Marine propulsion – Screw propeller – With means effecting or facilitating movement of propulsion...
Reexamination Certificate
1999-08-30
2001-02-06
Swinehart, Ed (Department: 3612)
Marine propulsion
Screw propeller
With means effecting or facilitating movement of propulsion...
C440S06100B
Reexamination Certificate
active
06183320
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a trim and/or tilt mechanism for a marine outboard drive and more particularly to an improved trim and/or tilt mechanism that includes a hydraulic cylinder device disposed transversely offset from the center axis of the mechanism per se.
2. Description of Related Art
As an example of the marine outboard drive, generally an outboard motor has a drive unit mounted on an associated watercraft by means of a trim and/or tilt mechanism which comprises a swivel bracket and a clamping bracket. The swivel bracket carries the outboard drive unit for pivotal movement about a generally vertically extending steering axis. The clamping bracket, in turn, is affixed to the transom of an associated watercraft with a pair of horizontally spaced members and supports the swivel bracket for pivotal movement about a generally horizontally extending tilt axis.
The trim and/or tilt mechanism includes also a hydraulic cylinder assembly disposed between the swivel bracket and the clamping bracket so that the swivel bracket as well as the drive unit is tilted up or down relative to the clamping bracket and eventually to the transom of the associated watercraft. The fluid motor is, for example, a compound trim and tilt hydraulic cylinder device. An exemplary hydraulic cylinder device is shown in the U.S. Pat. No. 5,718,613.
The hydraulic cylinder device includes an outer cylinder housing, a tilt cylinder slidably supported in the outer cylinder housing, a tilt piston slidably supported in the tilt cylinder and a piston rod affixed to the tilt piston at its one end and extending outwardly from both of the tilt cylinder and the outer cylinder housing. The other end of the piston rod is pivotally connected to the swivel bracket, while the outer cylinder housing is also pivotally connected to the clamping bracket. Hydraulic fluid is contained in the cavities formed in the cylinder housing and also the tilt cylinder and pressurized selectively by a powering assembly to move the piston rod either one of the expanding direction or contracting direction.
By this selective movement of the piston rod, the drive unit can be lifted up or lowered down. If an operator of the outboard motor wishes to adjust the trim angle of the drive unit, the operator operates the hydraulic cylinder device within a trim range. During this trim range operation, the tilt cylinder acts as a trim piston and moves relatively slow but produces large force. Meanwhile, if the operator wishes to tilt up or down the drive unit, he or she operates the hydraulic cylinder device within a tilt range. In this range, the tilt piston moves and this time relatively quick but produces small force.
As described above, the mechanism will operate as a trim and tilt mechanism with this hydraulic cylinder device. Some mechanism, however, is provided with either a trim cylinder device or a tilt cylinder device. Thus, the term “tilt mechanism” will mean not only the tilt mechanism per se but also the trim and tilt mechanism and even a single trim mechanism in the broad sense hereunder wholly through this specification including claims unless depicted otherwise.
The powering assembly comprises a reversible electric motor, a reversible hydraulic pump driven by the electric motor and a fluid reservoir. In order to minimize the size of the tilt mechanism, usually the powering assembly is placed between the spaced members of the clamping bracket side by side with the hydraulic cylinder device. Since the place for the hydraulic cylinder device and the powering assembly is not so spacious, it means that the hydraulic cylinder device must be decentered transversely from the axis of the tilt mechanism. This arrangement gives rise to a problem.
That is, the lifting or lowering force exerted onto the piston rod and the outer cylinder housing affects the swivel bracket and the clamping bracket as an offset load and this offset load is likely to deform the bracket assembly. If the brackets have sufficient thickness entirely, rigidity will be enough. However, this resolution apparently increases the whole weight of the bracket assembly.
It is, therefore, a principal object of this invention to provide an improved tilt mechanism to solve the problem.
It is another object of this invention to provide a tilt mechanism that will hardly cause such a deformation in its bracket assembly without having futile weight.
SUMMARY OF THE INVENTION
In accordance with one aspect of this invention, a tilt mechanism for a marine outboard drive comprises a swivel bracket. The swivel bracket carries a drive unit for pivotal movement about a generally vertically extending steering axis. The swivel bracket has wall portions extending generally transversely at both sides of the steering axis. The tilt mechanism also includes a clamping bracket. The clamping bracket supports the swivel bracket for pivotal movement about a generally horizontally extending tilt axis. The clamping bracket has a pair of transversely spaced members adapted to be affixed to the transom of an associated watercraft. The wall portions of the swivel bracket are at least partially capable to be fitted between the spaced members. The tilt mechanism further comprises a hydraulic cylinder assembly. The hydraulic cylinder assembly is capable to expand and contract along its longitudinal axis. The hydraulic cylinder assembly has a pair of end portions. One of the end portions is pivotally connected to the swivel bracket and the other one of the end portions is pivotally connected to the clamping bracket. The hydraulic cylinder assembly is biased to one of the transversely spaced members. At least one of the wall portions and the transversely spaced members positioned nearer to the hydraulic cylinder assembly is reinforced greater than the other one of the wall portions and the transversely spaced members.
In accordance with another aspect of this invention, a tilt mechanism for a marine outboard drive comprises a swivel bracket. The swivel bracket carries a drive unit for pivotal movement about a generally vertically extending steering axis. The tilt mechanism also comprises a clamping bracket. The clamping bracket supports the swivel bracket for pivotal movement about a generally horizontally extending tilt axis. The clamping bracket has a pair of transversely spaced members adapted to be affixed to the transom of an associated watercraft. The tilt mechanism further comprises a hydraulic cylinder assembly. The hydraulic cylinder assembly is capable to expand and contract along its longitudinal axis. The hydraulic cylinder assembly has a pair of end portions. One of the end portions is pivotally connected to the swivel bracket and the other one of the end portions is pivotally connected to the clamping bracket. The hydraulic cylinder assembly is disposed between the transversely spaced members and biased to one of the transversely spaced members. Each of the transversely spaced members includes a foot section being capable to be seated at the transom of the associated watercraft. Each of the transversely spaced members also includes a standing section extending from the foot portion. The respective standing sections have bores. A pivot shaft of the other one of the end portions of the hydraulic cylinder assembly is journaled in the bores. The other one of the end portions of the hydraulic cylinder assembly is disposed on the pivot shaft at generally directly next to one of the transversely spaced members. The reminder of space on the pivot shaft is balanced with a collar.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.
REFERENCES:
patent: 5529519 (1996-06-01), Nakamura et al.
Knobbe Martens Olson & Bear LLP
Sanshin Kogyo Kabushiki Kaisha
Swinehart Ed
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