Patent Publication Number: US-8974260-B1

Title: Cutter assembly for a motor propeller

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     None. 
     REFERENCE TO A MICRO-FICHE APPENDIX 
     None. 
     TECHNICAL FIELD 
     The present invention relates generally to the field of boat motor propellers and, more specifically, to an electric trolling motor housing which includes a plurality of blades to cut underwater growth before the underwater growth can wrap around the propeller and stop or damage the propeller motor. 
     STATEMENT REGARDING COPYRIGHT/TRADEMARK 
     At least a portion of the disclosure of this document may contain material, which is subject to copyright/trademark protection. The copyright/trademark owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright/trademark rights whatsoever. 
     BACKGROUND OF THE INVENTION 
     Fresh water sport fishing has grown immensely in sophistication and popularity. The sporting pursuit of gamefish has become a profession to many and an extensive hobby with a large portion of the populace. These gamefish tend to concentrate around cover in the water, and often the thicker the cover, more and larger gamefish. Cover is considered to be any of a variety of things, either natural or manmade, in the water which serve to hide or protect the fish in their aquatic environs. One of the thickest forms of cover is grass particularly in more southern parts of the country. Many species of grass exist in natural and manmade lakes, and the grass in many cases can become so thick as to make navigation difficult or impossible. 
     Because underwater grass is such an excellent cover for fish that anglers often seek to enter even the thickest grass bed in pursuit of trophy gamefish. 
     An essential accessory on most sport fishing boats is a small, electric motor which is used to maneuver the boat during the fishing. These motors are commonly referred to as trolling motors to distinguish them from the combustion engines which are the primary power for the boat. Trolling motors are quiet and efficient, typically operated by batteries in the boat, and are far more effective during fishing than the larger and powerful combustion engines which are usually used for travel over greater distances. Such electric trolling motors are often mounted on the bow of the boat for use, and steered either by hand or by foot. Indeed, such trolling motors may be used by the fisherman without stopping his fishing or without taking his line out of the water. 
     Indeed, such electric trolling motors are frequently the only type of motors permitted on numerous small fishing lakes, as these motors permit the boat to travel around the lake, but with almost no wake or noise. 
     One of the disadvantages of electric trolling motors, however, is the fact that the propellers can be quickly tangled with underwater growth, including grasses, to the point where the motor does not have enough power to turn propellers or the trolling motor seizes and is ruined. This is a particularly problem in lakes where grass grows thickly year round. In order for an electric trolling motor to operate efficiently, it must have a continuous flow of water. The thick grass cover blocks this flow, thereby preventing the motor from functioning properly or efficiently. 
     When the disruptions or failures occur to the electric trolling motor during the sport of game fishing valuable contest time limits are lost in trying to rectify the trolling motor issues. There are additional personal safety and property damage concerns when a sport game fishing boat is rendered powerless in wake or choppy water conditions. 
     Thus, there is a need for an improved cutter assembly for a motor propeller that can be easily manufactured, assembled, and effectively used to increase sport game fishing safety and enjoyment. 
     An objective of an embodiment of the cutter assembly for a motor propeller is to provide protection for an electric trolling motor that works in any electric trolling motor direction. 
     Yet another objective of an embodiment of the cutter assembly for a motor propeller is to provide protection for an electric trolling motor that draws grass towards the cutting assembly. 
     Another objective of an embodiment of the cutter assembly for a motor propeller is to provide protection for an electric trolling motor which includes improved cutting blade orientation with respect to the propulsive effects of an electric trolling motor propeller. 
     A further objective of an embodiment of the cutter assembly for a motor propeller is to provide protection for an electric trolling motor that allows maneuvering through thick vegetative underwater cover. 
     Yet a further objective of an embodiment of the cutter assembly for a motor propeller is to provide protection for an electric trolling motor that can be quickly adapted to existing electric trolling motors, and quickly removed from the same for maintenance or when a trolling motor is not needed. 
     Another objective of an embodiment of the cutter assembly for a motor propeller is to provide protection for an electric trolling motor which includes quick release cutting blades. 
