Patent Publication Number: US-6220195-B1

Title: Trolling plate with improved force transmission linkage

Description:
TECHNICAL FIELD 
     The present invention relates to trolling plate assemblies for use with motorized watercraft, and more particularly relates to such an assembly wherein a robust linkage exists between the outdrive bracket and the thrust regulating plate. 
     BACKGROUND OF THE INVENTION 
     With recent advances in material science, and the consumer driven desire for larger and more powerful engines, recreational fishing vessels presently have more available power output than at anytime in the past. These vessels, however, are still used for trolling when fishing for certain types of game fish. As a consequence, unless a separate trolling motor is installed on the vessel, the primary propulsion system must be used. However, depending upon engine output and prop configuration, a desirable trolling speed of between 1.5 and 5 knots is often times impossible. Therefore, operators of such vessels must install a thrust mitigating device to decrease the propulsion efficiency of the watercraft. This device is generally referred to as a trolling plate. 
     Trolling plates are generally a structure that is attached to the secondary drive components of outboard or outdrive systems, usually by way of the anti-cavitation plate. These structures then are positioned directly in the thrust path of the prop, thereby reacting with the volume of water displaced by the prop in a rearward direction. As a consequence of placing the trolling plate in a trolling position and operating the drive system at idle or low speed, the propulsion system becomes inefficient, thereby decreasing the speed of the vessel. 
     Conventional trolling plates such as THE HAPPY TROLLER sold by Idea Development Company of Sequim, Washington, essentially rely on a mounting bracket attached to the secondary drive unit that has at its aft end a rotationally linked thrust reaction plate. The plate has an upper U-shaped portion that is adapted to receive a shaft horizontally and laterally positioned in the bracket. Slightly forward of this shaft is a spring loaded selector bar that selectively engages notch pairs formed in the U-shaped portion of the plate. This selector bar extends through the bracket so that when the plate reacts on the selector bar via the notches, it transmits forces to the bracket via the holes in the bracket that supports the selector bar. 
     While the described structure accomplishes the intended purpose of transmitting thrust forces from the prop to the drive unit, it does so via notches and holes formed in sheet material, usually aluminum, that may become worn over time, and are especially subject to excessive wear and potential failure when presented with high force thrusts that may emanate from high output engines or accidental over revving. It is thus desirable to have a trolling plate that is adapted to fit the secondary drive unit of an outboard or inboard/outboard drive system, but wherein thrust forces from the prop are transferred to the drive system by distinct linkages as opposed to using a notched plate to bracket to outdrive means. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a trolling plate assembly that provides a user with the option of establishing a trolling position or a non-trolling position when the invention is mounted to a drive or outdrive unit of a water craft. Unlike traditional trolling plate assemblies, the present trolling plate assembly provides a robust linkage between an outdrive bracket and a thrust regulating plate pivotally mounted to the bracket. More particularly, the outdrive bracket has an upper surface, a lower surface, a forward portion, and a rear portion, and defines a passage at the rear portion from the upper surface to the lower surface. The thrust regulating plate, as previously noted, is pivotally linked to the outdrive bracket at the rear portion thereof wherein the plate is positionable to establish a trolling position that diminishes the effective thrust of the drive unit and a second position, wherein the thrust regulating plate has a first surface that faces at least partially towards the drive unit when in the trolling position, and a second opposing surface. 
     A selector subassembly comprising a user operable linkage is located at the passage and partially extends therethrough. The selector subassembly operates to selectively obstruct rotational movement of the thrust regulating plate. When selected to obstruct rearward rotational movement of the thrust regulating plate, forces presented to the regulating plate are transmitted to the outdrive bracket though the linkage. The selector subassembly may, but need not, positively engage a plate subassembly mounted to the first surface of the thrust regulating plate, as it need only contact the plate subassembly when the same is caused to pivot upon exposure to thrust created by the drive unit. The plate subassembly generally comprises a protruding member adapted to selectively engage or otherwise contact the user operable linkage. 
