Patent Publication Number: US-6337612-B1

Title: Switch using solenoid

Description:
FIELD OF THE INVENTION 
     The present invention relates to a switch using solenoid utilized in a radio frequency system. More particularly, it relates to a switch using solenoid capable of reducing the number of parts and total size of the switch. 
     DESCRIPTION OF THE PRIOR ART 
     Generally, there are a latching type switch, a fail-safe type switch and the like in switches using solenoid for a radio frequency system. 
     Hereinafter, conventional switches using solenoid will be schematically described, referring to FIGS. 1 and 2. 
     FIG. 1 shows a structure of the latching type switch using solenoid of the prior art. 
     As shown in FIG. 1, the conventional latching type switch has two solenoids  1  and  2  generating a magnetic field when electric current flows thereinto, a permanent magnet  3  located between the two solenoids  1  and  2 , and a rocker  4  disposed under the solenoids  1  and  2 . The rocker  4  is magnetized by the permanent magnet  3  to have N-S-N poles. Therefore, when electric current flows into the solenoid  1  or  2 , the magnetized rocker  4  seesaws with center in the middle portion thereof and performs switching operation. That is, when electric current flows into the right solenoid  2  so that N pole (North Pole) is generated in the lower portion thereof, repulsion occurs between the right solenoid  2  and the right portion of the rocker  4  adjacent to the right solenoid  2 . In this case, the right portion of the rocker  4  is descended and the left portion of the rocker  4  is ascended, so that the left portion of the rocker  4  is contacted to the bottom surface of the left solenoid  1 . 
     On the contrary, when electric current flows into the left solenoid  1 , the left portion of the rocker  4  is descended and the right portion of the rocker  4  is ascended, thereby contacting the right portion to the lower surface of the right solenoid  2 . 
     Further, the conventional latching type switch has a plate spring  5  fixed to the lower portion of the rocker  4 , two push pins  6  and  7  respectively located under both sides of the plate spring  5 , and a plurality of connectors  8   a,    8   b  and  8   c  located under the push pins  6  and  7 . The push pins  6  and  7  have compression coil springs  6   a  and  7   a  respectively surrounding the upper portion thereof, and reeds  6   b  and  7   b  fixed to lower end thereof. 
     The plate spring  5  is moved in upward and downward directions together with the rocker  4 . Therefore, when electric current flows into the right solenoid  2 , the right portion of the plate spring  5  is descended by seesaw of the rocker  4  and presses the push pin  7 . Simultaneously, the reed  7   b  fixed to lower end of the push pin  7  electrically connects the connectors  8   b  and  8   c.  In this state, when electric current flowing into the solenoid  2  is turned off and electric current flows into the left solenoid  1 , the push pin  6  is pressed by seesaw of the rocker  4 . Then, the compression coil spring  7   a  provides a restoring force for the push pin  7 , thereby ascending the moved push pin  7  and separating the reed  7   b  from the connectors  8   b  and  8   c.  Further, the reed  6   b  fixed to the lower end of the push pin  6  electrically connects the connectors  8   a  and  8   b.    
     However, since the conventional latching type switch using solenoid requires two solenoids to move a rocker, the total size of the switch is large and the manufacturing cost is expensive. 
     Meanwhile, FIG. 2 shows a structure of the fail-safe type switch using solenoid of the prior art. 
     As shown in FIG. 2, the conventional fail-safe type switch comprises a solenoid  10  generating a magnetic field while electric current flows thereinto, a pushing rod  20  movably disposed at center portion of the solenoid  10 , a rocker  30  located under the pushing rod  20 , a compression spring  40  disposed on the rocker  30 , and a plurality of connectors  61 ,  62  and  63 . Further, under both sides of the rocker  30 , two push pins  51  and  52  are movably disposed in upward and downward directions. Also, the push pins  51  and  52  have compression coil springs  51   a  and  52   a  respectively surrounding their peripheral surfaces, and reeds  51   b  and  52   b  fixed to their lower ends. 
     In this case, the pushing rod  20  is adjacent to the left portion of the rocker  30  and a lower end of the compression spring  40  is fixed to the right portion of the rocker  30 . 
     In the state, when electric current flows into the solenoid  10  to generate the magnetic field, the pushing rod  20  descends and presses the left portion of the rocker  30 . Then, the rocker  30  seesaws with center in the middle portion thereof, thereby pushing down the left push pin  51  so that the reed  51   b  fixed to the lower end of the push pin  51  electrically connects the connectors  61  and  62  and the compression spring  40  is compressed. The inclined state of the rocker  30  is continuously retained while electric current flows into the solenoid  10 . 
