Abstract:
A power-operated latch is integrated to a casement window for selectively locking and unlocking a vertically hinged window sash. The power-operated latch is adapted to be concealed in the window frame and is directly connectable to the existing window latch hardware. A reversible rotary motor drives a lead screw on which a slider is threadably engaged for pivoting a lever connected to a longitudinally movable latch bar.

Description:
RELATED APPLICATION 
       [0001]    The present application is a continuation-in-part of U.S. patent application Ser. No. 12/428,498 filed on Apr. 23, 2009 the content of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The application relates generally to casement windows and, more particularly, to a motorized window latching system. 
       BACKGROUND OF THE ART 
       [0003]    Casement windows are well known. Such windows typically have one or more window sash pivotable about a vertical axis between an open and a closed position. A latch bar is commonly employed to lock the window sash in its closed position in tight sealing engagement against the window frame. Such latch bars generally include a flat steel strip having various latch points therealong for engagement with corresponding keepers provided along an edge of the associated window sash. The latch bar is typically manually actuated by a pivotable lever or lock handle. 
         [0004]    Heretofore, the motorisation of casement window latch mechanisms has been challenging. In most instances, access to the window latch bar is difficult and there is very little room to position the motorized operator. Also the motorized latch operator must not adversely affect the aesthetic of the window in order for the product to gain commercial acceptance. 
         [0005]    There is thus a need for a compact motorized latch operator that can be integrated into a casement window without adversely affecting the appearance thereof. 
       SUMMARY 
       [0006]    It is therefore an object to provide a compact motorized latch operator that can be integrated to a casement window. 
         [0007]    In one aspect, there is provided a motorized latch operator adapted to be retrofitted to a normally manually operated latching assembly of a casement window mounted in a building wall, the casement window having at least one window sash hingedly mounted in a casement for pivotal movement about a vertical axis between open and closed positions, keepers being provided along one side of the window sash for engagement with corresponding latches mounted on a vertical side frame member of the casement, the latches being operatively interconnected by a vertical latch bar mounted for longitudinal movement in a gap defined between the side frame member and a moulding member; the motorized operator comprising a support frame mounted in a casing integrated to a building wall next to the casement, a reversible rotary motor hingedly mounted to the support frame, a lead screw drivingly connected to the reversible rotary motor, a slider threadably engaged on the lead screw for movement therealong, a lever pivotally mounted at a first end portion thereof to the support frame, the slider being engaged with the lever to pivot the same in response to a movement of the slider along the lead screw, the lever being pivotally connectable at a second end portion thereof to the vertical latch bar to linearly displace the same when pivoted as a result of the movement of the slider on the lead screw. 
         [0008]    In a second aspect, there is provided a power-operated latch assembly for a casement window mounted in a building wall, the casement window having at least one window sash hingedly mounted in a window frame for pivotal movement about a vertical axis between open and closed positions; the power-operated latch assembly comprising at least two keepers mounted to the window sash for locking engagement with corresponding latches operated by a latch bar mounted for vertical movement along one vertical member of the window frame, a reversible operator mounted to a support frame disposed in the building wall adjacent to the casement window, a lever pivotally mounted to the support frame and having a first end drivingly connected to said reversible operator and a second end pivotally connected to the latch bar, the pivotal movement of the lever by the reversible operator causing the linear movement of the latch bar. 
         [0009]    In a third aspect, there is provided a casement window comprising at least one window sash hingedly mounted in a window frame for pivotal movement about a vertical axis between open and closed positions, a power-operated latch mechanism for releasably locking the at least one window sash in the closed position, the power-operated latch mechanism comprising at least two keepers mounted to the window sash for locking engagement with corresponding latches operated by a latch bar mounted for vertical movement along one vertical member of the window frame, a reversible rotary motor mounted in one of a cavity defined in the building wall and an internal cavity defined in the window frame, a vertically supported lead screw drivingly connected to the reversible rotary motor, a vertically displaceable slider threadably engaged on the lead screw for linear movement therealong, and a link between the slider and the latch bar, the link transferring the movement communicated to the slider to the latch bar. 
