Patent Publication Number: US-2007101653-A1

Title: Hinge assembly for casement windows

Description:
FIELD OF THE INVENTION  
      The invention relates to an improved casement window, and in particular to a casement window hinge assembly having structure to reduce sash sag.  
     BACKGROUND OF THE INVENTION  
      Casement windows assemblies are well known in the art and described in, for example, U.S. Pat. No. 3,845,585 to Cecil, entitled “Casement Window,” and U.S. Pat. No. 4,254,583 to Smits et al., entitled “Window Unit,” which are both hereby incorporated by reference herein. In general, a casement window includes a window sash comprised of a sheet of glass surrounded by wood, vinyl or metal structure. A casement window has the sash hinged to one side in comparison to windows where the sash slides within the frame. The window sash engages the window frame though an upper and lower hinge assembly. The casement window sash swings on a hinge within the window frame along a vertical axis. Typically a crank mechanism is attached to the lower hinge for selectively opening and closing the window sash. Proper performance of the casement window requires that the window sash be properly aligned within the window frame.  
      One of the more common issues regarding casement windows is sash sag, which occurs when the sash portion of the window is out of square with the window frame. Sash sag can result from movement during installation, improper hinge positioning by the window manufacturer, settling of the building, warpage of the window or from external contact with the window sash in the open position. A window with sash sag will not properly seal. As a result the window is less effective in preventing moisture from coming in to the structure as well as increasing energy costs for heating and cooling of the building. Moreover, the improper seal may allow moisture into the window frame itself, which can lead to rotting of the window frame and the structure.  
      Correction of sash sag requires realigning the hinge so that the sash sits properly within the window frame. On some windows this requires disassembly of the hinge, which is labor intensive and costly. In the alternative, sash sag may be corrected with an adjustable hinge mechanism. An example of an adjustable mechanism designed to alleviate sash sag is disclosed in U.S. Patent Re. 34,657 (&#39;657 reissue) to La See, entitled “Cam Adjustment Device For Casement Window Unit,” which is hereby incorporated by reference herein. More specifically, the &#39;657 reissue discloses an index cam comprising a series of serrations that can engage a plurality of serrations on the track of the hinge assembly, which permits the cam to move relative to the track and facilitates adjustment of a link connected to a casement window sash. However, the engagement of the serrations on the cam with corresponding serrations on the track only permits predetermined, or defined, movements of the cam within the track. Additionally, the detailed structure of the cam and the track can increase manufacturing costs and make it make difficult to adjust the window sash once the hinge assembly has been installed.  
      With the number of residential casement windows being installed in new and existing homes, it would be desirable to provide a hinge assembly that can reduce or eliminate sash sag and overcome the limitations mentioned above. What is still needed is an adjustable hinge assembly that can be easily adjusted without disassembly of the casement window to reduce and/or eliminate sash sag, and that can be manufactured at a lower cost relative to existing hinge assemblies.  
     SUMMARY OF THE INVENTION  
      The hinge assembly of the present invention addresses the above-mentioned needs by providing a mechanism that can be adjusted to compensate for sash sag without requiring disassembly of the casement window assembly. Additionally, the hinge assemblies of the present disclosure do not comprise locking structures and therefore can be manufactured at lower costs relative to existing hinges.  
      In a first embodiment, the improved hinge assembly includes a track having an upwardly struck cam engaging portion defining a tri-lobular aperture, a first elongated arm or sash arm pivotably coupled to a slide on the track assembly, and a second elongated arm or support arm pivotably coupled to the track assembly and to the first elongated arm. The improved hinge further includes a cam member operably coupling the second elongated arm and the track. The cam member has a bi-lobular cam portion adapted to engage the cam engaging structure of the track such that the cam portion is selectively shiftable within the cam engaging structure. Shifting the cam portion within the cam engaging structure facilitates positional adjustment of the second elongated arm, and the attached window sash, which can reduce and/or eliminate sash sag. The cam engaging structure can be a tri-lobed aperture, while the cam portion can comprise an oval shape, an elliptical shape or the like. In embodiments where the aperture engaging portion is a bi-lobular, generally oval shaped cam, the cam portion can allow the cam member to be shifted up to about thirty-five degrees longitudinally in either direction from a center position within the tri-lobular aperture.  
