WO2004097123A1

WO2004097123A1 - Water closet having automatic water saving system

Info

Publication number: WO2004097123A1
Application number: PCT/KR2004/000941
Authority: WO
Inventors: Jae Tong LEE
Original assignee: Kelim Entech Co., Ltd.
Priority date: 2003-04-25
Filing date: 2004-04-23
Publication date: 2004-11-11

Abstract

The present invention allows a seat cover to be integrally formed with a transmission unit for transmitting a user detection signal in the form of radio signal in a seat cover to facilitate an assembling process and achieve aesthetic appearance, and adopts a radio transmission/receiving mode in which a receiving sensor receives a radio signal from the transmission unit to minimize/receiving error rates originated from line noises in order to prevent erroneous operations as well as leakage and short circuit, thereby improving the reliability of a product. Further, the invention is adapted to supply power if the indoor brightness is at a predetermined value or more but stops power supply if the indoor brightness is the predetermined value or less to prolong the life of a battery, and examines the consumed capacity of the battery to inform the battery replacement time through a voice signal if the remaining capacity is less than a predetermined level so as to facilitate maintenance. The water closet also has a manual lever to be pulled to prevent unnecessary drainage of water through habitual depression of the lever by a user, thereby maximizing the water saving effect.

Description

WATER CLOSET HAVING AUTOMATIC WATER SAVING SYSTEM

Technical Field

The present invention relates to a water closet, and more particularly, a water closet having an automatic water saving system in which a transmission unit mounted inside a seat cover detects a user and transmits a detection signal to a reception unit mounted on a front section of a water tank so that a microcomputer judges the excrement type according to a detection time and flushing water is automatically drained according to the judged excrement type so as to save the consumption of flushing water.

Background Art In general, a water closet has a water tank mounted on a rear portion of a water closet body or bowl, for containing a predetermined amount of flushing water, so that water can be flushed from the water tank into the bowl in response to the operation of a user in order to wash excrement. In a draining system of a water closet which drains flushing water from a water tank into a water closet body or bowl, an opening/closing valve for opening/closing an exhaust port communicating with the water closet body is directly connected to an inside rear part of a control lever mounted outside the tank. When the control lever is manipulated, the opening/closing valve is opened so that flushing water is drained from the water tank into the water closet body to wash the excrement and then closed so that flushing water is fed into and stored in the water tank by a predetermined quantity. In a common water closet of this structure, when a user operates a control lever through a handle to wash inside the bowl, all flushing water contained in the water tank is drained regardless of the excrement type. There occurs an economical problem of in that the amount of flushing water required for washing urine is the same that of flushing water required for washing stool .

In order to solve such a problem occurring in a common water closet as constructed above, there has been disclosed another conventional technique directed to an automatic water saving system of a water closet. Such an automatic water saving system detects the existence of a human body to judge the excrement type such as stool and urine and rotates a siphon cover about the bottom of an overflow pipe to open/close an exhaust port to drain a predetermined quantity of water based upon judged data. The automatic water saving system comprises: a detection unit detachably mounted on the front center of a closet cover and having a built-in waterproof PCB for detecting the existence of a human body and checking the detection time; a drive unit for judging the excrement type according to the time checked by the detection unit and adjusting the rotation angle of a motor to adjust the quantity of flushing water to be exhausted; a support unit for supportably mounting the drive unit on the overflow pipe; a connection unit connected at one end to the drive unit mounted on the support unit and at the other end to an end of a control lever,- for connecting a wire to the siphon cover to be moved in position upward and downward; a power supply detachably attached to the drive unit for supplying power to the motor; and a waterproof cap for wrapping a terminal leaded from the PCB of the detection unit and a power terminal connected to a terminal leaded from the power supply.

The automatic water saving system has an advantage of solving the conventional problems . However, the detection unit for detecting the human body is wiredly connected to the drive unit so that moisture is introduced into a wire, causing a short circuit to the wire or an erroneous operation originated from line noises occurring in signals moving through the wire. Further, there occurs problems in that a risk of electric shock degrades reliability of the product and the management of a wire is difficult, causing inconvenience in use.

