Patent Application
20090170384
1. Field of the Invention
The present invention is generally related to a system for supporting a marine propulsion device on a transom of a marine vessel and, more particularly, to a support system that allows easy access to elastomeric mounts which remain generally stationary relative to a transom of a marine vessel regardless of the trim or tilt position of the marine propulsion device.
2. Description of the Related Art
Those skilled in the art of marine propulsion systems are aware of many different methods that can be used to attach marine propulsion devices to marine vessels. In the case of outboard motors, a transom bracket is typically attached to the transom of the marine vessel and the outboard motor is pivotally attached to the transom bracket to allow the outboard motor to be steered about a generally vertical steering axis and tilted about a generally horizontal tilt or trim access. Vibration isolation mounts are typically attached to the outboard motor, normally within the structure of the outboard motor itself.
U.S. Pat. No. 1,704,303, which issued to Savage on Mar. 5, 1929, describes an outboard engine bracket. More specifically, it describes a modification of previous brackets which is inexpensive to manufacture, light in weight, and of a size to be conveniently stored when not in use.
U.S. Pat. No. 2,934,303, which issued to Conrad on Apr. 26, 1960, describes an outboard motor support block. The support block is used on mounting brackets of an outboard motor to maintain the motor at a safe angle from the rear of the boat during transporting.
U.S. Pat. No. 3,599,594, which issued to Taipale on Aug. 17, 1971, describes a sound and vibration isolating mount for an outboard motor. The mounting arrangement includes a pair of mounts secured to the propulsion unit in a vertically spaced relation approximately in alignment with the neutral or roll axis of the propulsion unit and rearwardly of or behind the driveshaft. Each mount includes a crossbar which is supported by a resilient bushing within a casing and which has ends extending outwardly from the casing transversely to the direction of motion of the propulsion unit.
U.S. Pat. No. 3,613,631, which issued to Wick et al. on Oct. 19, 1971, describes an outboard motor isolation system. The mounting arrangement includes an upper resilient mount connected to the top of the power head and a lower resilient mount positioned on each side of the lower end of the driveshaft housing. The upper and lower mounts have elastic axes which are coaxially arranged with respect to the torque roll axis of the propulsion unit.
U.S. Pat. No. 3,750,615, which issued to Haft et al. on Aug. 7, 1973, describes an outboard motor noise isolation system. It comprises a propulsion unit including a driveshaft housing rigidly connected to and supporting a power head, a gear case rigidly connected to the bottom of the housing, a shell extending in circular relation to the housing upwardly from the gear case, and resilient means including a wall extending between the housing and the shell adjacent to the bottom of the shell for locating the shell in spaced encircling relation to the housing and for enabling retention of water in the space above the wall and between the shell of the housing.
U.S. Pat. No. 3,884,174, which issued to Larsen on May 20, 1975, describes a marine noise and vibration isolation system. First and second noise and vibration isolating mounts extend between upper forwardly and rearwardly facing surfaces and lower forwardly and rearwardly facing surfaces.
U.S. Pat. No. 3,934,537, which issued to Hall on Jan. 27, 1976, describes a vibration isolating mount for an outboard motor. The arrangement includes an upper mount and a pair of lower mounts secured to the propulsion unit in vertically spaced relation and rearwardly of or behind the drive shaft. The top mount includes a crossbar which has a wedged-shaped cross section with the upper and lower surfaces thereof converging in the direction of propeller thrust, which is supported by a resilient bushing within a casing, and which has outer ends extending from the casing transversely to the direction of propeller thrust for connection to a swivel bracket.
U.S. Pat. No. 3,982,496, which issued to Blanchard on Sep. 28, 1976, describes a seal and isolation mounting system. A resilient member comprises an annular sealing portion including an endless surface defining a central opening and a plurality of annularly spaced extensions which project outwardly from the annular sealing portion and constitute elastomeric mounts.
U.S. Pat. No. 4,583,953, which issued to Nakase on Apr. 22, 1986, describes an outboard motor. Embodiments of vibration damping devices for preventing the transmission of vibrations from the power head of an outboard motor to the transom of a boat are described. A vibration damping pad is interposed between the power head and the driveshaft housing to isolate vibrations.
U.S. Pat. No. 4,726,795, which issued to Uehara on Feb. 23, 1988, describes a non-vibrating structure of an outboard motor. A vibration damping structure for an outboard drive has a driveshaft housing with a pair of spaced apart side walls. A resilient coupling is provided between the spaced side walls for damping vibrations.
