Fishline length measuring device for fishing reel

A fishline length measuring device adapted to a fishing reel having a spool rotatably supported on a reel body for winding thereon and unwinding therefrom a fishline, said fishline length measuring device comprising:

• first means for detecting a direction of the rotation of the spool and providing a first signal indicative thereof;
• second means for detecting a number of the rotation of the spool and providing a second signal indicative thereof;
• third means for applying an ultrasonic wave beam onto a surface of the fishline wound on the spool and generating a third signal indicating the emission of the ultrasonic wave beam therefrom;
• fourth means for receiving the ultrasonic wave beam emitted from the third means and reflected by the surface of the fishline wound on the spool and generating a fourth signal indicating the reception of the reflected ultrasonic wave beam thereby;
• fifth means for measuring a time period .DELTA.T between the generations of the third signal and of the fourth signal, and providing a fifth signal indicative thereof;
• and
• sixth means for calculating a fishline length wound onto or unwound from the spool due to the rotation of the spool based on the first, second and fifth signals.

A fishline length measuring device adapted to a fishing reel having a spool rotatably supported on a reel body for winding and unwinding a fishline thereon, said fishline length measuring device comprising:

• first means for detecting a direction of the rotation of the spool and providing a first signal indicative thereof;
• second means for detecting a number of the rotation of the spool and providing a second signal indicative thereof;
• third means having at least one ultrasonic wave sensor for applying an ultrasonic wave beam onto a surface of the fishline wound on the spool and receiving the ultrasonic wave beam emitted from the third means and reflected by the surface of the fishline wound on the spool;
• fourth means for applying frequency-modulated sending voltage to said third means to emit the ultrasonic wave beam from said third means and for inducing a reception voltage on said third means when said third means receives the ultrasonic wave beam emitted from the third means and reflected by the surface of the fishline wound on the spool;
• fifth means for mixing said sending voltage and said reception voltage with each other to generate a beat signal and providing a third signal indicative of a frequency fr of the beat signal;
• and
• sixth means for calculating a fishline length wound onto or unwound from the spool due to the rotation of the spool based on the first, second and third signals.

A method for measuring a fishline length wound onto and/or unwound from a spool rotated relative to a reel body of a fishing reel, comprising the steps of:

• detecting a direction of the rotation of the spool and providing a first signal indicative thereof;
• detecting a number of the rotation of the spool and providing a second signal indicative thereof;
• detecting a fishline winding diameter D defined by a fishline wound on the spool by applying an ultrasonic wave beam onto a surface of the fishline wound on the spool and receiving the ultrasonic wave beam reflected by the surface of the fishline wound on the spool and providing a third signal indicative of the diameter D;
• and
• calculating the fishline length wound onto and/or unwound from the spool due to the rotation of the spool based on the first, second and third signals.