AN IMPROVED COMPRESSED AIR OR GAS SPRING AND STUFFING BOX TO BE USED IN CONNECTION THEREWITH
Year: 1875

page_text: LETTERS PATENT to Alexander Dick, of Cannon Street, in the City of
London, for the Invention of " AN IMPROVED COMPRESSED AIR OR GAS
SPRING AND STUFFING BOX TO BE USED IN CONNECTION THEREWITH.”—A
communication from abroad by Paul Giffard, residing at Paris, in
the Republic of France.
PROVISIONAL SPECIFICATION left by the said Alexander Dick at the
Office of the Commissioners of Patents, with his Petition, on the
6th January 1875.
I, ALEXANDER DICK, of Cannon Street, in the Oity of London, do
hereby declare the nature of the said Invention for "An IMPROVED
COMPRESSED AIR OR GAS SPRING AND STUFFING BOX TO BE USED IN CONNECTION
THELEWITH," being a communication to me from abroad by Paul Giffard,
residing at Paris, in the Republic of France, to be as follows:-
-
This Invention consists in the construction of an improved air or gas
spring and of a stuffing box to be used in connection therewith, and
whereby the piston or plunger employed is enabled to work in a per-
fectly air or gas tight manner.

page_text: A metallic air or gas tight reservoir is provided, into which is forced
and compressed air or gas, any suitable means or appliances being
employed for that purpose. In the centre of the cover of the reservoir
is an aperture in which is fixed the stuffing box. The latter consists of
a hollow ring (which may be grooved or corrugated) of hardened india-
rubber, the central portion of which has an inverted conical or funnel
shaped section, a space being formed between the exterior of such
inverted conical portion and the vertical exterior of the india-rubber
ring, which is tightly fitted into the before-mentioned aperture. The
lower edges of the inverted cone and of the vertical external portion of
the ring are respectively supported by a metallic ring or collar placed
beneath the same, and in which are formed holes or apertures, through
which the condensed air or gas is free to pass into the space exterior to
the inverted conical portion of the ring. The upper end of the piston or
plunger (which is of metal and of a cylindrical form) is arranged for the :
reception of the external weight or strain, the lower part being formed
so as to be capable of working through the before-mentioned stuffing
box up and down in the interior of the reservoir, and having a collar or
guide at the lower extremity thereof, which fits the interior of the
reservoir so as to enable the piston or plunger to work accurately. The
said collar or guide has holes or apertures for the air or gas to pass
through. The compressed air or gas passes upwards and exerts pressure
upon the exterior of the conical portion of the stuffing box, and thereby
forces the same against the exterior of the piston or plunger, thus
enabling it to work upwards and downwards in a perfectly air or gas:
tight manner. The descent of the piston or plunger by reason of the
weight or strain, which acts upon the upper part thereof, displaces and
necessarily further compresses the compressed air or gas in the reservoir.
By varying the shape of the latter the degree of offective resistance
or spring at any point of the stroke of the piston or plunger can be ;
accurately regulated. The pressure of the piston or plunger against the
stuffing box is always in direct ratio to the pressure in the reservoir, and
thus perfect air or gas tightness is always ensured.
The apparatus herein-before described, which admits of variation in
details without departing from the principles of this Invention, con- {
stitutes a steady effectual spring capable of being applied to a great
variety of purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said "Alexander Dick in the Great Seal Patent Office
on the 6th July 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
DICK, of Cannon Street, in the City of London, send greeting. .
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of January, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Alexander Dick, Her special
licence that I, the said Alexander Dick, my executors, administrators, and
assigns, or such others as I, the said Alexander Dick, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Ohannel Islands, and Isle of Man, an Invention for " AN IMPROVED
COMPRESSED AIR OR GAS SPRING AND STUPPING BOX TO BE USED IN CONNECTION
THEREWITH," a communication to me from abroad by Paul Giffard, residing
at Paris, in the Republic of France, upon the condition (amongst others)
that I, the said Alexander Dick, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Alexander Dick, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the annexed Drawings, and
to the figures and letters marked thereon, that is to say :—
The said Invention consists in the construction of apparatus con-
stituting an improved air or gas spring, and of a stuffing box to be used
in connection therewith, and wheroby the piston or plunger employed
is enabled to work in a perfectly air or gas tight manner.

