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FIELD OF THE INVENTION 
       [0001]    The present invention is directed to the field of window hardware, particularly window hardware for double hung windows. 
       BACKGROUND OF THE INVENTION 
       [0002]    Double hung windows are a common type of window used in many homes and remodelings. There is a frame with a pair of tracks on each side of the frame. There is a top sash and a bottom sash. The top sash typically rides in the outer tracks, i.e. the tracks in the frame closest to the outside of a building. The lower sash rides in the inner track, i.e. that track that is closest to the interior of a house. The sash has a pair of vertical stiles that are joined to upper and lower horizontal styles. One or more panes of glass are retained in the sash. There can be an inner pane and an outer pane that extends from one vertical stile to the other and from one horizontal style to the other. There can be a third pane of glass positioned similarly with a gap between the first and second panes. The gap is usually filled with an inert gas such as argon. This structure provides a window with insulating qualities. One or more muntin bars can be present to provide a look of individual lites in the window of the type that are found in older construction. 
         [0003]    In many double hung windows there is an issue of security. There is usually an outer screen that permits cooler air to ventilate into the house during the warmer months. In order to take advantage of the screen however, the bottom pane typically must be in a raised position. Double hung windows are usually provided with a sash lock that locks the lower and upper sash in position so that they cannot be opened from the outside. While this provides some security during the cooler months, the return of warm weather may make it difficult to use the sash lock in many instances. The sash lock has two positions, a locked position and an unlocked position. Thus the resident has a choice to either keep the window in a closed locked position or have the window sash unlocked and thus open to intruders. 
         [0004]    In order to provide a means of ventilating a room yet provide some security, there have been a number of night latches and vent stops that have become available in the market. One such sash stop is U.S. Pat. No. 5,248,174 owned by Ashland Products. Another type of sash stop U.S. Pat. No. 4,923,230, owned by Ro Mai. These night latches or vent stops act in a similar fashion. The night latch or vent stop is placed in the face of the upper sash. Depending on the desired amount of ventilation, the night latch can be placed at any position on the face. Once the night latch is secured in the face of the window, the tumbler can be pressed in an inward and upward fashion activating a spring mechanism that will force the tumbler to an exposed position, thus creating the impeding force required to restrict movement of the lower window sash. Other prior art vent stops are U.S. Pat. Nos. 5,553,903 and 5,806,900 both of which are owned by Ashland. 
         [0005]    As mentioned previously, the typical prior art vent stop prevented the opening of the lower sash in similar fashions. In the typical prior art the tumbler was held in a locked position via a catch portion located in the housing of the night latch. Thus, if inwardly and upwardly forces were applied perpendicularly to the face of the tumbler, these forces would release the tumbler from its locked, inactivated position, to its unlocked, activated position. 
         [0006]    While the tumblers in the prior art night latches are capable of preventing the sliding member from moving passed a certain predetermined position, these tumblers have an unfavorable characteristic. That is in the prior art vent stop, in order for the user to free the tumbler from its inactivated position to its activated position or vice versa. the user must apply a multitude of forces in a variety of different angles. 
         [0007]    Although the night latch and/or vent stops are capable of preventing the lower sash from moving passed a certain desired position, their utility is unfortunately outweighed by their inherent clumsy composition. The night latch in the present invention improves on the prior art shortcomings by implementing a unique method of activating and inactivating the tumbler from the housing, without taking away from its utility and its aesthetic quality. 
       OBJECTS OF THE INVENTION 
       [0008]    It is an object of the present invention to provide a night latch that operates more easily then the prior art night latches. 
         [0009]    It is an object of the present invention to provide an improved night latch that is more reliable in its operation then the prior night latches. 
         [0010]    It is an object of the present invention to provide a night latch that allows the user to more readily reposition the tumbler back in an inactivated position. 
         [0011]    It is still another object of the invention to allow the user the ability of activating the tumbler without the use of multiple forces to release the tumbler. 
         [0012]    It is a still further object of the present invention to provide for a more durable night latch, so as to allow for a longer period of operability. 
