Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
DAMPING DEVICE FOR AN OUTBOARD MOTOR
Document Type and Number:
WIPO Patent Application WO/2000/064734
Kind Code:
A1
Abstract:
The invention relates to a damping device for an outboard motor which comprises one or more elastic damping elements (1, 2, 10, 11; 21, 22) mounted and secured between an outboard motor and the rear of a boat. A damping device for an outboard motor formed according to the invention comprises a damping element which extends through both sides of the back board of the boat and the damping device comprises one or more clamping mechanisms (3-8, 12-20) which extend through both sides of the back board, have a damping effect, and regulate the pressing force.

Inventors:
Karvinen, Matti (Suunnistajantie 7 F 45 Kuopio, FIN-70200, FI)
Application Number:
PCT/FI2000/000341
Publication Date:
November 02, 2000
Filing Date:
April 20, 2000
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
Karvinen, Matti (Suunnistajantie 7 F 45 Kuopio, FIN-70200, FI)
International Classes:
B63H20/02; B63H21/30; F02B61/04; (IPC1-7): B63H20/02
Foreign References:
US2209592A1940-07-30
US2738751A1956-03-20
US3884174A1975-05-20
Attorney, Agent or Firm:
Pitkänen, Hannu (Patent Agency Pitkänen Oy P.O. Box 1750 Kuopio, FIN-70211, FI)
Download PDF:
Claims:
CLAIMS
1. A damping device for an outboard motor which comprises one or more elastic damping elements (1,2,10,11; 21,22), which are mounted and secured between the outboard motor and the rear of the boat, c h a r a c t e r i z e d in that the damping elements extend through both sides of the boat's back board, and in that the damping device comprises one or more clamping mechanisms (38,1220) which extend through both sides of the boat's back board, have a damping effect, and regulate the pressing force.
2. A damping device for an outboard motor formed in accordance with Claim 1, c h a r a c t e r i z e d in that the damping element comprises an elastic damping element (1,2,10,11) and a hard casing (1,10) which distributes the pressing force evenly on the elastic damping element and is mounted in between the clamps of the outboard motor.
3. A damping device for an outboard motor formed in accordance with Claim 1 or 2, c h a r a c t e r i z e d in that the damping element (21,22) is made from two or more different parts which are mounted between the clamp mechanisms (38, 1220) of the outboard motor and the rear of the boat.
4. A damping device for an outboard motor formed in accordance with any of the Claims 13, c h a r a c t e r i z e d in that a bracing piece is mounted between the elastic damping element (1,2,10,11) and the rear of the boat and/or inside the damping element.
5. A damping device for an outboard motor formed in accordance with any of the Claims 14, c h a r a c t e r i z e d in that the clamping mechanism (38,1220) comprises a collar which extends through the back board of the boat and regulates the pressing force.
6. A damping device for an outboard motor formed in accordance with the Claim 5, c h a r a c t e r i z e d in that the collar of the clamping mechanism (38,1220) comprises an elastic damping collar (3,12), an inner collar (4) which is pushed through the hole in the center of the damping collar, washers (13,15) in between the inner collar, the damping collar and the damping element, flanges (5,16) on both ends of the inner collar, a screw mechanism (6,14) extending through the inner collar and the damping element, a base plate (7,19) on the end of the screw mechanism outside of the damping element, and one or more adjustment nuts (8, 17) for adjusting the damping margin of the clamping mechanisms.
Description:
DAMPING DEVICE FOR AN OUTBOARD MOTOR The invention relates to a device for damping the vibration and noise from an outboard motor, which is comprised of an elastic damping element mounted between the outboard motor and the rear of the boat.

In a commonly known method of mounting and securing an outboard motor to a boat, the motor is mounted directly to the back board of the boat with a clamp-like fastening mechanism which is part of the motor. These also generally comprise a jaw-like part (cast, for example, out of metal), with one or more manually tightened clamping screws. The friction produced between the jaws and the boat back board, which results from the pressing force produced from the clamping screws, enables the jaw-like clamp part, which is connected to the outboard motor, to remain secured to the boat in the desired way. The tightening mechanism enables the outboard motor to be easily and quickly mounted and dismounted.

Another known way of mounting an outboard motor (often in addition to the previously mentioned clamping) is with a screw fastener through the back board, whereby, in addition to being held in place by friction, the motor is also held in place mechanically through the holes made in the back board. Thus, the motor will not come loose even if the motor's clamping screws become loosened.

In general, an outboard motor can be mounted well to a boat using the aforementioned methods, however, the noise and vibration caused by a motor mounted to a boat in these ways is transferred directly to the frame and other parts of the boat. The sounding board formed by the boat and the different resonant frequencies produced in boat structures at certain revolution frequencies of the motor strengthen the noise and vibration. Loud noise and strong vibrations are tiring and disadvantageous to the boater and his/her health. When boating close to shore, the noise also becomes disadvantageous to others and to nature.

