JP5895722B2 - Rotating parts and electronic equipment - Google Patents

Description

  The present invention relates to a rotation operation component attached to a rotation unit for rotating the rotation unit of the rotary electronic component, and an electronic apparatus including these components.

  The rotary electronic component is a component whose setting state varies depending on the rotation angle of the rotating portion provided in the component main body. Specific examples thereof include a variable resistor, a variable capacitor, and a rotary switch. In an electronic device in which this type of component is incorporated, a rotation operation component is attached to the rotation unit, and the rotation unit is rotated by a method of applying a rotational force to the rotation operation component.

FIG. 7 shows an example of a conventional configuration of an electronic device in which the rotary electronic device is 200 and the rotation operation component is 500, and these components 200 and 500 are introduced.
In the figure, reference numeral 300 denotes a case body of an electronic device, in which a circuit board 400 is provided. The rotary electronic device 200 is fixed to a predetermined location on the circuit board 400 and is electrically connected to the circuit pattern on the board 400. A mounting hole 301 for supporting the rotary operation component 500 is formed at a location above the rotary electronic component 200 of the case body 300.

A hole (not shown) is formed in the center of the upper surface of the main body 201 of the rotary electronic device 200, and a rotating part 202 having a recess 203 on the upper surface is fitted into the hole.
The rotation operation component 500 is formed by connecting a shaft portion 503 in series with an operation portion 502 having a screw hole 501, and an attachment piece having a shape corresponding to the concave portion 203 of the rotation portion 202 at the tip of the shaft portion 503. 504 is provided.

  The rotational operation component 500 is operated by inserting the attachment piece 504 and the shaft portion 503 into the case body 300 through the attachment hole 301 and fitting the attachment piece 504 into the recess 203 of the rotation portion 202. The portion 502 is fixed to the rotating portion 202 in a state where the portion 502 is exposed on the surface of the case body 300. A downward stepped portion is formed on the inner peripheral edge of the mounting hole 301, and an O-ring 310 is provided on the stepped portion. The peripheral edge portion of the bottom surface of the operation unit 502 is supported by the upper surface of the case body 300, and the inner portion is supported by the O-ring 310.

  When a driver (not shown) is inserted into the screw hole 501 of the operation unit 502 of the rotary operation component 500 attached by the above method and the driver is rotated, the rotational force is applied from the operation unit 502 to the shaft unit 503. In addition, the rotation part 202 and the rotation operation component 500 rotate together as a result of being transmitted to the rotation part 202 of the rotary electronic device 200 via the attachment piece 504. As described above, the setting for the rotary electronic component 200 inside the case body 300 can be performed by the rotation operation outside the case body 300.

Patent Document 1 below discloses a method similar to that shown in FIG.
Further, in Patent Document 2, in an electronic device in which a rotary electronic component (sensitivity adjustment volume) is incorporated, a support unit for the rotary electronic component is provided inside a lid member connected to the opening of the main body case. It describes that a rotary operation component is attached to a rotary electronic component supported by a support portion, and a circuit board is connected to the support portion to make electrical connection between the rotary electronic component and the substrate.

JP-A-5-67505 JP-A-6-85474

  According to the description of Patent Document 1, it seems that the rotary electronic component on the substrate and the rotary operation component inserted into the main body can be easily connected. There is a possibility that a shift occurs between the rotation axis of the rotary electronic component and the rotation axis of the rotary operation component due to the influence of the shift of the wiring pattern formed on the substrate and the shift of the rotary electronic component with respect to the substrate. Hereinafter, this rotational axis deviation between components is referred to as “axial deviation”.

  If the rotary electronic component and the rotary operation component are connected while ignoring this axial deviation, the connecting portion and the shaft portion are forcibly pulled or pressed to increase the torque. For this reason, even if rotation operation is performed, it may be in the state where a rotation part cannot turn easily. If an unreasonable rotation operation is continued in this state, the rotary electronic component or the rotation operation component may be damaged.

  In order to solve the above-described problem, the invention described in Patent Document 2 positions and fixes the rotary electronic component by the support portion, and then electrically connects to the substrate and connects to the rotation operation component via the support portion. It is carried out. However, if such a method is taken, the number of parts and man-hours increase, resulting in an increase in cost. Moreover, there is a risk of increasing the size of the main body of the electronic device.

