Note: Descriptions are shown in the official language in which they were submitted.
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WASHER FOR ROOFING INSULATION
This application is a division of Canadian serial number 531,603
filed March 10, 1987.
Background of the Invention
The present invention relates to a washer used to attach roofing
insulation. The washer of tbe present invention is particularly
useful in construction where single ply roofing membranes are placed
over the insulation.
The problem addressed by the present invention involves the
puncture of membrane material by fastener heads. miS problem arises
when screws which are used to secure washers and insulation to a roof
substructure become loose and move upward out of their installed
positions. Such upward movement is uaually attributable to vibration
of some sort.
Attempts to eliminate this problem have taken several forms. For
example, U.S. patent 4,361,997 to DeCaro shows engagement between the
threads o~ a screw and the walls of a bore in a washer. Another
attempt is the Tap Deck-S ~fastener in which an annular ring on the
shank of a fastener snaps through the aperture in a washer. A third
attempt is shown in Fig. 3 of U.S. patent 4,074,501 to Sandquist.
Sandquist shows a groove formed in a beveled bore. The edges of a
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countersunk screw head fit into the groove, and tend to
prohibit backward motion of the screw.
U.S. Patent 4,380,413 to George G. Dewey, which
is owned by the assignee of the present invention, shows a
screw and washer combination in which the head of a screw is
loosely captivated within a recess in the washer.
Accordingly, the present invention seeks to
provide a roofing insulation washer which prevents backward
motion of a screw during vibration.
Further, the invention seeks to provide a washer
with means to easily and positively engage the head of a
fastener used therewith.
Still further, the present invention seeks to
provide a washer with means for firmly and resiliently gripping
the head of a fastener used therewith.
Further still, the invention seeks to provide a
washer in which engagement between the washer and the head of a
fastener is easily obtained.
Summary Of The Invention
The invention in one broad aspect provides a
washer for use in attaching insulation to a roof member with a
fastener having a head and an elongated shank, the washer
comprising a resilient non-metallic body having a central
throughbore, a shoulder formed in the throughbore for engaging
the head of a fastener, the shoulder defining and separating
upper and lower portions of said throughbore, the upper portion
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having a ma~imum lateral dimension greater than that of the
lower portion. Restraining means is formed in the upper
portion of the throughbore for engaging a portion of the
fastener head and resilient head pushing means is formed on the
shoulder for urging the fastener head into engagement with the
restraining means.
Another aspect of the invention provides a washer
for use in attaching insulation to a roof member with a
fastener having a head and an elongated shank, the washer
comprising a generally flat flange having an aperture extending
therethrough and the washer including an axially extending hub
projecting froEn the flange. Gripping means receive and hold
the head in a fixed position relative to the flange, the
gripping means including a resilient generally cylindrical
upstanding protrusion disposed around the aperture, the
protrusion including a radially inwardly extending lip disposed
on an upper inner portion of the protrusion. The protrusion is
located on the washer so as to provide a space for radially
outward deflection of the protrusion as the head snaps past the
lip. The protrusion is disposed in a recess in an upper
surface of the flange.
Still further, the invention comprehends a washer
for use in attaching insulation to a roof member with a screw
having a head and an elongated shank and with a batten strip,
the washer comprising a generally flat flange having an
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aperture extending therethrough and the aperture having a
central axis generally perpendicular to the flange. A
resilient generally hollow cylindrical upstanding protrusion
has an axis generally co-axial with the axis of the aperture,
the protrusion including a radially inwardly extending lip
disposed at an upper free end of the protrusion. The
protrusion extends in a first axial direction and is disposed
on the washer so as to provide space radially outward therefrom
to allow outward deflection of the free end as the head snaps
past the lip upon insertion of the screw into the aperture.
The washer has an axially extending hub extending in a
direction opposite the first axial direction, the hub having
means formed thereon for engaging the batten strip, the means
including shoulder means formed on legs extending radially of
said hub and generally facing the flange. The washer includes
an axially extending rib disposed between the protrusion and
the aperture for resiliently holding the head in contact with
the lip.
Further still, there is provided a washer for use
in attaching insulation to a roof member with a screw having a
head and an elongated shank, the washer comprising a generally
flat flange having an aperture extending therethrough with the
aperture having a central axis generally perpendicular to the
flange. A resilient generally hollow cylindrical upstanding
protrusion has an axis generally co-axial with the axis of the
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aperture, the protrusions including a radially inwardly
ext:ending lip disposed at an upper free end of the protrusion.
