IMPROVEMENTS IN CARRIAGES AND APPARATUS FOR DISAPPEARING GUNS
Year: 1877

page_text: LETTERS PATENT to Alexander Moncrieff, of No. 16, Cromwell Crescent, South
Kensington, in the County of Middlesex, for the Invention of "IMPROVEMENTS
IN CARRIAGES AND APPARATUS FOR DISAPPEARING GUNS."
PROVISIONAL SPECIFICATION left by the said Alexander Moncrieff at the
Office of the Commissioners of Patents on the 27th August 1877.
:
ALEXANDER MONCRIEFF, of No. 16, Cromwell Crescent, South Kensington, in the
County of Middlesex. " IMPROVEMENTS IN CARRIAGES AND APPARATUS FOR DISAP-
PEARING GUNS."
My Invention relates to guns of the kind known as disappearing or Moncrieff
guns, described in the Specifications of Patents previously granted to me.
I construct carriages for disappearing siege guns in the following manner :-Each
side of the carriage consists of a framing made in the form of an obtuse angled
triangle, with the obtuse angle downwards. The front acute angle has the axles of
the wheels affixed to it, the back acute angle rests on the ground or platform, and
at the obtuse angle is mounted by trunnions the oscillating hydraulic cylinder,
which communicates with the vessel containing compressed air for working the
disappearing gear of the gun on the hydro-pneumatic principle set forth in the
Specifications of my previous Patents. The ram or plunger of the hydraulic
cylinder, or a rod extended from it, is jointed by a forked head to the trunnions of
the gun, and these trunnions also work in bearings at the ends of radius rods, the
other ends of which are pivotted on the wheel axles or on points of the triangular
frames near the axles. Thus the trunnions of the gun, the lower pivots of the
radius rods, and the trunnions of the hydraulic cylinder constitute three centres,
round which the system works, raising the gun into firing position when the
hydraulic plunger is thrust outwards, and allowing the gun to move downwards
and backwards, in its recoil pushing the plunger inwards.

page_text: I prefer to arrange the radius rods above mentioned so that the trunnions of the
gun can slide upwards or downwards in slots in them, or that bearings for the
trunnions can slide on the rods. This arrangement is convenient for mounting
the gun, the trunnions being then in their lowest positions, and the gun being
mounted is raised by the action of the hydraulic plunger, whereupon the trunnions
are secured at the upper ends of the radius rods by suitable pins or keys.
Hitherto the elevation or depression of the gun has been determined by means of
thrust rods applied behind the trunnions, the weight preponderating at the breech.
In some cases I prefer to substitute jointed rods or chains applied in front of the
trunnions, and consequently subjected to tensile strain. When reflecting sights are
employed it is convenient to employ two mirrors, the one fixed on the face of the
trunnion, and the other on the radius rod or its pivot, and to make the former
adjustable, so as to determine thereby the elevation of the gun.
In order to retard gradually the recoil of a disappearing gun, and arrest it, I
make the discharge aperture of the hydraulic cylinder at some distance from the
bottom, so that the plunger passes this aperture as it approaches the extreme of its
in stroke.
I provide in the lower part of the plunger or cylinder tapering chaces, or I
slightly taper internally the lower end of the cylinder, so that when the plunger
has passed the discharge aperture there is a small and gradually decreasing passage
for water from under the plunger, and the resistance thus presented to the farther
descent of the plunger serves to retard and arrest it, and thereby to retard and
arrest the recoil of the gun as it approaches its back extreme. In like manner,
when the plunger is moving outwards, raising the gun to firing position, I retard and
arrest the movement near the end of the stroke by the automatic closing of the
valve, by which the water under pressure is admitted from the air vessel to the
cylinder. This I effect by linking the stem of the said valve to the gun radius rods
or plunger by a slotted connection or its equivalent, so that as these moving parts
approach the extreme of their stroke the valve is closed. The discharge aperture
of the cylinder is as usual fitted with a check valve. I arrange this aperture and
valve in such a position that they face the one trunnion of the cylinder, and I in
like manner arrange the valve for effecting the raising of the gun facing the other
trunnion, these parts being thereby rendered more secure and accessible for cleaning
and repair by the removal of covers or plugs fitted to the trunnions.
The discharge of the water from the hydraulic cylinder is preferably directed as a
jet, so as to cool the air under compression.
For disappearing guns, to be used on the decks of vessels, I employ an arrange-
ment of jointed framing similar to that described above for siege guns, that is to
say, radius rods supporting the trunnions of the gun along with the forked end of a
hydraulic plunger, the radius rods being in this case pivotted at their lower ends on
a revolving platform or turntable, and the hydraulic cylinder being mounted, not by
trunnions, but by a spherical pivot or gimbals on the deck below, so as to admit of
the oscillation of the cylinder in any plane, according as the turntable with the gun
is turned round to any desired attitude. The turntable is made with a slot to
admit of the traverse of the hydraulic plunger, and this slot is curved on the under
side, and a corresponding curved shield attached to the hydraulic cylinder is fitted
to it, so that whatever be the position of the cylinder the slot is always covered:
In cases where it is desired to raise the gun to firing position above a deck
higher than that on which the turntable is mounted, I provide in the higher deck
a second turntable firmly connected by framing to the lower turntable, so that both
turn together. Through this upper turntable I provide a slot of sufficient size for
the gun to rise and descend through it, and over the upper turntable I provide a
hood to cover the gun and the slot through which it works.
The duplicate turntable described above may be employed with disappearing
guns mounted in other ways, such as I have described in previous Specifications,
and when such duplicate turntable is employed I prefer to make the framing
A

