Abstract:
A vehicular mirror includes a heater is mounted adjacent to the mirror and is preferably resizable to conform to a configuration of the mirror. A method of manufacturing a vehicular mirror assembly is provided as well. An exemplary mirror according to the invention has a housing with an opening, a heater and a mirror. The heater is resized to conform with the size of the mirror. The heather element is mounted within the housing adjacent to the mirror. The resizable nature of the heater element allows a commonly-sized heater element to be used in a wide variety of mirror configurations, shapes and sizes.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application Serial No. 60/319,398, filed on Jul. 15, 2002. 
     
    
     
       BACKGROUND OF INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    In one aspect, the invention relates to a heater for a vehicular mirror assembly including a heater element that is resizable to conform to the size and/or shape of a mirror in the vehicular mirror assembly. In another aspect, the invention relates to a method of manufacturing a vehicular mirror with a heater element including the steps of resizing the heater element and mounting the heater element to the mirror.  
           [0004]    2. Description of the Related Art  
           [0005]    External mirrors are ubiquitous for contemporary vehicles and have long been used to aid the driver in operating the vehicle, especially in improving the rearward view of the driver. A typical rearview mirror comprises a housing having an opening and a mirror element mounted in the housing in register with the opening in the housing for rearward reflective viewing. Over time, more and more functionality has been incorporated into the external mirror assemblies. For example, it has become common to mount a heater element adjacent to the mirror within the housing to aid in deicing, defrosting, and defogging operations on the mirror surface.  
           [0006]    The heater element has taken many forms over the years, but most recently as a “pad” which is mounted in planar alignment behind the mirror within the mirror housing. For example, ITW ChronoTherm has developed a heater pad for rear-view mirrors on passenger cars, trucks, and other vehicles that uses a proprietary material that is self-regulating in temperature control and allows for high wattage heating at sub-zero temperatures.  
           [0007]    While the performance of heater elements such as the example provided in the previous paragraph has been satisfactory, the time, cost, and complexity of manufacturing vehicular mirrors with these heating elements can be extensive and costly mainly due to the wide variety of configurations, shapes, and sizes of vehicular mirrors. For example, a computer-based thermal analysis program has been used in the past to analyze each mirror shape and to determine the power distribution necessary to provide the most even temperature distribution. In addition, since each mirror shape can be unique, the heater element must typically be customized for each mirror design to take into account performance specifications, heat transfer conditions, process capabilities, and production tolerances. Often, computer aided design (CAD) files must be generated for each mirror shape.  
         SUMMARY OF INVENTION  
         [0008]    In one of its aspects, the invention relates to a vehicular mirror comprising: a housing adapted to be mounted to a vehicle body, the housing having an opening therein; a mirror mounted within the housing and having a reflective surface in register with the opening in the housing; a mounting plate in register with the mirror; and a heater element mounted adjacent to the mirror to the mounting plate within the housing, the heater element being sizable to conform to a size of a selected one of a plurality of mirrors.  
           [0009]    In another of its aspects, the invention relates to a heater element for a vehicular mirror wherein: the heater element is selectively sizable to conform to a size of a selected one of a plurality of mirrors.  
           [0010]    Various embodiments are contemplated within the broad scope of this invention. The heater element can be sized to conform to the perimeter of the selected one of the plurality of mirrors. The heater element can be stretched to conform to the size of the selected one of the plurality of mirrors. The heater element can further comprise at least one row of spaced-apart penetrations and the penetrations form apertures when the heater element is stretched. The penetrations can be slits. The slits can be parallel to each other. The slits can be inclined relative to each other. The at least one row of spaced-apart penetrations can comprise at least two rows of spaced-apart penetrations. The penetrations in a first row of the at least two rows of spaced-apart penetrations can be spaced laterally from the penetrations in a second row of the at least two rows of spaced-apart penetrations. The heater element can be wrapped around at least one edge of the mounting plate.  
