Spool braking device for fishing reel

A spool braking device and a spool braking method for increasing spool braking capability. The spool braking device includes a reel attached to a fishing rod in a detachable manner. A rotatable spool is arranged in the reel. A fishing line is wound to the spool. A brake mechanism electronically brakes rotation of the spool. An acceleration sensor detects swing acceleration produced when the fishing rod is swung and generates an acceleration signal. A brake control unit determines whether or not the spool needs to be braked based on the acceleration signal and drives the brake mechanism.

BACKGROUND OF THE INVENTION

The present invention relates to a spool braking device for a double bearing reel.

A typical double bearing reel includes a reel body, which is attached to a fishing rod, and a line winding spool, which is attached to the reel body in a rotatable manner. When used by a person, such as a beginner, who is not accustomed to a double bearing reel (hereinafter referred to as “reel”), a backlash may be produced when casting the fishing line.

Normally, backlash is produced when the spool rotates at a speed that is higher than the speed at which the fishing line is drawn out of the spool (hereinafter referred to as “line speed”). More specifically, when the spool rotation speed exceeds the line speed, the spool overly continues to rotate even after the fishing line hits water. This entangles the fishing line in the spool.

To prevent such backlash, for example, U.S. Pat. No. 5,833,156 discloses an automatic brake system controlled by a microcomputer. The automatic brake system includes a rotation detector, which detects the rotation speed of the spool, an acceleration sensor, which detects the line speed, and a brake mechanism, which uses magnetic force to control the rotation speed of the spool. When the spool rotation speed exceeds the line speed, the microcomputer drives the brake mechanism and increases the spool braking force. The microcomputer also determines when the fishing line will hit water from a detection value of the line speed to apply full braking on the spool.

However, in the above-described prior art that controls the braking of the spool just by detecting the line speed and the spool rotation speed, there is a limit to the braking capability. Particularly, in the prior art, the acceleration sensor is connected to the fishing line. Accordingly, the acceleration sensor detects the line speed only when the fishing line is being cast. Further, there is another example in the prior art in which a height sensor is used in lieu of the acceleration sensor. However, the height sensor also detects only the line speed. Thus, in each prior art example, spool braking is performed only when the spool rotation speed exceeds the line speed or when the fishing line hits water (i.e., line speed becomes zero). Further, in the prior art, the braking timing for when the fishing line hits water is determined from the detection of the line speed. Therefore, backlash prevention control is performed after the fishing line actually hits water. This slightly delays the timing in which backlash prevention control is actually performed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a spool braking device and a spool braking method that increases spool braking capability.

One aspect of the present invention is a spool braking device for a fishing reel attached to a fishing rod in a detachable manner for use with a fishing line. The spool braking device includes a rotatable spool arrangeable in the reel for winding with the fishing line. A brake mechanism electronically brakes rotation of the spool. An acceleration sensor detects swing acceleration produced when the fishing rod is swung and generates an acceleration signal. A brake control unit drives the brake mechanism. The brake control unit determines whether or not to brake the spool based on the acceleration signal.

A further aspect of the present invention is a fishing device for use with a fishing line. The fishing device includes a fishing rod and a fishing reel attached to the fishing rod in a detachable manner. The fishing rod includes an acceleration sensor for detecting swing acceleration produced when the fishing rod is swung and generating an acceleration signal. The reel includes a spool for winding the fishing line, a brake mechanism for electronically braking rotation of the spool, and a brake control unit for driving the brake mechanism. The brake control unit determines whether or not the spool needs to be braked based on the acceleration signal.

Another aspect of the present invention is a method for controlling braking of a rotatable spool arranged in a fishing reel. The reel is attached to a fishing rod in a detachable manner, and the reel includes a brake mechanism for electronically braking rotation of the spool. The method includes generating an acceleration signal using an acceleration sensor to detect swing acceleration produced when the fishing line is swung, and driving the brake mechanism by determining whether or not to brake the spool based on the acceleration signal.

A fishing device10equipped with a preferred embodiment of a spool braking device according to the present invention will hereinafter be discussed with reference to the drawings.FIG. 1is a schematic diagram entirely showing the fishing device10, which includes a fishing rod (hereinafter referred to as “rod”)12and a double bearing reel (hereinafter referred to as “reel”)14. The reel is attached to the rod12in a detachable manner.

