US1971315A

US1971315A - Coupling device

Info

Publication number: US1971315A
Application number: US546815A
Authority: US
Inventors: William P Lear
Original assignee: Meissner Manufacturing Co Inc
Current assignee: Meissner Manufacturing Co Inc
Priority date: 1931-06-25
Filing date: 1931-06-25
Publication date: 1934-08-21
Anticipated expiration: 1951-08-21

Description

Aug. 21, 1934; w, R LEAR 1,971,315

COUPLING DEVICE Filed June 25, 1931 3 Sheets-Sheet 1 [Tu/6222 07 z'czmPL ecu W. P. LEAR COUPLING DEVICE Aug. 21, 1934.

:5 Sheets-Sheet Filed June 25, 1931 ZMz'ZZz'am Fleur Aug. 21, 1934. w. P. LEAR 1,971,315

' COUPLING DEVICE Filed June 25, 1931 5 Sheets-Sheet I5 Q frzz/erzzf' William .PLear Patented Aug. 21, 1934 UNITED STATES 1.911.315 .conrunc. nnvlcs William P. Lear, Chicago, 111., assignor, by mesne assignments, to Meissner Manufacturing Company, Chicago, Ill.

Application June 25, 1931, Serial No. 546,815 3' Claims. (01. 175-356) My invention relates to an electrical coupling device for radio apparatus and more particularly to ,a coupling device for a tuned intermediate frequency amplifier as used in superheterodyne receivers.

The use of shielding containers for intermediate frequency transformers causes energy losses in'the circuit and reduces the impedance of the transformer coils. This is objectionable and re 1. quires that additional impedance be added to the coils and that the containers be made large to space them farther from the coils.

These difliculties are overcome in the present invention by so relating the axes of the coils to 5 each other as to permit them to be closely spaced and so positioning the axes of the coils with respect to the axes of the container as to reduce the losses in the container to a minimum thereby increasing the eflective impedance of the coils 0 and allowing them to be made of relatively smaller size.

An object of thetinvention is to provide a new i and improved coupling device.

A further object is to provide a coupling transformer in which the axes of the coils are so dis posed as to allow the coils to be in close spatial relation.

A further object is to provide a shielding container for the transformer causing low loss of energy from the transformer.

A further object is to provide a coupling transformer device for providing high amplification and selectivity.

Other objects and advantages will-appear as the description proceeds.

Referring to the drawings: Fig. 1 is a side elevation of a coupling device embodying my invention,

Fig. 2 is a view of the device shown in Fig. 1 rotated through an angle of 90 degrees,

Fig. 3 is a plan view of the device, Fig. 4 is a bottom view of the device, Fig. 5 is a schematic detail view of the condenser of said device, Fig. 6 is a side elevation of a modified form of the invention,

Fig. '"l is a detail view of a further modification,

3 is a fragmentary view showing a modification in the mounting of the device,

9 is a circuit diagram showing the device as connected in a radio circuit,

10 is a side elevation of a modified form of mounting for the'coupling device, K Fig. his a longitudinal section taken on line 11 of Fig. 10, and

Fig. 12 is a cross section taken on line 1212 of Fig. '10. Referring now more in detail to the drawings: a base 11 of any suitable insulating material is provided for supporting the coupling device. Extending upwardly from the base is a forked support 12 having a pair of parallel arms for supporting

coils

13 and 14. On either side of the support 12 and secured to the base is a; condenser 15 which has a straight side lying along the support and parallel therewith and a semi-circular side which conforms to the contour of the base. Each of these condensers, as may be more clearly seen in Fig. 5 consists of a condenser plate 16 secured to the base, a second condenser plate 17 separated from condenser plate 16 by a sheet of dielectric material 18 and a flexible condenser plate 19 separated from condenser plate 17 by. a sheet of dielectric material 21. The

plates

16 and 19 are interconnected by a tubular rivet 22 extending throughthe base and form in eflect a single plate of thecondenser. The capacity of this condenser may be varied by ad- Justing the position of plate 19 by means of a bolt 23 which extends through the base and has 30 a slotted head 24 underneath the base so that the capacity of the condenser may be changed from underneath the base. The plate 17 forming the second plate of the condenser has a downwardly projecting lug 25 for making electrical 8 contact with this plate of the condenser. Each of the condenser plates 1'1 also has an upstanding lug 26 to which the support 12 is attached.