         [0010]    Further details of these and other aspects of the present invention will be apparent from the detailed description and figures included below. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0011]    Reference is now made to the accompanying figures, in which: 
           [0012]      FIG. 1  is a perspective view of a double hung casement type window as seen from inside a room and having a motorized unlatching system mounted inside the central profiled post of the window casement, the front vertical moulding normally covering the central profiled post being omitted to reveal the normally hidden motorized unlatching system; 
           [0013]      FIG. 2  is a perspective view of the motorized unlatching system together with the window original latching hardware shown in isolation; 
           [0014]      FIG. 3  is a cross-sectional view taken along line  3 - 3  in  FIG. 1 ; 
           [0015]      FIG. 4  is a longitudinal cross-sectional view illustrating the motorized unlatching system in position in the central profiled post of the window casement; 
           [0016]      FIG. 5  is a perspective view of another model of double hung casement type window, the vertical moulding along one side of the central post of the window being broken away to show part of a motorized latching system; 
           [0017]      FIG. 6  is a vertical cross-sectional view illustrating the details of the motorized latching system of  FIG. 5 ; 
           [0018]      FIG. 7  is a perspective view of a single hung casement window, the vertical moulding along one side of the window frame being omitted to reveal details of a motorized latching system connected to the original manual latching system of the window; 
           [0019]      FIG. 8  is vertical cross-sectional view illustrating the details of the motorized latching system shown in  FIG. 7 ; 
           [0020]      FIG. 9  is a top plan view of a motorized unlatching system in accordance with a further embodiment of the present invention; 
           [0021]      FIG. 10  is a cross-sectional view taken along line  10 - 10  in  FIG. 9 ; 
           [0022]      FIG. 11  is a side view of the system shown in  FIG. 9 , and 
           [0023]      FIG. 12  is a cross-sectional view taken along line  12 - 12  in  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]      FIG. 1  illustrates a first example of a conventional casement window  10  to which a motorized latching system or operator  12  can be integrated or retrofitted to provide for motorized latching and unlatching of the window. The illustrated exemplary casement window  10  is of conventional double hung casement type comprising a pair of window sashes  14  hingedly mounted in a casement  16  for pivotal movement between open and closed positions about mobile vertical axes at opposite sides of the casement  16 . 
         [0025]    The casement window  10  is provided with latching hardware to releasably secure the window sashes  14  in their closed position. The latching hardware can comprise a plurality of keepers  18  (two in the illustrated example) on each window sash  14  for engagement with corresponding attachment points or latches  20  mounted on opposed longitudinal exterior sides of the central profiled post  22  of the casement  16 . The latches  20  capture the keepers  18  and operation of the latches  20  draw the corresponding window sash  14  into its closed position where it is locked. In the closed position, the window sash  14  is seated in the frame and compresses weather stripping (not shown) to seal the window assembly. In the illustrated example, the latches of each set of latches  20  are interconnected by a latch bar  24  adapted to transmit the movement from one latch to another, thereby allowing for joint operation of the latches  20  of a same set. The latch bars  24  are typically made from flat steel strips mounted for linear sliding movement against the exterior longitudinal sides of the central profiled post  22  of the casement  16 . 
         [0026]    Instead of manually actuating the interconnected latches  20  via a conventional lever or handle provided at one of the latching points on each side of the central profiled post  22 , it is herein proposed to nest a power-operated or motorized latch actuator system  12  in an existing frontal opening defined in the central profiled post  22  and to connect the system  12  directly to the existing latch bars  24  on each side of the central profiled post  22 . Once installed, the motorized system  12  is hidden behind the front moulding (not shown) normally covering the post  22  when viewed from inside the room in which the window is mounted. By taking advantage of the existing free internal space offered by the central profiled post  22 , it is possible to completely conceal the system  12  within the window casement  16 , thereby preserving the overall appearance of the window. 