U.S. Pat. No. 4,723,926, which issued to Uehara on Feb. 9, 1988, describes a non-vibrating structure of an outboard motor. The arrangement has a driveshaft housing having spaced apart walls defining a hollow interior. An exhaust pipe extends into the hollow interior and resilient elements are interposed between the exterior walls of the exhaust pipe and the interior walls of the driveshaft housing for providing a resilient connection therebetween for damping vibrations.
U.S. Pat. No. 4,726,799, which issued to Harada et al. on Feb. 23, 1988, describes an outboard motor arrangement. It has an improved power head construction embodying a hinged cover member that is pivotal to offer access to the engine for servicing without necessitating its removal. In addition, an elastomeric support is provided for the engine that minimizes the transmission of vibrations from the engine to the associated watercraft.
U.S. Pat. No. 4,979,918, which issued to Breckenfeld et al. on Dec. 25, 1990, describes an outboard motor vibration isolation system. It comprises a propulsion unit with a cavity defined in part by a wall, an opening communicating with the cavity, a rubber mount insertable into the cavity through the opening, and an expandable wedge insertable through the opening and into the cavity.
U.S. Pat. No. 5,192,235, which issued to Dunham et al. on Mar. 9, 1993, describes an outboard motor vibration isolation system including an improved rubber mount. The mount is located in a cavity and includes an annular outer shell having an outer surface engaging the wall and an inner surface defining an axially extending bore having a minimum diameter, an inner core extending through the bore, adapted to be connected to a kingpin, and including an end core portion having a diameter less than the minimum diameter.
U.S. Pat. No. 5,219,306, which issued to Takahashi on Jun. 15, 1993, describes a vibration absorbing structure of an outboard motor. It comprises an elastic abutment between the driveshaft housing and clamping bracket which has a greater resilience than the connection between the driveshaft housing and the steering shaft of the outboard motor. This permits the absorption of rotational couples caused by vibrations without introducing undue resilience in the steering system of the outboard drive.
U.S. Pat. No. 6,146,220, which issued to Alby et al. on Nov. 14, 2000, discloses a pedestal mount for an outboard motor. The motor is mounted to a transom of a boat with a pedestal that is attached either directly to the transom or to an intermediate plate that is, in turn, attached to the transom. A motor support platform is attached to the outboard motor, and a steering mechanism is attached to both pedestal and the motor support platform. The tilting mechanism is attached to the motor support platform and to the outboard motor. The outboard motor is rotatable about a tilting axis relative to both the pedestal and the motor support platform.
U.S. Pat. No. 6,149,475, which issued to Tasaka et al. on Nov. 21, 2000, describes a tiller mounting arrangement. A tiller arm is movable relative is to the outboard motor about a transverse axis and is arranged to steer the motor about the vertical axis. A resilient member is juxtaposed between a mounting bracket and a mounting structure. A gap is defined between a face of the resilient member and the tiller arm such that the resilient member may freely vibrate within the gap without that face of resilient member contacting the tiller and directly translating vibrational energy to the tiller arm.
U.S. Pat. No. 6,419,534, which issued to Helsel et al. on Jul. 16, 2002, discloses a structural support system for an outboard motor. It uses four connectors attached to a support structure and to an engine system for isolating vibration from being transmitted to the marine vessel to which the outboard is attached. Each connector comprises an elastomeric portion for the purpose of isolating the vibration. Furthermore, the four connectors are disposed in a common plane which is generally perpendicular to a central axis of a driveshaft of the outboard motor.
U.S. Pat. No. 6,830,492, which issued to Magee et al. on Dec. 14, 2004, discloses a marine drive trim cylinder with a two stage damping system. The system is provided for a trim cylinder mount of a marine drive unit. The mounting bushings comprise inner and outer tubes with an elastomeric material disposed between the inner and outer tubes. The elastomeric material is structured to provide a soft rate of stiffness in response to relatively light loads, such as shifting loads, and a harder rate of stiffness in response to higher loads, such as during high thrust loads or wide open throttle operation of a marine vessel.
