Electronic component having improved rotary switch detent spring construction

Abstract: This electronic component of the rotary switch type may include: a casing; a disk shaped rotor (34), rotatably supported in the casing, and formed with a cam pattern system; a contact system which is actuated by the cam pattern system (36) as the rotor is rotated; and a sheet spring (10). The sheet spring has: two pressure portions (12a, 12b); a substantially flat portion (F), intermediate between the two pressure portions, which is stressed so as to press the two pressure portions against the cam pattern system as the rotor is rotated, for providing detent action for the rotor; and a fixing portion, fixed to the casing, and proximate and connected to the substantially flat portion. There may be two each of the substantially flat portion and the fixing portion (48). As a specialization, this sheet spring may be generally ring shaped with a generally circular interior outline and a generally square exterior outline, and its two pressure portions may be two of its diagonally opposed corner portions which are creased so as to define projections opposing the cam pattern system, while its two substantially flat portions may be the other two of its diagonally opposed corner portions which are creased so as to press its two pressure portions against the cam pattern system. Also, this electronic component may include a resin casing with a terminal passing through it and a hole formed through it from its surface to the terminal, with some thermosetting bonding agent filled into the hole and sealing the terminal to the casing.

Description: The present invention relates to an electronic component, and particularly to an electronic component which is a rotary switch which has an improved type of detent spring construction, so that the detent action for said rotary switch can be stronger and more positive than heretofore practicable. In the prior art, there have been proposed various types of rotary switch type electronic components, such as so called rotary DIP switches. Such rotary switch type electronic components have typically included a disk shaped rotor member which can be rotated from the outside to actuate the rotary switching action. Typically, in such a construction, when this disk shaped rotor member is rotated, irregularities formed on its surface (either on one of its end surfaces or on its circumferential surface) drive various movable contacts to and fro, so as to make or to break various electrical or electronic circuits. Also, typically, a detent action has been provided for such rotary switching action; i.e., a detent mechanism has been provided for giving a stepwise clicking feeling to the turning action of the disk shaped rotor member, and for preferentially indexing said turning action of said rotor member to particular rotary positions. A rotary switch type electronic component according to the preamble of claim 1 (with the fixing portions fixed to terminals instead of to the casing) is known from US-A- 4 000 597. The sheet spring of the known switch is in the shape of a spider, the fixing portions of the sheet spring being formed by two opposed spider legs. The pressure portions are formed by other two spider legs alternating with the fixing portion spider legs. There has become evident a requirement for an improved electronic component. This problem has exercised the ingenuity of the inventors of the present invention. The invention is defined in claim 1. The present invention will now be described with respect to the preferred embodiments thereof, and with reference to the illustrative drawings appended hereto, which however are provided for the purposes of explanation and exemplification only, and are not intended to be limitative of the scope of the present invention in any way, since this scope is to be delimited solely by the accompanying claims. With relation to the figures, spatial terms are to be understood as referring only to the orientation on the drawing paper of the illustrations of the relevant elements, unless otherwise specified; like reference symbols, unless otherwise so specified, denote the same parts and spaces and so on in the various figures relating to one preferred embodiment, and like parts and spaces and so on in figures relating to different preferred embodiments; and: Fig. 1 is an exploded perspective view showing the principal portions of the first preferred embodiment of the rotary switch type electronic component of the present invention; Fig. 2 is a plan view relating to said first preferred embodiment of the rotary switch type electronic component of the present invention, showing a portion of the casing of said first preferred embodiment rotary switch housing a sheet spring of a novel type for providing a detent action for this first preferred embodiment rotary switch, said sheet spring being in this first preferred embodiment fixed to the casing by thermal crimping; Fig. 3 is a plan view, similar to Fig. 2 which related to the first preferred embodiment of the present invention, but relating to the second preferred embodiment of the rotary switch type electronic component of the present invention, again showing a portion of the casing of said second preferred embodiment rotary switch housing such a detent action sheet spring, said sheet spring being in this second preferred embodiment fixed to the casing by press fitting; and Fig. 4 is a plan view, similar to Figs. 2 and 3 which respectively related to the first and the second preferred embodiments of the present invention, but relating to the third preferred embodiment of the