Abstract:
The present invention relates to a casement window locking device having improved function, including improved strength, security, and durability. The invention provides a simple, elegant casement window lock having an extended operating range, is economical to manufacture, and uses few parts.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority from provisional application Ser. No. 60/558,785, filed Apr. 1, 2004, which is hereby incorporated entirely herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to a casement window locking device having improved function, including improved strength, security, and durability. 
   BACKGROUND 
   Casement windows are hinged on one vertical edge to a window frame and swing either inward or outward. The closure and locking mechanism is typically located on the vertical edge opposite the hinged edge. 
   Casement windows have utilized various mechanisms to secure closure, primarily for safety, security, and energy efficiency. There are several problems, however, with current designs and manufacture of casement window locks. First, many casement window locks include a complex set of levers, gears, and pins. These locks are difficult and expensive to make, repair, and replace. 
   Second, many casement window locks have a restricted range of movement that does not permit the window to fully close and seal shut. This is especially so with casement window locks that are slightly out of alignment with the keeper in the adjacent window pane. This misalignment reduces the energy efficiency of the window and presents a possible security flaw. 
   Third, the complicated nature of many casement window locks and the requirement of numerous moving parts yield a bulky, unsightly device that detracts from the décor of the window. 
   Thus, there is a need for a simple, elegant casement window lock that is economical to manufacture, has an extended operating range, and uses a minimum of moving parts. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide an improved casement window lock with an extended functional operating range. 
   It is further an object of the present invention to provide an improved casement window lock that is easily assembled. 
   It is further an object of the present invention to provide an improved casement window lock that is inexpensive to manufacture. 
   It is further an object of the present invention to provide an improved casement window lock with few parts. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective drawing of the fully assembled casement window lock in the open position. 
       FIG. 2  is a perspective drawing of the fully assembled casement window lock in the closed position. 
       FIG. 3  is an exploded view of the casement window lock showing the face and back of the housing, the handle, and the striker. 
       FIG. 4  is a front plan view of the assembled casement window lock in the open position. 
       FIG. 5  is a front plan view of the assembled casement window lock in a partially closed position. 
       FIG. 6  is a front plan view of the assembled casement window lock in the closed position. 
       FIG. 7  is a front plan view of the partially assembled casement window lock with a key-actuated locking mechanism. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The invention is a locking device particularly useful for a casement window. The invention as described provides an inexpensive locking device having a superior operating range. In addition, because it includes few parts, the locking device is easily assembled. 
   Although the invention has been explained in relation to its preferred embodiments, it will be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it will be understood that the invention disclosed herein covers such modifications as adapting the invention to secure doors or gates, for example. Described hereafter is the general operation of the lock, followed by a detailed description of the internal parts and their interaction. 
   Referring to the drawings in general and  FIGS. 1 and 2  in particular, the assembled casement window lock  10  is illustrated. The lock  10  includes a housing  20  for maintaining the integrity of the assembled lock  10 . The housing  20  is further utilized to mount the assembled lock  10  on a vertical edge of a casement window frame  11 , preferably adjacent to a keeper  29  in the window sash  13 . Mounting is typically accomplished using one or more fasteners, such as one or more threaded screws, which are generally denoted herein by numeral  15 .  FIGS. 1 and 2  also illustrate other exterior parts of the lock  10  including the handle  30  and the striker  40 . 
   The raised lock handle  30  places the striker  40  in a partially lowered and retracted position. When the handle  30  is lowered, (downward arrow,  FIG. 1 ), the striker  40  extends to engage the keeper  29  (lateral arrow,  FIG. 1 ) mounted in or on the window sash  13 . As the handle  30  is further lowered (arrow,  FIG. 2 ), the striker  40  retracts into the housing  20  drawing the window sash  13  against the window frame  11 . 
   In this manner, an operator utilizes the handle  30  to execute a three-stage motion of the striker  40  to engage the keeper  29  and pull the window sash  13  to a secure closed and locked position. 
