Patent Publication Number: US-6340801-B1

Title: Rotary encoder and multi-operational electronic component using the same

Description:
FIELD OF THE INVENTION 
     The present invention relates to a rotary encoder that generates a signal detecting the amount of change, i.e. rotational angle in rotation and rotating direction during rotational operation, and multi-operational electronic component, such as a mouse for a PC and a cellular phone, using the rotary encoder. 
     BACKGROUND OF THE INVENTION 
     FIG. 14 shows a plan view of the contact portion of a conventional rotational type encoder (hereinafter referred to simply as RTE), which generates an electric signal detecting the amount of change (rotational angle) in rotation and rotating direction during rotational operation. rotational contact plate  1  rotatably mounted on base  5 , and three flexible sliding bars  6 ,  7 ,  8  extended from base  5 . 
     Rotational contact plate  1  has rotary contact  2  formed typically by insertion molding on the surface of an insulation resin-made circular board. Rotary contact  2  includes common annular contact  3  and teeth-shaped contact  4  for signal generating, with each tooth angled uniformly and extended radially from annular contact  3 . 
     Flexible sliding bars  6 ,  7 , and  8  have elastic contacts  6 A,  7 A, and  8 A on each tip of the bars, respectively. 
     As shown in FIG. 14, elastic contacts  6 A,  7 A, and  8 A are arranged parallel in a radial direction of rotary contact  2 , and contact with rotary contact  2 . Elastic contacts  6 A contacts with annular contact  3 , while elastic contacts  7 A,  8 A contact with teeth-shaped contact  4 . On rotational contact plate  1 , the contact spot of elastic contact  7 A is displaced from that of contact  8 A by “D” (indicated in FIG. 14) in a rotating direction of contact plate  1 . 
     Following the rotating operation of plate  1 , contact  6 A slides resiliently on annular contact  3 , and contacts  7 A and  8 A slide resiliently on teeth-shaped contact  4 . As contact plate  1  rotates, electric signals having a rectangular wave, as shown in FIG. 15, are generated between contacts  6 B and  7 B,  6 B and  8 B. In FIG. 15, the rotational angle of plate  1  is described on the horizontal axis. Suppose that an electric signal generated between contacts  6 B and  7 B is designated as signal “M”, while an electric signal generated between contacts  6 B and  8 B is designated as signal “N”. In the prior art, the rotational angle and the rotating direction have been detected according to the number of signals “M” and “N”, and the phase difference (i.e., the angle difference) “T” between the two signals. 
     FIG. 16 shows a general perspective view of a rotary encoder with a push switch (hereinafter referred to simply as REPS), which functions as a multioperational type electronic component employing the RTE described above. FIG. 17 is a cross-sectional side view of the REPS shown in FIG.  16 . As shown in FIGS. 16 and 17, RTE  12  is disposed on one side of mounting substrate  11  serving as a base, on the other side of substrate  11 , self-restoring type push switch (hereinafter referred to simply as PS)  13  is disposed. RTE  12  is held on substrate  11  in a manner that it is movable in a vertical direction (indicated by arrows “V” in FIGS. 16 and 17.) On the other hand, PS  13  is fixed to substrate  11  so as not to move. FIG. 18 shows a general perspective view of mounting substrate  11 . 
     As shown in FIG. 18, resin-made substrate  11  is provided with: 
     recess  15  having guide rails  14  for RTE  12  to move along; 
     recess  16  for fixing PS  13 ; and 
     three contact plates  18  ( 18 A,  18 B,  18 C) having their respective three terminals  17  ( 17 A,  17 B,  17 C) for leading electric signals of RTE  12  to the outside. 
     As shown in FIG. 17, RTE  12  is held by recess  15  in substrate  11  and guide rails  14  in a manner that it is movable in a vertical direction indicated by the arrow “V”. 
     As described above, RTE  12  comprises: 
     rotary contact  20 A including an annular contact portion, and a teeth-shaped contact portion arranged outside of the annular contact portion, which is mounted on an inner surface of cylindrical operating knob  19 ; and 
     three flexible sliding bars  22 A,  22 B, and  22 C extended in parallel from resin-made substrate  21 . 
     Operating knob  19  is retained with substrate  11  in a manner that it is rotatable on cylindrical shaft  23 . Each elastic contact of three sliding bars  22 A,  22 B,  22 C connects resiliently with rotary contact  20 A, having a parallel arrangement in a radial direction of rotary contact  20 A. 
     Furthermore, three elastic contact legs  24  having electrical continuity with their respective elastic contact bars  22 A,  22 B,  22 C, which protrude in an opposite direction from substrate  21 , connect resiliently with three contact plates  18  ( 18 A,  18 B,  18 C). 
