US 3763819 A
An electric motor drives a flexible drive shaft in a curved rigid transmission tube fixed to the motor. The motor and tube are pivoted to a bracket that can be clamped to the propellor housing of an outboard motor so that the end of the flexible shaft can be swung to or from the propellor of the outboard motor. The flexible shaft drives a driving member releasably engageable with the propellor for rotating the same at low speed, for trolling.
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Description (OCR text may contain errors)
United States atent Mays 3,763,819 Oct. 9, 1973 TROLLING ATTACHMENT FOR OUTBOARD MOTORS  Inventor: Kenneth R. Mays, Rt. 2, St. James,
Minn. 56081  Filed: Apr. 25, 1972  Appl. No.: 247,355
 US. Cl. 115/117, 115/18 E  Int. Cl B6311 21/26  Field of Search 115/17, 18 R, 18 A, 115/18 E, 34; 248/4  References Cited UNITED STATES PATENTS 2,504,833 4/1950 Hann 115/17 3,315,631 4/1967 Bass .1 115/18 A 3,139,853 7/1964 McCarthy 115/17 Primary Examiner-George E. A. Halvosa Assistant Examiner-Sherman D. Basinger Attorney-Leo A. Rosetta et a1.
[5 7] ABSTRACT An electric motor drives a flexible drive shaft in a curved rigid transmission tube fixed to the motor. The motor and tube are pivoted to a bracket that can be clamped to the propellor housing of an outboard motor so that the end of the flexible shaft can be swung to or from the propellor of the outboard motor. The flexible shaft drives a driving member releasably engageable with the propellor for rotating the same at low speed, for trolling.
5 Claims, 3 Drawing Figures TROLLING ATTACHMENT FOR OUTBOARD MOTORS BACKGROUND OF THE INVENTION This invention relates to attachments for outboard motors to permit trolling at low speed.
Outboard motors are used by fishermen, particularly to travel to and from fishing grounds, but when it is desired to troll for the fish the conventional outboard motor is unsatisfactory. It is difficult to operate such motors at a low enough speed to troll successfully and the noise created by such motors often frightens the fish and detracts from the success of the fishing activities.
It has been proposed to attach an electric motor to an outboard motor and to operate the electric motor to drive its own small propellor in lieu of operating the outboard motor, for the purpose of trolling at low speed. But, in such proposals, the electric motor with its attached propellor are at all times below the water line and thus add undesirable drag when the boat is propelled by the outboard motor. Furthermore, such electric motors are subject to deterioration by constant exposure to the surrounding water and are exposed to collision dangers.
It has also been proposed to modify outboard motors so that the drive to the propellor may be switched from the regular internal combustion'engine to an electric motor, permanently built into the device. Such proposals, however, involve considerable modification of the outboard motor and additional parts and expenses.
SUMMARY OF THE INVENTION The present invention proposes to provide an electric motor to be used for trolling and wherein readily manipuable means .permit external connection from the electric motor to the conventional outboard motor propellor, whereby the propellor may be driven directly by the electric motor, withiout in any way modifying the outboard motor structure.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of a more or less conventional outboard motor with the attachment of the present invention thereon;
FIG; 2 is an enlarged horizontal sectional view taken substantially along the line 2-2 of FIG. 1; and
FIG. 3 is a fragmentary enlarged sectional view taken generally along the line 3-3 of FIG. 1.
DESCRIPTION OF A PREFERRED EMBODIMENT In the drawings, numeral 2 indicates generally a more or less conventional outboard motor having a motor housing 4, a clamp structure 6, by which the outboard motor may be secured to the transom of a boat and a downwardly extended housing 8 in which a drive shaft 10 extends. A rearwardly facing propellor 12 is journalled at a lower end of the housing 8 and is driven by the shaft 10, usually through bevelled gears (not shown).
The structure referred to above is merely illustrative of a more or less conventional outboard motor adapted to receive applicant's invention. The attachment of the invention comprises a clamp structure 14 having side straps l6 and a spacer block 18. The spacer block is preferably provided with a shallow notch 20 to engage the forward edge of the housing 8 and the straps 16 extend rearwardly therefrom on opposite sides of the housing and are brought together by a clamp bolt and nut 22 and 23 to securely hold the attachment bracket in place on the housing 8 at a position above the water line.
