Electrical connectors – With relatively guided members and intermediate pliable... – Relatively movable about axis
Reexamination Certificate
1999-07-21
2001-10-23
Bradley, Paula (Department: 2833)
Electrical connectors
With relatively guided members and intermediate pliable...
Relatively movable about axis
C439S015000, C439S034000
Reexamination Certificate
active
06305958
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cable reel, also known as a rotary connector, used in steering systems. The steering system includes a steering wheel installed in vehicles such as automobiles. The invention also relates to a method of assembling such a cable reel, in which the number of assembly steps is reduced.
2. Description of Background Information
In automobiles, a cable reel—or rotary connector—is used for electrically connecting electrical equipment installed on a steering wheel to chassis-side circuits. The mounting of the assembly shall be described with reference to
FIGS. 1 and 2
. The cable reel
1
is wound with a flat cable, and includes a rotor
5
which is rotatable within a cylindrical casing
2
. As shown in
FIGS. 1 and 2
, the cylindrical casing
2
is fixed onto a combination switch body
3
, which in turn is fitted to a steering column
4
. On the other hand, there is provided a rotor
5
which rotates with a steering wheel. When the cylindrical casing
2
and the rotor
5
are assembled, they form a cylindrical space in which the cable reel
1
is installed such that the flat cable
6
is wound around the cable reel
1
in the manner of a coiled hairspring. End portions of the flat cable
6
are joined, respectively, to a first connector and a second connector. The first connector is fixed to the cylindrical casing
2
, whereas the second connector is fixed to the rotor
5
. An electrical cable is joined to each of the connectors
7
and
8
by one of its end portions, the other end portion of the cable being led out from the above assembly. As the rotor
5
rotates clockwise or counterclockwise relative to the steering wheel, the flat cable
6
can be made correspondingly tight or loose in the cylindrical space.
The method of assembling cable reel
1
is shown in FIG.
3
. In this figure, a flat cable
6
is unrolled from a coiled reel
10
of flat cable
6
, with the unrolled part of the flat cable temporarily set aside in a looped state. After a predetermined length of flat cable
6
is unrolled, the unrolled flat cable
6
is cut off from the rest of the reel
10
. Both ends of the temporarily looped length of flat cable
6
are then respectively connected to a first connector
7
and a second connector
8
, both of which are already connected to a respective electrical cable w. To connect the flat cable
6
to the first connector
7
and second connector
8
, the elongate conductive portion (copper strip) of flat cable
6
is first welded to the core portion of electrical cable w. Then, the welded parts are each held by a connector housing.
In order to connect the flat cable
6
to the connectors
7
and
8
, the temporarily looped flat cable
6
has to be straightened out. Then, one end portion of flat cable
6
is joined, e.g. to connector
7
, whereas the other end portion is joined to connector
8
. After the connector
7
is fitted to a top plate of rotor
5
, the flat cable
6
is wound around the axial direction of rotor
5
. On the other hand, connector
8
, which is joined to the other end portion of flat cable
6
, is fixed to a cylindrical casing
2
. The rotor
5
is then assembled into the cylindrical casing
2
in a freely rotatable manner, as shown in
FIGS. 1 and 2
.
According to the known method of assembling a cable reel described above, three assembling steps are required:
1) unrolling a flat cable from a coiled reel and temporarily keeping the unrolled flat cable in a looped state;
2) stretching out the spiraled flat cable and joining a connector to each end thereof, and
3) winding the flat cable around the axial direction of a rotor.
This requires the series of steps including temporarily spiraling, straightening, and winding a flat cable. Such a handling process requires considerable labor and costs.
In view of this state of the art, the present invention intends to simplify the above process steps, reduce production costs, and improve productivity.
SUMMARY OF THE INVENTION
According to one aspect of the invention, there is provided a cable reel including a cylindrical casing having at least an end opening, a rotor mounted into the cylindrical casing in a freely rotatable manner, thereby forming a cylindrical space between the cylindrical casing and the rotor, and a flat cable, wherein the rotor is in the shape of a reel having a barrel portion with two ends, the two ends being provided with a top plate and a bottom plate respectively, each plate diametrically projecting from the barrel portion, the flat cable being wound around the barrel portion of the rotor and contained in the cylindrical space, and the top plate of the rotor being arranged such as to close the end opening of the cylindrical casing when the rotor is mounted into the cylindrical casing.
The present invention also provides a method of assembling the above cable reel, including:
a) unrolling the flat cable having a first end portion from a coiled reel;
b) fixing a first connector to the first end portion of the flat cable;
c) preparing the rotor having the barrel portion, and providing the top plate with a fixing notch;
d) fitting the first connector into the fixing notch;
e) winding the flat cable around the barrel portion of the rotor up to a predetermined length as the flat cable is being unrolled from the coiled reel;
f) cutting off the flat cable, so as to form a second end portion;
h) fixing a second connector to the second end portion; and
I) mounting the rotor wound with the flat cable into the cylindrical casing in a freely rotatable manner.
According to another aspect of the invention, there is also provided a method of assembling a cable reel, the cable reel including a cylindrical casing having at least an end opening, a rotor including a barrel portion, and a top plate diametrically projecting from the barrel portion, thereby substantially forming a T-shaped cross-section, the top plate being adaptable for the end opening, and a flat cable wound around the barrel portion, the method including:
a) unrolling the flat cable having a first end portion from a coiled reel;
b) fixing a first connector to the first end portion of the flat cable;
c) preparing the rotor having the barrel portion, and providing the top plate with a fixing notch;
d) fitting the first connector into the fixing notch;
e) winding the flat cable around the barrel portion of the rotor up to a predetermined length as the flat cable is being unrolled from the coiled reel;
f) cutting off the flat cable, so as to form a second end portion;
g) fixing a second connector to the second end portion; and
h) mounting the rotor wound with the flat cable into the cylindrical casing in a freely rotatable manner, so that the top plate is fitted to the upper-side opening of the cylindrical casing, whereby a cylindrical space is formed between the cylindrical casing and the rotor and the flat cable is contained in the cylindrical space.
As mentioned above, the end portion of the flat cable just drawn out from the coiled reel is immediately fixed to the first connector. The flat cable can thus be wound directly around the barrel portion of the rotor as it is being unrolled from the reel coil. As a result, the step of temporarily spiraling the flat cable after having unrolled it from the coiled reel and before fixing it to the connector is no longer needed. The present invention can thus eliminate this process step, even though it was deemed unavoidable in the prior art.
Since the flat cable drawn from the flat cable reel has to be wound directly around the barrel portion of the rotor, the rotor is preferably also in the form of a reel. In this way, the wound flat cable is prevented from springing off the rotor's barrel portion. In the reel-shaped rotor, the top and bottom plates of the rotor (which thereby form flanges) may be designed such that the distance separating the two plates at least roughly corresponds to the width of the flat cable, such that the clearance between the plates is minimized. As a result, the flat cable can be r
Maegawa Akihito
Sugata Shoichi
Bradley Paula
Greenblum & Bernstein P.L.C.
Nguyen Truc
Sumitomo Wiring Systems Ltd.
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