Patent Publication Number: US-6670871-B1

Title: Polar relay

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a 371 of PCT/JP00/08179. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a polar (or polarized) relay, and more particularly to a polar relay of a balanced-armature type. Also, the present invention relates to an information processing apparatus provided with a balanced-armature type polar (or polarized) relay. The present invention further relates to a method of manufacturing a balanced-armature type polar relay. 
     BACKGROUND ART 
     A polar relay that is comprised of a base, an electromagnet incorporated into the base, a permanent magnet provided in conjunction with the electromagnet, an armature supported pivotably on the base, the armature having a pair of abutting surfaces in opposite end regions at a distance from the pivoting center of the armature, which are opposed to and capable of abutting on a pair of core polar surfaces of the electromagnet, at least one electrically conductive plate spring pivotable on the base along with the armature, movable contacts provided on the opposite ends of each of at least one conductive plate spring, and a plurality of fixed contacts disposed securely on the base so as to be respectively opposed to and capable of coming into contact with the corresponding movable contacts, is known as a balanced-armature type polar relay. Generally, this type of polar relay has advantages of higher sensitivity, shorter operating time, etc., in comparison with a non-polarized relay, as well as being easy to reduce in size and power consumption, so that, in recent years, they have been increasingly utilized in various information processing apparatuses, such as modems and facsimiles in offices and homes, which are adapted to be connected to telecommunications channels or electric communication lines. 
     When telecommunications-channel connectable equipment are to be connected to a telecommunications channel (e.g., a telephone circuit), it is required that circuits (a power circuit, a signal circuit) of the connectable equipment are isolated from the telecommunications channel with sufficient dimensions for insulation (i.e., sufficient insulation distances), as prescribed, for respective utilized voltages, in the international standard IEC60950. Conventionally, in order to assure such insulation distances as prescribed, certain measures have been taken, wherein a non-polarized relay having a relatively large open- or break-contact distance (that is, a maximum distance between contacts during the travel of an armature) is adopted as a relay to be mounted in the telecommunications-channel connectable equipment, or wherein a transformer is interposed between the circuit of the connectable equipment and the telecommunications channel. 
     The above described conventional measures for insulation meeting the requirements of IEC60950 have some problems to be solved, from the viewpoint of reduction in size and in power consumption. First, in the case of mounting a non-polarized relay in the connectable equipment, the non-polarized relay has a long armature travel and thus the finished product has relatively large external dimensions, which may become factors inhibiting the reduction in size and power consumption of the connectable equipment. On the other hand, when a low power-consumption polar relay, as described above, is mounted in the telecommunications-channel connectable equipment, the polar relay has, in general, a relatively small open- or break-contact distance, which would require the provision of a transformer, mounted in the connectable equipment, to be interposed between a circuit of the connectable equipment and the telecommunications channel, so as to meet the requirements of IEC60950. Thus, in this case, even when a sufficiently small polar relay is used, the existence of the transformer may resultingly hamper the size reduction of the telecommunications-channel connectable equipment. 
     Further, in order to meet the requirements of IEC60950, it is desired for a relay to be mounted in telecommunications-channel connectable equipment such that sufficient insulation distances are assured not only between contacts in an opened state but also between, for example, a contact and a coil of an electromagnet, or between contacts arranged side-by-side in the case of a double-circuit type relay. Especially, in a miniature polar relay, it has been a problem to assure the insulation distances between various above-described components. 
     DISCLOSURE OF THE INVENTION 
     It is an object of the present invention to provide a polar relay, of a balanced-armature type, that is capable of assuring, by its own structure, sufficient insulation distances, meeting the requirements of IEC60950, when it is mounted in telecommunications-channel connectable equipment. 
     It is another object of the present invention to provide a polar relay, of a balanced-armature type, that is capable of increasing insulation distances required between contacts in an opened state, while the external dimensions of the finished product are prevented from increasing as effectively as possible. 
     It is still another object of the present invention to provide a polar relay, of a balanced-armature type, that is capable of assuring sufficient insulation distances required between a contact and a coil, while the external dimensions of the finished product are prevented from increasing as effectively as possible. 
     It is still another object of the present invention to provide a polar relay, of a balanced-armature type, that is capable of assuring sufficient insulation distances required between contacts arranged side-byside, while the external dimensions of the finished product are prevented from increasing as effectively as possible. 
     It is still another object of the present invention to provide a miniature information processing apparatus, of a low power-consumption type, that is capable of assuring sufficient insulation distances meeting the requirements of IEC60950, when it is connected to a telecommunications channel. 
     It is still another object of the present invention to provide a method for manufacturing a polar relay that  15  is capable of assuring, by its own structure, sufficient insulation distances, meeting the requirements of IEC60950, when it is mounted in telecommunications-channel connectable equipment. 
     In order to accomplish the above objects, the present invention provides a polar relay comprising a base; an electromagnet incorporated into the base; a permanent magnet provided in conjunction with the electromagnet; an armature pivotably supported on the base and having a pair of abutting surfaces disposed in opposite end regions at a distance from a pivoting center, which are respectively opposed to and capable of abutting on a pair of core polar surfaces of the electromagnet; at least one electrical conductive plate spring pivotable on the base along with the armature; a plurality of movable contacts provided on opposite ends of each of the at least one electrical conductive plate spring; and a plurality of fixed contacts arranged securely on the base, the fixed contacts being respectively opposed to and capable of coming into contact with the movable contacts; wherein the maximum distance between one of the movable contacts and one of the fixed contacts, capable of coming into contact with each other during the travel of the armature, is set to 1 mm or more. 
     In the preferred aspect, the polar relay is constituted such that at least one of each of the pair of abutting surfaces of the armature and each of the pair of core polar surfaces of the electromagnet, opposed to the abutting surface, is formed as an inclined surface for reducing an angle between opposed surfaces, during a mutual abutment, as much as possible, and that the armature passes, during the travel thereof, a position where each of the pair of abutting surfaces oppositely faces a corresponding one of the pair of core polar surfaces in parallel with each other. 
     In this arrangement, the thickness of the opposite end regions in a pivoting direction of the armature may gradually decrease toward opposite ends of the armature, the pair of abutting surfaces being thereby formed as the inclined surfaces. 
     In this case, it is advantageous that a non-magnetic layer is formed on one of the abutting surfaces of the armature which is arranged on a make side. 
     It is also preferred that the thickness of the non-magnetic layer is uniform. 
     The permanent magnet may be fixedly connected to the armature in a position deviated toward a break side. 