         [0013]    It is still a further object of the invention to provide a release mechanism for activating the tumbler from a recess position to an activated position. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention is an improved night latch or sash controlling mechanism. The improved night latch can be used with a variety of windows and doors, including but not limited to, single hung windows, double hung windows, sliding windows and doors, etc. The windows can be of the type that moves vertically or horizontally. If the windows are to move in a vertical fashion then the window will have upper and lower sashes situated in the frame of the window. If the windows are to move horizontally, then the windows will have right and left sashes situated in the window frame. A night latch for a sliding door can be installed and operated in the same manner as the sliding window, except the doors will sit in the door frame rather than a window frame. More specifically, this invention is directed to be an integral part of a sliding window or door, that is simple, inexpensive, and ergonomically superior to the prior art. 
         [0015]    In the present invention the night latch has three primary components a tumbler, button for activating the tumbler, and a housing that will accommodate the tumbler and the button. The housing is placed in a groove or recess on the face of the upper window sash. The housing is constructed so as to make for a tight, smooth, and finished appearance when inserted into the groove of the window sash. This fit will make for a aesthetically pleasing appearance. 
         [0016]    As in the prior art, a tumbler is generally used as the stopping mechanism in the night latch. In general, the tumblers are activated by applying an outside force in a multitude of ways directly to the tumbler, making for a rather difficult and sometimes impossible task. One example of this is when the spring inside the tumbler is new and rather tight. In the present invention the tumbler is activated via a separate button, located on the housing of the night latch. This allows the user to activate the tumbler with relative ease. The button in the present invention is moved laterally, not inwardly as typical in the prior art, by laterally is meant a button having a direction of motion to activate the tumbler that is generally parallel to the upper surface of the housing. The direction of the force applied depends on how the button is configured. 
         [0017]    In addition to the relative ease of operation of the improved night latch, the improved night latch has an operational cover located on the bottom of the housing, which allows for installing parts inside of the housing, by operational is meant the cover may be opened and closed. In some prior art the housing is open, thus exposing the inside parts, such as the tumbler and spring, to the outside weathering elements, such as moisture in the air, which could cause malfunction of the night latch, i.e. rusty spring. 
         [0018]    Furthermore, the night latch can be recessed with even less effort then many prior art tilt latches. If the user wished to close the night latch in the prior art, the user would have to exert an inward and downward force to deactivate the night latch. This is because the tumbler in the prior art is kept depressed via the face of the tumbler and the top plate of the housing. As mentioned previously application of these forces can prove to be rather burdensome when the night latch was fairly new. In the present improved night latch, the only force needed is a downward force, this is because of the coaction between the tensed bottom part of the button and the bottom protruding portion of the tumbler. The protruding portion of the tumbler serves a twofold function, first, it keeps the tumbler in a locked inactivated position, second, when the button is depressed it keeps the tumbler in a locked activated position. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a cross-sectional view of the night latch of the present invention in place in a portion of a sliding member frame with tumbler exposed; 
           [0020]      FIG. 2  is a side view of night latch with the tumbler exposed of the present invention; 
           [0021]      FIG. 3(   a ) is an exploded view of the tumbler and spring of the present invention; 
           [0022]      FIG. 3(   b ) is an exploded view of the tumbler and spring, with spring inside of cavity of the tumbler of the present invention; 
           [0023]      FIG. 4(   a ) is an exploded view of the tumbler, spring, and housing of the present invention; 
           [0024]      FIG. 4(   b ) is a perspective view of night latch of the present invention with tumbler exposed; 
           [0025]      FIG. 5(   a ) is an exploded view of housing, exposed tumbler, and button mechanism of the present invention; 
           [0026]      FIG. 5(   b ) is a side view of housing, exposed tumbler, and button mechanism set in housing of the present invention; 
           [0027]      FIG. 6(   a ) is an inverted view of housing, exposed tumbler, and active cover in the open position of the present invention; 
           [0028]      FIG. 6(   b ) is an inverted view of housing, exposed tumbler, and active cover in the closed position of the present invention; 
           [0029]      FIG. 7(   a ) is an exploded view of the sliding member frame, groove in sliding member frame, and night latch of the present invention; 
           [0030]      FIG. 7(   b ) is an exploded view of the sliding member frame, groove in sliding member frame, and night latch being set in groove of the present invention; 
           [0031]      FIG. 7(   c ) is a perspective view of the night latch of the present invention and sliding member frame, such as a window sash or doorframe with tumbler in the closed position; 
           [0032]      FIG. 8(   a ) is a cross-sectional view of tumbler and housing, with tumbler depressed; 
           [0033]      FIG. 8(   b ) is a cross-sectional view of tumbler and housing, with tumbler exposed; 
           [0034]      FIG. 9(   a ) is a side view of tumbler and housing, with tumbler depressed; 
           [0035]      FIG. 9(   b ) is a cross-sectional view of tumbler and housing, with tumbler depressed and cover open; 
           [0036]      FIG. 10(   a ) is a side view of protruding portion and axle of night latch; 
           [0037]      FIG. 10(   b ) are right and left side views of tumbler of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0038]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. All citied references are incorporated herein by reference in their entireties. Citation of any reference is not an admission regarding any determination as to its availability as prior art to the claimed invention. 
