Turn signal switch device

Details Turn signal switch device Turn signal switch device

2000-06-14

2001-02-27

Friedhofer, Michael (Department: 2832)

Electricity: circuit makers and breakers

Special application

Turn indicator type switches

C200S061300, C200S061350

Reexamination Certificate

active

06194676

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a turn signal switch device attached to a steering column or the like of an automobile and serving as a direction indicator and, more specifically, it relates to a mechanism for releasing an excess load when, in a cancel operation for automatically restoring an operating lever provided in the turn signal switch device from an operating position to a neutral position, a force preventing the automatic restoring is applied to the operating lever.
2. Description of the Related Art
In the turn signal switch device of an automobile, the base end of an operating lever is rotatably supported by a housing integrally formed with the steering column or the like, and the forward end of this operating lever is rotated from a neutral position to a right or left direction indicating position, whereby a right-turn or left-turn lamp is caused to blink. In such a turn signal switch device, to retain the operating lever at three positions: the right and left direction indicating positions and the neutral position, the inner surface of the housing is provided with a cam surface, and the operating lever is provided, through the intermediation of a spring, with a driving member to be engaged with the cam surface. Further, there is provided a cancel mechanism for automatically restoring the operating lever to the neutral position when the steering wheel is turned in a direction opposite to the indicated direction, with the operating lever rotated to the right or left direction indicating position.
A known conventional example of this cancel mechanism is disclosed in Japanese Patent Unexamined Application Publication U.S. Pat. No. 5,949,040, which was proposed by the present applicant.
FIG. 9
is a cross sectional view schematically showing the construction of the turn signal switch device disclosed in the above-mentioned publication,
FIG. 10
is a front view of a movable member provided in the turn signal switch device, and
FIGS. 11A and 11B
are schematic diagrams illustrating the operation of a cancel mechanism provided in the turn signal switch device.
In these drawings, numeral
100
indicates a housing. The housing
100
is secured to a column cover, a combination switch, etc. (not shown) which is a stator member of a steering device. On the inner bottom surface of the housing
100
, a guide shaft
101
and a support shaft
102
are provided at a predetermined interval. The guide shaft
101
is fitted into a first elongated hole
103
a
of a first lever member
103
, and a second lever member
104
is rotatably supported by the support shaft
102
. The first lever member
103
has a second elongated hole
103
b
, into which a connection pin
104
a
provided on the second lever member
104
is fitted. Further, at the front and rear ends of the first lever member
103
, there are provided an abutting portion
103
c
and a cam portion
103
d
, the cross sectional configuration of the cam portion
103
d
being semi-circular. The first lever member
103
is engaged with one arm of a torsion coil spring
105
, by means of which the first lever member
103
is elastically biased in the longitudinal direction of the elongated holes
103
a
and
103
b
. A winding portion of the torsion coil spring
105
is inserted into a boss
106
provided on the inner bottom surface of the housing
100
, and the other arm thereof is engaged with the side wall of the housing
100
. Further, the second lever member
104
has a first opening
104
b
and a second opening
104
c
, and the openings
104
b
and
104
c
are opposed to each other through a support shaft
105
.
An operating lever
107
is supported by the housing
100
such that it is rotable around a support shaft
108
in the directions indicated by the arrows A and B, and inside the housing
100
, there is formed a V-shaped cam surface
109
having a pair of lock portions
109
a
on the right and left sides. A holder
110
is mounted to the operating lever
107
, and the operating lever
107
and the holder
110
integrally rotate horizontally around a straight line connecting the support shafts
108
. Inside a cylindrical portion
110
a
protruding on the front side of the holder
110
, a driving member
111
is slidably held, and the forward end of this driving member
111
is constantly held in press contact with the cam surface
109
by a spring (not shown). Further, a movable member
115
is rotatably supported by the cylindrical portion
110
a
of the holder
110
, and both arms of a return spring
116
wound around the movable member
115
are engaged with the holder
110
, whereby the movable member
115
is constantly biased toward the central stable position. Further, a cam portion
112
having a semi-circular cross sectional configuration and a receiving portion
113
hang down from the movable member
115
, and the cam portion
112
is opposed to the cam portion
103
d
of the first lever member
103
, the receiving portion
113
reaching the interior of the second opening
104
c
of the second lever member
104
.
In the turn signal switch device, constructed as described above, when the operating lever
107
is at the neutral position, the forward end of the driving member
111
abuts the central valley of the cam surface
109
, and is stably held at the position by the elasticity of a spring (not shown). At this time, as shown in
FIG. 11A
, the cam portion
112
on the operating lever
107
side and the cam portion
103
d
of the first lever member
103
are in contact with each other at their apexes, and the first lever member
103
retracts against the biasing force of the torsion coil spring
105
. Thus, the abutting portion
103
c
of the first lever
103
is positioned outside the rotation path of a cancel protrusion
114
rotating with the steering wheel; if the steering wheel is turned in this condition, the cancel protrusion
114
does not abut the abutting portion
103
c
of the first lever member
103
, and the operating lever
107
is maintained at the neutral position.
When the operating lever
107
is rotated from this neutral position in the direction of the arrow A or the arrow B, the forward end of the driving member
111
moves over the slope of the cam surface
109
and is engaged with the lock portion
109
a
, and stably held at the position by the lock portion
109
a
. For example, when the operating lever
107
is rotated in the direction of the arrow B, the movable member
115
integrally rotates with that, and the cam portion
112
and the receiving portion
113
of the movable member
115
are displaced from the position shown in
FIG. 11A
to that shown in FIG.
11
B. As a result, the cam portion
112
is detached from the apex of the cam portion
103
d
of the first lever member
103
, and the first lever member
103
receives the elastic force of the torsion coil spring to advance along the longitudinal direction of the elongated holes
103
a
and
103
b
, the abutting portion
103
c
advancing into the rotation path of the cancel protrusion
114
. Further, with the rotation in the direction of the arrow B of the operating lever
107
, switching operation is effected on a contact (not shown), and the right-hand turn lamp blinks.
In the right-hand turn state shown in
FIG. 11B
, when the steering wheel is turned in the opposite direction (the direction of the arrow in the drawing), the cancel protrusion
114
abuts the abutting portion
103
c
of the first lever member
103
during the return operation. As a result, the first lever member
103
rotates clockwise as seen in the drawing around the guide shaft
101
, and the torque is transmitted from the second elongated hole
103
b
to a second lever member
104
through a connection pin
104
a
, and the second lever member
104
rotates clockwise around the support shaft
102
, so that the second opening
104
C of the second lever member
104
is rotated and displaced upward as seen in the drawing. As a result, the periphery of the second opening
104
C upwardly pressurizes the

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