Patent Abstract:
The present invention includes a USB3 device with solderless USB3 connector interfaces, which comprises: a USB3 device main body that houses a carrier body made of rigid material; four interface pins in the outer row that conform to the USB2.0 standard; five interface pins in the inner row that conform to the USB3.0 standard; and a substrate and electronic circuitry; and a USB3 device sub-body that houses: a carrier body made of rigid material; and five interface pins that conform to the USB3.0 standard wherein each interface pin has an upper convex part and a lower concave part; the upper convex part and the lower concave part forms a spring coil pin; and the spring coil pin can withstand multiple times of compression; a top casing; a bottom casing; and a case assembly.

Full Description:
FIELD OF THE INVENTION 
     The present invention relates generally to computing devices and more particularly to a USB device utilized with such computing devices. 
     BACKGROUND OF THE INVENTION 
     The USB host and device are ubiquitous in computing devices including PC, Notebook, Server, Tablet PC, smart TV, media player, gaming machine and peripheral devices. USB3.0 (USB3) interface standard is introduced as the successor to the ever successful USB2.0 (USB2) interface standard. USB3 is aimed to deliver 10 times the performance while maintaining the backward compatibility with USB2. A USB3 device connector traditionally has a total of nine external interface pins, with one row of four and one row of five pins, connecting to a USB3 device through surface mount technology (SMT) or through hole technology. The physical dimension of the USB3 device connector therefore adds length to the size of the USB3 device. If the USB3 device can extend the body of the USB3 device to where the front edge of the USB3 device connector is and achieve the functionality of the USB3 device connector in its main body, it not only eliminates the need for a physical USB3 device connector and saves cost, but also accommodates more real estate or space for the circuitry inside the USB3 device. The challenge lies in how to effectively achieve the functionality of a USB3 device connector in the main body of the USB device. 
     The USB3 host connector introduces five more pins in addition to the original four pins of USB2 host connector. Most USB3 devices require a USB3 device connector that is soldered to a substrate or a PCB in order to securely mate to the USB3 host connector or the USB2 host connector. The two rows of four pins and five pins in the USB3 device connector are mated to the two rows of four pins and five pins correspondingly, in the USB3 host connector. In the case of the USB2 host connector, only the outer row of 4 pins is used in the USB3 device connection to connect. In the situation where the USB3 flash storage device is pre-fabricated in the molding process, the additional reflow soldering process of the USB3 device connector not only complicates the manufacturing but also introduces a low yield to the flash storage in the pre-fabricated USB device. 
     It is therefore advantageous to come up with a solderless USB3 connector and apparatus for the USB device to eliminate the soldering reflow, simplify the manufacturing process and to increase the yield of the USB3 device. 
     The physical difference between USB2 and USB3 host connectors is depicted in  FIGS. 1A and 1B . The cross section view of one of the pins  13  of the USB2 host connector  111  is shown in  FIG. 1A . The cross section view of one of the pins  103 , of the USB3 host connector  113  is shown in  FIG. 1B . A USB2 device connector  112  may be plugged into a USB2 host connector  111  or a USB3 host connector  113 . Likewise, a USB3 device connector  114  may be plugged into a USB2 host connector  111  or a USB3 host connector  113 . 
     As shown in  FIG. 1A , a USB2 host connector  111  has a top casing  10  and a bottom casing  11 . It also has a main body  12  that houses the four interface pins (not shown). One of the pins  13  in the USB2 host connector  111  is shown in a cross section view. The pin  13  is retractable and will recede upward into the USB2 host main body  12  when the main body  17  of the USB2 device is plugged in. A USB2 device connector  112  has a top casing  14 , a bottom casing  15 , a main body  17 , an optional stopper  18  and four interface pins (not shown). One of the pins  16  in the USB2 device connector  112  is shown in a cross section view. The pin  16  will not recede when the USB2 device connector  112  is plugged into the USB2 host connector  111 . Its counterpart pin  13  in USB2 host connector  111  will recede and connect to pin  16  when the USB2 device connector  112  is fully plugged into the USB2 host connector  111 . 
     As shown in  FIG. 1B , a USB3 host connector  113  has a top casing  100  and a bottom casing  101 . It also has a main body  102  that houses the four interface pins (not shown) in the inner row and five interface pins (not shown) in the outer row. One of the pins  103  on the inner row is shown in a cross section view. One of the pins  110  on the outer row is also shown in a cross section view. The pin  103  is retractable and will recede upward into the USB3 host main body  102  when the USB3 device connector  114  is fully plugged in. 
