US314946A - Mechanical telephone - Google Patents

Description

(No Model) 2 SheetsSheet 1.

I F. O. LUDLOW.

MECHANICAL TELEPHONE. No. 314,946. Patented Mar. 31, 1885.

2 gg 5 1m.

N0 Model.) 2 Sheets-Sheet 2.

F. G. LUDLOW.

MECHANICAL TELEPHONE.

No. 314,946. Patented Mar. 31, 1885.

WITNESSES INVENTOR a) MAM midi 1 4V" N. PETERS. Phnla-Lrlhegrnphcr. Washingou. D. c.

UNITED STATES PATENT OFFICE.

FREEMAN C. LUDLOIV, OF CINCINNATI, OHIO, ASSIGNOR TO-THE LUDLOIV TELEPHONE COMPANY, OF NEWPORT, KENTUCKY.

MECHANICAL TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 314,946, dated March 31, 1885.

Application filed June 10, 1884.

To aZZ whom it nuty concern:

Be it known that I, FREEMAN C. LUDLoW, a resident of Cincinnati, in the county of Hanr ilton and State of Ohio, have invented certain new and useful Improvements in Mechanical Telephones, of which the following is a specification.

The class of telephones to which my invention belongs acts upon the principle of the transmission of sound-vibrations through a tightly-stretched wire, the vibrations being transmitted to or initiated in the wire by a diaphragm at the speaking end, and received on a similar diaphragm at the other end.

I 5 The principal features of novelty in my invention are, first, a device for ringing a bell at the distant end of the line to call attention to the telephone; second, the device for connecting the tight wire to the diaphragm;

third, the device for holding the wire when the diaphragnrdoor is opened; and, fourth, a novel and useful construct-ion of the dia phragm itself.

The several features of my invention and the various advantages resulting from their use, conjointly or otherwise, will be apparent from the following description and claims.

In the accompanying drawings, Figure 1 is an elevation of a vertical central section from front to rear of a telephone illustrating my invention. Fig. 2 is a side elevation of the telephone, showing the bell. Fig. 3 is a front view of the telephone, the door being removed. Fig. 4 is a front view of the de- 3 5 vice, the door being present and closed. Fig. 5 represents a top view ofthe end of the wire and connecting parts. Fig. 6 shows the detail of the construction of the diaphragm.

Fig. 7 represents, in enlarged sectional side 40 elevation, the construction of the several parts, showing the levers E and I as when connected ready for signaling.

The telephone consists of a box or supporting-frame, A, closed by the door or frame B,

and which latter contains the diaphragm. The box A upholds and contains certain devices, to be more fully explained. From the top or upper portion of the box A is swung a yoke or piece, D. This yoke consists of two arms, (I d, and a center piece, (1 which (No model.)

has an opening, d, in the center, through which the wire passes, and is retained therein by the construction hereinafter described, and has a side piece, (1*, on each side of the opening (1, on which the wire catches.

To the lower arm, d, a bent lever, E, is pivoted. This bent lever E has two arms, one of which terminates at a short distance from the back of the box, and when the bifurcated lever I (hereinafter described) is pushed forward this lower arm impinges against the smooth surface of the back of said box or frame-work A, which latter serves as the fulcrum of the lever. The other end is provided with a head, a, and a notch, e, on 6 its under edge.

A strong spiral spring, G, is sprung between the arm d of yokeD and the back a of box A or equivalent support. This spring exerts its force in expansion, and hence tends to force 0 yoke D forward; but as the yoke D has the wire II passing through its center piece and retained therein, it serves, in connection with a similar device at the other end of the line,to keep the wire taut.

Also swinging from the top of box A is the bifurcated lever I. This lever consists of a handle, 1', and two arms, 1', which latter are swung from the top of the box A, while the former projects through the slot a in the bottom or lower portion of the box A. At the point of bifurcation the lever I is shaped to fit into the notch c, and thus permit the lever E to catch onto the lever I, as shown in Figs.

1 and 3. Two spiral springs, K, are strained between the lever I and the back a of the box, and tend to draw the lever backward.

