Improvements in Sound Signalling and Speaking Tube Apparatus.
Year: 1891

page_text: of Application, 11th Apr., 1891-Accepted, 16th May, 1891
COMPLETE SPECIFICATION.
Improvements in Sound Signalling and Speaking Tube Apparatus.
I, JOHN WILLIAM BLACK of 71 Commerce Street Glasgow Plumber and
Gasfitter, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
My invention which relates to an improved sound signalling and speaking tube
apparatus is a further development of my prior Patent No. 6855 of 1884. The
present invention has for its object to effect certain improvements hereinafter
specified in both the sound signalling and the speaking tube parts of the apparatus.
A combined signalling & speaking tube apparatus as constructed in accordance
with my prior Patent consists of a mouth-piece attached by a collapsible chamber
to each end of the speaking tube and a bell or gong is fixed either upon or
sufficiently near to the speaking tube to be struck by means of a pneumatically
actuated striker contained in a branch of or from the said speaking tube. The
collapsible chamber, hereinbefore mentioned, being attached to a flexible tube, its
natural tendency is to hang vertically downwards, and in this position the mouth-
piece attached to it is closed by means of a ball or equivalent valve which rests
upon its scant.
When it is desired to ring the bell at the further end of the
speaking tube the collapsible vessel compressed by hand. When the signal is
made by compressing the collapsible vessel, the action of the moving air causes the
striker in the branch pipe further from the speaker to be suddenly raised up
therein and to strike the bell or gong at that end, thus producing an audible
signal which arouses the attention of the person with whom it is desired to com-
municate. Such person then, on taking hold of the mouth-piece at the further
end of the speaking tube and raising it to his ear, obtains, by virtue of the ball or
valve in each mouth-piece having fallen out of its seat, a free communication with
the person who has made the audible signal, as in the case of an ordinary speaking
tube.
The improvements constituting the present invention are hereinafter pointed out
in the claims.
And in order that my invention may be properly understood I have hereunto
appended two explanatory sheets of drawings whereon :-
Figs. 1 and 2 are, respectively, a side elevation and a front elevation of the
sound signalling and speaking tube apparatus with my improvements thereon.
Figs. 3 & 4 are views of the same, in respectively, part side elevation and
transverse vertical section and in part front elevation and vertical section.
Fig. 5 is a vertical section of an improved construction of collapsible chamber.
Fig. 6 is a vertical section showing a form of chamber with accessory parts for
sound signalling apparatus.
Fig. 7 shows in vertical section a slightly different form of chamber, having a
removable push knob.
Fig. 8 shows in part section, a signalling gong and chamber with accessory parts.
Fig. 9 is a part vertical section of an indicating arrangement.
Figs. 10 and 11 are sectional details.
On the drawings the same reference letters wherever repeated indicate similar
or like parts.
Referring to the speaking tube apparatus Figs. 1 to 4, a is the mouth-piece and
6 the collapsible chamber, attached to the flexible wire lined tube c at each end of
the speaking tube. The chamber which is of rubber is connected to the mouth-
piece a by the elongated extension d in which the ball e is placed. The extension
is narrowed at a', or has a rim or a ring in it, to serve as a seat for the ball e.. The

page_text: flexible tube c, is cemented or otherwise secured into the central channel f, cut in
the, preferably, wooden or metal socket w, which is secured to the wall or other
part by screws or otherwise, and upon which the bell or gong gis screwed. The
channel communicates by a pipe or tube f¹, indicated in dotted lines Figs. 1
and 2, with the bell or gong gin another compartiment or situation. In the
socket w is a branch or channel which may be of small diameter at its lower end
as shown at Fig. 3. In the upper enlarged part of this channel works a light.
preferably, metal striker or piston i, which, when the chamber bis collapsed or the
tube c is blown through, is, by the air pressure forced to fly upwards and strike the
bell or gong or g¹, as the case may be. The tube is preferably wire lined as
shown at and the lower end j' of the wire is bent across the tube to prevent the
balle passing up into or closing said tube. The tube e normally hangs vertically
downwards, as shown, so that the ball e rests on its seat and closes the mouth-
piece a. When the mouth-piece is raised to or near to the level of the speaker's
mouth the ball e, by gravity, runs down into the chamber and the passage of the
mouth-piece is thus cleared or opened.
