Machine element or mechanism – Control lever and linkage systems – Multiple controlled elements
Reexamination Certificate
2002-06-25
2004-04-27
Bucci, David A. (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Multiple controlled elements
C074S473240, C074S473260
Reexamination Certificate
active
06725738
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a gear shift apparatus for a manual transmission for use in a vehicle such as an automotive vehicle, and more particularly, to a gear shift apparatus for a manual transmission which comprises a mis-shift preventing mechanism for preventing a driver from erroneously operating the transmission from a forward gear stage to a reverse gear stage during forward running of the vehicle.
2. Description of the Prior Art
Conventionally, as a gear shift apparatus of the type mentioned above, one illustrated in
FIGS. 1A-1D
is known. This manual transmission has a shift pattern (for example, see
FIG. 3
) in which forward first through sixth gear stage positions are disposed at respective ends of three parallel lines, and an additional reverse gear stage position defined outside the fifth or sixth gear stage position in a select direction indicated in FIG.
3
. The gear shift apparatus
80
also comprises an interlock
81
connected to a transmission lever (not shown) through a cable for pivotal movement associated with a selecting manipulation of the transmission lever in the select direction to perform a gear shift operation; and a solenoid (not shown) for restricting the pivotal movement of the interlock
81
to prevent a miss shift manipulation of the transmission lever from a forward gear stage position to the reverse gear stage position during forward running of the vehicle.
The interlock
81
is pivotable about a vertical axis to take the following four select positions associated with a selecting manipulation of the transmission lever. Specifically, the interlock
81
is pivoted to a first-second speed select position (a position indicated by solid lines in
FIG. 1D
) at which the first-speed or second-speed gear stage can be selected; a neutral position (a position indicated in
FIG. 1A
) at which the third-speed or fourth-speed gear stage can be selected; a fifth-sixth speed select position (a position indicated by solid lines in
FIG. 1B
) at which the fifth-speed or sixth-speed gear stage can be selected; and a reverse select position (a position indicated in
FIG. 1C
) at which the reverse gear stage can be selected.
The interlock
81
also comprises two cams
82
,
83
which are spaced apart from each other. The cam
83
has an inclined cam face
83
a
which opposes the cam
82
.
The solenoid is electrically connected to a controller, not shown, which turns the solenoid ON when the vehicle speed is equal to or higher than a predetermined vehicle speed and OFF when the vehicle speed is lower than the predetermined vehicle speed. A pin
84
is coupled to a leading end of a plunger of the solenoid, and is urged upward by a return spring, not shown. This causes the pin
84
to move in the vertical direction as the solenoid is turned ON/OFF (energized/deenergized), and holds the pin
84
at a lower restraint position (see
FIGS. 1A
,
1
B) when the solenoid is ON and at an upper release position (see
FIG. 1C
) when the solenoid is OFF. As illustrated in
FIG. 1A
, the pin
84
is positioned between both cams
82
,
83
when the pin
84
is held at the restraint position with the interlock
81
remaining at the neutral position.
In the gear shift apparatus
80
, the interlock
81
operates associated with a selecting manipulation of the transmission lever, as described below. Specifically, when the vehicle speed is lower than the predetermined vehicle speed, the pin
84
is held at the release position, thereby permitting the interlock
81
to smoothly pivot to any of the aforementioned four select positions associated with a selecting manipulation of the transmission lever, without hitting the pin
84
.
On the other hand, when the vehicle speed is equal to or higher than the predetermined vehicle speed, the pin
84
is held at the restraint position, in which case the cam
82
abuts to the pin
84
as illustrated in
FIG. 1B
when the interlock
81
is pivotally moved from the neutral position to the fifth-sixth speed select position, associated with a selecting manipulation of the transmission lever. As a result, the interlock
81
is blocked from pivoting to the reverse select position illustrated in
FIG. 1C
, thereby preventing a miss shift manipulation to the reverse gear stage position during forward running.
As the interlock
81
is pivotally moved from the neutral position to the first-second speed select position, the cam
83
abuts to the pin
84
as illustrated in
FIG. 1D
to forcedly push up the pin
84
through the cam face
83
a
. Consequently, the interlock
81
is permitted to pivotally move to the first-second speed select position, with the result that a selecting manipulation (shifting manipulation) can be made to the first-speed or second-speed gear stage by the transmission lever.
Further, when the pin
84
is erroneously held at the restraint position due to the stuck solenoid, in spite of the vehicle speed lower than the predetermined vehicle speed, the pin
84
is also pushed up forcedly by the cam face
83
a
by a pivotal movement of the interlock
81
from the neutral position to the first-second speed select position, associated with a selecting manipulation of the transmission lever. This can forcedly release an erroneous gear shift disabled state, in which the transmission lever cannot be shifted to the reverse gear stage position, due to a stuck electromagnetic actuator or the like, thus permitting a gear shift manipulation to the reverse gear stage position.
In the conventional gear shift apparatus
80
, a horizontal force (moment) generated by a pivotal movement of the interlock
81
about the vertical axis is converted to a vertical force for pushing up the pin
84
through the inclined cam face
83
a
, when the pin
84
is pushed up, in order to forcedly release the gear shift preventing state. Thus, due to an extremely small vertical component force relative to the horizontal force acting on the pin
84
from the cam face
83
a
, a large force is required for manipulating the transmission lever for selection, when the gear shift preventing state is forcedly released, resulting in a problem that the driver has a bad manipulation feeling.
OBJECT AND SUMMARY OF THE INVENTION
The present invention has been made to solve the foregoing problem, and it is an object of the invention to provide a gear shift apparatus for a manual transmission which utilizes an actuator to prevent a miss shift manipulation from a forward gear stage to a reverse gear stage, wherein the gear shift apparatus allows a driver to perform a selecting manipulation with a small force for forcedly releasing a miss shift preventing state and therefore have a light gear shift feeling.
To achieve the above object, the present invention provides a gear shift apparatus for a manual transmission having a shift pattern comprised of a plurality of forward select positions for selecting a plurality of forward transmission gear stages, respectively, and a reverse select position arranged outside said plurality of forward select positions for selecting a reverse transmission gear stage, for selecting one of said plurality of forward transmission gear stages and said reverse transmission gear stage through a selecting manipulation and a shifting manipulation.
The gear shift apparatus of the present invention is characterized by comprising a select cam responsive to the selecting manipulation to pivotally move to a plurality of forward positions and a reverse position corresponding to the plurality of forward select positions and the reverse select position, respectively, to permit a selection by the shift manipulation from the plurality of forward transmission gear stages and the reverse transmission gear stage; a restraint cam pivotally movable between a prohibiting position at which the restraint cam comes into engagement with the select cam to prohibit the select cam from pivotally moving to the reverse position, and a permitting position at which the restraint cam is retraced from the prohib
Hosoda Kazufumi
Nemoto Keiji
Okubo Kiyokazu
Onuma Yasushi
Yakou Takayuki
Bucci David A.
Hansen Colby
Westerman Hattori Daniels & Adrian LLP
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