     On the contrary, when electric current flowing into the solenoid  10  is turned off, the right portion of the rocker  30  is descended by restoring force of the compression spring  40  and the left portion of the rocker  30  is ascended. In this case, the right push pin  52  pressed by the right portion of the rocker  30  is descended so that the reed  52   b  electrically connects the connectors  62  and  63 . Simultaneously, the left push pin  51  is ascended by restoring force of the compression coil spring  51   a  surrounding its peripheral portion. 
     However, since the conventional fail-safe type switch, for retaining the state descending the left push pin, must continuously flow electric current into the solenoid, the solenoid radiates high-temperature heat disturbing flow of electric current, thereby weakening the force moving the pushing rod. Therefore, since the size of the solenoid must be large in order to compensate the weakened force, total size of the fail-safe type switch is larger than the conventional latching type switch. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a switch using solenoid capable of reducing the number of parts and a manufacturing cost of the switch, and minimizing total size of the switch. 
     In accordance with an aspect of the present invention, the switch of the present invention comprises a base having a plurality of grooves formed thereon; a plurality of solenoids having an armature respectively, and being respectively disposed above the grooves, wherein the armature is moved in upward and downward directions while an electric current flows into the solenoid; a plurality of connectors respectively disposed in the grooves; and a plurality of contact means for electrically connecting the connectors disposed in each of the grooves, and being movably disposed in the grooves to be pressed by the armature moved in downward direction. 
     Also, in another aspect of the present invention, solenoid used in the switch comprises a bobbin core generating a magnetic field while an electric current flows thereinto, and having a through hole formed vertically therethrough; a conductive coil for guiding the electric current, and being wound round peripheral surface of the bobbin core; an armature being magnetized by the magnetic field generated on the bobbin core, and being movably disposed within the through hole; a plurality of magnetization means generating a definite magnetic field, and being disposed at both ends of the bobbin core; a plurality of first magnetic substances disposed between the bobbin core and each of the magnetization means, and being magnetized by the magnetization means adjacent thereto; and a plurality of second magnetic substances respectively disposed at outer sides of the magnetization means, and being magnetized by the magnetization means adjacent thereto. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects and features of the present invention will become apparent from the following description of the preferred embodiment given in connection with the accompanying drawings, in which: 
     FIG. 1 is a cross-sectional view schematically illustrating a latching type switch using solenoid of a prior art; 
     FIG. 2 is a cross-sectional view schematically showing a fail-safe type switch using solenoid of the other prior art; 
     FIG. 3 is an assembled perspective view schematically illustrating a switch using solenoid according to the present invention; 
     FIG. 4A is a disassembled perspective view showing a solenoid of the FIG. 3; 
     FIG. 4B is a cross-sectional view representing the solenoid of the FIG. 3; 
     FIGS. 5A and 5B are cross-sectional view depicting operation of the solenoid of FIG. 4B, respectively; and 
     FIG. 6 is a cross-sectional view schematically illustrating operation of the switch using solenoid according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, an embodiment of the switch using solenoid according to the present invention will be described in detail, referring to the accompanying drawings. 
     As shown in FIG. 3, the switch using solenoid of the present invention comprises a plurality of solenoids  100  generating magnetic field while electric current flows thereinto. 
     Each of the solenoids  100 , as shown in FIGS. 4A and 4B, has a hollow cylindrical housing  110 , and an I-shaped bobbin core  120  disposed within the housing  110 . The bobbin core  120  has a through hole  122  longitudinally formed in center thereof, and a conductive coil  124  wound round the peripheral surface thereof. Further, each of the solenoid  100  has an I-shaped armature  130  movably disposed within the through hole  122  of the bobbin core  120 . Preferably, the armature  130  is made of magnetic substance. In this case, when electric current flows into the solenoid  100  through the coil  124 , the armature  130  is magnetized and generates predetermined poles. 
     Furthermore, each of the solenoids  100  has a plurality of first ring-shaped magnetic substances  142  and  144  respectively disposed at upper and lower portions between the bobbin core  120  and the armature  130 , a plurality of ring-shaped permanent magnets  150  respectively disposed at outer surface of each of the first magnetic substances  142  and  144 , and a plurality of second ring-shaped magnetic substances  162  and  164  respectively disposed at outer surface of each of the permanent magnets  150 . Each of the first and second magnetic substances  142 ,  144 ,  162 , and  164  is magnetized by one of the permanent magnets  150  adjacent thereto and has a predetermined pole. 