         [0039]    In  FIGS. 1 ,  2 , and  4 ( b ), the night latch of the present invention is shown generally at  10 . As seen in  FIG. 7(   a ), the night latch  10  is shown positioned over a slot  11  in sliding member  12 . The slot  11  is shown as having an oval shape, but any other suitable shape and size slots including but not limited to a square, rectangle, oval, etc. can be used depending on the shape of the latch. Preferably, however, the night latch  10  of the present invention will have a portion similarly shaped to the slot  11  as to present a clean appearance when placed in the stopping member  12 , as seen in  FIG. 7(   c ). In the present embodiment an oval shape for illustration purposes was used. The stopping member can be a sash, doorframe, or any other member that has another piece sliding over it, where restriction of the sliding member is desired. The tumbler  36  can be either in a raised or lowered position. When raised it prevents movement of the door or sash. 
         [0040]      FIG. 4(   a ) is a more detailed view of the contemplated night latch. A housing  13  is generally defined by a first sidewall  14 , and a second sidewall  15 , not shown, and a front wall  16 , and a rear wall  17 , and a bottom wall  18 , as shown in  FIGS. 6(   a ) and  6  ( b ). Bottom wall  18  can also serve as a cover. It is noted that the terms “front” and “rear” are used only for descriptive purposes. Sidewalls  14  and  15  are preferably the same length, as are front and rear walls  16  and  17 , respectively, providing for a preferably trapezoidal shape to housing  13 . Preferably, when in place within slot  11 , sidewalls  14  and  15  contact the edges of slot  11  to provide for a tight fit, and prevent a lateral movement of the night latch  10  within slot  11 . Front wall  16  can have a front flexible clip  19  and rear wall  17  can have a rear flexible clip In the present embodiment there is only one flexible clip, front flexible clip  19 , as seen in  FIG. 2 . Rather then use a rear clip; one can use a rear notch  20  to produce generally the same fastening effect as a rear clip, as seen in  FIGS. 2 and 6(   a ). The rear notch  20  is of a non flexible nature, it is located at the end of the housing  13 , it is created between a surface  26 , which runs parallel to lip  23 , and the bottom surface  24  of the top plate  25 . Front flexible clip  19  can extend generally in an upward fashion, originating at or near the bottom surface  21  of housing  13  and ending typically just below top plate  25 , as seen in  FIG. 4(   a ). When the night latch is  10  is depressed into slot  11  on a stopping member  12 , notch  20  and flexible clip  19  can engage a portion of the member  12 , as seen in  FIGS. 1 ,  7 ( b ), and  7  ( c ). This engagement can prevent vertical (front and back) movement of the night latch  10  within the member  12 , as well as preventing the night latch  10  from being easily dislodged from slot  11 . 
         [0041]    First sidewall  14  has an inner surface  27 , not shown, and outer surface  28  as seen in  FIG. 2 . Second sidewall  15  has inner surface  29 , not shown, and outer surface  30 , as seen in  FIG. 6(   a ). On sidewalls  14  and  15  there exists two apertures,  31  and  32  respectively, as seen in  FIGS. 5(   a ) and  6 ( a ), respectively. Preferably, apertures  31  and  32  are aligned along the same central axis and are positioned towards rear wall  17 . These apertures are designed so as to allow tumbler  36  to pivot or rotate in an outwardly fashion to an actuated position. 
         [0042]    The lip  23  attached to top plate  25  is preferably at least the same size or larger and the same general shape as slot  11 . Thus, when night latch  10  is placed into slot  11 , lip  23  will contact at least the edges of slot  11  or over spread the upper surface of the member  12 . These dimensional attributes will allow for a tight fit that will exhibit a finished smooth exterior, which can be aesthetically pleasing. Although top plate  25  is referred to as a “plate”, it is understood that housing  13 , clip  19 , lip  23  and top plate  25  can be integral pieces, without any need for adhesives or assemblage. 