     In another preferred aspect, comprising at least two electrically conductive plate springs, the polar relay further comprises an insulating member integrally connecting the armature with the at least two electrically conductive plate springs so as to be spaced in a lateral direction perpendicular to a pivoting direction of the armature and arranged side-by-side while at least the abutting surfaces and the movable contacts are exposed, wherein the insulating member covers most of an intermediate portion of the armature located between the opposite end regions, and wherein the at least two electrically conductive plate springs are disposed so as to define, at proximal end portions thereof projecting from the insulating member, a lateral distance from the insulating member, smaller than a lateral distance between the movable contacts and the abutting surfaces. 
     In this arrangement, the polar relay may be provided, wherein the thickness of the opposite end regions in the pivoting direction of the armature gradually decreases toward opposite ends of the armature, and wherein a dimension of the opposite end regions in a lateral direction of the armature, perpendicular to the pivoting direction, is larger than a dimension of the intermediate region in the lateral direction. 
     In a further preferred aspect, the polar relay is provided wherein the electromagnet includes a core, an insulating bobbin attached to the core with the pair of core polar surfaces exposed, and a coil wound on the insulating bobbin, wherein the base includes an insulating upper plate interposed between the armature and the coil and cooperating with the insulating bobbin to increase dimensions for insulation, required between the pair of core polar surfaces and the coil, and wherein the insulating bobbin and the insulating upper plate are provided with combined portions to be complementarily combined with each other at a location between the pair of core polar surfaces and the coil. 
     In this arrangement, it is advantageous that the core includes, near the pair of core polar surfaces, overhang portions projecting from a surface of the insulating bobbin, and that the insulating bobbin covers the core except for the pair of core polar surfaces as well as regions including the overhang portions and surrounding the core polar surfaces. 
     Also, the base may include an insulating bottom plate cooperating with the insulating upper plate to increase dimensions for insulation, required between a plurality of terminals respectively having the fixed contacts thereon and the coil, and the insulating upper plate and the insulating bottom plate may be complementarily combined with each other at a location between the terminals and the coil. 
     In this case, it is preferred that a sealant is applied to the complementarily combined portions of the insulating upper plate and the insulating bottom plate for sealing any gap between the combined portions. 
     In a further preferred aspect, the polar relay includes an insulating surface zone provided between the pair of core polar surfaces of the electromagnet and the plurality of fixed contacts so as not to expose the surfaces to each of the fixed contacts. 
     The polar relay according to the present invention is effectively usable, especially, for assuring dimensions for insulation, required between circuits as prescribed in IEC60950 regarding an information processing apparatus connectable to a telecommunications channel. 
     The present invention further provides an information processing apparatus connectable to a telecommunications channel, wherein a polar relay, as described above, is arranged between an inner circuit of the information processing apparatus and a telecommunications channel to assure dimensions for insulation, required between circuits. 
     The present invention further provides a method for manufacturing a polar relay, as described above, comprising providing a magnetic plate including a flat first surface, and a second surface having a major flat-face portion parallel to the first surface and an inclined-face portion crossing at an obtuse angle with the major flat-face portion and extending in a direction approaching the first surface; forming a non-magnetic layer having a uniform thickness on the first surface of the magnetic plate in a region located opposite to the inclined-face portion; opposing the second surface of the magnetic plate to a flat supporting plane, and securely placing the magnetic plate on the supporting plane; pressing a region of the first surface including the non-magnetic layer, to deform the magnetic plate while maintaining the uniform thickness of the non-magnetic layer until a surface of the non-magnetic layer exhibits a mirror image shape of the inclined-face portion provided in the second surface and the inclined-face portion shifts to a plane common to the major flat-face portion; and forming, from the magnetic plate, the armature including a region of the non-magnetic layer arranged on either one of the pair of abutting surfaces. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will become more apparent from the following description of preferred embodiments in connection with the accompanying drawings, in which: 
     FIG. 1 is an exploded perspective view showing a polar relay according to an embodiment of the present invention; 
     FIG. 2 is an enlarged perspective view showing an upper plate member of a base in the polar relay of FIG. 1; 
     FIG. 3 is an enlarged perspective view showing an electromagnet in the polar relay of FIG. 1; 
     FIG. 4 is a vertical sectional view showing the electromagnet of FIG. 3; 
     FIG. 5 is a plan view showing the electromagnet of FIG. 3; 
     FIG. 6 is an enlarged perspective view showing an assembly of an armature and an electrically conductive plate spring in the polar relay of FIG. 1; 
     FIG. 7 is a plan view showing the assembly of FIG. 6; 
     FIG. 8A is a schematic front view showing the position of an armature when contacts are opened, in a conventional polar relay; 
     FIG. 8B is a schematic front view showing the position of an armature when contacts are opened, in the polar relay of FIG. 1; 
     FIG. 8C is a schematic front view showing the position of an armature when contacts are closed, in the polar relay of FIG. 1; 
     FIG. 9A is an enlarged view showing a configuration of a mutual abutment between the armature shown in FIG. 8C and a core; 
     FIG. 9B is an enlarged view showing an undesirable configuration of a mutual abutment between an armature and a core; 
     FIG. 10 is an enlarged view showing the end region of the armature of FIG. 6; 
     FIG. 11A is a schematic front view illustrating a stage before pressing, in a process for manufacturing the armature of FIG.  9 A. 
     FIG. 11B is a schematic front view illustrating a stage after pressing, in the process for manufacturing the armature of FIG.  9 A. 
     FIG. 12 is a sectional view showing the overall construction of the polar relay of FIG. 1; 
     FIG. 13 is a schematic view showing a modification of a magnetic circuit in the polar relay of FIG. 1; 
     FIG. 14 is a sectional view, taken along a line XIV—XIV in FIG. 15, showing an assembly of the base and the electromagnet in the polar relay of FIG. 1; 
     FIG. 15 is a sectional view showing the assembly of FIG. 14, taken along a line XV—XV therein; 
     FIG. 16 is an enlarged perspective view showing a bottom plate member of the base in the polar relay of FIG. 1; 
     FIG. 17 is a sectional view showing the assembly of FIG. 14, taken along a line XVII—XVII therein; 
     FIG. 18 is a bottom plan view showing the assembly of FIG. 14; 
     FIG. 19A is a schematic view showing an indirect insulating-wall structure between the contact and the coil in the polar relay of FIG. 1; 
     FIG. 19B is a schematic view showing an indirect insulating-groove structure between the contact and the coil in the polar relay of FIG. 1; 
     FIG. 20 is a schematic circuit diagram showing the construction of an information processing apparatus according to an embodiment of the present invention; and 
     FIG. 21 is a schematic circuit diagram showing the construction of an information processing apparatus according to another embodiment of the present invention. 
