Apparatus for returning turn indicator operating lever for vehicle

An apparatus for returning a turn indicator operating lever to the neutral position in response to the turning of a steering wheel includes engagement pieces which abut against a canceling cam rotated in response to the turning of the steering wheel for the purpose of returning the operating lever to the neutral position. The engagement pieces are disposed on the one side of a steering shaft where the operating lever is disposed. It is therefore possible for various kinds of elements such as sensors to be disposed on the other side of the steering shaft.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus for returning a turn 
indicator operating lever arranged such that the operating lever which has 
been actuated for the purpose of indicating the course of the vehicle when 
changing its advancing direction is automatically returned to the neutral 
position by turning the steering wheel in the opposite direction relative 
to the turning direction by which the course of travel is changed. 
2. Description of the Prior Art 
In the conventional apparatus of the type described above, a bracket is 
pivotally supported on a base plate in such a manner as to surround the 
periphery of a steering shaft around which a cylindrical canceling cam is 
positioned. The turn indicator operating lever is mounted on one side of 
the bracket, that is, one side of the steering shaft, and a ratchet which 
constitutes a part of the returning apparatus is provided on the other 
side of the steering shaft. The arrangement is such that, when the bracket 
is pivoted leftwardly or rightwardly by the action of the operating lever 
which is actuated for the purpose of indicating a left-turn or right-turn 
of the vehicle, a pawl of the ratchet is positioned on the locus of 
rotation of a cam projection of a canceling cam which rotates in response 
to the turning of the steering wheel, whereby, when the canceling cam is 
rotated in the opposite direction relative to the direction in which the 
lever has been actuated, the cam projection of the canceling cam presses 
against the pawl of the ratchet, thus causing the bracket and in turn the 
operating lever to be returned to the neutral position. 
The above-described conventional arrangement, however, suffers from the 
following problem. Namely, since the bracket is provided in such a manner 
as to surround the canceling cam, it is necessary for the bracket to 
possess a disadvantageously large size, which fact unfavorably leads to an 
increase in the size of the returning apparatus as a whole. 
In order to overcome the above-described disadvantage, the applicant of the 
present invention has previously proposed a device (Japanese Utility Model 
Application No. 165,187/1979) in which a bracket which pivots in response 
to the actuation of the operating lever is provided with a first gear, 
while a ratchet holder provided with a second gear which is meshed with 
the first gear is disposed pivotally and is equipped with a ratchet, and 
when the canceling cam is rotated in the same direction as the actuation 
direction of the operating lever, the ratchet acts such as to allow the 
canceling cam to rotate, while when the canceling cam is rotated in the 
opposite direction, the bracket is returned to the neutral position 
through the ratchet holder. 
This arrangement, however, has a complicated gear structure, which creates 
the new problem that labor and time are required in assembly when, for 
example, a positioning operation is conducted. Further, since the second 
gear shaft is disposed between the operating lever and the steering shaft, 
the position where the operating lever is pivotally supported is 
unfavorably separated from the steering shaft. 
Moreover, another structure has previously been proposed (U.S. Pat. No. 
3,794,785) in which an operating lever and a single ratchet are provided 
on one side of a steering shaft. This structure, however, involves the 
same problem as that of the prior art described above, that is, the 
position where the operating lever is pivotally supported is excessively 
separated from the steering shaft. 
SUMMARY OF THE INVENTION 
In view of the above-described circumstances, it is a primary object of the 
present invention to provide an apparatus for returning a turn indicator 
operating lever for a vehicle which enables a reduction in the size, 
requires no gear mechanism or the like and has a simplified structure. 
