US1760566A - Microtelephone - Google Patents

Description

y 7, 1930. J. SCHNEIDER ET AL 1,760,566

MICROTELEPHONE Filed Feb. 2, 1929 Patented May 27, 1930 UNITED STATES PATENT; OFFICE JOHANN' SCHNEIDER AND GEORG- HECKMANN OF. FRANKFORT-ON-THE-MAIN, GER- MANY, ASSIGNORS TO THE FIRM FU'LD & 00. TIELEPHON' UI \TD TELEGRAPHEN-' WERKE A. Ga, FRANKFORT-ON-THE-MAIN, GERMANY MICROTELEPHONE Application filed February 2, 1929, Serial No. 337,057, and in Germany February 3,1928.

The invention relates to micro-telephones,

particularly wherein the handle and the casing for the receiver and the microphone are in one piece, being pressed or produced by 6 squirting. The purpose of the invention is a simplification of the outer and inner construction of such. micro-telephones, and consequently, a cheapening of the manufacture and an improvement in the efliciency of the in- .strument.

Known micro-telephones have the disadvantage that the user can, at any time, and Without any special appliances, obtain access to the sensitive internal parts of the microphone and of the receiver. It is true that proposals are already known for preventing an unauthorized openlng of the mlcrophone or receiver casings, by making it only possible to open these casings by means of special tools. These known micro-telephones have, however, the disadvantage that complicated and encumbering appliances must be fitted within the casings and that, further, for the operation of the special appliances, openings must be provided in the casings which are unnecessary for the proper purposes of the microphone or of the receiver and which lead to a deterioration of the transmission of speech.

By this present invention these disadvantages of known appliances are avoided. This is obtained in such a way that the walls of the casings (which are provided at their outer edge with internal threads) for the receiver and microphone, (which'are formed in the known manner as self-contained units), protrude from the outer parts of the said units and that the cover parts of the casings are, by their side surfaces, perfectly screwed into the casings. In this connection the uter surfaces of the'cover parts are formed in such a manner that they do not offer any hold-to the hand. The openings provided in the cover parts for-the oscillations of the voice are, in this connection, formed in such a manner that a special tool can grip within them, so that an unauthorized openin of the casings by hand is impossible.

The invention is represented by way of ex- 50 ample in the drawing, the description of which will make it possible to recognize further characteristic features of the invention.

The handle '1 is pressed or produced by squirting as a whole, together with the casing 2 for the receiver unit 3 and the casing 4 for the microphone unit 5, for example from usulating material. The walls 6 and 7 reectively of the casings 2 and 4, are longer than the corresponding thickness of thereings in the casings for the tools, the openings 12 and 13 of the cover parts are formed in a special manner. Thus, the opening 12 of the cover part 10 for the receiver casing 2 is hexagonal so that a corresponding key can engage within the same and the speaking opening 13 of the cover part 11 for the microphone casing 4 consists of slots,-into which corresponding projecting parts of a tool can be inserted.

The walls 6 and 7 of the casings are towards their outer ends, set off in shoulders or steps. Against these shoulders flanges or collars 26, 14, respectively carried by the units 3 and 5 are applied, whilst the cover parts 10 and 11 are situated in front of the flanges or collars 26 and 14. The units 3 and 5 are thereby maintained in a definite position.

Behind the microphone unit 5, and on a further shoulder of the Wall 7 of the microphone casing 4, a plate 15 is supported, which bears contact springs 16 and 17 and terminals 18.

The contact springs 16 and 17 engage against the microphone unit 5 and constitute the electrical connection with the two poles of the microphone. The contact spring 16 is formed as a plate spring and bears against a contact pin 19 at the-centre of the microphone unit- 5, Whilst spring 17 is formed with a ring 20,

which is pressed, When screwing-in the cover part 11, between the flange or collar 14 of unit 5 and the corresponding shoulder of the wallof the casing 7. With the terminals 18 of plate 15 are connected, on the one hand,

the wires of the flexible cord 21 and, on the other hand, the conductor 22 leading to the receiver unit 3. These conductors 22 are conducted through a metallic tube 23 originally pressed into or formed by moulding in the handle 1, which tube is itself used as a conducting connection. For this purpose tube 23 at its oints of entrance into the casings 2 and 3 is provided with terminals 24 and 25, to which are fitted the corresponding wire connections. With this arrangement it is only necessary to provide a very small recess in the cross section of handle, so that the handle retains a sufficient strength.

Having fully described our invention, what we desire to claim and secure by Letters Patent is 1. A micro-telephone comprising a handle carrying at opposite ends integral casings open at the front and interiorly screw-threaded, receiver and microphone units housed within the respective casings so that the walls of the casings project outwards beyond the said units, and covers having their edges screw-threaded and completely screwed into the open fronts of thecasings so as to engage the interior threads thereof, said covers having their outer surfaces formed so that they cannot afford a grip for the hand.

