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United States. Army. Ordnance Dept.

Handbook of artillery : including mobile, anti-aircraft and trench matériel online

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to the top of the chest. The reel is built up of two steel spool flanges
mounted on a shaft, a spool riveted to the right flange and a basswood
spool hub mounted between the spool flanges.

The spool may be operated from either side. The crank on the right
side is mounted on the shaft, and when not in use it can be removed
and placed in its provided receptacle. The crank on the left side is
connected with the spool through an 18 to 40 gear reduction. The
crank shaft is fitted with a driving gear which meshes with a pinion
18322820 11 (159)



160



on the shaft of the spool. Chains are provided on either end of the
frame for locking the cranks when not in use.

The reel is also fitted with a brake for controlling the speed of rota-
tion when allowing wire to run out. The brake lever is pivoted on
the brake-lever pin, and operated by a thong attached to the lower





REEL FOR CAISSON, MODEL OF 1917.

end of the lever. By pulling the thong the upper end of the lever is
made to drag on the inside of the rim of the left spool flange. A
brake-release spring, attached to the upper end of the lever, and a lug
on the left shaft bearing, keeps the brake open when not in use.

THE AUTOMATIC POLE SUPPORT.

Late designs of limbers for 75-millimeter and 3-inch gun materiel
are fitted with an automatic pole support.

The pintle hook has a lug formed on its lower side, which projects
backward and bears against the lower side of the lunette on the
drawn vehicle, thus preventing the vertical rotation of the pintle.



PIMTU BEMl.n* 6UIDC-



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SECTIONAL DIAGRAM OF POLE SUPPORT.

The pintle bearing is pivoted by trunnion bolts permitting rota-
tion in the vertical plane. A spring rod is pinned to a lug on the top
of this bearing and carries the pole supporting spring. This spring
is held between a collar on the rod and the pintle bearing guide so
that when the weight of the pole on the coupled vehicle is put on the
pintle it tends to compress the spring until the load is supported by it.

On the pintle bearing bolt is another spring, which is compressed
when the pintle is drawn back, thus relieving the shock of starting.



4.7-INCH GUN MATERIEL, MODEL OF 1906.



The 4. 7-inch, model of 1906, is a mobile field gun, designed to fire
shrapnel or shell at greater ranges than the 75-millimeter guns. In
order to increase the range, a 45-pound shell is provided to replace
the old type 60-pound shell. The former projectile gives consider-
ably higher muzzle velocity and longer range than the 60-pound pro-
jectile. The life of the gun before relining is approximately 5,000
rounds.

Using the 60-pound shrapnel, a muzzle velocity of 1,700 foot-
seconds is obtained, with a maximum range of 7,550 yards (6,903
meters) at an elevation of -15. With the 45-pound shell, with a
muzzle velocity of 2,050 foot-seconds, a maximum range of 8,700
vards (7,900 meters) at an elevation of 15, under normal conditions.




VIEW SHOWING CARRIAGE AND LIMBER IN TRAVELING POSITION.

The 4.7 inch field gun is mounted on a carriage of the long-recoil
type, in which the gun is permitted a sufficient length of recoil on the
carriage to render the latter practically stationary under firing
stresses. The gun, in recoil, is controlled by two spring cylinders, and
a hydraulic cylinder, which is filled with 25J pints of oil. In recoil,
the oil in the hydraulic cylinder is forced from one side of the piston
to the other through small portholes. The area of these ports are
calculated to make the resistance which the liquid offers, plus the re-
sistance of the springs, such that the wheels will not jump from the
ground when the gun recoils. In counterrecoil the oil is forced back
through these small ports with the result that the return of the gun
into battery is so eased and regulated that shock and consequent
derangement of the aim is almost eliminated. To properly return
the gun. to battery at high angles of elevation, the springs are assem-
bled with an initial compression of approximately 1,500 pounds in
each cylinder.

061)



162




163




164

Tko carriage is equipped with a single trail, composed of two pressed
steel flasks, and is anchored in the ground by a spade when in action.
When traveling, the trail is supported by the carriage limber which
may be drawn by either a truck or tractor. On account of the single
trail the maximum elevation of the gun, without digging in the trail,
is only 15. The allowable transverse movement is 140 mils, or
about 8.

The motorized equipment of each gun carriage, as indicated below,
consists of a carriage limber, which supports the trail when traveling,
and three caissons, which carry ammunition.

4.7-inch gun and carriage, model of 1906.
4.7-inch gun carriage limber, model of 1905.
4.7-inch gun caisson, model of 1916 or 1917.
The above materiel is entirely of American design and manufacture.