     It is to be understood that the invention concerns the establishment of a force transmitting linkage between the outdrive bracket and the thrust regulating plate that does not rely upon slots or notches in either the outdrive bracket or the thrust regulating plate. Thus, alternative embodiments may include the use of a plunger (spring-biased or gravity-biased) that depends from the upper surface of the bracket and selectively engages an ancillary structure affixed to the thrust regulating plate. When in the extended position, it contacts the ancillary structure by obstructing the free rotation thereof when the thrust regulating plate is in the trolling position, and when in the retracted position, permits free rotation of the thrust regulating plate from the trolling position. 
     Features of the invention include the incorporation of a selector bar for positively establishing the second position as has been done previously in the prior art. In a preferred form, the rear portion of the outdrive bracket includes a pair of upturned portions, each defining a slot, and the selector subassembly further comprises a selector bar disposed in the opposed slots and linked to the bracket by at least one biasing member wherein the selector bar is locatable in a portion of the thrust regulating plate when the same is in the second position. The user will then operate the selector bar to engage and disengage the thrust reaction plate into and from the non-trolling position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective elevation view of the trolling assembly showing the relative positions of the outdrive bracket and thrust regulating plate; 
     FIG. 2 is a partial perspective view of the trolling assembly of FIG. 1 wherein the selector subassembly is detailed; 
     FIG. 3 is a side elevation view of the trolling assembly of FIG. 1; 
     FIG. 4 is a partial cross-sectional view of the trolling assembly shown in FIG. 1 taken substantially along the lines  4 — 4  shown therein; 
     FIG. 5 is a similar cross-sectional view to that of FIG. 4 but the selector subassembly is shown in the active state and further details the engagement and disengagement of the selector subassembly from the plate subassembly; 
     FIG. 6 is a side elevation view of the trolling assembly when in a trailing state; 
     FIG. 7 is an elevation view of the trolling assembly detailing the various components of the selector subassembly and plate subassembly; and 
     FIG. 8 is an elevation view similar to that of FIG. 4 but wherein a plunger linkage is used to prevent rearward rotation of the plate subassembly. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     Turning then to the several Figures wherein like numerals indicate like parts, and more particularly to FIGS. 1 and 2, trolling assembly  10  is best shown, and unless otherwise indicated, all components are constructed of high-quality stainless steel and aluminum. Trolling assembly  10  has four major components, namely outdrive bracket  20 , thrust regulating plate  40 , selector subassembly  60  (FIG.  4 ), and plate subassembly  90  (FIG.  4 ). Outdrive bracket  20  is preferably formed from a single piece of {fraction (3/16)}″ thick aluminum and is formed to include horizontal portion  22  and vertical portions  32 . Horizontal portion  22  defines holes  24 , which receive bolts (not shown) to facilitate attachment of trolling assembly  10  to the anti-cavitation plate of an outdrive. Vertical portions  32  defined slots  36  to receive selector bar  54 , and a pair of holes to receive pivot shaft  52 . Thrust regulating plate  40  is also constructed of {fraction (3/16)}″ thick aluminum, and has holes formed therein to receive nut and bolt combinations  88  in main portion  42  and pivot shaft  52  in return portions  46 . Return portions  46  also defined a pair of notches  50  that selectively receive portions of selector bar  54  as will be shown below. 
     As best shown in FIG. 2, thrust regulating plate  40  is pivotally attached to outdrive bracket  20  by way of pivot shaft  52 . Thrust regulating plate  40  is biased to the trolling positioned as shown in FIG.  1  through torsion springs  58 . As clearly illustrated in FIG. 2, torsion spring ends  59   a  press upon the upper portion of main portion  42 , and torsion spring ends  59   b  press upon horizontal portion  22 . The result of these forces causes rotation of thrust regulating plate  40  to achieve a trolling position. 
     Momentarily referring to FIG. 6, it can be seen that when thrust regulating plate  40  is in the non-trolling position, springs  56  cause selector bar  54  to locate in notches  50 . In this manner, thrust regulating plate  40  will not pivotally move relative to outdrive bracket  20  unless a mechanical force sufficient to overcome the spring-biased retention of selector bar  54  in notch  50  is presented via handle  64 . 
