US 3694602 A
A pushbutton controlled rotary switch in which springs move into corners of an appropriately shaped opening in order to hold the switch in its various operative positions.
Claims available in
Description (OCR text may contain errors)
[451 Sept. 26, 1972 Unitefi States Patent Iwasaki  ROTARY SWITCE-I HAVING A  References Cited UNITED STATES PATENTS TORSION SPRING SNAP MECHANISM  Inventor:
1/1968 Krehbiel ..................200/67 C 3,291,929 12/1966 Wanlass...................200/67 C 3,355,565 Daul ....................200/166 SD 3,015,706 Fichter.....................200/67 C Sadayoshi lwasaki, Tokyo, Japan 3,366,755  Asslgnee: Alps Electric Co., Ltd., Tokyo,
Japan I 11/1967 22 Filed: 1/1962 Nov. 19, 1970 Primary Examiner1-l. 0. Jones  Appl. No.: 91,150
Attorney-James & Franklin Related US. Application Data  Division of Ser. No. 869,717, Oct. 27, 1969,
Pat. No. 3,624,582.
springs move into corners of an appropriately shaped (ghmwzomlss L200/67 opening in order to hold the switch in its various 0 .QI-iUh.Q'Ulhllin.Ill-l'IlIli- UUIIIIQIIIII. t 't-  Field of Search..... ......2o0/153 L, 67 c, 166 so pera we ms 6 Claims, 19 Drawing Figures PATENTEDszrzs I972 sum 1 or s KIIII I-IIII IA'IIIIIIIIIIIIIII M ll/1111 PATENTED SEP 2 6 I972 SHEET 3 OF 5 PATENTEDsms I972 sum u 0F 5 ROTARY SWITCH HAVING A TORSION SPRING SNAP MECHANISM This application is a division of my application Ser. No. 869,717, filed Oct. 27, 1969, US. Pat. No. 3,624,582 entitled Control Device Employed for Tuner or the Like and assigned to the assignee of this application. This invention generally relates to control devices, and more particularly to such devices which include variable resistors or voltage dividers and are employed for a tuning circuit utilizing a capacitive diode (varactor diode) or the like.
The capacitive diode is a kind of semiconductor element wherein the thickness of the scarcity layer is varied in accordance with the magnitude of the voltage applied thereto, whereby the capacitance is correspondingly varied.
When this kind of diode is employed as a static variable capacitor, various kinds of tuning circuits may be constituted.
As is apparent from the above, when it is desired to use the capacitive diode as a variable capacitor, a control device such as a voltage divider for controlling the voltage applied to the diode, is required.
Furthermore, it is also required that an indicator be provided for the control device in order to indicate the tuning condition of the circuit. This invention is directed to an improvedconstruction of such a control device including an indicator.
' A control device of this general kind is shown in French Pat. No. 1,462,305. That control device comprises a series of variable resistors provided in correspondence to a series of channels, all of the variable resistors being formed in one unit module. A plurality of operating shafts are provided the number of which corresponds to the number of the channels. The variable resistors having sliding contact members, and there is mechanism for converting the movement of the operating shafts into sliding motion of the contact members, whereby the individual variable resistors are adjusted by means of their respective operating shafts to vary their output voltages.
However,the control device described in the French patent has shortcomings, and it is the primary object of the invention to provide an improved construction of the control device whereby all of those shortcomings are substantially eliminated.
Another object of the present invention is to provide a control device wherein an indicator plate is freely detachably mounted on the base plate so that the control device may also be employed as a thinner type device. I
'Still another object of the invention is to provide an improved control device wherein a connector may be employed. for connecting the lead wires of the control device to an outside circuit.
Still another object of the invention is to provide a novel construction of an AFC switch.
Still another object of the invention is to provide a control device including an AFC switch and the above described voltage dividers in one casing.