rotary switch type electronic component of the present invention, again showing a portion of the casing of said third preferred embodiment rotary switch housing such a detent action sheet spring, said sheet spring being in this third preferred embodiment fixed to the casing by snap fitting; The present invention will now be described with reference to the preferred embodiments thereof, and with reference to the figures. The First Preferred Embodiment Fig. 1 is an exploded perspective view showing the principal portions of the first preferred embodiment of the rotary switch type electronic component of the present invention. In this figure, the reference numeral 14 denotes a cover member for this rotary switch, and the reference numeral 18 denotes a base member thereof. The switch cover member 14 is fitted securely to the switch base member 18, when the switch is assembled, with the other parts of the switch enclosed and held between them. There are provided a plurality of terminal members 20 which are embedded in and pass through the material of the switch base member 18, as will be more particularly described later, and exterior portions of which are projected to the outside of the rotary switch and are bent over, so as to be connected to a printed circuit board to which this rotary switch is to be fitted. Inner end portions, not particularly shown in this Fig. 1 of this plurality of terminal members 20 are connected to or, in this particular case, constitute a plurality of fixed contact members 22, which are exposed on the inner surface of the switch base member 18 at appropriate positions, as will be described hereinafter; these positions, in this particular preferred embodiment of the present invention, are arranged along a line. Further, there are formed from the material of the switch base member 18 as protruding upwards in the figure from its inner surface two fixing pins 24, and further at a generally central position on said inner surface of said switch base member 18 there is formed a circular depression or socket 32 which is for serving as a bearing hole. A contact plate 26 is formed in the general configuration of a comb, and the projections 30 thereof (there are in all four such projections 30, in the shown exemplary embodiment) are crinkled to and fro, so as to define upwardly projecting intermediate drive bumps 38 at their intermediate portions and movable contact portions 40 at their free ends which are bent round into upwardly opening letter "U" shapes. Further, two fixing apertures 28 are formed in said contact plate 26. During assembly of this rotary switch, the contact plate 26 is placed over the switch base member 18 with the fixing pins 24 of said switch base member 18 fitting into the fixing apertures 28 of said contact plate 26, and then the ends of the fixing pins 24 are crimped as for example by thermal crimping, so that the contact plate 26 is securely fitted in place over the switch base member 18. In this state, each of the movable contact portions 40 opposes an appropriate one of the fixed contact members 22, being, in the unstressed state of the contact plate 26 and of the projections 30, separated from said one of said fixed contact members 22 by a certain gap. The reference numeral 34 denotes a disk shaped rotor member which is rotatably supported between the switch cover member 14 and the switch base member 18. The lower surface of this rotor member 34 from the point of view of Fig. 1 is formed on its radially outer circumferential portion - only slightly visible in the Fig. 1 view - with a wary irregular pattern denoted as 36 but not clearly or completely shown in the figures. Further, at the center of this lower surface of this rotor member 34 from the point of view of Fig. 1 there is provided a stub shaft, not shown in the figures. On the other hand, the upper surface of this rotor member 34 from the point of view of Fig. 1 is formed on its radially outer circumferential portion with a wavy irregular pattern denoted as 44, which is used for providing detent action as will be explained hereinafter, while its central portion is formed as a raised disk portion denoted as 8, in the center of the upper surface of which a slot 42 suitable for receiving the tip of a screwdriver is formed. When this rotary switch is assembled, the downwardly extending (from the point of view of Fig. 1) stub shaft thereof is rotatably fitted into the bearing hole socket 32 formed as described above on the inner surface of the switch base member 18, and then as the switch cover member 14 is fitted over said switch base member 18 the raised disk portion 8 of said rotor member 34 is rotatably fitted into a correspondingly shaped and sized circular aperture 46 formed in said switch cover member 14, with the interposition of a sealing O ring denoted as 45; thereby, the rotor member 34 is rotatably supported within the body of the rotary switch, and can conveniently be turned about its central axis by a user fitting the tip of a screwdriver into the slot 42 and turning said screwdriver. When this is done, as the rotor member 34 is rotated about its rotational axis, at each of various preferred positions thereof which are defined as will be explained hereinafter, the wary irregular pattern 36 formed on the lower surface of said rotor member 34 from the point of view of Fig. 1 pushes as appropriately arranged on appropriate ones of the intermediate drive bumps 38 of the projections 30 of the contact plate 26 and does not push on other appropriate ones of said intermediate drive bumps 38, thereby pushing down appropriate ones of the movable contact portions 40 at