US1651922A - Shield for use with electrical appliances - Google Patents

Description

B. HUGHES SHIELD FOR USE WITH ELECTRICAL APPLIANCES Dec. s, 19.27'.r

Filed sep't. 18, 1925 #l F1012 I :fumo

ITITTITT man INV ENToR Bava/:MIM HUGHES ,my ATTQRNEYS Patented De'c. 6, 1927.

UNITED STATES BENJAMIN HUGHES, 0F MONTREAL, QUEBEC, CANADA.

SHIELD FOR USE WITH ELECTRICAL APPLIANCES.

Application led September 18, 1925. Serial No. 57,246.

This invention relates to new and useful improvements in shields or barriers for use with transformers and othenelectrical appliances and the object of the invention is to provide a shield which will prevent or stop with `the minimum amount of loss the magnetic, the static, or the electrofmagnetic influence` lield, or wave which may be thrown out from an inductance coil, a condenser, or any electro-statically or electro-magnetically charged body, from travelling over to another similar piece of apparatus and inducing a potential in that part.

Another object is to provide a shield of the class stated which will coniine the field of an electro-static, or electro-magnetic device and isolate it so that the approach of an object of electric or magnetic material will not interfere with the magnetic balance or tune of such devices.

A further object is to provide a shield of the class stated which will prevent unneces sary losses within the shield itself.

In my invention, I provide a shield which is composed of electro-magnetic conducting material in combination with insulating material or matter. This shield is placed in close proximity to or between any electrostatically or electro-magnetically charged body or bodies to form a barrier or wall across the path of travel of the electro-magnetic field, to cut oli or interrupt the mag* netic lines of force which would otherwise progress to regions Where other parts may be disturbed electrically by potential or currents being induced or influenced by such lines of force. p

In the drawings which. disclose many forms of my improved shield and the application thereof;

Figure 1 is a perspective view of a transformer with my improved shield forming part of the casing therefor.

Figure 2 shows the application of my im proved shield in mounting inductance coils for radio apparatus.

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Figure 3 is an elevation of a shield with conductors of square cross section embedded therein. v

Figure 1is a sectional elevation taken on the line 4 4 Figure 3.

Figure 5 is an elevation of a shield withl conductors of round cross section embedded therein.

Figure 6 is an elevation-similar teV lFigure 3, with conductors of oval cross section embedded therein.

Figure 7 is an elevation of a shield with strips of conducting material embedded in insulating material.

Figure 8 is a sectional elevation taken on theline 8 8 Figure 7.

Figure 9 is a shield made in the form of a comb.

Figure 10 is a sectional elevation taken on the line 10410 Figure 9.

Figure 11 is an elevation of a shield of slotted construction.

Figure 12 is a sectional elevation taken on the line 12-12 Figure 11.

Figure 13 is an elevation of a shield provided with a plurality of rows of conducting material embedded in insulating material.

Figure 14 is a sectional elevation taken on the line lil-14 Figure 13.

Referring more particularly to the drawings. and in particular to Figures 3 to 8 inclusive, 2() designates a piece of flat insulating material having embedded or moulded therein a plurality of metal conductors of various shapes, spaced from one another by the insulation. In Figure 3 the conductors 21 are made square and are preferably made of thin material. In Figure 5 the conductors 22 are made circular, while in Figures 6 and 7 the conductors 23 and 24 are made from small oval pieces and long narrow strips of conducting material respectively. In Figure 9 the shield is formed of a sheet 25, of conducting material having a plurality of open ended slots 26 formed `therein which form a comb-like structure. In Figure 11 the shield is shown constructed of a sheet 27 of conducting material having a series of parallel slots 28 formed therein. In Figure 13 a plurality of rows of dlscs 29, of any desired shape and 'in layers spaced from one another maybe embedded ormoulded in a sheet 30 of insulating material. Other modilications may be made in the construction, such as embedding particles of dust of an electrical conductive nature in a body of insulating material without departing from the spirit of the invention. The shield material may be made in long strips and out to suit the requirements of the user.

In Figure 1 atransformer 31 is shown, provided with a shield 32 constructed 1n a similar manner to the construction shown in Figure 10. The shield is placed asshown,

that is, at right angles to the magnetic lines of force emanating by inductance from the transformer and shown by the arrows 33. In Figure 2, the shield 34, is placed between the inductance coils 35 and which may be mounted in any desired manner on a panel 36. It will be readily understood that the uses of such a shield are many and varied as the device may be used as an enclosure for certain electrical equipment, or panels for radio devices, as part of a tuning condenser or to form a wall, partition or barrier placed in any position to prevent interference between any electro-statically or electro-magnetically charged bodies, devices, material or matter.

ln operation a shield of the class described when placed in the form of a sheet or a wall across the path of travel of an electro-magnetic field will act in a three-fold manner. l. The magneticallyv conductive particles which may be made of iron, nickel, cobalt, or any alloys containing such metals or materials will by reason of their magnetic propf erties conduct the magnetic component o the field along through themselves and send it back by a shorter and easier path to the source, thereby interrupting or cutting off the magnetic lines of force and preventing same from travelling past the shield.

2. The electro-static component of the vfield will be conducted to the immediate region surrounding each of the conductive particles because of their electric conductive nature and will be so distributed between the. conductive and non-conductive matter of the shield that the potential of the eld will be confined to the shield and may, if desired, be brought to earth potential by connecting a conductive piece of material from the conductive portions of the shield to earth as shown in Figures 9 and 11, so that an electro-magnetic field or wave interrupted by a wall or shield of this nature, will be divided into its component parts and brought under control, and may be carried off or dispersed as desired, instead of progressing to regions where other parts may be disturbed electrically by potentlal or currents induced in such parts.

3. The third advantage of using such an arrangement of material in shield construction is of great importance, that is the prevention of unnecessary losses within the `shield itself. This losstakes place in the form of eddy currents. When a continuous.

body of metal is used to interrupt an electro-magnetic lield of varying intensity, eddy currents .submerged within the metal will be set up and the path of such currents will tend to be at right angles to the lines of magnetic force. These eddy currents absorb energy and result in a definite loss, whereas a shield as herein described and which is made up of alternate conductive and nonconductive substances or matter acts as a barrier to the progress of an electro-magnetic field and at the same time prevents the llow of such eddyor loss currents within the body, by reason of the discontinuity of the conducting material through which the eddy currents flow, thereby dispersing the field at a minimum loss.

Having thus described my invention, what l claim is l. A. shield of the character described comprising a series of fiat metal elements embedded in a mass of insulating material,- the elements of said series being contained in a common plane in edge to edge relation with each element completely enveloped and isolated from the remaining elements by surrounding portions of the insulating material. y

2. A shield of the character described comprising spaced parallel series of flat metal elements imbedded in a mass of insulating material with the elements of each ser1es contained in a common plane in edge to edge relation, each of said elements being completely enveloped and isolated from the remaining elements by surrounding portions of the insulating material.

3. A shield as recited in claim 2 in which the elements of one series are staggered with respect to the elements of the adjacent scr1es.

ln witness whereof, I have hereunto set my hand..

BENJAMIN HUGHES.

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