Note: Descriptions are shown in the official language in which they were submitted.
21~6~37
SEALING STRIP SUITABLE FOR SEALING A HEM FLANGE
The present invention relates to a seallng strip suitable for use in sealing a
joint between two surfaces Iying adjacent one another in generally parallel planes,
s for example surfaces (such as panels) that are butted together or overlap one
anoeher. The invention is particularly, but not exclusively, applicable to a sealing
strip suitable for use in sealing a hem flange, such as may be found on a vehicle
body. The invention also relates to a method of sealing a joint between two adjacent
surfaces.
A hem flange between two panels is formed by turning an extended edge
portion of one panel back over an edge portion of the other panel. Hem flanges can
be found in va~ious locations in vehicle bodies where two panels ~are joined
together, for example on doors, boot lids and bonnets. A vehicle door, for example7
may be formed from an inner panel and an outer panel joined together along theirouter edges by a hem flange which is formed by turning the extended edge portionof the outer panel back over the edge portion of the inner panel to form an overlap
jomt, and crimping the edges together. A seal is then needed between the edge ofthe outer panel and the adjacent surface of the inner panel, to keep moisture out of
the space between the panels and prevent corrosion.
If a vehicle door is damaged, it can sometimes be repaired by replacing only
the outer panel but, if that is done, it is clearly desirable (from the point of view of
the vehicle owner) that the repaired door should match the original as closely as
possible not only in quality but also in ~ ~ In practice, one of the most
difficult parts of the repair job is to seal the hem flange effectively and in such a way
that it closely resembles the seal on the original door, which would generally have
been formed by an automated process.
At present, one of the best ways for a vehicle repairer to seal a hem flange is
by using a liquid sealer which is extruded (for example, from a sachet or a cartridge
using an extrusion gun) on to the hem flange. The repairer requires skill, when using
the sealer, to produce a seal which is of a regular shape and matches the original.
Moreover, the liquid sealer requires a long .1.~ / ,, time before it can be
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handled, which not only delays completion of the repair work but also leaves theseal open to damage during the d.~ J~ ~ period. An additional problem, when
liquid sealer is applied firom a cartridge using an air-powered applicator, is that the
finished seal may contain air bubbles.
s Various forms of weather strip and various forms of edge guard are known
for use on vehicle doors, some of which are intended to be associated with the hem
flange. As an example, US-A4 575 147 describes an elastic molding which is
secured to the hem flange on the upper edge of a vehicle door to protect the flange
and also to intercept water flowing down oflf the vehicle roo The elastic molding
o does not seal the hem flange. As another example, US-A-4 888 919 describes a seal
member which is located adjacent the hem flange on a vehicle door so that it will
engage the vehicle body when the door is closed. In that case, the seal member
requires an upstanding flange to be provided on the turned-back edge portion of the
outer door panel. Preformed sealing strips for use in other locations are also known.
For example, US-A-4 629 648 and US-A4 654 250 both describe a caulking strip
for use as a sealant between a bath and an adjacent wall, the strip comprising abody, having a trapezoidal cross-section, which is made of a tacky rubber-based
material with a protective strip of a non-tacky polymeric film material on one side.
The present invention is concerned with the problem of enabling a joint
~o between adjacent, generally parallel, surfaces (especially a hem flange between two
panels) to be sealed co~ quickly and easily, and in a predictable and
~t"ludl-.,;l,lc manner, thereby in particular enabling the cost of vehicle repairs to be
reduced.
The present invention provides a sealing strip for sealing a joint between
two adjacent, generally parallel surfaces, the sealing strip having an inner surface for
securing the strip over the joint, and a rounded, shape-retaining, outer surface; the
profile of the strip being such that, when the strip is secured in position over the
joint, the outer surface of the strip extends from one of the said adjacent surfaces to
the other. "Shape-retaining" means that the outer surface SUb~ maintains its
rounded shape when subjected to manual pressure, or rapidly reverts - '- "~,
to its rounded shape when that manual pressure is released. In the particular case in
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which the sealing strip is for use in sealing one side of an overlap joint between edge
portions of two panels, the profile of the strip is such that, when the strip is secured
in position over the joint, the outer surface of the strip extends between the exposed
surfaces of the panels.
