Safety device for toy watercraft

Abstract

A toy watercraft includes a housing and a motor contained within the housing and operatively connected with a propulsion system for propelling the watercraft when the motor is operated. A safety device is constructed and arranged to permit operation of the motor when the watercraft is immersed in water, and prevent operation of the motor when the watercraft is removed from water.

1 . A toy watercraft comprising: 
 a housing;    a motor contained within the housing and operatively connected with a propulsion system for propelling the watercraft when the motor is operated; and    a safety device constructed and arranged to permit operation of the motor when the watercraft is immersed in water, and prevent operation of the motor when the watercraft is removed from water.    
   
   
       2 . The toy watercraft according to  claim 1 , wherein the safety device includes first and second spaced-apart sensors provided on an external surface of the housing, the first and second sensors being arranged such that operation of the motor is determined by a sensed parameter of the first and second sensors.  
   
   
       3 . The toy watercraft according to  claim 2 , wherein the sensed parameter is associated with the watercraft's relation to water such that the operation of the motor is permitted when the first and second sensors are immersed in water, and operation of the motor is prevented when the first and second sensors are removed from water.  
   
   
       4 . The toy watercraft according to  claim 3 , wherein the sensed parameter is a resistance between the first and second sensors.  
   
   
       5 . The toy watercraft according to  claim 4 , wherein operation of the motor is permitted when the resistance between the first and second sensors is relatively low.  
   
   
       6 . The toy watercraft according to  claim 5 , wherein operation of the motor is permitted when the resistance between the first and second sensors is less than about 5 MΩ.  
   
   
       7 . The toy watercraft according to  claim 4 , wherein operation of the motor is prevented when the resistance between the first and second sensors is relatively high.  
   
   
       8 . The toy watercraft according to  claim 7 , wherein operation of the motor is prevented when the resistance between the first and second sensors is greater than about 100 MΩ.  
   
   
       9 . The toy watercraft according to  claim 2 , wherein the first and second sensors are metal rods electrically connected to an application circuit for operating the motor.  
   
   
       10 . The toy watercraft according to  claim 9 , wherein the application circuit includes a comparator that controls operation of the motor based on a resistance between the first and second sensors, the comparator structured to use a difference in conductance between a water medium and an air medium to determine if the watercraft is immersed in water or removed from water.  
   
   
       11 . The toy watercraft according to  claim 10 , wherein the comparator includes the first and second sensors, a diode, a plurality of resistors, and two transistors, the comparator being configured such that (1) a feedback resistance from the first and second sensors smaller than a selected one of the resistors turns the two transistors on to allow activation of the motor, and (2) a feedback resistance from the first and second sensors greater than the selected one of the resistors turns the two transistors off to prevent activation of the motor.  
   
   
       12 . The toy watercraft according to  claim 9 , wherein the first and second sensors are spaced apart from one another a suitable distance to avoid completion of the application circuit by residual water patches that are carried by the housing when the watercraft is removed from water into air.  
   
   
       13 . The toy watercraft according to  claim 1 , wherein the propulsion system includes a propeller.  
   
   
       14 . A safety device for a toy watercraft including a housing and a motor contained within the housing and operatively connected with a propulsion system for propelling the watercraft when the motor is operated, the safety device comprising: 
 first and second spaced-apart sensors provided on an external surface of the housing, the first and second sensors being arranged such that operation of the motor is determined by a sensed parameter of the first and second sensors,    wherein the sensed parameter is associated with the watercraft's relation to water such that the operation of the motor is permitted when the first and second sensors are immersed in water, and operation of the motor is prevented when the first and second sensors are removed from water.    
   
   
       15 . The safety device according to  claim 14 , wherein the sensed parameter is a resistance between the first and second sensors.  
   
   
       16 . The safety device according to  claim 15 , wherein operation of the motor is permitted when the resistance between the first and second sensors is relatively low.  
   
   
       17 . The safety device according to  claim 16 , wherein operation of the motor is permitted when the resistance between the first and second sensors is less than about 5 MΩ.  
   
   
       18 . The safety device according to  claim 15 , wherein operation of the motor is prevented when the resistance between the first and second sensors is relatively high.  
   
   
       19 . The safety device according to  claim 18 , wherein operation of the motor is prevented when the resistance between the first and second sensors is greater than about 100 MΩ.  
   
   
       20 . The safety device according to  claim 14 , wherein the first and second sensors are metal rods electrically connected to an application circuit for operating the motor.  
   
   
       21 . The safety device according to  claim 20 , wherein the application circuit includes a comparator that controls operation of the motor based on a resistance between the first and second sensors, the comparator structured to use a difference in conductance between a water medium and an air medium to determine if the watercraft is immersed in water or removed from water.  
   
   
       22 . The safety device according to  claim 21 , wherein the comparator includes the first and second sensors, a diode, a plurality of resistors, and two transistors, the comparator being configured such that (1) a feedback resistance from the first and second sensors smaller than a selected one of the resistors turns the two transistors on to allow activation of the motor, and (2) a feedback resistance from the first and second sensors greater than the selected one of the resistors turns the two transistors off to prevent activation of the motor.  
   
   
       23 . The safety device according to  claim 20 , wherein the first and second sensors are spaced apart from one another a suitable distance to avoid completion of the application circuit by residual water patches that are carried by the housing when the watercraft is removed from water into air.