The preferred means of connecting the springs K to the lever I is as follows: A vertical pin, m, is set in a projection, m, of the lever, and to the upper portion of this pin is connected the forward end of the spiral spring.

A similar construction obtains in connection with the other spiral spring K.

The door or diaphragm holder consists of a 5 frame, B, in which is an opening surrounded by a funnel-like projection, B, which serves to convey the sound-vibrations to the diaphragm C from the person speaking to said projection. This diaphragm C is immediately berco low this opening. The circular diaphragm C is set into the frame 13, and, as shown in Fig. 1, has only its periphery in contact with the frame, the frame being cut away or beveled fromthe periphery of the diaphragm toward the center, substantially as shown, and leaving the diaphragm entirely free to vibrate. The door B is hinged or otherwise detachably secured to the frame-work A, preferably at one side of the latter. \Vhen closed, the door does not come in direct contact with the edge of the box, but rests immediately upon rubber or other elastic blocks or pieces a". These elastic pieces prevent the vibrations imparted to the diaphragm from being dissipated by transmission to the box itself, and compel their complete or almost complete transmission to the wire. To further prevent loss of sound, as well as to avoid the introduction of extraneous vibrations, similar rubber or elastic buttons or pieces, a, are placed between the back a of the box and the wall or lintel TV, to which it is attached.

The wire H is provided with two hooks or projections, 71, which are part of the wire, and not merelyloosely attached to it. These hooks h loop over. or extend in front of the side pieces, at", as shown in Fig. 5. Forward of the hooks the wire H is bent slightly upward and terminates in an eye, if, which catches over the hook c, which latter is firmly attached to the center of the diaphragm G in any suitable manner. It is preferably connected to the diaphragm as follows: The shank of the hook is screw-threaded, and two washers, a n, are provided with female screws. One washer is placed on the front side and the other at the rear side of the diaphragm. The screw-shank of the hook is screwed through the rear washer and through the diaphragm, and the front washer screwed onto the said shank, thereby tightly holding the diaphragm between the washers, and securing'the hook to the diaphragm, and bracing the hook-shank so that it cannot tear out of or break the diaphragm, and also serves to better connect all vibrations of the diaphragm to the line-wire. The wire H passes baekwardly, escaping through the opening a in the box A, and proceeds through eyes or over pulleys or loops to another telephone of similar construction, and thus forms the line of communication between these two telephones.

, On each side and on top and bottom the edge of the box or frame-work adjacent to the door is cut away, and this opening, with the space between the door and box, conveniently makes the opening L, which exists on both sides of the telephone, and by giving free op ening to the air in the telephone-box prevents it interfering with the vibrations of the diaphragm O.

In one corner of the'box A a block orequivalent device, M, is placed.

the block M and the side of the box A is a wire, N, the inner end of which is so bent as to form two arms, a and a, the latter project- Passing through ing behind the arm (6, as shown in Fig. 3. To the outer end of the wire N the clapperwvire 0 is attached, and bent in such shape that the clapper o is brought into proper relations with the bell P. (Shown in Fig. 2.) A spiral spring, a", encircles the wire N, and when not compressed holds the clapper 0 in position. to receive the alarm from the individual from the other end of the line.

The peculiar construction of the diaphragm which I use requires special description. In Fig. 6 a cross section of the diaphragm is shown. dry wellseasoned wood, 0, bass or linn wood preferred. This wood is coated with (preferably thoroughly soaked in) shellac-varnish and allowed to dry. The shellac drying on the outer surfaces and there forming a coat I designate by the letter 0. (See Fig. 6.) I next give the front side a coat of shellac-varnish, and while the latter is tacky I prefcrabl y place thereon a piece of thin soft paper, 0, preferably glazed. shellac-varnish, and while the latter is still tacky applythereto a piece of thick paper, 0, preferably blottingpaper. This paper I then give a coat of shellac-varnish, and then apply another piece oflike paper, and I thus continue applying, alternately, acoat of varnish and a piece of paper till I have increased the thick ness of the diaphragm about one-sixteenth of an inch.