These and other objects of the invention can be attained by an improved construction of the control device including a plurality of variable resistors the number of which corresponds to the number of the channels, said variable resistors being formed into a single module, a number of operating shafts also corresponding to the number of channels, sliding contact members for the variable resistors, and mechanisms for converting the rotation of said operating shafts to sliding movement of said sliding contact members, andwhereby a voltage applied to the outside circuit is controlled by the sliding movement of the sliding contact member which is driven by the rotation of the operating shaft; the improvement comprising two lead wires connected to the ends of the variable resistors and one central tap lead wire connected to said sliding contact member, when it is required, by means of a switching mechanism, all of said lead wires being formed in a single module.
Another feature of the present invention is that the ends of said two lead wires andone center tap lead wire, all formed in a single module, are arranged on one side of an insulating plate so that the ends of the lead wires are reliably spaced from one another by equal distances.
Still another feature of the present invention is that the rotating movement of the operating shaft is converted into the sliding movement of the sliding contact member by mechanism including a guiding portion directly coupled toeach of the operating shafts, said guiding portion extending above and parallel to the variable resistors and so constructed that when a contact member slides along a corresponding guiding portion of an operating shaft, the contact member slides along one of the variable resistors in a reliable contacting relationship thereto.
Still another feature of the present invention is that there are provided, on the ends of the operating shafts opposite to said ends coupled to the guiding portions for the sliding contact members, a plurality of sleeveshaped knobs normally rotationally disengaged from their respective operating shafts and axially movable for a predetermined length along said shafts, the knobs being so constructed that when they are pushed rearwardly for the predetermined length along the shafts, they rotationally engage with the operatingshafts, after which the knobs and the operating shafts may be rotated in unison.
Still anotherv feature of the invention is that on the rear side of the knobs there are drum members which are fixed to the knobs, slide along the operating shafts, and have conical surfaces. A locking plate is arranged in such a manner that the tip of the front edge thereof is urged against the conical surfaces of said drums, said knobs and drums being pushed back toward the forward ends thereof by means of retracting springs provided respectively on said operating shafts. In the normal condition the knobs and drums are retracted to the forward positions on the operating shafts and are thus retained in the non-operable condition. When a knob is pushed rearwardly, the forward end of said drum member coupled to said knob is engaged and locked by said locking plate, whereby the knobs and drum are maintained in the rearward position where they can be rotated in unison with the operating shaft.
Still another feature of the present invention is that at the rear side of each drum member a movable plate is arranged on the operating shaft to be reciprocable along the operating shaft together with each said knob and drum. Two mutually connected contacts are provided on said movable plate, the contacts being slidable n the fixed contacts.
on the insulating plate when the movable plate is reciprocated along the operating shaft. A plurality of fixed contacts are provided on said insulating plate, a pair of the fixed contacts being connected together by said two movable contacts when a knob is maintained in the rearward position, one of the pair of fixed contacts being electrically connected to said central tap lead wire, the other of the pair of the fixed contacts being electrically connected to the appropriate one of the operating shafts. Hence a switching mechanism is formed by the movable contacts and said one pair of Still another feature of the invention is that in the above described voltage control device, comprising an insulating plate on which are located said moduleformed resistors, lead wires, a central tap lead wire, and said fixed contacts, a plurality of operating shafts are provided, each coupled to a guiding portion for a sliding member and extending above said insulating plate, said operating shaft having a knob and a drum at the forward end thereof, a locking plate for locking such drums on said plurality of operating shafts, and a movable plate having interconnected contacts mounted slidably on each of the operating shafts. In addition a plurality of windows are formed in the cover of the control device, each of said sliding contact members having a projection at an end opposite to that which slides along the corresponding resistor, and said projection is so arranged that it may be exposed in one of said windows provided in said element cover, thus constituting an indicator which displays the adjusted conditions of the control device by the exposed conditions of the projections.
Still another feature of the present invention is that the indicator plate is freely detachably mounted on the housing at a position near the front end portion thereof, 'a plurality of windows being formed in that plate as described above, said indicator plate being oriented to make a desired anglewith the axial direction of the operating shafts. Grooves are formed on both sides of each window in the plate and a flexible ribbon is guided by said grooves, one end of each ribbon being fixed to a corresponding sliding member, whereby the controlled positions of the sliding contact members along the variable resistors may be read from the positions of the other ends of the ribbons in said windows in the indicator plate.
