Window Locking System

The present invention relates to a locking system for casement windows. In particular, the present invention relates to a locking system to secure a sash of a casement window to a window frame through progressive engagement of multiple locking points.

Multi-point locking system for casement windows have been provided in the past to secure a window sash to a window frame at one or more locking points (e.g. a strike and mating receiver arrangement), typically located at two points (i.e. upper and lower) along the vertical edge of the sash and frame. Such locking systems are adapted to respond to the manipulation of an operator mechanism (typically with a rotatable handle) through which an input force is applied (the operator typically being located at the side of the window frame adjacent to or between the locking points) which actuates a locking mechanism (including a lockbar and a lockbar retainer) to engage the locking points. Such locking systems may engage either all of the locking points at the same time according to a common arrangement, or each locking point sequentially, as shown in U.S. Pat. No. 4,991,886, issued to Nolte et al. and U.S. Pat. No. 5,118,145, issued to Tucker.

When simultaneous engagement of all locking points is attempted, considerable input force may be required to manipulate the handle, particularly if there is any misalignment between the sash and the frame or of the corresponding elements of one or more locking points (e.g. strikes and receivers). In addition, there is a possibility that due to misalignment (or other effects) less than all of the locking points will actually engage, which results in the incomplete "locking" of the window.

As disclosed in the Nolte patent, it has been found that the effects of misalignment may be reduced in an arrangement providing for sequential engagement of the locking points (e.g. strikes and keepers). However, in the sequential locking arrangement of the Nolte patent, which includes a set of keepers with a ramped section and generally planar section, with mating strikes mounted at varied centers (i.e. distances relative to the corresponding mating keeper), the input force required for locking may be discontinuous. Depending upon the alignment of the window or arrangement of the various locking points, greater input force may be necessary for engagement of one locking point than another.

It would be advantageous to provide a progressive multi-point locking system for a casement window offering advantages over both a conventional locking system (i.e. where all of the locking points are simultaneously engaged) and a sequential locking system (i e. where the locking points are engaged in sequence). It would be advantageous to have a progressive locking system that readily provides for smooth and even locking action. It would also be advantageous to have a window locking system adapted for mounting of the operator mechanism (with handle) at the bottom of the frame and mounting of the locking mechanism (with locking points) at the side, including a motion translation device of relatively simple construction coupling the operator mechanism to the locking mechanism. It would further be advantageous to have an arrangement wherein it is readily possible to remove the handle and a bezel of the operator mechanism (which is secured to the frame by fasteners which are accessible from inside whether the window is in the locked or the unlocked position) to allow for repair without damaging the window or the frame. It would further be advantageous to have a lockbar retainer suitable for low-cost manufacturing, such as is formed as a single piece from a plastic material. It would further be advantageous to have a lockbar retainer that is relatively compact in size.

The present invention relates to an apparatus for locking a window having a frame and a sash movable relative to the frame, with a first receiver mounted to the sash and a second receiver mounted to the sash, the first receiver having a retaining profile, a lockbar coupled to the frame and selectively movable between a locked position and an unlocked position, and a first strike mounted to the lockbar and a second strike mounted to the lockbar. The apparatus also includes at least one lockbar retainer coupled to the frame and slidably retaining the lockbar. The apparatus further includes an input device coupled to the lockbar adapted to selectively move the lockbar between a locked position and an unlocked position.

The present invention relates to an apparatus for locking a window having a frame and a sash movable relative to the frame, with a first receiver mounted to the sash and a second receiver mounted to the sash, the first receiver having a retaining profile, a lockbar coupled to the frame and selectively movable between a locked position and an unlocked position, and a first strike mounted to the lockbar and a second strike mounted to the lockbar. The apparatus also includes at least one lockbar retainer coupled to the frame and slidably retaining the lockbar. The apparatus further includes an input device coupled to the lockbar adapted to selectively move the lockbar between a locked position and an unlocked position. Progressive locking of the sash to the frame is developed as the lockbar is moved from the unlocked position to the locked position, the first strike being engaged with and progressively received and retained along the retaining profile of the first receiver, progressive locking continuing as the second receiver engages and retains the second strike.

The present invention further relates to a lockbar retainer for guiding and holding a lockbar of a window locking system. The lockbar, has at least one slot and at least one strike. The lockbar is also coupled to the frame and is selectively movable between a locked position and an unlocked position. The lockbar retainer has a first portion having at least one slot and having side walls to guide the lockbar. The lockbar retainer also includes a second portion interconnecting the first portion and thereby forming a cavity between the two portions. The lockbar moves through the cavity formed by the two portions of the lockbar retainer.