     On the other hand, as shown in FIG. 17, PS  13  is fitted in recess  16  in substrate  11  so as not to move. Actuating button  25  of PS  13  is in contact with pushing portion  23 A of cylindrical shaft  23  and pushes it up. Switching terminal  26 , which transmits the electric signal from PS  13  to the outside, projects downwardly from substrate  11 . 
     FIG. 19 is a partially sectioned side view depicting an example in which the REPS is mounted in an end-use apparatus. As shown in FIG. 19, leg  11 A disposed on the bottom of substrate  11 , terminal  17  of RTE  12 , and switching terminal  26  of PS  13  are inserted into mounting holes  28  and  29  in wiring board  27  of the apparatus, and soldered. In this way, the REPS is mounted in an apparatus. Periphery  19 A of operating knob  19 , serving as an operating portion, protrudes from upper enclosure  30  of the apparatus. 
     The REPS of the prior art constructed as above operates in a manner, which will be described hereinafter. 
     First, RTE  12  will be described. 
     An operator rotates cylindrical operating knob  19  by applying a force on periphery  19 A of knob  19  in the tangential direction (indicated by the arrow “H” in FIG.  16 ). This rotary motion causes rotary plate  20  to rotate on cylindrical shaft  23 . According to the rotation, each elastic contact of three flexible sliding bars  22 A,  22 B,  22 C slides on contact  20 A including annular contact portion and teeth-shaped contact portion secured to rotary plate  20 , while maintaining resilient contacts therewith. As a result, RTE  12  generates an electric signal corresponding to the rotating direction of operating knob  19 . This electric signal is transferred to contact plate  18  on mounting substrate  11  from three elastic contacts respectively corresponding to three sliding bars  22 A,  22 B,  22 C. The electric signal is further transferred to a circuit on wiring board  27  of the apparatus through terminals  17  for external connections. 
     Now, the self-restoring PS will be described. 
     The operator applies a depressing force on periphery  19 A of knob  19  in a direction toward the central axis of rotation (i.e., the direction of the arrow “V 1 ” shown in FIG. 19) against the biasing force of actuating button  25  which pushes RTE  12  upward. The depressing force shifts entire RTE  12  in the direction of the arrow “V 1 ” along guide rails  14  of substrate  11 . This movement causes pushing portion  23 A of cylindrical shaft  23  to depress actuating button  25 . The depressed motion of actuating button  25  actuates PS  13  to thereby generate an electric signal. The electric signal is transmitted through switching terminal  26  to the circuit on wiring board  27  in the apparatus. When the depressing force applied on knob  19  is removed thereafter, RTE  12  is pushed back and returns to its original position by a resilient restoring force of PS  13 . This is how the REPS of the prior art operates. 
     However, the RTE of the prior art, as shown in FIGS. 14 and 15, generates two electric signals “M” and “N” for detecting the amount of change (rotational angle) in rotation and rotating direction during rotational operation. For this detection, the prior art has employed the arrangement: three contacts  6 A,  7 A,  8 A of three flexible sliding bars  6 ,  7 ,  8  are placed in a parallel direction of rotary contact  2 , such that common elastic contact  6 A of sliding bar  6  contacts resiliently with annular contact  3 , while two signaling elastic contacts  7 A and  8 A respectively disposed on sliding bars  7  and  8  are in resilient contact with teeth-shaped contact  4  extended from annular contact  3 . For this arrangement, the RTE of the prior art inconveniently needs a large diameter of the entire RTE. Consequently, in the REPS functioned as a multi-operational electric component employing the RTE of the prior art, cylindrical operating knob  19  to operate RTE  12  needs to be made even larger in size. Moreover, the top end of mounting substrate  11  must be kept from protruding beyond upper enclosure  30  when mounting the REPS on the apparatus. Furthermore, a wide space is needed between upper enclosure  30  and wiring board  27  due to the structure in which the bottom surface of substrate  11  mounted on wiring board  27  of the apparatus has to be kept lower than the bottom position where knob  19  reaches. Thus, in the prior art, there has been a problem that an enclosure of the apparatus equipped with the REPS becomes so bulky in height size. 
     SUMMARY OF THE INVENTION 
     The present invention is intended to eliminate the foregoing problems of the past by realizing an RTE having a small-sized diameter, which generates an electric signal to detect the amount of change in rotation and rotating direction during rotational operation. In addition, with the improved RTE, this invention aims at providing a multi-operational electronic component not only having a cylindrical operating knob with small-sized outer diameter, but also having an enclosure of an end-use apparatus with reduced height. 
     The rotary type encoder of the invention comprises: 
     a contact substrate on which three fan-shaped conductive layers having respective leading terminals are disposed such that they are placed on the positions having a same distance from the center of the substrate; and 
     a movable contact plate having three elastic contacts, which have an electrical continuity with each other and are spaced with the radial angle of 120°. The movable contact plate is disposed so as to be rotatable on the center of the contact substrate. 
