Butt-contact speed control trigger switch

Claim 2

A self-enclosed double-pole trigger switch comprising: a switch operating trigger including a return spring normally biasing said trigger into its off position from which it can be actuated to its on position by the fore-finger of the user; a switch housing comprising: an insulating base; a frame mounting said trigger for movement along the top of said base; a pair of open-top compartments in said housing under-lying said trigger; butt contact means in said compartments, said butt contact means comprising: first stationary contacts mounted on said base within the corresponding compartments and each having an electrical connector for connecting said stationary contact to an external circuit; movable butt contacts guided by the walls of their compartments for tiltable movement in vertical planes; and a pressure spring at the center of each said movable butt contact biasing one end of said movable butt contact toward engagement with said stationary contact to provide the required contact pressure when the contacts are closed; and means providing electrical connections from said movable butt contacts to said external circuit comprising: a pair of connectors continuously in engagement with the respective movable butt contacts; one of said butt contact means further comprising: a second stationary contact mounted on said base within the corresponding compartment for engagement by the other end of the associated movable butt contact under the force of its pressure spring and having an electrical connector for connecting said second stationary contact to said external circuit; and cooperating cam and cam follower means on said movable butt contacts and on said trigger for tilting said movable butt contacts away from said stationary contacts when said trigger is released to its off position and for allowing said pressure springs to tilt first ends of the movable butt contacts closed to said first stationary contacts on predetermined movement of said trigger when actuated to said on position and to tilt the other end of one of said movable butt contacts closed to said second stationary contact on further movement of said trigger.

Claim 3

The invention defined in claim 1, wherein said cooperating means comprises: a laterally offset cam follower on each movable butt contact extending from its open-top compartment into the path of the trigger above said base; and a cam on said trigger for each said cam follower for engaging said cam follower to tilt said movable butt contact against the force of said pressure spring in response to trigger actuation.

Claim 4

The invention defined in claim 1, wherein: said insulating base comprises a pair of cavities, one on each side thereof; and said frame comprises a skirt surrounding said base and embracing said cavities to form said open top compartments in which said butt contacts means are mounted.

Claim 5

The invention defined in claim 1, wherein said electrical connectors together with said pair of connectors comprise: a pair of load terminal connectors across which a load device may be connected and a pair of line terminal connectors for connecting said switch across an electrical power source whereby the double-pole switch affords connection and disconnection of both sides of the power source to the load.

Claim 6

A self-enclosed double-poLe speed control trigger switch comprising: a return spring biased trigger adapted for operation by the forefinger of the user; a frame mounting said trigger for movement therein and having a base-embracing portion; a switch base comprising a pair of insulating base halves held fixed within said base-embracing portion of said frame with their tops abutting said trigger and defining with said frame left and right, open-top, switch compartments, respectively; said insulating base halves defining therebetween a central compartment separated from said left and right compartments; switch means comprising a double-pole butt contact on-off switch having one pole thereof in each of said left and right compartments; each said switch pole comprising a pair of stationary contact-connector members mounted in spaced slots in the respective base half within the associated compartment, and a movable butt contact including a central bias spring biasing opposite ends of said butt contact into closure with said stationary contact-connector members, and a pair of laterally offset cam followers on said movable butt contact extending up through the open top of the associated compartment into the path of said trigger; cams on said trigger engaging predetermined cam followers of the two movable butt contacts of said double-pole switch to afford tiltable closing and opening of one or both ends of said movable butt contacts with respect to said stationary contact-connector members when said trigger is operated; a thyristor speed control circuit mounted in said central compartment and comprising a variable resistor having its resistor strip mounted at the upper portion of said central compartment and a movable brush contact mounted in a slot in said trigger and movable therewith to vary the amount of resistance in said speed control circuit, and means adapting said speed control circuit and a motor for connection to and disconnection from an electrical power source by the two poles of said double-pole switch.

