Abstract:
An encoder device coupled to a roller or “scroll wheel” includes a mechanism to convert a rotating movement of the roller into a reciprocating movement that causes intermittent electrical conduction between two metal contacts so as to output an intermittent electrical signal indicative of roller movement without continuous power consumption.

Description:
FIELD OF THE INVENTION 
   The present invention relates to an encoder, and particularly to an encoder device that includes a mechanism for converting a rotating movement of a roller or “scroll wheel” into a piston-like reciprocating movement that intermittently causes electric conduction between two metal contacts. The mechanism instantly outputs an electrical signal when contact is made, and cuts off the electric conduction when contact is broken so as to save power while still tracking movement of the roller. 
   BACKGROUND OF THE INVENTION 
   Input or output devices having a roller thereon are becoming increasingly popular. The roller is typically arranged to enable a user to scroll a display on a screen. If the roller if depressed, an extra predetermined program or function will be activated, such as logging onto the internet, receiving e-mails, and so forth. Because of the convenience of the roller, manufacturers are rushing to create or to build related structures or methods for practical use. 
   U.S. Pat. No. 5,912,661, U.S. Pat. No. 6,157,369, and U.S. Pat. No. 6,326,949 show conventional encoder devices that utilize a grating wheel and in which a light transmitter and a light detector are located at each side of the grating wheel. The projected light from the transmitter is intermittently blocked by a plurality of slots on the grating wheel that causes the detector to sense the changes in dark and light as to output an intermittent electrical signal. Disadvantages of this arrangement are that the transmitter and detector must be in precise alignment, and the transmitter must emit light continuously even when the grating wheel blocks transmission, so that further movement of the grating wheel can be detected. 
   U.S. Pat. No. 6,198,057 shows an alternative arrangement in which a rotary encoder 2 is coupled with an axle 5 of a roller 4, and a plurality of brushes are rotatably-connected with a corresponding number of contacts to generate an intermittent signal. This arrangement is simpler to assemble than optical encoders, and only a generates and electric signal when contact is made, but still requires relatively precise alignment of contacts and encoder wheel. 
   Finally, U.S. Pat. No. 5,657,051 discloses a switch-like encoder arranged to output intermittent signals following depression of a user&#39;s finger. The structure is easy to build, but the way that the user has to move his finger forward and backward tends not only to cause fatigue over the user&#39;s hand, but also inconvenience in use in comparison with the roller type. 
   SUMMARY OF THE INVENTION 
   The primary object of the present invention is to provide a stable, small size and power-saving encoder device to output an electrical signal. 
   The encoder device combines with a roller with a mechanism for converting the rotating movement of the roller into a piston-like reciprocating movement that intermittently causes electric conduction so as to instantly output an electrical signal whenever the mechanism established contact between two contact elements. 
   The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the present invention. 
       FIG. 2  is another perspective view of  FIG. 1 . 
       FIG. 3  is an exploded perspective view of the present invention. 
       FIG. 4  is another exploded perspective view of  FIG. 3 . 
       FIG. 5A  is a sectional view of the present invention when the roller rotates clockwise. 
       FIG. 5B  is another sectional view of  FIG. 5A  where the roller at a position generating an output signal and the roller keeps rotating clockwise. 
       FIG. 6A  is a sectional view of the present invention when the roller rotates counterclockwise. 
       FIG. 6B  is another sectional view of  FIG. 6A  where the roller at a position generating an output signal and the roller keeps rotating counterclockwise. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention relates to an encoder which includes a roller. Whenever a user rotates the roller, the rotating movement of the roller is converted into a reciprocating movement that intermittently closes a circuit to generate an electrical signal. The electrical signal may be used to control the scrolling of a display on a screen. 
   A preferred embodiment of the present invention includes a depressing unit, a roller, movement-conversion unit, a roller-supporting unit, and an electricity-conducting unit. Referring to  FIG. 1 , a roller  2  can be rotated forward and backward, and further can be depressed forcing a depressing portion  112  of a depressing plate  1  to activate a micro switch  10  located on a circuit board  20  that enables a further program or function to be presented on the screen, such as logging on the internet or opening an email, etc. 
   Referring to  FIG. 2 . the roller  2  is secured to a roller supporter  6  of a roller support unit that includes a flexible structure  61  which has a plurality of curved structures. One end of the structure  61  is fixed on the circuit board  20 , and the other end of the structure  61  is coupled to the roller supporter  6 . As shown in  FIGS. 1 and 2 , when a user depresses the roller  2 , the flexible structure  61  will be deformed at the same time so as to force the depressing portion of a depressing plate  1  to activate the micro switch  10  thereunder. 
     FIGS. 3 and 4  illustrate the relationship between various additional components of the preferred embodiment. An extending axle  111  extends from one side of the depressing plate, and a depressing portion  112  extends from the other side so as to enable activation of the micro switch  10 . The roller  2  has an open side which has an inner-rim with a plurality of roller teeth  21 , and a closed side where a hole  22  is located at a center of the roller  2  allowing penetration of the extending axle  111 . The open side of the roller  2  and the roller support unit provide a space in between to contain the movement conversion unit. 
   The movement-conversion unit includes a slider  3  and a resilient element  4 . The top end of the slider has slider teeth  31  to match with the roller teeth  21 , while the lower end of the slider has a protrusion  32 . The center of the slider  31  has a through-opening  35 , and a recess  34  beneath the slider teeth  31  which contains a resilient element  4  therein. 
