US3755764A

US3755764A - Antenna coil support for a tuner

Info

Publication number: US3755764A
Application number: US00200695A
Authority: US
Inventors: T Suzuki
Original assignee: Alps Electric Co Ltd
Current assignee: Alps Alpine Co Ltd
Priority date: 1970-12-10
Filing date: 1971-11-24
Publication date: 1973-08-28
Anticipated expiration: 1990-08-28

Abstract

A tuner has an insulating member with a surface upon which is disposed a first electrically conducting element. A second electrically conducting element such as an antenna coil is mounted and directly supported on said member proximate said first element by a support means so as to be electromagnetically coupled thereto. Preferably, the second element has two reaches and said support is substantially U-shaped with a central aperture within which the reaches are disposed.

Description

I United States Patent 1 [111 3,755,764

Suzuki 1 Aug. 28, 1973 [54] ANTENNA COIL SUPPORT FOR A TUNER 3,512,110 5/1970 Clar 333/10 [75] Inventor: Takeo Suzuki, Tokyo,.lapan [7 3] Assignee: Alps Electric Co., Ltd., Tokyo, Japan Primary Examiner-Raul L. Qenglgr V W [22] Filed: No 24, 1971 A'ttifni y' iviaiweii James and Harold James [21] Appl. No.: 200,695

[30] Foreign Application Priority Data ABSTRACT Dec. 10, 1970 Japan 45/l23280 A tuner has an insulating member with a surface upon [52] US. Cl. 334/45, 248/74 A, 333/24 R, which is isposed a first electrically conducting ele- 334/15 ment. A second electrically conducting element such as [51] Int. Cl. H03j 5/02 n n nn il i m n e and directly supported on [58] Field of Search ..334/4l-45, l5 Said m r proximate said first element by a support 333/24 R 10 84 R; 248/63 R 73 means so as to be electromagnetically coupled thereto. 74 A; 317/101 DH Preferably, the second element has two reaches and said support is substantially U-shaped with a central ap- [56] References Cited erture within which the reaches are disposed.

UNITED STATES PATENTS 3,154.28] 10/1964 Frank 248/74 A X 17 Claims, 3 Drawing Figures COUPL/NG SL075 ANTENNA COIL SUPPORT FOR A TUNER BACKGROUND OF THE INVENTION This invention relates to television tuners, and more particularly to supports for antenna coils of the tuners.

Tuners are a common component of electronic circuits which are used to receive desired frequencies. The tuner is connected to receive signals from an antenna and to select or tune to a signal having a particular frequency. To accomplish this, tuners have at least one tuned circuit that is capable of being tuned to the frequency of the desired signal. The tuned circuit often comprises at least two elements having capacitance and inductance respectively, which can resonate at the desired frequency in accordance with the values of their capacitance and inductance. If the tuner is designed to receive UHF signals, the inductive element often comprises a transmission line having a central conductor, while the capacitive element may be a diode that has a capacitance that varies in accordance with an applied voltage. Therefore, by controlling the voltage applied to the diode, one can control the resonant frequency of the tuned circuit.

The signals are received by an antenna and applied to an antenna transmission line. To apply the signals in the antenna transmission line to the tuned circuit, it is customary to have an antenna coil connected to the transmission line to receive the signals thereon and to dispose the coil near the central conductor so as to induce the signals present on the antenna coil into the resonant circuit. Since in the prior art the only supports for the antenna coil are the antenna terminals on the tuner frame to which the antenna coil is soldered, the antenna coil is unstably mounted and can vibrate and possibly touch the central conductor or the frame of the tuner. This obviously will render the tuner at least partially inoperative. The prior art attempted to overcome this defect by placing an insulating tube around the antenna coil so that it will not touch the other tuner components. However, this still permits the antenna coil to vibrate and therefore change the coupling between itself and the central conductor, and it still permits noise and variations in the amplitude of the received signal to occur. In addition, the thickness of the tube prevents a close coupling between the antenna coil and the tuning line.

It is therefore an object of the present invention to minimize noise and signal strength amplitude variations in a tuner.

It is a further object to physically stabilize an antenna coil with respect to a tuned line in the tuner.

It is a still further object to so mount an antenna coil in a tuner as to enable it to be very closely spaced from a tuned line, thereby to provide high electromagnetic coupling therebetween.