LEFT FRONT VIEW OF CARRIAGE EQUIPPED WITH BAND BRAKES.

Weights, dimensions, and ballistics.

Weight of gun pounds. . 2. 688

Total length , ..inches. . 134. 927

Rifling Right hand, 1 turn in 50 calibers at origin to 1 turn in 25 calibers
at 14.9 inches from muzzle, thence uniform.

Weight of projectile, base fuzed shell and shrapnel pounds. . 60

Weight of point fuzed shell do 45

Weight of powder charge ounces. . 95

Weight of cartridge case pounds.. 8

Muzzle velocity (60 pound shell and shrapnel) ft. per sec . . 1, 700

Muzzle velocity (45 pound shell) do 2, 050

Maximum range at 15 elevation, of 45- pound shell yards . . 8, 700

Maximum range at 15 elevation, of 60-pound shrapnel do 7, 550

Weight of carriage, complete (without gun) pounds. . 5, 320

Weight of gun and carriage, fully equipped do 8, 069

Diameter of wheels inches. . 61

Width of wheels do.... 6

Height of axis of gun do 51.59

Maximum angle of elevation (gun or carriage) degrees . . 15

Maximum angle of depression (gun or carriage) do 5

Amount of traverse mils... 140(7.8)

Height of line of sight inches. . 53. 92



1G5




166



4.7-INCH GUN AND CARRIAGE, MODEL OF 1906.

The gun is of the built-up type, and consists of a tube, jacket, lock-
ing hoop, and clip. The jacket covers the rear half of the tube, and
projects beyond the tube at the rear to form the breech recess. The




FRONT VIEW OF CARRIAGE EQUIPPED WITH TIRE BRAKES.

jacket is equipped with a recoil lug on the underside for connecting
the recoil cylinder. The clip is a short hoop near the muzzle and is
fitted with guides to guide the gun in the cradle on recoil.



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BREECH MECHANISM.

The breechblock is of the interrupted screw type having four threaded
and four plain sectors. It is operated by a handle which swings from
left to right, turning and withdrawing the breech with one motion.
An extractor is fitted for throwing out the shell case when the breech
is opened after firing.



167

The firing mechanism is of the type known as a continuous-pull
mechanism; that is, the mechanism is cocked and fired by the pull on
the lanyard or by downward pressure on the firing handle located at
the left side of the breech.

The carriage is composed of the following principal parts: Wheels,
axle, the cradle (for housing and supporting the recoil mechanism
of the gun), trail, traversing and elevating mechanisms.

The gun carriage is of the long-recoil type, in which the gun is
permitted to recoil on the carriage to render the latter stationary
under firing stresses. The recoil mechanism consists of an hydraulic
cylinder filled with oil, placed parallel to the gun, and attached to
the cradle The recoil cylinder controls the backward movement
of the gun upon discharge, and the springs function to return the
piece to battery position.




FIRING MECHANISM.



The recoil and counterrecoil mechanism is of the hydro-spring type,
and consists of two parallel steel tubes (the spring cylinders) fitted
into a frame and surrounded by rails which form the gun slides and
the cradle. The recoil cylinder is fitted between these two.

The piston and spring rods secured to the gun lug and recoil with the
gun, while the spring cylinders and recoil cylinder remain stationary.

The recoil is of the constant type, being 70 inches when the gun is
fired at zero elevation, and is somewhat greater at higher angles, due
to the action of gravity on the recoiling parts. The recoil cylinder
uses hydroline oil as the buffer medium. Throttling is obtained by
three throttling bars running lengthwise of the cylinder, which are
of varying height to give a throttling effect with corresponding
slots in the recoil piston. A counterrecoil buffer is fitted in the piston
rod to take up the shock when the springs return the gun to battery.



168




169

The trunnions on the cradle are mounted in bearings formed by a
yoke which swivels in a pintle bearing provided at the front of the
trail.

Traverse is obtained. by means of a handwheel and screw mounted
on the left side of the trail, which swings the yoke, it carrying the
gun with it. A traverse of 70 mils on each side of center is possible.

Tho piece is elevated by a double screw type of mechanism. The
upper end is attached to the cradle and so raises and lowers it.




FRONT VIEW OF CARRIAGE EQUIPPED WITH BAND BRAKES.

The screw is operated through gearing by two handwheels, one on
each side of the trail. From 5 degrees depression to 15 degrees
elevation is obtained.