           [0011]    A bezel can be provided wherein the heater element is attached to the mounting plate by the bezel which applies a clamping force to the heater element where the heater element is wrapped around the at least one edge of the mounting plate. The heater element can further comprise a roll-formed seam along at least one edge wherein the heater element is attached to the mounting plate by the roll-formed seam which is retained against the mounting plate when the heater element is wrapped around the at least one edge of the mounting plate. The heater element can be an elliptical spiral and an end portion of the elliptical spiral can be removed to conform the heater element to the size of the selected one of the plurality of mirrors. The heater element can be an elliptical spiral and the elliptical spiral can be stretched to conform the heater element to the size of the selected one of the plurality of mirrors.  
           [0012]    In another aspect, the invention relates to a method of manufacturing a vehicular mirror assembly comprising a mirror housing having an opening, a heater element, a mounting plate, and a selected one of a plurality of various-sized mirrors, the method comprising the steps of: selectively sizing the heater element to conform with the size of the selected one of the plurality of various-sized mirrors; and mounting the heater element within the housing adjacent to the mirror.  
           [0013]    The method can further comprise the step of forming slits in the heater element. The slits can be parallel to each other. The slits can be inclined relative to each other. The method can further comprise the step of stretching the heater element to conform to the size of the selected one of the plurality of various-sized mirrors. The method can further comprise the step of wrapping the heater element around at least one edge of the mounting plate. The method can further comprise the step of attaching a bezel to the mounting plate after the heater element is wrapped around the at least one edge of the mounting plate so that the bezel applies a clamping force to the heater element where the heater element is wrapped around the at least one edge of the mounting plate. The method can further comprise the step of forming a roll-formed seam along at least one edge of the heater element. The method can further comprise the step of attaching the heater element to the mounting plate so that the heater element is attached to the mounting plate by the roll-formed seam which is retained against the mounting plate when the heater element is wrapped around the at least one edge of the mounting plate. The method can further comprise the step of forming the heater element as an elliptical spiral. The method can further comprise the step of removing an end portion of the elliptical spiral to conform the heater element to the size of the selected one of the plurality of mirrors. The method can further comprise the step of stretching the elliptical spiral to conform the heater element to the size of the selected one of the plurality of mirrors. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective view of a vehicular mirror assembly according to the invention.  
         [0015]    [0015]FIG. 2 is an exploded perspective view of the vehicular mirror assembly of FIG. 1 with a mirror removed to expose a resizable heater element according to the invention.  
         [0016]    [0016]FIG. 3 is a top plan view of the heater element of FIG. 2 in a sized configuration for the mirror assembly of FIG. 1.  
         [0017]    [0017]FIG. 4 is a top plan view of the heater element of FIG. 2 in an unsized configuration.  
         [0018]    [0018]FIG. 5 shows the unsized heater element of FIGS. 2-4 being stretched in a first direction.  
         [0019]    [0019]FIG. 6 shows the unsized heater element of FIGS. 2-4 being stretched in a second direction.  
         [0020]    [0020]FIG. 7 shows the unsized heater element of FIGS. 2-4 being stretched in the first and second directions generally simultaneously.  
         [0021]    [0021]FIG. 8 shows a first alternative embodiment of the heater element of FIGS. 2-7.  
         [0022]    [0022]FIG. 9 shows a second alternative embodiment of the heater element of FIGS. 2-7.  
         [0023]    [0023]FIG. 10 shows a mirror housing being sized to receive a sizeable mirror heating element according to the invention by way of determination of the major and minor axes of the mirror assembly.  
         [0024]    [0024]FIG. 11 shows the mirror housing of FIG. 10 receiving the heating element of FIG. 9.  
         [0025]    [0025]FIG. 12 shows a third alternative embodiment of the heater element of FIGS. 2-7.  
         [0026]    [0026]FIG. 13 shows a fourth alternative embodiment of the heater element of FIGS. 2-7 in an exploded configuration with a mirror element on which it is to be mounted.  
         [0027]    [0027]FIG. 14 is a cross-section taken along lines  14 - 14  of FIG. 13.  
         [0028]    [0028]FIG. 15 shows a fifth alternative embodiment of the heater element of FIGS. 2-7. 
     
    
     DETAILED DESCRIPTION  
       [0029]    Referring now to the drawings and to FIGS. 1-2 in particular, a vehicular mirror assembly  10  is shown comprising a housing  12  that is adapted to be mounted to a vehicle (not shown), such as by a mounting to a base  14 . A mirror  16  is mounted within the housing  12  in a conventional manner.  
