Touch control for electrical apparatus

Claim 2

In combination with a load adapted to be energized from a source of alternating current, a touch or proximity control for energizing the load, said control comprising a touch element for manual engagement by an operator; solid-state bidirectional controllable conduction means connected between said load and the alternating current source, said controllable conduction means including a control terminal; circuit means to deliver a voltage of a first polarity to the control terminal during each positive half cycle of the alternating current and a voltage of a second polarity to the control terminal during each negative half cycle of the alternating current to render said conduction means conductive during each positive and negative half cycle of the alternating current so long as the operator maintains manual engagement with said touch element, said circuit means comprising first solid-state control means connected between said control terminal and said alternating current source and operable, when conductive, to deliver said first polarity voltage, second solid-state control means connected between said control terminal and said alternating current source and operable when conductive to deliver said second polarity voltage, and control circuit means responsive to manual engagement of said touch element to render said first control means conductive during half cycles of said source of a first polarity, and to render said second control means conductive during half cycles of the other polarity; said touch element is a fixed outer plate of a touch assembly including an inner plate separated from the outer plate by an insulating dielectric material; and said inner plate is electrically connected to said control circuit means.

Claim 3

A touch control according to claim 1 wherein said solid-state bidirectional controllable conduction means is a triac.

Claim 4

A touch control according to claim 1 wherein said circuit means includes a resistor and a capacitor connected in series between said touch element and one side of the alternating current source.

Claim 5

A touch control according to claim 1 wherein one of said solid-state control means is a PNP-transistor; and the other of said solid-state control means is an NPN-transistor.

Claim 6

A touch control according to claim 1 wherein said load is a portable tool having a casing including a handle; said touch element is mounted on the handle for convenient engagement by the finger of a hand grasping the handle; and said circuit means is mounted within the handLe.

Claim 7

A touch control according to claim 5 which further includes a shield on said casing movable between a first position in which said touch element is obstructed, and a second position in which said touch element is exposed for engagement by a finger; and means normally urging the shield toward said first position.

Claim 8

A touch control according to claim 6 wherein said shield is hingedly connected to the handle of the casing, and said means urging the shield toward said first position is a spring.

Claim 9

A touch control according to claim 6 wherein said shield is resilient and is secured to said handle adjacent said touch element.

Claim 10

A touch control according to claim 1 wherein said circuit means includes a timing circuit to deliver said voltages to said control terminal a predetermined time after the beginning of each positive and negative half cycle of the alternating current source; said touch element comprising impedance means, the impedance of which varies with the position thereon of the operator''s touch, said touch element impedance means controlling the timing of said timing means to enable the operator to vary the conduction angle of said conduction means by varying the location of touch on said touch element.

Claim 11

In combination with a load adapted to be energized from a source of alternating current, a touch or proximity control for energizing the load, said control comprising a touch element for manual engagement by an operator; solid-state bidirectional controllable conduction means connected between said load and the alternating current source, said controllable conduction means including a control terminal; circuit means including a timing circuit to deliver a voltage of a first polarity to the control terminal a predetermined time after the beginning of each positive half cycle of the alternating current and a voltage of a second polarity to the control terminal a predetermined time after the beginning of each negative half cycle of the alternating current to render said conduction means conductive during each positive and negative half cycle of the alternating current so long as the operator maintains manual engagement with said touch element, said circuit means comprising first solid-state control means connected between said control terminal and said alternating current source and operable, when conductive, to deliver said first polarity voltage, second solid-state control means connected between said control terminal and said alternating current source and operable when conductive to deliver said second polarity voltage, and control circuit means responsive to manual engagement of said touch element to render said first control means conductive during half cycles of said source of a first polarity, and to render said second control means conductive during half cycles of the other polarity; said touch element comprising impedance means, the impedance of which varies with the position thereon of the operator''s touch, said touch element impedance means controlling the timing of said timing means to enable the operator to vary the conduction angle of said conduction means by varying the location of touch on said touch element; said timing circuit including a resistor; and said touch element comprising a capacitor having one of its plates connected to said resistor and another of its plates exposed for touch by the operator of the control.

Claim 12

In combination with a load adapted to be energized from a source of alternating current, a touch or proximity control for energizing the load, said control comprising a touch element for manual engagement by an operator; solid-state bidirectional controllable conduction means connected between said load and the alternating current source, said controllable conduction means including a control terminal; circuit means including a timing circuit to deliver a voltage of a first polarity to the control terminal a predetermined time after the beginning of each positive half cycle of the alternating current and a voltage of a second polarity to the control terminal a predetermined time after the beginning of each negative half cycle of the alternating current to render said conduction means conductive during each positive and negative half cycle of the alternating current so long as the operator maintains manual engagement with said touch element, said circuit means comprising first solid-state control means connected between said control terminal and said alternating current source and operable, when conductive, to deliver said first polarity voltage, second solid-state control means connected between said control terminal and said alternating current source and operable when conductive to deliver said second polarity voltage, and control circuit means responsive to manual engagement of said touch element to render said first control means conductive during half cycles of said source of a first polarity, and to render said second control means conductive during half cycles of the other polarity; said touch element comprising impedance means, the impedance of which varies with the position thereon of the operator''s touch, said touch element impedance means controlling the timing of said timing means to enable the operator to vary the conduction angle of said conduction means by varying the location of touch on said touch element; said timing circuit including a resistor; and said touch element comprising a capacitor having one of its plates connected to said resistor and another of its plates exposed for touch by the operator of the control.