         [0027]    As best shown in  FIG. 2 , the system  12  generally comprises at least one reversible actuator, such as electrical reversible rotary motor  26 , a push and pull rod which can take the form of a lead screw  28  drivingly connected to the motor  26 , a slider  30  threadably engaged on the lead screw  28  for linear movement within the profiled post  22  ( FIG. 1 ) in the upward and the downward directions, and a pair of link plates  32  mounted to opposed sides of the slider  30  in order to rigidly connect the slider  30  to the lock bars  24  of the window  10 . An example of a suitable actuator is the 12 DVC E Type Inline DC Gearmotor Model No. 8501 manufactured by Merkle-Korff Industries. The dimensions of the selected actuator must allow the same to be fully contained within the central profiled post  22 . The motor  26  is connected to a source of power (not shown), such as a battery. The lead screw  28  can consist of a stainless steel screw with ACME threads. The slider  30  can be manufactured in a block of polytetrafluoroethylene or from another solid block of low friction material in order to minimize the friction between the lead screw  28  and the slider  30 . 
         [0028]    The system  12  further comprises a support  36  for supporting the motor  26  and the lead screw  28  and facilitating mounting of the system  12  within the central profiled post  22  of the casement window. The support  36  comprises an elongated back  38  and top and bottom L-shaped plates  40  and  42  mounted at opposed ends of the elongated back  38 . The elongated back  38  provides a mounting surface for fixedly mounting the system  12  into central profiled post  22  of the casement  16 . 
         [0029]    Holes can be defined through the back of the support  36  for receiving mounting screws or the like. The motor  26  is mounted to the undersurface of the bottom L-shaped plate  42 . A support block  41  having a screw receiving hole depends from the top L-shaped plate  40  for receiving a tip end portion of the lead screw  28 . Limit switches  46   a,    46   b  and  46   c  are mounted to the front face of the support back  38  above and below the slider  30 . Projections  48   a,    48   b,    48   c,  such as screws, are provided on the top and bottom surfaces of the slider  30  to trigger the limit switches  46   a,    46   b  and  46   c  when the slider  30  reaches its top and bottom travel limits. The limit switches  46   a,    46   c  are operatively connected to the motor  26  to shut down the same and reverse the direction of movement once triggered by a corresponding one of the triggering projections  48   a,    48   c,  thereby defining the range of motion or stroke of the slider  30  on the lead screw  28 . The third limit switch  46   b  is used as an interlock. The limit switch  46   b  is provided to prevent the motor (not shown) used to displace the window sashes  14  between their open and closed positions from being operated when the latches  20  are engaged with the keepers  18 . It is provided to “sense” the lock state of the window sashes. It can also be used to prevent the motor  26  of the power operated latching system from being operated when the window sashes are opened. 
         [0030]    The motor  26 , the lead screw  28 , the slider  30 , the support block  44  and the limit switches  46   a,    46   b,    46   c  are pre-assembled on the support  36  and this sub-assembly is mounted within the central profiled post  22 , such as by screwing the support back  38  to a corresponding back surface of the casement window central profiled post  22  . As shown in  FIG. 4 , the central post  22  is provided in the form of an extrusion having a generally C-shaped profile with a front open face. The central post  22  has a frontal recess defined by sidewall surfaces  50  and inwardly projecting frontal wall surfaces  52 . The slider  30  has a generally T-shaped body including a rearwardly projecting shank portion  54  and lateral shoulders  56 . The shank portion  54  is received between the frontal wall surfaces  52  of the profiled post  22  with the lateral shoulders  56  resting against a front side of the frontal wall surfaces  52  between said sidewall surfaces  50 . This arrangement prevents the slider  30  from rotating together with the lead screw  28 . The slider  30  is thus constrained to move linearly in the upward or the downward direction depending whether the motor  26  is rotatably driving the lead screw  28  in the clockwise or the counter-clockwise direction. 
