Patent Publication Number: US-7213735-B1

Title: Staple-driving gun capable of ensuring attachment of a seal washer to a sleeve

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a staple-driving gun, more particularly to a staple-driving gun capable of ensuring attachment of a seal washer to a sleeve. 
   2. Description of the Related Art 
   Referring to  FIG. 1 , a conventional staple-driving gun is shown to include a gun body  1 , a staple cartridge  3 , and a piston unit  2 . 
   The gun body  1  includes a handle  102 , a staple-discharging member  103  formed with a staple-discharging hole  1032  that extends along an axis, and a hollow housing  101  connected fixedly to the handle  102  and having a first open end  1011 , and a second open end  1012  opposite to the first open end  1011  along the axis and connected to the staple-discharging member  103 . The housing  101  is configured with an inner surface that is divided into first and second air chambers  105 ,  106  by a partition  104  that is disposed fixedly in the housing  101  and that is formed with a valve hole  104 ′. The housing  101  is formed with an air inlet  109  in spatial communication with the first air chamber  105  for permitting compressed air to be fed into the first air chamber  105  therethrough. 
   The staple cartridge  3  is attached fixedly to the staple-discharging member  103 , and is capable of receiving a row of staples (not shown) so as to feed the staples into the staple-discharging hole  1032  in the staple-discharging member  103  one at a time. 
   The piston unit  20  includes: a sleeve  201  disposed in the first air chamber  15 , and having a coupling end portion  205  disposed movably in the first open end  1011  of the housing  101 , and an enlarged valve end portion  207  disposed movably in the second air chamber  106 , having an outer diameter larger than a diameter of the valve hole  104 ′ in the partition  104 , and having an annular outer surface  2071  formed with an annular engaging groove  2072 ; a seal washer  209  sleeved on the valve end portion  207  of the sleeve  201  in a close fitting manner and having an inwardly extending annular flange  2091  that engages the annular engaging groove  2072  in the valve end portion  207  of the sleeve  201 ; an operating member  206  connected fixedly to the coupling end portion  205  of the sleeve  201 , disposed outwardly of the housing  101 , and movable along the axis; and a piston rod  202  disposed movably in the sleeve  202  and having a diameter-increased first piston end  2021  that is in slidable and sealing contact with the sleeve  201 , and a second piston end  2022  opposite to the first piston end  2021  along the axis, extending outwardly of the sleeve  201 , and disposed movably and sealingly in the second air chamber  106 . The second piston end  2022  of the piston rod  202  has a fixed staple-striking piece  204  that extends along the axis into the staple-discharging hole  1032  in the staple-discharging member  103 . 
   The operating member  206  is operable so as to move the sleeve  201  from a standby position, where the seal washer  209  is in sealing contact with the partition  104  so as to seal the valve hole  104 ′ in the partition  104  such that flow of the compressed air from the first air chamber  105  into the second air chamber  106  through the valve hole  104 ′ in the partition  104  is prevented, as shown in  FIG. 1 , to a staple-discharging position, where the valve end portion  207  of the sleeve  201  is separated from the partition  104  so as to allow flow of the compressed air from the first air chamber  105  into the second air chamber  106  through the valve hole  104 ′ in the partition  104  such that the compressed air flowing from the first air chamber  105  into the second air chamber  106  via the valve hole  104 ′ in the partition  104  urges the second piston end  2022  of the piston rod  202  to move toward the second open end  1012  of the housing  101 , thereby discharging one of the staples in the staple-discharging hole  1032  in the staple-discharging member  103  in response to one strike of the staple-striking piece  204  thereon, as shown in  FIG. 2 . 
   It is noted that, when the sleeve  201  is moved from the standby position to the staple-discharging position, the annular flange  2091  of the seal washer  209  is removed from the annular engaging groove  2072  in the valve end portion  207  of the sleeve  201  by the compressed air flowing from the first air chamber  105  into the second air chamber  106 , thereby resulting in deformation of the seal washer  209 , as best shown in  FIG. 3 . As such, after staple discharging, the annular flange  2091  hardly restores to once again engage the annular engaging groove  2072  in the valve end portion  207  of the sleeve  201  such that attachment of the seal washer  209  to the valve end portion  207  of the sleeve  201  cannot be ensured. 