FIG. 8 shows an example of a rotary operation component 500A improved for the purpose of solving the above problem.
With respect to the example of FIG. 8, the same configuration as that of the example of FIG. 7 is represented by the same reference numerals as those in FIG. The shaft portion 503 of the rotary operation component 500A in this example is configured by a short shaft portion 505 and a spring portion 506 having a configuration in which a plurality of leaf springs are connected in a rectangular shape. This configuration is based on the idea that even if an axial deviation occurs between the rotary electronic component 200 and the spring part 506 is deformed, the deviation is absorbed. However, the inventors have verified that the rectangular spring portion 506 formed by connecting the leaf springs is deformed in a direction along the diagonal of the rectangle (vertical direction and horizontal direction in the drawing), but penetrates the rectangle. It has been found that the direction (the thickness direction of the leaf spring) does not deform much. Since the axial deviation can occur in an arbitrary direction, it is difficult to sufficiently absorb the axial deviation with the spring portion 506 in which the deformation force varies depending on the orientation.

The present invention has been made by paying attention to the above-mentioned problem, and is capable of absorbing the axial displacement with sufficient deformation force regardless of the direction of the axial displacement with respect to the rotating electronic component. It is a first problem to provide the above.
Furthermore, the present invention has a second object to provide a small electronic device that can easily perform a rotation operation for changing a setting at an affordable price by introducing the rotation operation component. To do.

  A rotating operation component according to the present invention is a component in which a base portion fixed to a rotating portion of a rotating electronic component and an operating portion having a screw hole are connected via a shaft portion, and the rotating shaft is connected to the shaft portion. A spiral spring wound around is included, and the shaft portion, the operation portion, and the base portion are integrally formed of an elastic resin.

  In the rotary operation component having the above-described features, the base portion is fixed to the rotating portion of the electronic component with respect to the main body portion of the electronic device in which the substrate on which the rotary electronic component is mounted is accommodated, and the operation portion is the main body portion. Deployed exposed on the surface. When a rotational force is applied to the operation unit, the entire rotation operation component rotates together with the rotation unit of the rotary electronic component.

The rotary operation component is manufactured entirely from an elastic resin, and the shaft portion includes a spiral spring. Therefore, no matter which direction the axis misalignment with the rotary electronic component occurs, Deformation corresponding to the direction and amount of axial deviation can be caused in the helical spring to absorb the deviation in the shaft portion. Therefore, while preventing excessive force from being applied to the connecting part and shaft part between parts, the operation part is stably supported on the surface of the housing, and the base part is firmly fixed to the rotating part of the rotating electronic part. It becomes possible.
In addition, since the entire component including the spiral spring is integrally formed of an elastic resin, the strength of the entire component can be increased and the manufacturing can be facilitated.

  In one embodiment of the rotational operation component described above, the shaft portion includes a pair of spiral springs whose winding directions are opposite to each other and a connecting portion that is sandwiched between the spiral springs and connects the two. For example, when a right-handed spiral spring is provided on the operation unit side, the other spiral spring connected to the spring via a connecting part is left-handed.

  According to the above configuration, when the base part of the rotating operation component is fixed to the rotating part of the rotating electronic component, the helical spring of the shaft part is slightly contracted to generate a rotational force along the winding direction. In addition, the rotational force of each spring is canceled by the connecting portion, and the rotational force can be prevented from propagating to the rotating portion of the rotary electronic component. Therefore, it is possible to prevent the adjustable range due to the rotation operation from being reduced due to the rotation portion rotating from the initial state.

  In the above embodiment, if the connecting portion is a columnar body having the axial direction of the shaft portion as the length direction, and a pair of spiral springs are formed to have the same length across the connecting portion, the spiral spring and the columnar body Since the configuration of the shaft portion including the is simplified, it is easy to mold the rotary operation component. In addition, since the deformation force of the connecting portion is increased, the responsiveness to the axial deviation is improved.

  According to the rotational operation component of the present invention, the axial displacement can be absorbed in the shaft portion by the deformation of the spiral spring regardless of the direction of the axial displacement with respect to the rotating electronic component. Therefore, the torque with respect to the rotating operation is weakened, the rotating part of the rotating electronic component can be easily rotated, and damage to the component can be prevented.