Claim 13

A touch control according to claim 10 wherein the exposed plate of the capacitor presents a generally triangular surface for touch by the operator.

Claim 14

In combination with a load adapted to be energized from a source of alternating current, a touch or proximity control for energizing the load, said control comprising a touch element for manual engagement by an operator; solid-state bidirectional controllable conduction means connected between said load and the alternating currEnt source, said controllable conduction means including a control terminal; circuit means including a timing circuit to deliver a voltage of a first polarity to the control terminal a predetermined time after the beginning of each positive half cycle of the alternating current and a voltage of a second polarity to the control terminal a predetermined time after the beginning of each negative half cycle of the alternating current to render said conduction means conductive during each positive and negative half cycle of the alternating current so long as the operator maintains manual engagement with said touch element, said circuit means comprising first solid-state control means connected between said control terminal and said alternating current source and operable, when conductive, to deliver said first polarity voltage, second solid-state control means connected between said control terminal and said alternating current source and operable when conductive to deliver said second polarity voltage, and control circuit means responsive to manual engagement of said touch element to render said first control means conductive during half cycles of said source of a first polarity, and to render said second control means conductive during half cycles of the other polarity; said touch element comprising impedance means, the impedance of which varies with the position thereon of the operator''s touch, said touch element impedance means controlling the timing of said timing means to enable the operator to vary the conduction angle of said conduction means by varying the location of touch on said touch element; said timing circuit includes reactance means; said touch element is a resistor having an exposed resistive surface, the impedance of which varies with the location of the operator''s touch thereon; and means connecting said touch element to said reactance means.

Claim 15

In combination with a load adapted to be energized from a source of alternating current, a touch or proximity control for energizing the load, said control comprising a touch element for manual engagement by an operator; solid-state bidirectional controllable conduction means connected between said load and the alternating currEnt source, said controllable conduction means including a control terminal; circuit means including a timing circuit to deliver a voltage of a first polarity to the control terminal a predetermined time after the beginning of each positive half cycle of the alternating current and a voltage of a second polarity to the control terminal a predetermined time after the beginning of each negative half cycle of the alternating current to render said conduction means conductive during each positive and negative half cycle of the alternating current so long as the operator maintains manual engagement with said touch element, said circuit means comprising first solid-state control means connected between said control terminal and said alternating current source and operable, when conductive, to deliver said first polarity voltage, second solid-state control means connected between said control terminal and said alternating current source and operable when conductive to deliver said second polarity voltage, and control circuit means responsive to manual engagement of said touch element to render said first control means conductive during half cycles of said source of a first polarity, and to render said second control means conductive during half cycles of the other polarity; said touch element comprising impedance means, the impedance of which varies with the position thereon of the operator''s touch, said touch element impedance means controlling the timing of said timing means to enable the operator to vary the conduction angle of said conduction means by varying the location of touch on said touch element; said timing circuit includes reactance means; said touch element is a resistor having an exposed resistive surface, the impedance of which varies with the location of the operator''s touch thereon; and means connecting said touch element to said reactance means.

Claim 16

In combination with a portable power tool or appliance including an electrical load adapted to be energized from a source of alternating current, a variable touch control without moving parts for energizing the load, said control comprising solid-state controllable conduction means connected between the load and the alternating current source, said conduction means including a control terminal and being of the type which is rendered conducting by the application of a voltage to said control terminal; control circuit means operably connected between said terminal and said alternating current source to provide a voltage to render said controllable conduction means conduction during half cycles of said alternating current source of at least one polarity; and timing circuit means to controllably vary the time of occurrence of said voltage at said control terminal to vary the conduction angle of the controllable conduction means during at least said half cycles of said one polarity, said means comprising a first impedance having a first end connected to one side of said source of alternating current, and having a second end, and a second impedance connected to said second end of said first impedance and having a fixed surface the impedance of which varies with the location of the operator''s touch thereon, whereby, the impedance of, and correspondingly, the timing of said timing circuit means and the extent of energization of said load can be controllably varied by varying the position of the operator''s finger on said fixed surface.

Claim 17

In combination with a portable power tool or appliance including an electrical load adapted to be energized from a source of alternating current, a variable touch control without moving parts for energizing the load, said control comprising solid-state controllable conduction means connected between the load and the alternating current source, said conduction means including a control terminal and being of the type which is rendered conducting by the application of a voltage to said control terminal; control circuit means operably connected between said terminal and said alternating current source to provide a voltage to render said controllable conduction means conduction during half cycles of said alternating current source of at least one polarity; and timing circuit means to controllably vary the time of occurrence of said voltage at said control terminal to vary the conduction angle of the controllable conduction means during at least said half cycles of said one polarity, said means comprising a first impedance having a first end connected to one side of said source of alternating current, and having a second end, and a second impedance connected to said second end of said first impedance and having a fixed surface the impedance of which varies with the location of the operator''s touch thereon, whereby, the impedance of, and correspondingly, the timing of said timing circuit means and the extent of energization of said load can be controllably varied by varying the position of the operator''s finger on said fixed surface.

