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BACKGROUND OF THE INVENTION
This invention relates to a lever switch in which a conductive material
held at the end of a lever is moved into and out of engagement of first
and second stationary contacts.
There is available a lever switch such as a wiper and washer switch
assembly installed on the steering column of an automobile. In the
assembly, the wiper switch takes a plurality of positions with its lever
swung vertically, and the washer switch is turned on and off with the same
lever pushed forwardly and backwardly.
In FIGS. 5 through 7, reference numeral 1 designates a casing mounted on a
steering column (not shown). The casing 1 has a cylindrical portion 2 at
the center into which a steering shaft is inserted. Reference numeral 3
designates a wiper switch which comprises: a plurality of stationary
contacts 5 provided on an insulator 4; and a movable contact 8 which is
held in a contact holder 6 through a spring 7 so that it is slid on the
upper surfaces of the stationary contacts 5. Reference numeral 9
designates a bracket which has a shaft 9a. The shaft 9a is inserted into a
hole la formed in the casing 1, so that the bracket is swung vertically or
in the direction of the arrow A and in the opposite direction. Reference
numeral 10 designates a lever having a pin 10a in the base portion. The
pin 10a is engaged with a hole formed in the bracket 9, so that the lever
10 is swung forwardly and backwardly, or in the direction of the arrow B
and in the opposite direction. Reference numeral 11 designates a washer
switch provided in the casing 1. The washer switch 11 comprises: a
stationary contact 12 provided on the insulator 4; a movable contact piece
14 made of a leaf spring one end portion of which is secured to the
insulator 4 with a rivet 13; and a movable contact 15 which is provided on
the other end portion of the movable contact piece 14 so that it is
brought into and out of engagement with the stationary contact 12. The end
portion of the lever 10 is engaged with a fork-shaped engaging portion 6a
formed on the top of the contact holder 6. Therefore, as the lever 10
together with the bracket 9 is turned in the direction of the arrow A, the
contact holder 6 is slid so that the wiper switch 3 is set to positions
OFF, INT, LO and HI. A rod 16 is connected to the lever 10 at the middle
in correspondence to the movable contact piece 14, and a push piece 18 is
coupled through a spring 17 to the end of the lever 10. The push piece 18
is pushed against a stepping recess 19 formed in the casing 1. More
specifically, when, at each position of the wiper switch, the lever 10 is
turned in the direction of the arrow B to slide the push piece 18 from the
original position 19a to the action position 19b of the stepping recess
19, the rod 16 of the lever 10 pushes the movable contact piece 14, so
that the movable contact 15 is brought into contact with the stationary
contact 12; that is, the washer switch 11 is turned on. When, under this
condition, the lever 10 is turned in the direction opposite to the
direction of the arrow B, the movable contact piece 14 is restored by its
own elastic force, so that the movable contact 15 is disengaged from the
stationary contact 12; that is, the washer switch 11 is turned off.
The conventional washer switch 11 thus constructed suffers from the
following difficulties:
(1) In order to form the washer switch, it is necessary to use a number of
components such as the stationary contact 12, the rivet 13, the movable
contact piece 14, the movable contact 15, and the rod 16.
(2) The washer switch is unavoidably bulky as a whole. In order to turn on
the washer switch, first the rod 16 is lowered until it contacts the
movable contact piece 14, and then the rod 16 is further lowered to
deflect the movable contact piece 14, as a result of which the movable
contact 15 is brought into contact with the stationary contact 12. Hence,
the stroke of the rod 16; that is, the stroke of the lever 10 is
relatively large. Because of this large stroke, the washer switch is
unavoidably bulky.
(3) Whenever the washer switch is turned on, a great depressing force is
applied to the movable contact piece to bend the latter, so that the
movable contact piece is liable to be deteriorated quickly. In addition,
whenever the switch is turned on, the movable contact 15 is struck against
the stationary contact 12, so that these contacts 12 and 15 are also
liable to be deteriorated quickly.
(4) Whenever the washer switch is turned on, the contacts 12 and 15 produce
a strike sound.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of this invention is to provide a lever
switch which is small in the number of components and accordingly small in
size, and in which the deterioration of the components is suppressed, and,
when it is turned on, the production of the strike sound is decreased as
much as possible.
The foregoing object of the invention has been achieved by the provision of
a lever switch which, according to the invention, comprises: first and
second stationary contacts mounted on a casing; a lever mounted rotatably
on the casing; and a conductive member including an elastic coil, and
contacts which are formed by using both end portions of the coil, the
lever being operated so as to move said contacts of said conductive member
into and out of engagement with said first and second stationary contacts.
