Casement window sash locking system

A casement sash locking system including locking assembly, drive assembly and lock strike that can be mounted on either side allowing the window to open from the left side or right side. The locking assembly includes a lock catch that functions to first lift the outer free end of the sash and then pull the sash to a closed position, thereby preventing drag of the sash on the window frame sill.

BACKGROUND OF THE INVENTION 
Casement windows are hinged on one vertical edge to the jamb of a window 
frame allowing the opposite vertical edge to swing outwardly from the 
window frame. These kinds of windows, while having many attractive 
features, do present certain problems. The outer free vertical edge of the 
sash may drop over a period of time since it is cantilevered from the 
hinged window jamb, thereby causing drag when the sash is closed against 
the window frame sill. 
Typically the casement type window will involve a locking assembly on the 
jamb adjacent the free edge of the sash, but the locking assembly will 
oftentimes be too high to be readily reached when windows are over sinks, 
counters, etc. 
A related problem is that ideally the window should be capable of being 
deactivated for security reasons. 
The locking systems typically used are limited in application due to the 
substantial space required for the locking mechanism. 
Thus, it is seen that a locking system for casement windows is needed that 
will obviate any sash drag that might otherwise occur, occupy a minimum of 
space, be readily accessible and include security protection. 
SUMMARY OF THE INVENTION 
The window locking system of this invention includes a catch engageable 
with a lock strike on the sash which functions to move between first and 
second positions. In the first position the catch extends outwardly and 
downwardly from the window jamb, and in moving to the second position 
pivots upwardly into engagement with the lock strike on the sash, thereby 
lifting the outer free edge of the sash such that it will clear the 
windowsill when the sash is moved to its closed position. The catch, after 
having lifted the sash, then continues towards the second position by 
pulling the sash toward the window frame to the fully-closed position. 
The preferred embodiment includes upper and lower locking assemblies and a 
drive assembly, including a handle located on the jamb below both locking 
assemblies, thereby making it readily accessible at the level of the 
windowsill. 
The lock strike is recessed into the outer free vertical edge of the sash 
and includes a housing having interior lock or strike shoulders on 
opposite sides of an access opening. The lock strike housing can be 
mounted on either vertical edge of the sash with one strike shoulder being 
utilized on one side and the other being used on the other side. The 
locking assembly and the drive assembly can be mounted on either jamb as 
most of the component parts of each are compatible to operation in either 
location. 
The drive assembly includes a rotatable cam which is removably connected to 
a handle whereby for security purposes the handle may be removed rendering 
the locking assembly inoperative. In U.S. Pat. No. 5,080,407, REMOVABLE 
LOCKING LEVER FOR A CASEMENT WINDOW, a handle is shown removably attached 
to a different kind of cam. 
The design of the components of the drive assembly and locking assembly are 
such that they can be mounted in the window jamb where space available is 
at a minimum. Drive and locking assemblies are hidden under a very thin 
frame stop. The frame stop is a 4/4(0.688 inch) as compared to previous 
frame stops which are 5/4(1.093 inch). 
The lock strike has an edge that seals against the primary weatherstrip to 
provide an air and water seal. The lock strike edge is coincident with the 
sash edge to form a continuous seal. The lock strike design in cooperation 
with the lock catch enables the lock catch to have a minimum clearance 
with the weatherstrip. The lock catch width is unique for casement windows 
in that it is only 0.090 inch thick. 
The locking assembly may be used in any orientation (such as on its side 
for awning windows) because the lock catch action is not dependent on 
gravity. The lock mechanism will force the lock catch to drop to its 
lowered and extended position. 
Additional advantages of this invention include a locking system not 
requiring a special window frame configuration, but instead only requires 
special cuts in the frame and frame stop. The locking system requires 
relatively few parts, and most of the parts are universal such that they 
can be used for left-hand or right-hand locking systems. Any number of 
locking assemblies can be operated on a single jamb by only one handle. 
The locking assembly housing has projections that engage the frame and 
frame stop, thereby transferring the load required to hold the sash closed 
to the frame and frame stop and thereby avoid the installation screws 
carrying the full load.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The locking system of this invention as seen in FIG. 3 includes a locking 
assembly 10 and a drive assembly 12 mounted on a jamb 14 in a window frame 
16. As seen in FIGS. 1 and 2, a window assembly 18 is mounted over a 
kitchen counter 20 and includes sash 22. The sash 22 includes a lock 
strike 24. 
The lock assembly 10 is seen in FIG. 4 to include a housing 26 which holds 
a lock cam 28 for operating a lock catch 30. The housing 26 is symmetrical 
in appearance and has a pair of lock catch 30 channels 32 as defined by 
oppositely disposed side walls 34 and a guide block 36. The housing 26 has 
ears 38 to receive screws 40 engageable with the jamb 14. A cap 42 may be 
snapped over the housing 26. A positioning tab 44 extends from the housing 
26. 
The lock cam 28 is circular in shape and includes a gear 46 on its bottom 
side for engagement with a rack 48 on a link 50. The top face of the lock 
cam 28 includes oppositely disposed pins 52 for engagement with the lock 
catch 30 in a vertical slot 54. The lock catch 30 includes an outer end 56 
having a hook opposite the inner end having the elongated vertical slot 
54. A longitudinally extending flange 58 extends along the bottom side of 
the lock catch 30 and is received in one or the other of the channels 32 
of the housing 26. Flange 58 is also received in the right side slot of a 
pair of oppositely disposed slots 60 extending from the periphery of the 
lock cam 28 inwardly. 