     FIG. 3  depicts an exploded view of the lock  10 . The lock  10  includes four parts. The first two parts are the face plate  21  and base plate  22  of the housing  20 . Typically, the face plate  21  and base plate  22  include at least one aperture to accommodate a fastener  15 , such as a threaded screw. The purpose of the fastener can be to hold the assembled lock  10  together or to mount the lock  10  to a surface, or both. 
     FIG. 3  depicts an opening  14  in the face plate  21  to accommodate a fastener  15 . This fastener  15  holds the assembled lock together in conjunction with the base plate  22 . Specifically, the anchor peg  24  of the base plate  22  surrounds a threaded aperture  16 . 
   In a preferred embodiment, the threaded aperture  16  of the anchor peg  24  aligns with the opening  14  in the face plate  21  such that only one fastener  15  is required to assemble the lock  10 . 
     FIG. 3  further shows a mounting opening  14 ′ in both the face plate  21  and the base plate  22 . In a preferred embodiment, a fastener  15  mounts the lock  10  via the mounting opening  14 ′ and the mounting aperture  23  (see also  FIGS. 1 and 2 ). 
   Alternatively, for aesthetic purposes, the face plate  21  may be constructed without apertures. The face plate  21  can be constructed to “snap” onto the base plate  22  using one or more tabs  31  (e.g., clips or flexible lips). For example, the tabs  31  may be positioned on either the face plate  21  or the base plate  22  and engage a corresponding recess on the other plate (not shown). The fastener is hidden underneath the face plate  21  yet accomplishes the previously discussed functions. 
   The base plate  22  further includes the previously discussed anchor peg  24 , a lower bottom striker interface  25 , an upper bottom striker interface  26 , a top striker interface  27 , and a rear interior surface  28  (see  FIG. 6 ). The anchor peg  24  provides a pivot point for the handle  30  and fixes the striker  40  in either an open (i.e., unlocked) position or a closed (i.e., locked) position. 
   The lower bottom striker interface  25 , upper bottom striker interface  26 , and top striker interface  27  guide the striker  40  through its range of motion from an unlocked position to a locked position. The rear interior surface  28  is an abutment for the back edge  45  of the striker  40  (see  FIG. 6 ). 
   The third part of the lock  10  is a handle  30  having a grip  32  for operation, a handle aperture  33  for through-mounting a fastener  15  and accommodating the anchor peg  24 , and a thumb  34 . The thumb  34  includes a rounded end  35  for interacting with the striker  40  and a flat end  36  for interacting with the anchor peg  24  (see  FIGS. 4-6 ). 
   The fourth part is the striker  40 . The striker  40  includes a hook portion  41  that engages the keeper  29 , and an aft portion  50  on the end opposite the hook portion  41 . The aft portion  50  surrounds and defines a variably contoured aperture  42 . The variably contoured aperture  42  interacts with the rounded end  35  of the thumb  34  and the anchor peg  24 . Specifically, the variably contoured aperture  42  incorporates first and second  46 , 47  recesses, which interact with the rounded end  35  of the thumb  34 , and third and fourth  48 , 49  recesses, which interact with the anchor peg  24 . The striker  40  also has a bottom edge  43 , a top edge  44 , and a back edge  45 . 
     FIGS. 4-6  illustrate the lock  10  as the handle  30  passes through its range of motion between the open ( FIG. 4 ), partially engaged ( FIG. 5 ), and closed ( FIG. 6 ) positions. 
   Shown in  FIG. 4 , the bottom edge  43  of the striker  40  rests upon the lower bottom striker interface  25  of the base plate  22 . While in the open position, the rounded end  35  of the thumb  34  engages the first recess  46  of the variably contoured aperture  42  while the flat end  36  of the thumb  34  contacts the anchor peg  24 . Likewise, the anchor peg  24  is seated within the third recess  48  of the variably contoured aperture  42 . 
