Patent Publication Number: US-2023135213-A1

Title: Fastener, driver bit and punch tool

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Taiwanese Invention Patent Application No. 110140089, filed on Oct. 28, 2021. 
     FIELD 
     The disclosure relates to a fastener, a driver bit and a punch tool, and more particularly to a fastener and a driver bit that are operable to fittingly engage with each other, and a punch tool for forming the fastener. 
     BACKGROUND 
     Referring to  FIG.  1   , a conventional fastener  1  has a recess  11  that is formed in a top surface thereof and that is in the shape of a six-pointed star (i.e., a six-lobe recess). Due to manufacturing tolerance, the recess  11  of the conventional fastener  1  may not fittingly engage with a driver bit. When a user engages a driver bit that is attached to a power tool or a hand tool with the recess  11  of the conventional fastener  1  and turns the driver bit to tighten or loosen the conventional fastener  1 , a torque exerted by the user or by the power tool may not be sufficiently transmitted to the fastener  1 . Furthermore, slippage between the driver bit and the fastener  1  may occur and cause the damage of the inner wall of the recess  11  and the driver bit. It would be hard for the user to further fasten or loose the fastener. An additional tool may be needed to remove the fastener with damaged recess. Therefore, the cost and time consumption for installation would be increased. On the other hand, an outer surface of the conventional fastener  1  may be coated with a corrosion-resistant material so that the conventional fastener can be used in a harsh environment. However, the corrosion-resistant material may accumulate in the recess  11  to adversely affect the engagement between the driver bit and the recess  11  of the conventional fastener  1 . The driver bit would wobble during the installation of the fastener  1  or be even unable to engage with the recess  11  of the conventional fastener  1 —depending on the degree of the accumulation of the corrosion-resistant material. 
     SUMMARY 
     Therefore, an object of the disclosure is to provide a fastener that can alleviate at least one of the drawbacks of the prior art. 
     According to the disclosure, the fastener includes a screw head and a screw shank. The screw head has a top surface, and an inner surrounding surface that is connected to the top surface. The inner surrounding surface defines a recess that is recessed from the top surface. The inner surrounding surface has six curved portions and six driven portions that are disposed about a central axis of the fastener in an alternating arrangement. Each of the driven portions has two opposite ends that are respectively connected to two of the curved portions adjacent to the driven portion. Each of the driven portions has a curved section that is connected to one of the two adjacent curved portions and that has a direction of curvature opposite to that of the one of the two adjacent curved portions, a straight section that extends along a tangent line of an end of the curved section distal from the one of the two adjacent curved portions, and an extension section that is connected between the straight section and the other one of the two adjacent curved portions. The screw shank extends downwardly from the screw head. An outer surrounding surface of the screw shank is formed with a thread that helically extends along the screw shank. 
     Another object of the disclosure is to provide a driver bit that can alleviate at least one of the drawbacks of the prior art. 
     According to the disclosure, the driver bit includes a connecting portion and a driver head. The driver head extends downwardly from the connecting portion. The driver head has six curved portions and six driving portions that are disposed about a central axis of the driver bit in an alternating arrangement. Each of the driving portions has two opposite ends respectively connected to two of the curved portions that are adjacent to the driving portion. Each of the driving portions has a curved section that is connected to one of the two adjacent curved portions and that has a direction of curvature opposite to that of the one of the two adjacent curved portions, a straight section that extends along a tangent line of an end of the curved section distal from the one of the two adjacent curved portions, and an extension section that is connected between the straight section and the other one of the two adjacent curved portions. 
     Another object of the disclosure is to provide a punch tool that can alleviate at least one of the drawbacks of the prior art. 
     According to the disclosure, the punch tool includes a main body and a punch head. The punch head extends downwardly from the main body. The punch head has six curved portions and six convex portions that are disposed about a central axis of the punch tool in an alternating arrangement. Each of the convex portions has two opposite ends respectively connected to two of the curved portions that are adjacent to the convex portion. Each of the convex portions has a curved section that is connected to one of the two adjacent curved portions and that has a direction of curvature opposite to that of the one of the two adjacent curved portions, a straight section that extends along a tangent line of an end of the curved section distal from the one of the two adjacent curved portions, and an extension section that is connected between the straight section and the other one of the two adjacent curved portions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the disclosure will become apparent in the following detailed description of the embodiments with reference to the accompanying drawings, of which: 
         FIG.  1    is a top view illustrating a conventional fastener; 
         FIG.  2    is a top view illustrating an embodiment of the fastener according to the disclosure; 
         FIG.  3    is a perspective view illustrating the fastener; 
         FIG.  4    is a schematic view illustrating a driven portion of the fastener; 
         FIG.  5    is a side view illustrating an embodiment of the driver bit according to the disclosure; 
         FIG.  6    is a fragmentary perspective view illustrating the driver bit and a fastener; 
         FIG.  7    is a schematic view illustrating a driving portion of the driver bit; 
         FIG.  8    is a sectional view illustrating engagement between the driver bit and the fastener; 
         FIG.  9    is a side view illustrating an embodiment of the punch tool according to the disclosure; 
         FIG.  10    is a fragmentary perspective view illustrating the punch tool and a fastener; and 
         FIG.  11    is a schematic view illustrating a convex portion of the punch tool. 
