Abstract:
The invention relates to communications technologies and discloses a rotation axis, a digital device and a Universal Serial Bus (USB) device. The rotation axis includes a sleeve, an elastic body, an indented washer, and a movable support. The sleeve includes a lip and a cylinder. The elastic body, the indented washer, and the movable support are configured sequentially around the cylinder with the lip adjacent to the elastic body along the axial direction of the cylinder beginning with the lip. A number of concave indents are configured on one end-surface of the indented washer and distributed on a circle. The end-surface of the indented washer where the concave indents are configured contacts one end-surface of the movable support. A number of protrusions are configured on the end-surface of the movable support to mate the concave indents. In the invention, a rotation axis is constituted by a few parts including a sleeve, an elastic body, an indented washer, and a movable part. Therefore, the rotation axis is characterized by simple structure, small size, low cost, and good reliability.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Chinese Patent Application No. 200920174431.4, filed on Nov. 5, 2009, which is hereby incorporated by reference in its entirety. 
     FIELD OF THE INVENTION 
     The invention relates to communications technologies, and in particular, to a rotation axis and a digital device. 
     BACKGROUND OF THE INVENTION 
     With the continuous development of the communications technologies, the size of digital devices like Universal Serial Bus (USB) devices, data cards, and mobile phones is decreasing. As a result, the requirements for components of the digital devices are becoming more advanced. 
     Currently, to increase the flexibility and ease of use of the digital devices, a component known as a rotation axis is used in many digital devices. The most commonly used rotation axis is a metal rotation axis. 
     At least the following weaknesses exist in the conventional rotation axis described above: the structure of the existing metal rotation axis is complex; the size is large; and the cost is high. 
     The inventors have created the above body of information for the convenience of the reader and expressly disclaim all of the foregoing as prior art; the foregoing is a discussion of problems discovered and/or appreciated by the inventors, and is not an attempt to review or catalog the prior art. 
     SUMMARY OF THE INVENTION 
     Embodiments of the invention simplify the structure of a rotation axis and reduce the size and cost. Embodiments of the invention include a rotation axis, a digital device and a USB device. The technical solution is as follows: 
     A rotation axis including a sleeve, an elastic body, an indented washer and a movable support, wherein: 
     the sleeve includes a lip and a cylinder; 
     the elastic body, the indented washer, and the movable support are positioned sequentially around the cylinder with the lip adjacent to the elastic body along the axial direction of the cylinder beginning with the lip; 
     the surface of the indented washer that contacts the surface of the movable support is configured with a first number of concave indents, wherein the concave indents are distributed in a circle; and 
     the surface of the movable support contacting the indented washer is configured with a second number of protrusions, wherein the protrusions correspond to the concave indents on the surface of the indented washer. 
     A digital device including the rotation axis. 
     A Universal Serial Bus (USB) device including a USB plug, a rotating structure, and a device body, wherein: 
     the USB plug is fixedly connected to the rotating structure; the rotating structure includes a rotating unit; the rotating structure and the device body are connected via the rotating unit; and the rotating structure rotates on a side of the device body through the rotating unit. 
     The technical solution provides the following benefit: 
     A rotation axis is comprised of a few parts including a sleeve, an elastic body, an indented washer, and a movable part. Therefore, the rotation axis is characterized by simple structure, small size, low cost, and good reliability. 