page_text: A metallic air or gas tight reservoir is provided, into which is forced and
compressed air or gas, any suitable means or appliances, such as are well
known and understood, being employed for that purpose. In the centre
of the cover of the reservoir is an aperture in which is fixed the stuffing
box. The latter consists of a hollow ring (which may be grooved or
corrugated) of hardened india-rubber, the centre portion of which has an
inverted conical or funnel shaped section, a space being formed between
the exterior of such inverted conical or funnel shaped portion and the
vertical exterior of the india-rubber ring, which latter is tightly fitted
into the before-mentioned aperture in the cover of the reservoir. The lower
edges of the inverted cone and of the vertical external portion of the
ring are respectively supported by a metallic ring or collar, which is placed
beneath the same, and in which are formed holes or apertures through
which the condensed air or gas is free to pass into the space exterior to
the inverted conical portion of the ring. The upper end of the piston
or plunger, which is of metal and of a cylindrical form, is arranged for
the reception of the external strain or weight, the lower part being
formed so as to be capable of working through the before-mentioned
stuffing box in the interior of the reservoir, and having a collar or guide
at the lower extremity thereof, which fits the interior of the reservoir, so
as to enable the piston or plunger to work accurately. The said collar
or guide has holes or apertures for the air or gas to pass through. The
compressed air or gas passes upwards, and exerts pressure upon the
exterior of the conical portion of the stuffing, and thereby forces the
same against the exterior of the piston or plunger, thus enabling it to
work upwards and downwards in a perfectly air or gas tight manner.
The descent of the piston or plunger, by reason of the weight or strain
which acts upon the upper part thereof, displaces and necessarily further
compresses the compressed air or gas in the reservoir. By varying the
shape of the latter the degree of effective resistance or spring at any
point of the stroke of the piston or plunger can be accurately regulated.
The pressure of the piston or plunger against the stuffing box is always
in direct ratio to the pressure in the reservoir, and thus perfect air or gas
tightness is always ensured. The air is admitted to the reservoir through
a valve, which is placed in the bottom or any convenient part thereof, or
through the piston or plunger.

page_text: stitutes a steady effectual spring capable of being applied to a great
variety of purposes.
• I will now proceed to refer to the annexed Drawings, from which the
nature of the said Invention will more fully appear.
3 Figure 1 is a vertical section shewing the arrangements herein-before
described. A is the reservoir, which is formed of any suitable metal;
and B, the cover thereof attached by the screws O. This cover acts as a
support for the stuffing box, and as a guide to the piston or plunger D,
at the lower part of which is a metallic guide E of the same diameter as
O the interior of the cylinder of the reservoir. The guide is provided with
holes or apertures shewn at E' for the purpose of allowing the com-
pressed air enclosed in the reservoir to pass through. On the upper
part of the piston or plunger is a plate F for the reception of the
external strain or weight. H is the india-rubber stuffing; N is the
3 flange supporting the india-rubber stuffing, and N' are holes or aportures
therein to allow the air to pass through. The valve, by means of which
the air is admitted to the reservoir, is shewn at the bottom thereof.
P is a block of india-rubber enclosed in a metallic case P¹; I is a spiral
spring by which the block of india-rubber is restored to its normal
O position; S is the air hole by which the air is admitted; L is a plate
fixed by the screws L, and placed in the bottom of the reservoir above
the valve.
Figure 2 shews a somewhat different arrangement. B is the cover
and guide kept in position by the setting B'; O is the india-rubber of the
5 air hole of the valve; D is the valve plate. All the other letters refer
to the same parts, as indicated thereby in Figure 1.
It must be distinctly understood that although the valve for the
admission of air to the reservoir is shown in the annexed Drawings it is
not desired to claim hereby the construction or arrangement thereof
O separately and apart from the other portions of the apparatus.
Having thus declared and ascertained the nature of the said Invention
I would observe in conclusion that what are considered novel and
original, and which it is therefore desired to claim as constituting the
Invention secured by the said herein-before in part recited Letters
5 Patent are,-

page_text: whereby an air or gas spring is obtained, substantially as and for the
purposes herein-before described and set forth.
And, Secondly. The construction of an improved stuffing box, sub-
stantially as and for the purposes herein-before described and set
forth.
In witness whereof, I, the said Alexander Dick, have hereunto set
my hand and seal, this Fourth day of July, in the year of our
Lord One thousand eight hundred and seventy-five.