Patent Publication Number: US-2022219302-A1

Title: Retaining device for use with a nail gun

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority of Taiwanese Patent Application No. 110101302, filed on Jan. 13, 2021. 
     FIELD 
     The disclosure relates to an electric nail gun, and more particularly to a retaining device for use with an electric nail gun having a flywheel. 
     BACKGROUND 
     A conventional electric nail gun disclosed in Japanese Patent Publication No. 2020082302 includes a flywheel that is rotatable by electric power, a driver that is configured to be driven by rotation of the flywheel to strike a nail, a returning mechanism that moves the driver to its original position after the striking, and a stopping mechanism that restricts movement of the driver after the driver returns to the original position. During a nail-striking process, the stopping member is disengaged from the driver, so that the driver can be pushed by a pushing member to contact a pressure roller. The pressure roller then pushes the driver to contact the flywheel to perform the striking operation. 
     When the nail-striking process is completed and the driver is moved to its original position by the returning mechanism, movement of the driver is restricted by the stopping mechanism such that the driver is prevented from being accidentally driven to strike the nail. However, the stopping mechanism of the conventional electric nail gun has a rather complex configuration, which makes it difficult for installation and maintenance. 
     SUMMARY 
     Therefore, the object of the disclosure is to provide a retaining device for use with an electric nail gun that has a simpler structure for easy installation and maintenance. 
     According to the disclosure, a retaining device is adapted for use with a nail gun. The nail gun includes a frame, and a flywheel that is rotatably mounted to the frame. The retaining device includes a swing arm unit, an impact unit, a retrieving unit and a positioning unit. 
     The swing arm unit is adapted to be pivoted to the frame, and is adapted to swing relative to the frame between a proximate position, where the swing arm unit is proximate to the flywheel, and a distal position, where the swing arm unit is distal from the flywheel. The impact unit is movably connected to the swing arm unit, is adapted to swing with the swing arm unit relative to the frame, and is movable in a striking direction, and a retrieving direction opposite to the striking direction between a pre-striking position, where the impact unit is proximate to the flywheel, and a striking position, where the impact unit is distal from the flywheel. The retrieving unit is connected between the impact unit and the swing arm unit, and is configured to bias the impact unit to move in the retrieving direction to the pre-striking position. The positioning unit includes at least one first positioning member that is connected to the swing arm unit and that extends along the striking direction, and at least one second positioning member that is connected to the impact unit, that extends along the striking direction, and that is configured to be telescopically engaged with and in frictional contact with the at least one first positioning member when the impact unit is at the pre-striking position, so as to position the impact unit on the swing arm unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the disclosure will become apparent in the following detailed description of the embodiment with reference to the accompanying drawings, of which: 
         FIG. 1  is a schematic side view of an embodiment of a retaining device according to the disclosure being mounted in a nail gun; 
         FIG. 2  is an exploded perspective view of the embodiment; 
         FIG. 3  is a fragmentary perspective view of the nail gun; 
         FIG. 4  is a fragmentary sectional view of the nail gun illustrating an impact unit being at a pre-striking position and a swing arm unit being at a distal position; 
         FIG. 5  is a fragmentary sectional view similar to  FIG. 4 , but illustrating that the swing arm unit is at a proximate position; 
         FIG. 6  is a fragmentary sectional view similar to  FIG. 5 , but illustrating that the impact unit is at a striking position; and 
         FIG. 7  is a fragmentary sectional similar to  FIG. 6 , but illustrating that the impact unit moves from the striking position toward the pre-striking position. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1, 2 and 3 , an embodiment of a retaining device according to the disclosure is adapted for use in a electric nail gun  1 . The nail gun  1  includes a frame  11 , a flywheel  12  that is rotatably mounted to the frame  11 , a motor unit  13  that drives the flywheel  12  to rotate by electric power, and a trigger unit  14  and a safety unit  15  that are movably installed on the frame  11  for manual operation. The trigger unit  14  and the safety unit  15  are configured to determine whether the motor unit  13  is activated and whether to perform a nail-striking action. The retaining device includes a swing arm unit  2 , an impact unit  3 , a retrieving unit  4 , and a positioning member  5 . 
     The swing arm unit  2  extends along a striking direction (X 1 ) and is adapted to be spaced apart from the flywheel  12 . The swing arm unit  2  includes a pivot portion  21  that is adapted to be pivoted to the frame  11 , and a swinging portion  22  that is opposite to the pivot portion  21  and that is adapted to be spaced apart from the flywheel  12 . 
