Touch controlled switch assembly

• US 4,037,221 A
• Filed: 06/06/1975
• Issued: 07/19/1977
• Est. Priority Date: 05/16/1974
• Status: Expired due to Term

• Current Assignee: Jerry L. Alexander
• Original Assignee: Jerry L. Alexander
• Inventors: Alexander, Jerry L.
• Primary Examiner(s): Swann, III, Glen R.
• Application Number:
  US05/584,251
• Time in Patent Office: 774 Days
• Field of Search: 340/274 R, 340/258 C, 240/2.13, 200/DIG. 1, 200/61.62, 200/61.58 R, 307/125, 307/294, 307/116, 307/308, 328/77, 328/5, 317/DIG. 2
• US Class Current: 307/116
• CPC Class Codes: E05B 17/22 Means for operating or controlling lock or fastening device accessories, i.e. other than the fastening members, e.g. switches, indicators E05B39/00 - E05B45/00 take precedence
• CPC Class Codes: G08B 13/26 by proximity of an intruder causing variation in capacitance or inductance of a circuit
• CPC Class Codes: H03K 17/292 in thyristor, unijunction transistor or programmable unijunction transistor switches
• CPC Class Codes: H03K 17/962 Capacitive touch switches

Abstract

A switch assembly which activates an electrical load when it receives a triggering signal through a network coupled between a touch plate and the switch assembly. The network continuously has an incoming signal at the touch plate comprising a noise component which may be of constant or slowly changing amplitude depending upon ambient conditions at the touch plate, and which incoming signal is instantaneously changed when an individual contacts the touch plate. The network is adapted to pass such an instantaneous change in the incoming signal as a triggering signal to activate the electrical load, but to block the incoming signal when it consists only of the noise component even when the amplitude of the noise component changes slowly. The switch assembly may include timing means so that when it receives a triggering signal the electrical load is activated for a predetermined time, and when activated may transmit a signal to a remote receiver. The switch assembly is particularly useful for controlling the entryway light of a building, with the latch in a door controlling access to the entryway adapted to function as the touch plate.

Claims

1. A switch assembly including:

switch means having an input and adapted for being switched from a first state to a second state when a triggering signal having an intensity exceeding a predetermined level is applied at said input;

a network coupled to the input of said switch means and adapted to electrically couple the input of said switch means to a touch plate such that when said switch assembly is energized by a conventional alternating electrical power source, there is at said touch plate an incoming signal comprising a continuously received alternating electrical noise component which may be of constant or slowly changing amplitude depending upon the ambient conditions at the touch plate and which incoming signal is instantaneously changed when an individual contacts the touch plate, wherein said network comprises;

means adapted for referencing the incoming signal to a predetermined reference voltage;

means adapted for integrating a portion of said referenced incoming signal having a time constant such that there is produced a direct current signal of one polarity relative to said predetermined reference voltage and of slightly less potential than the peak to peak potential of the incoming signal when the incoming signal is of constant or slowly changing amplitude such as is produced by the electrical noise component alone and such that a disproportionately small change is produced in the direct current signal when the incoming signal is instantaneously changed in potential such as is caused by an individual'"'"'s contacting the touch plate;

means for summing said referenced incoming signal and said direct current signal to produce a summed signal; and

means for passing as a triggering signal to said switch means only instantaneous changes in portions of said summed signal of polarity opposite said one polarity.

2. A switch assembly according to claim 1 wherein said means adapted for integrating a portion of said incoming signal comprises means adapted for clamping the referenced incoming signal to said predetermined reference voltage to shift said referenced incoming signal portion toward said one polarity and means for integrating the portion of said clamped signal which is of said one polarity.

3. A switch assembly according to claim 1 wherein said network comprises intensifying means having a high impedance input and which is adapted for amplifying the current associated with said resultant signal to provide a triggering signal which exceeds said predetermined level and has sufficient power to activate said switching means.

