US3730127A - Propeller throttling device for boats - Google Patents

Abstract

A propeller throttling device for boats, wherein a pair of pivoted vanes are disposed rearwardly of a propeller in the water, such that the vanes may be in a position to follow the propeller and may be parallel therewith or at substantially right angles thereto, so that a powerful propeller may be throttled in a manner to permit trolling operation of a boat at low speed; said vanes being pivoted by rectilinearly operated cross head and linkage structure controlled remotely by flexible shaft and lever mechanism located in the hull of a boat; said propeller throttling device being particularly adapted for use in connection with powerful outboard motors. In order to maintain optimum performance at high speeds, the throttling device is provided with means to permit limited degrees of pivoting motion to more accurately follow the wake during turns. Additionally, a trim tab and/or a small trim plate is provided on one of the pivoted vanes in order to counteract the effects of the propeller-created pressure spiral impinging on the vane at high speed which otherwise adversely affects the steering of the watercraft.

Description

white States atet 1 Pedersen [4 1 May 1, 1973 PROPELLER THROTTLING DEVICE FOR BOATS [75] Inventor: Charles A. Pedersen, Phoenix, Ariz.

[73] Assignee: Rothmans of Pall Mall Canada Limited, Toronto, Ontario, Canada [22] Filed: May 13, 1971 [21] Appl. No.: 143,110

Related US. Application Data [63] Continuation-impart of Ser. No, 816,590, April 16,

1969, Pat. NO. 3,581,699.

UNITED STATES PATENTS 5/1893 Samohod ..114/145 R 6/1971 Pederson ..1 14/145 A Primary Examiner-Milton Buchler Assistant Examiner-Galen L. Barefoot Attorney-Drummond & Phillips [5 7 ABSTRACT A propeller throttling device for boats, wherein a pair of pivoted vanes are disposed rearwardly of a propeller in the water, such that the vanes may be in a position to follow the propeller and may be parallel therewith or at substantially right angles thereto, so that a powerful propeller may be throttled in a manner to permit trolling operation of a boat at low speed; said vanes being pivoted by rectilinearly operated cross head and linkage structure controlled remotely by flexible shaft and lever mechanism located in the hull of a boat; said propeller throttling device being particularly adapted for use in connection with powerful outboard motors. In order to maintain optimum performance at high speeds, the throttling device is provided with means to permit limited degrees of pivoting motion to more accurately follow the wake during turns. Additionally, a trim tab and/or a small trim plate is provided on one of the pivoted vanes in order to counteract the effects of the propellercreated pressure spiral impinging on the vane at high speed which otherwise adversely affects the steering of the watercraft.

3 Claims, 4 Drawing Figures Patented May 1, 1973 3,730,127

2 Sheets-Sheet 2 INVENTOR. CHARLES APEDERSON ATTORNEYS PROPELLER THROTTLING DEVICE FOR BOATS This application is a continuation-in-part of my copending application, Ser. No. 816,590, filed Apr. 16, 1969, for Propeller Throttling Device For Boats, said application Ser. No. 816,590 now being U.S. Pat. No. 3,581,699 to which reference is taken.

This invention relates to the watercraft control arts and, more particularly, to a propeller throttling device to permit the use of a powerful propeller during trolling operation of a boat at low speeds.

Sports marine equipment may be used for a variety of purposes, such as water skiing, fishing, cruising, and many other pleasurable activities.

A large comfortable watercraft normally requires very powerful propulsion means, including a powerful engine, and a propeller suitable for high speed operation and the delivery of a great amount of power. However, such a combination is not optimum for usein fishing, and particularly low speed operation of a boat for careful trolling operations. Many boat owners having substantial and comfortable boats have utilized powerful motors and appropriate propellers for high speed operation of such boats, and have found it necessary to employ an auxiliary and very small engine for fishing and particularly those lower speed operations where trolling is important and the speed of the boat is critical. The use and maintenance of a separate and secondary power unit has many disadvantages and maintenance, as well as initial cost problems. Additionally, auxiliary motors oftentimes are inconveniently located and mounted in connection with a highly desirable pleasure craft.