2. A micro-telephonecomprising a handle carryingatoppositeendsintegralcasings open at the front and interiorly screw-threaded, receiver and microphone units housed within the respective casings so that the walls of the casings project outwards beyond the said units, and covers having their edges screw-threaded and completely screwed into the open fronts of the casings so as to engage the interior threads thereof, said covers aving their outer surfaces formed so that they cannot afford a grip for the hand, and having non-circular sound-oscillation apertures shaped so as to be adapted to be engaged by the insertion of a tool.

3. A micro-telephone comprising a handle carrying at opposite ends integral receiver and microphone casings open at the front and interiorly screw-threaded at the outer ends and having interior shoulders, receiver and microphone units housed within the respective casings and engaged with the interior shoulders so that the walls of the casings project outwards beyond the said units, and covers having theirouter edges screw-threaded and completely screwed into the threaded open fronts of the casings so as to retain the receiver and microphone units against their respective shoulders, said covers having their outer surfaces formed so that they cannot afford a grip for the hand. .7

4. A micro-telephone comprising a handle carrying,at opposite ends integral receiver and microphone casings open at the front and interiorly screw threaded at their outer ends,

a single interior shoulder on the receiver ;microphone units housed within the respective casings the receiver unit engaging the single interior shoulder of the receiver casing and the microphone unit engaging the outer shoulder of the microphone casing, so that the walls of the casings project outwards beyond the said units, covers having their outer edges screw-threaded and completely screwed into the threaded open fronts of the casings so as to retain the receiver and microphone units against their respective shoulders said covers having their outer surfaces formed so that they cannot afford a grip for the hand, and a plate supported against the inner shoulder of the microphone casing.

5. A micro-telephone comprising a handle carrying at opposite ends integral receiver and microphone casings open at the front and interiorly screw-threaded at their outer ends, a single interior shoulder on the receiver casing, two interior shoulders on the microphone casing one near the inner end and the'other towards the outer end, receiver and microphone units housed Within the respective casings the receiver unit engaging the single interior shoulder of the receiver casing and the microphone unit engaging the outer shoulder of the microphone casing, so that the walls of the casings project outwards beyond the said units, covers having their outer edges screw-threaded and completely screwed into the threaded open fronts of the casings so as to retain the receiver and microphone units against their respective shoulders said covers having they cannot afford a grip for the hand, and a plate supported against the inner shoulder of the microphone casing, said plate carrying contact springs engaging the poles of the microphone unit and terminals for the connection of the conductors leading to the microphone and receiver.

6.--A micro-telephone comprising a handle carrying at opposite ends integral receiver and microphone casings open at the front and interiorly screw-threaded at their outer ends, a single interior shoulder on the receiver casing, two. interior shoulders on the microphone casing one near the inner end and the other towards the outer end, receiver and microphone units housed within the respective casings the receiver unit engaging'the single interior shoulder of the receiver casing and the microphone unit engaging the outer shoulder of the microphone casing, so

that the 'walls of the casings project outwards beyond the said units, covers having their outer edges screw-threaded and completely screwed into the threaded open fronts of the casings so as to retaiii' the-receiver and mitheirouter surfaces formed so that crophone units against their respective shoulders said covers having their outer surfaces formed so that they cannot afford a grip for the hand, and a plate supported against the inner shoulder of the microphone casing, said plate carrying contact springs engaging the poles of the microphone unit and termi nals for the connection of the conductors leading to the microphone and receiver, the plate being held against its shoulder by the contact springs pressing against the microphone unit.

7. A micro-telephone comprising a handle carrying at opposite ends integral receiver and microphone casings open at the I front and interiorly screw-threaded at their outer ends, a single interior shoulder on the receiver casing, two interior shoulders on the microphone casing one near the inner end and the other towards the outer end, receiver and microphone units housed within the respective casings the receiver unit engaging the single interior shoulder of the receiver casing and themicrophone unit engaging the outer shoulder of the microphone casing, so that the walls of the casings project outwards beyond the said units, covers having their outer edges screw-threaded and completely screwed into the threaded open fronts of the casings so as to retain the receiver and microphone 3 units against their respective shoulders said covers having their outer surfaces formed so that they-cannot afl'ord a grip'for the hand, a plate supported against the inner shoulder oi the microphone casing, and a metallic tube moulded in the handle having terminals at opposite ends situated in the receiver and microphone casings respectively. a

In testimony whereoef we have aflixed our signatures. JOHANN SCHNEIDER.

GEORG HECKMANN.

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