SUMMARY In brief, these and other objects are achieved by providing a support means that in turn is directly supported by an insulating circuit board. To that end, the tuner comprises an insulating board member having a surface with a first electrically conducting element disposed thereon. A support is directly mounted on the member and engages and carries a second electrically conducting element that is adapted to be electrically coupled to the first conducting element. The support so engages the second element as to reliably stabilize it with respect to the first element, and noise and signal amplitude variations are eliminated. Preferably, the second element has two separated reaches and said support comprises a substantially U-shaped body with a central aperture for clampingly receiving said reaches, and thus increasing the stability of said mounting. Firm clamping action is ensured by reason of the interengagement between the support and the board. The second conductive element is clamped near its free end by the support, thus further ensuring relatively rigid stabilization.

The surface of the insulating board can be substantially planar, and said first element can be a flat conducting strip at least partially disposed on the surface. Desirably, an insulating layer can be disposed between the conducting strip and the second element so that the coupling between said elements can be high without their contacting each other.

To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to a support means for an antenna coil as defined in the appended claims, and as described in this specification, taken in conjunction with the drawings in which:

FIG. 1 is a top view of a tuner in accordance with the present invention with its top cover removed;

FIG. 2 is a three-quarter perspective view showing an antenna coil support device in place in said tuner; and

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2 showing details of the antenna coil support device itself when mounted on a circuit board.

Conductive casing 10 has a shield 12 disposed in it and they, together with the top and bottom plates (not shown), define a cavity 14. Shield 12 has slots 13 defined therein to electromagnetically couple signals in cavity 14 to an adjacent cavity (not shown). A printed circuit board substrate 16 is placed in the cavity and has a conducting strip 24, which can be made from the copper foil of the printed circuit board, extending on the top of board 16. An insulating sheet or resist 18 is disposed over most of the conductor 24. For reasons that will be explained below, this sheet or resist 18 is relatively thin. As shown by dotted lines in FIGS. 2 and 3, substrate 16 has two holes, 20 and 22 that extend therethroug h. They are adapted to receive lugs from the antenna coil support device as will be more fully described below. One end of conductor 24 is connected to one lead of a voltage variable capacitance diode 26 whose other lead is connected to the frame 10. That same end of conductor 24 is also connected to the terminal 28 which is adapted to receive a DC voltage to vary the capacitance of diode 26. The other end of conductor 24 is connected through a bypass capacitor 30 to the case 10. This capacitor 30 grounds said other end for radio frequencies, but prevents the grounding of the DC voltage that is applied to the diode 26. In this particular embodiment, the resonant circuit comprises the conductor 24, cavity 14, and diode 26, and is of the coaxial half-wave type. By varying the voltage applied to terminal 28, the resonant frequency of said resonant circuit can be changed. The value of the voltage is determined by a channel selection knob and its associated circuitry (not shown) in accordance with the wishes of the user of a television set.

Antenna terminals 32 are disposed at one end of the frame 10 and are adapted to be connected to an antenna transmission line (not shown) that is in turn connected to an external antenna (not shown). Connected at one of its ends to the terminals 32 is an antenna coil 34 having upper and lower reaches 34a and 34b. These reaches 34a and 34b are held above said conductor 24 by a support device 36 that is in turn directly supported by substrate 16 in accordance with the present invention, as will be more fully described below.

In operation, the antenna will pick up signals of many different frequencies and apply them through the antenna transmission line to the terminals 32. These signals will be applied by antenna coil 34 to said resonant circuit. A voltage is applied to terminal 28 and hence diode 26, by said channel selection circuitry (not shown), and it has a magnitude such as to tune the resonant circuit to a desired frequency. Since said resonant circuit is tuned to said desired frequency, only that frequency will be selected by the tuner and be passed through the slots 13in shield plate 12 on to the next stage. This stage usually is an amplifier or a mixer.

The structure of the antenna coil support 36 is best shown in FIG. 3. It comprises a generally U-shaped member formed of insulating material having a certain degree of resiliency. It comprises opposing portions 36a and 36b connected by a linking portion 360. These portions 36a, 36b, and 36c define a central aperture 38. Communicating with this central aperture 38 are

recesses

40 and 42 adapted to receive upper and lower reaches 34a and 34b respectively of the antenna coil 34. It will be noted that recess 42 communicates via slot 43 with the space external to support 36 for ease of insertion of coil 34 into support 36.