  In addition, according to the electronic device in which the rotational operation component is introduced, it is possible to reduce the number of components and assembly man-hours and to reduce the size of the device body. Therefore, it is possible to provide a small electronic device that can be easily changed for setting at an affordable price.

It is a perspective view which shows the internal structure of the photoelectric sensor to which this invention was applied. It is the perspective view which looked at the rotational operation component of the basic form from diagonally downward. It is the side view and perspective view of a basic-type rotation operation component. It is the top view which showed the operation part of the basic form rotation operation component with the surrounding case member, the operation part, the support shaft, and the longitudinal cross-sectional view of the surrounding case member. It is the side view and perspective view of a rotary operation component concerning 2nd Example. It is the side view and perspective view of a rotation operation component concerning 3rd Example. It is typical sectional drawing which shows the prior art example of the electronic device in which the rotation type electronic component and the rotation operation component were introduced. It is typical sectional drawing which shows the other conventional example of the electronic device in which the rotation type electronic component and the rotation operation component were introduced.

FIG. 1 shows an internal configuration of a photoelectric sensor which is an example of an electronic apparatus to which the present invention is applied.
The photoelectric sensor of this embodiment is a reflective sensor in which a light projecting unit and a light receiving unit are integrated, and a holder 6 that supports an optical system and a substrate inside a longitudinal case body 2 that is open at the front and rear. It is configured to incorporate. The opening at the front end of the case body 2 is closed by a translucent cover lens (not shown), and the opening at the rear end is closed by a lid (not shown) having a connector.

  The holder 6 is a resin molded product in which a substrate support 62 is integrally provided behind the lens holder 60. The space inside the lens holder 60 is divided into two by a wall portion 61, one being a light guide for light projection and the other being a light guide for light reception. A light projecting or light receiving lens 7 is attached to the front end of each light guide.

  A light shielding plate (not shown) having a light projecting window and a light receiving window is provided at the rear end of the lens holder 60, and a substrate 4 that supports the light projecting element and the light receiving element is mounted behind the light shielding plate. The light projecting element and the light projecting window correspond to a light guide path for light projection, and the light receiving element and the light receiving window correspond to a light guide path for light reception.

  The board support portion 62 extends along the bottom surface of the case body 2, and the circuit board 5 is mounted thereon. On the circuit board 5, a circuit pattern related to the light projecting process and the light receiving process is formed, and the variable resistor 3 is mounted as a rotary electronic component. Although components other than the variable resistor 3 are also mounted on the circuit board 5, they are not shown in FIG.

The variable resistor 3 of this embodiment is a component having a configuration in which a rotating portion 31 is fitted in a hole portion of a cubic main body portion 30 having a hole portion (not shown) in the center. A groove-like recess 32 is formed on the upper surface of the rotating portion 31.
In this embodiment, the variable resistor 3 is electrically connected to a processing circuit for light projection or light reception using a mechanism in which the resistance varies depending on the rotation angle of the rotation unit 31, so The gain can be adjusted manually. For this adjustment operation, the rotation operation component 1 described below is fixed to the rotation unit 31.

The rotary operation component 1 used in this embodiment is a molded product made of a resin having elasticity. FIG. 2 is a perspective view showing a state where the rotary operation component 1 is viewed obliquely from below. 3A shows a state in which the rotary operation component 1 attached to the variable resistor 3 is viewed from one side, and FIG. 3B shows the viewpoint obliquely to the left of FIG. 3A. A state in which the rotary operation component 1 is changed and viewed is shown.
3A and 3B, the direction along one side of the main body 30 of the variable resistor 3 is the width direction, the axis along the width direction is the X axis, and the axis along the depth direction is the Y axis. The axis along the vertical direction is taken as the Z axis. The same applies to the examples of FIGS. 5 and 6 to be described later.

The rotational operation component 1 of this embodiment is a resin molded product having a configuration in which a disc-shaped base portion 11 and a disc-shaped operation portion 12 larger than the base portion 11 are connected via a shaft portion 10.
On the bottom surface of the base portion 11, a protrusion 110 is provided that can be engaged with the recess 32 of the rotating portion 31. A screw hole 120 is formed on the upper surface of the operation unit 12, and a protrusion 121 that is bifurcated through a substantially semicircular cutout 123 is provided at one end of the edge. A downward flange 122 is formed at the tip of the protrusion 121. The screw hole 120 is a plus shape and has a depth reaching the upper end position of the shaft portion 10.