An additional feature of the present invention is that one of the operating shafts is provided with a rotary switch including a cam plate rotated by said operating shaft and operable to open or close the contacts instantaneously with the aid of a reversible spring.
The above described objects, features, and means for achieving these objects and features of the present invention will be made apparent from the following description with respect .to preferred embodiments thereof when read together with the accompanying drawings, wherein:
FIG. 1 is a sectional view showing a construction of a control device constituting one embodiment of the present invention;
, FIG. 2 is a perspective view, partially broken away, of one part of the control device shown in FIG. 1 illustrating the portion in more detail;
FIGS. 2A and 2B are enlarged detail cross sectional views showing the pushbutton-operating shaft connections, FIG. 2A showing the pushbutton in a disconnected position relative to the shaft and FIG. 2B showing the pushbutton in a connected position relative to the shaft;
FIG. 3 is another perspective view, much enlarged, showing the relation between the resistors and the sliding contact members in the control device shown in FIG. 1;
FIG. 4 is still another perspective view illustrating the switching mechanism in the control device shown in FIG. 1;
FIG. 5 is an outside perspective view of the device shown in FIG. 1;
FIG. 6 is a sectional view, partly broken away, indicating the construction of the indicator portion in the control deviceshown in Fig. 1;
FIG. 7 is an enlarged perspective view indicating in more detail the construction of the indicator portion of the device shown in FIG. 1; V
FIG. 7A is a cross sectional view of the sliding member, taken along the line 7A-7A of FIG. 7;
FIG. 8 is a sectional view showing one part of another example of the control device of this invention which has an indicator plate inclined at a desired angle to the vertical; I
FIGS. 9A, 9B and 9C are fragmentary perspective views showing applications of the control device of the present invention to receivers;
FIG. 10 is a perspective view of an AFC switch also constituting one part of the present invention;
FIG. 1 1 is an exploded view of the AFC rotary switch shown in FIG. 10 indicating the construction in more detail; and
FIGS. 12A, 12B and 12C are views explaining the operation of the rotary switch-shown in FIG. 10.
Referring now to FIG. 5 showing an outside view of a control device constituting an embodiment of -the present invention, reference numeral 1 designates an element cover and reference numeral 2 designates a front frame, both constituting a casing for the control device. Numeral 3 designates an indicator plate, numeral 4 designates a plurality of knobs arranged to be projecting from the front plate 5 of the casing, the number of the knobs corresponding to the number of channels to be turned, and numeral 6 designates a knob for an AFC switch. On the indicator plate 3, a plurality of vertically extending windows 7, one for each channel to be tuned, are provided. On the horizontal surface of the element cover 1, a plurality of windows 8 are provided. Numeral 9 designates flexible ribbons, one end of each of the ribbons being fixed to'a sliding member exposed through each of thewindows 8, each ribbon extending to one of the windows 7 on the indicator plate 3.
Referring to FIG. 1 through FIG. 5 indicating internal construction of the control device according to the present invention, there is provided a printed circuit board on plate 10, on which are further provided resistors 11, one for each channel to be turned (only one of them is shown), printed paths 12a and 12b, made of for instance copper and acting as lead wires connected to both ends of the resistors 11, another printed path employed as another lead wire for a central tap connected to a sliding member (hereinafter described) I slidable along each of the resistors 11, a plurality of fixed contacts 13a connected to the printed path 120, anda plurality of fixed contacts 13b to be connected to the fixed contacts 132 and to be electrically connected to the sliding members through the operating shafts (also described hereinafter). These fixed contacts 13aand 13bare provided in a number of pairs corresponding to the number of the channels (in the drawings, only two pairs are indicated).
The printed circuit board or plate is placed between the front plate. 5 of the frame 2 and the rear wall 5a thereof so that the plate 10 also forms a bottom plate for the casing. Therefore, the surface of the plate 10 on which the above described resistors 11 and the paths 12a, 12b and 12c are provided is the upper surface thereof and the plate 10 is arranged so that all of the resistors 11 extend between the front plate 5 and the rear wall 5a.
