U.S. patent application number 10/280827 was filed with the patent office on 2004-04-29 for curtain wall anchor.
Invention is credited to Crooker, Robert H. JR..
Application Number | 20040079038 10/280827 |
Document ID | / |
Family ID | 32107028 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040079038 |
Kind Code |
A1 |
Crooker, Robert H. JR. |
April 29, 2004 |
Curtain wall anchor
Abstract
The panels and mullions of a curtain wall are attached to the
frame of the building enclosed by the curtain wall with anchors
which permit the frame to shift horizontally and vertically
relative to the curtain wall so that the frame and the curtain wall
can experience different degrees of racking. Each anchor includes a
base member and a displaceable member located in front of the base
member. Both members have keyways and are coupled together with a
horizontal key that engages the members at their keyways, allowing
the displaceable member to shift horizontally relative to the
building frame, but preventing it from pulling away from the base
member. Each anchor also has a mullion clamp which is attached
firmly to one of the mullions. It has a vertical keyway where it is
engaged by a key on the displaceable member, thus permitting
vertical displacement of the mullion relative to the building
frame.
Inventors: |
Crooker, Robert H. JR.;
(Murrieta, CA) |
Correspondence
Address: |
POLSTER, LIEDER, WOODRUFF & LUCCHESI
12412 POWERSCOURT DRIVE SUITE 200
ST. LOUIS
MO
63131-3615
US
|
Family ID: |
32107028 |
Appl. No.: |
10/280827 |
Filed: |
October 25, 2002 |
Current U.S.
Class: |
52/235 ;
52/489.1 |
Current CPC
Class: |
E04B 2/96 20130101 |
Class at
Publication: |
052/235 ;
052/733.4; 052/489.1 |
International
Class: |
E04B 002/28 |
Claims
What is claimed is:
1. An anchor for attaching curtain wall panels to the frame of a
building; said anchor comprising: a base member adapted to be
attached to the frame of the building; a displaceable member
located in front of the base member and being coupled to the base
member such that it can shift relative to the base member along a
first axis, yet cannot pull away from the base member, an
attachment member configured to be attached to a component of a
curtain wall and being coupled to the outside member such that it
can shift relative to the outside member along a second axis which
is located at an angle to the first axis, yet cannot pull away from
the displaceable member.
2. An anchor according to claim 1 wherein one of the axes is
horizontal, and the other axis is vertical.
3. An anchor according to claim 1 wherein the first axis is
horizontal and the second axis is vertical.
4. An anchor according to claim 3 wherein the displaceable member
slides relative to the base member along the first axis, and the
attachment member slides relative to the displaceable member along
the second axis.
5. An anchor according to claim 3 wherein one of the base or
displaceable members has a keyway and the other member carries a
key which engages said one member at the keyway such that the other
member can shift along the first axis, but cannot be displaced
laterally with respect to the first axis, whereby the displaceable
member can shift horizontally, but cannot be withdrawn from or
drift toward the base member.
6. An anchor according to claim 5 wherein each of the base and
displaceable members has a keyway, and the key engages both members
at their keyways such that the key can slide in the keyways along
the first axis, but cannot be displaced laterally with respect to
the keyways.
7. An anchor according to claim 5 wherein the attachment member has
a keyway and the displaceable member carries another key which
engages the attachment member at its keyway such that the
attachment member can slide along the second axis but cannot be
displaced laterally with respect to the second axis.
8. An anchor according to claim 7 wherein the attachment member has
spaced apart walls to receive a mullion between them.
9. The anchor of claim 1 in combination with a building having a
frame provided with mounting surface; and wherein the base member
of the anchor is attached securely to the mounting surface on the
frame.
10. In combination with a building having a frame provided with a
mounting surface, a curtain wall comprising: side-by-side panels
located outwardly from the frame; a mullion located between the
side-by-side panels; and an anchor located between the mounting
surface on the building frame and the mullion to position the
panels beyond the frame, the anchor including a base member
attached securely to the frame against the mounting surface, a
displaceable member coupled to the base member such that it can
slide relative to the base member along a first axis but cannot
pull away from the base member, and a mullion clamp attached to the
mullion and coupled to the displaceable member such that it can
slide relative to the displaceable member along the second axis,
but cannot pull away from the displaceable member, one of the axes
being oriented vertically and the other of the axes being oriented
horizontally.
