US517763A - Stewart- d - Google Patents

Description

(No Model.

S. D. MOKBLVBY. MAGNETO TELEPHONE.

Patented Apr. 3, 1894.

1 4, abhor/wen IIIIIIIIIIIII HOGRAP'HING cOMPANY.

UNITED STATES PATENT OFFICE.

' STEWART. n'mexE vnv, OF CANTON, OHIO, ASSIGNOR OF ONE-THIRD To JOSEPH A. LINVILLE, OF SAME PLACE.

MA GNETO-TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 517,763, dated. April 3,1894. Application filed September 13,1893. Serial No. 485,430. (No model.)

To all whom it may concern.-

Be it known that I, STEWART D. MOKELVEY, a citizen of the United States, residing at Canton, in the county of Stark and State of Ohio, have invented new and useful Improvements in Receivers for Electric Telephones, Speaking-Telegraphs, Phonautographic Apparatus, and other Purposes, of which the following is a specification.

My invention relatesto receivers for electric telephones, speaking telegraphs, phonautographic apparatus, and-other purposes.

It is the object of my invention to provide a receiver which shall beof simple and economical construction, and to combine therewith. a bi-polar permanent magnet, having upon each of its opposite poles a steel core upon which is mounted a bobbin of fine wire connected in the secondary circuit, while the other bobbin is connected up in a tertiary circuit, whereby I am able to reproduce sounds of widely varying'intensity and increase the distinctness of all impulses transmitted. 7

It is my purpose, also, to provide a telephone rcceiver having an increased area of 1 vibratory diaphragm, so arranged in connection with an inclosed air-chamber as to set up a series of largely amplified vibrations which are concentrated upon the tympanum with largely reinforced effect. 7

It is'my further purpose to provide simple means whereby the receiving diaphragms shall have elastic support upon the wall of a circular air-chamber which has communication with the exit-opening of the receiver, whereby the pulsations set up in said chamber are reinforced upon opposite sides of the same, the phases of audible speech reproduced with increased accuracy and the in tensity of the sound waves multiplied.

My invention consists in the novel features of construction, and in the parts and new combination of parts hereinafter fully described and then particularly pointed out and defined in the claims.

To enable those skilled in the art to which my said invention pertains to understand and to make, construct or use the same, I will describe the invention in detail, reference being had to the accompanying drawings,in which- Figure 1 is aperspective view of a telephone receiver constructed in accordance with my invention. Fig. 2 is a central longitudinal section of the parts shown in Fig. 1. Fig. 3

is a similar section, the receiverbeing turned one fourth around, as compared with its position in Fig. 2. Fig. 4 is aview of one of the diaphragms of the receiver. Fig. 5 is a perspective view of'the cleft elastic ring which forms the wall of the air chamber. Fig. 6 is a. view 'of the second diaphragm, the parts shown in Figs. 4, 5 and 6 being separated, but shownin their proper position relatively to each other. Fig. 7 is a perspective viewof the polar extremities of the permanent magnet, showing the bobbins mounted upon their cores.

In the said drawings the reference numeral 1 indicates the shell, or casing of the receiver, provided with a handle 2, of any suitable form. The shell and handle are formed usually of hard rubber, though other suitable material may be employed. The shell is formed in two equal or similar parts in which is formed a chamber 3 communicating with a central channel, or exit-opening 4. In the ameter, its outer, cylindrical surface being threaded to enter a counterbored opening in the handle 2. The other end of the shell is provided with a screw cap 7 having a central orifice 8, which registers with the exit-opening 4. This screw-cap, in conjunction with the handle, holds the two parts composing the shell closely and firmly together. The interior of the handle is bored out to form a chamber 9, to contain part of the permanent magnet. The permanent magnet is formed of steel, the bar being bent at its middle point to bring the two legs 10 of said magnet into close proximity. .These legs have a slight divergence normally, and their extremities are bent outwardly, or away fromeach other, as shown in Figs. 3 and 7, and are then turned, into parallelism, or proximately so, forming polar extremities 12. Upon each of the latter is mounted a steel core 13, its end being seated in a vrecess in the inner face of the end 12, of the permanent magnet, and a'screw 14,

is passed through the latter and tapped into the core. Upon each core is mounted a bobbin, consisting of heads, or ends15, of insulating material, which are slipped upon the core, one resting against the inner face of the end 12 of the permanent magnet and the other being upon the unsupported extremity of the core 13. The bobbin is wound with fine wire 16, the terminals of which are brought out through apertures in. the other head 15, and connected in the manner hereinafter explained.

