Australian Patents Act 1990 - Regulation 3.2 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title Electronic firing rate controller for remote operation of an automatic firing weapon 'The following statement is a full description of this invention, including the best method of performing it known to me/us: P1/00/011 5/O1 () H:\dxl\lntroven\NRPortbl\DCC\DXL\6880753_I.docx-14/10/2014 1A The present invention relates to an electronic firing rate controller for remote operation of an automatic firing weapon and more generally to the field of weapons capable of firing a large series of rounds within a short period of time, herein referred to as an automatic weapon or a semi-automatic weapon, and a rate controller for operating and controlling 5 from a remote location the weapon and the rate at which rounds are fired by the weapon. For example, the invention relates to a rate controller for controlling from a remote location the rate at which rounds are fired by the weapon employing a solenoid operated trigger mechanism. 10 Crew served automatic weapons are primarily intended for suppression fire and as such, the dispersion can be fairly high. This is partly due to the weapon itself, but mostly due to the weapon mount and the soldier firing the weapon. When mounted on a remotely controlled weapon station, the weapon is mounted in a significantly more stable 15 environment and the dispersion of the weapon itself becomes significant. The firing rate of recoil- or gas-operated weapons is determined by the dynamics of the weapon itself, as well as external factors such as ammunition and weapon mount, and there will be a natural spread of the firing rate due to variations in the above parameters. The 20 firing rate can be reduced by firing single shots in a controlled sequence with a fixed frequency. Related art is disclosed in US3748960, US3451307, US6976416, US2002/0179077, and US4510844. 25 According to the invention there is provided an electronic apparatus for controlling a firing rate of an automatic firing weapon having an actuator adapted to operate a trigger mechanism of said weapon, said weapon exhibiting a natural free-running firing rate when held triggered, 30 said apparatus comprising an output driver means adapted to provide a drive signal for said actuator, H:\dxl\lntroven\NRPortbl\DCC\DXL\6880753_I.docx-14/10/2014 2 a first single pulse generator means having a single pulse output coupled to an input of the driver means and adapted to generate a single pulse of a duration shorter than a time period of said natural free-running firing rate in response to a single pulse generator means input, and 5 a pulse train generator means having a single pulse output coupled to an input of said first single pulse generator means and adapted to provide to the first single pulse generator means a train of pulses spaced in time a spacing period exceeding said time period of said natural free-running firing rate in response to a pulse train generator means input. 10 Preferred embodiments of the invention may maintain suppression fire using less ammunition, to achieve better precision (reduce inherent spread), to extend the time period between barrel replacement, to extend the time period between filling of ammunition, to achieve semi automatic operation of a fully automatic weapon, preferably without making any significant modifications to the weapon exploiting the present invention. 15 The apparatus is arranged to reduce the firing rate, such as e.g. by firing a number of single shots in a sequence with variable frequency. In the following, the invention will be explained in more detail, and also with reference to 20 the accompanying drawing figures, by way of non-limiting example only, wherein Figure 1 is a schematic representation of an embodiment example of a firearm for automatic operation in connection with a firing rate control apparatus, 25 Figure 2 is a graph illustrating examples of firing drive signals in one example, and actual firings of a weapon, and Figure 3 is a block schematic illustration of an embodiment example of an electronic firing rate control apparatus. 30 H:\dxl\lntroven\NRPortbl\DCC\DXL\6880753_I.docx-14/10/2014 3 An exemplary embodiment of the present invention which is adapted to a firearm with a solenoid operated trigger mechanism includes a transient diode, which is useful in an application of a sequence with pulsing of a voltage to the solenoid. 