    
    
     BEST MODES FOR CARRYING OUT THE INVENTION 
     The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Throughout the drawings, the same or similar components are denoted by common reference numerals. 
     Referring to the drawings, FIG. 1 shows a polar relay  10  according to an embodiment of the present invention. The polar relay  10  according to the illustrated embodiment has a balanced-armature construction of a small-size, low-power-consumption type, which can be used in an information processing apparatus, such as a modem or a facsimile, adapted to be connected to a telecommunications channel. 
     As shown in FIG. 1, the polar relay  10  includes a base  12 , an electromagnet  14  incorporated into the base  12 , a permanent magnet  16  provided in conjunction with the electromagnet  14 , an armature  22  pivotably supported like a seesaw on the base  12 , the armature having a pair of abutting surfaces  20  disposed in opposite end regions at a distance from the pivoting center of the armature, which are respectively opposed to and capable of abutting on a pair of core polar surfaces  18  of the electromagnet  14 , two electrically conductive plate springs  24  pivotable on the base  12  along with the armature  22 , movable contacts  26  provided on opposite ends of each of the conductive plate springs  24 , and a plurality of fixed contacts  28  arranged securely on the base  12 , the fixed contacts being respectively opposed to, and capable of coming into contact, with the movable contacts  26 . 
     The base  12  includes an upper plate member  30  and a bottom plate member  32 , each of which is an electrically insulating resinous mold, and which are combined with each other. The electromagnet  14  is securely contained in the internal space defined by the upper plate member  30  and the bottom plate member  32 . The upper plate member  30  of the base  12  is a generally rectangular parallelepiped partial case for covering mainly the upper portion of the electromagnet  14 . The upper plate member is provided in the longitudinal opposite end regions in the upper side thereof with a pair of openings  34  penetrating therethrough for receiving and exposing a pair of core polar surfaces  18  of the electromagnet  14 , and in the center region of the upper side thereof with two supports  36  integrally protruding therefrom so as to provide a pivoting fulcrum for the armature  22 . The bottom plate member  32  of the base  12  is a generally rectangular parallelepiped partial case for covering mainly the lower portion of the electromagnet  14 . 
     Further, on the upper side of the upper plate member  30 , a pair of fixed contacts  28  positioned at longitudinal opposite ends and one common contact  38  positioned generally at a midpoint between the fixed contacts  28 , are provided to be aligned along each of the lateral edges extending in the longitudinal direction and are insulated from each other. As is clearly shown in FIG. 2, the fixed contacts  28  and the common contacts  38  are arranged symmetrically with respect to an upper-side center line  30   a  linking the openings  34  with each other, and thus constitute a make contact  28   a , a break contact  28   b  and a common contact  38  on each side of the center line  30   a . Therefore, the polar relay  10  has the structure of a dual-circuit relay. 
     Each fixed contact  28  and each common contact  38  are carried respectively on one end of a fixed terminal  40  and of a common terminal  42 , the terminals being independent of each other. The fixed terminals  40  and the common terminals  42  are integrally and fixedly built in the upper plate member  30  by, e.g., being placed as inserts in a mold (not shown) during the molding of the upper plate member  30 . Each fixed terminal  40  and each common terminal  42  are provided with legs  40   a ,  42   a  extending downward from each lateral side of the upper plate member  30 . Further, a pair of coil terminals  44  connected with the coil of the electromagnet  14 , as described later, is integrally and fixedly built in the upper plate member  30  by, e.g., an insert molding process. Each coil terminal  44  is provided with a leg  44   a  extending downward from the upper plate member  30 . The legs  40   a ,  42   a  and  44   a  of the fixed terminal  40 , common terminal  42  and coil terminal  44  are arranged substantially in parallel with each other. 
     The electromagnet  14  includes an iron core  46 , a bobbin  48  attached to the core  46  so as to expose a pair of core polar surfaces  18 , and a coil  50  wound on the bobbin  48 . As shown in FIGS. 3 to  5 , the core  46  includes a base portion  46   a  having a generally rectangular plate shape and a pair of arm portions  46   b  extending integrally from the longitudinal opposite ends of the base portion  46   a  in a direction generally perpendicular to the base portion  46   a , with the core polar surfaces  18  being respectively formed on the end surfaces of the arm portions  46   b . The core  46  may be formed by, e.g., punching a magnetic steel plate into a predetermined shape and thereafter bending the punched material into a U-shape. 
     The bobbin  48  is an electrical insulating resinous mold, and is integrally and fixedly attached to the core  46  by, e.g., placing the core  46  as an insert in a mold (not shown) during the molding of the bobbin. The bobbin  48  integrally includes an intermediate portion  48   a  for covering most of the base portion  46   a  of the core  46 , a pair of end portions  48   b  for covering most of the arm portions  46 b of the core  46 , and a pair of flange portions  48 c formed in interconnecting regions between the intermediate portion  48   a  and the end portions  48   b . The coil  50  is wound on the intermediate portion  48   a  of the bobbin  48  in a symmetrical arrangement with respect to a center line  46   c  extending in a lateral direction of the core  46 , and is securely held between the flange portions  48   c . The arm portions  46   b  of the core  46  extend through the end portions  48   b  of the bobbin  48  to project upward therefrom, so that the pair of core polar surfaces  18  are arranged symmetrically, in a same virtual plane, with respect to the center line  46   c  of the core  46 . 
     Further, a pair of terminals  52  (FIG. 3) connected with the coil  50  are integrally provided by, e.g., an insert molding process, in one end portion  48   b  of the bobbin  48 . The terminals  52  are fixedly connected by, e.g., a welding process to the pair of coil terminals  44  built in the upper plate member  30 , when the electromagnet  14  is accommodated in a space between the upper plate member  30  and the bottom plate member  32  of the base  12 . 
     The armature  22  is a flat plate-like member formed by, e.g., punching a magnetic steel plate into a predetermined shape, and is provided with the abutting surfaces  20  respectively formed in longitudinal opposite end regions in one surface of the armature (a lower surface in FIG.  1 ). As shown in FIGS. 6 and 7, the armature  22  has a symmetric shape with respect to a pivoting center  22   a  located at a longitudinal center of the armature, and is embedded at the intermediate region  22   b  defined between the abutting surfaces  20  into an insulating member  54  having likewise a symmetric shape. The armature  22  is integrally coupled to the two conductive plate springs  24 , via the insulating member  54 , in a mutually insulated condition. 
