Abstract:
The invention relates to a recoil impulse generator for a weapon simulator comprising a force storage element and an impulse mass that can be moved and that is moved from a stressed to an unstressed position with a triggering element is actuated in order to simulate a recoil impulse. The recoil impulse generator comprises a drive that drives a spindle uninterruptedly during a shot sequence simulating several shots; a coupling that is connected to the impulse mass and to the force storage element and that engages in the spindle in an engaged state and that is moved along the spindle by means of rotation of the spindle in order to bring the impulse mass into the stressed position again the force applied by the force storage element; a disengaging means that switches the coupling to a disengaged state when the impulse mass has reached the stressed position; and an engaging means that switches the coupling to the engaged state when the impulse mass has reached the unstressed position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application of PCT/EP2010/051502, filed Feb. 8, 2010, which claims priority to European application no. 09152527.9, filed Feb. 11, 2009, the entirety of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention concerns a recoil impulse generator for a weapon simulator comprising a force storage element and a movable impulse mass that is moved from a stressed to an unstressed position when a trigger element is actuated by the force storage element in order to generate a recoil impulse. In general the recoil of the most varied weapons can be simulated with a recoil impulse generator. The recoil impulse generator considered here is suitable preferably for hand gun simulators. 
     US 2008/0155875 A1 describes a mechanism for the recoil impulse generation in a toy gun. There an electric motor drives a piston of a compressed air cylinder via a multi-part reduction gear. The return of an impulse mass is effected by pneumatic means. 
     From DE 27 26 396 C2 a device is known for the simulation of the recoil force of a weapon. For this purpose a recoil generator is provided that is structurally separate from the weapon and that transfers an adjustable recoil force to the barrel of the weapon. Because of the structural size the device has to be permanently installed at a shooting range and is particularly suitable for coupling to rifles. The handling characteristics of the weapon change significantly due to the external lever action that is acting on the rifle, so that the shooting simulation corresponds only in part to the actual circumstances during use of the weapon. 
     DE 36 31 262 A1 describes a device for the shooting simulation of a hand gun. The bolt in the hand gun simulator is moved for that purpose by means of electromagnetic or gas pressure-activated drive means against the force of the recoil spring into the open position. In this constellation either strong drive elements have to be used or the recoil force that can be generated is too small. The generation of large recoil simulation forces would require a very strong electromagnet, which structurally could barely be accommodated in a hand gun and additionally would have a high energy consumption. If instead a gas pressure cartridge is used as drive means, it would have to be frequently exchanged if it were used to provide realistic forces. The attachment of a gas pressure cartridge to the front part of the barrel of the hand gun, as it is proposed in the printed specification, also prevents the simultaneous disposition of a target system on the front barrel section, which likewise is required for a complete hand gun simulator. 
     DE 103 50 307 A1 demonstrates a simulation device for the simulation of the semi- or fully automatic function of a firearm. For example, a propellant container that is disposed in the breech block is connected to a cylinder and propels a movable piston via a valve. Here also the actually achievable recoil forces are significantly lower than those associated with an actual shot because the forces that can be exerted are not as large as those that arise during the firing of a cartridge, due to the limited propellant amounts. 
     In EP 1 043 561 A2 a weapon simulator is described that can be used in particular in a battle tank. Here a slide serves the purpose of transporting a training projectile. The slide is driven by two parallel spindles. 
     U.S. Pat. No. 2,472,002 describes a screw- and self-holding mechanism that can be used for example in an airplane-machine gun and is used for re-cocking the weapon after it has malfunctioned. The mechanism uses a spindle that is driven by an electric motor, an impulse mass and a coil spring as a force storage element. A coupling is formed by the housing that feeds bearing spheres into the spindle in order to be axially displaced. The coupling is disengaged when the impulse mass has been moved into the stressed position, and engaged when the impulse mass has returned into the unstressed position. The described mechanism is only used occasionally to cock the weapon since firearm malfunctions occur only occasionally, so that the motor also is not designed for permanent use. 
     SUMMARY OF THE INVENTION 
     It is therefore the object of the invention at issue to provide an improved recoil impulse generator for a weapon simulator that generates realistic recoil forces and at the same time avoids the disadvantages of prior art. In particular the frequent replacement of propellant cartridges is to be avoided. Likewise undesirable high electromagnetic fields, as they are generated by strong electromagnets, should be avoided. In addition the weapon simulator should not exceed the dimensions, weight, balance, and the shape of an actual weapon, in particular not a hand gun, and it should provide sufficient space for installing a target-finding or target-acquisition unit despite the installation of the recoil impulse generator. Finally the recoil impulse generator should be universally adaptable to different firearm simulators so that pistols, long guns as well as also other weapons that generate recoil can be equipped therewith. 