     DISCLOSURE OF INVENTION 
     The cutter assembly for a motor propeller works in conjunction with the propeller&#39;s propulsion to cut aquatic vegetation and deflect the cut vegetation from the operation of the propeller blade. An embodiment of the cutter assembly provides cover halves with external surfaces and internal surfaces sized to fit around a cylindrical motor housing. The cover halves are joined one to the other by at least one top lift off hinge and at least one releasable bottom releasable external fastener. The hinge(s) and fastener(s) allow the cover halves to open and receive the cylindrical motor housing, to close around the cylindrical motor housing, and to lock onto the cylindrical motor housing. The locked halves provide a cylindrical cover around the cylindrical motor housing. 
     In Four equal sized curved cutting blades each having dual cutting edges, a cutting blade surface having a concave portion, and a cutting blade surface having a convex portion are spaced equidistant around the cylindrical cover at equal distance from the cylindrical cover end proximate to the propeller. These curved cutting blades are attached to the external surface of the cylindrical cover such that each cutting blade is ninety degrees from its adjacent cutting blades with respect to a longitudinal central axis of the cylindrical cover. The orientation of each cutting blade is forty-five degrees from an axis orthogonal to the cylindrical cover longitudinal central axis, such that each cutting blade surface having a concave portion faces the cover forward end, and such that each cutting blade surface having a convex portion faces the cover end proximate to the propeller. 
     An alternative embodiment provides the four curved cutting blades each having dual cutting edges, a cutting blade surface having a concave portion, and a cutting blade surface having a convex portion are spaced equidistant around the cylindrical motor housing. These curved cutting blades are attached to the external surface of the cylindrical motor housing such that each cutting blade is ninety degrees from its adjacent cutting blades with respect to a longitudinal central axis of the cylindrical motor housing. The orientation of each cutting blade is forty-five degrees from an axis orthogonal to the cylindrical motor housing longitudinal central axis, such that each cutting blade surface having a concave portion faces the cylindrical motor housing forward end, and such that each cutting blade surface having a convex portion faces the cylindrical motor housing end proximate to the propeller. 
     As configured, the cutter assembly for a motor propeller cuts the vegetation drawn across and transverse to the curved cutting blades by the propulsion of the trolling motor propeller. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  depicts a perspective view of boat  200  having an electric trolling motor that provides a cylindrical motor housing  100  equipped with an embodiment of an improved cutter assembly  10  for a motor propeller  102  that allows maneuvering through thick vegetative underwater cover  300  without the vegetation wrapping around the propeller. 
         FIG. 2  depicts a perspective view of the cylindrical motor housing  100  of  FIG. 1  with an embodiment of an improved cutter assembly  10  for a motor propeller  102  attached to the cylindrical motor housing  100 , and providing four cutting blades  60 . 
         FIG. 3  depicts a perspective view of an embodiment of an improved cutter assembly  10  for a motor propeller  102  and at least one gasket  34  being fitted onto the cylindrical motor housing  100  of  FIG. 2  before the improved cutter assembly  10  is positioned around and locked onto the cylindrical motor housing  100 . 
         FIG. 4  depicts a perspective detail view of lift-off type hinge assembly  40  for the embodiment of an improved cutter assembly  10  for a motor propeller  102  of  FIG. 3 , showing the hinge assembly connecting cover halve  12  top edges. 
         FIG. 5  depicts a perspective detail view of off the lift-off type hinge assembly  40  of  FIG. 4  for an embodiment of an improved cutter assembly  10  for a motor propeller  102  showing the disconnected hinge assembly  40  on separated cover halves  12  top edges. 
         FIG. 6  depicts a perspective detail view of a fastener assembly  50  for an embodiment of an improved cutter assembly  10  for a motor propeller  102  of  FIG. 3 , showing the fastener assembly  50  connecting cover halve  12  bottom edges. 
