Lock-off switch

Claim 2

A self-enclosed trigger switch for a portable electric tool affording operation of the tool but preventing accidental operation thereof comprising: an insulating base housing the switch mechanism; a movable spring-biased trigger having a normal off position in which the tool is not in operation and having an alternate on position in which the tool is in operation; a frame secured to said base and mounting said trigger for movement relative to said base and frame; means coupling said trigger to the switch mechanism to afford operation thereof; and an automatically-engaging off lock for said trigger comprising: a rigid locking member having a detent at one end portion; a slot in one side of said trigger for accommodating said locking member and including a notch seating the other end of said locking member; said notch being in the forward end of said slot and seating the forward end of said rigid locking member for limited pivotal movement within said slot, and said rigid locking member being confined in said slot by the abutting rear end wall of the latter; a compression spring within sAid trigger biasing said one end of said locking member against the adjacent inner wall of said frame; a hole in said adjacent wall of said frame disposed to receive said detent in the off position of said trigger; and a spring-biased release button mounted on said frame and disposed to release said detent from said hole.

Claim 3

The invention defined in claim 1 wherein said rigid locking member comprises: an elongated strip of steel thick enough and stiff enough to resist bending or flexing on attempted forcing of the trigger.

Claim 4

The invention defined in claim 2, wherein: said notch is offset toward the center line of said trigger from the plane of said adjacent wall of the frame to dispose said locking member at an angle causing tightening of the locking engagement on attempted forcing of the trigger.

Claim 5

A self-enclosed trigger switch for a portable electric tool affording operation of the tool but preventing accidental operation thereof comprising: an insulating base housing the switch mechanism; a movable spring-biased trigger having a normal off position in which the tool is not in operation and having an alternate on position in which the tool is in operation; a frame secured to said base and mounting said trigger for movement relative to said base and frame; means coupling said trigger to the switch mechanism to afford operation thereof; and an automatically-engaging off lock for said trigger comprising: a rigid locking member having a detent at one end; a slot in one side of said trigger for accommodating said locking member and including a notch seating the other end of said locking member; a compression spring within said trigger biasing said one end of said locking member against the adjacent inner wall of said frame; a hole in said adjacent wall of said frame disposed to receive said detent in the off position of said trigger; and a spring-biased release button mounted on said frame and disposed to release said detent from said hole; said rigid locking member comprising an elongated strip of steel thick enough and stiff enough to resist bending or flexing on attempted forcing of the trigger; said detent comprising a steel disc rigidly secured to one surface of said steel strip adjacent the rear end thereof; and said notch is in the forward end of said slot and seats the forward end of said steel strip for limited pivotal movement within said slot.

Claim 6

A self-enclosed trigger switch for a portable electric tool affording operation of the tool but preventing accidental operation thereof comprising: an insulating base housing the switch mechanism; a movable spring-biased trigger having a normal off position in which the tool is not in operation and having an alternate on position in which the tool is in operation; a frame secured to said base and mounting said trigger for movement relative to said base and frame; means coupling said trigger to the switch mechanism to afford operation thereof; and an automatically-engaging off lock for said trigger comprising: a rigid locking member having a detent at one end; a slot in one side of said trigger for accommodating said locking member and including a notch seating the other end of said locking member; a compression spring within said trigger biasing said one end of said locking member against the adjacent inner wall of said frame; a hole in said adjacent wall of said frame disposed to receive said detent in the off position of said trigger; and a spring-biased release button mounted on said frame and disposed to release said detent from said hole; said rigid locking member comprising an elongated strip of steel thick enough and stiff enough to resist bending or flexing on attempted forcing of the trigger; said detent comprising a steel disc rigidly secured to one surface of said steel strip adjacent the rear end thereof; and said notch is in the forward end of said slot and seats the forward end of said steel strip for limited pivotal movement within said slot.

Claim 7

The invention defined in claim 4, wherein: said notch is offset toward the center line of said trigger from the plane of said adjacent wall of the frame to dispose said locking member at an angle causing tightening of the locking engagement on attempted forcing of the trigger.

Claim 8

The invention defined in claim 1, wherein: said trigger comprises an overhanging ledge over said slot for confining said locking member therebelow.

Claim 9

The invention defined in claim 1, wherein: said compression spring is a helical spring having one end against the opposite surface of said locking member adjacent said detent; and said trigger comprises a well in said slot for retaining the other end of said spring.

Claim 10

In combination with a portable tool having a handle to be grasped by the hand of the user, an aperture in the front of the handle for a trigger and a hole in one side of the handle for an off lock release member: a self-enclosed trigger switch mounted within said handle comprising: a housing for the switch mechanism; a trigger mounted on said housing for limited sliding movement between an on position wherein the switch is in operation and an off position wherein the switch is not in operation; said trigger extending out of said aperture for depression by the forefinger of the user; a return spring normally biasing said trigger into its off position; and an automatically engaging off lock for said trigger including: space within said trigger defined by a pivot at the forward end of saId space and an abutment at the rear end thereof; an elongated rigid locking lever within said space seated at its forward end in said pivot and its rear end being confined by said abutment and having a detent at its rear end portion; a catch in said housing for receiving said detent to lock the trigger in its off position; a compression spring between said trigger and said locking lever biasing said detent into said catch; and a spring-biased release member mounted on said housing and disposed to be depressed by the thumb of the user to pivot said locking lever and move said detent clear of said catch to allow depression of said trigger to its on position; and said abutment causing said locking lever to return with the trigger upon release of the latter to enable said compression spring to snap said detent back into said catch to lock said trigger in its off position.

Claim 11

In combination with a portable tool having a handle to be grasped by the hand of the user, an aperture in the front of the handle for a trigger and a hole in one side of the handle for an off lock release member: a self-enclosed trigger switch mounted within said handle comprising: a housing for the switch mechanism; a trigger mounted on said housing for limited sliding movement between an on position wherein the switch is in operation and an off position wherein the switch is not in operation; said trigger extending out of said aperture for depression by the forefinger of the user; a return spring normally biasing said trigger into its off position; and an automatically engaging off lock for said trigger including: space within said trigger defined by a pivot at the forward end of saId space and an abutment at the rear end thereof; an elongated rigid locking lever within said space seated at its forward end in said pivot and its rear end being confined by said abutment and having a detent at its rear end portion; a catch in said housing for receiving said detent to lock the trigger in its off position; a compression spring between said trigger and said locking lever biasing said detent into said catch; and a spring-biased release member mounted on said housing and disposed to be depressed by the thumb of the user to pivot said locking lever and move said detent clear of said catch to allow depression of said trigger to its on position; and said abutment causing said locking lever to return with the trigger upon release of the latter to enable said compression spring to snap said detent back into said catch to lock said trigger in its off position.

Claim 12

The invention defined in claim 8, wherein: said pivot for the forward end of said locking lever is offset toward the center line of said trigger from the plane of said catch to provide an angular line of force insuring engagement of said detent in said catch in the event of attempted forcing of said trigger.

Claim 13

The invention defined in claim 8, wherein said locking lever is disposed in a vertical plane and said detent is a coin-shaped projection on the flat surface thereof.