11. The combination according to claim 10 wherein one of the base
or displaceable members has a keyway and the other member carries a
key which engages said one member at the keyway, with the keyway
and key being configured such that the other member can shift
relative to said one member along the first axis but cannot be
displaced laterally with respect to the first axis.
12. The combination according to claim 11 wherein the mullion clamp
has a keyway and the displaceable member carries another key which
engages the mullion clamp at the keyway on the mullion clamp, with
the other key and the keyway of the mullion clamp being configured
such that the mullion clamp can slide relative to the displaceable
member along the second axis, but cannot be displaced laterally
with respect to the second axis.
13. The combination according to claim 10 wherein both the base and
displaceable members have keyways and the key engages both members
at their keyways, with the keyways and key being configured such
that the displaceable member can slide relative to the base member,
but cannot be displaced laterally with respect to the first
axis.
14. The combination according to claim 13 wherein the mullion clamp
has a keyway and the displaceable member carries another key which
engages the mullion clamp at the keyway on the mullion clamp, with
the other key and the keyway of the mullion clamp being configured
such that the mullion clamp can slide relative to the displaceable
member along the second axis, but cannot be displaced laterally
with respect to the second axis.
15. The combination according to claim 10 wherein one of the axes
is horizontal and the other axis is vertical.
16. The combination according to claim 10 wherein the first axis is
horizontal and the second axis is vertical.
17. In combination with a building having a frame provided with a
mounting surface, a curtain wall comprising: side-by-side panels
located outwardly from the frame; a mullion located between the
side-by-side panels, and an anchor located between the mounting
surface on the building frame and the mullion to position the
panels beyond the frame, the anchor including a base attached to
the building frame at the mounting surface on the frame, a
displaceable member located in front of the base member, one of the
base or displaceable members having a keyway and the other member
carrying a key which engages said one member at the keyway, with
the keyway and key being configured such that the other member can
shift horizontally relative to said one member along a horizontal
axis but cannot be displaced laterally from the axis, the
displaceable member also being connected to one of the
mullions.
18. The combination according to claim 17 wherein both the base and
displaceable members have a keyway and the key engages both members
at their keyways, with the keyways and key being configured such
that the displaceable member can slide relative to the base member,
but cannot be displaced laterally from the axis.
Description
CROSS REFERANCE TO RELATED APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] This invention relates in general to building cladding
materials, such as curtain walls, and more particularly to anchors
for curtain walls.
[0004] Many buildings of current construction, particularly
commercial buildings, derive no structural support from their
exterior walls. These walls simply isolate the interiors of the
buildings from the environment outside the buildings and as such
are called "curtain walls". The typical curtain wall comprises a
multitude of panels arranged side-by-side and in tiers, and
mullions separating the side-by-side panels. Indeed, the panels are
attached to the mullions with fastening devices which may assume a
variety of configurations. To a measure the configuration of a
fastening device depends on the nature of the panel that it
fastens, and the panels may be formed glass, metal, or even stone,
such as granite, and in some cases cast concrete. In addition, the
typical curtain wall has anchors which secure the mullions to
structural components of the building, whether they be steel
girders or columns or cast concrete decks or columns, which
components form the frame of building.
[0005] Modern building codes require a measure of flexibility in
buildings, and this holds particularly true for the codes in
seismic zones such as California. These buildings must be capable
of undergoing a swaying motion, called "racking", of as much as 5
inches from floor to floor. In many buildings the frame can
withstand more racking than the curtain wall which encloses it, and
this holds particularly true for building having glazed curtain
walls. Indeed, it is not unusual for the frame to rack as much as
three or more inches from floor to floor, while the curtain wall
has the capacity to rack only one inch from floor to floor. Thus,
when the frame shifts, as for example during a seismic event, the
curtain wall moves with it until the curtain wall can rack no more.
At this point, the continued racking of the frame will damage the
curtain wall. The problem is particularly acute for buildings
having glazed curtain walls. Building codes require that the glass
in such curtain walls remain in place and not crack during
racking.
[0006] To be sure, anchors exist for attaching the mullions and
panels of a curtain wall to the frame of a building while
accommodating differential racking between the frame and the
curtain wall, but these anchors tolerate only small differences in
racking.
[0007] The typical anchor relies on slotted bolt holes and bolts
loosely fitted through such holes to accommodate displacement
between the mullions and the building frame. Aside from tolerating
only a limited differential in the racking, the bolts tend to bind
in the slotted holes, and when this occurs the anchors tolerate
even less differential racking. Moreover, the anchors are usually
custom designed and fabricated specifically for the buildings on
which they are installed.