More specifically, the present invention provides a sealing strip for sealing a
joint between two adjacent, generally parallel surfaces, the strip having an inner
portion comprising a sealing material for securing over the joint, and a roundedouter surface comprising a non-tacky material which extends from one side of theinner surface of the strip to the other.
o The present invention also provides a method of sealing a joint between twoadjacent, generally parallel surfaces, the method comprising securing a preformed
sealing strip along the joint by means of an r " ' ~ ,, material, the~ preformedstrip having a rounded, shape-retaining, outer surface and being secured along the
joint so that the outer surface of the strip extends from one of the said adjacent
surfaces to the other and covers the adl~ ;Y~ material. In the particular case
of an overlap joint between edge portions of two panels, the strip is secured along
one side of the joint so that the outer surface of the strip extends between theexposed surfaces ofthe panels and covers the adl~ ;vw' ' ~ material.
A joint between two adjacent, generally parallel surfaces, in accordance with
the invention, includes a seal which comprises a preformed strip secured over the
joint by an a.ll~ Jse,.li..~ material, wherein the outer surface of the strip isrounded and extends from one of the said adjacent surfaces to the other, covering
the adll.,~ material. In the particular case of am overlap joint between edge
portions of two panels, the strip is secured along one side of the joint and the outer
25 surface of the strip extends between the exposed surfaces of the panels, covering
the adll~;~ material.
By way of example only, ~,..I.oJ ~ - ~ of the invention will be described
with reference to the . J;..g drawings, in which:
Fig. 1 is a d;a~alllllld~iC cross-section of a hem 'dange at the edge of a
30 vehicle door;
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Fig. 2 is a perspective view of a preformed sealing strip for the hem flange
shown in Fig. I;
Figs. 3 to 9 show alternative cross-sections, not all to the same scale, for thesealing strip shown in Fig. 2; and
Figs. 10_, 10_ and 10_ illustrate the method of applying a sealing strip to a hem
flange.
Fig. I shows a cross-section of a hem flange which, for the purposes of the
present ~Pc~rirtil~n~ is assumed to be at the edge of a vehicle door. The present
invention is, however, applicable to any hem flange (whether located in a vehicle
o body or elsewhere) and, indeed, to any joint between two adjacent, generally
parallel, surfaces.
The hem flange shown in Fig. I joins together the inner panet I and the
outer panel 2 of a vehicle door and is formed by turning the extended edge portion
3 of the outer panel 2 back over the edge portion of the inner panel I and crimping
the edges together. A seal (not shown) is then formed on the inside of the door, in
the region 4 between the edge of the outer panel 2 and the adjacent surface of the
inner panel 1, to impede the entry of moisture into the space between the panels. If
the outer panel 2 is a ~ c~ .d panel (i.e. because the vehic!e door is being
repaired), it is necessary for the repairer to replace the seal in the region 4 as well.
Fig. 2 is a general view of a preformed sealing strip 5 for use in the region 4
of the hem flange shown in Fig. 1. In cross-section, the strip S has a curved outer
surface 6 and a flat inner surface 7 although various other cross-sectional shapes are
possible as will be described below. The strip 5 is supplied on a release liner 8
(which contacts the flat surface 7) and it may be supplied in individual lengths, or it
2s may be a continuous length supplied, for example, from a roll. The manner in which
the strip 5 is used is illustrated in Figs. 10, 10_ and 10_ and will be described
below.
The strip 5 (with the release liner 8 omitted) is shown in greater detail in
Fig. 3, with a slightly different cross-section. It can be seen that, in this case, the
outer surface 6 of the strip is not completely curved but has a flattened central
section 6~, although that is not essential. The strip comprises a tacky sealing
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~156037
material 9 (for example a butyl rubber), providing a flat inner surface 7 wbich will
adhere to the door panels 1, 2, and a ~ thin outer layer 10 of a non-
tacky, harder material (for example p~ ' ) providing the outer surface 6.
The layer 10 extends completely across the outer surface 6 of the strip 5, that is
5 from the junction with the flat surface 7 on one side to the junction with the flat
surface on the other side, and in some cases may even extend further than the flat
surface 7 so that it projects slightly on both sides of the strip. The strip 5 has a
width of about lOmm and a maximum height of about 2mm; the width of the
flattened section 6_ of the outer surface is about 4mm, and the layer 10 has a
o thickness in the range of from about 0.1 to I .Omm. The strip may be formed by co-
extruding the sealing material 9 and the outer layer 10 on to the release liner 8 (Fig.
2), with the extrudate then being forcibly cooled or allowed to cool natur'ally.To use the strip S, it is simply peeled from the release liner 8, positioned at
the region 4 of the hem flange along the edge 3 of the outer panel 2 as illustrated in
s Fig. 10_ and then pressed into place as indicated in Fig. IOb so that the material 9
seals against both the inner and the outer panels 1, 2 while the outer layer 10
extends from the surface of the inner panel I of the door to the surface of the outer
panel 2, as shown in Fig. IOc. and covers the sealing material. The outer layer 10 on
the strip, being ~ hard, is not deformed when the strip is pressed into
20 place but retains its uniform appearance along the length of the hem flange. The seal
S is then ' '~, ready for the next stage of the repair process (for example,
painting).
