Abstract:
A window lift bracket for attachment to a mounting edge of a movable window and which is connectable to a window lifting mechanism. The window lift bracket includes a base which is attachable to the window lifting mechanism and spaced apart portions extending from the base being positionable on either side of the movable window. The spaced apart portions define a channel therebetween. The window lift bracket includes at least one member, such as a flexible beam member, which is disposed generally in the channel for engaging the window when the window is disposed therein. Preferably, the engagement between the member and the window provides a reduced stress area at the bottom of the channel. Opposing surfaces of the spaced apart portions may provide convoluted surfaces, such as protrusions and depressions, which effectively increase the surface area to which the adhesive adheres, thereby improving the adhesion of the adhesive to the window bracket and the window.

Description:
RELATED APPLICATION 
     This application claims the benefit of United States Provisional Application Serial No. 60/160,102, filed Oct. 18, 1999. 
    
    
     BACKGROUND 
     The present invention relates generally to a bracket for attachment to a movable window and connection to an automotive window lifting mechanism, and relates more specifically to a window bracket having at least one flexible beam which engages the window. 
     In vehicles, and especially automobiles, it is highly desirable to have movable windows. With reference to automobiles, windows are displaceable upwardly and downwardly relative to a door assembly by use of a manual crank or an electrically-driven window lifting mechanism. Many window lifting mechanisms include a scissoring linkage which transfers motion from a manual crank or electric drive to a window connected to the window lifting mechanism. The scissoring linkage is used in order to limit the movement of the window in a generally vertical direction. A cross member is attached to the scissoring linkage to provide a support for the movable window. Such a window lifting mechanism is disclosed in U.S. Pat. No. 5,513,468, which is hereby incorporated herein by reference in its entirety. 
     Mounting brackets or window lift brackets are often used to attach the movable window to the cross member attached to the scissoring linkage. These brackets generally are attached to a mounting edge of the window at two spaced apart locations and a portion of the bracket is attached to the window lifting cross member. 
     Many prior art brackets present problems in a movable window assembly, are difficult to manufacture, and are relatively expensive. Some prior art brackets are manufactured from a stamped strip of metal which is deformed to a specified bracket configuration. These deformed metal components are subject to damage and failure as the result of corrosion thereby providing a weak link in the movable window assembly. 
     With regard to the manufacturing of such prior art window lift brackets, many opportunities for complications and defects arise. Initially, a strip of metal is stamped or cut to a desired size. Next, the metal component is stamped, bored or drilled to provide through holes which will be used as described here and below. The stamped metal component is deformed to form a bracket having a generally “Y” shaped cross section. The deformed metal component must now be protected by painting, anodizing or other means to delay the corrosion process. Once protected, plastic mounted clips are positioned in a channel portion of the bracket and secured in the thru holes by use of a heat staking process. The base of the bracket is drilled for receiving a fastener which will be used to attach the bracket to the lift mechanism cross member. 
     In applying such prior art lift brackets to a window, an adhesive is disposed in the channel portion of the lift bracket and the lift bracket is attached to the mounted edge of a movable window. The window, with two or more brackets positioned thereon, is subjected to a heat curing process in order to cure the adhesive. A heat curing adhesive is used in order to properly adhere the adhesive to the surfaces of the bracket and window. 
     As may be understood from the description hereinabove, there are numerous opportunities for problems to arise in the manufacture of a window lift bracket as set forth by the prior art. For example, if the bracket is not properly formed, it may not properly fit on the window or function in the movable window assembly. In each step of the fabrication process a new operation, coating, or joining method is used, each presenting its own opportunity for problems. 
     For example, as mentioned, clips must be used with the deformed metal bracket in order to prevent the bracket from scratching the window glass and the protective coating on the window. The plastic clips are an individual piece part which must be designed, purchased, and managed in the manufacturing system. The clips are typically produced by selectively cutting an extruded plastic strip. Each clip must be cut to a generally precise dimension thereby requiring an additional inspection step. The clips must also be heat staked to the metal bracket. The heat staking process deforms a portion of the plastic clip over an abutting portion of the metal bracket. If the plastic portion is not properly melted, it may not be securely held to the metal bracket which could result in a release of the window from the bracket under certain circumstances. Clearly, it is not desirable to have a release of the window from the bracket. 
     Additionally, an adhesive is disposed in a channel portion of the metal bracket to secure the window to the bracket. The adhesive must be selected to attach or adhere to the metal bracket (or the protective surface of the metal bracket) and the window glass and/or coating. The numerous and diverse material properties involved can make selection of an appropriate adhesive somewhat difficult. Further, if the metal bracket begins to corrode, the corrosion could result in the adhesive detaching from the metal bracket. 