Numeral l4 designates the operating shafts which also extend between the front plate 5 and the rear wall 5a (passing freely through intermediate wall 5b) and are rotatable about their axes. The number of shafts 14 corresponds to the number of channels to be tuned. About one half of the length of the operating shafts 14 is formed with screw threads 14' defining guiding portions for the sliding members are thereby provided, those guiding portions 14 extending above, along and parallel to the resistors 11. The sliding member 15 has a contact point engaging and sliding along a corresponding resistor 11 when the operating shaft 14 is rotated around its axis. The construction of the sliding member 15, and its manner of attachment to the screw threaded portion 14 of the shaft 14 is best shown in FIGS. 7 and 7A. The sliding member 15 comprises a housing 130 provided with a longitudinally extending passage 131 extending therethrough and with slots 133 formed in the lower surface 135 of the housing 130 and communicating with the passage 13]. The conductive contact strip 137 is arcuately bent and has end portions 139 which are adapted to pass through the slots 133 into the passage 131, those end portions having arcuate recesses 141 formed therein. The shaft 14, and in particular the screw threaded portions 14' thereof, is adapted to extend through the passage 131, the arcuate recesses 141 in the contact strip 137 being pressed up against the shaft 14 so as to engage with the screw threaded portion 14' thereof, the contact strip 137 thus being compressed between the shaft 14 and the corresponding resistor 11 on the circuit board 10. Hence as the shafts 14 are rotated the corresponding slidable members 15 will be moved axially therealong. This is, of course, but one way in which the appropriate mounting of and operative connection to the sliding members 15 may be achieved.
On the ends of the operating shafts 14 projecting forwardly from the front plate 5 are attached the above described knobs 4 which are freely shiftable along the longitudinal direction of the shafts 14. When the knobs 4 are pushed to the utmost rearward position along the operating shafts 14 (to the right as viewed in FIG. 1), the knobs 4 are rotatably engaged with the shafts 14, after which the knobs 4 and the shafts 14 will rotate together.
The knobs 4 are fixedly coupled to drums 16 which have conical portions and are provided inside of the front plate 4 so that the drums 16 are also freely shiftable over the operating shafts 14. The front edge of a locking plate 17 engages the conical surfaces of the drums. As is apparent from FIG. 2, the locking plate 17 is mounted between two side walls of the frame 2 so as to be freely swingably around its axis, and a biasing spring 18 urges the locking plate 17 so that the front edge thereof is pressed against the conical surface of the drum 16. The drum 16 should be so arranged that the largest diameter end of the conical portion is located adjacent to the inside surface of the front plate 5.
Rearwardly against the drum 16, a movable plate 19 is provided for each of the operating shafts 14, each plate 19 being freely slidable on its shaft 14. On the downwardly projecting end l9a of the movable plate 19, a contacting member 20 is fixedly attached. On the contacting member 20, a contacting surface 20a is formed which contacts with the upper surface of the printed circuit plate 10. For allowing the axial movement of the projecting end 19a along the operating shaft 14 and for restricting its rotation when the shaft 14 is rotated, a groove 21 is provided on the printed circuit plate 10 at the corresponding position, in which the end 19a is slidably received (see Fig. 4).
Rearwardly of the movable plate 19 on the operating shaft 14, a biasing spring 22 is provided which urges the knob 4, drum 16 and the movable plate 19 forwardly.
FIGS. 2, 2A and 2B illustrate one structure by means of which the requisite mounting and operative connection of the knobs 4 on the shaft 14 is disclosed. The knob 4, with its associated drum 16, is provided with an axial passage 4 through which the shaft 14 is slidable. That shaft 14, at its outer end, is provided with a tip portion 14" of reduced diameter joined to the shaft proper 14 by a tapered section 14" which is toothed. The knob 4 is provided near its outer end with a reduced size passage 4" which communicates with the main passage 4 by means of an outwardly tapered section'4. When the spring 22 acts on the plate 19 to move the knob 4 and its associated drum forwardly, or to the left as shown in FIG. 2, the tapered knob and shaft portions 4" and 14" are separated and only the tip of the shaft portion 14" is received within the knob passage 4", as shown in FIG. 2A. Under these circumstances rotation of the knob 4 will not be transmitted to the shaft 14. When, however, the knob 4 is pushed inwardly against the action of the spring 22 to its position illustrated in FIG. 23, where the locking plate 17 has engaged behind the drum 16, the matingly toothed tapered surfaces 14" and 4" of the shaft and knob respectively will engage one another, after which rotation of the knob 4 will be transmitted to the shaft 14 and will drive the latter in rotation.