     A USB3 device connector  114  has a top casing  104 , a bottom casing  105 , a main body  107 , an optional stopper  108  and four interface pins (not shown) in the outer row and five interface pins (not shown) in the inner row. One of the pins  106  in the USB3 device connector  114  is shown in a cross section view. The pin  106  will not recede when the USB3 device connector  114  is plugged into the USB3 host connector  113 . Its counterpart  103  on USB3 host connector  113  will recede and connect to pin  106  when the USB3 device connector  114  is fully plugged into the USB3 host connector  113 . One of the pins  109  in the USB3 device connector  114  is shown in a cross section view. The pin  110  in the USB3 host connector  113  will not recede when the USB3 device connector  114  is plugged into the USB3 host connector  113 . Its counterpart pin  109  in the USB3 device connector  114  will recede and connect to pin  110  when the USB3 device connector  114  is fully plugged into the USB3 host connector  113 . 
     When the USB3 device connector  114  is fully plugged into the USB2 host connector  111 , the pin  106  of the USB3 device connector  114  is connected to the pin  13  of the USB2 host connector  111 . The pin  109  in the USB3 device connector  114  will recede and will not make contact with any other pin in the USB2 host connector  111 . 
     As shown in  FIG. 2A ,  FIG. 2B  and  FIG. 20 , a USB3 host connector  113  has a top casing  100  and a bottom casing  101 . It also has a main body  102  that houses the four interface pins (not shown) in the inner row and five interface pins (not shown) in the outer row. One of the pins  103  in the inner row is shown in a cross section view. One of the pins  110  in the outer row is shown in a cross section view. The pin  103  is retractable and will recede upward into the USB3 host main body  102  when the main body  107  of the USB3 device is plugged in. 
       FIG. 2A  is a connection that tries to address the challenge of effectively achieving the functionality of USB device connector in a main body of the USB device. As in  FIG. 2A , a USB3 device  220  has a top casing  24 , a bottom casing  25 , a main body  27 , and a surface mountable sub-body  21 . The main body  27  and the sub-body  21  are connected through surface mount technology. 
     The main body  27  houses four interface pins (not shown) in the first row and five interface pins (not shown) in the fourth. Two of the pins  26  (in the first row) and  23  (in the fourth row) on the USB3 device main body  27  are shown in a cross section view. 
     The surface mountable sub-body  21  houses five interface pins (not shown) in the second row and five interface pins (not shown) in the third row. The second row pins and the third row pins are connected in pairs internally inside the sub-body  21 . Two of the pins  20  (in the second row) and  22  (in the third row) in the USB3 sub-body  21  are shown in a cross section view. Pin  20  and pin  22  are connected internally inside USB3 sub-body  21 . 
     The pin  26  will not recede when the USB3 device  220  is plugged into the USB3 host connector  113 . Its counterpart  103  in USB3 host connector  113  will recede and connect to pin  26  when the USB3 device  220  is fully plugged into the USB3 host connector  113 . 
     The pin  110  in USB3 host connector  113  will not recede when the USB3 device  220  is plugged into the USB3 host connector  113 . Its counterpart pin  20  on USB3 sub-body  21  will also not recede but will also connect to pin  110  when the USB3 device  220  is fully plugged into the USB3 host connector  113 . The reason pin  20  will not recede is that the sub-body  21  and the main body  27  are two separate rigid pieces. There is no room for pin  20  to recede when the USB3 device  220  is plugged into the USB3 host connector  113 . 
     This embodiment achieves the benefits of eliminating an external USB3 device connector and accommodates more real estate or space for the circuitry inside the USB3 device. But it still requires soldering of the USB3 device sub-body  21  to the main body  27 . And because the pin  20  would not recede after the USB3 device  220  is plugged into the USB3 host connector  113 , it sustains stress to the structure of the pin. The impedance of the contact between pin  20  in USB3 device  220  and pin  110  in USB3 host connector starts to change as time progressing. The contact eventually becomes unstable and unreliable. 
     The embodiment as shown in  FIG. 2B , intends to address the same challenge as above. It not only eliminates the need for a physical USB3 device connector and saves cost but also accommodates more real estate or space for the circuitry inside the USB3 device. 