Arms

44 and 46 are integral with the rest of the support 36 and project laterally therefrom and lugs 48 and 50 respectively depend from them. Lugs 48 and 50 are slotted at 52 and 54 and have

ledges

56 and 58 respectively so that they can be compressed to be inserted into holes and 22 respectively, after which they snap out so that

ledges

56 and 58 catch onto the other side of the substrate 16. The spacing between

ledges

56, 58 and the lower surfaces of

arms

44 and 46 is closely the same as the combined thicknesses of board 16 and layer 18. In this way when the lugs 48 and 50 are snap-received through the

holes

20 and 22 the support 36 is firmly mounted on and directly supported by the board 16.

The antenna coil 34 is associated with the support 36 before the latter is mounted on the board 16. The coil 34 is passed through the slot 43 into the control aperture 38 so that its reaches 34a and 34b register with the

recesses

40 and 42 respectively. The support portions 36a and 36b spread to facilitate this assembly. Preferably, the support 36 is located along the coil 34 so as to be near its free end, with the

holes

20 and 22 being appropriately located on the board 16 relative to the conductor strip 24. Thereafter, when the lugs 48 and 50 are pushed through the

holes

20 and 22 respectively, the assembly of support 16 and coil 34 will be firmly and positively held in position on the board 16. The

holes

20 and 22 are so spaced from one another that when the lugs 48 and 50 are received therein the support portions 36a and 36b will be moved toward one another, thereby to positively clamp the coil reaches 34a and 34b in the

recesses

40 and 42 respectively. Hence vibration of the coil 34, or any shifting of its position relative to the conductor 24, is reliably prevented. In addition, the presence of the insulating sheet or resist l8 permits the coil reach 34b to be very closely located relative to the conductor strip 24, thereby to maximize the inductive coupling therebetween, without any danger that the two conductors will touch one another.

The support 36 can be very inexpensively made by molding of some suitable insulating synthetic. It may be assembled with antenna coil 34 and with board 16 simply and rapidly even by unskilled personnel. Hence it is very well adapted for assembly line production operations.

It will be seen that the present invention achieves a means for supporting an antenna coil in a tuner at or near both its ends that is very rugged, and hence minimizes vibrations of the antenna coil and its contacting of other components of the circuit. Therefore noise and signal amplitude variations are minimized. The support also allows a very close coupling between the antenna coil and the tuned circuit.

Although the present invention has been disclosed with respect to but a single embodiment, it is to be understood that many variations may be made therein, all without departing from the spirit and scope of the invention as defined in the following claims.

l claim:

1. A tuner comprising a reception stage including a variable resonant circuit, an insulating member having a surface, a first electrically conducting element forming a part of said resonant circuit disposed on said surface, a second electrically conducting element adapted to receive signals, and a self-sustaining support means normally separate from but secured to said member so as to be mounted on and directed supported by said member proximate said first element, said second element being mounted on and stably held to said support means proximate said first element, said second element being electromagnetically coupled to said first element by a substantially constant amount, thereby permitting said received signals to be induced into said first element, and means for connecting said first element to other elements of said resonant circuit.

2. A tuner in accordance with claim 1, wherein said member has at least one hole, said support means having at least one lug extending therefrom and engaging said hole, thereby to mount said support on said membet.

3. A tuner in accordance with claim 1, further comprising an insulating layer disposed between said first element and said support means, whereby said second element can be disposed near said first element to have a high coupling therebetween without said elements contacting each other. 4

4. A tuner in accordance with claim 1, wherein said support comprises a resilient material.

5. The tuner of claim 1, in which said second element comprises two separated reaches each of which is held by said support means and maintained separated thereby.

6. A tuner in accordance with claim 5, wherein said support means comprises a body having a central aperture, said second element being at least partially dis posed in said aperture.

7. A tuner in accordance with claim 6, wherein said support means is substantially U-shaped and comprises at least two portions disposed on opposite sides of said aperture and connected by a linking portion, said second element being clampingly engaged by said portions.

8. A tuner in accordance with claim 6, wherein said support means has two recesses communicating with said central aperture for frictionally receiving said reaches respectively of said second element.

9. The tuner of claim 6, wherein said support means is substantially U-shaped and comprises at least two portions disposed on opposite sides of said aperture and connected by a linking member, and a pair of lugs connected to said portions respectively, said member having a pair of holes for receiving said lugs respectively and being located so that each of said reaches of said second element is received between and clampingly engaged by said portions when said lugs are inserted into said holes.