         FIG. 7  depicts a perspective detail view of off the fastener assembly  50  of  FIG. 6  for an embodiment of an improved cutter assembly  10  for a motor propeller  102  showing the disconnected fastener assembly  50  on separated cover halves  12  bottom edges. 
         FIG. 8  depicts an exploded perspective view of an embodiment of an improved cutter assembly  10  for a motor propeller  102  showing the closing motion of the cutter assembly  10  about at least one top side hinge assembly  40 , and the locking of the cutter assembly  10  together by at least one bottom side locking assembly  50 , whereby four cutting blades  60  are attached to the cylindrical cover  20  external surface  26  such that each cutting blade  60  is equidistant from adjacent cutting blades  60  with respect to the cylindrical cover  20  longitudinal central axis  24 . 
         FIG. 9  depicts a planar end view of the cylindrical cover  20  and the cutting blade  60  attachment thereto for an embodiment of the improved cutter assembly  10  for a motor propeller  102  of  FIG. 8 , depicting that each cutting blade  60  is ninety degrees from adjacent cutting blades  60  with respect to the cylindrical cover  20  longitudinal central axis  24 , and that each cutting blade  60  is forty-five degrees from an axis orthogonal to the longitudinal central axis  24 . 
         FIG. 10  depicts a planar side view of a cutting blade  60  attached to the exterior surface  26  of the cylindrical cover  20  of  FIG. 9  taken at “ 10 - 10 ” for an embodiment of the improved cutter assembly  10  for a motor propeller  102  having vertically disposed motor propeller  102  blades, where the angle of the cutting blade tip end is parallel to the pitch of the blades of the motor propeller, and that for vertically disposed motor propeller blades, the cutting blade tip end is orthogonal to the cylindrical cover  20  longitudinal central axis  24 , e.g.,  FIG. 3 . 
         FIG. 11  depicts a cross section of  FIG. 12  taken at “ 11 - 11 .” 
         FIG. 12  provides a representative detail of a cutting blade  60  fastener attachment assembly  80  to the exterior surface  26  of the cylindrical cover  20  for an embodiment of the improved cutter assembly  10  for a motor propeller  102 . 
         FIG. 13  depicts an exploded perspective view of a representative detail for an alternative quick release cutting blade  60  attachment assembly  70  to the exterior surface  26  of the cylindrical cover  20  for an embodiment of the improved cutter assembly  10  for a motor propeller  102 . 
         FIG. 14  depicts a perspective view of the alternative quick release cutting blade  60  attachment assembly  70  of  FIG. 13 , whereby the cutting blade  60  is positionally fitted onto support posts  72  on the cylindrical cover  20  exterior surface  26  for the embodiment of the improved cutter assembly  10  for a motor propeller  102 . 
         FIG. 15  depicts a perspective view of the alternative quick release cutter blade  60  attachment assembly  70  of  FIG. 14 , whereby the positionally fitted cutting blade  60  support base  65  is locked onto the support posts  72  on the exterior surface  26  of the cylindrical cover  20  for an embodiment of the improved cutter assembly  10  for a motor propeller  102  of  FIG. 14  by a sliding locking plate  76  having spring elements sized to receive and secure the support post  72  caps  74 . 
         FIG. 16  depicts a perspective view of a cylindrical motor housing  100  with an embodiment of an improved cutter assembly  110  for a motor propeller  102  directly attached to the cylindrical motor housing  100 , whereby four cutting blades  160  are attached to the cylindrical motor housing  100  external surface such that each cutting blade  160  is equidistant from adjacent cutting blades  160  with respect to the cylindrical motor housing  100  longitudinal central axis  24 . 
         FIG. 17  is a detailed view of the embodiment of an improved cutter assembly  110  of  FIG. 16  taken at “ 17 - 17 .” 
         FIG. 18  is a detailed view of the embodiment of an improved cutter assembly  110  of  FIG. 16  taken at “ 18 - 18 .” 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Referring now to  FIGS. 1-18 , embodiments of an improved cutter assembly  10  or  110  for a motor propeller  102  are illustrated and disclosed. 
