Baths – closets – sinks – and spittoons – Wash receptacles – With proximity operated valve
Reexamination Certificate
1999-08-10
2001-08-28
Recla, Henry J. (Department: 3751)
Baths, closets, sinks, and spittoons
Wash receptacles
With proximity operated valve
C250S2140RC, C250S221000, C251S129040
Reexamination Certificate
active
06279179
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a control circuit for initiating flow into a scrub sink and, in particular, to a circuit containing a photo sensitive component mounted on the scrub sink for contact with the torso of the user.
In preparation for performing a medical procedure, a doctor carefully washes his hands before placement of gloves thereon. It is necessary to complete the washing and operate the scrub sink without the use of hands so as to maintain a sterile condition. To enable the washing operation to be conducted without direct contact of the hands with the flow control mechanism or scrub sink, the combination of a light beam and photocell has been utilized. Interruption of the beam by the hands and arms of the doctor initiates flow from the spout. As long as the hands or arms continue to interrupt the beam, the flow continues. This type of device suffers from a significant disadvantage in that the doctor must continually maintain his hands in position to interrupt the beam. Since the beam width determines in part the sensitivity of the device, the use of a narrow beam is favored. Thus, the movement of the hands and/or arms during the scrubbing operation is unduly restricted else the flow of water becomes repeatedly interrupted.
Attempts to direct a beam of light to the torso of the user and monitor changes in reflected light have proven generally unsatisfactory. Changes in ambient conditions along with variations in the type of reflective surface cause the operation of the circuit to be unpredictable. Thus, the monitoring of changes in reflected light levels at or near scrub sinks has not proven satisfactory in these types of flow control devices.
Another approach has utilized an under the sink light beam and reflections sensor to detect the presence of the legs of the user. One such device is disclosed in U.S. Pat. No. 5,412,816 wherein a tubular extension is affixed under the sink for detection of the change in light level caused by the legs of the user being within a few inches of the sensor. The problems arising from changes in ambient conditions are countered by use of a short focus sensor. Thus, the doctor's movements are quite limited else the flow into the sink stops. Other under the sink approaches to providing remote actuation of flow to a scrub sink have relied on leg-actuated levers. These mechanical systems are characterized by the problems inherent in all mechanical devices subjected to repeated use. Furthermore, a doctor using this type of scrub sink actuating system is limited in movement during use since the same position is maintained to insure flow.
The present invention is directed to a dark-initiated flow control circuit which operates essentially independently of the sensitivity of a sensor and does not reply on reflected light levels for operation. The circuit utilizes a light-responsive resistive component mounted on the exterior of the edge adjacent the user. Contact by the torso or masking of the incident light causes the circuit to actuate a valve in the liquid flow line. The circuit permits adjustment for changes in ambient conditions to provide reliable operation. Further, the flow control circuit can be retrofitted on installed scrub sinks without requiring removal or alteration of the scrub sink or its tub.
SUMMARY OF THE INVENTION
In accordance with this invention, a scrub sink providing hands-free user control of the entering fluid includes an electrically-responsive valve located in the liquid flow line to control the flow of liquid through a spout in the tub of the sink.
A light-responsive component having light and dark impedance states is mounted on the exterior of the tub on the edge portion proximate to the user. The position of the cell enables the user to either rest directly against the cell or stand in close proximity thereto thereby permitting lateral movement while maintaining the cell in its dark impedance state.
The invention includes a control circuit containing a differential amplifier circuit. One input signal to the amplifier is derived through the light-responsive component, typically a photosensitive cell, with the other input signal being derived from the voltage across an adjustable resistor. The adjustment of the resistor enables the control circuit to operate under differing ambient conditions. When the user blocks incident light from the photosensitive cell, the differential amplifier provides an output which results in an actuating signal being supplied to the valve in the flow line.
The placement of the photosensitive cell and the use of the dark condition to actuate the valve enables the user to freely move the arms and hands during a scrub without experiencing interruption in flow. Further, the torso can be moved laterally without causing a cessation of flow since the photosensitive cell is considerably smaller than the torso of the user. Thus, the invention greatly enhances the mobility of the user during a scrub and facilitates the process of hands-free scrubbing.
Further features and advantages of the invention will become more readily apparent from the following detailed description of a specific embodiment of the invention when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3505692 (1970-04-01), Forbes
patent: 3670167 (1972-06-01), Forbes
patent: 3862414 (1975-01-01), Algeri
patent: 5033508 (1991-07-01), Laverty, Jr.,
patent: 5170514 (1992-12-01), Weigert
patent: 5868311 (1999-02-01), Cretu-Petra
Nguyen Tuan
Recla Henry J.
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