Such highly desirable pleasure crafts are roomy, they are fast in the water, they are generally luxurious and comfortable, and in order to enjoy all of these benefits, a suitable power unit and propeller must, of necessity, match the size and capabilities of such a boat. These characteristics, however, are certainly not suitable for low speed trolling which requires very critical speed control and very low speed operation of such a boat. Therefore, any person desiring to use such a watercraft and power combination for trolling most often fails to perform properly in order to troll successfully in a manner which will yield success in fishing for many species of fish.

The invention described in my above referenced copending application, Ser. No. 816,590, now U.S. Pat. No. 3,581,699 relates to propeller throttling device for boats which may conveniently be coupled to boats having powerful motors, and may be disposed rearwardly thereof below the water line, and in a manner such that the powerful motor and its respective propeller is not substantially compromised when operating a full power output and high speed, and whereby the rearward efflux of water may be throttled behind the propeller in order to prevent undue forward speed of the respective boat so that precise speed control may be attained compatible with trolling operations for various species of fish.

More specifically, the invention described in my above referenced copending application, Ser. No. 816,590, now U.S. Pat. No. 3,581,699, comprises novel means for mounting brackets above and below the axis of the propeller so that structural support and rigidity of the invention may be attained to handle installations in connection with a powerful motor and propeller installations, and whereby precise and proper angular control of the throttling vanes behind the propeller may be attained. The invention described in my above referenced co-pending application, Ser. No. 816,590, now U.S. Pat. No. 3,581 ,699, further comprises a novel cross head and guide rod and linkage mechanism coupled to a remotely controlled flexible shaft means, whereby a person in the cockpit of a boat may control the angular disposition of the hydrofoil vanes behind the motor drive propeller in order to throttle the rearward efflux of water from the propeller, and thereby foil its propulsive force, and thus control the speed of the boat in a manner compatible with trolling require ments when fishing for fish of various species.

While the throttling device described and claimed in Ser. No. 816,590, now U.S. Pat. No. 3,581,699, performs its low speed functions admirably, some modest problems associated specifically with high speed operation were encountered, and it is to the improvement of high speed operating characteristics of such a propeller throttling device that the present invention is directed.

-More specifically, it was found that during the negotiation of high speed turns, with a throttling device retracted, the vanes did not quite follow the wake of the boat and thus added a slightly misleading characteriStic in steering the boat. Similarly, because of the torque reaction exerted by powerful propellers, the spiral pressure wave moving rearwardly from the propeller also introduced somewhat undesirable high speed steering characteristics which varied to some extent in accordance with the propeller speed and also with the physical displacement between the throttling device and the propeller.

Accordingly, it is an object of the present invention to provide a propeller throttling device for boats which may be used in conjunction with very powerful engines and propellers for the purpose of controlling the speed thereof such that it will be compatible with operating under trolling conditions while still maintaining desirable high speed operating characteristics.

A more specific object of the invention is to provide a novel mounting means for such a propeller throttling device which permits the throttling device, when in its retracted position, to accurately follow the wake of a boat executing a high speed turn.

Still another object of this invention is to provide trim tabs and/or trim plates on one vane of the throttling device in order to counteract the torque reaction and effect of the high pressure spiral wave set up be hind the propeller during high speed operation.

The subject matter of the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, may best be understood by reference to the following description taken in connection with the accompanying drawing of which:

FIG. 1 is a fragmentary view illustrating the propeller supporting structure of a powerful outboard motor with the propeller throttling device of the invention fitted thereto;

FIG. 2 is a top view of the propeller throttling device of the present invention with the vanes thereof in the retracted position and showing a range of pivotal movement available to'the propeller throttling device with respect to the outboard motor which permits the throttling device to assume an optimum position with respect to the wake generated during a high speed turn;

FIG. 3 is a side view of the device of the present invention illustrating the disposition of torque correction trim tabs and plates which may be utilized singly or in combination according to the configuration of the specific unit to which the throttling device is attached; and

FIG. 4 illustrates the throttling device with the vanes in their extended positions as utilized during the trolling operation further illustrating the minimal effect of the trim tabs and/or trim plates in such position.

