U.S. patent application number 12/580932 was filed with the patent office on 2010-08-05 for load sensitive snow barrier device.
This patent application is currently assigned to Roofers World Inc.. Invention is credited to Craig Elliott, Cam Haszczyn, Robin Nelson, Gabrielle Pell, Han Yao.
Application Number | 20100192479 12/580932 |
Document ID | / |
Family ID | 42371438 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100192479 |
Kind Code |
A1 |
Elliott; Craig ; et
al. |
August 5, 2010 |
LOAD SENSITIVE SNOW BARRIER DEVICE
Abstract
A snow-retaining device comprises a detachable upper member
attached to a base anchor. The base anchor is adapted to be coupled
to a roof. The upper member prevents snow from sliding off the roof
during regular snow conditions. In order to prevent catastrophic
damage to the roof, if a snow load on the roof exceeds a maximum
threshold, the upper member detaches from the base anchor to allow
some or all of the snow to slide off the roof. The device
optionally integrates a snow melting device.
Inventors: |
Elliott; Craig; (Ottawa,
CA) ; Pell; Gabrielle; (Ottawa, CA) ;
Haszczyn; Cam; (Ottawa, CA) ; Nelson; Robin;
(Ottawa, CA) ; Yao; Han; (Ottawa, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET, FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Assignee: |
Roofers World Inc.
Ottawa
CA
|
Family ID: |
42371438 |
Appl. No.: |
12/580932 |
Filed: |
October 16, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61148903 |
Jan 30, 2009 |
|
|
|
Current U.S.
Class: |
52/24 ;
52/741.3 |
Current CPC
Class: |
E04D 13/106 20130101;
E04D 13/103 20130101 |
Class at
Publication: |
52/24 ;
52/741.3 |
International
Class: |
E04B 1/92 20060101
E04B001/92; E04D 13/10 20060101 E04D013/10 |
Claims
1. A snow-retaining device comprising a detachable upper member
attached to a base anchor, said base anchor adapted to be coupled
to a roof; wherein: a. said upper member remains attached to said
base anchor when snow having a given load accumulates on said roof;
and b. said upper member detaches from said base anchor when snow
having more than said given load accumulates on said roof.
2. The snow-retaining device of claim 1, wherein said upper member
is flexibly attached to said base anchor.
3. The snow-retaining device of claim 2, wherein a spring-load
means is used to flexibly attach said upper member to said base
anchor.
4. The snow-retaining device of claim 2, wherein said upper member
comprises a fold-away means.
5. The snow-retaining device of claim 1, wherein said upper member
is removably attached to said base anchor and detaches from said
base anchor when said given load is attained.
6. The snow-retaining device of claim 1, wherein said base anchor
is coupled to said roof using adhesive or mechanical means.
7. The snow-retaining device of claim 1, further comprising a means
for melting said snow and ice.
8. The snow-retaining device of claim 1, wherein said given load is
750 lbs.
9. The snow-retaining device of claim 1, wherein said upper member
and base anchor comprise polycarbonate.
10. The snow-retaining device of claim 1, wherein said upper member
has a flat surface.
11. The snow-retaining device of claim 10, wherein said flat
surface has a shape of a polygon, circle, or an area defined by a
combination of lines and curves.
12. A method of protecting a roof from damage due to excessive snow
accumulation, said method comprising placing a plurality of
snow-retaining devices on said roof; said snow-retaining device
comprising an upper member attached to a base anchor, wherein said
base anchor attaches to said roof; said upper member retains snow
accumulated on said roof until a maximum allowable snow load for
said upper members is attained.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/148,903 filed on Jan. 30, 2009 which is
hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to snow barriers or
guards that are coupled to a roof to inhibit the sliding of
accumulated snow from the roof up to a pre-determined load, thereby
preventing damage to the roof due to excessive accumulation of
snow.
BACKGROUND
[0003] It is well known in the art to apply brackets, stops, or
fences to a roof in order to prevent snow that has accumulated upon
the roof from sliding from the roof. These devices help to keep
snow from damaging eavestroughs, landscaping on the ground below,
etc., or falling dangerously onto pedestrians or vehicles.
Nonetheless, the devices serve to maintain snow loads on the roof
itself, thereby contributing to the roof caving in or causing undue
stress to the roof when the snow load is excessive.
[0004] There have been some attempts to address the problem of
excessive snow load accumulation in the prior art.