     Disposed on the positions having a same distance from the center of the contact substrate, the three elastic contacts resiliently contact with the substrate. 
     As the movable contact plate rotates, any two out of three elastic contacts have consecutively electrical continuity with any two out of three fan-shaped conductive layers. The continuity signal is led out from each leading terminal. 
     The three conductive layers on the surface of the contact substrate, each of which has the radial angle of 60°, spaced apart to subtend an angle of 80° at the center of the substrate. 
     With such a structure, three different electric signals are generated between leading terminals of the three conductive layers when the RTE rotates. According to the generated number of the three signals and the generating order, it is possible to detect the amount of change (i.e. rotational angle) in rotation and rotating direction during rotational operation. The three elastic contacts having resilient contacts with the contact substrate are disposed on the positions having a same distance from the center of the substrate. This arrangement allows the RTE to have a smaller diameter. With such downsized RTE, it is possible to provide a multi-operational electronic component not only having a cylindrical operating knob with small-sized outer diameter, but also having an enclosure of an end-use apparatus with reduced height size. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view depicting a contact portion of an RTE of a first preferred embodiment of the present invention. 
     FIG. 2 is a plan view depicting a contact substrate of the RTE shown in FIG.  1 . 
     FIG. 3 is a plan view depicting a movable contact plate of the RTE shown in FIG.  1 . 
     FIG. 4 is a cross-sectional side view of the RTE of the first preferred embodiment of the present invention. 
     FIGS. 5A through 5C are conceptual views indicative of the state of the contact portion when the RTE shown in FIG. 1 rotates. 
     FIG. 6 illustrates waveforms of electric signals generated from the RTE shown in FIG.  4 . 
     FIG. 7 is a general perspective view, partially in section, of the REPS functioned as a multi-operational electronic component of a second preferred embodiment of the present invention. 
     FIG. 8 is a cross-sectional front view of the RTE shown in FIG.  7 . 
     FIG. 9 is a sectional view taken along a line  9 — 9  in FIG.  8 . 
     FIG. 10 is an exploded perspective view of the RTE shown in FIG. 7 . 
     FIG. 11 is a side view of the rotary body indicative of how the movable contact plate is held in the RTE shown in FIG.  7 . 
     FIG. 12 is a cross-sectional front view of the contact block portion of the RTE shown in FIG.  7 . 
     FIG. 13 is a cross-sectional side view depicting the operating state of the PS shown in FIG.  7 . 
     FIG. 14 is a plan view depicting the contact portion of an RTE in the prior art. 
     FIG. 15 illustrates waveforms of electric signals generated from the RTE in the prior art. 
     FIG. 16 is a general perspective view of a prior art REPS functioned as a multi-operational electronic component. 
     FIG. 17 is a cross-sectional side view of the REPS in the prior art. 
     FIG. 18 is a general perspective view depicting a mounting substrate of the RTE in the prior art. 
     FIG. 19 is a side view, partially in section, of an apparatus equipped with the prior art REPS. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Preferred Embodiment 
     FIG. 1 is a plan view depicting of the contact portion of an RTE in accordance with the first preferred embodiment of the present invention. The contact portion of the RTE shown in FIG. 1 comprises contact substrate  31  holding fixed contacts, and movable contact plate  32  holding movable contacts. 
     FIG. 2 is a plan view of contact substrate  31 . Contact substrate  31 , as shown in FIG. 2, includes roughly circular substrate  33  made of insulation resin, and three fan-shaped conductive layers  34 A,  34 B,  34 C formed on the surface of substrate  33 . Three conductive layers  34 A,  34 B, and  34 C are formed from punched thin metal plate, each of which has the radial angle of 60°. As shown in FIG. 2, the conductive layers  34 A,  34 B, and  34 C are formed on substrate  33  by insertion molding, spaced to subtend an angle of 80° at the center of the substrate. Furthermore, the conductive layers  34 A,  34 B,  34 C have first terminal  35 A, second terminal  35 B, third terminal  35 C, respectively. 
     Movable contact plate  32  is formed from flexible thin metallic plate processed by punching and bending. As shown in the plan view of FIG. 3, movable contact plate  32  has three elastic contacts  36 A,  36 B,  36 C having an electrical continuity with each other. The three contacts are at a same distance from the center of substrate  33  and are the radial angle of 120° apart from each other. 
     FIG. 4 is a cross-sectional side view of the RTE of the embodiment. As shown in FIG. 4, the RTE has a combined structure of contact substrate  31  and insulation resin-made rotary body  37  holding movable contact plate  32 . Rotary body  37  is combined with substrate  31  so as to rotate concentrically to the center of substrate  31 . Having such a structure, contact substrate  31  and movable contact plate  32 , as shown in FIG. 1, are concentrically combined. When rotary body  37  rotates, three elastic contacts  36 A,  36 B,  36 C slide on three conductive  25  layers  34 A,  34 B,  34 C, while maintaining resilient contacts with the middle position of the widths of three elastic contacts (indicated by the width “W” in FIG. 2) in a radial direction. 
