Abstract:
An automatic lock device automatically disengages or forms a lock state of the optical module of a scanner. By plugging and unplugging a power plug on the case of the scanner, a clip departs from or embedded into the optical module. Thus, users can lock or unlock the optical module without other additional operation while transporting the scanner. It avoids possible damages to the optical module.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention relates to an automatic lock device for the optical module of a scanner and, in particular, to a lock device automatically locking/unlocking the optical module triggered by plugging/unplugging the power plug. 
     2. Related Art 
     Due to great advances in the opto-electronic technology, we have digital devices such as scanners, digital cameras, digital video recorders, etc. In particular, scanners have been widely used in paperless office environments because they can quickly covert paper documents into electronic files. 
     In an ordinary scanner, there are at least a case, a cover, an optical module, and a transmission mechanism. The case is provided with a scan window. The cover is pivotally installed on one side of the case. The optical module and the transmission mechanism are installed inside the case. The optical module which is driven by the transmission module is installed on a carrier so that the optical module can have a reciprocal motion within the range of the scan window. Since the optical module is a movable device relative to the scanner, the manufacturer often installs a lock on the optical module or the carrier in order to avoid damages or defocus of the optical module due to transportation. The lock fixes the optical module (carrier) before the scanner is shipped out. The consumer has to remove the lock before the first use. 
     However, even with the clear instruction provided by the scanner manufacturer that tells the user to remove the lock before use, many users still forget this step and start the scanner before removing the lock. This often results in damages to the transmission mechanism or the optical module. 
     To solve this problem, some manufacturers install the lock in the vicinity of the connection port. When the lock fixes the carrier, it blocks the connection port at the same time. The user has to remove the lock in order to connect the cable or power plug to the connection port. This can prevent the user from starting the scanner before removing the lock. However, this method is purely designed for preventing damages during shipping from the manufacturer and when the user first operates the machine. The user may not remember or bother to put on the lock in case he or she needs to move the scanner from one place to another. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, the invention provides an automatic lock device which locks/unlocks the optical module according to the plugging/unplugging action of the power plug. Therefore, it can prevent damages to the optical module, while the user does not need to lock/unlock by other additional operation. 
     The automatic lock device of the invention includes a clip part and an elastic device. The clip part is provided on the case of the scanner and has an embedding part for fixing the optical module. The elastic device is in touch with the case and the clip part. When the power plug of the scanner is inserted into the case, it pushes the clip part to deform the elastic device. The embedding part then departs from the optical module. When the power plug is unplugged from the case, the elastic device provides an elastic force to restore the embedding part back to its original position, thereby fixing the optical module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will become more fully understood from the detailed description given hereinbelow illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1A and 1B  are three-dimensional views of the scanner with an automatic lock device according to the first embodiment; 
         FIGS. 2A and 2B  show how the automatic lock device in the first embodiment actions; 
         FIG. 3  is a three-dimensional view of the automatic lock device according to the second embodiment; 
         FIG. 4A and 4B  are three-dimensional views of the scanner with an automatic lock device according to the third embodiment; 
         FIG. 5A and 5B  are three-dimensional views of the scanner with an automatic lock device according to the fourth embodiment; 
         FIGS. 6A and 6B  show how the automatic lock device in the fourth embodiment actions; and 
         FIG. 7A and 7B  are three-dimensional views of the automatic lock device-according to the fifth embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 1A and 1B , the disclosed automatic lock device is installed on a scanner  500 . The scanner  500  has a case  510  and a power plug  530  that receives a power supply. A power outlet  540  is provided on one side of the case  510  in order for the power plug to receive power. The case  510  is installed with an optical module  520  and other electronic devices for achieving the scanner functions. (To emphasize on the features of the invention, irrelevant electronic devices are not shown in the drawing.) The optical module  520  scans documents. The scanning technique is fairly mature and not the main part of the invention; therefore, we do not describe in further detail herein. 
     The automatic lock device  100  disclosed herein includes a clip part  110  and an elastic device  120 . The clip part  110  is a T-shaped block. It has an L-shaped embedding part  111  and a rotating axis  112  pivotally installed on the case  510 . The embedding part  111  rotates about the rotating axis  112  in the case  510 . The L-shaped embedding part  111  contains a first end  111   a  and a second end  111   b  whose positions correspond to the clipping hole  521  on the optical module  520  and the fixing hole  531  on the power plug  530 , respectively. The first end  111   a  can embed into the clipping hole  521 , while the second end  111   b  can embed into the fixing hole  531 . 