As shown in FIG. 1 of the drawing, a boat may be a substantially sized and very comfortable boat adapted to operate at high speed, and which may be powered by a very powerful motor 22 having sufficient power to tow several water skiers, if desired.

The motor 22, shown as an example only, is an outboard motor having a gear box portion 24 suspended rearwardly and below the stern 26 of the boat, and normally submerged below the water line 28, shown in FIG. 1 of the drawing.

Upper and lower brackets 30 and 32 secure the propeller throttling device of the invention to the gear box 24 which may be termed a propeller shaft support carrying a rotary impeller 34. The propeller throttling device of the invention carried by the brackets 30 and 32 is generally indicated at 36 in FIG. 1 of the drawing. Connected to this propeller throttling device is a flexible shaft mechanism 38 which extends to a manual control not shown in the drawing. One may refer to the previously referenced patent application, Ser. No. 816,590, now US. Pat. No. 3,581,699, for an exemplary manual control for fixing the position of the throttling device.

Details of the foregoing general features of the invention will be hereinafter described in connection with the several views and particular attention is immediately called to FIG. 1 of the drawing.

The bracket 30 is secured by bolts 42, 44, 46 and 48 which are also illustrated in FIG. 2 of the drawing. These bolts 42, 44, 46 and 48 extend through a horizontal plate portion 50 which is generally integral with the gear box structure 24 of the motor 22. This gear box structure 24, according to the terminology herein, shall be considered as a propeller shaft support and may be considered equivalent to structure at the stern of a boat from which any propeller is mounted in rotary relationship with a journalled shaft.

The bracket 32 is secured by a plurality of bolts 52, to a downwardly projecting portion 54 generally integral with a lower portion of the propeller gear box portion 24 of the engine 22.

A vane supporting shaft 56 is secured by conventional screw threaded nut 58 to the lower bracket 32, this being the lower end of the shaft 56, and the upper end of the shaft 56 passes through the upper bracket 30 with clearance and is secured to a second, rearwardly extending upper bracket 31 by means of a suitable screw threaded nut 60. The shaft 56 is generally maintained in a vertical disposition and it is generally close to an intersection with the axis of the rotary propeller 34.

Loop-shaped Teflon line antifriction bearings 61, 62, 64 and 66 are connected to a first hydrofoil vane 68 which pivots about the axis of the shaft 56. Similar bearings 70, 71, 72 and 74 are secured to a second hydrofoil vane 76 so that both the vanes 68 and 76 are pivoted about the axis of the shaft 56 and may assume a position, as shown in FIG. 2, wherein the vanes 68 and 76 are substantially parallel with the axis of the propeller 34 and offer slight resistance to the flow of water relative thereto. The vanes 76 and 68 may be at an intermediate angular disposition to the axis of the propeller 36, and as shown in FIG. 4, the vanes 76 and 68 may be pivoted into a position at substantially right angles to the axis of the propeller 34, all as will be hereinafter described in detail.

As shown in the several Figures, and particularly in FIG. 3, the bracket 30 terminates just aft of the shaft 56. The shaft 56 extends upwardly through the bracket 30 and through the second, rearwardly extending bracket 31 which carries the upstanding brackets 78 and 80. These brackets 78 and 80 support guide rods 82 and 84 which are generally horizontally disposed and in a substantially parallel relation to the axis of the propeller 34. Slidably mounted on these guide rods 82 and 84 is a cross head 86 which carries a ball bearing member 90 which serves as a pivotal connection for a link 96 which is coupled to a flexible cable 116. The cable l16 is slidably mounted in a flexible sheath 118 having its rear terminal axially restrained in a stationary fixture 120 mounted at the forward end of the bracket 31. The flexible cable 116 and the sheath 118 comprise the flexible cable mechanism 38 hereinbefore described.