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic drawing illustrating positions of parts of a rotation axis provided according to a first embodiment of the invention; 
         FIG. 2  is another schematic drawing illustrating positions of parts of the rotation axis provided according to the first embodiment of the invention; 
         FIG. 3  is a schematic drawing illustrating positions of parts of a rotation axis provided according to a second embodiment of the invention; 
         FIG. 4  is another schematic drawing illustrating positions of parts of the rotation axis provided according to the second embodiment of the invention; 
         FIG. 5  illustrates an overall structure of the rotation axis provided according to the second embodiment of the invention; 
         FIG. 6  illustrates an overall structure of a data card provided according to a third embodiment of the invention; 
         FIG. 7  illustrates a structure of the data card provided according to the third embodiment of the invention where the rotating USB head of the data card is rotated by 90 degrees; 
         FIG. 8  illustrates a structure of the data card provided according to the third embodiment of the invention where the rotating USB head of the data card is rotated by 270 degrees; 
         FIG. 9  illustrates an inner structure of the data card provided according to the third embodiment of the invention; 
         FIG. 10  illustrates another inner structure of the data card provided according to the third embodiment of the invention; 
         FIG. 11  illustrates an overall structure of a USB connector adapter provided according to a fourth embodiment of the invention; 
         FIG. 12  illustrates an inner structure of the USB connector adapter provided according to the fourth embodiment of the invention; 
         FIG. 13  illustrates a structure of an adapter head USB A-part of the USB connector adapter provided according to the fourth embodiment of the invention; 
         FIG. 14  illustrates a structure of an adapter head USB B-part of the USB connector adapter provided according to the fourth embodiment of the invention; 
         FIG. 15  illustrates a structure of the USB connector adapter provided according to the fourth embodiment of the invention where the adapter head USB A-part is rotated by 90 degrees; and 
         FIG. 16  illustrates a structure of a USB device provided according to a fifth embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     To better explain the purpose, technical solution, and benefits of the invention, the embodiments of the invention will be described in detail with reference to the accompanying drawings. 
     First Embodiment 
       FIG. 1  and  FIG. 2  illustrate a rotation axis provided according to the first embodiment of the invention. The rotation axis includes a sleeve  101 , an elastic body  102 , an indented washer  103 , and a movable support  104 . 
     The sleeve  101  includes a lip  1011  and a cylinder  1012 . 
     The elastic body  102 , indented washer  103 , and movable support  104  are positioned sequentially around the cylinder with the lip adjacent to the elastic body along the axial direction of the cylinder  1012  beginning with the lip  1011 . 
     A number of concave indents  1031  are depressed on one end-surface of the indented washer  103  and distributed in a circle. The end-surface of the indented washer  103  where concave indents  1031  are deposited contacts one end-surface of the movable support  104 . This end-surface of the movable support  104  is configured with a number of protrusions  1041  which correspond to the concave indents  1031 . 
     Further, the rotation axis includes a stop ring  105 . The stop ring  105  is positioned around the cylinder  1012  and located behind the movable support  104  along the axial direction. A stop groove  1051  is present on the stop ring  105 . 
     Accordingly, one end-surface of the movable support  104  is configured with a positioning rod  1043 . The end-surface of the movable support  104  with the positioning rod  1043  contacts the stop ring  105 . 
     Further, the rotation axis includes a positioning support  106  which is positioned around the cylinder  1012  and located behind the stop ring  105  along the axial direction. 
     Further, the positioning support  106  is configured with at least one positioning hole  1061 . 
     Further, the rotation axis includes a locking washer  107  which is positioned around the cylinder  1012  and located behind the positioning support  106  along the axial direction. 
     Further, the elastic body  102 , indented washer  103 , and movable support  104  are configured to have a clearance fit in relation to the cylinder  1012 . 
     The stop ring  105 , positioning support  106 , and locking washer  107  are configured to have an interference fit with the cylinder  1012 . 
     Further, the outer surface of the cylinder  1012  includes several positioning surfaces  1012   b.    
     Accordingly, corresponding positioning surfaces are configured respectively on the inner surfaces of the indented washer  103 , stop ring  105 , positioning support  106 , and locking washer  107  that contact the several positioning surfaces  1012   b  of the cylinder  1012 . These positioning surfaces are referred to as positioning surfaces  103   a , positioning surfaces  105   a , and positioning surfaces  107   a.    
     Further, the elastic body  102  is initially compressed. 
     Further, the middle of the cylinder  1012  is configured with a through-hole  1012   a.    
     Further, the positioning support  104  is configured with at least one positioning hole  1042 . 
     The rotation axis provided according to the embodiment of the invention is applicable to digital devices such as USB devices, data cards, and mobile phones. 
     The rotation axis provided according to the embodiment of the invention is implemented with parts including the sleeve, elastic body, indented washer, and movable support. It is characterized by simple structure, small size, low cost, and good reliability. The interaction between the concave indents, the protrusions, and the elastic body produces a tactile feeling so as to realize the angle of each rotation of the rotation axis. In addition, any rotation angle range can be realized for the rotation axis by setting the angle of the stop groove on the stop ring. Further, by adjusting the length and elasticity coefficient of the elastic body or adjusting the depth of engagement between the concave indents and protrusions, the required maximum torque can be obtained. 