Up to the present, damping padding, for example, a rubber splash guard, has been placed between the clamp part on the outboard motor, which has been tightened with screws, and the back board of the boat in order to reduce the vibration and noise of the outboard motor. This method has had a slight damping effect, which disappears once the motor is secured to the back board.

The object of the invention is to provide a device, which reduces the disadvantageous noise and vibration caused by an outboard motor, and whereby the motor can reliably and easily be secured to the boat. The object of the invention is

also to provide a device, which is advantageous to produce and can be adapted for use with all new and old outboard motors and boats, which are in use.

The object of the invention is accomplished with a device for damping the noise and vibration of an outboard motor, the characteristics of which are set forth in the claims.

The damping element in a damping device for an outboard motor formed in accordance with the invention extends through both sides of the boat's back board, and the damping device comprises one or more clamping mechanisms, which extend through both sides of the boat's back board, have a clamping effect and regulate the pressing force. Since the damping element extends through the boat's back board, the damping action is effective. A clamping mechanism formed in accordance with the invention reduces the transference of the natural vibration of a piston engine type outboard motor to the boat frame and structures. Since it extends through the back board, an effective connection is produced, and the clamping mechanism also ensures the functioning of the damping element without jeopardizing the connection of the outboard motor and damping device to the boat's back board.

In an advantageous application of the invention, casing is placed between the damping element and outboard motor clamps, to distribute the pressing force evenly to the hard damping element. Due to the casing, the force is evenly distributed, whereby the flexible play produced by the damping element is preserved, although the motor's clamping screws are pressing the motor against the damping element.

In second advantageous application of the invention, the damping element is produced from two or more different parts, which are mounted between the outboard motor's clamping mechanism and the rear of the boat. The simple and small size of the parts make costs for manufacturing and for the material for the damping device minimal.

In a third advantageous application of the invention, a bracing piece is mounted between the damping element and the rear of the boat, and/or inside the elastic damping element. By adding bracing pieces, the damping device is secured more firmly, which better ensures that big and powerful outboard motors will remain firmly in place.

In a fourth advantageous application of the invention, the clamping mechanism comprises a collar unit which regulates the clamping. The collar unit which

regulates the clamping is required for the elastic clamping mechanism to function.

The collar unit makes it possible to restrict the pressing force which is exerted from the clamping mechanism onto the damping element, whereby the flexible play of the damping element is preserved, nor is any vibration produced from contact between the hard parts on the outboard motor and the boat.

In a fifth advantageous application of the invention, the collar unit of the clamping mechanism comprises an elastic damping collar, an inner collar which has been pushed through the hole in the center of the damping collar, washers located between the inner collar, damping collar and damping element, flanges at both ends of the inner collar, a screwing mechanism which extends through the inner collar and damping element, a base plate on the outside of the damping element on the end of the screwing mechanism, and one or more adjustment nuts to adjust the damping margin of the clamping mechanism. The previously described collar unit can be assembled mainly using standard parts, such as screws, nuts and base plates. Thus, manufacturing and repairs are easy and advantageous.

The invention will now be described with reference to the accompanying drawings, in which Figure 1 illustrates a certain damping device formed in accordance with the invention, as viewed from the side, Figure 2 illustrates a damping device formed in accordance with Figure 1, as viewed from the front, Figure 3 illustrates a certain second application of a damping device formed in accordance with the invention, as viewed from the side, and Figure 4 illustrates a damping device formed in accordance with Figure 3, as viewed from the front.

A damping element in an application of a damping device formed in accordance with Figures 1 and 2 is comprised of two different parts, one of which is a bigger main part 1,2 which reaches over the upper edge of the back board and through both sides, and the second of which is the supplement piece 10,11 which is located on the inner side of the back board. Both parts of the damping element are composed of a casing part 1 and 10 on the outer surface of the damping element, which establishes the distribution of the clamping pressure, and of an elastic damping part 2 and 11. The casing part and damping part stay connected to one another by the clamping mechanism, but they can also be held together by other means, for example, with glue. The main part of a damping element formed in accordance with the application in Figures 1 and 2 can be secured to the back board

of the boat with three clamping mechanisms 3-8 and 12-20, which regulate the clamping and are placed vertically at two different elevations, such that one upper clamping mechanism 3-8 is higher than two lower clamping mechanisms 12-20. As is shown in Figure 2, the upper clamping mechanism is placed on a parallel plane to and half-way in between the lower clamping mechanisms. The end of it extends through the main part of the damping element to the inner side of the back board.

The lower supplement part of the damping element on the inner side of the back board acts as a damping counterpart for the lower clamping mechanisms. As seen in Figure 1, the part of the damping element on the outer side of the back board additionally has a plicature 9 formed in it, which prevents the outboard motor from sliding and falling into the water, in the event that the clamping mechanisms should remain open, or otherwise open for some reason.

