US1546470A - brown - Google Patents

Description

July 21, .1925.

s G. BROWN ELECTRICAL RELAY Filed Aug. 28,

1922 2 Sheets-Sheet 3.

"IVENn n July 21, 1925. 1,546,470

s. G. BROWN ELECIR 1 CAL RELAY Fild Aug. 28, 1922 2 Sheets-Sheet 2 mm a Patented July 21, 1925.

1,546,476 PATENT oFnicE.

SIDNEY GEORGE BROWN, F NOliTH ACTON, ENGLAND.

ELECTRICAL RELAY.

Application filed August 28, 1922. Serial No. 584,736.

To all whom it may conce n Be it known that I, Sirxnr Guonon BRowN, a subject of the King of Great lirit ain, residingat Victoria Road, North Acton, in the county of Middlesex, l'lngland, have invented certain new and useful Improvements in or Relating "to Electrical Relays, of which the following is a specification.

This invention relates to electrical relays adapted for use in the amplification of telephone-speech currents, of the type in which a microphone is operated by an armature in the form of a vibratory reed bridging the gap between the poles of a receiving polarized clcctromagnct.

According to this invention the reed operates the vibrating member of a differential microphone in the local or retransmitting circuit of the relay.

In a suitable construction embodying this invention a pair of receiving coils of hue wire are wound on laminated cores forming the pole pieces of a. horse shoe permanent magnet, the cores being directed towards each other, leaving a. gap across which extends the vibrating end or portion of a flat steel reed, the other end of which is firmly secured to a bascplate by two screws. 'lhe vibmling reed, at or towards its free end, carries the centre carbon or plate of the dill'ercntial microphone, preferably upon the end of a pin secured on the reed. v 'lhediametcr of the centre carbon is preferably about 0.35 inch. The microphone may be of the aperiodic ditl'ercntial type in accordance with the specification of my British Patent No. 120260.

Oscillations of the current set up variations in the magnetic field which cause the reed, together with the centre carbon of the microphone, to vibrate. 'lho microphone is connected to a. battery of. say 6 volts, the centre.- carbon, which is subjcct to vibration by the reed, being connected to theiiiiddlc point of the battery while. the outer carbons.

or plates are connected to the positive and negative terminals. Or'thc outer plates may be connected through the primary windings of two transformers to the same battery terminal, the opposite terminal being connectedto the central plate. I f a. transformer is used the receiving circuit for the relayed current is connected through the transformer secondaries.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be described more fully with reference to the accompanying drawings, inwhich:-

Figure 1 is a side elevation, Figure 2 an end elevation and Figure 3 a. plan of relay mechanism embodying this invention.

Figures 4 to 7 show details of the mechamsm; .i

Figure 8 is a. diagram of the electrical connections; and

Figures 9, 10 and 11 illustrate a. constructional modification of the device. 6

Figure 12 is a view, similar to Figure 5, showing a compound microphone.

A is the permanent magnet having pole pieces a on which the two receiving coils B are mounted. C is the vibrating reed. D

is the differential microphone. E is a support or standard carrying the magnet, reed, microphone and other members (if the mechanism and itself mounted upon a. base F., G is a cover titted over the device and attached to the base F.

In the construction illustratcdin' Figures 1 to 8 the magnet A is of the ordinary horse shoe shape, but the actual form is immaterial. The pole pieces a, which are preferably la'ninatcd, are secured by screws a" on the cornersof the magnet limbs,which are chamfcred so that the pole proach one another atabout .rig t angles, the adjacent ends being shaped so as to pro- .Vide a plane surface on each side of the narrow gap across which the reed 0 extends, the reed being parallel of the magnet.

The form of the reed preferred is showh in Figures 6 and 7, the part 0 being secured 88 pieces apto the longitudinal axis be adjusted to bring the pole pieces 0. ac-

curately into position relatively to the reed.

