Abstract:
An integrated lock and tilt-latch mechanism for a sliding window including an actuator assembly operably connected by a flexible linking member to at least one tilt-latch mechanism adapted for mounting in a window sash. The actuator assembly includes a control lever that rotates a sweep cam and a selectively rotates a spool, thereby locking or unlocking the sliding window or actuating the tilt-latch mechanism. At least one biasing member causes the control lever to favor locked or unlocked positions over intermediate and tilt positions.

Description:
FIELD OF THE INVENTION 
     This invention relates to window locks, and more particularly to window locks for sliding windows. 
     BACKGROUND OF THE INVENTION 
     Double-hung and single hung sliding windows include two window sashes typically mounted for vertical movement along adjacent parallel tracks in a window frame. Traditional double-hung window designs provide poor washability, because it is difficult for a person located inside a structure in which the window is installed to wash the outside of the window pane. To fully wash the outer surface of such windows (which outer surface is the one which is most often in need of cleaning), the person cleaning the window must typically go outside the dwelling. This is not only extremely inconvenient, as the person has to walk significant distances merely to wash both sides of a single window, but it can also force a window washer, when trying to wash double and single-hung windows located at significant heights, to face the undesirable choice of either risking injury by climbing to that height or doing a relatively poor job of washing by merely reaching from a distance with a hose or a special long pole apparatus of some type. Such cleaning is still further complicated where there are screens or storm windows that must be removed prior to washing. 
     To overcome this problem, windows of this type have been developed that enables one or more of the sashes to be tilted inwardly to gain access to the outside surface of the window pane from within the structure. Various types of latching mechanisms have been developed to enable the latch to secure the sash in place in the frame, but also enable tilting the sash by operating the latches. A common arrangement has such latches positioned in opposite ends of a top horizontal rail of the upper and/or lower sash, with each latch typically including a bolt end or plunger which during normal operation extends out from the side of the sash into the sash track in the window frame to guide the sash for typical vertical movement. When washing is desired, a bolt end or plunger of each latch is retracted to free the top rail of the sash from the track so that the sash may be suitably pivoted inwardly about pivots guiding the bottom rail of the sash in the track and thereby allow the washer to easily reach the outside surface of the window pane of that sash. 
     The bolt end or plunger in many of the prior art latches is usually biased outwardly into the track by a spring structure or the like, with the bolt end retracted inwardly by the washer manually pulling the bolt ends in toward the center of the top rail against the force of the spring as, for example, in the mechanism disclosed in U.S. Pat. No. 5,139,291. A drawback of such mechanisms, however, is that both latches must be operated simultaneously, requiring that the operator use both hands. Moreover, simultaneous operation of latch controls spaced at the far edges of the sash can be awkward, especially for wide windows. Another mechanism, disclosed in U.S. Pat. No. 5,992,907, commonly owned by the owners of the present invention and hereby fully incorporated herein by reference, has a lever operably coupled with a check rail lock assembly that simultaneously operates remotely located tilt-latch assemblies. 
     Other mechanisms linking tilt latches with a single control that also locks the sashes together are well known. For example, U.S. Pat. No. 5,398,447 (the &#39;447 patent) discloses a tilt-lock latch mechanism wherein a lever positioned proximate the center of the top rail of a lower sash may be rotated in one direction to engage a keeper positioned on the upper sash proximate the lever or in the opposite direction to operate remotely located tilt latches to enable tilting of the lower sash for cleaning. U.S. Pat. No. 5,791,700 (the &#39;700 patent) discloses a tilt lock latch mechanism wherein a single control lever operates both sash locks and remote tilt latches. To accomplish this, the control lever is selectively rotatably positionable in three discrete positions: (1) a first position wherein the sash locks and the tilt latches are engaged; (2) a second position wherein the sash locks are disengaged to enable sliding of the sashes but the tilt latches are still engaged; and (3) a third position wherein the sash locks and the tilt latches are disengaged to enable sliding of the window. Similarly, U.S. Pat. No. 6,817,142 (the &#39;142 patent) and its continuation U.S. application Ser. No. 10/959,696 also disclose a tilt-lock latch mechanism having such a three-position control lever. 
     Each of the above described mechanisms, however, has certain drawbacks. The &#39;447 patent mechanism, while generally simple, requires rotation of the control lever in opposite directions from a center position for unlocking and tilting. This is inconvenient and may result in unintended tilting operation of the window if an inexperienced user seeking merely to unlock the window rotates the lever in the wrong direction. Also, the &#39;447 patent mechanism requires that a separate control be manipulated by the operator to maintain the control lever in a desired position. The &#39;700 patent mechanism, while enabling same-direction rotation of the control lever, is relatively complex, and may be expensive to manufacture and difficult to install and adjust. The &#39;142 patent mechanism may be difficult to adjust, requiring partial disassembly and manipulation of a screw on the tilt latches for tensioning the strap connecting the control lever with the tilt latches. Moreover, the &#39;142 patent describes a separate button that must be manipulated for engaging or releasing the tilt latches. This may be confusing for a user and result in frustration when attempting to tilt the window for cleaning, or in failure to properly reengage the tilt latches when cleaning is complete. 
     Another mechanism, described in U.S. Pat. No. 6,877,784, includes a rotary lever with sash lock that actuates remote tilt latches through an extensible member. A drawback of this mechanism, however, is that it is relatively complex, including a spring-loaded control lever and a pivoting trigger release mechanism in each of the tilt latches, making it relatively more expensive to produce and reducing reliability. Further, there are no simple means provided for attaching the extensible member to the tilt latches, nor is any means for adjusting length and tension of the extensible member provided. 
     U.S. patent application Ser. No. 10/289,803 discloses a similar tilt lock latch mechanism including a three-position control lever that actuates a sash lock as well as remotely located tilt latches. One drawback of this mechanism, however, is that a relatively complicated fastener arrangement is used for connecting the actuator spool to the tilt latch connector, affecting cost of manufacture and usability of the mechanism. Also, the tilt latches are not equipped with any mechanism for holding the latches in the retracted position. When the window is tilted into position after cleaning, the protruding latch-bolts may mar the window frame if the operator forgets to manually retract them. Moreover, a separate button is described that must be manipulated for engaging or releasing the tilt latches, thus complicating operation. 
     U.S. patent application Ser. No. 11/340,428 also discloses a similar tilt lock latch mechanism including a three-position control lever that actuates a sash lock as well as remotely located tilt latches. One drawback of this mechanism, however, is that the lever may remain in the window-tilt position unless an operator manually returns the lever to the locked or unlocked positions. Also, the lever may remain in an intermediate position unless an operator specifically positions the lever to a tilt, locked, or unlocked position. Moreover, it may be difficult for an operator to judge when the lever has been correctly positioned to a tilt, locked, or unlocked position. 
