US 3855521 A
A voltage adapting apparatus which has a transformer with primary and secondary windings, one of which has a plurality of separate windings and taps which are independent from each other, and a rotary switch for interconnecting the taps to an external, commercial, A.C. source so that a constant voltage is obtained at the transformer secondary winding when any one of a plurality of A.C. voltages is applied through the switch to the primary windings. The switch includes a terminal board with a central fixed terminal, a plurality of fixed terminals arranged in plural coaxial circles around the central terminal and a rotary insulating member which has a pair of spring mounted short circuit contacts arranged parallel to each other, the first short circuit contact connecting with the central terminal and with one of a plurality of solid terminals intersecting one of the plural coaxial circles and the second short circuit element being selectively connected to two or more of the fixed terminals on another of the coaxial circles.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Kiuchi [451 Dec. 17, 1974 TRANSFORMER HAVING SWITCH MEANS FOR CAUSING SERIES OR PARALLEL CONNECTION BETWEEN PLURAL PRIMARY OR SECONDARY WINDING Inventor: Masao Kiuchi, Saitama-ken, Japan Assignee: Sony Corporation, Tokyo, Japan Filed: May 21, 1973 Appl. No.: 362,061
Foreign Application Priority Data May 24, 1972 Japan 47-60771[U] US. Cl. 323/49, 200/11 G, 200/11 TC, 307/17, 323/43.5
Int. Cl. ..L G05f 3/04 Field of Search ..'200/1l TC, 11 EA, 11 G, 200/11 H, 11 .l, 11 K; 323/44 R, 48, 49, 50, 62; 307/17, 37, 71
References Cited UNITED STATES PATENTS Primary Examiner-James R. Scott Attorney, Agent, or Firm--Lewis H. Eslinger; Alvin Sinderbrand 5 7 ABSTRACT A voltage adapting apparatus which has a transformer with primary and secondary windings, one of which has a plurality of separate windings and taps which are independent from each other, and a rotary switch for interconnecting the taps to an external, commercial, A.C. source so that a constant voltage is obtained at the transformer secondary winding when any one of a plurality of AC. voltages is applied through the switch to the primary windings. The switch includes a terminal board with a central fixed terminal, a plurality of fixed terminals arranged in plural coaxial circles around the central terminal and a rotary insulating member which has a pair of spring mounted short circuit contacts arranged parallel to each other, the first short circuit contact connecting with the central terminal and with one of a plurality of solid terminals intersecting one of the plural coaxial circles and the second short circuit element being selectively connected to two or more of the fixed terminals on another of the coaxial circles.
6 Claims, 16 Drawing Figures wTB Olttotil PATENTEBBECI mm I sum 20; 4
BETWEEN PLURAL PRIMARY OR SECONDARY WINDING BACKGROUND OF THE INVENTION The present invention relates generally to voltage I adapting devices and more particularly to such adapting devices which have a transformer and a voltage selecting switch for producing a constant A.C. output voltage from a plurality of different commercial A.C.
The A.C. voltages of different commercial systems vary greatly. For example in some parts of Europe the commercial electric power source is 220 volts while in other parts of Europe it is 240 volts. In the United States and some other western countries it is 1 volts. Furthermore the voltage may vary even in the same country. 1
When a traveler goes from one country to another with an electric appliance such as a magnetic taperecorder, a radio or the like, the appliance must be adapted to'operate on the different commercial voltages because the actual operating voltage used byv the appliance is a set, predetermined voltage.
It is still another object of the invention to provide a voltage adapting apparatus which does not require a Various voltage adapting devices have been previ- I ously proposed which convert an electrical appliance designed ,to operate on one voltage to operate on a different voltage. In some of these prior art devices the adapting circuit is built into the appliance itself while in other devices it is separate from it and includesa rectangular plug terminal board with a jack base plate attached to the housing of the apparatus and a transformer connected to the jack. Unfortunately such ap-- paratus often include detachable parts which may become lost, rendering the apparatus useless. Furthermore the changing of the voltage adapting apparatus from one country to the next is a relatively complicated operation. Still another disadvantage of some prior art voltage adapting devicesis that if it is built in the electronic appliance it consumes excess space and requires excessive recesses in the housing of the appliance.