     
    
    
     DETAILED DESCRIPTION 
     Before the disclosure is described in greater detail, it should be noted that where considered appropriate, reference numerals or terminal portions of reference numerals have been repeated among the figures to indicate corresponding or analogous elements, which may optionally have similar characteristics. 
     Referring to  FIGS.  2  to  4   , an embodiment of the fastener  2  according to the disclosure includes a screw head  21 , and a screw shank  22  that integrally extends downwardly from a bottom end of the screw head  21 . The screw head  21  has a top surface  211 , and an inner surrounding surface  212  that is connected to the top surface  211 . The inner surrounding surface  212  defines a recess  214  that is recessed from the top surface  211 . The inner surrounding surface  212  has six curved portions  215  and six driven portions  216  that are disposed about a central axis of the fastener  2  in an alternating arrangement. Each of the driven portions  216  has two opposite ends respectively connected to two of the curved portions  215  that are adjacent to the driven portion  216 . Each of the driven portions  216  has a curved section  217  that is connected to one of the two adjacent curved portions  215  and that has a direction of curvature opposite to that of the one of the two adjacent curved portions  215 , a straight section  218  that extends along a tangent line of an end of the curved section  217  distal from the one of the two adjacent curved portions  215 , and an extension section  219  that is connected between the straight section  218  and the other one of the two adjacent curved portions  215 . The extension section  219  may be configured as a straight surface or a curved surface, so an intersection (A, see  FIG.  4   ) of the extension section  219  and the straight section  218  may be in the form of an acute angle, a right angle, an obtuse angle or a fillet. In the case that the intersection (A) of the extension section  219  and the straight section  218  is in the form of a fillet, stress may be uniformly distributed on the inner surrounding surface  212  when the fastener  2  is driven by a driver bit, so the inner surrounding surface  212  may be prevented from being damaged. An outer surrounding surface of the screw shank  22  is formed with a thread  221  that helically extends along the screw shank  22 . In this embodiment, a radius of curvature of the curved portions  215  is greater than that of the curved sections  217  of the driven portions  216 . In the case that the intersection (A) of the extension section  219  and the straight section  218  is in the form of a fillet, the radius of curvature of the curved sections  217  of the driven portions  216  is greater than a fillet radius of the intersection (A) of the extension section  219  and the straight section  218 . 
     Referring to  FIGS.  5  to  7   , an embodiment of the driver bit  3  according to the disclosure is adapted for driving the fastener  2 , and includes a connecting portion  31 , and a driver head  32  that extends downwardly from the connecting portion  31 . The driver head  32  has six curved portions  321  and six driving portions  322  that are disposed about a central axis of the driver bit  3  in an alternating arrangement. Each of the driving portions  322  has two opposite ends respectively connected to two of the curved portions  321  that are adjacent to the driving portion  322 . Each of the driving portions  322  has a curved section  323  that is connected to one of the two adjacent curved portions  321  and that has a direction of curvature opposite to that of the one of the two adjacent curved portions  321 , a straight section  324  that extends along a tangent line of an end of the curved section  323  distal from the one of the two adjacent curved portions  321 , and an extension section  325  that is connected between the straight section  324  and the other one of the two adjacent curved portions  321 . The extension section  325  may be configured to be straight or curved, so an intersection (B, see  FIG.  7   ) of the extension section  325  and the straight section  324  may be in the form of an acute angle, a right angle, an obtuse angle or a fillet. In this embodiment, a radius of curvature of the curved portions  321  is greater than that of the curved sections  323  of the driving portions  322 . In the case that the intersection (B) of the extension section  325  and the straight section  324  is in the form of a fillet, the radius of curvature of the curved sections  323  of the driving portions  322  is greater than a fillet radius of the intersection (B) of the extension section  325  and the straight section  324 . 