5 The apparatus is preferably adapted to control the firing points by controlling the pulse duration. A firearm including the present apparatus is operational to fire several single shots in a sequence to "simulate" a weapon having a lower firing rate, which, however, is adapted 10 such that one is enabled to fire only a single shot in a controlled fashion (single shot), alternatively that by single shot it is operable to release remote trigger between each shot. Other operational modes include to set the weapon to an auto rate, or in operation at a reduced rate. This is a variant contemplated achieved by adapting the firing rate control apparatus to generate a control pulse train of pulses each corresponding to a single shot 15 pulse, such as e.g. illustrated by its way of example in figure 2. Advantageously, the firing rate is adjustable by way of a control input to the firing rate controller FRC, thus allowing an adaptation to the best dynamics of the weapon and any possible damping mechanism, whereby an optimum firing rate versus dispersion is 20 achieved. The apparatus is advantageously adapted to control the instant of firing such that it represents single shot firing or a controlled, reduced firing rate in a fully automatic man operated weapon with a remotely controlled triggering arrangement, advantageously in 25 conjunction with a weapon using a solenoid. An example of a fully automatic man operated weapon with a remotely controlled triggering arrangement is a so-called "weapon station", such as e.g. the remote weapon station (RWS) named "PROTECTOR", manufactured by Kongsberg Defense & Aerospace AS. 30 For a further detailed explanation of the firing rate controller FRC apparatus by way of example, reference is first made to the accompanying figure 1.
H:\dxl\lnterwoven\NRPortbl\DCC\DXL\6880753_I.docx-14/10/2014 4 In the well known RWS, such as the PROTECTOR RWS referred to above, remote firing of the automatic firing weapon AFW is controlled by a trigger switch, typically a switch at the operator location. Upon activation of the switch, a current is allowed to flow in the 5 electrical firing circuit that energizes a solenoid which, in turn mechanically operates the trigger mechanism of the weapon. The weapon typically is provided with a selector means, typically in the form of a selector lever, for selecting one of a single shot operation or a fully automatic operation. Accordingly, to select any of the two aforementioned operational modes from a remote location, a further selector actuator is required to allow 10 operation of the mode selector lever of the weapon. According to the present apparatus, a further operational mode is provided which corresponds to the single shot operational mode also for the weapon when set to operate in the fully automatic mode. As an example of a solution adapted to provide the further 15 operational mode, an electronic relay is provided in series with the trigger switch to control a single shot also at a time when the weapon when set to operate in the fully automatic mode. The electronic relay is a time relay which lets the current for the solenoid actuating the trigger mechanism of the weapon to flow for only a fixed time, allowing enough time for the solenoid to energize, and for the firing mechanism to activate to fire the first shot of 20 what could otherwise be an automatic series of firings, and also enough time for the solenoid to de-energize and retract, thereby disabling firing of the weapon, before the second shot of the automatic series of firings is ready to fire. The solenoid (and any additional mechanism) are adapted to operate quickly in order to get a precise control of the weapon. Preferably, only one shot is fired irrespective of weapon, supply voltage, 25 environmental changes and type of ammunition. By repeating the above sequence with a settling time in between each shot, allowing for the weapon and mount to stabilize, a controlled firing rate can be achieved. Various firing rates are advantageously made available for the operator to select from. 30 H:\dxl\lntroven\NRPortbl\DCC\DXL\6880753_I.docx-14/10/2014 4A Furthermore, the firing rate controller apparatus is advantageously designed such that no modifications are required on the weapon itself for it to operate as described herein. The example of a firing rate controller illustrated generally in figure 1 includes at least a 5 firing trigger input T, a mode select input M, and an output Q for providing a signal to actuate the weapon trigger actuator. The functions provided by operation of the T and M inputs are generally as explained above. In an advantageous embodiment of the FRC, additional inputs are provided, such as a rate 10 control input (1/TR), and a solenoid pulse control input (Ts). By the rate control input (1/TR), which has effect the operator is allowed to control the rate of the signal to actuate the weapon trigger actuator for releasing a shot from the weapon in the single shot mode of operation of the weapon itself. When the fully automatic mode has been selected, the l/TR is disregarded. 