page_text: which connects the two turntables together, as solid walls, forming between the
turnables a chamber enclosing the gun and its gear. The side walls of this
chamber are preferably made with guide arcs, along which the recoil rods or levers
are guided in their movements.
When a hood or cover is applied above the upper turntable, I provide on it sights
connected by rods with the elevating gear in the chamber below, so that any
elevating or depressing movement given to the gear is at once truly indicated by
the sight above.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Moncrieff in the Great Seal Patent Office on the 26th
February 1878.
ALEXANDER MONCRIEFF, of No. 16, Cromwell Crescent, South Kensington, in the
County of Middlesex. "IMPROVEMENTS IN CARRIAGES AND APPARATUS FOR DISAP-
PEARING GUNS"
"Moncrieff"
My Invention relates to guns of the kind known as disappearing or
guns, described in the Specifications of Patents previously granted to me.
I construct carriages for disappearing siege guns in the following manner-Each
side of the carriage consists of a framing made in the form of an obtuse angled
triangle, with the obtuse angle downwards. The front acute angle has the axles of
the wheels affixed to it, the back acute angle rests on the ground or platform, and
at the obtuse angle is mounted by trunnions the oscillating hydraulic cylinder,
which communicates with the vessel containing compressed air for working the
disappearing gear of the gun on the hydro-pneumatic principle set forth in the
Specifications of my previous Patents. The ram or plunger of the hydraulic
cylinder, or a rod extended from it, is jointed by a forked head to the trunnions of
the gun, and these trunnions also work in bearings at the ends of radius rods, the
other ends of which are pivotted on the wheel axles, or on points of the triangular
frames near the axles. Thus the trunnions of the gun, the lower pivots of the
radius rods, and the trunnions of the bydraulic cylinder constitute three centres,
round which the system works, raising the gun into firing position when the
hydraulic plunger is thrust outwards, and allowing the gun to move downwards
and backwards, in its recoil pushing the plunger inwards.
I prefer to arrange the radius rods above mentioned so that the trunnions of the
gun can slide upwards or downwards in slots in them, or that bearings for the
trunnions can slide on the rods. This arrangement convenient for mounting
the gun, the trunnions being then in their lowest positions, and the gun being
mounted is raised by the action of the hydraulic plunger, whereupon the trunnions
are secured at the upper ends of the radius rods by suitable pins or keys.
Hitherto the elevation or depression of the gun has been determined by means
of thrust rods applied behind the trunnions, the weight preponderating at the
breech.
In some cases I prefer to substitute jointed rods or chains applied in front of the

