Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to sliding sash windows.
More particularly this invention relates to a sa~ety lock to
allow a sliding sash window to be locked in the partially open
position.
The majority of sliding sash windows made today have
metal frames, generally formed from extruded aluminum sections
Sliding sash window assemblies have an inner sash and an outer
sash. In some cases when a double window is provided there are
two inner sashes and two outer sashes together with a :ely screen.
All the sashes are removable as well as the fly screen which
slides in a track in the aluminum section to leave a completely
open window i~ desired. Removable sashes enables the windows
and ~rames to be cleaned. Vertical sliding sash windows are
generally provided with spring counter-balances at the sides of
each sash to hold the sash in any position in the window frame.
Because the sashes are removable, it is necessary to have a system
for releasing these spring countsr-balances from the sash before
the sash is removed from the frame
Most sashes are provided with a lock which either locks
the sash to the frame, or alternatively, locks two sashes to-
gether, when both sashes are ~ully closed. With a vertical
sliding sash window having spring counter-balances, it is
difficult to provide a lock at the side to lock the sash to the
frame and, therefore, the sash is either locked in the closed
position to the top or bottom o~ the frame, or the two sashes
are locked together when closed. There is no room for locks at
the side o~ the sash because the spring counter-balances take up
the available space.
The present invention provides a simple safety lock
which allows one sash to be opened a small amount relative to
the other sash to provide ventilation into a room The safety
lock of the present invention provides either the outer sash
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to be opened, or the inner sash to be opened, or alternatively,
both sashes to be opened a small amOUDt The opening is
sufficiently small to prevent access into a room from outside.
Thus a safety feature is provided that ventilation can be obtained
in a room without leaving a window fully open, but the window
can be locked to prevent entry from outside.
Furthermore, the present invention provides a safety
lock :Eor a vertical sliding sash window, the lock being mounted
in one of the top corners of the lower inner sash in a location
where it does not interfere with the spring counter-balance and
engaging with a detent provided on the frame of the upper sash.
The safety lock has a corner section having a lip to engage the
spring counter-balance for the inner sash, but allows the counter~
balance to be disconnected if it is desired to remove the sash
from the frame. Only one sa~ety lock is required, thus each
sash may be removed from the frame after both spring counter-
balances have been disconnected from the sash.
The present invention provides a safety lock for a
sliding sash window, having an inner sash and an outer sash,
comprising a sliding lock pin located in one corner of the inner
sliding sash on a surface normal to the direction of movement
of the sliding sash, a corner section at the corner of the inner
sliding sash, having a passage for the sliding lock pin to move
into a locked position with the outer sash, and a detent located
in the outer sash to engage with the sliding lock pin when in
the locked position, the detent positioned so that the inner sash
may move a predetermined distance relative to the out~r sash
before the lock pin engages the detent
In drawings which illustrate embodiments o~ the
present invention,
Fig. 1 is an elevational view of a vertical sliding
sash window.
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Fig, 2 is a horizontal section taken at line 2~2 of
~ig. 1.
Fig. 3 is a vertical section taken at line 3-3 of
Fig. 1.
Fig. 4 is a partial vertical section taken at line
4-4 of Fig. 3.
Fig. 5 is a partial vertical section taken at line
5-5 of Fig. 2.
Referring now to the drawings, Fig. 1 illustrates a
window frame 10 for a vertical sliding sash window, with an
inner lower sash 11 and an outer upper sash 12, One of the top
corners of the lower sash 11 has a safety lock 13 according to
the present invention, and a detent 14 is provided in the frame
of the upper sash 12 to mate with the sliding lock 13.
