Note: Descriptions are shown in the official language in which they were submitted.
~037430
AE-352 ~ l-- PArrENT
AIRBAG CONNECTING DEVICE
i~IELD OF THE INVENTION:
The invention concerns a connecting device for
connecting a stationary current connection to a current
connection rotating therearound, with a housing comprising
a housing bottom and a housing cover which is rotatable
~herearound, and with a flat conductor cable which is wound
S as a spiral and which at the ends of the spiral is bent over
forming ends which extend away at 90, wherein the spiral is
disposed in the housing and the ends which are bent over at
90 issue from the housing, and with openings in the flat
conductor cable.
BACKGROUND OF THE INVENTION:
A connecting device of that kind is known (US Patent
No. 4,824,396). Connecting devices of that kind are used
for example in the hubs of the steering wheels of motor
vehicles. ~ncreasingly, disposed in motor vehicle steering
wheel hubs is a buffer gas bag which is inflated in
fractions of a second in the event of substantial
deceleration That is effected by means of a firing capsule
which is operative as a gas generator. The buffer gas bag
and the firing capsule turn witA the steering wheel. The
steering column, through which the current for the firing
capsule is supplied, is stationary. Now, the known
connecting device just referred to ~bove connects the
rotating current connection of the firing capsule to the
2S stationary current connection in the steering column. The
spiral which is wound from the flat conductor cable is wound
in a loose configuration with large clearance and spaces
between the individual turns of the spiral. When the
steering wheel is turned in one direction the spiral is
further wound up and the windings are tightened towards each
other. When the steering wheel is turned in the other
direction, the spiral is unwound and the turns move away
from each other to a certain extent. In that way the two
current connections are always connected together in the
3S same manner by way of the conductors of the flat conductor
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1 cable, ~ven upon ~ rotary movement of ~he steering wheel.
In addition to the firing capsule, it is also possible to
envisage connection further current consumers or switches
disposed in the steering wheel to a stationary current
connection.
In order to achieve a high degree of elasticity, in
order to provide for a low weight and in order to reduce the
level of costs, a connecting device of the specified kind
uses a flat conductor cable of small conductor cross-
sections. That means however that the mechanical strength
thereof is reduced. During the service life of a motor
vehicle, the steering wheel thereof will be turned backwards
and forwards innumerable times. That means that the flat
conductor cable and in particular the ends thereof which
lS issue from the housing are subjected to mechanical loadings
sur~MARy OF THE INVENTION:
The invention is based on the object of so designing a
connecting device of the specified kind that the flat
conductor cable and in particular the ends thereof which
2~ issue from the housing are mechanically protected. The
invention further seeks to provide that the connecting
device is of such a configuration that the flat conductor
cable, with its spiral and its two ends which extend away at
90, can be connected to the housing easily, quickly and
inexpensively. In that regard the invention seeks to
provide that the desired high mechanical strength is
maintained.
To attain that object, in a connecting device of the
kind set forth in the opening part of this specification,
the invention provides that in the transitional regions
between the spiral and the two ends which extend away at
~0, the flat conductor cable is enclosed in a respective
sheathing, the sheathings have portions embracing the ends
of the spiral and the ends which extend away at 90, and the
portions embracing the ends of the spiral are located to the
housing bottom and the housing cover. The spiral which is
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1 disposed in the housing is subjected to scarcely any
mechanical loading. It is only wound up tighter and
unwound. The flat conductor cable can readily withstand
that loading, by virtue of its elasticity. The flat
conductor cable is subjected to a severe mechanical loading
at its ends and in particular at its end which is disposed
in the rotatable housing cover. At those ends or in the
transitional regions between those ends and the spiral, the
flat conductor cable is further connected to the housing
bottom and the housing cover. At those endangered
locations, in accordance with the invention, the flat
conductor cable is mechanically stabilized and protected by
the sheathings. The sheathings then also present themselves
for connecting the two ends of the spiral to the housing
bottom and the housing cover. That is effected with the
locating arrangement according to the invention. The
locating action can be produced in a very simple manner. In
other words, the flat conductor cable or the spiral wound
therefrom, with the two ends extending away at 90, can be
very quickly and easily fixed in the housing.