     What is still needed is a low-cost combination tilt-lock-latch mechanism for a double-hung window that is easy to install and adjust, simple to use, and is biased toward a locked or unlocked position. 
     SUMMARY OF THE INVENTION 
     The present invention addresses the need for a low-cost combination tilt-lock-latch mechanism for a sliding window that combines ease of installation and adjustment, simplicity of use, and a bias toward a locked or unlocked position. In embodiments of the invention, an integrated lock and tilt-latch mechanism for a sliding window includes at least one tilt-latch mechanism adapted for mounting in the window sash. The tilt-latch mechanism includes a housing presenting a longitudinal axis and having an aperture defined in a first end thereof, a plunger having a latch-bolt portion, a plunger-latch member, and first and second biasing members. The plunger is disposed in the housing and is selectively slidably shiftable along the longitudinal axis of the housing between an extended position in which the latch-bolt portion of the plunger projects through the aperture in the housing to engage the window frame so as to prevent tilting of the sash, and a retracted position in which the latch-bolt portion of the plunger is substantially within the housing to enable tilting of the sash. The first biasing member is arranged so as to bias the plunger toward the extended position. The plunger-latch member is operably coupled with the tilt-latch housing and is arranged so as to be selectively slidably shiftable in a direction transverse to the longitudinal axis when the plunger is in the retracted position. The plunger-latch member is shiftable between a first position in which the plunger-latch member engages and prevents shifting of the plunger and a second position in which the plunger-latch member enables shifting of the plunger. The second biasing member is arranged so as to bias the plunger-latch member toward the first position so that when the plunger is retracted, the plunger-latch automatically shifts to retain the plunger in the retracted position. The plunger-latch may include a trigger portion arranged so that when the sash is tilted into position in the frame, the trigger portion contacts the window frame or second sash, shifting the plunger-latch so as to release the plunger. The mechanism further includes an actuator mechanism adapted for mounting on the sash. The actuator mechanism includes a housing, a control on the housing, a lock member, and a tilt-latch actuator member. The lock member and the tilt-latch actuator member are operably coupled with the control. A linking member operably couples the tilt-latch actuator member and the plunger of the tilt-latch mechanism. The control lever is selectively positionable between at least three positions, including a locked position in which the sweep cam is positioned so that a portion of the sweep cam extends under the locking tab of a keeper, an unlocked position in which the sweep cam is substantially retracted from the locking tab of a keeper, and a tilt position in which the sweep cam is retracted and the plunger of the tilt-latch mechanism is positioned in the retracted position. 
     In another embodiment of the invention, an integrated lock and tilt-latch mechanism for a sliding window having a frame with at least one sliding sash therein, the sash also tiltably positionable relative to the frame, includes an actuator assembly, at least one tilt-latch assembly adapted for mounting on the sash, and a flexible linking member. The actuator assembly includes a housing, a control lever, a lock member, and a tilt-latch actuator member. The lock member and the tilt-latch actuator member are operably coupled with the control, and the tilt-latch actuator has structure for receiving and applying tension to the flexible linking member. The at least one tilt-latch assembly includes a tilt-latch housing presenting a longitudinal axis and having an aperture defined in a first end thereof. A plunger is disposed in the tilt-latch housing, the plunger having a latch-bolt portion and being selectively slidably shiftable along the longitudinal axis between an extended position in which the latch-bolt portion of the plunger projects through the aperture and a retracted position in which the latch-bolt portion of the plunger is substantially within the tilt-latch housing. The plunger defines a channel for receiving the flexible linking member and has a locking member positioned proximate the channel. The locking member is selectively shiftably adjustable from a location outside the tilt-latch housing between a first position in which the flexible linking member is freely slidable in the channel to enable insertion and removal of the flexible linking member, and a second position in which the locking member is engaged with the flexible linking member to fixedly secure the flexible linking member in the channel, thereby operably coupling the tilt-latch actuator with the plunger of the tilt-latch. In a further embodiment of the invention, a window includes a frame and a first sash and a second sash, each slidable in the frame. The first sash is also tiltably positionable relative to the frame. An integrated lock and tilt-latch mechanism is positioned on the first sash, including an actuator mechanism, at least one tilt-latch adapted for mounting on the sash, and a flexible linking member. The actuator mechanism includes a housing, a control, a lock member, and a tilt-latch actuator member. The lock member and the tilt-latch actuator member are operably coupled with the control. The tilt-latch actuator has structure for receiving and applying tension to the flexible linking member. The at least one tilt-latch includes a tilt-latch housing presenting a longitudinal axis and having an aperture defined in a first end thereof, and a plunger disposed in the tilt-latch housing. The plunger has a latch-bolt portion and is selectively slidably shiftable along the longitudinal axis between an extended position in which the latch-bolt portion of the plunger projects through the aperture and a retracted position in which the latch-bolt portion of the plunger is substantially within the tilt-latch housing. The plunger defines a channel for receiving the flexible linking member and has a locking member positioned proximate the channel. The locking member is selectively shiftably adjustable, from a location outside the tilt-latch housing, between a first position in which the flexible linking member is freely slidable in the channel to enable insertion and removal of the flexible linking member, and a second position in which the locking member is engaged with the flexible linking member to fixedly secure the flexible linking member in the channel, thereby operably coupling the tilt-latch actuator with the plunger of the tilt-latch. The control is selectively positionable between at least three positions, including a locked position in which the lock member is positioned so that a portion of the lock member extends from the housing of the actuator mechanism, an unlocked position in which the lock member is positioned substantially within the housing of the actuator mechanism, and a tilt position in which the lock member is positioned substantially within the housing of the actuator mechanism and the plunger of the tilt-latch mechanism is positioned in the retracted position. 
     In yet another embodiment of the invention, a window includes a frame and a first and a second sash, each sash slidable in the frame, wherein the first sash is also tiltably positionable relative to the frame. An integrated lock and tilt-latch mechanism is positioned on the first sash, the mechanism including at least one tilt-latch mechanism having a housing presenting a longitudinal axis, a plunger having a latch-bolt portion, a plunger-latch member, and first and second biasing members. The plunger is disposed in the housing and is selectively slidably shiftable along the longitudinal axis between an extended position in which the latch-bolt portion of the plunger engages the frame of the window to prevent tilting of the first sash and a retracted position in which the latch-bolt portion of the plunger is substantially within the housing to enable tilting of the first sash. The first biasing member is arranged so as to bias the plunger toward the extended position. The plunger-latch member is operably coupled with the housing and arranged so as to be selectively slidably shiftable in a direction transverse to the longitudinal axis when the plunger is in the retracted position. The plunger-latch member is shiftable between a first position in which the plunger-latch member engages and prevents shifting of the plunger and a second position in which the plunger-latch member enables shifting of the plunger. The second biasing member is arranged so as to bias the plunger-latch member toward the first position. The mechanism further includes an actuator mechanism including a housing, a control on the housing, a lock member, and a tilt-latch actuator member. The lock member and the tilt-latch actuator member are operably coupled to the control with a linking member operably coupling the tilt-latch actuator member and the plunger of the at least one tilt-latch mechanism. The control is selectively positionable among at least three positions, including a locked position in which a sweep cam is engaged with a keeper of the second sash to prevent relative sliding movement of the first and second sashes, an unlocked position in which the lock member is free from the keeper of the second sash, and a tilt position in which the lock member is free from the keeper of the second sash and the plunger of the tilt-latch mechanism is positioned in the retracted position to enable tilting of the first sash. 
