Patent Description:
In particular the disclosure is concerned with a towed howitzer system comprising a wheel arm of the present disclosure.

<CIT> is directed to a towed field gun with a moveable wheel arm. <CIT> is directed to a towed wheel gun.

A howitzer is a type of artillery weapon characterized by a cannon which can fire from low to high angle of elevation and traverse, and the use of propellant charges to propel projectiles. Commonly it is provided on wheels so it may be towed by a vehicle and thus transported to where required. An example of this equipment is illustrated in <FIG>.

In such a towed artillery system the suspension system is "leading arm suspension system". Each wheel <NUM> is held in front of a suspension pivot point <NUM> by a wheel arm <NUM>. To tow the platform, pressure is added to suspension struts which force wheel arms <NUM> to rotate downwards, thereby lifting the chassis of the gun off the ground into a towing configuration (as shown in <FIG>). The pressure can be added to the suspension strut by way of a manual pump to pump fluid into a suspension strut fluid chamber. The manual pump uses a long bar (known as a pump handle) as a lever arm to manually drive the pump. When the pump is not being used the bar is stored on the howitzer chassis.

To deploy the weapon, fluid is released from the suspension struts which allows the wheel arms to rotate upwards, lowering the platform onto the ground (i.e. moving the arrangement from that shown in <FIG>). To achieve full operability the wheels must be "thrown-over", which involves disconnecting the suspension strut and lifting the wheel up out of the way. By passing the balance point the wheel is retained in the elevated position by gravity. This position is shown in <FIG>, which is a firing configuration (i.e. the configuration in which the weapon is fully operational). It is also necessary to throw-over the wheels before some maintenance tasks on the brake system to allow access. With the wheels pivoted free of the ground, support legs <NUM> (if present) may be folded from their storage position (in <FIG>) to their deployed position (in <FIG>).

However, a problem with this arrangement is that because the wheel and associated components (e.g. brakes and axels) are heavy, Health and Safety Guidelines require that the operation is a two person lift, the act of which is illustrated in <FIG>. The wheel is a large, round, awkward object which is frequently wet/muddy. Therefore throwing-over the wheel can be dangerous for the users and in muddy conditions can be very difficult to achieve, and may result in injury and/or the weapon not being able to be operated to its full capability if the wheel cannot be pivoted to the correct position in time.

Hence a solution which enables the wheels to be moved between the towing configuration and firing configuration, and back again, which reduces risk to the user and increases the chances of a successful deployment regardless of the conditions, is highly desirable.

According to the present disclosure there is provided a wheel arm and a towed howitzer system as set forth in the appended claims.

Accordingly there may be provided a wheel arm (<NUM>) for a chassis (<NUM>) of a towed howitzer system (<NUM>), as defined in claim <NUM>.

The lever engagement feature (<NUM>) is provided as a protrusion (<NUM>) which extends away from the wheel arm (<NUM>) along an engagement feature axis (<NUM>).

A line (A-A) may extend between the arm pivoting axis (<NUM>) and wheel rotation axis (<NUM>) to define a longitudinal axis (<NUM>) of the wheel arm (<NUM>). The engagement feature axis (<NUM>) may be aligned with, parallel to, or at an angle "B" to the longitudinal axis (<NUM>).

The protrusion (<NUM>) comprises a wall (<NUM>) which defines a cavity (<NUM>), with an opening (<NUM>) centred on the engagement feature axis (<NUM>) and the drain aperture (<NUM>) extends through the wall (<NUM>).

A plurality of drain apertures (<NUM>) may extend through the wall (<NUM>).

The lever engagement feature (<NUM>) may be provided as a cavity (<NUM>) which extends into the wheel arm (<NUM>). The cavity (<NUM>) may extend along an engagement feature axis (<NUM>).