The

coils

13 and 14 are wound on a cylindrical core 27 of wood or other suitable insulating material and each of these cores is provided on diagonally opposite edges with a slot or groove so that the core flts slidably between the arms of support 12. Both of the cores of the two coils are identical, but by reversing the cores they may be so placed between the arms ofthe support that the axes of the coils are not parallel. However, the axis of each coil is perpendicular to the arms of the support.

One of the chief difliculties encountered in obtaining the proper characteristics for the coils of an intermediate frequency transformer is to obtain a sufficiently high impedance of the coils. when the coils are wound one upon the other, the impedance of the coils cannot be increased beyond a given value because by adding additional turns the capacity between the coils is also increased, to ofiset the effect of additional turns. For this reason the coils are separately wound into an annulus having a large number of turns,

the cross-section or Litz wire. turns in the coils, cure be taken not to hove 1e coils preieruhly he 0 rectangular. lit cl found thut the results are obtuine the coils are wcuuicl oi stranded wire commonly mourn as Litzendrah' or 0n account of the large munher of the coils may be very closely placed, in some cases having their peripheries in contact. In adjusting the mutual inductance between the coils the lower coil i l is first placed between the arm. the support and secured in position by placii small amount oi-sealing war: between the o and the arms of the support. The upp i is then adjusted until the proper che of the transformer are obtained and ti then also secured to the urms oi the supp means oi? sealing won or other suitable between the core and the arms. liluch oi the leads from one or the transformer coils c nected in parallel to one oi the condensers shown in Fig. 9, and four terminal leads, fill, 31 and 32 are brought out through the base so that connection may be conveniently made to the coupling device constituted by the coils and the transformers. In order to mount the cou-- pling device on ,a flat surface such as the top of radio chassis, a pair of U shaped clamps 33: ere secured to the base and these clamps or feet are secured to a mounting surface by means of screws 34. In order to magnetically and electrostatically shield the coupling device, a metallic container 35 having an open end is placed over the coils and base, and secured to the feet 33 by means oi screws 36. On account of the circular outline formed by condensers 15 the maximum capacity" may be obtained for the condensers within the available space upon the base and within the container. It will be noted that the axes 01' the coils are perpendicular to the axis 01 the container. By this arrangement the open end or the can is placed in the path currents which tend to be set up in the can by the transformer coils so that a. minimum amount of energy will be wasted through eddy current losses in the container and consequently the effective Impedance 01' the coils for a glven size will be higher which is an impor-- tant feature.

Fig. d'shows a. modified form of the invention which is in principlesimilar to the form shown in Figs. l'to 5 except that the base 11' is inverted in the container and adjacent the closed end there- 01'. The container is provided with apertures 37 through which the adjusting screws 23' of the condensers may be reached to adjust the capacity thereof. This is in many cases the most convenient arrangement because when the coritainer'35' is mounted upon the chassis, it is frequently inconvenlent to reach the screws for adjusting the capacity of the transformers.

Fig. 'I shows a further modification in which a support 38 tor the coils is provided with

arms

39 and 41. The arm 41 is made wide enough so that a grid condenser 42, grid leak 43 may be mounted on the arm; This construction may be conveniently used in the coupling device preceding the detector stage and shortens the leads from. the

the screen grid type is shown having a primary ii of the transformer coils in its anode circuit. The coil. 14 is connected through leads 139 and ill to unother audion which may an amplifier detector audlon. The disposition and conthe inlotion oi the coils accordance "ion makes it possible to cl.