the ends of said projections 30 so as to contact with the corresponding ones of the fixed contact members 22 but not pushing down other appropriate ones of said movable contact portions 40 to contact with their corresponding ones of said fixed contact members 22; and thereby appropriate electrical connections are made between the various terminal members 20 of this rotary switch, according to the particular rotational position thus imparted by the user to the rotor member 34 - in other words, a digital signal is made available at said terminal members 20. This type of rotary switch can be used, for example, as a rotary DIP switch, or for some other application. Now the detent mechanism which is provided for the rotatory action of the rotor member 34 will be explained. This detent mechanism comprises a sheet spring member 10 which is sandwiched between the upper face from the point of view of Fig. 1 of the rotor member 34 and the lower surface of the switch cover member 14. This sheet spring member 10 is shown in perspective view in Fig. 1, while being shown in plan view in Fig. 2, from the point of view of which figure it lies in front of the radially outer circumferential portion of the rotor member 34 and hides the wary irregularities 44 formed on the outer circumferential portion of said rotor member 34. This sheet spring member 10 is formed with an approximately square external outline, except that, from each of two substantially flat portions denoted as "F" each of which includes one of a diagonally opposing pair of corners of said square external outline, there extends a mounting ear portion denoted as 48, connected to the main body of the sheet spring member 10 by a narrow connecting bridge portion denoted as 51, on the one side of which there is defined a notch shape 50. Each of these mounting ear portions 48 is formed with a circular opening 52. Further, the sheet spring member 10 is formed with an approximately circular internal outline which is substantially concentric with its general square external outline, and which fits over the raised disk portion 8 of the rotor member 34. Further, the three dimensional shape of this sheet spring member 10, not particularly shown in Fig. 2 but generally visible in Fig. 1, is as follows: the diagonally opposed pair of portions "F" thereof including one diagonally opposed pair of corners of the sheet spring member 10 are substantially flat and are not distorted substantially out of the plane of the drawing paper of Fig. 2, except that each of them is formed with two very slight creases denoted as 15a1 and 15a2, and 15b1 and 15b2, which serve for slightly angling the two portions which constitute the major portion of the remainder of the sheet spring member 10 as a whole in the direction towards the viewer from the point of view of Fig. 2; while each of the other diagonally opposed pair of portions, denoted as 12a and 12b and including the other diagonally opposed pair of corners of the sheet spring member 10, is formed with three obtusely angled creases denoted as 13a1, 13a2, and 13a3 for the portion 12a and as 13b1, 13b2, and 13b3 for the portion 12b. The obtuse angles of the creases 13a1 and 13b1 face away from the viewer from the point of view of Fig. 2, while on the other hand the obtuse angles of the creases 13a2, 13a3, 13b2, and 13b3 face towards the viewer from the point of view of Fig. 4. Thereby, each of these diagonally opposed portions 12a and 12b of the sheet spring member 10 is formed in a shallow V shape, with the apexes or points of these V shapes being constituted by the obtusely angled creases 13a1 and 13b1 and each being displaced in the direction forward from the drawing paper with respect to the remainder of its portion 12a or 12b from the point of view of Fig. 2 and in the direction pointing downwards from the point of view of Fig. 1. Now, through the openings 52 formed in the mounting ear portions 48 there are passed fixing pins 16a and 16b formed as projecting towards the viewer from the point of view of Fig. 2 on the lower surface as seen in Fig. 1 of the switch casing 14, and these fixing pins 16a and 16b are, in this first preferred embodiment of the present invention, thermally crimped over so as to securely and fixedly attach these mounting ear portions 48 and thereby the sheet spring member 10 as a whole to this surface of the switch casing 14. In this position, when the rotary switch is assembled as described earlier, the apexes 13a1 and 13b1 of the V shapes formed in the diagonally opposed portions 12a and 12b of the sheet spring member 10 are forcibly pressed against the radially extreme circumferential portion of the upper surface as seen in Fig. 3 of the rotor member 34 and against the wavy irregularities 44 formed thereon, with some distortion of these portions 12a and 12b of the sheet spring member 10 in the direction away from the viewer from the point of view of Fig. 2, and of said sheet spring member 10 as a whole, being forced at this time. Thus, as the rotor member 34 is turned, by the indexing action of these wary irregularities 44 thereof against these apexes 13a1 and 13b1 of the V shapes of the diagonally opposed portions 12a and 12b of the sheet spring member 10, a stepwise clicking or detent action is provided for this rotary motion, with said apexes 13a1 and 13b1 clicking into the depressed portions of these wavy irregularities by the spring action of the sheet spring member 10 and thus defining preferential rotational positions for the rotor member 34, into which said rotor member 34 tends to be retained during its rotational action; and, provided that the dimensions of