4. A switch assembly according to claim 1 further comprising means adapted for providing an alternating potential at said touch plate when said assembly is energized by a conventional alternating electrical power source, said potential providing at least a portion of said electrical noise signal and being adapted to be safely grounded by an individual'"'"'s contacting the touch plate, and means for producing an instantaneous change in the incoming signal upon partial grounding of said alternating potential by an individual'"'"'s contacting the touch plate, so that when an individual contacts the touch plate a said instantaneous change in said incoming signal will be produced either by a static electrical charge transferred to the touch plate by the individual or by the individual'"'"'s partially grounding the touch plate.

5. A switch assembly according to claim 1 wherein said switch assembly is adapted to receive incoming signals generally in the frequency range of conventional electrical alternating power sources such as 60 Hertz.

6. A switch assembly according to claim 1, wherein said means for passing comprises:

means for blocking portions of said summed signal of said one polarity to provide a resultant signal having a generally constant or slowly changing peak potential when the incoming signal consists only of the noise component and which resultant signal is instantaneously changed in potential with respect to said generally constant or slowly changing peak potential when the incoming signal is instantaneously changed; and

means for blocking a constant or slowly changing resultant signal and for passing only an instantaneous change in said resultant signal as a triggering signal.

7. A switch assembly according to claim 6 wherein said means for blocking portions provides a pulsating resultant signal and said means for blocking a constant or slowly changing resultant signal comprises:

means for detecting peaks of said pulsating resultant signal to produce a second DC signal of only slightly less potential than the peak potential of the last received pulse of the resultant signal; and

means for capacitively coupling to the input to said switch means as a triggering signal only rapid changes in said second DC signal as are produced when the resultant signal is instantaneously changed in potential by an individual'"'"'s contacting the touch plate.

8. A switch assembly adapted to control an electric light for illuminating the entryway to a building said entryway comprising a wall, a door mounted in said wall for movement between an open and a closed position, and conductive latch means for releasably securing said door in said wall;

said switch assembly being adapted to be mounted in a conventional switch box positioned in said wall adjacent said door;

said switch assembly comprising;

switch means having an input and adapted for being switched from a first state to a second state when a triggering signal having an intensity exceeding a predetermined level is applied at said input and for providing an output signal when in said second state;

a network coupled to the input to said switch means and adapted to electrically couple the input of said switch to a said conductive latch means such that when said switch assembly is energized by a conventional alternating electrical power source, there is at said latch means an incoming signal comprising a continuously received alternating electrical noise component which may be of constant or slowly changing amplitude depending upon the ambient conditions at the latch means and which incoming signal is instantaneously changed when an individual contacts the latch means, said network comprising;

contact means adapted for installation in a said wall in a position for contact by a said latch means to complete electrical coupling between the latch means and said switch means when a door is closed;

means adapted for referencing the incoming signal to a predetermined reference voltage;

means adapted for integrating a portion of said referenced incoming signal having a time constant such that there is produced a direct current signal of one polarity relative to said predetermined reference voltage and of slightly less potential than the peak to peak potential of the incoming signal when the incoming signal is of constant or slowly changing amplitude such as is produced by the electrical noise component alone and such that a disproportionately small change is produced in the direct current signal when the incoming signal is instantaneously changed in potential such as is caused by an individual'"'"'s contacting the latch means;

means for summing said referenced incoming signal and said direct current signal to produce a summed signal; and

means for passing as a triggering signal to said switch means only instantaneous changes in portions of said summed signal of polarity opposite said one polarity;

means coupled to said switch means for controlling the time during which said switch means remains in said second state;

means coupled to receive said output signal and adapted to be connected for controlling the application of electrical power to the electric light; and

means adapted to be coupled to a conventional electrical power source for energizing said switch means, said network and said means for controlling the time.

9. A switch assembly according to claim 8 further comprising means adapted for providing an alternating potential at said latch means when said assembly is energized by a conventional alternating electrical power source, said potential providing at least a portion of said electrical noise signal and being adapted to be safely grounded by an individual'"'"'s contacting the latch means, and means for producing an instantaneous change in the incoming signal upon partial grounding of said alternating potential by an individual'"'"'s contacting the latch means, so that when an individual contacts the latch means said instantaneous change in said incoming signal can be produced either by a static electrical charge transferred to the latch means by the individual, or by the individual'"'"'s partially grounding the latch means.

