초록 ▼

A fastener driving device such as a tacker, including an actuating circuit for producing a power stroke for substantially a complete half cycle of an AC potential supply and which occurs a fixed number of cycles following the actuation of a switch actuable at random times with respect to the cycles

A fastener driving device such as a tacker, including an actuating circuit for producing a power stroke for substantially a complete half cycle of an AC potential supply and which occurs a fixed number of cycles following the actuation of a switch actuable at random times with respect to the cycles of the AC supply. The circuit features a decade counter clocked by the AC supply. One of the decade count outputs of the counter provides a signal for firing an SCR in series circuit with a solenoid for powering the tool. The counter is wired in circuit so as to latch at a predetermined count higher than the count output from which the firing signal is taken. Actuating the switch causes the counter to reset to zero, after which it counts positive half-cycles of the AC. When it reaches the count corresponding to the output from which the firing signal is taken, the tool is actuated. The counter continues to count until it relatches. It remains at the latched count until the switch is again actuated. Protection is provided against unintended tool actuation when power is first applied.

대표청구항 ▼

An electrically operated fastener driving device comprising: a housing assembly defining a drive track; a driver movably engaged within said drive track; a magazine for feeding fasteners to said drive track for being driven by said driver; a solenoid energizable to move said driver through a drive s

An electrically operated fastener driving device comprising: a housing assembly defining a drive track; a driver movably engaged within said drive track; a magazine for feeding fasteners to said drive track for being driven by said driver; a solenoid energizable to move said driver through a drive stroke in said drive track; circuit means, including a controlled conduction device having a control electrode, for conducting power from an AC potential source to said solenoid to energize it whenever a firing signal is applied to said control electrode; switch means having a normally “off”position and operable in response to an actuation to move into a “fire”position at a random time relative to the cycles of the AC potential; and counter means for (a) counting the cycles of AC potential occurring after an actuation of said switch means from its normally “off”position to its “fire”position and (b) applying a firing signal to said control electrode to place said controlled conduction means in a conductive state during a properly poled half cycle of said AC potential occurring a predetermined number of cycles greater than one (1) after the actuation of said switch means, the conductive state of said controlled conductive device causing said solenoid to be energized, and (c) preventing the application of a further signal to said control electrode after the application of said firing signal until said switch means is returned to its “off”position and reactuated to its “fire”position.