GPO Vehicles

P.O. ENGINEERING DEPT.
ENGINEERING INSTRUCTIONS
MOTOR TRANSPORT
TOOLS & TRANSPORT
VEHICLES
B 3856
Issue 1 (20.1.66)

The 6-ton Articulated Cable Drum Carrier, Type 1

1. General
This Instruction describes the 6 Ton Cable Drum Carrier Type 1 (Morris) and the procedures to be observed in its operation.  It is interchangeable with the 6 Ton Drop-frame Articulated Trailer used for the cartage of cable drums.

DESCRIPTION

2. General description and facilities
The vehicle is an articulated unit comprising a 15 ton forward control prime mover (with seats for two men) coupled to a straddle frame trailer.  A dual purpose load carrying assembly is mounted within the trailer framework and is raised or lowered by two hydraulic rams via a system of levers.  This assembly consists of four columns of cable drum spindle hooks supporting, at the bottom, a frame for a removable floor.  It provides facilities for the carriage and hydraulic lifting of:-

1. Two large cable drums of up to 7 ft. 6 in. in dia.

2. A limited general load.

3. Poles.

3. Data Summary
Table 1 gives details of dimensions and loading.

Table 1

Fig. 2

4. Cable drum spindle hooks
There are six spindle hooks in each column (Fig. 2) the hooks being spaced at discrete intervals consistent with the range of drum sizes to be handled.  As the column is raised, locking tongues automatically come down to trap the spindle (Fig. 3) but, should the columns have to be partly raised to allow a drum spindle to register with a pair of hooks, the locking tongues can be levered upwards sufficiently to clear the hook entries. The spindle restrained horizontally by plates on the outside of the columns of hooks (fig 3).

Fig. 3

5. Removable floor
When not in use the floor sections and tailboard are stowed on the raised section of the trailer.  To bring the floor area into use, the sections are simply dropped into position in the floor frame and the tailboard hinge pins located in the pin housings at the rear of the frame; the floor sections are equipped with 'budget locks' on either side and these locks MUST always be locked when the floor sections are in position (see fig 2).

6. Hydraulic system
A power takeoff from the vehicle gearbox is used to drive a hydraulic pump which supplies the power to actuate double acting rams on the trailer. The hydraulic systems of the trailer and vehicle are connected via flexible pressure hoses incorporating self-sealing couplings. Two mechanically-coupled levers (Fig. 4) control the valves regulating the circulation of hydraulic fluid.

7. Mechanica1 lock
To ensure the security of a load in transit, an over-riding automatic mechanical lock is applied to the trailer's hydraulic system when it is fully raised. This comprises a trailing arm (Fig. 5) on each lever system, which latches behind abutments on the trailer framework as the rams near the top of their travel.  A lever system on the front of the trailer (Fig. 4) actuates plungers which will raise the bottoms of the trailing arms above abutment level when the rams take the strain, so releasing the mechanical lock.

Fig. 4

8. Hydraulic ram coupling
Synchronization of the hydraulic rams is achieved by linking the pivots of the levers immediately connected to the rams, using a heavy tubular member (Fig. 5).  This tubular member is in two sections which are linked by a sleeve and brass shear pin, so that if the lever system on one side jams, the fuse will break, preventing the coupling member being permanently distorted and giving the operator an urgent audible alarm.  The operator must immediately move his control lever to NEUTRAL on hearing the sharp crack of the breaking of the shear bin, otherwise permanent damage to the vehicle will be caused.  The shear pin must be replaced before this control is re-operated.

Fig. 5

9. Auxiliary equipment
The miscellaneous equipment provided with each trailer is listed in Table 2. See also Fig. 6.

TABLE 2

Fig. 6

10. Carriage of poles
A fixed front bolster with tall side horns is fitted on the front raised platform of the trailers.  The rearmost cable drum spindle placed in the topmost pair of hooks functions as a rear bolster bar.  Poles up to 30 ft. in length can be carried; the number will depend on pole diameter, shape etc.

11. Maximum load
The maximum load that can be carried on the articulated trailer is 6 tons.  If the load comprises cable drums the heaviest drum that may be
carried is 4 tons and this must be carried in the forward position as should the heavier of any pair of drums carried.  A simple check of the loading of the vehicle can be made by weighing the complete unit or the trailer in the fully laden condition; these laden weights should not exceed the maxima quoted in Table 1. Any weighbridge charges involved should be passed to 'Freight and Cartage'.

12. Tool locker
A locker is provided on the near-side of the trailer.  This will accommodate trailer tools, vehicle tools, chain hoist and other small auxiliary equipment.

13. Locking
The driver's door can be locked with a standard '750 code' key, the near-side door is secured by moving the inside door handle in the reverse direction to that for opening. An individual barrel lock is fitted to the near-side locker.