FIG. 1 is a perspective cutaway view of a casement window (with a sash and a frame) showing exposed an exemplary embodiment of a multi-point locking system with an operator mechanism and a locking mechanism incorporating a transmitting device.

FIG. 2 is a front view of the locking system.

FIGS. 3A through 3C are side views of the locking mechanism of the locking system in various stages of engagement.

FIG. 4A is a top plan view of the operator mechanism.

FIGS. 4B and 4C are front views of the operator mechanism.

FIG. 5 is an exploded perspective view of the transmitting device according to an exemplary embodiment.

FIG. 6 is an exploded perspective view of two sections of a transmitting device according to an alternative embodiment.

FIG. 7 is a side elevation view of the transmitting device shown in FIG. 6.

FIG. 8 is a cross sectional view taken along the lines 8--8 in FIG. 7.

FIG. 9 is a cross sectional view taken along the line 9--9 in FIG. 7.

FIG. 10 is a side elevation view of the transmitting device of FIG. 6 installed in the frame with coupling made to the locking mechanism and the operator mechanism.

FIG. 11 is a cross sectional view taken along the line 11--11 in FIG. 10.

FIG. 12 is a cross sectional view taken along line 12--12 in FIG. 10.

FIG. 13 is a cross sectional view taken along line 13--13 in FIG. 10.

FIG. 14 is a cross sectional view taken along line 14--14 in FIG. 10.

FIGS. 15A through 15C are front elevation views of a locking system (with portions broken away) according to an alternative embodiment.

FIG. 16 is a side view of the multi-point casement window locking system shown in FIG. 15C.

FIGS. 17 through 20 are top plane views of alternative forms of locking elements of a locking system according to alternative embodiments.

FIGS. 21 and 22 are elevation views of a locking system similar to FIGS. 15A and 16 but in a reversed orientation (which portions broken away) according to an alternative embodiment.

FIG. 23A is a perspective view of an operator mechanism according to an alternative embodiment (with the frame shown in phantom lines).

FIG. 23B is an exploded perspective view of the operator mechanism of FIG. 23A.

FIG. 24 is a top plan view of the operator mechanism shown in FIG. 23.

FIG. 25 is a cross sectional view taken along the line 26--26 in FIG. 24.

FIG. 26 is a cross sectional view taken along the line 26--26 in FIG. 24.

FIG. 27 is a graph representative of the relationship between closing force and input movement required to engage two locking points on a window in accordance with a sequential locking system known in the art and an exemplary embodiment of a progressive locking system.

FIGS. 28 and 29 are front elevation views of a locking system (with portions broken away) according to an alternative embodiment.

FIG. 30 is a cross sectional view taken along the line 30--30 in FIG. 28

FIG. 31 is a perspective view of the lockbar retainer of FIGS. 28 through 30.

FIG. 32 is a cross sectional view taken along the line 32--32 in FIG. 31.

FIG. 33 is a cross sectional view taken along the line 33--33 in FIG. 31.

FIG. 34 is a perspective view of the lockbar retainer disengaged from the lockbar.

FIG. 35 is a cross sectional view taken along the line 35--35 in FIG. 34.

Referring to FIGS. 1 through 3C, of a multi-point locking system for a casement window according to a preferred embodiment of the present invention is shown. Casement window 100 is of a conventional construction and includes a generally orthogonal window sash 102 (with glass sheet) disposed to fit within a generally orthogonal window frame 104. Sash 102 is mounted to frame 104 according to a conventional arrangement as to enable selective movement (typically pivotal or both pivotal and translational) between a fully opened position an(d a closed position. Sash 102 and frame 104 are provided with a locking system 120 by which sash 102 can selectively be secured to frame 104. Locking system 120 includes a locking mechanism 122 (mounted at the vertical edge of frame 104 and sash 102) and an operator mechanism 110 shown partially contained in a housing (mounted at the bottom edge of frame 104) with an exposed handle 112. Locking mechanism 122 (oriented in a vertical direction) and operator mechanism 110 (oriented in a horizontal direction) are coupled by a force transmitting device 130 (mounted into the corner of frame 104).

Referring to FIG. 2, locking system 120 is shown from the inside of a space defined by casement window 100. Operator mechanism 110 (in a housing 111) is evident at the bottom of frame 104. Also evident is transmitting device 130 which, along with operator mechanism 110, defines an input device 114 configured to actuate locking mechanism 122. (According to alternative embodiments of the present invention the input device may not include an element such as transmitting device 130; the operator mechanism may be mounted to the vertical edge of frame 104.) Locking mechanism 122 includes lockbar 124 which extends vertically through and is slidably retained within two vertically oriented guides shown as tracks 126 mounted to frame 104 (serving as a lockbar retainer as shown in FIG. 1).