     The insulating member  54  is an electrically insulating resinous mold, and is integrally and fixedly attached to the armature  22  and the two conductive plate springs  24  by, e.g., placing the armature  22  and the conductive plate springs  24  as inserts in a mold (not shown) when molding the insulating member. A rectangular through hole  56  capable of receiving the permanent magnet  16  is formed in the insulating member  54  at the center of the bottom surface  54   a thereof opposing the upper plate member  30  of the base  12 . The permanent magnet  16  in the shape of generally rectangular plate is magnetized in the direction of thickness so as to provide different poles for the upper and lower faces thereof, and is securely fitted due to its own magnetic attractive force to the center portion of the armature  22  exposed inside the through hole  56  of the insulating member  54 . The insulating member  54  is further provided, at the longitudinal center thereof on both lateral sides of the through hole  56 , with a pair of seats  58  for respectively receiving a pair of supports  36  protruding on the upper plate member  30  of the base  12 . Therefore, a line linking the seats  58  substantially coincides with the pivoting center  22   a  of the armature  22 . 
     Although, in the illustrated embodiment, the permanent magnet  16  is constructed to pivot or rotate together with the armature  22  as described above, the present invention is not limited to this construction, and it is also possible to adopt the construction in which a permanent magnet is fixedly placed on the upper plate member  30  of the base  12 . In this arrangement, the permanent magnet is magnetized in a longitudinal direction so as to provide the longitudinal center portion thereof with a pole different from the poles of the longitudinal opposite end portions located adjacent to the core polar surfaces  18 . 
     Each conductive plate spring  24  is a thin plate member formed by, e.g., punching a copper plate into a predetermined shape, and carries the movable contacts  26  respectively on first surfaces (lower surfaces in FIG. 6) of movable spring portions  60  formed at longitudinal opposite ends of the plate spring. The movable contacts  26  constitute make contacts  26 a and break contacts  26 b respectively corresponding to the make contacts  28   a  and the break contacts  28 b of the fixed contacts  28  provided on the upper plate member  30  of the base  12  (FIG.  7 ). Each movable spring portion  60  is formed into a bifurcate shape, so as to obtain a desired contact pressure at the instant when the contacts are closed. Each conductive plate spring  24  is substantially embedded in the insulating member  54  in an intermediate portion between the movable spring portions  60  at the opposite ends. Consequently, the conductive plate springs  24  are arranged symmetrically with respect to the center line  22   c  linking the abutting surfaces  20  of the armature  22  and disposed side-by-side to be laterally separated from the armature  22 . 
     A hinge spring portion  62  is integrally joined to each conductive plate spring  24  at the center of the intermediate portion thereof, so as to extend laterally from the insulating member  54  along the pivoting center  22   a  of the armature  22 . Each hinge spring portion  62  extends in U-shape toward the make contact  26   a  in relation to the pivoting center  22   a , and terminates on the side of the break contact  26   b . The hinge spring portion is fixed at a distal end  62   a  thereof to the common contact  38  provided on the upper plate member  30  of the base  12  by, e.g., a welding process. 
     In this way, the armature  22  and the two conductive plate springs  24 , integrated through the insulating member  54 , are combined with the base  12  having the assembled structure and containing the electromagnet  14  as described above, by mounting the pair of seats  58  formed on the bottom surface  54   a of the insulating member  54  on the pair of supports  36  protruding on the upper plate member  30  of the base  12 , and by fixing the distal ends  62   a  of the hinge spring portions  62  of the conductive plate springs  24  to the two common contacts  38  provided on the upper plate member  30 . In this arrangement, the movable contacts  26  formed at the opposite ends of each conductive plate spring  24  are disposed opposite to the corresponding fixed contacts  28  provided on the upper plate member  30  of the base  12 . Then, under the interaction of the magnetic flux of the electromagnet  14  and the magnetic flux of the permanent magnet  16 , the armature  22  and the two conductive plate springs  24  pivot or rotate integrally, so as to selectively open or close the make contacts  26   a ,  28   a  and the break contacts  26   b ,  28   b  according to the rotation. In this respect, the conductive plate springs  24  act to selectively conduct the corresponding make fixed contact  28   a  or break fixed contact  28   b  to the common contact  30 , and to bias the armature  22  and the conductive plate springs  24  toward a break side by the respective hinge spring portions  62 . A relay assembly thus assembled in this way is then put into an outer casing  64  as shown in FIG. 1, and a gap formed in the underside of the casing  64  is sealed, so that the polar relay  10  is completed. 
     The polar relay  10  according to the present invention has essentially a characteristic construction for assuring sufficient dimensions for insulation, i.e., sufficient insulating distances, meeting the requirements of IEC60950, as described before, when it is mounted in an information processing apparatus adapted to be connected to a telecommunications channel, such as a modem or a facsimile. 
     Section 2.10.3.2 of IEC60950 (1999) prescribes that dimensions for insulation, required between circuits, should be assured to be 1 mm and more for a commercial alternating supply voltage of 150 V or less, while to be 2 mm and more for a commercial alternating supply voltage of over 150 V and not greater than 300 V. In order to meet these requirements, the polar relay  10  is constructed in such a manner that a maximum distance between the movable contact  26  and the fixed contact  28 , capable of coming into contact with each other, (i.e., an open-contact distance) is 1 mm and more during the travel of the armature  22 . Conventionally, in a small size, low power-consumption type polar relay having a balanced-armature structure, an open-contact distance has been held in the order of 0.3 mm to 0.5 mm. On the other hand, the polar relay  10  according to the present invention is capable of assuring the open-contact distance of 1 mm and more while maintaining the small size/low power-consumption properties thereof, by adopting various characteristic constructions as described below. 
     First, in order to increase the insulation distances, required between opened or broken contacts, the polar relay  10  has features wherein the travel (i.e., the pivoting angle) of the armature  22  is increased in comparison with a conventional polar relay, while the thickness (i.e., the dimension in a pivoting direction) of opposite end regions of the plate-like armature  22  is gradually decreased toward the longitudinal ends of the armature  22 , so that both of the pair of abutting surfaces  20  of the armature  22  are formed as inclined surfaces with respect to a major plane  22   d  (FIG.  8 B). On the other hand, the pair of core polar surfaces  18  of the electromagnet  14  have a shape as punched from a magnetic steel plate, and therefore are formed as horizontal faces substantially parallel with the major plane  22   d  of the armature  22  located in a balanced position. As will be described later, the abutting surface  20  as the inclined surface is formed so as to reduce the angle between opposed surfaces at the time of being mutually abutted to or contact with the core polar surface  18 , as much as possible. 