  The shaft portion 10 has a configuration in which a support shaft 101 that is continuous with the operation portion 12 and a short shaft 102 that is continuous with the base portion 11 are connected in series with a helical spring 100 interposed therebetween. The support shaft 101 has a cylindrical body having a diameter slightly larger than that of the base portion 11, which is recessed from the intermediate position to the bottom portion at two locations facing each other on the peripheral surface, and protrudes obliquely upward below each of the recesses 103 and 103. It is the shape which provided the piece 104,104. The short axis 102 is a substantially cylindrical body whose upper end surface is inclined obliquely, and its lower end surface is joined to the central portion of the base 11.

  The spiral spring 100 is integrally formed with other portions by an elastic resin, and is wound approximately twice around the rotation axis of the shaft portion 10 with a wider pitch. Also, the width of the spring is set wide so that the inner side of the winding surrounds the rotating shaft in the vicinity thereof, and the outer side of the winding substantially corresponds to the outer edge portion of the support shaft 101 and the base portion 11. The upper end of the spiral spring 100 is connected to the center of the support shaft 101 via a short connecting shaft 105. Although not clear in FIGS. 2 and 3, the lower end of the spiral spring 100 and the upper end surface of the short shaft 102 are connected in series to form a single surface.

  4 is a top view (FIG. 4A) showing the upper surface of the operation unit 12 of the rotary operation component 1 together with the surrounding case member (a part of the case body), the operation unit 12, the support shaft 101, and the surroundings. The longitudinal cross-sectional view (FIG. 4 (B)) of the range including a case member is shown corresponding to the upper and lower sides.

  A mounting hole 20 penetrating through the thickness portion is formed at a location above the variable resistor 3 of the case body 2 of this embodiment. A downward stepped portion 21 is formed on the inner peripheral edge of the mounting hole 20, and a guide groove 22 is formed on the outer side thereof. The depth of the stepped portion 21 is matched to the thickness of the peripheral edge of the operation portion 12, and the distance from the center portion of the mounting hole 20 to the guide groove 22 is matched to the distance from the center portion of the operation portion 12 to the projection 121. The depth of the groove 22 is adjusted to the length of the flange 122. Further, an inward stepped portion 23 is also provided on the inner bottom portion of the mounting hole 20.

  The step portions 21 and 23 are provided along the entire circumference of the mounting hole 20, but the formation range of the guide groove 22 is limited according to the rotatable range of the rotating portion 31 of the variable resistor 3. On the upper surface of the case body 2, a “+” mark 25 is marked near one end of the guide groove 22, and a “−” mark 26 is marked near the other end. These marks 25 and 26 indicate the direction of adjustment. In addition, linear scale marks 24 along the radial direction of the mounting hole 20 are marked at five locations in the guide groove 22. The notch 123 of the bifurcated projection 121 of the operation unit 121 functions as a display window for the scale mark 24 when the projection 121 is aligned with the scale mark 24.

  2 to 4, the base 11 and the shaft 10 are inserted into the case body 3 through the mounting hole 20, and the protrusion 110 of the base 11 is connected to the variable resistor 3. The pressure is applied until it is fitted in the recess 32 of the rotating part 31. At the time of attachment, an O-ring 8 is attached to the upper end portion of the peripheral surface of the support shaft 101. The protruding pieces 104 and 104 at the bottom of the support shaft 101 are deformed and inserted through the mounting hole 20 at the time of insertion. However, after mounting, the protruding pieces 104 and 104 are positioned below the stepped portion 23 and function as stoppers.

  As shown in FIG. 4 (B), the rotational operation component 1 after the attachment is such that the peripheral edge portion of the bottom surface of the operation portion 12 abuts on the step portion 21 and the inner portion thereof is O. While contacting the ring 8, the flange 122 of the protrusion 121 is engaged with the guide groove 22 and supported. When a rotational force is applied to the operation unit 12, the rod 122 is guided along the guide groove 22. Therefore, the rotation operation component 1 is moved to the rotation unit 31 within a range in which the rod 122 can be moved by the guide groove 22. Can be rotated together.