   Shown in  FIG. 5 , the partially engaged lock position illustrates that as the handle  30  is lowered (downward arrow), the flat end  36  of the thumb  34  begins to pivot around the anchor peg  24  while the rounded end  35  of the thumb  34  stays within the first recess  46  of the variably contoured aperture  42 . This projects the hook portion  41  of the striker  40  outward and upward toward the keeper  29  (see lateral and upward arrows). Next, the striker  40  rises such that its bottom edge  43  rests upon the upper bottom striker interface  26 , and the hook portion  41  of the striker  40  rises (upward arrow) to engage the keeper  29 . The top edge  44  of the striker  40  contacts the top striker interface  27  of the base plate  22 . The anchor peg  24  remains seated within the third recess  48  of the variably contoured aperture  42 . 
   Shown in  FIG. 6 , the locked position depicts four actions. 
   First, as the handle  30  is fully lowered (downward arrow), the flat end  36  of the thumb  34  further pivots around the anchor peg  24 . 
   Second, the striker  40  moves in the opposite direction from the keeper  29  (lateral arrow), thereby drawing the hook portion  41  of the striker  40  against the keeper  29 . The upper bottom striker interface  26  and the top striker interface  27  of the base plate  22  guide the striker  40  via their respective contact with the bottom edge  43  and the top edge  44  of the striker  40 . 
   Third, as the striker  40  is drawn in the direction of the lateral arrow, the anchor peg  24  seats within the fourth recess  49  of the variably contoured aperture  42 , and the back edge  45  of the striker  40  contacts the rear interior surface  28  of the housing  20 . 
   Fourth, the rounded end  35  of the thumb  34  seats within the second recess  47  of the variably contoured aperture  42 . A projection  51  between the first and second recesses  46 , 47  of the striker  40  maintains the lock  10  in the closed position (see  FIG. 6 ). 
   Alternatively, the lock  10  may include a key-actuated lock mechanism as depicted in  FIG. 7 . The key-actuated lock  60  serves to secure the lock  10  (specifically the striker  40 ) in the locked position. For example, the key-actuated lock  60  may move a locking tab  61  from a first unlocked position to a second locked position. In the unlocked position, the locking tab  61  may rest within a recess (not shown) in the base plate  22 . In the locked position, the locking tab  61  will be moved to abut a portion of the striker  40  (e.g., an upper edge  52  of the striker  40 , arrow,  FIG. 7 ). In this manner, the striker  40  can not disengage the keeper  29  and the lock  10  remains in the locked position. 
   Other locking means are also suitable. For example, a similar key-actuated locking mechanism may be placed to interact with a lower edge  53  of the striker  40  in a like manner as previously described. 
   The lock  10  may be formed of a metal material, including, but not limited to, steel, titanium, brass, pewter, aluminum, or tin, or any alloys thereof. Furthermore, the metal material may be plated or coated to enhance its appearance, retard oxidation and corrosion, and to reduce the coefficient of friction between the moving parts. Substances suitable for this purpose include, but are not limited to, zinc, brass, bronze, chrome, or paint. 
   The lock  10  may also be formed from plastic. Plastic materials include, but are not limited to, fiberglass, fiberglass-reinforced nylon, glass-filled nylon, glass-filled polypropylene, polyester, and vinyl. 
   The plastic material may also be coated to enhance its appearance. In addition, the lock  10  may be constructed of a combination of metal and plastic parts, or metal parts coated with plastic. 
   It will be understood that the illustrations are for describing typical embodiments of the invention and are not be construed as limiting. Furthermore, such terms as “up,” “down,” “front,” “back,” “forward,” “rearward,” “top,” “bottom,” “outward,” and the like are used strictly for convenience. Like numbers refer to like elements throughout the drawings and specification. 
   In the specification and the drawings, typical embodiments of the invention have been disclosed. Specific terms have been used only in a generic and descriptive sense, and not for purposes of limitation. The scope of the invention is set forth in the following claims.