U.S. patent number 3,677,576 [Application Number 05/061,099] was granted by the patent office on 1972-07-18 for roof flange with elastomeric collar.
Invention is credited to Craig S. Gustafson.
United States Patent |
3,677,576 |
Gustafson |
July 18, 1972 |
ROOF FLANGE WITH ELASTOMERIC COLLAR
Abstract
Roof flanges with elastomeric collars having improved sealing
characteristics. With the collar belling gradually from its
opening, defining a convex surface engaging the pipe over a
substantial distance, a liquid-tight seal results despite
variations in the size or surface of the pipe. A pre-applied
lubricant on the sealing surface enables attachment of high
pressure collars while improving sealing.
Inventors: |
Gustafson; Craig S. (Lincoln,
MA) |
Family
ID: |
22033579 |
Appl.
No.: |
05/061,099 |
Filed: |
August 5, 1970 |
Current U.S.
Class: |
285/43;
285/423 |
Current CPC
Class: |
E04D
13/1471 (20130101) |
Current International
Class: |
E04D
13/147 (20060101); E04D 13/14 (20060101); E04d
013/00 () |
Field of
Search: |
;285/42,43 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Williamowsky; David J.
Assistant Examiner: Shedd; Wayne L.
Claims
What is claimed is:
1. In a roof flange unit comprising a flange base for sealing with
a roof and a resilient elastomeric collar having a longitudinal
axis and an end opening therein, for gripping and sealing to the
periphery of a pipe of given standard size extending through the
roof, the unit adapted to be applied as one piece over the pipe,
the improvement wherein said elastomeric collar, in the region to
be engaged upon the pipe, comprises a wall of generally bell-shaped
cross-section in radial planes through said axis, said wall
commencing substantially at the opening of said collar, said
opening being substantially smaller than the outer diameter of said
pipe, the wall of said collar, in unstressed condition, belling
outwardly and axially away from said opening exposing an inner
convex smooth sealing surface to said pipe, the tangent to the
sealing surface of said collar in a plane parallel to said axis in
the immediate vicinity of said opening forming an acute angle
relative to said axis, and tangents to points on said surface
further from said opening forming increasingly larger such angles,
whereby upon application of said collar to said pipe, said collar
is radially deformed and resilient hoop stresses are developed in
the collar about the pipe, the resilient deformation commencing at
the collar opening and decreasing only gradually axially along said
wall for a distance on the order of one half inch.
2. The roof flange unit of claim 1 wherein said wall has a total
effective sealing length, beginning at said opening, in the range
of about one inch, the angle of said wall relative to a plane
radial to said axis of said collar varying gradually from
substantially 90.degree. at said opening to less than 45.degree. at
a point most remote from said opening.
3. The roof flange of claim 2 wherein said bell-shaped wall is
integrally joined at its point most remote from said opening with a
resilient attachment bead of substantially greater thickness than
said wall, said collar comprising neoprene rubber, and a metal
flange member permanently crimped about said resilient attachment
bead.
4. The roof flange unit of claim 1 wherein said collar is formed of
neoprene rubber and the wall thickness of said collar at said
opening is on the order of 0.100 inch, the thickness of said wall
decreasing gradually downwardly over a distance on the order of
one-fourth inch.
5. The roof flange unit of claim 1 wherein said collar comprises
neoprene rubber of a wall thickness in the range of between 0.100
inch and 0.050 inch, the diameter of said opening being on the
order of one inch less than the corresponding standard pipe outer
diameter, and a coating of pre-applied water-resistant lubricant
disposed on said convex surface of said collar.
6. The roof flange unit of claim 1 wherein a coating of pre-applied
water-resistant lubricant is disposed on the surface of said collar
adapted to engage said pipe said pre-applied lubricant comprises a
thin coating of silicon lubricant-waterproofing agent.
Description
This invention relates to roof flanges for sealing against rain and
other leakage about pipes that protrude from the roof.
At least since 1957 it has been proposed to employ a roof flange
unit which is applied as one piece, providing a flange for sealing
with the shingles or other composition of a roof and an elastomeric
collar for gripping and sealing to the periphery of a pipe
extending through the roof.
The patent literature, for example, shows Church, U.S. Pat. No.
2,985,465. Since the advent of such units, there has been a
considerable effort, without complete success, of providing such a
roof flange that will accept and completely seal about pipes
varying in size and surface texture. In the patent literature there
are Canadian Pat. 640,736 and U.S. Pat. Nos. 3,098,663 and
3,313,559, to mention a few.
While various such units have been used widely in the field, there
has been a certain frequency of leaks developing about the pipes.
This has been enough to cause many in the construction industry not
to adopt this style of roof flange unit but to continue with other
styles, i.e., metal units having lead or fibrous packing, etc.,
despite the inconvenience as well as possibility of leaks provided
by such other styles.
The principal objects of this invention are to provide an improved
roof flange and in particular a flange which significantly
decreases the likelihood of leaks despite variation in pipe surface
and size.