In an advantageous embodiment, the invention provides
that the sh~athings are injected onto the flat conductor
cable and the plastic material forming them is _aused to
flow into the openings provided in the sheathing of the
cable, forming a means for relieving a pulling force
~hereon. The openings provided in the sheathing of the flat
conductor cable increase the elasticity thereof. In
accordance with the invention the sheathings can be anchored
in the openings in the flat conductor cable. In that way
the sheathings are firmly connected to the flat conductor
cable. The cable is mechanically stabilized and relieved of
the load of pulling forces thereon.
So that said sheathings do not adversely affect the
flexibility of the flat conductor cable, a further
configuration of the invention provides that the portions
forming them have annular portions which are separated by
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_ 4-
1 openings, and limb portions connecting said annular
portions. The annular portions which are separated by
openings and which are connected by limb portions have
almost the same degree of flexibility as the flat conductor
cable itself. The above-mentioned portions embrace the ends
of the spiral and the ends thereof which extend away at 90.
Accordingly, the portions forming a sheathing also define an
angle of 90.
The enhanced flexibility of the sheathings is not
required everywhere. It is sufficient for the sheathings to
be particularly flexible only over the ends of the flat
conductor cable, which extend away from the spiral. For
that purpose the invention provides that the portion forming
the sheathings has said annular portions which are separated
1~ by openings, and the limb portions connecting the annular
portions, only in the region leading from the spiral to the
ends of the flat conductor cable which extend away
~herefrom. It is further sufficient for those portions
which afford the increased degree of flexibility to begin
~o only at a spacing from the spiral.
The housing comprises a housing bottom and a housing
cover. In regard to the configuration of the housing cover
and the location of the one sheathing to said cover, the
invention provides that the housing cover has a cover plate,
a hub in the form of a tubular portion, and an outer casing
portion, and the hub has an opening which is delimited by
two sides and the portion of the one sheathing is located in
the opening. In terms of the principle of the invention,
the way in which the one sheathing is located in the opening
33 is immaterial. It is particularly expedient for the portion
vf the 3ne sheathing to have a thickened portion and for the
latter to be located between the two sides. It may simply
be clamped in position between them. To provide for further
mechanical stabilization and also to afford mechanical
protection for the end of the spiral, a further
configuration provides that said portion, adjoining the
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1 thickened portion, has a further portion which bears against
he outside surface of the hub. That means that the
sheathing also embraces the spiral in the initial portion
thereof, and mechanically stabilizes same. Likewise the
thickened portion is better held in the opening between the
two sides thereof. It cannot slip away radially inwardly as
it is resisted by the portion which bears against the
outside surface of the hub. In regard to the configuration
of the housing bottom and the location of the sheathing
provided at the other end of the spiral, the invention
provides that the housing bottom has a bottom plate and an
inner casing portion and the latter has an opening and the
portion of the one sheathing is located in the opening. In
regard also to this locating action, the way in which the
locating effect is specifically produced is immaterial in
terms of the principle of the invention. It has been found
to be particularly ~dvantageous for the portion to have a
thickened portion and for the latter to be located in the
opening. A particularly good locating effect is achieved if
the sides defining the opening have a tongue and a groove
and the thickened portion has a groove and a tongue which
can be engaged with them. In a particularly advantageous
conriguration the portion of the sheathing provided at said
end of the spiral, adjoining the thickened portion, has a
further portion which bears against the inside surface of
the inner casing portion. That arrangement also provides
for mechanical stabilization of the spiral in the end
portion thereof.