Referring toFIG. 1, the reel14is attached to a basal portion22of the rod12. A power supply terminal and a communication terminal (not shown) are incorporated in the basal portion22of the rod12.

An acceleration sensor32is arranged at a distal portion24of the rod12. When the reel14is attached to the rod12, a power supply device (not shown), which is arranged in the reel14, supplies power to the acceleration sensor32via the power supply terminal. The acceleration sensor32is preferably a tri-axial capacitance type acceleration sensor, which detects acceleration in the directions of an x-axis, y-axis, and z-axis. The acceleration sensor32is connected to the control system in the reel14by a signal wire (not shown), which extends through a rod body26.

The reel14includes a reel body42, a rotatable spool44arranged on the reel body42, a microcomputer46(FIG. 2) incorporated in the reel body42, a rotation sensor48(FIG. 2) for detecting rotation of the spool44, and a brake mechanism50(FIG. 2) for electronically braking rotation of the spool44. The reel14also includes a user interface52(FIG. 2) for setting the operation of the microcomputer46. Although not shown, the reel14also includes a handle for manually rotating the spool44, a clutch lever for selectively switching the spool44between a free state and a locked state4, and a mechanical brake for adjusting the rotation degree of the spool44.

A fishing line16is wound around the spool44. The fishing line16has a basal end fixed to the spool44and a distal end (free end) drawn out of the spool44, and guided to the distal end of the rod12through a group of guides18arranged on the rod12. As shown inFIG. 1, a weight20such as lure is attached to the distal end of the fishing line16drawn out of the rod12.

FIG. 2is a schematic block diagram showing a spool braking device60in the preferred embodiment. The microcomputer46includes a memory62and a timer64. The memory62stores a spool braking program, which contains a group of commands executable by the microcomputer46, and a group of initial parameters used by the microcomputer46when executing the program. The memory62also stores a group of control parameters obtained by the microcomputer46when executing the program. The microcomputer46executes the spool braking program and uses acceleration information from the acceleration sensor32to drive the brake mechanism50. In addition to the acceleration information from the acceleration sensor32, the microcomputer46may use rotation information from the rotation sensor48when driving the brake mechanism50. Accordingly, the microcomputer46functions as a brake control unit. The microcomputer46also uses the acceleration information to calculate an estimated casting distance Xd, which is the distance from a casting point where the user casts the fishing line16(including the weight20) to a landing point where the fishing line16lands on water (hereinafter referred to as “landing point”). Based on the estimated casting distance Xd, the microcomputer46drives the brake mechanism50.

The rotation sensor48detects rotation of the spool44and generates a rotation signal Sr. A magnetic sensor, an optical sensor, or the like may be used as the rotation sensor48. The microcomputer46determines the rotation speed Vs of the spool44based on the rotation signal Sr from the rotation sensor48. The spool rotation speed Vs relates to the actual cast amount of the fishing line16drawn out of the spool44.

The brake mechanism50electronically brakes rotation of the spool44in response to a drive control signal Sd from the microcomputer46. The magnet brake mechanism50may be formed by a plurality of magnets that apply magnetic torque to the spool44to adjust the rotation speed.

When the user swings the rod12, the acceleration sensor32, which is arranged at the distal portion24, detects the swing acceleration and generates an acceleration signal Sa. When the fishing line16is cast, the microcomputer46monitors the user's swing motion based on the acceleration signal Sa from the acceleration sensor32. During the casting, the microcomputer46calculates a plurality of control parameters, which include an initial speed V0, projection angle θ, spool rotation initiation period Ts, estimated line speed VL, estimated cast line amount DL, and estimated casting distance Xd of the fishing line16(including the weight20such as lure) based on the monitor result. The initial speed V0is the speed the fishing line16(weight20) is cast from the rod12when the rod is located at a casting swing termination position. The projection angle θ is the angle at which the fishing line16(weight20) is cast from the rod12at the casting swing termination position. The spool rotation initiation period Ts is the expected period from when the casting swing of the rod12is terminated to when the spool44starts to rotate. The estimated line speed VLis the estimated speed of the fishing line16that is being cast. The estimated cast line amount DLis the estimated cast amount of the fishing line16drawn out of the spool44at the estimated line speed VL. The estimated casting distance Xd is the casting distance of the fishing line16from the casting point to the landing point.

