Removable locking lever for a casement window

A casement window locking system includes a rotatable locking cam mounted in the frame jamb with a window catch access opening on one side and a locking lever access opening on the opposite side. The locking lever has a U-shaped inner end which embraces the locking cam when the two members are engaged and a tab on the locking cam engages a shoulder on the locking lever to prevent withdrawal of the locking lever until a tool is used to raise the locking cam when the tool is inserted through the catch opening. In an alternative embodiment, a spring clip may be placed on top of the locking cam and it includes a shoulder for engaging the shoulder on the locking lever. The removable locking lever makes it possible to install and finish the window without the locking lever and change locking levers to color coordinate with the room interior.

BACKGROUND OF THE INVENTION 
Casement window locking systems are customarily riveted assemblies which 
are secured to the window frame jamb with screws in an exposed manner. The 
Rolscreen Company of Pella Iowa has used a one piece cam and handle 
locking system that is secured to and contained within the window frame 
jamb. A partially exposed locking system has been used wherein the handle 
was secured with a set screw to a splined stud attached to the concealed 
locking cam. Loosening of the set screw would allow accidental removal of 
the handle rendering the window unsafe if it was needed to open it in an 
emergency. 
Whether the locking system is on the exterior of the frame jamb or 
contained within it, the handle or lever must be in place to operate the 
lock to hold the sash closed during building construction and finishing, 
including the finishing of the window. 
A locking system is needed that will allow the installation of the exposed 
portions of the locking mechanism after finishing is completed. The 
locking system should provide for interchangeability of handles for 
purposes of color coordinating with interior room decorating at any time 
after the window is manufactured and installed. 
SUMMARY OF THE INVENTION 
A casement window locking mechanism is provided that includes essentially 
two parts. The first part is a rotatable cam which is mounted in the frame 
jamb and which engages a catch on the window when in its closed position. 
The frame jamb has oppositely disposed access openings to the locking cam. 
The catch on the window can extend into or is received in an outer access 
opening while the locking lever is received in the inwardly facing access 
opening. When the locking lever is in place, the locking cam is not 
visible through the inner access opening. A tab on the locking cam engages 
a shoulder on the locking lever to prevent removal of the locking lever. A 
spring on the locking cam yieldably maintains engagement between the tab 
and the shoulder. When the locking lever is inserted into the inner access 
opening, the locking tab is deflected inwardly and rides up a beveled 
surface whereupon it engages the shoulder locking the lever in place. 
Disengagement of the locking lever from the locking cam is possible through 
operation of a tool such as a screwdriver which is placed under the 
locking cam or tab whereby it is moved out of engagement with the locking 
lever shoulder allowing removal of the locking lever. The spring may be a 
curved spring on the screw holding the cam to the frame jamb or a spring 
clip on top of the cam which has a tab on its outer end for engagement 
with the shoulder on the locking lever. 
The locking mechanism of this invention allows for a simplified 
installation of the window including the finishing of the window frame 
with the locking lever removed. After the window has been fully installed 
and finished, the locking lever may be installed for operation of the 
locking mechanism. As the decorating of the interior of the room changes, 
the locking lever can be changed as desired to provide color coordinated 
window hardware. It is also seen that the window may be temporarily 
operated through the use of the installed locking lever during 
construction and then removed as construction work continues. It is 
important that the locking lever can only be removed when the window is in 
its opened position a only then is access possible to the cam opening in 
the frame jamb. Thus, the locking lever is always in place and ready for 
use when the window is closed assuring that for safety reasons there is 
never a time when the window can't be opened.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The casement window locking system of this invention is referred to 
generally in FIG. 1 by the reference numeral 10 and is shown mounted in 
the window frame jamb 12. A casement window 14 is hinged on the opposite 
window frame jamb (not shown) allowing a catch 16 to be received in an 
exterior or outer access opening 18 as seen in FIG. 9 for engagement by a 
cam 20 which may be rotated by a locking lever 22. The locking lever 22 is 
received in an interior access opening 24 in the window frame jamb 12. The 
window frame jamb 12 includes an outer portion 26 and an inner portion 28 
which provide containment for the locking cam 20 leaving only portions of 
the locking lever 22 exposed through the interior access opening 24 when 
the locking lever is installed as seen in FIG. 1. 
The locking cam 20 includes a base portion 30 having opposite sides 32 and 
34 and an end edge 36 opposite a cam portion 38 engageable with the sash 
catch 16. A screw 40 extends through a curved spring washer 42 which 
presses on the top of the cam 20 for maintaining engagement with the 
locking lever 22 as hereinafter described. Screw 40 is anchored in the 
outer frame jamb portion 26. As seen in FIG. 5, an outwardly extending tab 
44 extends in the opposite direction from the cam portion 38. 
Referring to FIG. 8, it is seen that the locking cam 20 has a center body 
portion 46 with outwardly extending wings or edges 32 and 34. The center 
body portion 46 is supported on a spacer 50 received in a channel 52 in 
the outer portion 26 of the window frame jamb 12. 
The locking lever 22 includes an outer end handle portion 53 and an inner 
end 54 which is U-shaped and includes a base portion 56 with oppositely 
disposed legs 58 and 60 defining a slot 62. A channel 64 is formed in the 
leg 60 and includes a shoulder 66. The legs 58 and 60 are spaced to 
matingly engage the side edges 32 and 34 of the locking cam 20 while the 
edge 36 engages the base portion 56. When assembled, the shoulder 66 is 
below the tab 44. Tab 44 is positioned to engage an outwardly tapering 
portion or surface 68 and continued movement of the locking lever 22 
towards the cam 20 causes the tab 44 to drop into the channel 64 locking 
it against the shoulder 66. The curved spring 42 on the screw 40 maintains 
the engagement of tab 44 with shoulder 66. 
As seen in FIG. 6, a screwdriver 72 may be inserted under the cam portion 
38 and on top of the tapered portion 68 whereby twisting of the 
screwdriver will raise the locking cam 20 thereby disengaging the tab 44 
from the shoulder 66 and allowing the locking lever 22 to be moved in the 
direction of the arrow 74 in FIG. 4. 
In FIGS. 4 and 8, it is seen that a flange portion 76 on the legs 58 and 60 
and the base portion 56 extend under the wings or edges 32 and 34 and end 
edge 36 of the cam 20 to provide an embracing nesting relationship between 
the locking lever 22 and the cam 20. 
In FIGS. 10-15, an alternate embodiment is shown wherein a spring clip 78 
is substituted for the curved spring washer 42. The clip 78 includes a 
plate element 80 having a hole 82 for being mounted on the screw 40 on top 
of the locking cam 20a. A perpendicularly extending tab 84 on the clip 78 
includes right angle shoulders 86 and 88 with the shoulder 86 positioned 
to engage the shoulder 66 on the locking lever 22 and the shoulder 88 
positioned to engage a screwdriver 72 as seen in FIG. 14. Thus it is seen 
in operation that the locking lever 22 is assembled with the locking cam 
20 in the same manner as it was in connection with the embodiment of FIGS. 
1-9, except that the shoulder 86 on the spring clip 78 replaces the tab 44 
on the locking cam 20 in engagement with the shoulder 66 on the locking 
lever 22. In disengaging the locking lever 22 from the locking cam 20, the 
screwdriver is placed under the shoulder 88 on the spring clip 78 rather 
than under the cam portion 38 of the cam 20. The embodiment of FIGS. 1-9 
is simplified by the elimination of one component, i.e. the special spring 
clip 78.