SUMMARY OF THE INVENTION These and other disadvantages are overcome by the present invention of a voltage adapting apparatus comprising a terminal board-having a plurality of conduc tive terminals arranged in co-axial circles, a transformer having a plurality of windings and taps on each winding to be connected to the plurality of conductive terminals in selected patterns and a rotary insulating member rotatably supported by the terminal board and having connectors for connecting the conductive terminals in pre-selected patterns so that the separate windings and taps of the transformer are connected variously in series or in parallel configurations to the external commercial A.C. source whereby a constant output voltage is obtained for any one of a plurality of A.C. input voltages.
Accordingly it is one object of the invention to prolarge attachment plug to the appliance with which it is intended to be used.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of certain preferred embodiments of the invention, taken in conjunction with the accompanying drawings. I
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic circuit diagram of one embodiment of the invention;
FIGQ2 is a top plan view of the selecting switch of the embodiment of FIG. I;
FIG. 3 is a side view of the selecting switch depicted in FIG. 2;
FIG. 4 is a top plan view of a terminal board forming a part of the selecting switch of the embodiment of FIG. 1;
FIG. 5 is a cross-sectional view taken generally along the line V\/ in FIG. 4;
FIG. 6 is a top plan view of a rotary element forming a part of a selecting switch depicted in FIG. 2;
FIG. 7 is a cross-sectional view'taken generally along the line VII-VII in FIG.'6; 7
FIGS. 8A, 8B and 8C are perspective views of the short circuiting elements and a ball and spring arrangement provided for use in the switch depicted in FIG. 2, respectively;
FIGS. 9 to 12, inclusive, are schematic circuit diagrams showing the effective connections of the transformer for various positions of the rotary selecting A former for a second embodiment of the invention; and
vide a voltage adapting apparatus which is easily oper- FIG. 14 is an enlarged, diametrical sectional view of the assembled selecting switch illustrated by FIGS. 2 to SC, inclusive.
DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS Referring now more-particularly to FIG. I a transformer TR according to the present invention has a primary winding L, which is divided into afirst winding member L and a second winding member L The first winding member L has a reference terminal or tap r, at one end, a tap at its other end and a tap r, at an intermediate point between the taps t, and 1 For any given output voltage from the secondary winding L which would depend on the number of turns in the winding L the voltages to be applied to the taps t I, and t; of the winding L would typically be 0, 20 and volts, respectively. A second winding L has a reference terminal or tap t, at one end, a tap 1 at its other end and an intermediate tap 1 Again, with respect to a desired outputvoltage from the secondary winding L the alternating current voltages which typically would be applied to the taps t t and t are 0, I I0 and 130 volts, respectively. As will be explained in greater detail hereinafter the taps on the windings I. and L are variously interconnected with each other by means of a switch SW to be in parallel or in series to provide a constant output voltage at the secondary winding L,
for a plurality of alternating current input voltages from a wall plug 3.
The selecting switch SW includes a terminal board 1 having a plurality of solid, electrically conductive terminals and a rotary insulating button 2 which has affixed to it a plurality of short circuit elements S, and S for short circuiting selected ones of the solid conductive terminals.
The terminal board 1 is formed from a substantially disc-shaped insulator and has a circular recess 1A (FIG. 5) in its center portion. At the bottom of the circular recess 1A there are provided a plurality of solid contacts T,, T T T and T plus a center contact T The contact T is spaced from the center terminal by a predetermined distance which forms the radius of a hypothetical circle C,. The terminal T is located approximately in the three o'clock position as viewed in FIG. 4. The other terminals are located at a slightly larger radius from the center terminal T along a hypothetical circle C If the position of the terminal T is taken as the positions of the terminals T T and T, are at approximately 45, 225 and 315, respectively.
The terminal T, is located so as to extend in such a manner that it intersects the circle C, at a rotary position of approximately 90 and intersects the circle C at a rotary position of approximately. 135. The portion of the terminal T, which intersects the circle C, is designated T, and the portion which intersects the circle C is designated T,,,. The terminals T,T,,, inclusive, are provided with outer leads T,T,,', respectively, which project beyond the rear surface 1B of the terminal board 1, as is more clearly shown in FIGS. 3 and 5. These leads T, T are connected to the terminals 1, I, of the coil L, of the transformer TR as follows:
Terminals of Transformer TR Furthermore, the terminal lead T, and the terminal lead T are connected to the separate leads of the utility plug 3.
Referring now more particularly to FIGS. 6 to 8B, the rotary button 2 of the selecting switch SW includes an insulating disc-like base portion 2A and a circular, post-like projection 28 as illustrated in FIGS. 6 and 7. The portions 2A and 2B are made integrally from an insulative material such as phenol resin.
