Electronic propeller guard
AssigneeMaruta Electric Boatworks LLC
InventorMarvin A. Motsenbocker
Life of this patent
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Abstract
Electronic methods, devices and kits electronically protect swimmers, animals and other objects in water from propeller strikes, and alleviate propeller damage. Desirable embodiments include continuous ultrasonic sensing and detection by separate sensors to minimize reaction time for stopping internal combustion engine and electric motor driven propellers. Electric boats having direct drive to propellers are particularly amenable for electronic propeller protection. A variety of sensors may be used, including tactile, ultrasonic, galvanometric and infrared sensors. Optionally, the devices and systems can improve performance, safety and economy of boat rental operations by discouraging, limiting and even reporting propeller strikes to a boat custodian, who may be at a different location when the boat is used.
Claims56
A system to limit contact of a propeller having a diameter D with a solid object in a motor driven watercraft comprising:
- (a) at least one sensor that monitors in front of a danger zone, the zone comprising a circular area of diameter D located distance D immediately ahead of the propeller perpendicular to the direction of motion and outputs a signal in response to intrusion of a solid object in the monitored area;
- and
- (b) an activator electric control circuit that stops motor movement upon receipt of the signal from (a);
- and a signal analysis circuit that (i) receives a signal from each of the at least one monitor sensors, (ii) compares the signals and (iii) outputs a signal to indicate detection of an object;
- wherein the signal analysis circuit detects a phase shift in the at least one sensor of (a).
A system to limit contact of a propeller having a diameter D with a solid object in a motor driven watercraft comprising:
- (a) at least one sensor that monitors in front of a danger zone, the zone comprising a circular area of diameter D located distance D immediately ahead of the propeller perpendicular to the direction of motion and outputs a signal in response to detection of intrusion of a solid object in the monitored area;
- and
- (b) an activator electric control circuit that stops motor movement upon receipt of the signal from (a), wherein at least one first sensor comprises a piezoelectric device that continuously emits a sonic vibration and at least one second sensor comprises a piezoelectric device that continuously detects or waits for a reflection of the sonic vibration from the first sensor.
A system to limit contact of a propeller having a diameter D with a solid object in a motor driven watercraft comprising:
- (a) at least one sensor that monitors in front of a danger zone, the zone comprising a circular area of diameter D located distance D immediately ahead of the propeller perpendicular to the direction of motion and outputs a signal in response to intrusion of a solid object in the monitored area;
- and
- (b) an activator electric control circuit that stops motor movement upon receipt of the signal from (a), wherein the activator control circuit changes the polarity of a motor drive circuit.
An electrical control device for suddenly stopping a propeller in a motor driven watercraft, comprising a sensor that detects a solid object near the propeller and a control circuit that can stop or slow the propeller to less than 10 rpm within one second, wherein the sensor triggers the control circuit upon sensing the solid object, the motor is an electric motor and the control circuit reverses the voltage to a circuit of the electric motor.
Dependencies are inferred from the claim text.