According to the exemplary embodiment, locking mechanism 122 is shown to includes two locking points 140 and 142 (e.g. upper and lower points). Each locking point includes a strike 150 or 152 mounted (through an elongated slot 127 in track 126 as shown clearly in FIG. 3A) to lockbar 124 and a mating receiver 160 or 162 affixed to an exposed edge of sash 102 (by two screws 201 or like fasteners). In FIG. 2, both upper and lower locking points 140 and 142 are shown in a fully engaged or locked position, wherein lockbar 124 has been fully extended away from input device 116 to an upward position; sash 102 is thereby secured to frame 104 (and any associated weather-stripping or the like about each is, maintained in an at least partially compressed state) as to close and lock the window. Strikes 150 and 152 have travelled to the upper ends of elongated slot 127 in each respective track 126. When lockbar 124 is retracted toward input device and to a downward position, both upper and lower locking points 140 and 142 are disengaged and sash 102 is released from frame 104 as to permit pivotal movement and opening of the window. Strikes 150 and 152 have travelled to the lower ends of elongated slot 127 in each respective track 126.

Each of strikes 150 and 152 includes a cylindrical tube-shaped section 153 having an axial bore. Cylindrical post section 151 of each of strikes 150 and 152 is mounted to lockbar 124 by a rivet which extends through the bore and serves as a rigidifying post. (According to a particularly preferred embodiment, cylindrical section 151 is made of a plastic material and is free to rotate about metal rivet.) According to en exemplary embodiment, shown in FIGS. 1 through 3C, lockbar 124 is provided with a pair of strikes 150 and 152. According to alternative embodiments, such as for larger windows, more locking points, e.g. strikes and mating receivers of a similar configuration, could be employed. Strikes 150 and 152 are mounted on (e.g. affixed to) lockbar 124 at a prescribed center spacing (i.e. distance) so as to suitably engage a pair of receivers 160 and 162 secured to the perimeter of sash 102 as locking mechanism 122 is, actuated.

Each of receivers 160 ant 162 includes a base section 163 by which mounting is effected and a retaining section 165 extending therefrom to provide an arcuate retaining profile 166 or 168 along which each of strikes 150 and 152 (i.e. at cylindrical section 151) will travel during engagement and disengagement. (According to a particularly preferred embodiment, receivers 160 and 162 are made of a metal or durable plastic material.) As shown in FIGS. 3A through 3C, lower receiver 162 is provided with a retaining portion 168 having an arcuate profile generally of a first curved radius; upper receiver 160 is provided with a retaining portion 166 having an arcuate profile of a curved radius. Retaining portion 166 of upper receiver 160 is shorter in length and of a smaller radius than retaining portion 168 of lower receiver 162.

Lockbar 124 is coupled to an output link 118 of input device 116 (typically by a fastener like screw 203) and is thereby linearly actuated between a fully-locked and a fully-unlocked position by appropriate manipulation of operator mechanism 110. Operator mechanism 110 is manipulable through handle 112 (e.g. a lever) by which a rotary input movement is imparted to an internal linkage and translated into a suitable linear output movement.

Lockbar 124 is slidably retained within tracks 126. Each track 126 is of a rectangular shape (and cross-section) and is provided with elongated slot 127 within which strike 150 or 152 (extending therethrough) will travel as lockbar 124 is actuated. Each track 126 is of a rectangular cross-section slightly larger in its inner perimeter than a rectangular cross-section of lockbar 124 which has a slightly smaller outer perimeter, so as to allow relatively free slidable movement of the lockbar 124 with respect to and within track 126. (According to a preferred embodiment, the lockbar is made of a suitably strong and rigid material such as metal and each track is made of a durable metal or plastic.) Each track is mounted to frame 104 by screws 205.

FIGS. 3A through 3C show locking system 120 with locking points 140 and 142 in three stages of engagement, namely fully engaged (i.e. "locked"), partially engaged, and completely disengaged (i.e. "unlocked"). In FIG. 3A, sash 102 is "locked" (i.e. secured) to frame 104 and the engagement of upper and lower locking points 140 and 142 is evident, with upper strike 150 retained along retaining profile 166 of upper receiver 160 and lower receiver 162. In FIG. 3B, lower locking point 142 is engaged but upper lower locking point 150 is disengaged (as would be the case either when locking or unlocking of the window is incipient) and sash 102 is only partially secured to frame 104. As is evident in FIG. 3B, once lower strike 152 has been retained at this point along retaining profile 168 of lower receiver 162, upper strike 150 has been pulled toward upper receiver 160 and as locking action continues, lower strike 152 is guided along arcuate retaining profile 168 of lower receiver 162. In FIG. 3C, both upper and lower locking points 140 and 142 are completely disengaged (and sash 102 is shown pivoted away from frame 104). As is seen in comparison of FIGS. 3A through 3C, the relative distances between the mounting positions of strikes 150 and 152 (on lockbar 124) and the mounting positions of corresponding receivers 160 and 162, as well as the shape of retaining profiles 166 and 168, will tend to facilitate a smooth and progressive locking effect.

