Improvements in the Construction of Mortar Carriages.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in the Construction of Mortar Carriages.
I, CHARLES EATON CREECY, of Corcoran Building, Washington, District of
Columbia, United States of America, Attorney-at-Law, 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 :-
This invention relates to mortar carriages.
The object of the invention is to produce a mortar carriage of great efficiency as
a military arm both offensive and defensive, furthermore to effect an easy and
rapid manoeuvring of the gun, furthermore to obviate all lateral strains arising
from the recoil of the gun by a system of pneumatic recoil-cylinders arranged in
such manner that the resistance offered in taking up the recoil is always parallel to
the longitudinal axis of the gun at all angles of fire, furthermore to produce a con-
struction whereby the gun is returned to battery by the same system that takes up
the recoil one system acting in both operations without assistance of auxiliary
cylinders and springs as now in use and finally the object is greatly to simplify the
construction thereby reducing the liability of derangement of parts and reducing
the cost of manufacturing.
In the accompanying drawings;-
Fig. 1 is a side elevation partly in section of the gun and mount showing the
mortar at sixty-five degrees (65°) as indicated by the index also showing in dotted
lines the mortar in its recoil and loading positions.
Fig. 2 is a plan view of the carriage showing in dotted lines the gun in a hori-
zontal position also the graduated scale and index for indicating the traverse of the
carriage.
Fig. 3 is a rear elevation partly in section showing the construction and
arrangement of parts forming the carriage.
Fig. 4 is an enlarged detail sectional view of the mechanism for supporting and
taking up the recoil of the gun also for elevating and depressing the same and for
the supply and equalization of pressure of air in the pneumatic cylinders, and
Fig. 5 is a sectional view on the line of Fig. 1.
In these drawings, A represents the sole or racer-plate which is securely bolted
to. the foundation upon which travels a roller ring A' adapted to support a circular
bed-plate A². This bed-plate A2 is provided with cross-stays A³ which serve to
stiffen the plate, also form bearings for a series of centralising rollers A* thus
obviating the necessity of a central pivot thereby producing a superior and neater
construction and reducing the cost of manufacture.
The checks B B of the carriage are mounted upon and securely bolted to the
bed-plate A being further supported by a transom B. In the upper portion of the
cheeks large trunnion bearings B2 are formed and are provided with square caps b
as shown.
Arranged around the gun are a number of pneumatic recoil cylinders C. In
this instance four are shown cast in pairs and connected by strong plates c which
are provided with large trunnions c¹ adapted to be supported in bearings B' formed
in the checks B of the carriage and designed to support the entire weight of the
gun and apparatus for arresting the recoil, also acting as the main pivot in
elevating or depressing the gear and are held securely in position by the nuts .
These plates care further provided with ways c³ for the reception of blocks or
slides in which the gun is trunnioned, and are provided at their forward ends
each with a cross head which confine the extreme ends of the piston rods cⓇ by
means of the nuts e as shown in Fig. 4.
As these recoil cylinders are of similar construction a description of one will

page_text: suffice to give a clear understanding of the device. A cylinder C Fig. 4 is pro-
vided with a suitably packed gland at its forward end through which passes a
hollow piston rod ce provided with a piston head. A chamber in the head com-
municates with the forward portion of the cylinder through the openings c" and
with the rear portion by means of an opening c in the piston head, coincident with
the bore of the piston rod in which a tapering rod or valve D having one end
secured in the rear head of the cylinder and the other end works in the opening of
the rod as shown. In the drawings this rod D is shown of the same diameter at
its extreme ends for the purpose of closing the communicating passage ways
between the spaces on each side of the piston-head. As the tapering portion of
the rod or valve is passed by the chamber in the head of the piston in the recoil of
the gun the compressed air is allowed to pass to the forward portion of the cylinder
and as the piston continues to descend and the opening in the piston head passes
the portion d' of the valve or rod D the passages are closed and an amount of air
sufficient to form an elastic cushion for supporting the gun and accompanying
mechanism is trapped. It will be understood that when the parts are in the
position shown in Fig. 4 the cylinder is filled with compressed air offering such
resistance as to take up the recoil when the gun is fired and to facilitate this opera-
tion the taper of the rod begins at a point below the piston-head so that as the
gun recoils the air will be under great pressure and without an outlet thereby the
greater part of the shock occasioned by the recoil of the gun will be taken up in
the movement of the piston from the position shown to the point where the valve
rod D begins to reduce in diameter. As the piston head descends, the taper portion
of the valve rod passes the interior chamber c of the piston head and the air is
gradually released and will pass into the forward end of the cylinder where it
remains until the gun is loaded and ready to be elevated when the elevating gear is
operated and the air is released and passes to the opposite end.