The user interface (hereinafter referred to as “UI”)52includes a reset button54for initializing the operation of the microcomputer46. When the user pushes the reset button54, the microcomputer46resets output information (Sa, Sr) of the acceleration sensor32and the rotation sensor48. Further, when the reset button54is pushed, the microcomputer46stores in the memory62the height level of the rod12as water surface level Yw (e.g., “0”).

The UI52further includes a plurality of parameter switches56manually operated by the user to input and set the group of initial parameters. The user may change the casting conditions (i.e., initial parameter group) by operating the parameter switches56. Accordingly, the UI52serves as a parameter setting unit. In the preferred embodiment, the UI52includes three parameter switches56for setting a height parameter C1, a mass parameter C2, and a weather parameter C3, respectively. Although not shown in the drawings, the UI52also includes a start button.

The height parameter C1indicates the height (hereinafter referred to as “initial height”) of the distal portion24of the rod12from the water surface level Yw when the rod12is located at the casting swing termination position. That is, the initial height is the height level of the rod12when the fishing line16is cast from the rod12. The parameter switch56for setting the height parameter C1may be configured so as to enable the initial height to be set at any value or to enable adjustment of the initial height in fixed steps.

The mass parameter C2indicates the mass of the weight20attached to the fishing line16. The parameter switch56for setting the mass parameter C2may be configured so as to enable the mass of the weight20to be set at any value or to enable adjustment of the mass in fixed steps.

The weather parameter C3indicates weather conditions such as the wind direction, wind speed, weather, and the like. In the preferred embodiment, the microcomputer46recognizes the weather parameter C3as an air resistance coefficient. The parameter switch56for setting the weather parameter C3includes a plurality of preset buttons. When the user pushes a predetermined preset button that corresponds to the weather condition (sunny, rain, wind speed, wind direction, or the like), an air resistance coefficient corresponding to the pushed preset button is stored in the memory62.

The operation of the spool braking device60will now be discussed with reference toFIGS. 3 to 6.FIG. 3is a flowchart summarizing the spool brake control.

Before starting step100, the user initializes the spool braking device60as described below.

(A) The rod12is held at a position (e.g., ground surface) that is substantially the same height as the water surface, and the reset button54is pushed to set the water surface level Yw (“0”) in the microcomputer46.

(B) The parameter switches56are operated to set the initial parameters (i.e., height parameter C1, mass parameter C2, and weather parameter C3) in the microcomputer46.

(C) The start button of the microcomputer46is pushed (this operation may be omitted).

In step100, the microcomputer46reads the initial parameters C1, C2, and C3from the memory62when the user pushes the start button.

In step200, the microcomputer46monitors the user's swing motion with the acceleration sensor32.

In step300, based on the monitoring result of the swing motion, the microcomputer46calculates the control parameters (i.e., initial speed V0, projection angle θ, spool rotation initiation period Ts, estimated line speed VL, estimated cast line amount DL, estimated casting distance Xd) used for executing brake control on the spool44.

In step400, the microcomputer46performs a spool braking process, which includes backlash prevention control, based on the calculated control parameters. Step400is continuously performed until the spool rotation speed Vs becomes zero. When step400is completed, the spool brake control ends, and the user starts fishing.

FIG. 4is a flowchart showing the swing monitoring process of step200in detail. In step210, the microcomputer46determines a casting swing initiation position P1of the rod12from the acceleration signal Sa and stores the position P1in the memory62. For example, when the direction of the user facing the casting point is the positive direction, acceleration in the negative direction shifts from a positive value to zero at the position where the user stops the casting swing of the rod12. Therefore, the microcomputer46recognizes the position P1when detecting a change in acceleration in the negative direction.

In step220, the microcomputer determines a casting swing termination position P2of the rod12from the acceleration detection signal Sa and stores the position P2in the memory62. Specifically, when the rod12reaches the casting swing termination position P2, acceleration in the positive direction shifts from a positive value to zero. Therefore, the microcomputer46recognizes the position P2by detecting a change in acceleration in the positive direction.

In step230, the microcomputer46stores in the memory62swing accelerations (Sa) for the X, Y, and Z directions sampled during a swing period in which the rod12was swung from position P1to position P2. Specifically, the microcomputer46samples accelerations for the X, Y, and Z directions in extremely short time cycles (e.g., several milliseconds) during the swing period and stores in the memory62the accelerations sampled in each cycle. Accordingly, the memory62stores each of the sampled accelerations for the X, Y, and Z directions during the swing period in which the rod12is swung from position P1to position P2.