As is evident, with sash 102 drawn to the closed position with respect to frame 104 (as shown in FIG. 3B), progressive locking action can be effected. At handle 112 an input force is applied to provide an input movement which is transmitted from operator mechanism 110 to locking mechanism 120. Handle 112 is rotated in the counter-clockwise direction (from the "unlocked" position to the "locked" position), driving output link 118 of input device 116 to urge lockbar 124 and lower strike 152 upward to the point where it first engages an exposed surface presented by retaining profile 168 of lower receiver 162 (near its free lower end). As handle 112 is rotated further in the counter-clockwise direction, lower strike 152 travels along retaining profile 168 of lower receiver 162, pulling and drawing sash 102 into a more tightly closed position with respect to frame 104; pulling will continue to a point where upper strike 150 can readily be captured by retaining profile 166 of upper receiver 160 notwithstanding any misalignment that may exist in or between sash 102, frame 104 or any of the various elements of locking system 120. As handle 112 is rotated still further, and lower strike 152 travels further along arcuate retaining portion 168, upper strike 150 will begin to engage an exposed surface presented by retaining profile 166 of upper receiver 160 (near its free lower end). Due to the longer length of retaining profile 168 (of lower receiver 162) as compared to retaining profile 166 (of upper receiver 160), the engagement of lower strike 152 with lower receiver 162 progressively pulls sash 102 into a more tightly closed position, which serves to ensure that upper strike 150 will be in a position for capture by retaining profile 166 of upper receiver 160. As handle 112 is rotated still further, upper strike 150 begins to travel along arcuate retaining profile 166 of upper receiver 160 while lower strike 152 continues to travel along retaining profile 168 of lower receiver 162. By the time handle 112 has been moved to a fully counter-clockwise position, the lower strike 152 and upper strike 150 will each be fully received under retaining profiles 168 and 166 of corresponding lower receiver 152 and upper receiver 150.

As is evident, with the locking mechanism operating in this manner, an input force applied to handle 112 to lock the casement window is smoothly and progressively employed to bring sash 102 into the locked position by first engaging lower strike 152 along the gentler slope of retaining portion 168 of lower receiver 162, and only after sash 102 has begun to move to its fully-closed position is upper strike 150 taken into engagement with retaining portion 166 of upper receiver 150. Unlocking releases locking points 140 and 142 in the reverse progression. As is also readily apparent in view of the disclosure of the present invention, in alternative embodiments, the shapes of either the strikes or the receivers can be adjusted in various combinations of shapes, sizes and mounting center distances to obtain a desired progressive locking effect. (In alternative embodiments, the respective positions of the strikes and receivers with respect to the lockbar and window frame may be reversed.)

Referring to FIGS. 4A through 4C, operator mechanism 110 is shown in greater detail. The internal arrangement of operator mechanism 110, no longer shown as contained within a housing 111, is shown in FIG. 4A. Handle 112 extends outwardly through a removable bezel 170 (e.g. a "snap-fit" cover plate) affixed to a front mounting plate 172 affixed to housing 111 by fasteners (shown as screws 207). Handle 112 is pivotally mounted (as shown at point 250) to housing 111 (or a mounting plate) which is secured to frame 104. Handle 112 is pivotally attached (as shown at point 252) to a coupler link 117 which in turn is pivotally attached (as shown at pivot point 254) to an output link 118 that is coupled (by one or more screws) transmitting device 130 (shown to include a tape 134 slidably retained within a guide 132). According to a particularly preferred embodiment, the pivot points are rivets or posts (with spacers as needed).

With handle 112 in the "locked" position (shown by the full lines in FIG. 1), coupler link 117 is moved to the left, in which position lockbar 124 (through output link 118 and transmitting device 130) is advanced to a "locked" position, where the locking points 140 and 142 are engaged. Conversely, when handle 112 is rotated to the right, lockbar 124 is returned to the "unlocked" position (shown by the dashed lines in FIG. 1), where the elements of locking points 140 and 142 are no longer engaged. (According to the exemplary embodiment shown in FIG. 1, a tape 134 of transmitting device 130 serves as output link 118 of input device 116, in alternative embodiments, other intermediate links may be included to provide the progressive locking function; in further alternative embodiments without the transmitting device, the coupler link may serve directly as the output link of the input device.)