     Second Embodiment 
       FIG. 3 ,  FIG. 4 , and  FIG. 5  illustrate a rotation axis provided according to a second embodiment of the invention. The rotation axis includes a sleeve  201 , an elastic body  202 , an indented washer  203 , a movable support  204 , a stop ring  205 , a positioning support  206 , and a locking washer  207 . 
     The sleeve  201  includes a lip  2011  and a cylinder  2012 . The middle of the cylinder  2012  may be configured with a through-hole  2012   a . For embodiments utilizing wiring, wires can be conveniently led through the through-hole  2012   a.    
     Note the shape of the through-hole  2012   a  may be round, square, or rhombic. In one embodiment of the invention, the through-hole  2012   a  takes on a round shape. In other embodiments of the invention, the through-hole  2012   a  may take on other shapes. The shape of the through-hole  2012   a  is not limited to any one embodiment of the invention. 
     The elastic body  202 , indented washer  203 , movable support  204 , stop ring  205 , positioning support  206  and locking washer  207  are positioned sequentially around the cylinder  2012  of the sleeve  201  from the lip  2011  along the axial direction of the cylinder  2012  beginning with the lip  2011 . 
     An appropriate method may be adopted to configure the elastic body  202 , indented washer  203 , movable support  204 , stop ring  205 , positioning support  206  and locking washer  207  around the cylinder  2012  of the sleeve  201  so as to meet certain conditions. In particular, when the elastic body  202  and indented washer  203  are configured around the cylinder  2012  of the sleeve  201 , the configuration method may enable the elastic body  202  and indented washer  203  to move along the axial direction of the cylinder  2012  but not around the cylinder  2012 ; when the movable support  204  is configured around the cylinder  2012  of the sleeve  201 , the configuration method may enable the movable support  204  to move around the cylinder  2012  but not along the axial direction of the cylinder  2012 ; when the stop ring  205 , positioning supporting  206 , and locking washer  207  are configured around the cylinder  2012  of the sleeve  201 , the configuration method may enable the stop ring  205 , positioning supporting  206 , and locking washer  207  to move neither around the cylinder  2012  nor along the axial direction of the cylinder  2012 . 
     In the embodiment of the invention, the configuration of the parts is as follows: the indented washer  203  is positioned around the cylinder  2012  of the sleeve  201  with a clearance fit, the outer surface of the cylinder  2012  of the sleeve  201  is configured with two positioning surfaces  2012   b  (longitudinally symmetric in the embodiment of the invention), and the two inner surfaces of the indented washer  203  that contact the two positioning surfaces  2012   b  of the cylinder  2012  are configured with two positioning surfaces  203   a , so that the indented washer can move to and fro along the axial direction of the cylinder  2012  but not rotate around the cylinder  2012 . The elastic body  202  is configured around the cylinder  2012  with a clearance fit, with one end of the elastic body  202  fixed to the lip  2011  of the sleeve  201  and the other end of the elastic body  202  fixed to the indented washer  203 , so that the elastic body  202  can move to and fro along the axial direction of the cylinder  2012  together with the indented washer  203  but not rotate around the cylinder  2012 . The movable support  204  is configured around the cylinder  2012  of the sleeve  201  with a clearance fit so that the movable support  204  can rotate around the cylinder  2012  but not move along the axial direction of the cylinder  2012 . The stop ring  205 , positioning support  206  and locking washer  207  are fixed to the cylinder  2012  of the sleeve  201  with interference fits and positioning surfaces (positioning surfaces  205   a , positioning surfaces  206   a , and positioning surfaces  207   a ) are configured on the two inner surfaces of the stop ring  205 , positioning support  206  and locking washer  207  that contact the two positioning surfaces  2012   b  of the cylinder  2012 , so that the stop ring  205 , positioning support  206  and locking washer  207  can be relatively still to the sleeve  201 , that is, the stop ring  205 , positioning support  206  and locking washer  207  will not rotate around the cylinder  2012  or move along the axial direction of the cylinder  2012 . 
     Note the elastic body  202 , indented washer  203 , movable support  204 , stop ring  205 , positioning support  206  and locking washer  207  may be configured around the cylinder  2012  of the sleeve  201  in other methods to meet the above conditions. For example, one positioning surface is configured on each part, or three or four or other numbers of positioning surfaces are configured on each part; or the stop ring  205 , positioning support  206  and locking washer  207  are welded fixedly to the cylinder  2012 . The configuration of the parts is not limited to the method provided in the embodiment of the invention. The configuration can be flexible according to practical conditions. 