     As shown in  FIG. 2B , a USB3 device  221  has a top casing  204 , a bottom casing  205 , a main body  207 , and a detachable sub-body  201 . The main body  207  and the detachable sub-body  201  are connected through forced contact between five pairs of pins. One pin  200  of the pair is from the sub-body while another pin  203  is from the main body. Pin  200  is connected to pin  202  internally inside sub-body  201 . No soldering between the two pins,  200  and  203 , is required. 
     The main body  207  houses four interface pins (not shown) in the first row and five interface pins (not shown) in the fourth row. Two of the pins  206  (in the first row) and  203  (in the third row) in the USB3 main body  207  are shown in a cross section view. 
     The detachable sub-body  201  houses five interface pins (not shown) in the second row and five interface pins (not shown) in the third row. The second row pins and the third row pins are connected in pairs internally inside the sub-body  201 . Two of the pins  200  (in the second row) and  202  (in the fourth row) in the USB3 sub-body  201  are shown in a cross section view. Pin  200  and pin  202  are connected internally inside USB3 sub-body  201 . 
     The pin  206  will not recede when the USB3 device  221  is plugged into the USB3 host connector  113 . Its counterpart  103  in USB3 host connector  113  will recede and will connect to pin  206  when the USB3 device  221  is fully plugged into the USB3 host connector  113 . 
     The pin  110  in USB3 host connector  113  will not recede when the USB3 device  221  is plugged into the USB3 host connector  113 . Its counterpart pin  200  on USB3 sub-body  201  also will not recede but will still connect to pin  110  when the USB3 device  221  is fully plugged into the USB3 host connector  113 . The reason pin  200  will not recede is that the sub-body  201  and the main body  207  are two separate rigid pieces. There is no room for pin  200  to recede when the USB3 device  221  is plugged into the USB3 host connector  113 . 
     This prior art achieves the benefits of eliminating an external USB3 device connector and accommodates more real estate or space for the circuitry inside the USB3 device. It also eliminates soldering of the USB3 device sub-body  201  to the main body  207 . But because the pin  200  would not recede after the USB3 device  221  is plugged into the USB3 host connector  113 , it sustains stress to the structure of the pin. The impedance of the contact between pin  200  in USB3 device  221  and pin  110  in USB3 host connector starts to change as time progresses. The contact eventually becomes unstable and unreliable. The contact between pin  202  in the USB3 sub-body and pin  203  in the USB3 main body would also become unstable and unreliable, due to the constant stress pressing between the pair of pins. The contact may also be weakened by the lever effect asserted by the force pressing against pin  200  when the USB3 device  221  is plugged into the USB3 host connector  113 . 
     Another prior art, as shown in  FIG. 2C , is a derivative of the prior art in  FIG. 2B . Again it not only eliminates the need for a physical USB3 device connector and saves cost but also accommodates more real estate or space for the circuitry inside the USB3 device. It also has a detachable sub-body  211  that requires no soldering to the main body  217 . By eliminating the third row pins in the sub-body  211 , it further saves cost compared with that of the prior art in shown in  FIG. 2B . 
     As shown in  FIG. 20 , a USB3 device  222  has a top casing  214 , a bottom casing  215 , a main body  217 , and a detachable sub-body  211 . The main body  217  and the detachable sub-body  211  are connected through forced contact between five pairs of pins. One pin  210  of the pair is from the sub-body  211  while another pin  213  is from the main body  217 . 
     The main body  217  houses four interface pins (not shown) in the first row and five interface pins (not shown) in the fourth row. Two of the pins  216  (in the first row) and  213  (in the third row) on the USB3 main body  217  are shown in a cross section view. 
     The detachable sub-body  211  houses five interface pins (not shown) in the second row. One of the pins  210  (in the second row) on the USB3 sub-body  211  is shown in a cross section view. 
     The pin  216  will not recede when the USB3 device  222  is plugged into the USB3 host connector  113 . Its counterpart  103  in USB3 host connector  113  will recede and connect to pin  216  when the USB3 device  222  is fully plugged into the USB3 host connector  113 . 
     The pin  110  in USB3 host connector  113  will not recede when the USB3 device  222  is plugged into the USB3 host connector  113 . Its counterpart pin  210  on USB3 sub-body  211  also will not recede but will still connect to pin  110  when the USB3 device  222  is fully plugged into the USB3 host connector  113 . The reason pin  210  will not recede is that the sub-body  211  and the main body  217  are two separate rigid pieces. There is no room for pin  210  to recede when the USB3 device  222  is plugged into the USB3 host connector  113 . 