C
Instead of having a ball valve as hereinbefore described a hinged valve e¹ such
as indicated at Fig. 4 may be used.
When there are a number or series of call bells or gongs arranged in a station,
kitchen, office, or other place I fit an indicator, preferably, upon the extension d of
the mouth-piece a and above the valve seat d. The indicator I prefer to employ
for this class of apparatus consists of a hollow tube or nipple & fitted into or made
in one piece with the extension d. In the nipple k a rod or piston is free to
slide.
The piston as shown in Fig. 3, has a shoulder on it to prevent it
coming out of the nipple which latter has also corresponding shoulders or stops k¹
and k². If the nipple k is screwed into the extension d the shoulder is preferably
formed by a ring inserted and fixed into the nipple but when the nipple is made
in one piece with the extension, the shoulder is preferably formed by a cap or
its equivalent.
In Fig 5 a collapsible chamber b is shown, which is made throughout of india-
rubber. In this case the wooden mouth-piece a and extension d as shown in
previous figures is dispensed with, the mouth-piece a being moulded in one piece
with the collapsible chamber b. m is a, preferably, vulcanite ring which is sprung
into place in the narrow neck of the chamber b. The ring m serves as a seat for
the ball e. An indicator k may be moulded with or fitted to the chamber
desired.
if so
When it is desired to provide a bell or gong simply for the purpose of calling
attention to any one part of a building or structure, and not for the purpose of
verbally communicating through a speaking tube, such for instance as street door
or kitchen bells, I construct such call bell in the manner represented at Fig. 6, of
the annexed drawings. This figure shows a push button o for a street door bell.
This push button communicates air pressure to a bell at any suitable part of a
house. The collapsible chamber is, as shown, preferably made somewhat in the
form of a hollow cone or a semi-sphere. The base of the cone or semi-sphere
may or may not be used as desired I prefer to have a base b', however, as it
prevents liability of air leakage around the rim (Fig. 8 shows a conic partly conic
or semi-spherical chamber without the base 6'). n is a metal guard corresponding
in shape to the chamber b. The press button o has a recessed and expanding or
trumpet shaped part o on to which the tapered open end or apex of the chamber b
fits tightly. The chamber has a hole in it which is pressed over the pipe o²
which latter communicates with the kitchen, calling station, or other part.
In Fig. 7 a collapsible chamber is shown made of rubber throughout, and
formed with a nipple o3 which is pushed over the end of the pipe o' thus making
a tight joint. The chamber is shown as fitted with a push knob made in two
parts 0, p. The ring shaped part p, fits into the opening at the apex of the
chamber and serves as a collar into which the narrow end of the knob o fits.
This arrangement forms a simple speaking and signalling apparatus. When it is

page_text: desired to speak through the tube o the knob o is
person may speak into the chamber and tube o².
into the collar p when the speaking has ceased.
have a gong or bell over it similar to Fig. 8.
merely pulled out so that the .
The knob o is pushed again
The chamber 6 will of course
Fig. 8 shows a cheap form of call bell for a signalling and speaking tube which
may be fitted, say at the kitchen end of the apparatus, instead of the form shown
at Figs. 1, to 4. The gong is forcibly struck by the hollow piston or striker i,
which is forced up the channel h by the sudden or jerked collapse of the conic or
other chamber at the opposite end of the apparatus. The metal guard n is fitted
inside the gong g. p is a screwed ferrule or ring for retaining the gong g in place.
The wood socket q is or may be secured by screws to the wall or other part. The
conic chamber is shown in this view without a base b', it being merely flanged
and pressed tight against the wood q. The button is similar in construction to
that at Fig. 7.
