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ACTION OF GEAR. PLATE 62.
The diagram shows the relative positions of the various parts of the mechanism when the breech block is screwed home. The action is as follows:-
To Open Breech, pressure is admitted (by means of the control valve B1), into the top of the cylinder through port a. The exhaust, in escaping through port b, lifts the flap c, and escapes through the port d, and thence through pipe e to control valve, the flap f being pressed against the face plate by the exhaust. The valve remains in this position (i.e., full open to exhaust), while the breech screw is rotated; the cam i.k.m.h. travelling past the roller g from h to I meanwhile.
When I comes into contact with the roller g, the latter is pushed to the left and the valve commences to travel down; when j is reached, the lower edge of flap coincides with the upper edge of the port d; while the portion j-k of the cam is passing the roller the flap f moves over d, diminishing the effective area of the port, thus increasing the resistance to exhaust on the back of the piston and retarding the motion of the breech block as it starts to swing clear of the gun.
During the time that i.j.k. has been passing the roller g, the catch lever n has been pressing against the stop O on roller lever, under the action of spring p, but the stop O does not travel during this stage sufficiently far for the catch to act. When the point k reaches the roller, the latter begins to move to the right under the action of spring q, with the result that by the time point l is in contact with g, the port d is fully uncovered.
Shortly after this, g begins to move to the left, the valve travels forward, and by the time m is in contact with g, the port d is completely covered (the carrier now having swung right out), and the resistance to the exhaust acting on the back of the piston, is at a maximum. The point m is at a greater distance from the centre of the came than the point k, and the length of lever n is so arranged that when m is in contact with g the level n no longer rides on the stop O, but the stop O itself drops in effect into the notch in lever n, thus holding the roller lever, and keeping the valve stationary.
To Close Breech, the pressure is admitted through pipe e to the valve, and thence, through ports d and b, to the lower end of the cylinder (the pressure of water having lifted flap f and pressed flap c against the valve face). During the whole time that the breech block is being swung in and screwed up, the valve remains open, the roller being held clear of the came by the catch lever n, but at the end of the screwing up process the catch between n and O is released by the motion transmitted to lever n, by the pin r on cam. When the roller lever is thus released, the roller is pressed (by means of spring q), on the face of the cam again at point h. The valve is thus moved upwards so that flap c covers port b, cutting off the supply of pressure water just as the breech is screwed home.
Note. - The speeds for opening and closing of the breech should be adjusted so that the time for each of these operations shall not be less than 4.5 to 5 seconds.
AIR BLAST GEAR.
PLATES:-
General arrangement..63
Diagrammatic arrangement...64
Gear on side - Diagrammatic.. 66
Gear on side with certain breech fittings (Gen Arrgt.)... 61
Gear on side with certain breech fittings (Gen Arrgt.)... 65
Air at pressure not exceeding 3,500 lbs. per sq. inch is led from the main air service in the ship through a Centre Pivot K1 at the bottom of the revolving trunk, to reservoirs L situated at the right and left of the central hoists.
From here a separate service supplies each gun, by means of a cross connecting pipe and a series of stop valves C1, C2, C3 and C4, either or both guns can be supplied from the right hand or left hand series of reservoirs.
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After leaving the reservoirs the air passes through a Reducing Valve M which I lowers the pressure to 1 ,000 lbs. per sq. inch. A reducing valve and a 1,000 lb. Gauge are provided for each gun, and they are situated in the pocket for the breech number.
To allow for the oscillation of the mounting about its trunnion, a length of Flexible Hose N (see Plate 66) is inserted between the standing pipe which leads from the reducing valve M and the pipe secured to the trunnion arm
The connection on the arm is brought as close to the axis of oscillation as possible in order to reduce the bending of the flexible hose to a minimum.
To allow for the Recoil of the gun the pipe secured to the trunnion arm is led into one end of a hollow rod e1 secured to the slide, and this rod passes through the Sliding Cylinder E secured to the gun cradle. Pressure is admitted to the chamber of the sliding cylinder through slots e3 in rod e1 and is led from there to the admission valve F.