      Due to the structure of the cam engaging structure and the cam portion, the second elongated arm and the attached window sash can be adjusted relative to the track such that sash sag can be reduced and/or eliminated. In some embodiments, the cam portion is biased against the track with a retainer, thereby creating friction for resisting movement of the cam portion within the cam engaging structure. This friction enables the adjustable cam to maintain position without the use of locking structures such as protrusions, serrations or the like, which in turn enables finer adjustment of the second elongated arm. Moreover, since the cam portion and the cam engaging structure do not comprise locking structures such as protrusions or serrations, the hinges of the present disclosure can be manufactured at a lower cost than hinges having locking structures and the like. The structure of the cam portion, along with the cam engaging structure, can also facilitate adjustment of the second elongated arm, and the attached window sash, without disassembling the sash from the hinge assembly.  
      In a first aspect, the invention pertains to a hinge for use with casement window assemblies having a track with a cam engaging portion defining a tri-lobed aperture, a first elongated arm pivotably coupled to a slide on the track, and a second elongated arm pivotably coupled to the track and to the first elongated arm. In these embodiments, the cam member is operably coupled to the second elongated arm and has an oval bi-lobular engaging portion positioned within the tri-lobed aperture, wherein the oval engaging portion is selectively shiftable in the tri-lobed aperture.  
      In a second aspect, the invention pertains to a cam for use in a hinge assembly, the cam including a body portion having a first end and a second end, an oval engaging portion oriented towards the first end, and a link engaging stud portion oriented towards the second end. In these embodiments, the oval engaging portion can be adapted to engage with and move within a corresponding aperture in a track such that the cam member can be selectively shifted up to about thirty-five degrees longitudinally in either direction from a center position within the aperture.  
      In a third aspect, the invention pertains to a method of reducing sash sag, the method including adjusting an elongated arm connected to a cam member having an oval engaging portion, wherein the oval engaging portion is positioned within a tri-lobed aperture of a track. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       FIG. 1  is a perspective view of a casement window assembly;  
       FIG. 2  is a plan view of a hinge assembly of the present disclosure, wherein the hinge is depicted in the open position;  
       FIG. 3  is a top plan view of the track of the hinge assembly of the present disclosure;  
       FIG. 4  is a side plan view of the track of  FIG. 3 ;  
       FIG. 5  is a cross-sectional view of the hinge assembly of  FIG. 2  depicting the tri-lobed aperture and a cam member positioned within the tri-lobed aperture;  
       FIG. 6  is a perspective view of a cam member depicting an oval engaging portion that can engage a tri-lobed aperture;  
       FIG. 7  is a plan view of a cam member having an oval engaging portion positioned within a tri-lobed aperture, wherein the oval engaging portion is centered within the tri-lobed aperture;  
       FIG. 8  is a plan view of a cam member having an oval engaging portion positioned within a tri-lobular aperture, wherein the oval engaging portion is shifted to the maximum travel limit in one direction;  
       FIG. 9   a  is a side view of an embodiment of a cam member having a bullet shaped engagement portion;  
       FIG. 9   b  is a top view of the cam member of  FIG. 9   a;    
       FIG. 9   c  is a bottom view of the cam member of  FIG. 9   a;    
       FIG. 10   a  is a plan view of an alternate embodiment of a hinge assembly according to the invention;  
       FIG. 10   b  is an enlarged view of a portion of the plan view of  FIG. 10   a  depicting the generally tri-lobular aperture;  
       FIG. 10   c  is a perspective view of the cam member of  FIG. 9   a;    
       FIG. 10   d  is a plan view of the cam member of  FIG. 9   a  engaged in the track aperture, wherein the cam member is centered within the aperture;  
       FIG. 10   e  is a plan view of the cam member of  FIG. 9   a  engaged in the track aperture, wherein the cam member is shifted to the limit of travel in one direction within the aperture; and  
       FIG. 10   f  is a cross sectional view of the cam member and track taken along section  10   f - 10   f  of  FIG. 10   e.   
