IMPROVEMENTS IN PNEUMATIC AND ELECTRIC SIGNALLING OR COM- MUNICATING APPARATUS."
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by James Clark and Samuel Clark at
the Office of the Commissioners of Patents on the 4th December 1879.
"
JAMES CLARK and SAMUEL CLARK, of Glasgow, in the County of Lanark, North
Britain. IMPROVEMENTS IN PNEUMATIC AND ELECTRIC SIGNALLING OR COM-
MUNICATING APPARATUS."
This Invention has for its object to simplify and otherwise improve the con-
struction and action of pneumatic and electric signalling or communicating
apparatus.
In the improved pneumatic apparatus tubing of any suitable material and of
small size (inch bore being in many cases sufficient) is employed for transmitting
signals, the sending end being provided with a "push" to be moved by hand so as
to force air along the tubing, such push moving a piston or compressing or in-
denting a rubber ball, cup, or diaphragm. In some cases the push or signal sender
may be arranged to act by suction instead of by forcing air. At the receiving end
a cup or hemisphere of rubber is by preference employed, this cup being formed
with flanges, by means of which it is held; and it is covered by a cup or case of
brass or other suitable rigid material, the air forced along the tubing acting on the
rubber cup by entering between it and its case. A flat or other flexible diaphragm
or bellows may be used instead of the rubber cup.
In one pneumatic arrangement for acting directly on a bell, the receiving rubber
cup raises a toothed rack which gears with a pinion on the same arbor as a spur-
wheel, the arbor being in vertically elongated slot bearings. When the rack rises
it lifts up the pinion and spurwheel, so as to make the latter gear with a pinion
on an arbor, having on it a rotating striker which acts on the bell. The downward
return of the rack does not cause a continuation of the striking action, as the
piston and spurwheel then move down their bearing slots, so that the spurwheel
gets out of gear from the striker pinion.
A second arrangement comprises a single-stroke bell action, and in it the clapper
is carried by a spring blade which is pushed by a piece jointed to a stud or rod
fixed to the rubber receiving cup. The jointed piece escapes after moving a short
distance, so that the clapper springs back and at once strikes the bell whether the
sending push is immedietely released or not. A multiple arrangement is inex-
pensively formed in connection with a single bell by arranging several clappers

page_text: round the bell, each with its actunting details and pneumatic communicating tube.
The clappers serve as indicators by continuing to vibrate for a short time after
acting.
In a third arrangement the pneumatic communicating apparatus is combined
with an indicator, a rod attached to the rubber cup pushing out the indicator
which is a shutter or plate hinged at its lower part so that it falls over and shows
its inner side on which the number of a room or any other indication is marked.
An electric circuit wire is connected to the indicator hinge, and another wire is
connected to a stud against which the indicator falls, the indicator being metallic
or partly so. This action completes the circuit which causes the ringing of an
electric bell or any other action that can be effected by means of the electric circuit.
A bell thus rung will continue to ring until the indicator is turned up again. Any
convenient number of such pneumatically actuated indicators may be combined
with a single electric circuit.
In a fourth arrangement one or more pneumatically actuated indicators are
combined with a single pneumatically actuated bell. The indicator is arranged to
turn down by the action of the rubber cup and to remain down until replaced by
land. Two rubber cups are combined, the front or outer one having attached to it
the rod or piece for moving the indicator, and which prevents this outer cup from
getting completely in, so that in the normal position there is a little space between
it and the inner rubber cup. The case has connected to it a tube leading to a case
and rubber cup arranged for actuating a bell as in either the first or second
arrangement hereinbefore described, and if a number of indicators have one bell in
common branch tubes from them are connected to the same bell details. When
air is forced through any communicating tube to an indicator case, it enters
between the case and the inner rubber cup, and uncovering the inlet to the bell
branch tube causes the bell to sound. On the inner cup being thus forced out-
wards it simultaneously moves the outer cup, and also forces the air through an
outlet provided for the purpose from between the two cups which ultimately
become in close contact. Then on the pressure in the communicating tube being
relieved, the outer cup at once returns inwards as far as it can go, but the inner
cup does not close the inlet of the bell branch until enabled to do so by the
reentrance of air between the two cups, the time required for which depends on
the relative size of a small hole by which the air enters. In this way time is
given for excess of pressure in the bell tube and apparatus to return to the com-
municating tube from which it issued.
In a fifth arrangement which is principally electric, two wires instead of one
are wound on the bobbins of the electro magnets, and the ends of the wires are
connected so that opposite currents are transmitted respectively, accordingly as the
push or key at the sending end is moved, by which means opposite movements of
the indicators are obtained.
In a sixth arrangement, also principally electric, an indicator is turned down, or
an electric bell sounded, or both actions produced on the rupture of an electric
circuit; and the arrangement is advantageously applicable as a thief detector to be
connected to safes, doors, windows, and the like. In this arrangement a coil or
bobbin with a soft-iron core projects through an opening in the indicator board,
and a small indicator shutter or plate with an armature is hinged to the face of the
board, so as when turned up to strike the core. A current through the coil keeps
the shutter up, but on the circuit wire being ruptured the shutter falls. A very
small iron core is used so as to have very little residual magnetism, and it is partly
encased in brass to give it sufficient weight. The shutter falls against a stud and
thereby completes an electric circuit so as to ring a bell. The two-wire electro-
magnetic arrangement hereinbefore described may be combined with the parts
forming the sixth arrangements.
A seventh arrangement comprises pneumatic appliances hereinbefore described
combined with dials, which may have words marked on them, such as those used
with ship telegraphs. A handle on the transmitting dial turns a pinion gearing

page_text: with a toothed rack which acts on a rubber cup or diaphragm, so as to force air
along the communicating tube to the receiving end, where a similar cup or
diaphragm acts on a pointer moving over the indicating dial. A bell sounder, such
as is herein before described, is combined with the other details to attract the
attention of the person who has to attend to the signals or orders. An adjustable
connection is introduced between the receiving cup and indicating point to admit
of it, and the sending handle or point being set in exact correspondence with each
other.
The seventh arrangement may be modified by combining two communicating
tubes arranged to admit of the sending handle being turned in either direction;
and the handle may act through a spurwheel and pinion geared together, so that
the pinion makes several turns and imparts a distinct impulse to the air for cach
compartment of the dial. The apparatus inay also be arranged for the transmission
of replies either from the engineer or other person, or automatically from the
engines, either through the same or separate tubing.