US 8,011,547 B2 · Fastener driving tool using a gas spring

Abstract

A portable linear fastener driving tool is provided that drive staples, nails, or other linearly driven fasteners. The tool uses a gas spring principle, in which a cylinder filled with compressed gas is used to quickly force a piston through a driving stroke movement, while a driver also drives a fastener into a workpiece. The piston/driver is then moved back to its starting position by use of a rotary-to-linear lifter, and the piston again compresses the gas above the piston, thereby preparing the tool for another driving stroke. The driver has protrusions along its edges that contact the lifter, which lifts the driver during a return stroke. A pivotable latch is controlled to move into either an interfering position or a non-interfering position with respect to the driver protrusions, and acts as a safety device, by preventing the driver from making a full driving stroke at an improper time.

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:
(i) said driver member having a fourth, opposite end that is sized and shaped to push a fastener from said exit end of the guide body, wherein said passageway of the guide body allows said driver member to pass therethrough toward said exit end during a driving stroke and toward said receiving end during a return stroke, said driver member, when at a driven position, protruding toward said exit end of the guide body after said piston moves toward the second end of said cylinder, and said driver member, when at a ready position, being withdrawn into said guide body after said piston moves toward the first end of said cylinder,
(ii) said driver member having at least one longitudinal edge that is substantially parallel to a direction of movement of said driver member between its driven and ready positions,
(iii) said driver member having at least one plurality of spaced-apart protrusions along said at least one longitudinal edge;
(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:
(i) under third predetermined conditions, said latch member is controlled by a separate device and is forced into a non-catching position such that its catching surface does not interfere with said at least one plurality of spaced-apart protrusions of said driver member, thereby allowing said driver member to move in a third direction from its ready position to its driven position;
and
(ii) under fourth predetermined conditions, during which said driver member is being moved in said second direction from its driven position to its ready position, said separate device releases said latch member so that the latch member is not forced into a non-catching position, said latch member is directed toward a catching position, however, said sliding surface of the latch member allows said at least one plurality of spaced-apart protrusions of the driver member to slide along the latch member without being stopped so long as the driver member remains moving in the second direction;
and
(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.

12 more elements

Fastener driving tool using a gas spring

Life of this patent

Fastener driving tool using a gas spring

Life of this patent

Abstract

Claims39