     Discussion will now be directed to selector subassembly  60  and plate subassembly  90 . Referring to FIGS. 3 and 4, thrust regulating plate  40  is shown in the locked trolling position. In this position, selector bar  54  is not utilized. Instead, selector subassembly  60 , which includes U-shaped bar  62 , springs  34 , handle  64 , linking bar  66 , elliptical member  68 , and dog  70 , interacts with plate subassembly  90 . As will be described in more detail below, all thrust forces generated by the watercraft&#39;s propeller against thrust regulating plate  40  will be transmitted to outdrive  20  through robust structural members. As briefly described above, selector subassembly  60  includes U-shaped bar  62  which is disposed in slots  30  (shown in FIGS. 2 and 7) formed in horizontal portion  22  to which is attached handle  64 . Linked to handle  64  is linking bar  66  having affixed thereto elliptical member  68 . Washer  65  is affixed to handle  64 , and interacts with elliptical member  68 . In this manner, handle  64  and U-shaped bar  62  are prevented from dropping further into slots  30 . Linking bar  66 , which is disposed in slot  26  defined by horizontal portion  22 , includes pin  67  for associating linking bar  66  with dog  70 . In turn, dog  70  is rotationally linked with brackets  82   a  and  82   b  by way of pin  86 . As a consequence of this configuration, when an upward force is presented to linking bar  66 , dog  70  is caused to rotate about pin  86 . The upward forces are generated by the interaction of elliptical member  68  contacting with U-shaped bar  62  as it drops down along handle  64 . 
     Dog  70  acts as an intermediary between movable plate subassembly  90  and fixed outdrive bracket  20 . As shown in FIG. 4, any thrust presented against thrust regulating plate  40  will cause a rearward force to be presented upon surface  76  of dog  70 . This rearward force is then transmitted via dog  70  to horizontal portion  22  of outdrive bracket  20  at the interface of surface  80  of dog  70  and the lower portion of horizontal portion  22 . When it is desired to disengage from the trolling position, handle  64  is pivotally rotated upwardly as best shown in FIGS. 5 and 6. In so doing, the tension bias of springs  34  on U-shaped bar  62  is overcome, and U-shaped bar  62  presses against and causes selector bar  54  to move to the forward portion of slots  36 . Simultaneously, dog  70  is rotated about pin  86  thereby displacing dog  70  from plate  98 . Once plate  98  is free from interference with surface  76  of dog  70 , thrust applied against thrust regulating plate  40  by the watercrafts propeller causes outward rotation of thrust regulating plate  40 , whereafter tension exerted by springs  56  causes bar  54  to locate in notches  50  when thrust regulating plate  40  achieves the trailing position. 
     To establish a trolling position, handle  64  is pivoted towards the watercraft, thereby disengaging selector bar  54  for from notches  50 , whereafter torsion springs  58  cause the inward or downward rotation of thrust regulating plate  40  to the trolling position. Because linking bar  66  exerts no downward bias upon dog  70  apart from gravitational forces, surface  78  of dog  70  is capable of riding up and over the upper portion of plate  98  until dog  70  achieves the position shown in FIG.  4 . 
     While the embodiment set forth in FIGS. 1-7 illustrates the preferred embodiment, alternative forms also exist. In FIG. 8, the robust selector subassembly  60  is modified so that a single plunger  100  is disposed in slot  26  to thereby selectively engage plate  98 . To provide a sufficient structure to transfer shear forces presented to plunger  100  to bracket  20 , collar  102  is fixedly attached to horizontal portion  22 . Depending upon design considerations, it is equally appropriate to locate collar  102  on the underside of horizontal portion  22 . To disengage plunger  100  from plate subassembly  90 , the user need only lift plunger  100  as indicated by the arrow. To facilitate engaging operations of is plunger  100 , plate  98  may be sloped as illustrated thereby creating a ramp so that plunger  100  will naturally elevate when thrust regulating plate  40  is permitted to rotate into the trolling position.