The protrusion extends in a first axial direction and is
disposed on the washer so as to provide space radially outward
therefrom to allow outward deflection of the free end as the
head snaps past the lip upon insertion of the screw into the
aperture. The washer has an axially extending hub extending in
a direction opposite the first axial direction, the protrusion
being disposed within a recess in an upper surface of the
flange and lying completely within the recess.
Brief Description Of The Drawings
Other features and advantages of the invention
will become apparent from the following specifications read
with reference to the following drawings.
Fig. 1 is a top plan view of a washer embodying
the present invention.
Fig. 2 is a side elevational view in partial
section of the washer shown in Fig. 1.
Fig. 3 is a transverse sectional view of the
washer taken along lines 3-3 of Fig. 1.
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1 Fig. 4 is a cop plan view of another embodiment of the present
invent ion .
Fig. 5 is a bottom plan view of the embodiment shown in Fig. 4.
Fig. 6 is a side elevational view of the embodiment shown in Figs. 4
S and 5.
Fig. 7 is a transverse cross-sectional view taken along lines 7-7 of
Fig. 4.
Fig. 8 is a plan view of the top of a third embodiment of the present
invention.
Fig. 9 is a side elevational view of the washer shown in Fig. 8.
Fig. 10 is an enlarged sectional view of the third embodiment of a
washer of the present invention taken along line 10-10 of Fig. 8.
Fig. 11 is a plan view of the top of a fourth embodiment of a washer
of the present invention.
Fig. 12 is a plan view of the bottom of the washer shown in Fig. 11.
Fig. 13 is a sectional view taken along line 13-13 in Fig. 11.
1 Fig. 14 is a sectional view of the washer shown in Figs. 11 through
13 in combination with a screw head retaining insert.
Detailed Description of the Invention
Figs. 1, 2 and 3 show an embodiment of the invention in which the
washer 10 is comprised of a laterally extending flange 11 having a
central aperture 12 and a protruding hub 23. A recess 14 is formed in
the upper side 22 of the flange 11. '~ithin the recess 14 there is a
cylindrical protrusion or boss 15 which extends in an axial direction
upwardly from a shoulder 20. The boss 15 is spaced laterally fr~m the
aperture 12. Between the boss 15 and the aperture 12 there is a
smaller axially extending protrusion in the form of a rib 17. An
overhanging lip 16 i~ formed on the inner free end of t~e boss 15~
As shown in Fig. 2, a screw 30 has a head 31 which is gripped by
the rib 17 and the boss 15. T'ne rib 17 is a resilient tapering rib
which engages the underside 32 of the screw head. At t'ne same time,
the lip 16 engages the peripheral edge 33 of the top side of the screw
head.
The details of the shape of the boss 15 are important. The upper
portion of the lip 16 is sloped to act as a guide for the screw head 31.
The inner wall 18 of the boss 15 is generally parallel to the axis of
the aperture 12, while the outside wall 19 of the boss 15 is sloped
inwardly fro~ bot~om to top. By placing the boss 15 in the recess 14,
two benefits are obtained. First, the upper end of the boss 15 has a
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1 space into which it may deflect during ehe movement of ehe screw head
:31 passed the lip 16. It has been found that the shape as shown in
]ig. 3 allows lateral deflection of the boss 15 without resultant
damage thereto. Also, because the boss 15 is positioned well below the
5 surface 22 on the upper side of the washer, if a screw head fails to
snap pass tbe lip 16, it will not interfere with a membrane draped over
the washer. Vibrations resulting from wind or from sources within a
structure can cause loosening and backward motion of roofing screws.
The present invention minimizes the possibility of a screw backing up
to a point where the screw head 31 projects above the upper surface 22
of the washer.
Figs. 4-7 show an alternative embodiment of the present invention.
In Figs. 4-7 the designation "a" following a refer2nce numeral is used
to designate elements which correspond to the embodiment shown in Figs.
1-3.
The embodiment of Figs. 4-7 is intended to be used with a batten
strip, as shown in Fig. 7. Batten strips are used to attach edges of
roofing membranes. The strips are then covered with a membrane sheet
which is adhesively attached to a section of underlying membrane
adjacent to the batten strip. Thus, the problem of screw heads tending
to loosen and puncture overlying membrane sheets is present with the
use of batten strips in a manner similar to the problem associated with
insulation fastening as discussed above.
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1 The embodiment of Figs. 4-7 is similar to the e~bodiment of Figs.
1-3 in that the washer lOa includes a laterally extending flange lla
and an axially excending cylindrical protrusion of boss 15a surrounds
an aperture 12a extending through the washer. m e washer further
includes a hub 23a depending from the bottom side of the washer.