     The elastic body  202  is initially compressed to provide a certain pressing force. 
     Specifically, the initial state is the state where the elastic body  202  is originally assembled to the rotation axis. The elastic body  202  may be a spring or other structure that provide an elastic force. 
     The end-surface of the indented washer  203  that contacts the movable support  204  are configured with a number of concave indents  2031 . 
     The concave indents  2031  on the indented washer  203  may be distributed in a circle. The concave indents  2031  may be distributed evenly or not evenly in a circle of a certain diameter. The diameter depends on the size and the practical application of the indented washer  203 . The diameter is not limited here. The indented washer  203  may be a thin slice in a round, square, or rhombic shape with a round hole in the center. The diameter of the round hole is slightly larger than that of the cylinder  2012 , so that the indented washer  203  can be configured around the cylinder  2012  and move to and fro along the axial direction of the cylinder  2012  but not rotate around the cylinder  2012 . In the embodiment of the invention, the indented washer  203  is preferably a round slice with a round hole in the center. 
     Accordingly, the end-surface of the movable support  204  that contacts the indented washer is configured with a number of protrusions  2041  corresponding to the concave indents  2031 . 
     Particularly, when the movable support  204  is rotated around the cylinder  1012 , the protrusions  2041  can be rotated into or out of the concave indents  2031 . Through the interaction of the protrusions  2041 , concave indents  2031 , and elastic force of the elastic body  202 , the elastic body  202  and indented washer  203  can move to and fro along the axial direction of the cylinder  2012 . The number and distribution of the protrusions  2041  may depend on the number and distribution of the concave indents  2031 . Generally, the number of protrusions  2041  is smaller than or equal to the number of concave indents  2031 . For example, if 12 concave indents  2031  are distributed evenly on a circle of a certain diameter with an angle of 30 degrees between each two adjacent concave indents  2031 , 12 protrusions  2041  can be designed accordingly with an angle of 30 degrees between each two adjacent protrusions  2041 , or 4 protrusions  2041  can be designed with an angle of 90 degrees between each two adjacent protrusions  2041 . If the concave indents  2031  on the indented washer  203  are not evenly distributed on a circle of a certain diameter, the number of protrusions  2041  may be 1. 
     In the embodiment of the invention, the protrusions  2041  are rotated into the concave indents  2031  initially; when the protrusions  2041  on the movable support  204  are rotated relatively to the concave indents  2031  on the indented washer  203 , with the interaction of the elastic force provided by the elastic body  202 , the protrusions  2041  are rotated into the concave indents  2031  and rotated out of the concave indents  2031  constantly. That is, the protrusions  2041  and the concave indents  2031  are constantly interlocked and separated and such changes produce a tactile feeling. The angle of each move of the movable support  204  relative to the indented washer  203  (the process where protrusions  2041  are moved out of the concave indents  2031  and moved into the concave indents  2031  again) can be adjusted by changing the number and positions of the concave indents  2031  on a circle of a certain diameter. For example, if the angle between each two adjacent concave indents  2031  is 30 degrees, the angle of each move of the movable support  204  relative to the indented washer  203  is 30 degrees. The angle of each move of the movable support  204  relative to the indented washer  203  may be described as a working range angle. Changing the number and distribution of the concave indents  2031  on the indented washer  203  can adjust the working range angle of the rotation axis. In addition, the torque that enables the protrusions  2041  of the movable support  204  to move completely out of the concave indents  2031  of the indented washer  203  is the maximum torque of the rotation axis. The maximum torque can be controlled by changing the elasticity coefficient of the elastic body  202  and the size of the protrusions  2041  and concave indents  2031 . To help the protrusions  2041  to move into and move out of the concave indents  2031 , the depth of the concave indents  2031  is generally not large and the diameter of the protrusions  2041  is larger than the depth of concave indents  2031 . 
     The movable support  204  may be a thin slice in a round, square, or rhombic shape with a round hole in the center and the diameter of the round hole is larger than the diameter of the cylinder  2012  so that the movable support  204  can be positioned around the cylinder  2012  and can rotate around the cylinder  2012 . In this embodiment of the invention, the movable support  204  is a round slice with a round hole in the center. In addition, when the rotation axis provided according to this embodiment of the invention is applied to other devices, to help the connection with the other devices, the movable support  204  may be configured with at least one positioning hole  2042 . As shown in  FIG. 3  and  FIG. 4 , a pair of positioning holes  2042  are configured on two sides of the movable support  204 . 
