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Publication numberUS3136280 A
Publication typeGrant
Publication dateJun 9, 1964
Filing dateMar 5, 1962
Priority dateMar 5, 1962
Publication numberUS 3136280 A, US 3136280A, US-A-3136280, US3136280 A, US3136280A
InventorsBergum Robert L
Original AssigneeBergum Robert L
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Outboard motor attachment
US 3136280 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

June 9, 1964 R. L. BERGUM 3,136,280

OUTBOARD MOTOR ATTACHMENT Filed March 5, 1962 United States Patent 3,136,280 GUTBOARD MOTOR ATTACHMENT Robert L. Bergum, 333 W. Superior St., Duluth, Minn. Filed Mar. 5, 1962, Ser. N0. 177,614 1 Claim. (Cl. 11517) This invention relates in general to an outboard motor and has more particular reference to an attachment for an outboard motor which is connectible to the cavitation plate of an outboard motor which is automatic in its action, and acts to reduce the efliciency of the outboard motors propeller and retard the speed of the boat on which the outboard motor is mounted to an extent suflicient to permit trolling.

It is well appreciated among fishermen that when one is trolling, it is desirable to travel at a very low speed. Although an outboard motor may be operated at dilferent speeds to propel a boat correspondingly, it is often desirable to operate the boat at a lower rate of speed than is possible to throttle down an outboard motor; particularly an outboard motor of a larger horsepower rating. It is the principal object of the present invention to provide a simple and inexpensive device which is attached to the outboard motor for operating it and a boat to which it is attached'at a very low rate of speed, yet, permitting its operator to resume full power and speed simply increasing the throttle setting of the outboard motor.

I am aware that a trolling plate attachment for outboard motors, used for the purpose of reducing the speed of boat movement to an extent suflicient to allow trolling, is not new per se. I am further aware that the present invention is not the first invention to employ as an object an attachment of the character referred to which will act automatically, by moving into an operative speed reducing position when the motor is throttled down below a predetermined throttle setting, and to move into an inoperative position when the motor is being operated at or above said settings. However it is a more particular object of the present invention, to provide an attachment which consists in part of a device that automatically moves the trolling plate into operative position when the motor is throttled down below a predetermined throttle setting, locking the trolling plate into that operative position until the throttle setting of the motor is increased sufiiciently to release the automatic locking device by exhaust and propeller wash pressure channelled through the trolling plate and against a point on the automatic locking device; the propeller wash then automatically moving the trolling plate to an inoperative position.

Another object is to provide a trolling plate attachment of a type which can be manufactured at a reasonable cost, is of simple and durable construction, and can remain attached to the outboard motor as an integrated part thereof Without interference with the normal operations of the same.

Other objects will appear from the following description, the claim contained herein, and from the annexed drawing, in which like reference characters designate like parts throughout the several views, and wherein:

FIGURE 1 is a side elevation view of the present invention, a motor on which the attachment is mounted being illustrated fragmen-tarily, the full lines showing an operative position of the plate members of the device, the broken lines showing an inoperative position of the plate member;

FIGURE 2 is a rear elevation view of the attachment taken from the left of FIGURE 1;

FIGURE 3 is a transverse sectional View through the motor taken substantially on line 3-3 of FIGURE 1, the attachment constituting the present invention being shown in top plan; and

3,136,280 Patented June 9, 1964 ice FIGURE 4 is a perspective view of the present invention not attached to an outboard motor.

The reference numeral 10 has been applied generally in the drawings, to designate a conventional outboard motor, said motor having the usual cavitation plate 12 and the propeller 14.

The present invention consists of the mounting frame 16; the speed reducing plate 18, and an adjustable automatic locking device 20.

The mounting frame 16 attaches to the cavitation plate 12 of the motor 10 by means of four bolts at 22.

The speed reducing plate 18 is attached to two arms 24 by means of rivets 26; and arms 24 are secured to the mounting frame 16 by a removable pin 28 which forms a horizontal axis at the point of attachment 28 which allows the speed reducing plate to swing freely from the operating position as indicated by the solid lines in FIG- URE 1 to the inoperative position as indicated by the broken lines in FIGURE 1, and vice versa.

The speed reducing plate 18 is provided with a slot at 42 to permit the escape of the motors exhaust and to provide a channel for the passage of propeller wash to cause the release of the adjustable automatic locking device 20.

The adjustable automatic locking device consists of an upper member 44 and a lower member 46 which are joined together at-30 by an adjustable-tension spring hinge 40; said spring hinge is obtained from a'manufacturer, is produced for a variety of industrial and domestic uses and its construction is not claimed as a part ofthe present invention. The upper member 44 and the lower member 46 are mitered so that their greatest angle to each other, as indicated by the solid lines of FIGURE 1 is less than degrees. The adjustable tension spring hinge is arranged so that its tension is applied to maintain the greatest angle between the upper member 44 and the lower member 46; so that the tension on the spring hinge is greatest when the device is in an inoperative position as indicated by FIGURE 1; however, due to the leverage arrangement, the plate in this inoperative position has little downward pressure.

The upper member 44 is attached to the mounting frame 16, by a removable pin 32 which forms a horizontal axis at the point of attachment which allows the upper member 44 to move freely from the operative position as indicated by the solid lines in FIGURE 1 to the inoperative position as indicated by the broken lines in FIGURE 1; the point of attachment 32 being above the horizontal center line of the point of attachment 28.