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The present invention is an adjustable cam unit disposed within a casement window hinge for alleviating sash sag. As depicted in  FIG. 1 , a conventional residential casement window assembly  10  generally includes a window frame  11  with a window sash  15  hinged therein on upper and lower hinge assemblies  20   a ,  20   b . Window frame  11  has two vertical frame members  12   a ,  12   b , an upper horizontal frame  13 , and a lower horizontal frame  14 . Window sash  15  generally includes an upper horizontal member  16 , a lower horizontal member  17 , vertical frame members  18   a ,  18   b  and a glass panel  19 . In general, window sash  15  is sized to closely fit within window frame  11  in order to seal out moisture and maintain the environment within the structure.  
      Upper and lower hinge assemblies  20   a ,  20   b , which facilitate hingably mounting the window sash  15  to the window frame  11 . The hinge assemblies  20   a ,  20   b  generally include a track  22  mounted to the window frame  11 , a sash arm  23  coupled to the window sash  15  with one end longitudinally slidable on track  22 , and a support arm  24  pivotally coupled on a first end to track  22  and to sash arm  23  at the opposing end. In operation, window sash  15  pivots in and out of frame  11  on hinge assemblies  20   a ,  20   b  by rotating crank mechanism  26 . While the present description generally refers to casement windows, the present invention could be used with other types of window hinges including awning style windows.  
      Referring to  FIG. 2 , an embodiment of hinge assembly  25  according to the invention is depicted. Hinge assembly  25  generally includes track  22 , sash arm  23 , support arm  24  mounted at a first end to track  22  by adjustable cam  29  and at an opposing end to sash arm  23 . Track  22  includes multiple anchoring holes  26  for mounting to window frame  11  with screws, nails or other suitable fasteners. Sash arm  23  includes multiple anchoring holes  26  for mounting to window sash  15  with screws, nails or other suitable fasteners.  
      Track  22  is operably connected to sash arm  23  through a slide block  27 . Slide block  27  includes a pivotable connection  28  to sash arm  23  that allows for rotation of the sash arm  23  about the vertical axis. Slide block  27  is longitudinally slidable on track  22  so that the sash arm connection  28  may move longitudinally along track  22 . Track  22  is also operably connected to support arm  24  through adjustable cam  29  that enables rotation about the vertical axis as well as selective longitudinal movement. Opposing end of support arm  24  is mounted to a pivotable intermediate link  30  of sash arm  24  that allows for rotation about a vertical axis.  
      As depicted in  FIGS. 3-5 , track  22  includes flange  31  extending the length of track  22 . Flange  31  defines a lip portion  33  for guiding and locating slide block  27 . The slide block  27  engages lip portion  33  of track  22  to permit longitudinal sliding movement along track  22  as sash arm  23  pivots during operation of hinge assembly  25 . Track  22  has raised cam platform  34  defining pocket  35  between window frame  11  and track  22 . In some embodiments, the side portions of raised cam platform  34  may be sloped from about 40 degrees to about 75 degrees relative to lower horizontal frame  14  of window frame  11 . Pocket  35  allows for fastening of adjustable cam  29  to the underside or window frame side of track  22  as further described hereinbelow. A cam engaging structure  32   a  in the form of aperture  32  is defined in raised cam platform  34 . It will be appreciated that in other embodiments, cam engaging structure  32   a  need not be an aperture extending through track  22 , but may be a pocket or other similar structure for receiving a cam.  
      As depicted in  FIGS. 5-6 , adjustable cam  29  generally includes cam body  29   a , retainer  29   b , and keeper  41 . Cam body  29   a  presents first end  36  and second end  37  and is substantially symmetrical with respect to axis B-B. Link engaging stud portion  38  is oriented towards first end  37  and aperture-engaging portion  39  is oriented towards second end  37 . Link engaging stud portion  38  defines groove  40  for receiving keeper  41  to pivotably secure support arm  24  to adjustable cam  29 . In some embodiments, keeper  41  may be an o-ring composed of metal, plastic, rubber or combinations thereof. As depicted in  FIG. 6 , keeper  41  is received in groove  40  to retain support arm  24  on link engaging stud portion  38 . Additionally, cam body  29   a  includes guide plate portion  42  positioned between link engaging stud portion  38  and aperture engaging portion  37 . Guide plate portion  42  is dimensioned so as to be larger than aperture  32 , thereby preventing adjustable cam  29  from being drawn therethrough. Further, guide plate portion  42  may serve as a seat for guiding and supporting support arm  24 .  