     The elastic contacts  36 A,  36 B, and  36 C have respectively two flexible legs and contacts. This arrangement aims to obtain a constant steady contact between the elastic contacts and the contact position, i.e., the middle position of the width “W” on the conductive layers. Three elastic contacts  36 A,  36 B, and  36 C also can have another arrangement that they have respectively one leg and contact. In this case, both diameters of contact substrate  31  and movable contact plate  32  can be reduced. 
     In FIG. 4, bearing  39  retains operation shaft  38  for rotating rotary body  37 . In addition, radially undulated portion  39 A is formed on the root surface of bearing  39 . Positioning indentations are disposed at 40° intervals in radially undulated portion  39 A. Flexible thin metal plate-made spring  40  has projection  40 A. Flexible spring  40  is retained by rotary body  37  such that projection  40 A is kept in resilient contact with radially undulated portion  39 A. This structure provides a click feel (tactile response) when operation shaft  39  is rotated. Each time operation shaft  38  stops rotating, projection  40 A rests in an indentation of radially undulated portion  39 A. That is, movable contact plate  32  retained by rotary body  37  stops at the position corresponding to an indentation (hereinafter referred to as a click position) of undulated portion  39 A disposed at 40° intervals on the root surface of bearing  39 . As described above, the rotary type encoder of the embodiment has a click mechanism, a rotation can be stopped at a click position. 
     The RTE of the embodiment constructed as described above operates in a manner, which will be described hereinafter. 
     FIGS. 5A,  5 B,  5 C are conceptual views indicative of the state of the contact portion when the RTE rotates. In the interests of simplicity, the flexible legs and contacts shown in FIGS. 5A,  5 B,  5 C are illustrated, taking a state as an example. FIG. 6 shows the waveforms of electric signals. In FIG. 6, the rotational angle is described on the horizontal axis. 
     FIG. 5A shows that projection  40 A of flexible spring  40  settles into a click position in radially undulated portion  39 A and thereby rotary body  37  stops. 
     FIG. 5A shows the states of each portion of movable contact plate  32 . In FIG. 5A, elastic contact  36 A (indicated by ∘) is on the insulating portion (i.e., substrate  33 ), contact  36 B (indicated by ) contacts with layer  34 A, and contact  36 C (indicated by X) contacts with layer  34 C. With such a state, conductive layers  34 A and  34 C are conducting through movable contact plate  32 . The electric signal is led out from first terminal  35 A and third terminal  35 C. The continuity/non-continuity state in this case is indicated at AI (angle I ) in FIG.  6 . In the state of AI, first and third terminals  35 A,  35 C are conducting, while between second and third terminals, i.e.,  35 B- 35 C, and between first and second terminals, i.e.,  35 A- 35 B, have no continuity. 
     Suppose that operation shaft  38  is rotated clockwise from the state. FIG. 5B shows the state in which rotary body  37  has been rotated by 40° in a clockwise direction from the state shown in FIG.  5 A. By the rotation, projection  40 A of flexible spring  40  is settled, accompanying a click feel, into the next click position in radially undulated portion  39 A. In the state, elastic contact  36 A of movable contact plate  32  is still on the insulating portion (substrate  33 ), elastic contact  36 C maintains contact with conductive layer  34 C. Elastic contact  36 B, however, contacts with conductive layer  34 B, leaving from conductive layer  34 A. Therefore, continuity is established between layers  34 C and  34 B, and its electric signal is led out from third terminal  35 C and second terminal  35 B. On the other hand, there is no longer continuity between layers  34 A and  34 C due to the movement of elastic contact  36 B. The continuity signal in this case is indicated at AII in FIG.  6 . In the state of AII, second and third terminals  35 B,  35 C are conducting, while between first and third terminals, i.e.,  35 A- 35 C, and between first and second terminals, i.e.,  35 A- 35 B, have no continuity. 
     In FIG. 5C, rotary body  37  is rotated by another 40° from the state shown in FIG.  5 B. In this state, elastic contacts  36 A and  36 B bring continuity between layers  34 A and  34 B. The electric signal led out from first terminal  35 A and second terminal  35 B. On the other hand, there is no longer continuity between layers  34 B and  34 C. The continuity signal in this case is indicated at AIII shown in FIG.  6 . In the state of AIII, first and second terminals  35 A,  35 B are conducting, while between first and third terminals, i.e.,  35 A- 35 C, and between second and third terminals, i.e.,  35 B- 35 C, have no continuity. 