         [0031]    Still referring to  FIG. 4 , it can be appreciated that the lock bars  24  interconnecting the latches  20  ( FIG. 1 ) are guided in vertical tracks defined at the outer sides of the central profiled post  22 . The link plates  32  are positioned laterally outwardly from the sidewall surfaces  50  of the post  22  and are fixedly attached to the lock bars  24  by fasteners such as screws or the like. Vertically elongated slots  58  had to be machined (also see  FIG. 3 ) in the post sidewall surfaces  50  for allowing the link plates  32  to be rigidly connected to the slider  30  by means of shoulder screws  57 . In this way, the linear movement of the slider  30  inside the post  22  can be simultaneously transmitted to both latch bars  24  on the opposed sides of the central profiled post  22 . The length of the elongated slots  58  is selected to accept the full stroke of the slider  30  as set by the position of the limit switches  46 . 
         [0032]    In use, a remote control can be used to operate the system  12 . A wireless control receiver (not shown) can be mounted in the building wall underneath the window frame for receiving control commands and transmitting same to the electric motor  26 . The rotational movement of the lead screw  28  causes the linear displacement of the slider  30  which in turn push or pull on the lock bars  24  (depending in which direction the screw is rotated) to actuate the latches  20  in order to lock or unlock the window. 
         [0033]    If more torque is required to operate the latches, a second motor and a second lead screw could be added to the above described latch operator assembly. The second motor could be mounted to the top L-shaped plate  40  of the support with the second lead screw laterally offset with respect to the first lead screw  28 . The motors would be synchronized but operated to drive the first and second lead screws in opposed directions. 
         [0034]      FIGS. 5 and 6  illustrate another example of the integration of a motorized latch actuation system  12 ′ to a double hung type casement window  10 ′ but this time for a model of window having a solid central post  22 ′ having no internal cavity in which the above described components of the motorized latching system could potentially be mounted. The only space available to access the lock bars  24 ′ is the ¾ inch to 1 inch gap existing between the central post  22 ′and the vertical moulding  23  on each side of the post  22 ′. This does not leave enough room to accommodate the motor. 
         [0035]    The motor  26 ′ had thus to be disposed in a rectangular wooden box or casing  27  mounted to the casement  16 ′ underneath sill  29 . The casing  27  forms a hollow window frame extension for receiving window operator equipment and the like. The motor  26 ′ is thus concealed in the building wall below the original window frame. The dimensions of the casing  27 , notably the height thereof, are greatly limited by the presence of the structural or skeleton members of the building wall in which the window is mounted. In view of the small space available underneath the casement window  10 ′, the motor  26 ′ is horizontally disposed in the casing  27  and a universal joint  31  is used to connect the motor  26 ′ to the lead screw  28 ′ extending vertically along the side of the central post  22 ′ in the gap defined between the side moulding  23  and the central window post  22 ′. 
         [0036]    The lead screw  28 ′ extends through a hole  33  defined in the window sill  29  and is vertically supported by a bottom support block  37  mounted to the central post  22 ′ underneath the sill of the window  10 ′. As shown in  FIG. 6 , the lead screw  28 ′ has a shoulder resting on top of the bottom block  37  to prevent the screw  28 ′ from sliding downwardly under gravity into the lead screw passage defined in the bottom block  37 . The upper end or tip of the lead screw  28 ′ is received in a hole defined in a top support  44 ′ screwed or otherwise secured to the side of the central post  22 ′. The top support  44 ′ is also contained in the gap between the post  22 ′ and the moulding  23 . 
         [0037]    The limit switches  46   a ′,  46   b ′ and  46   c ′ are also directly mounted to the side of the post  22 ′ below the internally threaded slider  30 ′ mounted on the lead screw  28 ′ in the gap between the post  22 ′ and the moulding  23 . A L-shaped triggering finger  39  extends downwardly from the slider  30 ′ for triggering the limit switches  46   a ′,  46   b ′ and  46   c ′ when the slider  30 ′ reaches the end of its stroke. 