Claim 7

A self-enclosed double-poLe speed control trigger switch comprising: a return spring biased trigger adapted for operation by the forefinger of the user; a frame mounting said trigger for movement therein and having a base-embracing portion; a switch base comprising a pair of insulating base halves held fixed within said base-embracing portion of said frame with their tops abutting said trigger and defining with said frame left and right, open-top, switch compartments, respectively; said insulating base halves defining therebetween a central compartment separated from said left and right compartments; switch means comprising a double-pole butt contact on-off switch having one pole thereof in each of said left and right compartments; each said switch pole comprising a pair of stationary contact-connector members mounted in spaced slots in the respective base half within the associated compartment, and a movable butt contact including a central bias spring biasing opposite ends of said butt contact into closure with said stationary contact-connector members, and a pair of laterally offset cam followers on said movable butt contact extending up through the open top of the associated compartment into the path of said trigger; cams on said trigger engaging predetermined cam followers of the two movable butt contacts of said double-pole switch to afford tiltable closing and opening of one or both ends of said movable butt contacts with respect to said stationary contact-connector members when said trigger is operated; a thyristor speed control circuit mounted in said central compartment and comprising a variable resistor having its resistor strip mounted at the upper portion of said central compartment and a movable brush contact mounted in a slot in said trigger and movable therewith to vary the amount of resistance in said speed control circuit, and means adapting said speed control circuit and a motor for connection to and disconnection from an electrical power source by the two poles of said double-pole switch.

Claim 8

The invention defined in claim 5, wherein said switch means comprises a shunting switch comprising: one of the stationary contact-connector members of one of said pairs thereof mounted in a slot in one of said switch compartments; one of the laterally offset cam followers on the associated movable butt contact extending up from the open top of the associated switch compartment into the path of said trigger; one of the cams on said trigger spaced from the other cams to afford tiltable closure of said shunting switch near the end of the trigger stroke; and means connecting said shunting switch to shunt said speed control circuit.

Claim 9

The invention defined in claim 6, wherein said thyristor speed control circuit comprises: a thyristor triode having main conduction terminals and a gate; a triggering device connected to said gate; a heat sink to which said thyristor triode is mounted by connecting one main conduction terminal thereto; a firing capacitor in said central compartment; a connector having spring pressure engagement with said resistor strip, and leads from said capacitor and triggering device having welded connections to said connector; a tab on said shunting switch stationary contact connector member extending into said central compartment and leads from said capacitor and the other main conduction terminal of said thyristor triode being welded thereto; and spring pressure means connecting the movable butt contact associated with said shunting switch to said heat sink.

Claim 10

A self-enclosed double-pole speed control trigger switch comprising: a return spring biased trigger adapted for operation by the forefinger of the user; a frame mounting said trigger for movement therein and having a base-embracing portion; a switch base comprising a pair of insulating base halves held fixed within said base-embracing portion of said frame with their tops abutting said trigger and defiNing with said frame left and right, open-top, switch compartments, respectively; said insulating base halves defining therebetween a central compartment separated from said left and right compartments; switch means comprising a double-pole butt contact on-off switch having one pole thereof in each of said left and right compartments; each said switch pole comprising a stationary contact including a wire connector portion mounted in a slot in the respective base half within the associated compartment, and a movable butt contact including a bias spring biasing said butt contact into closure with said stationary contact, and a cam follower on said movable butt contact extending up through the open top of the associated compartment into the path of said trigger; cams on said trigger engaging the cam followers of the two poles of said double-pole switch to afford closing and opening of said contacts when said trigger is operated; a thyristor speed control circuit mounted in said central compartment and comprising a variable resistor having its resistor strip mounted at the upper portion of said central compartment and a movable brush contact mounted in a slot in said trigger and movable therewith to vary the amount of resistance in said speed control circuit; at least one of said base halves comprising a pair of abutments limiting rubbing movement of the movable butt contact on the associated stationary contact to afford limited cleaning movement therebetween; a resilient drive member mounted on said trigger to engage said cam follower following closure of the associated contacts to slide said movable butt contact on the associated stationary contact for cleaning motion at the extreme end of the trigger stroke; and the associated cam on said trigger being effective on return movement of the trigger to slide said movable butt contact on said associated stationary contact in the reverse direction for additional cleaning motion.

