EQUIPMENT WITH ENERGY KNOCKING-DOWN SEPTUM FOR BULLETS, TO BE INSTALLED IN SHOOTING RANGES

Abstract: The knocking-down septum comprises at least a steel shutter structure (3), on the slats of which a granulated material (S) rests, which material - by lying on the slats of the shutter structure (3) according to its natural angle of repose (S2) - is retained by the same shutter; the thickness of the granulated material (S) is crossed by the bullets, which thus slow down their velocity, and consists of granules of natural or synthetic rubber, also of recovery and possibly of a self-extinguishing type, of dry sand, or of a mixture of sand and rubber or the like.

Description: The invention relates to an apparatus having the purpose of lowering, even as down as it is undone, the speed of a bullet at least to such a value that, striking just the same against a back surface - of steel or other - with an incidence angle even of ninety degrees, no phenomena of lead sublimation or pulverization take place. This speed will be indicated in the description as safety speed. The element characterizing the system, is a shutter structure with steel slats, on which a granulated material is made to rest, which material - by lying on the slats of the shutter structure according to its natural angle of repose - is contained by the same shutter. This material is entrusted with the task of reducing the speed of the bullets and to this end it must have a thickness which is a function of the type of the weapons used and must consist of granules of natural or synthetic rubber also of recovery and possibly of self-extinguishing type, or of dry sand, or of a mixture of rubber and sand. The slats of the shutter may be horizontal or with an upward inclination. In a possible solution, the structure of the shutter defining the exit surface is inclined so as to result parallel to the stability surface of the granulated material. In this case, no expedient is necessary to hold the same granulated material, and the entrance surface of the bullets is developed with the inclination of the friction cone. In another possible solution, the shutter is placed with a less inclined attitude - in respect to the vertical line - than that of the friction cone, and even vertically placed. In this case, the braking mass may be held - on the bullets entrance side - by a vertical panel of rubber, even regenerated, which can be possibly reinforced with music wires, in order to define the entrance surface of the bullets in the knocking-down septum. Alternatively, the entrance surface of the bullets may be also developed with a shutter structure; advantageously, this structure exhibits slats more widely spaced than those of the shutter structure defining the side of the bullets exit. The shutter structure may have such a disposition that one part of the bullets goes directly through the braking layer with a residual kinetic energy which also causes the backwardly coming out of small quantities of granules as well as of bullets previously stopped on the layer for several reasons; on the back of the shutter structure, a surface for the inerception and the falling along the inclined plane of the bullets and the granules, is disposed. The slats may be slightly inclined downwards and in the direction of the bullets movement, and in opposite direction, to ensure the function of partial discharge of the granules with the bullets passing the barrier owing to their residual energy. The intercepting surface may be elastically mounted so as to vibrate thanks to the residual energy of the bullets being intercepted by the same surface. The intercepting surface may be combined in the lower part with a sieve, that is, a classification grate through which the separation is directly provided of the granules form the bullets which are retained and delivered to a collector. The vibrations ease the descent of the material and the screening thereof. Just upstream of the grate, a diaphragm may be provided, which retains the material to be graded and ensures the regular delivery thereof to the sieve. To collect the material falling through the sieve, a transverse conveyor may be provided located therebelow. A collector for the bullets may be realized of overturnable type for the discharge; said collector can perform the discharge into said conveyor during a work phase thereof intended to move away the bullets, during which the conveyor can operate with a reverse motion. To the intercepting surface damping diaphragms, vibrating therewith, may be advantageously associated being inclined upwards and in the direction of the bullets motion, in order to intercept them and dampen their kinetic energy. The layer thickness of the material supported by the structure may be controlled both upstream - that is in the upper part - and downstream - that is in the lower part - by means of gates which advantageously move in their plane, mostly a horizontal plane. A lower gate may substantially make up the last of the slats, and can be moved in one direction or the other to increase, respectively decrease, the thickness, and can also reach a position in which it consents the almost complete discharge of the inclined layer supported by the shutter structure. The purpose of the invention is to realize an apparatus able to offer - in respect to other known apparatuses - special functional characteristics and in particular: to obtain a soft damping of the bullet kinetic energy, so as not to generate lead vapours or dust; to prevent the bullets