The detection unit for detecting a user is steadily powered from the power supply, which results in a waste of power at night in which the water closet is not used often. Because batteries for the power supply have capacities consumed by different quantities, it is difficult to grasp the correct replacement time of batteries and thus the batteries are replaced after the drive unit is stopped, thereby causing a problem in terms of maintenance and repair. There are also problems in that the excrement is collected inside the bowl or the water closet is operated manually, giving inconvenience to users.

Further, when a user habitually presses a handle mounted on the outside wall of the water tank, the control lever rotates the siphon cover upward to drain flushing water out of the water tank, thereby wasting flushing water and reducing an automatic water saving effect .

Furthermore, when the rotation angle is increased owing to a gap occurring during the rotation of the motor of the drive unit as a product is used for a long time period, flushing water is not drained at a precise quantity, to thereby degrade the reliability of the product.

Disclosure of the Invention

The present invention has been made in view of the foregoing problems and it is therefore an object of the present invention to provide a water closet having an automatic water saving system, in which a seat cover is integrally formed with a transmission unit for transmitting a user detection signal in the form of radio signal to facilitate an assembly process and omits a wire exposed to the outside to achieve aesthetic appearance, and adopts a radio transmission/receiving mode in which a receiving sensor receives a radio signal from the transmission unit to minimize transmission/receiving error rates originated from line noises in order to prevent erroneous operations as well as leakage and short circuit, thereby improving the reliability of a product .

It is another object of the present invention to provide a water closet having an automatic water saving system, which supplies power if the indoor brightness is at a predetermined value or more but stops power supply if the indoor brightness is the predetermined value or less to prolong the life span of a battery, and examines the consumed capacity of the battery to inform the battery replacement time through a voice signal if the remaining capacity is less than a predetermined level so as to facilitate maintenance. The water closet also has a manual lever to be pulled to prevent unnecessary drainage of water through habitual depression of the lever by a user, thereby maximizing the water saving effect.

According to an aspect of the invention for realizing the above objects, there is provided a water closet having an automatic water saving system and a water tank mounted on a top of a bowl, comprising: a water tank mounted on a top of a bowl; a seat cover having a transmission unit installed therein, the transmitting unit emitting a human body sensing signal, detecting the existence of a user based upon a reflection signal from a human body, and transmitting a radio signal informing the detection of the human body; a reception unit installed in an installation hole formed in a predetermined position in a front portion of the water tank, for receiving the radio signal transmitted from the transmission unit; a drive unit for inspecting the radio signal received in the reception unit to determine the excrement type from the user, rotating a deceleration motor to drain flushing water by a preset quantity according to the- determined excrement type, and inspecting the remaining capacity of a power-supplying battery with a voltage detector to inform the replacement time of the battery if the remaining capacity is a predetermined level or less; a holder mounted at an upper portion of an overflow pipe for supporting the drive unit; and a manual lever mounted at an upper side of the water tank, and adapted to be operated to drain flushing water by an manual operation even upon the interruption of power to the drive unit but only when pulled by the user after having eased nature to prevent unintentional manipulation by the user.

Brief Description of the Drawings The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which: FIG. 1 is a perspective view of a water closet according to the invention; FIG. 2 is a perspective view illustrating the inside construction of the water closet according to the invention;

FIGS. 3A and 3B are illustrations of a transfer section and a seat cover of the water closet according to the invention, in which FIG. 3A is an exploded perspective view thereof, and

FIG. 3B is a sectional view thereof;

FIGS. 4A and 4B are illustrations of a receiving section of the water closet according to the invention, in which FIG. 4A is an exploded view thereof, and FIG. 4B is a sectional view illustrating the installation state thereof;

FIG.5 is an exploded perspective view illustrating a drive section of the water closet according to the invention;

FIG. 6 is .an exploded perspective view illustrating a holder of the water closet according to the invention; FIGS. 7A and 7B are illustrations of a manual lever according to the invention, in which FIG. 7A is an exploded perspective view thereof, and FIG. 7B is a sectional view thereof ;

FIGS. 8A and 8B are illustrations of a saving system in use according to the invention, in which FIG. 8A illustrates automatic flushing water drain, and FIG. 8B illustrates manual flushing water drain; and

FIG. 9 is a perspective view illustrating another embodiment of the invention.

