Patent Publication Number: US-6698970-B2

Title: Multipoint locking mechanism for window sash

Description:
TECHNICAL FIELD 
     The present invention generally relates to window assemblies and, more particularly, to mechanisms for multipoint locking of a window sash to a window frame. 
     BACKGROUND ART 
     Window sashes are mounted in window frames and the window sashes either slide, rotate or pivot in the window frame between fully open and closed positions, or any position therebetween. Various locking devices have been provided in order to lock window sashes to their respective window frames when the window sashes are in the closed position. Namely, U.S. Pat. No. 5,118,145, issued to Tucker on Jun. 2, 1992, U.S. Pat. No. 5,791,700, issued on Aug. 11, 1998 to Biro, U.S. Pat. No. 5,829,802, issued on Nov. 3, 1998 to Anderson et al., and No. 5,927,768, issued on Jul. 27, 1999 to Dallmann et al., each describe locking systems for window sash/window frame assemblies that qualify as being multipoint. Multipoint locking mechanisms for window sash comprise at least two pairs of interacting members that interact to lock the window sash to the window frame in at least two different points. Having multiple points of locking between a window sash and a window frame ensures a secure locking therebetween. A multipoint lock is also desirable as it prevents warping of the window sash and maintains it flush with the window frame and the weather stripping thereof to assure a good seal. If the sash is warped, the multipoint lock will exert a force on the sash to straighten it in the window frame. The points of lock allow the window sash to exert a uniform pressure on the window frame, and therefore a tight seal between the window frame and the window sash is maintained. 
     It is known to provide multipoint locking wherein the window lock has ramped keepers secured to the window sash and cam rollers on a slider bar which is mounted to the window frame. The slider bar translates up and down on a side wall of the window frame in response to manual or motorized actuation of a handle. By displacing the slider bar upward, the cam rollers on the slider bar, which may also be cams or mushroom cams, each engage a ramped portion of a respective ramped keeper so as to lock the window sash to the window frame. It is pointed out that the window sash must be generally closed for the rollers to engage the ramped keepers, yet the ramped portions of the ramped keepers ensure that the window sash will lock even when the window sash is not completely closed. When the window sash is locked, the rollers of the slider bar rest against a flat surface of the ramped keepers and prevent the opening of the window sash. 
     SUMMARY OF INVENTION 
     It is a feature of the present invention to provide an improved multipoint locking mechanism for window sashes and wherein the keeper and cam are both wedges that provide increased surface engagement and a greater displacement span. 
     According to the above feature of the present invention, and from a broad aspect thereof, the present invention provides a cam wedge for a locking mechanism for locking a window sash in a closed position in a window frame. The locking mechanism is of the type having a slider portion translating longitudinally on a window frame in response to an actuation of a handle to engage at least two engagement members of the slider portion with corresponding keeper portions secured on the window sash for locking the window sash to the window frame. The cam wedge comprises a body having at least one ramped portion and a rest portion. The cam wedge is secured to the slider portion to be one of the at least two engagement members such that the at least one ramped portion abuts a corresponding keeper portion during a translation of the slider portion, and is guided by the corresponding keeper portion to abut the rest portion thereagainst to prevent a displacement of the window sash toward an open position thereof. 
