Machine element or mechanism – Gearing – Interchangeably locked
Reexamination Certificate
2000-06-29
2002-06-11
Herrmann, Allan D. (Department: 3682)
Machine element or mechanism
Gearing
Interchangeably locked
C074S378000, C074S473100, C074S473270, C192S051000, C192S09300C, C440S075000
Reexamination Certificate
active
06401560
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a shift mechanism of an outboard engine.
2. Description of the Related Art
A conventional outboard engine has a shift mechanism which is remotely-operable to change the direction of rotation of a propeller shaft between “forward” and “reverse” passing through a “neutral” state in the process. To enable such a change-over of direction of rotation, the propeller shaft has a push rod incorporated therein. The push rod is moved back and forth to bring a shift dog into and out of engagement with the propeller shaft. This arrangement is generally known as a “shift-in and shift-out” structure. A shift cam is typically used as means for effecting the back-and-forth movement of the push rod.
The shift cam has a cam profile which is defined by three curved recesses that are smoothly connected one to another. These three recesses correspond to three shift positions, i.e., the “forward”, “reverse” and “neutral” states, of the shift mechanism. The above-mentioned push rod is normally spring-biased towards the cam, so as to rest in one of the three recesses, thus selecting one of the three shift positions.
There are two types, of the shift cam: a vertically-movable shift cam which moves up and down to bring different recesses into engagement with the push rod; and a rotational shift cam which rotates within a horizontal plane. The rotational shift cam imparts to the operator a better feel of manipulation and is used mainly for large-sized outboard engines.
The shift cam is supported by a shift cam support portion which is disposed in, and formed integrally with, a gear case, regardless of the type of the shift cam.
The rotational shift cam and the vertically-movable shift cam have different structures and, hence, require different designs of the shift cam supporting structure. This means that one design of the gear case cannot be used commonly both for the rotational shift cam and the vertically-movable shift cam, due to the difference of the design of the shift cam supporting structure which is formed integrally with the gear case. Thus, manufacturers are obliged to prepare two types of gear case of different designs. This in turn requires troublesome work for the administration of the gear cases in the production process.
For instance, the following problems are encountered due to the difference between the two types of the shift cam. A vertically-movable shift cam is generally provided with a link mechanism in an engine room covered by an engine cover. It may be impossible to find space for accommodating such a link mechanism within the engine room, due to, for example, a change in the design specifications of the outboard engine. One solution to this problem could be to replace the vertically-movable shift cam with a rotational shift cam which does not require any link mechanism such as that used for the vertically-movable shift cam. This solution, however, imposes additional cost due to the necessity for a gear case which is designed exclusively for the rotary shift cam.
In general, the shift cam supporting portion is formed on the innermost portion of a gear case. This makes it difficult to mount and demount the shift cam.
OBJECTS AND SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide a shift mechanism of an outboard engine which permits the use of a single type of gear case either with a vertically-movable shift cam or a rotational shift cam.
To this end, according to the present invention, there is provided a shift mechanism of an outboard engine, comprising: a remotely-operable shift cam for effecting change-over of the direction of rotation of a propeller shaft within a gear case; and a shift cam support member disposed in the gear case and detachably secured to the gear case and supporting the shift cam.
The shift cam support member may be a forward gear bearing housing for holding a bearing which supports a forward driven gear.
Alternatively, the shift cam support member may be a shift cam housing which is a member formed separately from and detachably secured to the gear case.
The shift mechanism may further comprise a detent mechanism provided on the shift cam support member.
The shift mechanism may also further comprise a bearing which is provided in the shift cam housing and which supports a shift rod for rotating the shift cam.
Preferably, the shift cam mechanism has been assembled by inserting the shift cam housing together with the shift can mounted therein, forwardly into the gear case and detachably securing the shift cam housing to the gear case.
The above and other objects, features and advantages of the present invention will become clear from the following description of a preferred embodiment with reference to the accompanying drawings.
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patent: 2718792 (1955-09-01), Kiekhaefer
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patent: 3919964 (1975-11-01), Hagen
patent: 4223773 (1980-09-01), Croisant et al.
patent: 4527441 (1985-07-01), Nakahama
patent: 4579204 (1986-04-01), Iio
patent: 5006084 (1991-04-01), Handa
patent: 5059144 (1991-10-01), Onoue
patent: 09216600 (1997-08-01), None
patent: 10-114299 (1998-05-01), None
patent: 11165695 (1999-06-01), None
Herrmann Allan D.
Morrison Law Firm
Suzuki Motor Corporation
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