To this end, the invention provides an apparatus for returning a turn 
indicator operating lever for a vehicle to a neutral position in response 
to the turning of a steering wheel in which the operating lever is 
pivotally supported in the vicinity of a steering shaft, and a regulating 
mechanism is provided. The regulating mechanism retains the operating 
lever in either one of the first and second positions when it has been 
moved thereto from the neutral position for the purpose of indicating a 
change in the advancing direction of the vehicle and returns the operating 
lever to the neutral position when the retained state is canceled. The 
apparatus further includes a pair of engagement means provided on the one 
side about the steering shaft where the operating lever is disposed. The 
engagement means are respectively disposed on the opposite sides of the 
pivotal center of the operating lever in such a manner as to oppose a 
canceling cam which is rotated in response to the turning of the steering 
wheel. One of the engagement means is adapted to enter the locus of 
rotation of the canceling cam when the operating lever is moved to the 
first position, while the other engagement means is adapted to enter that 
locus when the operating lever is moved to the second position, whereby 
the operating lever is returned to the neutral position by means of the 
rotational force of the canceling cam rotating in response to the turning 
of the steering wheel in the opposite direction relative to the direction 
in which the operating lever has been moved. 
In a state wherein the operating lever is pivoted to either one of the 
first and second positions and one of the engagement means is thereby 
caused to enter the locus of rotation of the canceling cam, when the 
canceling cam is rotated in the same direction as that in which the 
operating lever has been pivoted, the engagement means concerned is slid 
in a direction in which it is separated from the canceling cam, thereby 
allowing the canceling cam to rotate, while when the canceling cam is 
rotated in the opposite direction, the engagement means concerned is 
engaged with the canceling cam, thus causing the operating lever to return 
to the neutral position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A first embodiment of the present invention will be described hereinunder 
with reference to FIGS. 1 to 5. 
A base plate 1 is secured to a steering column (not shown) which is mounted 
on a vehicle body. The base plate 1 is formed with a cylindrical portion 3 
for receiving a steering shaft 2. A steering wheel (not shown) is 
connected to the upper end of the steering shaft 2, and a gear box (not 
shown) is connected to the lower end of the steering shaft 2 as viewed in 
FIG. 2. 
A cylindrical canceling cam 4 is rotatably fitted on the outer periphery of 
the cylindrical portion 3. The canceling cam 4 has two cam projections 4a 
projecting from its outer periphery and further has a plurality of 
projections 4b projecting from its upper end, these projections 4b being 
engaged with the steering wheel, whereby the canceling cam 4 is rotated in 
response to the turning of the steering wheel in the same direction as the 
turning direction of the steering wheel. 
A pivotally supporting bore 5 is formed in the base plate 1 in the vicinity 
of the outer periphery of the canceling cam 4 and in parallel to the 
steering shaft 2 such that the supporting bore 5 serves as a pivotal 
center. A hollow support shaft 7 is pivotally received in the pivotally 
supporting bore 5, the support shaft 7 projecting downwardly from the 
lower surface of a bracket 6. An operating lever 8 has its distal end 
projecting outwardly of the base plate 1 and its proximal end fitted into 
a bearing recess 9 formed in the bracket 6 as well as being supported by a 
support shaft 10 which is mounted on the bracket 6. Thus, the operating 
lever 8 is pivotal about the pivotally supporting bore 5 together with the 
bracket 6 in one unit from the neutral position N shown by the solid line 
in FIG. 1, both in the direction of the arrow A and in the opposite 
direction relative thereto. The operating lever 8 is also pivotal about 
the support shaft 10 in the direction of the arrow B shown in FIG. 2 while 
rotating relative to the bracket 6, for operating a dimmer and passing 
switch (not shown). 
As shown in FIG. 2, a turn signal switch 80 is mounted on the base plate 1 
in such a manner as to face the operating lever 8. The turn signal switch 
80 is constituted by a plurality of fixed contacts 82 which are disposed 
on an insulator 81 at predetermined distances such as to oppose a movable 
contact 83. The movable contact 83 is mounted on a contact holder 84 which 
is caused by the operating lever 8 to move in a direction orthogonal to 
the longitudinal axis of the operating lever 8. 