14. Trailer spare wheel
Because of space restriction the trailer spare wheel has been mounted above the near-side catwalk and on a vertical stand.  It is located on two threaded studs and secured in position by two wheel nuts plus a clamping bar.  Always ensure that both the wheel nuts and the clamping bar are firmly tightened when replacing the spare wheel on its stand.

15. Rear lights
The obligatory rear light assemblies are of a quick release removable type so that they can be quickly transferred from the trailer to the motive unit when the motive unit is uncoupled.  An extension rear light is provided for use with overhanging loads (see M 0027).

OPERATING INSTRUCTIONS

16. Motive unit Uncoupling
To uncouple the motive unit from the trailer the following procedure should be observed.

1. Ensure that the ground under the trailer is not uneven, cambered or Such conditions might make it impossible to re-couple.

2. Apply the parking brake on the trailer and ensure that PTQLcor lever in the motive unit (Fig. 7) is in the OFF posit

3. Check that the hydraulic hoses are uncoupled from the motive unit.

4. Uncouple the anti-jack-knife device from the trailer and couple it to the storage pin provided on the motive unit.

5. Lift the safety catch in the cab and squeeze the trigger (fig 7).

6. Engage first gear cab and drive out slowly.

7. Remove the detachable rear light fitments from the trailer by depressing the spring loaded lever and sliding a fitment off its plate mounting.

8. Fit the rear light fitments on the plate mountings at the rear of the motive unit.

9. Move the trailer number plate to the motive unit.

[WARNING. Do not allow inexperienced persons to tamper with the trailer undercarriage when the trailer is uncoupled unless it is supported on trestles at its front end, as disturbances of the safety catch may cause collapse of the undercarriage with serious consequences]

Fig. 7

17. Coupling
Essentially the process for re-coupling trailer and motive unit is the reverse of the uncoupling procedure.

1. Move rear number plate and detachable rear light fitments from the motive unit to the trailer.

2. Check that the parking brake on the trailer is firmly applied and that the corresponding lever in the motive cab is in the OFF position.

3. Reverse the motive unit into position in front of the trailer stopping with the ramp some 8in. from, and lined up with the flanged rollers on the trailer.

4. Reverse slowly for the final 2 ft. required to engage the trailer completely.

5. Observe that the coupling warning light mounted on the dashboard flashes once as step (d) is executed.  If the light remains on, coupling has only been partially achieved, in which event the cause should be investigated and the motive unit disengaged and re-engaged.

6. Remove the anti-jack-knife device from its stowage pin and re-couple it to the trailer.

7. Check that the safety catch of the trailer release trigger is secure.

8. Release the parking brake on the trailer.

NOTE:- The trailer hand brake lever located in the cab (Fig. 7) is for the purpose of gradual application of the trailer brakes during wet and icy conditions.

18. Load carrying carriage
Procedure for lowering.

1. Connect both hydraulic hoses.  Screw down the couplings tightly to ensure that the oil sealing valves are unsealed.  Failure to do this will result in the hydraulic gear failing to operate.

2. Check that the hydraulic control lever is in the neutral (central) position.

3. Start the vehicle engine.

4. Engage the power take-off/hydraulic pump.  A pilot light on the dashboard is illuminated while the power take-off is engaged.

5. Move the hydraulic control lever to LIFT until both locking sprags clear the abutments.

6. Release the mechanical lock.

7. Check that both sprags are above the top of the abutments.

8. Move the hydraulic control lever to LOWER.
    

19 Procedure for raising

1. Repeat steps 18(a) to (d).

2. Move the hydraulic control lever to LIFT until both locking sprags have slipped over the abutments.

3. Move the hydraulic control lever to LOWER until both locking sprags are properly registered against the abutments.

20. Before moving the vehicle ensure that:-

1. The power take-off/hydraulic pump is disengaged.

2. The hydraulic hoses are uncoupled.

21 Cable drums
Preparing to load.
Before proceeding to load cable drums, attention should be paid to the following points.

1. The maximum permissible drum weights quoted in para. 11 must not be exceeded.

2. The heavier drum of the pair to be loaded must occupy the forward position.

3. As far a possible drums of the same size should be prepared for convenience in loading.

4. A few spare drum battens should be to hand.

5. The loading operation should be carried out on even and reasonably level ground.

6. A drum slewing tool should be available.

7. The advice given in GENERAL, General, Z 1020, on the manual handling of cable drums should be observed.

22. Loading

1. Lower the load carrying carriage (par. 18).

2. Remove the drum spindles from the spindle hooks.

3. Line-up the first drum to be loaded at the rear of the trailer so that it can be rolled down the centre of the straddle frame.

4. Roll the drum forward until the spindle hole is past the first columns of spindle hooks.

5. Insert a drum spindle into the drum; the eye pin provided will fit into a hole in the end of the spindle to facilitate manoeuvring the spindle into position.