The firing capsule forming the gas generator for the
3~ buffer gas bag is connected to its voltage source or firing
device by the connecting device. Likewise switches or
contacts for actuating the horn or hooter, for actuating the
headlamps, for actuating measuring devices and the like may
be connected in that way. Flat conductor cables with more
than two conductors are used for that purpose. In order to
facilitate the connection of a plurality of current
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consumers or switches, in a further embodiment the
invention provides that the flat conductor cable is slit
in its longitudinal direction at its ends which issue
from the housing, forming at least two conductor
portions. That arrangement provides two or more
conductor portions which can be taken separately from
each other in different directions and connected to
current consumers or switches. The same purpose is
served by a further feature according to the invention
which provides that the portions of the sheathings, which
issue from the housing, are bent over with respect to the
center line of the housing. Generally the portions
embracing the conductor portions are bent over outwardly.
That is due to the fact that there is space there for the
conductor portions. In other words the conductor
portions of the flat conductor cable are also guided a
short distance outside of the housing and thus
mechanically stabilized. That also enhances the service
life of the entire connecting device.
It is stated hereinbefore that the housing cover is
rotatable and the housing bottom is thus stationary.
Likewise reference was made to a beginning and an end
portion of the spiral. Those terms are relative. It
would likewise be possible to say that the housing cover
is stationary and the housing bottom is rotatable about
the cover. The terms beginning and end portions of the
spiral can also be interchanged.
Generally speaking and in summary of the foregoing
the present invention may be considered as providing an
electrical cable assembly for use in a connector for
electrically coupling a stationary connection to a
movable connection which is rotatable with respect to the
stationary connection, the cable assembly comprising: an
elongate flat cable having plural elongate, transversely
spaced conductors supported by a cable insulator, the
flat cable having opposed ends for electrical connection
to the stationary connection and to the movable
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connection, and a central region therebetween which
provides for relative movement between the ends, the
opposed cable ends extending from the central region at
opposed 90 angles therefrom thereby defining a bent
transition portion between the central region and each
end; and a protective sheathing formed over a portion of
each of the ends of the flat cable, adjacent portions of
the central region and the bent transition portions, the
sheathing including a series of longitudinally spaced
annular portions along the cable ends and the central
region adjacent the bent transition portions and a solid
portion at the bent transition portions, adjacent annular
portions being separated by an opening which provides for
longitudinal flexing of the flat cable at the ends, and
along the central region while preventing flexing at the
bent transition portions.
BRIEF DESCRIPTION OF THE DRAWINGS:
Figure 1 is a perspective view of the spiral and the
two ends which extend away therefrom at 90.
Figure 2 is a plan view of a beginning or end
portion of the spiral and two conductor portions which
extend away therefrom at 90.
Figure 3 is a view in cross-section through the flat
conductor cable taken along section line III-III in
Figure 2.
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2~37430
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1 ~igure ~ is a plan view similar to that shown in Figure
~ but with a sheathing fitted onto the conductor portions of
the flat conductor cable.
Figure 5 is a view in section taken along section line
V-V in Figure 4.
Figure 6 is a perspective view of a part of said
sheathing.
Figure 7 is an exploded perspective ~iew of the housing
cover and the beginning portion of the spiral with the
sheathing embracing same.
Figure 8 is a perspective view of the housing cover and
the sheathing located thereto.
Figure 9 is an exploded perspective view of the housing
bottom and the end portion of the spiral with the sheathing
i5 embracing same.
Figure 10 is a perspective view of the housing bottom
and the sheathing located thereto.
Figure 11 is a perspective view of the housing composed
of the housing bottom and the housing cover.
Figure 1 shows a four-wire flat conductor cable 22 with
its two ends each divided into two conductor portions 24.
In its middle region the flat conductor cable 22 is wound to
form a spiral 26. In its middle region the flat conductor
cable 22 is wound to form a spiral 26. The conductor
portions 24 extend in planes which define an angle of 90 to
the spiral 26. In accordance with the view shown in Figure
2, that is due to the fact that the conductor portions 24
are bent over througn 90 along fold lines 28 relative to
the two ends of the spiral 22. Cable openings 30 are
3~ provided over the entire width and also at the edges of the
insulation of the flat conductor cable 22.