     An embodiment of the cutter assembly  10  for a motor propeller  102  includes cover halves  12  having external surfaces  14  and internal surfaces  16  sized to fit around a cylindrical motor housing  100 ,  FIGS. 1-3 . The cover halves  12  are joined one to the other by at least one top hinge assembly  40  and at least one bottom releasable external fastener assembly  50 ,  FIGS. 4-9 . This joinder of the cover halves  12  allows the cover halves  12  to open and receive the cylindrical motor housing  100 , to close around the cylindrical motor housing  100 , and lock onto the cylindrical motor housing  100 ,  FIGS. 1-3 ,  8  and  9 . Thus, the locked cover halves  12  form a cylindrical cover  20  around the cylindrical motor housing  100 ,  FIGS. 1-3 . The cylindrical cover  20  defines a longitudinal central axis  24 ,  FIGS. 2 and 8 , and includes a cylindrical cover top side opening  22  comprising a diameter large enough to receive a vertically disposed shaft  104  attached to a top side of the cylindrical motor housing  100 ,  FIGS. 2 ,  3  and  8 . As depicted in  FIG. 2 , the cylindrical cover  20  longitudinal central axis  24  corresponds to the longitudinal central axis of the cylindrical motor housing  100 . The cylindrical cover  20  further provides an internal surface  28 , an external surface  26 , a forward end  30 , and an aft end  32  proximate to the motor propeller  102 ,  FIGS. 2 ,  3  and  8 . 
     The embodiment of the cutter assembly  10  for a motor propeller  102  also includes four equal sized cutting blades  60 . Each cutting blade  60  provides a pair of cutting edges  63  positioned on either side of a cutting blade surface  64  having a concave portion, and cutting blade surface  62  having a convex portion. The cutting blade  60  surface  64  and surface  62  taper to a cutting blade tip end. For an embodiment of the cutter assembly  10  for a motor propeller  102  having blades with a ninety degree or vertical pitch relative to the longitudinal central axis  24 ,  FIGS. 8-10 , the cutting blade surfaces,  62  and  64 , and the cutting edges  63  at the cutting blade tip end are orthogonal to the longitudinal central axis  24 . The cutting blades  60  are spaced equidistant around the cylindrical cover  20  external surface  26 , such that each cutting blade  60  cutting edge  63  is disposed transverse to a plane rotated around the longitudinal central axis  24 . The cutting blades  60  are attached to the cylindrical cover  20  external surface  26  at equal distance from the cylindrical cover  20  aft end  32  proximate to the motor propeller  102 . The cutting blades  60  likewise are attached to the cylindrical cover  20  external surface  26  such that each cutting blade  60  is ninety degrees from adjacent cutting blades  60  with respect to the cylindrical cover  20  longitudinal central axis  24 . In this manner, the orientation of each cutting blade  60  is forty-five degrees from an axis orthogonal to the cylindrical cover  20  longitudinal central axis  24 ,  FIG. 9 . Each cutting blade  60  surface  64  having a concave portion faces the cylindrical cover  20  forward end  30 . Each cutting blade  60  surface  62  having a convex portion faces the cylindrical cover  20  aft end  32  proximate to the motor propeller  102 . 
     Testing indicates the optimum cutting effectiveness from propeller propulsion is attained when the angle of the cutting blade tip end is parallel to the pitch of the blades of the motor propeller  102 . As shown in  FIG. 10 , for vertically disposed motor propeller blades, the cutting blade tip end is orthogonal to the cylindrical cover  20  longitudinal central axis  24 , e.g.,  FIG. 3 . If the pitch of the motor propeller blades was seventy degrees in relation to the cylindrical cover  20  longitudinal central axis  24 , optimum cutting effectiveness from propeller propulsion would be attained with a cutting blade tip end is also disposed seventy degrees from the cylindrical cover  20  longitudinal central axis  24 , and so on. Cutting blades  60  will be manufactured to adapt to the variety of propeller blade pitches in the marketplace. It will be understood that the range of angle for propeller pitch and corresponding cutting blade tip end in relation to the cylindrical cover  20  longitudinal central axis  24  typically is between sixty (60°) degrees and ninety (90°) degrees. This angle for propeller pitch and corresponding cutting blade tip end in relation to the cylindrical cover  20  longitudinal central axis  24  would not be more than ninety (90°) degrees. This optimal cutting blade tip end angle relative to the motor propeller and cylindrical cover  20  longitudinal central axis  24  also ensures that the optimum cutting effectiveness is maintained when motor propeller  102  rotation is reversed. 