' The straps I6 extend forwardly from spacer l8 and an electric motor 24 is pivotally mounted on the bracket between the bracket straps 16, on suitable pivot pins 26. Attached to the electric motor 24 and extending coaxially with the motor drive shaft (not shown) is a substantially rigid tube 28 which, as shown in solid lines in FIG. 1, extends downwardly from the electric motor 24 and is then curved to extend toward the center or axis of the propellor 12. Connected to the drive shaft of the motor is a flexible shaft indicated by dotted line 30 extending along the inside of the tube 28 and terminating in a rotatable driving member 32 journalled at the rearward end of tube 28.
Driving member 32 may be in the form of a flat disc having a plurality of rearwardly extending pins 34 fixed thereon. When the apparatus is in the position shown in full lines in FIG. 1, the pins 34 embrace the hub portion of propellor 34 and actually engage the sides of the vanes thereof so that rotation of the driving member 32 causes rotation of the propellor 12 in an obvious manner. Thus, the electric motor, which is above the water line, may be energized through power conductors 36 to directly rotate the propellor 12 at a low speed whereby the boat may be used for trolling. It is contemplated that the outboard motor 2 be provided with a clutch arrangement whereby the propellor 12 may be disconnected from driving engagement with the internal combustion engine of the outboard motor.
As shown in FIG. 1 the attachment is in position to effect driving of the propellor I2. However, since the motor is pivoted to the bracket 14 on the axis at 26, the motor 24, tube 28 and driving member 32 may be swung upwardly and rearwardly to the position shown by dotted line in FIG. 1. In this position the driving member 32 is clear of the water and thus imposes no additional drag when a boat is being propelled by the outboard motor 2. To effect selective positioning and retention of the motor 24 and tube 28 in either of the two positions shown, a control lever 38 is provided.
The control lever 38 is pivoted, at 40, to a sub bracket 42 on one of the straps l6 and extends downwardly below the pivot 40. At its lower end the lever 38 is pivotally joined to a link 44 which extends to and is pivotally connected to a further bracket 46 on the tube 28. Obviously, when the handle 48 of lever 38 is swung rearwardly, the motor and transmission tube 28 are swung to the full line positions wehreas forward movement of the handle 48 will swing the motor and transmission tube to the dotted line position.
It is desirable to fixedly retain the swingable part of the attachement in either selected position and for this purpose a detent means is provided. The handle 48 is provided with a pushbutton 50 which operates, when depressed, through a rod 52 to swing a pawl 54 relative to the lever 38. The pawl 54 has a nose portion engageable in either of two notches 56 in the periphery of the bracket 42. Suitable spring means (not shown) are provided to urge the pawl 54 into engagement with an adjacent notch. Thus, the pawl serves to securely hold the attachment either in its operative position as shown in full lines or its retracted position shown in dotted lines.
The pushbutton and pawl arrangementjust described are merely illustrative of a manner in which locking may be effected and, obviously, many other means may be employed.
It is also within the scope of applicants invention to effect swinging movement of only the transmission tube 28. Such could be accomplished by pivoting the same to the electric motor 24, which in turn would be rigidly mounted on the bracket 14. This embodiment would require an axially disconnectible driving connection between the flexible shaft 30 and the drive shaft of the motor. However, such devices are well known and need not be described in greater detail.
While a single specific embodiment of the invention has been shown and described herein, the same is merely illustrative of the principles involved and other embodiments may be employed within the scope of the appended claims.
1. An attachment for an outboard motor having a propellor shaft, a generally upright housing for said propellor shaft and a rearwardly facing propellor journalled on said housing adjacent the lower end thereof, said attachment comprising:
bracket means adapted to be removably mounted on said housing above said propellor;
an electric motor on said bracket means; and
transmission means drivingly connected to said electric motor and having a driving member selectively engageable directly with said propellor exteriorly of said housing to drive the same in rotation, at least said transmission means being movably mounted on said bracket for selective movement between a first position whrein said driving member drivingly engages said propellor and a second position free of and above said propellor.
2. An attachment as defined in claim 1 wherein said transmission means comprises a substantially rigid tube pivotally mounted on said bracket means for swinging movement thereon and a drive shaft rotatable in said tube, said driving member being journalled in the end of said tube remote from said bracket means.
3. An attachment as defined in claim 2 wherein said tube, when in said first position, has a first portion extending generally vertical and a lower end portion directed toward the center of said propellor, said drive shaft being a flexible shaft device, said tube being pivotally mounted on said bracket means for swinging said lower end portion rearwardly and upwardly from said propellor.
4. An attachment as defined in claim 2 wherein said electric motor and said tube are fixedly secured together to swing as a unit.
5. An attachment as defined in claim 2 including selectively operable means for moving said transmission means to and holding the same in either said first or second position.