Abstract:
A pair of sweep locks and a corresponding pair of tilt latches are combined and mounted together on an upper rail of a lower sash. The tilt latches and sweep locks are then interactively engaged so that locking the sweep locks latches the tilt latches, and unlocking the sweep locks leaves the tilt latches latched. Unlocked sweep locks allow manual unlatching of tilt latches, and relocking of sweep locks automatically relatches tilt latches.

Description:
TECHNICAL FIELD 
     Sweep locks and tilt latches for window sash that open and close vertically and tilt from a vertical plane 
     BACKGROUND 
     “Sweep lock” is the common name of a cam lock mounted on an upper rail of a lower sash to lock the lower sash to a fixed or movable upper sash in a window. Sweep locks can be used in pairs spaced toward the sides of window sash to interlock the check rails of a pair of closed sash. When locked, sweep locks prevent either sash from moving toward an open position and also strengthen the wind resistance of the closed sash. 
     “Tilt latch” is the common name of a latch that keeps a tiltable sash in an upright position for traveling vertically between open and closed positions within a window jamb. Ordinarily, a pair of tilt latches are arranged at stile edges of a lower sash to latch into vertical slots in a window jamb where the tilt latches prevent a lower sash from tilting until the tilt latches are manually unlocked. 
     Since sweep locks and tilt latches are both mounted on an upper rail of a lower sash, there have been several suggestions in the patent literature that these devices be combined. See for example U.S. Pat. Nos. 1,120,186; 5,090,750; 5,244,238; 5,398,447; and 5,791,700. All these suggestions suffer from disadvantages such as expense, inconvenience, and cumbersome actuation. Some of them also cause simultaneous actuation of sweep locks and tilt latches in undesirable ways. In contrast to these drawbacks, the present invention aims at a low cost, convenient, and functionally desirable interaction of sweep locks and tilt latches. 
     SUMMARY OF THE INVENTION 
     The invention achieves this improvement by mounting a corresponding pair of sweep locks and tilt latches adjacent each other so that each sweep lock and each tilt latch are manually movable. The sweep locks are arranged to block unlatching movement of the tilt latches, though, whenever the sweep locks are locked. Also, locking the sweep locks moves unlatched tilt latches into latched positions. The only time tilt latches can be unlatched is when corresponding sweep locks are unlocked. 
     This arrangement assures that tilt latches are latched whenever sweep locks are locked so that the window enjoys maximum possible strength whenever sweep locks are locked. It also requires that the sweep locks be unlocked before tilt latches can be unlatched so that no one attempts to tilt a sash that is held in place with a sweep lock. Since sweep locks are used for locking windows for security and wind-resistance purposes, such an arrangement assures that tilt latches are also latched for the same purposes, whenever the sweep locks are locked. The arrangement also prevents accidental unlatching of tilt latches whenever sweep locks are locked. In normal practice, sweep locks are used more frequently than tilt latches, which are unlatched for tilting a sash inward for washing or repair. The more frequently used sweep locks then ensure that tilt latches remain latched until tilting of a sash is desired, and sweep locks are also unlocked for this purpose. 
    
    
     DRAWINGS 
     FIG. 1 is a fragmentary schematic view of a pair of sweep locks and tilt latches arranged according to the invention to lock a sash within a window. 
     FIGS. 2-4 are isometric top and front side views of a preferred embodiment of sweep lock and tilt latch combination shown in FIG. 2 with the sweep lock locked and the tilt latch latched, in FIG. 3 with the sweep lock unlocked and the tilt latch latched, and in FIG. 4 with the sweep lock unlocked and the tilt latch unlatched. 
     FIGS. 5-7 show an isometric bottom and front side view of the preferred embodiment of sweep lock and tilt latch combination of FIGS. 2-4 with FIG. 5 corresponding to the positions of FIG. 2, FIG. 6 corresponding to the positions of FIG. 3, and FIG. 7 corresponding to the positions of FIG.  4 . 
     FIG. 8 is an isometric exploded view of the preferred embodiment of FIGS. 2-7. 
     FIGS. 9-11 are isometric top and front side views of another preferred embodiment of sweep lock and tilt latch combination shown in FIG. 9 with the sweep lock locked and the tilt latch latched, In FIG. 10 with the sweep lock unlocked and the tilt latch latched, and in FIG. 11 with the sweep lock unlocked and the tilt latch unlatched. 
