Note: Descriptions are shown in the official language in which they were submitted.
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COUNTER BALANCE SYSTEM FOR A WINDOW HAVING SIDE
LOADING SASHES
10 BACKGROUND OF THE INVENTION
I. Field Of The Invention
In general, the present invention relates to
counterbalance systems that are used to hold the
sashes of a window open. More particularly, the
present invention relates to counterbalance systems
that are used in window assemblies having side-loading
sashes.
2. Prior Art Description
There are many types of windows used in modern
construction. Some windows are designed to open, some
are not. Of the windows that are designed to open,
some windows have sashes that open vertically and
others have sashes that slide open laterally, or
rotate outwardly.
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Windows that have vertically opening sashes are
the most common window used in residential home
construction. Vertically opening windows are either
single-hung, having one sash that opens, or double-
,
hung, having two sashes that open. In both single-hung
and double-hung windows, the same system is used to
hold a window sash up once it is open. If no system is
used, gravity causes the sash of the window to close
as soon as it is opened and released.
In low quality windows, friction between the
window sash and the window frame is relied upon to
hold a sash open. Such a system is highly unreliable
because the friction relied upon varies as parts wear,
expand, contract and are painted. It is for this
reason that most single and double-hung windows are
manufactured with counterbalance systems.
Early window sash counterbalance systems were
simply weights that were attached to the sash. The
weights were attached to a sash by a rope or chain
that passed over a pulley at the top of the window
frame. Such old counterbalance systems are exemplified
by U.S. Patent No, 3,160,914 to Brienza, entitled Sash
Weight Mounting Means. Such counterbalance systems
required window wells in which the weights move.
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Accordingly, such windows were difficult to insulate.
Additionally, the rough opening needed for the window .
had to be much larger than the window sashes. Finally,
window sashes attached to such counterbalance systems
could not be tilted for cleaning or otherwise removed
from the window frame.
Recognizing the many disadvantages of window well
counterbalance systems, windows were manufactured with
spring loaded counterbalance systems. Spring loaded
counterbalance systems relied upon the pulling
strength of a spring, rather than a hanging weight, to
counterbalance the weight of a window sash.
Accordingly, window wells for weights were no longer
required.
Counterbalancing a window sash with a coil spring
is a fairly simple matter. One end of the coil spring
is attached to the window frame while the body of the
coil spring is engaged by the sash. One of the
simplest examples of a coil spring counterbalance
system is shown in U.S. Patent No. 2,732,594 to Adams,
entitled Double Hung Window Sash. The difficulties
with such a system occur when a window manufacturer
wants to use coil springs to counterbalance a window
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sash while simultaneously making a window tiltable or
removable for cleaning.
In modern tilt-in windows, the window sash tilts
for cleaning but never completely leaves the window
frame. Counterbalancing such windows can, therefore,
be accomplished by attaching coil springs to the end
of the window sash that never leaves the frame.
Counterbalancing a window with a sash that is
removable is far more difficult. In a window with a
removable sash, the counterbalance system must have
the ability to connect and disconnect from the sash.
The counterbalance system commonly used for a side
loading window with a removable sash is a "block and
tackle" counterbalance. A block and tackle
counterbalance contains pulleys, string and a spring
that maintains tension on the string. The end of the
string is typically attached to the window sash with a
clip. When a window sash is being removed completely
from a window frame, the clip must be manually
detached from the sash. Once detached, the sash can be
removed while the block and tackle counterbalance
system remains behind in the jamb of the window frame.
Prior art block and tackle counterbalance systems are
exemplified in U.S. Patent No. 6,745,433 to Newman,
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entitled Side Load Balance Cord Terminal Clip; U.S.
Patent No. 4,697,304 to Overgard, entitled Friction
Controlled Window Balance, and U.S. Patent No.
4,089,085 to Fitzgibbon, entitled Sash Balance and
Components Thereof.