   SUMMARY OF THE INVENTION 
   Therefore, the object of the present invention is to provide a staple-driving gun that is capable of ensuring attachment of a seal washer to a sleeve. 
   According to the present invention, a staple-driving gun comprises: 
   a gun body including
         a handle,   a hollow housing connected fixedly to the handle, and having first and second open ends opposite to each other along an axis, the housing being configured with an inner space and further having a partition disposed fixedly in the inner space so as to divide the inner space into a first air chamber disposed adjacent to the first open end, and a second air chamber disposed adjacent to the second open end, the partition being formed with a valve hole, the axis extending through the valve hole in the partition, the housing being formed with an air inlet in spatial communication with the first air chamber for permitting compressed air to be fed into the first air chamber therethrough, and   a staple-discharging member mounted on the second open end of the housing and formed with a staple-discharging hole that extends along the axis;       

   a staple cartridge attached fixedly to the staple-discharging member, and adapted to receive a row of staples so as to feed the staples into the staple-discharging hole in the staple-discharging member one at a time; and 
   a piston unit including
         a sleeve disposed in the first air chamber, movable along the axis, and having a coupling end portion disposed movably in the first open end of the housing, and an enlarged valve end portion disposed movably in the second air chamber and having an outer diameter larger than a diameter of the valve hole in the partition, the valve end portion of the sleeve having an annular outer surface formed with an annular engaging groove, and being formed with an air-excluding hole in spatial communication with the annular engaging groove,   a seal washer sleeved on the valve end portion of the sleeve in a close fitting manner and having an inwardly extending annular flange that engages the annular engaging groove in the valve end portion of the sleeve,   an operating member connected fixedly to the coupling end portion of the sleeve, disposed outwardly of the housing, and movable along the axis, and   a hollow piston rod disposed movably in the sleeve and having a diameter-increased first piston end that is in slidable and sealing contact with the sleeve, a second piston end that is opposite to the first piston end along the axis, that extends outwardly of the sleeve, and that is disposed movably and sealingly in the second air chamber, and an intermediate rod portion disposed between and interconnecting the first and second piston ends, the second piston end of the piston rod having a fixed staple-striking piece that extends along the axis into the staple-discharging hole in the staple-discharging member.       

   The operating member is operable so as to move the sleeve from a standby position, where the seal washer is in sealing contact with the partition and the valve end portion of the sleeve so as to seal the valve hole in the partition such that flow of the compressed air from the first air chamber into the second air chamber through the valve hole in the partition is prevented, to a staple-discharging position, where the valve end portion of the sleeve is separated from the partition so as to allow flow of the compressed air from the first air chamber into the second air chamber through the valve hole in the partition such that the compressed air flowing from the first air chamber into the second air chamber via the valve hole in the partition urges the second piston end of the piston rod to move toward the second open end of the housing, thereby discharging one of the staples in the staple-discharging hole in the staple-discharging member in response to one strike of the staple-striking piece thereon. 
   When the sleeve is moved from the standby position to the staple-discharging position, at least one portion of the annular flange of the seal washer is removed from the annular engaging groove in the valve end portion of the sleeve by the compressed air flowing from the first air chamber into the second air chamber, thereby forming a gap between the valve end portion of the sleeve and the annular flange of the seal washer. The gap is in spatial communication with and cooperates with the air-excluding hole in the valve end portion of the sleeve so as to constitute an air-excluding passage for excluding the compressed air from the annular engaging groove in the valve end portion of the sleeve. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which: 
       FIG. 1  is a schematic sectional view of a conventional staple-driving gun; 
       FIG. 2  is a schematic sectional view of the conventional staple-driving gun when a sleeve is moved to a staple-discharging position by a normal operation of an operating member; 
       FIG. 3  is a fragmentary schematic sectional view illustrating a deformed seal washer sleeved on the sleeve of the conventional staple-driving gun; 
       FIG. 4  is a schematic sectional view showing the preferred embodiment of a staple-driving gun according to the present invention; 
       FIG. 5  is a schematic sectional view showing the preferred embodiment when a sleeve is moved to a staple-discharging position; 
       FIG. 6  is a fragmentary schematic sectional view illustrating a seal washer sleeved on the sleeve of the preferred embodiment; and 
       FIG. 7  is a fragmentary schematic sectional view illustrating deformation of the seal washer when the sleeve is in the staple-discharging position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 4 , the preferred embodiment of a staple-driving gun according to the present invention is shown to include a gun body  10 , a staple cartridge  30 , and a piston unit  20 . 