     In accordance with a further broad aspect of the present invention, there is provided a multipoint locking mechanism for locking a window sash in a closed position in a window frame. The locking mechanism is of the type having a slider portion translating longitudinally in a window frame in response to an actuation of a handle to engage at least two engagement members of the slider portion with corresponding keeper portions in the window sash for locking the window sash to the window frame. At least one of the at least two engagement members is a cam wedge having at least one ramped portion and a rest portion. The cam wedge is positioned on the slider portion such that the at least one ramped portion abuts the corresponding keeper portion during a translation of the slider portion, and is guided by the corresponding keeper portion to abut the rest portion thereagainst to prevent a displacement of the window sash toward an open position thereof. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
     FIG. 1 is a perspective view of a window having a multipoint locking mechanism in accordance with the present invention; 
     FIG. 2 is a front elevational view, partly fragmented, showing the multipoint locking mechanism secured between a window frame and sash and disposed at an unlocked position; 
     FIG. 3 is a cross-sectional view showing the multipoint locking mechanism and taken along cross-sectional lines III—III of FIG. 2; 
     FIG. 4 is a front elevational view, partly fragmented, showing the multipoint locking mechanism in a locked position; 
     FIG. 5 is a cross-sectional view of the multipoint locking mechanism taken along cross-sectional line V—V of FIG. 4; 
     FIG. 6A is an enlarged front elevational view of a cam wedge and keeper wedge pair of the multipoint locking mechanism in the unlocked position; 
     FIG. 6B is an enlarged perspective view of the cam wedge and keeper wedge pair of the multipoint locking mechanism in the unlocked position; 
     FIG. 7A is an enlarged front elevational view of the cam wedge and keeper wedge pair of the multipoint locking mechanism in the locked position; 
     FIG. 7B is an enlarged perspective view of the cam wedge and keeper wedge pair of the multipoint locking mechanism in the locked position; 
     FIG. 8 is a cross-sectional view of the multipoint locking mechanism taken along cross-sectional line VIII—VIII of FIG. 4; 
     FIG. 9 is a perspective view of the cam wedge of the locking mechanism; 
     FIG. 10 is a perspective view of a keeper wedge of the locking mechanism; 
     FIG. 11 is a perspective view of a cam wedge of the locking mechanism in accordance with another embodiment of the present invention; and 
     FIG. 12 is a perspective view of the cam wedge in accordance with another embodiment of the present invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to the drawings and, more particularly, to FIG. 1, a window sash  10  is shown pivotally mounted to a window frame  12 , with a handle  14  at a base of the window frame  12  rotatable for opening and closing the window sash  10 . For simplicity purposes, the multipoint locking mechanism of the present invention will be referred to hereinafter as “the locking mechanism  20 .” The locking mechanism  20 , not shown in FIG. 1, has a handle  22 , pivotable between a locking position A and an unlocked position B, to lock/unlock the window sash  10  in the frame  12 . 
     Referring now to FIGS. 2 and 3, the locking mechanism  20  is shown, and it has a slider bar  24  extending generally a predetermined length between a bottom and a top of the window frame  12 . The slider bar  24  is a steel bar slidingly mounted to the window frame  12  so as to slide between an unlocked position, as illustrated in FIGS. 2 and 3, and a locking position, which will be described hereinafter and is illustrated in FIGS. 4 and 5. The slider bar  24  is displaceable between its unlocked position and its locking position by the actuation of the handle  22 . Accordingly, the locking and unlocking positions of the slider bar  24  correspond to the locking and unlocking positions of the handle  22 . The handle  22  has a fork  26  which is displaced by an actuating linkage  23 . The fork  26  is coupled to a pin  28  secured to the slider bar  24  and actuates the displacement of the slider bar  24  between the unlocked position and the locking position. 
     As shown in FIG. 3, the slider bar  24  has a cam wedge  30  in a middle portion thereof. Although the cam wedge  30  is illustrated in the middle portion of the slider bar  24 , it may be at any position thereon, such as ¼, ⅓, ½ of the height, or any other specified position. As shown in FIG. 9, the cam wedge  30  has a trapezoid-shaped body  31  with ramped portions  32  and  34  and a flat rest portion  36 . A slider bar contact surface  38  of the body  31  has a pair of protrusions  40  projecting outwardly therefrom. A through bore  42  is provided in the body  31  and extends therethrough from the slider bar contact surface  38  to an outer surface  44 , with the portion of the through bore  42  emerging out of the outer surface  44  being countersunk. When the cam wedge  30  is secured to the slider bar  24 , the protrusions  40  are received in corresponding holes in the slider bar  24  to arrest the cam wedge  30 , and a fastener, such as a screw, a bolt, or a rivet, fastens the cam wedge  30  to the slider bar  24 . As shown in FIG. 3, when the cam wedge  30  is secured to the slider bar  24 , the ramped portions  32  and  34  and the flat rest portion  36  face toward the interior side of the window frame, i.e., the side of handle  22 . A first lip  46  projects outwardly from the slider contact surface  38  and abuts a side edge surface of the slider bar  24  to ensure the stability of the connection between the cam wedge  30  and the slider bar  24 . A second lip  48  extends outwardly from the ramped portions  32  and  34  and the flat rest portion  36 . The use of the second lip  48  will be described hereinafter. 
