US3505692A

US3505692A - Proximity control for a lavatory

Info

Publication number: US3505692A
Application number: US668357A
Authority: US
Inventors: Norman A Forbes
Original assignee: American Standard Inc
Current assignee: Trane US Inc
Priority date: 1967-09-18
Filing date: 1967-09-18
Publication date: 1970-04-14
Anticipated expiration: 1987-04-14
Also published as: DE6752422U; CA934855A; GB1181630A; DE1784772B2; FR1580710A; BE720930A; DE1784772A1

Description

United States Patent 3,505,692 PROXIMITY CONTROL FOR A LAVATORY Norman A. Forbes, Louisville, Ky., assignor to American Standard Inc., New York, N.Y., a corporation of Delaware Filed Sept. 18, 1967, Ser. No. 668,357 Int. Cl. A47k 1/04 U.S. Cl. 4--166 19 Claims ABSTRACT OF THE DISCLOSURE A proximity control arrangement for a lavatory utilizing a dual antenna system for sensing the simultaneous presence of the user in front of the lavatory and the positioning of his hands beneath its water faucet. One antenna is disposed in the area beneath the faucet and, after sensing the presence of the users hands, causes the proximity circuit arrangement to turn the water on and to simultaneously switch to a second antenna, secured along the leading edge of the lavatory, for sensing the presence of the user. When the user leaves the lavatory, the proximity circuit arrangement interrupts the water flow; and after a predetermined delay during which the lavatory surfaces drain dry, the circuit switches the apparatus back to sensing with the first antenna in readiness for the next cycle of operation.

The present invention relates to a proximity control system and apparatus for use with a lavatory or other plumbing equipment.

More specifically, the pre ent invention relates to an improved proximity sensing control arrangement for use with a lavatory utilizing a dual antenna system for sensing the presence of a user and automatically operating the lavatory.

Most conventional lavatories include one or more fluid valves which are turned on manually by the user who operates the valving device. In many lavatories in public places, valving devices are often spring-loaded and must be manually held in the on position in order that the water supply continue to flow from the spout. These valving devices do not permit the user the freedom to employ both of his hands simultaneously in washing them beneath the spout. In lavatories located in industrial and commercial areas, the valving devices often become contaminated with dirt, grease or ink while manually operated by the user to wash his hands.

In an attempt to overcome these disadvantages, lavatories have been provided with proximity sensing circuits which are responsive to the hands of the user being inserted beneath the lavatory spout. These lavatories generally utilize a single antenna sensing device which is positioned in an area beneath the water spout and designed to detect the presence of the users hands. After the water is turned on, however, the antenna may be said to have difficulty in distinguishing between the presence of the water in the basin flowing from the spout and the users hands. The water will thus continue to flow from the spout of the lavatory even after the user removes his hands from the basin of the lavatory. In attempts to overcome these ditficulties, a proximity antenna has been mounted on the front or leading edge of the lavatory away from the basin and water supply. Such a lavatory, however, suffers from the disadvantage in that persons who merely pass in front of the lavatory or stand or sway in front to adjust themselves before a .mirror above the lavatory, often turn the water upply on and thus cause an unnecessary wastage of water.

Accordingly, the present invention overcome all of the above mentioned difiiculties by providing an improved ice proximity sen-sing lavatory having a high reliability dual sensing antenna system. The novel lavatory utilizes a first sensing antenna which may be positioned beneath the outlet of the water spout behind the basin of the lavatory. The second antenna may be positioned along the leading edge of the lavatory as, for example, in front of its basin. The second antenna, however, remains normally disconnected from the proximity sensing circuit until the user places his hands beneath the water faucet in the vicinity of the first antenna. The first antenna is geared to equipment which will then cause the proximity sensing circuit to operate a solenoid valve to permit the water to flow from the spout. The proximity circuit will also be geared so as to simultaneously disconnect the first antenna from its input and connect itself to the second antenna positioned at or in the region of the leading edge of the lavatory. The water will continue to flow from the faucet until the user withdraws from the lavatory and is out of the range of the second antenna. The Water flowing in the basin will not affect the proximity sensing circuit since the first antenna has been disconnected from the circuit from the time the water started to flow. After the water from the faucet stops flowing, the proximity sensing circuit arrangement will operate to disconnect the second antenna and reconnect the first antenna to its input in readiness for another cycle of operation.

It is therefore an object according to the present invention to provide an improved proximity control arrangement for use with a lavatory having a dual antenna sensing system responsive to the approach and withdrawal of the user.

It is a further object according to the present invention to provide a proximity control for use with a lavatory which conserves water by operating only when required by the user.

It is another object according to the present invention to provide a proximity control which is simple in design, easy to manufacture and reliable in operation.

Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings which disclose certain embodiments of the present invention. It should be understood, however, that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the invention as to which reference should be made to the appended claims.