     In this way, as rotary body  37  is rotated clockwise, three elastic contacts ( 36 A,  36 B,  36 C) of movable contact plate  32 , at 40° intervals, repeat the states of continuity illustrated in FIGS. 5A,  5 B,  5 C in a round-robin fashion. As a result, rotation of rotary body  37  generates the electric signal shown in FIG.  6 . For example, in one complete rotation of rotary body  37 ,  35 A- 35 C experiences the continuity state and the non-continuity state three times each. Likewise,  35 B- 35 C,  35 A- 35 B experience the two states three times each. 
     As rotary body  37  rotates, the electric signals below are generated. 
     1) The continuity/non-continuity states between first terminal  35 A and third terminal  35 C; 
     2) The continuity/non-continuity states between second terminal  35 B and third terminal  35 C; and 
     3) The continuity/non-continuity states between first terminal  35 A and second terminal  35 B. 
     Rotating rotary body  37  generates the signals in which the two states are regularly repeated with respect to each pair of the terminals. The patterns of each signal&#39;s waveform are out of phase with each other by 40° corresponding to the rotational angle of rotary body  37 . 
     As described above, the RTE of the embodiment has a click mechanism. The click mechanism allows rotary body  37  to stop without failure at a position having a radial angle when rotating. It is apparent from the stop positions of rotary body  37  in FIGS. 5A to  5 C, that the RTE of the embodiment generates an electric signal by making any two out of three elastic contacts  36 A,  36 B,  36 C resilient contact with two conductive layers. 
     In the explanation above, rotary body  37  is rotated in a clockwise direction. In this case, the pattern of the obtained continuity signal follows the order of AI-AII-AIII shown in FIG. 6 in a round-robin fashion. On the other hand, when rotary body  37  is rotated in a counterclockwise direction, the signal shows the pattern following the reversed order, that is, AIII-AII-AI shown in FIG. 6 in a round-robin fashion. 
     On the basis of the generating order of three different electric signals during rotational operation, the control section of the end-use apparatus employing the RTE of the embodiment can detect the amount of change (rotational angle) in rotation and rotating direction. 
     Furthermore, in the RTE of the embodiment, three elastic contacts  36 A,  36 B, and  36 C of movable contact plate  32 , all of which have resilient contact with substrate  31 , are disposed at a same distance from the center of substrate  31 . Such an arrangement allows the diameter of the RTE to be reduced. 
     As shown in FIG. 2, three conductive layers  34 A,  35 B,  35 C having a radial angle of 60° are spaced at 80° intervals on substrate  31 . Therefore, 20° is the angle of the insulation section between conductive layers  34 A and  34 B, and between  34 C. 
     In the state shown in FIG. 5C, for example, elastic contact  36 A contacts with conductive layer  34 A. When rotary body  37  is rotated from the position by 40° in a clockwise direction and reaches the next click position, elastic contact  36 A still remains to contact with layer  34 A. When rotary body  37  is rotated from this position by another 40° then reaches the next click position, elastic contact  36 A now contacts with layer  34 B. Therefore, It is acceptable if the radial angle of conductive layer  34 A is at least greater than 40° and less than 80°. The same goes for conductive layers  34 B and  34 C, that is, it is acceptable if the two layers have the same radial angle with layer  34 A. 
     However, when elastic contacts  36 A,  36 B, and  36 C contact with conductive layers  34 A,  34 B, and  34 C, each contact point of the three contacts has a length that is not negligible. Taking the length into account, the angle in which each of elastic contacts ( 36 A,  36 B,  36 C) is into the OFF state on the insulation section of substrate  31  is decreased by the length contacting with substrate  31 . Furthermore, the length tends to be generally increased with use due to a wearing in rotating. 
     Therefore, given an optimum positional adjustment to conductive layers on substrate  31 , the elastic contacts on movable contact plate  32 , and the click positions, it would be acceptable if each radial angle of conductive layers ( 34 A,  34 B,  34 C) is at least greater than 40° and less than 80°, preferably greater than 45° and less than 75°. 
     In the explanation above, three elastic contacts  36 A,  36 B, and  36 C are disposed such that they contact with the position having a same distance from the center of substrate  31  and resiliently slide on a same circle during rotation. In this arrangement, The contact positions followed by three elastic contacts ( 36 A,  36 B, and  36 C) on substrate  31  may be slightly shifted (approx. 0.1-0.2 mm) in the radial direction. The slight shift of the contact position can minimizes deterioration of three conductive layers  34 A,  34 B,  34 C, and isolation section on substrate  31  due to wearing by sliding, thereby the longevity of the RTE will be improved. 
     Second Preferred Embodiment 
     FIG. 7 is a general perspective view, partially in section, of the rotary encoder with push switch (REPS) functioned as a multi-operational electronic component of the embodiment. In FIG. 7, the REPS is incorporated in an end-use apparatus. FIG. 8 is a cross-sectional front view of the REPS shown in FIG.  7 . FIG. 9 is a sectional view taken along a line  9 — 9  in FIG.  8 . FIG. 10 is an exploded perspective view of the REPS shown in FIG.  7 . 