         [0038]    The mounting of the slider  30 ′ against the side wall of the central post  22 ′ locks the slider  30 ′ against rotation and constrains the slider  30 ′to move linearly along the side wall of the post  22 ′ in response to the rotation of the lead screw  28 ′. An elongated strip or rod  41  extends upwardly from a post facing side of the slider  30 ′ in order to rigidly connect the same to the existing lock bar  24 ′ interconnecting the latches  20 ′ of the window  10 ′. The linear movement of the slider  30 ′ on the lead screw  28 ′ can thus be transferred to the existing lock bar  24 ′ in order to latch and unlatch the window. 
         [0039]    It is understood that a similar motorized latch operator is provided on the other side of the central post to operate the lock bar interconnecting the latches associated to the second window sash (not shown). 
         [0040]      FIGS. 7 and 8  illustrate another example of the integration of a motorized latch actuation system  12 ″ to an originally manually actuated latching system of a single hung type casement window  10 ″. In this example, the window lock bar  24 ″ interconnecting the latches  20 ″ on one side of the window frame is disposed further towards the outside of the room in which the window is mounted. The casing  27 ″ secured underneath the window frame in the building wall and holding the motor  26 ′ is not aligned with the lock bar  24 ″. The casing  27 ″ is located further towards the inside of the room relative to the lock bar  24 ″. As will be seen herein after, this misalignment problem is overcome by connecting the motorized system  12 ″ to an existing link  70  originally joined to the lever/handle (not shown) of the lower manual latch  20 ″. 
         [0041]    As shown in  FIG. 8 , the motor  26 ′ is horizontally mounted in casing  27 ″ which is disposed in the building wall underneath the window frame. The motor  26 ″ is drivingly connected to a vertically disposed lead screw  28 ″ via universal joint  31 ″. The lead screw  28 ″ extends through a hole defined in the window sill and has a top head  71  retained captive between a base  72  and a cover  74 . The base  72  and the cover  74  are made of a low friction material and are used to support the lead screw  28  “in position. The base  72  is mounted on a top surface of the window sill and has a through bore defined therein for allowing the lead screw  28 ” to pass therethrough. A recess is defined in a top surface of the base  72  for receiving a split washer  76 . The washer  76  is mounted about the lead screw  28 ″ underneath head  71 . The cover  74  has a recess defined in an undersurface thereof for accommodating the screw head  71  and is screwed or otherwise suitably secured to the base  72 . A horizontal moulding (not shown) covers the sill of the window to conceal the base  72  and the cover  74 . 
         [0042]    A low frictional material rectangular sleeve  78  is installed in the hole defined in the window sill to provide for smoothly guided movement of slider  30 ″ on the lead screw  28 ″. The sleeve  78  is configured to lock the slider  30 ″ against rotation while providing for smooth linear gliding movement therein. An elongated flattened rod or strip  80  is attached to the slider  30 ″ and extends vertically upwardly through aligned slotted holes defined in the base  72  and cover  74 . The upper end of the strip  80  is pivotally connected to existing link  70  which is, in turn, connected to the lock bar  24 ″ joining all the latches  20 ″ of the window. The pull and push strip  80  can be guided at the upper end thereof by a guide  82  mounted to the side member of the window frame on which the latches  20 ″ are mounted. The vertical moulding (not shown) of the side member of the window frame conceal all the mechanism disposed therealong. 
         [0043]    As shown in  FIG. 7 , the limit switches  46   a ″,  46   b ″,  46   c ″ are mounted on the side of the frame next to the upper latch  20 ″ so as to be triggered by the components thereof. 