page_text: trunnions, and consequently subjected to tensile strain. When reflecting sights are
employed it is convenient to employ two mirrors, the one fixed on the face of the
trunnion, and the other on its radius rod or its pivot, and to make the former
adjustable, so as to determine thereby the elevation of the gun.
W
In order to retard gradually the recon
ince min. and arrest it, I
make the discharge aperture of the hydraulic cylinder at some distance from the
bottom, so that the plunger passes this aperture as it approaches the extreme of its
-instroke.
I provide in the lower part of the plunger or cylinder tapering chaces, or I
slightly taper internally the lower end of the cylinder, so that when the plunger
has passed the discharge aperture there is a small and gradually decreasing passage
for water from under the plunger, and the resistance thus presented to the farther
descent of the plunger serves to retard and arrest it, and thereby to retard and
arrest the recoil of the gun as it approaches its back extreme. In like manner,
when the plunger is moving outwards, raising the gun to firing position, I retard and
arrest the movement near the end of the stroke by the automatic closing of the
valve, by which the water under pressure is admitted from the air vessel to the
cylinder. This I effect by linking the stem of the said valve to the gun radius rods
or plunger by a slotted connection or its equivalent, so that as these moving parts
approach the extreme of their stroke the valve is closed. The discharge aperture
of the cylinder is as usual fitted with a check valve. I arrange this aperture and
valve in such a position that they face the one trunnion of the cylinder, and I in
like manner arrange the valve for effecting the raising of the gun facing the other
trunnion, these parts being thereby rendered more secure and accessible for cleaning
and repair by the removal of covers or plugs fitted to the trunnions.
The discharge of the water from the hydraulic cylinder is preferably directed as a
jet, so as to cool the air under compression.
!
For disappearing guns to be used on the decks of vessels I employ an arrrange-
ment of jointed framing similar to that described above for siege guns, that is to
say, radius rods supporting the trunnions of the gun along with a forked end of a
hydraulic plunger; the radius rods being in this case pivotted at their lower ends on
a revolving platform or turntable, and the hydraulic cylinder being mounted, not by
trunnions, but by a spherical pivot or gimbals on the deck below, so as to admit of
the oscillation of the cylinder in any plane, according as the turntable with the gun
is turned round to any desired attitude. The turntable is made with a slot to
admit of the traverse of the hydraulic plunger, and this slot is curved on the under
side, and a corresponding curved shield attached to the hydraulic cylinder is
fitted to it, so that whatever be the position of the cylinder the slot is always
covered.
In cases where it is desired to raise the gun to firing position above a deck higher
than that on which the turntable is mounted, I provide in the higher deck a second
turnable firmly connected by framing to the lower turntable, so that both turn
together. Through this upper turntable I provide a slot of sufficient size for the gun
to rise and descend throught it, and over the upper turntable I provide a hood to
cover the gun and the slot through which it works.
The duplicate turntable, described above, may be employed with disappearing
guns mounted in other ways, such as I bave described in previous Specifications,
and when such duplicate turntable is employed, I prefer to make the framing,
which connects the two turntables together, as solid walls, forming between the
turntables a chamber enclosing the gun and its gear. The side walls of this
chamber are preferably made with guide arcs, along which the recoil rods or levers
are guided in their movements.
When a hood or cover is applied above the upper turntable, I provide on it sights
connected by rods with the elevating gear in the chamber below, so that any
elevating or depressing movement given to the gear is at once truly indicated by
the sight above.

page_text: Fig. 1 represents a side view of a carriage according to my Invention for a hydro-
pneumatic disappearing gun; and Fig. 2 represents to an enlarged scale the
hydraulic cylinder and air vessel employed thereon.
The framing of the carriage consists of two side pieces A, each in the form of an
obtuse angled triangle, carrying at their front ends the axle B, and resting by their
back ends at C on the ground or platform. At the obtuse angles are mounted in
bearings the trunnions D of the oscillating hydraulic cylinder and air vessel E, the
ram of which, F, is connected by a forked cross head G to eyes, in which work the
trunnions H of the gun. These trunnions also enter slots of two radius rods I,
which at their lower ends have eyes working on the axles B, or it might be on
separate pivots near the axle, or on pivots on a block carriage where no axle and
wheels are used, or on a simple and rough timber frame.
The hydraulic cylinder and air vessel E are in one piece, the air vessel being of
annular forin, surrounding the cylinder. In the one trunnion is fitted the spring
outlet valve K, accessible by a hole fitted with a screw cover; the force of the spring
and the stroke of the valve are adjusted to suit the recoil. In the other trunnion
is fitted the screw inlet valve L worked by an external level . Thus the valves
are arranged inside the part strengthened and protected by the trunnions, by which
access is obtained to thein, and the trunnion being placed at some distance from the
bottom of the cylinder, the escape valve is in position for effecting the automatic
arresting of the recoil, as I will presently explain, thus dispensing with a throttle
valve.
Where it is inconvenient to place the trunnions and escape valve at the required
distance from the bottom of the cylinder, the passage leading to the escape valve is
so placed. The valve L has through it a passage for discharging the contents of the
air vessel, and the cover of the valve K has a passage for charging. In the lower
part of the cylinder there is formed a cavity or widening e facing the valve
apertures, and downwards from this cavity to the bottom of the cylinder the bore
is gradually diminished, or there are tapering chases f formed in the interior surface
of the bore. The air vessel being in its upper part charged with compressed air,
and in its lower part with water, or glycerine and water, when the gun is down in
the loading position, as shewn in Fig. 1, the lever is moved to a position, such as
is shewn at in the said Figure, thereby opening the valve L. Water under pressure
thereupon enters the cylinder, and presses the ram F upwards, raising the gun to
the firing position, the radius rods I turning on the axle B or their lower pivots, and
the cylinder and air vessel E oscillating on its trunnions. A stop or stud M being
adjusted on the framing in such a position that as the plunger F approaches the end
of its up stroke, the lever is by the oscillation of the cylinder brought to bear
against the said stop (which may be partly moved by the cylinder), the valve L
thereby becomes gradually closed, and the ascent of the plunger and gun is thus
automatically retarded and arrested. The valve L being closed, the gun is sustained..
in the firing position for such time as may be desired. On its being fired, the force
of the recoil acting on the plunger F forces it downwards, the water from its
cylinder escaping by the valve opening K into the air vessel by side apertures, so
arranged as to cause the water to rush in the form of jets or spray through the air
in the vessel for the purpose of cooling it. As the plunger approaches the end of its
down stroke, its end passes the hollow part e, and in descending along the tapered part
of the bore below or along the tapering chases formed therein, gradually reduces the
area for passage of water from below the plunger to the outlet valve, and thus the
descent of the plunger and of the gun in its recoil is automatically retarded and
arrested. It is obvious that for this purpose the plunger itself may be tapered or
have grooves formed on it.