In the drawings wherein similar reference characters denote similar elements throughout the several views:

FIG. 1 illustrates the placement of the dual antennas of the proximity control system according to the invention within a lavatory; and

FIG. 2 is a schematic representation, partially in block diagram, of the control circuit of FIG. 1.

Referring to FIG. 1 there is shown a lavatory 10 having a spout 13 disposed over basin 14. A drain 15 is provided at the lowest point within basin 14, preferably beneath the opening of faucet 13 as shown. Secured behind basin 14, along its vertical wall beneath faucet 13, is a first sensing antenna 11, shown in dotted lines. Antenna 11 also include a wire shield 12 surrounding it and secured against the inside wall of the basin. Lavatory 10 also includes a second sensing antenna 21, also shown in dotted lines, secured beneath and behind the leading edge of the lavatory in front of basin 14. Antenna 21 also includes a wire shield 22 surrounding it and secured to the leading edge. Both antennas and their shields may, of course, be concealed within or under the lavatory.

Referring to FIG. 2., there is shown, partly in schematic form, the connection of the antennas 11 and 21 to a proximity sensing circuit 16 capable of detecting antenna capacitance changes. The proximity sensing circuit is of a type that provides a shield or guard terminal which can be used to shield the antenna lead wire from grounded objects. Such a guard circuit is commonly used in sensitive capacitance measurements, and is well known to the art of instrumentation. In such proximity sensing circuits, the shield or guard is not grounded, and objects connected to the shield or guard have negligible effect on the antenna. Apart from the shield or guard terminal, the proximity sensing circuit is one serving merely to respond to changes in capacity to operate a translating device or other apparatus.

Coupled to the output of sensing circuit 16 is a relay 19 having a coil 40 and a contact arm 44. In the de-energized state of relay 19 (as shown), contact arm 44 is disconnected from contact 39. Line power source 18 is connected permanently to the primary winding P of transformer 26. The secondary winding S of transformer 26 is coupled to a conventional full-wave rectifying bridge 25. In addition, a capacitor 24, connected across the D-C terminals of bridge 25, serves as a filter for the rectified current applied to

relay coils

20 and 30 of relays 60 and 70, respectively.

While the circuit of FIG. 2 remains in a de-energized state, i.e., in the condition shown in FIG. 2, the primary winding P of transformer 36 is connected to the contact arm 39 of relay 19, this relay remaining de-energized. Hence, substantially no voltage will be applied by the secondary winding S of transformer 26 to the base-emitter terminals of transistor 52 over the half-wave rectifierfilter circuit which includes rectifier 35, bleeder resistor 33 and capacitor 34. Thus, the base terminal of transistor 52 will draw essentially no current. While transistor 52 remains non-conducting, this condition does not interfere with the conductivity of transistor 53, the base electrode of which can receive current flowing through resistor 55 and hence transistor 53 draws appreciable current at this time. When transistor 52 becomes conductive later in the cycle, the junction of resistor 55 and the collector of transistor 52 are essentially connected to the emitter of transistor 53, and the base current of transistor 53 falls to a very low value so that transistor 53 essentially becomes non-conducting.

While the circuit of FIG. 2 continues to remain in a deenergized state with an appreciable current flowing to the base electrode of transistor 53, the winding 20 of relay 60 will be energized by the fioW of current supplied from transformer 26 over the circuit of rectifier 25, the winding 20 of relay 60, the collector-emitter electrodes of transistor 53 and back through rectifier 25. When the armature 27 of relay 60 is closed against its contact 28, the antenna 11 will be connected to the input terminal 43 of the proximity sensing circuit 16. Hence, the antenna 11 will be ready to respond to a significant change in capacitance arising from a user placing his hands in the vicinity of the faucet 13. The winding 30 of relay 70, which is connected to the transformer 26 and rectifier by a circuit which is parallel to the winding 20 of relay 60, will not be energized by its connection to the collector-emitter circuit of transistor 52 due to the absence of appreciable current flowing to the base of transistor 52. Relay 70 will therefore remain released. Hence, antenna 21 will remain disconnected from the input terminal 43 3f the proximity sensing circuit 16 because of the dis- :onnection of the armature 37 from its contact 38.

The relay coils 20 and may be of any well known :ype, but they are preferably parts of reed relays having :ontacts which are suitable for switching very small currents.

Capacitors

50, 51, 56 and 57 are employed for :ransient voltage suppression.

It will be apparent that, after antenna 11 responds to he presence of part of a users body, the proximity cir- :uit 16 will cause relay 19 to operate. The closure of the :ontact 39 will connect the AC. voltage source 18 to ransformer 36. Rectified current will now flow through the above-noted rectifier-filter circuit, which includes rectifier 35, to the base-emitter circuit of transistor 52, thereby rendering transistor 52 conducting. Relay 70 will now operate and connect the antenna 21 to the input terminal 43 of the proximity circuit 16 via the armature 37 and contact 38 of relay 70.