For this purpose the magnet is secured by the aid of the clamping plates H, II provided with clamping and securing screws r bolts. The forward plates II are secured by the screw bolts h on which are fitted the clamping nuts h, the bolts themselves being screwed into'the support E. The position of the forward endof the magnet is adjusted by these bolts and nuts while for fine adjustment of the magnet pole pieces relatively to the" reed one of the rear clamping plates H, which are clamped on the magnet near its bend by the screws h", receives the end of a set screw it which passes through ahole in the support E and'is adjusted from the other side of the support, a. strong spring h around the said set screw pressing the end of the magnet away from 'the support. A'slight turn of the screw it allows of very close adjustment of the pole pieces a relatively to the reed. -A- small collar 72. on the head of the set screw can be filed away at one side after adjustment and a -small screwed stud h provided on the support E to prevent accidental turning;

The microphone D comprises a solid block casing 11 secured on the support E by the "screw d and the pegs d. Themicrophone is preferably of the aperiodic differential t pe described in the specification of my ritish Patent No. 120260. and comprising a central carbon plate d lying in the granule filled cell d without attachment to any part of the microphone and supported entirely between the two granule layers and the side lining d, which may be of pile fabric such as velvet, allowing of free axial movement of the carbon plate without side displacement. The granules are packed on both sides of the centre plate at and between the.

outer plates d". r

The centre plate d: of the microphone is rigidly connected throughthe rod d to the tongue 0 on the end of the reed C so that any vibration ofthe reed due to the reception of telephone currents in the coils B is transmitted to the centre plate of the microphone, a movement in one direction causing increased compression in the granules at that side of the plate and a loosening of the granules at the other side so that the resistance is varied in opposite directions at the two sides of the microphone. The diameter of the centre plate (1 is preferably about 0.35 inch, but the precise dimensions would vary with the general size of the instru r ment and the work for which it is adapted.

It is necessary for the reed C to be pre vented from coming in contact with the poles a of the magnet as the reed might stick to the poles. At the same time the adjustment must be made so that the reed is as close as possible to the (poles .without actual ontact bein permitte at any time. To prevent'the risfi of contact a small ad justable stop is provided in the form of a screw J mounted on the magnet poles. The mounting may conveniently be arranged by fitting the screw sto J in the head j of the clamp screw j whic clamps the two small a little behind the front faces as shown in Figures land 2. By adjusting the screw stop J, the end of which lies just behind the tongue 0 of'the reed, the reed is prevented from accidentally meeting the faces of the pole pieces, but is allowed to approach them very closely so as to reduce the air gap to a minimum.

A suitable arrangement of circuit for the microphone relayis shown in Figure 8, which is a diagrammatic plan. The two coils B are connected to the terminals K, to which the receiving circuit is connected, while the centre plate (1 of the microphone is connected to one battery terminal L and the outer plates d are connected through the primary trans-former coils Z to the other "battery terminal L. This is given as an example of the differential microphone connections, but the invention is not confined to any special method of connecting up the microphone. The {coal or retransmitting relay circuit is connected to the terminals M to which the secondary coils m are connected as shown in the diagram. The form of microphone shown in Figure 12 is substantially the same as that illustrated in Figure 5, except that the' microphone is divided into two cells d, each of which has a central carbon plate 01- supported between the granule layers in the cells and lying within the side lining d; both the central plates (i being rigidly mounted on the rod (1. This compound micro hone is especially useful in connection wit a loud. speiaking telephone system.