     Referring to  FIGS.  5 ,  6  and  8   , when the driver bit  3  is inserted into the recess  214  of the fastener  2 , the extension sections  325  of the driver bit  3  respectively abut against the extension sections  219  of the fastener  2 . By forming the extension sections  219  and the straight sections  218 , a contact area between the driver bit  3  and the fastener  2  is increased. Although manufacturing tolerance exists in the driver bit  3  and the fastener  2 , the driver bit  3  and the fastener  2  may be able to fittingly engage with each other by the presence of the extension sections  219  and the straight sections  218 . As such, the driver bit  3  and the fastener  2  may not slip relative to each other, so that a torque exerted on the driver bit  3  can be sufficiently transmitted to the fastener  2 , and the driver bit  3  and the inner surrounding surface  212  that defines the recess  214  may be prevented from abrasion and damage. Furthermore, corrosion on damaged portions of the fastener  2  resulting from the environment can be therefore prevented. Since the torque can be sufficiently transmitted from the driver bit  3  to the fastener  2 , when the driver bit  3  is turned by a power tool, electric power can be efficiently used, and electricity consumption can be therefore reduced. Since the driver bit  3  is able to fittingly engage the recess  214  of the fastener  2 , the fastener  2  may not fall off from the driver bit  3  easily. When a user manually turns or uses a power tool to turn the fastener  2  via the driver bit  3 , which is attached to a hand tool or the power tool, with one hand, the fastener  2  need not be held in the other hand of the user. Therefore, the driver bit  3  and the fastener  2  are able to be operated by only one hand, easing the operation, and the driver bit  3  and the fastener  2  would not wobble relative to each other, enhancing the stability during operation. The intersections (A) formed by the extension sections  219  and the straight sections  218  facilitate insertion of the driver bit  3  into the recess  214  of the fastener  2  and positioning between the driver bit  3  and the fastener  2 , and serve to prevent stress concentration and damage during the insertion of the driver bit  3  into the recess  214  of the fastener  2 . In addition, when the fastener  2  is coated with a corrosion-resistant material, residual corrosion-resistant material may be accommodated in spaces formed in the intersections (A), so the residual corrosion-resistant material may not affect the insertion of the driver bit  3  into the recess  214  of the fastener  2 . The drawback of the conventional fastener that the corrosion-resistant material would easily accumulate in the six-lobe recess to affect the engagement between the conventional fastener and a driver bit is alleviated. 
     Referring to  FIGS.  9  to  11   , an embodiment of the punch tool  4  according to the disclosure is adapted for forming the fastener  2 . The punch tool  4  has a main body  41 , and a punch head  42  that extends downwardly from the main body  41  and that is adapted to form the recess  214  of the fastener  2 . The punch head  42  has six curved portions  421  and six convex portions  422  that are disposed about a central axis of the punch tool  4  in an alternating arrangement. Each of the convex portions  422  has two opposite ends respectively connected to two of the curved portions  421  that are adjacent to the convex portion  422 . Each of the convex portions  422  has a curved section  423  that is connected to one of the two adjacent curved portions  421  and that has a direction of curvature opposite to that of the one of the two adjacent curved portions  421 , a straight section  424  that extends along a tangent line of an end of the curved section  423  distal from the one of the two adjacent curved portions  421 , and an extension section  425  that is connected between the straight section  424  and the other one of the two adjacent curved portions  421 . The extension section  425  may be configured to be straight or curved, so an intersection (C, see  FIG.  11   ) of the extension section  425  and the straight section  424  may be in the form of an acute angle, a right angle, an obtuse angle or a fillet. In this embodiment, a radius of curvature of the curved portions  421  is greater than that of the curved sections  423  of the convex portions  422 . In the case that the intersection (C) of the extension section  425  and the straight section  424  is in the form of a fillet, the radius of curvature of the curved sections  423  of the convex portions  422  is greater than a fillet radius of the intersection (C) of the extension section  425  and the straight section  424 . With particular reference to  FIG.  10   , the recess  214  of the fastener  2  is formed by the punch head  42  before the screw shank  22  is threaded to form a helically-extending thread. 
     In summary, by virtue of the extension sections  219  and the straight sections  218 , a contact area between the driver bit  3  and the fastener  2  is increased, and the driver bit  3  and the fastener  2  may be able to fittingly engage with each other. As such, the driver bit  3  and the fastener  2  may not slip relative to each other, so that a torque exerted on the driver bit  3  can be sufficiently transmitted to the fastener  2 , and the driver bit  3  and the inner surrounding surface  212  that defines the recess  214  may not be damaged. Thus, the driver bit  3  and the fastener  2  can be easily operated, and service life of both the driver bit  3  and the fastener  2  can be extended. 
     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 embodiments. 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 are considered the exemplary embodiments, it is understood that this disclosure is not limited to the disclosed embodiments 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.