IMPROVEMENTS IN PNEUMATIC TUBES AND TUBE JOINTS
Year: 1879

page_text: LETTERS PATENT to Alexander Melville Clark, of Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
PNEUMATIC TUBES AND TUBE JOINTS." A communication from abroad by
Louis Adolphe Herrmann, of Paris, France.
Sealed the 22nd August 1879, and dated the 6th March 1879.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 6th March 1879.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN PNEUMATIC TUBES AND TUBE JOINTS." [A com-
munication from abroad by Louis Adolphe Herrmann, of Paris, France.]
.
This Invention relates to improvements in the tubes employed for the conveyance
of written messages by pneumatic agency. Wrought iron tubes are commonly used
for this purpose, coupled together by flanged joints, so as to be readily taken apart
for repairs, examination, or cleaning; but these tubes are expensive, and of limited
diameter. In order to meet the various requirements the tubes should be inexpen-
sive, of any diameter that may be required, be easily coupled together so as to make
a tight joint, and yet allow of the ready removal and refixing of a tube without any
skilled labour. To meet these requirements it is proposed to employ either cast or
wrought iron tubes (the former of which may be of any desired diameter) united by
an improved coupling joint secured without bolts or rivets.
The accompanying Drawing represents examples of the improved joint applied to
a cast and to a wrought iron tube. In Figure 1, a, a¹, aro cast iron tubes, which
may either be plain externally or have a slight shoulder b, b', near the ends, as
shown. In order to ensure the accurate connection of the tubes in the same axial
line the end portions as far as shoulders b, b', are turned in a lathe on the outside,
so as to be concentric with the bore of the tube.
In Figure 2,.c, c', are wrought iron tubes. These are plain externally. Both the
cast and wrought iron tubes are turned on the inside at the ends g, g, in order to
enlarge the bore slightly at the joints, which prevents any obstruction to the passage
of the pistons or carriers containing the dispatches through a want of uniformity in
the bore of the tubes. The tubes are coupled, and a tight joint is made by a thin
copper jacket or sleeve & fitting accurately on the end of the tubes, so as to slide

page_text: thereon. This sleeve is first slipped over the joint of the tubes, which it covers as
shown, after which it is encircled by a cast iron ring e, slightly conical internally,
and of sufficiently large diameter to leave an annular space between it and the tubes,
into which space lead f is run. The copper jacket & serves to hold the ends of the
tubes in the same axial line while the lead is being run in, and also prevents the
lead from entering at the joint.
The tubes are disconnected by knocking off the ring e by a blow in the direction
of the arrow, shown in each Figure, and then severing the annular lead packing f
There is thus no loss of material in unfastening this joint.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Great Seal Patent Office on the
28th August 1879.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent. “IMPROVEMENTS IN PNEUMATIC TUBES AND TUBE JOINTS." A com-
munication from abroad by Louis Adolphe Herrmann, of Paris, France.
This Invention relates to improvements in the tubes employed for the conveyance
of written messages by pneumatic agency.
Wrought iron tubes are commonly used for this purpose, coupled together by
flanged joints, so as to be readily taken apart for repairs, examination, or cleaning;
but these tubes are expensive, and can only be made of limited diameter. In order
to meet the various requirements the tubes should be inexpensive, capable of being
made of any diameter that may be required, be easily coupled together so as to make
a tight joint, and yet allow of the ready removal and refixing of a tube without the
aid of skilled labour. To comply with these conditions it is proposed to employ
either cast or wrought iron tubes (the former of which may be of any desired dia-
meter) united by an improved coupling joint secured without bolts or rivets.
The accompanying Drawing represents examples of the improved joint applied to
a cast and to a wrought iron tubo.
In Figure 1, a, a, are cast iron tubes, which may either be plain externally or
be formed with a slight shoulder b, b¹, near the ends, as shown. In order to ensure
the accurate connection of the tube in the same axial line the end portions as far as
shoulders b, b¹, are turned in a lathe on the outside, so as to be concentric with the
bore of the tube.
In Figure 2, c, cl, are wrought iron tubes. These are plain externally. Both the
cast and wrought iron tubes are turned on the inside at the ends g, g, in order to
enlarge the bore slightly at the joints, which prevents any obstruction to the passage
of the pistons or carriers containing the dispatches through a want of uniformity in
the bores of the tubes. The tubes are coupled, and a tight joint is made by a thin
copper jacket or sleeve d fitting accurately on the ends of the tubes, so as to slide
thereon. This sleeve is first slipped over the junction line of the tubes, which it

page_text: covers as shown, after which it is encircled by a cast iron ring e, slightly coned
internally, and of sufficiently large diameter to leave between it and the tubes an
annular space, into which lead is run. The copper jacket d serves to hold the
ends of the tubes in the same axial line while the lead is being run in, and also
prevents the lead from entering at the joint.
The tubes are disconnected by knocking off the cast iron ring & by a blow in the
direction of the arrow, shown in each Figure, and then severing the annular lead
packing f. There is thus no loss of material in unfastening this joint.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the herein-
before in part recited Letters Patent is,―
1st. Pneumatic tubes having the bore enlarged at the joints, as and for the pur-
pose specified.
2nd. A pipe joint composed of a closely fitting copper sleeve d and a cast iron
ring e coned internally with a lead packing run in between the two, substantially
as herein before shown and described.
In witness whereof I the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty seventh day of August, in the year of our
Lord One thousand eight hundred and seventy nine.