      Aperture engaging portion  39  generally includes post  43  and cam  44 , both of which are substantially concentric with respect to axis B-B. In an embodiment of the invention, cam  44  may be generally oval shaped as depicted in  FIGS. 6-8  so as to conform with the edges  44   a  of a tri-lobular aperture  32 . Cam  44  and aperture  32  are coordinatingly dimensioned so that cam  44  is rotatably shiftable in aperture  32  about either or both vertical axes denoted A-A in the figures. It will be appreciated that, in other embodiments, cam  44  may have an elliptical shape or other shape enabling controlled rotational shifting within aperture  32 . One of ordinary skill in the art will recognize that no particular shape for cam  44  is required by the present disclosure. Rather, the shape of cam  44  is guided by the shape of the particular corresponding aperture  32  employed in a particular hinge assembly.  
      Retainer  29   b  is received on post  43  so as to retain adjustable cam  29  within aperture  32  on track  22 . In an embodiment, retainer  29   b  may be a metal ring interference fit onto post  43  so as to clamp track  22  between retainer  29   b  and guide plate portion  42 . In other embodiments, retainer  29   b  may be an O-ring, split ring, or the like, made from metal, plastic, rubber or combinations thereof. Retainer  29   b  and post  43  are received in pocket  35  so that track  22  may be mounted flush to window frame  15 .  
      The operation of adjustable cam  29  is depicted in  FIGS. 7 and 8 . In the depicted embodiment, aperture  32  is a tri-lobular non-circular opening adapted to engage corresponding structure on adjustable cam  29 . As described above, cam  44  is generally oval shaped to conform with edges  44   a  of aperture  32 . Cam  44 , as depicted in  FIGS. 7-8 , contacts track  22  at the endpoints  46 ,  47  of the major axis  48 . Cam  44  is rotatably shiftable within aperture  32  about either or both of endpoints  46 ,  47 , which coincide with axes A-A. By rotating adjustable cam  29 , axis B-B and post  37  which is concentric therewith, moves relative to the window frame  11  to shift the pivot point at which support arm  24  is pivotably connected with track  22 , thereby slightly shifting the position of window sash  15  relative to window frame  11 . Adjustable cam  29  is held in the adjusted position solely by the frictional forces between adjustable cam  29  and track  22  resulting from the clamping force applied to track  22  by retainer  29   b  and guide plate portion  42 . Significantly, there are no discrete structures such as serrations, or protrusions on either adjustable cam  29  or aperture  32  for mechanically locking the device in a position.  
      Referring to  FIG. 7 , cam  44  is centered in tri-lobular aperture  32 . From this position, cam  44  can be shifted in either direction about endpoint  47 , which facilitates shifting adjustable cam  29  and the attached support arm  24  relative to track  22 . Referring to  FIG. 8 , adjustable cam  29  and cam portion  44  are depicted as being shifted to the maximum travel limit within tri-lobular aperture  32 . Preferably, cam  44  and aperture  32  are dimensioned so as to enable up to about 35 degrees of rotation in either direction about endpoint  47  when cam  44  is centered in tri-lobular aperture  32  as depicted in  FIG. 7 .  