-.l inductance between peaking of the resonance l ntc invention employirul: u lurked or support or" bake-lite, hard. rubber or he inoldable material. Referring to is shown having a support 62 mounted thereon. This support consists of a pair of

arms

63 and 64. lilielower portion of the arms consists of a substuntially rectangular pillar 65 interconnected hy on it shaped connecting member 66. A flange ll'l eutendc upwardly from each of the pillars to the top or the arm. On the inside oi the arm are inwardly extending flanges 68 which are provided with a plurality of serrations which fit into the grooves in cores 69. In positioning the cores 69 of the coils between the arms the coils are pooltloncd as described in connection with Fig. 1 and a small quantity of sealing wax is then placed in the serrations to form a more effective support for the coils on the arms. Each 01' the pillars 65 is provided with an aperture '71 for securing the support to base 61 by means oi screws 72 which pass through the bosom other support into the threaded apertures in the pillars 65. In this manner the U shaped or forked support is securely mounted on the base. The support is further secured to the base by the upwardly extending projections '73 formed on the condenser mounted on the base as described in connection with Fig. 1. In order to secure the shielding container 74 in position over the transformer the U shaped support is provided with a plurality of threaded apertures 75 which receive screw! passing through the container to rigidly pofltion the container on the support. These apertures 75 are countersunk as shown and the countersunk portions may have pegs inserted therein for supporting a shielding can when a larger size shield is used than shown. The upper ends of the modification shown in Fig. 6. when the sup- 141 port is inverted in the container the apertures 77 serve in securing the support to a base which may be the top of a radio chassis or any other suitable base. Thls'iorm or support for the transformer coils forms a rugged and economical iii support and securely maintains all of the parts in their proper spatial relationship.

It will be understood that the nature and embodiment of the invention herein described and illustrated are merely convenient and useful forms of the invention and that many changes and modifications may be made therein without departing from the spirit and scope of the invention.

What I claim is new and desire to protect by Letters Patent of the United States is:--

l. A coupling device comprising a pair of loosely coupled annular coils, a pair of substantially parallel arms for supporting the coils therebetween, the axes of said coils being at an angle to the plane including said arms.

2. A coupling device comprising a base, a pair of substantially parallel arms mounted thereon, a pair of coils, each of said coils being wound on a cylindrical support, said supports having grooves for slidably engaging said arms, and means for retaining said supports in position on said arms.

3. A coupling device comprising a base, a pair oi substantially parallel arms mounted thereon, a pair of coils mounted therebetween, the axes oi said coils being perpendicular to said arms, and at an angle to each other, whereby the coupling between said coils is reduced to permit close spacing of the coils.

l. A coupling device comprising a base, arms extending perpendicularly from said base, a pair oi? coils supported by said arms having their axes perpendicular to said arms and a metallic container on said base enclosing said coils, the axis of said container being substantially perpendicular to the axis of said coils.

5. A coupling device comprising a base, a support extending upwardly therefrom, a pair of transformer coils mounted on said support, a. pair of U shaped feet attached to said base to secure the device to a flat surface and a metallic container enclosing said coils and secured to said feet.

6. A coupling device comprising a pair of annular coils wound of standard wire, means for mounting said coils including a pair of substanti'ally parallel arms, the axes of said coils-being perpendicular to said arms and non-parallel to each other. I 7. A coupling device comprising a pair of annular coils having their axes in parallel planes but relatively angularly disposed and with one coil positioned directly above the other so that the plane or the axis of one coil is above the plane of the axis of the other coil, and means for mounting the coils in said position.

8. A coupling device comprising a pair of annular coils having their axes in parallel planes but relatively angularly disposed and with one coil positioned directly above the other so that the plane of the axis of one coil is above the plane of the axis of the other coil and a tubular shielding container positioned over the coils, the axis of said container being at right angle to the common plane of the axes of the coils to reduce the energy loss in the container and increase the impedance of,tlie coils.

" WILLIAM P. LEAR.