     In another embodiment, the control lever is biased toward a locked position or an unlocked position. The sweep cam of the control lever is selectively shiftably adjustable from between a first position in which the flexible linking member is freely slidable in the channel to enable insertion and removal of the flexible linking member, and a second position in which the locking member is engaged with the flexible linking member to fixedly secure the flexible linking member in the channel, thereby operably coupling the tilt-latch actuator with the plunger of the tilt-latch. The control lever is selectively positionable between at least three positions including a locked position in which the sweep cam engages a keeper, an unlocked position in which the sweep cam is disengaged from the keeper, and a tilt position in which the sweep cam is disengaged from the keeper and the plunger of the tilt-latch mechanism is positioned in the retracted position. Depending upon the position of the control lever, the control member is biased toward the locked position or the unlocked position. In the tilt position and intermediate the tilt position and the unlocked position, the control is biased toward the unlocked position. Intermediate the unlocked position and the locked position, the control is biased toward the unlocked position or the locked position, dependent on which position the control is most proximate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 2  is a top view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 3  is a side view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 4  for a rear view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 5  is a side view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 6  is a front view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 7  is a perspective view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 8  is a top view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 9  is a side view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 10  is a rear view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 11  is a side view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 12  is a front view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 13  is a perspective view of a double-hung window with an integrated lock and tilt-latch assembly according to an embodiment of the present invention; 
         FIG. 14  is a perspective view of a window sash with an integrated lock and tilt-latch assembly according to an embodiment of the present invention; 
         FIG. 15  is a perspective view of a window sash with an actuator assembly according to an embodiment of the present invention; 
         FIG. 16  is an exploded perspective view of an actuator assembly according to an embodiment of the present invention; 
         FIG. 17  is a sectional perspective view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 18  is a sectional perspective view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 19  is a sectional perspective view of an actuator assembly in a locked position according to an embodiment of the present invention; 
         FIG. 20  is sectional perspective view of an actuator assembly in an unlocked position according to an embodiment of the present invention; 
         FIG. 21  is a sectional perspective view of an actuator assembly in a tilt position according to an embodiment of the present invention; 
         FIG. 22  is an exploded view of a tilt-latch assembly according to an embodiment of the invention; 
         FIG. 23  is an exploded view of a tilt-latch assembly according to another embodiment of the invention; 
         FIG. 24  is a cross-sectional view of the plunger portion of a tilt-latch assembly taken at Section  7 - 7  of  FIG. 23 ; 
         FIG. 25  is a perspective view of a first portion of the housing of the tilt-latch assembly of  FIG. 23 ; 
         FIG. 26  is a side elevation view of the housing portion depicted in  FIG. 25 ; 
         FIG. 27  is a perspective view of a second portion of the housing of the tilt-latch assembly of  FIG. 23 ; 
         FIG. 28  is a side elevation view of the housing portion depicted in  FIG. 27 ; 
         FIG. 29  is an exploded view of a tilt-latch assembly according to an embodiment of the invention; 
         FIG. 30  is an exploded view of the tilt-latch portion of an integrated lock and tilt-latch assembly according to an embodiment of the present invention; 
         FIG. 31  is a perspective view of a tilt-latch assembly according to an embodiment of the invention with the housing depicted in phantom to reveal structures enabling locking of a linking member from outside the housing with a wrench; 
         FIG. 32  depicts the tilt-latch assembly of  FIG. 31  with the Allen wrench engaged with the locking cam member; 
         FIG. 33  is a perspective view of a tilt-latch assembly according to an embodiment of the invention with the housing depicted in phantom revealing the linking-member passage and locking member prior to locking of the linking member; 
         FIG. 34  depicts the tilt-latch assembly of  FIG. 33  with the locking cam member positioned to lock the linking member to the plunger. 
         FIG. 35  is a cross-sectional view of a plunger showing how a linking member is terminally attached according to an alternative embodiment of the invention; 
         FIG. 36  is a top view of the plunger depicted in  FIG. 35 ; 
         FIG. 37  is a bottom view of the plunger depicted in  FIG. 35 ; 
         FIG. 38  is a perspective view of the plunger depicted in  FIG. 35 ; 
         FIG. 39  is a cross-sectional view of a plunger showing how a linking member is terminally attached according to an embodiment of the invention; 
         FIG. 40  is a top view of the plunger depicted in  FIG. 39 ; 
         FIG. 41  is a bottom view of the plunger depicted in  FIG. 39 ; 
         FIG. 42  is a perspective view of the plunger depicted in  FIG. 39 ; 
         FIG. 43  is a cross-sectional view of a U-shaped component used to terminally attach a flexible linking member to the plunger depicted in  FIG. 39 ; 
         FIG. 44  is a cross-sectional view of a plunger showing how a linking member is terminally attached according to an alternative embodiment of the invention; 
         FIG. 45  is a top view of the plunger depicted in  FIG. 44 ; 
         FIG. 46  is a top view of the plunger depicted in  FIG. 44 ; 
         FIG. 47  is a perspective view of the plunger depicted in  FIG. 44 ; 
         FIG. 48  is a cross-sectional view of a plunger showing how a linking member is terminally attached according to an alternative embodiment of the invention; 
         FIG. 49  is a top view of the plunger depicted in  FIG. 48 ; 
         FIG. 50  is a bottom view of the plunger depicted in  FIG. 48 ; and 
         FIG. 51  is a perspective view of the plunger depicted in  FIG. 48 . 
         FIG. 52  is a front view of a base housing of a base assembly according to an embodiment of the present invention. 
         FIG. 53  is a top view of a base housing of a base assembly according to an embodiment of the present invention. 
         FIG. 54  is a bottom view of a base housing of a base assembly according to an embodiment of the present invention. 
         FIG. 55  is a perspective view of a base housing of a base assembly according to an embodiment of the present invention. 