     A stop groove  2051  is configured on the stop ring  205  and a positioning rod  2042  is configured on the end-surface of the movable support  204  that contacts the stop ring  205 . 
     When the positioning rod  2042  on the movable support  204  contacts the edge of the stop groove  2051  on the stop ring  205 , the movable support  204  cannot move in the previous moving direction. Thereby, the stop groove  2051  on the stop ring  205  will limit the move of the positioning rod  2042  on the movable support  204  to a certain angle range. That is, the angle of the stop groove  2051  on the stop ring  205  decides the rotation angle range of the movable support  204 . For example, if the angle of the stop groove  2051  on the stop ring  205  is 270 degrees, the rotation angle range of the movable support  204  is from 0 to 270 degrees. 
     Note, the invention can be implemented without a stop ring  205  but, in this case, the movable support  204  can rotate by any angle clockwise or counterclockwise. When a through-hole  2012   a  is configured in the middle of the cylinder  2012  and wires are led through the through-hole  2012   a , the wires will be hinged. 
     At least one positioning hole  2061  is configured on the positioning support  206 . When the rotation axis is applied in another device, the positioning hole  2061  of the positioning support  206  can fasten the entire rotation axis to the other device. 
     Note the fastening of the rotation axis is not limited to the configuration of the positioning hole  2061  but may be implemented in other methods such as a conventional rotation axis, for example, by the use of a positioning bolt or interference fit. The design can be flexible according to the practical conditions. In addition, the invention can still be implemented without a positioning support  206 . In this case, when the rotation axis is applied in another device, the rotation axis is fastened through other parts in the axis, for example, a positioning hole configured on the lip  2011  of the sleeve  201 . 
     The locking washer  207  can compress and configure the elastic body  202 , indented washer  203 , movable support  204 , stop ring  205 , and positioning support  206  around the cylinder  2012  of the sleeve  201  and force the elastic body  202  to be compressed in the initial state to provide an initial pressing force. 
     Note, the invention can still be implemented with no locking washer  207 . For example, the elastic body  202 , indented washer  203 , movable support  204 , stop ring  205 , and positioning support  206  can be compressed around the cylinder  2012  of the sleeve  201  and the end of the cylinder  2012  is turned outward and fixed to the positioning support  206 ; or, after the elastic body  202 , indented washer  203 , movable support  204 , stop ring  205 , and positioning support  206  are compressed around the cylinder  2012  of the sleeve  201 , the stop ring  205  and positioning support  206  are welded to the cylinder  2012 . 
     The working principle of the rotation axis provided according to the embodiment of the invention is as follows: 
     In the initial state, the protrusions  2041  on the movable support  204  are rotated in the concave indents  2031  on the indented washer  203  and the elastic body  202  is compressed to provide an initial pressing force. When the movable support  204  is rotated, the protrusions  2041  on the movable support  204  are rotated out of the concave indents  2031  on the indented washer. In this case, the indented washer  203  is pressed by the protrusions  2041  on the movable support  204  and moves toward the elastic body  202  to compress the elastic body  202 . The elastic body  202  is compressed by a larger force and the elastic force is greater. When the movable support  204  is rotated again, the protrusions  2041  on the movable support  204  are moved into the next concave indents  2031  and the indented washer  203  moves away from the elastic body  202  under the elastic force of the elastic body  202 . Thus, the elastic body  202  is less compressed and the elastic force is weaker. During the rotation of the movable support  204 , as a protrusion  2041  is moved out of a concave indent  2031  and moved into the next concave indent  2031 , the indented washer  203  moves to and fro along the axial direction of the cylinder  2012  and the compression of the elastic body  202  is larger and smaller accordingly. Such changes produce a tactile feeling. When the movable support  204  is rotated so that the positioning rod  2042  contacts the edge of the stop groove  2051  of the stop ring  205 , the rotation of the movable support  204  is stopped and the maximum rotation angle is reached. 
     The material of the rotation axis is not limited and the material may be metal or plastic. The rotation axis may be made through metal stamping or powder metallurgy. The rotation axis is applicable to digital products such as USB flash disks, data cards, and mobile phones. 