  The length of the shaft portion 10 of the rotary operation component 1 is set slightly shorter than the distance from the bottom portion of the mounting hole 20 to the rotating portion 31 of the variable resistor 3. Therefore, the helical spring 100 when the attachment of the rotary operation component 1 is completed is in a slightly contracted state. By the urging force of the spiral spring 100 and the O-ring 8 and the engagement of the protrusion 121 with the guide groove 22 of the flange 122, the posture of the operation unit 12 with respect to the case body 3 can be stabilized.

  Since the spiral spring 100 wound nearly two turns with the outer edge aligned with the support shaft 101 and the base 11 has a sufficient deformation force in any direction in the XY plane, Regardless of the direction in which the axial deviation occurs, the spiral spring 100 can be deformed according to the direction and the amount of the axial deviation. In addition, since the upper and lower support shafts 101 and the short shaft 102 of the spiral spring 100 also have elasticity, even if they are pulled or pressed slightly by the deformation of the spiral spring 100, they are deformed according to the force. Can withstand. Therefore, the shaft offset of the variable resistor 3 can be absorbed by the shaft portion 10, and the connecting portion between the rotating portion 31 of the variable resistor 3 and the base portion 12 of the rotary operation component 1 or the shaft portion 10 can be offset. It is possible to prevent the excessive tensile force or pressing force involved. Further, since the winding pitch of the spiral spring 100 is set wide, a deformation force in the height direction (Z-axis direction) is also ensured, and it is possible to cope with variations in distance to the variable resistor 3.

  Therefore, when a screwdriver 120 (not shown) is inserted into the screw hole 120 of the operation portion 12 of the rotational operation component 1 after mounting and a rotational force is applied, the rotational force is transmitted from the operation portion 12 through the shaft portion 10 to the base portion. 11 and the rotation part 31, and the rotation part 31 can be rotated smoothly. Thereby, while making adjustment work easy, damage to the components 1 and 3 can be prevented. Moreover, since it is not necessary to provide another part for preventing an axial deviation, it can be attached in a stable state without increasing costs and man-hours. It is also possible to reduce the size of the sensor.

The rotational operation components 1P and 1Q according to the modified examples are shown in FIGS. 5 and 6 with the rotational operation component 1 shown in FIGS.
5 and 6, similarly to FIG. 3, the side view (A) and the perspective view (B) of the rotary operation components 1 </ b> P and 1 </ b> Q are shown side by side, and the same or corresponding configuration as the basic shape is shown in FIG. 2. -The same code | symbol as shown in FIG. 4 is attached | subjected.

  In the basic rotary operation component 1, in order to stabilize the posture of the operation unit 12, the spiral spring 100 is attached with a pressing force so that the spiral spring 100 contracts slightly. There is a possibility that rotation along the direction occurs, and the rotation propagates to the rotation unit 31 of the variable resistor 3 and the rotation unit 31 rotates. As a result, the rotating portion 31 of the variable resistor 3 is slightly rotated from the initial stage, and the range that can be adjusted by the rotating operation is reduced.

  In view of the above problems, a pair of helical springs 100a and 100b having opposite winding directions are connected in series to the shaft portion 10 of the rotary operation component 1P according to the second embodiment of FIG. 5 via the connecting portion 100c. A spring member of the configuration is included. In the drawing, the upper spiral spring 100a is set to be right-handed, and the lower spiral spring 100b is set to be left-handed. Each of the spiral springs 100a and 100b has a length of about one turn, and the inside of the winding surrounds the rotating shaft of the shaft portion 10 in the vicinity thereof, and the outside of the winding is the outer edge portion of the support shaft 101 or the base portion 12 Corresponding to Further, the spiral springs 100a and 100b are formed in a shape close to line symmetry via the connecting portion 100c.

  The upper and lower end surfaces of the connecting portion 100c are formed as inclined surfaces that are continuously connected to the spiral springs 100a and 100b, respectively. Further, the length of the connecting portion 100c and the connecting position with each spring 100a, 100b are adjusted so that a slight gap is generated between the springs 100a, 100b so that the springs 100a, 100b do not contact each other. Yes.

  In the rotary operation component 1P of the second embodiment, the recess 103 and the protruding piece 104b of the support shaft 101 are provided at a position shifted by about 90 degrees with respect to the basic shape. Further, the direction of the inclination is changed so that the upper surface of the short shaft 102 is also connected to the winding of the left-handed spiral spring 100b.