         FIG. 56  is a side view of a base housing of a base assembly according to an embodiment of the present invention. 
         FIG. 57  is a top view of a control lever of an actuator assembly according to an embodiment of the present invention. 
         FIG. 58  is a bottom view of a control lever of an actuator assembly according to an embodiment of the present invention. 
         FIG. 59  is a rear view of a control lever of an actuator assembly according to an embodiment of the present invention. 
         FIG. 60  is a side view of a control lever of an actuator assembly according to an embodiment of the present invention. 
         FIG. 61  is a perspective view of a control lever of an actuator assembly according to an embodiment of the present invention. 
         FIG. 62  is a top view of a baseplate of a base assembly according to an embodiment of the present invention. 
         FIG. 63  is a side view of a baseplate of a base assembly according to an embodiment of the present invention. 
         FIG. 64  is a perspective view of a baseplate of a base assembly according to an embodiment of the present invention. 
         FIG. 65  is a top view of a gear of a base assembly according to an embodiment of the present invention. 
         FIG. 66  is bottom view of a gear of a base assembly according to an embodiment of the present invention. 
         FIG. 67  is a perspective view of a gear of a base assembly according to an embodiment of the present invention. 
         FIG. 68  is a side view of a gear of a base assembly according to an embodiment of the present invention. 
         FIG. 69  is a side view of a spool of a base assembly according to an embodiment of the present invention. 
         FIG. 70  is a perspective view of a spool of a base assembly according to an embodiment of the present invention. 
         FIG. 71  is a bottom view of a spool of a base assembly according to an embodiment of the present invention. 
         FIG. 72  is a top view of a spool of a base assembly according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Locking tilt-latch assembly  100  is generally mounted onto double-hung window, as depicted in  FIG. 13 . As depicted in  FIG. 14 , locking tilt-latch assembly  100  generally includes actuator assembly  102 , tilt-latch assemblies  104 , and linking member  106 . Actuator assembly  102  generally includes base assembly  108  and control lever  110 . Base assembly  108  is defined by baseplate  112  and base housing  114 . In an example embodiment, baseplate  112  and base housing  114  are assembled together such that baseplate  112  defines the top of base assembly  108 , as depicted in  FIG. 15 . Control lever  110  has handle  116 , sweep cam  118 , and shank  120 . Sweep cam  118  is generally tapered away from handle  116 . As control lever  110  rotates, sweep cam  118  engages or disengages keeper  122 . When control lever  110  is in a locked position, as depicted in  FIG. 15 , sweep cam  118  is positioned under and within locking tab  124  of keeper  122 . Inside sash  310  of double-hung sash window  312  is thereby substantially prevented from being raised relative to frame  334 . 
     Control lever  110  is coupled to base housing  114  through shank-receiving aperture  126 . Shank-receiving aperture  126  receives shank  120  of lever  110  therethrough. Shank  120  defines upper portion  128 , lower portion  130 , and middle portion  132 . Upper portion  128  is generally cylindrical in shape. Upper portion  128  defines mating cylinder  134  with lateral surface  134 A and outer edge  134 B. Stop  136  is located on outer edge  138 A of mating cylinder  134 . Middle portion  132  is generally quadrangular in shape. Middle portion  132  forms cam  158  that may be trapezoidal in shape with acute corners  158 A-B and obtuse corners  158 C-D, as depicted in  FIGS. 19-21 . Lower portion  130  is generally cylindrical in shape. Lower portion  130  forms multi-level protrusions  138 . Large-diameter protrusion  138 A extends outwardly from cam  158 , while small-diameter protrusion  138 B extends outwardly from large-diameter protrusion  138 A. Lip  139  is formed where large-diameter protrusion  138 A and small-diameter protrusion  138 B meet. Retainer  156  is received on small-diameter protrusion  138 B of lower portion  130  of shank  120 . Retainer  156  retains baseplate  112  and lever  110  on base housing  114  so that control lever  110  is rotatable about axis A-A relative to base housing  114 , as annotated in  FIG. 14 . 
     As depicted in  FIGS. 14-18 , base assembly  108  generally includes baseplate  112 , base housing  114 , retainer  156 , gear  160 , spool  162 , and biasing member  164 . Underside  170  of base housing  114  defines recesses. The recesses include deep recess portion  173  and shallow recess portion  174 . Underside  170  has upper ceiling  177 A, lower ceiling  177 B, and edge  181 . The recesses receive middle portion  132  and lower portion  130  of shank  120 , gear  160 , a portion of spool  162 , and biasing member  164 . Upper ceiling  177 A defines deep recess portion  173  and lower ceiling  177 B defines shallow recess portion  174 . Deep recess portion  173  has main recess portion  173 A and side recess portions  173 B-C. Edge  181 , deep recess wall  183 , and shallow recess wall  185  define the shape of deep recess portion  173  and shallow recess portion  74 . Deep recess portion  173  is shaped conformingly to, and receives baseplate  112 . The plane formed by edge  181  of base housing  114  defines the lower planar boundary of underside  170 . 
     Extending downward from lower ceiling  177 B are recess posts  140 . Recess posts  140  generally are integral with upper ceiling  177 A and lower ceiling  177 B and do not extend beyond the plane formed by edge  181  of base housing  114 . Recess posts  140  have main support sections  142  and support surfaces  143 . Support surfaces  143  of recess posts  140  are substantially coplanar. Support posts  140 A-B proximal to spool post  190  may have tip sections  144 . When baseplate  112  is situated on recess posts  140  in deep recess portion  173 , tip sections  144  resist lateral movement of baseplate  112 . Lateral surface of tip sections  144  and edge  181  of base housing  114  are generally coplanar. Inner edges  146  of supports posts  140  and upper recess wall  183  are also generally coplanar. Inner edges  146  are substantially perpendicular to upper ceiling  177 AA and lower ceiling  177 B. Outer edges  148  of recess posts  140  are also substantially perpendicular to upper ceiling  177 AA and lower ceiling  177 B. 
     Also extending downward from lower ceiling  177 B are mounting posts  186 . Mounting posts define apertures  194  extending from underside  170  to top surface  178  of base housing  114 . Apertures  194  receive fastening members which may be used to secure base assembly  108  to top surface  316  of double hung sash window  312 . 
     Referring to  FIGS. 17-21 , biasing member  164  is secured in deep recess portion  173  between recess posts  140 . Biasing member may be any number of flexible materials possessing shape memory characteristics, such as, for example, a spring in the geometry depicted in an example embodiment of the present invention or in a variety of other geometries that would impart biasing upon cam followers  219  or gear  160  and cam  158 . Cam  158  and cam followers  219  are situated between flex regions  150 ,  152  of biasing member  164 . Flex regions  150 ,  152  extend through main recess portion  173 A and into side recess portions  173 B,C. Generally, the distance between flex regions  150 ,  152  is approximately the distance between obtuse corners  158 A,B of cam  158 . In the embodiment depicted in  FIG. 16 , biasing member  164  also has curved joining region  154 . Although only one biasing member  164  is depicted in  FIGS. 16-21 , alternative embodiments may include a pair of separate biasing members  164  — each biasing member  164  providing a separate flex region  150  or  152  — secured in deep recess portion  173  between recess posts  140 . 