There are 3 chambers in the sliding cylinder; two of them being for breech operating gear as already described, and the third for air blast as now under consideration.
The Admission valve F is carried on the gun close to the breech hinge, and it is automatically opened as the breech opens by cam H on the carrier, which, engaging the end of lever G, depresses it and opens the valve against the action of the spring f1.
The admission valve is also arranged so that it may be worked by hand if required.
CHAIN RAMMER.
PLATE 67.
GENERAL DESCRIPTION.
The gear is the same as for Pair 15-inch Mark I mountings. The Chain Pinion C. 1 has teeth of involute form, driven by a Seven Cylinder Engine C of the swashplate type. The chain in passing over the pinion is guided by two cam plates C2 of suitable form. The reason for these guides is that with teeth of involute form, the portion of chain following the driven link is slack, and requires to be guided in the correct path for giving uniform motion.
The Swashplate Engine is of the usual construction, and calls for no specia] description. Pressure on the axial coupling turns the engine clockwise.
The rammer is controlled automatically as regards its stroke, cushioning, and pressure throttling by means of an Intercepting Valve A placed between the working valve B and the engine. It is geared with the latter so as to throttle the exhaust towards the ends of the " in and out " strokes of the rammer, and bring the chain quietly to rest.
For reducing the speed and length of stroke for ramming cordite a pedal operated stop is provided.
The intercepting valve A is provided with upper and lower chambers, a. I and a.2, which are simply enlargements in the two pipes 1 1, and 2 2, connecting the working valve and engine. The lower chamber a.2 is provided with a port at each end, between which travels a shuttle valve a.3 mounted between adjustable collars on rod a.4. This rod is geared with the engine through guide bar D, bellcrank E, connecting rod F, screw shaft G, and skew wheel H which is driven by wheel J on the axis of chain pinion Cl.
The upper chamber a. 1 is provided with a single port only, and a valve which is solid with its rod a.5. This valve serves two purposes
(1). To throttle the exhaust towards the end of the "Full Out" stroke of the rammer, and
(2). To close the port against exhaust at the end of the cordite stroke.
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On the rear end of rod a.5 is a collared nut a.6, engaging a lever K, pivoted on guide bar D. This guide bar is also provided with an abutment d.1, against which collared nut a.6 is held by the compression spring a.7 on the forward end of the valve. The upper end of lever K engages a stop p.l on bellcrank pedal P, which is pivoted on the Valve casing. Pedal P is provided with a projection p.2 (Figs. 1 and 3 which, on the pedal being depressed, is interposed in the path of the adjustable stop m1 on the rammer working lever M; this limits the stroke of lever M and consequently the speed in ramming cordite. Depression of the pedal lifts the stop p.1 clear of the toe of lever K.
ACTION OF GEAR.
Fig. 1 shows the positions of the valves a.3 and a.5, at the end of the "In" stroke. Valve a.3 has just closed the exhaust port in lower chamber a.2, and brought the rammer to rest. Both valves have moved in the direction of the arrow, which is also the direction of flow, the lead of the pressure and exhaust being indicated respectively by red and blue colour.
Assuming a full "In" stroke to have just taken place with pedal P in the position shown, the upper valve a.5 has been moved to compress spring a.7 by the action of lever K, which is connected to guide bar D, and pivots about stop p.1 on the pedal as a fulcrum.
RAMMING A PROJECTILE
Fig. 2 shows the positions of the ports at the end of the "Out" stroke in ramming a projectile. When lever M is put over to Ram pressure is admitted from the working valve to the lower chamber a.2 of intercepting valve A, and blowing back Shuttle Valve a.3, passes to the axial coupling on engine, turning it clockwise to ram. Exhaust from the engine returns through the upper chamber a.l to the working valve. As the rammer advances, both valves are moved rearwards to throttle their respective ports, by guide bar D, which is geared to the engine in the manner already described. In this operation, the motion of the upper valve a.5 is controlled by the action of lever K, the upper end of which turns about the stop p.1 on pedal P as a fulcrum.
Arrows show the direction of travel of the valves and of the flow as before.
