Patent Publication Number: US-2023160414-A1

Title: Eccentric anti-loosening screw device

Description:
FIELD OF THE INVENTION 
     The invention relates to anti-loosening screws and more particularly to an eccentric anti-loosening screw device and method of manufacturing and installing same. 
     BACKGROUND OF THE INVENTION 
     Typically, a workpiece fastened by a screw or bolt will not become loose if the workpiece is stationary. However, the screw may be loosened if the screw is in a vibration environment because the vibration may transmit to the screw. 
     It is known that great vibration occurs at many applications (e.g., running cars, pumps in us, running motorcycles, construction sites or the like). Taking running high-speed railroad cars as an example, screws of the train may loosen due to vibration. This is not safe. 
     Conventionally, two locking members are fastened together by adhesive. Further, the locking members are threadedly put on a screw. Next, one of the locking member at the farthest point of the object is clockwise rotated. Finally, a positioning pin is driven into a gap between the locking members. As a result, a workpiece is fastened by the locking members. 
     While the conventional art is good, continuing improvements of the art are constantly sought. 
     SUMMARY OF THE INVENTION 
     It is therefore one object of the invention to provide an eccentric anti-loosening screw device comprising a screw and a fastening assembly wherein the screw includes a head and an externally threaded shank formed with the head; and the fastening assembly is threadedly secured onto the externally threaded shank and includes first and second locking members each including a longitudinal threaded hole threadedly secured onto the externally threaded shank, and a surface of curved inclination on an end with the threaded hole passing through; the surface of curved inclination is formed by spirally cutting based on an angle of curved inclination; and the angle of curved inclination is greater than a pitch of the externally threaded shank; and the surface of curved inclination of the first locking member is engaged with that of the second locking member to form a gap therebetween; one of more solder points are used to temporarily fasten the first and second locking members together; a rotation of the first locking member about the second locking member fastens the first and second locking members together, the second locking member is further rotated until the solder points are broken so that an eccentric force is generated for fastening the first and second locking members together. 
     It is another object of the invention to provide a method of manufacturing and installing an eccentric anti-loosening screw device comprising the steps of drilling wherein a hole is drilled through a central portion of an elongated, multi-sided member, and a diameter of the hole is about the same as that of the shank; cutting wherein a middle portion of the multi-sided member is spirally cut to form a surface of curved inclination, an angle of curved inclination is greater than a pitch of the shank to form two locking members; fixing wherein a middle portion the surface of curved inclinations of the locking members are engaged prior to rotating with respect to each other, a gap is formed between the locking members, a plurality of solder points are formed to temporarily fasten the locking members together, and an opening angle of the gap is calculated from a center of a circle; threads forming wherein a thread forming machine is used to form threads on an inner surface of the hole until a threaded hole is formed in each locking member, and the locking members form the fastening assembly which is threadedly secured onto the threaded shank; and installing wherein a screw is screwed through a workpiece to be fastened, the fastening assembly is threadedly put on the shank of the screw, a tool is clockwise rotated to turn a second locking member, the fastening assembly rotates to fasten the workpiece, the tool is clockwise rotated to turn the second locking member until the solder points are broken and the gap is increased, and an eccentric force is generated at a joining surface of a first locking member and the second locking member and it is exerted on the workpiece to fasten them together. 
     The invention has the following advantages and benefits in comparison with the conventional art: 
     Anti-loosening. An angle of curved inclination is greater than a pitch of the threaded shank to provide a reliable fastening. The fastening assembly is used to position a workpiece, then the two locking members are used to fasten the workpiece, and next a tool is used to fasten the curved inclinations which are in turn exert an eccentric force on the locking members. Finally, the workpiece, the screw and the locking members are fastened together. 
     Convenient operation. The threads forming step makes female threads of the locking member to be consistent each other. And in turn, it makes fastening more convenient. The locking members of the fastening assembly are threadedly fastened together. As a result, there is no problem of the locking members being separated. 