According to the invention, there is featured an elastomeric collar
in the region to be engaged by the pipe, which comprises a thin
wall of truncated bell shape in unstressed condition. The shape
commences substantially at the opening of the collar and bells
outwardly, downwardly, exposing a convex smooth sealing surface to
the pipe. The unit is adapted to be pressed down over the pipe
until the flange seats on the roof. After application to the pipe,
resilient hoop stresses are developed in the collar about the pipe,
the resilient deformation commencing at the collar opening
decreasing only gradually downwardly along the bell-shaped wall for
a distance on the order of one half inch.
Preferred embodiments of the invention feature: a total bell-shaped
wall length in the range of at least one inch; the angle of the
wall to the radial varying gradually from substantially 90.degree.
at the opening to less than 45.degree. at the most remote point;
the wall joined at its remote point to a thick resilient attachment
bead to which is permanently crimped a metal flange member; and the
wall thickness at the opening decreasing gradually over almost
one-fourth inch from a thickness at the opening on the order of
0.100 inch.
The invention also features a pre-applied coating of
water-resistant lubricant on the substantial convex area of the
collar which is arranged to engage the pipe, preferably featuring a
silicone lubricant waterproofing agent.
These and other objects and features will be understood from the
following detailed description taken in conjunction with the
drawings wherein:
FIG. 1 is a perspective view of a preferred embodiment of the
invention;
FIG. 2 (taken on line 2--2 of FIG. 1) and FIG. 3 are somewhat
diagrammatic cross-sections illustrating different sizes of the
unit of FIG. 1;
FIG. 2a is a cross-sectional view on an enlarged scale of the outer
portion of the collar wall of FIG. 2;
FIG. 4 is a perspective view of the unit in place;
FIG. 5 is a development of the sealing area in diagrammatic form;
and
FIG. 6 is a cross-sectional view illustrating a step in the
manufacture of the unit, FIG. 6a showing the metal port
preassembly.
Referring to FIG. 1, the unit comprises a conventional metal flange
10 and domed portion 12, e.g., an embossure, the latter being
crimped on its upper region about an attachment bead 13 of the
collar 14. As is common, the domed portion sets the axis of the
collar at an angle to the plane of the flange to correspond to the
difference in angle between an average roof pitch and vertical
pipes protruding through the roof.
Referring to FIG. 2, the collar is drawn to scale for use with a
standard 4 inch I.D. pipe (being suitable for both cast iron and
plastic pipes having an O.D. of 4-1/2 inches, with tolerances and
copper pipe having an O.D. of 4-1/8 inches, with tolerances).
The collar, beginning at opening 16 comprises a membrane wall which
bells outwardly downwardly a substantial distance. More
particularly, points A, B, C, D, and E are points along the wall
proceeding at one-fourth inch increments in the direction of the
axis , point A being at the top opening of the collar. In the
unstressed conditions, the points lie at the following diameters
and the angle of the wall at those points relative to the radial
plane of the collar are given in the following table:
TABLE I
Axial Distance Angle .alpha. to Unstressed Point from Opening
Radial Plane I Diameter
__________________________________________________________________________
A 0 80.degree. 3-1/4" B 1/4" 75.degree. 3-3/8" C 1/2" 53.degree.
3-11/16" D 3/4" 32.degree. 4-1/4" E 1" 32.degree. 5-1/4"
__________________________________________________________________________
The collar of the preferred embodiment is of molded neoprene while,
referring to FIG. 2a, the thickness t of the wall at the outer edge
e (at the opening 16) in this preferred embodiment is 0.093 inch
and the wall thickness decreases uniformly to a thickness t.sub.1
of 0.065 inch at a distance d of about one-fourth inch from the
edge e, thereafter the wall being of substantially uniform
thickness.
On the left hand side of FIG. 2 there is shown a vertical line
P.sub.4 representing a standard 4 inch cast iron or plastic pipe
(of O.D. 4-1/2 inches) and line P.sub.4 ' representing a standard 4
inch copper pipe (of O.D. 4-1/8 inches). It is seen (also see FIG.
4) that the wall (in unstressed condition of bell shape) now is
stretched to conform to the pipe surface over a substantial
distance, resiliently applying sealing hoop stresses to the pipe.
The sealing surface of the pipe, convexly bell-shaped and smooth in
unstressed condition now is of cylindrical form in the contact
area. The amount of resilient deformation of the wall decreases
only gradually at a less than linear rate of change downwardly (as
compared to a truncated cone projected through points A and E)
along the wall for a distance of at least one half inch as shown in
the following table and by the arrows in FIG. 5, taking an average
pipe position intermediate P.sub.4 and P.sub.4 ':
TABLE II
% of stressed diameter Unstressed Stressed attributable to Point
I.D. I.D. .DELTA. elastic distension
__________________________________________________________________________
A 3-1/4" 4-1/4" 1" 23-1/2 % B 3-3/8" 4-1/4" 7/8 20-1/2 % C 3-11/16"
4-1/4" 9/16 13-1/2 % D 4-1/4" 4-1/4" 0 0
__________________________________________________________________________
the result is that pipes, of either cast iron, plastic or copper
having the same standard I.D. (despite differences in standard
O.D.) and even, in each case, when at either side of the allowable
tolerances (or even out of tolerance or out of alignment) are all
sealed effectively by the collar when applied. Referring to FIG. 5,
(a development of the gripped area on the pipe), the collar surface
is smooth and grips over a wide area W effectively isolating any
surface discontinuity X, Y or Z and assures that a seal is
perfected about the periphery even in the presence of excrescences
gross depressions and the like (see seal line L and alternate seal
line L.sub.1). In many such cases the collar material need not seal
into the depression, but rather seals entirely around it so that
the depression affords no path for rain leakage from exterior to
interior of the pipe.
