Abstract:
Latch mechanisms for a slidable window generally disposed about the center of mass of a window pane on an edge perpendicular to its travel path to provide a straight line-pull using minimal mechanical effort and to provide a plurality of latch points to selectively secure a window pane in place along its travel path. Preferred embodiment provides a latch assembly for a window having first and second parallel edges slidably disposed between parallel first and second guiderails of a frame and can have a housing attached to a third window edge perpendicular to the first and second parallel sides, a latch handle connected to a drive gear engaged to a locking element slidably disposed within a channel of a housing in response to rotation of the drive gear about a pivot; the locking element movable from a biased extended position to a retracted position in response to rotation of the drive gear by a force sufficient to overcome the bias; and the first guiderail having a plurality of recesses spaced along the window travel path to receive the first end of the locking element in the operational position.

Description:
FIELD 
     The present mechanisms and methods generally relate to window systems, and specifically to latch mechanisms for slidable windows. 
     BACKGROUND 
     Work vehicles, such as tractors, combines, front-end loaders, excavators, and the like, typically have enclosed cabs with large window assemblies to provide ventilation and to allow an operator a good view of their work environment. Frequently, these window assemblies provide multiple fixed and/or movable window panes within a perimeter frame. 
     In the art, during vehicle assembly, a window assembly can be attached to a body side wall as a single complete unit or in pieces. In most instances the window assembly is permanently attached from the outside of the vehicle by its perimeter frame with a weatherproof seal using compressible sealing rings, adhesives, and the like. Protective caging can also be added to the outside surface of the window assembly to protect window panes and the vehicle operator from stray impact. 
     Often these types of window assemblies have at least one slidable panel, such as a slidable window pane. Given the sometimes extreme work environment to which these window assemblies are exposed, it is desirable to secure the window pane from unintended travel along its path. Therefore, latch mechanisms associated with the slidable aspect of a window pane should provide a simple and rugged design to not only facilitate ease of movement of the window pane, but also to provide a means to secure the window in place at a plurality of positions along its travel path. 
     Known in the art are latching mechanisms for slidable windows that attach to a window pane corner or corners. For example, the latching mechanism can restrict window pane movement through the use of a locking pin on the latching mechanism that can selectively engage any one of a plurality of locking pin openings within a window assembly frame along its travel path. In one embodiment, the latching mechanism can be disengaged by squeezing two lever elements together to withdraw the locking pin from the window assembly frame. Other embodiments can provide two corner latching mechanisms that can require a user to simultaneously slide spring loaded locking pins out of the window frame. These types of mechanisms are common on windows with vertical travel paths. 
     Unfortunately, latching mechanisms positioned on a window pane corner can be difficult to operate (such as when a user is wearing gloves). Also, the window may bind during attempted travel. For example, this racking condition can occur when a user grabs the latching mechanism to unlatch the locking pin and push or pull the window to a new position. Specifically, the reactive moment causes a rotational value instead of a straight line pull. Overcoming the rotational effects of a corner pull may require an operator to use both hands to complete window movement. The same is true for dual latching mechanism on two corners of the same window pane. 
     Attempts to overcome the shortcomings of the rotational effect to a window as it travels along its path can provide a simple latching mechanism on or about the center of a window pane edge perpendicular to its travel path (e.g., along a vertical axis of a horizontally sliding window pane). See generally, U.S. Pat. No. 7,036,851 to Romig and EP 1 700 979 B1 to Jurgen et al. These solutions are not complete though in that it typically only retains movement of the window pane in its closed position and/or provides a complicated mechanism which may be a maintenance issue for window assemblies in harsh working environments. Thus, despite the advances of the current state of the art, further improvements in window latch mechanisms for slidable windows are possible and desired. 
     SUMMARY 
     Accordingly, there is provided herein latch mechanism embodiments for a slidable window that overcomes the noted deficiencies in the art. Specifically, the present embodiments provide latch mechanisms for a slidable window generally disposed about the center of mass of a window pane on an edge perpendicular to its travel path. The present embodiments provide a balanced straight line pull using minimal mechanical effort and to provide a plurality of latch points to selectively secure a window pane in place along its travel path. 
     A preferred embodiment provides a latch assembly for a window having first and second parallel edges slidably disposed between parallel first and second guiderails of a frame and can have a housing attached to a third window edge perpendicular to the first and second parallel sides, a latch handle connected to a drive gear engaged to a locking element slidably disposed within a channel of a housing in response to rotation of the drive gear about a pivot; the locking element movable from a biased extended position to a retracted position in response to rotation of the drive gear by a force sufficient to overcome the bias; and the first guiderail having a plurality of recesses spaced along the window travel path to receive the first end of the locking element in the operational position. 