There are many problems associated with prior art
block and tackle counterbalance systems. First, a
block and tackle counterbalance system must be custom
designed to correspond to a particular window sash
height and/or weight. Different block and tackle
counterbalance assemblies must therefore be
manufactured to accommodate sashes of different sizes
and different weights. Furthermore, block and tackle
counterbalance systems are complex assemblies that
contain several moving parts. These parts are
difficult to assemble and are subject to failure over
time. Consequently, block and tackle counterbalance
systems tend to be expensive to manufacture and have
limited reliability. Another disadvantage of block and
tackle counterweight assemblies is that they are
difficult to detach and reattach to a window sash and
can easily cause injury to an inexperienced person who
attempts the task.
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A need therefore exists for a counterbalance
system that can be used in a window assembly with a
side loading sash, wherein the counterbalance system
does not use a complex block and tackle construction,
is versatile to many window sizes, is simple to attach
and detach, and is both simple and inexpensive to
manufacture. This need is met by the present invention
as described and claimed below.
SUMMARY OF THE INVENTION
The present invention is a counterbalance system
for a side load window assembly. The side load window
assembly has a window frame with side jambs. At least
one window sash is held in the window frame, wherein
the window sash is free to be selectively opened and
closed. The window sash has a top, a bottom and two
vertical sides. When the sash is installed into the
window frame, it assumes an operable position where
the vertical sides of the window sash are aligned with
/0 the side jambs of the window frame. When the sash is
in its operational position, a gap space exists
between the vertical sides of the window sash and the
side jambs of the window frame. This gap space is
utilized by the counterbalance system.
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The counterbalance system includes a spring
carriage. The spring carriage has a first section that
fits into the gap space between the window frame and
the window sash. The spring carriage also includes a
second section that passes under a portion of the
bottom of the window sash, therein supporting the
window sash when the window sash is in its operable
position.
At least one coil spring is provided. Each coil
spring has a wound body that is held within the
confines of the spring carriage. Each coil spring also
has a first end that extends out of the spring
carriage. The first end of each coil spring is
anchored to one of the side jambs of the window frame.
The coil springs bias the spring carriage
upwardly. Since the window sash rests upon the spring
carriage, the window sash is counterbalanced. The
window sash only rests upon the spring carriage and
can be lifted away from the housing. Consequently, the
counterbalance system provides a counterbalancing
force for a window sash without inhibiting the window
sash from being removed from the window assembly.
Locking mechanisms are used to hold the spring
carriages in place as the window sashes are removed.
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The loading mechanisms are side lock assemblies that engage
locking depressions in the window jambs. The slide lock
assemblies include a locking element that slides into the
locking depression and a spacer that wedges the locking element
into space. In accordance with an aspect of the present
invention, there is provided a side load window assembly,
comprising: a window frame having side jambs, wherein a locking
depression is formed in each of the side jambs; a window sash having a
top, a bottom and two vertical sides, the window sash being
selectively positionable into an operable position where the vertical
sides of the window sash are aligned with the side jambs of the window
frame, and wherein a gap space exists between the vertical sides of
the window sash and the side jambs of the window frame when the window
sash is in the operable position;a slide lock; a spring carriage
having a top section and a base section integrally formed as a single
piece, wherein the top section is sized to fit into the gap space
between the window frame and the window sash, and wherein the base
section is elongated and creates a lateral sill that passes under a
portion of the bottom of the window sash, therein supporting the
window sash when the window sash is in the operable position; wherein
the top section of the spring carriage defines at least one spring
compartment; and wherein the bottom section of the spring carriage
defines a compartment under the lateral sill that receives the slide
lock, therein enabling the slide lock to selectively move back and
forth between a retracted position and an extended position; wherein
when the slide lock engages the locking depression in the side jamb
when moved to the position as the window sash is opened to a
predetermined height, therein mechanically interconnecting the
carriage housing to the side jamb; and, a coil spring retained in each
spring compartment of the spring carriage, wherein each the coil
spring has a first end extending from the spring carriage, wherein the
first end of each the coil spring is anchored to one of the side jambs
of the window frame.
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In accordance with another aspect of the present invention, the
window sash is separable from the spring carriage by lifting the
window sash up and off the second section of the spring carriage.
In accordance with another aspect of the present invention the
window sash is free of the side jambs once separated from the spring
carriage.