   The gun body  10  includes a handle  12 , a hollow housing  11 , and a staple-discharging member  13 . 
   The housing  11  is connected fixedly to the handle  12 , and has first and second open ends  111 ,  112  opposite to each other along an axis (L). The housing  11  is configured with an inner space  17 , and has a partition  14  disposed fixedly in the inner space  17  and perpendicular to the axis (L) so as to divide the inner space  17  into a first air chamber  15  disposed adjacent to the first open end  111 , and a second air chamber  16  disposed adjacent to the second open end  112 . The partition  14  is formed with a valve hole  141 . The axis (L) extends through the valve hole  141  in the partition  14 . The housing  11  is formed with an air inlet  113  in spatial communication with the first air chamber  15  for permitting compressed air to be fed into the first air chamber  15  therethrough. 
   The staple-discharging member  13  is mounted on the second open end  112  of the housing  11 , and is formed with a staple-discharging hole  132  that extends along the axis (L). 
   The staple cartridge  30  is attached fixedly to the staple-discharging member  13 , and is adapted to receive a row of staples (not shown) so as to feed the staples into the staple-discharging hole  132  in the staple-discharging member  13  one at a time. 
   The piston unit  20  includes a sleeve  21 , a seal washer  25 , an operating member  23 , and a hollow piston rod  22 . 
   The sleeve  21  is disposed in the first air chamber  15 , and is movable along the axis (L). The sleeve  21  has a coupling end portion  211  disposed movably in the first open end  111  of the housing  11 , and an enlarged valve end portion  212  disposed movably in the second air chamber  16  and having an outer diameter larger than a diameter of the valve hole  141  in the partition  14 . With further reference to  FIG. 6 , the valve end portion  212  of the sleeve  21  has an annular outer surface  2121  formed with an annular engaging groove  2122 , and is formed with an air-excluding hole  2123  in spatial communication with the annular engaging groove  2122 . In this embodiment, the sleeve  21  is formed with a plurality of air guiding holes  213  disposed adjacent to the valve end portion  212 . The sleeve  21  further has a radially and inwardly extending integral inward flange  214  that is disposed between the valve end portion  212  and the air guiding holes  213 . 
   The seal washer  25  is sleeved on the valve end portion  212  of the sleeve  21  in a close fitting manner, and has an inwardly extending annular flange  251  that engages the annular engaging groove  2122  in the valve end portion  212  of the sleeve  21 , as best shown in  FIG. 6 . 
   The operating member  23  is connected fixedly to the coupling end portion  211  of the sleeve  21 , is disposed outwardly of the housing  11 , and is movable along the axis (L). In this embodiment, the operating member  23  is formed with an air outlet  231 . 