the various members are appropriate, these preferential positions of the rotor member 34 will be the ones described above, at which said rotor member 34 performs its various required switching actions for the movable contacts 30 against the fixed contact members 22. According to this construction according to the first preferred embodiment of the rotary switch type electronic component of the present invention, because the substantially flat diagonally opposed portions "F" of the sheet spring member 10 which are intermediate between the V shape apexes 13a1 and 13b1 of the diagonally opposed portions sheet spring portions 12a and 12b are not pierced with any apertures such as the openings 52 but instead are continuous - which is accomplished by performing the mounting of said sheet spring member 10 by fixing the mounting ear portions 48, which are separate portions from said portions "F", to the material of the switch cover member 14 - thereby accordingly the stress set up in the sheet spring member 10 by the above explained distortion of said sheet spring member 10 in the direction away from the viewer from the point of view of Fig. 1, which as explained above tends to be concentrated in said substantially flat diagonally opposed portions "F" of the sheet spring member 10, can much better be distributed. Accordingly it will be easily understood that, with the other constructional parameters of the rotary switch remaining the same, since relative to the prior art the area of these substantially flat diagonally opposed portions "F" is effectively much increased, the maximum level of the stress in said substantially flat diagonally opposed portions "F" is decreased. In other words, for a determinate maximum possible level of stress in said substantially flat diagonally opposed portions "F", as before this maximum possible stress level being fixedly determined according to the material and the thickness of the sheet spring member 10, a much greater usable spring action is available from the sheet spring member 10, since the effective area of the substantially flat diagonally opposed portions "F" is much greater and further is more effectively and efficiently utilized (since no holes are pierced through said diagonally opposed portions "F" and further no portions of said diagonally opposed portions "F" are fixed to the switch cover member 14), and accordingly the greater is the detent action available from this rotary switch as a whole. Accordingly it is possible to maximize the effectiveness of this detent action, thus preventing any likelihood of improper action or of improper contact setting function of this rotary switch; and this has been done without it being required to construct the sheet spring member 10 and the rotary switch as a whole particularly more robustly than heretofore. Accordingly this construction according to this first preferred embodiment of the rotary switch type electronic component of the present invention does not entail any particularly severe cost or weight or bulk penalties. A further benefit of the shown first preferred embodiment construction is attained by the provision of the notches 50 which are present between the mounting ear portions 48 and the diagonally opposed portions "F" of the sheet spring member 10, because this further isolates the stress bearing function of said diagonally opposed portions "F" from the function of said mounting ear portions 48 of fixing the sheet spring member 10 to the switch cover member 14, thereby further allowing less concentrated and more uniform and therefore overall greater stress bearing action to be provided by said diagonally opposed portions "F". The Second Preferred Embodiment Next, with regard to Fig. 3, the second preferred embodiment of the electronic component of the present, invention will be described. It should be understood that, in Fig. 3, like reference symbols to reference symbols in previous figures relating to the first preferred embodiment correspond to like elements. This second preferred embodiment differs from the first preferred embodiment described above, only in that the sheet spring member 10 is attached by the fixing pins 16a and 16b to the switch cover member 14, not by the use of thermal crimping as was the case in said first preferred embodiment, but by press fitting of said fixing pins 16a and 16b into the openings 52 of the mounting ear portions 48. Otherwise the construction is the same as in the first preferred embodiment, and accordingly the same advantages and benefits accrue as in this case of said first preferred embodiment. The Third Preferred Embodiment Next, with regard to Fig. 4, the third preferred embodiment of the electronic component of the present invention will be described. It should be understood that, in Fig. 4, like reference symbols to reference symbols in previous figures relating to the first and the second preferred embodiments correspond to like elements. This third preferred embodiment differs from the first and the second preferred embodiments described above, only in that the sheet spring member 10 is attached by the fixing pins 16a and 16b to the switch cover member 14, not by the use of thermal crimping as was the case in said first preferred embodiment or by press fitting as was the case in said second preferred embodiment, but by snap fitting of the fixing pins 16a and 16b into the openings 52 of the mounting ear portions 48. Otherwise the construction is the same as in the first and the second preferred embodiments, and accordingly the same advantages and benefits accrue as in this case of said first and second preferred embodiments.