E indicates pipes connecting the recoil cylinders in order to maintain air
equilibrium of pressure and by which they are supplied with air. E' is a check
valve and cock connecting with the compressors that supply the air.
An elevating band F is secured in position on the mortar in front of the trunnion
band by the bolts F. H are elevating racks which are secured to the underside of
the recoil cylinders and with which engage pinions H¹ mounted on a short shaft
having bearings on the cheeks of the carriage. On the projecting end of this shaft
outside of the carriage is mounted a friction worm-gear H which is operated by
means of worm H shaft H and hand wheel H³. By turning the hand-wheel in
either direction causes the elevation or depression of the gear and the number of
degrees will be indicated by the index-finger 1 on the side of the carriage.
Traversing the carriage is performed by means of the hand wheel K the motion
of which is communicated to the carriage through the medium of shaft K¹ bevel
gears K' shaft K' worm gear K shaft and pinion K and circular rack K' which is
secured to the racer plate A. The degrees of traverse are indicated by a circular
graduated scale which is provided on to the wall plate L and an index finger L'
attached to the circular bed-plate A' is designed to travel over said scale-plate.
To prevent the carriage from lifting when the mortar is fired at a low angle
sustaining clips M are employed which engage an overhanging flange M' of the
racer plate A.
To supply any deficiency of air in the recoil cylinders arising from slight
leakages a small hand air pump N is attached to the carriage.
The operation of the carriage is as follows;-
By the arrangement of parts herein shown and described the recoil cylinders
can be supplied with compressed air at five hundred (500) pounds pressure, by
hand power, in thirty minutes with a portable air-compressor. Immediately
following the completion of this step in the operation, the hand wheel H' is
revolved and through the train of gearing motion is communicated to the mortar
which is depressed into almost a horizontal position in which position it is loaded.
The gun being loaded the hand wheels H' controlling the elevating mechanism and

page_text: hand wheel K controlling the traversing mechanism are revolved and the gun is
trained to the desired position or elevation of inclination which will be indicated by
the index fingers when the gun is ready for firing. After firing the recoil is taken
up by the pneumatic recoil cylinder and the gun automatically returned to battery
when the operation as above described is repeated.
In describing this invention I do not claim the use of compressed air for taking
up the recoil and counter-recoil of the gun as the idea is described in a previous
Patent.
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 1
claim is :-
1. In a gun mount having an all-round traverse the circular bed or table pro-
vided with suitable braces or stays and means for centralizing the carriage on said
circular bed-plate or table substantially as and for the purpose described.
2. In a gun mount having an all-round traverse and a circular bed-plate or table
the cheeks suitably secured and supported thercon and provided with trunnion
bearings at or near the top substantially as and for the purpose set forth.
3. In a gun mount having an all-round traverse a circular bed-plate or table
and cheeks provided with trunnion bearings at or near the tops thereof a series of
pneumatic cylinders arranged around the gun in pairs and provided with trunnions
adapted to be supported in the bearings in the checks of the carriage substantially
as described.
4. In a gun mount having an all-round traverse circular bed plate or table
cheeks secured thereon and supporting in bearings the recoil cylinders which are
cast in pairs and arranged on each side of the gun slide blocks into which the gun
is trunnioned said slides adapted to work in ways formed between the recoil
cylinders and provided with cross heads tubular piston rods chambered piston heads
having communicating passages and a differential cylindrical valve substantially as
and for the purpose set forth.
5. In a gun mount having a series of recoil cylinders arranged two on each side
of the gun and trunnioned in the cheeks of the carriage the supply and equilibrium
pipes a check valve substantially as described.
6. In a gun mount a series of recoil cylinders arranged as described slide blocks
working in ways between the recoil cylinders the elevating band secured to the
slide blocks and mechanism for elevating and depressing the gun to be controlled
by hand wheels and a system of tell-tales for indicating the elevation and traverse
of the gun substantially as set forth.
7. In a gun mount a series of recoil cylinders arranged as described and pro-
vided with trunnions which are supported in bearings in the cheeks of the carriage
slide blocks working in ways between said recoil cylinders and into which the gun
is trunnioned the elevating racks H pinions H₁ friction work gear H³ worm H
shaft H and hand-wheel H substantially as described.
Dated this 28th day of December 1891.
W. P. THOMPSON & BOULT,
Agents for the Applicant.