US209115A - Improvement in switches for district-telephone systems - Google Patents

Description

3 Sheets-#Sheet 1 v T.4B. DOOLITTLE.. v Y Switch for District Telephone System. ANo. 209,115. v Y Patented Oct. 22, 1878.

3 l*Sheets-Sheet 2.

. T. B. DOOLITTLE.A

Switch for District Telephone System. No. 209,115. Patented Oct. 22,1878.

3l Sheets-Sheet 3. "Y

T. B. DOOLI'TTLB. Switch for District Telephone System.. No. 209,115. Patented Oct. `22,- 1878.

UNITED STATES PATE-NTOFFICE.l

THOMAS B. :oOoLI-TTLE, OF BRIDGEPORT, CONNECTICUT.

IMPROVMENT IN SWITCl-lES FOR DISTRICT-TELEPHONE SYSTEMS.

Speciiication forming part of Letters Patent No. 209,115, dated October 22, 1878; application filed April 10, 1878,.

To all/wm it may concern:

Be it known that I, THOMAS B. DO'OLITTLE, of Bridgeport, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in District-Telephone Systems; and l do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, makin g-a part of this speciication.

My invention relates to certain improvements in the art of transmitting sound and messages by the use of the telephone.

It has for its object to render sound or mes; sages sent through a wire between given points inaudible at any other than the initial and objective points; and consists not only of a general system, somewhat similarto the American District Telegraph, involving' a main ofce, wire circuits, battery, and a code of signals, but also of a novel instrument arranged in connection with the telephones along the line, whereby the telephones on any given circuit or circuits may bc switched together and messages transmitted between any two, all the balance being cut ont and prevented from taking up the message or conversation, as will be hereinafter more fully explained.

In the use of the telephone system as it exists at present, where more than two stations are connected with a line-wire, there is no practical means, that I am aware of, of preventing a message between any two stations from being heard or picked up at any or all ofthe other stations. This condition of things is a great disadvantage in the use of the telephone in a district system, where notice is sent to a main office to respond to an inquiry, or a command given to put two stations in communication.

My invention overcomes these disadvan-v ties so separated willv induce the third party to cease the use of his telephone, such cessation automatically re-establishing the conditions previously existing'.

To embody this system in practical form the following condition of things must exist:

There must be a central or main office, connected with the outlying stations by a circuit or circuits of wire. The circuit-wires entering the line, while at the same time the wire is cnt out behind any such station. This instrument will be described in detail presently.

In order that my general system and the novel devices employed may be fully understood, I will proceed to describe thesame, referring by letters to the accompanying drawings, in which- Figure l represents the arrangement ot wires and devices in the main office, including a novelswitch-board, an annunciator, system of bells, series of batteries, and one or more telephones. Fi g. 2 is view, partially in elevation and partly in section, of a novel instrument which I use at each station in connection with the telephones. Fig. 3 is a plan, illustrating the general system in operation and the results accomplished; and Fig. 4 is a plan view of the end of the instrument illustrated at Fig. 2, showing a detail of construction hereinafter referred to.

Vhere the same parts appear in the several gures they are designated by the same letters. I will rst in order refer particularly to Fig.

V1, in which 1 2 3 4, te., are a series of wires or lines entering the main oftice. These wires have connected with each a bell, A, and enter an annunciator, B, provided with drop-signs,

which are operated by the current passingthrough the wires or lines to which they are respectively connected from this annunciator B. The lines l 2 3, Ste., connect with a switchboard, C, to which are also attached one or more telephones.

D D, Sac., are vertical parallel metal bars, and E E, Sto., switch-cranks, by which the connections and changes inthe circuits are made.

F F represent two telephones, which, by reason of their connection with the switchboard, may be'put on any circuit or line. I preferably use two, in order that the use of any given circuit by subscribers may not prevent the receipt of signals or messages through any other independent line.