     The swing arm unit  2  is adapted to be operated by the trigger unit  14  to swing relative to the frame  11  between a distal position (see  FIGS. 1 and 4 ), where the swinging portion  22  is distal from the flywheel  12 , and a proximate position (see  FIGS. 5 and 6 ), where the swinging portion  22  is proximate to the flywheel  12 . 
     The impact unit  3  is movably connected to the swing arm unit  2 , and is adapted to swing with the swing arm unit  2  relative to the frame  11 . The impact unit includes an impact member  31  that is movably connected to the swing arm unit  2 , and a striking rod  32  that is co-movably connected to the impact member  31  and that is adapted for striking a nail (not shown). 
     The impact unit  3  is movable in the striking direction (X 1 ) and a retrieving direction (X 2 ) opposite to the striking direction (X 1 ) between a pre-striking position (see  FIGS. 4 and 5 ), where the impact member  31  of the impact unit  3  is proximate to the swinging portion  22  of the swing arm unit  2  and is proximate to the flywheel  12 , and a striking position (see  FIG. 6 ), where the impact member  31  is proximate to the pivot portion  21  of the swing arm unit  2  and is distal from the flywheel  12 . When the impact unit  3  is at the pre-striking position and when the swing arm unit  2  swings from the distal position to the proximate position, the impact member  31  of the impact unit  3  is brought into contact with the flywheel  12  so as to be driven by rotation of the flywheel  12  to move toward the striking position. 
     The retrieving unit  4  includes two resilient members  41  that are connected between the swing arm unit  2  and the impact member  31  of the impact unit  3 , that extend along the striking direction (X 1 ), and that are spaced apart from each other along a transverse direction (Y) being transverse to the striking direction (X 1 ). The resilient members  41  are configured to bias the impact unit  3  to move in the retrieving direction (X 2 ) to the pre-striking position. In the present embodiment, each of the resilient members  41  is a spring and has a plurality of spring coils  411 . The striking direction (X 1 ) and the transverse direction (Y) are substantially perpendicular to each other. 
     It should be noted that the number of the resilient members  41  is not limited to two. In variations of the embodiment, the number of the resilient member  41  may be one or more than two. 
     The positioning unit  5  includes two first positioning members  51 , two second positioning members  52  and a plurality of gaskets  53 . The first positioning members  51  extend along the striking direction (X 1 ), are spaced apart from each other along the transverse direction (Y), and are connected respectively and non-movably to opposite sides of the swing arm unit  2 . The second positioning members  52  extend along the striking direction (X 1 ), are spaced apart from each other along the transverse direction (Y), and are connected respectively and non-movably to opposite sides of the impact unit  3 . 
     The first and second positioning members  51 ,  52  are connected among the resilient members  41  of the retrieving unit  4 , the swing arm unit  2  and the impact unit  3 . Specifically, each of the resilient members  41  has one end connected to the swing arm unit  2  via a respective one of the first positioning members  51  and the other end connected to the impact unit  3  via a respective one of the second positioning members  52 . 
     When the impact unit  3  is at the pre-striking position, each of the second positioning members  52  is configured to be telescopically engaged with and in frictional contact with a respective one of the first positioning members  51 , so as to position the impact unit  3  on the swing arm unit  2  (see  FIGS. 4 and 5 ). When the impact unit  3  is at the striking position, each of the second positioning members  52  is configured to be spaced apart from the respective one of the first positioning members  51  (see  FIG. 6 ). 
     Referring to  FIGS. 2 and 4 , each of the first positioning members  51  has a first connecting end portion  511  that is detachably connected to the swing arm unit  2 , a rod portion  512  that is opposite to the first connecting end portion  511  along the striking direction (X 1 ), and that extends along the striking direction (X 1 ), and a plurality of first engaging holes  513  that are provided for one end of a respective one of the resilient members  41  to extend therethrough. 
     Each of the second positioning members  52  has a second connecting end portion  521  that is detachably connected to the impact unit  3 , a surrounding wall portion  522  that is opposite to the second connecting end portion  521  along the retrieving direction (X 2 ), and a plurality of second engaging holes  523  that are provided for the other end of the respective one of the resilient members  41  to extend therethrough. The surrounding wall portion  522  of each of the second positioning members  52  surrounds and defines a receiving room  520  that has an end  524  being open toward the respective one of the first positioning members  51 , and is formed with an air discharging hole  525  that spatially communicates the receiving room  520  with the external environment. 