      An alternative embodiment is depicted in  FIGS. 9   a - c  and  10   a - e  for the adjustable cam. In the depicted embodiment, alternate aperture  132  has a “kernel-shaped” configuration. Adjustable cam  129  generally includes cam body  129   a , retainer  129   b , and keeper  141 . Cam body  129   a  presents first end  136  and second end  137  and is substantially symmetrical with respect to axis B-B. Link engaging stud portion  138  is oriented towards first end  136  and aperture-engaging portion  139  is oriented towards second end  137 . Link engaging stud portion  138  defines groove  140  for receiving keeper  141  to pivotably secure support arm  124  to adjustable cam  129 . In some embodiments, keeper  141  may be an o-ring composed of metal, plastic, rubber or combinations thereof. Keeper  141  is received in groove  140  to retain support arm  24  on link engaging stud portion  138 . Additionally, cam body  129   a  includes guide plate portion  142  positioned between link engaging stud portion  138  and aperture engaging portion  137 . Guide plate portion  142  is dimensioned so as to be larger than aperture  132 , thereby preventing adjustable cam  129  from being drawn therethrough. Further, guide plate portion  142  may serve as a seat for guiding and supporting support arm  24 .  
      Aperture engaging portion  139  generally includes post  143  and cam  144 , both of which are substantially concentric with respect to axis B-B. Cam  144  has a pair of opposing lobes  150 , each presenting opposing aperture contact surfaces  152 . As depicted, aperture contact surfaces  152  may be slightly concave between post  143  and lobe ends  154 . Cam  144  and aperture  132  are coordinatingly dimensioned so that cam  144  is rotatably shiftable in aperture  132  about the vertical axis denoted C-C in the figures.  
      Retainer  129   b  is received on post  143  so as to retain adjustable cam  129  within aperture  132  on track  122  as before. Again, retainer  129   b  may be a metal ring interference fit onto post  143  so as to clamp track  22  between retainer  129   b  and guide plate portion  142 . In other embodiments, retainer  129   b  may be an O-ring, split ring, or the like, made from metal, plastic, rubber or combinations thereof. Retainer  129   b  and post  143  are received in pocket  35  so that track  22  may be mounted flush to window frame  15 .  
      In some embodiments, post  143  may have a generally cylindrical portion  145  and may be chamfered at end  137  to form a generally frusto-conical end on post  143 . Cam portion  144  is disposed between post  143  and arm support portion  142 . Cam portion  144  is sized to allow for movement about the vertical axis within aperture  132 .  
      The assembled configuration and operation of adjustable cam  129  is depicted in  FIGS. 10   d  and  10   e . “Kernel-shaped” aperture  132  is again a generally tri-lobular opening, but adjacent sides  156  are shaped correspondingly with aperture contact surfaces  152  of cam  144 , while third side  158  is generally arcuate. Cam  144  is received in aperture  132 , contacting track  22  at endpoints  146 ,  147  of major axis  148 . Cam  144  is rotatably shiftable within aperture  132  about endpoint  147 , which coincides with axis C-C. By rotating adjustable cam  129 , axis B-B, and post  137  which is concentric therewith, moves relative to the window frame  11  to shift the pivot point at which support arm  24  is pivotably connected with track  22 , thereby slightly shifting the position of window sash  15  relative to window frame  11 . Adjustable cam  129  is held in the adjusted position solely by the frictional forces between adjustable cam  129  and track  22  resulting from the clamping force applied to track  22  by retainer  129   b  and guide plate portion  142 . Again, there are no discrete structures such as serrations, or protrusions on either adjustable cam  129  or aperture  132  for mechanically locking the device in a position.  
      Referring to  FIG. 10   d , cam  144  is centered in aperture  132 . From this position, cam  144  can be shifted in either direction about endpoint  147 , which facilitates shifting adjustable cam  129  and the attached support arm  24  relative to track  22 . Referring to  FIG. 10   e , adjustable cam  129  and cam  144  are depicted as being shifted to the maximum travel limit within aperture  132 . Preferably, cam  144  and aperture  132  are dimensioned so as to enable up to about 35 degrees of rotation in either direction about endpoint  147  when cam  144  is centered in aperture  132  as depicted in  FIG. 10   d.    
      The embodiments above are intended to be illustrative and not limiting. One of ordinary skill in the art will recognize that the above description is only one type of hinge assembly, and that the cam and track structures described below can be used with other types of hinges such as, for example, hinges where the sash arm has a fixed pivot axis relative to the track and the support arm is pivotably coupled to a moveable shoe. Although the present invention has been described with reference to particular embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.