When ramming a projectile, the pressure and exhaust ports remain sufficiently open to allow full speed of rammer until the projectile is seated. Throttling sufficient to bring the chain to rest only takes place in ''drill,'' when no projectile is used in this case both ports are gradually closed during the last foot of extreme stroke of the chain.
RAMMING CORDITE.
Fig. 3 shows the positions of the ports at the end of the stroke in ramming cordite. For this operation, the pedal P is depressed and lifts the stop p.1 clear of the toe of the lever K, at the same time opposing another stop p.2 in the path of an adjustable projection m.1 on the rammer lever M, reducing the stroke of lever M and therefore the speed in ramming as the working valve B is not fully open to pressure. By movement forward of lever M, pressure is admitted from working valve to lower chamber a.2 of intercepting valve, and blowing back the shuttle, which is in the position shown by Fig. 1, passes to engine, causing the rammer to advance. Both valves in the upper and lower chambers now move as one, the spring on the upper valve keeping the collared nut a.6 firmly pressed against the abutment d. 1 on guide bar D. As the upper valve a.5 is moved rearwards, it first throttles its port, and then closes it altogether, and so determines the stroke of the rammer.
The connections shown are for the Right Hand Engine. For the left hand engine, the two pipe connections between the intercepting valve and the engine are reversed, in consequence of these engines being arranged to always turn clockwise when pressure is admitted to the axial coupling.
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ADJUSTMENT OF STROKE, ETC.
An instruction plate on the loading arm gives general directions for the adjustments of the intercepting valve. As these adjustments are interdependent, it is necessary to proceed as follows:-
Adjust screwed rod G in threaded spiral pinion H so that connecting rod F, bellcrank E, and guide bar D bring lever K into such a position that stop p.1 on pedal, P just engages toe of lever K when rammer is "Home" as shown in Figure 1. The space between the rear end of the valve body and the front edge of locking plate a. 10 on lower rear spindle should be about 45 inch when stop p.1 comes into action.
This adjustment is obtained by removing the cover c.3 from the rammer friction clutch gear and adjusting the position of the spiral pinion H relative to the spiral wheel J.
Clockwise arid Anti-Clockwise.--These terms whenever used below assume that in all cases the operator is looking towards the intercepting valve body.
Pressure Throttle when Ramming Light-To adjust throttle of pressure supply remove locking plate a.10 from lower rear spindle and turn spindle a.4.
Clockwise to cut off pressure later.
Anti-clockwise to cut off pressure earlier.
Cushioning in Ramming Light.-This consists of throttling and then closing the exhaust. The adjustment is made by turning the upper rear spindle a.5, first removing its set screw under the pedal.
Turn clockwise to cushion Later.
Anti-clockwise to cushion earlier.
Take care that the front spring spindle a. 11 is not screwed too far into the valve, as otherwise its collar comes in contact with the end of the valve body before the valve reaches its seat, and cushioning cannot take place. The end of spring spindle should stand out beyond its steel guide piece a. 12 not less than 2 inches when rammer head is right back.
Cushioning in Withdrawal is effected by throttling the exhaust. First remove the guide cover a.8 from the lower front spindle a.9. Turn the spindle until the outer edge of the square nut on end of spindle is 445 inches from the front end of the valve body when rammer head is right back. Then try running the rammer part stroke and back again, noting that, in withdrawing, the speed should not be too slow as otherwise the rush of water is not sufficient to carry the shuttle valve a.3 into the neck of the throttle, and a blow on the rammer head ensues.
Adjust cushioning by turning the lower front spindle a.9
Clockwise to give later cushioning.
Anti-clockwise to cushion earlier.
Take care in adjusting that the spindle a.9 is not turned too many times anti-clockwise, as it is possible to adjust until the shuttle valve passes too far through the throttle neck, and a very early cushion is followed by a severe blow on the rammer head as the throttle is re-opened. The outer edge of the square nut should never stand further out from the valve than 4.5 inches.
Cordite Stroke.-The adjustments for cordite ramming should next be made, the stroke assumed being 7 feet 7 inches. If, in trying the rammer for cordite after all previous adjustments have been made, this stroke of 7 feet 7 inches is not obtained, it will be necessary to adjust the space of about .45 inch between the locking plate a. 10 on lower rear spindle and intercepting valve. This is done by turning the pinion H relative to the wheel J with which it gears.
