Patent Publication Number: US-6985115-B2

Title: Automatic antenna for portable electronic device

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to automatic antennas, and particularly to an automatic antenna for a handheld radiotelephone. 
   2. Prior Art 
   In recent times, communication terminals have been in great demand because of the widespread use of devices such as cellular phones and pagers for mobile communication. In wireless communication systems, wireless communication terminals transmit signals to base stations. The base stations relay the signals to intended recipient communication terminals all the time, regardless of whether the intended recipient communication terminals are in communication-waiting mode. Portable electronic devices such as mobile phones and cordless telephones generally transmit and receive signals by antenna, and antennas that are used in these devices are in great demand. 
   Automatic antennas for portable electronic devices can be divided into two categories: built-in antennas and built-out antennas. Built-out antennas are generally exposed outside of the portable electronic device. Built-in antennas are retained in a housing of the portable electronic device, and generally are not exposed out of the portable electronic device. With a built-in antenna, the overall length of the portable electronic device is reduced, and the radiation of magnetic fields is greatly decreased. However, the built-in antenna is subject to shielding phenomena, which can greatly interfere with the transmission and reception of signals. In particular, when the housing of the portable electronic device is made of an alloy such as aluminum combined with magnesium, the shielding phenomena are serious and problematic. Built-out antennas provide better transmission and reception of signals than built-in antennas. However, in most present-day portable electronic devices, the built-out antenna is located adjacent the earphone. There is some scientific research suggesting that frequent use of this kind of portable electronic device exposes the user&#39;s brain to much electromagnetic radiation which may be harmful. 
   A typical built-out antenna can be adjusted between an extended position and a retracted position. The built-out antenna is generally operated by hand. P.R. China Patent Application No. 99110465.X describes a built-out antenna for a mobile phone including a protrusion disposed on one end of the antenna. The protrusion extends out of a housing of the mobile phone. When needed, the antenna can be drawn out of the housing or pressed into the housing by operating the protrusion. However, both of these operations require the user to use both his/her hands together. If the user has only one hand free, he/she cannot operate the antenna. In addition, the protrusion may be unduly thick, which may detract from the aesthetic appearance of the mobile phone. 
   To solve the above-mentioned problem, some manufacturers utilize electric power to drive the antenna. A mobile phone with this kind of antenna is disclosed in P.R. China Patent Application No. 99802898.3. The antenna has a driving mechanism connected with the electric power source of the mobile phone. The antenna is extended out of the housing by the driving mechanism, and retracted back into the housing by the driving mechanism. However, it is generally necessary for the mobile phone to have an enhanced electric power source. In addition, the driving mechanism is complicated and bulky, and adds to an overall size of the mobile phone. Furthermore, the power consumption of the mobile phone is increased, which adds to the cost of owning the mobile phone. 
   Therefore, a new antenna device is desired in order to overcome the above-described problems. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the present invention is to provide an automatic antenna for a portable electronic device which has a relatively simple configuration and convenient operation. 
   Another object of the present invention is to provide an automatic antenna for a portable electronic device which occupies a relatively small space of the portable electronic device. 
   To achieve the above-mentioned objects, an automatic antenna for a portable electronic device of the present invention is adapted to be used with a main body of the portable electronic device. The main body comprises an antenna holder and an antenna groove. The automatic antenna comprises a shaft having an end key, a securing element defining a hole, a hollow sliding element having a plurality of sliding arms symmetrically disposed on an outer wall thereof, a hollow rotating element, a housing, and a spring disposed between the rotating element and the housing. The securing element has a plurality of blocks symmetrically disposed on an inner wall thereof. The blocks define a plurality slots therebetween. Each block defines a recess. The sliding element defines an end surface having peaks. The rotating element includes a peripheral cam portion. The cam portion has a cam surface movably engaging with the peaks of the sliding element, and a plurality of projections protruding from a periphery of the cam portion. The shaft extends through the securing element, the sliding element, the rotating element, the spring and the housing in that order. The sliding arms can slide within the slots and recesses, and the projections can slide in the slots. When the antenna is in a retracted position, the projections are our of the slots, the spring biases the cam surface against the peaks of the sliding element so that the rotating element has a tendency to rotate, and the projections are blocked from rotating by the blocks. 
   In use of the antenna, the shaft is pressed down and drives the sliding element. The sliding element pushes the rotating element, with the peaks of the sliding element pushing the cam surface of the rotating element. The sliding arms slide within the slots and the recesses, and corresponding sliding arms push the projections of the rotating element out of the slots. Then the rotating element immediately rotates, with the spring driving the cam surface to ride along the peaks of the sliding element. At this time, the shaft is released. The spring drives the rotating element to continue rotating, with the cam surface riding onto and along ends of the blocks. The projections reach corresponding slots, and the spring drives the rotating element so that the projections slide into the slots. The rotating element pushes the sliding element, and the sliding element pushes the key of the shaft to be exposed out of the securing element. In this position, the projections are latched in the slots. The user can then grasp the key and pull the shaft up and out from the securing element a desired distance. 
   Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded, isometric view of an automatic antenna in accordance with a preferred embodiment of the present invention, and part of a body of an associated portable electronic device; 
       FIG. 2  is similar to  FIG. 1 , but viewed from another aspect; 
       FIG. 3  is an enlarged, assembled view of a sliding element and a rotating element of the automatic antenna of  FIG. 1 ; 
       FIG. 4  is an enlarged, cut-away view of a securing element of the automatic antenna shown in  FIG. 2 ; 
       FIG. 5  is an assembled view of  FIG. 1 ; and 
       FIG. 6  is a cross-sectional view taken along line VI–VI of  FIG. 5 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings in detail,  FIGS. 1 and 2  show a mechanism of an automatic antenna  100  for a portable electronic device (not shown). The antenna  100  comprises a shaft  20  as an antenna body, a securing element  30 , two springs  40 ,  70 , a sliding element  50 , a rotating element  60 , a housing  80 , a sleeve  90 , a pin  10 , and a screw  11 . 
   A body  21  (only partly shown) of a mobile phone using the antenna  100  has an antenna holder  212  at a top end thereof, and an antenna groove  214  along one side thereof to provide a receiving space for the antenna  100 . The antenna holder  212  extends from the top end of the body  21 . The antenna holder  212  defines a generally rectangular chamber  218  therein, and a restricting hole  216  in a bottom end thereof. The antenna groove  214  is adjacent to one sidewall of the body  21 , and extends from the bottom end of the antenna holder  212  to a bottom end of the body  21 . 
   The shaft  20  is long and cylindrical, and has a key  22  at a top end thereof. The key  22  comprises a cylindrical resisting portion  22   b , and a discoid operating portion  22   a  at a top end of the resisting portion  22   b.    
   Referring also to  FIG. 4 , the securing element  30  is substantially a hollow cylinder. A configuration of a main body of the securing element  30  matches that of the antenna holder  212 . The securing element  30  defines a hole (not labeled) therethrough. A partition  300  extends from an inner peripheral wall of the securing element  30  at the hole, thereby dividing the hole into: (i) a keyhole  32  for receiving the operating portion  22   a  of the shaft  20 ; and (ii) a receiving hole  34  for receiving the spring  40  and the sliding element  50 . The securing element  30  further defines an enlarged, shallow outer opening  36  at the receiving hole  34 . The keyhole  32 , the receiving hole  34  and the outer opening  36  are in communication with each other, in that order from top to bottom. Three blocks  320  as lock means are provided on an inner peripheral wall of the securing element  30  in the receiving hole  34 . The blocks  320  are evenly spaced apart from each other, and cooperatively define three slots  3200  therebetween. Each block  320  includes a first protrusion  322  and a second protrusion  324 . The second protrusion  324  defines a recess  3240  adjacent the first protrusion  322 . The first protrusion  322  is longer than the second protrusion  324 , and the first protrusion  322  is thicker than the second protrusion  324 . A bottom end of the first protrusion  322  has a first incline  3222 , and a bottom end of the second protrusion  324  has a second incline  3242 . The first incline  3222  slants radially outwardly and toward the bottom of the securing element  30 . The second incline  3242  slants radially outwardly and toward the top of the securing element  30 . 
   Referring also to  FIGS. 1–3 , the sliding element  50  is substantially a hollow cylinder. The sliding element  50  comprises a hole  51  in a top end thereof, a cavity  52  in a bottom end thereof, six sliding arms  54  evenly spaced apart on a circumferential wall thereof, and an end surface  56 . The sliding element  50  is received in the securing element  30 , with the sliding arms  54  sliding into the slots  3200  and the recesses  3240 . The end surface  56  comprises six valleys  562  and six peaks  564 , the peaks  564  adjoining the sliding arms  54  respectively. 
   The rotating element  60  is substantially a hollow cylinder, and comprises a bottom portion  64 , an enlarged, intermediate cam portion  61 , and a reduced top portion  62 . The cam portion  61  includes an undulating cam surface  602  at a front end thereof, corresponding to the end surface  56  of the sliding element  50 . Three evenly spaced projections  604  are provided on a circumferential wall of the cam portion  61 . The cam surface  602  engages with the end surface  56  of the sliding element  50 , and the projections  604  can slide within the slots  3200  of the securing element  30 . The top portion  62  defines a top hole  620 , and the bottom portion  64  defines a bottom hole  640 . A diameter of the top hole  620  is less than that of the bottom hole  640 , thereby defining an annular inner step (not labeled) between the top hole  620  and the bottom hole  640 . The top portion  62  is received in the cavity  52  of the sliding element  50 . 