SUMMARY OF THE INVENTION
[0008] The present invention resides in a curtain wall anchor that
includes a base member adapted to be attached to the frame of a
building, a displaceable member coupled to the base member such
that it can shift along a first axis relative to the base member,
and an attachment member coupled to the displaceable member such
that it can shift along a second axis relative to the displaceable
member. The invention also resides in the anchor mounted on a
building frame at its base member and coupled to curtain wall
components at its attachment member. The invention further resides
in an anchor having a base member mounted on a building frame and a
displaceable member coupled to the base member through a key and
keyway such that the displaceable member can shift horizontally
relative to the base member, and wherein the displaceable member is
coupled to a mullion in a curtain wall.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0009] FIG. 1 is a fragmentary elevational of a building provided
with a curtain wall attached to the frame of the building with
anchors constructed in accordance with an embodying the present
invention, with the curtain wall being broken away to show the
frame of the building;
[0010] FIG. 2 is a fragmentary sectional view of a building
provided with a curtain wall attached with anchors constructed in
accordance with an embodying the present invention;
[0011] FIG. 3 is a plan view of an anchor taken along line 3-3 of
FIG. 2;
[0012] FIG. 4 is a sectional view of the anchor taken along line
4-4 of FIG. 3;
[0013] FIG. 5 is a perspective view of the anchor attached to a
mullion; and
[0014] FIG. 6 is a fragmentary perspective view of the anchor
showing its back face.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Referring now to the drawings, a building has a structural
frame A (FIGS. 1 & 2) and a cladding system, called a curtain
wall B, which encloses the frame A to isolate the interior of the
building. Typically, the building has multiple stories, and the
frame A extends through all of the stories. During seismic events,
the frame A will move or rack in the sense that its upper regions
will displace horizontally relative to its lower regions. The
side-to-side displacement could amount to as much as 2% of the
vertical height of the frame A. The curtain wall B follows this
movement and undergoes racking itself, but its capacity to rack is
not as great as that of the frame A.
[0016] Structural steel better withstands flexures that poured
concrete, so preferably the frame A, where seismic events are
expected, is fabricated from structural steel. The frame A includes
(FIGS. 1 & 2) steel columns 2 and girders 4 spanning the spaces
between the columns 2. It also has brackets 6 which are welded to
the columns 2 and girders 4 to provide vertical mounting surfaces
to which the curtain wall B is attached. Even so, the curtain wall
B is well-suited for use on frames of other construction, such as
poured concrete. Such frames likewise have columns and also have
decks supported by the columns. Both can be fitted with the
brackets 6 or otherwise provided with vertical surfaces for
attachment of the curtain wall B.
[0017] The curtain wall B includes (FIG. 1) panels 12, which
actually enclose the sides of the exterior of the building, and
mullions 14 which extend vertically between adjacent panels 12. The
panels 12 may be glass or formed from a sheet metal such as
aluminum. They may also be slabs of stone, such as granite, or even
a thin slabs of cast concrete. Whatever, their composition, they
are attached to the mullions 14 which hold them in place, there
being a variety of fastening devices available for making the
attachments. The mullions 14 are standard and are typically
aluminum extensions of tubular configuration. Each has (FIGS. 3
& 5) a flat back wall 16, flat parallel side walls 18, and a
front wall 20 configured to cooperate with the fastening devices
that secures the panels to the mullions 14. Being formed from
aluminum, the mullions 14 expand and contract at a greater rate
than the steel columns 2 and girders 4 which lie behind them. In
other words, the coefficients of thermal expansion differ.
[0018] Finally, the curtain wall B includes (FIGS. 1 & 2)
anchors 26 and 28 which hold the mullions 14 along the frame B and,
of course, the panels 12 as well since the panels 12 are attached
to the mullions 14. The anchors 26 actually provide support for the
mullions 14 and the array of panels 12 attached to them and are
known as "dead load anchors". While they can accommodate horizontal
displacement between the mullions 14 and the frame A, they do not
permit vertical displacement. As such the anchors 26 are located at
the lower ends of the mullions 14. In this regard, a succession of
mullions 14 may align along the frame A and give the appearance of
a single mullion, but each mullion 14 in the succession, at its
lower end, is attached to the frame A with a dead load anchor 26.