         [0030]    It will be understood that the mirror assembly  10  shown and described herein is for illustrative purposes only and can take the form of any well-known mirror assembly. The mirror assembly  10  can also include various functional items including, but not limited to, a manually-or powered-folding device for pivoting the mirror housing relative to a vehicle, a manually- or powered-extension device for extending the mirror housing relative to a vehicle, and/or a manually- or powered-actuation device for pivoting the mirror relative to the mirror housing.  
         [0031]    As can be seen in FIG. 2, the mirror  16  is mounted to a mounting plate  18  with a heater element  20  therebetween. Although its configuration is not important to this invention, the mounting plate  18  is typically a planar member that is interconnected to the housing via a gimbal joint (not shown) on its forward-facing side to allow for pivotal movement of the mirror  16  with respect to the housing  12 . As is commonly-known in the art, the mounting plate  18  can also receive powered actuators for pivotally adjusting the mirror  16  relative to the housing  12  by way of a hand-switch carried onboard the vehicle (not shown) which effectuates pivotal adjustment of the mirror  16 .  
         [0032]    The heater element  20  is the focus of this invention and comprises a body  22 , generally planar in configuration, which is mounted between the mirror  16  and the mounting plate  18  within the mirror housing  12 . The body  22  of the heater element  20  has several apertures therein, shown by example by reference numeral  24  in FIG. 3.  
         [0033]    The heater element  20  is resizable so that the heater element  20  can be manufactured in a common size and stretched at the time of assembly to the mounting plate  18 . For example, an unsized configuration  20 ′ of the heater element  20  is shown in FIG. 4 comprising several penetrations or slits  24 ′ formed in the body  22  of the unsized sized heater element  20 ′. Preferably, the slits  24 ′ are arranged in a predetermined pattern to provide an optimal level of stretchability to the unsized heater element  20 ′, although any configuration and arrangement of the slits  24 ′ may be used without departing from the scope of this invention.  
         [0034]    For example, it has been found that the row-by-row off-set arrangement shown in FIG. 4 produces preferable results. In FIG. 4, it can be seen that the horizontal positioning of the slits  24 ′ in one row is out of phase with the horizontal positioning of the slits  24 ′ in immediately adjacent rows. In this manner, as the unsized heater element  20 ′ is stretched in the horizontal and vertical directions shown in FIG. 5, the slits  24 ′ form the apertures  24  as shown in FIG. 3 throughout the body  22  of the sized heater element  20  of FIG. 3. The offset arrangement of the slits  24 ′ aligns sufficiently large portions of the material making up the body  22  with ends of the slits  24 ′ to prevent tearing during resizing of the heater element  20 .  
         [0035]    [0035]FIGS. 6 and 7 show the unsized heater element  20 ′ of FIG. 4 being stretched only in a single direction, i.e., horizontally in FIG. 6 and vertically in FIG. 7. In addition, FIG. 8 shows an alternative arrangement of the slits  24 ′ in the body  22  of the unsized heater element  20 ′ for producing a different pattern of apertures  24  once the heater element is placed into a sized configuration (i.e., identified by reference numeral  20  in the example sized configuration in FIG. 3).  
         [0036]    In assembly, the unsized heater element  20 ′ as shown in FIG. 4 is stretched at the time of assembly to the mounting plate  18  into the larger configuration shown in FIG. 3 in which the slits  24 ′ are converted into the apertures  24  as a result of the resizing of the heater element from the unsized configuration  20 ′ (see FIG. 4) to the sized configuration  20  (see FIG. 3). The sized configuration of the heater element can be mounted to the mounting plate  18  in any conventional manner such as heat stakes  26  shown at each corner of the heater element  20  in FIG. 2. The heater element  20  is interconnected to a selectively actuated source of electricity to provide the power necessary to activate the heater element  20  during use to provide a source of heat to the mirror  16 .  