As shown in FIGS. 1 through 4, locking system 120 may be provided with transmitting device 130 such that horizontally-disposed operator mechanism 110 (located at the base or bottom of frame 104) can be used to actuate vertically-disposed locking mechanism 122 (located on the side of frame 104 and sash 102). Transmitting device 130 of a type that can be used to effectuate the "around the corner" coupling of operator mechanism 110 to locking mechanism 122, according to a conventional exemplary embodiment, is shown in FIG. 5. Transmitting device 130 includes a one-piece guide 132 (adapted for mounting to frame 104) and a longitudinally stiff and laterally flexible tape 134 disposed in a slot 136 in guide 132 to provide a suitably rigid coupling between operating mechanism 110 and locking mechanism 122.

As is evident from FIGS. 1 through 5, an input force applied to operator mechanism 110 by movement of handle 112 is transmitted through output link 118 and to tape 134. As shown in FIG. 5, coupling of output link 118 to tape 134 includes a rivet 256 which passes through corresponding apertures in output link 118, a retaining spacer 158 and tape 134. The manner in which tape 134 is connected to locking mechanism 110 is similar with a rivet or screw (shown by reference numeral 160) which passes through lockbar 124, a retaining spacer 262 and tape 134.

Referring to FIGS. 6 through 14, a guide 232 according to a particularly preferred embodiment is shown. Guide 232 is formed of two substantially identical sections 231 and 233. The cross-section of each of sections 231 and 233 is generally J-shaped, having a longer leg 234, a base 235 and a shorter leg 236. Sections 231 and 233 are formed with a curved portion and two legs extending from curved portion at right angles to each other. Each of sections 231 and 233 is provided with a pair of mounting tabs extending from longer legs 234. Each of mounting tabs 237a and 237b is formed with a thickness which is approximately one-half of that of longer leg 234. Mounting tab 237a is formed closer to shorter leg 236, while mounting tab 237b is formed with one side flush with the outer surface of longer leg 234. Curved portion of each of sections 231 and 233 is provided with a hole 238 and a projecting pin 239. When assembled to form guide 232, sections 231 and 233 are mated with each other, as tabs 237a and 237b overlay each other. The overlayment of tabs 237a and 237b is best shown in FIG. 8; the mating of pins 239 and holes 238 are best shown in FIG. 9. Pins 239 are received in holes 238 in a "snap fit" arrangement to secure sections 231 and 233 to each other. Each of tabs 237a and 237b is provided with an aperture 240 for receiving a fastener for securing guide 232 to frame 104. Tabs 237a and 237b are provided with counter-sinks 241 such that the head of a fastener suitably passing through aperture 240 will not protrude or project into a slot 236 (which is adapted to receive a slidable tape) formed between two sections 231 and 232 as shown in FIG. 8. FIG. 7 shows guide 232 assembled in a corner of frame 104 (which is shown broken away). A tape 134 is shown projecting from the upper end of guide 232 (and is further shown in a broken away bottom portion of guide 232). (According to a particularly preferred embodiment, guide 232 is made of a durable plastic material such as "DELRIN".)

Referring to FIGS. 10 through 14, it is shown that guide 232 is secured to a rigidifying metal strip 242 by a fastener such as a rivet 209 shown in FIG. 13, which secures sections 231 and 233 of guide 232 to each other and to strip 242. As shown in FIG. 11, coupler link 117 is retained to strip 242 by a rivet-like fastening member 211 which passes through a hole in strip 242, a slot in link 117, and a hole in a U-shaped clamp 243; the legs of clamp 243 are received in slots formed in strip 242. Lockbar 124 is coupled to tape 134 by a rivet 213 which extends through a hole in spacer 215, an elongated slot in output link 118, a hole in a spacer 217, and a hole in a U-shaped clamp 244; the legs of clamp 244 are received in slots in strip 242.