Accordingly, as the operating lever 8 moves from the neutral position N 
shown in FIG. 1 to either the position R which indicates a right-turn of 
the vehicle or the position L which indicates a left-turn of the vehicle, 
the position of contact between the movable contact 83 and the fixed 
contacts 82 is changed, whereby it is possible to turn on turn signal 
lamps (not shown) indicating a right-turn or a left-turn of the vehicle. 
A regulating mechanism 11 is provided at the proximal end of the operating 
lever 8. The regulating mechanism 11 is adapted to return the operating 
lever 8 which has been pivoted in the direction of the arrow B to the 
neutral position N. 
Arms 12 and 12' are formed integrally on the bracket 6 in such a manner as 
to be located on both sides of the support shaft 7 in such a manner that 
the line bisecting the respective longitudinal axes of the arms 12 and 12' 
is orthogonal to the longitudinal axis of the support shaft 7 and is 
substantially orthogonal to the longitudinal axis of the bearing recess 9. 
The arms 12 and 12' have bores 12a and 12'a formed at their respective 
distal ends. Balls 13 and 13' are fitted into the respective openings of 
the bores 12 and 12'. The balls 13 and 13' are biased outwardly of the 
respective openings by means of springs 14 and 14' which are respectively 
inserted into the bores 12a and 12'a. A regulating wall 15 is provided on 
the base plate 1 in such a manner as to oppose the ball 13. The regulating 
wall 15 is constituted by first to third valley portions 15a, 15b and 15c. 
The regulating wall 15, the arm 12, the ball 13 and the spring 14 in 
combination constitute a regulating mechanism 16. 
The regulating mechanism 16 is adapted to retain the operating lever 8 at 
any one of the three positions shown in FIG. 1: namely, the neutral 
position N where the ball 13 is engaged with the first valley portion 15a 
of the regulating wall 15; the first position L which represents a 
left-turn indication and at which the ball 13 is engaged with the second 
valley portion 15b as a result of the pivoting of the operating lever 8 in 
the direction of the arrow A from the neutral position N; and the second 
position R which represents a right-turn indication and at which the ball 
13 is engaged with the third valley portion 15c as a result of the 
pivoting of the operating lever 8 in the opposite direction relative to 
the direction of the arrow A from the neutral position N. 
A valley portion 17 is provided on the base plate 1 in such a manner as to 
oppose the ball 13'. Projections 17a and 17'a are formed at both ends of 
the valley portion 17. The arrangement is such that, as the operating 
lever 8 is actuated such as to shift from the neutral position N to a 
lane-change position (a position slightly before either the first or 
second position), the ball 13' abuts against either the projection 17a or 
the projection 17'a. 
First and second mounting sections 18 and 19 are provided on the bracket 6 
symmetrically with respect to each other and with respect to the support 
shaft 7. As shown in FIG. 1, these mounting sections 18 and 19 oppose one 
half of the outer periphery of the canceling cam 4 on the side thereof 
which is closer to the supporting bore 5. In other words, the first and 
second mounting sections 18 and 19 are disposed on one side of the 
steering shaft 2 which is closer to the operating lever 8. Each of the 
first and second mounting sections 18 and 19 has two engagement shafts 20 
standing on the bracket 6 and a tubular portion 21 which is formed on the 
bracket 6 and positioned between the engagement shafts 20. 
Engagement pieces 22 and 22' which serve as cam bodies are respectively 
mounted on the first and second mounting sections 18 and 19 in such a 
manner that two engagement recesses 22a of the engagement piece 22 and two 
engagement recesses 22'a of the engagement piece 22' are respectively 
engaged with the corresponding engagement shafts 20. The central portion 
of each of the engagement pieces 22 and 22' is biased in the direction of 
the arrow C, that is, toward the canceling cam 4 by means of a compression 
coil spring 23 which is received in the corresponding tubular portion 21. 