     The stated objective is met using a recoil impulse generator for a weapon simulator with the characteristics stated in claim  1 . 
     According to the invention the recoil impulse generator uses a drive, for example an electric motor, that continuously drives a spindle during a shot sequence that simulates several shots, such that via said spindle a coupling as well as a connected impulse mass are moved from the unstressed position to the stressed position, while simultaneously the force storage element is tensioned, which can be implemented for example as a trigger spring, pneumatic element, fly wheel or similar. In what follows a slide of a hand gun, which together with the coupling represents the moving mass that generates the simulated recoil impulse, is considered as a typical example of an impulse mass. In other embodiment forms other parts can form the impulse mass. For the displacement of the slide into the stressed position the coupling engages the spindle, in the engaged state and in a preferably rotationally movable manner, so that it is moved during the rotation of the spindle along the same, as it is commonly known in the case of a linear drive. The coupling is switched to a disengaged state by a disengaging means as soon as the slide has reached the stressed position. During the actuation of the trigger element, which is for example implemented by a trigger, the force storage element accelerates the slide and the disengaged coupling that is attached to it (together with the impulse mass) preferably in a direction opposite the shooting direction. This acceleration and in particular the slide striking in the unstressed position simulate the recoil force realistically. Finally an engaging means is available that switches the coupling into the engaged state again as soon as the slide has reached the unstressed position, in order to again place it in the stressed position in preparation for a further shot simulation. 
     The electric motor is preferably a brush-less synchronous motor that can achieve high rotational speed (approximately 20,000 min-1 to 80,000 min-1). In a preferred embodiment the electric motor can be coupled to the spindle via a transmission or it can also operate as a transmission-less direct drive. The transmission is implemented for example with a reduction ratio of 2:1 to 5:1 and can effect an inversion of rotation. It is of importance that a relatively high rotational speed of the spindle (or a high torque at lower rotational speed) is achieved in order to convey the slide from the unstressed position into the stressed position in a short time. This time corresponds to the duration of automatic reloading in the case of semi-automatic hand guns and should preferably require less than one second. In order to simulate such fast reloading times the electric motor is continuously operated during a shot sequence according to the invention, so that the drive forces act immediately on the slide while the coupling engages. This additionally has the advantage that the startup torque that necessarily acts on the hand gun simulator and which arises during startup and braking of the electric motor, no longer appears, or at least to a lesser degree, during the shot sequence, as a result of which targeting errors are avoided or reduced. A symmetrically constructed coupling serves the same purpose in a modified embodiment, wherein it engages the spindle from two facing sides so that the resulting moments are largely compensated. 
     In a particularly preferred embodiment the rotational speed of the electric motor can be reduced while the coupling is not engaging the spindle. The forces that arise while engaging under load and the associated wear can be significantly reduced thereby. 
     Likewise an embodiment is useful that uses two oppositely rotating spindles that simultaneously engage the coupling. Using a corresponding thread design the coupling is axially displaced by both threaded spindles, while arising moments compensate one another. 
     According to a modified embodiment form the recoil impulse generator encompasses one or several sensors that acquire the actual position of the slide or the impulse mass, the coupling, and the trigger or the trigger element. Using the analysis of the sensor signals the sequence can be controlled in the recoil impulse generator and certain particular shooting situations can be simulated, such as for example an empty magazine or a firearm malfunction. 
     Additional advantages, details and further improvements are specified in the following description of a preferred embodiment of the recoil impulse generator according to the invention, in reference to the drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a lateral cut view of a hand gun simulator with a recoil impulse generator according to the invention in an unstressed position; 
         FIG. 2  is a detailed cut view of the recoil impulse generator; 
         FIG. 3  is a lateral cut view of the hand gun simulator with the recoil impulse generator in a stressed position as well as a perspective detail view of a tripping square in the moment of the release of the coupling during activation of the trigger; 
         FIG. 4  is a detail view with a slide stop in an activated position; 
         FIG. 5  is a cut view of the coupling. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  displays a cut view of a hand gun simulator that is as accurate a reproduction in shape and dimensions of an actual hand gun (in this case a pistol) as possible in order to be able to design the simulation as realistically as possible. The simulator encompasses a pistol housing with a hand grip  01 , wherein a magazine slot is provided. A simulator magazine  02  is inserted in the magazine slot instead of the usual cartridge magazine and it contains for example a storage battery  03  as an energy source. Furthermore a slide  04  is provided that glides along the slide-way  05  in the shooting direction and is part of the impulse mass. Furthermore the hand gun simulator encompasses a trigger  06  and a barrel  07 . The recoil impulse generator is disposed in the axial direction of the barrel  07 . 