In accordance with another aspect of the present invention the
window assembly the invention comprises a window sash positioned
between two window frame jambs, wherein a gap space exists between the
window sash and the window frame jambs, a counterbalance system for
the window sash comprising: a spring carriage having a top section
and a base section integrally formed as a single piece, wherein the
top section is sized to fit into the gap space between the window
frame jambs and the window sash, and wherein the base section is
elongated and creates a lateral sill upon which part of the window
sash rests when positioned between the two window frame jambs; wherein
the top section of the spring carriage defines a spring compartment;a
coil spring having a wound body from which a first end of the coil
spring can be drawn, the wound body being carried by the spring
compartment of the spring carriage in the gap space between the window
sash and the window frame jambs, wherein the first end of the coil
spring is anchored to one of the window frame jambs.
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In accordance with another aspect of the present invention the
assembly further comprises a locking mechanism for selectively
connecting the spring carriage to one of the window frame jambs in a
fixed position.
In accordance with another aspect of the present invention the
locking mechanism includes a slide lock that extends from the spring
carriage and engages one of the window frame jambs.
In accordance with another aspect of the present invention, the
spring carriage defines and/or comprises multiple spring compartments
and multiple wound bodies of coil springs are retained by the spring
carriage.
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BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present
invention, reference is made to the following.
description of an exemplary embodiment thereof,
considered in conjunction with the accompanying
drawings, in which:
FIG. 1 is a perspective view of an exemplary
embodiment of a side load window assembly containing a
counterbalance system;
FIG. 2 is an exploded view of the counterbalance
system shown utilized in Fig. 1;
Fig. 3 is a cross-sectional view of the
counterbalance system shown unlocked and with the
window sash in its operational position;
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FIG. 4 is a cross-sectional view of the
counterbalance system shown partially locked and with
the window sash in its operational position;
FIG. 5 is a cross-sectional view of the
counterbalance system shown in a fully locked
condition and with the window sash being removed.
DETAILED DESCRIPTION OF THE DRAWINGS
Although the present invention counterbalance
system can be used to counterbalance the sashes in a
double-hung window, the exemplary embodiment selected
for illustration shows a single-hung window. The
choice of a single-hung window was made simply for
ease of illustration purposes and should not be
considered a limitation upon the invention as claimed.
Referring to both Fig. 1 and Fig. 2, there is
shown a window assembly 10. The window assembly 10 has
a window frame 12 that retains both an upper sash (not
shown) and a lower sash 16. As has been previously
stated, the window assembly 10 is being illustrated as
a single-hung window, meaning that only the lower sash
16 can be opened.
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The window assembly 10 is constructed to be a
"side load" window. A side load window is a,common
window type where one or more of the sashes can be
selectively removed from the window frame. For a
variety of reasons, side load windows are commonly
used in the construction of many types of replacement
windows.
In a side load window, a sash can be completely
removed. In the shown exemplary embodiment, the lower
sash 16 has side load features and is removable.
Depending upon the size of the window assembly 10, the
window sash 16 may have a weight of between five
pounds and fifty pounds. Furthermore, the window sash
16 may have a length and height that varies between
one foot and three feet.
When the window sash 16 is loaded into the window
frame 12, it enters its operable position. In its
operable position, the window sash 16 can be
selectively opened and closed by being slid up and
down. To prevent the window sash 16 from closing under
the force of its own weight, it must be
counterbalanced. A counterbalance system 20 is
provided to retain the window sash 16 in an open
position. The counterbalance system 20 is especially
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designed for side load windows. Furthermore, the
counterbalance system 20 is highly versatile, wherein
a single counterbalance system can be adapted for use
in window assemblies having sashes in a wide variety
of sizes and weights.
Referring to Fig. 2 in conjunction with both Fig.
3, it can be seen that the window frame 12 has side
jambs 22. Each of the side jambs 22 defines a primary
channel 24 in which the window sash 16 rides. Each
primary channel 24 is defined by a back surface 26
that lay perpendicular to the plane of the window sash
16 and two side surfaces 27, 28 that lay in planes
parallel to the plane of the window sash 16. A locking
depression 30 is formed in the back surface 26 of the
primary channel 24 at a predetermined position. The
purpose of the locking depression 30 is later
described.
