US1641395A - Rectifying radio shield - Google Patents

Description

' Sept. s, 1927'.

1,641,395 T. MOORE RECTIFYING RADIO SHIELD Filed Sept. 15. 1924 ggmovvaw Patented Sept. 6, 1927.

UNITED STATES PATENT OFFICE.

[from moons. or cnvcrm'uri, onro.

nnorrrme nnmo SHIELD.

Application filed September 15, 1924. Serial No. 787,670.

In the building and operation of radio apparatus it has been found advantageous to.

provide metallic shields suitably grounded for collectin and removing stray currents which may e given off by various parts of the ap aratus and for neutralizing the so called ody capacity of the operator of the apparatus.

An ob'ect of my invention is to provlde a radio s ield which is simple and inexpensive to manufacture and which may be applied to various uses with a minimum of effort.

Another object is to rovide a shield of this character which wi l rectify stray currents and consequently cause them to be carried to a ground wire with greater rapidity than the present known metallicshields.

Another object of my invention is to provide a device of this kind which is flexible and has greater adaptability to its applica-' tion to radio apparatus. 7

These and other objects are attained by the means described herein and disclosed in the accompanying drawings, in which:

Fig. 1 is a fragmental plan view of a radio receiving apparatus having shields of my invention embodied therein.

- relative positions 0 Fig. 2 is a fragmental view of a shield of my invention showin diagrammatically the its component parts.'. The shield 3 comprises a base 4 which ma V be of any suitable material such as car board, fibre, fish pa r or the like, such base being preferably thln and flexible. The base 4 is itself a dielectric and has a dielectric boating 5 on its one side. The dielectric may be of any suitable material but is referably one which may be applied in solutlon such as shellac, water glass, or any suitable dielectric varnish. A conducting material 6 in a very.

thin sheet form is next placed over the dielectric subs'tance and is secured thereto by the natural adhesion of the dielectric solution. The conductormaterial 6 may be tin foil or similar material but is preferably 'formed of a foil composed of an alloy of one-half block tin and one-half lead. A la er of borax 7 or other suitable salts of li e chemical properties in the form of a solution is next applied over the conductor substance, water or alcohol or an other suitable fluid being used to keep t e borax in a solution form for'easily applying the same over the conductor. Next there 13 applied over the borax a quantity of aluminum 8 in thus eliminate vibration. Due to. the

sheet owdered or flour form. The material thus ormed is allowed to stand until the chemical action of the borax and metals has ceased after which the sheet is hardened and unified by means of heat and pressure ap-. plied in any suitable manner. The structure .thus formed is very flexible and tough but may be cut or drilled with an ordinary pocket knife and is thus very easily workedin applying it to its uses.

When it is desired to apply the rectifying shield 3 of my invention for example to the inside of the dielectric panel 9 of a radio receiving apparatus 10, a sheet of the shielding material is cut and erforated to accommodate the apparatus an instruments that may be applied to the panel by means of glue or shellac or in any other manner that may be chosen by the radio builder. The metallic side of the shield is electrically connected with the ground connection 11 offthe radio apparatus as is common in connecting the ordinary .electric shield.

WVhen' it is desired to place a shield between two instruments of a receiving set for example 13 and 14, the shield of my invention has been found to overcome one of the difiiculties previously experienced with plain metallic'shields. Two of the instruments 13 and 14 for example are giving ofi electrical energy or stray currents and are each mutually affected by said stray currents emanating from the other instrument. If a plain sheet metal shield is used,

these opposed. straycurrents set up vibratlons in the shield which are plainly audible 1n the radio reception. When it is desired to apply the shield of my invention to a ence of the fibre or card-board, any possible vibrations due to external disturbances will also be deadenedand rendered inaudible. It will be noted that there has been pro- ,vided a radio shield which is not only inexpensive of manufacture and ea to a l but which embodies the advantag z of a r e prestifier and thus produces results not attainable by the use of ordinary metallic shields.

What I claim is: 1. As a new article of manufacture a rectifying radio shield in the form of a single sheet.

2.- As a new article of manufacture a bi-' metallic radio shield in the form of a single sheet, the two metallic elements of the shield serving to recti alternating currents and -impulses transmitted thereto whereby 0g; posed stray. alternating impulses may carried away without disturbance.

3. Asa new article of manufacture a flexiv ble rectifying radio shield.- 1

- 4; In a device of the class-described the combination with a base of fibrous material a dielectric, a metallic conductor, a chemical salt and aluminum arranged one upon the having layers of tin foil, borax and aluminum respectively mounted thereon in the order named for forming a single flexible radio shield.

In testimony whereof, I have hereunto subscribed my name this 12th day of September, 1924;

TOM MOORE.

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