, the particular implementation of the damper cap may vary depending upon the particular type of bird and animal screen used. The bird and animal screens described in the foregoing were directed to implementations that slide into the chimney; however, similar techniques are to provide bird and animal screens made of collapsible materials such as, but not limited to, fine mesh, folding lattices, hinged materials, etc. Collapsible implementations of the present invention are contemplated as within the scope of the present invention. The invention is thus to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the following claims.