Switch.
1. (
Railway.) The movable rails which connect one line of rails with another.
Switches are known as
slub-switches and
split-switches.
In the
stub-switch the switch-rail has square butted ends, as at
A,
Fig. 6130 The switch-rails require to be moved in direct apposition, or a train running in direction
a b on rails
a a would run off the track, were the switch-rails
b b in connection with the siding, as shown.
In the
split-switch,
B C, the switch-rail is pointed, and somewhat automatic.
B shows it as applied to a main track and siding;
C, to three tracks, with either of which it may be made to coincide.
A train on either of the tracks
c c c will force over the switch, so as to run on to the main track
d. A train going in the direction
d c will run upon such one of the rails
c c c as may at the time be adjusted in connection by means of the switches.
A Y-switch consists of a simple divergent track, which does not again run into the main track.
Switches have been designed to be set in motion by the approaching engine, the object being to restore the main-line connection when a switch has been carelessly left open to a siding.
The idea has not been acceptable.
A portable switch is one which affords a temporary passage from one track to another, bridging the inside rails.
2. (
Telegraphy.) A device for connecting one circuit with another, or for dividing a circuit into
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two parts, or, in short, for altering any of the connections of a line or circuit.
The ordinary
ground or
lever switch is a small metallic strip pivoted at one end, the pivot being connected by a wire to one portion of an electrical circuit.
The other end of the strap can be turned to rest on an anvil or bed connected with the line desired to be brought into circuit.
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Railway-switches. |
The
plug-switch is one made of pieces of metal connected each to its appropriate wire or part of circuit, but slightly separated from each other, so that the insertion of a plug or pin in the interval between them connects them.
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Peg-switch. |
Fig. 6131 illustrates the
peg-switch.
a a′ are vertical notched bars, the first being connected with the line wire entering a station, and the second with the wire going out.
b b′, c c′ are metallic buttons to which are connected the instrument wires; all the buttons on the same horizontal line are connected together at the back of the switch.
The cut shows the circuit open.
To close it, with the office instrument in circuit, metal pegs are inserted in the orifices at
a b and
a′ c′, causing the current to flow through
a b to the instrument, and thence through
c a′ to the main line.
If desired to send through circuit without connecting the instrument, a peg is inserted only at
b′ a or
c′ a′. By a modification of the connections, this form is adapted for a terminal station.
By this means also any desired amount of battery power may be applied to one or more circuits by simply inserting metallic pegs in a graduated scale.
Every new position in which the peg is placed changes the number of cups brought into connection with that particular line.
The same apparatus is also arranged with spring catches, to enable the
chief operator to make a connecting loop with any line, or to join two or more lines together by inserting metallic clips connected with the loop lines into the catches.
Each line has two catches, and each will hold four clips, so that eight messages may be taken from one line at once.
By joining other circuits with these, a still larger number of copies may be made of any one message.
This system of switches enables the
chief operator to place himself in connection with any wire, and to study the work of the operator without his knowledge.
The apparatus is so simple and compact that the wires for several hundred lines may be brought within easy reach of one operator.
3. A key on a gas-burner to regulate the amount of gas passing, and, consequently, the light.
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Telegraphic switch-board. |