G G, &c., are a series of batteries, connected with the series of wires 1 2 3, &c., by any suitablemeans andH H, te., are aseries ot' pushbuttons,7 for giving signals to given stations by making and breaking the circuit.

I have shown the closed-circuit system, but, of course, do not conine myself in this respect. The metal bars and switch-cranks on the switchboard are, as before described, arranged parallel. The cranks are pivoted at their upper ends, the objects of this arrangement being that the attendant of the switch-board can, at

a glance, determine whether the circuits are in their normal condition or whether they have been changed, as the eye will readily detect any crank out of' a vertical line, and draw attenion to the fact that a circuit has been create The advantage of pivoting the cranks at their upper ends relative to their movement is that any tendency to gravitate, should they become loose, will not tend to accidentally establish an undesired circuit, which might be the case were the cranks pivoted below.

I will now proceed to `describe Fig. 2. I is a box or case, of any desirable form and material, upon which is arranged an alarm-bell, J, and armature K.

L is a bell-hammer, pivoted to the box or case, and operated by the current passing through the line-wire l.

F is a telephone, connected by wires to the posts M M on the case, c being a line and cl a ground wire.

N and N are two metal screw rods or bars, passing horizontally through the case in any convenient manner, and connected together by a wire, e, which vwire or another connects the rod N with the telephone line-wire post M.

O and Oare two more cross-rods, similar to those just described, and arranged below and parallel with the same; and P is a metal walking beam or bar, suitably notched, and resting horizontally upon the rods O O', in which position it is held against accidental displacement, and to which position it is antomatically returned, it' moved, by a spiral spring, Q, arranged as shown, one end to the bar P and the other connected to the case.

B. is a bow-spring, secured at the center to the bar P, and out of contact with the rods N `N' when in normal position. The object of this springis to keep bright and free from dirt the under sides of the rods N N and the top surface of the bar P, which is accomplished by the longitudinal movement of the ends of the spring when the bar P is vibrated, and the presence of any matter which might effect conductivity is avoided.

The line-wire l joins the bell-hammer post to the lower cross-rod, O, and the other end of the line-wire comes into the box from the opposite side and connects with the other lower cross-rod, 0', so that when the bar P is in its normal position on the rods O O it completes the line.

Instead of the two posts N N and wire e, I may, of course, use a single bar or plate.

From this construction and arrangement it will be seen that when the parts are in the position described the line-wire l is completed, or continued through the box or case by the bar P and its contact with the cross-rods O O', and that the telephone is in no manner connected with the line, but may be connected therewith in either direction by depressing one or the other end ofthe bar P, the ends of which project through the end of the box or case, and, when desired, may be so constructed that the bar cannot be weighted down, and thus guard against continued depression of the lever beyond the time absolutely necessary.

The result of depressing either end of the bar P will be manifest by observing the dotted lines, which show the bar with its left end depressed. 'Ihe right end has been elevated and has left contact with the. cross-rod O', and completely 4broken the connection with the line-wire to the right of the box as etectually as it' it had originallyte1minated at the box, while it has, by reason of coming in contact with the cross-bar N,.esta blished communication between the line-wire 1,\to the left'of the box, and the cross-bar N', which, through the medium of the wire e, cross-rod N, post M, and

wire c, has brought the telephone F onto the'm line. rIhe bow-spring R, it may here be remarked, not only subserves the ends before4 referred to, but also tends to maintain contact, which might otherwise be unintentionally broken by any slight tremulous movement of the end of the lever P.