The lever switch of the invention, being made up of the first and second
stationary contacts and the conductive member, is smaller in the number of
components than the conventional lever switch. Furthermore, since the
contacts of the conductive member are moved directly into and out of
engagement with the first and second stationary contacts, the stroke of
the lever is shorter than in the conventional lever switch, thus allowing
a reduction in size of the lever switch. Since the coil forming the
conductive member is elastic, the contacts of the conductive members are
elastically brought into contact with the first and second stationary
contacts. Hence, the deterioration of the conductive member and the first
and second stationary contacts can be suppressed which is due to the
striking of the contacts of the conductive member hard against the first
and second stationary contacts, and, when the switch is turned on, the
production of a strike sound is substantially prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional bottom view showing a part of the wiper and washer
switch assembly according to the invention;
FIG. 2 is a front view, with parts cut away, showing the wiper and washer
switch assembly;
FIG. 3 is a cross sectional view of a wiper switch in the assembly; and,
FIG. 4 is a perspective view of a washer switch in the assembly;
FIG. 5 is a sectional bottom view showing a part of the conventional wiper
and washer switch assembly;
FIG. 6 is a front view of the conventional wiper and washer switch
assembly; and
FIG. 7 is a sectional view for a description of the relationships between a
movable contact piece and a rod of the conventional wiper.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
One example of a wiper and washer switch to which the technical concept of
the invention is applied, constituting one embodiment of the invention,
will be described with reference to FIGS. 1 through 4.
In FIGS. 1 and 2, reference numeral 21 designates a casing mounted on a
steering column (not shown). An insulator 22 is engaged with an opening
formed in the lower surface of the casing 21. The casing has a cylindrical
portion 23 at the center into which a steering shaft (not shown) is
inserted. Reference numeral 24 designates a bracket having an
accommodating chamber 24a opened downwardly. Shafts 24b and 24b are
protruded from the front and rear surfaces of the bracket respectively,
and are engaged with holes 21a and 21a formed in the casing 21
respectively so that the bracket can be turned in the direction of the
arrow A and in the opposite direction. Reference numeral 25 designates a
lever whose one end portion is inserted in the accommodating chamber 24a.
The lever has a pin 26 protruded from its base. The pin 26 is supported by
the bracket 24 so that the lever can be turn in the direction of the arrow
B perpendicular to the direction of the arrow A and in the opposite
direction. When the lever 25 together with the bracket 24 is turned in the
direction of the arrow A or in the opposite direction, the lever is moved
stepwise by a stepping mechanism (not shown).
Further in FIGS. 1 and 2, reference numeral 27 designates a first switch of
slide type, namely, a wiper switch mounted on the casing. The wiper switch
27 comprises: a plurality of stationary contacts, for instance five
stationary contacts 28a through 28e, mounted on the insulator 22; and a
movable contact piece 29 mounted on the end of the bracket 24. The movable
contact piece 29 is U-shaped as shown in FIG. 3, and has elongated holes
29b and 29b formed in its risers 29a and 29a. The elongated holes 29b are
engaged with protrusions 30 and 30 formed on both sides of the bracket 24,
respectively, so that the movable contact piece is movable. A spring 31 is
inserted in a recess 24c formed in the bracket 24, so that the movable
contact piece 29 is pushed against two of the stationary contacts 28a
through 28e. Reference numeral 32 designates a second switch of confront
type, namely, a washer switch. The washer switch 32 comprises: first and
second arcuate contacts 33 and 34 which are coaxially mounted on the
insulator 22; and a conductive member 35 which is moved into and out of
engagement with those first and second arcuate contacts 33 and 34. The
conductive member 35, as shown in FIG. 4, is a coil of spring steel which
comprises: a coil body 35a having both end portions which are extended;
and two contacts 35b and 35c are formed by arcuately bending both tip
portions of extended end portions of the coil body 35a. The coil body 35a
is supported by engaging means 36 consisting of two engaging pawls
protruded from the lever 25.
A circular recess 37 is formed in the end portion of the lever 25. A push
piece 39 is inserted through a spring 38 into the circular recess 37 in
such a manner that it is pushed against a stepping recess 40 formed in the
bracket 24, thus forming the aforementioned stepping mechanism.
The operation of the lever switch thus constructed will be described.
First, the wiper switch 27 will be described with reference to FIGS. 2 and
3. When the wiper switch is positioned at "OFF", the movable contact piece
29 is in contact with the stationary contacts 28a and 28b. As the wiper
switch 27 is positioned at "INT", "LO" and "HI" successively with the
lever 25 turned downwardly or in the direction of the arrow A, the movable
contact piece 29 is slid on the stationary contacts 28a through 28e, so
that the stationary contacts 28b and 28c, 28c and 28d, 28d and 28d are
short-circuited successively.
Now, the washer switch 32 will be described with reference to FIGS. 1 and
4. Normally, the push piece 39 of the lever 25 is abutted against the
original position of the stepping recess; that is, the conductive member
35 is in disengagement from the first and second stationary arcuate
contacts 33 and 34; that is, the washer switch is held turned off. When
the lever 25 is turned forwardly, or in the direction of the arrow B, the
push piece 39 is moved from the original position 40a toward the action
position 40b, while the conductive member 35 is moved backwardly. When the
lever 25 is further turned in the same direction until the push piece 39
comes to the action position 40b of the stepping recess 40, the contacts
35b and 35c of the conductive member 35 are brought into contact with the
first and second stationary arcuate contacts 33 and 34, respectively; that
is, the first and second stationary arcuate contacts 33 and 34 are
short-circuited with the conductive member 35, so that the washer switch
32 is turned on (cf. FIG. 4).
