GB2430734A

GB2430734A - Bite indicator

Info

Publication number: GB2430734A
Application number: GB0519940A
Authority: GB
Inventors: John Douglas Anderson; Stephen Anthony Lawrenc Foulds; Derek Romang
Original assignee: Delkim Products Ltd
Current assignee: Delkim Products Ltd
Priority date: 2005-10-03
Filing date: 2005-10-03
Publication date: 2007-04-04
Anticipated expiration: 2025-10-03
Also published as: GB2430734B; GB0519940D0

Abstract

A bite indicator comprises a support point 30 over which a fishing line is guided during use and a position sensor 40 located at a fixed distance from said support point for determining the position of the fishing line transverse to the direction of the fishing line, so as to indicate the attitude of the fishing line relative to the horizontal at the support point. The position sensor 40 is preferably a non contact optical sensor such as CCD or a simpler arrangement using a triangular window, LED, and photodetector. The indicator is also able to alert the owner to theft of the device in the condition of the line being absent.

Description

BITE INDICATOR

Field of the invention

The present invention relates to a bite indicator.

Background of the invention

In angling, a technique known as legering presents a bait on the bed of a lake or river, held in place by a leger weight. In order to indicate a bite from a fish using this technique, it is common to place a small weight suspended on the fishing line between the line guides of the fishing rod which is placed on a rod support. Changes in the tension of the fishing line are then indicated by up and down movement of this weight. Typically such weights, commonly termed "bobbins", may be free hanging or mounted on an arm that swings about a fixed horizontal axis or mounted to slide up and down a fixed pole etc. In all cases, the weight is connected to the line by a form of clip that releases automatically when the fishing rod carrying the line is pulled away from it.

The movement of the weight up and down indicates if the line tension is changing, as would be caused by a fish taking the bait on the line and then swimming towards or away from the fishing rod.

Object of the invention The problem in relying on such a visual indication is that it is not precise and it also calls for the angler not to turn his attention away from the weight and the aim of the present invention is to mitigate these disadvantages.

Summary of the invention

In accordance with the present invention, there is provided a bite indicator comprising means defining a support point over which a fishing line is guided during use and a position sensor for determining the position of the fishing line along a line which extends transversely to the length of the fishing line and lies at a fixed distance from said support point, so as to indicate the attitude of the fishing line relative to the horizontal at the support point.

The invention is predicated on the realisation that though it is difficult to provide a sensor to determine up and down movement of a line tensioning weight, the same information can be derived from monitoring the attitude of the line as it passes through one of the two adjacent support points between which it is tensioned. However, whereas there is no convenient fixed reference point relative to which one can measure the position of the line clip of the line tensioner, one of the two points between which the line is tensioned provides a suitable measurement reference.

It is preferred for the position sensor to be a non- contact optical position sensor to avoid placing any additional drag on the line and allow the line to be lifted off the sensor without any risk of it becoming entangled.

The optical position sensor may be an analogue sensor responsive to the blocking by the line of a tapering transmission window. Alternatively, the optical position sensor may be a digital sensor having a plurality of picture elements and operative to determine the position of the fishing line from an image of the fishing line formed on the sensor. 3 -

The line attitude sensor of the invention may, as with other bite indicators comprise means for producing an audible or visible signal in response to a change in the attitude of the fishing line at the support point and it may also be used to indicate if the angle made by the fishing line at the support point is increasing or decreasing.

In the preferred embodiment of the invention, the support point is formed by a line movement sensor that vibrates when the line moves relative to the support point.

In this way a single unit can act both as a line movement sensor and a line tension sensor.

By combining the line tension sensor with a line movement sensor, one can overcome the problem of short battery life that would arise in a bite indicator relying at all times on optical line position sensing because power to the line position sensor need only be switched on after line movement has been detected by the line movement sensor.

Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which Figure 1 is a schematic representation of a fishing rod resting on a bite indicator of the invention using a weight on a swinging arm to tension the fishing line, and Figure 2 is a schematic representation of the geometry of an analogue optical line position sensor.

Detailed description of the preferred embodiment

In Figure 1, a fishing rod 10 having a fishing line 12 passing through rings 14 is shown resting on a bite indicator 16, itself mounted on a rod rest (not shown) . The bite indicator 16 comprises all the components of a conventional bite indicator and its internal design and method of operation need not therefore be described in detail in the present context. It suffices to know that when the fishing rod 10 is supported in a V-shaped recess at the top of the bite indicator 16, its line passes over a sensor which is not shown but lies at the illustrated point of inflection of the fishing line 12. As the line moves over the sensor, the latter vibrates and the vibrations are used to produce an audible alarm and to flash an LED 18 on the front of the bite indicator 16.

A line tensioner, generally designated 20 is used to maintain the line taut between the two rings 14. The illustrated line tensioner comprises a weight 22 slidable along an arm 24 that is pivotably mounted on a fixed bracket 26 gripped between the bite indicator 16 and the rod rest.