     The REPS of the embodiment including the RTE and the PS is held by wiring board  42  and holder  41 A that is disposed on upper enclosure  41  of an end-use apparatus. 
     The RTE employed for the REPS of the embodiment has quadrangular frame  43  having side  43 A which functions as a support axle for frame  43 . Holder  4 A, as shown in FIG. 7, rotatably retains side  43 A supporting frame  43 . With the structure, the RTF is rotatably retained between holder  41 A and wiring board  42 . Frame  43  rotatably retains rotary body  45 . Periphery  45 A of rotary body  45 , which functions as the operation section, protrudes from opening  41 C of upper enclosure  41 . In addition, rotary body  45  has movable contact plate  46  having three elastic contacts  46 A,  46 B, and  46 C on its one end. Contact substrate  47  having three fan-shaped conductive layers  47 A,  47 B, and  47 C is formed on side  53  of frame  43  facing to movable contact plate  46 . Plate  46  and substrate  47  are concentrically combined. The RTE employed for the REPS of the present embodiment are structured as described above. 
     Furthermore, self-restoring PS  48  is disposed on wiring board  42 , which lies under side  43 B facing to side  43 A of frame  43 . 
     As described above, the REPS of the embodiment comprises the RTE and PS  48 . With the structure, it makes possible to reduce the diameter of rotary body  45  serving as the operating knob, thereby the enclosure for the apparatus employing the REPS can be reduced in height. 
     Now will be described each element structuring the REPS of the embodiment, referring to FIGS. 7 through 10. 
     Frame  43  comprises: 
     Insulation resin-made U-shaped section  50  including side  43 A functioning as a support axle when rotating, side  43 B facing to section  43 A, and side section  44  connecting sections  43 A and  43 B; 
     Side  53  bridging an open end of U-shaped section  50 ; and 
     Reinforcing hardware  54 . 
     Side  44  has retaining hole  51 A for rotary body  45  and radially undulated portion  52 . Side  53  has retaining hole  51 B for rotary body  45  and contact substrate  47  (see FIG.  8 ). 
     As for forming frame  43 : 
     Boss  55 A at the tip of side  43 A is inserted into hole  53 A of side  53  and hole  54 A of reinforcing hardware  54 , then fixed with thermal caulking. Similarly, boss  55 B at the tip of side section  43 B is inserted into hole  53 B of side  53  and hole  54 B of reinforcing hardware  54 , then fixed with thermal caulking. 
     Furthermore, cylindrical holder  56 A protrudes from one end of side  43 A, while cylindrical holder  56 B protrudes from side  53 . Two holders  56 A and  56 B are disposed on a same axis. Holders  56 A and  56 B are sandwiched between wiring board  42  and U-shaped grooves  41 B respectively formed at each tip of holders  41 A disposed on upper enclosure  41  of the end-use apparatus. With the sandwiched arrangement, as shown in FIGS. 7 and 9, the RTE is retained between upper enclosure  41  of the apparatus and wiring board  42 . The clearance between holder  56 A ( 56 B) and groove  41 B has an enough room for holder  56 A ( 56 B) to rotate, so that holder  56 A ( 56 B) hardly move in a vertical direction. 
     Rotary body  45  is rotatably held by retaining holes  51 A and  51 B that are disposed in frame  43  so as to be faced each other. Periphery  45 A of rotary body  45  functions as the cylindrical operation knob for the REPS of the embodiment. Rotary body  45  holds, as shown in FIGS. 8 and 10, movable contact plate  46  made of flexible thin metal in one recess  45 B, and spring  57  made of flexible thin metal is held in other recess  45 D. Movable contact plate  46  and spring  57  are held so as to be rotatable together with rotary body  45 . 
     Movable contact plate  46  will now be described, referring to FIGS. 10 and 11. FIG. 11 is a side view of the rotary body to which movable contact plate  46  is attached. Movable contact plate  46  is formed in such a way that three flexible legs  46 E, which are identically shaped, are popped-up from circular flat plate  46 D to the positions, having the radial angle of 120° and same distance from the center of circular plate  46 D. Three flexible legs  46 E have elastic contacts  46 A,  46 B, and  46 C on each tip of them. There is a gap between the periphery of circular plate  46  and the inner periphery of recess  45 B of rotary body  45 . Three U-shaped cuts  46 F are disposed close to other base section of each flexible leg  46 E on the periphery of circular plate  46 D. Three projections  45 C disposed on the inner periphery of recess  45 B are press-inserted into the three cuts  46 F. This structure allows movable contact plate  46  to be connected securely with rotary body  45  without deformation or rattling, in spite of a smaller sized periphery of plate  46 D. 