Referring to FIGS. 15A through 16, and FIGS. 21 through 22 (showing a reversed mounting orientation), an alternative embodiment of this invention is shown (in which similar components of the multi-point lock arrangement are identified with the same reference numerals). Because this alternative embodiment is primarily directed to a variation in strike and receiver construction, the input device (e.g. operator mechanism) is not shown. In this embodiment, receivers 360 and 362 are of a more compact form, having mounting section 364 provided with six holes 365 oriented in a staggered pattern so as to provide for a plurality of variations in mounting positions (although in alternative embodiments mounting may be effected with fewer or more holes or by other known mounting arrangements, which may depend on the configuration of the receiver or other elements). Lower receiver 362 has an arcuate retaining profile 368. Upper receiver 360 has an arcuate retaining profile 366 of a smaller radius than arcuate retaining profile 368 of lower receiver 362. As shown in comparison of FIGS. 15A through 15C (and also FIGS. 21 and 22, in a reversed orientation for a opposite-side window mounting), it can be readily observed that lower strike 152 will engage arcuate retaining profile 368 of lower receiver 362 prior to any engagement by upper strike 150 with arcuate retaining profile 366 of upper receiver 360. After lower strike 152 first travels along retaining profile 368, upper strike 150 will then engage and travel along retaining profile 366, to provide a continuous and progressive locking of the window sash to the window frame. (Mating full-strikes 150 and 152 as shown in this exemplary embodiment are provided with a rim 351 that may ride over the outer surface of a lip 361 of each retaining profile 366 and 368.)

According to the alternative embodiment shown in FIGS. 15 through 16, each track 126 of locking mechanism 122 includes a detent arrangement that is configured to releasably retain locking mechanism 122 in either a locked or unlocked position. (As shown, track 126 is secured to the window frame by suitable fasteners such as screws received in holes 219, and are provided with elongated slot 127 respectively, through which strikes 150 and 152, coupled to lockbar 124 by posts or rivets, extend.) A pair of inwardly extending and opposed projections shown as detents 129 are provided near each end of slot 127. Detents 129, which extend into slot 127, are spaced apart (i.e. across slot 127) as to provided a slight interference and frictional resistance as strikes 150 and 152 (which are of a lesser cross-section dimension than slot 127, but greater cross-section dimension than the distance across detents 129) pass between detents 129. As handle 112 is moved from the locked position to the unlocked position, the resistance presented by detests 129 will tend to provide an indication (e.g. a snap or click) to a person operating handle 112 that the locking points have reached either the fully-engaged or fully-disengaged position. Detents 129 also serve to hold certain elements of locking mechanism 110 (e.g. lockbar 124 and track 126) together (e.g. in the fully closed position) during the shipment and field installation of the locking system.

Referring to FIGS. 17 and 18, an alternative embodiment of first and second locking elements (e.g. receivers) configured to provide progressive locking when installed in the locking system is shown. (Strikes 150 and 152 are shown in phantom lines.) First and second locking elements 340 and 342 respectively are of a compact form and have a mounting section 341 and a retaining section 343. Each mounting section 341 is provided with two sets of three holes for mounting on a window sash by a known fastener arrangement (e.g. screws) in a variety of orientations. Each retaining section 343 has a symmetrical retaining profile 345 with upper and lower retaining surfaces 345a and 345b. Only ore of these retaining surfaces will be used to provide the locking action for the window sash. However, because each locking element is provided with two retaining surfaces, it may be mounted with mounting section 341 extending toward either the right or the left side of the sash. As a result, arcuate retaining section 343 of each of first and second locking elements 340 and 342 have a retaining profile 345 with two retaining surfaces 345a and 345b that will function according to the mounting orientation. The retaining section may be provided with an intermediate recess (not shown) to retain a strike slightly when it has travelled to a substantially central point along the retaining profile.

Referring to FIGS. 19 and 20, an alternative embodiment of first and second locking elements (e.g. upper and lower receivers) configured to profile provide progressive locking is shown. (Strikes 150 and 152 are shown in phantom lines.) First and second locking elements 320 and 322, respectively, are formed as brackets having substantially parallel mounting and retaining sections 324 and 326 connected by an offsetting section 325. In order to provide for greater adjustment and mounting flexibility, mounting section 324 is provided with two sets of five holes so as to provide for a plurality of alternative mounting positions on a window sash. Retaining profiles 330 and 332 are provided with arcuate-shaped engaging edges 334 and 336 that are configured to develop a particular progressive locking effect when installed in the progressive locking mechanism.

It has been observed that in a multi-point locking system when multiple strikes are simultaneously engaged upon multiple receivers, misalignment of the receivers and strikes may increase the input force necessary to affect engagement of all receivers and strikes (if successful engagement is even possible). In sequential locking systems where first one strike and its mating receiver is engaged, and then other strikes and other mating receivers are engaged sequentially, the required operating force may fluctuate (i.e. increase and decrease) significantly as each set of strikes and mating receivers are engaged, one after another. The progressive engagement of a multi-point locking system may provide for a general reduction in (or smoothing) of the input force required to effect locking.