The main advantages of such a construction of the diaphragm are the following: The shellac-varnish toughcns the wood of the diaphragm and aids in preventing it from splitting. Thepaper also aidsin tougheningthe dia phragm, preventing it from splitting. The varnish or gum aids in rendering the diaphragm more resonant, and also renders the diaphragm impervious to the action of water or moisture in the air. Thus the diaphragm is at all times and seasons, and under all conditions, kept dry; and its functions are reliable and uniform, and it is always in condition to afford the best results.

"When desired, the number of layers of paper and gum on the front side of the diaphragm may be increased at pleasure; also, when desired, the number of layers of gum and paper on the back side may be varied or dispensed with at pleasure but when the wooden diaphragmic piece is thin, as is preferably the ease, layers of gum and paper are preferably present on one or both sides of the wooden diaphragmic piece. In certain in stances, however, where the diaphragmic wooden piece, after being coated on one or both sides, is of sufficient strength and reso* nance to be operative, the layers of paper and the extra layers of gum may be dispensed with.

This device of course requires a similar telephone at each end of the line, both connected with the wirein the manner heretofore de' scribed.

The method of operation is as follows: It

It consists of a plane or thin piece of I give the rear side a coat of first necessary to ring the bell of the other I telephone to call the attention of the individual at the other end. This is accomplished by pushing the lever I backward. At the same time, in order to prevent the bell of the telephone where the person is signaling from ringing while he is signaling, he presses on the button, compressing the spring, and moving the clapper toward the box A, and placing it in a vertical plane lying between the box and bell. By pushing the lever I backward the free end of the lever E is pushed or forced against the back part of the box, the lower arm of said lever being depressed by the continuance of the force on the lever I, and its upper end or arm being raised or elevated until the notch c is freed from contact or connection with the lever last named. This permits the spring G to come into play, and it throws the yoke D forward suddenly with some force, carrying with it the wire H. The wire II by this movement draws the cor responding yoke D in the other telephone at the other end of the line backwardly. The effect of this may be studied from Fig. 1. When the yoke D is forced backward, the arm d impinges against the arm a, and, through the intermediate mechanism, throws the clapper 0 rather smartly against the bell P. The springs K in the sending-telephone, assisted by the spring G in the receiving-telephone, immediately return the parts to their proper positions, withdrawing the clapper from the bell,and preventing it from dulling the sound of the hell by remainingin contact with it after setting it in vibration. The operator now releases his pressure on the button U, and the spring a expands and carries the clapper into position to receive the signal from the other end of the line and tap the adjacent bell. The attention of the person to whom the speaker wishes to talk having been ob tained, the conversation is directed against the diaphragm O, and as the two diaphragms are connected by a tight wire the vibrations are readily transmitted, and the individual, by placing his ear to the funnel B at the other end, can hear distinctly.

\Vhen it becomes necessary to open the door of the telephone, the handle 2' is drawn forward, carrying with it the yoke D. After moving forward a short distance, the sides d of the center of the yoke catch against the hooks h, and, drawing the wire forward, lift the eye h off of the hook c. The door can now be swung open, and the interior of the telephone be inspected. This method of keeping the door and diaphragm closed avoids the use of extra connections between the door and the box, and thus assists in keeping the vibrations in their proper sphere.

The simplicity of the construction and the perfection of its operation make this device one of the best extant.

Obviously, the eye h? may be substituted for the hook c on the diaphragm, and the hook a removed from the diaphragm and take the place of eye it in the line-wire, the position of the free end of the hook being reversed.

In the formation of the diaphragm, instead of shellac, sandarac or other soluble gum or gums may be substituted, and instead of the paper certain other fabrics or soft skins or other suitable substances may be used.

The various features of my invention are preferably employed together; but one or more of them may be employed without the remainder. One or more of the features of my invention may (so far as applicable) beemployed in connection with telephones or telephonic devices other than those herein specificall y set forth.

hat I claim as new, and desire to secure by Letters Patent, is

1. In a telephone, the yoke-piece D, consisting of arms (1 d, and provided with opening (1, and arm (Z being pivoted at or near its free end, spring G, operating against arm (I, and lever'E, pivoted to the free end of arm (1, and provided with a notch in its forward end, its rear end being the fulcrum, and the bifurcated lever pivoted at its upper ends, and having notch e, and handle, and springs K, substantially as and for the purposes specified.