In the above described control device, when a constant voltage is applied between the lead wires 12a and 12b, that voltage is then applied across the resistors 1 1. If one of the knobs 4 is pushed rearwardly, the front edge of the locking plate 17 is lifted upward along the conical surface of the drum 16, and ultimately the forward end surface of the drum 16 is locked by the downwardly directing tip of the locking plate 17 In this way, forward movement of the knob 4 and the drum 16 due to the biasing spring 22 is blocked.
At this time, the movable plate 19 together with the drum 16 is also shifted along the operating shaft 14, and if the drum is blocked as described above, the movable contact provided on the movable plate 19 contacts with both of the fixed contacts 13a and 13b, whereby the contacts 13a and 13b are electrically connected together.
On the fixed contact 13b, there is provided a conductive plate 13b (see Fig. 4) mechanically and electrically contacting the operating shaft 14. Accordingly, if an external element (such as a varactor diode) isconnected between the lead wires 12c and 12b (or 12a), a voltage created between the lead wire 12b and the sliding member 15 on the resistor l1 is applied across that external element. To be more specific, when the knob 4 is pushed rearwardly, an electric circuit through the external element is actuated.
Thereafter, the knob 4 may be rotated, rotating the operating shaft 14 in a desired direction. As a result the sliding member 15 is shifted along the guiding portion 14' of the operating shaft 14 so that the contacting position thereof along the resistor 11 is changed. Ac cording to the adjusted position of the sliding member 15, the potential difference between the lead wires 12b and 120 is changed. That is, the potential difference is controlled by turning the knob 4 through a desired angle.
When a varactor diode is connected between the lead wire 12b and 120, the capacitance of the varactor diode is thus controlled by turning a knob 4 in this control device.
Furthermore, since the lead wires 12a, 12b and 120 are arranged in specified sequence at a predetermined distance from one another at the edge of the printed circuit plate 10, the connection of this device to the outside circuit may be carried out by simply inserting the circuit plate into a conventional printed circuit connector (not shown).
In this example, because the contact point of the sliding member and the conducting plate 13b are electrically connected through the operating shaft 14, 14, at least the surface portions of the operating shafts 14, 14' must be made of an electrically conductive material. I
When it is desired to release the control device from its operating condition, a knob 4 for any other channel should be pushed slightly. In this way the tip of the locking plate 17 is lifted along the conical surface of the drum 16 belonging to the depressed shaft 14 against the spring force of the biasing spring 18, and the locking of the operating shaft 14 is thereby released. The knob 4, drum 16v and the movable plate 19 of the operating shaft 14 will then be returned to their original projected position by the action of the biasing spring 22, whereby the movable contact 20a will be disengaged from the fixed contacts 13a and 13b, and the voltage applied across the lead wires 12b and 12c will be nullified. I
The construction and operation of the indicator will now be described with reference to FIGS. 5 through 7.
As already described, the indicators comprise an indicator plate 3, windows 7 provided on the indicator plate 3, and flexible ribbons 9 movable up and down inside the windows 7. Since the indicator plate 3 is detachably mounted on the frame 2 by means of, for instance, engageable joints or machine screws, the indicator plate 3 may be removed if desired.
As described before, the number and location of the windows 7 are sodetermined by the number of the channels and the locations of the windows 8 provided in the element cover 1 for exposing the sliding members 15. On both sides of each of the windows 7, vertically directing grooves 71 are provided in parallel with the windows 7, and in these grooves 71, a flexible ribbon 9 is inserted so that each ribbon 9 is freely slidable inside of its groove 71.