10. A tuner in accordance with claim 1, wherein said support means comprises a body having a central aperture, said second element being at least partially disposed in said aperture. 1

11. A tuner in accordance with claim 10, wherein said support means is substantially U-shaped and comprises at least two portions disposed on opposite sides of said aperture and connected by a linking portion, said second element being clampingly engaged by said portions.

12. A tuner in accordance with claim 1, wherein said member comprises a printed circuit board.

13. A tuner in accordance with claim 12, wherein said board has a conducting foil disposed thereon comprising said first element.

14. A tuner in accordance with claim 1, wherein said second element is adapted to be secured to said tuner at one end and has a second end which is normally free, said support means engaging said second element adjacent said second end.

15. A tuner in accordance with claim 14, further comprising means for applying signals to said first end.

16. A tuner comprising a reception stage, an insulating member having a surface, a .first electrically conducting element disposed on said surface, a second electrically conducting element adapted to receive signals, and a self-sustaining support means normally separate from but secured to said member so as to be mounted on and directly supported by said member proximate said first element, said second element being mounted on and stably held to said support means proximate said first element, whereby said second element is electromagnetically coupled to said first element by a substantially constant amount, thereby permitting said received signals to be induced into said first element, and means for connecting said first element to said reception stage, in which said second element comprises two separated reaches each of which is held by said support means and maintained separated thereby, wherein said support means comprises a body having a central aperture, said second element being at least partially disposed in said aperture, wherein said support means has two recesses communicating with said central aperture for frictionally receiving said reaches respectively of said second element.

17. A tuner comprising a reception stage, an insulating member having a surface, a first electrically conducting element disposed on said surface, a second electrically conducting element adapted to receive signals, and a self-sustaining support means normally separate from but secured to said member so as to be mounted on and directly supported by said member proximate said first element, said second element being mounted on and stably held to said support means proximate said first element, whereby said second element is electromagnetically coupled to said first element by a substantially constant amount, thereby permitting said received signals to be induced into said first element, and means for connecting said first element to said reception stage, in which said second element comprises two separated reaches each of which is held by said support means and maintained separated thereby, wherein said support means comprises a body having a central aperture, said second element being at least partially disposed in said aperture, wherein said support means is substantially U-shaped and comprises at least two portions disposed on opposite sides of said aperture and connected by a linking member, and a pair of lugs connected to said portions respectively, said member having a pair of holes for receiving said lugs respectively and being located so that each of said reaches of said second element is received between and clampingly engaged by said portions when said lugs are inserted into said holes.

Claims

1. A tuner comprising a reception stage including a variable resonant circuit, an insulating member having a surface, a first electrically conducting element forming a part of said resonant circuit disposed on said surface, a second electrically conducting element adapted to receive signals, and a selfsustaining support means normally separate from but secured to said member so as to be mounted on and directed supported by said member proximate said first element, said second element being mounted on and stably held to said support means proximate said first element, said second element being electromagnetically coupled to said first element by a substantially constant amount, thereby permitting said received signals to be induced into said first element, and means for connecting said first element to other elements of said resonant circuit.

2. A tuner in accordance with claim 1, wherein said member has at least one hole, said support means having at least one lug extending therefrom and engaging said hole, thereby to mount said support on said member.

3. A tuner in accordance with claim 1, further comprising an insulating layer disposed between said first element and said support means, whereby said second element can be disposed near said first element to have a high coupling therebetween without said elements contacting each other.

6. A tuner in accordance with claim 5, wherein said support means comprises a body having a central aperture, said second element being at least partially disposed in said aperture.

10. A tuner in accordance with claim 1, wherein said support means comprises a body having a central aperture, said second element being at least partially disposed in said aperture.

16. A tuner comprising a reception stage, an insulating member having a surface, a first electrically conducting element disposed on said surface, a second electrically conducting element adapted to receive signals, and a self-sustaining support means normally separate from but secured to said member so as to be mounted on and directly supported by said member proximate said first element, said second element being mounted on and stably held to said support means proximate said first element, whereby said second element is electromagnetically coupled to said first element by a substantially constant amount, thereby permitting said received signals to be induced into said first element, and means for connecting said first element to said reception stage, in which said second element comprises two separated reaches each of which is held by said support means and maintained separated thereby, wherein said support means comprises a body having a central aperture, said second element being at least partially disposed in said aperture, wherein said support means has two recesses communicating with said central aperture for frictionally receiving said reaches respectively of said second element.