Patent Publication Number: US-2010127035-A1

Title: Braking Mechanism for Nail Guns

Description:
BACKGROUND 
     The present invention relates to braking mechanisms, and particularly relates to a braking mechanism for a nail gun. 
     Generally, braking mechanisms are used in nail guns to automatically detect whether there are adequate nails in magazines and brake the shooting action of nail guns if there is no nail in the magazine. Usually, the braking mechanism disable the trigger valve of nail guns thereby reminding of the operator to reload nails. 
     For example, Taiwan patent No. 321044 discloses such a braking mechanism for a nail gun, in which a sliding member is employed to push nails into nail driving track. A braking member is formed on a side of the sliding member. The sliding member is opposite to a safety rod of the nail gun. The braking member moves to the safety rod together with the sliding member at a displacement of a thickness of the nail when a nail is shot out of the nail gun. To ensure that the safety rod can move freely in upward and downward direction when there is only one nail in the nail track, a distance between the braking member and the safety rod should be equal to a distance between the sliding member and the nail driving track. As such, the sliding member enters into the nail driving track when the last nail is shot out of the nail gun, and the braking member moves to a position at which the braking member is capable of blocking the safety rod such that the safety rod can&#39;t move upwardly. As a result, the nail gun is braked. The operator needs to reload nails into the nail track. Generally, fine nails are popularly used in nail guns, for example, mosquito nails which have thickness of about 1.2 millimeters. 
     However, the braking member can merely move at a distance equals to the thickness of the last nail (e.g. about 1.2 millimeters) after the last nail is shot out of the nail gun. In other words, the braking member blocks the safety rod using an area having a width that is equal to about 1.2 millimeters. In such conditions, if the operator presses the trigger forcedly the safety rod may slide off the braking member. As a result, the braking mechanism fails to brakes the shooting action. 
     Therefore, there is a desire to improve a stability of barking of shooting action. 
     BRIEF SUMMARY 
     To overcome aforementioned problems, an object of the present invention is to provide a braking mechanism for a nail gun, and particularly to provide a braking mechanism in which: a braking portion is capable of moving along a curved path to a position at which the braking portion can prevent the safety rod from moving upwardly under improved contact area. As such, a stability of braking of shooting action is also improved. 
     In one embodiment, a braking mechanism for a nail gun is provided. The nail gun includes a nail driving track, a magazine and an inner trigger for controlling a shooting action of the nail gun. The braking mechanism includes a safety rod, a sliding member, a swing stem, and a guide plate. The sliding member is slidably received in the magazine. The sliding member is configured for pushing nails received in the magazine into the nail driving track. The swing stem is resiliently and pivotally mounted on the sliding member. The swing stem includes a braking portion. A straight path is defined between the safety rod and the barking portion. A protrusion is formed on the braking portion. The guide plate is disposed at an end of the straight path. The guide plate is configured for guiding the protrusion such that the braking portion moves away from the straight path. The swing stem is capable of sliding off the guide plate as the sliding member moves to the nail driving track such that the braking portion moves back to the straight path to block the safety rod thereby braking shooting action of the nail gun. 