The application in Figures 1 and 2 of the upper clamping mechanism belonging to the damping device consists of a damping collar 3 made of elastic material, an inner collar 4 located in the center hole of the damping collar, flanges 5 located at the ends of the inner collar, a clamp cap screw 6 which extends through the inner collar, through the parts of the damping element on the outer and inner side of the back board, and through the back board of the boat to the inner side of the back board, a body base plate 7 on top of part of the damping element which is on the inner side of the boat back board, and a ring nut 8 tightened on the end of the clamp cap screw 6 on top of the body base plate. There are no clamping mechanisms between the different parts of the clamping mechanism formed from parts 3-8, other than the clamp cap screw and ring nut. The aggregation force caused by these holds the different parts of the clamping mechanism together in the desired way. The inner collar and clamp cap screw can be sealed with some sealing agent, if desired, such as polyurethane.

Lower clamping mechanisms formed according to Figures 1 and 2 consist of a damping collar 12, a thicker plug tap 14 which is pushed through the center part of the damping collar, a sealing face 13 between the damping collar and plug tap, rubber waterstops 15 located on both ends of the damping collar, and base plates 16 located on top of the waterstops and which produce the sealing effect and pressure of the damping element. Additionally, the clamping mechanism comprises nuts 17 which fit the plug tap 14 and are tightened against the base plates, waterstops and damping collar, outer base plates 18 on top of the nuts, an outer body base plate 19 for the supplementary part of the damping element, located on the inner side of the back board, and outer nuts 20 on the ends of the plug tap, whereby the outboard

motor's clamp can be secured to the damping device. The vibration-damping clamping mechanism formed from parts 12-20 is primarily held together using nuts 17. By adjusting the tightness of the nuts, the rigidity of the connection can be altered, whereby the damping effect of the clamping mechanism and the natural frequency of the system can be regulated. The sealing face 13 can be formed out of elastic sealing compound, but it can also be, for example, a rubber sealing collar.

The center part of the damping collar 12 is connected to the thicker plug tap 14, which determines the distance between the waterstops 15 and base plates 16, whereby the pressing force concentrated on the damping element is kept even.

When the nuts 17 are screwed onto the plug tap against the thicker part of the plug tap, the length of which is less than that of the damping collar, the base plates 16 press against the waterstops 15, whereby the damping collar is pressed together.

When the damping collar is pressed together, it swells in a direction perpendicular to that of the pressing action and fills the potential gap between the plug tap and the damping collar. Thus, the hole for the plug tap is sealed. A sealant can be added between the plug tap and damping collar to ensure the ultimate water-tightness of the structure.

The clamping mechanisms of the damping device ensure that the motor and damping element will stay in place behind the boat, without interfering with the functioning of the damping element. The damping element damps the vibratory impulses from the motor and additionally reduces the natural frequencies of the boat's and outboard motor's vibrational system, whereby by appropriately regulating the play of the damping element and thus the resilience of the motor connection, the vibration and the noise from the boat can be reduced. The correct damping capacity of damping collars adapted for outboard motors with varying powers can be defined with tests and calculations. With the results of the definitions, the correct size of damping collar and/or correct elasticity for the damping collar material for a certain damping device can be obtained.

Figures 1 and 2 present a more advantageous application of a damping device suitable for less powerful outboard motors, under 10 hp, when the lower clamping mechanisms and the damping element 10,11 on the inner side of the back board are not included. Thus, the outboard motor is primarily secured to the damping elements by the strength of its own clamps, but the clamping mechanism 3-8 may be constructed such that it also helps the outboard motor to stay secured.

The damping element in the application illustrated in Figures 3 and 4 comprises two pairs of damping elements 21,22, mounted separately and parallel to one another, whereby the damping element comprises four parts all together. The parts of the damping elements are produced from soft, but also somewhat rigid material, such as, for example, polyurethane. The damping element parts in this application do not include a separate casing or bracing pieces. The damping element parts are intended to be mounted on the clamp jaws and clamping screws on the outboard motor.

Damping clamping mechanisms are comprised of four pieces all together. Two for each damping element pair. The clamping mechanisms are mounted on the damping element pairs, according to Figure 4, side by side at two different elevations on the boat's back board; the first two above the splash line, and the second two below the splash line. The clamping elements above the splash line are formed in accordance with the upper clamping element 3-8 in the application in Figures 1 and 2, and the ones below the splash line are formed in accordance with the lower clamping elements 12-20 in Figures 1 and 2. A damping element in an application of the damping device which is in accordance with Figures 3 and 4 is simpler and smaller with respect to an application implemented according to Figures 1 and 2, thus its costs for production and material are less than those for the damping element in the application presented in Figures 1 and 2. The application of a damping device formed in accordance with Figures 3 and 4 can also be applied to powerful and heavy outboard motors regardless of the damping element's structure.

Damping elements can be built with different constructions to suit outboard motors of different sizes and strengths using different damping element structures and varying numbers of clamping mechanisms. With the different constructions of damping elements and varying numbers of clamping mechanisms, a suitable and economically optimal product can be obtained for every size of outboard motor.

This invention is not limited to the advantageous applications presented herein; it is versatile and its form may vary within the frames of the concept of the invention set forth in the claims.