Downrigger fishing system and releasable connection
TECHNICAL FIELD 
     The invention relates to a downrigger fishing system and a releasable connection for attaching a fishing line to the downrigger line at a predetermined depth. Downriggers are typically used for deep fishing while trolling or when the water is flowing relative to a fishing line. 
     BACKGROUND ART 
     In deep water sport fishing a heavy weight is employed at the end of a downrigger cable and a connection device is provided to hold the fishing line to the downrigger at a desired deep level in the water. A release device is required to free the fishing line from the downrigger line when a strike occurs. In the prior art these devices have generally been mechanically complicated or magnetic. Some of the devices have been subject to corrosion, others either failed to release or release too easily. Where the devices hold the fishing line too securely, there is a tendency to break the line when a strike occurs and this requires the use of excessively heavy lines to avoid their breakage. 
     A search of the patent literature disclosed a number of devices for releasing the line when a strike occurs. For example, U.S. Pat. No. 4,012,863 to Lori shows a relatively complicated releasable device and also one that appears to be subject to be released too easily from the downrigger. 
     The following patents, found in the search, are of general interest: 
     U.S. Pat. No. 2,545,185  Winslow 
     U.S. Pat. No. 2,562,054  Mathieu 
     U.S. Pat. No. 2,687,592  Purcell 
     U.S. Pat. No. 2,830,400  Perry 
     U.S. Pat. No. 3,229,408  Kohfield 
     U.S. Pat. No. 3,614,700  Harrison 
     U.S. Pat. No. 3,628,274  Wojahn 
     U.S. Pat. No. 3,861,074  Wood 
     U.S. Pat. No. 3,925,920  Walker 
     U.S. Pat. No. 3,930,330  Black 
     U.S. Pat. No. 3,939,595  Lockett 
     U.S. Pat. No. 3,974,589  Henze et al. 
     U.S. Pat. No. 4,065,869  Berry 
     U.S. Pat. No. 4,212,127  Daniels. 
     DISCLOSURE OF THE INVENTION 
     The invention is a downrigger release system and an improved releasable connection between a downrigger line and a fishing line. 
     The invention includes a rudder plate having upper and lower end portions, the upper end being connectable to the lower end of an upper downrigger line, extending downwardly from a boat to the rudder plate, and a lower line having its upper end connected to the lower end of the rudder plate and having its lower end connected to a downrigger weight or kite. The rudder plate has a downwardly opening blind slot in a lower rear or trailing portion. A downwardly extending finger is positioned immediately rearwardly or trailingly of the slot, the finger having a generally straight forward or leading edge and having a trailing edge extending along and below the trailing edge of the rudder plate. 
     An eye member or trigger has a forward connector eye bounded at its front or leading edge by a bight portion, sized to fit loosely within the slot. The bight portion includes a rearwardly directed inner surface which makes substantially a point contact with the forward edge of the finger when the bight portion of the forward connector eye is within the slot and the finger is within the forward connector eye. 
     The eye member includes a second eye or opening in a rear or trailing portion of the eye for receiving the fishing line. The fishing is taut between the eye connector and the pole and the line is twisted at a location spaced from the hook, adjacent the eye member to prevent relative sliding movement of the fishing line through the rearward connector eye. 
     The rudder plate has a plurality of selectively usable connector holes spaced apart along the upper portion and along the lower portion so that the location of the downrigger line to the rudder plate can be changed relative to the rudder plate for changing the slope of the forward or leading edge of the finger. The upper and lower connector means are positioned so that the forward edge of the finger may be held substantially parallel between an imaginary line which extends between the upper and lower connector means, so that the forward edge of the finger leans rearwardly relative to an imaginary line extending between the upper and lower connector means, and so that the forward edge of the finger leans relatively forwardly to an imaginary line extending between the upper and lower connector means. These variations make the hook end of the line easier or harder to release from the finger which forms an inverted hook. 
     The substantial point contact between the inner surface of the bight portion of the forward eye and the forward edge of the finger is normally upwardly within the slot a great distance relative to the length of the point contact and the lengths of the slot and finger. This provides a low friction holding arrangement with great security against improper release, that is, release without a strike. Typically, when the fishing hook and lure are extending substantially directly toward the rear, as the result of relative movement between the downrigger and the water, there is a direct pull of the hook end of the line on the leading edge of the finger through the eye connector. Thus, temporary lateral movement or temporary inadvertent tilting in the plane of the rudder plate will not cause the eye connector to be released from the finger because the fishing line is normally taut. That is, no mechanical advantage is created to release the eye connector by such lateral movement or tilting. 