     As may be clear, there are numerous problems associated with the manufacture and use of metal window lift brackets as currently used in the prior art. As such, it is important to find a window lift bracket which will overcome the problems associated with the prior art devices. 
     A window lift bracket which overcomes many of the problems presented by some prior art window brackets can be found in U.S. Pat. No. 5,513,468, which has been incorporated herein in its entirety be reference hereinabove. The bracket which is disclosed in the &#39;468 patent is also generally illustrated in FIG. 1 of the present application, as is designated with reference numeral  10 . The bracket  10  includes a base  12  which is configured for attachment to a window lifting mechanism (see FIG. 1 of the &#39;468 patent), and spaced apart sidewalls  14  which extend from the base  12  and define a channel  16  which receives an edge of the window (see FIGS. 1,  6  and  7  of the &#39;468 patent). Each of the sidewalls  14  includes alternating protrusions  17  and depressions  18  which define a convoluted surface. 
     As described in the &#39;468 patent, the convoluted surfaces increase the effective surface area of the inside surface of the sidewalls  14 , thereby increasing the contact surface between an adhesive applied to the convoluted surfaces and the window which is disposed in the channel  16 . As disclosed in the &#39;468 patent, the bracket  10  also includes a groove  19  at the bottom of the channel  16  which provides even greater holding forces between the adhesive and the window. As disclosed in the &#39;468 patent, the bracket  10  is preferably formed of a plastics material which allows the bracket to be integrally formed as a unitary, single-piece body. Such a configuration presents certain advantages, including certain manufacturing advantages. 
     While the bracket  10  disclosed in the &#39;468 patent and illustrated in FIG. 1 of the present application presents several advantages over many prior art window brackets, the bracket  10  also presents a disadvantage. Specifically, the bracket  10  is configured such that when the window is installed in the bracket  10 , and specifically in the channel  19  defined by the sidewalls  14 , an interference fit results between the sidewalls  14  and the window. The interference fit tends to create high stresses in the bottom of the channel  16 , which may cause the bracket  10  to fail. 
     An embodiment of the present invention essentially provides an improvement to the bracket disclosed in the &#39;468 patent. Hence, the embodiment provides many of the same advantages as does the bracket disclosed in the &#39;468 patent, while being directed to overcome the noted disadvantage-namely, eliminating the high stress area which is present in the bottom of the channel of the bracket disclosed in the &#39;468 patent. 
     OBJECTS AND SUMMARY 
     A general object of an embodiment of the present invention is to provide a window lift bracket which will securely attach to a window and a window lifting mechanism. 
     Another object of an embodiment of the present invention is to provide a window lift bracket with a reduced stress area. 
     A still further object of the present invention is to provide a window lift bracket which is efficiently manufactured and eliminates numerous manufacturing steps and the parts required to manufacture a bracket. 
     Briefly, and in accordance with at least one of the foregoing, an embodiment of the present invention envisions a window lift bracket for attachment to a mounting edge of a movable window and which is connectable to a window lifting mechanism. The window lift bracket includes a base which is attachable to the window lifting mechanism and spaced apart portions extending from the base being positionable on either side of the movable window. The spaced apart portions define a channel therebetween. The window lift bracket includes at least one member, such as a flexible beam member, which is disposed generally in the channel for engaging the window when the window is disposed therein. Preferably, the engagement between the member and the window provides a reduced stress area at the bottom of the channel. Opposing surfaces of the spaced apart portions may provide convoluted surfaces, such as protrusions and depressions, which effectively increase the surface area to which the adhesive adheres, thereby improving the adhesion of the adhesive to the window bracket and the window. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an enlarged perspective view of a prior art window lift bracket, which is disclosed in U.S. Pat. No. 5,513,468; 
     FIG. 2 is an enlarged perspective view of a portion of a window lift bracket, where the window lift bracket is in accordance with an embodiment of the present invention; 
     FIG. 3 is a front elevational view of the window lift bracket shown in FIG. 2, showing the entire bracket; 
     FIG. 4 is a top plan view of the window lift bracket shown in FIG. 3; 
     FIG. 5 is a side elevational view of the window lift bracket shown in FIG. 3; 
     FIG. 6 is cross-sectional view of the window lift bracket shown in FIG. 3, taken along line  6 — 6  of FIG. 2; 
     FIG. 7 is a side elevational view similar to FIG. 5, but showing the window disposed in a channel defined by the bracket; 
     FIG. 8 is a cross-sectional view similar to FIG. 6, but showing a window disposed in the channel defined by the bracket; 
       5 FIG. 9 is an enlargement of a top portion of FIG. 8, showing an adhesive disposed in the channel defined by the bracket; and 
     FIG. 10 is an enlargement of a middle portion of FIG. 4, showing the window disposed in the channel defined by the bracket, and showing the engagement of two flexible beam members of the bracket with the window. 