The circuit of FIG. 2 operates as follows:

When the user approaches lavatory 10 and places his hands in the vicinity beneath faucet 13, the presence of his hands is sensed by the change in capacitance between antenna 11 and ground, causing proximity circuit 16, which is connected thereto via the armature 27 and contact 28 of relay 60, to operate. This energizes relay 19 and solenoid valve 17. As is well known, solenoid valve 17 is connected to and controls the water pipeline connection that feeds faucet 13 so that water will begin to flow into the basin of the lavatory. Any type of solenoid valve will be appropriate for this arrangement of this invention. Contact arm 44 of relay 19 will close its contact 39 and cause coil 30 of relay 70 to be energized by means of transistor 52 over the network connecting transformer 36 to relay coil 30. Antenna 21 will now be connected to the input terminal 43 of proximity circuit 16. Simultaneously, transistor 53 will ceas e conducting and thus will de-energize relay coil 20 so that contact arm 27 will become disconnected from contact 28. Antenna 21 will. continue to sense the presence of the user in front of the lavatory and maintain solenoid valve 17 in an energized condition while the user is in proper position. As soon as the user withdraws from the range of antenna 21, proximity sensing circuit 16 will de-energize solenoid valve 17 and relay coil 40. Hence, antenna 11 will once again become connected to the input terminal 43 of proximity circuit 16 in readiness for the next cycle of operation.

Relays 60 and 70 and their associated circuitry and contacts may be contained within a shielded mounting 42 shown in dotted lines and secured in an accessible position in a chamber or other location beneath or adjacent to lavatory 10. Shielded case 42 is connected at terminal 41 to both

shields

12 and 22 surrounding or supporting the antennas. These connections may be conveniently performed by utilizing shielded coaxial cables having insulated center conductors connected from

terminals

45 and 46 to antennas 11 and 21, respectively.

In an actual embodiment of the present invention, lavatory 10 was constructed from non-conducting material so that both antennas 11 and 21 would be effective through the walls of basin 14 in sensing proximity. Typical component values were chosen as follows:

Transformers 26 and 36-Primary 120 v., secondary 6 v. Capacitors 50 and 510.1 ,uf., 25 v. rating.

Capacitor 24-250 ,uf., 50 v. rating Capacitor 3450 ,uf., 10 v. rating Capacitors 56 and 57-0.01 ,uf., 25 v. rating Relay coils 20 and 30-300 ohm coils Power source 1812O v. AC, 60 cycles Resistor 23-1O ohms Resistors 33, 54-106 ohms Resistor 47,000 ohms In addition, the following capacitance measurements were made at the antennas:

Capacitance of one antenna to ground equals 7.9 pf. Capacitance of one antenna to shield equals 70 pf. Capacitance of shield to ground equals 260 pf.

With the above parameters, each antenna could be adjusted to operate proximity circuit 16 by moving the hand to a distance of approximately 5-6 inches from the antenna.

From the above measurements, it should be noted that by isolating antenna relays and and the shields of the antennas from ground, the electronic hardware mounted close to the antenna will have negligible effect upon the sensitivity of the proximity circuit so long as the shields are between the antennas and grounded hardware. It can be appreciated that if the antenna shields were directly connected to the ground, the sensitivity of the proximity circuit would be greatly reduced.

Thus, the antenna 11 responds to the positioning of the users hands under or within short range of the faucet 13. The proximity circuit 16, under the control of antenna 11, turns on the solenoid valve 17 and, almost simultaneously, disconnects antenna 11 from the sensing circuit 16. The proximity circuit 16 substitutes antenna 21 in place of antenna 11. Antenna 21 will continue to hold the sensing circuit 16 activated until the user leaves the scene of the lavatory 14. When this happens, antenna 21 will be disconnected from sensing circuit 16 and replaced by antenna 11. This restores the status quo for another cyclical sequence.

Shielded case 42, and the outer conductors of the co axial cables connected to shielded case 42, must be connected to the guard terminal mentioned formerly, so that the switching described above can be accomplished without introducing additional capacitance from antenna 11 to ground or from antenna 21 to ground. The purpose of isolating

transformers

26 and 36 is to keep the impedance from shielded case 42 to ground at a high level. In the example of FIG. 2, this shield-to-ground impedance is essentially the primary-to-secondary interwinding capacitance of

transformers

26 and 36.

The arrangement of this invention may obviously be employed to control the operation of the faucet 13 with any number of antenna or capacity combinations, such as 11, 12 and 21, 22. The mechanism may be adjusted to cause the various capacitor combinations to respond to the proximity of different parts of the users body. Unless all capacitances reached predetermined values, the faucet 13 would fail to operate. And the faucet 13 would continue to operate while any one of said capacitances maintained its predetermined value. But when the charge on the latter capacitance receded from its predetermined value, the operation of the faucet 13 would be stopped.