Best Mode for Carrying Out the Invention

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, in which FIG. 1 is a perspective view of a water closet according to the invention, and FIG. 2 is a perspective view illustrating the inside construction of the water closet according to the invention. The present invention provides a water closet 10 having an automatic water saving system. The water closet 10 includes : a water tank 20 mounted on a top of a bowl 11, a seat cover 200 having a transmission unit 100 installed therein, the transmitting unit 100 emitting a human body sensing signal, detecting the existence of a user based upon a reflection signal from a human body, and transmitting a radio signal informing detection of the human body, a reception unit 300 installed in an installation hole 310 formed in a predetermined position in a front portion of the water tank 20 and for receiving the radio signal transmitted from the transmission unit 100, a drive unit 400 for inspecting the radio signal received in the reception unit 300 to determine the excrement type from the user, rotating a deceleration motor 420 to drain flushing water by a preset quantity according to the determined excrement type, and inspecting the remaining capacity of a power-supplying battery with a voltage detector to inform that the battery is to be replaced if the remaining capacity is a predetermined level or less, a holder 500 a holder 500 mounted at an upper portion of an overflow pipe 21 for supporting the drive unit 400, and a manual lever 600 mounted at an upper side of the water tank, and adapted to be operated to drain flushing water by an manual operation even upon the interruption of power to the drive unit 400 but only when pulled by the user after having eased nature to prevent unintentional manipulation by the user

The water closet 10 will be described in more detail as follows :

As shown in FIGS. 3A and 3B, the transmission unit 100 includes: a transmitter 110 having a transmission member 111 for emitting the radio signal to detect the user who wants to ease nature in the water closet 10 and a reception member 112 for receiving the radio signal from the transmission member 111 in response to reflection of the radio signal from the user, a brightness sensor 120 arranged adjacent to the transmitter 110 and adapted to detect indoor brightness to supply power if the indoor brightness is a predetermined brightness level or more and interrupt power if the indoor brightness is the predetermined brightness level or less, a battery 130 for supplying power to the transmitter 110, and a housing 140 for receiving the transmitter 110 and the battery 130 therein.

As shown in FIGS. 3A and 3B, the seat cover 200 includes a space 210 for receiving the housing 140 of the transmission unit 100 and having opposed guide ribs 211 formed therein, a guide space 220 provided in a top end of the space 210 and having a window 221 for allowing the radio signal to be transmitted/received therethrough, an opening/closing section 230 in tight contact with the guide ribs 211 for opening/closing the inside of the space 210, and a pair of opposed fixing pins 240 for fixing the opening/closing section 230 to the guide ribs 211.

The opening/closing section 230 includes the opening/closing section 230 includes: a pair of opposed fixing holes 231 formed collinear with the opposed fixing pins 240, a pair of opposed sliding spaces 232 for housing the outer peripheries of the opposed fixing holes 231 and communicating with lateral ends thereof, and a pair of opposed sliding pieces 233 arranged movable within the opposed sliding spaces 232 to accept the top ends of the opposed fixing pins 240.

Also, as shown in FIGS. 4A and 4B, the reception unit 300 includes: a support member 330 having a recess 331 formed at one end thereof for seating a receiver sensor 320 for receiving a signal transmitted from the transmission unit 100, a waterproof rubber ring 340 fit around the outer circumferential surface of the support member 330, a fastening member 360 protruded inwardly from the water tank and inserted into a fixing ring 350, which is in tight contact and collinear with the installation hole 310 of the ^"water tank 20, for receiving the support member 330 therein and shutting the inflow of moisture thereto by means of the waterproof rubber ring 340, a fixing nut 380 fastened to one end of the fastening member 360 in such a manner as to be in tight contact with the inner surface of the water tank with a rubber ring 370 being interposed between the fixing nut 380 and the fastening member 360, and a locking nut 390 coupled to the other end of the fastening member, for preventing separation of the support member 330 from the fastening member 360.