A low height, short-circuit element S, (FIG. 8B) is inserted in a shallow recess 2a in the bottom portion of the button 2, as shown on FIG. 14, so that one end of the short-circuit element 8,, such as a contact 8,, will contact the central terminal T and the other end of the element 5,, such as a contact S will contact either the terminal T or the'end of the terminal T, when the button -2is rotated. A second or high-height, short-circuit element S is fitted in a recess 212 at the outer perimeter of the button 2, as shown on FIG. I4, and is generally arranged parallel with the recess 2a so that its opposite ends, which have contacts 5,, and S will interconnect pairs of the contact terminals T T and T, which are at with respect to each other. The short-circuit elements S, and S are formed of a conductive material such as phosphor bronze plate which is bent to have a substantially V-shape.
The rotary button 2 has a bore 2c into which a spring Sp is fitted. A metal ball B0 is then placed on top of the spring to form a stop member for the rotary switch as will be explained in greater detail hereinafter. The portion 2B has'an elongated groove or slit 2:] in its upper surface which is designed to receive, for example, a coin to facilitate the rotation of the rotary button 2. The rotary button 2 is further marked with a recessed arrow 2e on the top surface of the member 28 for indicating the voltage (not shown) corresponding to the rotated position of the rotary button 2.
The rotary button 2 is rotatably assembled to the terminal board 1 by means of a metal cover 3 which has an opening 3a in its center'to receive the projecting portion 28 of the button 2. The metal cover also has four slits 3d, 3e, 3f and 3g arranged at 90 angles about the opening 3a. The positions of the slits are designed to engage with the spring biased metal ball Bo and to stop the rotary button 2 at predetermined positions corresponding to the switch contacts. The cover 3 further has tangs 3h and bores 3b and 3c which correspond to bores la and lb in the terminal board 1. Referring in detail to FIG. 14, it will be seen that the assembly of the switch SW is as follows:
The short-circuit elements S, and S are inserted in their respective recesses 2a and 2b in the rotary button 2. The button portion 2A is inserted into the recess 1A of the terminal board I and the spring Sp and the metal ball B0 areinserted into the hole 20 of the rotary button 2. The cover 3 is thereafter mounted on the terminal board 1 from above in such a manner that the opening 3a in the cover coincides with the projecting member 28 of the rotary button 2 to hold the rotary member in. rotatable engagement with the terminal board 1. Thereafter the tangs 311 of the cover 3 are bent downwardly to engage with engaging portions 1C and ID of the terminal board 1, respectively. The outer leads T, through T6, inclusive, of the terminal board I are thereafter interconnected with the terminals r, 1,, of the transformer TR and the leads of the power plug 3 in the manner described above.
The selecting switch SW has therefore been assembled with no screws or the like and is thereafter attached to the electronic appliance by means of screws through the bores 3b and 3c in the cover 3 and the bores la and lb of the terminal board I.
When the rotary button 2 is rotated relative to the terminal board I to a position such that the shortcircuit element S, forms a connection between the terminals T, and T and the short-circuit element S forms a connection between the terminals T, and T as shown in FIG. 4, the transformer taps t and 1 are connected to each other as are also the taps I and Accordingly, the connections among the terminals of the transformer TR and the electric power source plug 3 become as shown in FIG. 9. With these connections the portion of the first winding L,, between the taps t and 1,, and the portion of the second winding L, between the taps t and 1,, are connected in parallel with each other with respect to the power source plug 3. Thus when a voltage of volts of alternating current is supplied to the power source plug 3, a predetermined output voltage is produced across the secondary winding L of the transformer TR.
When the rotary button 2 is rotated 90 counterclockwise, as viewed in FIG. 4, from the first position so that the short-circuit element S connects only with the terminal T and the short circuit element S interconnects the terminals T, and T the transformer'taps t and t are connected together. Accordingly, the connection among the taps of the transformer TR and the power source 3 becomes as shown in FIG. in which the portion of the second winding L between the taps t and t and the portion of the first winding L between the taps t and t are connected in series with respect to the power source plug 3. Thus when a voltage of 220 volts A.C. is supplied from the power source plug 3 the predetermined voltage is again produced across the secondary winding L of the transformer TR.