     Manufacturing cost reduction. More than two different locking members are required by the conventional art in the fastening. Thus, different molds are required in the manufacturing process. In contrast, the invention uses the same locking members, uses the angle of curved inclination of the locking member, and uses the complying pitch of the threaded shank, thereby achieving the purpose of fastening. A single mold is used in the mass production and thus the manufacturing cost is decreased greatly. 
     The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an eccentric anti-loosening screw device of the invention with a fastened workpiece; 
         FIG.  2    is a perspective view of the locking member; 
         FIG.  3    is a flowchart of a method of manufacturing and installing an eccentric anti-loosening screw device of the invention; 
         FIG.  4    is a perspective view of an elongated, multi-sided member used in the drilling step; 
         FIG.  5    is a perspective view of the elongated, multi-sided member with two locking members being formed initially in the cutting step; 
         FIG.  6    is a perspective vie of the locking member; 
         FIG.  7    is a side elevation in part section of the screw and the two locking members in the final sub-step of the cutting step; 
         FIG.  8    is a perspective view of the two locking members being temporarily fastened together by a plurality of solder points in the fixing step; 
         FIG.  9    is a perspective view of the formed locking member in the final sub-step of the fixing step; 
         FIG.  10    is a perspective view of the two locking members being temporarily fastened together by solder points in the threads forming step; 
         FIG.  11    is a view similar to  FIG.  10    where the gap is increased in the final-sub-step of the threads forming step; 
         FIG.  12    is a side elevation of the workpiece, the screw, the two locking members and a tool used in the installing step; 
         FIG.  13    is a perspective view of  FIG.  12   ; 
         FIG.  14    is a perspective view of the tool; and 
         FIG.  15    is a longitudinal sectional view of the tool. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS.  1  to  2   , an eccentric anti-loosening screw device of the invention comprises a screw  11  and a fastening assembly  12  as discussed in detail below. 
     The screw  11  includes a head  11  and a threaded shank  112  formed with the head  11 . The fastening assembly  12  is threadedly secured onto the shank  112  and includes two locking members  121 . The locking member  121  includes a longitudinal threaded hole  1211  threadedly secured onto the shank  112 , and a surface of curved inclination  121  on one end with the threaded hole  1211  passing through its center. 
     The surface of curved inclination  1212  of one locking member  121  is engaged with that of the other locking member  121  to form a gap  1213  between them. One or more solder points  3  are used to temporarily fasten the locking members  121  together. Next, rotating one locking member  121  about the other locking member  121  until the solder points are broken. An eccentric force is exerted on a workpiece  5  by the fastening assembly  12 . As a result, the workpiece  5  is fastened between the fastening assembly  12  and the head  111  of the screw  11 . 
     An opening angle of the gap  1213  is calculated from a center of a circle. Preferably, the angle is between 0-120 degrees. The locking members  121  can be secured together within this angle range. Further, there is no interlocking in rotation. 
     Preferably, the number of the solder points  3  is at least one. The more of the number of the solder points  3  the fastening of the locking members  121  is more reliable. Thus, more force is required to break the solder points  3 . 
     Referring to  FIG.  3   , a method of manufacturing and installing an eccentric anti-loosening screw device of the invention is illustrated. 
     Referring to  FIG.  4    in conjunction with  FIG.  3   , in a drilling step S 1  a hole is drilled through a central portion of an elongated, multi-sided member  211 . A diameter of the hole is about the same as that of the shank  112 . The number of the sides of the member  211  is four or six. Alternatively, the member  211  is a cylinder. 
     Referring to  FIGS.  5 ,  6  and  7    in conjunction with  FIG.  3   , in a cutting step S 2  a middle portion of the multi-sided member  211  is spirally cut to form a surface of curved inclination  1212 . An angle of curved inclination H is greater than a pitch P of the shank  112  so as to form two locking members  121  (see  FIGS.  5  and  7   ). Alternatively, an edge of the multi-sided member  211  is spirally cut to form a surface of curved inclination  1212  based on the angle of curved inclination. The angle of curved inclination H is greater than the pitch P of the shank  112  so as to form a single locking member  121  (see  FIGS.  6  and  7   ). The cutting of the multi-sided member  211  is done by a linear cutting machine, a cutter, or a laser cutting machine. 