As noted from the above tables, significant stretching of the
collar occurs over a large area during placement. Resistance
against tearing of the collar at its outer edge during placement is
provided by the tapered thickness mentioned above.
According to the invention, a lubricant coating 40 shown by dots in
FIg. 1 is pre-applied at the factory to the inner convex, belled
surface from about point A to D. Suitably, an aerosol spray known
as "Marvel" silicone spray is employed, sold by Marvel Oil Company,
Inc., of Port Chester, New York, as a lubricant and waterproofing
agent.
A given unit not carrying the lubricant may require excessive force
causing damage to the unit when applied to a given pipe, but with
the lubricant present, the unit is found to slip on easily, the
lubricant further serving to perfect the water-tight seal.
The embodiment of FIG. 3 is adapted for use with standard 3 inch
pipes (being suitable for both cast iron and plastic pipes having
an O.D. of 3-1/2 inches, with tolerances, and copper pipe having an
O.D. of 3-1/8 inches, with tolerances).
The collar is constructed according to the same principles as
above, and in this embodiment has the same diameter mounting bead
13', the wall being correspondingly longer and having a near
horizontal extent adjacent the bead.
The following tables III and IV for this embodiment correspond,
respectively, to tables I and II of the preceding embodiment.
TABLE III
Axial distance Angle .alpha. to Unstressed Point from opening
radial plane I. Diameter
__________________________________________________________________________
A 0 84.degree. 2-1/4" B 1/4" 74.degree. 2-7/16" C 1/2" 57.degree.
2-3/4" D 3/4" 25.degree. 3-7/16" E 1" 16.degree. 5"
__________________________________________________________________________
TABLE IV
% of stressed diameter attribut- Unstressed Stressed able to
elastic Point I.D. I.D. .DELTA. distension
__________________________________________________________________________
A 2-1/4" 3-1/4" 1" 31% B 2-7/16" 3-1/4" 13/16" 25% C 2-3/4" 3-1/4"
1/2" 15- 1/2 % D 3-7/16" 3-7/16" 0 0
__________________________________________________________________________
referring now to FIG. 6, the elastomeric collar 16 is assembled
with the metal plate at the factory by a crimping operation. In
FIG. 6a is shown the relevant portion of the metal ring in cross
section, defining a trough 25 which extends a full circle about an
opening in the metal plate. The peripheral bead of the collar is
inserted in the metal trough and the combination is placed on a
crimping machine. An anvil 30 engages the lower surfaces of the
metal plate and an annular member 36 is lowered, its pressure
ensuring that the bead seats upon the bottom of the trough.
Crimping jaws 38 of matching circular configuration then move
outwardly, the jaws having a peripheral crimping surface 40 which
extends both above and below the upper edge 12e of the metal piece.
Upon radial movement of the crimping jaw, the upper edge 12e and
its margin are pressed outwardly, conforming about the bead and
pressing against or into the vertical wall W.sub.c of the collar.
The finished edge 12.sub.e ' and margin is thus pressed tightly
against and into the elastomer ensuring a tight seal and firm grip
which resists pull-out of the bead 13 from the metal piece during
application of the unit to the roof pipe.
In partial summary, the previously mentioned objects are achieved
in the following manner: (1) The essentially cylindrical sleeve
portion of the small end of the truncated bell-shaped membrane
compared with other designs such as a truncated cone or annular
disc shape, provides a superior pressure seal for any given
undistended opening diameter. (2) In addition, the inside curved
contour just below the sleeved portion of the truncated bell-shaped
membrane particularly when compared with an annular disc type
membrane provides an ease of lead in feature during installation.
This feature is completely lacking in the annular disc. (3) Also,
the additional material inherent in the truncated bell-shaped
configuration when compared with a truncated cone of comparable
dimensions or, particularly, an annular disc of equal outside
diameter, provides more material to draw from during distension
which results in less elongation of the membrane material during
installation while still maintaining the previously described
superior seal. This feature is of particular importance when other
than average roof pitches are encountered which require that the
plane of the distended opening be oriented at other than an angle
perpendicular to the axis of the upstanding pipe or conduit. The
wedge-shaped lip at the small end of the truncated bell-shaped
membrane provides added strength to that portion of the membrance
that experiences the greatest distension.
The pre-applied lubricant, as mentioned, contributes an ease of
application of the unit and further contributes to the liquid
tightness of the seal. Its use in other constructions can give
certain benefit.
Numerous modifications in the specific details including adaptation
to other sizes will be understood from the foregoing description
and are within the spirit and scope of the claims.
* * * * *