There may also be provided a towed howitzer system (<NUM>) comprising a wheel arm (<NUM>) according to the present disclosure, a chassis (<NUM>), wherein the wheel arm (<NUM>) is pivotably coupled to the chassis (<NUM>) via the chassis coupling feature (<NUM>); and a lever (<NUM>) provided with a coupling feature (<NUM>) at a coupling end (<NUM>) configured to engage with the lever engagement feature (<NUM>). The lever (<NUM>) may comprise a handle region (<NUM>) at a free end (<NUM>) opposite to the coupling end (<NUM>).

The coupling feature (<NUM>) of the lever (<NUM>) and the lever engagement feature (<NUM>) may be configured so that the coupling feature (<NUM>) of the lever (<NUM>) is a passage (<NUM>) defined by a wall of the lever (<NUM>), the passage (<NUM>) configured to receive the lever engagement feature (<NUM>) of the wheel arm (<NUM>).

The lever engagement feature (<NUM>) may be the cavity (<NUM>, <NUM>), and the coupling feature (<NUM>) of the lever (<NUM>) may be configured to extend into the cavity (<NUM>, <NUM>).

There may also be provided a method of operation of a towed howitzer system (<NUM>), pivoting from a towing configuration to a firing configuration, the howitzer system comprising: a wheel arm (<NUM>) pivotably coupled to a chassis (<NUM>) of the howitzer; the wheel arm (<NUM>) comprising a chassis coupling feature (<NUM>) centred on an arm pivoting axis (<NUM>) and a wheel coupling feature (<NUM>) centred on a wheel rotation axis (<NUM>). The chassis coupling feature (<NUM>) may be spaced apart from the wheel coupling feature (<NUM>). A lever (<NUM>) may extend from the wheel arm (<NUM>) to a handle region (<NUM>) at a free end (<NUM>). The lever (<NUM>), the wheel coupling feature (<NUM>) and chassis coupling feature (<NUM>) may be provided in series along the length of the wheel arm (<NUM>). The method may comprise the steps of : a user (<NUM>) grasping the handle region (<NUM>) of the lever (<NUM>) and applying a force to the lever (<NUM>) so that the wheel arm (<NUM>) pivots relative to the chassis (<NUM>) about the arm pivoting axis (<NUM>).

The method of operation may further comprise the step of coupling the lever (<NUM>) to the wheel arm (<NUM>).

The method of operation may further comprise the step of the step of coupling the lever (<NUM>) to the wheel arm (<NUM>) so that the handle region (<NUM>) of the lever (<NUM>) is positioned just below shoulder height of the user when the user is kneeling.

The howitzer system may further comprise a suspension system. The method may further comprise the step of operating the suspension system with the lever (<NUM>) when the lever (<NUM>) is disconnected from the wheel arm (<NUM>).

There may also be provided a method of manufacture of a wheel arm (<NUM>) according to the present disclosure, comprising the steps of : providing a wheel arm precursor; attaching a lever engagement feature (<NUM>) to the wheel arm (<NUM>).

The method of manufacture may further comprise the step of : preparing the region of the wheel arm precursor to which the lever engagement feature (<NUM>) is to be attached before attaching the lever engagement feature (<NUM>) to the wheel arm precursor.

Hence there is provided a wheel arm and a towed howitzer system. These reduce risk to the user, and increases the chances of a successful weapon deployment regardless of the conditions. The provision of a lever engagement feature on the wheel arm enables a lever to be attached to the wheel arm so the wheels of the towed howitzer may be moved between a towing configuration and a firing configuration, and back again, in an operation that is less strenuous than possible with arrangements of the related art, such that the operation may comply with Health and Safety Guidelines.

The present disclosure relates to a wheel arm and a towed howitzer system including a wheel arm of the present disclosure.

The howitzer system <NUM> of the present disclosure comprises a weapon unit <NUM> carried on a chassis <NUM>. A wheel arm <NUM> extends from either side of the chassis <NUM>. Each wheel arm <NUM> extends from the chassis <NUM> to support a wheel <NUM> which supports the chassis <NUM> when it is being transported (i.e. towed). A suspension system (not shown, but may be of a conventional kind) is provided to further support the wheel arms <NUM>.

A first example of a wheel arm <NUM> according to the present disclosure is shown in <FIG>. A second example of a wheel arm according to the present disclosure is shown in <FIG>.