     The present braking mechanism for a nail gun will be described in detail with reference to figures together as following: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which: 
         FIG. 1  is an exploded perspective view of a braking mechanism for nail guns in accordance with an embodiment; 
         FIG. 2  is a cross sectional view of the braking mechanism of  FIG. 1 ; 
         FIG. 3  is another cross sectional view of the braking mechanism of  FIG. 1 ; 
         FIG. 3   a  is an partially enlarged view of the  FIG. 3 ; 
         FIG. 4  is a schematic view showing an operation state of the braking mechanism of  FIG. 1 ; 
         FIG. 5  is a schematic view showing an operation state of a guide plate and a swing stem in the braking mechanism of  FIG. 1 ; 
         FIG. 6  is another schematic view showing an operation state of the braking mechanism of  FIG. 1 ; and 
         FIGS. 7   a  to  7   g  are schematic view showing successive operating state of the braking mechanism of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exploded perspective view of a braking mechanism for a nail gun in accordance with a first embodiment. The nail gun includes a magazine  2 . Referring together with  FIGS. 2 and 3 , the magazine  2  is disposed at an end side of the nail track base  1 . The nail track base  1  defines a nail driving track  11 , which is in communication with the magazine  2 . The braking mechanism includes a safety rod  4 , a sliding member  3 , a swing stem  5  and a slope guide plate  6 . The sliding member  3  is slidably received in the magazine  2 . The sliding member  3  extends to the nail driving track  11  and forms a pressing portion  31  at an end thereof. The pressing portion  31  is configured for pressing the nails  7  into the nail driving track  11 . The safety rod  4  is slidably disposed on the nail track base  1 . The swing stem  5  is pivotably mounted on an end side of the sliding member  3 . The swing stem  5  moves together with the sliding member  3 . In addition, the swing stem  5  extends to the nail track and form a braking portion  51  (as shown in  FIG. 5 ). A straight path  50  is formed between the safety rod  4  and the braking portion  50 . The swing stem  5  further includes a protrusion  52  formed on a surface of the braking portion  51 . The guide plate  6  is located at an end of the straight path  50  and is adjacent to the nail track base  1 . The guide plate  6  is configured for guiding the protrusion  52  (as shown in  FIGS. 7   a  and  7   b ) of the swing stem  5  so as to lead the swing stem  5  away from the straight path  50 . The swing stem  5  can moves to the nail track base  1  together with the sliding member  3  till the protrusion  52  falls off the guide plate  6  (as shown in  FIGS. 4 ,  6  and  7   d ). In the present embodiment, the protrusion  52  falls off the guide plate  6  after the pressing portion  31  of the sliding member  3  pushes last nail  71  in the magazine  2  into the nail driving track  11 . As such, the braking portion  51  moves back to the straight path  50  and block the safety rod  4  to move upwardly. The safety rod  4  drives the inner trigger in the nail gun to swing thereby driving the valve stem of a trigger valve to open the trigger valve when the safety rod  4  moves upwardly to a predetermined position. As such, the nail gun starts to shoot nails  7 . 
     In the present embodiment, the nail  7  is a relative thin nail. However, it is to be understood that the nail  7  is not limited to fine nail. In other words, the nail  7  can be also thick nail. 
     The nail track base  1  includes an upper guide plate  12 , a first lower guide plate  13  and a second lower guide plate  14  (as shown in  FIGS. 1 and 3 ). The nail driving track  11  is formed between the upper guide plate  12  and the first, second lower guide plates  13 ,  14 . Two end grooves  121 ,  141  are respectively formed in the upper guide plate  12  and the second lower guide plate  14 . The end grooves  121 ,  141  are opposite to the braking portion  51  and are parallel to the nail driving track  11 . The safety rod  4  is slidably mounted at a side of the upper guide plate  12 . The safety rod  4  includes an ear portion  41  extends into the end grooves  121 ,  141 . An end of the safety rod  4  extends to a position at which the safety rod is capable of pressing the inner trigger of the trigger thereby driving the valve stem in the trigger valve to open the trigger valve. The safety rod  4  also includes a positioning member  42  extends exceeding a nail exit  15  of the nail driving track  11 . The positioning member  42  is configured for pressing on a surface of a workpiece such that the safety rod  4  moves upwardly or downwardly. As such, the ear portion  41  also moves in the end grooves  121 ,  141  upwardly or downwardly. 
     A distance between the braking portion  51  and the ear portion  41  of the safety rod  4  (as shown in  FIG. 3 ) is less than a distance between the pressing portion  31  of the sliding member  3  and the inner sidewall of the nail driving track  11 . In the present embodiment, a length of the braking portion  51  is greater than that of the pressing portion  31  about thickness of two nails  7 . 