Alternative shapes for the cross-section of the strip 5 are shown in Figs. 4 to
9, with the release liner 8 being omitted from Figs. 4 to 7 and 9, but included in Fig.
25 8. In each case, the dimensions of the strip are similar to those given above for the
strip shown in Fig. 3. COll~a~ ..d;~l~ parts of the strips carry the same reference
numerals.
The shape shown in Fig. 4 is generally similar to that shown in Fig. 3 but the
flattened central section 6_ of the outer layer 10 is extended, for example to a width
30 of about 6mm. The cross-section shown in Fig. S is similar to that shown in Fig. 2
except that the inner surface 7 is concave rather than flat, wbile the cross-section
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shown in Fig. 6 is similar to that shown in Fig. 4 except that the imner surface 7 is
stepped to match the profile of the hem flange.
Fig. 7 shows the cross-section of a strip which is similar to that shown in
Fig. 2 but in wbich the outer layer 10 extends into the sealing materiai 9 in the
s centrai region of the strip to form a ~ rib 11. As shown in Fig. 7, the ribI l does not extend to the inner surface 7 of the strip (typicailyl the height of the rib
is about l.Smm) and so wiii not prevent the strip being pressed into place on the
hem flange: however, the rib does give a harder feel to the strip and reduces the risk
that the seaiing materiai 9 will extend beyond the edges of the outer layer IO when
the strip is being pressed into place.
In the strip shown in Fig. 8, the outer layer 10 takes the form of an outer
stripofp~ u.~Lh~ orasimilar, Cu.~.~Jalali~ L ~i, non-tacky,materihi,havinga
curved outer surface 14 and a concave inner surface 15, the latter containing the
seaiing materiai 9 which is covered by the release liner 8. As shown in Fig. 8, the
outer strip 10 extends beyond, and so completely covers, the sealing material 9.Aithough the sealing strip shown in Fig. 8 could be formed by co-extrusion of the
outer layer 10 and the sealing materiai 9, it could also be assembled by applying the
seaiing material 9 in a separate operation to a preformed outer strip IO using, for
example, an extrusion device. That assembly operation could be carried out by the
~ ~;. or by the end user.
Fig. 9 shows a sealing strip which is generally similar in cross-section to thatshown in Fig. 2 except that, in this case aiso, the outer layer IO extends beyond the
sealing materiai 9. In the strip shown in Fig. 9, however, the imner surface of the
layer I O is tacky to ensure that the extended edges IO_ of the layer IO adhere to the
surfaces to which they are applied. It will be appreciated that the outer layer IO of
any of the strips shown in Figs. 3 to 7 could have ' '~ t~ ic~i edges 10_.
The preformed strips 5 shown in Figs. 4 to 9 are all applied to a hem flange
in the same way as the strip shown in Fig. 2, that is: the release liner 8 (not shown
in Figs. 4 to 7 and 9) is removed, the strip 5 is positioned at the region 4 of the hem
flange along the edge 3 of the outer panel 2 of the vehicle door as illustrated in Fig
10_, and is then pressed into place as indicated in Fig. IO_. When the strip is in
21~603~
position, the material 9 seals against both the inner and outer panels 1, 2 of the
vehicle door and is covered by the outer layer 10 of the strip, which still has its
original rounded shape (at least ' ".y) and extends firom the iMer panel I to
the outer panel 2, as shown in Fig. 10~. The seal can then be handled " 1~,.
Preferably, when any of the above-described strips 5 is applied to a hem
flange, the outer layer 10 of the strip 5 actually touches the surface of the immer
panel I at one side and the surface of the outer panel 2 at the other side so that it
extends, '~, from one surface to the other. In practice, however, there can
be a small gap between one or both sides of the outer layer 10 and the surface of the
o adjacent panel 1, 2 without detriment to the sealing function of the strip. Such a gap
may be covered by any coating, for example paint, that is ' 3 ~ , applied over
the strip.
As an alternative, in the case of the sealing strip shown in Fig. 8, the sealingmaterial 9 and the outer strip 10 could be supplied, and applied to a hem flange, as
separate , (the sealing material being supplied in strip form on a release
liner). A hem flange would then be sealed by applying the sealing material to the
region 4 of the hem flange along the edge 3 of the outer panel 2, removing the liner,
and then applying the outer strip 10 to the sealing material. The finished seal would
be the same as that achieved using the preformed strip 5 shown in Fig. 8.