FIG. 5is a flowchart showing the control parameter calculation process of step300in detail. In step310, the microcomputer46uses all of the sampled accelerations stored in the memory62to calculate the initial speed V0and the projection angle θ. As known in the art, speed is obtained by integrating acceleration. In the preferred embodiment, the microcomputer46calculates the speed for each cycle from the corresponding sampled accelerations and the speed of the previous cycle. The same calculation is repeated for each cycle until obtaining the speed at the position P2(i.e., initial speed V0). The microcomputer46then calculates the projection angle θ based on the calculated initial speed V0in the X, Y, and Z directions. Calculations are not limited in such a manner, and the microcomputer46may obtain the initial speed V0by calculating the speed in real time for every sampling cycle.

In step320, the microcomputer46calculates the spool rotation initiation period Ts based on the initial speed V0and the spool rotation speed Vs. Specifically, the microcomputer46sets as a reference time (“0”) the time when the casting swing termination position P2is detected. Then, the microcomputer46estimates the period from the reference time until when the spool44starts to rotate (i.e., Vs>0) based on the initial speed V0. When the weight20is connected to the fishing line16at a distance of about 15 to 20 cm from the distal end of the rod12, and the initial speed V0is 50 km/h (1.3 mm/mS), the microcomputer46calculates the spool rotation initiation period Ts as being about 115 to 154 mS. That is, the microcomputer46predicts that the spool44will start to rotate after about 115 to 154 mS from the reference time. Accordingly, although not shown in the drawings, the microcomputer46determines that a casting error has occurred if rotation of the spool44(Vs>0) is not detected after time Ts elapses. In such a case, the microcomputer46performs spool braking. The spool rotation initiation period Ts may include a margin.

In step330, the microcomputer46uses the two control parameters calculated in step310(initial speed V0and projection angle θ) and three initial parameters (height parameter C1, mass parameter C2, and weather parameter C3) to calculate the estimated casting distance Xd from equations 1 and 2.

Here, g represents the gravitational acceleration and t represents the elapsed casting time. By using equations 1 and 2, the microcomputer46can calculate the estimated casting distance Xd between where the fishing line16(weight20) is cast to where the fishing line16lands on water (i.e., the water surface level Yw is to be zero) irrespective of time t. In equations 1 and 2, the mass parameter C2and the weather parameter C3are used as air resistance parameters. If such air resistance parameters (C2and C3) are not taken into consideration, the microcomputer46may simply calculate the estimated casting distance Xd from equations 3 and 4.

In step340, the microcomputer46measures the elapsed casting time t with the timer64. Further, the microcomputer46uses the initial speed V0, the projection angle θ, the initial parameters (C2and C3), and the elapsed casting time t to obtain the estimated line speed VLfrom the following equation 5.

The calculation of the estimated line speed VLis continuously performed throughout the casting period. If the air resistances (C2and C3) are not taken into consideration, the microcomputer46can simply calculate the estimated line speed VLfrom the following equation 6.
VL=V0cos θ  [Equation 6]

In step350, the microcomputer46obtains the estimated cast line amount DL(DL=VL×t) using the calculated estimated line speed VLand the elapsed casting time t. The calculation of the estimated cast line amount DLis also continuously performed over the casting period.

FIG. 6is a flowchart showing the spool braking process of step400in detail. First, in step410, the microcomputer46determines whether or not the estimated casting distance Xd is greater than or equal to a minimum casting distance Xmin corresponding to the initial speed V0(current calculated value). For example, if the estimated casting distance Xd is extremely short even though the initial speed V0is high, the probability of a casting error occurring is high. Factors causing such a casting error include the projection angle θ being too small. Accordingly, the minimum casting distance Xmin corresponding to the initial speed V0is stored in the memory62of the microcomputer46as a first threshold value. A minimum casting distance Xmin may be set for each initial speed V0. Alternatively, minimum casting distances Xmin may be set in a stepped manner with each corresponding to a plurality of initial speeds within a predetermined range. In step410, if the estimated casting distance Xd is less than the minimum casting distance Xmin that corresponds to the initial speed V0, the microcomputer46executes brake control (step470). Otherwise, the microcomputer46proceeds to step420.