     The magazine  2  is connected to an open end of the nail driving track  11  (as shown in  FIGS. 1 through 3 ). In addition, the magazine  2  includes a nail track  21  that is in communication with the nail driving track  11 . The magazine  2  is configured for receiving a number of nails  7  therein. The sliding member  3  is slidably received in the nail track  21 . At least one spring is disposed between the sliding member  3  and an inner sidewall of the nail track  21 . In the present embodiment, there are two springs  22  or the like employed in the nail gun. The springs  22  are capable of driving the sliding member  3  to move to the nail track base  1  such that the sliding member  3  pushes the nails  7  to enter into the nail driving track  11 . The swing stem  5 , the braking portion  51  and the protrusion  52  moves to the nail track base  1  together with the sliding member  3 . A cutaway portion  23  is formed in the magazine  2 . The cutaway portion  23  is adjacent to the guide plate  6  and connects the nail track  21  to the outer space. The braking portion  51  can pass through the cutaway portion  23  when the guide plate  6  guides the protrusion  52  (as shown in  FIGS. 7   b  and  7   c ). 
     A pivot seat  32  (as shown in  FIGS. 1 and 3 ) is formed on a side of the sliding member  3 . The swing stem  5  includes a pivot portion  53  opposite to the braking portion  51  and the protrusion  52 . The pivot portion  53  is pivotably mounted on the pivot seat  32  using a shaft  54 . In addition, a torque spring  55  is telescopically disposed around the shaft  54 , and two ends of the torque spring  55  are fixed to the sliding member  3  and the swing stem  5  respectively such that the swing stem  5  is resiliently and pivotably disposed on the end side of the sliding member  3 . 
     The guide plate  6  is at an end side of the nail track base  1  (as shown in  FIGS. 1 and 3 ). The guide plate  6  includes an outer slope surface  61  and an inner slope surface  64  (as shown in  FIG. 3   a ). The braking portion  51  is opposite to the outer slope surface  61  when received in the nail track  21 . The braking portion  51  is opposite to the inner slop surface  64  when the braking portion  51  is capable of blocking the safety rod  4  (as shown in  FIG. 7   d ). An outer plain surface  62  (as shown in  FIG. 5 ) extends from the outer slope surface  61  in a direction that is parallel to the straight path  50 , and an inner plain surface  63  extends from the inner slope surface  64  in a direction that is parallel to the straight path  50 . The outer slope surface  61  is configured for guiding the protrusion  52  such that when the braking portion  51  moves to the ear portion  41  of the safety rod along the straight path  50 , the braking portion  51  moves away from the straight path  50  (as shown in  FIGS. 7   a  and  7   b ). The outer plain surface  62  is configured for guiding the protrusion  52  from the outer slope surface  61  such that the braking portion  51  keeps away from the straight path  50  (as shown in  FIG. 7   c ). The inner plain surface  63  is configured for guiding the protrusion  52  to the inner slope surface  64  (as shown in  FIG. 7   e ) when the swing stem  5  goes back to its original position along the straight path  50  from a position at which the swing stem  5  blocks the ear portion  41  of the safety rod  4 . The inner slope surface  64  is capable of guiding the protrusion  52  to get across the guide plate  6  so as to reset position of the braking portion  51  (as shown in  FIG. 7   f ). 
     The braking mechanism for nail guns has been discussed above, and the operation procedure of the braking mechanism will be described in detail as follows. 
     Referring to  FIGS. 2 and 3 , the braking portion  51  is away from the guide plate  6  when there are a number of (e.g. more than 10) nails  7  received in the nail track  21  of the magazine  2 . In such conditions, the operator can easily push the positioning member  42  of the safety rod  4  on a surface of an object. The ear portion  41  moves upwardly along the end grooves  121 ,  141 . As a result, the safety rod  4  drives the inner trigger to rise so as to open the trigger valve for hitting nails. 