The lever switch thus constructed has the following effects or merits:
As was described above, the washer switch 32 is made up of the first and
second stationary contacts 33 and 34 mounted on the insulator 22; and the
conductive member 35 which is mounted on the end of the lever 25 so as to
be moved into and out of engagement with the stationary contacts 33 and
34. Hence, the washer switch 32 is smaller in the number of components and
accordingly lower in manufacturing cost than the conventional one.
Furthermore, since the conductive member 35 comprises the elastic coil
body 35a, and the contacts 35b and 35c which are formed by bending both
end portions of the coil body 35a in such a manner that the contacts 35b
and 35c are brought directly in contact with the stationary contacts 33
and 34, respectively. Therefore, when the washer switch is turned on, the
stroke of the lever 25 is shorter than in the case of the conventional
lever switch. In addition, since the coil body 35a of the conductive
member 35 is elastic, when the lever 25 is turned the contacts 35b and 35c
of the conductive member 35 are elastically brought into contact with the
stationary contacts 33 and 34. This construction eliminates the difficulty
that otherwise the conductive member 35 and the stationary contacts 33 and
34 are deteriorated being struck hard against one another or being greatly
bent. In this case, the production of a strike sound is substantially
prevented.
In the conventional wiper and washer switch assembly shown in FIGS. 5
through 7, the wiper switch 3 is of slide type. In order to improve the
sliding characteristic of the wiper switch 3, grease is applied to the
movable contact 8. If the grease is splashed to the stationary contact 12
or the movable contact 15 of the washer switch 11, then the following
difficulty may be involved: That is, even if the movable contact 15 is
pushed against the stationary contact 12, because of the grease the former
15 may not be electrically connected to the latter 12; that is, the switch
may not be turned on. On the other hand, in the lever switch of the
invention, when the contacts 35b and 35c of the conductive member 35 are
brought into contact with the stationary contacts 33 and 34, the
elasticity of the coil body 35a causes the contacts 35b and 35c to slide
away from each other; that is, the contacts 35b and 35c perform a
so-called "wiping action". Hence, even when the grease applied to the
wiper switch 27 of slide type is splashed to the stationary contacts 33
and 34 of the washer switch 32 of confront type, or to the contacts 35b
and 35c of the conductive member 35, the wiping action removes the grease,
whereby the contacts 35b and 35c of the conductive member 35 are
electrically sufficiently connected to the stationary contacts 33 and 34;
that is, the switch is positively turned on.
In the conventional lever switch, when the lever 10 is turned in the
direction of the arrow B which is set at any one of the positions OFF,
INT, LO and HI as shown in FIG. 7, it is necessary for the rod 16 to
depress the movable contact piece 14 of the washer switch 11 thereby to
bring the movable contact 15 into contact with the stationary contact 12.
In this operation, the lever 10 is swung a predetermined stroke so that
the push piece 18 is moved from the original position 19a to the action
position 19b in the stepping recess 19. Accordingly, in swinging the lever
10; that is, in moving the rod 16, the stroke is so determined that, with
the lever 10 set at the position OFF, the movable contact 15 formed on the
movable contact piece 14 is positively brought into contact with the
stationary contact 12. Accordingly, when compared with the stroke of the
rod in an ordinary switch of confront type in which the rod is adapted to
depress the middle of the movable contact piece, the stroke of the rod 16
is necessarily long, thus making the lever switch bulky. In addition, as
the lever 10 is shifted to the positions INT, LO and HI in the stated
order, the force applied to the movable contact piece 14 through the rod
16 is increased more than required, so that the movable contact piece 14
is deformed increasingly more than required, thus being deteriorated
quickly. On the other hand, in the lever switch of the invention, with the
lever 25 set at any one of the positions OFF, INT, LO and HI, the distance
between the contacts 35b and 35c of the conductive member 35 and the
stationary contacts 33 and 34 is maintained unchanged. Accordingly, the
stroke for swinging the lever 25 can be set to a minimum value, and the
lever switch can be miniaturized as much. For the same reason, the
conductive member 33 is not bent more than required, with the result that
the deterioration is suppressed more.
In the above-described embodiment, the technical concept of the invention
is applied to a wiper and washer switch assembly for an automobile;
however, the invention is not limited thereto or thereby. That is, the
technical concept of the invention is applicable to all lever switches in
which the lever is turned only in predetermined directions (for instance
in the direction of the arrow B and in the opposite direction, and the
contact of the conductive member is brought into contact with first and
second stationary contacts.
In the lever switch according to the invention, the conductive member which
is the elastic coil with both end portions formed into the contacts is
mounted on the end of the lever, and the lever is operated so as to bring
the contacts of the coil into contact with the first and second stationary
contacts. Owing to this construction, the lever switch is smaller in the
number of components, and small in size. Furthermore, for the same reason,
the deterioration of the components is suppressed, and, when the switch is
turned on, a strike sound is scarcely produced. These effects should be
highly appreciated.
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