However, the hub has two legs 24 and 25 which are separated by a slot
29. The legs 24 and 25 have a circumferential notch 26 formed on the
outside surface thereof. The notch 26 forms a shoulder 27 which
engages a batten strip 40 as the washer is inserted through an
aperture 41 in the batten strip.
The cooperation between the boss 15a and I screw heat is
substantially the same as the cooperaCion described with reference to
the boss 15 and the screw 30 shown in Fig. 2 and discussed above.
Figs. 8, 9 and 10 show a third embodiment of the invention for
which the designation "C" is used following reference numbers. The
third embodiment is a washer designated generally with the reference
number lOc. It includes a wide laterally extending flange 11~, and a
central throughbore 12c. Fig. 8 is a plan view of the upper surface
of the flange llc. Fig. 9 shows a hub 23c depending from the bottom
surface of the washer.
Fig. 10 is an enlarged view of a cross-section through the
throughbore of the ~asher lOc. A shoulder 20c divides the throughbore
into an upper portion 56c and a lower portion 57c is substantially
less than the maximum latter dimension of any part of the upper
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1 portion 56c. The upper portion includes a shallow recess 14c in the
extreme upper surface of the washer. ~elow the shallow recess 14c a
series of axially extending spirally disposed ribs 61c. The spiral
configuration of the series of ribs can best be seen in Fig. 8. The
innermost edges of each of the ribs 61c is tapered such that the edges
of the ribs form portions of a truncated cone having a wider opening
at its upper end and a narrower opening at its lower end.
At the lower end of the series of ribs 61c tXere is an annular
radially inwardly extending lip 16c, which operates in a manner
similar to the lip 16 of the embodiment described earlier. The lip
16c cooperates with the rib 17c, which is disposed on the shoulder
20c, to resiliently retain the head of a fastener. The rib 17c
deflects an amount sufficient to allow the head of a fastener to snap
past the lip 16c, and rib 17c is resilient so that it can push the
head of a fastener into gripping engagement with the lip 16c.
The spiral disposition of the ribs 61c is such that retrograde or
upward motion of a threaded fastener is severly restricted. However,
the insertion of a threaded fastener in a clockwise direction is
facilitated by the orientation of the ribs as shown in Fig. 8.
Specifically, a plane 70c which bisects a rib 61c is offset from a
plane 71c which is parallel to plane 70c and which bisects the central
axis 73c of the washer. It has been found that the offset between
planes 70c and 71c should preferably be-approximatel~ 0.05 inches when the ribs
are shaped in a manner similar to those shown in Fig. 8.
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1 Figs. 11, 12, 13 and 14 show a fourth embodiment of the present
invention for which a designation 'd' is added to the reference
oumbers. This fourth embodiment, generally designated as washer lOd,
combines elements of the embodiment of the Figures 4-7 and Figs. 8-10.
The washer lOd is comprised of two components, a central body 81d made
of generally resilient material and a flange 82d carried by the central
body 81d. The flange 82d contains an octagonal impression 83d formed
therein. A mating octagonal configuration is formed on the under
surface of the central body 81d to prevent relative rotation of the
two components. As with the third embodiment shown in Figs. 8, 9 and
10, the washer lOd is equipped with ribs 61d which are similar in
shape and function to the ribs 61c described earlier, and lip 16d
cooperates with rib 17d in substantially the same way in which lip 16c
cooperates with rib 17c.
lS It should be noted that the undersurface of the flange 82d, shown
in Fig. 12, includes edges 93d and corners 94d for~ed by the octagonal
impression 83d in the upper surface of the flange 82d. The edges 93d
and corners 94d project slightly below the outer clamping surfaces 95d.
This enables the edges 93d and corners 94d to engage a roofing membrane
and prevent lateral movement of that membrane. If substantial movement
of the membrane occurs at the location of the edges 93d and corners
94d, stress concentration can occur at points of contact between the
membrane and a threaded fastener, which can cause early failure of the
membrane.
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1 Another advantage of the third and fourth embodiments of the
present invention is in the abilîty of the ribs 61c and 6Ld to melt.
In some roofing application, lapping of adjacent membranes and heat
sealing thereof causes roofing insulation washers, like those of the
S present invention, to be exposed to high temperatures. When washers
like those of the third and fourth embodiment of the present invention
are exposed to high temperature, the ribs 61c and 61d melt easily
because of their large surface area. When the ribs melt, the material
comprising them flows over the head of the fastener and further
prevents rotation and backing out of the fastener.
While specific embodiments of the invention have been described
in detail above, variations and modifications will become apparent to
those skilled in the art. Such variations and modifications are
intended to fall within the spirit and scope of the appendant claims.
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