from stopping stably in the braking mass, so as not to create the so-called "lead wall"; to obtain an automatic separation of the bullets from the granules in the same butt during the drill and without the aid of machineries, but exclusively by exploiting the gravity and the residual kinetic energy of the bullets. The invention will be better understood by following the description and the attached drawing, which shows a practical non limitative exemplification of the same invention. In the drawing: Fig. 1 shows in cross section a first example of embodiment; Fig. 2 being an enlarged detail of Fig. 1; Fig. 3 shows in vertical section a second feasible embodiment; Fig. 4 shows a front view of the entrance surface of the bullets in the embodiment of Fig. 3; and Fig. 5 shows a modified embodiment; Fig. 6 shows an ensemble vertical section of another embodiment; Figs. 7 and 8 show two enlarged details of Fig. 6; Fig. 9 shows a possible modified embodiment; Fig. 10 shows a further embodiment; Figs. 11 and 12 show an enlarged detail of a gate in two different arrangements; Figs. 13, 14 and 15 show yet a further embodiment similarly to Figs. 10, 11 and 12. According to what is illustrated in the attached drawing, in which f1 indicates the incoming direction of the bullets, the septum intended to knock down the bullets energy is defined by a layer S of granulated material - like rubber, even of fireproof type, and possibly of rubber recovery type, or dry sand, or a mixture of these materials - which is disposed with the typical inclination of the friction cone that is of the natural declivity of the material itself in conformity of the characteristics of the material and of its granulometry. The layer is defined, in its front surface S1, by the free surface of the material in its natural inclination; the bullets exit surface, that is, the rear surface, is defined by a shutter structure made up of slats 3 which may be made of steel or other suitable material and with a horizontal or slightly upwardly inclined orientation and in the direction of the arrow f1; between one slat and the other, however, the material sets itself according to the surfaces S2 which are surfaces of natural declivity as well. The slats may have a thickness in the range of 7-9 mm and an interspace in the range of 200 mm. Fig. 1 shows the structures combined with the septum in question. In particular, a wall 5 is indicated which receives the bullets and the granules dragged along by them, this material being able to be collected on the bottom or discharged directly into a conveyor 7 and amassed in a collector 9, from which it may be then discharged by an elevator 10 onto a sieve 12 in order to separate the particles which cross the sieve from the bullets retained by the sieve; an elevator 14 may provide for the discharge of the material into a reservoir 16 overhanging the septum S and capable of continuously restoring the configuration of this septum. The material may be also discharged into a reservoir 18 located at the back of the wall 5, for any necessity of storage, of variation of the septum thickness, or for other requirements, as provided for other similar applications. A diaphragm 20, that can be adjusted in position through a cylinder-piston system 22, can be moved for positioning its lower edge so as to delimit the thickness of the septum S by the position of said edge, and to change the septum thickness by the displacement of the same edge. In the embodiment of Figs. 3 and 4, the septum S10 is defined on the back by a shutter structure having slats 23 which are disposed according to a substantially vertical development, while the shutter structure of the previous example has an inclination corresponding to that of the surface S1; between the slats 23, the granulated material takes up the configuration shown by the surfaces S12 with the inclination of its natural declivity, while the front surface of the bullets entrance that arrive according to the arrow f10, is defined by a vertical wall 26 which is crossed by the bullets and may be made of rubber - even of regenerated type - reinforced with music wires or other; said wall can be subdivided in panels variously replaceable and mounted on a framework 28 as shown in Figs. 3 and 4. Even in this case a reservoir 30, corresponding to the one indicated by 16 in the preceding example and being suitably restorable, is present. At the back the shutter structure, a space will be provided for the recovery of the material formed by the bullets that have gone through the septum and by the granules that are dragged along by the bullets; in this case, the recovery may be performed manually depending, however, on the amounts of material to be recovered. Fig. 5 shows an embodiment wherein the rear side of the septum S20 is defined by a shutter structure with slats 32, similarly to Fig. 3. On the front side, on which the bullets arrive, the septum is defined by another shutter structure, with more widely spaced slats 34 to reduce the percentage of bullets that may strike the slats edge; the slats 34 may have a limited inclination in respect to the incoming bullets trajectory, held within such limits as to prevent harmful phenomena taking place as a consequence of the possible impact of the bullets against the lower surface of the same slats. In any case, the bullet goes through the rubber panel, when present, and through the braking mass, as far as it encounters the plane determined by the tips of the slats, at a speed equal to or lower than