     As shown schematically in FIGS. 8A to  8 C, as a result of increasing of the travel T of the armature  22 , for example, a spatial distance between the make movable contact  26   a  and the make fixed contact  28   a  is increased in comparison with a conventional polar relay (FIG. 8A) when the armature  22  is not operated (i.e., the break contacts are closed), so that sufficient insulation distances can be assured (FIG.  8 B). Although not shown, spatial distance between the break movable contact  26   b  and the break fixed contact  28   b , when the armature  22  is operated (i.e., the make contacts are closed), is also increased in a similar way. In this respect, as shown in FIG. BC, each abutting surface  20  of the armature  22  is formed as the inclined surface for reducing the angle between opposed surfaces at the time of being mutually abutted to the core polar surface  18  as much as possible, so that the dimension of a gap defined between the abutting surface  20  and the core polar surface  18 , at the time when the make movable contact  26   a  and the make fixed contact  28   a  are closed, is reduced as much as possible. As a result, although the travel T of the armature  22  is increased, a magnetic resistance, at the time when the make contacts are closed, is reduced, and a magnetic attractive force is thereby prevented from decreasing. Also, in this construction, the thickness of the opposite end regions of the armature  22  is gradually reduced, so that the decrease of a magnetic attractive force generated by the electromagnet  14  for operating the armature  22  is kept to a minimum. 
     Further, the armature  22  is constructed such that the relation a α≦β holds, where a is the inclination angle of each abutting surface  20  with respect to the major plane  22   d  of the armature  22  (FIG. 8B) and β is the angle between the major plane  22   d  of the armature  22  and each core polar surface  18  at the time of being mutually abutted (FIG.  8 C). With this dimensional relationship, the armature  22  always passes, during the pivoting motion thereof, a position where each of the abutting surfaces  20  oppositely faces the corresponding core polar surface  18  in parallel with each other. Since the position where the abutting surface  20  oppositely faces the core polar surface  18  in parallel with each other is the most efficient position at which the magnetic attractive force is exerted uniformly over the entire abutting surface  20 , it is ensured, by realizing the above abutment relationship, that the armature  22  always passes this most efficient position and thereby operates stably. 
     Also with this construction, when the armature  22  comes into abutment to or contact with the core polar surface  18 , the abutting surface  20  is abutted, as shown in FIG. 9A, at least to the outer corner portion  18   a  of the core polar surface  18  in relation to the pivoting center  22   a . As a result, during the time when the abutting surface  20  of the armature  22  is abutted to the core polar surface  18 , a magnetic flux reaches a region near the end of the armature  22 , so that it is also possible to efficiently generate a magnetic attractive force over the entire abutting surface  20 . On the contrary, in the case where the abutting surface  20  comes into abutment, as shown in FIG. 9B, with the inner corner portion  18   b  of the core polar surface  18 , a magnetic flux does not reach the end region of the armature  22 , so that it is difficult to generate a magnetic attractive force efficiently over the entire abutting surface  20 . 
     Further, in the above construction, since the abutting surface  20  of the armature is formed as the inclined surface, it is possible to bring the position of the corresponding core polar surface  18  closer to the abutting surface  20  as compared to the case where the abutting surface is formed in parallel with the major plane  22   d  (shown by a broken line in FIG.  8 C). As a result, it is possible to keep the increase of the overall height of the finished product of the polar relay  10  due to the enlargement of the travel T of the armature  22  to a minimum. 
     The abutting surface  20  of the armature  22  can be formed by, e.g., a pressing process, as the inclined surface having the desired angle a. Also, instead of, or in addition to, forming the abutting surface  20  as the inclined surface, the core polar surface  18  of the electromagnet  14  may post-machined to be formed as an inclined surface that is inclined with respect to the major plane  22   d  of the armature  22  located in the balanced position. In this case, the structure is also advantageous in that the angle between opposed surfaces at the time when the abutting surface contacts with the core polar surface is reduced as much as possible, and in that the armature  22  passes, during the pivoting motion thereof, a position where the abutting surface  20  oppositely faces the corresponding core polar surface  18  in parallel with each other. 
     Incidentally, when the polar relay  10  is to be constructed as a self-reset relay capable of automatically shifting, at the time of non-excitation of the electromagnet  14 , from a make-contacts closing state to a break-contacts closing state, it is necessary to construct it in such a manner that a magnetic attractive force exerted by the permanent magnet  16  between the core polar surfaces  18  of the electromagnet  14  and the abutting surfaces  20  of the armature  22  during the time when a magnetomotive force is 0 A, is smaller in the make side than in the break side. For this purpose, it is advantageous, as shown in FIG. 10, to form a non-magnetic layer  66  on the abutting surface  20  in the make side of the armature  22 . The non-magnetic layer  66  can be formed by, e.g., welding non-magnetic material such as copper or stainless steel onto the surface of the armature  22 . 
     In the above construction, in order to accurately adjust the magnetic attractive force on the make side, it is desirable to form the non-magnetic layer  66  with a uniform thickness over the entire abutting surface  20  of the armature  22 . However, if the abutting surface  20  of the armature  22  is formed into the inclined surface by a pressing process as described above after forming the non-magnetic layer  66  on the abutting surface  20 , the thickness of the non-magnetic layer  66  would also become gradually thinner toward the longitudinal end of the armature  22 . Alternatively, if the non-magnetic layer  66  is post-processed to be welded onto the abutting surface  20  as the inclined surface, welding failure would tend to occur, which makes stable forming difficult. 
     Thus, in the polar relay  10 , the armature  22  is manufactured by the following characteristic method. First, as shown in FIG. 11A, a magnetic plate  69  is provided, which includes a first flat surface  67  and a second surface  68  consisting of a major flat-face portion  68   a  parallel with the first surface  67  and an inclined-face portion  68   b  crossing at an obtuse angle with the major portion  68   a  and extending in a direction gradually approaching the first surface  67 . The inclined-face portion  68   b  of the magnetic plate  69  is previously provided with a construction (dimensions, shape, angle, etc.) to coincide with that of the abutting surface  20  of the armature  22  to be manufactured. Then, the non-magnetic layer  66  with a uniform thickness t is formed in a region of the first surface  67  of the magnetic plate  69  situated on the opposite side of the inclined-face portion  68   b.    