U.S. Pat. No. 7,204,732, which issued to Mizuguchi on Apr. 17, 2007, describes an outboard motor. It is adapted to be mounted on a stern of a boat and includes an internal combustion engine installed on a frame and a propeller powered by the engine to propel the boat, elastic members are interposed between the engine and the frame, thereby enabling vibration and noise produced by engine operation to be reduced without degrading steering performance.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
It is important that mounts for a marine propulsion device perform the function of isolating vibration and noise from being transmitted from the outboard motor to a marine vessel through the support structure of the marine propulsion device. Typically, elastomeric-type mounts are used to accomplish this isolation. However, it would be significantly beneficial if the elastomeric mounts could be located at a region that allowed easy access to the mounts and easy replacement of the mounts.
A support system of a marine propulsion device made in accordance with a preferred embodiment of the present invention comprises a mounting bracket, a plurality of mounts attached to both the mounting bracket and to a transom of a marine vessel, and a support structure of an outboard motor which is attached to the mounting brackets. In a particularly preferred embodiment of the present invention, it further comprises a transom bracket attached to the transom of a marine vessel. The plurality of mounts are attached to the transom bracket and to the mounting bracket. The mounting bracket has a central plane which is generally vertical and extends perpendicularly through the transom and parallel to a keel of a marine vessel. This central plane is typically a plane of symmetry of the mounting bracket. At least a first one of the plurality of mounts is disposed entirely on a port side of the central plane and at least a second one of the plurality of mounts is disposed entirely on a starboard side of the central plane. In a particularly preferred embodiment of the present invention, the plurality of mounts is symmetrically disposed about the central plane.
In one embodiment of the present invention, a trim cylinder is attached to the mounting bracket and to the outboard motor. A support structure of the outboard motor can be detachable from the outboard motor. Each of the plurality of mounts in a preferred embodiment of the present invention comprises an elastomeric element which is disposed functionally between first and second rigid members. In a typical embodiment of the present invention, the first and second rigid members are metallic and coaxial with each other. The elastomeric element is disposed coaxially between the first and second rigid members in a preferred embodiment of the present invention. The first rigid member is attached to the transom and the second rigid member is attached to the mounting bracket in a preferred embodiment. The plurality of mounts is generally stationary with respect to the transom when the outboard motor moves relative to the transom. The outboard motor is movable relative to the plurality of mounts when the outboard motor moves relative to the transom. In a particularly preferred embodiment of the present invention, the plurality of mounts comprises four mounts and a first pair of the plurality of mounts is disposed entirely on the port side of the central plane and a second pair of the plurality of mounts is disposed entirely on the starboard side of the central plane.
The present invention will be more fully and completely understood from a reading of the description of the preferred embodiment in conjunction with the drawings, in which:
Throughout the description of the preferred embodiment of the present invention, like components will be identified by like reference numerals.
With continued reference to
As described above, the trim cylinder 40 illustrated in
The present invention provides several significant advantages. For example, with the mounts, 21-24, located between the transom plate 50 and the mounting bracket 10, significant additional mass is located on the outboard motor side of the mounts. For example, the mounting bracket 10 and the trim cylinder 40 represent significant weight that would otherwise be directly connected to the transom of the boat. In the configuration shown in the figures, the present invention supports that weight away from the transom and isolated from the boat. This additional mass on the outboard motor side of the mounts significantly dampens the vibration caused by the operation of the engine. In addition, the shift shaft (not shown in the figures) of the outboard motor and the tube in which the shift shaft is located are both on the same side of the mounts, 21-24. In configurations known to those skilled in the art, it is not uncommon for the shift shaft tube to be directly coupled to the transom bracket while the shift shaft itself is coupled to the outboard motor. This creates a potential relative movement between the shift shaft and the tube in which it is located. This problem is avoided because of the placement of both the shift shaft and its tube with the outboard motor on an opposite side of the mounts relative to the transom bracket and the marine vessel. Another advantage of the present invention is that it moves the mounts, 21-24, closer to the transom than in outboard motor support systems known to those skilled in the art. This moves the mounts in a forward direction relative to the typical flow of water passing under a marine vessel and then upward toward the lower portion of the outboard motor. If the mounts were located on the outboard motor itself, they could provide additional drag as they passed through water flowing rapidly relative to the lower portion of the outboard motor.
With continued reference to
With continued reference to
With continued reference to
In
Although the present invention has been described with particular specificity and illustrated to show a preferred embodiment, it should be understood that alternative embodiments are also within its scope.