the safety speed. The ogives which do not encounter the tip of the slats 23 or 32 will continue their run as far as they impinge against any surface, to be then easily collected. The bullets which might strike the tips of the slats will also be stopped and dragged out of the shutter by the bullets that would happen to pass in the immediate vicinity; a possible impact between two bullets will not create any inconvenience as it takes place at the safety speed. Above the shutter, the reservoir will provide, by gravity fall, for the restoration of the granules that the bullets may have dragged out of the knocking-down septum. What comes out of the knocking-down septum can be selected and recycled by various screening and handling devices. In the applications regarding small shooting ranges with poor activity, it is possible to procede by manual means. According to Figs. 5 to 9, a braking layer 41 is created, made of granulated material, which develops with the inclination of the angle of friction and is supported by a shutter structure 43 having a corresponding inclined development. The braking layer 41 of granulated material may consist of sand, granules of rubber or plastics, mixture of the same or similar materials, even of organic origin. The nature and the thickness of the layer will be such as to prevent the formation of lead oxides or powders upon the impact with the most advanced part of the shutter 43. The shutter structure 43 comprises a plurality of slats 431 being almost horizontal or slightly inclined downwards and in the direction of the bullets motion or in the opposite direction. It has the purpose of retaining the granulated material though permitting the coming out of the braking material and of the bullets, a suitably limited thickness of the layer 41 being established. The slats 431 of the shutter may have a particular shape, possibly with a set of sectors 433 (see Fig. 9) limiting the surfaces of the bullets exit. The assembly of the shutter 43 and of layer 41 makes up an energy knocking-down septum, thereby the bullets may escape from the rear part with limited residual kinetic energy, dragging along small quantities of granules as well as bullets possibly retained by the layer of granules. A set of damping and safeguarding diaphragms 45 is provided behind the knocking-down septum for intercepting the bullets which escape with still some kinetic energy. These diaphragms constitute, therefore, a safety measure, particularly useful for arms testing benches on which machine-guns with great shot frequency are tested and whose bullets - being fired at short intervals and striking the butt at the same point - may decrease the efficacy of the braking layer. The presence of the diaphragms is useful also in the case of relatively large bullets and/or of relatively powerful weapons. At the back of diaphragms 45, another inclined plane 47 is also provided, against which the expelled bullets and granules strike then to descend along the same plane with a dynamics to be explained herebelow. An elastic suspension 49 may be provided for supporting the inclined plane 47 and an underlying grate 51 being inclined like the plane 47 and solid therewith. Said grate 51 is apt to be crossed by the granules and to retain the bullets. Just upstream of the grate 51, a diaphragm 53 for loading the grate 51 is disposed, which at the same time provides for lowering the speed of the granules and bullets that slide downwards along the inclined plane 47. Numeral 55 indicates a bullets container made up of an overturnable basket, which is arranged for receiving what the grate 51 has retained. This basket - 55 as it rotates - performs the discharge down into an underlying container or a transverse conveyor belt 57. The horizontal conveyor belt 57 has the purpose of conveying the expelled granules, being screened by the grate 51, as far as a bucket elevator 59, with continuous or intermittent operation during the drill sessions, or even after the drill. In some cases, even a non mechanized handling may be provided if the granules quantity to be recycled is limited. At the end of the drill, the conveyor 57 may be used for transporting the bullets into a suitable container, by advantageously reversing the run direction and replacing the reception means of the same conveyor. The bucket elevator 59 is intended to convey the granulated material to a reservoir-lung 61. This elevator may be made up of a belt conveyor, a screw or similar machine. The reservoir-lung 61 will be able to contain even the whole braking mass of the layer 41 or - when architectural problems prevent this - only what is necessary for the apparatus operation. In the reservoir-lung, a lower screw 63 for the distribution in transverse direction of the granulated material during the drill, and an upper screw 65 for the distribution in transverse direction of the whole braking mass may be provided, in case the reservoir 61 is of corresponding capacity. At the bottom of the reservoir 61, a mobile gate 67 is provided, shaped as a horizontal shutter, which serves to adjust the thickness of the layer 41 and is able to cut off the communication between the reservoir-lung 61 and the formation zone of the layer 41. A lower gate 69 is also provided, which is intended to decrease the thickness of the layer 41 and to empty the butt unit by discharging the layer 41, for example onto the transverse conveyor 57; said gate is adjustable for dosing the discharge velocity. The illustrated elements are necessary for