     An embodiment of the improved cutter assembly  10  for a motor propeller  102 ,  FIG. 12 , provides a cutting blade  60  fastener attachment assembly  80  to the exterior surface  26  of the cylindrical cover  20 . The cutting blade  60  fastener attachment assembly  80  includes a cutting blade  60  support base  63  and a top plate  82  fixedly attached to the exterior surface  26  of the cylindrical cover  20  by at least one threaded fastener  84 . 
     An alternative embodiment of the improved cutter assembly  10  for a motor propeller  102 ,  FIGS. 13-15 , provides a quick release cutting blade  60  attachment assembly  70  to the exterior surface  26  of the cylindrical cover  20 . The quick release cutting blade  60  attachment assembly  70  includes support posts  72  with post caps  74  extending from the exterior surface  26  of the cylindrical cover  20 . A cutting blade  60  support base  65  is positionally fitted onto support posts  72 , and secured onto the support posts  72  by sliding the support base  65  towards the cylindrical cover  20  forward end  30 . The support base  64  is then locked onto the JO support posts  72  by sliding a locking plate  76  having spring elements  78  sized to receive and secure the support post  72  caps  74 , towards the cylindrical cover  20  forward end  30  thereby securing the cutting blade  60  to the cylindrical cover  20 . The cutting blade  60  is quickly removed from the cylindrical cover  20  by depressing the spring elements  78 , sliding the locking plate  76  towards the aft end  32  of the cylindrical cover  20 , then similarly sliding the cutting blade  60  support base  65  towards the aft end  32  of the cylindrical cover  20 , and lifting the cutting blade  60  support base  65  off the support posts  72 . 
     An embodiment of the improved cutter assembly  10  for a motor propeller  102 ,  FIG. 12 , provides a gasket  34  sized to be received on the cylindrical motor housing  100  before the cover halves  12  are closed around the cylindrical motor housing  100 . The gasket  34  includes a notched aft end portion sized to clear the vertically disposed shaft  104  attached to a top side of the cylindrical motor housing  100  as the gasket is positioned onto the cylindrical motor housing  100 . Thus positioned, the gasket  34  serves to prevent any movement of the cutting blades from the initial angular positions described in  FIG. 9  with respect to the longitudinal central axis  24 , e.g.  FIG. 2 , during operation of the improved cutter assembly  10  for a motor propeller  102 . 
     An embodiment of an improved cutter assembly  110  for a motor propeller  102  that is directly attached to the cylindrical motor housing  100  includes four cutting blades  160 ,  FIG. 16 . Each cutting blade  160  provides a pair of cutting edges  163  positioned on either side of a cutting blade surface  164  having a concave portion and a cutting blade surface  162  having a convex portion. Each cutting blade  160  surface  164  and surface  162  taper to a cutting blade tip end. Each cutting blade  160  base end  161  is sized to be received by and adaptively fit into a cylindrical motor housing  100  mounting element  174  integral to the cylindrical motor housing  100  exterior surface,  FIGS. 16-18 . Each cutting blade  160  base end  161  is held in the cylindrical motor housing  100  mounting element  174  by a spring pin  178  having one end attached to the mounting element  174  and having another end engaged in a receiving notch  163  of the cutting blade  160  convex cutting blade surface near the cutting blade  160  base end  161 ,  FIG. 18 . The cutting blade  160  base end  161  bottom surface presents a wider width dimension than the cutting blade  160  base end  161  top surface corresponding to similar width dimensions of the cylindrical motor housing  100  mounting element  174 ,  FIG. 17 , to securely hold the cutting blade  160  base end  161  within the cylindrical motor housing  100  mounting element  174  when the spring pin  178  has engaged the receiving notch  163 ,  FIG. 18 . The cutting blade  160  is quickly and easily removed from the cylindrical motor housing  100  mounting element  174  by releasing the spring pin  178  from the receiving notch  163 , and sliding the cutting blade  160  base end  161  from the cylindrical motor housing  100  mounting element  174 . In this fashion, dull or broken cutting blades easily can be replaced, or the entire set of cutting blades removed for motor use outside the grassy cover environments. 
