GB2446206A - Fishing scope - Google Patents

Abstract

The Fishing Scope is a gun-sight for mounting on a gun, crossbow or other missile projection device, to enable accurate shooting of underwater targets from above the water surface by compensating for the water surface-to-air refraction. The scope viewer can be focused on the apparent image of the underwater target, whilst the gun projectile is aimed directly at the real underwater target. The apparatus comprises a pivot between the gun and the gun-sight viewer, and a servo mechanism that is able to adjust the angle between the gun and the viewer. The servo is driven by a computer in response to readings from measurement devices for a scope or gun tilt, height of the scope above the water, and distance from the scope to the target. The height may be measured by a differential pressure gauge connected to the scope at one end and placed in a float on the water at the other end. The distance to target may be measured from the focus setting of the telescopic lens of the scope viewer or by some other distance measuring device such as laser distance measurement. The viewer may be electronic.

Description

Description -Fishing Scope

Thzr document Lc an application by the inventor Trevor Maddison (Managing Director and owner of Revcad Software -Sole Trader) for a Patent for a design that has been named the Ftshing Scope' (Date: 29 January 2007).

Technical Field

This document is an application by the inventor Trevor Maddison (Managing Director and owner of Revcad Software) for a Patent with priority claims and a description of a design that has been named the Fishing Scope'.

The Fishing Scope (hereafter also referred to as the scope') is a design invention for the outdoor pursuits and survival, or hunting and fishing application. The design is a special telescopic gun-sight designed to be fitted to a gun for surface to underwater target shooting (or fishing) using a gun, or some other means of firing a projectile (hereafter referred to as the gun'). The Fishing Scope' is a type of gun-sight with special modifications to overcome the problem of water surface-to-air light refraction when shooting underwater targets. The design implements an automatic relative angular alignment adjustment between the scope viewer and the gun in response to its integrated instnimentation such that the scope viewer can be pointed directly at the refracted image of the underwater target whilst the gun is pointed directly at the physical underwater target.

Background Art

There are no other known design solutions in the hunting and fishing application to the problem of automated adjustment to compensate for the effects of light refraction. The design solution claimed makes use of the following technologies: Gun, Bow & Crossbow -The proposed design is an accessory to gun, bow, crossbow and other missile projection technology. As an accessory to these devices it does not include any of the technology or prior art of hunting and shooting devices.

Tilt Angle Measurement -Tilt sensors exist to measure the angle of tilt to the horizontal.

Tilt sensors are invariably gravity based and have many applications, such as autopilot control of aircraft. These instruments are generic solutions for measuring tilt angles.

Telecoplc Viewer (or Gun-Sight) -Telescopes or telescopic viewers use lens technology and have been used in various application for many years, dating back as far a Galileo and before. In more modem times they have been widely used in hunting and military applications. These form part of the basic prior art of the claimed design solution. In the case of the proposed deSign the focal lengths of the viewers are relatively short and in this respect are more akin to technology used in cameras than in hunting applications. The viewer is a constitutional part of the proposed design. K is also possible to implement the proposed design using electronic viewer alternatives as are commonly used on modern digital cameras.

I

Distance Moasurement -Telescopic sights have also been used in surveyors instruments and other devices for measuring a distance to a target. This forms part of the prior art of the design. More modern alternatives for measuring distance are also available. This includes the laser technology for distance measurement, now used in many applications (e.g. industrial reverse engineering, robotics, golf distance reading). The proposed design is not specifically applied to any one distance measuring instrument, but is more general in that it simply covers the use of a distance-to-target measuring instrument. The best mode of invention describes the use of focal distance as the means of measurement but other methods can be equivalently applied to the design. In the case of focal distance measurement -technology exists to implement automatic focus adjustment -as used in modem cameras. Auto-focus would constitute an enhancement of the proposed design and could therefore form part of the prior art.

Height Measuiement -The proposed design includes a device to measure the distance to the water surface. The best mode of invention proposes the use of a height differential gauge.

This may consist of a tube filled with fluid and a pressure gauge fitted in the lower end. The height between the two ends of the tube is then determined from the fluid pressure. The proposed design is not restricted to this type of device for height measurement. The distance to the water surface can alternatively be measured using a laser measurement technology or some other instrument (note: either the vertical or slant distance to the water surface are acceptable readings for the device to work).

The patent claim is based on the combination of these devices and instruments to solve the design problem, rather than as an advancement of any of these technologies. The design therefore proposes the use of these technologies although the actual patent claim is for their combination to solve the particular design problem.