The lower member 46 is attached to the speed reducing plate 18 by means of a bracket 34 which is riveted to said plate 18 at 36; said lower member 46 being attached to said bracket 34 by means of a removable pin 38.

The pin 28 and the pin 32 are removable in order to allow the speed reducing plate 18 and the adjustable automatic locking device 20 to be quickly and easily removed from the mounting frame 16, leaving only the mounting frame 16 attached to the outboard motor during such occasions when the operator desires maximum speed and efiiciency, such as racing, water skiing, and running about, and permits quick re-attachment of the device during such occasions when the operator washes to utilize it.

The pin 38 is removable in order to allow said lower member 46 to be disengaged from the speed reducing plate 18 to permit easy access to the adjustable tension spring hinge 40 for the purpose of adjustment.

The removable pin 38 forms a horizontal point of axis which is to the rear of the vertical center line of the point of axis 28 and which is above a line passing through the centers of the point of axis 32 and the point of axis of the spring hinge 40. The purpose of this linkage is to create certain advantages of leverage for a purpose to be made presently apparent.

In trolling, the outboard motor would be throttled down to a low setting. When the motor is operated at' said low isetting, the propellers force would not be sufiicient to overcome the tension on the spring hinge 40; as a result, the adjustable locking device 20 will assume its operating position as indicated by the solid lines in FIGURE 1', bringing the speed reducing plate 13 into the path of the propeller wash to have the eifect of slowing the speed of movement of the boat on which the motor is mounted, to an extent sufiicient to permit trolling. At the operating position, the automatic locking device 20 becomes set or locked. The greatest advantage of the. points of leverage being achieved, holding the speed reducing plate 18 in a rigid position.

If, however, the speed of the motor is increased above a predetermined throttle setting, the propellers force and increased exhaust pressure will be channelled through the slot 42 in the speed reducing plate 18 and against the face of the upper member 44 with sufiicient pressure to release the locking effect above described; when this release is achieved, the propellers force can easily overcome the tension of the spring hinge and move the mechanism into an inoperative position as indicated by the broken lines of FIGURE 1.

The throttle setting at which the speed reducing plate 18 will be automatically made operative or inoperative by the automatic locking device 2% can be governed by adjusting the tension of the spring hinge to suit the size and power of the individual motor and desires of its operator.

The foregoing is considered as illustrative only of the principles of the invention. It is believed apparent that the invention is not necessarily confined to the specific use or uses thereof described above, since it may be utilized for any purpose to which it may be suited. Nor is the invention to be necessarily limited to the specific construction illustrated and described, since such construction is only intended to be illustrative of the principles of operation and the means presently devised to carry out said principles, it being considered that the invention comprehends any minor change in construction that may be permitted within the scope of my claim.

My claim is as follows:

A mechanism comprising a mounting frame, a speed reducing plate pivoted to said frame on a first horizontal axis, an arrangement of two members hinged together by the use of a spring hinge; one member being attached at one end to said mounting frame on a second horizontal axis located to the rear of and parallel to said first horizontal axis; the other member being attached at its opposite end to said speed reducing plate by means of a horizontal pin parallel to the second horizontal pin; said members being joined togetherin such a manner so as to provide that the spring hinge will motivate said members to assume a position toward each other which is slightly less than degrees to each other, the purpose ofv said mechanism being to form a brace or support for said speed reducing plate; said support being made rigid by the nearly dead center position of the members; said members plate to a vertical position and restore the near dead center support and brace effect at such time as the throttle setting of the outboard motor is reduced and the wash of the propeller diminished.

References {Zited in the file of this patent UNITED STATES PATENTS Karasinski Aug. 11, 1936 Langdon Feb. 4, 1941 Ehmke Sept. 23, 1941

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2050336 *Dec 23, 1935Aug 11, 1936Johnson Motor CompanyOutboard motor
US2230958 *Oct 12, 1939Feb 4, 1941Langdon Elmer ETrolling plate attachment for outboard motors
US2256898 *Apr 10, 1939Sep 23, 1941Ehmke Gustav A WTrolling plate
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3209716 *Dec 1, 1964Oct 5, 1965Hartley Roy ESpeed reduction device for a screw-driven power boat
US4048940 *Mar 18, 1977Sep 20, 1977Smith William LTrolling attachment for outboard engine
US4549498 *Aug 23, 1982Oct 29, 1985I.M.S., Inc.Speed controlling apparatus
US4993978 *Mar 12, 1990Feb 19, 1991Johannes John TBoat motor reflector
US5070803 *Nov 1, 1990Dec 10, 1991Smith Gene AMethod and apparatus for reducing the trolling speed of boats having inboard engines
US6073570 *Oct 1, 1998Jun 13, 2000Stirtz; Ronald H.Trolling plate assembly
US6161492 *Mar 17, 1999Dec 19, 2000Dyer; William B.Trolling plate construction
US6397772 *Apr 6, 2000Jun 4, 2002Dale ChristensenBoat motor trolling attachment
US6425787Sep 22, 2000Jul 30, 2002Brian R. HersomOutboard reflector kit
US9776701Feb 22, 2013Oct 3, 2017Howard Charles PietschBoat speed minimisation system
U.S. Classification415/8, 114/145.00A
International ClassificationB63H25/00, B63H25/50
Cooperative ClassificationB63H25/50
European ClassificationB63H25/50