     The taut fishing line holds the eye connector in an upper position relative to the upper end of the downwardly opening slot along the finger. Thus, as the downrigger is moved by trolling or by the force of water, the fishing line is held securely to the rudder plate but when a strike occurs on the hook, the rudder is tilted so that the forward edge of the finger is slanted toward the downrigger line, and the low resistance of the substantial point contact, of the bight of the eye connector on the finger edge, allows the eye connector to slip off of the finger and free the line so that the fish on the hook can be played. The tilt caused by a strike is permanent until the fishing line is released. 
     Further advantages of the invention may be brought out in the following part of the specification wherein small details have been described for the competence of the disclosure, without intending to limit the scope of the invention which is set forth in the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the accompanying drawings which are for illustrative purposes: 
     FIG. 1 is an elevational view of a downrigger fishing system according to the invention; 
     FIG. 2 is an enlarged view of a rudder plate illustrating the connection to the fishing line; 
     FIG. 3 is a view of the rudder plate shown in FIG. 2, illustrating the release of the fishing line connection from the plate when a strike occurs; 
     FIG. 4 is an enlarged side view of a trigger or eye connector for engaging the fishing line with the rudder plate as indicated in FIGS. 2 and 3; 
     FIG. 5 is a plan view of the eye connector shown in FIG. 4; 
     FIG. 6 is an enlarged fragmentary view illustrating the normal engagement of the eye connector with a finger on the rudder plate and the movement toward the release when a strike occurs; 
     FIG. 7 is a partially cross sectional plan view illustrating a substantial point connection between the trigger and the finger on the rudder plate, taken along the lines 7--7 in FIG. 6; 
     FIG. 8 is a view illustrating the connection between the eye connector and the fishing line; 
     FIG. 9 is an elevational view of the rudder connected to upper and lower downrigger lines so that a forward surface on the finger extends rearwardly relative to an imaginary line between the connection points of the downrigger lines on the rudder plate; 
     FIG. 10 is an elevational view of a rudder plate connected to the upper and lower downrigger lines so that the forward surface on the finger extends forwardly relative to an imaginary line between the connection points of the downrigger lines on the rudder plate; 
     FIG. 11 is an end view of another embodiment of a trigger or eye connector; and 
     FIG. 12 is a plan view of the eye connector shown in FIG. 11. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Referring again to the drawings, there is shown in FIG. 1, the aft end of a boat 10 having an upper end 12 of a downrigger upper line 14 secured to a winch 16. The lower end 20 of the upper line 14 is secured to a rudder plate 24 at one of three spaced upper end connections in the form of holes 28, 30, and 32. As best seen in FIG. 2, the specific connection is to a central hole 30. 
     A lower downrigger line 36 has its upper end 38 connected to a central hole 40 of three spaced lower connection holes 42, 40, and 44. Connected to the lower end 46 of the lower downrigger line is a weight 48 which holds the rudder plate 24 at a desired depth in the water. As shown in FIG. 1, relative movement between the downrigger lines and the water is holding the downrigger system rearwardly with respect to the boat. 
     Upwardly of the lower end of the rudder plate and the lower spaced connections is a downwardly extending member or finger, generally designated as 50. The finger 50 has a rearward or trailing edge 52 extending along the rearward edge of the rudder plate 24, has a bottom or lower end 54, and has a forward or leading edge 56. Forwardly of the leading edge 56 is a blind slot 60, having its closed end 62 extending above the lower connection means 40, 42, and 44. 
     As shown in FIG. 1, a fishing rod 66 is secured to the rear of the boat and a fishing line, generally designated as 68 has an upper end 70 extending from the pole 66, having a lower end 72 engaged with an eye connector 74, and having a lure and hook portion 76 generally trailing from the eye connector 74, engaged with the finger 50. The lure is indicated as 80 and the hook 82. Where the fishing is by trolling or where the water is moving relative to the boat, the lure 80 and hook 82 typically trail as shown in FIG. 1. 
     The eye connector or trigger 74 is shown in detail in FIGS. 2, 4, 5, and 8. A forward eye or slot 86 has convex curves 90 and 92 at its rearward and forward ends, FIG. 4, and a rearward or trailing eye or opening 96 also has rearward and forward convex curves around the opening. 
     The fishing line is secured, FIG. 8, to the eye connector 74 in the eye 96, against relative sliding of the line and the connector, by means of a series of twists 78. 
     As shown in FIGS. 2, 6 and 7, a forward bight portion 104, formed at the front of the eye opening 86, fits loosely within the slot 60 and its inner surface makes substantially a point contact 106 with the forward edge 56 of the finger. 
     Selective connections of the downrigger lines to the holes 28, 30, 32 and 40, 42, and 44 vary the ease of disengagement of the eye connector 74 from the finger 50. In normal operation, depending upon the speed of relative movement between the lines and the water, the upper downrigger line 14 could be secured to the connection hole 30 and the lower downrigger line 36 could be secured to the connection opening 40, as shown in FIGS. 1-3. In this situation the forward edge 56 of the finger is parallel to an imaginary line between the connection openings 30 and 40 and there is no relative tilting between imaginary line and the forward finger surface. In FIG. 3, the rudder plate 24 and the forward finger surface 56 are both tilted, as would occur when there is a strike. The tilting is caused by increased pull on the line portion 76, causing the trigger or eye connector 74 to pull on the forward surface 56 of the finger so that the eye 86 slides down the finger and off thereof. 
