Gun Traverse Apparatus

1. Technical Field

This invention pertains to gun mounts for weapons and, in particular, gun mounts for providing additional traverse capability independent of the carrier upon which the gun is mounted.

2. Background Art

In recent years, self-propelled guns have been developed that do not employ a rotating turret. These vehicles traverse the guns by turning the entire vehicle on its tracks. This is done by utilizing the hydrostatic, infinitely variable steering system in the automotive transmission. These weapons, however, have the disadvantage of having only a limited range of traverse where the terrain conditions are difficult to maneuver. Furthermore, they can dig themselves into a hole if firing numerous rounds from a single position.

Techniques have been developed to give the gun a traverse independent of the position of the vehicle. Typical of these devices are spherical balls, the conventional turret, and a U-gimbaled mount for the gun. All of these mechanisms have various problems, in some cases being very heavy, and in the case of the U-joint gimbal, lacking the ability to transfer the reaction force upon firing a round directly to the trunnions which support the gun on the carrier.

It is an object of this invention to provide a limited traverse capability to the gun relative to the carrier of the gun for increasing the field of fire available to the weapon.

It is another object of this invention to provide a traverse apparatus which transfers the reaction load upon firing a round directly to the trunnions which support the gun.

It is another object of this invention to provide a simple, lightweight gun traverse apparatus for traversing the gun relative to the carrier.

Basically, these objects are obtained by mounting the gun trunnions in eccentrics which can be simultaneously pivoted in opposite directions to slew or traverse the gun relative to the carrier upon which the trunnions are mounted. In the case of a mobile carrier, the position of the gun as traversed by the eccentrics will signal to the hydrostatic steering system in the transmission to change the carrier position when the traverse from the eccentric trunnions is reaching the limits of its capability. The apparatus is very lightweight since it takes advantage of the use of the readily available trunnion elevation mounting members and adds little additional structure which would increase the weight of the weapon.

FIG. 1 is a schematic illustration of a gun traverse apparatus embodying the principles of the invention.

FIG. 1A is a detail of a valve used in the control system for the traverse apparatus.

FIG. 2 is a fragmentary transverse section through a portion of the carrier embodying the principles of the invention.

FIG. 3 is a schematic illustration of a steering system control for mobile carriers embodying the invention.

As best shown in FIG. 1, a gun 10 is mounted on a carrier 11 of any conventional kind, such as a Swedish S-tank or the West German casement tank, which are typical. The gun could also be mounted on an immobile carrier.

The gun is provided with trunnions or pivots 12 and 14 each of which is secured to the carrier so the gun can be rotated about a common gun axis GA. The trunnions are each rotatably mounted in bearings 16 and are essentially identical. Accordingly, the details of only one trunnion and its mounting will be described.

An eccentric 18 includes an eccentric plate 20 which is mounted in an outside bearing 22. The center of rotation of the eccentric plate is about an eccentric axis EA which is offset from the gun axis GA. The eccentric axis of each trunnion is offset equally in the same direction, and thus the axes are aligned with one another. The outer race of the bearing 22 is mounted in a housing 24 which is fixed to the frame of the carrier. The eccentric plate 20 is then coupled to an eccentric arm 26.

The gun axis lies below the eccentric axis. When the eccentric arm of each eccentric is rotated in equal but opposite directions, the eccentrically between the two axes EA and GA causes the gun to traverse or skew in a horizontal direction. The traverse capability is about five degrees in each direction, giving a ten degree range of traverse relative to the carrier, which equates to approximately 52 seconds of tracking a crossing target, traveling 30 miles an hour at a distance of 4,000 meters.

The eccentric axes could be offset in opposite directions if desired and suitable control changes were made to accommodate the different motions required to produce skewing of the trunnions. Cylinders 70 provide vertical positioning of the gun 10 in a conventional manner.

The control system for operating the eccentric arms is best shown in FIG. 1 and includes an actuator or cylinder 30 and an actuator or cylinder 32. The actuator 30 has a piston rod 30a and piston 30b coupled to eccentric arm 27, whereas the other actuator has a piston rod 32a and piston 32b coupled to the other eccentric arm 26. A traverse control valve 34 is a three-position valve having a line 36 which connects to a one-way lock valve 38 and a line 37 which connects to a second one-way lock valve 39. The lock valves are conventional and are operated from pilot pressure lines 40 and 41. Shifting of the traverse control valve in one direction will introduce fluid through line 36 through the flow control valve 38 to the actuator 32 to rotate the eccentric arm 26 in a counterclockwise direction. The fluid in the opposite rod end of the actuator flows out of actuator 32 through a common line 42 to the rod end of the actuator 30. This drives the eccentric arm 27 in a clockwise direction, as viewed in FIG. 1, that is, in a reverse direction to eccentric arm 26. Fluid in the head end of the actuator 30 flows through the flow control valve 39, which does not open until the pressure in pilot line 40 exceeds a desired amount so that the eccentrics must always be operated against a back pressure or a power-driven mode.

Preferably, the recoil force of the round on the gun 10 will be transferred directly to the trunnion and thus to the frame via the bearings 16 and 22. This advantageously reduces the amount and size of structure otherwise necessary to transmit the recoil force to the frame. Since the gun axis is below the eccentric axis, the recoil force on the trunnions will cause both eccentric arms to attempt to pivot counterclockwise. The control circuit, as shown, is arranged to transfer this force to the rod ends of the actuators. This in effect dead-ends the fluid flow so that the force reacts against rigid piston rods due to the incompressibility of the fluid. As an alternative, the eccentric and gun axes could be reversed in their relative positions and the lines from the control valve located at the rod ends of the actuators.

In order to initially synchronize or align the relative positions of the pistons within their actuators 30 and 32, at least one, but preferably two, synchronizing valve 50 are positioned in the pistons. A typical synchronizing valve is shown in FIG. 1A and includes, as an example, valves 56 and 57 pushed closed by a central spring 54. In operation, when the first piston bottoms out in either direction prior to the piston in the opposite actuator, one of the rods 56 or 57 is depressed, allowing flow to pass through the piston until the opposite piston rod also bottoms out. In this condition then, both of the pistons are in alignment with one another but at opposite ends of their respective actuators and henceforth will operate in synchronism with one another.

While the apparatus above-described is also suitable for stationary carriers, it is best suited and most advantageously employed for mobile carriers, preferably of the type in which steering of the vehicle is through a conventional hydrostatic steering system 60 (FIG. 3). The steering system 60 controls the automotive transmission for controlling the tracks of the vehicle. It is understood, of course, that traversing by the above-described traverse apparatus is limited in distance to about ten degrees full traverse. Thus, as the target begins to leave the traverse capability of the trunnion traverse system, a signal is given to the hydrostatic steering system 60 to reposition the carrier so that it brings the gun back into the eccentric traverse capability. This signal can be accomplished several ways, either mechanically, hydraulically, or electrically. A preferred mechanical configuration is best shown schematically in FIG. 3 and includes a link 62 which is coupled to an eccentric arm and to a valve operator 64 in the steering system. Another rod 66 is connected to the driver-operated steering input station 68 for manually overriding the automatic system. Thus, as is well understood, by movement of the gun in traverse to its limit, the link 62 then signals through the valve operator 64 to the transmission to begin a turn of the carrier in that same direction.

While the preferred embodiment of the invention has been illustrated and described, it should be understood that variations will be apparent to one skilled in the art without departing from the principles described herein. Accordingly, the invention is not to be limited to the specific embodiment illustrated in the drawings.