     Then, the second surface  68  of the magnetic plate  69  is oriented to be opposed to a flat supporting surface S and the magnetic plate  69  is fixedly placed on the supporting plane S. In this condition, the region containing the non-magnetic layer  66  in the first surface is pressed with a pressure P. Thereafter, the magnetic plate  69  is deformed until a desired surface region of the non-magnetic layer  66  takes the mirror image shape of the inclined-face portion  68   b  formed on the second surface  68 , and, as a result, the inclined-face portion  68   b  shifts into a plane common to the major flat-face portion  68   a . During this process, the pressed region of the magnetic plate  69  displaces the material thereof without changing its own thickness, so that the thickness t of the non-magnetic layer  66  is also maintained in an entirely uniform condition. In this way, an inclined face, having the non-magnetic layer  66  with a uniform thickness, is formed on the first surface  67  of the magnetic plate  69  (FIG.  11 B). Since the shape of the inclined face having the non-magnetic layer  66  coincides with the shape of the abutting surface  20  of the armature  22 , the armature  22  including the inclined abutting surface  20  having non-magnetic layer  66  with an entirely uniform thickness is manufactured by cutting off the excess portion of the magnetic plate  69  along a solid line A. 
     Now, the approximate dimensions of various components in the specific embodiment of the construction described above will be enumerated below. Referring to FIG. 12, the above construction is realized, wherein the longitudinal overall length L of the armature  22  is 17.8 mm (L=17.8 mm), the distance D between the pivoting center  22   a  of the armature  22  and the outer corner portion  18   a  of the core polar surface  18  is 8.6 mm (D=8.6 mm), the difference in height H 1  between the core polar surface  18  and the pivoting center  22   a  is 1.27 mm (H 1 =1.27 mm), the difference in height H 2 , at a position 8.6 mm distant from the pivoting center  22   a , between the abutting surface  20  and the major plane  22   d  is 0.2 mm (H 2 =0.2 mm), the thickness t of the nonmagnetic layer  66  in the abutting surface  20  in the make side is 1.0 mm (t=1.0 mm), and the inclination angle α of each abutting surface  20  is approximately 7.7° (α=approximately 7.7°). In this arrangement, the armature  22  pivots over an angle of approximately 9.9° about the pivoting center  22   a , and each abutting surface  20  comes into abutment with the outer corner portion  18   a  of the corresponding core polar surface  18 . 
     As another measure for constructing the polar relay  10  as a self-reset relay, the permanent magnet  16  fixed to the lower surface of the armature  22  may be disposed at a position deviated toward the break side with respect to the pivoting center  22   a , as diagrammatically shown in FIG.  13 . In this arrangement, a magnetic flux from the permanent magnet  16  is greater at the core polar surface  18  in the break side than at the core polar surface  18  in the make side, so that it is possible to lower the magnetic attractive force in the make side to a level smaller than that in the break side during the time when a magnetomotive force is 0 A. This construction may be adopted in place of, or in addition to, the above-described construction wherein the non-magnetic layer  66  is formed on the abutting surface  20 . 
     Next, in the case of a dual-circuit type polar relay  10 , it is required that, between two conductive plate springs  24  disposed side-by-side in respective both sides of the armature  22 , sufficient insulation distances are assured between the movable make contacts  26   a  as well as between the movable break contacts  26   b  thereof. However, when the travel of the armature  22  is increased in order to increase the insulation distances required between the opened contacts as already described, it is necessary to provide a relatively thin and long meandering shape (FIG.  7 ), capable of generating a desired spring force, to the hinge spring  62  for biasing the armature  22  toward the break side. If the insulation distances are to be assured, in this construction, between the corresponding contacts arranged side-by-side in two conductive plate springs  24  against, especially, the short-circuit through the armature  22 , the spatial distance between the armature  22  and each conductive plate spring  24  is increased. Thus, due to the shapes of the hinge springs  62  projecting laterally in both sides of the armature  22 , there is a fear of an increase in the overall dimension in the lateral direction of the polar relay  10 . 
     Therefore, the polar relay  10  is constructed in such a manner that, as shown in FIG. 7, the insulating member  54  integrating the armature  22  and two conductive plate springs  24  includes a pair of extensions  70  extending toward the longitudinal opposite end regions of the armature  22  so as to cover most of the intermediate region of the armature  22 . These extensions  70  integrally extend from the longitudinal opposite end surfaces  54   b  of the insulating member  54 , from which the longitudinal opposite end regions of each conductive plate spring  24  project, along the intermediate portion  22   b  of the armature  22 , and act so as to increase the insulation distances, as a creepage distance, required between the longitudinal end regions of the armature  22  and the longitudinal end regions of each conductive plate spring  24 , both exposed outside the insulating member  54 . Thus, as shown in the drawing, each conductive plate spring  24  can be formed in a shape such that it gradually approaches the extensions  70  of the insulating member  54  at a length within the range from the movable spring portion  60  at the opposite ends to the end surfaces  54   b  of the insulating member  54 . That is, each conductive plate spring  24  is disposed so as to have a lateral space between the proximal end portions  24   a  projecting from the end surfaces  54   b  of the insulating member  54  and the extensions  70  of the insulating member  54  smaller than a lateral space between the movable contacts  26  and the abutting surfaces  20  of the armature  22 . In this arrangement, sufficient insulation distances required between the exposed portion of each conductive plate spring  24  and the exposed portion of the armature  22 , is also assured as a spatial distance (or a clearance) and as a creepage distance. 
     According to this construction, even when two conductive plate springs  24  have such configurations that the space between the intermediate portions thereof is less than the space between the movable spring portions  60  as shown in the drawing, it is possible to assure sufficient insulation distances, required against a short-circuit, between the contacts of the conductive plate springs  24  and especially through the armature  22 . In this respect, although the hinge spring  62  projecting from the longitudinal center of each conductive plate spring  24  to a lateral side of the armature  22  has a relatively thin and long meandering shape, it is possible to suppress the increase of the whole lateral dimension of the finished product of the polar relay  10  because of the narrower space between the intermediate portions of the conductive plate springs  24 . 
     The above arrangement is especially advantageous in the construction wherein the armature  22  has the inclined abutting surfaces  20  as already described. In this construction, the thickness (the dimension in a pivoting direction) of the intermediate region  22   b  of the armature  22 , embedded in the insulating member  54 , is larger than the thickness of the opposite end regions including the abutting surfaces  20 , so that it is possible to define the dimension of the armature  22  in the lateral direction perpendicular to the pivoting direction in such a manner that the intermediate region  22   b  is smaller than the opposite end regions, as long as the magnetic flux density through the armature  22  is not affected. Therefore, it is possible to significantly reduce the space between the intermediate portions of two conductive plate springs  24  in comparison with the space between the movable spring portions  60 , which contributes to a size reduction of the polar relay  10 . 