6. Thread a spindle collar on either side of the drum and secure them hand tight.

7. Roll the drum forward until the spindle is against the forward column of spindle hooks; note the height of the spindle ends in respect of the appropriate pair of spindle hooks.

8. If the spindle level is no more than 1 in. below a pair of hooks, or one side is somewhat lower than the other, roll the drum back to allow spare battens to be put down to pack-up the drum appropriately.

9. Roll the drum forward again to the position in (g) and if the spindle level is correct, centre the spindle accurately, secure the collars against the drum flanges and push the drum firmly home.

10. Chock the drum securely to ensure that it is not moved by operations on the second drum.

11. If the spindle level noted under (g) is outside the limit mentioned, raise the carriage sufficiently to bring the set of hooks immediately below the spindle into line with the spindle, the locking tongue being levered clear if necessary, and proceed as in (l) and (m).  If the two drums being loaded are not of the same size, it is important to ensure that the front drum gets the maximum lift possible so that the rear drum has adequate ground clearance when fully raised.

12. Load the second cable drum on  the rearmost cable hooks using the same procedure as for the first drum.

13. Check that the spindle ends are all properly located on their respective hooks.

14. Raise the load carrying carriage as in para. 19.

15. Fit and tighten anti-rotation straps; fit at least two battens temporarily on an unbattened drum to give a bearing surface.

16. Disengage the power take-off/hydraulic pump.

17. Uncouple and stow the hydraulic hoses.

18. Recover and stow the chocks (Fig. 5) and any spare drum battens; note the amount of any packing used.

23. Unloading

1. (a) Remove anti-rotation straps and any temporary battens.

2. Lower the load carrying carriage (par. 18) until one drum (or both) just touches the ground.

3. Place in position any levelling packing necessary below a drum.

4. Chock the drums securely to ensure that they cannot roll clear of the hooks and out of control.

5. Complete the lowering of the carriage.

6. Remove the chocks in turn and roll each drum clear.

7. Recover any temporary packing battens used.

24. Poles. Loading

1. Lower the load carrying carriage (par. 18).

2. Place the rearmost cable drum spindle in top position.

3. Load the poles over the rear bolster and on to the bolster system using orthodox manual handling techniques.

4. Pole heads should not normally project beyond the front of the trailer but, with the longer poles, a projection of approximately 2 ft. will be necessary to ensure that the pole is advanced over the point of balance.

5. Temporarily lash poles during loading stages to prevent poles slipping back if they are greasy or if the ground slopes.

6. Temporarily lash the rear of the completed load prior to (g).

7. Raise the load carrying carriage (par. 19).

8. With a single layer of poles, lash the poles to the bolster bars as depicted in Fig. 8.  A staple hammered into each pole so as to straddle of the sash line will ensure that greasy poles do not slip back in tarnsit.

9. With multiple layers of poles arranged pyramid formation the two chain pullers are used for lashing.  D shackles are bolted to each of four anchorages welded to the trailer framing at the sides of of each bolster position.  The chain puller hooks are engaged on the respective D shackles and the chains firmly tightened.  Fig 9 shows a pole secured by chain pullers.

10. Fix overhanging marker at the rear of the pole load.

11. Prepare to move off as in para.20

Fig. 8

25 Unloading.. This is a simple reversal of the loading procedure.

Fig. 9

26. Spare wheel. Lowering

1. Unclamp the jib stowed under the off-side catwalk.

2. Mount the jib in the socket provided forward of the spare wheel and the near-side catwalk.

3. Attach the chain pulley block unit to the jib hook and raise the lifting hook to within 1 ft. of its maximum upward travel.

4. Unclamp the spare wheel.

5. Pass the 3 ft. chain sling provided through the centre of the spare wheel and engage both rings on the lifting hook.

6. Raise the pulley system until the spare wheel clears its seating and the jib can be swung outwards.

7. Lower the spare wheel to the ground (Fig. 10).

Fig. 10

27. Stowing
The procedure for replacing the spare wheel on its stand is a straightforward reversal of the unloading process.

28. Periodic testing of loading jib. See Mechanical Aids, J 1060. MISCELLANEOUS

29. Care of auxiliary items
Periodic inspections of the auxiliary items stowed in the vehicle tool box (see Fig. 6) should be made and any necessary repairs carried out promptly. Chains etc. should be wiped over with an oil rag to combat rusting. The two ratchet chain pullers, the spare wheel block and tackle and the spare wheel sling should be treated in accordance with Mechanical Aids, B 1007.

30. Signwriting
Standard inscriptions for signwriting are given in C 0015.

31. Damage to paintwork
Attempts to retouch any scratched or damaged parts should not be made by staff using the vehicle. Work of this nature is undertaken by the Workshop Supervisor/Mechanic-in-Charge when necessary and during periodic overhauls.

32. Speed limit
See D 0022.

 

Last revised: February 07, 2021