     Although flat plate  46 D is formed in a circular shape in the explanation above, it is also effective to be formed in a regular polygon. 
     Recess  45 B of rotary body  45 , as shown in FIG. 8, faces to contact substrate  47  disposed on side  53  of frame  43 . Three elastic contacts  46 A,  46 B, and  46 C of movable contact plate  46  have a resilient contact with substrate  47 , structuring encoder  58  that generates an electric signal when rotary body  45  rotates. 
     Like contact substrate  31  of the first preferred embodiment, three fan-shaped conductive layers ( 47 A,  47 B,  47 C) made of thin metal plate are disposed on the surface of substrate  47 . The conductive layers are formed from punched thin metal plate, each of which has the radial angle of 60°. And they are formed on substrate  47  by insertion molding, disposed on the positions having a same distance from the center of the substrate, keeping 80° intervals with respect to the center of the substrate. 
     Flexible projection  57 C of spring  57  is, as shown in FIG. 10, formed at the top of flexible arm  57 B that is extended from flat section  57 A. On the opposite side of flexible arm  57 B of flat section  57 A, two tabs  57 D are extended from flat section  57 A. Two tabs  57 D are press-inserted into two holes (not shown) in recess  45 D of rotary body  45 , allowing spring  57  to connect with rotary body without rattling. As shown in FIG. 8, side  44  facing to recess  45 D of rotary body  45  has radially undulated portion  52 , in which the indents are disposed at 40° intervals. Projection  57 C of spring  57  has a resilient contact with one of the indent of radially undulated portion  5 . Such structured encoder  58  produces a click feeling when rotary body  45  is rotated. When rotary body  45  stops, flexible projection  57 C settles into an indent of radially undulated portion  52 . Therefore, movable contact plate  46  retained by rotary body  45  stops at the position corresponding to the indent (click position) of radially undulated portion  52 , which is disposed at 40° intervals. As described above, rotary encoder  58  has a click mechanism that enables to stop the rotation of movable contact plate  46 . 
     On the other hand, three flexible conductors  60 A,  60 B, and  60 C are led out from one end (on side  43 A-side) of side  53  of frame  43 . The conductors  60 A,  60 B, and  60 C have continuity with three fan-shaped conductive layers  47 A,  47 B, and  47 C, respectively. Each tip of conductors  60 A,  60 B, and  60 C is fixed to contact block  61  disposed at lower middle of side  43 A. 
     FIG. 12 is a cross-sectional front view of contact block  61 . Contact block  61  is, as shown in FIG. 12, fixed to wiring board  42 , pressed by flexible body  62  retained by holder  41 A that is disposed on upper enclosure  41  of an end-use apparatus. Flexible conductors  60 A,  60 B, and  60 C have continuity with respective three flexible connectors  62 A,  62 B, and  62 C, which are protruded from contact block  61 . With such a structure, three flexible connectors  62 A,  62 B, and  62 C have continuity with three contact plates  63  on wiring board  42 . In this way, the electric signal generated by RTE  58  can be transmitted to a circuit in the end-use apparatus. 
     As described above, three flexible conductors  60 A,  60 B, and  60 C are led out from positions close to side  43 A that functions as a support axle when frame  43  rotates. Contact block  61  that secures these three conductors is disposed at lower middle of side  43 A. This structure minimizes the amount of deflection of flexible conductors  60 A,  60 B, and  60 C when frame  43  rotates. Besides, the REPS including contact block  61  of the embodiment advantageously has a small mounting area on wiring board  42 . 
     As illustrated in FIGS. 9 and 10, self-restoring PS  48  is disposed on wiring board  42  underlying side  43 B of frame  43 . 
     PS  48  includes fixed contact  48 A, and dome-shaped movable contact  48 B disposed on contact  48 A. Contact  48 A is formed by the conductive layer of wiring board  42 , while contact  48 B is made of flexible thin metal. The top surface of contact  48 B is coated with a flexible insulation film having an adhesive layer on its underneath. Being compact in size, PS  48  is disposed on wiring board  42 , keeping in proper alignment with other structuring components. 
     As illustrated in FIG. 9, pressing projection  48 D formed on the bottom surface of side  43 B of frame  43  contacts with the top surface of self-restoring PS  48 . Pressing projection  48 D is biased upwardly by dome-shaped movable contact  48 B. The upwardly applied force keeps frame  43  so as to stay in the higher position in its rotation range. 
     The REPS of this exemplary embodiment constructed as above operates in a manner, which will be described next. 