When the end of the bar P is released, the spiral spring Q, returns the bar to its .normal position on the cross-bars O O' and cuts out the telephone F, so that all the telephones can only be put on the line by amechanical movement and operation. The end ot' the bar P must be kept depressed so long as the telcphone is in use; but to prevent it from being y so held beyond the time required by any forgetfulness, I propose to either curve the ends of the bar P, so that they cannot be weighted down, or when it is desiredto provide a special means to hold it down to free the hands, I employ such means as I have illustrated at Fig. 4 of the drawings, which consists of a hook,

f, upon which to hang the telephone when not in use, such hook being arranged under the end ot' bar P, so that when it is depressed and caught by a latch, g, the hook j' is covered or concealed, and it follows that before the telew W l-"W phone can be hung in place after use the latch g must be released, whereupon the spiral spring Q in the box immediately returns the bar P to its position, cutting out the telephone and re-establishing the main line. Were the bar P vibrated in the opposite direction to that shown in dotted lines at Fig. 2, the cross-rods 0 and N would be brought in connection, and, a priori, the line-wire l cut out from the left of the box or case.

Now, having described Figs. 1, 2, and 4, I will now, by reference to Fig. 3, illustrate how any station or subscriber can signal and communicate with the main office, and be put in connection or communication with any other station or subscriber on the same or any other circuit, and converse with said station without bein-g heard at any other point on the line.

Let S represent the main office, and suppose stations 2 3 4 5 are on a single limewire to the left of the ofiice, at each of which stations there are telephones, between which and the line-wire are arranged the devices shown at Fig. 2 of the drawings. In the iigure I am now referring to I have only shown so much of the device as is necessary to illustrate the operation of cutting in and out. Now, a person at station No. 5 desirin gto converse conlidentially with a party at station No. 3 first depresses the right-hand end ofbar P. This act produces a temporary break in the circuit and rings the alarm-bell at main oftlce, and drops the sign in the annunciator corresponding to the circuit sending the signal. The attendant immediately puts his telephone in circuit by means of theswitch, and person at station No. 5 informs him that he desires to speak with the party at station No. 3. The attendant then, by means ofthe push-button between the battery and such line, gives No. 3 the signal appropriated to. that station, and then by the telephone informs him that No. 5 wishes to talk to him. No.3 then depresses the left end of lever or bar P at his station, breaks the line between said station andmain office, and puts -ation No. 3 in telephonie communication with It will be observed that at all intermediate stations the telephones are normally out of thecircuit. When No. 5 and No.3 cease conversation the bars P are released, and vboth telephones are automatically cut out and the original circuit-line re-established.

If, during the time No.5 and No.3 are using the line, station No.2 should wish to converse with 4main oflice or any station on any other line-say, station No. 2 on line-wire No. 6-the main office would be notied, and by the observance of the steps just described No. 2 on linewire No. land No.2 online No.6 could converse at same time Nos. 3 and 5 were in communication. Now, suppose that while No. 5 and No. 3 are conversing No.4 should attempt to get in on the line, either for the purpose of calling main office or for picking up conversation 'between No. 5 and No. 3, the necessary movement of the lever-bar P to put him on the line with the office would only put him on line with No. 3, and at the same time cut out No. 5, which No. 3 would, of course, know 5 or, if No. 4 should reverse the movement of the bar P, he would be in communication with No. 5, and No. 3 cutv out, and the same result would ensue, and the moment he leaves his telephone the self-actin g bar P re-establishes the line between N o. 5 and No. 3.

Of course many changes may be made in the details of construction and arrangement of the devices employed without departing from the spirit of my invention; but

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

l. In a district-telephone system, a series of switches, normally constituting portions of the main line, and adapted to sever the main line and complete a circuit from the .earth at any station through either fragment of the brok'en main line on either side of said station, sub stantially as and for the purposes specified.

2. A district-telephone switch of conducting material, normally forming a portion of the main line and resting on two conductingposts of main line, and adapted to be swung about either of said posts, as centers, into contact with a metallic 'post having a groundconnection, substantially as hereinbefore set forth.

3. The case I, provided with an alarm-bell and armature, a vibratory bar, and four cross-rods and wire connections,substantially as and for the 'purposes set forth.

4. In combination with the vibratory bar P and the cross-bars N N', the bow-spring It, substantially as and for the purposes set forth.

5. The lever ends of the bar P, formed as described, in combination with the suspension-hook f and latch g, arranged to operate iff/wb

Images