Claim 11

A self-enclosed double-pole speed control trigger switch comprising: a return spring biased trigger adapted for operation by the forefinger of the user; a frame mounting said trigger for movement therein and having a base-embracing portion; a switch base comprising a pair of insulating base halves held fixed within said base-embracing portion of said frame with their tops abutting said trigger and defiNing with said frame left and right, open-top, switch compartments, respectively; said insulating base halves defining therebetween a central compartment separated from said left and right compartments; switch means comprising a double-pole butt contact on-off switch having one pole thereof in each of said left and right compartments; each said switch pole comprising a stationary contact including a wire connector portion mounted in a slot in the respective base half within the associated compartment, and a movable butt contact including a bias spring biasing said butt contact into closure with said stationary contact, and a cam follower on said movable butt contact extending up through the open top of the associated compartment into the path of said trigger; cams on said trigger engaging the cam followers of the two poles of said double-pole switch to afford closing and opening of said contacts when said trigger is operated; a thyristor speed control circuit mounted in said central compartment and comprising a variable resistor having its resistor strip mounted at the upper portion of said central compartment and a movable brush contact mounted in a slot in said trigger and movable therewith to vary the amount of resistance in said speed control circuit; at least one of said base halves comprising a pair of abutments limiting rubbing movement of the movable butt contact on the associated stationary contact to afford limited cleaning movement therebetween; a resilient drive member mounted on said trigger to engage said cam follower following closure of the associated contacts to slide said movable butt contact on the associated stationary contact for cleaning motion at the extreme end of the trigger stroke; and the associated cam on said trigger being effective on return movement of the trigger to slide said movable butt contact on said associated stationary contact in the reverse direction for additional cleaning motion.

Claim 12

The invention defined in claim 8, wherein: one of said cams on said trigger is provided with a position and angle so as to cause closing of its associated switch pole before than and reopening after the other switch pole so that said other switch pole which is provided with said resilient drive member takes up all the contact arcing.

Claim 13

The invention defined in claim 5, wherein: one of said base halves comprises a ledge within the upper portion of said central compartment to provide a shallow channel at the top of said base separated from said left and right compartments; said resistor strip mounted flat on said ledge for engagement by said movable brush contact.

Claim 14

A self-enclosed speed control trigger switch comprising: a return spring biased trigger adapted for operation by the forefinger of the user; a frame mounting said trigger for movement therein and having a base-embracing portion; a switch base comprising a pair of insulating base halves held fixed within said base-embracing portion of said frame with their tops abutting said trigger and defining with said frame left and right, open-top, switch compartments, respectively; said insulating base halves defining therebetween a central compartment separated from said left and right compartments; switch means comprising a double-pole butt contact on-off switch having one pole thereof in each of said left and right compartments; each said switch pole comprising a stationary contact including a wire connector mounted in a slot in the respective base half within the associated compartment, and a movable butt contact including a bias spring biasing said butt contact into closure with said stationary contact, and a cam follower on said movable butt contact extending up through the open top of the associated comaprtment into the path of said trigger; cams on said trigger engaging the cam followers of the two poles of said double-pole switch to afford closing and opening of said contacts when said triGger is operated; a thyristor speed control circuit mounted in said central compartment and comprising a variable resistor having its resistor strip mounted at the upper portion of said central compartment and a movable brush contact mounted in a slot in said trigger and movable therewith to vary the amount of resistance in said speed control circuit; each said stationary contact of the double-pole switch being mounted at one end of the associated compartment, and the respective connector portions of these two stationary contacts being arranged for connections in the two sides of an alternating current circuit connecting power through said speed control circuit to a motor; a shunting contact consisting of a third like stationary contact including a wire connector portion mounted in a slot in the other end of one of said switch compartments and means connecting the shunting switch formed by said third stationary contact and the associated movable butt contact across said speed control circuit; a connector member consisting of a fourth member similar to said stationary contacts including a wire connector portion mounted in a slot in the other end of the other one of said switch compartments and arranged for connecting the associated movable butt contact in said A.C. circuit; and each said movable butt contact comprising an elongated member biased at its center and having a second cam follower thereon; one of said movable butt contacts being electrically connected to said speed control circuit and being operable to engage at one end thereof the stationary contact of one pole of said switch on initial operation of said trigger to connect said speed control circuit to said power, and to additionally engage the stationary contact of said shunting switch at the other end thereof by action of said second cam follower and said third cam on further operation of said trigger to by-pass said speed control circuit; the other movable butt contact being operable to engage the stationary contact of the other pole of said switch at one end thereof on initial operation on said trigger while remaining constantly in engagement with said connector member at the other end thereof.