     In FIG. 9 the upper downrigger line 14 is connected to the hole 28 and the lower downrigger line 36 is connected to the hole 44. In this arrangement a greater pull by the fish on the line 76 and on the trigger 74, than in the arrangement in FIG. 3, is required to tilt the rudder plate and finger 50 sufficiently to cause the eye 86 to slip off of the finger. 
     In FIG. 10 the upper downrigger line is secured to the hole 32 and the lower downrigger line is secured to the hole 42 and in this selective arrangement less pull is required by the fish on the trigger 74 to tilt the finger and rudder plate so that the eye 86 is disengaged from the finger. In FIG. 9 the selective connection is such that the forward edge of the finger leans rearwardly relative to an imaginary line between the connecting means 28 and 44 and in FIG. 10 the selective connection is such so that the forward edge of the finger leans forwardly relative to an imaginary line between the connection means 32 and the connection means 42. 
     To set up the downrigger system, according to the invention, as shown in FIG. 1, the weight 48 is lowered a short distance over the side of the boat. The trigger 74 is held in one hand and 15 to 40 feet of fishing line are drawn through the eye 96. The lure 80 and hook 82 are then attached to the distal end of the line portion 76. The trigger is rotated about six times relative to the fishing line to form the holding twists 78. 
     The trigger is then attached to the rudder, slipping the eye 86 onto the finger 50. The downrigger line or cable 14, 36 is lowered to the desired depth, maintaining tension on the fishing line to hold the trigger on the finger 50. As indicated when a relatively large fish bites or strikes the hook, the rudder will be tilted and the trigger will slip off the finger. The twists 78 unwind and the trigger is free to slide on the fishing line. 
     To otherwise release the trigger, the downrigger cable is cranked upwardly until the rod 66 springs upwardly. When this occurs, the trigger and lure have been released from the rudder. 
     Irrespective of the selective arrangements of the connector means 28, 30, and 32, and 40, 42, and 44 with the upper and lower downrigger lines, respectively, the positioning of the bight 104 relative to the forward edge 56 of the finger is as shown in FIGS. 6 and 7. Because the bight portion 104 loosely fits within the slot and makes substantially a point contact with the forward edge of the finger, there is always a direct pull, as generally indicated in FIG. 1 and specifically indicated in FIG. 7, of the fishing line 76 and the eye connector on the finger so that temporary relative movements between the finger and the bight 104 will not cause the trigger to slip off of the finger. That is, lateral movements of the rudder plate relative to the eye connector 74 or temporary inadvertent tilting in the plane of the rudder plate will not cause the eye connector to be released from the finger. 
     The tautness of the fishing line holds the eye connector upwardly in the slot a great distance relative to the thickness of the point connection at 106 and the lengths of the slot and finger. The arrow 110 in FIG. 6 indicates the amount of movement possible along the surface of the finger that can occur without causing the eye connector to be pulled off of the finger. 
     Thus, temporary movements, not caused by a strike, relative to the eye connector and the rudder plate do not cause a moment arm or other mechanical advantage to be created so as to allow easy release of the eye connector. For example, it may be understood from a study of FIG. 7 that twisting movements of the finger at 106 would not be significant so as to change the relative positions of the eye connector and the finger. Similarly, the temporary tilting of the rudder plate would not affect the point contact at 106 so as to cause the eye connector to be released from the finger. The arrangement is such that only a sustained pull resulting from a strike would sufficiently tilt the finger to cause the eye connector to be disengaged therefrom. This action is indicated in FIG. 3. As shown in FIG. 6 in broken lines, the positions of the finger in the tilted position and of the bight 104 indicated that a greater amount of tilting is required to cause the eye connector and finger to become disengaged. 
     However, it should be noted that the low friction substantial point connection permits an ease of disengagement by a strike. 
     In FIGS. 11 and 12 another embodiment of a trigger or eye connector, generally designated as 112, is shown. It is formed of wire and has a forward eye 114 for sliding on the finger 50 and has a rearward eye 116 for the fishing line. The wire is crimped together at 120 with a flattened plate. The forward eye 114 has inner convex surfaces at 122 to make substantially a point contact on the forward surface 56 of the finger. 
     The invention and its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction, and arrangements of the parts of the invention without departing from the spirit and scope thereof or sacrificing its material advantages, the arrangements hereinbefore described being merely by way of example. I do not wish to be restricted to the specific forms shown or uses mentioned except as defined in the accompanying claims.