page_text: The radius rods I are slotted for convenience in mounting and moving the gun,
that is to say, the gun may be mounted with the trunnions at any intermediate
position in the slots, and moved for the purpose of travelling with its trunnions
down at the lower ends of the slots in I, but on the ram F being raised by the
water pressure, the trunnions are raised to the upper ends of the slots in I, where
they are held in the firing position by the gibs and keys i¹.
The trunnions may obviously be secured in intermediate positions, and in such
cases, instead of employing slotted radius bars, I use preferably radius bars, on
which bearings for the trunnions are fitted to slide.
The elevation of the gun is determined in the usual way by means of the thrust
rods N raising its breech or allowing it to descend. Instead of these a tension rod or
chain may be attached to the gun in front of its trunnions, as indicated by the
dotted lines O.
For convenience of sighting I mount on one of the gun trunnions an inclined
mirror P, which can be set at the desired angle, and I fix another inclined mirror Q
on any convenient part of one of the radius rods I, so that objects presented in
front of the upper mirror can be seen reflected in the lower mirror.
Fig. 3 represents a side view of a hydro-pneumatic disappearing pivot gun,
according to my Invention, mounted for service on shipboard. In this case the
cylinder E is mounted on a spherical joint P, for which gimbals or a small turn-
table for the trunnions might be substituted. Q is the lower revolving platform,
having a slot in which the cylinder E can oscillate. The edges of this slot are
formed to a circular curvature on the under side, and a circular arc q attached to
the cylinder E moves along them, so as to shroud the cylinder below. R is
the upper turnable or revolving portion of the deck, which is firmly secured to the
lower turntable Q by two walls S, having between them space for the free movement
of the gun and its gear. On these walls I fix guide ares T, against which the
radius rods I bear, or in slots of which guide pieces attached to the radius rods
slide, so that the gun is thereby steadied in its movement.
Fig. 4 shews diagrammatically the connection of a sight above deck, with the
elevating gear below, for the purpose herein-before mentioned. T is a pivot on the
wall of the combing or hood X, corresponding with the axis of the gun's trunnion
when it is up in the firing position; and U is a sight bar mounted on this pivot,
the outer extremity corresponding with the pivot u of the elevating 10d.
V extends from this extremity to the joint W of the elevating slide below. Thus 3
the sight bar U corresponds in its attitude with the line of the gun when in its
firing position.
A rod
Having thus described the nature of my Invention and in what manner the same
is to be performed, I claim,-
First. Mounting a hydro-pneumatic disappearing gun by its trunnions on radius 4
rods pivotted below, and on the ram of the hydraulic cylinder, which is also
pivotted below, so that the whole of the disappearing action takes place on three
centres of motion, substantially as herein described.
Second. Mounting the gun trunnions in slots, or their equivalents, on the
radius rods referred to in the preceding claim, so that they can be slid along the 4
same, substantially as and for the purposes herein set forth.
Third. In the cylinder of a hydro-pneumatic disappearing gun arranging the
escape aperture at some distance from the end with restricted passages thereto,
whereby the fluid is throttled, so that the recoil is retarded and arrested,
substantially as herein described.
Fourth. In a hydro-pneumatic disappearing gun arranging the valves of the
hydraulic cylinder in the trunnions thereof, substantially as and for the purposes
herein set forth.
5
Fifth. In a hydro-pneumatic disappearing gun mounting the hydraulic cylinder
on a spherical joint or gimbals, so that it is free to revolve along with a turn- 5
table between guides, or in a slot, in which it is free to oscillate, substantially as
herein described.

page_text: Sixth. The use for sighting a disappearing gun when it is below deck, of a
sight bar above deck, connected to the elevating slide below, so that the gun
while in loading position can be laid to correspond, when it is run up, with the
sight thus taken, substantially as herein described.
In witness whereof, I, the said Alexander Moncrieff, have hereunto set my
hand and seal, this Twenty-fifth day of February, in the year of our Lord
One thousand eight hundred and seventy-eight.
A. MONCRIEFF. (L.S.)