FIG. 27 is a graphical relationship of the input rotation (e.g. handle position) and approximate locking force required to sequentially engage two locking points in accordance with a prior are arrangement (shown in a representative fashion shown by a dashed line S) and the approximate locking force required to progressively engage two locking points by employing a locking system in accordance with an exemplary embodiment of the present invention (shown in a representative fashion in a solid line P). The closing force is represented by the vertical axis, and the input rotation on the horizontal axis. It will be noted that there are two relatively significant peaks in the closing force of the sequential locking arrangement (see line S). It should be noted that not only can the peak force be reduced somewhat with a progressive locking arrangement, but also that only one significant force peak is encountered (see line P), occurring as the second locking point is engaged. As illustrated, with a progressive locking arrangement, an overall reduction in locking force may be achieved and significant repetitive increases and decreases in the locking force may be reduced. (The unlocking forces would follow along the same basic curve as shown for closing except in the opposite direction.) This progressive locking arrangement provides for a locking system that may be more appropriate for use with an automated control (or a motor drive) or integrated operation system for both opening (or closing) the window and unlocking (or locking) the window.

Referring now to FIGS. 23A through 26, wherein operator mechanism 110a is shown in accordance with an alternative embodiment. (The locking system shown in FIGS. 4A through 4C is similar in most aspects to that shown in the previously described embodiments, except that operator mechanism 110a, and particularly the manner in which it is mounted within frame 104a (of a different window type, e.g. extruded) has been modified; similarly components in FIGS. 23A through 26 are identified by the same numerals used with respect to previously described embodiments.) Referring to FIG. 23B, a multi-piece handle 112a is received through a bezel 170a and a faceplate 172a into a housing 111a mounted at or within frame 104a. Referring to FIGS. 23A and 23B, it will be seen that by removing bezel 170a (which is configured for a snap fit into housing 111a by a set of projections 171a), access may be made to fasteners shown as screw 218 which secures faceplate 172a of operator, mechanism 110a to housing 111a.

Handle 112a has a removable level section 112b which is insertable into a pivot section 112c and held by a clip 112d. Bezel 170a conceals faceplate 172a (which is fastened to housing 111a by two screws 218) when snapped into place, so that only bezel 170a and level section 112b of handle 112a are ordinarily visible through frame 104a. Pivot section 112c of handle 112a is pivotally coupled through a mounting hole 111b in housing to a coupler link 117a by a coupler element 117b; coupler link 117a is then pivotally coupled to an output link 118a. (Each pivotal coupling is shown to employ a pivot pin 200 with a mating retaining element 202 and a washer or like spacer 204.) As shown in FIGS. 24 to 26, this arrangement of operator mechanism 110a is substantially contained in a mounting region of frame 104.

This mounting arrangement quite advantageously provides for free access to operator mechanism 110a from the interior space or area defined by the casement window installation, regardless of whether the window is in an open or closed state (advantageously compared to prior arrangements for mounting the operating mechanism, which generally can only be accessed when the window is open). Should locking system 120 somehow fail to operate with the window locked in the closed position, access to operator mechanism 110a may be gained from the interior space by removing bezel 172a and screw 218. Moreover, the removable and thus interchangeable bezel and handle arrangement (particularly when color-coordinated) facilitates a system wherein a variety of external or cosmetic effects may be provided, depending on customer preferences (e.g. to match color schemes), without the need for any internal changes to the operator mechanism.

While the locking system has generally been described with reference to embodiments having two locking points (e.g. two strikes and two receivers), a greater number of locking points could tie employed without departing from the teachings of this invention. When more than two locking points (e.g. strikes and mating receivers) are employed, according to alternative embodiments, the retaining profiles of the receivers may be conformed to provide for progressive engagement with the associated strikes, typically beginning with the locking point nearest to the operator mechanism and ending with the locking point furthest from the operator mechanism. According to any preferred embodiment, to effect the progressive engagement of the mating strikes and receivers, the receiver closest to the input device (which is engaged first) will have a longer and more gently curved radius at its retaining portion, and subsequently any other receivers (subsequently engaged) will have successively a shorter and more sharply curved retaining portion. In alternative embodiments, subsequent (e.g. middle and upper etc.) receivers may be of identical shape; in such an embodiment, progressive locking may be effected at the first-engaged locking point followed by the simultaneous engagement at all other locking points. According to alternative embodiments, the progressive locking effect could be adjusted by varying the relative center mounting distances between the locking elements (e.g. strikes) on the frame and the mating locking elements (e.g. receivers) on the sash in any operable arrangement that allows complete engagement of all locking elements in the fully-locked position. In other embodiments, all locking elements can be configured to resemble receivers which are oriented to progressively engage one another along their respective retaining profiles.