     This embodiment achieves the benefits of eliminating an external USB3 device connector and accommodates more real estate or space for the circuitry inside the USB3 device. It also eliminates soldering of the USB3 device sub-body  211  to the main body  217 . But because the pin  210  would not recede after the USB3 device  222  is plugged into the USB3 host connector  113 , it sustains stress to the structure of the pin. The impedance of the contact between pin  210  in USB3 device  222  and pin  110  in USB3 host connector starts to change as time progresses. The contact eventually becomes unstable and unreliable. The contact between pin  210  in the USB3 sub-body and pin  213  in the USB3 main body would also become unstable and unreliable due to the constant stress pressing between the pair of pins. 
     Accordingly, what is desired is to provide a system and method that overcomes the above issues. The present invention addresses such a need. 
     SUMMARY OF THE INVENTION 
     A first objective of the invention is to achieve the benefits of eliminating an external USB3 device connector and to accommodate more real estate or space for the circuitry inside the USB3 device. 
     A second objective is make the manufacturing process simple and to save cost by eliminating soldering of the USB3 device sub-body to the main body. 
     A third objective is to make the contact mechanism between the USB3 host connector and the USB3 device simple and therefore effectively result in saving the USB3 device cost. 
     A fourth objective of the invention is to reduce or eliminate the constant stress on any contact pins between the USB3 device and the USB3 host connector and therefore extend the reliability of the device and host connector. 
     The present invention includes a USB3 device with solderless USB3 connector interfaces, which comprises: a USB3 device main body that houses a carrier body made of rigid material; four interface pins in the outer row that conform to the USB2.0 standard; five interface pins in the inner row that conform to the USB3.0 standard; and a substrate and electronic circuitry; and a USB3 device sub-body that houses: a carrier body made of rigid material; and five interface pins that conform to the USB3.0 standard wherein each interface pin has an upper convex part and a lower concave part; the upper convex part and the lower concave part forms a spring coil pin; and the spring coil pin can withstand multiple times of compression; a top casing; a bottom casing; and a case assembly. 
     Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  illustrate a first conventional embodiment of USB2.0 and USB3.0 host connectors and devices (cross section view). 
         FIGS. 2A-2C  illustrate a second, third and fourth conventional embodiment of USB3.0 host connectors and devices (cross section view). 
         FIGS. 3A-3C  illustrate a USB3.0 host connector and a USB3.0 device with convex and concave parts in a spring coil pin (cross section view) in accordance with the present invention. 
         FIGS. 4A-4C  illustrate a USB2.0 host connector and a USB3.0 device with convex and concave parts in a spring coil pin (cross section view) in accordance with the present invention. 
         FIGS. 5A-5C  illustrate a USB3.0 host connector and USB3.0 device with groove on main body (cross section view) in accordance with the present invention. 
         FIGS. 6A-6C  illustrate a USB2.0 host connector and a USB3.0 device with groove on main body (cross section view) in accordance with the present invention. 
         FIGS. 7A-7C  illustrate a USB3.0 host connector and a USB3.0 device with convex head pin and concave part in a spring coil pin (cross section view) in accordance with the present invention. 
         FIGS. 8A-8C  illustrate a USB2.0 host connector and a USB3.0 device with convex head pin and concave part in a spring coil pin (cross section view) in accordance with the present invention. 
         FIGS. 9A-9C  illustrate a USB3.0 host connector and a USB3.0 device with convex part and concave contact tip in a spring coil pin (cross section view) in accordance with the present invention. 
         FIGS. 10A-10C  illustrate a USB2.0 host connector and a USB3.0 device with convex part and concave contact tip in a spring coil pin (cross section view) in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates generally to computing devices and more particularly to USB devices utilized with such computing devices. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein. 
     As shown in  FIGS. 3A-3C , a first objective of the invention is to achieve the benefits of eliminating an external USB3 device connector and accommodate more real estate or space for the circuitry inside the USB3 device. A second objective is to make the manufacturing process simple and to save cost by eliminating soldering of the USB3 device sub-body  31  to the main body  37 . A third objective is to make the contact mechanism between the USB3 host connector and the USB3 device simple and to effectively result in saving the USB3 device cost. A fourth objective of the invention is to reduce or eliminate the constant stress on any contact pins between the USB3 device and the USB3 host connector, thereby extending the reliability of the device and host connector. 
     As shown in  FIGS. 3A-3C  and  FIGS. 4A-4C , a USB3 device  300  has a top casing  34 , a bottom casing  35 , a main body  37 , and a detachable sub-body  31 . The detachable sub-body  31  is stacked on top of the main body  37 . 
