FIELD OF THE INVENTION

THIS invention relates to a mechanism for loading an artillery gun or the like,

more particularly for emplacement of a combustible charge within the

combustion chamber of the breech of the gun.

5 BACKGROUND OF THE STATE OF THE ART RELATING

TO THE INVENTION

Conventionally the combustible charge is manually placed within the breech

of an artillery gun during the loading process. Such manual loading has

several disadvantages including the following:

10 (i) such systems have a relatively long firing cycle that does not

allow for high firing rates;

(ii) large charges are difficult to handle manually, especially in the

confined space of a turret;

(iii) ergonomically it is difficult and dangerous to place the charge

15 manually inside a barrel chamber which has an automatic sliding

breech;

(iv) possible misplacement of the charge within the breech; and

(v) the dangerous environment inherent in the manual handling of

explosive charges.

OBJECT OF THE INVENTION

It is accordingly an object of the present invention to provide a novel loading

mechanism for transferring an explosive charge from an exterior position to

a position within the combustion chamber of the breed of an artillery gun or

the like. It is a further object to move the aforesaid charge from a position

exterior the breech the within the combustion chamber in an uninterrupted

movement. Yet a further object of the invention is to move a charge in an

axial direction into a predetermined position within the combustion chamber

of the breech and thereafter at a terminal zone to impart a transverse

component of movement to the charge for locating purposes.

SUMMARY OF THE INVENTION

Thus according to the invention a loading mechanism for placing a combustible

charge in a predetermined position within the breech of an artillery gun or the

like includes an elongated cradle structure which is adapted to receive the

charge, and to be axially aligned with the breech; and a plunger device

coupled to a lever arrangement so that pivotal movement of the lever

arrangement positions the plunger device behind a charge located in the cradle

structure and causes the plunger device to displace the charge axially along the

cradle formation into the combustion chamber of the breech.

Further according to the invention the loading mechanism includes a shoe

member movable along the cradle structure and drive means for such shoe

member, the arrangement being one wherein the shoe member is adapted to

engage behind a charge in the cradle structure to move such charge for a

predetermined initial distance whereafter the plunger device will move the

charge for the remainder of its travel to a position within the breech.

Preferably the drive means will cause the shoe member to travel the pre¬

determined initial distance and thereafter engage the lever arrangement of the

plunger device to cause movement thereof. The drive means could for

example comprise a rotating threaded shaft, a moving chain, a fluid operable

ram or other drive actuator. Preferably a pair of such drive means adapted to

act in unison, will be provided.

Still further according to the invention the lever arrangement of the plunger

device comprises a telescoping lever arm which decreases and increases its

effective length in order to maintain the plunger device in substantial axial

alignment with the charge during movement thereof. In a preferred

arrangement the lever arrangement will comprise a pair of parallel lever arms

which form a pantograph-type system, each lever arm being of a telescopic-

type as described above. Preferably also two pairs of parallel lever arms as

above will be provided.

It is envisaged that telescopic movement of the lever arms will be controlled

by means of a guide and follower-type system. Thus for example a follower

in the form of a roller could be mounted on a movable portion of the lever

arm, such follower co-operating with a guide track so as to control telescopic

o movement of the lever arm during pivotal movement thereof.

It is a further feature of the invention that the charge will be given a transverse

component of movement once it is fully located within the bieech and the

invention provides that the guide and follower system will cause this effect by

a suitable profile for the guide.

5 Also included within the scope of the invention is a method of loading a

combustible charge into the breech of an artillery gun or the like comprising

the steps of locating the charge in a cradle structure, axially aligning the latter

with the breech, moving the charge towards the breech by means of a shoe

formation which is axially movable relative to the cradle structure, moving a

plunger device which is coupled to a pivotally movable lever mechanism into

position behind the charge and continuing the movement of the charge by

means of the plunger device to a position wherein the charge is fully located

5 within the breech.

Further according to this aspect of the invention the shoe member and plunger

device are sequentially driven by the same drive mechanism. With such an

arrangement the drive mechanism will preferably be decelerated as the plunger

device moves into contact with the charge in order to provide an uninterrupted

l o continuous movement of the charge.

Still further according to the invention the method includes the step of

imparting a transverse, preferably downward component of movement to the

charge as it is fully inserted into the breech. It is envisaged that such

downward component of movement will locate the charge behind a retaining

15 shoulder within the breech.

DESCRDTΠON OF THE DRAWINGS

Further features of the invention will appear from the preferred embodiment

which is described below purely by way of example with reference to the

accompanying drawings wherein :

5 Figure 1 is a schematic perspective view of a loading mechanism

for placing a combustible charge within the breech of an

artillery piece in accordance with the invention;

Figure 2 is a schematic elevation of the loading mechanism in

Figure 1;

_l o Figure 3 is a schematic end elevation of the loading mechanism in

Figure 1;