In Figures 9, 10 and 11 a modified construction is shown of smaller size and more compact form, designed more especially for use as an amplifier in aural apparatus for the deaf, but adapted f 1' other purposes where an amplifier of em ll size is required. The principle of the modified device is identieal with that already described, but for convenience the device is circular and comprises a part circular magnet A mounted on the circular supporting baseE to which it is-secured by the screws a, which also serve to fix the pole pieces a, these pole pieces projecting transversely across the end of the magnet and approaching close to each other'at the centre to leave a small air gapbridged bgr the reed C which is secured at one end by the'scrmvc on the post 0 of the base E The po epieces a may be in the form of a single plate with a slot cut at the centre to form an air gap and leaving narrow bridging bars at each side,

To allow for fine adjustment-1' between the reed and the magnet poles the post a is made in a separate piece from the base E but is fixed by riveting in the base and can yield slightly in a resilient manner under the pressure of the small adjusting screw a secured in the base under the arm a of the post. By adjustment of this screw the angle of the post and the reed can be adjusted sufficiently to give the reqluired fine adjustment of the reed relative the pole pieces by the screw stop J corresponding to the screw stop J of the previously described construction, the screw stop being carried by the small 'bracket c' on the base E.

The microphone D is of similar type to that already described,but of much smaller and lighter construction and is mounted on the back of the base E which is recessed to receive the casing, the latter being screwed upon the supporting plate d of insulating material, the plate lying in a recess in the base E. The rod d connected to the centre plate of the microphone D is attached to the part c of the rated G and not to the tongue 0" as in the previous case. The microphone terminals are indicated at L corresponding to the terminals L of the vpreviously described construction.

What I claim and desire to secure by Letters Patent of the United States is :-5-

1. In an electrical relay, a receiving polarized electromagnet having closely approaching pole pieces, a vibratory armature reed bridging the ga between the lee, a differential microp mm in the loca or retransmitting circuit, means for connecting the vibratory member of said microphone to the said reed, and'means for effecting fine adjustments between the electromagnet and the reed.

2. In an electrical relay, a receiving polarized electromagnet having closely approaching pole pieces, a vibratory armature reed br dging the gap between the lee, a differential microp one in the locaor retransmitting circuit, a rod rigidly connecting the vibratory member of the microphone to said reed, and means for effecting fine adjustmzrits between the eiectromagnet and the re 3. In an electrical relay a receivinglpolarized electromagnet, thepoles of whic closely approach each other, a stationary support, a differential microphone, the casing of which is fixed on said support, a vibratory armature reed fixed at one end and bridging the gap of the magnet poles and connected rigidly to the vibratory member of the differential microphone, and a fine adjustment means for the. said electromagy to-the ma et poles.-. The reed is prevented from touc mg .ferential microp ones and and a fine ad ustment means between the said electrofnagnet and its support by means of which its poles can be adjusted closely to the reed.

I 5. In an electrical relay,'a(permanent ma net of horseshoe type provi ed with close y approaching le ieces, receiving coils mounted on 't e p0 e pieces, a stationary support for the magnet, a carrying member securing the magnet towards its pole end to the said support, a mounting for the rear end of the magnet provided with a screw adjustmentbetween the support and the magnet by which the position of the m net poles can be accurately adjusted by slight angular movement of the magnet, a stationary differential microphone, and a vibratory armature'reed fired towards its free end to the vibratory member ofthe differential microphone and secured to the stationary support at the other end.

6. In an electrical relay, a rmanent ma net of horseshoe type provi ed with close approaching ole ieces, receiving eoi s mounted on t e po e pieces, a 'stationary support for the magnet, acarrying member securing the magnet towards its pole end to the said support, a mounting for the rear end of the magnet provided. with a screw adjustment between the support and the magnet by which the position of the ma et polescan be accurately adjusted by slight angular movement of the magnet, a. stationary microphone, and a vibratory armature reed fixe towards its free end to the vibratory member of the microphone and secpred to the stationary support at the other en 0 i j 7. In an electrical relay areceiving polarized electroma pole pieces, avi ratory' armature reed ridgmg t e gap between the poles, a compound microphone com rising a pluralit of dif means or rigidly sccurin the central vibratory members of the sai microphones together and to the armature reed.

SIDNEY GEORGE BROWN.

t having closely ad acent

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