     Returning to FIGS. 2 and 3, the three keeper wedges  50  are shown secured to the window sash  10 . Referring to FIG. 10, one of the keeper wedges  50  is shown in greater detail. The keeper wedge  50  has a trapezoid-shaped body  51 . The body  51  has ramped portions  52  and  54  and a flat rest portion  56 . A flange  58  extends outwardly from the ramped portions  52  and  54  and the flat rest portion  56 , and has a pair of beveled through bores  60 , so as to be secured by fasteners such as screws or bolts to the window sash  10 . A lip  61  projects upwardly from the ramped portions  52  and  54  and the flat rest portion  56 , and its use will be described hereinafter. 
     Referring to FIGS. 2 and 3, the slider bar  24  is shown in its unlocked position, with the window sash  10  in a generally closed position with respect to the window frame  12 . The locking mechanism  20  illustrated in FIGS. 2 to  5  has one cam wedge  30  in a middle of the slider bar  24 , and rollers  62 , which may be mushroom cams, at top and bottom ends of the slider bar  24 . When the slider bar  24  is in its unlocked position, the cam wedge  30  thereon is slightly below the middle keeper wedge  50 . This is best seen in FIG.  7 B. Similarly, the rollers  62  are also slightly below corresponding ones of the keeper wedges  50 . 
     To lock the window sash  10  to the window frame  12 , the handle  22  is gradually displaced from its unlocked position to its locked position. This will result in a gradual upward motion of the slider bar  24 , such that the rollers  62  and the cam wedge  30  thereon will come into contact with the keeper wedges  50 . More precisely, as shown in FIG. 7B, the ramped portion  32  of the cam wedge  30  will meet the ramped portion  52  of the middle keeper wedge  50 , and one will slide on the other, thereby pulling the window sash  10  toward the window frame  12 . Once the ramped portions  32  and  52  are past one another, the flat rest portions  36  and  56  will slide on one another until the slider bar  24  reaches its locking position, at which point the flat rest portions  36  and  56  will rest in abutment one against the other. 
     Similarly, the rollers  62  will end up resting against the flat rest portion  56  of the uppermost and lowermost keeper wedges  50 . However, instead of having a ramped portion  32  sliding against a ramped portion  52  of the keeper wedge  50 , the rollers  62  will roll or slide on the ramped portions  52  of the keeper wedges  50  until the rollers  62  are past the ramped portions  52 , at which point they will roll on the flat rest portions  56  of the keeper wedges  50 . When the slider bar  24  reaches its locking position, the rollers  62  will rest in abutment against the flat rest portions  56  of the keeper wedges  50 . 
     Accordingly, the abutment between the keeper wedges  50  and the rollers  62  and the cam wedge  30  prevents the opening of the window sash  10 , whereby the window sash  10  is said to be locked to the window frame  12 . As best seen in FIG. 7B, the cam wedge  30  will be an obstacle that will prevent the keeper wedge  50  from moving in the direction of arrow A, i.e., from moving in an opening direction of the window sash  10 . Although not illustrated, the rollers  62  also act as an obstacle to the opening of the window sash  10  by resting in abutment against the flat rest portions  56  of the keeper wedges  50 . 
     Furthermore, as best seen in FIG. 7A, the second lip  48  of the cam wedge  30  abuts against the lip  61  of the keeper wedge  50 , such that the window sash  10  cannot be tampered with laterally, i.e., in the direction of arrow B, so as to surround the cam wedge  30  to open the window sash  10 . Similarly, the rollers have mushroom heads that abut against the lips  61  of the keeper wedges  50 . 
     It has been thought to position the cam wedge  30  and the rollers  62  on the slider bar  24  such that the cam wedge  30  initiates the locking of the window sash  10  to the window frame  12  as explained above, while the rollers  62  have yet to come in contact with their respective keeper wedges  50 . More specifically, once the ramped portion  32  of the cam wedge  30  has met the ramped portion  52  of the middle keeper wedge  50  and has started sliding thereon, one of the rollers  62 , such as the lower one, engages its corresponding keeper wedge  50 , to finally be followed by the upper roller  62 . Thus, this position of the cam wedge  30  and the rollers  62  creates a gradual step locking action of the window sash  10  to the window frame  12 . 