The trail is of the solid type, made up of flasks of channel section.
It houses the axle and carries the pintle bearing in which the top
carriage, or yoke, swings. A tool box is fitted in the trail, and a
seat is provided on each side of the trail for the cannoneers. The
lunette transom is fitted about 27 inches from the rear of the trail,
and carries a bearing that fits the limber pintle. A trail prop is



170



provided for supporting the trail when limbering. The spade can
be released and folded up on the trail when traveling.

A traveling lock is provided on the trail for locking the gun when
traveling. The piston rod and spring rods must be disconnected
before the gun can be drawn back far enough to lock.




REAR RIGHT SIDE VIEW OF CARRIAGE.



The wheels are 61 by 6-inch rubber tires, and are equipped with
band brakes. Some of the older type of vehicles have steel tires




ELEVATING AND TRAVERSING MECHANISMS.

and are fitted with tire brakes. An armor plate shield is fitted to
the carriage for the protection of the personnel.

The sighting is similar to the 3-inch gun, model of 1902.

The instruments for sighting and laying the piece include line
sights, a rear sight, a front sight, a panoramic sight, and a range
quadrant.



171




172

The line sight consists of a conical point as a front sight and a
V-notch as a rear sight. These are located on the jacket of the gun,
and are useful for giving gen eral. direction to the gun.

The rear and front sights are used for direct aiming. The rear
sight is a peep sight mounted on range scale shanks on left side




REAR VIEW OF CARRIAGE EQUIPPED WITH BAND BRAKES.

of the cradle. The front sight consists of a pair of cross wires
mounted in a ring about three feet ahead of the rear sight.

The sight shank has a socket in which the standard United States
panoramic sight may be mounted.

On the right side of the cradle is mounted the range quadrant,
which has in combination with it the angle of sight mechanism. For
indirect fire the gunner on the right of the piece lays for range with
this instrument, and the one on the left lays for direction only.



173




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174

Fixed ammunition is used with this gun; shrapnel and high ex-
plosive shell being used. The base fuzed stell shell and the shrapnel




FRONT VIEW OF CARRIAGE EQUIPPED WITH TIRE BRAKES.

weigh 60 pounds. The point fuzed sheel weighs 45 pounds. Gas
shells are also issued and are identical with the 45-pound steel shell.



4.7-INCH GUN CARRIAGE LIMBER, MODEL OF 1905.



The limber, a two-wheeled vehicle to which the trail of the car-
riage is fastened, forming, with the gun carriage, a four-wheeled car-
riage for the gun when traveling.

The carriage limber is designed to be used with the connecting
pole for attachment to a tractor and to support the trail in traveling.
The limber is made of metal throughout, wood being used only in
the spokes and felloes of the wheels. The principal parts are the
wheels, axle, frame, top carriage, pole socket, and connecting pole.

The top carriage is a steel casting, formed to accommodate "the trail
of the 4.7-inch gun carriage, the trail resting on it when en route.





FRONT VIEW OF LIMBER.

The front end of the top carriage is provided with three rollers which
rest and run on the top carriage rail; the rail edge being equipped
with clips to prevent accidental dismounting. A spur located on the
top carriage which enters the trail, holds the trail and top carriage in
line.

The wheels are 51 inches in diameter, 4 inches wide, and are rubber
tired. The hubs are similar and interchangeable with those on the
wheels of the carriage. The axle is hollow and is made from a single
piece of forged steel.

A bucket holder with straps is located on each side brace for car-
rying four canvas watering buckets.

18322& 20 12 (175)



176




177

The doubletree, singletrees, and pole complete are omitted for
motorized batteries and a competing pole is used in their place.
The standard short pole with lunette is fitted for motor traction and
for horss-drawn equipment the longer pole may be substituted.

Weights and dimensions.

Weight, complete, including spare connecting pole pounds. . 1, 750

Weight of limber with gun and carriage, traveling position do 9, 818

Diameter of wheels (rubber tired) inches. . 51

Width of track do 60

Free height under limber and carriage do 16. 8



4.7-INCH GUN CAISSON, MODEL OF 1908.



The 4.7-inch gun caisson is constructed upon the same general
plan as the 4.7-inch caisson limber. The wheels, axles, pintles and
bearings, lock bars, and most of the implement fastenings and chest
parts of the two vehicles are exactly similar and interchangeable.

The principle parts of the caisson are the wheels, axle, axle bearings,
ammunition chest, pintle, connecting-pole socket, connecting pole,
prop, apron, and brake.