     The rotation axis provided according to the embodiment of the invention is implemented with the parts including the sleeve, elastic body, indented washer, and movable support. It is characterized by simple structure, small size, low cost, and good reliability. The interaction between the concave indents, the protrusions, and the elastic body produces a tactile feeling so as to realize the angle of each rotation of the rotation axis. In addition, any rotation angle range can be realized for the rotation axis by setting the angle of the stop groove on the stop ring. Further, by adjusting the length and elasticity coefficient of the elastic body or adjusting the depth of engagement between the concave indents and protrusions, the required maximum torque can be obtained. 
     The invention will be described further with an exemplary embodiment where the rotation axis is applied in a data card. 
     Third Embodiment 
       FIG. 6  to  FIG. 10  illustrate a data card provided according to a third embodiment of the invention. The data card includes a data card rotating USB head  30  and a data card body  40 . 
     The rotating USB head  30  includes a USB connector  301 , a rotation axis  302 , a connecting wire  303 , a USB upper support  304 , and a USB lower support  305 . The rotation axis  302  includes a sleeve  201 , an elastic body  202 , an indented washer  203 , a movable support  204 , a stop ring  205 , a positioning support  206 , and a locking washer  207 . The structures and functions of the parts of the rotation axis  302  are the same as those in the second embodiment and will not be repeated here. The data card body  40  includes a Printed Circuit Board (PCB)  401 , a data card upper shell  402 , and a data card lower shell  403 . 
     The positioning support  206  of the rotation axis  302  is fixed to the data card upper shell  402  so that the positioning support  206  is fastened to the data card body  40 . 
     Particularly, fixing the positioning support  206  to the data card upper shell  402  may include: welding the positioning support  206  to the data card upper shell  402 ; or designing two positioning holes  2061  on the positioning support  206  and fixing the positioning support  206  to the data card upper shell  402  with two screws; or fixing the positioning support  206  to the data card upper shell  402  by various methods provided in a conventional rotation axis. The method is not limited. If the rotation axis  302  does not have a positioning support  206 , the lip  2011  of the sleeve  201  may be fixed to the data card upper shell  402  using a similar method. 
     The movable support  204  of the rotation axis  302  is fixed to the USB lower support  305  so that the movable support  204  is fixed to the rotating USB head  30 . 
     Particularly, a method similar to fixing the positioning support  206  to the data card upper shell  402  may be adopted to fix the movable support  204  to the USB lower support  305 . The method will not be detailed here. 
     The USB connector  301  is connected to one end of the connecting wire  303 . The other end of the connecting wire  303  is led through the through-hole  2012   a  in the cylinder  2012  and connected to the PCB  401 . 
     Particularly, the connecting wire  303  may be connected to the USB connector  301  and the PCB  401  through welding or clamping. The connection mode is not limited. 
     The conduction between the USB connector  301  and the rotation axis  302  is implemented through a conductor and the conduction between the rotation axis  302  and the PCB  401  is achieved through another conductor. 
     Particularly, a conductor such as a metal spring may be used to implement conduction between the rotation axis  302  and the USB connector  301  and between the rotation axis  302  and the PCB  401  so that the rotation axis  302  is grounded. 
     The USB connector  301  is located between the USB upper support  304  and the USB lower support  305 . The USB upper support  304  and the USB lower support  305  are fastened together to protect and fix the USB connector  301 . 
     The working principle of the data card provided according to the embodiment of the invention is as follows: when the rotating USB head  30  is rotated, the movable support  204  of the rotation axis  302  rotates relatively to the indented washer  203  so that the rotating USB head  30  rotates relatively to the data card body  40 . With the tactile feeling, working range angle and maximum rotation angle provided by the rotation axis  302 , the rotating USB head  30  rotates relatively to the data card body  40 . 
     With a rotation axis that includes such parts as the sleeve, elastic body, indented washer, and movable support, the data card provided according to the embodiment of the invention can rotate by any angle and be characterized by simple structure, small size, low cost, and good reliability. 
     The invention will be described further with an exemplary embodiment where the rotation axis is applied in a USB connector adapter. 
     Fourth Embodiment 
       FIG. 11  to  FIG. 15  illustrate a USB connector adapter provided according the fourth embodiment of the invention. The USB connector adapter includes an adapter head USB A-part  50  and an adapter head USB B-part  60 . 