The remaining anchors 28, which are sometimes referred to as "wind
load anchors", attach the mullions 14 to the frame A above the dead
load anchors 26, that is to say, for each mullion 14, a dead load
anchor 26 secures that mullion 14 to the frame A at its lower end
and one, or more likely more, wind load anchors 28 secure the
mullion to the frame A elsewhere. They accommodate both horizontal
and vertical displacement between the mullions 14 and the frame A
and in that sense are universal anchors. Moreover, as their name
implies, the transfer wind loads to the frame A.
[0019] Each wind load anchor 28 includes (FIGS. 3-5) a base member
32 which is attached, preferably by bolts 30 to one of the brackets
6 on the frame A of the building where it extends horizontally, it
being about 6 to 8 inches long. The base member 32, has a web 34
and stiffening flanges 36 along the upper and lower margins of the
web 34. Between the flanges 36 the base member 32 has a pair of
rails 38, each of which projects outwardly from the exposed face of
the web 34 and then turns vertically in the provision of a
retaining flange 40. Indeed, the flanges 40 from the two rails 38
project toward each other, but do not meet, there being a
horizontally directed gap between the two retaining flanges 40. The
rails 38 together with the region of the web 34 that lies between
them forms a keyway 42 that opens away from the frame A and
establishes a horizontal axis X1. The bolts 30 pass through the
regions of the web 34 between the stiffening flange 36 and the
rails 38 and also through the bracket 6, and are secured with
nuts.
[0020] The anchor 28 also includes a displaceable member 44 which
possess the same cross-sectional configuration as the base member
32 and therefore has a web 34, stiffening flanges 36, rails 38,
including retaining flanges 40, and a keyway 42. It too is an
aluminum extrusion, typically 6 to 8 inches long, but may be
longer, inasmuch as the length can vary by applications. Indeed, it
may be extruded from the same die as the base member 32.
[0021] The base and displaceable members 32 and 44 are coupled by a
horizontal key 50 (FIGS. 4 & 5) which is likewise preferably an
aluminum extrusion. It prevents the members 32 and 44 from
separating, yet allows the displaceable member 44 to shift
horizontally with respect to the base member 32 along the axis X1.
The key 50 possess an H-shaped cross section, it having a
connecting segment 52 and flanges 54 projecting both upwardly and
downwardly at both sides of the connecting segment 52. The flanges
54 on the key 50 fit into the keyway 42 of the base and
displaceable members 32 and 44 where they lie behind the retaining
flanges 40 on the rails 38. The connecting segment 52 fits into the
spaces between the opposed retaining flanges 40 of the rails 38 and
spans the space between the rails 38 on the base member 32 and the
rails 38 on the displaceable member 44. The key 50, in effect,
engages the two members 32 and 44 at their keyways 42 such that the
members 32 and 44 cannot be separated, yet the displaceable member
44 can shift relative to the base member 32 along the horizontal
axis X1. The sides of the key 50 lie close to, if not against, the
webs 34 on the two members 32 and 44, so the key 50 prevents the
members 32 and 44 from approaching as well. Nevertheless, the key
50 fits somewhat loosely into the keyways 42 on the two members 32
and 44, so that the key 50 may slide easily in the keyways 42. This
permits the displaceable member 44 to shift horizontally in either
direction along the axis X1 over the base member 32. To prevent the
key 42 from leaving keyway 42 of the base member 32, the base
member 32 in its web 34, between the two rails 38, contains (FIG.
6) a slot 56, the longitudinal axis of which lies parallel to the
axis X1. The key 50, on the other hand, is fitted with a pin 58
which projects from it into the slot 56. Thus, the pin 58 confines
the displacement of the key 50 in the keyway 42 of the base member
32 to essentially the length of the slot 56. The displaceable
member 44 may of course shift still farther on the key 50.
[0022] In addition to the base and displaceable members 32 and 44,
and the horizontal key 50 that is between them, the wind load
anchor 28 has a vertical key 64 which is fastened firmly to the
displaceable member 44. The vertical key 64 includes a center
segment 66 and two flanges 68 at the outer end of the center
segment 66 where they project laterally from the center segment 66,
giving the vertical key 64 a T-shaped cross-sectional
configuration. The vertical key 64 is attached to the displaceable
member 44 at the inner end of its center segment 66 where it is
secured against the web 34 of the member 44, preferably with cap
screws 70 which pass through the web 66 above and below its rails
38 and thread into the center segment 66. The vertical key 64, like
the horizontal key 50, may be an aluminum extension.