    
    
     DESCRIPTION 
     While the invention may be susceptible to embodiment in different forms, there is shown in the drawings, and herein will be described in detail, an embodiment with the understanding that the present description is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to that as illustrated and described herein. 
     FIGS. 2-10 illustrate a window lift bracket  20  which is in accordance with an embodiment of the present invention. The window lift bracket  20  is similar to that which is disclosed in U.S. Pat. No. 5,513,468, which has been incorporated herein in its entirety be reference hereinabove. Like the bracket shown in FIG. 1 (and disclosed in the &#39;468 patent), the bracket  20  illustrated in FIGS. 2-10 is configured for attachment to a window lifting mechanism  24  and a window  26  (see FIG. 3, for example), essentially providing a link between the window lifting mechanism  24  and the window  26 . The bracket  20  illustrated in FIGS. 2-10 of the present application preferably includes a base  28  and spaced apart means, such as generally parallel sidewalls  30 , which extend from the base  28 , thereby defining a channel  32  which receives an edge  34  of the window  26 . Preferably, the spaced apart means  30  provide convoluted surfaces which provide increased surface areas for an adhesive  36  to bond. Unlike the bracket  10  shown in FIG. 1 (and disclosed in the &#39;468 patent), wherein an interference fit results between sidewalls  14  of the bracket  10  and the window when the window is disposed in the channel  16  between the sidewalls  14 , the bracket  20  illustrated in FIGS. 2-10 includes a plurality of flexible beam members  40  which extend from the base  28  and are disposed generally in the channel  32 . The flexible beam members  40  engage the window  26  when the window  26  is disposed in the channel  32 , and the engagement between the flexible beam members  40  and the window  26  works to localize resulting stress at the flexible beam members  40 , thereby reducing the stress which would otherwise be experienced at the bottom of the channel  32 , such as in the bracket  10  shown in FIG. 1 (and disclosed in the &#39;468 patent). All of this will be described more fully later herein. 
     As discussed above, preferably the window lift bracket  20  is configured to engage a window lifting mechanism  24 . Specifically, preferably the base  28  of the window lift bracket  20  includes one or more bores  42  for receiving corresponding fasteners  44  (shown in phantom in FIG. 3) which secure the base to the window lifting mechanism  24 , such as to a cross member of the window lifting mechanism  24 . While only a portion of the window lifting mechanism  24  is shown in FIG. 3, and the window lifting mechanism  24  is omitted from the rest of the FIGS. for clarity, a window lifting mechanism  24  which may be employed with the window lift bracket  20  is disclosed in U.S. Pat. No. 5,513,468 (see specifically FIG. 1 of the &#39;468 patent), and the &#39;468 patent has been incorporated herein in its entirety be reference hereinabove. 
     As discussed above, the window lift bracket  20  is configured to receive an edge  34  of a window  26  and effectively provides a link between the window lifting mechanism  24  and the window  26 . Preferably, the window lift bracket  20  is configured to be securely engaged with an edge  34  of the window  26 , without scratching the window or a protective coating which is often applied to windows. 
     As shown, the window lift bracket  20  includes spaced apart means  30  which are attached to and extend from the base  28  for attaching the bracket  20  to a window  26 . The spaced apart means  30  define a channel  32  therebetween in which the edge  34  of the window  26  is fitted Preferably, an inside surface  46  of the spaced apart means  30  provides a convoluted surface for adhesion to an adhesive  36 . 
     The spaced apart means  30  are preferably formed as generally upstanding, spaced-apart sidewalls  30  which are attached to and extend from the base  28 . Inside facing surfaces  46  of the sidewalls  30  preferably include protrusions  50  which are shaped as ridges, and corresponding depressions  52  which are shaped as troughs. Preferably, the ridges  50  and troughs  52  are generally parallel to the direction of travel of the window  26  (arrow  56  in FIG. 3 generally depicts a preferred direction of travel of the window  26 ). The ridges  50  and troughs  52  define a convoluted inside surface. The convoluted surfaces preferably increase the effective surface area of the inside surface  46  of the sidewalls  30 , thereby increasing the contact surface between an adhesive  36  which is applied to the convoluted surfaces and to the window  26 . 