     The main body  37  houses four interface pins (not shown) in the first row and five interface pins (not shown) in the fourth row. Two of the pins  36  (in the first row) and  33  (in the third row) on the USB3 main body  37  are shown in a cross section view. 
     The detachable sub-body  31  houses five interface pins (not shown) in the second row. One of the pins  30  (in the second row) on the USB3 sub-body  31  is shown in a cross section view. 
     The pin  36  will not recede when the USB3 device  300  is plugged into the USB3 host connector  113 . Its counterpart  103  in USB3 host connector  113  will recede and connect to pin  36  when the USB3 device  300  is fully plugged into the USB3 host connector  113 . 
     The pin  110  in USB3 host connector  113  will not recede when the USB3 device  300  is plugged into the USB3 host connector  113 . Its counterpart pin  30  on USB3 sub-body  31  will recede and connect to pin  110  in the USB3 host connector  113  when the USB3 device  300  is fully plugged into the USB3 host connector  113 . The reason pin  30  will recede is that pin  30  has a spring coil effect and can be compressed when pressed by the USB3 host connector  113 , as shown in  FIGS. 3A-3C . There is also room for pin  30  to recede downward and touch pin  33 , when the USB3 device  300  is plugged into the USB3 host connector  113 . 
     By implementing the first row of four pins and the third row of five pins in the USB3 device  300 , the invention achieves the first objective of eliminating an external USB3 device connector and accommodates more real estate or space for the circuitry inside the USB3 device. By introducing the stacked sub-body  31  on top of the main body  37  in the USB3 device, it also eliminates soldering of the USB3 device sub-body  31  to the main body  37  and achieves the second objective of the invention. 
     Pin  30  on the USB3 device sub-body  31  serves the purpose of connecting between the pin  33  (in the third row) of USB3 device main body  37  and pin  110  in the outer row of USB3 host connector  113 . As shown in  FIG. 3A , before the USB3 device  300  is plugged into the USB3 host connector  113 , pin  30  is free of stress and makes no contact to either pin  33  or pin  110 . When the front edge of USB3 device main body  37  starts touching pin  103  in the USB3 host connector, the pin  103  starts receding into the USB3 host connector main body  102 , as shown in  FIG. 3B . As soon as pin  30  touches the front edge of the USB3 host connector main body  102 , the upper convex part of pin  30  is compressed downward. The insertion force, as the USB3 device  300  traveling inward inside the USB3 host connector  113 , continues to compress the lower part of pin  30 . It forces the pin  30  to touch down on pin  33  of the main body  37  of the USB3 device  300  as is shown in  FIG. 3C . The upper convex part and the lower concave part of the pin  30  serve as a spring coil to withstand the compression resulting from the insertion of USB3 device  300  into the USB3 host connector  113 . As soon as the USB3 device  300  is unplugged from the USB3 host connector  113 , the compressed spring coil in pin  30  is released and rebounds back to its original state. The simplicity in design in the upper convex part and the lower concave part of the pin  30  achieves the third objective of this invention by making the contact mechanism between the USB3 host connector  113  and the USB3 device  300  simple, effectively resulting in saving the USB3 device cost. 
     Before the insertion or after unplugging of the USB3 device  300  into/from the USB3 host connector  113 , the upper convex part and the lower concave part of the pin  30  remain free and do not touch any other part of the USB3 device  300  or USB3 host connector  113 . The spring coil design of the pin  30  is able to compress and rebound to its original state without incurring constant stress on any other part of the USB3 device  300  or USB3 host connector  113 . It therefore achieves the fourth objective of this invention by reducing or eliminating the constant stress on any contact pins between the USB3 device and the USB3 host connector, thereby extending the reliability of the device and host connector. 
       FIGS. 4A-4C  depict the scenario of how a USB3 device  300  is plugged into a USB2 host connector  111 . The difference between a USB3 host connector  113  and a USB2 host connector  111  lies in the fact that a USB2 host connector does not have the additional five pins in the outer row (not shown). The cross section view of the USB2 host connector  111  is show in  FIGS. 4A-4C . Note that a USB2 host connector has less room for the pin  30  in a USB3 device  300  to compress once the USB3 device  300  is fully plugged into the USB2 host connector  111 . 
     As shown in  FIGS. 5A-5C  and  FIGS. 6A-6C , a USB3 device  500  has a top casing  54 , a bottom casing  55 , a main body  57 , and a detachable sub-body  51 . The main body  57  and the detachable sub-body  51  are stacked together. 