[0023] Lastly, the anchor 28 includes a mullion clamp 76 that is
fitted to the vertical key 64 and receives the mullion 14 to which
it is firmly fastened. As such, the mullion clamp 76 serves as the
attachment member for the anchor 28. It too may be an aluminum
extrusion. More specifically, the mullion clamp 76 includes
parallel side walls 78 which are spaced far enough apart to receive
the mullion 14 loosely between them, with the side walls 18 of the
mullion 14 lying along the inside surfaces of the side walls 78 on
the clamp 76. The side walls 78 of the clamp 76 terminate short of
the front wall 20 on the mullion 14, so that they do not interfere
with the panels 12. The two side walls 78 are connected by a cross
wall 80 (FIG. 3) from which vertical rails 82 project rearwardly.
Each rail 82 terminates at an inwardly directed retaining flange
84. The spacing between the opposed flanges 84 slightly exceeds the
width of the center section 66 on the vertical key 64, whereas the
spacing between the flanges 84 and the cross wall 80 slightly
exceeds the thickness of the flanges 84. In other words, the
vertical rails 82 together with the cross wall 80 creates, on the
back of the mullion clamp 76, a keyway 86 having a vertical axis
X2, and that keyway 86 receives the vertical key 64 that is
attached to the displaceable member 44. Indeed, the key 64 fits
loosely enough in the keyway 86 to enable the mullion clamp 76 to
slide upwardly and downwardly on the key 64 without pulling away
from the outer member 44. The mullion clamp 76 is secured firmly to
the mullion 14 with machine bolts 88 which pass through the side
walls 78 of the clamp 76 as well as through the side walls 18 of
the mullion 14.
[0024] The wind load anchor 28 may be easily converted into a dead
load anchor 26 simply by securing the mullion clamp 76 to the
vertical key 64, such as by extending the cap screws 70 into the
cross wall 80 of the mullion clamp 76. This prevents the mullion 14
from shifting vertically with respect to the anchor 28 and frame
A.
[0025] The wind load anchors 28 accommodate both vertical and
horizontal displacement of the section of the mullion 14 that lies
in front of the bracket 6 to which the anchor 28 is fastened.
Should the frame A of the building rack, perhaps as the result of a
seismic event, the bracket 6 for a wind load anchor 28 will undergo
a horizontal displacement and perhaps a slight vertical
displacement as well. The curtain wall B, may follow the frame A
and undergo racking as well, but not to the extent that the frame A
experiences, particularly if some of the panels 12 in the curtain
wall are glazed. The anchors 28, accommodate the difference in the
amount of rack experienced by the frame A and the curtain wall B,
allowing the frame A to, in effect, undergo displacement behind the
curtain wall B.
[0026] In this regard, as the bracket 6 on which an anchor 28 is
mounted shifts horizontally the base member 32 of the anchor 28
moves with it. However, the displaceable member 44 remains in the
same lateral position as the mullion 16 which the anchor 28 secures
and the mullion 16 remains essentially with the panels 12 on either
side of it, and while the curtain wall B may and probably does move
horizontally, it displaces a lesser amount. In short, the base
member 32 moves horizontally behind the displaceable member 44
which is displaceable in the sense that it moves relative to the
base member 32. More specifically, the horizontal key 50 slides in
the keyway 42 of the base member 32 or the keyway 42 of the
displaceable member 44 or in both keyways 42, thereby accommodating
the horizontal displacement. The horizontal displacement caused by
the racking could be accompanied by a vertical displacement of the
frame bracket 6 relative to the portion of the mullion 16 that lies
behind it. In that event the vertical key 64 moves vertically in
the keyway 86 of the mullion clamp 76. The vertical keyway 86 also
accommodates vertical displacement of the mullion 14 caused by
differential thermal expansion. Notwithstanding the freedom to
shift both horizontally and vertically relative to the frame A, the
mullion 14 cannot pull away from or move toward the building frame
A. It remains in place in this respect.
[0027] Variations are possible. For example, only one keyway 42
will accommodate horizontal displacement, so the horizontal key 50
may be fixed firmly to or extruded integral with either the base
member 32 or the displaceable member 44. Also, the vertical key 64
may be on the mullion clamp 76 and the vertical keyway 86 on the
web 34 of the displaceable member 44. Moreover, the key 50 and
keyways 42 can be oriented vertically to accommodate the vertical
displacement, while the key 64 and keyway 86 can be oriented
horizontally to accommodate horizontal displacement. Furthermore,
the mounting surfaces to which the anchors 26 and 28 are attached
need not be on brackets 6 and need not be oriented vertically.
* * * * *