     Each of the gaskets  53  is sleeved on the rod portion  512  of one of the first positioning members  51  such that, when the impact unit  3  is at the pre-striking position, each of the gaskets  53  is disposed between and in frictional contact with the rod portion  512  of the one of the first positioning members  51  and the surrounding wall portion  522  of a corresponding one of the second positioning members  52  to provide an airtight seal. 
     It should be noted that the number of the first and second positioning members  51 ,  52  may vary as long as the number of the first positioning members  51  is the same as that of the second positioning members. It should also be noted that the resilient members  41  are not limited to be connected to the first and second positioning members  51 ,  52 . In variations of the embodiment, the resilient members  41  may be directly connected to the swing arm unit  2  and the impact unit  3  without the first and second positioning members  51 ,  52 . 
     Referring again to  FIGS. 1 and 4 , prior to an operation of the nail gun  1 , the swing arm unit  2  is at the distal position (i.e., the swinging portion  22  of the swing arm unit  2  is distal from the flywheel  12 ) and the impact unit  3  is at the pre-striking position, such that the impact member  31  is proximate to and spaced apart from the flywheel  12 . At this time, the rod portion  512  of each of the first positioning members  51  is received in the receiving room  520  of the respective one of the second positioning members  52  such that each of the first positioning members  51  is positioned relative to the respective one of the second positioning members  52  via friction between the corresponding gaskets  53  and the surrounding wall portion  522 , thereby prohibiting removal of the impact unit  3  from the pre-striking position. 
     Referring to  FIGS. 1 and 5 , during the operation, when the flywheel  12  starts to rotate to a predetermined speed, a user may operate the trigger unit  14  to enter a single-striking mode, or operate both the trigger unit  14  and the safety unit  15  in order to enter a sequential-striking mode. Then, the swing arm unit  2  is driven to swing toward the flywheel  12  to the proximate position and bring the impact member  31  at the pre-striking position toward the flywheel  12 . Once the impact member  31  is brought into contact with the flywheel  12 , the impact unit  3  is urged by the rotation of the flywheel  12  to overcome the friction between the gaskets  53  and the second positioning members  52 , so as to move in the striking direction (X 1 ) from the pre-striking position toward the striking position (see  FIG. 6 ). After the striking rod  32  of the impact unit  3  strikes the nail (not shown), the swing arm unit  2  returns from the proximate position to the distal position (see  FIG. 7 ), and the impact unit  3  is subjected to the biasing force of the resilient members  41  to move in the retrieving direction (X 2 ) from the striking position toward the pre-striking position. 
     Specifically, referring to  FIGS. 4 and 7 , when the impact unit  3  is driven by the resilient members  41  to move toward the pre-striking position, the surrounding wall portion  522  of each of the second positioning members  52  becomes sleeved on the rod portion  512  of the respective one of the first positioning members  51  in an airtight manner, forcing a portion of air in the receiving room  520  to flow out through the air discharging hole  525  and generating a damping effect. As a result, the telescopic engagement between the first and second positioning members  51 ,  52  prohibits potential movement of the impact unit  3  caused by oscillatory motion of the resilient members  41 , and thus prevents the impact unit  3  from accidentally striking the nail. 
     It should be noted that, since the impact unit  3  is configured to swing with the swing arm unit  2 , the telescopic engagement between the first and second positioning members  51 ,  52  is not affected by the movement of the swing arm unit  2  between the distal position and the proximate position. 
     In sum, the present embodiment of the retaining device for use in the nail gun has benefits as follows. By virtue of the positioning effect provided by the first and second positioning members  51 ,  52 , the impact unit  3  is prevented from accidentally striking the nail after returning from the striking position to the pre-striking position. In addition, compared with the prior art, the retaining device of the present disclosure is able to provide the same function with a simpler structure, which is easier for installation and maintenance. 
     In the description above, for the purposes of explanation, numerous specific details have been set forth in order to provide a thorough understanding of the embodiment. It will be apparent, however, to one skilled in the art, that one or more other embodiments may be practiced without some of these specific details. It should also be appreciated that reference throughout this specification to “one embodiment,” “an embodiment,” an embodiment with an indication of an ordinal number and so forth means that a particular feature, structure, or characteristic may be included in the practice of the disclosure. It should be further appreciated that in the description, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of various inventive aspects, and that one or more features or specific details from one embodiment may be practiced together with one or more features or specific details from another embodiment, where appropriate, in the practice of the disclosure. 
     While the disclosure has been described in connection with what is considered the exemplary embodiment, it is understood that this disclosure 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.