     The main body  57  houses four interface pins (not shown) in the first row and five interface pins (not shown) in the fourth row. Two of the pins  56  (in the first row) and  53  (in the third row) on the USB3 device main body  57  are shown in a cross section view. The groove  58 , in a recess area of the main body  57 , accommodates the five interface pins including pin  53 . 
     The detachable sub-body  51  houses five interface pins (not shown) in the second row. One of the pins  50  (in the second row) on the USB3 device sub-body  51  is shown in a cross section view. The pin  50  has at least an upper convex part and a lower convex part that form a spring coil. 
     In order to let the spring coil formed by the upper convex part and the lower concave part of the pin  50  to have more room to compress and rebound, it may be beneficial to have a groove  58  in the main body  57  of the USB3 device  500 . It will further enhance the fourth objective of this invention by reducing or eliminating the permanent stress on any contact pins between the USB3 device and the USB3 host connector and therefore extending the reliability of the device and host connector. The cross section view of the groove  58  is shown in  FIGS. 5A-5C . 
       FIGS. 6A-6C  depict the scenario of how a USB3 device  500  is plugged into a USB2 host connector  111 . The difference between a USB3 host connector  113  and a USB2 host connector  111  lies in the fact that a USB2 host connector does not have the additional five pins in the outer row (not shown). The cross section view of the USB2 host connector  111  is show in  FIGS. 6A-6C . Note that a USB2 host connector has less room for the pin  50  in a USB3 device  500  to compress once the USB3 device  500  is fully plugged into the USB2 host connector  111 . It is therefore beneficial for the groove  58  in the main body  57  of the USB3 device  500  to have a proper groove depth to accommodate both scenarios in plugging into a USB3 host connector  113  and a USB2 host connector  111 . 
     As shown in  FIGS. 7A-7C  and  FIGS. 8A-8C , a USB3 device  700  has a top casing  74 , a bottom casing  75 , a main body  77 , and a detachable sub-body  71 . The main body  77  and the detachable sub-body  71  are stacked together. 
     The main body  77  houses four interface pins (not shown) in the first row and five interface pins (not shown) in the fourth row. Two of the pins  76  (in the first row) and  73  (in the third row) on the USB3 device main body  77  are shown in cross section view. 
     The detachable sub-body  71  houses five interface pins (not shown) in the second row. One of the pins  70  (in the second row) on the USB3 device sub-body  71  is shown in cross section view. The pin  70  has at least an upper convex part and a lower concave part that form a spring coil. This is an alternative embodiment that has a convex head pin in the upper convex part. 
       FIGS. 8A-8C  depict the scenario of how a USB3 device  700  is plugged into a USB2 host connector  111 . The difference between a USB3 host connector  113  and a USB2 host connector  111  lies in the fact that a USB2 host connector does not have the additional five pins in the outer row (not shown). The cross section view of the USB2 host connector  111  is show in  FIGS. 8A-8C . Note that a USB2 host connector has less room for the pin  70  in a USB3 device  700  to compress once the USB3 device  700  is fully plugged into the USB2 host connector  111 . 
     As shown in  FIGS. 9A-9C  and  FIGS. 10A-10C , a USB3 device  900  has a top casing  94 , a bottom casing  95 , a main body  97 , and a detachable sub-body  91 . The main body  97  and the detachable sub-body  91  are stacked together. 
     The main body  97  houses four interface pins (not shown) in the first row and five interface pins (not shown) in the fourth row. Two of the pins  96  (in the first row) and  93  (in the third row) on the USB3 device main body  97  are shown in cross section view. 
     The detachable sub-body  91  houses five interface pins (not shown) in the second row. One of the pins  90  (in the second row) on the USB3 device sub-body  91  is shown in cross section view. The pin  90  has at least an upper convex part and a lower concave part that form a spring coil. This is an alternative embodiment that has a concave contact tip in the lower concave part. 
       FIGS. 10A-10C  depict the scenario of how a USB3 device  900  is plugged into a USB2 host connector  111 . The difference between a USB3 host connector  113  and a USB2 host connector  111  lies in the fact that a USB2 host connector does not have the additional five pins in the outer row (not shown). The cross section view of the USB2 host connector  111  is show in  FIGS. 10A-10C . Note that a USB2 host connector has less room for the pin  90  in a USB3 device  900  to compress once the USB3 device  900  is fully plugged into the USB2 host connector  111 . 
     Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.

Technology Classification (CPC): 7