     Shank-receiving aperture  126  extends from deep recess portion  173  to top surface  178  of base housing  114 . A boss (not shown) surrounds shank-receiving aperture  176  on top surface  178  of base housing  114 . The boss defines a semi-circular inner recess (not shown) around shank-receiving aperture  176 . The semi-circular inner recess (not shown) intersects an inner edge (not shown) of shank-receiving aperture  176 . Stop  136  outer edge  134 B of mating cylinder  134  of shank  120  is received in semi-circular inner recess  182 . Stop  136  is situated substantially within the semi-circular inner recess. When upper portion  128  is positioned within shank-receiving aperture  176 , the semi-circular inner recess forms a channel defined by outer edge  134 B of mating cylinder  134  of shank  120  and the inner edge of the boss. The length of the semi-circular inner recess thereby limits the rotation of control lever  110  about axis A-A relative to base housing  114 . 
     Spool post  190  projects downwardly from underside  170  of base housing  114 . Spool post  190  generally is formed from wall  191  defining aperture  192 . Aperture  192  is aligned in the longitudinal direction of base housing  114 . Aperture  192  extends outwardly from underside  170  of base housing  114 . Spool post  190  may also be a solid post such that spool post  190  does not have an aperture. 
     As depicted in  FIG. 16 , baseplate  112  generally has main portion  198  defining aperture  200 , recessed retainer-holding area  202 , semi-circular receiving opening  204 , and alignment lugs  206 . Baseplate  112  also has ears  208 . Aperture  200  receives lower portion  130  of shank  120 . Retainer  156  can be situated in recessed retainer-holding area  202 . When retainer  156  is situated in recessed retainer-holding area  202 , bottom surface  199  of main portion  198  and bottom surface  156 A of retainer  156  are substantially coplanar. Semi-circular receiving opening  204  receives spool  162 . Alignment lugs  206  extending downward at or near the perimeter of semi-circular receiving opening  204  to substantially retain spool  162  in the longitudinal direction of base housing  114 . 
     Gear  160  has non-gear segment  210 , gear hole  212 , and gear segment  214  extending radially from gear hole  212 , as depicted in  FIG. 16 . Gear segment  214  is formed in outer wall  221  of gear  160 . Gear  160  has a top surface (not shown) opposite bottom surface  218 . The top surface and bottom surface  218  are substantially parallel with upper ceiling  177 AA and lower ceiling  177 B. The top surface generally has recessed region (not shown). Extending upward from the top surface and the recessed region are cam followers  219 . Circumference of recessed region  120  is substantially circular. The diameter of the recessed region is substantially the same as the linear distance between acute corners  158 A-B of cam  158  such that cam  158  fits within the recessed region. The linear distance between tips  219 A of cam followers  219  is greater than the linear distance between obtuse corners  158 C-D of cam  158 . 
     Gear  160  is rotatably received in deep recess portion  173  of underside  170  of base housing  114 . Bottom surface  218  faces downward and the top surface faces upward. Gear segment  214  faces toward spool post  190  and non-gear segment  210  faces away from spool post  190 . Shank  120  of control lever  110  extends through gear hole  212  of gear  160 . Lower portion  130  extends through gear hole  212  such that both large-diameter protrusion  138 A and small-diameter protrusion  138 B extend downward through gear hole  212  past bottom surface  218 . Generally, shank  120  of control lever  110  is inserted through aperture  126  of base housing  114  and lower portion  130  of shank  120  is inserted through gear hole  212  of gear  160 . Cam followers  219  occupy the space between acute corners  158 A,B of cam and opposite biasing members  164 , as depicted in  FIG. 17-21 . Lateral surfaces (not shown) of cam followers  219  coextensively interact with upper ceiling  177 A and lateral surface  134 A of mating cylinder  134 . 
     Spool  162  generally includes lower portion  380  and upper portion  382 , as depicted in  FIG. 16 . Lower portion  380  defines slots  384  extending upwardly from bottom edge  385 . Slots  384  may have chamfered edges  386 . Lower portion  380  may be tapered such that the circumference of lower portion  380  decreases toward lower portion  380 . Upper portion  382  defines gear sector  388 . Gear sector  388  is formed in a portion of top edge  166  of upper portion  382  and matingly engages gear segment  214  of gear  160 . Between lower portion  380  and upper portion  382  is spool lip  390 . Spool lip  390  presents a raised edge that circumferentially extends beyond lower portion  380  and upper portion  382 . 
     Spool  162  is rotatably received by semi-circular receiving opening  204  of baseplate  112  and rotatably positioned over spool post  190 . Lower portion  380  of spool  162  extends below baseplate  112  and upper portion  382  of spool  162  extends above baseplate  112  proximate the lower surface of spool lip  390 . Alignment lugs  206  stabilize spool  162  on spool post  190 . Alignment lugs  206  also present a barrier that prevents spool lip  390  from passing through semi-circular receiving opening  204 . With baseplate  112  secured in place by retainer  156 , spool  162  is secured in place from above by lower ceiling  177 B and from below by semi-circular receiving opening  204 . Movement of spool  162  is thereby substantially limited to rotational movement around spool post  190 . 
     Gear  160  and spool  162  are desirably made from easily moldable, durable polymer material such as acetal or nylon. Control lever  110  and base housing  114  are preferably cast from suitable metallic material such as zinc alloy. Baseplate  112  and biasing member  164  are preferably die cut or stamped from metallic sheet material. Any of the above components, however, may be made from any other suitable material such as polymer or metal. In the depicted embodiments, actuator assembly  102  is easily assembled by mating control lever  110  and base housing  114 . Biasing member  164  may then be placed in deep recess portion  173  between side recess portions  173  B,C about obtuse corners  158  C,D of cam  158 . With control lever  110  positioned in an unlocked position, lower portion  130  of shank  120  may receive gear  160  such that gear segment  214  faces spool post  190  and cam followers  219  are situated between biasing members  164 . Upper portion  382  of spool  162  is positioned about spool post  190  so that gear sector  388  of spool  162  matingly engages gear segment  214  of gear  160  and slots  384  are aligned parallel to flexible linking member  106 . Baseplate  112  is positioned such that semi-circular recess  182  receives spool  162 , spool  162  enters baseplate  112  from the top surface (not shown) and exits bottom surface  199  of baseplate  112 . Aperture  200  of baseplate  112  receives lower portion  130  of shank  120 . Ears  208  of baseplate  112  rest between recess posts  140  on support surfaces  144  of recess posts  140 . Retainer  156  is assembled to small-diameter protrusion  138 B within recessed retainer-holding area  202  and mechanically secured with a fastening member, such as, for example, a stake or spinning apparatus in example embodiments. Retainer  156  is pushed or pressed about small-diameter protrusion  138 B with locking tab features so as to be secured within recessed retainer-holding area  202 . 