     As shown in FIGS. 7 through 9, a portion of periphery  45 A of rotary body  45  is protruded from opening  41  of upper enclosure  41  of an end-use apparatus. The protruded portion of periphery  45 A is functioned as the operating knob. When a force is applied to periphery  45 A in a tangential direction (indicated by the arrow “H” in FIGS.  7  and  9 ), rotary body  45  rotates in the force-applied direction. As rotary body  45  rotates, three elastic contacts  46 A,  46 B, and  46 C, which are disposed on movable contact plate  46  retained at one end of rotary body  45 , resiliently slide on contact substrate  47 . Flexible projection  57 C of spring  57 , which is disposed at the other end of rotary body  45 , resiliently slides on radially undulated portion  52 . RTE  58  operates as described above. 
     As described earlier in the RTE of the first preferred embodiment, referring to FIG. 5, projection  57 C of spring  57  rests in an indentation that is the click position in radially undulated portion  52 . When rotary body  45  is rotated from the state, projection  57 C slides on surface  52  by the distance having angular interval of 40°, then settles into the next indentation, accompanying a click feel. Each time projection  57 C reaches an indentation (i.e. click position), any two out of three elastic contacts disposed on movable contact plate  46  contact with any two out of three fan-shaped conductive layers. Through the movement, as is the case with RTE of the first preferred embodiment described with FIG. 6, the RTE of the embodiment also generates three different electric signals consecutively. The operating of generating signals is the same as that of the RTE of the first preferred embodiment, the detailed explanation will be omitted. 
     The electric signal generated by RTE  58  is transmitted to a circuit in an end-use apparatus via the following elements: 
     1) each of three fan-shaped conductive layers  47 A,  47 B, and  47 C; 
     2) three flexible conductors  60 A,  60 B, and  60 C; 
     3) three flexible connectors  62 A,  62 B, and  62 C; and 
     4) three contact plates  63  disposed on wiring board  42 . 
     As described earlier, side  43 B of frame  43  is biased upwardly by PS  48 . The upwardly applied force is controlled to a magnitude required to keep frame  43  retaining rotary body  45  still while periphery  45 A of rotary body  45  is rotated. 
     The push switch of the REPS operates in a manner, which will be described hereinafter. FIGS. 7 to  9  show the state in which PS  48  presses upwardly, side  43 B of frame  43 , which is retaining rotary body  45 . Against the upwardly pressed force, a depressing force in a vertical direction (indicated by the arrow “VI” in FIGS. 7 and 9) is applied to periphery  45 A of rotary body  45 , which functions as an operation knob. Cylindrical holders  56 A and  56 B disposed on both sides of side  43 A are rotatably retained by U-shaped grooves  41 B of holders  41 A and wiring board  42 . Therefore, the depressing force rotates frame  43  around cylindrical holders  56 A and  56 B. Through this rotation, pressing projection  48 D firmly presses the central part of the top surface of dome-shaped movable contact  48 B in a downward direction through flexible insulation film  48 C. After receiving the depressing force, the central section of movable contact  48 B flips its shape over, accompanying a click feel, so that the depressed central part of contact  48 B contacts with the middle portion of fixed contact  48 E. This brings continuity between fixed switch contact  48 A and the middle portion of fixed contact  48 E, with the result that PS  48  is switched ON. The switching-ON signal is transmitted to a circuit in the apparatus on wiring board  42 . 
     When removed the depressing force applied to periphery  45 A of rotary body  45 , dome-shaped movable contact  48 B of PS  48  restores its original shape by self restoring characteristics, with PS  48  switched OFF again. Following this, side  43 B having pressing projection  48 D is pushed back, so that frame  43  returns to the original position placing top position of the rotation range shown in FIG.  9 . 
     When rotating frame  43  by pressing periphery  45 A of rotary body  45 , a deflection is observed in three flexible conductors  60 A,  60 B, and  60 C. However, as described above, the amount of deflection can be kept to a minimum. 
     Besides, at this time, i.e., while frame  43  is rotating, flexible projection  57 C of spring  57 ,which is retained at one end of rotary body  45 , settles into the indent of radially undulated portion  52  disposed on side  44  of frame  43 . Therefore, rotary body  45  does not rotate with respect to frame  43 , thereby RTE  58  is kept inactive 
     The REPS of the embodiment described above, employs the RTE with small diameter, which detects the amount of change (rotational angle) and rotating direction based on the number of the three different electric signals generated in rotational operation and its generating order. In other words, the REPS of the embodiment employs a cylindrical operation knob with smaller outer diameter and a lower frame in height, with the enclosure of an end-use apparatus kept a low-profile. 
     According to the present invention, as described above, it is possible to detect the amount of change (rotational angle) and rotating direction through the number of the three different electric signals generated in rotational operation and its generating order. Besides, as another advantage, the three elastic contacts, which contact resiliently with a contact substrate, are disposed on the positions having a same distance from the center of the substrate. The arrangement realizes the RTE with a small diameter. Therefore, the RTE contributes to obtain an improved multi-operational electronic component having not only the cylindrical operation knob with a smaller diameter, but also the enclosure of the end-use apparatus with a low profile.