The reception unit 300 is horizontally mounted with respect with a cover of the water tank 20.

As shown in FIG. 5, the drive unit 400 controls the output of sound if the radio signal received from the reception unit 300 is a user detection signal, and includes: a deceleration motor 420 rotated forward and backward by a microcomputer 410 for judging the excrement type; a housing 430 for receiving the deceleration motor 420 therein, the housing having a seating member 440 mounted at one side of the outer circumferential surface thereof, the seating member 440 opened laterally, upwardly and downwardly, and having a concave wall which is in close contact with one side of the outer circumferential surface of the housing and has a control projection 443 formed thereon, a pair of opposed lateral walls extended laterally from both ends of the concave wall and having seating grooves 441 formed thereon, wherein an installation space 442 is defined between the concave wall and the opposed lateral walls; a cover 460 coupled to one end of the housing 430 for sealing the inside of the housing 430 and preventing separation of the deceleration motor 420 from the housing 430, and having a reed switch 450 mounted therein for adjusting the rotation angle of the deceleration motor 420 according to the excrement type judged by the microcomputer 410; a reel 470 rotated at the same rotation speed as that of the deceleration motor 420 according to the excrement type; a magnet 480 internally mounted on the reel 470 so that the deceleration motor 420 stops its rotation and returns to the original position under the control of the microcomputer 410 when the magnet 480 is located collinear with the reed switch 450; and a power supply 490 for supplying power to the microcomputer 410 and the deceleration motor 420. As shown in FIG. 6, the holder 500 includes: a clip 510 opened at one side and mounted on the outer circumferential surface of the overflow pipe 21; a fixing member 520 for fixing the clip 510 to the overflow pipe 21; a support member 530 formed integrally with the clip 510 to be extended vertically, and having a guide piece 532, hooks 531 projected beyond top and bottom ends of the clip 510 and guide and support projections 533 and 534 formed on both opposite sides of the guide piece 532 at an equal height, wherein the support member 503 is mounted onto the seating member 440 of the drive unit 400; and an auxiliary support member 540 inserted into the clip 510 if the overflow pipe 21 has a smaller diameter than that of the clip 510.

As shown in FIGS.7A and 7B, the manual lever 600 includes: a fixing member 610 perforated through the inside, having opposed fixing projections 611 projected from a rear end of the fixing member 610; a tight contact member 620 mounted around a front end of the fixing member 610, to be in tight contact with the installation hole 310 of the water tank 20; a handle 630 detachably mounted on the outer periphery of the tight contact member 620 for covering the front end of the fixing member 610, and having a guide hole 631 and a fixing space 632 being integrally formed inside thereof; a first support member 640 mounted around the outer periphery of the fixing member 610 to be in tight contact with an inside face of the water tank 20; a fixture 650 fixedly mounted around the outer periphery of the fixing member 610 to be in tight contact with the support member 640 for preventing separation of the support member 640 from the fixing member 610; a second support member 660 internally hollow and coupled at one end to the rear end of the fixing member 610, the second support member having a pair of vertically opposed support holes 661 formed at one end portion thereof such that the opposed fixing projections 611 of the fixing member 610 are fit into the opposed support holes 661 of the second support member 660 upon the coupling of the second support member 660 to the fixing member 610, and a locking protrusion 662 formed on the inner circumferential surface thereof; a spring 670 inserted into the support member 660 and pressed at one end against the locking protrusion 662; a stopper 680 mounted into the other end portion of the second support member 660 for preventing separation of the spring 670 from the inside of the second support member 660; and a wire W fixed at the fixing space 632 of the handle 630 via the inside of the stopper 680.

Hereinafter an assembling process of the water closet and its operation will be described.

The infrared transmitting and receiver members 111 and 112, the transmitter 110 and the brightness sensor 120 are assembled to a PCB, which is in turn mounted inside the housing 140 in a fashion to powered from the battery 130 thereby to complete an assembling process of the transmission unit 100.