         [0044]      FIGS. 9 to 12  illustrate another example of a motorized latch actuation system  120  adapted to be mounted in a hollow casing (not shown) secured underneath a window frame in a building wall. The system  120  comprises a support frame  136  including a base plate  136   a  adapted to be screwed or otherwise suitably securely mounted to the bottom wall of the casing underneath the window frame. The support frame  136  further comprises a pair of side plates  136   b  extending integrally upwardly from the base plate  136   a.  A lever  132  is pivotally mounted to side plates  136   b  for rotation about a generally horizontal axle  137  extending transversely through the side plates  136   b  and the lever  132 . The lever  132  has an arm portion  132   a  projecting away from one end of an inverted U-shaped end portion  132   b  mounted between the side plates  136   b  of the support frame  136 . The side plates  136   b  and the U-shaped end portion  132   b  have registering holes for receiving the axle  137 . The distal end of the arm portion  132   a  of the lever  132  has an elongated slot  132   c  ( FIG. 11 ) adapted to receive a fastener  133  for pivotal connection to a latch bar extension  141  adapted to be rigidly connected to bottom end of the latch bar (not shown) of the window. In this way, the lever  132  can be rotated about the axle  137  to linearly displace the latch bar extension  141  and, thus, the latch bar in an upward or a downward direction (see arrows A in  FIG. 11 ) in order to lock or unlock the window. The length of the arm portion (distance between the axle  137  and the elongated slot  132   c ) is selected to provide the desired levering force. 
         [0045]    As best shown in  FIGS. 9 and 11 , a pair of low friction pads  139  is fixedly mounted to the inwardly facing side of the U-shaped end portion  132   b  of the lever  132  for engagement with a slider  130  which is, in turn, threadably engaged on a lead screw  128  driven by a reversible rotary motor  126 . The slider  130  is trapped between the low friction pads  139  and has cylindrical projections  130   a  extending laterally therefrom for engagement in corresponding cylindrical holes defined in the pads  139 . This arrangement allows for relative angular movements between slider  130  and the pads  139  (and, thus, the lever  132 ) when the slider  130  moves along the lead screw  128  in response to a torque being applied thereto by the motor  126 . The distance between the cylindrical projections  130   a  of the slider  130  and the pivot axis of the lever (i.e. the axle  137 ) is also selected as a function of the desired levering force for operating the latch bar. 
         [0046]    As shown in  FIGS. 10 and 11 , the motor  126  is mounted to a support  126   a  which is, in turn, hingedly mounted to the base plate  136   a  of the support frame  136 . For instance, the support  126   a  may be rigidly connected to a first hinge plate  139   a  pivotally connected at  139   c  to a second hinge plate  139   b  fixed to the top surface of the base plate  136   a  at the rear end of the motor  126 . 
         [0047]    As shown in  FIGS. 9 and 11 , limit switches  146   a  and  146   c  are mounted to the inwardly facing surface of one of the side plates  136   b  of the support structure  136  and are disposed to be triggered by the inverted U-shaped portion  132   b  of the lever  132  when the same is pivoted by the slider  132  to its limit positions on axle  137 . 
         [0048]    In operation, the motor  126  may be powered to linearly displace the latch bar of the window between locked and unlocked positions. The rotation of the lead screw  128  causes the slider  130  to move therealong, thereby causing the lever to pivot about axle  137  has indicated arrows B in  FIG. 11 . The hinge connection between the motor  126  and the support frame  136  allows to accommodate the pivotal movement of the lever  132  and, thus, of the slider  130  relative to the axle  137 . As a result, the arm portion  132   a  of the lever  132  is pivoted as depicted by arrows C in  FIG. 11  to upwardly or downwardly linearly displace the latch bar extension  141  together with the latch bar (not show) connected thereto. 
         [0049]    It is understood that the arm portion  132   a  of the lever could extend in a direction opposite to the direction illustrated in  FIGS. 9 to 11 . That is the arm portion  132   a  could extend axially in a direction away from the motor  126  forwardly relative to the lead screw  128 . The forwardly or rearwardly projecting configuration may be selected depending on the space available in the hollow casing underneath the window frame. 
         [0050]    The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.