Electricity: circuit makers and breakers – Special application – Turn indicator type switches
Reexamination Certificate
2002-10-17
2004-01-13
Enad, Elvin (Department: 2832)
Electricity: circuit makers and breakers
Special application
Turn indicator type switches
C200S061350
Reexamination Certificate
active
06677543
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, an external force preventing the automatic restoring is applied to the operating lever.
2. Description of 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 of 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 pressurizing 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 returning direction which is a direction opposite to the indicated direction, with the operating lever rotated to the right or left direction indicating position.
The description will be made of drawings showing such a cancel mechanism according to the prior art.
FIG. 6
is a cross sectional view schematically showing the construction of the turn signal switch device;
FIG. 7
is a front view of a movable member provided in the turn signal switch device; and
FIGS. 8A and 8B
are schematic diagrams illustrating the operation of a cancel mechanism provided in the turn signal switch device.
With reference to
FIGS. 6
to
8
, the description will be made of the turn signal switch device according to the prior art. A housing
100
is substantially box-shaped, made of insulating resin, and is secured to a column (not shown), which is a stator member of a steering device, and the like. On the bottom surface of the housing
100
, a guide shaft
101
and a support shaft
102
are formed to protrude at a predetermined interval, and at the end of the bottom surface, a cylindrical protrusion
106
is provided. Also, 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 second lever member
104
is made of insulating resin; has an outside shape being substantially rectangular; has a first opening
104
b
and a second opening
104
c
; between these two openings, there is provided a shaft hole
104
d
; and at the outer end of the first opening
104
b
, a connection pin
104
a
is formed. A shaft hole
104
d
of the second lever member is rotatably fitted in a support shaft
102
provided in the bottom surface of the housing
100
.
The first lever member
103
is made of insulating resin, is square bar-shaped, and has a first elongated hole
103
a
and a second elongated hole
103
b
which are arranged in a line in the longitudinal direction. Further, at the front and rear ends of the first lever member
103
in the longitudinal direction, there are provided an abutting portion
103
c
and a cam
103
d
respectively, the cross sectional configuration of the cam
103
d
being semi-circular. The first elongated hole
103
a
of the first lever member
103
is slidably fitted in the guide shaft
101
formed on the bottom surface of the housing
100
, and the second elongated hole
103
b
is slidably fitted in a connection pin
104
a
provided in the second lever member
104
to connect the first lever member
103
with the second lever member
104
.
In a torsion coil spring
105
, wire formed of elastic material is wound several turns, both ends are left in a straight line state, the wound portion is fitted in and fixed to a protrusion
106
of the housing
100
, one of the straight line-shaped portions at both ends is fixed to the end of the bottom surface of the housing
100
, and the other is engaged with the first lever member, whereby the first lever member
103
is adapted to be elastically biased in the direction that goes away from the second lever member
104
in the longitudinal direction of the first lever member
103
.
A holder
110
is a structure made of insulating resin, is mounted within the housing
100
, has support shafts
108
at both ends, and is provided with a cylinder
110
a
protruding,on the front side. Inside the cylinder
110
a
, 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
of the housing
100
by a spring (not shown).
An operating lever
107
is made of insulating resin, is substantially cylindrical, the base end is fitted in support shafts
108
at both ends of the holder
110
, and is supported by the housing
100
so as to be rotatable together with the holder
110
in the direction indicated by the arrow a or b.
A movable member
115
is constructed such that, at the center of a rectangular plate member made of insulating resin, there is integrally provided a cylinder portion
115
a
vertically to the plate member; at the top end, there are provided a pair of engagement claws
115
b
; the wound portion of a return spring
116
wound is wound around the cylinder portion
115
a
; and both arms of the return spring
116
are restrained by a pair of engagement claws
115
b
and
115
b
. Inside the cylinder portion
115
a
, a cylinder
110
a
of the holder
110
is rotatably housed. The both arms of the return spring
116
are restrained by a pair of engagement claws
115
b
and
115
b
and engaged with the holder
110
, whereby the movable member
115
is constantly biased toward a predetermined stable position with respect to the holder
110
. Therefore, normally the rotation of the operating lever
107
rotates integrally the movable member
115
together with the holder
110
. Further, the movable member
115
is provided with a cam
112
having a semi-circular cross sectional configuration and a receiving portion
113
, and the cam
112
is opposed to the cam
103
d
of the first lever member
103
, the receiving portion
113
protruding in the second opening
104
c
of the second lever member
104
.
Next, the description will be made of an operation of 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. 8A
, the cam
112
of the movable member
115
on the operating lever
107
side and the cam
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 member
103
is positioned outside the rotation path of a cancel protrusion
114
rotating with the steering wheel; even if the steering wheel is turned in this state, 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 in
FIG. 6
, 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
Ito Takehiko
Takahashi Atsuo
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Enad Elvin
Klaus Lisa
LandOfFree
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