The housing 140 of the transmission unit 100 is moved into the space 210 of the seat cover 200, and the opening/closing section 230 with the sliding pieces 233 being placed at the end of the sliding space 232 is pressed against the space 210 so that the opening/closing section 230 is in tight contact with the guide ribs 211 and at the same time the fixing pin 240 is inserted into the fixing hole 231 of the opening/closing section 230 to be fixed to the guide ribs 211. Then, the seat cover 200 is rotatably mounted on the bowl 11.

In the meantime, after the clip 510 of the holder 500 is placed at the top end of the overflow pipe 21 and the fixing member 520 is hooked on the clip 510 to be fixed to the overflow pipe 21, the seating member 440 of the housing 430 is mounted on the support member 530 of the holder 500.

At this time, the guide projections 533 are inclose contact with ends of the seating grooves 441 of the seating member 440 to be placed in the installation space 442 as soon as the seating grooves 441 are coupled with the guide piece 532 of the support member 530. When the seating member 440 is moved downward at a predetermined distance along the guide piece 532, the control projection 443 of the seating member 440 is caught by the top of the support projection 534 and stops movement, and the hooks 531 of the support member 530 are in tight contact with the top of the seating grooves 441 and fixed thereto.

Where the overflow pipe 21 has a small diameter, the auxiliary support member 540 can be mounted and coupled inside the clip 510. Upon completing the assembling process as above, the transmission unit 100 is powered from the battery 130, and the drive unit 400 is powered from the power supply 490.

The transmission member 111 transmits a radio signal using the power supplied as above, and the receiving member 112 receives signals reflected from those moving through a toilet, a cleaner cleaning the seat cover 200 and a user who actually uses the water closet . Because those moving through the toilet or the cleaner do not ease nature with the water closet 10, there is set a reference time of about 10 seconds. If it is detected that a human body has moved within 10 seconds, flushing water is not drained. If a user is still detected after 10 seconds, it is regarded that the user uses the water closet to ease nature.

That is, the transmission member 111 transmits a radio signal , and the receiving member 112 receives a reflection signal from the user seated on the bowl 11 to ease nature. The received human body detection signal is transmitted from the transmitter 110 as a radio signal, and then received by the receiver sensor 320 of the reception unit 300.

The human body detection signal received by the reception unit 300 is sent to the microcomputer 410 of the drive unit 400, and a melody is outputted to the outside under the control of the microcomputer 410.

A chip storing a plurality of melodies is controlled by the microcomputer 410 to reproduce the melodies in turn, and more various melodies can be reproduced by replacing the chip. The microcomputer 410 examines the duration time of the human body detection signal, and if the user is not detected during the examination of the human body detection time, judges the excrement type such as stool or urine based upon the detection time examined up to the present. For example, if the user detection time is less than 1 minute, the excrement type is judged urine, and 1 minute or more, the excrement type is judged stool.

In this case, the human body detection signal can be transferred in the form of a radio signal of AM/FM mode or an infrared ray signal . It is preferable to use the infrared ray signal of the highest reliability in transmission/receiving. If the microcomputer 410 judges the excrement type based upon the above principle, the deceleration motor 420 is driven clockwise under the control of the microcomputer 410 as shown in FIG. 8A. The deceleration motor 470 is driven clockwise together with the reel 470 to wind the wire W connected to the reel 470 to rotate a siphon cover 22 about the bottom of the overflow pipe 21 to open an exhaust port of the water tank 20 so that flushing water is drained from the water tank 20 into the bowl 11 to wash the excrement.

Further, the magnet 480 mounted on the reel 470, which is driven clockwise, is positioned collinear with the reed switch 450 fixed inside the cover 460, the deceleration motor 420 stops rotation and then is rotated counterclockwise under the control of the microcomputer 410 to return the siphon cover 22 to the original position.

The siphon cover 22 can drain flushing water by different quantities according to the duration time in which the siphon cover 22 is raised since the deceleration motor 420 is rotated at different angles according to the excrement type.

If the deceleration motor 420 is rotated counterclockwise, the reel 470 is driven counterclockwise to unwind the wire W connected to the reel 470 while the siphon cover 22 rotates under the self-weight about the bottom of the overflow pipe 21 to close the exhaust port of the water tank 20. Then, when flushing water is supplied and contained in the water tank 20, a next operation can be carried out .