The window sash 16 has a width that is sized to
pass into the primary channel 24 of the side jamb 22.
/0 The window sash 16, therefore, rides within the
primary channel 24 as it moves up and down. The front
and rear surface 31, 32 of the window sash 16 extend
beyond the vertical sides 34 of the window sash 16.
This creates a secondary channel 36 along the sides 34
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of the window sash 16. When the window sash 16 is
installed into the window frame 12, the secondary
channel 36 along the window sash 16 faces the primary
channel 24 along the side jamb 22. This creates a gap
space 40 between the window sash 16 and the side jamb
22. The gap space 40 is utilized to hold the
counterbalance system 20, as is explained below.
The counterbalance system 20 relies upon coil
springs 42 to counteract the weight of the window sash
16. However, the coil springs 42 are not directly
attached to the window sash 16. Rather, the
counterbalance system 20 utilizes a spring carriage 44
that holds the wound body 46 of the coil spring 42.
The spring carriage 44 extends into the gap space 40
between the side jamb 22 and the window sash 16. The
spring carriage 44 supports the weight of the window
sash 16 and transfers that weight to the coil springs
42.
The spring carriage 44 includes a housing 50. The
housing 50 has a top section 52 and a base section 54.
The top section 52 is narrow and is sized to fit into
the gap space 40 that exists between the side jamb 22
and the window sash 16. To prevent the top section 52
from moving within the gap space 40 and making noise,
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the top section 52 includes a spacer flange 55. The
spacer flange 55 has a width just slightly smaller
than the back surface 26 of the primary channel 24.
The spacer flange 55 rides between the side surfaces
27, 28 of the primary channel 24 and keeps the housing
50 in its proper orientation.
The base section 54 of the housing 50 is longer
than the top section 52 and does not fit into the gap
space 40. Rather, the base section 54 has a lateral
sill 56 that extends under the window sash 16 so that
the window sash 16 rests upon the lateral sill 56,
whereby the lateral sill 56 supports the weight of the
window sash 16.
A bottom groove 58 is present on the bottom of
the window sash 16. The bottom groove 58 receives the
lateral sill 56 extending from the spring carriage
housing 50. Only gravity holds the window sash 16 in
place upon the lateral sill 56 of the spring carriage
housing 50. It will therefore be understood that the
window sash 16 can be lifted upwardly off the lateral
sill 56.
The spring carriage 44 defines at least one
spring compartment 48. In the shown embodiment, a
plurality of spring compartments 48 are shown. Each of
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the spring compartments 48 holds the wound body 46 of
a coil spring 42. Each coil spring 42 has a free end
45. The free end 45 of each coil spring 42 extends out
of the housing 30 and up the back surface 26 of the
primary channel 24 in the side jamb 22. The number of
coil springs 42 that are used is dependent upon the
weight of the window sash 16. For example, if each
coil spring 42 provides a counterbalance force of five
pounds, and a window sash 16 weighs twenty pounds,
then a total of four coil springs 42 would be used,
two on each side of the window sash 16.
The free ends 45 of the coil springs 42 are
anchored to the back surface 26 of the primary channel
24 at some high point along the side jamb 22.
Accordingly, as each coil spring 42 unwinds, the
natural curvature associated with the coil spring 42
causes the unwound sections of the coil spring 42 to
press against the back surface 26 of the primary
channel 24. The unwound sections of the coil springs
/0 42 are therefore kept flush against the back surface
26 of the primary channel 24. The coil springs 42
provide an upward bias to the window sash 16 that
counterbalances its weight. Accordingly, the window
sash 16 will stay in position once opened.