     In the current embodiment, the elastic device  120  is a torsion spring with one end fixed to the rotating axis  112  and with the other end tightly against the case  510 . It provides an elastic force to restore the clipping element  110  back to its original state. 
     Generally speaking, before the power plug  530  of the scanner is plugged into the power outlet  540  to receive power, the optical module  520  is in the standby position. The embedding part  111  of the clipping element  110  is constantly embedded in the clipping hole  521  of the optical module  520 , as constrained by the elastic force of the elastic device  120 . Therefore, the invention can prevent the optical module  520  from departing from its standby position and from being damaged when not in use or during shipping. 
     As shown in  FIG. 2A , when the power plug  530  of the scanner  500  is plugged into the power outlet  540 , it simultaneously pushes the top end of the clipping element  110 , rotating the clipping element  110 . The first end  11   a  of the embedding part  111  is driven to depart from the clipping hole  521  of the optical module  520 . On the other hand, the second end  111   b  of the embedding part  111  embeds into the fixing hole  531  of the power plug  530 . In this position, the optical module  520  is no longer constrained by the clipping element  110  and is in a free motion state. The power plug  530  is also fixed. 
     On the other hand, as shown in  FIG. 2B , if the user wants to move the scanner  500 , he or she only needs to unplug the power plug  530 , and then the elastic device  120  provides an elastic force to rotate the clipping element  110  back to its original position, engaging the first end  11   a  of the embedding part  111  into the clipping hole  521  of the optical module  520 . Therefore, the user does not need to worry about locking and unlocking. The optical module is protected from being out of focus or damaged during transportation. 
     Although the elastic device  120  in this embodiment is a torsion spring installed on the rotating axis, the invention has other embodiments in practice. For example, the elastic device  120  can be a spring or chip installed on the case  510 , as long as it can provide the necessary elastic force to rotate the clipping element  110  to its original position. 
     Moreover, the embedding part  111  of the clipping element  110  has an L-shaped in the present embodiment, but the actual applications are not limited to this. The embedding part  111  may have a Y shape or a T shape, as long as its both ends can achieve the effect of clipping into the clipping hole  521  and the fixing hole  531 . 
     Alternatively, as the second embodiment shown in  FIG. 3 , the embedding part  211  of the clipping element  210  has a wedge shape with a protruding first end  211   a  and a second protruding end  211   b  on its edge. 
     Although the embedding part has two ends to embed into the clipping hole of the optical module or the fixing hole of the power plug, the embedding part nevertheless can have only one end in practice. One needs to provide a corresponding hole on the optical module or the power plug for the single end on the embedding part to engage. 
     In the above-mentioned embodiments, the clipping part has a horizontal rotating motion. However, other rotational embedding means can be applied too. As demonstrated in  FIG. 4A and 4B , the disclosed automatic lock mechanism  400  in a third embodiment is vertically installed on the case  610 , so that the embedding part  411  of the clipping element  410  can be embedded on the top portion of the optical module  620 . 
     In addition to the rotational locking mechanism, the invention can achieve the same effect using an automatic lock device with a linear motion. 
     A fourth embodiment of the invention is shown in  FIG. 5A and 5B . The automatic lock mechanism  300  is comprised of a clipping element  310  and an elastic device  320 . One end of the clipping element  310  has an embedding part  311  protruding downwards (into a hook shape) to match with the clipping hole  721  of the optical module  720 . The elastic device  320  can be a spring or a chip inserted between the top surface of the clipping part  310  and the inner wall of the case  710 . 
     As shown in  FIGS. 6A and 6B , the power plug  730  of the invention has a protruding block  731  for raising or lowering the clipping part  310 . The embedding part  311  thus engages with or departs from the clipping hole  721  of the optical module  720 . 
     Although the above-mentioned embodiments all use an elastic device to provide the necessary elastic force for the clipping part to press against the optical module or the power plug even after the clipping part moves, the same effect can be achieved using other means. For example, one may use special materials or a rotating axis with a special shape so that the clipping element cannot readily move after rotation. One can also apply a damping oil or grease on the surface of the rotating axis. As shown in  FIG. 7A and 7B , the automatic lock device  800  in the fifth embodiment uses a rotating axis  812  with a saw surface. It should be noted that although the above embodiments refer to an optical module as the subject to be locked, the invention can be applied to lock the carrier that carries the optical module too. 
     Certain variations would be apparent to those skilled in the art, which variations are considered within the spirit and scope of the claimed invention.