While the present invention uses the deceleration motor 420 which rotates clockwise or counterclockwise to open the siphon cover 22 or return it to the original position under the control of the microcomputer 410, it is intended to be exemplary only. Alternatively, a stepping motor as another embodiment can be operated in the same manner as the deceleration motor 420. Furthermore, during the standby step of a next operation, the brightness sensor 120 detects the indoor brightness. If the brightness is low or it is night, the power is automatically stopped to save power consumption. If the brightness is high, that is, it is day or a bulb is on, power is normally supplied to each part to convert to a standby position for operation.

The voltage detector examines the remaining capacities of the battery 130 and the power supply 490 of the transmission unit 100, and sends the examined value to the microcomputer 410.

If the remaining capacity of the battery is a predetermined level

(e.g., about 3V) or less, the microcomputer 410 informs the replacement time of battery via a speaker so that the user conceives the battery replacement time from the announcement through the speaker to replace the battery. This relieves the user from additionally examining the remaining capacity of the battery to promote the convenience of the user.

When the battery is exhausted and no longer supplies power, the manual lever 600 mounted on the top of the bowl 10 is pulled as shown in FIG. 8B, the wire W fixed to the fixing space 632 moves outward the water tank 20 along with the handle 630.

At this time, the stopper 60 is moved into the support member 660 along with the wire W while pressing the spring 670 which is caught by the locking protrusion 662 and thus does not move. Movement is stopped after the handle 630 moves a predetermined distance while pressing the spring 670, and the wire W moving along with the handle 630 rotates the siphon cover 22 upward about the bottom of the overflow pipe 21 to open the exhaust port of_the water tank 20 so that flushing water is drained into the bowl 11 from the water tank 20 to wash the excrement .

When the user cancels the pulling force applied to the handle 630 upon completion of the excrement washing operation, the pressed spring 670 moves the stopper 680 outside the support member 660 while closely contacting the handle 630 against the tight contact member 620 under the restoration force. Also, the siphon cover 22 relieved from the pulling force of the wire W rotates downward about the bottom of the overflow pipe 21 under the self-weight to close the exhaust port of the water tank 20, and then flushing water is supplied into the water tank 20 and stored therein as a standby process for the next operation.

While the invention uses the battery as power-supplying means, there may be another embodiment which replaces the battery with an adaptor 710 to supply power. As shown in FIG. 9, a post 700 is mounted inside the water tank 20 to be extended to the outside and a connection terminal 711 of the adaptor 710 is passed through inside the post 700 to supply external power to the drive unit 400.

Further, the drive unit 400 may include a remote controller R for transmitting a mode alteration signal or a control signal . It is possible to initialize the water saving system or to adjust the draining quantity or the magnitude of sound with the remote controller R.

Further, a ball switch is mounted on the bottom of the seat cover 200 to stop power supply when the seat cover 200 contacts the top of the bowl 11 but to supply power when the seat cover 200 is rotated on the top of the bowl 11 tightly contacting the end of the water tank 20.

Industrial Applicability As set forth above, the present invention uses the radio transmission/receiving mode in which the transmission unit transmits the radio user detection signal and the reception unit receives the detection signal . This minimizes transmission/receiving error rates owing to line noises to prevent erroneous operation as well as improve the reliability of a product .

Furthermore, the present invention mounts the ball switch on the bottom of the seat cover to stop power supply if the ball switch contacts the top of the bowl but supply power if the ball switch separates from the top of the bowl . A brightness sensor is mounted inside the transmission unit so that power is supplied if the brightness is at a predetermined level or more but power supply is stopped if the brightness is at the predetermined level or less, so as to minimize the consumption of the battery and prolong the life span and replacement time of the battery, thereby improving economic efficiency. Furthermore, the battery consumption is examined by the voltage detector to inform the replacement time via the speaker if the examined value is a predetermined level (of about 3V) or less so that the user can judge the replacement time of the battery to replace it with a new one. This also provides advantages of easy management and maintenance .

