Patent Publication Number: US-6213372-B1

Title: Drive device for a nailing machine

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a drive device for a nailing machine for allowing the nailing machine to be operated in a successive nailing mode or a one-shot nailing mode. 
     2. Description of the Related Art 
     A wide variety of nailing machines has heretofore been provided. An example of which is U.S. Pat. No. 5,597,106 issued to Hamano, et al. on Jan. 28, 1997 that discloses a drive device for a nailing machine. The drive device allows the nailing machine to be operated in a successive nailing mode or a one-shot nailing mode. Yet, the structure of the drive device is relatively complicated. The present invention is intended to provide a simpler design for the drive device. 
     SUMMARY OF THE INVENTION 
     A nailing machine in accordance with the present invention comprises: 
     a housing containing a nail hitting mechanism for hitting nails; 
     a contact arm for pressing against a work; 
     a trigger lever having an end pivotally connected to the housing; 
     a contact lever having a lower end pivotally connected to the trigger lever and an upper end actuatable by the contact arm when the contact arm is pressed against the work; and 
     a pressing member comprising a first end pivotally connected to the trigger lever and a second end, the pressing member further comprising an arcuate portion on a side thereof; 
     whereby when the contact arm is firstly pressed against the work and the trigger lever is pulled subsequently to activate the nail hitting mechanism via transmission by the contact lever, the arcuate portion of the pressing member bears against the housing such that the contact lever is immobile when the contact arm is disengaged from the work and when the trigger lever is kept pulled after hitting the nail to the work, the nailing machine being thus in a one-shot mode; and 
     whereby when the trigger lever is firstly pulled such that the second end of the trigger lever bears against the housing, and the contact arm is subsequently pressed against the work and thus actuates the contact lever to activate the nail hitting mechanism for hitting a nail, the contact lever is returned to its original position when the contact arm is disengaged from the work and when the trigger lever is kept pulled after hitting the nail, the nailing machine being thus in a successive nailing mode. 
     The housing comprises an indent and a corner adjacent to the indent. The arcuate portion of the pressing member is pressed against the corner of the housing and the second end of the pressing member enters the indent when the contact arm is pressed against the work and when in the one-shot nailing mode. 
     Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a nailing machine with a drive device in accordance with the present invention. 
     FIG. 2 is a partial perspective view of the nailing machine in accordance with the present invention. 
     FIG. 2A is a perspective view of the drive device in accordance with the present invention. 
     FIG. 3 is a partial perspective view, partly exploded, of the nailing machine in accordance with the present invention. 
     FIG. 4 is a partial sectional view of the nailing machine in accordance with the present invention, wherein the nailing machine is in a one-shot mode wherein the contact arm is going to press against an work to be nailed and the trigger lever is not pulled. 
     FIG. 5 is a sectional view similar to FIG. 4, wherein contact arm has been pressed against the work and the trigger lever is then pulled. 
     FIG. 6 is a sectional view similar to FIG. 4, wherein the nailing machine is in a successive nailing mode wherein the trigger lever is pulled firstly yet the contact arm has not yet been pressed against the work. 
     FIG. 7 is a sectional view similar to FIG. 6, wherein the contact arm has been pressed against the work. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1,  2 ,  2 A, and  3 , a nailing machine  1  generally comprises a housing  15  containing a nail hitting mechanism (not shown) and a drive valve (not shown) for driving the nail hitting mechanism. The nailing machine  1  comprises a drive device in accordance with the present invention. The nailing machine  1  includes a contact arm  21  that is pressed against a work (nail receiving member) when desired. The nailing machine  1  includes a spring  211  is provided for returning the contact arm  21  to its original position. The drive device for the nailing machine  1  includes a trigger lever  11  to which a contact lever  22  and a pressing member  23  are attached. The housing  15  includes an indent  16  and a corner  121  adjacent to the indent  16 . 
