Trigger mechanism for a power tool

Claim 2

In a power tool having an electrically energizable drive controlled by a switch and accommodated in a housing, a combination comprising a trigger connected with the switch and mounted on the housing for displacement with respect thereto between a deenergizing position in which the switch is open and an energizing position in whicH the switch is closed whereby the drive is energized; biasing means urging said trigger toward said deenergizing position; a latch member mounted on said trigger to share the displacement thereof and also for movement with respect to said trigger between a first, a second, and a third position; and means on the housing operative for engaging said latch member when the same is in said first position so as to prevent displacement of said trigger toward said energizing position, for disengaging said latch member when the same is in said second position so as to permit displacement of said trigger against the force of said biasing means toward said energizing position, and for reengaging said latch member when the same is subsequently moved to said third position while said trigger is in said energizing position whereby to lock said trigger in said energizing position.

Claim 3

A combination as defined in claim 1, wherein said trigger is an elongated lever supported in the housing for pivotal movement.

Claim 4

A combination as defined in claim 2, wherein said biasing means is a spring acting on said trigger so as to pivotally displace the same toward said deenergizing position.

Claim 5

A combination as defined in claim 1, said means comprising a catch affixed to the housing and having a projecting portion; and wherein said latch member comprises a stop located opposite said projecting portion when said latch member is in said first position, and is further provided with a recess adapted to accept said projecting portion subsequently to the displacement of said latch member into said second position and of said trigger into said energizing position.

Claim 6

In a power tool having a housing including a handle and an electrically energizable drive controlled by a switch, a combination comprising a trigger movable in a first direction between a first position in which the switch is open and a second position in which the switch is closed whereby the drive is energized, said trigger being formed with a guide means comprising a first and a second abutment; biasing means urging said trigger toward said first position; a latch member supported by said guide means of said trigger for movement with respect thereto in a second direction substantially normal to said first direction between a latch position in which said latch member prevents said trigger from being displaced, a working position in which said latch member registers with said first abutment and permits displacement of said trigger into said second position in response to a pressure exerted upon said trigger, and permits the return of said trigger into said first position under the urging of said biasing means subsequently to relief of the pressure upon said trigger, and a locking position in which the latch member registers with said second abutment and subsequently to the displacement of said trigger in said second position; and means for retaining said trigger in said second position while said latch is in said locking position.

Claim 7

In a power tool having a housing including a handle and an electrically energizable drive controlled by a switch, a combination comprising a trigger movable in a first direction between a first position in which the switch is open and a second position in which the switch is closed whereby the drive is energized, said trigger being formed with a guide means comprising a first and a second abutment; biasing means urging said trigger toward said first position; a latch member supported by said guide means of said trigger for movement with respect thereto in a second direction substantially normal to said first direction between a latch position in which said latch member prevents said trigger from being displaced, a working position in which said latch member registers with said first abutment and permits displacement of said trigger into said second position in response to a pressure exerted upon said trigger, and permits the return of said trigger into said first position under the urging of said biasing means subsequently to relief of the pressure upon said trigger, and a locking position in which the latch member registers with said second abutment and subsequently to the displacement of said trigger in said second position; and means for retaining said trigger in said second position while said latch is in said locking position.

Claim 8

In a power tool having a housing including a handle and an electrically energizable drive controlled by a switch, a combination comprising a trigger in a first direction between a first position in which the switch is open and a second position in which the switch is closed whereby the drive is energized; biasing means urging said trigger toward said first position; a latch member supported by said trigger for movement with respect thereto in a second direction substantially normal to said first direction and between a latching position in which said latch member prevents said trigger from being displaced, a working position in which said latch member permits displacement of said trigger into said second position in response to a pressure exerted upon said trigger, and permits the return of said trigger into said first position under the urging of said biasing means subsequently to relief of the pressure upon said trigger; and additional biasing means urging said latch member toward said latchiNg position thereof.

Claim 9

In a power tool having a housing including a handle and an electrically energizable drive controlled by a switch, a combination comprising a trigger in a first direction between a first position in which the switch is open and a second position in which the switch is closed whereby the drive is energized; biasing means urging said trigger toward said first position; a latch member supported by said trigger for movement with respect thereto in a second direction substantially normal to said first direction and between a latching position in which said latch member prevents said trigger from being displaced, a working position in which said latch member permits displacement of said trigger into said second position in response to a pressure exerted upon said trigger, and permits the return of said trigger into said first position under the urging of said biasing means subsequently to relief of the pressure upon said trigger; and additional biasing means urging said latch member toward said latchiNg position thereof.

Claim 10

A combination as defined in claim 6, wherein said biasing means is a spring accommodated in said latch member and abutting against a portion of said trigger.

Claim 11

A combination as defined in claim 7, comprising an additional spring attached to said portion of said trigger and abutting against said latch member subsequently to movement thereof beyond said working position toward said locking position.

Claim 12

In a power tool having a housing including a handle and an electrically energizable drive controlled by a switch, a combination comprising a trigger formed as an elongated lever supported in the handle of the power tool for pivotal movement in a first direction between a first position in which the switch is open and a second position in which the switch is closed whereby the drive is energized; biasing means urging said trigger toward said first position; a latch member supported by said trigger for movement with respect thereto in a second direction substantially normal to said first direction and substantially coinciding with the longitudinal direction of said trigger between a latching position in which said latch member prevents said trigger from being displaced, a working position in which siad latch member permits displacement of said trigger into said second position in response to a pressure exerted upon said trigger, and permits the return of said trigger into said first position under the urging of said biasing means subsequently to relief of the pressure upon said trigger and a locking position subsequently to the displacement of said trigger into said second position; and means for retaining said trigger in said second position while said latch member is in said locking position, and comprising a catch affixed to the handle of the power tool and having a projecting portion, and a projection provided on said latch member and engaging said projecting portion when said latch member is in said locking position.

Claim 13

In a power tool having a housing including a handle and an electrically energizable drive controlled by a switch, a combination comprising a trigger formed as an elongated lever supported in the handle of the power tool for pivotal movement in a first direction between a first position in which the switch is open and a second position in which the switch is closed whereby the drive is energized; biasing means urging said trigger toward said first position; a latch member supported by said trigger for movement with respect thereto in a second direction substantially normal to said first direction and substantially coinciding with the longitudinal direction of said trigger between a latching position in which said latch member prevents said trigger from being displaced, a working position in which siad latch member permits displacement of said trigger into said second position in response to a pressure exerted upon said trigger, and permits the return of said trigger into said first position under the urging of said biasing means subsequently to relief of the pressure upon said trigger and a locking position subsequently to the displacement of said trigger into said second position; and means for retaining said trigger in said second position while said latch member is in said locking position, and comprising a catch affixed to the handle of the power tool and having a projecting portion, and a projection provided on said latch member and engaging said projecting portion when said latch member is in said locking position.

Claim 14

A combination as defined in claim 9, further comprising additional biasing means urging said latch member toward said working position and said latching position; and wherein the engagement between said projection of said latch member and said projecting portion of said catch is due to a friction force between the former and the latter, said friction force exceeding a biasing force exerted by said additional biasing means.

Claim 15

A combination as defined in claim 10, wherein said projecting portion is provided with an angular end portion, said latch member is provided with a recess adapted to accommodate said projecting portion subsequently to displacement of said latch member into said working position and of said trigger into said second position and between said working position and said locking position of said latching member; and wherein said projection extends into said recess so as to engage said angular end portion of said catch.

Claim 16

A combination as defined in claim 11, wherein said catch is an angular strip member.