Further, in order to prevent erroneous operation of draining flushing water originated from habitual manipulation of the lever by a user, the lever is improved in structure so that the lever can be operated when it is pulled only. This can prevent any erroneous operation originated from _. habitual depression of the lever to thereby enhance the efficiency of the water saving system as well as provide an advantage that the lever can be manually pulled to drain water in an emergency. Furthermore, the reed switch detects the magnet along with the deceleration motor according to the excrement type and transmits a detection signal to the microcomputer so that the microcomputer precisely control the forward and backward rotation of the deceleration motor to precisely control the quantity of flushing water to be drained.

Claims

What Is Claimed Is:

1. A water closet 10 having an automatic water saving system comprising: a water tank 20 mounted on a top of a bowl 11; a seat cover 200 having a transmission unit 100 installed therein, the transmitting unit 100 emitting a human body sensing signal , detecting the existence of a user based upon a reflection signal from a human body, and transmitting a radio signal informing the detection of the human body; a reception unit 300 installed in an installation hole 310 formed in a predetermined position in a front portion of the water tank 20, for receiving the radio signal transmitted from the transmission unit 100; a drive unit 400 for inspecting the radio signal received in the reception unit 300 to determine the excrement type from the user, rotating a deceleration motor 420 to drain flushing water by a preset quantity according to the determined excrement type, and inspecting the remaining capacity of a power-supplying battery with a voltage detector to inform the replacement time of the battery if the remaining capacity is a predetermined level or less; a holder 500 mounted at an upper portion of an overflow pipe 21, for supporting the drive unit 400; and a manual lever 600 mounted at an upper side of the water tank, adapted to be operated to drain flushing water by an manual operation even upon the interruption of power to the drive unit 400 but only when pulled by the user after having eased nature to prevent unintentional manipulation by the user.

2. The water closet having an automatic water saving system according to claim 1, wherein the transmission unit 100 comprises : a transmitter 110 having a transmission member 111 for emitting the radio signal to detect the user who wants to ease nature in the water closet 10 and a reception member 112 for receiving the radio signal from the transmission member 111 in response to reflection of the radio signal from the user; a brightness sensor 120 arranged adjacent to the transmitter 110 , for detecting indoor brightness to supply power if the indoor brightness is a predetermined brightness level or more and interrupt power if the indoor brightness is the predetermined brightness level or less; a battery 130 for supplying power to the transmitter 110; and a housing 140 for receiving the transmitter 110 and the battery 130 therein.

3. The water closet having an automatic water saving system according to claim 2, wherein the seat cover 200 comprises: a space 210 for receiving the housing 140 of the transmission unit 100 and having opposed guide ribs 211 formed therein; a guide space 220 provided in a top end of the space 210 and having a window 221 for allowing the radio signal to be transmitted/received therethrough; an opening/closing section 230 in tight contact with the guide ribs 211 for opening/closing the inside of the space 210; and a pair of opposed fixing pins 240 for fixing the opening/closing section 230 to the guide ribs 211.

4. The water closet having an automatic water saving system according to claim 3 , wherein the opening/closing section 230 comprises: a pair of opposed fixing holes 231 formed collinear with the opposed fixing pins 240, a pair of opposed sliding spaces 232 for housing the outer peripheries of the opposed fixing holes 231 and communicating with lateral ends thereof, and a pair of opposed sliding pieces 233 arranged movable within the opposed sliding spaces 232 for accepting the top ends of the opposed fixing pins 240.

5. The water closet having an automatic water saving system according to claim 1, wherein the reception unit 300 comprises : a support member 330 having a recess 331 formed at one end thereof for seating a receiver sensor 320 for receiving a signal transmitted from the transmission unit 100; a waterproof rubber ring 340 fit around the outer circumferential surface of the support member 330; a fastening member 360 protruded inwardly from the water tank and inserted into a fixing ring 350, which is in tight contact and collinear with the installation hole 310 of the water tank 20, for receiving the support member 330 therein and shutting the inflow of moisture thereto by means of the waterproof rubber ring 340; a fixing nut 380 fastened to one end of the fastening member

360 in such a manner as to be in tight contact with the inner surface of the water tank with a rubber ring 370 being interposed between the fixing nut 380 and the fastening member 360; and a locking nut 390 coupled to the other end of the fastening member, for preventing separation of the support member 330 from the fastening member 360.