Each of the engagement pieces 22 and 22' is received between the bracket 6 
and retainer pieces 24 which project from the respective distal ends of 
the engagement shafts 20. Arm extension 12b connects the tubular portion 
21 to the tubular arm 12. Thus, each of the engagement pieces 22 and 22' 
is movable both in the direction of the arrow C and in the opposite 
direction relative thereto. A retainer piece 21A projects from each of the 
tubular portions 21 toward the corresponding one of the engagement pieces 
22 and 22' in such a manner as to prevent the corresponding compression 
coil spring 23 from coming off the associated tubular portion 21. Each of 
the retainer pieces 21A also acts in such a manner that, when the 
corresponding one of the engagement pieces 22 and 22' moves to the 
position shown by the imaginary line in FIG. 3 and enters the space 
between the retainer piece 21A and the bracket 6, the retainer piece 21A 
prevents the engagement piece from falling off the bracket 6. 
The reference numerals 25 and 25' represent first cam surfaces which 
respectively project from the engagement pieces 22 and 22' toward the 
canceling cam 4, while the numerals 26 and 26' denote second cam surfaces 
which are respectively formed adjacent to the first cam surfaces 25 and 
25'. Each of the first cam surfaces 25 and 25' has a relatively gentle 
slant and is located on the inner side of the corresponding one of the 
engagement pieces 22 and 22', that is, on the side thereof which is closer 
to the support shaft 7 of the bracket 6, while each of the second cam 
surfaces 26 and 26' has a relatively steep slant and is located on the 
outer side of the corresponding one of the engagement pieces 22 and 22'. 
It is to be noted that the reference numeral 27 represents an optical 
signal transmitting means which is located on another half of the outer 
periphery of the canceling cam 4 which is remote from the supporting bore 
5 and is secured to the base plate 1, this means being employed for 
transmission of optical signals between the same and electronic elements, 
such as a switch, provided on the steering wheel, and the reference 
numeral 28 represents a sensor for detecting a rotation relocity of the 
steering shaft. In addition, the numeral 29 denotes a wiper operating 
lever. 
The following is a description of the operation of the above-described 
arrangement. 
When the operating lever 8 is in the neutral position N, both the 
engagement pieces 22 and 22' are positioned outside the locus of rotation 
of the cam projections 4a of the canceling cam 4. When the operating lever 
8 is pivoted in the direction of the arrow A from the neutral position N 
to the first position L which indicates a left-turn of the vehicle, the 
arm 12 on the bracket 6 is also pivoted in the direction of the arrow D as 
shown in FIG. 3, thus causing the ball 13 to move from the first valley 
portion 15a to the second valley portion 15b against the resilient force 
of the spring 14. In consequence, the operating lever 8 is retained in the 
first position L, and the turn signal switch 80 is actuated to turn on the 
turn signal lamps (not shown) which indicate a left-turn of the vehicle. 
Further, the pivoting of the bracket 6 in the direction of the arrow D 
causes also the engagement piece 22 on the first mounting section 18 to 
pivot in the direction of the arrow D. Consequently, the first and second 
cam surfaces 25 and 26 of the engagement piece 22 enter the locus of 
rotation of the cam projections 4a of the canceling cam 4. 
When, under this state, the steering wheel is turned such as to rotate the 
canceling cam 4 in the direction of the arrow E, which is the same 
direction as the direction of the arrow A in which the operating lever 8 
has been pivoted, the cam projections 4a of the canceling cam 4 slide on 
the first cam surface 25, thus causing the engagement piece 22 to retract 
against the resilient force of the spring 23 in the opposite direction 
relative to the direction of the arrow C as shown by the imaginary line in 
FIG. 3. In consequence, the operating lever 8 is retained in the first 
position L as it is. 
On the other hand, when the canceling cam 4 is rotated in the opposite 
direction relative to the direction of the arrow E by the turning of the 
steering wheel, either one of the cam projections 4a engages with the 
second cam surface 26 as shown in FIG. 4, thus causing the engagement 
piece 22 and the first mounting section 18 to pivot in the opposite 
direction relative to the direction of the arrow D. Thus, the bracket 6 
and the operating lever 8 are returned to the neutral position N. 