Fig. 9 shows an indicating apparatus for kitchen or other bells. The metal
socket is made with two channels h, h', and strikers i, i¹. The striker, is for
striking the gong or bell g (shown dotted) whilst the striker is for striking a
bent springs attached, at s¹, to the socket w. is a small screw, or there may be
a projection or stop provided in lieu of a screw, to prevent the striker striking the
bell g. The lower end of the spring has preferably a small disc t on it with the
number of the bell. The disc t is enclosed in a case with a glass front t.
When the bell is rung the striker causes the spring sto vibrate and thus
indicate to the attendant the bell that has been rung.
The pistons or strikers are in all cases preferably made as shown at Figs. 8
and 9 and in the detail view at Fig. 11 as the rim or flange u prevents dust
entering the channel h, and clogging the piston and also enables the channel /, to
be bored its full width throughout.
In cases where press buttons are used, should it be required to have an indicator
on the button such indicator is, preferably made as shown in Fig. 10. The press
button has a hole in it of a larger diameter at its inner end. In this hole or
channel is fitted a small bone or other indicator or piston which is partly
tapered, as shown, so as to prevent it being forced out of the button, or being
drawn back by the suction when blown out. The inner end of the channel vis
closed, as before, by a ring k². The press button o (Fig. 10) may have a tapered
end o on it with a groove p² so as to adapt it for insertion in or removal from the
opening in the apex of the chamber b when the tube o³ is used for speaking through.
The rubber of the chamber grips into the groove p² and thus retains the button o
in place. The form of button shown at Fig. 10, may be used in lieu of that
at Figs. 7 and 8; or the latter may have indicating pistons in them similar
to Fig. 10.
With the form of indicator shown at Figs. 1 and 3 when a signal is made it is
blown out but immediately the mouth-piece is lifted to reply it falls back into place
as it works casy in the nipple k.
With the form of hollow conic or nearly conic chamber shown at Figs. 6, 7
and 8 immediately the button o, is pressed, it collapses with a sudden jerk so as to
give a sudden movement to the air in the tube o². and cause the piston i to give a
decisive blow to the gong or bell at the other end. A spherical or like chamber
would not effect this sudden movement.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The collapsible rubber chamber b with mouth-piece made in one piece there-
with and having a ball or equivalent valve therein, substantially as herein before
described with reference to Fig. 5 of the drawings annexed.
2. In pneumatic signalling or speaking tube apparatus the hollow conical or

page_text: nearly conical collapsible rubber chamber (b) substantially as herein before described
with reference to Figs. 6, 7 and 8 of the annexed drawings.
3. In pneumatic signalling or speaking tube apparatus, a hollow conical, partly
conical, or semi-spherical collapsible rubber chamber having a button or equivalent
fitted or attached to the apex or top thereof, substantially as hereinbefore described
with reference to Figs. 6, 7 and 8 of the annexed drawings.
4. In pneumatic signalling or speaking tube apparatus a piston or striker (1)
having a rim or its equivalent thereon for the purpose of preventing dust getting
into and clogging the channel (4) in which said piston works, substantially as
hereinbefore described with reference to the annexed drawings.
5. The combination with a pneumatic signalling or speaking tube apparatus of
the class set forth, of a piston or indicator i fitted in a nipple k and operating,
substantially as hereinbefore set-forth.
6. A press button made in two parts, the part o fitting removably into the
part which latter is secured into the collapsible chamber substantially as and for
the purpose set forth.
7. In apparatus of the class set forth a press button o made hollow and having
an indicator (1) working therein substantially as hereinbefore set forth with
reference to Fig. 10 of the drawings annexed.
8. In apparatus of the class set forth, a mouth-piece a made with a hollow
extension, having a seat d', and in which works a ball valve (e) substantially as
hereinbefore described.
9. The combination with apparatus of the class set forth of a vibrating indicator
arrangement, substantially as hercinbefore described with reference to Fig. 9 of the
annexed drawings.
Dated this 10th day of Anvil 1801
H. D. FITZPATRICK,
Glasgow and London, Agent.