The construction of the parts described is such that when the cores are in place and the bobbins mounted thereon, there will be a space between the free, or unsupported ends .of said cores equal to, or somewhat greater than, the diameter of the exit-opening 4. In this intervening space is arranged an elastic ring, or rubber annulus 17, provided with an opening 18, which is formed by cutting away a small portion of said annulus. This opening is so placed as to be directly above the steel cores l3, and in avertical plane passing through their axis, as shown by dotted lines in Fig. 2. The rubber annulus 17 is of greater diameter, internally, than the diameter of the heads 15 of the bobbins, and between thelatter and said annulus are placed diaphragms 19, having such diameters that their peripheries are flush, or substantially so, with the exterior of the rubber annulus. By this arrangement and by the construction of the threaded ends of the two-part shell 1, the two diaphragms 19 are pressed by the parts of said shell closely against the annulus 17, thereby forming an air-chamber which is wholly inclosed save only the narrow exitopening 18. The cores 13 are thus so placed that their ends lie close to, but not in contact with, the outer faces of the diaphragms 19, and their position, relatively to said diaphragms, is adjusted by means of a loop 20, which is slipped over the legs of the permament magnet as shown in Fig. 3.

The permanent magnet with its attached parts is arranged within the shell 1 andbody 2 as shown in Figs. 2 and 3, the exit-opening 18 in the circular wall of the air-chamber inclosed by the rubber annulus 17, being located immediately beneath and in line with the exit-opening at and the orifice 8 in the screw cap. The terminals 21 of the fine wire 16, upon one of the bobbins, are connected with the secondary circuit and the terminals 22 of the other bobbin are, in a similar manner, connected with a tertiary, or third circuit. Any ordinary four-conductor cord 23 may be used for this purpose, and I have found it convenient to carry such a cord through the opening in the end of the handle 2, as shown in Fig. 3, and loop itaround the neutral portion of the permanent magnet, in order to prevent it from pulling out. It should be noted, however, that I may, without any change of construction, use one side, only, and in this event atwo conductor cord may be used.

In the construction of the ting or annulus 17, I prefer to use a rubber compound, having a degree of vulcanization which willpermit a considerable elasticity to remain in the ring, but I may use any other compound, or any material suitable for the purpose.

When the receiver is used with the Bell telephone, the fine wires 16 of the bobbins may be connected in series, a terminal of one being connected with the secondary of the induction coil and a terminal of the other with the main line. A like connection may be made upon one side of the permanent magnet, only, if this is desired. When made upon both sidesit is evident that the two diaphragms will act in unison and will respond equally to the same electric pulsations.

What I claim is- 1. A receiver for telegraphic, telephonic, phonautographic and other apparatus, having a shell formed in two equal and similar parts which are united by a screw-cap and a handle engaging with the ends of said shell, substantially as described.

2. A receiver for the uses set forth, having a shell formed in two parts which when united inclose a chamber adapted to receive the polar extremities of a permanent magnet, a screwcap turned upon one end of said shell and a handle having a threaded, counter-bored recess to receive a threaded neck on the other end of said shell, substantially as described.

3. The combination with a permanent magnet having bi-po1ar extremities brought opposite each other, of steel cores mounted upon the inner, or adjacent faces of said extremi suitable chamber provided with an exit-opem ing and a screw-cap having an orifice, of a permanent magnet having steel cores upon its two polar extremities, bobbins mounted 011 said cores, the terminals of one connected up with a secondary and the terminals of the other with a tertiary circuit, an elastic ring interposed between the ends of the steel cores and having a portion removed beneath the exit-opening of the shell, and diaphragms inserted between the ring and said cores, substantially as described.

5. The combination with apermanent magnet composed of a bar which is bent at its middle portion to form a two-part, divergent shank and bring its polar extremities opposite each other, of steel cores projecting from said extremities,bobbins mounted on said cores, an elastic ring interposed between the inner ends of said cores and having an opening, diaphragms inserted between the ring and cores, and a loop movable upon the two" part shank of the magnet, substantially as described.

6. The combination witha permanent magnot having bi-polar extremities brought opposite each other, of cores mounted upon the adjacent faces of said extremities, an elastic ring arranged between said cores and provided with an opening, diaphragms interposed between the opposite sides of said ring and the ends of said cores, and a two-part shell or casing, having an exit-opening and an orifice in its cap, arranged directly over and in line with the opening in the ring, the parts of said casing having bearing against the peripheries of the said diaphragms located therein to clamp said diaphragms against the elastic ring, substantially as described.

7. The combination with a permanent magnet having bi-polar extremitieswhich are nesses, I I

STEWART D. MOKELVEY. Witnesses:

JAMES L. NORRIS, THOS. A. GREEN.

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