     The arrangement of the cutting blades  160  each fitted within cylindrical motor housing  100  mounting element  174  around the cylindrical motor housing  100  is similar to the embodiment of an improved cutter assembly  10 , as depicted in  FIGS. 9 and 10 , such that each cutting blade  160  is ninety degrees from adjacent cutting blades  160  with respect to the cylindrical motor housing longitudinal central axis  24 . In this manner, the orientation of each cutting blade  160  is forty-five degrees from an axis orthogonal to the cylindrical cover  20  longitudinal central axis  24 . Each cutting blade  160  surface  164  having a concave portion faces the cylindrical motor housing  100  forward end. Each cutting blade  160  surface  162  having a convex portion faces the aft end cylindrical motor housing  100  proximate to the motor propeller  102 ,  FIGS. 9 ,  10  and  16 - 18 . 
     Likewise, the same optimum cutting effectiveness from propeller propulsion that is attained when the angle of the cutting blade tip end is parallel to the pitch of the blades of the motor propeller  102 , as shown in  FIG. 10  for the embodiment of the improved cutter assembly  10 , applies for cutting blades  160  for the embodiment of an improved cutter assembly  110  affixed to the cylindrical motor housing  100 . Cutting blades  160  will be manufactured to adapt to the variety of propeller blade pitches in the marketplace. It will be understood that the range of angle for propeller pitch and corresponding cutting blade in relation to the cylindrical motor housing  100  longitudinal central axis  24  typically is between sixty (60°) degrees and ninety (90°) degrees. The angle would not be more than ninety (90°) degrees. This optimal cutting blade angle relative to the motor propeller and cylindrical motor housing  100  longitudinal central axis  24  also ensures that the optimum cutting effectiveness is maintained when motor propeller  102  rotation is reversed. 
     The cover halves  12  and resulting cylindrical cover  20  can be fabricated from aluminum, graphite or similar high impact carbon based materials. The cutting blades  60 ,  160  can be fabricated from high quality, extremely hardened steel with thin dual cutting edges  63 ,  163  carved by lasers. Alternatively, the cutting blades  60 ,  160  can be fabricated from ceramics, or graphite or similar high impact carbon based materials known to provide and hold nearly razor sharp cutting edges  63 ,  163 . Fastener assemblies  40 ,  50 ,  70 ,  80 , 174  or  178  can be fabricated from aluminum, stainless steel, graphite or similar high impact carbon based materials. 
     The gasket  34  can be fabricated from rubber, soft-density plastics, cork, high-strength carbon fibers, hard-pressed woods fibers, or similar high strength, gripping materials. The preferred embodiment of improved cutter assembly  10  includes a rubber gasket  34 . 
     It will be understood that the embodiments of improved cutter assembly  10  and  110  for a trolling motor propeller  102  would be adaptable to the full range of boat trolling motors available in the market either by retrofitting the improved cutter assembly  10  to an existing cylindrical motor housing  100 , or by original equipment manufacture of improved cutter assembly  110 . 
     Accordingly, while embodiments for an improved cutter assembly  10  and  110  for a trolling motor propeller  102  are disclosed whereby the cutter assembly has been described as having certain preferred features and embodiments, it will be understood that the cutter assembly is capable of still further variation and modification without departing from the spirit of the cutter assembly, and this application is intended to cover any and all variations, modifications and adaptations of the cutter assembly which fall within the spirit of the invention and the scope of the appended claims.