  According to the above configuration, when the spiral springs 100a and 100b contract due to the pressing force at the time of attachment, the upper spiral spring 100a generates a rotational force in the right direction, whereas the lower spiral spring 100a. A leftward rotational force is generated in the spring 100b. Since the length of each spring 100a, 100b is substantially the same, both rotational force can be canceled in the connection part 100c between both. Thereby, it is possible to prevent the rotation portion 31 of the variable resistor 3 from rotating and to fully utilize the adjustable range.

  In the rotational operation component 1Q of the third embodiment shown in FIG. 6, similarly to the rotational operation component 1P, a pair of spiral springs 100a and 100b whose winding directions are opposite to each other are connected in series via a connection portion 100d. The body is introduced into the shaft 10. The connecting portion 100d of this embodiment is substantially cylindrical, and its length direction is aligned with the axial direction of the shaft portion 10, and the upper and lower end surfaces are inclined so as to be continuous with the spiral springs 100a and 100b, respectively. ing.

  Similar to the second embodiment, the spiral springs 100a and 100b have a length of about one turn, and are set to have a shape that is close to line symmetry via the connecting portion 100d. The support shaft 101 is similar to the basic shape, but the spiral spring 100a and the support shaft 101 are connected via a connection shaft 106 that is slightly thicker than the connection shaft 105 of FIG. The spiral spring 100b and the base 11 are also connected via a connecting shaft 107 having substantially the same shape as the connecting shaft 106.

Also in the rotational operation component 1Q of the third embodiment, the rotational force generated when each of the helical springs 100a and 100b contracts can be canceled by the connecting portion 100d, so that the rotating portion 31 of the variable resistor 3 rotates. This makes it possible to make full use of the adjustable range.
Further, in this rotary operation component 1Q, a sufficient space is ensured between the spiral springs 100a and 100b, and the shape of the connecting portion 100d is simplified, so that molding is facilitated. Further, since the connecting portion 100d is formed into a columnar body, the deformation force of the connecting portion 100d is also increased, so that the connecting portion 100d can be deformed together with the spiral springs 100a and 100b with respect to the axial deviation, and the response to the axial deviation is achieved. Can be increased.

  The basic rotational operation component 1 and the modified rotational operation components 1P and 1Q described above can be applied not only to the variable resistor 3 but also to other rotational electronic components such as a variable capacitor and a rotary switch. . The electronic device into which these components are introduced is not limited to the photoelectric sensor, and the same configuration can be introduced into other types of sensors and electronic devices other than the sensor.

1, 1P, 1Q Rotating operation parts 2 Case body 3 Rotating electronic parts (variable resistors)
5 Circuit board 10 Shaft part 11 Base part 12 Operation part 100, 100a, 100b Spiral spring 100c, 100d Connection part

Claims (4)

A base part fixed to a rotating part of a rotary electronic component and an operation part having a screw hole are connected via a shaft part,
Together include a spiral spring wound around the rotation shaft to the shaft portion, Ri formed is molded integrally with the base portion and the operating portion and the shaft portion is a resin having elasticity,
The shaft portion includes a pair of spiral springs having opposite winding directions and a connecting portion that is sandwiched between the spiral springs and connects the two.
The connecting portion is a rotary operation component including a columnar body that is arranged so that the axial direction of the shaft portion is a length direction and is not eccentric to the rotation shaft at a position eccentric from the rotation shaft . The rotary operation component according to claim 1, wherein each of the pair of spiral springs has a substantially rectangular shape in a cross section orthogonal to an extending direction thereof. A substrate on which a rotating electronic component is mounted is housed inside the main body, and a rotating operation component in which an operating portion having a screw hole and a base are connected via a shaft portion is configured such that the base is the electronic component. In the electronic device that is fixed to the rotating part and is deployed in a state where the operation part is exposed on the surface of the main body part,
The rotary operation component includes a spiral spring wound around the rotation shaft at the shaft portion, and the shaft portion, the operation portion, and the base portion are integrally formed of an elastic resin. The
The shaft portion includes a pair of spiral springs having opposite winding directions and a connecting portion that is sandwiched between the spiral springs and connects the two.
The connecting portion is an electronic device including a columnar body that is arranged so that the axial direction of the shaft portion is a length direction and is not eccentric to the rotating shaft at a position eccentric from the rotating shaft . The electronic device according to claim 3, wherein each of the pair of spiral springs has a substantially rectangular shape in a cross section orthogonal to the extending direction.

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