     Further, the switch of the embodiment has a base  200  located under the solenoids  100 . The base  200  has a plurality of grooves  210  formed thereon. In this case, an end of each of the grooves  210  is a common portion to meet at center portion of the base  200  and the upper portions of the grooves  210  are closed. The number of the grooves  210  is equal to the number of the solenoids  100 . 
     Further, the switch using solenoid of the embodiment has a plurality of independent connectors  220  respectively disposed at the other end of each of the grooves  210 , a common connector  230  disposed at the common portion, and a plurality of push pins  240  movably disposed at upper portion of each of the grooves  210 . Each of the push pins  240  has the upper portion protruded from the base  200  and the lower portion located within the groove  210 . In this case, the upper portion of the push pin  240  is surrounded by a compression coil spring  250  and the lower end of the push pin  240  is fixed to a contact reed  260 . When the push pin  240  is pressed by the armature  130 , the contact reed  260  is downwardly moved together with the push pin  240 . Then, the contact reed  260  electrically connects the independent connector  220  to the common connector  230 . The coil spring  250  provides a restoring force that the push pin  240  pressed by the armature  130  returns to its original position. 
     Next, in conjunction to the present invention constructed above, the following describes how the switch using solenoid is operated. 
     In the embodiment, when the magnetic substances  142 ,  144 ,  162 , and  164  are magnetized by the permanent magnets  150 , the first magnetic substances  142  and  144  have S-pole (South pole) and the second magnetic substances  162  and  164  have N-pole (North pole). 
     In this state, as shown in FIGS. 5A and 6, if the forward electric current(designated by a solid line arrow) flows into the solenoid  100  through the coil  124 , the upper portion of the armature  130  has N-pole and the lower portion of the armature  130  has S-pole. 
     In this case, attraction occurs between the upper portion of the armature  130  and the upper first magnetic substance  142  and repulsion occurs between the lower portion of the armature  130  and the lower first magnetic substance  144 . Simultaneously, repulsion occurs between the upper portion of the armature  130  and the upper second magnetic substance  162 , and attraction occurs between the lower portion of the armature  130  and the lower second magnetic substance  164 . Therefore, the armature  130  is descended and contacted to the upper first magnetic substance  142  and the lower second magnetic substance  164 . In this case, the descended armature  130  presses the push pin  240  so that the contact reed  260  fixed to the push pin  240  is downwardly moved and electrically connects the independent connector  220  to the common connector  230 . 
     Then, even if electric current flowing into the armature  130  is turned off, the armature  130  can continuously retain the state contacted to the magnetic substances  142  and  164  by the magnetic force of the permanent magnet  150 . 
     On the contrary, as shown in FIG. 5B, if the reverse electric current(designated by a dotted line arrow) flows into solenoid  100  through the coil  124 , the upper portion of the armature  130  has S-pole and the lower portion of the armature  130  has N-pole. 
     In this case, repulsion occurs between the upper portion of the armature  130  and the upper first magnetic substance  142 , and attraction occurs between the lower portion of the armature  130  and the lower first magnetic substance  144 . Simultaneously, attraction occurs between the upper portion of the armature  130  and the upper second magnetic substance  162 , and repulsion occurs between the lower portion of the armature  130  and the lower second magnetic substance  164 . Therefore, the armature  130  is ascended, thereby being contacted to the upper second magnetic substance  162  and the lower first magnetic substance  144 . In this case, the push pin  240  pressed by the armature  130  and the contact reed  260  fixed to the push pin  240  are upwardly moved by elastic force of the coil spring  250  surrounding peripheral surface thereof. Even if the reverse electric current flowing into the armature  130  is turned off, the armature  130  can continuously retain the state contacted to the magnetic substances  144  and  162  by the magnetic force of the permanent magnet  150 . 
     At the both case, a movement of the armature  130  is completed within about 0.01 second(i.e., 10 milliseconds) and a flow time of electric current required for moving the armature  130  is about 0.03 seconds(i.e., 30 milliseconds). Therefore, the solenoid  100  does not radiate high-temperature heat disturbing flow of electric current. 
     Since the switch according to the present invention constructed and operated as above-mentioned does not require a rocker used in the prior art, it is possible to reduce the number of parts. Therefore, the manufacturing cost and total size of the switch can be minimized. 
     Further, since it is unnecessary to flow electric current into the solenoid continuously, the electric power consumption can be decreased. 
     While the present invention has been described with respect to certain preferred embodiments only, other modifications and variation may be made without departing from the spirit and scope of the present invention as set forth in the following claims.