     Referring to  FIGS.  8  and  9    in conjunction with  FIG.  3   , in a fixing step S 3  a middle portion the surface of curved inclinations  1212  of the two locking members  121  are engaged prior to rotating with respect to each other. Thus, a gap  1213  is formed between the locking members  121 . A plurality of solder points  3  are formed by spot soldering to temporarily fasten the locking members  121  together. An opening angle of the gap  1213  is calculated from a center of a circle. Preferably, the angle is between 0-120 degrees. 
     Referring to  FIGS.  10  and  11    in conjunction with  FIG.  3   , in a threads forming step S 4  a thread forming machine is used to form threads on an inner surface of the hole until a threaded hole  121  is formed in each locking member  121 . The two locking members  121  form the fastening assembly  12  which is threadedly secured onto the threaded shank  112 . 
     Referring to  FIGS.  12  and  13    in conjunction with  FIG.  3   , a first locking member  121 A and a second locking member  121 B are provided for clarity of illustration. In an installing step S 5  a screw  11  is screwed through a workpiece  5  to be fastened. Next, the fastening assembly  12  is threadedly put on the shank  112  of the screw  11 . Next, a tool  4  is clockwise rotated to turn the second locking member  121 B. And in turn, the fastening assembly  12  rotates to fasten the workpiece  5 . Next, the tool  4  is clockwise rotated to turn the second locking member  121 B until the solder points  3  are broken and the gap  1213  is increased. An eccentric force is generated at a joining surface of the first locking member  121 A and the second locking member  121 B and it is exerted on the workpiece  5  to fasten them together. 
     In short, for fastening a workpiece  5 , the screw  22  is driven through the workpiece  5 . Next, a tool  4  is used to threadedly put the fastening assembly  12  onto the shank  112 . The tool  4  is used to turn the second locking member  121 B to break the solder points. The gap  1213  between the locking members  121 A and  121 B is increased. An eccentric force is generated at a joining surface of the first locking member  121 A and the second locking member  121 B and it is exerted on the workpiece  5  to fasten them together. 
     Referring to  FIGS.  14  and  15    in conjunction with  FIGS.  12  and  13   , in the installing step S 5  the tool  4  includes a coupling member  41  for attaching to a portable electric tool, a sleeve  42  moveably put on the coupling member  41 , and a plurality of steel balls  43  rotatably disposed on an outer surface of the coupling member  41  for positioning the sleeve  42 . An axial through channel  421  is formed in the sleeve  42  for complementarily receiving the locking member  121 . A depth of the channel  421  is more than a total depth of the two locking members  121 . The tool  4  pushes the sleeve  42  in the installing step S 5  until the two locking members  121  are received in the channel  421 . Further, in a next fastening step the sleeve  42  is pulled until only one locking member  121  is received in the channel  421 . Also, a hole  411  of the coupling member  41  is configured to allow the shank  112  to extend thereinto. 
     The invention has the following advantages and benefits in comparison with the conventional art: 
     Anti-loosening. An angle of curved inclination is greater than a pitch of the threaded shank to provide a reliable fastening. The fastening assembly is used to position a workpiece, then the two locking members are used to fasten the workpiece, and next a tool is used to fasten the curved inclinations which are in turn exert an eccentric force on the locking members. Finally, the workpiece, the screw and the locking members are fastened together. 
     Convenient operation. The threads forming step makes female threads of the locking member to be consistent each other. And in turn, it makes fastening more convenient. The locking members of the fastening assembly are threadedly fastened together. As a result, there is no problem of the locking members being separated. 
     Manufacturing cost reduction. More than two different locking members are required by the conventional art in the fastening. Thus, different molds are required in the manufacturing process. In contrast, the invention uses the same locking members, uses the angle of curved inclination of the locking member, and uses the complying pitch of the threaded shank, thereby achieving the purpose of fastening. A single mold is used in the mass production and thus the manufacturing cost is decreased greatly. 
     While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.