It should be noted that the ends 91 of the ribbons9 can be seen through the windows 7, and that the other ends 92 thereof are fixed to the upper end portions 15 of the sliding members 15. To be more particular, the ribbons 9 are bent at the positions where the ribbons are led out of the grooves 71 and received in other grooves 81 which are provided on both sides of the win dows 8 in alignment with the grooves 71.
With this arrangement, when the sliding member 15 is shifted as a result of the rotation of the corresponding knob 4, the ribbon 9 is moved together with the sliding member 15, and the movement of the ribbon 9 can be detected by the location of the end 91 of the ribbon 9 as seen in the window 7.
Accordingly, if a graduated scale is provided on one side of the window or windows 7 or on the front panel of a casing wherein the control device is encased, the rotation of the knob 4 can be adjusted by observing the location of the end 91 of the ribbon 9 relative to the graduated scale.
FIG. 8 shows another example of the control device, wherein the angle between the indicator plate 3 and the frame 2 is altered from that of the above described example. Since all of the component parts and the construction are similar to the first embodiment of the invention shown in FIGS. 1 through 7, except the above described feature of the different angle, further description of this embodiment is 'not required.
In FIG. 9, there is indicated an application of this control device in a television receiver, wherein the embodiment of the invention shown in FIGS; 1 through 7 is combined in the receiver as shown in FIG. 9A and the embodiment of FIG. 8 is combined in the receiver as shown in FIG. 98. It is seen that, in the case of FIG. 9A, the knobs 4 and the indicating windows 7 are arranged in the same plane, and, in the case of FIG. 9B, the plane including the indicating windows 7 and the plane wherein the knobs are arranged are spanning an angle.
As described before, when the indicator plate 3 and the ribbons 9 are removed, the control device can be used per se as a thin type control device. In such an application, the exposed ends 15' of the sliding members 15 in the windows 8.in the element cover 1 act as an indicator in this control device. FIG. 9C indicates this kind of application. It should be noted that the plane including the windows 8 and the plane in which the knobs 4 are arranged are intersecting perpendicularly.
Referring again to FIG. 5, there is indicated a knob 6 for operating an AFC switch which is in itself a rotary switch. The detailed construction of the AFC switch will now be described with reference to FIGS. 10, 11 and 12.
In the frame body 101, are... are provided three engaging positions for a spring which correspond to three apices of a triangle. The first engaging position 102 engages with one leg 105a of a spring 105 bent into a V- shaped configuration. The second and third engaging positions 103 and 104 engage with an intermediate portion of the other leg of the spring 105 as will be described hereinafter. The end lb of the other leg of the spring 105 engages with a bifurcated engaging arm 111 of an operating cam 106 which is freely rotatably mounted on the frame body 101.
The circumferential surface of the operating cam 106 contacts with a resilient contact piece 107, one end of which is fixed to an insulating plate (not shown) and the other end of which is left free. The intermediate portion between the fixed end and the free end of the contact piece 107 is curved as designated by numeral 114.
At another position on the insulating plate opposing the free end of the contact piece 107, a fixed contact 110 is provided. When the curved portion 114 of the contact piece 107 is not depressed by a projection 112 of the operating cam plate 106, the free end of the contact piece 107 does not contact with the fixed contact 110 (see FIG. 12C). When the curved portion 114 is depressed, the free end of the contact piece 107 contacts with the fixed contact 110, whereby the switch is closed as shown in FIG. 12A.
The operating cam plate 106 has a central hole 113 which is fixed to a rotating shaft 108. The rotating shaft 108 is freely rotatably mounted on the frame body 101 through a hole 109. As is previously described, the three engaging positions 102, 103, and 104 form a triangle inside of which has been cut away so that a triangular hole 115 is bored through the frame body 101. Between the engaging positions 103 and 104 a convex guiding edge 116 toward the engaging position 102 is provided. An intermediate portion 105 c of the V- shaped spring 105 is guided along the convex guide edge 116.
When the rotating shaft 108 is rotated by means of 'a knob 6, the switch position may be shifted from its ON position indicated in FIG. 12A through an intermediate position as shown in FIG. 12B to the OFF position indicated in FIG. 12C.