     The adapter head USB A-part  50  includes a USB A connector  501 , a USB A upper support  502 , a USB A lower support  503 , a rotation axis  504 , and a connecting wire  505 . The rotation axis  504  includes a sleeve  201 , an elastic body  202 , an indented washer  203 , a movable support  204 , a stop ring  205 , a positioning support  206 , and a locking washer  207 . The structures and functions of the parts of the rotation axis  504  are the same as those in the second embodiment and will not be repeated here. The adapter head USB B-part  60  includes a USB B upper support  601 , a USB B lower support  602  and a USB B connector  603 . 
     The positioning support  206  of the rotation axis  504  is fixed to the USB A lower support  503  so that the positioning support  206  is fixed to the adapter head USB A-part  50 . 
     Particularly, a method similar to fixing the positioning support  206  to the data card upper shell  402  in the third embodiment may be adopted to fix the positioning support  206  to the USB A lower support  503 . 
     The movable support  204  of the rotation axis  504  is fixed to the USB B lower support  602  so that the movable support  204  is fixed to the adapter head USB B-part  60 . 
     Particularly, a method similar to fixing the movable support  204  to the USB lower support  305  in the third embodiment may be adopted to fix the movable support  204  to the USB B lower support  602 . 
     The USB A connector  501  is connected to one end of the connecting wire  505 . The other end of the connecting wire  505  is led through the through-hole  2012   a  in the cylinder  2012  and connected to the USB B connector  603 . 
     Particularly, the connecting wire  505  may be connected to the USB A connector  501  and the USB B connector  603  through welding or clamping. The connection mode is not limited. 
     The USB A connector  501  is located between the USB A upper support  502  and the USB A lower support  503 . The USB A upper support  502  and the USB A lower support  503  are fastened together to protect and fix the USB A connector  501 . 
     The USB B connector  603  is located between the USB B upper support  601  and the USB B lower support  602 . The USB B upper support  601  and the USB B lower support  602  are fastened together to protect and fix the USB B connector  603 . 
     The working principle of the USB connector adapter provided according to the embodiment of the invention is as follows: when the adapter head USB B-part  60  is rotated, the movable support  204  of the rotation axis  504  rotates relative to the indented washer  203  so that the adapter head USB B-part  60  rotates relative to the adapter head USB A-part  50 . With the tactile feeling, working range angle and maximum rotation angle provided by the rotation axis  504 , the adapter head USB B-part  60  rotates relative to the adapter head USB A-part  50 . 
     With a rotation axis that includes such parts as the sleeve, elastic body, indented washer, and movable support, the USB connector adapter provided according to the embodiment of the invention can rotate by any angle and be characterized by simple structure, small size, low cost, and good reliability. 
     Fifth Embodiment 
       FIG. 16  illustrates a USB device provided according to the fifth embodiment of the invention. The USB device includes a USB plug  70 , a rotating structure  80 , and a device body  90 . 
     The USB plug  70  is fixedly connected to the rotating structure  80 . The rotating structure  80  includes a rotating unit  801 . The rotating structure  80  and the device body  90  are connected via the rotating unit  801 . The rotating structure  80  rotates on a side of the device body  90  through the rotating unit  801 . 
     The rotating unit  801  is the same as the rotation axis in the first and second embodiments of the invention. It is understandable that the rotating unit of the USB device in the embodiment of the invention may be a gear driven or spring-driven rotating unit. The rotating unit of the USB device in the embodiment of the invention is not limited. 
     A holding groove  901  is configured on the device body  90 . The USB plug  70  and the rotating structure  80  can be held in the holding groove  901  through rotation to integrate with the device body  90 . 
     With a rotation axis that includes such parts as the sleeve, elastic body, indented washer, and movable support, the USB device provided according to the embodiment of the invention can rotate by any angle and be characterized by simple structure, small size, low cost, and good reliability. 
     It will be appreciated that the foregoing embodiments are merely examples of the inventive principles, and that these illustrate only preferred techniques. It is thus contemplated that other implementations of the invention may differ in detail from foregoing examples. As such, all references to the invention are intended to reference the particular example of the invention being discussed at that point in the description and are not intended to imply any limitation as to the scope of the invention more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the invention entirely unless otherwise indicated. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.