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The base section of 54 of the spring carriage 44
defines a horizontal channel 59. A slide lock assembly
60 is disposed in the horizontal channel 59. The slide
lock assembly 60 is a two-part assembly that contains
both an elongated lock element 61 and a sliding spacer
62. Both the elongated lock element 61 and the sliding
spacer 62 can move back and forth within the
horizontal channel 59. When the window sash 16 is
installed in the window frame 12, the slide lock
assembly 60 does nothing. The slide lock assembly 60
is retracted into the base section 54 of the spring
carriage 44 and does not effect the movement of either
the window sash 16 or the spring carriage 44.
The elongated lock element 61 and the sliding
spacer 62 interconnect to form the slide lock assembly
60. The elongated lock element 61 has a groove 63 on
its bottom surface that is sized and shaped to receive
the sliding spacer 62. The groove 63 enables the
sliding spacer 62 to move within the elongated lock
element 61. It will therefore be understood that
although the entire slide lock assembly 60 can
reciprocally move within the horizontal channel 59,
the sliding spacer 62 can also move relative the
elongated lock element 61.
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The sliding spacer 62 has a knob 64 that extends
below the elongated lock element 61. When the slide
lock assembly 60 is positioned within the horizontal
channel 59, the knob 64 extends cut of the horizontal
channel 59 through an open slot 65. The knob 64
enables a person to selectively move the slide lock
assembly 60 back and forth in the horizontal channel
59 using manual force. When the knob 62 is manually
moved in one direction (to the right in the
illustration), the distal end 66 of the elongated lock
element 61 extends laterally out of the horizontal
channel 59.
Referring to Fig. 4 in conjunction with Fig. 3
and Fig. 2, it will be understood that when the window
sash 16 is opened to a predetermined height, the slide
lock assembly 60 can be made to align with the locking
depression 30 in the back surface 26 of the primary
channel 24. Once aligned, the distal end 66 of the
elongated lock element 61 can be manually moved into
the locking depression 30.
When the distal end 66 of the elongated lock
element 61 enters the locking depression 30 in the
primary channel 24 of the side lamb 22, the spring
carriage 44 becomes mechanically interconnected to the
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side jamb 22. Accordingly, the spring carriage 44 can
no longer be moved. The locking depression 30 is
larger than the distal end 66 of the elongated lock
element 61. This enables the distal end 66 of the
elongated lock. element 61 to easily pass into the
locking depression 30. This is shown in Fig. 4.
However, the loose interconnection also has a
disadvantage in that the distal end 66 of the
elongated lock element 61 can also easily be moved out
of the locking depression 30.
Referring to Fig. 5 in conjunction with Fig. 2,
it can be seen that one the distal end 66 of the slide
lock assembly 60 is in the locking depression 30, the
sliding spacer 62 can also be moved into the locking
depression 30. The sliding spacer 62 takes up all the
slack between the elongated lock element 61 and the
locking depression 30. The, addition of the sliding
spacer 62 acts as a wedge to lock the elongated lock
element 61 into the locking depression 30. This
prevents the elongated lock element 61 from
inadvertently disengaging from the locking depression
30.
Once the spring carriage 44 is locked in a. fixed
position, the window sash 16 can be lifted away from
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the spring carriage 44. Once lifted to a height where
the window sash 16 is free of the spring carriage 44,
the window sash 16 can be removed from the window
assembly.
Each spring carriage 44 used in the present
invention counterbalance system 20 can hold between
one and four coil springs 42. It will therefore be
understood that the counterbalance system 20 can be
adapted for use with many different sizes and weights
of windows sashes. Heavy window sashes require more
coil springs, lighter window sashes require less.
Regardless, the spring carriage 44 and the engagement
between the window sash 16 and the spring carriage 44
remain the same. A single, low-cost spring carriage 44,
in combination with varying numbers of coil springs 42
can therefore be used to counterbalance most any
window assembly having jambs and window sashes
configured for side loading.
It will be understood that the embodiment of the
/0 present invention that is described and illustrated is
merely exemplary and that a person skilled in the art
can make many variations to the invention using
functionally equivalent components. For instance, the
slide lock can be reconfigured in many ways. The
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spring carriage can be configured to hold only one,
three, or four coil springs, rather than the two
illustrated. All such variations, modifications and
alternate embodiments are intended to be included
within the scope of the present invention as defined
by the claims.
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