       FIG. 2  displays a detail representation of the most important elements of the recoil impulse generator in a cut view. An electric motor  08  that is used as a drive and that operates for example at 50,000 revolutions per minute is coupled via a transmission  09  to a spindle  10  in order to propel it to rotate. The transmission  09  can produce a reduction ratio of, for example, 3:1, so that the spindle is still driven at a high rotational speed of about 10,000 m-1 while at the same being able to generate the necessary forces to cock the latch spring  11  that acts as a force storage element. In a preferred embodiment the transmission  09  performs a rotation reversal, which has the advantage that the angular momentum generated by the electric motor  08 , in reference to the axial alignment of the hand gun simulator, is largely compensated by the opposite angular momentum of the transmission  09  and the spindle  10 . The compensation of the angular momentum can be omitted when the moved masses are small relative to the total mass of the simulator weapon. 
     In the displayed embodiment the latch spring  11  is implemented as a coil spring that extends around the spindle  10  and runs between the transmission  09  and the coupling  12 . Other force storage elements can likewise be used. Modified combinations of drive and storage element can be used in other embodiments, such as for example a direct drive, a pneumatic drive, or an electromagnet with a capacitor or a storage coil. 
     The slide  04  is attached to the coupling  12 , so that it is moved along during an axial displacement of the coupling  12 . The end of the spindle  10  facing away from the transmission  09  is supported by a spindle bearing  13  that is fixed to the housing. 
     In  FIGS. 1 and 2  the coupling  12  and the slide  04  attached to it are in the unstressed position I, in which the coupling  12  is positioned away from the transmission  09  and the latch spring  11  is largely unstressed. 
       FIG. 2  displays the coupling  12  in the engaged state, in which several spheres  14  engage the spindle  10 . Modified engagement elements, such as for example cones or pins, can be used instead of the spheres  14 . When the spindle  10  is rotated, an axial movement of the coupling  12  is effected in the direction toward the transmission  09 . As a result the latch spring  11  is compressed and the slide  04  is moved into a stressed position II ( FIG. 3 ). 
     A first sensor  15  determines for example whether the coupling  12  has moved away from the stressed position. If this can be established, operation of the electric motor  08  commences in order to drive the spindle  10  and to again move the coupling  12  with the impulse mass coupled to it into the stressed position. As a result the movement sequence is accelerated because the motor is already being accelerated while the impulse mass is still moving in the direction of the unstressed position, in order to achieve a high cadence. Depending on the control the electric motor can be activated from a standstill or from an idle mode for this purpose and be put into a full-load condition. It is useful in order to facilitate a high shot frequency (cadence) not to turn the electric motor off after disengaging the coupling, but to instead just reduce its rotational speed and to thereby place it in an idle state. The full-load condition is then reached faster by increasing the rotational speed, in particular still during the time in which the slide is flung back from the stressed into the unstressed position. In the case of a lower cadence the motor speed can be further reduced or the motor can be turned off completely. 
     Coupling  12  is designed such that it engages automatically as soon as the unstressed position I is reached. The simplest approach to achieve this is via mechanical engaging means that act on the coupling during its stop in the unstressed position in order to effect the coupling of the spheres  14  to the spindle  10 . The coupling is described in detail further below in reference to  FIG. 5 . 
     A second sensor  16  generates a second sensor signal as soon as the slide  04  reaches the stressed position II and the latch spring  11  is therefore cocked. At this time the coupling  12  disengages, so that the motor and the spindle can continue to rotate in idle mode without that the coupling and the slide that is attached to it are axially further displaced. The disengagement when the stressed position is reached can be implemented through the mechanical action of a disengagement means on the coupling, or it can be initiated by an actuator in reaction to the second sensor signal. Because of the disengagement the cocked state of the weapon simulator can be maintained until the next trigger (firing). At the same time the drive can continue running (if necessary at a lower rotational speed) in order to very quickly facilitate a renewed cocking after the firing. As a result individual firings as well as also sustained firings with extremely high cadence can be simulated. 