Claims: A rotary switch type electronic component, comprising: a casing (14, 18), a disk shaped rotor member (34), rotatably supported in said casing, and formed with a cam pattern system, a contact system (22, 26) which is actuated by said cam pattern system formed on said disk shaped rotor member as said disk shaped rotor member is rotated, and a sheet spring (10) comprising two pressure portions (12a, 12b), two substantially flat portions (F, F) each intermediate between said two pressure portions, which are stressed so as to press said two pressure portions against said cam pattern system formed on said disk shaped rotor member as said disk shaped rotor member is rotated, for providing detent action for said disk shaped rotor member, and two fixing portions (48, 48), each fixed to said casing, and each proximate and connected to a corresponding one of said substantially flat portions, characterized in that said sheet spring (10) is generally ring shaped with a generally circular interior outline and a generally square exterior outline, and said two pressure portions thereof are constituted by a pair of two diagonally opposed corner portions (12a, 12b) thereof which are creased so as to define projections opposing said cam pattern system formed on said disk shaped rotor member (34), while said two substantially flat portions (F, F) thereof are constituted by the other pair of two diagonally opposed corner portions thereof which are creased so as to press said two pressure portions thereof against said cam pattern system formed on said disk shaped rotor member (34). An electronic component according to claim 1, wherein said fixing portions (48, 48) of said sheet spring (10) are connected to said substantially flat portions (F, F) thereof by narrowed portions (51, 51). An electronic component according to claim 2, wherein notches (50, 50) are defined on the one sides of said narrowed portions (51, 51) of said sheet spring (10) between said fixing portions thereof and said substantially flat portions (F, F) thereof. An electronic component according to anyone of the preceding claims, wherein each of said fixing portions (48, 48) is formed with an aperture (52, 52) by which it is fixed to said casing (18). An electronic component according to anyone of the preceding claims, wherein said fixing portions (48, 48) are fixed to said casing (18) by thermal crimping. An electronic component according to anyone of the claims 1 - 4, wherein said fixing portions (48, 48) are fixed to said casing (18) by press fitting. An electronic component according to anyone of the claims 1 - 4, wherein said fixing portions (48, 48) are fixed to said casing (18) by snap fitting.

Inventors: IWAKIRI NORIO OMRON TATEISI EL, YAMANAKA SEKISUKE OMRON TATEIS, YAMASHITA MASATSUGU OMRON TATE, YANASE AKIRA OMRON TATEISI ELE, IWAKIRI, NORIO OMRON TATEISI ELECTRONICS CO., YAMANAKA, SEKISUKE OMRON TATEISI ELECTRONICS CO., YAMASHITA, MASATSUGU OMRON TATEISI ELECTRONICS CO., YANASE, AKIRA OMRON TATEISI ELECTRONICS CO.
Applicants: OMRON TATEISI ELECTRONICS CO, OMRON TATEISI ELECTRONICS CO.
Application year: 1987
Main classification: H01H19
IPC codes: H01H1