When the operating lever 8 is pivoted in the opposite direction relative to 
the direction of the arrow A from the neutral position N to the second 
position R, the ball 13 at the distal end of the arm 12 moves from the 
first valley portion 15a to the third valley portion 15c against the 
resilient force of the spring 14 and engages with the third valley portion 
15c. In consequence, the operating lever 8 is retained in the second 
position R, and the turn signal lamps for indicating a right-turn are 
turned on. 
At this time, the engagement piece 22' and its first and second cam 
surfaces 25' and 26' on the second mounting section 19 enter the locus of 
rotation of the cam projections 4a of the canceling cam 4. When, under 
this state, the steering wheel is turned such as to rotate the canceling 
cam 4 in the opposite direction relative to the direction of the arrow E, 
which is the same direction as that in which the operating lever 8 has 
been pivoted, the cam projections 4a slide on the first cam surface 25', 
and the canceling cam 4 continuously rotates while allowing the operating 
lever 8 to be retained in the second position R, in a manner similar to 
the above. On the other hand, when the canceling cam 4 is rotated in the 
direction of the arrow E, either one of the cam projections 4a engages 
with the second cam surface 26', thus causing the operating lever 8 to 
return to the neutral position N. 
According to the above-described embodiment, the bracket 6 which pivots 
together with the operating lever 8 in one unit is provided with the first 
and second mounting sections 18 and 19 across the support shaft 7, and the 
engagement pieces 22 and 22' are respectively mounted on the first and 
second mounting sections 18 and 19 in such a manner as to oppose one half 
of the outer periphery of the canceling cam 4 on the side thereof which is 
closer to the support shaft 7. It is therefore possible for the bracket 6 
and the regulating mechanism 16 to be disposed on one side of the base 
plate 1 in a concentrated fashion. Thus, it is advantageously possible to 
reduce the size of the apparatus in contrast to the conventional apparatus 
in which a bracket is formed such as to surround the canceling cam. 
Further, since no gear mechanism or the like is required, it is possible 
for the structure of the apparatus to be favorably simplified. 
Referring next to FIGS. 6 and 7, there is shown a second embodiment of the 
present invention. In this embodiment, a pair of engagement shafts 20 
which support the engagement piece 22 are disposed in such a manner that 
the line which bisects the respective axes of the engagement shafts 20 is 
orthogonal to the longitudinal axis of the arm 12, 12'. The engagement 
shafts 20 which support the engagement piece 22' are also disposed in a 
manner similar to the above. 
Each of the engagement pieces 22 and 22' is biased by means of a torsion 
coil spring 23A in a direction in which it abuts against the corresponding 
engagement shafts 20, that is, toward the locus of rotation of the 
canceling cam 4, in a manner similar to that of the first embodiment. 
More specifically, the torsion coil spring 23A has both its ends bent in a 
direction orthogonal to the plane of the plate 1. The bent ends 23b of the 
torsion coil spring 23A are received in bores which are respectively 
formed in the engagement pieces 22 and 22' such as to bias them in the 
direction of the arrow C. The coil portion of the torsion coil spring 23A 
is received between a cover plate 90 and a holder plate 91 both secured on 
the base plate 1. Thus, the second embodiment possesses functions which 
are similar to those of the first embodiment and yet has a reduced number 
of required elements as compared with the first embodiment. 
As will be clear from the above description, the present invention is 
arranged such that the bracket which pivots together with the operating 
lever in one unit is provided with the first and second mounting sections 
which are disposed across the pivotal center of the bracket, and the 
engagement pieces are respectively mounted on the first and second 
mounting sections in such a manner that the engagement pieces oppose one 
half of the outer periphery of the canceling cam on the side thereof which 
is closer to the pivotal center of the operating lever. It is therefore 
advantageously possible to reduce the size of the apparatus and simplify 
the structure thereof.