     In some embodiments, the bias can be achieved by a compression spring, a coil spring, rubber, or an elastic polymer applying a compressive force to a second end of the locking element. 
     In some embodiments, the latch handle can be a single lever having an orientation angle of about 25 to 45 degrees from the axis of the third window edge in an operating position. 
     Optional features can include a plurality of view holes adjacent to the plurality of recesses spaced along the window travel. The locking element can also be a wire-wound non-compressible cable. 
     Preferably, the latch handle is positioned to correspond to the center of mass along the third edge of the window, whereby a balanced pull-line is achieved. 
     In another embodiment, a second locking element can be provided to mirror the first locking element in an opposite direction from a biased extended position to a retracted position in response to rotation of the drive gear by a force sufficient to overcome the bias; and the second guiderail having a plurality of recesses spaced along the window travel path to receive the first end of the second locking element in the operational position. 
     Other preferred embodiments provide a window assembly that can have a window having first and second parallel edges slidably disposed between parallel first and second guiderails of a frame; a latch assembly having a housing attached to a window edge perpendicular to the first and second parallel sides, the latch assembly having a latch handle connected to a drive gear engaged to a locking element slidably disposed within a channel of a housing in response to rotation of the drive gear about a pivot; the locking element movable from a biased extended position to a retracted position in response to rotation of the drive gear by a force sufficient to overcome the bias; and the first guiderail having a plurality of recesses spaced along the window travel path to receive the first end of the locking element in the operational position. The guiderails can be horizontal. 
     Other features will become more apparent to persons having ordinary skill in the art to which pertains from the following description and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing features, as well as other features, will become apparent with reference to the description and Figures below, in which like numerals represent elements, and in which: 
         FIG. 1  is a perspective view of a window assembly having a latch mechanism for a sliding window according to the present embodiments. 
         FIG. 2  is a cutaway view of a latch mechanism for a sliding window according to the present embodiments in a latched ( 2 A) and unlatched ( 2 B) position. 
         FIG. 3  is a side view of a window assembly having a latch mechanism for a sliding window according to the present embodiments. 
         FIG. 4  is an end view of a window assembly having a latch mechanism for a sliding window according to the present embodiments. 
         FIG. 5  is a side view of a window assembly having a latch mechanism for a sliding window according to the present embodiments in various latched positions. 
         FIG. 6  is an exploded perspective view of a window assembly having a latch mechanism for a sliding window according to the present embodiments. 
         FIG. 7  is a sectional view of a window assembly latching mechanism according to the present embodiments taken along section lines A-A in  FIG. 3  in an operational mode. 
         FIG. 8  is a sectional view of a window assembly latching mechanism according to the present embodiments taken along section lines B-B in  FIG. 3  in an unlatched mode. 
         FIG. 9  is a side view of a latch mechanism for a sliding window according to the present embodiments in a latched position. 
         FIG. 10  is a side view of a latch mechanism for a sliding window according to the present embodiments in an unlatched position. 
         FIG. 11  is a sectional view of a window assembly latching mechanism according to the present embodiments taken along section lines C-C in  FIG. 9  in an operational mode. 
         FIG. 12  is a sectional view of a window assembly latching mechanism according to the present embodiments taken along section lines D-D in  FIG. 10  in an unlatched mode. 
     
    
    
     DETAILED DESCRIPTION 
     The present embodiments provide latch mechanisms for a slidable window generally disposed about the center of mass of a window pane on an edge perpendicular to its travel path. The present embodiments provide a balanced straight line pull using minimal mechanical effort and to provide a plurality of latch points to selectively secure a window pane in place along its travel path. 
     The present embodiments provide easy travel and easy latching/unlatching of a slidable window unit, which has multiple latching points along its path of travel. The mechanisms are simple to manufacture, easy to maintain and easy to operate. Although the illustrated embodiments are described for a horizontally slidable window assembly for a work vehicle, it is noted that many other applications and embodiments are possible within the scope of its elements, including vertically slidable window panes. Further, for ease of understanding the present embodiments, only one latch pin is illustrated, though dual latching pins travelling to opposite ends of a window pane are also possible. 