         [0043]    A tumbler  36  is preferably designed to fit within cavity  35  of housing  13 , as seen in  FIG. 4(   a ). Tumbler  36  may have an upper surface  37 , which is preferably smooth and/or flat, as seen in  FIG. 10(   b ). A flat surface  37  will exhibit a more finished look for the night latch  10  when it is placed in member  12 . Tumbler  36  can have a front end  41  and a rear end  42 , along with side surfaces  39  and  40 . Tumbler  36  can have rotation members  43  and  44 , which can fit in apertures  31  and  32  respectively. The rotation members  43  and  44  can be located on side surfaces  39  and  40 , respectively, close to rear end  42 . Preferably, rotation members  43  and  44  are cylindrical pegs, which protrude from side surfaces  39  and  40  of tumbler  36 , respectively. The rotation members  43  and  44  can allow tumbler  36  to extend outwardly, thus exposing front end face  45  of tumbler  36 , which would prevent movement of sliding member. The tumbler  36  will be allowed to rotate until protruding portion  52 , as seen in  FIG. 10(   b ) and bottom surface of top plate  25  meet, as seen in  FIGS. 1 and 8(   b ). 
         [0044]    In another embodiment, rotation members  43  and  44  may be located on inside walls of  14  and  15 , respectively. In this type of embodiment tumbler  36  may have apertures or bored cavities aligned along the same central axis. The rotation members will function and operate in the same manner as mentioned in the above embodiment. 
         [0045]    Tumbler  36  has a cavity  100  that houses the plate spring  46 , as seen in  FIGS. 3(   a ) and  3 ( b ). However, this is not the only possible method of attaching a spring to tumbler  36 . For example, one could a have a peg on the bottom surface of the tumbler for receiving a spiral spring. Tumbler cavity  100  has a top and bottom surface,  47  and  48 , respectively, generally conforming to the width of plate spring  46  it houses. In the present embodiment an aperture  49  may be present on at least one side of the tumbler cavity  100 , as seen in  FIGS. 1 and 10(   b ). This acts as to further confine the plate spring  46  from coming dislodged from cavity  100 . This aperture  49  is an added movement inhibitor and is not necessary for proper operation. Because of the tight fit between tumbler  36  and housing  13  that contains it, there is usually no need for guide members on the side surfaces  39  and  40 , as in the prior art. The tumbler  36  has arcuate surface  50  on the underside thereof that interacts with a respective arcuate surface  51  of housing  13 . Arcuate surface  50  is preferably located on the rear bottom of tumbler  36 , and arcuate surface  51  is located on the inside rear end of the housing  13 , a seen in  FIG. 8(   b ). These arcuate surfaces assist in providing smooth movement of the tumbler from an activated position to a recessed position and vice versa. Tumbler  36  has a protruding portion  52  located at the bottom front end wall of tumbler  36 , as seen in  FIG. 3  ( b ). The protruding portion  52  has a top surface  57  that may extend generally perpendicularly from the front end face  41  of the tumbler  36 . The protruding portion  52  also has two sides  53 , and  54 , an inside face  56 , that extends from top surface  57  toward the bottom of tumbler  36 , notch portion  53  that extends from inside face  56  towards the front of housing  13 , and a bottom  55 . Bottom  55  of the protruding portion  52  extends outwardly in the same direction as top surface  57  so as to meet with the outside edge of  56  to form a tip  58 , as seen in  FIG. 3(   a ). The protruding portion  52  is so designed as to allow a meshing between the protruding portion  52  and the bottom groove  59  of button  60 , as seen in  FIG. 8(   a ). 