     Referring to  FIG. 17-21 , underside  170  of actuator assembly  102  is shown with control lever  110  in locked ( FIGS. 17-19 ), unlocked ( FIG. 20 ), and tilt ( FIG. 21 ) positions. Although the following description of how actuator assembly  102  functions is made in relation to the orientation of actuator assembly  102  depicted in the figures, it should be understood that directional descriptions would be reversed when actuator assembly  102  is installed and underside  170  is facing downward. For example, clockwise rotation of spool  162  in relation to the orientation of actuator assembly  102  depicted in  FIGS. 17-21  corresponds to counter-clockwise rotation of control lever  110  in actuator assembly  102  installed on top surface  316  of double hung sash window  312 . 
     Referring to  FIGS. 17-19 , control lever  110  is in a locked position. In the locked position, handle  116  is approximately in an nine-o&#39;clock position and acute corners  158 A, B of cam  158  are approximately in a ten-o&#39;clock-to-four-o&#39;clock position. The position of control lever  110  depicted in  FIGS. 17-19  is in the same locked position occupied by control lever  110  depicted in  FIG. 15 , which illustrates an installed tilt lock latch assembly  100 . The resiliency of biasing member  164  substantially maintains cam  158  in place so that control lever  110  remains in the locked position. 
     To disengage sweep cam  118  from keeper  122 , control lever  110  is rotated in a clockwise direction to an unlocked position, as depicted in  FIG. 20 . In the unlocked position, control lever  110  is approximately in a two-o&#39;clock position and acute corners  158 A, B of cam  158  are approximately in a two-o&#39;clock-to-eight-o&#39;clock position. By rotating control lever  110  in a clockwise direction, cam  158  is able to rotate between cam followers  219  without rotationally engaging gear  160 . Since gear  160  remains rotationally stationary as control lever  110  is rotated from the locked position to the unlocked position, spool  162  is not rotationally actuated. 
     Referring to  FIGS. 17-19 , control lever  110  is shown in the locked position with sweep cam  118  positioned so as to engage keeper  122 . Cam  158  is positioned between flex regions  150 ,  152  of biasing member  164 . In other embodiments, cam  158  is positioned between two substantially parallel biasing members  164 . When control lever  110  is in the locked position, biasing member  164  restrains cam  158  rotationally and is neutrally biased, exerting no biasing force on cam  158 , as depicted in  FIGS. 17-19 . Thus, biasing member  164  provides a favored position for control lever  110  in the locked position. 
     If cam  158  is rotated clockwise as depicted in  FIGS. 17-19  (from a normal, or overhead, view as depicted in  FIG. 15 , the direction would be reversed), however, biasing member  164  will be biased in deformation and will exert a steadily increasing biasing force in an opposite, or a counter-clockwise, direction. This counter-clockwise biasing force serves as a “soft” rotational stop for cam  158  in the clockwise rotational direction from the locked position. Cam  158  is substantially prevented from counter-clockwise rotation from locked position by stop  136 , which impedes counter-clockwise rotation from the locked position upon reaching the end of semi-circular recess  182  of base housing  114 . 
     If control lever  110  is rotated further in the clockwise direction, cam  158  can be positioned so that the biasing force exerted by biasing member  164  is directed through the center of cam  158 . In this intermediate position, which can include a range of rotational travel, biasing member  164  exerts little or no rotational biasing force on cam  158 . Rather, biasing member  164  restrains cam  158  between the locked and unlocked positions. In the intermediate position, sweep cam  118  may partially engage keeper  122 . The range in which cam  158  is restrained in the intermediate position is substantially determined by the biasing force of biasing member  164  and the shape of cam  158 . The corners  158 A-D of cam  158  can be rounded to eliminate or minimize the movement-deadening effect on cam  158  of the intermediate position. In an example embodiment, corners  158 A-D of cam  158  are sounded so as to have substantially similar radii of curvature. 
     As control lever  110  is further rotated in the clockwise direction past the intermediate position, biasing member  164  exerts a biasing force, now urging cam  158  in the clockwise direction. The rotational biasing force exerted by biasing member  164  steadily decreases as biasing member  164  returns to form. Once cam  158  reaches the unlocked position as shown in  FIG. 20 , biasing member  158  again reaches a neutral position and exerts no rotational biasing force in either direction. Thus, biasing member  164  has another favored position in the unlocked position. As before, if cam  158  is rotated further clockwise from this neutral position, biasing member  164  is loaded in deformation and exerts a steadily increasing rotational biasing force urging cam  158  and cam followers  21  counter-clockwise with a higher force than previously experienced due to the increased deformation caused by the addition of cam followers  219 . Therefore, when control lever  110  is further rotated in the clockwise direction to a tilt position, as depicted in  FIG. 21 , and then released the biasing force of biasing member  164  on cam  158  and cam follower  219  returns control lever  110  and cam  158  to the unlocked position. 
     To tilt inside sash  310  of double-hung sash window  312 , control lever  110  is rotated in a clockwise direction to a tilt position, as depicted in  FIG. 21 . In the tilt position, handle  116  is approximately in a three-o&#39;clock position and acute corners  158 A,B of cam  158  are approximately in a four-o&#39;clock-to-ten-o&#39;clock position. By continuing to rotate control lever  110  in a clockwise direction, the rotation of cam  158  causes acute corners  158 A,B to rotate cam followers  219  of gear  160  in a clockwise direction. As gear  160  rotates, gear segment  214  rotationally engages gear sector  388  of spool  162 . Since gear  160  rotates in a clockwise direction, spool  162  is caused to rotate in a counter-clockwise direction. As cam  158  rotates in a clockwise direction from the unlocked position to the tilt position, biasing member  164  exerts parallel forces on cam followers  219  that increasingly resist clockwise rotation of gear  160 . As depicted in  FIG. 21 , the continued clockwise rotation of control lever  110  and cam  158  past the tilt position when control lever  110  is fully in the tilt position is impeded by stop  136 , which impedes clockwise rotation from the tilt position upon reaching the end of semi-circular recess  182  of base housing  114 . The position of stop  136  in relation to gear segment  214  also prevents the cam  158 -cam followers  219  combination from reaching or passing the directional fulcrum created by the forces exerted by biasing member  164  on cam followers  219 . Therefore, at any point between the unlocked position and the tilt position, control lever  110  will return to the unlocked position if an operator removes the rotational force from control lever  110 . 