Although the sealing material 9 of the strip 5 is tacky and does not normally
require an adhesive to secure it to the panels 1, 2, it is possible to use an adhesive if
preferred. The adhesive could be coated onto the inner surface 7 of the strip as the
latter is being formed on the release liner 8 (Fig. 2) or it could be coated onto the
region 4 of the hem flange before the strip is applied to the flange. Alternatively, the
strip could be formed completely from a non-dl~f~-rm~ P non-tacky material whichnecessarily requires an adhesive to secure it to the panels I, 3. Any suitable adhesive
could be used (including, for example, a hot-melt adhesive), and in this case the
inner surface 7 of the strip is preferably stepped as shown in Fig. 6 to match the
profile of the hem flange. As a still further alternative, the strip could be formed
completely from a Ih ~pl ';' ' material and would be secured to the hem flange
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by first applying heat to the inner wrface of the strip so that it melts and then
pressing the molten surface against the hem flange.
When the strip S comprises a tacky sealing material 9 with a non-tacky outer
part 10 as shown in Figs. 3 to 9, suitable alternative materials to the butyl rubber
5 mentioned above include pul~D~l~h;d~, p~ly~ u~ silicone and acrylic
rubbers. As a further alternative, the tacky sealing material could be one that does
not remain tacky but will cure, for example in response to applied heat, radiation or
moisture, after it has been pressed into place on the hem flange. Suitable
Ih ., - ~C. ~ materials include blocked p~ h~ ," and blocked i;,u~, and
o epoxies; suitable radiation-curable materials include acrylates, epoxies and acrylate
hybrids; and suitable moisture-curable materials include j~,,y~ l t~ and
~ " y~ . Suitable alternative materials to pUlyul~ for the outer part lû
of the sealing strip include polyolefins (for example, p~4~ o and
p~ly~J.u~ ) and polyvinyl resins.
Generally, it is required that the rounded outer surface of the strip 5 should
C~ y maintain its rounded shape when subjected to manual pressure (for
example when being pressed into place over a joint) or should ! ' ' '- "~ revert to
that rounded shape when the manual pressure is released. When the strip S has anouter layer 10 that extends beyond the sealing material 9 as shown in Figs. 8 and 9,
20 the extended edges of the outer layer may deflect slightly when the strip is pressed
over a joint, although the generally rounded shape of the outer layer should be
maintained. It is desirable to be able to reposition the strip when it is being applied
but also desirable that the adhesion of the strip to the pamels 1, 2 should become
permanent once the strip is in place. It is also desirable that the final seal should be
2s able to withstand; , ~Lul~,~ over at least the range -3û C to +90 C.
The outer surface of the part 10 of the sealing strip could be textured, if
desired.
Although the above description refers specifically to a hem flange on a
vehicle door, use of the sealing strips described is not restricted to that location or,
30 indeed, to use on hem flanges. The sealing strips could, if apl,lul)l , be used for
any similar sealing job in any location, for example the sealing of a lapped joint or
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any other joint between two adjacent, generally parallel, panels or surfaces. It will
also be a~ e I that the various shapes described for the sealing strips can be
modified to suit the locations in which they are to be used.
Each of the sealing strips 5 described above with reference to the drawings
5 enables a hem flange to be sealed quickly and easily, and can be handled as soon as
it has been applied. Sealing strips of the type described can be applied ~ r~ l~" ll~,
without puckering, even when the line of the hem flange is curved (for example, at
the top of a vehicle door). The resulting seal is effective in that it provides good
corrosion resistance, and is uniform in 1lr Moreover, although the above
o description refers to the sealing strips being used in the repair of vehicles ( in which
case the shape of a sealing strip can be selected so that the finished seal will closely
resemble the original) they could also be used to seal the hem flanaês of new
vehicles. In the case of a vehicle repair, the paint applied over the seal will
generally be one that cures at a comparatively low baking Le~ ,.a~u~ (typically a
5 L~ p~.aLul~ of about 60 to 80C) and the sealing strip used should be able to
withstand at least such a L~ .aLul~;. In the l..a..ur~Lu.~; of a new vehicle, on the
otherhand, apaintwithahigherbaket~ ,.aLu.t;(typicallya Lélll~,.aLul~;ofabout
140C) would be used and a sealing strip that can withstand those higher
t~ J.,ldLul~ would be required.