Technical Problem The fishing scope design addresses an ancient problem of shooting and hitting an underwater target (e.g. fishing) using a harpoon, gun or spear gun to spear a fish (or target) by shooting a projectile from above the water surface. The difficulty in the practice arises from the effects of water surface-to-air light refraction which bends the light as it passes through the water surface, thus displacing the visual image of a target from its true position. Hunters have attempted to overcome the problem by simply estimating the refraction, or in the case of spear fishermen by the method of dipping the spear to allow them to see the angle of refraction and use it to help them determine the required projectile direction of the spear to hit the target.

When the target is viewed at an angle to the water surface (other than the perpendicular) light refraction occurs as the image of the target passes through the water surface and this makes the target appear to be in a different location to its actual location from the point of view of an observer stationed above the water surface, in other words the target has an apparent location to the observer which differs from the real location. If a projectile is launched at the apparent image, as it would be using a conventional gun-sight, then the projectile will miss the target.

The design proposed here solves this problem by using a special gun-sight with various sensors and adjustment mechanisms that allow the observer to aim at the apparent target with a gun-sight viewer but automatically make the necessasy compensations to shoot at the real target rather than the apparent one.

Technical Solution The Fishing Scope' is a type of gun-sight that differs from a normal gun-sight in that the viewer is not rigidly aligned with the gun barrel or projectile direction but is mounted on a pivot and has an angular displacement servo mechanism or other adjustment device that is able to adjust the relative angle between the gun-sight viewer and the gun barrel (i.e. the projectile direction). The fishing scope is therefore able to automatically adjust to a relative vertical angle of alignment with the gun barrel to allow for the effects of surface refraction of light as the target image passes through the water surface. The adjustment is made automatically via the servo, or other adjustment mechanism, in response to the readings of various sensors attached to, or integrated with, the gun-sight (see details for the description of sensors).

The sensor readings are processed through a computer, or dedicated electronic chip, to determine the displacement (or position) of the servo required to achieve a calculated relative vertical angle between the projectile target direction and the sight direction. This means that by looking through the gun-sight and aligning it with an underwater target the gun-sight viewer will automatically adjust itself to a relative angle to the projectile so that the gun is pointing exactly at the target's real position whereas the gun-sight viewer is pointed only at the virtual' (or apparent) position. The gun-sight can therefore be used to shoot fish or other underwater targets from above the water surfce by accounting for surface light refraction..

Advantageous Effects The design enables surface to underwater fishing or target shooting by removing the problem of estimating the effects of water surface-to-air light of refraction. The design is applicable to rivers, lakes and sea fishing. It can be mounted on a gun, crossbow, bow or any other means of aiming and firing a projectile.

Description of Drawings

I. The Components (Fig.1) -The components drawing shows all the main components of the design including instruments.

a. Viewer-Used to aim the scope at the target by aligning the crosshairs with the target. Contains a tilt sensor to read the tilt angle of the viewer to the horizontal. Tilt angle data is fed to the computer (or chip) as one parameter for the servo mechanism response. The viewer also has a focus mechanism with a sensor to read the current focal distance of the viewer. The user focuses the viewer on the target (or auto focus) then a sensor reads the focal distance and feeds it to the computer. The focal distance is one of the parameters used to determine the servo mechanism response in order to achieve the required delta' angle.

b. Gun -Typical gun, crossbow or other aimer device for shooting a projectile. The proposed design does not include the gun itself but just the carriage which is mounted on the gun.

c. Sen,v -The servo mechanism is driven by the computer and is used to pivot the viewer to a relative angle to the gun such that the viewer points at the apparent image of the underwater target while the gun points directly at the target.

d. Differential Pmssure Gauge -Sensor device (usually a tube filled with fluid) to measure the height from one end of the tube to the other. The lower end has a float that floats on the water and may simply contain a pressure sensor to allow it to determine the height to the other end of the instrument.

The higher end is attached to the height datum point on the gun. An electrical signal is passed from the pressure sensor through a wire in the tube to the gun computer. The reading is used to determine the servo movement and therefore the relative delta' angle of the viewer to the gun.

2. Dimensions (Fig.2) -The dimensions drawing shows the important dimension of the design that are measured by the sensors and contribute to the calculation of the delta' angle (the angle between the viewer and the projectile) to achieve the real target alignment a. H = Height from the water line to a datum point on the fishing scope b. lift = The angle of the viewer to the horizontal.

c. dl+d2 = Focal distance of the lens when focused on the underwater target.

d. Delta = The Delta' angle between the alignment of the viewer and the gun, fixed by the servo mechanism.

