Method for controlling a fastener driving tool using a gas spring

CAFC
  • US 8,286,722 B2
  • Filed: 10/27/2010
  • Issued: 10/16/2012
  • Est. Priority Date: 10/05/2007
  • Status: Active Grant
First Claim
Patent Images

1. A fastener driving tool, comprising:

  • (a) a housing that contains a prime mover, and a system controller;

    (b) a fastener driving mechanism that includes;

    (i) a hollow cylinder having a movable piston therewithin, said hollow cylinder having a first end and a second, opposite end, said hollow cylinder containing a displacement volume created by a stroke of said piston, said displacement volume being initially charged with a pressurized gas;

    (ii) a guide body that is substantially adjacent to the second end of said cylinder, said guide body having a receiving end, an exit end, and a passageway therebetween, said receiving end being proximal to said second end of the cylinder, said guide body being configured to receive a fastener that is to be driven from said exit end;

    (iii) an elongated driver member that is in mechanical communication with said piston, said driver member having a driving surface that is sized and shaped to push a fastener into an external workpiece, wherein said passageway of the guide body allows said driver member to pass therethrough toward said exit end during a driving stroke, and allows said driver member to pass therethrough away from said exit end during a lifting interval;

    (A) said driver member having a first longitudinal edge;

    (B) said driver member having a first plurality of spaced-apart protrusions along said first longitudinal edge; and

    (iv) a lifter member that exhibits an outer shape that defines a perimeter of said lifter member'"'"'s surface;

    (A) said lifter member being movable, under command of said system controller, by said prime mover;

    (B) said lifter member having a discontinuous contact surface that, at predetermined locations along said discontinuous contact surface, makes contact with said first plurality of spaced-apart protrusions of said driver member such that, under first predetermined conditions, said lifter member is moved in a first direction and thereby causes said driver member to be moved from its driven position toward its ready position; and

    (C) said lifter member being positionable by said prime mover, under second predetermined conditions, such that said discontinuous contact surface of the lifter member does not mechanically interfere with said first plurality of spaced-apart protrusions along said first longitudinal edge of the driver member during said driving stroke, in which said driver member moves from its ready position toward its driven position;

    (c) a safety contact element that extends to said exit end of the guide body, and which is movable between an actuated position when said safety contact element is pressed against said external workpiece, and a non-actuated position when said safety contact element is not pressed against said external workpiece;

    (d) a trigger actuator that is user-actuated;

    (e) a trigger position sensor; and

    (f) a safety contact element position sensor;

    wherein said cylinder and piston act as a gas spring, under said second predetermined conditions, to move said driver member from its ready position toward its driven position, using said pressurized gas acting on said piston, while said driver member'"'"'s driving surface contacts a fastener and moves the fastener toward said exit end of said guide body.

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