   Referring to  FIGS. 3–5A . The roller-supporting unit includes the above-described roller supporter  6 , one side of which includes a flexible structure  61 , which is fixed to circuit board  20  or alternatively to a portion of a housing which contains the present invention. The other side of the roller supporter  6  has a cylindrical wall  63  enclosed within the roller  2 . The top end of the wall  63  has an opening  64  that enables the teeth  31  to be positioned within the opening  64 . When the roller  2  is still, two shoulders  33  of slider  3  constantly contact the inner-rim of the cylindrical wall  63  due to the bias provided by the resilient element  4 , such that the slider teeth  31  constantly protrude from the opening  64 . 
   The cylindrical wall  63  has a hollow axle  65  therein that penetrates the through-hole  35 . When the roller supporter  6  is coupled to the slider  3 , roller  2 , and the depressing plate  1  together, the resilient element  4  presses against the hollow axle  65 , which also fixedly couples to the extending axle  111  of the depressing plate  1 . In practical use, the hollow axle  5  is tightly matched with the extending axle  111  such that the roller  2  and slider  3  can move relative to the roller supporter  6 , while the depressing plate  1  is prevented from rotating together with roller  2 . Alternatively, as shown in  FIG. 4 . rotation of the depressing plate  1  with roller  2  relative to roller supporter  6  is prevented by providing the hollow axle  65  with a groove  66  inside, and the extending axle  111  with a pin  113  thereon. In that case, the pin  113  is tightly coupled to the groove  66  so as to rotatably support the roller  2 , slider  3 , without causing rotation of the depressing plate  1  with the roller  2 . 
   Furthermore, the flexible structure  61  has leading grooves  611 ,  612 ,  613 . The intersection between the leading grooves  611 ,  612 ,  612  and the roller supporter  6  has three corresponding opening  621 ,  622 ,  623 . 
   Referring to  FIGS. 3–5A , the electricity-conducting unit has three contacts  7 ,  8 ,  9 , and a metal plate  5 . A lower section of the metal plate  5  has a ring portion  53 , and a higher section has two projections  51 ,  52 . In addition, the metal plate  5  is fixed within the cylindrical wall  63 . When the roller supporter  6  is coupled to metal plate  5 , resilient element  4 , slider  3 , roller  2  and depressing plate  1 , the contacts  7 ,  8 ,  9  are located within the leading grooves respectively and extend through the openings  621 ,  622 ,  623  toward metal plate  5  such that the contacts  7 ,  8  are located just under the projections  51 ,  52  respectively and the contact  9  is in constant electrical contact with the ring portion  53 . 
   As shown in  FIG. 5A , when a user rotates the roller  2  clockwise, with the roller teeth  21  and slider teeth  31 , the slider  3  will rotate to a certain angle, and then stop turning due to engagement between an outer one of the slider teeth  31  and cylindrical wall  63 . As shown in  FIG. 5B , if the roller  2  keeps turning, the stopped slider  3  will be moved due to the roller teeth  21  gradually pushing the slider teeth  31  toward the hollow axle  65 , such that the protrusion  32  will cause the projection  51  to push on contact  7 , which will engage contact  9  to establish an electrical connection between the contacts  7  and  9  and thereby generate an electrical signal. 
   If the roller  2  keeps turning, the compressed resilient element  4  will push the slider  3  away from the hollow axle  65  that is led by the roller teeth  21  to mesh again with the slider teeth  31 . Therefore, the contacts  7  and  9  will have no electrical conduction therebetween, causing no electrical signal to be generated, or power to be consumed. 
   Turning to  FIG. 6A , when a user rotates the roller  2  counterclockwise, the slider  3  together with the roller teeth  21  and slider teeth  31  will rotate to a certain angle, and then stop turning due to another outer one of the slider teeth  31  rotating against cylindrical wall  63 . As shown in  FIG. 6B , if the roller  2  keeps turning, the stopped slider  3  will be moved due to the roller teeth  21  gradually pushing the slider teeth  31  toward the hollow axle  65 , such that the protrusion  32  will directly push the projection  52  against contact with contact  8 , and cause contacts  8  and  9  to form an electrical connection therebetween as to generate an electrical signal. 
   If the roller  2  keeps turning, the compressed resilient element  4  will push the slider  3  away from the hollow axle  65  and cause the roller teeth  21  to re-mesh with the slider teeth  31 . Therefore, the contacts  8  and  9  no longer electrically conduct, causing no electrical signal at this moment. 
   However, if the user keep rotating the roller  2  clockwise or counterclockwise, the slider  3  will carry out a reciprocating movement such that a lasting and intermittent electrical signal can be obtained. 
   In additional, referring to  FIG. 5A , the roller teeth  21  slightly contact the cylindrical wall  63  of the roller support  6 . Therefore, depressing the roller  2  will force the roller supporter  6  to deform the flexible structure  61  so as to activate the micro switch  10  to present an extra predetermined function or program. With the structure listed above, the rotating of the roller clockwise or counterclockwise will not only scroll the display on a screen, but also further activate an extra function or program by depressing the micro switch  10 . The present invention can apply to any IA (intelligence appliance) products, any input or output device, such as a trackball, keyboard, game controller, mouse, or even a telephone, or the like. 
   Having thus described a preferred embodiment of the present invention in detail, it will be appreciated that the invention may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would occur to one skilled in the art are intended to be included within the scope of the following claims.