       FIG. 3  displays a hand gun simulator with the recoil impulse generator in the stressed position II during the moment the trigger  06  is activated (illustration a) Activation of the trigger pivots two tripping squares  17  that are disposed laterally of the coupling, as can be gathered from the detail view (illustration b), in order to release the coupling  12  that was previously blocked by these tripping squares (a retaining pawl can also be used instead of the tripping squares, or a similar element). The latch spring  11  can be released thereby and the coupling is accelerated with the slide  04  in the direction opposite to the shooting direction until the slide stops in the unstressed position I. The release of the latch spring  11 , the impulse triggered by the stop of the moved masses, and the acceleration of the slide toward the front due to the immediate renewed cocking of the latch spring  11  simulate the recoil during the shot. 
     In the detail view of  FIG. 4  a slide stop  19  is shown in an activated position in which the adjustment of the tripping squares  17  for the release of the coupling  12  is prevented. For this purpose a third sensor  20  ( FIG. 1 ) is attached in the vicinity of trigger  06 , whose sensor signal indicates the discharge of the simulated shot. A control unit (not shown) can analyze the third sensor signal, for example in order to count the number of discharged shots and to activate a catch actuator  21  in the case of an “empty” magazine. The catch actuator  21  pivots the slide stop  19 , which engages the slide, so that it remains in the unstressed position I, relative to the coupling position. The latch spring is cocked even when the slide remains in the unstressed position. The force storage element itself is in a stressed position. Slide stop  19  can only be manually returned into its neutral position. 
     A fourth sensor (not displayed) can furthermore be disposed at trigger  06  such that it detects already the starting phase of a firing, for example by acquiring the squeeze of the trigger still before the pressure point of the trigger is exceeded and the firing commences. The fourth sensor signal indicates that the firing is imminent. The electric motor can therefore for example be brought into the full-load condition early in order to be able to achieve still faster cadences. 
     The embodiment displayed in  FIG. 1  comprises furthermore a block, in particular a retaining pawl actuator  22  that can be activated by a supervisory person during use of the hand gun simulator. The retaining pawl actuator  22  activates a retaining pawl that prevents the tripping squares  17  from releasing the coupling  12  in the stressed position II. A firearm malfunction can thereby be simulated. The control signal for the retaining pawl actuator  22  can for example be transmitted via a wireless communication connection from an external control unit to the hand gun simulator. 
     In general a modified mechanism can also be used as a block. Such a modified blocking mechanism is for example detected by a sensor that controls an actuator. This also permits adapting the response of the trigger to different simulators or conditions. Such mechanical decoupling of the trigger also prevents an accidental triggering that otherwise can occur during vibrations. 
     Due to the compact construction of the recoil impulse generator in the front section of the barrel  7  there is sufficient construction space, as is evident from  FIGS. 1 and 3 , to mount a target acquisition unit  23  there, whose details are however not of importance for the recoil impulse generator. 
       FIG. 5  displays an embodiment of the coupling  12  in a cross sectional view in detail. The coupling  12  has a coupling housing  25  in which an axially displaceable coupling group  26  is inserted. The coupling in the engaged state engages the spindle  10  with spheres  14 , as was already mentioned above. For this purpose the side  27  of the coupling group oriented toward the unstressed position I abuts against a stop (engaging means) in this unstressed position II, so that the coupling group  26  is axially displaced. This effects the displacement of for example eight activation pins  28  that are disposed in parallel to the spindle  10  in the coupling in a manner distributed across the circumferential extent. As a result the spheres  14  are pressed into the helical groove of the spindle  10 , whereby the coupling is placed into the coupled state and propelled into an axial motion by the rotating spindle. As soon as the coupling  12  has reached the stressed position II, it again abuts against a stop (disengaging means) with the side  29  of the coupling group  26  that is facing said position II. The displacement pins  28  are moved in the opposite direction so that the spheres  14  leave the helical groove and the coupling is placed into the disengaged state. An important advantage of the coupling is the possibility of engaging with the spindle  10  rotating under full load, which supports a high cadence. 
     In order to keep abrasions of the coupling, which accelerate wear, to a minimum, it is particularly useful to dispose several spheres  14  in the coupling that simultaneously engage the spindle  10  during coupling. To that end the coupling encompasses several groups of spheres  14 , as displayed in  FIG. 5 . 
     An additional measure for a quick but wear resistant engagement of the coupling is in purposefully incorporating a bearing clearance that permits an axial displacement of the spindle  10 , preferably in the range of ½ to 1 of the slope of the helical groove. If the spheres  14  do not fall into the groove bottom at the moment of engagement but impinge for example on the front face of the flank that points toward the outside, the spindle  10  can axially make way because of the clearance, so that the optimal engagement of the coupling is established as quickly as possible. This also serves to accelerate the coupling process. The spindle can be returned by a spring into the axial starting position after the disengagement.