     In one embodiment, a pull and engage/disengage feature is centered on a generally square window pane. The preferred point of the pull and engage/disengage feature is on a window pane edge that is perpendicular to its travel path, and specifically at a location on the edge that is centered to the center of mass of the window pane. Factors that can alter direct center placement of the pull and engage/disengage feature can include the geometry of the window (which alters the location of the center of mass) and the coefficient of friction of the window pane against its upper and lower seals. As such, the present embodiments preferably provide a straight line pull to eliminate a racking condition while the window pane slides. This can allow one handed operation. Reduction and/or elimination of the racking condition allows longer life of the window seals, thus reducing maintenance costs and vehicle down time. 
     Ease of use can further be improved through the use of a window latch lever that is easy to grasp, even if a user is wearing gloves. This is provided through the preferred illustrated embodiments of the window latch lever that is sized, shaped, and positioned to allow greatly improved ease of use over the art. Because a single lever is employed, pinching of components is eliminated, thus reducing risk of injury to an operator. 
     The present embodiments still allow for a latching pin to be deployed into a latch pin opening along the window assembly perimeter frame. Preferred embodiments provide for multiple openings along its travel path within the perimeter frame to provide a plurality of secured positions, whether opened or closed. 
     Turning now to the Figures. Shown are the present embodiments incorporated into a large window assembly for a work vehicle. In the art, removal of large window assemblies is difficult due to their inherent size and weight. Typical configurations can include three window panes including a lower fixed pane and two upper split panes. Optionally, some panes may be slidable along a track to provide ventilation. Also, protection against stray impact to these assemblies can be included through fixed caging. 
     Generally, one embodiment of the present design is provided for a three glass panel window unit assembly with a center bar separating two upper panels from a fixed lower panel and is generally indicated at  20  in the Figures. The window unit can be attached to any number of wall openings in a variety of applications. Preferably, the wall is upright. As shown in  FIG. 1 , window unit  20  is preferably formed by a perimeter frame  24  that is fused at all joints. Perimeter frame  24  can be formed from extruded aluminum, composites, plastics, other metals, and combinations thereof. In the illustrated embodiment of  FIG. 1 , two break points  60  and  62  are shown in perimeter frame  24 . Break points  60  and  62  can be sealed by any means to provide a weatherproof seal, and can include welding (such as arc welding or spot welding), gluing, or use of fastening means, such as screws, rivets, and the like. Where fastening means are used, a powder coating over fastened break points  60  and  62  can provide additional weatherproof sealing. Perimeter frame  24  can have an interior channel  66  configured to receive a perimeter channel seal  58 . Perimeter channel seal  58  (and all seals to the window panes) can be made of an elastomeric substance suited to provide a friction fit and weather tight seal for window unit  20  window panes. The friction fit is also configured to allow a user to be able to remove the glass pane without use of additional tools and in some instances allow a window pane to slide to create an opening. 
     For illustrative purposes, the embodiments of the present window unit provide two upper panes  22   a  and  22   b , and a lower pane  22   c . Panes  22  can be held stationary in the assembled position by perimeter seal  58  and a center bar  26 . Pane  22   a  can be held on its lower edge within center bar  26  channel having seal  41 . Pane  22   a  can also be held in place along its upper edge by a perimeter seal. Pane  22   b  can be held stationary on its lower edge within center bar  26  channel having seal  43  and along its top edge by a second perimeter seal. Pane  22   c  can be held in place on its upper edge by seal  42  disposed within a lower center bar channel. Again, seals  40 ,  41  and  42  provide a friction fit to hold the pane in place and provide a weather tight seal. 
     Also, as shown, pane  22   a  is slideable from a closed position to an open position  68  (See  FIGS. 3 and 5 ). Therefore seal  42  friction fit should allow a user to slide pane  22   a  from an open and closed position while maintaining a seal against weather. Stop  124  (See  FIG. 6 ) prevents opening pane  22   a  past a predetermined point. In this case, stop  124  is configured to be ahead of the radius  126  in the upper corner of perimeter frame  24 . 
     As shown in the Figures, the latching mechanism of the present embodiments can be positioned on a housing bar  82  that can be permanently affixed to pane  22   a  on its reward vertical edge and can have weather tight seal edge  84  to seal the area between panes  22   a  and  22   b . As shown in  FIGS. 7 and 8 , pane  22   a  can be attached to housing bar  82  by an adhesive within a channel  120 . 