     Preferably, the sidewalls  30  are spaced-apart such that when the window  26  is disposed in the channel  32 , a gap (identified by reference numeral  60  in FIG. 10) exists between the sidewalls  30  and the window  26 , and only the flexible beam members  40  contactably engage the window  26 . The flexible beam members  40  provide that the stress on the sidewalls  30  is localized on the flexible beam members  40 , and that the stress which would otherwise be experienced at the bottom of the channel  32  (i.e. proximate area  70  illustrated in FIG. 9) is reduced. 
     For example, the bracket  10  shown in FIG. 1 (and disclosed in the &#39;468 patent) is configured to provide an interference fit between the sidewalls  14  of the bracket  10  and a window disposed in the channel  16 . Such an interference fit provides a high stress area generally at the bottom of the channel (i.e. at area  15  shown in FIG.  1 ). 
     In contrast, the bracket  20  illustrated in FIGS. 2-10 includes flexible beam members  40  which engage the window  26 , and a gap  60  (see FIG. 10) is preferably provided between the inside surfaces  46  of the sidewalls  30  and the window  26 . Hence, the stresses are localized on the flexible beam members  40 , and a high stress area is eliminated from the bottom of the channel  32  (i.e. at area  70  identified in FIG.  9 ). As shown in FIGS. 2,  5 ,  6  and  9 , each of the flexible beam members  40  may include a hook portion  72  at an end  74  thereof, for contacting the window  26  which is disposed in the channel  32 . Preferably, the flexible beam members  40  are also configured to allow the free flow of adhesive  36  along the inside surfaces  46  of the sidewalls  30 , and the adhesive  36  does not leak from the bracket  20 . 
     As shown in FIG. 9, the adhesive  36  is preferably disposed in the channel  32  for contact between the inside surfaces  46  of the sidewalls  30  and the window  26 . Preferably, the adhesive  36  is retained between the sidewalls  30  and the window  26 , and the convoluted surfaces provide increased surface area for improved adhesion. As shown, the adhesive  36  is also disposed between the spaced apart sidewalls  30  and the flexible beam members  40 . 
     In order to provide even greater holding forces between the adhesive  36 , the bracket  20  and the window  26 , a groove  80  may be formed in the bracket  20  generally at the bottom of the channel  32 , between the sidewalls  30  for receiving the adhesive  36  therein. Preferably, the groove  80  generally runs the length of the bracket  20  to provide additional holding forces between the surface of the bracket  20  positioned proximate to the groove  80 , the adhesive  36  retained within the groove  80 , and the edge  34  of the window  26 . 
     One type of adhesive which is used in the attachment of the present bracket  20  to a window  26  requires a heat curing process. As such, the adhesive  36  is applied between the window  26  and the bracket  20  forming bonds between the window  26  and the inside surfaces  46  of the sidewalls  30  and the groove  80 . The window  26  and one or more attached window lift brackets define a movable window assembly which is subjected to a heated environment to cure the adhesive  36 . In this regard, it is preferable to form the bracket  20  of a suitable plastics material which can withstand the temperature range required for heat curing the adhesive  36 . 
     The bracket  20  is preferably formed of a plastics material which allows the bracket  20  to be integrally formed as unitary single piece body. A material such as injection molded glass filled nylon plastic may be used. Such material will provide the manufacturing benefits of plastic without compromising, and perhaps improving, the structural characteristics of the bracket  20 . 
     Unitary forming of the bracket  20  eliminates numerous manufacturing steps and, perhaps, inspection steps required in some prior art brackets. Further, forming the bracket  20  of plastic eliminates the need for individually manufactured and assembled clips to prevent scratching the glass and protective coating of the window. As discussed above, the bracket  20  is preferably configured to be attached to a cross member of a window lifting mechanism  24  by one or more fasteners  44  which extend through bores  42  formed in the base  28  of the bracket  20 . Use of fasteners  44  to attach the bracket  20  to the window lifting mechanism  24  helps to simplify the installation process and further reduces the weight of the overall vehicle assembly. 
     Preferably, the plastics material used in forming the bracket  20  will no t corrode, thereby eliminating corrosion failure which may occur in some prior art metal brackets. Additionally, providing that the bracket  20  is plastic eliminates the need for additional manufacturing steps such as coating of a metal bracket to delay the corrosion process. The plastics material greatly reduces the weight of the bracket  20  which may provide a noticeable cumulative effect since two brackets are often used per window which result in the use of eight brackets per vehicle thereby providing eight times the weight reduction per vehicle when comparing the plastic bracket to a prior art metal bracket. 
     While a preferred embodiment of the present invention is shown and described, it is envisioned that those skilled in the art may devise various modifications of the present invention without departing from the spirit and scope of the appended claims. The invention is not intended to be limited by the foregoing disclosure.