     Next, in order to assure insulation distances required between contacts and a coil, the polar relay  10  adopts a construction capable of assuring sufficient insulation distances required against not only an indirect short-circuit between the contacts  26 ,  28  and the coil  50  via the core  46  of the electromagnet  14  and the armature  22  but also a direct short-circuit between the contacts  26 ,  28  and the coil  50 . First, for the indirect short-circuit, combined portions are provided to the upper plate member  30  of the base  12  interposed between the armature  22  and the coil  50  of the electromagnet  14  as well as to the bobbin  48  of the electromagnet  14 , so as to be complementarily combined with each other at a position between a pair of core polar surfaces  18  of the core  46  and the coil  50 . Thereby, the upper plate member  30  and the bobbin  48  cooperate with each other to increase the insulation distances required between the core polar surfaces  18  and the coil  50 . 
     More specifically, as shown in FIGS. 4,  5 ,  14  and  15 , a groove  72  is formed on the bobbin  48  of the electromagnet  14  to extend in the lateral direction of the electromagnet  14 , at a location between each end portion  48   b  covering most of each arm portion  46   b  of the core  46  and each flange portion  48   c  provided in the interconnection of the intermediate portion  48   a  with each end portion  48   b  . Also, grooves  74  are formed on each end portion  48   b  to communicate with the groove  72 , at locations in the respective lateral sides of the arm portion  46   b  of the core  46 . On the other hand, plate walls  76 ,  78  are formed on the upper plate member  30  of the base  12  to project toward the inner space between the upper plate member  30  and the bottom plate member  32 , at positions respectively corresponding to the grooves  72 ,  74  of the bobbin  48 , and having shapes and dimensions allowing insertion into the grooves  72 ,  74 . Thus, when the upper plate member  30  is combined with the bottom plate member  32  while containing the electromagnet  14  within the inner space thereof as already described, the plate walls  76 ,  78  of the upper plate member  30  are respectively received in and complementarily combined with the corresponding grooves  72 ,  74  of the bobbin  48 , thereby enclosing the exposed parts of the respective arm portions  46 b of the core  46  from three sides. According to this complementary combination structure, it is possible to assure a sufficient creepage distance between the core polar surfaces  18  and the coil  50  without substantially increasing the external dimensions of the polar relay  10 . 
     In connection with the above construction, overhangs  80  are formed on the core  46  of the electromagnet  14  to slightly project outward from the surfaces of both end portions  48   b  of the bobbin  48 , at locations near the core polar surfaces  18  at the ends of a pair of arm portions  46   b  (FIG.  4 ). These overhangs can be effectively used, in the molding process of the bobbin  48  with the core  46  being placed as an insert, as supporting sections for positioning and supporting the core  46  at a predetermined position in a mold (not shown). According to this construction, the bobbin  48  is molded so as to cover substantially entirely the core  46 , except for a pair of core polar surfaces  18  and regions surrounding the core polar surfaces  18  including the overhangs  80 . As a result, it is possible to surely insulate the core  46  from the coil  50 , merely by adopting the above construction for increasing the insulation distances required between the core polar surfaces  18  and the coil  50 . 
     For the direct short-circuit between the contacts and the coil, combined portions are provided to the upper plate member  30  as well as to the bottom plate member  32  of the base  12 , so as to be complementarily combined with each other at positions between a plurality of terminals  40 ,  42 ,  44  built into the upper plate member  30  and the coil  50  of the electromagnet  14 . Thereby, the upper plate member  30  and the bottom plate member  32  cooperate with each other to increase the insulation distances required between the terminals  40 ,  42 ,  44  having respectively the fixed contacts  28  and the common contacts  38  and the coil  50 . More specifically, as shown in FIGS. 16 and 17, the bottom plate member  32  of the base  12  is provided with a bottom plate  82  covering the lower surface of the coil  50  and a pair of side plates  84  extending integrally upward from the both side edges extending in the longitudinal direction of the bottom plate  82  to cover the opposite sides of the coil  50 . On the other hand, the upper plate member  30  of the base  12  is provided with an upper plate  86  covering the upper surface of the coil  50  and a pair of side plates  88  extending integrally downward from the both side edges extending in the longitudinal direction of the upper plate  86  to be disposed via gaps along the both sides of the coil  50 . Thus, when the upper plate member  30  is combined with the bottom plate member  32  while containing the electromagnet  14  within the inner space thereof as already described, the side plates  84  of the bottom plate member  32  are respectively received in and combined complementarily with the gaps between the respective side plates  88  of the upper plate member  30  and the coil  50 , and thereby covering entirely the opposite sides of the coil  50 . According to this complementary combination structure, it is possible to assure a sufficient creeping distance between the plural terminals  40 ,  42 ,  44  and the coil  50  without substantially increasing the external dimensions of the polar relay  10 . 
     In connection with the above construction, a sealant  92  may be applied to the complementarily combined portions of the upper plate member  30  and the bottom plate member  32 , for sealing gaps (as denoted by, e.g., a numeral  90  in FIG. 17) formed in the combined portions (see FIG.  18 ). The sealant  92  is made of, e.g., an epoxy-base adhesive, and seals the gaps exposed on the external surface of the polar relay  10  as a finished product, whereby serving to increase the dielectric strength of the complementarily combined portions and to improve the air-tightness of the polar relay  10 . 
     Further, in the polar relay  10 , as a counter measure against an indirect contact/coil short-circuit, insulating surface zones  94  are provided between the pair of core polar surfaces  18  of the electromagnet  14 , exposed on the upper surface of the upper plate member  30  of the base  12 , and the plural fixed contacts  28 , so as not to be exposed to each of the fixed contacts  28 . In the illustrated embodiment, as shown in FIGS. 2 and 15, a pair of walls  96  projecting upward from the upper surface of the upper plate member  30  are formed respectively between each of the pair of openings  34  of the upper plate member  30  and two fixed contacts  28  neighboring them, and the mutually opposed surfaces of the walls  96  constitute the insulating surface zones  94 . 
     As diagrammatically shown in FIG. 19A, the insulating surface zone  94  formed by the wall  96  is located at a position where it is not easily affected by scattered metal particles due to the abrasion of the fixed contacts  28  or material carbonization due to arc discharges. Therefore, the insulating surface zone  94  serves to reinforce the function of the wall  96  increasing the creeping distance between the core polar surface  18  and the fixed contact  28 , and to prevent the deterioration of dielectric strength between the core and the contacts. In this respect, as shown in FIG. 19B, a similar operative effect can be obtained by providing a groove  98  in the upper plate member  30 , instead of the walls  96 , to be recessed at a location between the core polar surface  18  and the fixed contact  28 , so as to form an insulating surface zone  94  inside the groove  98 . 