<FIG> shows a side view of a wheel arm <NUM> on which a wheel <NUM> of the howitzer system is rotatably mounted.

The wheel arm <NUM> is pivotably coupled/mounted to the chassis <NUM>. As shown in <FIG>, the wheel arm <NUM> may comprise a chassis coupling feature <NUM> (for example a bearing unit or part thereof) which centred on an arm pivoting axis <NUM>, and is configured to allow the wheel arm <NUM> to pivot relative to the chassis <NUM> about the arm pivoting axis <NUM>. The wheel arm <NUM> may also comprise a wheel coupling feature <NUM> (for example a bearing unit or part thereof) centred on a wheel rotation axis <NUM>, for rotatably mounting a wheel <NUM> to the wheel arm <NUM>, and configured to allow the wheel <NUM> to rotate relative to the wheel arm <NUM> around the wheel rotation axis <NUM>.

The wheel arm <NUM> is configured to be coupled to a suspension system, either directly or indirectly, so that the wheel coupling feature <NUM> is spaced apart from the chassis <NUM> by the suspension system. The suspension system may be of a conventional kind, and configured to damp vibrations and shock loads when the howitzer is being transported on its wheels <NUM>.

The chassis coupling feature <NUM> is spaced apart from the wheel coupling feature <NUM>. Hence the arm pivoting axis <NUM> is spaced apart from the wheel rotation axis <NUM>.

A line (shown as line "A-A" in <FIG>, <FIG>) which extends between the arm pivoting axis <NUM> and wheel rotation axis <NUM> defines a longitudinal axis <NUM> of the wheel arm <NUM>. Hence the nominal length of the wheel arm <NUM> extends along the line A-A. That is to say, the line A-A defines the longitudinal axis <NUM> (e.g. directional "length") of the wheel arm <NUM>. This is the case even where, as shown in the example of <FIG>, the wheel arm <NUM> may have a "dog leg" shape (i.e. not straight).

As shown in <FIG> there may also be provided a lever <NUM> which is operable to extend from the wheel arm <NUM> to a handle region <NUM> at a free end <NUM> of the lever <NUM>. The lever <NUM>, the wheel coupling feature <NUM> and chassis coupling feature <NUM> may be provided in series along the length (i.e. longitudinal axis <NUM>) of the wheel arm <NUM>. Hence the lever <NUM>, the wheel rotation axis <NUM> and the arm pivoting axis <NUM> and may be arranged in series along the length (i.e. longitudinal axis <NUM>) of the wheel arm <NUM>. The lever <NUM> may be provided separately to the wheel arm <NUM>.

The wheel arm <NUM> may comprise a lever engagement feature <NUM>, as shown in <FIG>, <FIG>, to couple/engage the lever <NUM> and the wheel arm <NUM>.

The lever <NUM> may comprise a coupling feature <NUM> at a coupling end <NUM> configured to engage with the lever engagement feature <NUM>, with the handle region <NUM> and free end <NUM> being opposite to the coupling end <NUM>.

The wheel coupling feature <NUM> is located between the lever engagement feature <NUM> (and/or lever <NUM>) and the chassis coupling feature <NUM>. The wheel rotation axis <NUM> may be located between the lever engagement feature <NUM> (and/or lever <NUM>) and the wheel arm pivoting axis <NUM> along the length (i.e. longitudinal axis <NUM>) of the wheel arm <NUM>.

<FIG> shows how the wheel arm <NUM> may be pivoted from one configuration to another about the arm pivoting axis <NUM>. <FIG> show how the wheel arms <NUM> of a howitzer system according to the present disclosure may be pivoted from a towing configuration (<FIG>) to an initial deployed configuration (<FIG>) and then to a firing configuration (<FIG>). The wheel arm <NUM> may be disconnected from the suspension system (e.g. from supporting struts of the suspension system) between the initial deployed configuration (<FIG>) and firing configuration (<FIG>), although remains coupled to the chassis <NUM> by the chassis coupling feature <NUM>.