         [0037]    [0037]FIG. 9 shows a second alternative embodiment of the heater element of FIGS. 2-7. In this embodiment, the heater element  20  is provided as an elliptical configuration having a major and a minor axis as is conventionally known in the geometry of ellipses. More specifically, the embodiment of the heater element  20  in FIG. 9 is shown as a spiral member  30  increasing radially outwardly in expansion. With reference to FIG. 10, a major and a minor axis of a mirror housing  12  (and its associated mirror mounting plate  18 ) can be identified. Then, as shown in FIG. 11, the spiral member  30  of the heating element  20  shown in FIG. 9 can be “snipped” at a location so that the major and minor axes of the resulting elliptical configuration of the heater element  20  in FIG. 9 generally corresponds to the major and minor axes of the mounting plate  18  and, thus, the mirror element  16 . Of course, the spiral member  30  can be stretched as it is applied for greater coverage with respect to the mirror element  16 . In this manner, the spiral member  30  is sizeable to provide an optimal degree of coverage to the mounting plate  18 .  
         [0038]    [0038]FIG. 12 shows a third alternative embodiment of the heater element of FIGS. 2-7. In this manner, the heater element  20  of FIG. 12 is shown disposed between the mirror element  16  and the mounting plate  18  as previously described. However, in this embodiment, the heater element  20  is stretched across the face of the mounting plate  18  and wrapped around its periphery, a portion of which is shown in FIG. 12. A terminal end  32  of the heater element  20  is held in place by a bezel  34  which is shown as a C-shaped member with a first end  36  abutting a surface of the mirror element  16  and a second end  38  (shown with an optional serrated surface) pinching the periphery of the heater element  30  between the second end  38  of the bezel  34  and an underside of the mounting plate  18 .  
         [0039]    [0039]FIG. 13 shows a fourth alternative embodiment of the heater element of FIGS. 2-7 in an exploded configuration with a mirror element  16  and a mounting plate  18  on which it is to be mounted. The heater element  20  of FIG. 13 is configured as a stretchable swatch of material  40  formed with reverse roll-formed seams  42  on at least two edges thereof. In the cross-section shown in FIG. 14, the seams  42  are stretched around the periphery of the mounting plate  18  and are retained therebehind, preferably due to the elastic nature of the material making up the heater element  20  in this embodiment.  
         [0040]    [0040]FIG. 15 shows a fifth alternative embodiment of the heater element of FIGS. 2-7. In this embodiment, the heater element  20  is shown as a web  44  of material traveling along a first conveyor  48  which is aligned with a second conveyor  46  carrying pre-formed mounting plates  18 . The mounting plates  18  are delivered onto the web  44  from the conveyor  46  at which time the material making up the web  44  can be sized to the perimeter of the mounting plates  18  and separated from the web  44  to form the heater elements  20  for each of the mounting plates  18  in this process. The heater elements  20  can be affixed to the mounting plates  18  as previously described or through conventional means such as an adhesive, followed by attachment of the mirror  16  over the heater element  20 . Alternatively, the heater elements  20  can be die cut from the material making up the web  44  in preselected shapes to be later stretched to fit a selected mounting plate  18  for assembly between the mounting plate  18  and the mirror  16  as described herein.  
         [0041]    In any of the embodiments described herein, it will be understood that the material making up the heater element  20  can be any suitable material for delivering heat to the mirror element  16  and which is connected to a suitable power supply. The material making up the heater element  20  can include, but is not limited to: a conductive elastomer, a textile material (such as an open-weave gauze) having a carbon-based mesh material interweaved there-with, an elastomer with a carbon coating, an elastomeric material with a carbon material spray-coated thereon, a stretchable fabric material as a carrier with a sprayed-on conductive carbon ink, or a stretchable fabric with an applied adhesive (to aid bonding to the mounting plate  18 ) with an embedded carbon ink. It will be understood that other materials can also be employed without departing from the scope of this invention.  
         [0042]    It has thereby been found that, with a heater element configuration  20  as shown herein, a commonly-sized unsized heater configuration can be made which is not dependent upon the size of the particular mirror assembly components (i.e., the mounting plate  18 , the mirror  16 , etc.). Rather, a far smaller subset of sizes of heater elements  20  can be provided and the heater elements  20  can be sized to a predetermined width and height of the mounting plate  18  at the time of manufacture. In this way, the novel heater element described herein provides great flexibility and cost savings in the manufacture of mirror assemblies  10 .  
         [0043]    While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.