6. The water closet having an automatic water saving system according to claim 1 or 5, wherein the reception unit 300 is horizontally mounted with respect to a cover of the water tank 20.

7. The water closet having an automatic water saving system according to claim 1, wherein the drive unit 400 controls the output of sound if the radio signal received from the reception unit 300 is a user detection signal, and comprises: a deceleration motor 420 rotated forward and backward by a microcomputer 410 for judging the excrement type; a housing 430 for receiving the deceleration motor 420 therein, the housing having a seating member 440 mounted at one side of the outer circumferential surface thereof, the seating member 440 opened laterally, upwardly and downwardly, and having a concave wall which is in close contact with one side of the outer circumferential surface of the housing and has a control' projection 443 formed thereon, a pair of opposed lateral walls extended laterally from both ends of the concave wall and having seating grooves 441 formed thereon, wherein an installation space 442 is defined between the concave wall and the opposed lateral walls; a cover 460 coupled to one end of the housing 430 for sealing the inside of the housing 430 and preventing separation of the deceleration motor 420 from the housing 430, and having a reed switch 450 mounted therein for adjusting the rotation angle of the deceleration motor 420 according to the excrement type judged by the microcomputer 410; a reel 470 rotated at the same rotation speed as that of the deceleration motor 420 according to the excrement type; a magnet 480 internally mounted on the reel 470 so that the deceleration motor 420 stops its rotation and returns to the original position under the control of the microcomputer

410 when the magnet 480 is located collinear with the reed switch

450; and a power supply 490 for supplying power to the microcomputer 410 and the deceleration motor 420.

8. The water closet having an automatic water saving system according to claim 1, wherein the holder 500 comprises: a clip 510 opened at one side and mounted on the outer peripheral surface of the overflow pipe 21; a fixing member 520 for fixing the clip 510 to the overflow pipe 21; a support member 530 formed integrally with the clip 510 to be extended vertically, and having a guide piece 532, hooks 531 projected beyond top and bottom ends of the clip 510 and guide and support projections 533 and 534 formed on both opposite sides of the guide piece 532 at an equal height, wherein the support member 503 is mounted onto the seating member 440 of the drive unit 400; and an auxiliary support member 540 inserted into the clip 510 if the overflow pipe 21 has a smaller diameter than that of the clip 510.

9. The water closet having an automatic water saving system according to claim 1, wherein the manual lever 600 comprises : a fixing member 610 perforated through the inside, having opposed fixing projections 611 projected from a rear end of the fixing member 610; a tight contact member 620 mounted around a front end of the fixing member 610, to be in tight contact with the installation hole 310 of the water tank 20; a handle 630 detachably mounted on the outer periphery of the tight contact member 620 for covering the front end of the fixing member 610, and having a guide hole 631 and a fixing space 632 being integrally formed inside thereof; a first support member 640 mounted around the outer periphery of the fixing member 610 to be in tight contact with an inside face of the water tank 20; a fixture 650 fixedly mounted around the outer periphery of the fixing member 610 to be in tight contact with the support member 640 for preventing separation of the support member 640 from the fixing member 610 and; a second support member 660 internally hollow and coupled at one end to the rear end of the fixing member 610, the second support member having a pair of vertically opposed support holes 661 formed at one end portion thereof such that the opposed fixing projections 611 of the fixing member 610 are fit into the opposed support holes 661 of the second support member 660 upon the coupling of the second support member 660 to the fixing member 610, and a locking protrusion 662 formed on the inner circumferential surface thereof; a spring 670 inserted into the support member 660 and pressed at one end against the locking protrusion 662; a stopper 680 mounted into the other end portion of the second support member 660 for preventing separation of the spring 670 from the inside of the second support member 660; and a wire W fixed at the fixing space 632 of the handle 630 e inside of the stopper 680.