<FIG> show how the wheel arms <NUM> of a howitzer system according to the present disclosure may be pivoted from a firing configuration (<FIG>) to an initial "wheels on ground" configuration (<FIG>) and then a towing configuration (<FIG>). The wheel arm <NUM> may be connected to the suspension system between the initial deployed configuration (<FIG>) and firing configuration (<FIG>).

In the example shown in <FIG>, the lever engagement feature <NUM> may be provided as a protrusion <NUM> which extends away from the wheel arm <NUM> along an engagement feature axis <NUM>. The protrusion <NUM> may be in the form of a spigot or other extension. The protrusion <NUM> may be provided at or towards the end of the wheel arm <NUM> distal to the arm pivoting axis <NUM>/chassis coupling feature <NUM>. The protrusion <NUM> may extend from the nominal top, bottom and/or sides of the wheel arm <NUM>.

The protrusion <NUM> comprises a wall <NUM> which defines a cavity <NUM>. Hence the protrusion <NUM> may be hollow, for example a hollow tube, as shown in <FIG>. The wall <NUM> defines an opening <NUM> centred on the engagement feature axis <NUM>. The cavity <NUM> is centred on, and extends along, the engagement feature axis <NUM>. A drain aperture <NUM> extends through the wall <NUM> at an angle (e.g. at right angles) to the engagement feature axis <NUM>. As shown in the examples of <FIG>, there may be provided a plurality of drain apertures <NUM> which each extend through the wall <NUM> at an angle to the engagement feature axis <NUM>. The apertures <NUM> may be provided around the circumference of the wall <NUM> and/or in lines along the length of the wall <NUM> (for example along the nominal top and bottom surfaces of the wall <NUM>). The drain apertures <NUM> are provided so that any water, dirt and foreign objects may be expelled from the cavity <NUM>.

In the alternative example of <FIG>, the lever engagement feature <NUM> is provided as a cavity <NUM> which extends into the wheel arm <NUM>. The cavity <NUM> has at least one opening <NUM> to the outside of the wheel arm <NUM>. As in the preceding examples, drain apertures as described in relation to the examples of <FIG> may also be provided in this example. The opening <NUM> is centred on the engagement feature axis <NUM>. The cavity <NUM> is centred on, and extends along, the engagement feature axis <NUM>.

In both examples, the lever engagement feature <NUM> may be formed integrally with the wheel arm <NUM>, welded to the wheel arm, and/or attached by some mechanical means, for example a bracket or adapter using a fixing means such as a bolt, screw and/or rivet.

In the examples shown the engagement feature axis <NUM> is provided at an angle "B" to the longitudinal axis <NUM> (line A-A). The angle B may be at least <NUM> degrees but not more than <NUM> degrees. The angle B may be at least <NUM> degrees but not more than <NUM> degrees. The angle B may be at least <NUM> degrees but not more than <NUM> degrees. The angle B may be at least <NUM> degrees but not more than <NUM> degrees.

In an alternative example the engagement feature axis <NUM> is aligned with the longitudinal axis <NUM> (line A-A). In further alternative example the engagement feature axis <NUM> is parallel to the longitudinal axis <NUM> (line A-A).

The lever engagement feature <NUM>, the wheel coupling feature <NUM> and chassis coupling feature <NUM> are provided in series along the length of the wheel arm <NUM>. Hence the arm pivoting axis <NUM>, wheel rotation axis <NUM> and lever engagement feature <NUM> are provided in series along the length of the wheel arm <NUM>.

In the examples shown, the coupling feature <NUM> of the lever <NUM> is configured to extend into the cavity <NUM>, <NUM> of the lever engagement feature <NUM>. Hence in this example the external diameter of the coupling feature <NUM> of the lever <NUM> is slightly smaller than the internal diameter of the cavity <NUM>, <NUM>. The lever <NUM> is thus located and engaged with the wheel arm <NUM> via the lever engagement feature <NUM>. Any foreign matter in the cavity <NUM>, <NUM> may be expelled through the drain apertures <NUM> by the insertion of the lever <NUM> into the cavity <NUM>, <NUM>.