[0005] U.S. Pat. No. 5,522,185 to Cline discloses a snow stop for
attachment to a metal roof seam, comprising a flat, rigid blade
formed with curved upper and lower edges. There are openings
extending through the blade that permit the passage of air and
fluids, and in particular, water. The device described in Cline is
restricted to seams of metal roofs. In addition, the openings of
the flat blade are not designed to allow for the flow of solids
such as snow or ice. Consequently, the snow stop cannot effectively
reduce the snow load on a roof in order to prevent a roof from
caving in.
[0006] U.S. Pat. No. 6,357,184 to Alley discloses a device capable
of being attached to a roof as part of a snow guard system to
better restrain snow or ice from falling off the roof. The device
includes flags attached to pipes that run longitudinally along the
edge of the roof. The flags are designed not to rotate, and extend
below the bottom-most pipe in order to restrain snow from sliding
off a roof. Alley further discloses prior art devices comprising
flags attached to pipes, wherein the bottom of the flags is spaced
from the roof. In addition, these prior art flags are secured to
the pipes using screws, thereby providing essentially a grid-like
snow stop at the edge of the roof. According to Alley, such a prior
art device allows a portion of the snow load to fall from the roof,
thereby preventing snow from accumulating to dangerous levels.
However, there are a number of drawbacks generally associated with
these snow guards. In particular, the securing means to attach
flags to the pipes do not entirely prevent rotation of the flags
when subjected to disturbances such as wind gusts. In addition, the
securing means are expensive to manufacture and difficult to
install. Furthermore, while the device may haphazardly permit a
small portion of the snow load to fall from the roof, it is not
designed to fail under the weight of dangerous snow load.
[0007] U.S. Pat. No. 6,536,166 also to Alley discloses a snow guard
assembly adapted to be attached to a metal roof seam by a mounting
assembly. The mounting assembly includes a mounting block having a
seam-receiving groove formed in its bottom surface, and at least
one coupling element, which can function as a shear pin, extending
through a first side portion of the mounting block. This coupling
element provides the snow guard assembly with a break-away feature,
wherein the second member of the coupling element is enabled to
shear at a predetermined location under a force exceeding a
predetermined threshold force to release the entire snow guard
assembly from the metal roof seam. The break-away feature is meant
to prevent portions of the metal roof itself from lifting and
loosening under the weight and force from an excessive snow load on
the snow guard attached thereto. The material selection is an
important consideration when engineering the coupling member as a
shear pin, since some materials are known to shear under more or
less force than others. This device, for use with metal roofs only,
is designed to prevent roof damage at the point of attachment only,
and does not prevent the dangerous accumulation of snow on the
entire metal roof.
[0008] U.S. Patent Publication No. 2007/0245636 to Ayer et al.
discloses a snow guard for roofs that comprises a plurality of
slotted brackets, which are permanently installed atop the roof. A
snow fence is removably installed in the slots of the brackets,
permitting the user to remove the fence as needed for the
deliberate removal of snow from the roof in a safe and
predetermined manner. This device requires the user to monitor the
snow accumulation and manually remove the device before a
significant snow load should threaten damage to the roof.
[0009] None of the cited prior art disclose a snow barrier having a
load sensitive mechanism to prevent large snow deposits from
damaging roofs or even causing them to cave in.
[0010] There is a need for a snow guard or barrier device that
prevents snow from sliding off a roof in regular or normal snow
conditions, yet automatically collapses once a given snow load
threshold is reached in order to prevent catastrophic damage to the
roof. The device should not require cumbersome reattachment of the
entire device to the roof.
SUMMARY OF THE INVENTION
[0011] The present invention keeps snow from sliding off a roof
during regular snow conditions, while allowing excessive snow to
safely slide off once a given snow load threshold is reached in
order to prevent catastrophic damage to the roof.
[0012] In one aspect of the present invention, there is provided a
snow-retaining device or barrier comprising an upper member
attached to a base anchor which is coupled to a roof. The upper
member retains snow accumulated on the roof during regular snow
conditions. Once an allowable snow load against the upper member is
attained, the upper member collapses to allow some or all of the
snow to slide off the roof. The maximum allowable snow load against
the upper member may be set to, for example, 750 lb, although this
threshold may vary in accordance with the location and expected
snow conditions.
[0013] The device is designed to allow the upper member to be
flexibly attached to the base anchor, preferably by a spring-load
means; or the upper member may comprise a fold-away means.
[0014] Alternatively, the upper member can be removably attached to
the base anchor and detaches from the base anchor when the maximum
allowable snow load is attained.
[0015] The base anchor is attached to the roof using adhesive or
mechanical means. Furthermore, the snow-retaining device may
comprise a mechanism to assist in melting the snow and ice.