     As illustrated in FIG. 3, the trigger lever  11  includes first, second, and third pin holes  1101 ,  1102 , and  1103 . A pin  1111  is extended through the pin holes  1101  in the trigger lever  11  and a pin hole  10  in the housing  15 , thereby pivotally attaching an upper end  114  of the trigger lever  11  to the housing  15 . The upper end  114  of the trigger lever  11  includes an opening  112  through which the contact arm  21  extends to thereby be in contact with an upper end of the contact lever  22 , best shown in FIG.  4 . The contact lever  22  includes two lateral wings  222  having a space therebetween. The lateral wings  222  include aligned pin holes  220  in lower ends thereof. A pin  1112  is extended through the pin holes  1102  of the trigger lever  11  and the pin holes  220  of the contact lever  22 , thereby pivotally attaching a lower end  221  of the contact lever  22  to a mediate portion of the trigger lever  11 . 
     Still referring to FIG. 3, the pressing member  23  includes a hole  230  in a first end  231  thereof. A pin  1113  is extended through the pin holes  1103  of the trigger lever  11  and the pin hole  230  of the pressing member  23 . Springs  241  and  242  are provided to the contact lever  22  and the pressing member  23  for returning the contact lever  22  and the pressing member  23  to their original positions, respectively. As illustrated in FIG. 4, the pressing member  23  is located below the contact lever  22  with an end face  233  of a second end of the pressing member  23  facing the housing  15  of the nailing machine  1 . The pressing member  23  further includes an arcuate portion  232  (FIG. 3) on a side thereof. 
     When in a one-shot nailing mode, the trigger lever  11  is not pulled before a front end  210  of the contact arm  21  is pressed against the work. As illustrated in FIG. 4, the nailing machine is in a one-shot mode wherein the front end  210  of the contact arm  21  is going to press against a work (not labeled) to be nailed and the trigger lever  11  is not pulled. Referring to FIG. 5, when the front end  210  of the contact arm  21  has been pressed against the work and the trigger lever is pulled subsequently, the contact lever  22  is moved rightward to actuate a trigger valve stem  12  of the drive valve that actuates the nail hitting mechanism. It is noted that even though the trigger lever  11  is kept pulled in a position shown in FIG. 5, the arcuate portion  232  of the pressing member  23  bears against the corner  121  of the housing  15  such that the contact lever  22  and the trigger valve stem  12  are immobile even if the front end  210  of the contact arm  21  is disengaged from the work. Namely, the spring  211  may return the contact arm  21  when the front end  210  of the contact arm  21  is disengaged from the work, yet the contact lever  22  and the trigger valve stem  12  cannot be returned, as they are retained in place. Thus, the nailing machine operates in a one-shot nailing mode even though the trigger lever  11  is kept pulled. The second end of the pressing member  23  enters the indent  16  when in the one-shot mode. 
     When successive nailing mode is required, referring to FIG. 6, the trigger lever  11  is pulled firstly before the front end  210  of the contact arm  21  presses against the work. It is noted that the pressing member  23  bears against the corner  121  of the housing  15  at the end face  233  thereof instead of the arcuate portion  232 . A fixed space  200  is defined between the trigger lever  11  and the housing  15 . Referring to FIG. 7, when the front end  210  of the contact arm  21  is pressed against the work, the contact lever  22  is moved rightward to actuate the trigger valve stem  12  of the drive valve that actuates the nail hitting mechanism. After hitting a nail to the work, the front end  210  of the contact arm  21  is disengaged from the work and moves forward to its original position. The contact lever  22  and the trigger valve stem  12  also return to their original positions. A successive nailing mode is obtained if the trigger lever  11  is kept pulled by the user for hitting nails successively. 
     According to the above description, it is appreciated that the drive device in accordance with the present invention allows the nailing machine to be operated in a successive nailing mode or a one-shot nailing mode, yet the overall arrangement is much simpler. 
     Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the invention as hereinafter claimed.