     FIGS. 12-14 correspond respectively with FIGS. 9-11 and show the embodiment of FIGS. 9-11 with the tilt latch housing removed to illustrate the interaction of the sweep lock and the tilt latch, with FIG. 12 showing the positions of FIG. 9, FIG. 13 showing the positions of FIG. 10, and FIG. 14 showing the positions of FIG.  11 . 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows preferred positioning of the inventive combination of sweep lock and tilt latch arranged in window  10 . A pair of combined sweep locks  30  and tilt latches  50  are arranged on an upper or check rail  11  of lower sash  12 . Combined sweep locks and tilt latches  20  are arranged toward stile edges  13  of sash  12  so that sweep locks  30  can interlock with a lower or check rail  16  of upper sash  14  aligned with lower sash check rail  11 , and tilt latches  50  can latch into vertical grooves in window jambs  15  to prevent lower sash  12  from tilting unless tilt latches are unlatched. Throughout this application, window jambs  15  are intended to include jamb liners such as used in wooden windows, as well as polyvinyl chloride (PVC) window jambs. Both jambs and jamb liners have vertical grooves or slots that tilt latches  50  can latch into, to hold a sash upright. 
     FIGS. 2-8 illustrate specifics of a preferred embodiment of sweep lock and tilt latch combination  20 . In this embodiment, each combination includes a cam-type sweep lock  30  and a sliding type of tilt latch  50  configured to interact with each other in the different positions shown in the drawings. A housing  51  of tilt latch  50  has an overlap region  52  that overlies sweep lock cam  30  and provides a pivotal mount for sweep lock  30 . The overlap region  52  of housing  51  includes a mounting screw bushing  53  that extends through a pivot axis opening  33  in sweep lock  30 . Bushing  53  not only affords a pivot mount for sweep lock  30 , but also receives a mounting screw  23  that secures both sweep lock  30  and overlap region  52  of housing  51  securely in place on upper rail  11  of lower sash  12 . 
     Sweep lock  30  includes a cam lock  31  that interlocks with a receiver  32  mounted on lower rail  16  of upper sash  14 . Receiver  32  is preferably molded with screw-receiving openings  34  so that it can be conveniently secured to upper sash check rail  16 . 
     Tilt latch housing  51  extends toward window jamb  15  from sweep lock  30 , and preferably includes a bushing  54  that receives a screw securing housing  51  to check rail  11 . Tilt latch  50  formed as a laterally movable slide is arranged within housing  51  to move into latched positions shown in FIGS. 2,  3 ,  5 , and  6  and in an unlatched position shown in FIGS. 4 and 7. Latch end  55  of tilt latch slide  50  extends from housing  51  into latching engagement with a window jamb  15  in the latched position and retracts from a window jamb  15  in the unlatched position. A manually grippable projection  59  operates tilt latch  50  to slide back and forth within housing  51 . Bar  59  moves laterally within an opening  56  in housing  51 , and tilt latch slide  50  has a generally oval opening  57  that can slide past screw bushing  53  to accommodate lateral movement of latched slide  50 . Oval opening  57  preferably has a central detent  58  formed as a narrowed region of oval  57 , to detent latch slide  50  against bushing  53  in either a latched or an unlatched position. 
     Tilt latches are also made with springs biasing them lightly toward latched positions and with latch ends that are cammed like door latches. Such latches can be manually retracted against the spring pressure to tilt a sash, and such latches cam over a window jamb and snap into jamb grooves as a sash is moved from a tilted to an upright position. Such an arrangement is common in PVC windows, and such spring-biased tilt latches can be made to cooperate with sweep locks according to the invention. 
     A cam lock region  35  is disposed to block unlatching movement of tilt latch slide  50  whenever sweep lock  30  is locked. An adjacent region  36  of sweep lock  30  is disposed to allow sliding movement of tilt latch  50  whenever sweep lock  30  is unlocked. An end  48  of tilt latch  50  engages sweep lock surfaces  35  or  36 , depending on the locked or unlocked condition of sweep lock  30  and the latched or unlatched condition of tilt latch  50 . 
     Sweep lock and tilt latch combination  20  operates as follows. When sweep lock  30  is unlocked and tilt latch  50  is unlatched, as shown in FIGS. 4 and 7, lower sash  12  is unlocked from upper sash  14  and is free to tilt out of the plane of window  10 . This condition is useful for washing or repairing sash  12 . If tilt latches are spring biased into latched positions, they are latched whenever lower sash  12  is untilted; and the tilt latches have to be moved manually to unlatched positions to tilt an unlocked lower sash  12 . 