[0016] The upper member and base anchor are comprised of a suitable
material such as polycarbonate. The upper member may be of any
shape, so long as it can function as a snow barrier during normal
snow conditions. In one embodiment, the upper member has a flat
surface that has a shape of a polygon, circle, or an area defined
by a combination of lines and curves. In another embodiment, the
upper member can have a recognizable shape such as an eagle or star
silhouette.
[0017] In another aspect of the present invention, there is
provided a method of protecting a roof from damage due to excessive
snow accumulation, comprising placing a plurality of the
snow-retaining devices described herein on the roof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIGS. 1(a) and 1(b) illustrate first and second perspective
views, respectively, of a snow barrier device of one embodiment of
the present invention.
[0019] FIG. 2 illustrates a perspective view of another embodiment
of the present invention.
[0020] FIG. 3 illustrates a rear view of an upper member of another
embodiment of the present invention.
[0021] FIG. 4 illustrates the upper member of FIG. 3 in relation to
a base member of the snow barrier of one embodiment of the present
invention, prior to assembly.
[0022] FIG. 5(a) illustrates a side view of the assembled snow
barrier of FIG. 4.
[0023] FIG. 5(b) illustrates a perspective side view of the
partially-assembled snow barrier of FIG. 4.
[0024] FIG. 6 illustrates a perspective view of another embodiment
of the present invention attached to a roof, along with the
integration of a heating cable.
[0025] FIG. 7 illustrates a side view of another embodiment of the
present invention that folds back under an excessive snow load.
[0026] FIG. 8 illustrates examples of shapes of the flat face of
the upper member of the snow barrier of the present invention.
DETAILED DESCRIPTION
[0027] General features of the present invention are shown in FIGS.
1(a) and 1(b). The base anchor (10), which may be made of a
polycarbonate material, is attached to a roof using bolts or screws
that are inserted through holes (20) and (25). Base anchor (10)
optionally includes a base surface (45) that serves as a waterproof
seal. The upper member (30) is removably attached to the base
anchor (10) at an attachment assembly junction (35). The upper
member (30) may also be made of polycarbonate material.
[0028] As illustrated, upper member (30) preferably has a generally
flat face (32), that may be of any shape. The illustrated shape is
generally octagonal. Other contemplated geometrical shapes for the
flat face (32) of upper member (30) are depicted in FIG. 8. Further
shapes for the flat face (32) of upper member (30) are contemplated
(not shown), and include shapes with or without holes, screens and
other barrier shapes. Such shapes may also be of recognizable
silhouettes including an eagle, star or other known shape.
[0029] The base anchor (10) can be mounted to the roof using
adhesive, mechanical or other known coupling means. When mounted,
in normal operating conditions, upper member (30) is about
perpendicular to base anchor (10).
[0030] The device of the present invention may be installed on
roofs where the average snow accumulation per year is known.
[0031] When there is heavy snow accumulation on the roof, once the
horizontal load against upper member (30) exceeds a certain
threshold, the upper member (30) fails, such as by detaching from
anchor base (10), thereby allowing for some or all of the snow in
proximity to the device to slide off the roof. By failing at the
given threshold, the device fails as a snow barrier but succeeds in
preventing the dangerous load of snow from causing damage to the
roof by allowing a path to fall off the roof. Conditional failure
of upper member (30) is therefore a safety mechanism.
[0032] A device with a failed upper member (30) may be repaired or
replaced on the same base member (10), typically after the
dangerous accumulation of snow is no longer present. If repaired,
the broken-away upper member (30) may be used if it was not damaged
during the failure. Alternatively, a new upper member (30) may be
coupled to the base member (10). While upper member (30) must be
attached subsequent to failure in order to continue using the
device, the base anchor (10) of the present invention remains
coupled to the roof, and does not need to be re-anchored.
[0033] In another embodiment, upper member (30) is flexibly
attached to the base anchor by using, for example, a spring-load
mechanism. Once the snow load reaches a certain threshold, upper
member (30) fails by receding or falling back, thereby allowing
some or all of the snow to slide off the roof. Once the excessive
snow has fallen, the upper member (30) may be biased back to its
original operating position, typically about perpendicular to base
anchor (10). Alternatively, after the excessive snow has fallen,
upper member (30) may be manually adjusted to its operating
position.
[0034] The base anchor (10) assembly also functions as a lesser
snow brake in the event snow loads exceed a certain threshold per
anchor, which can be set as the same threshold required for the
upper member (30) to give way.