Claim 18

The combination of claim 13 wherein said fixed surface of said second impedance is of generally triangular configuration.

Claim 19

The combination of claim 14 wherein a shield normally covers said fixed surface to prevent accidental engagement of said surface by the operator.

Claim 20

The combination of claim 14 wherein said second impedance is a resistor, and said fixed surface includes resistive material.

Claim 21

The combination of claim 14 wherein said second iMpedance is a capacitor, and said fixed surface includes one of the plates of the capacitor.

Claim 22

The combination of claim 13 wherein said first impedance element is a capacitor; and said second impedance element is a resistor.

Claim 23

A control circuit without moving parts for controlling the energization of a load comprising, in combination a solid-state controllable conduction device adapted to be connected in series with the load and having a control terminal; means for connecting said control circuit to an alternating current source; timing circuit means connected to said control terminal to provide a trigger signal thereto during alternating current half cycles of at least one polarity; control means to vary the time of occurrence of said trigger signal during said alternating current half cycles in response to the location of touch of an operator on a touch portion thereof, said control means comprising a resistor in series with said timing circuit means and having a touch surface the resistivity of which varies with the location of the operator''s touch thereon; whereby, the extent of energization of the load can be controlled by the location of the operator''s touch on said touch surface.

Claim 24

A control circuit without moving parts for controlling the energization of a load comprising, in combination a solid-state controllable conduction device adapted to be connected in series with the load and having a control terminal; means for connecting said control circuit to an alternating current source; timing circuit means connected to said control terminal to provide a trigger signal thereto during alternating current half cycles of at least one polarity; control means to vary the time of occurrence of said trigger signal during said alternating current half cycles in response to the location of touch of an operator on a touch portion thereof, said control means comprising a resistor in series with said timing circuit means and having a touch surface the resistivity of which varies with the location of the operator''s touch thereon; whereby, the extent of energization of the load can be controlled by the location of the operator''s touch on said touch surface.

Claim 25

A control circuit without moving parts for controlling the energization of a load comprising, in combination a solid-state controllable conduction device adapted to be connected in series with the load and having a control terminal; means for connecting said control circuit to an alternating current source; timing circuit means connected to said control terminal to provide a trigger signal thereto during alternating current half cycles of at least one polarity; control means to vary the time of occurrence of said trigger signal during said alternating current half cycles in response to the location of touch of an operator on a touch portion thereof, said control means comprising a capacitor in series with said timing circuit means and having a surface the resistivity of which varies with the location of the operator''s touch thereon, whereby, the extent of energization of the load can be controlled by the location of the operator''s touch on said surface.

Claim 26

A control circuit without moving parts for controlling the energization of a load comprising, in combination a solid-state controllable conduction device adapted to be connected in series with the load and having a control terminal; means for connecting said control circuit to an alternating current source; timing circuit means connected to said control terminal to provide a trigger signal thereto during alternating current half cycles of at least one polarity; control means to vary the time of occurrence of said trigger signal during said alternating current half cycles in response to the location of touch of an operator on a touch portion thereof, said control means comprising a capacitor in series with said timing circuit means and having a surface the resistivity of which varies with the location of the operator''s touch thereon, whereby, the extent of energization of the load can be controlled by the location of the operator''s touch on said surface.

Claim 27

A control circuit according to claim 20 wherein said control means further comprises a plurality of capacitors connected to said timing circuit means, each of said capacitors having a touch surface, said touch surfaces providing said touch portion of the control means.

Claim 28

A control circuit without moving parts for controlling the energization of a load comprising, in combination a solid-state controllable conduction device adapted to be connected in series with the load and having a control terminal; means for connecting said control circuit to an alternating current source; timing circuit means connected to said control terminal to provide a trigger signal thereto during alternating current half cycles of at least one polarity; control means to vary the time of occurrence of said trigger signal during said alternating current half cycles in response to the location of touch of an operator on a touch portion thereof, said control means comprising a plurality of resistors connected to said timing circuit means, a plurality of touch means connected respectively to said resistors, and insulated from each other; said plurality of touch means forming the touch portion of said control means; whereby, the extent of energization of the load can be controlled by the location of the operator''s touch on said touch portion.

Claim 29

A control circuit without moving parts for controlling the energization of a load comprising, in combination a solid-state controllable conduction device adapted to be connected in series with the load and having a control terminal; means for connecting said control circuit to an alternating current source; timing circuit means connected to said control terminal to provide a trigger signal thereto during alternating current half cycles of at least one polarity; control means to vary the time of occurrence of said trigger signal during said alternating current half cycles in response to the location of touch of an operator on a touch portion thereof, said control means comprising a plurality of resistors connected to said timing circuit means, a plurality of touch means connected respectively to said resistors, and insulated from each other; said plurality of touch means forming the touch portion of said control means; whereby, the extent of energization of the load can be controlled by the location of the operator''s touch on said touch portion.