Links 100 and 102 are pivotally secured to the cross head 86 on opposite sides of the bearing member 90 by means of bolts 88 and 92. The links 100 and 102 extend forwardly and slightly downwardly to respective vanes 76 and 68 at which their forward terminals are pivotally secured to respective flanges and 111 of the vanes 76 and 68. Thus, as perhaps best shown in FIG. 4, the hydrofoil vane 68 is provided with a flange 111 through which a bolt 108 pivotally secures the forward end of the link 102 and, similarly, a bolt 109 pivotally secures the link 100 to the flange 110 or the vane 76.

Thus, as the flexible cable 116 is manually actuated to move the cross head 86 forwardly and rearwardly, as guided by the guide rods 82 and 84, the hydrofoil vanes 76 and 68 may assume the fully retracted position shown in FIGS. 1, 2, and 3, the fully extended position shown in FIG. 4, or any intermediate position through the linkage coupling the position of the cross head 86 to the flanges 110 and 111 by means of the links 100 and 102.

As best shown in FIGS. 2 and 4, the bracket 30,

which is fixed to the horizontal plate portion 50 which is integral with the gear box 24 of the motor 22, is pivotally fixed to the vane supporting shaft 56 to afford the entire throttling apparatus 36 a limited degree of pivotal motion when the vanes 68 and 76 are in the retracted position. This range of pivotal motion is illustrated in FIG. 2 with one extreme position of the bracket 30 shown in solid lines and the other extreme shown in dashed lines. Referring to both FIG. 2 and 4, it will be observed that the bracket 30 is provided with rearwardly disposed stops 113 and 115 which impinge on corresponding shoulder portions 117 (see FIG. 4) of rearwardly extending flange 31. This degree of pivotal freedom with the vanes in the retracted position may approximate an exemplary maximum of plus or minus in order that the propeller throttling device 36 is enabled to follow the wake of the boat when operated at high speed and thus contribute no steering effect of its own. It will be understood, of course, that the bracket is fixed to the plate 50 such that the range of motion depicted in FIG. 2 represents the available motion between the throttling device 36 and the propeller 34.

As previously indicated, the effect of a powerful propeller functioning at high speed with the vanes 68 and 76 in the retracted position (as they must be for high speed operation) brings about a torque reaction as a result of the spiral pressure wave impinging upon the retracted vanes. Inasmuch as this reaction also contributes to the overall steering experienced at high speeds, it is desirable to compensate for this effect to cancel its contribution such that steering is, in effect, neutral or natural to the operator. For those installations in which the propeller throttling device 36 is positioned within a few inches, typically 3-6 inches of the propeller, a simple compensating tab 121 affixed to the vane 68 to intercept the spiral pressure wave has been found to provide adequate compensation by converting a small portion of the spiral pressure wave into side thrust. The vane on which the compensating tab 121 is located is, of course, a function of the direction of propeller rotation and pitch which is, however, quite standard.

It has been found, however, that for those few types of installations in which the propeller 34 is disposed several additional inches forward of the propeller throttling device 36, whereby the spiral pressure wave has a sufficient axial distance to rotate further, a trim plane 123 may advantageously be disposed on the outer rear surface of the vane 68 as shown in FIGS. 1, 3, and 4. The trim plane 123 preferably takes the form of an elevated crosspiece 125 supported at its upper and lower ends by wedge shaped support members 126 and 127. The wedge shaped support members 126 and 127 have their higher ends facing forward such that the horizontal crosspiece 125, which functions as the trim plane, is slanted inwardly toward the rear. Thus, the opening defined by the wedge shaped support members 126 and 127 and the horizontal crosspiece 125 is larger at their forward edges than that at their rear edges. With certain types of installations, it may be desirable to utilize both the trim tab 121 and the trim plate 123 to achieve effectively neutral high speed steering characteristics with the propeller throttling device of the invention coupled to the boat.

While the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, materials, and components, used in the practice of the invention which are particularly adapted for specific environments and operating requirements without departing from those principles.

