Patent ID: 6419140
Filing Date: 2002-07-16
Classification: B25C

Abstract:
A pneumatic nail-driving gun comprising:a gun body including a handle with a movable valve rod that is biased to a non-compressing position and that is movable to a compressing position, and a horizontal barrel having a rear portion that is attached to said handle, and a front portion with a nail-shooting seat that is adapted to shoot a nail therefrom when said valve rod moves from the non-compressing position to the compressing position; a safety rod disposed movably on a front end of said barrel and having a wall-pressing rod portion that is adapted to abut against a wall, into which the nail is to be driven; a press member connected fixedly to said safety rod and having a rear pressing section with an upwardly extending integral rear projection; a biasing unit for biasing said press member to a front limit position relative to said barrel, said press member being movable relative to said barrel to a rear limit position when said wall-pressing rod portion of said safety rod is pressed forcibly against the wall; and a trigger assembly including a pivot member disposed pivotally on said barrel and having a lower portion and an upper portion which is formed with a guide slot unit that has a closed front end and a closed rear end, a trigger member connected fixedly to said lower portion of said pivot member and biased to a non-actuated position relative to said barrel, said trigger member being rotatable to an actuated position that is located behind the non-actuated position, a horizontal positioning pin received slidably within said guide slot unit in said pivot member and disposed at a rear portion of said slide slot behind said rear projection of said press member when said press member is located at the front limit position and when said trigger member is located at the non-actuated position, a pushing plate disposed pivotally on said trigger member and located in front of said valve rod, said pushing plate having a free end, and a spring for biasing said free end of said pushing plate away from said valve rod to abut against said rear pressing section of said press member, said pushing plate being pushed rearward by said press member and said trigger member against biasing action of said spring, thereby contacting and moving said valve rod to the compressing position when said press member moves to the rear limit position and when said trigger member moves to the actuated position; wherein when said safety rod is first pressed forward against the wall so as to move said press member to the rear limit position and when said trigger member is subsequently pressed rearward to the actuated position for moving said valve rod from the non-compressing position to the compressing position so as to perform a nail shooting operation, said positioning pin moves forward within said guide slot unit in said pivot member to a position adjacent to and in front of said rear projection of said press member so as to prevent forward movement of said rear projection, thereby retaining said press member at the rear limit position to prevent forward movement of said valve rod from the compressing position and thus a subsequent nail shooting operation so as to result in a single shot operation; wherein when said trigger member is first pressed rearward to the actuated position and when said safety rod is subsequently pressed forward against the wall, thereby moving said valve rod so as to perform the nail shooting operation, said rear projection contacts and moves said positioning pin rearward within said guide slot unit to push said pushing plate rearward for moving said valve rod from the non-compressing position to the compressing position so as to perform a nail shooting operation, after which said safety rod can be once again pressed against the wall, thereby permitting movement of said press member from the front limit position to the rear limit position, with said trigger member being maintained at the actuated position, to commence with a subsequent nail shooting operation so as to result in a continuous shooting operation.