The flange-steel front plate and chest door (upper) of the limber
are on the caisson replaced by armor plates, for the protection of




RIGHT SIDE VIEW OF CAISSON.

ammunition servers from small arms and shrapnel fire, An apron
of armor plate is hinged to the bottom of the caisson chest and extends
to within a short distance of the ground for the same purpose. This
apron swings forward against the bottom of the ammunition chest
to clear obstructions in traveling, and is held in that position by
latches attached to the sides of the chest.

The pole socket of the caisson is made longer than on the caisson
limber, and is fitted with rollers which serve as wheel guards. The
connecting body is made of steel tubing, its rear end is finished to
fit the pole socket, and is provided with a seat for the rectangular
key which secures the connecting p6le to the socket. A prop of

(178)



179

steel tubing with a bronze foot is attached to the connecting pole for
a support when the caisson is unlimbered ; when not in use the prop
is swung up under the connecting pole and is held by chains.

The beams of the road brake are hinged in brackets riveted to the
^ chest front. The brakes are built up of flange and forged steel parts
and carry cast iron shoes to bear against the wheel tires.

Hangers for a spare connecting pole and a bracket for a spare key
are provided on the chest. The ax, hatchet, lantern, and watering
bucket fastenings are similar, and located like those on the caisson
limber. The paulin on the caisson chest serves as a seat cushion
and on either side of the chest handrails provide handholds for the
cannoneers, when mounting or dismounting.

The opening between the upper and lower intermediate plates
011 the left side is utilized to carry a two-gallon oil. can. Of every
four caissons, three carry oil cans containing lubricating oil, and the
fourth, hydroline oil, the contents of each being indicated by a name

plate. . : ' i

Weights, dimension, etc.

Weight of caisson limber, empty (without implements or ammunition), pounds. . 1, 821

Weight of implements carried do 85

Weight of ammunition carried do 2, 055

Weight of limber, fully equipped and loaded do 3, 961

Weight of caisson, empty (without implements or ammunition). do 2, 05J8

Weight of implements carried (including spare connecting pole) do. 147

Weight of caisson fully equipped and loaded do 4, 260

Hounds of ammunition carried in caisson limber 28

Rounds of ammunition carried in caisson 1 28

Diameter of wheels inches. . 60.

Width of track do. ... 60.

Free height under caisson do 19. 55

Turning angle degrees. . 80



4.7-INCH GUN LIMBER, MODEL OF 1908.



Tho limber is a two-wheeled vehicle provided with an ammuni-
tion chest for the transportation of ammunition for the 4.7 inch gun.

The principal parts are the wheels, axle, ammunition chest, pintle,
pole socket, pole, doubletree, singletrees, and neck yoke.

Tho wheels and the wheel fastenings are the same as, and are inter-
changeable with, those on the carriage. The axle is hollow and of a
single piece of forged steel. It is secured to the chest by axle bear-
ings riveted to the sides of the chest and to the flanges of the inter-
mediate plates.

Tho ammunition chest is built up of flange steel and is divided
into an upper and lower compartment by intermediate plates. Cor-




VIEW SHOWING GUN CAISSON AND LIMBER, LIMBERED.

responding holes in the middle and rear diaphragms are connected
by conical brass tubes called connecting pieces, which are cut away
on top to save weight. These connecting pieces support the front
end of the cartridge case and serve to guide the projectiles. The
chest doors close against the heads of the cases so that the cartridges
are firmly held in position. Suitable clearances are cut in the flange
of each cartridge pocket to enable the cartridge hook to get back of
the rim of the case in withdrawing it from the chest.

The doubletree is mounted upon a doubletree pin projecting up
through a boss on the forward end of the pole socket. A limber
prop is hinged to the pole socket. When traveling, the prop is drawn
up to the rear and held by a chain.

The pintle swivels 300 in the bearing, but is normally held in a
vertical position by a spring bolted to the pintle bearing support.

(180)



181

The right side of this vehicle is equipped with fixtures for holding a
pick, hatchet, and pickax; while on the left side provision is made
for a shovel.

The paulin on the top of the chest is held in place by straps suitably
fastened. Other fastenings on top of the chest are for a picket rope,
an ax, and a limber blanket. On the front are attachments for a
wrench and a pole prop. The cartridge hook for use in withdrawing
the cases and projectiles from the chest is fastened on the left side
of the caisson. A spanner for tightening the hub bands of the wheels
is carried between the intermediate plates.

The pole, doubletree and singletrees, and neck yoke arc standard
and interchangeable with those on any limber of the battery. Double-
tree chains attached to the chest body prevent excessive movement
of cither end of the doubletree.