In an alternative example, the coupling feature <NUM> of the lever <NUM> and the lever engagement feature <NUM> are configured so that the coupling feature <NUM> of the lever <NUM> is a passage <NUM> defined by a wall of the lever <NUM>. In such an example the lever engagement feature <NUM> (e.g. the protruding spigot) is configured to be received by the passage <NUM> of the lever <NUM>. Hence in this example the internal diameter of the passage <NUM> of the lever coupling feature <NUM> is greater than the external diameter of the protrusion <NUM>.

Hence the lever <NUM> is attached to the lever engagement feature <NUM> spigot/protrusion at the end, or towards one end, of the wheel arm <NUM>. The lever <NUM> and lever engagement feature <NUM> may be engaged/disengaged by sliding one relative to the other.

The distance from the coupling end <NUM> of the lever <NUM> to the handle region <NUM> may be the same or greater than the distance from the arm pivoting axis <NUM> to where the lever engagement feature <NUM> extends from the wheel arm <NUM>. The distance from the coupling end <NUM> of the lever <NUM> to the handle region <NUM> may be twice, but no more than three times, the distance from the arm pivoting axis <NUM> to where the lever engagement feature <NUM> extends from the wheel arm <NUM>.

The length of the lever <NUM>, and the angle B, are configured, determined and/or set such that with the lever <NUM> coupled to the wheel arm <NUM>, and/or the lever <NUM> extending from the wheel arm <NUM>, with the wheel <NUM> supported on the ground, a user kneeling on the same ground, at the same level, may have the handle region <NUM> of the lever <NUM> positioned at about shoulder height.

The lever <NUM> may also be configured for other operations. For example the lever <NUM> may be operable to engage with the chassis suspension, and used to pump up (e.g. pressurise) the suspension (i.e. to change the configuration from an initial "wheels on ground" configuration (<FIG>) to the towing configuration (<FIG>). Hence the lever <NUM> may be configured to be disconnected from the wheel arm <NUM> once the wheels are in the "wheels on ground" configuration (<FIG>) so that the lever may be used to pressurise the suspension.

When not in use, the lever <NUM> may be stored on or in the chassis <NUM>.

A method of operation of the apparatus may comprise the steps of the user <NUM> grasping the handle region <NUM> of the lever <NUM> extending from the wheel arm <NUM>, and applying a force to the lever <NUM> so that the wheel arm <NUM> pivots relative to the chassis <NUM> about the wheel arm pivoting axis <NUM>. Hence by using the lever <NUM> the wheel arm <NUM> may be pivoted so that the wheels <NUM> are pivoted from an initial "wheels on ground" or "initial deployed configuration" (i.e. when the chassis <NUM> has been lowered to the ground, as shown in <FIG>) to a configuration in which the weapon can be fired (the "firing configuration", as shown in <FIG>, <FIG>). The wheel arms <NUM> may be pivoted using the lever <NUM> so that the wheels <NUM> are pivoted from the "firing position" as shown in <FIG> to a configuration in which the howitzer may be prepared for being towed (an "initial deployed configuration", as shown in <FIG>). For example, when the gun needs to be moved, the wheel arms <NUM> are pivoted using the lever <NUM> so the wheels are in a ground supporting position (the "initial deployed position" in <FIG>) and the suspension system of the howitzer is then connected and/or pumped up to bring the howitzer to a "towing configuration", as shown in <FIG>, in which the chassis <NUM> has been lifted clear of the ground.

The method of operation may further comprise the step of coupling the lever <NUM> to the wheel arm <NUM>. This may be done in the "initial deployed configuration" (<FIG>) or the firing configuration (<FIG>). The method of operation may further comprise the step of de-coupling the lever <NUM> from the wheel arm <NUM>. This may be done in the firing configuration (<FIG>) or in the "wheels on ground" configuration (<FIG>). The method of operation may further comprise the step of coupling the lever <NUM> to the suspension system, and then using the lever <NUM> to configure the suspension system (for example to pump/pressurise the suspension system in preparation for towing of the howitzer, <FIG>).

