Electricity: conductors and insulators – Conduits – cables or conductors – Single duct conduits
Reexamination Certificate
2001-08-29
2002-12-03
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Single duct conduits
C174S068300, C174S135000, C016S002200, C248S056000, C439S604000
Reexamination Certificate
active
06489559
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a grommet and particularly to a grommet that can be assembled onto a wiring harness and mounted in a through hole in a body panel of an automotive vehicle. The grommet protects the wiring harness and makes a portion where the wiring harness introduced into the through hole waterproof, dustproof and soundproof.
2. Description of the Related Art
A grommet typically is mounted on a wiring harness that will extend from an engine compartment to a passenger compartment of an automotive vehicle. The grommet and the wiring harness than are mounted in a through hole of a body panel that partitions the engine compartment from the passenger compartment. Accordingly, the grommet protects the wiring harness at the through hole and prevents the flow of water, dust and sound from the engine compartment to the passenger compartment.
A grommet of the type described above is referred to as a “one-motion grommet” and has a body-locking recess around its outer periphery. The body locking recess is configured to be engaged with the surrounding edge of a through hole of a body panel merely by pushing the grommet into the through hole in one direction. A one-motion grommet has the potential for easy mounting.
A known one-motion grommet is disclosed in Japanese Unexamined Utility Model Publication No. 4-42982 and also is identified by the numeral
1
in
FIG. 10
herein. The grommet
1
has small-diameter tubes
2
and
3
at opposite ends of the grommet
1
and a widened tube
4
between the small-diameter tubes
2
and
3
. A body locking recess
5
is formed in the outer circumferential surface of the widened tube
4
, and a cut-away portion
6
is formed at the radially inner side of the body locking recess
5
.
The grommet
1
is pushed in the direction of arrow Q from an engine compartment (X) to a passenger compartment (Y). As a result, a slanted wall
5
a
of the body locking recess
5
is deformed inwardly into the cut-away portion
6
, and is enabled to pass through a through hole
9
formed in a body panel
8
. The slanted wall
5
a
is restored to its original shape after passing through the through hole
9
, so that the body panel
8
is locked between the slanted wall
5
a
and another side wall
5
b.
The cut-away portion
6
extends from an opening
6
a
beyond a position radially inwardly of the body locking recess
5
to facilitate the inward deformation of the slanted wall
5
a
when the grommet
1
is being pushed into the through hole
9
. The cut-away portion
6
then is bent radially outwardly beyond the body locking recess, so that a back end
6
b
of the cut-away portion
6
reaches substantially the same radial position as a groove bottom surface
5
c
of the body locking recess
5
.
The base of the slant wall
5
a
is thinner at its outer circumference than at its inner circumference. As a result, the cut-away portion
6
is likely to cause the slanted wall
5
a
to deform outwardly when the body panel
8
contacts an outer circumferential surface
4
a
of the widened portion
4
adjacent the back end
6
b
of the cut-away portion
6
. Deformation of the slanted wall
5
a
outwardly instead of inwardly will cause the slanted wall
5
a
to abut against a wall surface
8
a
of the body panel
8
at the side from which the grommet
1
is pushed, as shown in FIG.
4
(B). Hence, it will be difficult to insert the grommet
1
into the through hole
9
. More particularly, the cut-away portion
6
that is formed to facilitate the inward deformation of the slanted wall
5
a
may actually cause the slanted wall
5
a
to deform outwardly and in a direction opposite from the desired direction. This complicates the insertion of the grommet
1
into the through hole
9
and requires a larger insertion force.
The through hole of the body panel may be oblong. However, the small diameter tube is usually circular. As a result, the cut-away portion
6
may be large along one axis and small along a second axis. If the cut-away portion is excessively large along the longer axis, the surrounding wall where the body locking recess is formed enters the cut-away portion. Consequently, the body locking recess may pass through the through hole.
The cut-away portion is formed inside the side wall of the body locking recess to facilitate the inward deformation of the side wall of the recess. However, the side wall may be inclined excessively inwardly to cause the body locking recess to pass through the through hole both when the grommet is pushed into the through hole of the body panel, and when the grommet is pulled through the through hole. This may occur when the through hole is oblong and the widened tube portion formed with the body locking recess is circular, and when the through hole and the widened tube portion are both circular.
In view of the above problems, an object of the invention is to improve a mount ability of a grommet by causing a side wall of a body locking recess to be easily and securely deformed inwardly during insertion of a grommet into a through hole in a body panel.
SUMMARY OF THE INVENTION
The invention is directed to a grommet that is insertable into a through hole in a body panel in one direction, and that can be engaged with the through hole while mounted on a wiring harness. The grommet may be unitarily formed from a rubber or elastomer, and comprises first and second small-diameter tubes at opposite longitudinal ends of the grommet. The first small-diameter tube defines the front of the grommet with respect to the insertion direction of the grommet into the through hole, and hence the second small diameter tube defines the rear end of the grommet.
The grommet further comprises a widened tube between the first and second small-diameter tubes. The widened tube includes a cut-away portion that extends forward into the rear end of the widened tube and that opens toward the rear end of the grommet. Thus, the cut-away portion branches the widened tube into an outer tube and an inner tube. The inner tube is substantially continuous with the second small-diameter tube.
A body locking recess is defined in the outer tube. The body locking recess is more backward than the forward end of the cut-away portion along the longitudinal direction of the grommet. Additionally, the forward end of the cutaway portion preferably is more radially inward than the radially inward bottom end of the body locking recess. Thus, at least a portion of the outer tube will deform inwardly toward the cut-away portion in response to forces exerted by the body panel on the insertion side of the outer tube while the grommet is being pushed into the through hole in the body panel.
The body locking recess preferably is defined partly by front and rear projections on the outer surface of the outer tube. The front projection has a forwardly and outwardly facing slanted surface and a substantially radially aligned rearwardly facing surface that defines the forward side of the body locking recess. At least the forward end of the cut-away portion preferably is more radially inward than the slanted surface. These relative positions ensure that at least a portion of the outer tube will deform inwardly toward the cut-away portion in response to forces generated by the body panel on the slanted surface of the outer tube as the grommet is being pushed into the through hole in the body panel. Thus, unlike the above-described prior art, there is no possibility that the slanted surface of the annular front wall will deform radially outward in response to forces exerted by the body panel as the grommet is urged into the through hole. Accordingly, insertion of the grommet into the through hole is carried out smoothly.
The back end of the cut-away portion preferably has an opening side with an outer circumferential surface that is flared outwardly to widen toward the opening end of the cut-away portion. The outwardly flared surface preferably is radially inward from the annular rear wall of the outer tube. The base end of the slanted sur
Hashimoto Takeshi
Nakata Hiroyuki
Casella Anthony J.
Hespos Gerald E.
Patel Dhiru R
Reichard Dean A.
Sumitomo Wiring Systems Ltd.
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