I claim:

1. In a propeller throttling device for boats having: a

r0 eller shaft su ortin structure; a rotar ro eller proiecting therefr iii; a p air of plate-like va ii s heaving hydrofoil surfaces disposed behind said propeller and pivoted relative to said supporting structure; axis means pivotally mounting said vanes; said axis means disposed at an angle to the rotary axis of said propeller and disposed rearwardly therefrom and close to intersecting alignment with the axis of said propeller; first and second bracket means secured to said supporting structure respectively above and below the rotary axis of said propeller, said first bracket means being disposed above the axis of said propeller; guide rod means spaced apart and generally parallel to the axis of said propeller; a cross head slidably mounted on said guide rods, and links pivotally connected to said cross head and said vanes; means for pivoting said vanes from positions in which said hydrofoil surfaces are substantially parallel to the axis of said propeller and at an angle to said axis of said propeller; said means for pivoting said vanes comprising a flexible push-pull cable means coupled to said cross head for actuating said linkage and said vanes; and a multi-purpose control means remote from said cross head and coupled to said flexible push-pull cable means;

the improvement comprising: a third bracket means overlapping and disposed generally aft from said first bracket means, said third bracket means supporting said guide rods; said axis means being pivotally mounted on said first bracket means such that said vanes may pivot with respect to said first bracket means, said first bracket means having rearwardly extending tabs on each side thereof oriented to abut said third bracket means thereby affording limited pivotal freedom of said axis means with respect to said first bracket means whereby said propeller throttling device is free to follow the wake of the boat during maneuvers when said vanes are retracted.

2. The propeller throttling device of claim 1 which includes an affix to one of said vanes for intercepting a portion of the spiral pressure wave from said propeller to provide a side thrust compensating the natural side thrust brought about by the effect of the spiral pressure wave on the propeller throttling device during high speed maneuvering.

3. The propeller throttling device of claim 2 in which said affix comprises a tab extending directly forwardly from the said vane to which it is fixed when said propeller throttling device is in the fully retracted position.

Claims (3)

1. In a propeller throttling device for boats having: a propeller shaft supporting structure; a rotary propeller projecting therefrom; a pair of plate-like vanes having hydrofoil surfaces disposed behind said propeller and pivoted relative to said supporting structure; axis means pivotally mounting said vanes; said axis means disposed at an angle to the rotary axis of said propeller and disposed rearwardly therefrom and close to intersecting alignment with the axis of said propeller; first and second bracket means secured to said supporting structure respectively above and below the rotary axis of said propeller, said first bracket means being disposed above the axis of said propeller; guide rod means spaced apart and generally parallel to the axis of said propeller; a cross head slidably mounted on said guide rods, and links pivotally connected to said cross head and said vanes; means for pivoting said vanes from positions in which said hydrofoil surfaces are substantially parallel to the axis of said propeller and at an angle to said axis of said propeller; said means for pivoting said vanes comprising a flexible pushpull cable means coupled to said cross head for actuating said linkage and said vanes; and a multi-purpose control means remote from said cross head and coupled to said flexible push-pull cable means; the improvement comprising: a third bracket means overlapping and disposed generally aft from said first bracket means, said third bracket means supporting said guide rods; said axis means being pivotally mounted on said first bracket means such that saId vanes may pIvot with respect to said first bracket means, said first bracket means having rearwardly extending tabs on each side thereof oriented to abut said third bracket means thereby affording limited pivotal freedom of said axis means with respect to said first bracket means whereby said propeller throttling device is free to follow the wake of the boat during maneuvers when said vanes are retracted.

2. The propeller throttling device of claim 1 which includes an affix to one of said vanes for intercepting a portion of the spiral pressure wave from said propeller to provide a side thrust compensating the natural side thrust brought about by the effect of the spiral pressure wave on the propeller throttling device during high speed maneuvering.

3. The propeller throttling device of claim 2 in which said affix comprises a tab extending directly forwardly from the said vane to which it is fixed when said propeller throttling device is in the fully retracted position.

Images