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Increase the space if cordite stroke is too long.
Decrease if stroke is too short.
If the error of stroke should exceed 5 inches, an adjustment may first be tried, before disturbing the spiral pionion H by uncoupling the connecting rod F where it joins the screwed rod G, giving the latter one half turn, the direction depending, of course, on whether the space between the locking plate and valve is to be increased decreased.
Re-Adjustments Required.-Any adjustments made to length of cordite stroke affect all the adjustments made for cushioning, both for withdrawing, and for ramming light, and also for pressure throttling, and therefore all the processes previously described should be gone through again before trying rammer for cordite, otherwise some damage is likely to be done to the gear.
Speed of Cordite Ramming.-As the speed in ramming cordite should be less than that of ramming shell, a stop m. 1 is provided on control lever which limits the stroke of the working valve.
An easy method of adjusting this speed, without interfering with the above stop, is to alter the length of the connecting rod N between lever M and the working valve B by means of the adjusting nut provided. The speed for cordite ramming can in this way be greatly varied without appreciably affecting the speed of shell ramming.
Shorten rod if speed is too fast. Lengthen if too slow.
LUBRICATION.
See that rammer chain and intercepting valve details are all well lubricated.
CAUTIONS.
In making the various adjustments, it is necessary to see that one adjustment does not disturb another, e.g., if the upper rear spindle a.5 be not locked it is possible when turning the upper front spindle a. 11 to disturb the former and vice versa.
The same thing may occur on the two lov4er spindles a.4 and a.9.
VOICE PIPES.
PLATES 68 AND 69.
The voice pipes in the revolving structure are arranged in the usual manner and each turret is connected to the transmitting station. Further, in B turret, there is voice pipe communication to the conning tower.
ELECTRIC FIRING AND NIGHT SIGHT CIRCUITS.
PLATE 70.
There are two circuits viz: one main and one auxiliary, arranged in the following manner on each gun.
The Main firing circuit is connected with the firing keys which have smooth handles and is the one for general use.
The Auxiliary firing circuit is connected with the firing keys which have roughened handles, and is for use when the main circuit is out of order.
Each circuit is fed from its own Gun Circuit Box fitted in the turret.
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For the supply of current there are two Hydraulic Generators of the Pelton wheel type situated one on each side of the turntable in the pockets under the floor of the gun house as shown on Plate 2. Each generator is coupled through two Admiralty pattern No. 1072A Circuit Breakers with the gun circuit boxes. Two-way switches are fitted inside the gun circuit boxes to enable either hydraulic generator to be put in circuit as required. Interceptors are fitted in the circuits as usual.
The Night Sight cables from the main and auxiliary gun circuit boxes are connected to the night sight change-over-switch (Admiralty pattern 3742), and then to the night sight switches.
Fitted to each firing key is a Buzzer, which, being connected across the terminals indicates when the circuit is complete by giving out a humming sound.
The Auxiliary firing circuit is ordinarily connected to a dummy connection fitted on the end frame of the gun, and when the circuit is required for use the cable is disconnected from the dummy connection and fixed to the safety contacts on the breech mechanism, the main circuit cable having been previously taken from the breech contacts.
The main circuit cable is stowed in the dummy connection when the auxiliary circuit is in use.
A trainer's "Off" and "On" Switch is provided in the centre sighting position, and a change-over-switch in each side sighting position. These switches cut out the main and auxiliary firing keys, and allow the guns to be fired from the Director Firing station. The supply for the director firing circuits is led up the trunk.
Leads marked 30 and 57 are used when practising with Sub. Cal. Gun, and are connected between the interceptor and lock of Sub. Cal. Gun.
PERCUSSION FIRING GEAR.
The Percussion firing gear fitted is in the form of a lanyard carried on fairleads and operated by a lever situated near the side gun layers' positions.
LOCAL FIRE CONTROL.
The local fire control dynamo is driven by a hydraulic engine of the swashplate type, and is fitted in the working chamber as shown on Plates 2 and 4.