[0035] Whether the upper member (30) is attached flexibly or
removably to the base anchor (10), an optional means for melting
the snow, such as a heating cable, can be integrated into the snow
barrier of the present invention, such as at groove (40) in base
anchor (10).
[0036] FIG. 2 illustrates an example of a snow barrier of the
present invention designed to operate without an optional means for
melting the snow. Upper member (42) is attached to base anchor (44)
at assembly junction (46), while base anchor (44) comprises a hole
(48) for attaching the snow barrier to a roof by use of a screw or
other equivalent fastening means. Unlike the base anchor (10) of
FIGS. 1(a) and (b), base anchor (44) of FIG. 2 does not incorporate
a groove for incorporation of a heating element.
[0037] An example of a snow barrier with a detachable upper member
is shown in FIGS. 3-6. FIG. 3 illustrates the attachment features
of an upper member (50) of another embodiment of the present
invention. These attachment features, used to attach the upper
member (50) to the base anchor (80) (shown in FIG. 4), include
snap-in-place lugs (55) and (56), and side/twist load lugs (60) and
(61). The accompanying base anchor (80) of FIG. 4 includes an
attachment assembly junction (105), to which a portion of the upper
member (50) attaches as follows: snap-in-place lug (55) fits into
mating slot (90), snap-in-place lug (56) fits into a mating slots
(91), and side/twist load lugs (60) and (61) fit into mating slot
(95). In addition, base anchor (80) includes: a groove (85) for an
optional heating cable; holes (110) and (111) for bolts/screws for
the attachment of the base anchor to the roof; and a base (75) for
a waterproof seal of the base anchor (80). Alternatively, an
adhesive can be applied to the underside of base (75) in order to
secure the base anchor (80) to the roof. The base anchor (80) and
upper member (50) are preferably each made of polycarbonate
material.
[0038] The upper member (50) and base anchor (80) of FIGS. (3) and
(4) are shown assembled together in FIG. 5(a) and partially
assembled in FIG. 5(b). In particular, the perspective view of FIG.
5(b) illustrates the fitting of snap-in-place lugs (55) and (56),
and side/twist load lugs (60) and (61) and into their respective
mating slots. In addition, both means for attaching the base anchor
(80) to the roof are shown in FIG. 5(b): holes (110) and (111) for
bolts or screws, and base (75) for application of an adhesive.
[0039] FIG. 6 shows another embodiment of the invention comprising
upper member (50) and base anchor (80) attached to a roof (130) via
screw (140) (another screw on the other side of the base anchor
(80) is not shown). In addition, a heating cable (120) passes
through a groove (85) on the underside of the base anchor (80).
[0040] In this embodiment, upper member (50) breaks off when the
snow load on the face of the upper member exceeds a certain
threshold. In this instance, side/twist load lugs (60) and (61)
detach from mating slot (95), and snap-in-place lugs (55) and (56)
detach from mating slots (90) and (91) respectively. Once detached,
the upper member (50) can be recovered and attached once again to
the base anchor (80) as described above.
[0041] An example of a snow barrier with an upper member (150) that
is flexibly attached to the base anchor (160) is shown in FIG. 7.
The base anchor (160) includes a groove (170) for optional
inclusion of a heating cable, and an attachment junction (180)
where upper member (150) is attached to the base anchor (160). The
upper member (150) includes a notch (200) that extends across the
face (190); the notch (200) acts as a failure mechanism allowing a
portion of the upper member to fail or fold back when the snow load
against the face (190) of upper member (150) exceeds a certain
threshold, thereby allowing some or all of the snow to slide off
the roof. Once the excessive snow has fallen, the upper member
(150) may be replaced or manually adjusted to its operating
position.
[0042] Depending on the embodiment illustrated, grooves (40, 85,
170) allow a heating cable to be integrated with the snow barrier.
For example FIG. 6 illustrates the snow barrier fixed to roof (130)
wherein heating cable (120) is integrated in groove (85). Together,
the heating cable (120) and snow barrier perform the dual task of
melting snow and ice deposits on the roof and keeping snow from
sliding off the roof.
[0043] For roofs that presently incorporate a heating cable, the
device of the present invention can be fixed at a plurality of
locations on the heating cable. Alternatively, a heating cable and
one or more snow barriers may be attached to a roof.
[0044] A plurality of snow barrier devices of the present invention
may be placed at various intervals along one or more sides of a
roof. The number of devices and the spatial distance between each
device depends on various factors including where the building is
located, the average annual snow accumulation in the area, the snow
dump area on failure, the size/slope/material composition of the
roof, presence of eave troughs or other roofing accessories,
etc.
* * * * *