In step420, the microcomputer46determines whether or not the projection angle θ is less than or equal to a maximum projection angle θmax corresponding to the initial speed V0(current calculated value). That is, if the projection angle θ is extremely large even though the initial speed V0is high, the probability of a casting error occurring is high. Accordingly, the maximum projection angle θmax corresponding to the initial speed V0is stored in the memory62of the microcomputer46as a second threshold value. A maximum projection angle θmax may be set so for each initial speed V0. Alternatively, maximum projection angles θmax may be set in a stepped manner with each corresponding to a plurality of initial speeds within a predetermined range. In step420, if the projection angle θ is greater than the maximum projection angle θmax that corresponds to the initial speed V0, the microcomputer46executes brake control (step470). Otherwise, the microcomputer46proceeds to step430.

In step430, the microcomputer46determines the spool rotation speed Vs based on the rotation signal Sr from the rotation sensor48.

In step440, the microcomputer46determines whether or not the estimated cast line amount DLhas become equal to the estimated casting distance Xd. If the estimated cast line amount DLhas become equal to the estimated casting distance Xd, the microcomputer46determines that the fishing line16has landed on water and executes brake control on the spool44(step470). That is, the microcomputer46executes backlash prevention control based on the estimated cast line amount DLand the estimated casting distance Xd. The microcomputer46proceeds to step450if the estimated cast line amount DLis less than the estimated casting distance Xd.

In step450, the microcomputer46determines whether or not the spool rotation speed Vs is greater than the estimated line speed VL. If the spool rotation speed Vs is greater than the estimated line speed VL, the microcomputer46performs the brake control (step470). Otherwise, the microcomputer46proceeds to step460.

In step460, the microcomputer46determines whether or not the spool rotation speed Vs is zero. If the spool rotation speed Vs is zero, the microcomputer46terminates further processing (brake control). Otherwise, the microcomputer46returns to step430. The microcomputer46then repeats step430to step460until the spool rotation speed Vs becomes zero.

The spool braking device60of the preferred embodiment has the advantages described below.

The microcomputer46uses estimates based on the swing acceleration of the rod12to determine whether or not the spool44needs to be braked. This avoids delays in the brake timing.

The acceleration sensor32is arranged at the distal portion24of the rod12. This enables the swing acceleration of the rod12to be accurately detected.

The time until the fishing line16lands on water is predicted from the estimated casting distance Xd. This prevents delays in execution of the backlash prevention control.

The microcomputer46calculates from the swing acceleration of the rod12the plurality of control parameters (initial speed V0, projection angle θ, spool rotation initiation period Ts, estimated line speed VL, estimated cast line amount DL, estimated casting distance Xd) for performing spool braking. Accordingly, the spool braking capability is improved with the use of a single acceleration sensor32.

The microcomputer46drives the brake mechanism50when the estimated casting distance Xd is less than the minimum casting distance Xmin that corresponds to the initial speed V0or when the projection angle θ is greater than the maximum projection angle θmax that corresponds to the initial speed V0. Accordingly, the microcomputer46can perform spool braking while monitoring the casting of the fishing line16.

The height parameter C1indicating the initial height when the fishing line16is cast is set in the microcomputer46. This increases accuracy for calculation of the estimated casting distance Xd.

The mass parameter C2indicating the mass of the weight20and the weather parameter C3indicating the weather condition are also set in the microcomputer46. Thus, the air resistance that is taken into consideration increase accuracy for calculating the estimated casting distance Xd.

The microcomputer46that executes the software is preferably employed as the brake control unit. However, hardware such as ASIC may be employed as the brake control unit.

The acceleration sensor32is most preferably arranged at the distal portion24of the rod12but may be arranged at the central part (rod body26) of the rod12. Alternatively, the acceleration sensor32may be arranged at the basal portion22of the rod12or in the reel14. However, the detection accuracy of the swing acceleration increases when arranging the acceleration sensor32at positions closer to the distal portion of the rod12.

The initial parameters may include a shape parameter indicating the shape of the weight20(e.g., lure shape). The shape of the weight20affects the air resistance. Accordingly, use of the shape parameter would increase accuracy for calculating the estimated casting distance Xd.

A separate acceleration sensor may be arranged in the weight20to detect the actual speed of the fishing line16. In this case, the microcomputer46can recognize the line speed that is more accurate than the estimated line speed VL. This would, however, require a power supply and the implementation of a wireless communication function and thereby increase the volume and mass of the weight20.