     As depicted in  FIGS. 22-50 , each tilt-latch assembly  104  generally includes housing  220 , plunger  222 , primary spring  224 , plunger-latch  226 , latch spring  228 , and locking cam  230 . Housing  220 , generally includes barrel portion  232  and face plate  234 . In embodiments of the invention as depicted, for example, in  FIGS. 5 ,  6 ,  8 - 11 , and  13 , housing  220  may be formed in two sections  236 ,  238 , which mate along the longitudinal axis of housing  220 . In these embodiments first housing section  236  has projecting hooks  240 , which engage shoulder structures  242  of second housing section  238  to secure the two sections  236 ,  238 , together. Second housing section  238  may also have locating pins  244 , which are received in recesses  246  to inhibit relative movement between the sections  236 ,  238 . 
     Plunger  222  generally includes latch-bolt portion  248 , central body portion  250 , and tail portion  252 . End  253  of latch-bolt portion  248  is tapered from leading edge  253 A to shoulder  253 B. Channel  254  extends axially from end  256  through tail portion  252 . Central body portion  250  defines lock cavity  258  which includes a first portion  260  extending longitudinally within plunger  222 , and a second portion  262  extending transversely to first portion  260 . Channel  254  continues axially from tail portion  252  through second portion  262  of lock cavity  258 , and emerges at outer surface  264  of central body portion  250  proximate shoulder  253 B of latch-bolt portion  248 . 
     Plunger  222  is received in barrel portion  232  of housing  220  with latch-bolt portion  248  extending through conformingly shaped aperture  266  defined by face plate  234 . Primary spring  224  is received over tail portion  252  and bears against back wall  268  of housing  220  and central body portion  250  to bias plunger  222  toward face plate  234 . 
     Locking cam  230  generally includes axle portion  270  and radial protrusion  272 . End  274  of axle portion  270  has hex socket  276  adapted to receive an Allen wrench of standard dimension. Locking cam  230  is received in lock cavity  258  with axle portion  270  extending axially and rotatable within first portion  260  and radial protrusion  272  within second portion  262 . Bore  278  is axially aligned with axle portion  270  and extends from first portion  260  of lock cavity  258  through to front end  280  of central body portion  250  proximate face  282  of latch-bolt portion  248 . Adjustment latch arm  284  extends rearwardly from front wall  286  of central body portion  250 , and includes angled portion  288  which intersects bore  278  and laterally projecting tab  290  at end  292 . 
     Plunger-latch  226  has plate portion  294  defining aperture  296  which is conformingly shaped with the cross-section of latch-bolt portion  248 . Trigger portion  298  extends from plate portion  294  and has bent end portion  300 . Plate portion  294  is slidingly received in transverse slot  302  in face plate  234 . Latch spring  228  is received in recess  304  and bears against edge  306  of plate portion  294  to bias plunger-latch  226  in the direction of trigger portion  298 . 
     In embodiments of the invention housing  220  and plunger  222  of locking tilt-latch assembly  100  are made from low-cost, easily formable acetal polymer material. These components, however, may also be made from any material having sufficient strength and suitable durability characteristics. Primary spring  224 , plunger-latch  226 , latch spring  228 , and locking cam  230  are desirably made from metallic material, but may also be made from any other suitable material. In the depicted embodiments, locking tilt-latch assembly  100  may be easily assembled by first assembling plunger-latch  226  and latch spring  228  with separate housing sections  236 ,  238 , and locking cam  230  and primary spring  224  with plunger  222 . Plunger  222  may then be placed in one of housing sections  236 ,  238 , and the housing sections snapped together by mating projecting hooks  240  with shoulder structures  242  and locating pins  244  with recesses  246 . 
     Referring to  FIG. 13 , locking tilt-latch assembly  100  is received in top rail  308  of inside sash  310  of a double-hung sash window  312 . Top rail  308  generally has a cavity (not shown) defined in top surface  316  for receiving base assembly  108  with spool  162  disposed in lower cavity portion  318 . A lateral bore (not shown) extends between the side faces (not shown) of top rail  308  and intersects the lower cavity portion. 
     Locking tilt-latch assembly  100  may be assembled by linking each of two tilt-latch assemblies  104  disposed in the lateral bore of the window  312  with linking member  106 , and placing actuator assembly  102  in the cavity to engage linking member  106  with spool  162 . Linking member  106  is preferably formed from a suitable stretch-resistant flexible polymer material. Linking member  106  is engaged with the first tilt latch assembly by inserting an Allen wrench through bore  278  and engaging hex socket  276  of locking cam  230  as depicted in  FIGS. 34-35 . As the Allen wrench is inserted, it forces adjustment latch arm  284  outwardly toward barrel portion  232  of housing  220 , engaging tab  290  in aperture  326  to lock plunger  222  axially within housing  220  as the adjustment is made. Once engaged in hex socket  276 , the Allen wrench is rotated to rotate locking cam  230  so that radial protrusion  272  is clear of channel  254 . An end  328  of linking member  106  is then inserted in channel  254  at end  256  and threaded through channel  254  until it extends from housing  220  proximate latch-bolt portion  248  as depicted in  FIG. 42 . The Allen wrench is then rotated in the opposite direction as depicted in  FIG. 43  to rotate locking cam  230  so that radial protrusion  272  forces linking member  106  into second portion  262  of lock cavity  258 . In this position, linking member  106  is frictionally locked within and secured to plunger  222 . The Allen wrench is then withdrawn from bore  278 , enabling tab  290  to recede from aperture  326 . Excess linking member  106  may then be trimmed off flush with face plate  234 . 
     With the first tilt-latch assembly  104  disposed in, and linking member  106  extending through, lateral bore  320  and trigger portion  298  facing outer sash  327 , linking member  106  may be engaged with the second tilt-latch assembly  104  by the same process as described above. With the second tilt-latch assembly  104  disposed in lateral bore  320  with trigger portion  298  facing outer sash  327 , and with the Allen wrench inserted in bore  278  of the first tilt-latch assembly  104  to prevent its plunger  222  from being retracted, linking member  106  is drawn relatively taut before being locked in place and trimmed. Once linking member  106  is in place and taut, base assembly  108  of actuator assembly  102  may be dropped into cavity  314  so that spool  162  is received in lower cavity portion  318 . As spool  162  enters lower cavity portion  318 , chamfered edges  386  guide linking member  106  into slots  384  of spool  162  respectively. Fasteners  328  may then be driven through mounting posts  186  to secure actuator assembly  102  to top rail  308  and base assembly  108  engaged with linking member  106  to complete assembly. 