Note: The line extending from the gun shows the path of the projectile to the target The lines extending from the viewer show the path of the light from the target, refracted through the water surface and into the viewer. The Delta angle has been set by the onboard computer or chip, based on the instrument readings, to make the two lines converge in the fishing scope at the same time.

Best Mode of Invention Main Components The main components of the design are a telescopic or electronic viewer mounted on horizontal hinged connection (or pivot) to the carriage'. The carriage is designed to be mounted rigidly on the gun and aligned with the projectile direction, the carnage should contain the electronics and the power pack to drive the electronics. A linear servo mechanism should be located between the viewer and the carnage so that any adjustment of the servo position setting will change the relative angle of orientation between the viewer and the carriage. The instruments outlined below should be mounted on either the viewer or the carriage (Note: the mathematical model used to determine the required adjustments must take account of the specific configuration) See Fig I. Instrumentation Parameters The gun-sight requires several physical/geometrical parameters (angles and distances) to be read by the on-board instrumentation for the design to work. These are: 1. The tilt angle of the viewer.

2. The height of the scope above the water surface.

3. The linear distance from the viewer to the underwater target.

We will discuss each of the readings and the proposed methods and sensors for reading them in turn, and the possible variations and considerations required for the product to operate correctly.

Tilt Angle of the Fishing Scope Aewer (Tilt) The tilt angle of the viewer can be read by a standard gravity based device for measuring tilt.

Generally this type of device would work by gravity and use an eccentric weight mounted on a spindle with very free rotation. The rotation angle is then read using an angular measuring device attached to the spindle. Other gravity based tilt measuring devices may be used. The tilt device should be integral to the fishing scope such that it is rigidly mounted on the viewer side of the pivot between the viewer and the gun. ilils allows the viewer tilt angle' in the vertical plane to be read by the tilt instrument.

Height of the Fishing Scope Above the Water Surface (h) The vertical height of the scope above the water surface is read using a tubular instniment filled with fluid. On one end of the tube is a float and in the float is a pressure sensor. To use the gun the float must be placed in the water and allowed to float on the surface of the water.

The pressure sensor in the float reads the pressure of the fluid at the water surface, which is then used to determine the vertical height position of the other end of the tube. The free end of the tube should be attached to the fishing scope via an electrical connection. The pressure reading is passed through a wire in the tube or tube wall from the pressure sensor in the float to an electrical socket on the fishing scope. The reading this instrument gives is therefore the height of a datum point on the scope above the surface of the water.

In all cases whether fishing from a river bank or sea shore, or from a boat, it is essential to put the float in the water before attempting to use the device. Where there are waves as in the sea, or where the gun is moving up and down through the boat rocking it may be a desirable option for the device to make continual readings and for the device to calculate the average height of the gun above the water (i.e. some form of damping). It is then necessary for the fisherman to shoot in mid swell', when the waves or the boat rocking is halfway through the cycle. This is part of the new skill in using the device in these conditions. Where the water is not swelling and the gun is steady this mode would not be essential.

The Linear Distance from the Fishing Scope to the Underwater (d) This is the distance that light travels from the underwater target to the scope viewer focal point. We propose to read this using the focal distance adjustment setting of the scope viewer in a similar way to the focus distance reading of a camera or surveyors instrument. The rotation of the focus mechanism should be calibrated to the focal distance, therefore allowing the rotation of the focus mechanism to be converted to a focal distance. If the target is brought into focus (either manually or by auto focus) then the distance from the gun sight to the target can be read by the instrument.

Alternatively the distance from the viewer to the target could be read by using a laser distance measuring device. Tests are required to make sure that readings can be made through the water surface and considerations should be given to the possibility of the laser disturbing the target (in the case of fish or similar) for this method to be a feasible alternative.

Servo Response to MJust the Viewer to Projectile Relative Angle The above readings provide all the information required to calculate the necessary delta angle between the projectile and the scope viewer in order to direct the gun projectile directly at the underwater target when the viewer is focussed on the target. The nearer to the perpendicular to the water surface the gun is held the lower will be the relative angle. Similarly the lower the angle of incidence of the viewer to the water surfce (i.e. the higher the angle from the vertical position) the higher the projectile adjustment angle is required.

Other Geometrical Considerations Note that the calculation of the relative angle of projectile to viewer must take account of some constant parameters that relate to the general geometry of the fishing scope. Various distance measurements must be taken into account in the mathematical model used. These are: I. The location of the datum point of the height reading on the scope relative to the delta angle pivot location.

2. The location of the focal point of the viewer relative to the delta angle pivot point.

3. The offset of the gun relative to the delta angle pivot point.

The relative position of each of these points on the scope design must be taken into account in the calculation of the relative angle. Mathematical models andlor computer programs to simulate the scope operation must take account of these parameters (see later).