As shown in Fig. 2 the lower sash 11 has spring counter-
balances 15 on each side, The upper sash 12 also has spring
counter-balances 16 positioned at each side of the sash. The
counter-balances 15 and 16 fit into U-shaped channels 17 which
form frames for the sashes. As illustrated more clearly in
~O Fig. 4 the spring counter-balance 15 is telescopic in exterior
appearance, having a spring therein, fits into a lip at the top
of the U-shaped channel 17 and at the base the counter-balance
is attached to the frame 10. In all standard sliding sash
windows provision is made to lock the spring counter-balance 15
to the frame 10 so that the sash may be raised free from the
spring counter-balances, moved to one side in the fIame and
sufficient room is available for the sash to be pulled out of the
frame at the other side and then be completely removed ~rom the
frame. As may be seen in Fig. 3, whereas the side~ of each
sash is a U-shaped channel 17, the top and bottom members of
each sash are square section members 18 which mate with the
U-shaped channel 17 to form a sash frame,
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As illustrated in more detail in Figs. 4 and 5 the
safety lock 13 includes a sliding lock pin 20 having an operating
end 21 adapted to be pushed by an individual and an engagement
end 22 slightly cup-shaped to engage with the detent 14, A
keeper plate 23 on the base o~ the locking pin 20 restricts the
movement of the locking pin in the sash frame, A corner section
25 fits in the top corner of the sash ~rame, at one side but not
both sides of the lower sash 11, The corner section 25 has a pass-
age 26 for locating the sliding lock pin 20. A spring clip 27,
presses against the lock pin 20 so that it remains in any
position in the passage 26, The corner piece 25 i5 formed
integrally into the corner where the square section 18 and U-
shaped channel 17 join, A lip 28 is provided beneath the passage
26 supporting the lock pin 20, into which fits an end 29 of the
spring counter-balance 15, A guide surface 30 also formed in the
corner section 25 retains the spring counter-balance 15 in its
desired position. Thus the spring counter-balance at its top
rests within the U-shaped channel 17 of the sash,
The detent 14 is cut in the side of the U-shaped
channel 17. Nothing protrudes inside the U-shaped channel 17
to interfere with the spring counter-balance 16, A portion is
pushed out sufficiently far to engage the cup portion 22 of the
lock pin 20, but not suf~iciently far that it interfers with
the movement between the lower sash 11 and the upper sash 12,
The location of the detent 14 is such that the window may open
approximately 6". This distance may be varied depending on
particular requirements. 6" is believed to be a good distance as
it is insufficient for anyone to climb in through a window and
yet does permit ventilation,
The U-shaped channel 17 and the square section 18
forming the sash are pre~`erably made of extruded aluminum shapes
and are standard for both upper and lower sashes. Furthermore,
the frame sections 10 are also standard extruded aluminum
sections. Whereas single glazing is shown in the drawings, it
will be apparent that double glazing can equally well be
incorporated.
In operation with the locking pin 20 pulled out to its
fullest extent, the lower sash 11 and upper sash 12 have free
movement without any inter~erence, In order to engage the sliding
lock pin 20, the upper sash 12 is moved to its uppermost position.
The lower sash 11 is moved to its lowermost position. The lock
pin 20 is then pushed in until the cup-shaped portion 22 is
resting against the surface of the U-shaped channel 17 of the
upper sash 12. The lower sash 11 may then be raised until the
cup-shaped portion 22 of the lock pin 2Q engages with the detent
14, This provides an opening beneath the lower sash 11. If
desired, the upper sash 12 may be moved downwards. This moves
the lower sash 11 because the force will be transferred through
the detent 14 and the lock pin 20, Openings may remain at the
top and the bottom. Alternatively, the upper sash 12 may be
moved down until the bottom of the lower sash 11 touches the
frame. This provides an open space at the top o~ the upper sash
12 rather than at the bottom of the lower sash 11.
To remove the lower sash 11 from the frame 10 it is
necessary to first disconnect the two spring counter-balances 15
at each side of the sash. This is done in a well known fashion.
Locking pins (not shown) are provided to hold the spri~g
counter-balances in the compressed position. The lower sash 11
is then raised and the sash moved to the left away from the
safety lock 13, until the side of the lower sash 11 is clear o~
the ~rame 10. This side of the sash is then pulled forward and
the sash can be completely removed from the frame. It is
preierred not to have safety locks on both sides of the sash,
because if that occurs then it is not possible to remove the
.
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sash from the frame in the manner described, because the lock
pin 20 prevents the sash at one side being pushed into the frame,
Various changes may be made to this invention without
departing from the scope thereof, The shape o~ the sliding
lock pin 20 may be changed, rather than a sliding lock pin it
could be a swivel lock pin, rather than a detent in the side of
the sash frame a hole could be provided for a permanent lock,
The important feature being that the safety lock is provided in
such a manner that it does not interfere with the operation of
a sliding sash window, Neither does it interfere with the
operation of the spring counter-balan~e in both the upper sash
and lower sash, The safety lock of the present invention may be
applied to horizontal sliding sash windows in the same manner
as vertical sash windows, It may also be applied to sliding
doors in the same manner, In the case of horizontal sliding
windows or doors there is generally not a spring counter-balance
provided, so the space requirement is not so much of a problem,
however, the present concept of a safety lock provides the
standard sections of sash or door frame without requiring holes
to be drilled for insertion of locks, etc.
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