   The piston rod  22  is disposed movably in the sleeve  21 , and has a diameter-increased first piston end  221 , a second piston end  222 , and an intermediate rod portion  223 . The first piston end  221  of the piston rod  22  is in slidable and sealing contact with the sleeve  21 . The second piston end  222  of the piston rod  22  is opposite to the first piston end  221  along the axis (L), extends outwardly of the sleeve  21 , and is disposed movably and sealingly in the second air chamber  16 . The intermediate rod portion  223  of the piston rod  22  is disposed between and interconnects the first and second piston ends  221 ,  222 , and is in slidable and sealing contact with the inward flange  214  of the sleeve  21 . The second piston end  222  of the piston rod  22  has a fixed staple-striking piece  24  that extends along the axis (L) into the staple-discharging hole  132  in the staple-discharging member  13 . In this embodiment, the sleeve  21  cooperates with the piston rod  22  to define a volume-changeable annular third air chamber  27  among the inward flange  214  of the sleeve  21 , and the first piston end  221  and the intermediate rod portion  223  of the piston rod  22 . The air guiding holes  213  in the sleeve  21  are in spatial communication with the first and third air chambers  15 ,  27 . In this embodiment, the piston rod  22  defines an inner axial hole  220 , and is formed with a through hole  224  disposed adjacent to the second piston end  222  and in spatial communication with the inner axial hole  220 . The inner axial hole  220  has an open end  2201  formed in the first piston end  221  of the piston rod  22 , and a closed end  2202  disposed adjacent to the second piston end  222  of the piston rod  22 . The through hole  224  and the inner axial hole  220  in the piston rod  22  cooperate with the air outlet  231  in the operating member  23  to constitute an air discharging passage. 
   In use, the operating member  23  of the piston unit  20  is operable so as to move the sleeve  21  from a standby position, where the seal washer  25  is in sealing contact with the partition  14  and the valve end portion  212  of the sleeve  21  so as to seal the valve hole  141  in the partition  14  such that flow of the compressed air from the first air chamber  15  into the second air chamber  16  through the valve hole  141  in the partition  14  is prevented, as shown in  FIG. 4 , to a staple-discharging position, where the valve end portion  212  of the sleeve  21  is separated from the partition  14  so as to allow flow of the compressed air from the first air chamber  15  into the second air chamber  16  through the valve hole  141  in the partition  14  such that the compressed air flowing from the first air chamber  15  into the second air chamber  16  via the valve hole  141  in the partition  14  urges the second piston end  222  of the piston rod  22  of the piston unit  20  to move toward the second open end  112  of the housing  11 , thereby discharging one of the staples in the staple-discharging hole  132  in the staple-discharging member  13  in response to one strike of the staple-striking piece  24  thereon, as shown in  FIG. 5 . Thereafter, the compressed air in the second air chamber  16  is discharged to the outside via the air-discharging passage, and simultaneously, the compressed air flowing from the first air chamber  15  into the third air chamber  27  via the air guiding holes  213  in the sleeve  21  urges the first piston end  221  of the piston rod  22  toward the first open end  111  of the housing  11 . 
   It is noted that, when the sleeve  21  is moved from the standby position to the staple-discharging position, at least one portion of the annular flange  251  of the seal washer  25  is removed from the annular engaging groove  2122  in the valve end portion  212  of the sleeve  21  by the compressed air flowing from the first air chamber  15  into the second air chamber  16 , thereby forming a gap  2124  between the valve end portion  212  of the sleeve  21  and the annular flange  251  of the seal flange  25 , as best shown in  FIG. 7 . In this case, the gap  2124  is in spatial communication with and cooperates with the air-excluding hole  2123  in the valve end portion  212  of the sleeve  21  so as to constitute an air-excluding passage for excluding the compressed air from the annular engaging groove  2122  in the valve end portion  212  of the sleeve  21 . 
   As such, due to the presence of the air-excluding hole  2123  in the valve end portion  212  of the sleeve  21 , the compressed air in the annular engaging groove  2122  in the valve end portion  212  of the sleeve  21  can be effectively excluded such that the annular flange  251  of the seal washer  25  can be easily restored to engage the annular engaging groove  2122  in the valve end portion  212  of the sleeve  21  when the sleeve  21  is moved from the staple-discharging position back to the standby position. In view of this, deformation of the seal washer  25  occurring in the aforesaid conventional staple-driving gun can be avoided even after a long period of use, thereby ensuring attachment of the seal washer  25  to the valve end portion  212  of the sleeve  21 . 
   While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.