     As illustrated, pane  22   a  can be held secured in place along its travel path by use of a latching mechanism actuated by window latch handle  34 . Latch handle  34  can be closed ( FIG. 1 ) in an operational mode to engage a latch pin  78  in a latch pin recess/opening  114  within perimeter frame  24  to restrict pane  22   a  from sliding, or to an open position  34   a  ( FIG. 1 ) to retract latch pin  78  from opening  114 . Thus, pane  22   a  can be held in place by a window latch pin  78 , which can be actuated to be inserted into a plurality of perimeter frame  24  latch holes  114 . It is noted that the present window configuration is for illustration purposes only and other possible configurations are possible as to the number of window panes and openability of those panes. 
     The latching mechanisms of the present embodiments are thus a housing bar  82  attached to pane  22   a  as shown generally in  FIG. 1  with a seal  84  to provide a weather seal between panes  22   a  and  22   b . A latch handle  34  actuates the release of a latch pin  78  within a latch pin hole  114  in perimeter seal  24 . Latch handle  34  is sized, shaped, and positioned to allow greatly improved ease of use. As shown, latch handle  34  is a single lever that in its operational position extends beyond housing bar  82  at an angle (approximately 20 to 160 degrees from the axis of housing bar  82 , and preferably about 30 to 45 degrees) to allow easy grasping by a user, even if gloves are worn. Latch handle  34  is also preferably positioned to have a straight line pull to slide pane  22   a . Thus, latch handle  34  is preferably placed along a window pane edge that is generally perpendicular to its travel path, and specifically at a location on that edge that is about center to the center of mass of the window pane. Factors that can alter direct center placement of the pull and engage/disengage feature can include the geometry of the window (which alters the location of the center of mass) and the coefficient of friction of the window pane within its upper and lower seals. Thus, as illustrated, latch handle  34  provides a straight line pull to eliminate a racking condition (rotational/tilting torque) while the window pane  22   a  slides. 
     The latching mechanism (e.g., using a rack and pinion) to engage a latching pin  78  within latch pin hole  114  is disposed within a channel  116  of housing bar  82 . As shown in  FIG. 2 , latch handle  34  connects to a drive gear  110  disposed within channel  116 , which are both pivotable/rotatable around an axis of pivot point  112 . Adjacent and engaged to drive locking element  110  such as a wire-wound  130  compression resistant cable  108  retained within channel  116 . 
     A first end of cable  108  can include a latch pin/tip  78  sized to be received within latch pin hole  114 . It is noted that latch pin  78  can be a separate tip, such as swedged metal or plastic, but is preferably a tip  114  formed by applying a plastic or metal material on the cable terminal end, such as dipping in a metal or plastic bath. Optionally, latch pin/tip can be a brightly visible color, such as red, which can be viewed through an optional view hole  80  to confirm that tip  78  is engaged within any of the plurality of latch pin holes  114 . Further, evidence of movement of locking element  110  can be viewable through another set of optional view holes  128  along the axis of housing bar  82 . 
     Cable  108  is biased into latch pin hole  114  by a compression spring  122  at a second cable end. Compression spring  122  provides sufficient force (e.g., about 5-20 pounds of compressive force) to drive locking element (cable  108 ) into the frame recess  114  when latch handle  34  is released and to bias cable  108  to remain in recess  114  during vehicle operation. Compressive force of the bias should also be configured to allow a user to overcome the bias with the latch handle  34  with one hand. Thus, the operational mode of the mechanism is to bias latch pin  78  into hole  114  and to hold latch handle  34  to its angled position. Drive gear  110  is positioned so that as latch handle  34  is rotated downward cable  108  withdraws/disengages from latch pin hole  114 . As shown, drive gear pivot point  112  is on the opposite side of latch handle  34 . Once disengaged, a user can maintain a grip on the latch lever to slide pane  22   a  to a desired position, where the latch handle can be released. Once released, a user can confirm that pane  22   a  is secured in place by viewing latch pin tip  78  through any of the viewing holes  80  or by the angled position of latch handle  34 . 
     The illustrated examples of the present latching mechanisms are for illustrative purposes of preferred embodiments. Many variations are possible though within the scope of these embodiments. For example, locking element  108  is shown using wire-wound cable, which is readily available as it is used for many sunroof mechanisms. Nevertheless, rods with corresponding gear teeth engaging drive gear  112  are possible. Latch handle  34  could be a twist knob with colors or indicators showing the position of the locking element  108 . Also, other means to bias cable  108  into latch pin hole  114 , such as a coil spring, rubber or elastic polymers. 
     While the embodiments and methods have been described in conjunction with specific embodiments, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description.