Patent Publication Number: US-6908021-B1

Title: Safety catch mechanism of nail guns

Description:
FIELD OF THE INVENTION 
   The present invention relates to a nail gun assembly, more particularly to a nail gun assembly with a safety catch mechanism for preventing users from shooting the nail gun without nails. 
   BACKGROUND OF THE INVENTION 
   In general, a prior-art nail gun usually comprises a muzzle disposed at the front end of a nailing device in the main body of the nail gun, a magazine interconnectably disposed at the bottom of the muzzle for accommodating and storing nails. Further, a trigger is disposed on the handle of the main body of the nail gun for controlling the high-pressure airflow inside the nail gun and a firing pin of the nail gun for the shooting. By the shooting force of the firing pin, the nail in the muzzle can be shot into a work piece. 
   However, when users use such prior-art nail gun, the nails are shot continuously without knowing the current quantity of nails in the magazine. Therefore, after the nails in the magazine are exhausted, users may continue to cock the trigger. Some users even cock the trigger for several times intentionally to make sure there is no nail in the magazine before reloading the magazine with nails. As to the structure of the nail gun, shooting by a firing pin or other firing device without nails in the magazine may have adverse effects on the life of the nail gun or even cause damages to the nail gun. 
   SUMMARY OF THE INVENTION 
   The primary objective of the present invention is to provide a safety catch mechanism for preventing users from shooting without nails in the magazine. By means of a blocking plate and a rotary rod, if there is no nail in the magazine, the blocking plate will block the rear of the trigger and prevent the trigger from being cocked. If the magazine is loaded with nails, then the latch can be pushed to drive the push arm to rotate outward, such that the blocking plate is separated from the rear of the trigger, and thus allowing users to cock the trigger. Therefore, the present invention can effectively prevent user from shooting a nail gun without nails in the magazine, and thus preventing the structure of the firing device and firing pin from being damaged or the life of use shortened due to the firing without having nails in the magazine. 
   The technical measures taken by the invention to overcome the aforementioned shortcomings are given below: 
   A safety catch mechanism for preventing a nail gun from shooting without nails in the magazine comprises:
         a main body, having a trigger disposed on a handle of said main body, a muzzle disposed at the front end of the main body, and a magazine interconnectably disposed at the bottom of the muzzle; wherein a through hole is disposed on the upper wall of the magazine and an axle section protruded from one side of the magazine;   a rotary rod, being movably disposed on the axle section, and having a push arm extended from the front end of the rotary rod, an embedding plate being bent from the front end of the push arm, an embedding groove disposed on the embedding plate, a blocking arm extended from the rear of the rotary rod and bent in the direction towards the trigger, and a blocking plate being bent from the rear end of the blocking arm and extended to the rear of the trigger; and   a limit plate, being movably passed into the through hole of the magazine, and one end of the limit plate being movably embedded into the embedding groove of the rotary rod, wherein the limit plate forms a latch protruded from an inner wall of the magazine.       

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view of the safety catch mechanism of the present invention. 
       FIG. 2  is a view of the safety catch mechanism of the present invention. 
       FIG. 3  is another view of the safety catch mechanism of the present invention. 
       FIG. 4  is a view of the movements of the safety catch mechanism of the present invention. 
       FIG. 5  is another view of the movements of the safety catch mechanism of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   To make it easier for our examiner to understand the objective of the invention, its structure, innovative features, and performance, we use a preferred embodiment together with the attached drawings for the detailed description of the invention. 
   Please refer to  FIGS. 1 to 3  for a safety catch mechanism of the present invention, which comprises:
         a main body  10 , having a trigger  12  disposed on a handle  11 , and a muzzle  13  disposed at the front end of the main body  10 , a magazine  14  disposed under the muzzle  13  and interconnected with the muzzle  13 , and a nail feeder  15  disposed in the magazine  14  for continuously pushing the nails stored in the magazine  14  out towards the muzzle  13 ; wherein a through hole  141  is disposed on an upper wall of the magazine  14 ; an axle section  142  is protruded from a side of the magazine  14 ; and a transversal groove  143  is transversally disposed on the axle section  142 ;   a rotary rod  20 , disposed on an axial section  21 , and the axial section  21  having an axial hole  211  in the middle for allowing a screw rod  212  to pass through, and the axis of the rotary rod  20  being fixed in the transversal groove  143  of the axle section  142 ; a push arm  22  being extended forward from the front end of the axial section  21 ; an embedding plate  221  bent from the front end of the push arm  22 ; an embedding groove  222  disposed on the embedding plate  221 ; a blocking arm  23  being bent and extending in an aslant direction from the rear end of the axial section  21  towards the trigger  12 ; a blocking plate  231  being bent from the rear end of the blocking arm  23  and extended to the rear of the trigger  12 ; wherein a spring bracket  24  is disposed on an inner side of the rotary rod  20 , and a spring  241  is embedded in a position corresponding to a sidewall of the magazine  14  for providing the resilience for the rotary rod  20 ; further, a press arm  25  is extended from the rotary rod  20  having a press button  251  bent from the end of the press arm  25 ;   a limit plate  30 , movably passing into the through hole  141  of the magazine  14  and one side of the limit plate  30  being movably embedded into the embedding groove  222  of the rotary rod  20 ; wherein the limit plate  30  forms a latch  31  protruded from the inner wall of the magazine  14 .       

   Accompanied with the description of the foregoing structure, the principle of the movements for this invention is elaborated as follows: 
   Please refer to  FIG. 4  for the invention. If there is no nail in the magazine  14 , the spring bracket  24  of the rotary rod  20  will push the limit plate  30  towards the magazine  14  by a resilient force of the spring  241 , and then the blocking plate  231  will block the rear of the trigger  12 , such that if there is no nail in the magazine  14 , the blocking plate  231  will automatically block the rear of the trigger  12  to set the rotary rod  20  at a safety protection mode, and thus users cannot cock the trigger  12 . Such arrangement prevents the nail gun from being shot when there is no nail in the magazine, and thus protecting the structures including the firing device and the firing pin from being damaged by shooting without nails in the magazine or preventing the shortened life of use. 
   If nails are loaded in the magazine  14 , the nail feeder  15  in the magazine will continuously push the stored nails towards the muzzle  13 . When a nail is pushed to the top of the magazine  14  (as shown in  FIG. 5 ), the nail will automatically push the latch  31  out from the magazine  14  and drive the rotary rod  20  to rotate, and the blocking plate  231  will be separated automatically from the rear of the trigger  12  and switched to a free shooting mode, such that a user can freely cock the trigger to shoot out a nail in the magazine  14 . 
   Further, accompanied with the disposition of the press arm  25  and the press button  251 , after the last nail in the magazine  14  enters into the muzzle  13 , there will be no nail in the magazine  14  to press the latch  31 , and thus the rotary rod  20  will resume its original position by the resilient force pushed by the spring  241 , and the blocking plate  231  will block the rear of the trigger  12  and return to the safety protection mode, which causes the situation of unable to shoot the last nail. Users may manually press the press button  251  of the rotary rod  20  to separate the blocking plate  231  and manually switch the rotary rod to the free shooting mode for the shooting. Alternatively, if a nail in the magazine  14  is stuck or has other situations, users may make use of the press button  251  to cock the trigger and eliminate the failing conditions. 
   In summation of the above description, the present invention enhances the performance of the conventional structure, and further complies with the patent application requirements and is submitted to the Patent and Trademark Office for review and granting of the commensurate patent rights. 
   While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.