Referring to FIGS. 28 through 35, an alternative embodiment of the present invention is shown. Because this alternative embodiment is primarily directed to a variation in the construction of one element associated with the locking mechanism, i.e. the lockbar retainer and lockbar/track construction, the input device (e.g. operator mechanism ) is not shown. The locking elements (e.g. strikes and receivers) may function similarly to the strike and receiver depicted in FIGS. 15A through 16. However, according to alternative embodiments other types of locking elements, such as conventional arrangements of strikes and receivers (not shown) could be used.

According to the alternative embodiment shown in FIGS. 28 through 35, the locking mechanism employs a lockbar retainer 422 having a top portion 424 (e.g. cover) and a bottom portion 426 (e.g. base). Preferably lockbar retainer 422 is formed from a plastic or polymeric (e.g. molded) material, although other suitable materials may be used according to alternative embodiments. As shown, lockbar retainer 422 may be molded so that cover 424 and base 426 form an integral unit (see FIGS. 34 and 35), connected by a hinge 428 (shown as an integral strip of material) with joints 429a and 429b. Joints 429a and 429b are shown as scored regions of plastic strip 428 of sufficient flexibility and strength to allow bending or flexing (without breaking). Hinge 428 thereby allows pivotal movement between cover 424 and bottom base 426 between an "open" position (see FIG. 34) and a "closed" position (see FIG. 32).

According to alternative embodiments, the lockbar retainer may include separate cover and base (i.e. top portion and a bottom portion) with or without a hinge (for example, with the top and bottom portions and being held together by a plurality of clips engaged in a correspondingly positioned plurality of clip recesses or other fastening mechanisms).

When the lockbar retainer is fully assembled (i.e., closed with cover 424 and base 426 clasped together for use), flexible locking members (e.g. clips) 430 of cover 424 engage corresponding clip recesses 432 of base 426. When assembled, a lockbar-retaining region 434 is created between cover 424 and base 426. Further, sidewalls 435 formed in cover 424 define a track through which a lockbar 450 is guided within lockbar-retaining region 434.

Cover 424 includes a slot 436 within which a strike 438 extending from lockbar will travel as the locking elements are fully-engaged or fully-disengaged. A pair of inwardly extending and opposed projections shown as detents 437 are provided near each end of slot 436. Detents 437, which extend into slot 436, are spaced apart (i.e. across slot 436) as to provide a slight interference and frictional resistance as strike 138 (which is of a lesser cross-section dimension than slot 436, but greater cross-section dimension than the distance across detents 437) passes between detents 437. As handle 112 is moved from the locked position to the unlocked position, the resistance presented by detents 437 will tend to provide an indication (e.g. a "snap" or "click") to a person operating handle 112 that the locking points have reached either the fully-engaged or fully-disengaged position. (Audible or tactile indications may be provided, according to any preferred embodiment.) Detents 437 also serve to hold certain elements of locking mechanism 110 together (e.g. in the fully closed position) during the shipment and field installation of the locking system. The detents may, according to an alternative embodiment, be separate or detachable from the lock bar retainer (as an installable member, e.g. a clip or the like).

Cover 424 also includes amounting apertures 440 located approximately adjacent each end of slot 436. As shown, apertures 440 include a recessed (i.e. countersunk) region 442 and a substantially cylindrical (i.e. tubular) casing 444 (which is received within a corresponding recess inside of base 426). According to a preferred embodiment, lockbar retainer 422 is mounted to window frame 104 by fasteners shown as wood screws 446 having heads 447 that fit into recessed regions 442. According to alternative embodiments, other fasteners (such as bolts or rivets or dowels or adhesives, etc.) can be employed to mount the lockbar retainer to the window frame. As shown, casing 444 also serves as a guide for the lockbar. Casing 444 protrudes into lockbar-retaining region 434 (as shown in FIGS. 32 and 33), but lockbar 450 has a corresponding slot 451 within which casing 444 fits to allow lockbar 450 to move within its defined path of travel within lockbar retainer 422 (as shown in FIGS. 28 and 29). This allows the overall dimension (or "footprint") to be reduced in scope. That is, the mounting area of the lockbar retainer to the frame need not be located outside of lockbar-retaining region. (Compare the embodiment shown in FIG. 15A.) As shown in FIGS. 28 and 29 casings 444 fit within slot 452 and therefore may guide but do not interfere with the travel of lockbar 450. (According to a preferred embodiment, the base and the cover of the lockbar-retainer can be separated to readily allow removal of or access to the lockbar.)

Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of the invention as defined in the following claims. In the claims, each means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures.

Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the preferred embodiments without departing from the spirit of the invention as expressed in the appended claims.