The free end of the arm 24 carries a clear plastics body 28 which is in turn connected by a line clip 30 to the fishing line 12. The plastics body is used at night to receive a glowing capsule or an LED so that it can be seen more easily. Instead of a weight 22, line tensioners are also available that use a spring biased arm.

Everything so far described is entirely conventional.

Aside from maintaining the line 12 taut, the arm 24 moves up and down when the line tension changes and this is in itself a valuable indication that is used by anglers in addition to the signal emitted by the bite indicator 16 when it detects line movement.

However, visual monitoring of the position of the body 28 is not particularly accurate especially since the angler may not be watching it at all times. To provide a signal equivalent to the up and down movement of the weight 22, the illustrated embodiment of the invention comprises an optical line position sensor 40 mounted on the bite indicator 16 near the line movement sensor to monitor the angle of the fishing line as it passes over a fixed point defined by the line movement sensor. As can readily be seen from Figure 1, if the line tension increases, the fishing line will move towards the rod 10 and become more horizontal and conversely if a fish reduces line tension by swimming towards the fishing rod, the weight 22 will drop and with it the line 12 will move towards a more vertical attitude.

The angle made by the line at the bite indicator can be determined using a CCD (charged coupled device) camera or the like digital image sensor. However, it is simpler and currently less expensive to adopt an analogue approach using the principle that will now be described with reference to Figure 2.

An LED and an optical detector (not shown), for example phototransistor, photodiode, light dependent resistor or photovoltaic cell, are used to measure the intensity of light transmitted through a triangular window 42, or windows, partially obscured by the fishing line. Three different possible positions of the fishing line are represented by the lines 12a, 12b and 12c in Figure 2. It can be seen that in the position 12a very little of the window is obstructed but as the line tension becomes more slack and the line moves to the positions 12b and 12c the proportion of the window 42 obstructed by the line becomes progressively greater. The output of the phototransistor is therefore indicative of the position of the fishing line.

Unlike a digital optical sensor, the output of the phototransistor needs to be calibrated to provide an absolute measurement of the position of the line but in practice such a measurement is not needed as it is only changes in the attitude of the line that are important not the exact angle of the line at any one instant. The bite indicator may therefore include circuitry to sense changes in the position of the line and provide an appropriate visual or audible indication of the change in line tension.

It is desirable for the signal to indicate not only the fact that a change has occurred but also the direction of the change.

As a change in the attitude of the line will invariably be accompanied by some degree of line movement, it is desirable to use the line movement indicator to switch on the power to the circuitry of the line position sensor so as to reduce the load on the power supply of the indicator.

It is important for the illumination falling on the sensor to be even and this may be achieved by collimating the light falling on the sensor by placing an optical lens at the focal distance in front of the LED.

The LED's and sensors may operate in the infrared range and filters may be used to reduce interference from ambient daylight.

The bite indicator of the invention can also serve as the sensor of a burglar alarm system, in that it can detect the absence of a fishing line within the sensing window. If there is no line blocking the light falling on the sensor the assumption is that the rod has been picked up. If the burglar alarm is set, anyone attempting to steal the fishing rod would of necessity remove the line from the sensing window causing an alarm to be sounded.

Various further modifications may be made to the described preferred embodiment of the invention, without departing from the scope of the invention as set forth in the appended claims. For example, the position of the pivot point relative to the triangle, and the geometry of the triangle may differ from that that shown in Fig 2. Thus, one can contemplate a window having a right angle triangle with a maximum obstruction for a horizontal line and minimum at higher angles.

Claims

1. A bite indicator comprising means defining a support point over which a fishing line is guided during use and a position sensor for determining the position of the fishing line along a line which extends transversely to the length of the fishing line and lies at a fixed distance from said support point, so as to indicate the attitude of the fishing line relative to the horizontal at the support point.

2. A bite indicator as claimed in claim 1, in which the position sensor is a non-contact optical position sensor.

3. A bite indicator as claimed in claim 2, wherein the optical position sensor is an analogue sensor responsive to the blocking by the line of a tapering transmission window.

4. A bite indicator as claimed in claim 2, wherein the optical position sensor is a digital sensor having a plurality of picture elements and operative to determine the position of the fishing line from an image of the fishing line formed on the sensor.

5. A bite indicator as claimed in any preceding claim, further comprising means for producing an audible or visible signal in response to a change in the attitude of the fishing line at the support point.

6. A bite indicator as claimed in claim 5, wherein the means for producing an audible or visible signal serve to produce different signals to indicate if the angle made by the fishing line at the support point relative to the horizontal is increasing or decreasing.

7. A bite indicator as claimed in any preceding claim, wherein the support point is formed by a line movement sensor that vibrates when the line moves relative to the support point.

8. A bite indicator as claimed in claim 7, wherein power to the line position sensor is switched only after line movement has been detected by the line movement sensor.

9. A bite indicator as claimed in any preceding claim connected to a burglar alarm system and operative to produce an alarm signal when no line is detected by the line position sensor.

10. A bite indicator substantially as herein described with reference to and as illustrated in the accompanying drawings.