Hence the method may comprise the step of operating the suspension system with the lever <NUM> when the lever <NUM> is disconnected from the wheel arm <NUM>.

The method of operation may further comprise the step of deploying the lever <NUM>.

The method may also comprise the steps of attaching the lever <NUM> to the lever engagement feature <NUM> on the wheel arm such that, when the wheels arms <NUM> and wheels <NUM> are in the "wheels on ground" or "initial deployed configuration" (i.e. when the chassis <NUM> is in contact with the ground, as shown in <FIG>, <FIG>) the end <NUM> of the lever <NUM> is approximately the height of a user's shoulder when the user is kneeling down (for example on one knee). That is to say the method of operation may comprise the step of coupling the lever <NUM> to the wheel arm <NUM> when the wheels are supported on the ground so that the handle region <NUM> of the lever <NUM> is positioned just below shoulder height of a user when the user is kneeling on the same level (i.e. on the same ground) as the wheel <NUM>. Hence for example, with reference to <FIG>, the method of operation may comprise the step of coupling the lever <NUM> to the wheel arm <NUM>, and/or extending the lever <NUM> from the wheel arm <NUM>, when the wheels are supported on the ground so a user kneeling on the same ground, at the same level, may have the handle region <NUM> of the lever <NUM> positioned at about shoulder height.

In this configuration a user may deploy most of the force required using his/her leg muscles, moving from a kneeling position to a standing position, with one arm close to his/her body, and his/her other arm used to steady the lever to thus move the wheel arms <NUM> from the "initial deployed configuration" (as shown in <FIG>) to the "firing configuration" (as shown in <FIG>). Also a user may deploy most of the force required using his/her leg muscles, with one arm close to his/her body, and his/her other arm used to steady the lever to thus move the wheel arms <NUM> from the "firing configuration" (as shown in <FIG>, <FIG>) to the "wheels on ground" configuration shown in <FIG>.

The process by which the design of the apparatus of the present disclosure are determined and set is based on criteria <NUM> to <NUM> below. In particular the angle B at which the lever <NUM> extends from the wheel arm <NUM>, and length of the lever <NUM>, is a function of the criteria <NUM> to <NUM> below. The method of operation may also include one of more of the following features of criteria <NUM> to <NUM> below.

There may also be provided a method of retro fitting a wheel arm of the present disclosure to an existing howitzer system. The method may include the steps of : removing a wheel arm from a howitzer system and fitting a wheel arm according to the present disclosure to the howitzer system (i.e. replacing a wheel arm of a howitzer system with a wheel arm according to the present disclosure).

There may also be provided a method of manufacture of a wheel arm <NUM>, the method comprising the steps of: providing a wheel arm precursor and attaching a lever engagement feature <NUM> as hereinbefore described to the wheel arm precursor. In this context, the word "wheel arm precursor" is intended to mean an article that forms the basis for, but does not have all of the features of, the wheel arm of the present disclosure.

There may also be provided a method of manufacture of a wheel arm <NUM>, the method comprising the steps of integrally forming a wheel arm <NUM> and lever engagement feature <NUM> as hereinbefore described, for example in a casting or 3D printing process.

There may also be provided a method of retro fitting a lever engagement feature <NUM> to a wheel arm of a howitzer system. This may comprise the steps of attaching/fixing a lever engagement feature <NUM> of the present disclosure to a wheel arm, for example by welding, bonding, bolting or clamping, or some other appropriate method.

There may also be provided a method of replacing a lever engagement feature <NUM> of a wheel arm. This may comprise the step of preparing the region of the wheel arm <NUM> to which the lever engagement feature <NUM> of the present disclosure is to be attached before attaching the lever engagement feature <NUM> to the wheel arm <NUM>. For example, a damaged and/or worn lever engagement feature <NUM> may need to be removed and the surface to which the replacement lever engagement feature <NUM> is to be fixed may need to be configured so that the replacement lever engagement feature <NUM> can be fitted in place.