TURRET LIGHTING.
Turret Lighting is divided into three sections, viz.
(1). Primary lighting.
(2). Secondary lighting.
(3). Emergency lighting.
The primary lighting is supplied from the ship's mains 220 volt, and is led up the trunk to two distribution boxes fitted in the working chamber.
The secondary lighting consists of miners' lamps (accumulator type), oil lamps, and candle lamps.
Emergency lighting is fitted in each turret. This consists of 12-20 volt lamps on wandering leads to which current is supplied by two batteries of accumulators. pattern No. 4822, 6 lights off each accumulator. The charging board is fitted in the left hand training engine compartment.
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RANGEFINDER WINDOW CLEANING GEAR.
PLATE 72.
This plate shows the Air-and-Water device for cleaning the rangefinder windows. Air under pressure is led to a connection on the rangefinder by means of a pipe connected to the air blast system on the reduced pressure side of the R.H. reducing valve. Water to which soda or other solvent has been added is supplied by means of a hand pump from a reservoir in the officers' screened in structure, and a pipe led to a connection on the rangefinder.
From the connections on the rangefinder, which are referred to above, the air and water services are led to nozzles at the windows by means of pipes inside, and forming component parts of the rangefinder supply.
Included in the rangefinder supply there is provided a desiccating plant with a hand pump and flexible pipes. The pipes are fitted to the rangefinder in each turret, but there is only one hand pump, etc., per ship.
LUBRICATORS.
PLATES 73, 74, AND 75.
These plates show the Principal lubricators in gun house, working chamber, and trunk. There are besides various oil holes in bearings, rods, etc., which cannot be indicated in the diagrams, but which at the same time are important, and which require attention.
DIRECTOR FIRING GEAR.
PLATES 71, 76, 77, AND 78.
Included in this handbook, there are, in connection with Director Firing Gear, four plates, which are intended for purposes of general information, and are as follows:-
71. Open director sight in gun house. This sight is fully described and illustrated in the Director Firing Handbook.
76. This shows diagrammatically the arrangement of training and training control gear for the revolving hood over conning tower.
77. This plate shows a complete arrangement of the aloft director tower and gear with diagrammatic arrangement and description of control gear, and
78. Shows, in elevation and section, the variable speed gear used in the aloft director tower, and indicated on Plate 77. This variable speed gear is of the Williams-Janney type and is built on the usual and well-known standard lines.
LIFTING JACKS FOR GUN SLIDE.
Hydraulic Jacks are provided for lifting the gun slide to allow of the trunnion pins being withdrawn and examined. They are shown on Plates 1 and 2. The jacks are operated by a Hand Pump placed in the centre girder of the turntable under the trunnions. Stop valves are arranged on the pipes from the hand pump to the lifting jacks to enable either gun to be lifted independently of the other. Special packing pieces for fitting between jacks and slides are provided.
After having been raised the gun may be lowered by opening a release plug on the hand pump; this allows the pressure water to flow back into the pump suction tank.
An hydraulic pressure gauge is provided near the pump to indicate when the weight of the gun, etc., is on the lifting jacks.
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CORDITE DRENCHER.
A set of gear is provided for Drenching the Cordite in the auxiliary cordite buckets in case of fire. Water is supplied from the main ring pressure pipe in the working chamber, the supply pipes being in duplicate with a stop valve on each pipe next main ring. One of these valves, marked "Master Valve to Cordite Drencher," is padlocked in the open position to ensure that on opening the stop valve at the other end of the pipe, i.e., in the magazine, the drencher comes into action. The drencher can also be turned on by opening the valve in the working chamber marked "Valve for Drowning Cordite Charges." The spray pipe is fitted in the trunk and serves for cage in the bottom position only.
FIRE SERVICE.
A flexible hose is provided for Fire Service, and is stowed in the auxiliary cordite compartment of the gun shield as shown on Plate 3. The supply pipe is taken off the main ring pressure pipe in the working chamber, and has a stop valve at each end. The flexible hose is permanently connected to the supply pipe and has a stop valve at the nozzle.
Note- This document is not yet complete. We plan to add the remainder as time permits.