     When sweep lock  30  is locked, as shown in FIGS. 2 and 5, tilt latch  50  is latched and blocked from unlatching. As sweep lock  30  moves from an unlocked to a locked position, its cam surface  35  engages tilt latch end surface  48  so that tilt latch  50  slides into a latched position as sweep lock  30  rotates into a locked position. This feature is unnecessary for tilt latches that are spring biased into latched positions and automatically latch whenever lower sash  12  is untilted. Otherwise, locking sweep locks  30  not only interlock sash  12  with sash  14  but also latch tilt latch slides  50  into window jambs  15  for maximum window strength and wind resistance. Neither sash can move up or down or tilt, and window  10  has maximum wind resistance. 
     If lower sash  12  is to be raised or upper sash  14  is to be lowered, sweep locks  30  are unlocked to the position shown in FIGS. 3 and 6. This moves sweep lock surfaces  35  out of the path of tilt latches  50  and disposes sweep lock surfaces  36  to confront ends  48  of tilt latches  50  across gaps, as best shown in FIG.  6 . In such condition, lower sash  12  can be moved up and down for opening and closing window  10 ; and upper sash  14 , if also movable, can be moved down and up. Tilt latches  50  remains latched, however, and held in latched positions by detents  58 , or by springs, so that lower sash  12  cannot be tilted. 
     If tilting of lower sash  12  is desired, it is necessary not only to unlock sweep locks  30  to the unlocked position shown in FIGS. 3 and 6, but also to manually move tilt latch slides  50  to the unlatched position shown in FIGS. 4 and 7. Lower sash  12  can then be raised within window  10  and tilted open for washing or repair. 
     The operation described above has the advantage of leaving tilt latch slides  50  latched unless they are deliberately manually unlatched. Unlocking sweep locks  30  to open a window does not unlatch tilt latches  50 , which is desirable in normal operation. Also, if tilt latches  50  are unlatched, they automatically become relatched whenever sweep locks  30  are locked. This ensures that someone locking window  10  with sweep locks  30  will get the additional strength and wind resistance afforded by latching tilt latches  50 . 
     A requirement for unlatching tilt latches  50  is that sweep locks  30  must first be unlocked. This is not an inconvenience, however, because tilting sash  12  requires that sweep locks  30  be unlocked. The arrangement thus allows deliberate unlatching of tilt latches  50  whenever desired and ensures that tilt latches  50  are not accidentally left unlatched when tilting of sash  12  is not desired and window  10  is locked. 
     Although most tilt latches slide back and forth in ways similar to the one shown in the embodiment of FIGS. 2-8, it is also possible for a tilt latch combined with a sweep lock to rotate in and out of latched position as shown in the embodiment of FIGS. 9-14. There, sweep lock  30  and lock receiver  32  have essentially the same form as shown for the embodiment of FIGS. 2-8; but tilt latch  70  is mounted to pivot, and housing  71  is altered to accommodate pivotal latching and unlatching. A manually grippable projection  74  extending above housing  71  allows tilt latch  70  to be lifted to the unlatched position shown in FIGS. 11 and 14. Tilt latch  70  can also be manually moved downward to the latched position shown in FIGS. 9,  10 ,  12 , and  13 . Detents are preferred for holding tilt latch  70  in both latched and unlatched positions so that tilt latch  70  will not become unlatched while a sash is moving downward and will not relatch by gravity from an unlatched position. 
     A cam end  78  of tilt latch  70  engages surface  35  of sweep lock  30  in the locked position so that surface  35  prevents manual unlatching of tilt latch  70  whenever sweep lock  30  is locked. Cam surface  35  can also be configured so that when sweep lock  30  moves from an unlocked to a locked position, it automatically moves under cam end  78  of tilt latch  70  to force tilt latch  70  downward into a latched position. 
     The operation of the embodiment of FIGS. 9-14 is functionally similar to the operation of the embodiment of FIGS. 2-8. The main difference is in the manual actuation of tilt latch  70 , based on a lifting and lowering motion that is possible only when sweep lock  30  is unlocked. Moving sweep locks  30  to an unlocked position leaves tilt latches  70  latched, as is desired according to the invention. When sash  12  is to be tilted, sweep locks  30  are unlocked, tilt latches  70  are lifted, and then sash  12  is free to move upward and tilt within window  10 .