Claim 15

A self-enclosed speed control trigger switch comprising: a return spring biased trigger adapted for operation by the forefinger of the user; a frame mounting said trigger for movement therein and having a base-embracing portion; a switch base comprising a pair of insulating base halves held fixed within said base-embracing portion of said frame with their tops abutting said trigger and defining with said frame left and right, open-top, switch compartments, respectively; said insulating base halves defining therebetween a central compartment separated from said left and right compartments; switch means comprising a double-pole butt contact on-off switch having one pole thereof in each of said left and right compartments; each said switch pole comprising a stationary contact including a wire connector mounted in a slot in the respective base half within the associated compartment, and a movable butt contact including a bias spring biasing said butt contact into closure with said stationary contact, and a cam follower on said movable butt contact extending up through the open top of the associated comaprtment into the path of said trigger; cams on said trigger engaging the cam followers of the two poles of said double-pole switch to afford closing and opening of said contacts when said triGger is operated; a thyristor speed control circuit mounted in said central compartment and comprising a variable resistor having its resistor strip mounted at the upper portion of said central compartment and a movable brush contact mounted in a slot in said trigger and movable therewith to vary the amount of resistance in said speed control circuit; each said stationary contact of the double-pole switch being mounted at one end of the associated compartment, and the respective connector portions of these two stationary contacts being arranged for connections in the two sides of an alternating current circuit connecting power through said speed control circuit to a motor; a shunting contact consisting of a third like stationary contact including a wire connector portion mounted in a slot in the other end of one of said switch compartments and means connecting the shunting switch formed by said third stationary contact and the associated movable butt contact across said speed control circuit; a connector member consisting of a fourth member similar to said stationary contacts including a wire connector portion mounted in a slot in the other end of the other one of said switch compartments and arranged for connecting the associated movable butt contact in said A.C. circuit; and each said movable butt contact comprising an elongated member biased at its center and having a second cam follower thereon; one of said movable butt contacts being electrically connected to said speed control circuit and being operable to engage at one end thereof the stationary contact of one pole of said switch on initial operation of said trigger to connect said speed control circuit to said power, and to additionally engage the stationary contact of said shunting switch at the other end thereof by action of said second cam follower and said third cam on further operation of said trigger to by-pass said speed control circuit; the other movable butt contact being operable to engage the stationary contact of the other pole of said switch at one end thereof on initial operation on said trigger while remaining constantly in engagement with said connector member at the other end thereof.

Claim 16

The invention defined in claim 11, wherein: said double-pole switch may readily be converted to a single-pole switch by omitting in assembly the stationary contact, connector member, movable butt contact and its bias spring from the corresponding switch compartment and instead connecting the corresponding side of the load and power line directly together.

Claim 17

The invention defined in claim 5, wherein: the wire connector portions of the two poles of said double-pole switch are adapted to be connected to the two sides of an alternating current power source; and said switch comprises means for connecting said speed control circuit in series with a load between the two poles of said double-pole switch so that said speed control circuit is completely disconnected from the power source when said switch is off.