Other Design Considerations The following issues may also require consideration in implementing the design through these items do not form part of the patent claim: 1. The design requires some means of attaching a fishing line to the projectile and dispensing the line with low resistance when the projectile is fired. Means of reeling in the line may also be required. The inclusion of a modified fishing reel is a possibility. This is not part of the design patent but is a requirement for a flmctional fishing design in order to retrieve both the projectile and the catch.

2. The projectile may be a crossbow bolt or an arrow. In these case a barb on the projectile may be required to retain the speared fish. This is also not part of the design patent.

3. A switch of some kind may be required to start and/or stop the automatic adjustment mechanism from operating in order to prevent the scope fim adjusting when simply being carried or moved. Ideally the user should be able to hold down a conveniently mounted, spring loaded button, or to throw a switch to initiate the delta angle adjustment once he has focused the viewer on an underwater target.

Mathematical Model for Delta Angie Adjustment The following mathematical model and computer algorithm outlines the calculation of delta angle calculation and setting required to adjust the aim of the gun to compensate for the water surface to air refraction: Assumptions: I. The tilt instrument measures the angle of the viewer (not the gun).

2. The height datum is located on the viewer side of the pivot.

3. Viewer coordinales assume the pivot to be the origin, the viewer direction to be the H axis and the vertically up perpendicular to the viewer direction to be the V axis.

4. Gun coordinates assume the pivot to be the origin, the projectile direction to be the H axis and the vertically up perpendicular to the projectile direction to be the V axis.

Variable/Instrument Inputs: t = Tilt angle of the viewer h = Height of height datum on the viewer to the water surface d = Distance from viewer focal point to underwater target Geometrical Constants: p2fl1 -Horizontal distance from the pivot to the focal point (in viewer coords).

p2fV -Vertical distance from the pivot to the focal point (in viewer coords).

p2hH -Horizontal distance from the pivot to the height datum point (in viewer coords).

p2hV -Vertical distance from the pivot to the height datum point (in viewer coords).

p2gV -Offset distance from the projectile line to the delta pivot (in gun coordinates).

alpha: (PiJ2t)*f; hph: p2hH*sin(t) + p2hV*cos(t); hp: h -hph; hpf: -p2f}Isin(t) + p2fV*cos(t); hf:'hp+hpf; if AppEQ(sin(t),O) then Exit; dl: hUsin(t); d2d-dl; p2tX: p2f}lcos(t) + p2fV*sin(t) + hfltan(t) + d2*sin(alpha); p2tY: hp + d2*cos(alpha); if not SinCosRoot(p2tX,-p2tY,p2gV,o,aangfel,aangle2) then Exit; if abs(aanglel -Pi/4) <(aangle2-Pi/4) then aangle: aangle 14 else aangle:= aangle2-t; delta:= aangle-t; Notes: The SinCosRoot function is a solution to the equation: a*sin(x)+b*cos(x) + c =0. The AppEQ function tests if the value is approximately zero within tolerance. This calculation assumes a configuration of the device where the tilt angle and the height datum exist on the viewer side of the pivot. Other configurations with one or both these sensors operating on the gun side of the pivot are possible but the above model must be modified to suit. If a linear servo mechanism is used to adjust the delta angle then the angle must be converted to a linear displacement according to the geometrical location of the servo mechanism end pivots.

Industhal Application This design solves an ancient problem faced by surface to underwater spear fishermen by allowing the hunter to take account of the surface refraction of light, which has in the past made surface to underwater fishing a difficult and highly skilled practice. The application of the fishing scope makes surface to underwater fishing almost as easy as normal target shooting using a gun or crossbow. The following procedure outlines the use of the invention: I. The fishing scope is mounted on a gun, crossbow or other means of aiming and launching a projectile.

2. The differential pressure gauge is attached to the fishing scope and the float on the end of the tube is placed in the water. This is an instrument that allows the fishing scope to measure its vertical height from the water surface. The float ensures that the water surface is the datum height of the measurement.

3. The gun is aimed at the underwater target using the fishing scope viewer and is therefore pointed at the water surface with some angle of incidence (i.e. the angle that the view direction strikes the water surface).

4. The target is then brought into focus by either manual or automatic adjustment of the focus screw mechanism on the viewer. A sensor on the viewer focus adjustment mechanism now allows the fishing scope to measure the linear distance to the target using the focal length setting of the fishing scope viewer. Alternatively in the case of laser devices the laser is simply aimed at the target and a distance reading can be automatically read by the scope sensor using laser distance reading technology.