     Referring to  FIG. 7   a,  the swing stem  5  is near to the nail track base  1  and the protrusion  52  is in contact with the outer slope surface  61  when there are a few of (e.g. less than 10) nails in the nail track  21  and the nail driving track  11 . The outer slope surface  61  guides the protrusion  52  such that the swing stem  5  is capable of overcome the elastic force applied by the torque spring  55 . The protrusion  52  moves along the outer slope surface  61  and the outer plain surface  62  (as shown in  FIGS. 7   b  and  7   c ) such that the braking portion  51  moves away from the straight path  50 . In such conditions, the operator can still push the safety rod  4  to move upwardly to press the trigger valve. 
     Referring to  FIGS. 7   c  and  7   d,  the pressing portion  31  of the sliding member  3  enters into the nail driving track  11  and is in contact with the inner sidewall of the nail driving track  11  when the last nail  71  in the nail track  21  and the nail driving track  11  is shot into the object. The sliding member  3  and the swing stem  5  moves at a distance of the thickness of the nail  71 . The protrusion  52  moves away from the outer plain surface  62  of the guide plate  6 . Simultaneously, the torque spring  55  drives the swing stem to reset its position. The braking portion  51  moves back to the straight path  50  and enters into the end grooves  121 ,  141 . As a result, the braking portion  51  blocks the ear portion  41  of the safety rod  4  (as shown in  FIGS. 4 and 6 ). Because of the distance between the braking portion  51  and the ear portion  41  is less than the distance between the pressing portion  31  and the inner sidewall of the nail driving track  11 , the braking portion  51  on the straight path  50  is capable of blocking the ear portion  41  using at least an area having a width that equals to a thickness of a nail  7 . In the present embodiment, as shown  FIG. 3 , the braking portion  51  blocks the ear portion  41  using an area having about a width about two times than the thickness of the nails  7 . The safety rod  4  can&#39;t move upwardly when the braking portion  51  blocks the ear portion  41 . Therefore, the operator can&#39;t open the trigger valve to shoot. 
     If the operator want to reload nails  7  in the nail track, the sliding member  3  must be firstly pushed back into the nail track  21  of the magazine  2  such that there is adequate space for receiving nails  7 . The sliding member  3  will bring the swing stem  5  into the nail track together (as shown in  FIG. 7   e ). The braking portion  51  moves back to its original position along the straight path  50  from a position in the end grooves  121 ,  141  at which the braking portion  51  is capable of blocking the ear portion  41 . The inner plain surface  63  guides the protrusion  52  to the inner slope surface  64 . The inner slope surface  64  helps the swing stem  5  to overcome the elastic force applied by the torque spring  55  and moves along the inner slope surface  64 . Finally, the protrusion  52  get across the guide plate  6  (as shown in  FIG. 7   f ). Simultaneously, the torque spring  55  drives the swing stem  5  to reset its position (as shown in  FIG. 7   g ) such that the braking portion moves back into the nail track  21  of the magazine  2 . In such conditions, the operator can open the trigger valve again by pushing the safety rod to move upwardly and shoot nails  7  received in the nail track  21 . 
     It is believed the present braking mechanism for nail guns has been fully disclosed. In the present braking mechanism, the braking portion  51  can be guided by the guide plate  6  and moves along a curved path to a position at which the braking portion  51  is capable of blocking the ear portion  41  of the safety rod  4 . Finally, the braking portion  51  blocks the ear portion  41  using an area having a width that greater than a thickness of a nail. As such, the area the braking portion  51  used to block the ear portion  41  of the safety rod  4  is increased; a stability of braking action of the nail gun when there is no nail in the nail track is improved. 
     In addition, the protrusion  52  can also moves away from the guide plate  6  when there are a few of nails in the nail track  21 . In such conditions, the distance between the protrusion  52  and the guide plate  6  or the distance between the braking portion  51  and the ear portion  41  must to be changed according to practical application. The other parts may employ similar or same structure. 
     The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including configurations ways of the recessed portions and materials and/or designs of the attaching structures. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.