Figures 4 and 5 show the sheathing 32 which is injected
from plastic material and which embraces the two ends of the
spiral 26 and a part of the conductor portions 24 which
extend away therefrom. The sheathing 32 which is provided
in duplicate, comprises two sheathing portions 34 and 36.
2037~30
-8-
1 They include an angle of 90 to each other. As Figure 6 in
particular shows, the sheathing 32, at its end which is at
top right in Figure 4, has annular portions 38, sheathing
openings 40 separating the annular portions, and limb
portions 42 connecting same. As Figure 4 shows, only the
end of the portion 36 of the sheathing 32, which is at top
right, is of that configuration. That portion 36 embraces
the conductor portions 24 which extend away from the spiral
26. At a spacing from the spiral 26 which is not shown in
Figure 4, or the portion 34 which leads to the spiral, the
sheathing 32 has the annular portions 38 with the sheathing
openings 40 and the limb portions 42, which enhance the
flexibility thereof. It is only there that the conductor
portions must retain their high degree of flexibility for
1~ the purposes of connection to the stationary current
connection. That high level of flexibility is not required
in the portion 34 which leads to the spiral 26. For the
purposes of simplifying the illustration, that configuration
of the sheathing with the annular portions 38, the sheathing
openings 40 and the limb portions 42 are not illustrated in
Figures 7 through 11.
In the view shown in Figure 7, the sheathing has a
thickened portion 44 between its two portions 34 and 36.
Figure 7 further shows the housing cover 46 with the cover
plate 48, the outer casing portion 50, the hub 52 with the
hub opening 54 and the two sides 56 and 58 defining the hub
opening 54. The housing cover 46 is a known self-contained
component. The two conductor portions 24 together with the
spiral 26 are pushed into the central aperture of the hub
52, in the direction of the arrows shown in Figure 7. That
gives the configuration shown in Figure 8. The thickened
portion 44 lies in the hub opening 54 between the two sides
56 and 58. In that case the side 58 may have a groove and
the thickened portion 54 may have a projection. That is
indicated in Figures 7 and 8. Irrespective of the detailed
construction, however, the thickened portion 44 is clamped
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g
1 in position in the hub opening 54. In that arrangement the
portion 34 of the injected sheathing lies with a further
portion 80 against the outside surface of the hub 52.
As shown is Figure 9 the housing bottom 60 has a bottom
plate 62 and an inner casing portion 64. A plate opening 66
is provided in the latter. A tongue 68 and a groove 70 are
provided in the sides of the inner casing portion 64, which
define the plate opening 66. The portion 34 of the
sheathing which embraces the end portion of the spiral 26 in
turn has a thlckened portion 72. A groove 74 and a tongue
76 are also arranged at the sides thereof. For the purposes
of assembly, the thickened portion 72 together with the
spiral 26 is moved towards the housing bottom 60 in the
direction of the arrow indicated in Figure 9. When that
happens the tongue 68 is pushed into the groove 74 and the
tongue 76 is pushed into the groove 70, resulting in the
configuration shown in Figure 10. The portion 34 bears
against the inside surface of the inner casing portion (64)
with a portion 82 adjoining the thickened portion 72. The
2~ spiral 26 is now firmly located or connected to the housing
bottom 60.
Figures 9 and 10 further clearly show that the portion
36 is bent over outwardly relative to the portion 34. The
conductor portions 24 are also bent over outwardly in a
corresponding fashion. Generally speaking, there is more
space in the direction in which the conductor portions 24
then extend, than directly beside the housing bottom 60.
Attention has already been directed to the advantage
deriving therefrom.
3~ After the assembly operation, as shown in Figures 7 and
9, the configuration is as illustrated in Figure 11. Figure
11 shows the housing 78 of the connecting device which is
now finished, consisting of the housing bottom 60 and the
housing cover 46.