Figures 4 to 6 are schematic representations of the operation of the

mechanism in Figure 1 during the process of inserting a

charge into the breech of an artillery piece; and

Figure 7 is a graph giving a schematic illustration of the

components of movement of a plunger device of the

mechanism in Figure 1.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring to the drawings a mechanism for loading a combustible charge 13

into the breech combustion chamber 10 of an artillery gun or the like

comprises a housing 11 which defines an elongated cradle structure 12 at its

upper end. The length of the cradle structure 12 is sufficient to receive a full

charge 13 therein. It is a feature of the invention that partial charges of lesser

length than a full charge 13 can also be located in the cradle 12 for loading

purposes. In order to prevent a charge 13 from becoming dislodged at high

elevations of the loading mechanism, pivotal locking fingers 14 are provided

as shown in Figure 3. The locking fingers 14 are pivotally displaceable to a

retracted position wherein they are disposed outside of the interior space of the

cradle structure 12 to permit the charge to be located therein; and a locked

position wherein the finger elements 14 are directed into the interior space of

the cradle structure 12 to hold the charge 13 in position as shown in Figure 2.

Means for axially moving a charge 13 from the cradle structure 12 into the

breech 10 comprises a shoe member 14 movable from the remote end of the

cradle structure 12 towards the front end thereof. In the arrangement

illustrated the shoe member 14 is coupled by means of a ball screws 15 or the

like to a pair of parallel rotatable threaded rods 16 so that synchronous rotation

of the threaded rods 16 will positively drive the shoe member 14 along the

length of the cradle structure 12. With reference to Figure 2, the threaded

rods are driven by means of a drive motor shown schematically at 17 and

drive chain 18. In an alternative arrangement, not shown, the threaded rods

16 could be replaced with an endless articulated chain or the like, and

doubtless other variations are also possible.

It is a feature of the invention that a plunger device 19 is provided to move the

charge 13 beyond the extent of the cradle structure 12 into the breech 10 of

a gun. Such plunger device 19 comprises a stem 19a and second shoe

formation 19b mounted at the end of a pair of parallelly disposed lever arms.

The lever arms have their respective fulcrums at 20a and the effort on the

lever arms is applied at 20b in the nature of a third degree lever which thus

results in a distance multiplication effect.

The parallel lever arm arrangement acts to maintain the stem 19a parallel to

the axis of the cradle structure 12 during pivotal movement of the lever arm

members 20. For purposes of stability two pairs of parallel lever arms 20 are

preferably provided each pair operated by one of the threaded rods 16 as

5 explained in more detail below.

The arrangement is further characterised in that the lever arms 20 are of a

telescopic construction to enable the arms 20 to be shortened or lengthened as

required to cause the plunger device 19 to follow a predetermined pathway

during operation thereof. In the arrangement illustrated the plunger device 19

o upon activation firstly moves in an arc into a position wherein the stem and

shoe 19a, 19b are disposed within the interior of the cradle structure 12,

behind the charge 13, Figure 4. Thereafter the plunger device 19 moves along

or parallel to the axis of the cradle structure 12, Figure 5. Finally, the

plunger device 19 will, at the end of its stroke, perform a transverse

5 downward movement, in order to impart a transverse movement to the charge

13 for purposes of locating the latter behind a retaining collar 10a in the

breech 10. The telescopic movement of the lever arms 20 is controlled by

means of rollers 21 located on a movable portion of each telescoping arm 20,

such rollers 21 co-operating with guides 22 to shorten or lengthen the effective

length of the arms 20. Thus for the sequence of movements described above,

the length of the lever arms 20 will remain unchanged up to the position

shown in Figure 4 and graphically at AB in Figure 7. Thereafter the length

of the lever arms 20 will be shortened and then lengthened as the lever arms

5 20 rotate, in order to maintain the plunger device 19 on the axis of the cradle

structure 12 as shown at BC, Figure 7. Finally, towards the end of the pivotal

movement of the lever arms 20, the guides 22 will cause the lever arms 20 to

be shortened in order to impart a transverse movement to the plunger device

19 and to the charge 13 as shown at CD, Figure 7.

l o Pivotal movement of the lever arms 20 is effected by a pull rods 23 with one

such pull rod 23 extending from each pair of parallel lever arms 20 to a bush

24 each of which is slidably mounted on the rotating threaded rod 16, the

arrangement being such that as the ball screws 15 advance along the threaded

rods 16, they each engage a sleeve 24 to cause movement thereof and

15 consequently movement of the pull rods 23.

It will be appreciated that the distance which the sleeve 24 travels will be

multiplied by the action of the third degree levers 20 so that the plunger device

19 will move to a position beyond the front end of the rotating threaded rod

16. This distance multiplying effect has the result that linear movement of the

ball screws 15 through a distance of 1.1 meters, will displace the combustible

charge 13 through a distance of approximately 1.5 meters into position within

the breech. Moreover the shoes 14 and 19b are both positively located and

driven to ensure that the combustible charge 13 is positively displaced and

located in a predetermined position within the breech 10.

It is also a feature of the invention that the combustible charge 13 will be

loaded into the breech 10 in an uninterrupted sequence and at a substantially

constant velocity. The method of loading is accordingly characterised in that

the plunger device 19 is decelerated as it moves into position behind the charge

13. Such deceleration will be effected by decelerating the drive motor 17 to

the appropriate revolutions.

Doubtless variations of the invention exist without departing from the

principles set out in the consistory clauses.