     To unlock the window sash  10  from the window frame  12 , the handle  22  is displaced from its locking position to its unlocked position. By doing so, the slider bar  24  is gradually displaced from its locking position (as shown in FIGS. 4 and 5) to its unlocked position (as shown in FIGS.  4  and  5 ), thereby moving the cam wedge  30  and the rollers  62  away from the keeper wedges  50 . Accordingly, the cam wedge  30  and the rollers  62  are no longer obstacles that prevent the window sash  10  from being opened. 
     Although the locking mechanism  20  illustrated in FIGS. 2 to  5  has one cam wedge  30  for two rollers  62 , it is obvious that the locking mechanism  20  may be provided with three cam wedges  30 . The locking mechanism  20  is said to be “multipoint,” as it has at least two points of contact between the window sash  10  and the window frame  12 , namely the cam wedge  30  and the middle keeper wedge  50 , and the rollers  62  and the end keeper wedges  50 . Although the locking mechanism  20  illustrated in FIGS. 2 to  5  has three points of contact, two points of contact could also have been sufficient, and four or more points of contact could be used for higher windows. Also, the above described offsetting of the cam wedge  30  and the rollers  62  may also be performed on a locking mechanism  20  having only cam wedges  30 . It is obvious that one can position the keeper wedges  50  on the window sash  10  to create the gradual step locking action. 
     The use of a cam wedge  30  interacting with a keeper wedge  50  provides a few advantages. Namely, the closing action created by the locking of the window sash  10  to the window frame  12  involves a greater displacement of the window sash  10  with respect to the window frame  12  when compared to a roller performing the locking, in the event where the roller has a diameter similar to the width of the cam wedge  30 . In order for a roller to engage the ramped portion  52  of the keeper wedge  50 , the ramped portion  52  of the keeper wedge  50  must come into contact with the roller at least in alignment with the center of the roller, otherwise there is no engagement between the roller and the keeper wedge  50 . On the other hand, the ramped portion  32  of the cam wedge  30  needs only to have its tip come into contact with the tip of the ramped portion  52  of the keeper wedge  50  in order to engage therewith. 
     Referring to FIG. 8, the increased displacement in the closing action resulting from the locking of the window sash  10  to the window frame  12  enables a greater compression of resilient sealing means  64  located on the periphery of the window sash  10  and coming into contact with various portions of the window frame  12  to assure the sealing therebetween. 
     The cam wedge  30  is solidly secured to the slider bar  24  by its protrusions  40 , its lip  46  and the fastener received in the through bore  42 . In comparison, a roller has one connection point with the slider bar  24 , i.e., its pivot. Therefore, pivots are more prone to break as a result of a force applied to the window sash than an engagement member, such as the cam wedge  30 , that is secured to the slider bar  24  in at least two points. 
     The cam wedge  30  and the keeper wedges  50  are each shown having two ramped portions. Although only one ramped portion is used, the cam wedge  30  and the keeper wedges  50  may be used with window sashes closing from either side. The cam wedge  30  of FIG. 9 must however be turned according to the side the window will be opening, and the fasteners used therewith must allow the cam wedge  30  to be detached from the slider bar  24 . Therefore, savings are involved in the manufacturing of only one type of cam wedge and one type of window that will serve on left or right sides of windows. However, the cam wedges  30  illustrated in FIGS. 11 and 12 may also be used in accordance with the present invention. The cam wedge  30  illustrated in FIG. 12 is universal as it positioned in the same manner whether it is on a right-side or left-side closing window and does not need to be turned during installation according to the side the window will be opening. However, it only provides half the travel or displacement the cam wedges  30  illustrated in FIGS. 9 and 11 provide. The cam wedge  30  of FIG. 11, on the other hand, may only be used on one side. Finally, although the slider bar  24  is shown translating up and down, it is obvious that the locking mechanism  20  may be set in the window frame  12  horizontally. 
     It is within the ambit of the present invention to cover any obvious modifications of the embodiments described herein, provided such modifications fall within the scope of the appended claims.