Abstract:
A fastener includes a head, a threaded shaft, a latching member, and a flexible washer. The threaded shaft extends from the head. The latching member extends from peripheral of the threaded shaft and adjacent to the head. The washer latches onto the latching member.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to fasteners, and particularly to a screw-type fastener. 
         [0003]    2. Description of Related Art 
         [0004]    On circuit boards, some elements need to be fixed to the circuit boards with screws. However, during installation of the screws, an operator may accidentally scratch the surface of the circuit boards, thus damaging traces on the circuit boards. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, all the views are schematic, and like reference numerals designate corresponding parts throughout the several views. 
           [0006]      FIG. 1  is an exploded, isometric view of an embodiment of a screw. 
           [0007]      FIG. 2  is an assembled view of the screw of  FIG. 1 . 
           [0008]      FIG. 3  is a cross-sectional view of the screw of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    The disclosure, including the accompanying drawing, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
         [0010]    Referring to  FIGS. 1 to 3 , an embodiment of a screw  100  includes a head  10 , a threaded shaft  30  extending from the head  10 , a latching member  20 , and a washer  40 . The washer  40  is made of flexible material, such as polycarbonate or nylon. The head  10 , the latching member  20 , and the threaded shaft  30  are made of metal material, such as steel or iron. 
         [0011]    The head  10  is stepped and includes a first column  12  and a second column  14 . The top surface of the first column  12  defines a drive  16 , such as slotted, Phillips, etc. The second column  14  extends from a bottom of the first column  12 . The diameter of the second column  14  is less than the diameter of the first column  12 . The threaded shaft  30  extends from the center of the bottom of the second column  14 . In other embodiments, the head  10  may comprise just one column. 
         [0012]    The latching member  20  extends from a periphery of the threaded shaft  30  adjacent to the second column  14 . The latching member  20  is also a column, the diameter of the latching member  20  is less than the diameter of the second column  14 . A groove  50  is defined between the latching member  20  and the second column  14 . 
         [0013]    The washer  40  is ring-shaped. An inner sidewall  42  of the washer  40  defines a circular groove  44 . The outer diameter of the washer  40  is substantially equal to the diameter of the second column  14 . The inner diameter of the washer  40  is substantially equal to the diameter of the groove  50 . The diameter of the groove  44  is substantially equal to the diameter of the latching member  20 . Distance between the groove  44  and the top of the washer  40  and a distance between the groove  44  and the bottom of the washer  40  are both substantially equal to the width of the groove  50 . 
         [0014]    Referring to  FIG. 3 , in assembly, the flexible washer  40  is deformed and the latching member  20  is engaged in the groove  44 . When fixing an element on a circuit board using the screw  100 , the flexible washer  40  is sandwiched between the circuit board and the screw head  10 , thereby protecting traces on the circuit board from being scratched during installation of the screw  100 . 
         [0015]    It is to be understood, however, that even though numerous characteristics and advantages of the embodiments have been set forth in the foregoing description, together with details of the structure and function of the embodiments, the disclosure is illustrative only, and changes may be made in details, especially in matters of shape, size, and arrangement of parts within the principles of the embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.