   Referring also to  FIG. 6 , the housing  80  is substantially a step-like, hollow flattened cylinder. The housing  80  includes an enlarged, flat positioning head  81 , which is locked in the outer opening  36  of the securing element  30 . The housing  80  defines a top circular hole  800  for receiving the bottom portion  64  of the rotating element  60 , an intermediate inner hole  82 , and a bottom latch hole  84 . The top hole  800 , the inner hole  82  and the latch hole  84  are all coaxial with one another. A diameter of the top hole  800  is larger than that of the latch hole  84 . The diameter of the latch hole  84  is larger than that of the inner hole  82 , thereby defining an inner step where the inner hole  82  adjoins the latch hole  84 . The diameter of the top hole  800  is larger than that of the inner hole  82 , thereby defining an inner step where the inner hole  82  adjoins the top hole  800 . The housing  80  also defines a positioning hole  86  in an outer wall thereof, perpendicular to the axis of the housing  80 . 
   The sleeve  90  is a long, hollow cylinder received in the antenna groove  214  of the body  21 . 
   The pin  10  is a hollow cylinder, and defines a top inserting hole  10   a . The pin  10  has a plurality of elastic arms  10   b  at a bottom end thereof, and an exterior annular bead  10   c  formed adjacent the elastic arms  10   b . The elastic arms  10   b  are furcated and slant slightly outwardly. The inserting hole  10   a  interferingly receives a bottom end of the shaft  20  therein, and the elastic arms  10   b  provide friction for the shaft  20  to be held in a desired position inside the sleeve  90 . 
   The springs  40 ,  70  are metallic and helical. The spring  40  is received in the receiving hole  34  of the securing element  30  and located around the resisting portion  22   b  of the shaft  20 . A top end of the spring  40  resists the partition  300  of the securing element  30 . A bottom end of the spring  40  resists a top end of the sliding element  50 , such that the end surface  56  of the sliding element  50  tightly engages with the cam surface  602  of the rotating element  60 . The spring  70  is placed around the shaft  20 , and a top portion of the spring  70  is received in the bottom hole  640  of the rotating element  60 . One end of the spring  70  resists the inner step of the rotating element  60  where the top hole  620  adjoins the bottom hole  640 . The other end of the spring  70  is received in the circular hole  800  of the housing  80 , and resists the inner step of the housing  80  where the inner hole  82  adjoins the top hole  800 . 
   In assembly, firstly, the spring  40 , the sliding element  50  and the rotating element  60  are received in the securing element  30  in that order. The spring  40  and the sliding element  50  are received in the receiving hole  34 , with the sliding arms  54  of the sliding element  50  being received in the slots  3200  and the recesses  3240 . The spring  40  is thus engaged between the partition  300  and the sliding element  50 . The top portion  62  of the rotating element  60  is inserted into the cavity  52  of the sliding element  50 . The cam surface  602  of the rotating element  60  contacts the peaks  564  of the end surface  56  of the sliding element  50 . The projections  604  abut against portions of the second inclines  3242  adjacent the recesses  3240  and contact the end surface  56  of the sliding element  50 . Simultaneously, the projections  604  are stopped by the first protrusions  322  such that the rotating element  60  cannot rotate counterclockwise (as viewed from a bottom thereof). However, the rotating element  60  has a tendency to rotate counterclockwise (see below). The spring  70  is inserted into the bottom hole  640  of the rotating element  60  and abuts the inner step of the rotating element  60 . 
   The housing  80  is inserted in the chamber  218  of the antenna holder  212 . The screw  11  is inserted through the positioning hole  86  of the housing  80  and engaged in the restricting hole  216  of the antenna holder  212 , so that the housing  80  is tightly secured in the antenna holder  212 . The positioning head  81  abuts a top end of the antenna holder  212 . The bottom portion  64  of the rotating element  60  is inserted in the hole  800  of the housing  80 , such that the positioning head  81  of the housing  80  is received in the outer opening  36  of the securing element  30 , and the securing element  30  abuts the top end of the antenna holder  212 . The securing element  30  is then fixed on the antenna holder  212  by melting, ultrasonic welding or gluing. The sleeve  90  is received in the antenna groove  214  of the body  21 . The shaft  20  is extended through the securing element  30 , the spring  40 , the sliding element  50 , the rotating element  60 , the spring  70 , the housing  80  and the sleeve  90  in that order, with the resisting portion  22   b  of the key  22  of the shaft  20  abutting against the sliding element  30 . The bottom end of the shaft  20  is inserted in the inserting hole  10   a  of the pin  10  such that the pin  10  is secured on the bottom end of the shaft  20 . The shaft  20 , the pin  10  and the sleeve  90  are electrically connected with a printed circuit board (not shown) of the mobile phone. 