The sequential operation of the lock assembly 10 is seen in FIGS. 5, 8 and 
10. In FIG. 5 the lock catch 30 extends downwardly and outwardly in a 
first position. As the lock cam 28 is rotated clockwise as seen in FIG. 8, 
the upper wall 62 of the right-hand cam slot 60 presses down on the flange 
58 below the vertical slot 54 causing the lock catch 30 to pivot upwardly 
at its hook end 56. The fulcrum for the pivoting of the lock latch 30 is 
the point of contact of the flange 58 with the housing channel 32 bottom 
wall 34. As the lock cam 28 continues to rotate clockwise as seen in FIG. 
10, the pin 52 operating in the slot 54 pulls the lock latch 30 
horizontally inwardly to the left. The maximum inward travel is reached 
when the pin 52 reaches the nine o'clock position. 
The unlocking of the lock assembly is accomplished by rotating the lock cam 
28 in a counter clockwise direction whereupon the bottom wall 64 of the 
slot 60 on the right-hand side of the lock cam 28 as seen in FIG. 5 
presses upwardly on the bottom side of the flange 58 while the adjacent 
sidewall of the guideblock 36 in the housing 26 forming the channel 32 
presses downwardly on the top side of the flange 58 insuring that the 
catch 30 returns to its original position shown in FIG. 5. Thus it is seen 
that in moving from a fully open position of FIG. 5 to a fully closed 
position of FIG. 10 the lock cam 28 rotates 180.degree. with the pin 52 
moving from a three o'clock position to a nine o'clock position. The 
oppositely disposed cam slot 60 and pin 52, along with the opposite 
housing channel 32 are used when the locking assembly 10 is mounted on the 
opposite jamb 14A as seen in FIGS. 13 and 14. 
The lock strike 24 includes a housing 66 having an access opening 68 to an 
interior chamber 70. A pair of shoulders 72 are disposed on opposite sides 
of the access opening 68 for engagement by the hook end 56 of the lock 
catch 30. As seen in FIGS. 1-12, the hook 56 engages the upper shoulder 
72. When the lock strike housing 66 is mounted on the opposite edge of the 
sash 22 as seen in FIGS. 13 and 14, the lower shoulder 72 becomes the 
upper shoulder. The lock strike housing 66 is recessed into the outer 
vertical end edge of the sash 22 giving a flush appearance to the end edge 
and the interior surface of the sash. 
The drive assembly 12 includes a housing 74 having a vertical channel 76 in 
which a plate element 78 is received. The plate 78 includes a transversely 
extending slot 80 which receives a pin 82 on the bottom side of a drive 
handle cam 84. A handle 86 is detachably connected to the cam 84 for 
rotating the cam and in turn causing upward and downward travel of the 
plate element 78 which in turn is connected through a notch 88 to a notch 
90 in the lower end of the link 50 having the rack 48. A screw 92 extends 
through the cam 84 and the housing 74 to secure the drive assembly 12 to 
the frame jamb 14. An arcuate slot 94 in the housing 74 receives the free 
end of the pin 82 on the drive handle cam 84. A pair of strengthening and 
positioning tabs 96 are provided on the housing 74 to support the side 97 
of the channel 76 in the housing 74. 
As seen in FIG. 2, a pair of lock assemblies 10 are operated by a single 
drive assembly 12 located adjacent a windowsill 98, thus placing the 
handle 86 in a position convenient for being reached over the counter 20. 
The locking system of this invention allows for the window jamb 14 to be 
manufactured in quantity without special routing being required to 
accommodate the lock assembly 10 or the drive assembly 12. The shoulders 
and slots in these component pieces are such that they will accommodate 
these assemblies at any point along their length and thus will be mounted 
to the jamb 14 with the lock assemblies being in alignment with the lock 
strikes 24. 
The lock assembly 10 and drive assembly 12 are hidden under a very thin 
frame stop 100 as seen in FIG. 12. The frame stop 100 is routed out to 
provide recesses for receiving the lock assembly 10 and drive assembly 12. 
It is further seen in FIG. 12 that a primary weather seal 102 is provided 
on the jamb 14 which engages the outer end edge 104 of the sash 22, and 
since the outer wall of the lock strike housing 66 is coincident with the 
sash outer end edge 104, a continuous seal is provided. A secondary rain 
strip seal 106 is also provided on the frame jamb 14 for engagement with 
the outer end edge 104 of the sash 22. 
It is understood that alternate drive assembly arrangements can be utilized 
wherein the drive handle cam 84 is connected directly to the link 50 for 
operating the lock cam 28. 
In FIGS. 15 and 16 an alternate drive assembly is shown. The drive cam 84A 
includes a pin 110 which connects it directly to a rack plate link 112 
through an end 114 which is twisted 90 degrees to allow flexing as it is 
operated. The rack teeth on the plate link 112 are in the form of spaced 
apart holes 114 along the longitudinal center of the plate link. Locating 
the rack teeth 114 along the center allows for a thinner or weaker 
material to be used.