While only certain embodiments of the present invention have been shown and described merely for the purpose of illustration, it will be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

What is claimed is:

1. The combination of a faucet, a plurality of antennas respectively adapted to be exposed to different parts of a users body, each adapted to change in capacitance by a predetermined amount only when the respective part of the users body is in close proximity to said faucet, and means to operate said faucet only when all of the respective antennas are changed in capacitances to predetermined values.

2. The combination according to claim 1 including, in addition, means to release said faucet when the capacitances of said antennas fall below their respective predetermined values.

3. The combination according to claim 1, in which the faucet operating means includes a solenoid valve.

4. The combination of a faucet, a first antenna positioned so as to respond to the proximity of one part of a users body relative to the position of the faucet, a second antenna positioned so as to respond to the proximity of another part of the users body relative to the faucet, means responsive to a predetermined change of said first antenna to operate said faucet, means to maintain the faucet operated for a predetermined time interval and to render the faucet operating means non-responsive to said first antenna, means responsive to a predetermined change of said second antenna to continue said faucet operated until the change of said second antenna is reduced below the latter predetermined change.

5. A combination in accordance with claim 4 in which the faucet operating means includes a proximity sensing ClIClllt.

6. A combination according to claim 5 in which the faucet operating means also includes a solenoid valve.

7. An arrangement for the control of a faucet, comprising two antennas positioned on opposite sides relative to the outlet of said faucet, one of said antennas responding by changes in its capacitance when one part of a users body is in close proximity thereto, and the other antenna responding to changes in its capacitance when another part of a users body is in close proximity thereto, means to operate said faucet when both antennas respond by predetermined changes in capacitance, and means to release the faucet operating means to prevent the flow of fluid from said faucet when both antennas have failed to respond by predetermined changes in capacitance simultaneously to the proximity of both parts of the users body.

8. An arrangement in accordance with claim 7 in which said faucet operating means includes a proximity sensing circuit.

9. An arrangement in accordance with claim 7 in which said faucet operating means includes a solenoid valve.

10. The method of controlling the operation of a faucet the flow path of which is positioned between first and second control elements, which consists in operating the faucet only when a users hand becomes positioned close to said first element, maintaining the faucet operated as long as the users body is positioned close to the second element even while the users hand becomes more widely spaced from the first element, and closing said faucet when the users body becomes more widely spaced from the second element.

11. A proximity control for use with a lavatory for providing an automatic flow of a liquid from its faucet in response to the presence of a user comprising:

a proximity sensing circuit,

valve means coupled to said circuit for controlling the flow of said liquid, and

antenna means coupled to said proximity circuit and disposed within the lavatory for sensing the presence of the body of the user in front of and his hands within the basin of the lavatory.

12. The control as recited in claim 11 wherein said antenna means comprises:

a first antenna normally coupled to said proximity circuit for sensing the presence of the hands of the user within the lavatory basin,

a second antenna for sensing the presence of the user in front of the lavatory, and

means responsive to said first antenna for energizing said second antenna and said valve means and deenergizing said first antenna.

13. The control as recited in claim 12 wherein said first antenna is disposed beneath the faucet and behind the basin wall of the lavatory.

14. The control as recited in claim 13 wherein said second antenna is secured in front of said basin along the leading edge of said lavatory.

15. The control as recited in claim 14 wherein said means for energizing comprises:

switch means coupled to said proximity circuit and responsive to said first antenna for connecting said second antenna to said proximity circuit and disconnecting said first antenna from said circuit.

16. The control as recited in claim 15 wherein said switch means comprises:

a first normally-closed relay for coupling said first antenna to said proximity circuit,

a second normally-open relay for coupling said second antenna to said proximity circuit, and

a master relay responsive to said proximity circuit for opening said first relay, closing said second relay, and operating said valce means in response to the presence of the user within the basin of the lavatory;

a 7 8 and, opening said second relay, closing said first relay References Cited and turning ofi? said liquid when the user withdraws from the proximity of said second antenna. UNITED T T PATENTS 17. The control as recited in claim 16 wherein said 3,033,248 5/ 1962 Rltchle 22276 XR valving means comprises at least one solenoid valve for 3,151,340 10/1964 Teshlma 4-466 5 3,415,278 12/1968 Yamarnoto et a1. 4166 controlling the flow of liquid from said faucet.

18. The control as recited in claim 17 wherein said first and second antennas are electrically isolated from ground MERVIN STEIN Pnmary Exammer G. H. KRIZMANICH, Assistant Examiner potential.

19. The control as recited in claim 18 wherein said first US. Cl. X.R.

and second antenna relays are isolated from ground 10 potential. 22252; 251132