The 4.7-inch gun limber, model of 1908, is only used in connection
with the 4.7-inch gun caisson, model of 1908, both being of American
design and manufacture. These vehicles are used with motorized as
well as horse-drawn batteries of 4.7-inch gun materiel.



4.7-INCH GUN CAISSON, MODEL OF 1916.



The caisson, model of 1916, is a two-wheeled vehicle with an
armored ammunition chest for the transportation of ammunition for
the 4.7-inch gun. This vehicle is designed to carry 28 rounds of




RIGHT FRONT VIEW SHOWING CHEST DOORS OPEN EXPOSING DIAPHRAGMS.

the fixed type of ammunition. The body is suspended in such a
manner that 7 rounds are carried below and 21 above the axle.

The chest is built entirely of steel, but the upper door, rear plate, and
an apron hung under the body are of armor plate for protection of the
ammunition servers in the rear, from shrapnel and small-arms fire.
The doors open to the front, and when closed bear on the heads of
the shells. Suitable fastenings are provided on this chest for carry-
ing the usual complement of tools and accessories, also brackets for

(182)



183




184

carrying fuze boxes on the outside of the chest. The chest provides
scats for two cannoneers.

This caisson is provided with an ammunition chest of sufficient
size to carry either shrapnel or high-explosive steel shells. It is
also equipped with fixtures for holding picks, shovels, and other
tools on the outside of the ammunition chest. By removing the
connecting pole, and adding double and singletrees, this vehicle may
be transformed into a caisson limber suitable for horse traction.




FRONT VIEW OF GUN CAISSON.

The principal parts of the vehicle are the wheels, axle, ammunition
chest, pintle, brake, connecting pole socket, and connecting pole.

The wheels and wheel fastenings are the same as, and are inter-
changeable with those on the carriage. The axle is fastened to the
chest by axle bearings riveted to the chest sides.

The body of the chest is of flange steel riveted together forming
the top, bottom, and sides of the chest. The chest doors close
against the heads of the cases so that the cartridges are held firmly
in position. Suitable clearances are cut in the flange of each car-



185

tridge pocket to enable the cartridge hook to get back of the rim of
the case in withdrawing it from the chest. The chest doors open to
the front, the lower door being hinged to the bottom of the chest,
the upper to the top of the chest, and by means of a lock bar, the
doors are locked.

The armor-plate apron is hinged to the bottom of the caisson, so
that whoii traveling it may be swung backward against the bottom,
where it is held by latches on the chest sides.

The vehicle is equipped with a short connecting pole in front pro-
vided with a suitable prop for holding the pole up when the caisson
is at rest. At the rear is the standard pintle enabling other vehicles
to be connected en train.

On the tire brake models, brackets are riveted to the end of the
chest. To these brackets are pinned the brake beams by the same
kind of leverage system as on the carriage. The brake shoes are
brought to bear on the tire by pressure on the brake lever, the brake
lever and segment being on the left side of the vehicle.

The brake band model like the tire brake, has the brake lever on
the left side of the chest and is of the contracting band brake type.
Pulling up on the brake lever, causes the brake bands to grip the
drums bolted to the wheels.

The top of the chest has provision made for carrying a picket rope
and spare connecting pole, an ax, and straps for a paulin that also
serves as a seat cushion. The left side carries the pick, mattock and
hatchet; the right, a long-handled shovel, cartridge hook and pole
socket key. On the back are riveted a bucket holder, lantern bracket
and a foot rest.

Between the intermediate plates in front, an oil can is carried on
the right side, a fuze box on the left, and also a spanner wrench. In
every battery, one caisson is provided with a hand reel containing
one mile of wire as for the caisson model of 1917. See page 159.

Weight, dimensions, etc.

Weight of caisson, empty with implements or ammunition pounds. . 2, 565

Weight of implements carried including spare constructing pole do 180

Weight of ammunition do 2, 067

Weight of caisson fully equipped and loaded do 4, 812

Round of ammunition carried 28

Diameter of wheels inches. . 61

Width of track do 60

Free height under caisson ..do.. 20.8



4.7-INCH GUN CAISSON, MODEL OF 1917.



The caisson, model of 1917, is a two-wheeled vehicle equipped
with an armored ammunition chest for the transportation of ammuni-
tion for the 4.7-inch gun. The two most important changes from
previous models are: The substitution of a band brake for a tire
brake, and a spring support for the ammunition chest.

The principal parts of the caisson are: The wheels, axles, spring


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Online LibraryUnited States. Army. Ordnance DeptHandbook of artillery : including mobile, anti-aircraft and trench matériel → online text (page 9 of 19)