         [0046]    The release of the tumbler  36  from housing  13  can be controlled by an interaction between button  60  and protruding portion  52  of tumbler  36 . Button  60  can have a top surface  61  which is preferably in the same plane as the upper surface  37  of the tumbler  36 , as seen in  FIGS. 5(   a ) and  5 ( b ). Button  60  preferably resides in opening  62  of top plate  25 . Here, the user can access button  60  easily. Top surface  61  of button  60  can have a groove or recess  63 , where the user can engage button  60  with any suitable instrument known in the art, including but not limited to a finger, fingernail, pen, pencil etc. When the user engages groove  63 , it can move button  60  within opening  62  of housing  13 . The movement of the button moves the body of the spring clip  69  so that the protruding portion  52  is no longer blocked and the tumbler  36  may move from a recessed position to an activated position. In the present embodiment the user translates groove  63  in a motion toward the front end of the housing. Button  60  as mentioned previously has a top surface  61 , the head, and it has a bottom portion  90 , the body. The body can best be described as having two main structures, an inner structure  69  for holding tumbler  36  in housing  13  when not activated, and an outer structure  70  which keeps button  60  in its original position when no force is placed on the button. Both structures  69  and  70  join at the junction  68  of button  60 . The inner structure  69  has front and rear faces,  63  and  64 , respectively, left and right sides,  65  and  66 , respectively, and a top face  67  that sits just below the bottom of the top plate  25 . Top face  67  acts so as to keep button  60  inside of housing  13  when button  60  is translated in a downward fashion. Front and rear faces,  63  and  64 , respectively, and left and right sides,  65  and  66 , respectively, preferably taper in a downward fashion from top face  67 , a distance preferably less then that of the inside wall of housing  13 , but generally equal to that of the front face of tumbler  36 . The outer structure  70  preferably acts as a spring and has front and rear face  71  and  72 , respectively, and has left and right sides  73  and  74  respectively. The dimensions of outer structures are such dimensions so as to allow for the desired tension of button  60 . At the bottom  68  of button  60  there exists a tooth  75  formed where structures  69  and  70  join. Tooth  75  keeps protruding portion  52  in place when night latch  10  is inactive, i.e. inactive. On left and right sides,  65  and  66 , respectively, of structure  69 , there exists two pegs,  76  and  77 , as seen in  FIG. 2 . Pegs  76  and  77  could be of any suitable shape, including but not limited to a square, rectangle, cylindrical, etc. In the present embodiment cylindrical pegs were used. Pegs  76  and  77  are positioned on the upper portion of structure  69 . Both pegs,  76  and  77 , rest in apertures  78  and  79  of housing  13 , as seen in  FIG. 9(   a ) Apertures  78  and  79  are aligned along the same central axis and are of the shape as to allow for unimpeded translation of pegs  76  and  77 . In the present embodiment oblong apertures were used. 
         [0047]    In another embodiment pegs  76  and  77  may be located on housing  13 , and structure  69  may have apertures or bored cavities to receive corresponding pegs. The functionality of the pegs and apertures may serve the same function as mentioned above. 
         [0048]    On housing  13 , the bottom plate  18  may have an operable cover  82  for installing one or more parts into housing  13 , as seen in  FIGS. 6  ( a ) and ( b ). Any suitable shape cover can be implemented, including but not limited to a square, rectangle, circle, etc. In the present embodiment a rectangular cover and opening were used. 
         [0049]    When the user wishes to activate tumbler  36  so as to cease movement of sliding member, the user will exert a force, greater then that of button portion  70 , on groove  63 , of button  60 . This force will cause button  60  to move in a direction opposite that of the stored potential energy of button portion  70 , thus causing release portion  75  of button  60  to disengage tumbler  36 . When tumbler  36  is free to pivot on rotation members  43  and  44 , the upward force of spring  46  will cause tumbler  36  to rotate in an outwardly direction until protruding portion  52  and bottom surface of top plate  25  meet, at which time stopping surface  45  of tumbler  36  will be exposed, thus preventing sliding window member from opening any further. When tumbler  36  is exposed, i.e. activated, and the user releases groove  63 , button portion  70  will return to its original position. When the user wishes to deactivate the tumbler, the user may apply a force, in a generally perpendicular direction, to a portion of top surface  37  of tumbler  36 . At this time release portion  75  of button  60  will engage tumbler  36 . 
         [0050]    As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense. In the view above it will be seen that several objects of the invention are achieved and other advantageous results attained, as defined by the scope of the following claims.

Summary:
The present invention relates to a night latch, in particular a night latch that includes a housing, tumbler, button, and a resilient members. The housing of the present invention maintains the tumbler, button, and resilient members. The housing also may have at least one protrusion located on its sidewall. The tumbler of the present invention has a pivoting member along with a means for housing a resilient member. In addition, the tumbler of the present invention may have a tooth-like member located on its front face, which interacts with a protrusion located on the rear end of lower portion of the button. The lower portion of the button also has a resilient member located on the front end. This resilient member exerts a force that maintains the tumbler in a retracted position.