   Referring also to  FIG. 3  and  FIG. 6 , when the antenna  100  is in a retracted position, the key  22  is located in the keyhole  32  and the receiving hole  34  of the securing element  30 , with the operating portion  22   a  located in a top of the keyhole  32 . The peaks  564  of the end surface  56  of the sliding element  50  contact the cam surface  602  of the rotating element  60  under the cooperative forces of the springs  40 ,  70 . Three peaks (not labeled) of the cam surface  602  that adjoin the projections  604  resist the end surface  56 . The interference between the cam surface  602  and the end surface  56  is such that the rotating element  60  has a tendency to rotate counterclockwise (as viewed from the bottom thereof). Nevertheless, the rotating element  60  cannot rotate because the projections  604  are stopped by the first protrusions  322 . 
   In use of the antenna  100 , the operating portion  22   a  of the key  22  is pressed down, and the resisting portion  22   b  drives the sliding element  50  in the Y direction. The sliding element  50  drives the rotating element  60  in the Y direction, with the peaks  564  of the sliding element  50  pushing the cam surface  602  of the rotating element  60 . The sliding arms  54  slide within the slots  3200  and the recesses  3240 , and three of the sliding arms  54  push the projections  604  away from the second inclines  3242  until the projections  604  reach positions below the first inclines  3222 . Then the rotating element  60  immediately rotates counterclockwise, with the spring  70  driving the cam surface  602  to ride along the peaks  564  of the sliding element  50 . The cam surface  602  rides from the peaks  564  to the first inclines  3222 . At this time, the operating portion  22   a  is released. The interference between the cam surface  602  and the first inclines  3222  is such that the rotating element  60  has a tendency to rotate counterclockwise (as viewed from the bottom thereof). Thus the spring  70  drives the rotating element  60  to continue rotating counterclockwise, with the projections  604  of the rotating element  60  moving along the first inclines  3222  until the projections  604  reach the slots  3200 . Then the spring  70  drives the rotating element  60  in the X direction, with the projections  604  sliding in the slots  3200 . The rotating element  60  pushes the sliding element  50  in the X direction, and the sliding element  50  pushes the resisting portion  22   b  in the X direction. Thus the operating portion  22   a  is pushed out of the keyhole  32 . In this position, the projections  604  of the rotating element  60  are latched in the slots  3200 . 
   Then the user can grasp the operating portion  22   a  and pull the shaft  20  up and out from the securing element  30  a desired distance. The friction force of the elastic arms  10   b  in the sleeve  90  enable the pin  10  to be stably located in any position inside the sleeve  90 . Thus the shaft  20  can be stably located in any desired position. When the shaft  20  is drawn out to a fully extended position, the pin  10  moves into the housing  80  and the bead  10   c  is stopped by the inner step of the housing  80  where the inner hole  82  adjoins the latch hole  84 . Thus the shaft  20  cannot be withdrawn beyond the fully extended position, and cannot fall out of the securing element  30 . 
   When the antenna  100  is no longer needed, the operating portion  22   a  is pushed down toward the securing element  30 . When the operating portion  22   a  nears the keyhole  32 , the resisting portion  22   b  contacts the sliding element  50  and drives the sliding element  50  in the Y direction. The sliding element  50  drives the rotating element  60  in the Y direction, with the peaks  564  of the sliding element  50  pushing the cam surface  602  of the rotating element  60 . The sliding arms  54  slide within the slots  3200  and the recesses  3240 , and three of the sliding arms  54  push the projections  604  out of the slots  3200 . Then the rotating element  60  immediately rotates counterclockwise, with the spring  70  driving the cam surface  602  to ride along the peaks  564  of the sliding element  50 . The cam surface  602  rides from the peaks  564  to the second inclines  3242 . At this time, the operating portion  22   a  is located well within the top of the keyhole  32 , and is released. The interference between the cam surface  602  and the second inclines  3242  is such that the rotating element  60  has a tendency to rotate counterclockwise (as viewed from the bottom thereof). Thus the spring  70  drives the rotating element  60  to continue rotating counterclockwise, with the projections  604  of the rotating element  60  moving along the second inclines  3242  until the projections  604  are stopped by the first projections  322 . At this time, the operating portion  22   a  is still located within the top of the keyhole  32 , the sliding element  50  and the rotating element  60  are located in their original positions along the X-Y axis, and the antenna  100  is once again in the retracted position. 
   From the above description, it will be apparent that the antenna  100  of the present invention has a relatively simple configuration which provides highly convenient operation of the operating portion  22   a  of the key  22 . 
   It is believed that the present invention and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the example hereinbefore described merely being a preferred or exemplary embodiment of the invention.