192 clutches and power-stop control – Transmission and brake – Motor vehicle
Reexamination Certificate
2000-01-11
2001-10-30
Herrmann, Allan D. (Department: 3682)
192 clutches and power-stop control
Transmission and brake
Motor vehicle
C192S220700
Reexamination Certificate
active
06308814
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to shift control devices for automatic transmissions for automotive vehicles and more particularly to a parking lock mechanism for a gate type automatic transmission shift control device.
2. Description of the Related Art
A parking lock mechanism in an automatic transmission shift control device prevents a shift lever from being shifted from a parking position into any other gear positions unless a brake pedal is depressed after start of an engine in order to prevent sudden start of an automotive vehicle. More specifically, the parking lock mechanism includes a lock lever which is swingable when actuated by an actuator in responsive to depression of the brake pedal. When the shift lever is in the parking position, the lock lever prevents a position pin in contact with a detent cutout portion from being pushed down for thereby preventing the shift lever from being shifted from the parking position into any other gear positions. In such a shift control device, the shift lever moves along a linear shift groove so as to be shifted into one of gear positions of P (Parking), R (Reverse), N (Neutral), D (Drive) and L (Low).
A gate type automatic transmission shift control device in which a shift lever moves along a gate opening having a crank-like shape, is disclosed for example in Japanese Patent Provisional Publication No. 8-334167. In this shift control device, a lock lever is swingably supported on a housing which is formed with a gate opening. The shift lever has a radial projection which is capable of abutting upon the lock lever. When the shift lever is shifted into a parking (P) position, the projection is caused to abut upon the lock lever to disable shift of the shift lever from the parking position into a parking lock released position. In this instance, the lock lever in contact with the projection of the shift lever is urged against the side wall of the housing, so that the side wall serves as a bearing or support member.
SUMMARY OF THE INVENTION
However, in such a shift control device in which the projection of the shift lever urges the lock lever against the side wall of the housing so that the side wall serves as a bearing or support member, the side wall of the housing is necessarily required to have a large strength. The housing has been designed on the structure, material, etc. so as to meet the above requirement, resulting in that the housing is large-sized in the widthwise direction and complicated in shape. The prior art gate type automatic transmission shift control device thus encounters a problem that it is costly.
It is an object of the present invention to provide a parking lock mechanism for a gate type automatic transmission shift control device which is free from the above noted problem inherent in the prior art shift control device.
It is a further object of the present invention to provide a parking lock mechanism for a gate type automatic transmission shift control device of the foregoing character which does not require the side wall of the housing be strong enough as to serve as a bearing or support member but can eliminate the requirements otherwise necessitated in design of the housing with respect to the structure, material, etc. thereof.
It is a further object of the present invention to provide a gate type automatic transmission shift control device which is lower in cost as compared with a comparable prior art device.
To achieve the above objects, the present invention provides a parking lock mechanism for a gate type shift control device for an automotive automatic transmission. The shift control device includes a housing having a gate opening and a vertical side wall, and a shift lever shiftable along the gate opening into a plurality of gear positions including a parking position and a parking lock released position. The parking lock mechanism comprises a pair of first projections formed on an inner surface of a side wall of the housing, the first projections being vertically spaced from each other and located adjacent a portion of the gate opening corresponding to the parking lock released position of the shift lever, a second projection formed on the shift lever in a way as to protrude radially therefrom and capable of passing through an interval between the first projections when the shift lever is shifted from the parking position into any other gear positions, a lock lever mounted on the inner surface of the side wall in a way as to be swingable along the inner surface and between a first position where it abuts upon the first projections to prevent shift of the shift lever from the parking position to a parking lock released position and a second position where it is spaced away from the first projections to allow the second projection to pass through the interval between the first projections and thereby allow shift of the shift lever from the parking position to the parking lock released position, and an actuator for actuating the lock lever to move into the second position when energized in response to depression of a brake pedal and allowing the lock lever to move into the first position when deenergized.
Accordingly, when the shift lever is in a parking position, a gearshift operation for shifting the shift lever from a parking position to any other gear position without depressing the brake pedal is obstructed since the lock lever is abutted upon or in contact with the pair of upper and lower projections on the side surface of the housing. In this instance, the lock lever is supported by both of the upper and lower projections, thus not causing any large load to be applied to the support portion of the lock lever whilst not subjecting the side wall to any large load in the thickness direction thereof.
REFERENCES:
patent: 5695029 (1997-12-01), Yokoyama et al.
patent: 5980423 (1999-11-01), Suzuki et al.
patent: 6009769 (2000-01-01), Ikegami
patent: 8-334167 (1996-12-01), None
patent: 8-338513 (1996-12-01), None
Foley & Lardner
Fuji Kiko Co. Ltd.
Herrmann Allan D.
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