In this case, since the spring 105 is once compressed a the intermediate position (FIG. 12B) through the convex guide edge 116, further turning of the knob 6 exceeding the maximum convex point allows the V- shaped spring 105 to expand again, and the leg 1050 is rapidly shifted to another engaging position 104. As a result, the operating cam plate 106 is quickly rotated, and the projected portion 112 of the cam plate 106 is rapidly released from the curved portion 114 of the resilient contact piece 107. The contact piece 107 thereby interrupts the engagement of the contact piece 107 with the fixed contact 1 10.
If it is desired to shift the rotary switch from its OFF position (FIG. 12C) to the ON position (FIG. 12A), the rotating shaft 108 may be simply rotated back to the original position by means of the knob 6.
It will be apparent that the rotary Switch indicated in Figs. 10, 11 and 12 may be employed as an AFC switch which is indicated merely by a knob 7 in Figs. 1 through 8. In such a case, the frame body 101 corresponds to 9., the front plate 5 of the frame body 2, and the insulating plate corresponds to the printed circuit plate 10.
With the above described construction, a control device having an AFC switch, an indicator for indicating the positions of the sliding members, and lead wires which may be connected to an outside circuit through a standard printed circuit connector may be obtained.
Although the present invention has been described with respect to preferred embodiments thereof, it will be apparent that various modifications may be made without departing the scope and spirit of the present invention.
1. A rotary switch comprising: a shaft freely rotatably mounted on a frame body; an operating cam plate fixed on an end of said rotating shaft; a cam portion provided on one part of said cam plate; a resilient contact piece kept in a normally contacting condition with said cam plate by its own resilience and one end of which is movable; a fixed contact provided opposingly to said movable end of said resilient contact piece; a spring of approximately V-shape and having one leg thereof engaged with first engaging means in said frame body and the other leg thereof being engaged with said operating cam plate; a second and a third engaging means provided in a relation, together with said first engaging position forming a triangle; said second and third engaging means defining a convex guide edge therebetween and a leg of said V-shaped spring engaging said guide edge; whereby, when said rotating shaft rotates, the control of said resilient contact piece due to said cam portion of said cam plate is made stepwise and the switching motion of said resilient contact piece is made instantaneous. I
2. A rotary switch adapted to move a movable contact into and out of operative engagement with a fixed contact comprising a frame, a rotary member rotatably mounted on said frame, means on said rotary member operatively engaging said movable contact for moving said movable contact into and out of engagement with said fixed contact in response to rotation of said rotary member, spring means adapted to move between two detented positions on said frame, means operatively connecting said rotary member to said spring means for movement therewith between said two detented positions whereby rotation of said rotary member in one sense is effective to move said spring means to one of said detented positions and to simultaneously move said movable contact into operative engagement with said fixed contact and rotation of said rotary member in the opposite sense is effective to move said spring means to the other of said detented positions and to simultaneously move said movable contact out of engagement with said fixed contact.
3. A rotary switch for moving a movable contact into and out of engagement with a fixed contact comprising a frame, a rotary member rotatably mounted on said frame, spring means mounted at one end on said frame and having its other end movable with respect to said frame between first and second detentable positions, means connecting said rotary member to said other end of said spring means in driving relationship for movement therewith thereby to limit the rotation of said rotary member to that portion of its rotary travel corresponding to said first and second detentable positions of said spring means, and means on said rotary member operatively engaging said movable contact and adapted to move said movable contact into and out of engagement with said fixed contact as said spring means is moved to said first and second detentable positions, respectively.
4. The rotary switch of claim 3, wherein said spring means comprises a resilient member having two legs normally biased outwardly away from each other, means on one of said legs for engaging said frame at a relatively fixed pivot point and means on said other leg for engaging said rotatable member in drivable relationship therewith, and cam means on said frame defining said two detented first and second detentable positions of said other leg.
5. The rotary switch of claim 3, wherein said means for moving said movable contact comprises projection means extending radially outwardly from said rotary member.
6. The rotary switch of claim 4, wherein said means for moving said movable contact comprises projection means extending radially outwardly from said rotary member.
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