15 In the examples illustrated in figure 2, four examples of outputs Q are represented by respective plots of a voltage supplied to a trigger solenoid at the weapon. In the first plot from the top drawn in solid line, the voltage is represented by a single pulse output Q of a time duration TT corresponding to the time the trigger switch is closed and which 20 significantly exceeds the time interval between shots TF of the natural fully automatic free running firing rate of the weapon, resulting in the firing of the actual burst series of ten rounds fired by the weapon as illustrated by the dotted line plot immediately below. That dotted line plot of the actual series of ten rounds also illustrates the time period TF between shots released by the natural fully automatic free-running firing rate of the weapon. In the 25 second plot from the top being drawn in solid line, the voltage is represented by a single pulse output Q of a time duration Ts that is shorter than the time interval TF between shots fired by the natural fully automatic firing rate of the weapon, 5 resulting in the releasing of only a single shot from the weapon. In the third plot from the top being drawn in solid line, the voltage is represented by a series of eight single pulses output Q, where each single pulse of a time duration Ts is repeated at intervals of duration TR which is shorter than the time interval TF between shots fired by the natural 5 fully automatic free-running firing rate of the weapon, resulting in the releasing of a series of eight shots from the weapon at a reduced rate that is 8/10 of the natural fully automatic free-running firing rate of the weapon in this example. In the fourth plot from the top being drawn in solid line, the voltage is represented by a single pulse output Q of a time duration TB which still significantly exceeds the time interval between TF io shots the natural fully automatic firing rate of the weapon but is shorter than the duration of the pulse illustrated by the top graph, resulting in the firing of the reduced actual burst series of five rounds fired by the weapon illustrated by the dotted line plot immediately below. is In figure 3, an embodiment example of a firing rate controller circuit is illustrated in a block schematic representation. The circuit example includes, connected in series, a solenoid driver SDRV providing the pulse output Q and receiving an input from a first monostable multivibrator MMV1 receiving an input from a first astable multivibrator AMV1 receiving an input from a second monostable multivibrator MMV2, and a mode 20 control selector M and a trigger switch T providing inputs to any of the SDRV, MMVI, AMV 1, or MMV2. Advantageously, any of MMV 1 and MMV2 is a non-retriggerable type of monostable multivibrator Accordingly, SDRV is driven by an output Q l provided by the MMV 1, which in turn is 25 driven by an output Q2 provided by the AMV 1, which in turn is driven by output Q3 provided by the MMV2. Any of the SDRV, MMV1, AMVI and MMV2 are further adapted to be driven each by respective a respective one of mode selector M outputs FSU, SSC, MSC and BSC provided by M and in accordance with an operation of the trigger switch T. 30 Thus, in response to closing the trigger switch T with the mode selector a) set to output FSU (free-running shot uncontrolled), DRV provides an output Q for as long as T is closed, b) set to output SSC (single shot controlled), DRV provides an output Q of duration Ts, 35 c) set to output MSC (multi shot controlled), DRV provides an output Q of a series of pulses of duration Ts at a rate I/Tr for as long as T is closed, and H:\dxl\lntroven\NRPortbl\DCC\DXL\6880753_I.docx-14/10/2014 6 d) set to BSC (burst shot controlled), DRV provides an output Q of duration Tb for as long as T is closed. The embodiment example of a firing rate controller circuit illustrated in a block schematic 5 representation in figure 3 lends itself readily to be made in a modular construction. As an example, any of MMV2 or AMV1 could be omitted to provide a simpler controller with fewer functions, then AMV1 could be introduced subsequently to provide the reduced rate series function, and then, MMV2 could be introduced subsequently to provide the limited burst at reduced rate series function. 10 The circuit example includes a solenoid driver SDRV, advantageously designed as a module in the FRC, that could be replaced by a different type of driver module in case the weapon trigger mechanism actuator is not a solenoid type actuator. Accordingly, it is contemplated to adapt the FRC to include a driver module for a pneumatic or hydraulic 15 actuator at the AFW to allow remote firing control of the weapon without relying on a transmission of an electrical type of signal from the driver to the actuator at the weapon station. It is contemplated to embody the FRC using a programmable controller device, such as for 20 example a programmable microcontroller or the like, to create therein any or all of the functional elements of the SDRV, MMV1, AMV, and MMV2. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will 25 be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or 30 admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.