     In operation, with inside sash  310  and outer sash  327  in a closed position as depicted in  FIG. 13 , control lever  110  may be positioned in a locked position as depicted in FIGS.  15  and  17 - 19 , wherein control lever  110  is received in keeper  122  or other structure on outer sash  327 , thereby locking inside sash  310  and outer sash  327  together. Sweep cam  118  of control lever  110  is engaged in locking tab  124  of keeper  122  to provide a locked position. In the locked position, spool  162  remains aligned so that linking member  106  is not under tension and latch-bolt portions  248  of latch-bolts  34  project outwardly into grooves  332  in window frame  334 , thereby preventing tilting of inside sash  310 . 
     Window  312  may be unlocked by rotating lever  110  to an unlocked position as depicted in  FIG. 20 . In the unlocked position, sweep cam  118  of control lever  110  does not engage locking tab  124  of keeper  122 . Once again, latch-bolts  34  are not retracted and project outwardly into grooves  332  to prevent tilting of inside sash  310 . As control lever  110  and cam  158  rotate from the locked position to the unlocked position, cam  158  travels between cam followers  219  without causing gear  160  to rotate. 
     Generally, cam  158  is shaped and cam followers  219  are shaped and positioned so that control lever  110  has a rotational range of travel between approximately 100° and 160° degrees from the locked position to the unlocked position. In an example embodiment, control lever  110  has a range of rotation of travel of approximately 135° between the locked and unlocked positions. Between the locked and unlocked positions, biasing member  164  biases cam  158  primarily toward a locked or unlocked position. A neutral position exists in which the biasing member  164  acts upon cam  158  such that cam  158  remains substantially stationary between the locked and unlocked positions. For cam  158  to remain in the neutral position, a line between acute corners  158 A,B is substantially perpendicular to flex regions  150 ,  152  biasing member  164 . Generally, a neutral position exists at the midpoint between the locked and unlocked positions. The neutral position may, however, include any number of degrees of rotation of travel of control lever  110  between the locked and unlocked position. Generally, this neutral position is considered unfavorable and has been minimized by rounding the corners of cam  158  so as to cause cam  158  to slip past flex regions  150 ,  152  of biasing member  164 . Between the locked position and the neutral position, biasing member  164  biases cam  158  toward the locked position. 
     Generally, cam  160  is shaped and cam followers  219  are shaped and positioned so that control lever  110  rotational range of travel between approximately 15° and 75° from the unlocked position to the tilt position. In an example embodiment, control lever  110  rotates approximately 45° between the unlocked and tilt positions. Between the unlocked and neutral positions, biasing member  164  biases cam  158  toward the unlocked position when rotating control lever  110  to the tilt position. 
     With window  312  unlocked, inside sash  310  may be tilted inward by rotating lever  110  to a tilt position as depicted in  FIG. 21 . As control lever  110 , acute corners  158 A,B of cam  158  engages gear sector  388  of spool  162  causing spool  162  to rotate, thereby applying tension to linking member  106 . The tension on connecting member  106  draws plunger  222  of each tilt-latch assembly  104  inwardly toward actuator assembly  102 , sliding plunger  222  within housing  220  against the bias of primary spring  224  and drawing latch-bolt portion  248  within housing  220 . As leading edge  253 A of latch-bolt portion  248  clears plate portion  294  of plunger-latch  226 , latch spring  228  urges plunger-latch  226  in the direction of outer sash  327  so that plate portion  294  partially blocks aperture  266 . Leading edge  253 A of latch-bolt portion  248  engages plate portion  294 , holding plunger  222  retracted within housing  220 . Trigger portion  298  projects slightly from the outer face  336  of top rail  308 . With control lever  110  and tilt latches  34  in tilt position, inside sash  310  may be tilted inwardly to gain access to the outside of the window. In the tilt position, biasing member  164  biases cam  158  toward the unlocked position. 
     Once the window cleaning or other operation is completed and it is desired to return inside sash  310  to its operable position, inside sash  310  may be simply tilted back into position. Trigger portion  298  contacts outer sash  327 , urging plunger-latch  226  against the bias of latch spring  228 . When plunger-latch  226  clears leading edge  253 A of latch-bolt portion  248 , primary spring  224  urges plunger  222  in the direction away from actuator assembly  102 , so that latch-bolt portion  248  extends outwardly through aperture  266  and engages in grooves  332 . 
     In an alternative embodiment of the present invention, top rail  308  is substantially hollow as is typically the case in vinyl window construction. Reinforcing insert  338  fits inside hollow top rail  308  to provide support for the tilt-latch assemblies  104 . Housing  220  of each tilt-latch assembly  104  has spring securing tabs  340  projecting on opposite sides proximate outer end  342 . Each tab  340  is resiliently attached to housing  220  at hinge line  344 . Outer end  346  is normally spaced apart from housing  220 , but is capable of being pressed inwardly into opening  348  in barrel portion  232  Lip  349  extends outwardly around perimeter  349 A of end wall  349 B. Housing  220  further has opposing flats  350 ,  352 . Flat  350  has longitudinal ridge  354  defined thereon. 
     Tilt-latch assembly  104  is received through apertures  356  in top rail  308  and inside reinforcing insert  338 . Insert  338  is preferably made from metal, but may also be made from any other suitably rigid and durable material. Flats  350 ,  352 , mate with inside walls  358 ,  360 , of reinforcing insert  338  respectively to inhibit undesired rotation of tilt-latch assembly  104  about its longitudinal axis. Longitudinal ridge  354  mates with corresponding groove  362  in inside wall  358  so that tilt-latch assembly  104  is coded for proper orientation. As each tilt-latch assembly  104  is advanced into aperture  356 , tab  340  contacts edge  364 , forcing outer end  346  inwardly. Once outer end  346  clears edge  364  and lip  349  contacts outer surface  366  of top rail  308 , outer end  346  springs outwardly to engage inner surface (not depicted) of top rail  308  to retain tilt-latch assembly  104  in place. 
     As depicted in  FIG. 15 , optional keeper  122  generally includes locking tab  124  defining a finished outer surface  124 A and skirt portion  124 B. Skirt portion  124 B defines recess  124 C for receiving outer wall  118 A of sweep cam  118 . Skirt portion  124 B engages circumferential recess  118 B of sweep cam  118  when sweep cam  118  is rotated to the “locked” position. Openings  122 A may be defined in skirt portion  124 B for receiving fasteners (not depicted) to secure keeper  122  to bottom rail  378  of outer sash  327  at a location adjacent actuator assembly  102  when bottom rail  378  is adjacent top rail  308  of inside sash  310 .