2. In a telephone, the yoke-piece D, consisting of arms (Z d, and provided with open ing (1, and the arm (I being pivoted at or near its free end, spring G, operating against arm d, and lever E, pivoted to the free end of arm (2, and provided'with a notch in its for ward end, its rear end being the fulcrum, and the bifurcated lever pivoted at its upper ends, and having projection 19, and handle z, and springs K, and bell-crank lying across and in proximity to arm (1, to enable the latter to be operated by said arm, and clapper-shank O, clapper 0, and bell P, substantially as and for the purposes specified.

3. In a telephone, the yokepieee D, coir sisting of arms (I d, and provided with opening (1, and the arm (1 being pivoted at or near its free end, spring G, operating against arm (I, and lever E, pivoted to the free end of arm d, and provided with a notch in its forward end, its rear end being the fulcrum, and the bifurcated lever pivoted at its upper ends, and having projection p, and handle 2', and springs K, and bell-crank lying across and in proximity to arm (1, to enable the latter to be operated by said arm, and clapper-shank, clapper 0, bell I, knob U, and spring a, sub stantially as and for the purposes specified.

4. In a telephone, the yoke-piece D, consisting of arms (Z d, and provided with open ing (1, and the arm (I being pivoted at or near its free end, spring G, operating against arm (Z, and lever E, pivoted to the free end of arm (1, and provided with a notch, e, in its forward end, its rear end being the fulcrum, and the bifurcated lever pivoted at its upper ends, and having projection 19, and handle 2', and springs K, and line-wire having projections or hooks 71, substantially as and for the purposes specified.

5. In a telephone, the yoke-piece 1), consisting of arms (I d, and provided with opening (1, and the arm (I being pivoted at or near its free end, spring G, operating against arm d, and lever E, pivoted to the free end of arm d, and provided with a notch in its forward end, its rear end being the fulcrum, and the bifurcated lever pivoted at its upper ends, and having projection 19, and handle 7., and springs K, and line-wire having projections or hooks h and eye h and diaphragm provided with hook c, substantially as and for the purposes specified.

6. The yoke D, having arms (1 d and center opening, d spring G, operating against arm cl, whereby the yoke is held forward, and linewire having projections 71, for retaining it in connection with the yoke, whereby on suitable operation the signal is operated, lever I, spring or springs K, and the lever E, for connecting said lever I and yoke D, substantially as and for the purpose described.

7. The diaphragm 0, located in front of the box or casing, and provided with a hook, in combination with the line-wire formed at its end with an eye and projections h, yoke D, suspended by its upper arm, (I, provided with central opening, through which the wi re passes, and is retained when disconnection of the line with the diaphragm is made, lever I, and the intermediate lever connecting it with the lower arm of the yoke, spring G, and springs K K, all arranged to operate substantially as described.

8. In a telephone, the bell, clapper, clap- I per-rod provided with rod N, operated by suitable mechanism, the rod N arranged to slide horizontally, and the spring n for keeping the clapper in operating plane with the bell, and yet permitting the rod N, with clapper rod O and clapper, to be moved to one side, so that the clapper will be out of operating plane with the bell, substantially as and for the purposes specified.

9. The diaph agm consisting of a wooden piece impregnated with shellac, and at rear having alternate layers of varnish and paper, substantially as and for the purposes specified.

10. The diaphragm consisting of a wooden piece impregnated with shellac, and at rear having alternate layers of shellac and paper, and in front a layer of shellac and paper, sub stantially as and for the purposes specified.

11. The lever I, suspended at or near its top, and line-wire, projection h, and eye, and hook and diaphragm, and bell and clapper, the lever I being arranged in connection with yoke and its lever E, for enabling it when swung in one direction to connect or disconnect the line-wire and the diaphragm, and when moved in a contrary direction to ring the bell, substantially as and for the purposes specified.

12. The diaphragm consisting of a wooden strip having alternate layers of gum and paper, substantially as described.

FREEMAN O. LUDLOW'.

itnessesz .TNo. W. Srrznnm,

O. M. HILL.

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