Patent ID: 8011547
Filing Date: 2011-09-06
Classification: B25C

Abstract:
1. A driving mechanism for use in a fastener driving tool, said driving mechanism comprising: (a) a hollow cylinder comprising a cylindrical wall and 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; (b) a main storage chamber that is in fluidic communication with said displacement volume of the cylinder, wherein said main storage chamber and said displacement volume are initially charged with a pressurized gas; (c) 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; (d) an elongated driver member that is in mechanical communication with said piston at a third end of said driver member: (e) a lifter member that exhibits a discontinuous contact surface that, at predetermined locations along said discontinuous contact surface, makes contact with said at least one 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 in a second direction from its driven position toward its ready position; (f) a latch member that has a catching surface and a sliding surface, wherein: (g) a one-way mechanism that maintains said lifter in a predetermined position such that the driver member is held at said ready position without said catching surface of the latch member engaging said driver member, and therefore, said latch member is not under mechanical load when said driver member is at said ready position; wherein said cylinder and piston act as a gas spring, under second predetermined conditions, to move said driver member from its ready position toward its driven position, using said pressurized gas of both said main storage chamber and said displacement volume acting on said piston, while said driver member's fourth end contacts said fastener and moves the fastener from said exit end of said guide body.