When the rotary button 2 is rotated 90 in the counter-clockwise direction as viewed in FIG. 4 with respect to the second position, the short-circuit element S is again only in contact with the terminal T and the short-circuit element S interconnects the terminals T, and T so that the taps t and of the transformer TR are connected together. This effectively connects the taps of the transformer TR to the power source plug 3 as shown in FIG. I I in which the portion of the winding L between the taps t, and t and the portion of the winding L between the taps t and 1;, are connected in series with respect to the power source plug 3. Thus when a voltage of 240 volts is supplied to the power source plug 3 the predetermined output voltage is still produced across the secondary winding L of the-transformer TR. a
When the rotary button 2 is rotated 90 counterclockwise as viewed in FIG. 4 relative to the third position, the short-circuit element S, interconnects the terminals T and T and the short-circuit element S interconnects the terminals T and T At this rotary position the transformer taps t and 1 are shorted together and the taps and r, are shorted together. Accordingly, the connections among the taps of the transformer TR with respect to the power source plug 3 become as shown in FIG. 12 in which the portion of the winding L between the terminals r, andn, and the portion of the winding L between the terminals 1, and t;, are connected in parallel with respect to the terminals of the power source plug 3. Therefore, when a voltage of 130 volts A.C. is applied to the power source plug 3 the predetermined voltage is produced across a secondary winding L of the transformer TR.
As is apparent from the above description, with the present invention the rotary button 2 may be rotated relative to the terminal board 1 to a plurality of positions in correspondence with input voltages of I10, 220, 240 and 130 volts A.C. to obtain the same predetermined output voltage across the secondary winding L of the transformer TR.
Although the above description is with reference to an embodiment in which the primary winding of the transformer is divided into two separate windings with a plurality of taps, in other embodiments the primary winding of the transformer may be composed of three or more windings.
Furthermore, as is illustrated in FIG. 13, the switch SW may be interconnected with a secondary winding L, which is composed of two separate windings L and L having a plurality of taps. With such a transforrner'TR' there is only a single primary winding L, which is connected to the power source terminal 3. In this embodiment the terminals of the switch SW are interconnected in a manner similar to that in the embodiment described above so that the same output voltage is derived from the switch SW for a plurality of input A.C. voltages to the primary winding L,.
In still other embodiments the solid terminals of the terminal board 1 may be disposed in three or more coaxial circles. In these embodiments the number of short circuit elements is increased.
The terms and expressions which have been employed here are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions, of excluding equivalents of the features shown and described, or portions thereof, it being recognized that various modifications are possible within the scope of the invention claimed.
What is claimed is:
1. A voltage selecting apparatus, comprising:
a transformer having a primary winding and a secondary winding, one of which includes a plurality of separate windings, each of said separate windings having a plurality of taps;
housing means having a plurality of fixed terminals predetermined ones of said fixed terminals being disposed about the periphery of at least two individual coaxial circles and one of said fixed terminals being disposed at the center of said coaxial-circles;
conducting means for connecting each of said fixed terminals to a tap;
means for supplying an AC voltage from an external source to said transformer; and
rotary button means mounted for rotation with respect to said housing and having at least two short circuit members supported in said rotary button means and rotatable therewith, a first of said shortcircuit members defining a chord of one of said coaxial circles to thereby selectively short-circuit a pair of said fixed contacts disposed about the periphery of said one coaxial circle in accordance with the rotary position of said button means, and a second of said short-circuit members being in contact with said one fixed terminal disposed at said center of said coaxial circles and being substantially pivotable thereabout to thereby selectively short-circuit said one fixed terminal and a selected fixed terminal disposed about the periphery of another of said coaxial circles in accordance with said rotary position of said button means, such that preselected ones of said taps are electrically interconnected in predetermined circuit configurations whereby a single predetermined output voltage is derived from said transformer when said button means is rotated into corresponding rotary positions associated with different AC voltage magnitudes supplied to said transformer.
2. A voltage selecting apparatus according to claim 1, wherein the housing means has a circular recessin which the fixed terminals are disposed and the rotary button means is rotatably retained in the recess.
3. A voltage selecting apparatus according to claim 2, wherein the rotary button means is provided with a plurality of recesses in which the short-circuit members are disposed.
serted in the hole, and the spring biased ball being engageable with the slits of the cover means to lock the rotary button means at predetermined rotary positions.
'6. A voltage selecting apparatus according to claim 5, wherein the rotary button-means has formed on its upper surface an elongated groove to facilitate the manual rotation of the rotary button means.