There may also be provided a kit of parts comprising wheel arm according to the present disclosure and a lever for use with the wheel arm. Additionally or alternatively the kit of parts may comprise a wheel arm precursor and a lever engagement feature configured to be fitted to the wheel arm precursor. The kit of parts may comprise a howitzer chassis <NUM>, a lever <NUM> and a wheel arm <NUM> comprising a lever engagement feature <NUM>.

In an alternative example the lever <NUM> may be configured to be retained in the wheel arm <NUM>, and slid out of the wheel arm <NUM> when required.

There is thus provided a wheel arm <NUM> for a towed howitzer (i.e. a wheel arm <NUM> for fitting to a chassis <NUM> of a towed howitzer system), a towed howitzer system including a wheel arm of the present disclosure, a method of operation of a towed howitzer system including a wheel arm and a method of manufacture of a wheel arm.

Providing a lever engagement feature <NUM> so that they lever may be fixed to the wheel arm <NUM> means that a lever may be used to move the wheel arm <NUM>, and the attached wheel, into a desired position. Additionally or alternatively, configuring the wheel arm to include a lever (that is to say, providing the wheel arm with a lever) provides a technical advantage over examples of the prior art.

The use of a lever provides mechanical advantage for "throwing the wheel over". The lever provides a location for the user to apply a force to the wheel arm which is further from the wheel arm pivoting axis <NUM> than the wheel. That is to say, the lever increases (for example doubles) the available distance to the wheel arm pivoting axis <NUM> for a user to act on, and thereby reduces (for example halves) the required force to pivot the wheel arm. Hence compared to examples of the related art, in which the procedure may require two users to pivot the wheel arm, and put them both risk of injury, the apparatus of the present disclosure results in the same effect being achieved by a single user who can complete the wheel pivot with a reduced risk of injury. The apparatus of the present disclosure also provides the user with a comfortable gripping point (i.e. handle and/or handle region) to move the wheel.

Consequently not only are fewer people required to move the wheels of the howitzer to the desired position, with lower risk of injury, but also other members of the crew are free to conduct other necessary operations, thereby reducing the time to deploy the howitzer, or to configure the howitzer ready to be towed. Hence the provision of a lever for moving the wheel arm has a considerable effect on operational success of the howitzer system.

In examples of the related art, the wheels of the howitzer must be braked to allow users to pivot their wheels. If the wheels are free to rotate about their respective wheel rotation axes it is harder to hold the wheel while it is being pivoted about the wheel arm pivoting axis. If the brake has failed, or a user omits to apply the brake, then the rotation of the wheel can cause serious injury, for example because rotation of the wheel can cause a user to lose their grip and/or balance and suffer injury, for example if they fall or twist a body part. However, the equipment of the present disclosure does not require the brakes to be applied because the user does not need to hold the wheel in order to pivot the wheel arm to the desired position, and hence a further problem of the related art is avoided.

Claim 1:
A wheel arm (<NUM>) for a chassis (<NUM>) of a towed howitzer system (<NUM>), the wheel arm (<NUM>) comprising :
a chassis coupling feature (<NUM>) centred on a wheel arm pivoting axis (<NUM>), and a wheel coupling feature (<NUM>) centred on a wheel rotation axis (<NUM>), wherein the chassis coupling feature (<NUM>) is spaced apart from the wheel coupling feature (<NUM>);
the wheel arm (<NUM>) comprises a lever engagement feature (<NUM>),
wherein the lever engagement feature (<NUM>), the wheel coupling feature (<NUM>) and the chassis coupling feature (<NUM>) are provided in series along the length of the wheel arm (<NUM>)
the lever engagement feature (<NUM>) is provided as a protrusion (<NUM>) which extends away from the wheel arm (<NUM>) along an engagement feature axis (<NUM>);
the protrusion (<NUM>) comprises a wall (<NUM>) which defines a cavity (<NUM>),
with an opening (<NUM>) centred on the engagement feature axis (<NUM>); the wheel arm being characterised in that a drain aperture (<NUM>) extends through the wall (<NUM>).