5. A tilt sensor instrument is installed integrally with the scope to provide an angle of tilt' measurement reading as a parameter for electronic input. This parameter is the tilt angle of the gun to the horizontal.

6. The fishing scope responds to the various input parameters (i.e. tilt of scope, height to water, distance to target, geometry of gun and scope -see later) and automatically adjusts the viewer alignment, via the servo mechanism, to the necessary calculated delta' angle (the angle between the alignment of the viewer and the alignment of the gun). This means the viewer will move relative to the gun so it no longer points at the target. The user must now respond by raising or lowering the aim of the gun to realign the viewer to the target and therefore repeat the procedure from step 2. As the user makes these adjustments the aim of the gun will settle down so no more automatic adjustments are made by the fishing scope. The viewer is now aimed at the apparent position of the target and the gun is aimed directly at the real target.

7. The user can now go ahead and shoot the target.

Other things to note I. The fishing scope adjustment will be continuous. It is therefore necessary for the user to home in on the target, adjusting the gun aim until the automatic adjustments are corroborated with the manual adjustments (of tilt and focal length) and the aim settles down (i.e. ceases adjusting automatically).

2. In reality the focus and aim direction are brought together is a single operation rather than strictly sequentially as above.

B

Fig 1: Fishing Scope Deign Components Viewer -Used to aim the scope at the target by aligning the crosshahs with the target.

Contains a tilt sensor to read the tilt angle of the viewer to the hcrimntai. Tilt angl, data is fed to the computer (or chip) en one parameter for the servo mechanism response. The viewer also has a focus medanlsm with a sensor to read the cunxnt focal distance of the viewer. The user focuses the viewer on the target (or auto focus) then a sensor reads the focal distance and feeds ft to the computer. The focal distance is one of the parameters used to determine the servo mechanism response in order to achieve the required delta' angle.

Gun -1ypical gun, crossbow or other miner device for shooting a projectile.

Servo -The servo mechanism is driven by the computer and is used to pivot the viewer to a relative angle to the gun such that the viewer points at the apparent image of the underwater target while the gun points directly at the target.

Differential Pressure Gauge -Sensor device (usually a tube filled with fluid) to measure the height from one end of the tube to the other. The lower end has a float that floats on the water and may simply contain a pressure sensor to allow it to determine the height to the other end of the Instiwninu. The higher end is attached to the height datum poh* on the gun. An electrical signal is passed from the pressure sensor through a wise in th. tube to the gun computer. The reading is used to determine the servo mechanism movement and therefore the relative delta' angle of the viewer to the gun.

Fig 2: Thblmg Scope Design Parameters H Height from the water line toe datum point on the fishing scope.

Tilt The angleoftheviewertothe horizontal.

dl +d2 -Focal distance of the lain when focused on the underwater target.

Delta The Delta' angle between the alignment of the viewer and the gun, fixed by the servo mechanis*m Note The line extending from the gun shows the path of the projectile to the target The line extending (mm the viewer show the path of the tight from the target, refracted throtaJi the water surface and into the viewer. The Delta angle has been sat by the onboard computer or chip, based on the instnuneni readinge, to make the two lines converge In the fishing scope as the same time.

Claims (3)

1. Claims Patent rights are claimed on the design invention of a special

   telescopic or electronic gun-sight (or scope) for the purpose of shooting underwater targets from above the water surface using integral automated angular alignment adjustment between the projectile (or gun) and the gun-sight (i.e. scope) viewer in order to compensate for water surface-to-air refraction such that after adjustment the viewer is aimed at the apparent image of the underwater target while the projectile is aimed directly at the real underwater target.
2. 2. Patent nghts are claimed on the design invention of a special telescopic or electronic gun-sight (or scope) for the purpose of shooting underwater targets from above the water surface using integral automated angular alignment adjustment between the projectile (or gun) and the gun-sight (i.e. Scope, or viewer) using the following combination of instruments in order to compensate for water surface-to-air refraction such that after adjustment the viewer is aimed at the apparent image of the underwater target while the projectile is aimed directly at the real underwater target The specific instrumentation applied in this solution are the combination of: (I) A sensor to measure the tilt angle of the gun or viewer (2) A sensor to measure the height of the device from the surface of the water. These devices include the use of a differential pressure gauge -i.e. float (for floating on the water surface) and pressure sensor with a tube of fluid attached to the scope, or any use of laser measurement or any other means of measuring the height of the device to water surface.
3. (3) A sensor to measure the distance from the device to the target, including measurement by using the focal distance setting of an optical viewer, whether by manual or automatic focus adjustment, or by using laser distance measurement technology or by using any other means of device to target distance measurement