Animal toilet usage status management system

1. An animal toilet usage management system for cats, the toilet usage management system including an animal toilet for cats and a management server, wherein

the animal toilet for cats includes;

an upper container whose bottom part has holes formed therein, the holes penetrating the bottom part in a vertical direction,

a lower container configured to receive urine passing through the holes, and

four first weight sensors configured to measure weight of the upper container, the four first weight sensors configured to be not loaded with the urine received by the lower container after passing through the holes,

the management server includes;

a calculating part configured to calculate, based on a change in weight of a combined value of weight measurements measured by the four first weight sensors, a urine amount of an animal, without any second weight sensor configured to measure weight of the lower container, wherein

the combined value of weight measurements is configured to include a variation range due to a sand scratching act of a cat in the animal toilet, and the combined value is configured to be leveled based on the weight measurements measured at a timing before a certain timing included in a duration of the sand scratching act and the weight measurements measured at a timing after the certain timing, when the weight measurements measured at the certain timing has the variation range which is greater than those measured at the timing before the certain timing and measured at the timing after the certain timing, and the corresponding variation range measured at the certain timing occurs in the weight measurement of only one of the four first weight sensors.

2. The animal toilet usage management system for cats claimed in claim 1 , wherein the management server further includes a static state determining part configured to detect, based on the change in weight of the combined value of the upper container, a static state of the animal which has entered the upper container.

3. The animal toilet usage management system for cats claimed in claim 2 , wherein, in a case where the static state is detected, the calculating part is configured to calculate decreased weight as the urine amount, if the weight decreases from a static state start time when the static state starts to an exit start time when the animal starts to exit the upper container.

4. The animal toilet usage management system for cats claimed in claim 2 , wherein, in a case where the static state is detected, the calculating part is configured to calculate increased weight as a feces amount, if the weight increases from an entrance start time when the animal starts to enter the upper container to an exit completed time when the animal completes exiting the upper container.

5. The animal toilet usage management system for cats claimed in claim 4 , wherein the weight at a static state start time when the static state starts is the same as the weight at an exit start time when the animal starts to exit the upper container.

6. The animal toilet usage management system for cats claimed in claim 1 , wherein the calculating part is configured to calculate differential weight as a body weight, the differential weight being a difference between the weight at an exit start time when the animal starts to exit the upper container and the weight at an exit completed time when the animal completes exiting the upper container.

7. The animal toilet usage management system for cats claimed in claim 1 , wherein

a time resolution of a detection function of the four first weight sensors is once every 0.3 to 0.6 seconds.