     As will be appreciated from the above description, according to the present invention, it becomes possible, in a polar relay of a balanced-armature type, to surely establish sufficient insulation distances required between opened or broken contacts as well as sufficient insulation distances required between contacts and a coil, without increasing external dimensions of the finished product. Further, in a double-circuit polar relay of a balanced-armature type, it becomes possible to surely establish sufficient insulation distances required between contacts arranged side-by-side, without increasing external dimensions of the finished product. Therefore, the polar relay according to the present invention is capable of assuring, by its own structure, sufficient insulation distances meeting the requirements of IEC60950, when it is mounted in an information processing apparatus adapted to be connected to a telecommunications channel. 
     FIG. 20 is a schematic circuit diagram showing the construction of an information processing apparatus  100  including the polar relay  10 , according to an embodiment of the present invention. The information processing apparatus  100  has the construction of a data processing section of a facsimile incorporating a telephone function therein, and includes a data processing circuit  106  electrically connected via an isolating transformer  104  to a telephone circuit  102  as one example of a telecommunications channel, and a signal generating circuit  108  insulated from the telephone circuit  102  by the polar relay  10 . The polar relay  10  is arranged so that the make contacts  28   a  are connected to the signal generating circuit  108 , the break contacts  28   b  are connected to the telephone circuit  102 , and the common contacts  38  are connected to a telephone  110 . 
     The information processing apparatus  100  usually transmits or receives a facsimile signal between the data processing circuit  106  and the telephone circuit  102 . For example, when a facsimile signal is received from the telephone circuit  102 , the data processing circuit  106  performs a facsimile reception process without ringing the bell of the telephone  110 . The telephone  110  is usually connected to the telephone circuit  102  through the polar relay  10 , so as to permit speech transmission from the telephone  110 . In this arrangement, when a telephone signal is received from the telephone circuit  102 , the data processing circuit  106  first recognizes a telephone reception, and, immediately after the recognition, excites a relay driver  112  to operate the polar relay  10 , because a bell-starting signal from the telephone circuit  102  terminates in the meantime. Thereby, the connection of the telephone circuit  102  with the telephone  110  is cut off, and the signal generating circuit  108  is connected to the telephone  110  through the polar relay  10 , so as to send the bell-starting signal from the signal generating circuit  108  to the telephone  110 . Immediately after the telephone  110  becomes ready for receiving, the data processing circuit  106  resets the polar relay  10  by the relay driver  112 . Consequently, the telephone  110  is again connected to the telephone circuit  102 , and thereby enabling two-way communication. 
     In the information processing apparatus  100  having the above construction, it is necessary to insulate the telephone circuit  102  from the data processing circuit  106  and the signal generating circuit  108  by the insulation distances prescribed in IEC60950. In this respect, the polar relay  10  assures the open-contact distance of 1 mm and more, capable of meeting the requirements of IEC60950, while maintaining the small size and low power-consumption properties inherent in the balanced-armature type polar relay, as already described. Therefore, in the illustrated con figuration, the polar relay  10  surely insulates the telephone circuit  102  from the signal generating circuit  108  by the insulation distances meeting the requirements of IEC60950. Consequently, it is no longer necessary to interpose an insulating transformer or any other insulating elements between the signal generating circuit  108  and the telephone circuit  102 , which facilitates a further reduction in size of the information processing apparatus  100 . 
     FIG. 21 is a schematic circuit diagram showing the construction of an information processing apparatus  114  including the polar relay  10 , according to another embodiment of the present invention. The information processing apparatus  114  has the construction of a data processing section of a general circuit/Internet convertible telephone, and includes a voice data processing circuit  116  insulated by the polar relay  10  from a telephone circuit  102  as one example of a telecommunications channel. The polar relay  10  is arranged so that the make contacts  28   a  are connected to the voice data processing circuit  116 , the break contacts  28   b  are connected to the telephone circuit  102 , and the common contacts  38  are connected to a telephone  110 . The voice data processing circuit  116  is connected to Internet  118 . 
     The information processing apparatus  114  usually connects the telephone  110  to the telephone circuit  102  through the polar relay  10 , and thereby enabling a two-way communication. In this arrangement, when the telephone  110  is used as an internet phone, the relay driver  112  is excited in response to a user&#39;s request to operate the polar relay  10 . Thereby, the connection between the telephone circuit  102  and the telephone  110  is cut off, and the voice data processing circuit  116  is connected to the telephone  110  through the polar relay  10 . Consequently, voice data input to or output from the telephone  110  are suitably processed by the voice data processing circuit  116 , so as to be transmitted or received by the Internet  118 . 
     In the information processing apparatus  114  having the above construction, it is necessary to insulate the telephone circuit  102  from the voice data processing circuit  116  by the insulation distances prescribed in IEC60950. In this respect, the polar relay  10  functions similarly in the information processing apparatus  110  as described above, and thus surely isolates the telephone circuit  102  from the voice data processing circuit  116  by the insulation distances meeting the requirements of IEC60950. As a result, it is no longer necessary to interpose an isolating transformer or any other insulating element between the voice data processing circuit  116  and the telephone circuit  102 , which facilitates the further reduction in size of the information processing apparatus  114 . Please note that the information processing apparatus  114  may be installed into a switching system equipped in a building, instead of a desk-top type general circuit/Internet convertible telephone. 
     Thus, according to the present invention, a miniature information processing apparatus of a low power-consumption type is provided that is capable of assuring sufficient insulation distances, meeting the requirements of IEC60950, when it is connected to a telecommunications channel. 
     While certain preferred embodiments according to the present invention have been described above, the present invention is not limited to these embodiments, but various changes and modifications may be made within the scope of the appended claims. For example, in order to meet the requirements of IEC60950, it is desirable that a single polar relay adopts all of the above-described various insulation measures in the polar relay. However, depending upon the application of the polar relay, only desired one of these measures may be adopted, or two or more measures may be adopted in a desired combination. All insulation measures, except for those requiring that the base has a combination structure as presupposition, may be adopted in a polar relay in which an electromagnet is integrally incorporated into a base through an insert molding process. Similarly, all insulation measures except for those requiring that the polar relay has a double-circuit structure as presupposition, may be adopted in a single-circuit type polar relay. Further, the polar relay according to the present invention may be mounted, for the purpose of insulation between the circuits, in various information processing apparatus such as a facsimile having a recorder function, a voice modem, etc., other than the above-described facsimile with a telephone function or a general-circuit/Internet convertible telephone.