10. A switch assembly according to claim 8, wherein said means for passing comprises:

means for blocking portions of said summed signal of said one polarity to provide a resultant signal having a generally constant or slowly changing peak potential when the incoming signal consists only of the noise component and which resultant signal is instantaneously changed in potential with respect to said generally constant or slowly changing peak potential when the incoming signal is instantaneously changed; and

means for blocking a constant or slowly changing resultant signal and for passing only an instantaneous change in said resultant signal as a triggering signal.

11. A switch assembly according to claim 10 wherein:

said means adapted for integrating a portion of said incoming signal comprises means adapted for clamping the referenced incoming signal to said predetermined reference voltage to shift said referenced incoming signal portion toward said one polarity, and means for integrating the portion of said clamped signal which is of said one polarity;

said network includes intensifying means having a high impedance input and which is adapted for amplifying the current associated with said resultant signal to provide a triggering signal which exceeds said predetermined level and has sufficient power to activate said switching means;

said means for blocking portions provides a pulsating resultant signal; and

said means for blocking a constant or slowly changing resultant signal comprises;

means for detecting peaks of said pulsating resultant signal to produce a second DC signal of only slightly less potential than the peak potential of the last received pulse of the resultant signal; and

means for capacitively coupling to the input to said switch means as a triggering signal only rapid changes in said second DC signal as are produced when the resultant signal is instantaneously changed in potential by an individual'"'"'s contacting a said latch means.

12. A method for changing the state of an electrical switch means upon contact of an individual with a touch plate at which touch plate there is an incoming signal comprising a continuously received alternating electrical noise component which may be of constant or slowly changing amplitude depending upon ambient conditions at the touch plate and which incoming signal is instantaneously changed when an individual contacts the touch plate, said method comprising:

providing switch means having an input adapted for being switched from a first state to a second state when a triggering signal having an intensity exceeding a predetermined level is applied at said input;

referencing the incoming signal to a predetermined reference voltage;

integrating a portion of the referenced incoming signal to produce a direct current signal of one polarity relative to said predetermined reference voltage and of slightly less potential than the peak to peak potential of the incoming signal when the incoming signal is of constant or slowly changing amplitude such as is produced by the electrical noise component alone and to produce a disproportionately small change in the direct current signal when the incoming signal is instantaneously changed in potential such as by an individual'"'"'s contacting the touch plate;

summing said referenced incoming signal and said direct current signal to produce a summed signal mostly of said one polarity when the incoming signal consists only of the noise component and having a substantial portion of a polarity opposite said one polarity when the incoming signal is instantaneously changed; and

passing as a triggering signal to said switch means only instantaneous changes in portions of said summed signal of polarity opposite said one polarity.

13. A method according to claim 12 further comprising the steps of:

providing an alternating potential at said touch plate, said potential providing at least a portion of said electrical noise signal and being adapted to be safely grounded by an individual'"'"'s contacting the touch plate; and

producing an instantaneous change in the incoming signal upon partial grounding of said alternating potential by an individual'"'"'s contacting the touch plate so that when an individual contacts the touch plate said instantaneous change in said incoming signal will be produced either by a static electrical charge transferred to the touch plate by the individual or by the individual'"'"'s partially grounding the touch plate.

14. A method according to claim 12 wherein said passing step comprise the steps of:

blocking portions of said summed signal of said one polarity to provide a pulsating resultant signal having a generally constant or slowly changing peak potential when the incoming signal consists only of the noise component and which resultant signal is instantaneously changed in potential with respect to said generally constant or slowly changing peak potential when the incoming signal is instantaneously changed;

detecting peaks of said pulsating resultant signal to produce a second DC signal of only slightly less potential than the peak potential of the last received pulse of the resultant signal; and

capacitively coupling to the input to said switch means as a triggering signal only rapid changes in said second DC signal as are produced when the resultant signal is instantaneously changed in potential by an individual'"'"'s contacting the touch plate.