the running of a shooting range where drill with various types of weapons providing great shot intensity is performed. For more limited uses, some elements can be abolished, especially those relating to the handling of the granulated material falling on the plane 47. The bullets being shot, sink into the braking layer and thus some of them may escape directly from the knocking-down septum or layer 41 through the spaces between the slats 431. Other bullets, by impinging on the slat 431 (or on a septum 433, if any), stop in the mass of granules; this takes place also for the bullets that divert in the layer 41 and present themselves transversally disposed. In any case, the energy of the outcoming bullets will cause each time the expulsion of small quantities of the granulated material as well as of bullets contained therein, on the back side of the shutter. The phenomenon will repeat itself at each shot, so that a progressive advancement of the stopped bullets towards the exit from the knocking-down septum and thus their expulsion will take place, while the number of bullets instantly present in the layer 41 will get stabilized while time elapses. Only a limited fraction of the granules goes beyond the assembly of shutter 43 as a mixture of granules and bullets; this mixture falls on the inclined plane 47 and goes down along the same to be graded by the grate 51; the granulated material will reach the belt 57, the elevator 59 and finally the reservoir 61; the bullets will be collected into the basket 55, from which they will be moved away at the end of one drill or more drills. The possible residual energy of the bullets which get over the butt will be taken up by the assembly 45, 47 which will be made to vibrate and will result thereby apt to ease the dynamics of the operation. The described butt, therefore, operates by soft damping with a resorting of limited fractions of granules and restoration of the braking mass, without the use of regenerating motorizations, but by exclusively exploiting the gravity and the kinetic energy of the bullets and avoiding at the same time any form of progressive accumulating of bullets, that is, avoiding the formation of the so-called lead wall. The rotating basket 55 ensures the collection and then the discharge of the bullets. The elastic suspension 49 of the inclined plane 47 - with rubber buffers, silent-blocks, springs or other - exploits the residual energy of the bullets; in fact, this suspension has the purpose of enhancing the vibrations caused by the bullets upon their impact on the inclined plane 47 and which vibrations influence also the grate solid therewith. In this respect, it must be considered that for example a machine-gun, of a type in use has a frequency of 1000 shots per minute, with initial speeds of 980 m/s; a bullet of 7 g at the residual speed of 100 m/s - which is a safety speed at which it can come out when directly passing through the slot between two slats 431 - has a residual kinetic energy of 35 kgm and thus causes a vibration; the bullets coming out directly, besides causing knocks and the consequent vibration, determine as well the expulsion of a relatively small quantity of granules along with the bullets stopped therein. By varying the inclination of the slats and/or the thickness of the layer of granules, it is possible to vary the quantity of granules discharged by each bullet of a certain weight. In any case, during the same drill session, there is obtained the simultaneous and automatic resorting, that is, the separation of the braking granulated material and of the bullets, without any motorization. In Figs. 10 to 12, numeral 71 indicates the braking layer of granulated material, which is supported by the slats 731 of a shutter-like assembly 73. Behind the slats 731, damping diaphragms 75 are disposed which are similar to those indicated by 45. At the back of the diaphragms 75 the inclined plane 77 is disposed, which is similar to that indicated by 47 and which may be mounted with vibrating means like those indicated by 49. At the lower end of the shutter 73, a lower gate 81 is provided, which can be moved in its own plane (mostly a horizontal plane); this gate can be moved by a motorized rack system 83. The gate 81 is located above a hopper defined by the inclined plane 77 and by an opposite wall 77A. Below the hopper 77, 77A, a conveyor 85 is provided, which discharges the granulated material and the bullets collected and transported by the conveyor 85 into a sieve 87 capable of separating the bullets from the granulated material. The granulated material is delivered from a conveyor 89 to a bucket or similar elevator 91, having the same function as the elevator 59. Numeral 93 indicates a reservoir-lung similar to that indicated by 61, with which two screw distributors 95 and 97, similar to those indicated by 63 and 65, are combined. A gate 99 movable in its own plane has the functions of that indicated by 67, in order to adjust the thickness of the layer 71 in the upper part of the same. The gate 81 may be moved to adjust the thickness of the layer 71 in the lower part thereof and, in particular, to prevent the braking layer from increasing its thickness owing to landslips or slidings of the granulated material during the drill. In fact, in the arrangement shown in Fig. 12, the layer 71 is in the condition of not increasing its thickness owing to the fact that the surplus of granulated material, instead of piling up, discharges itself, according to the arrow f71, from the edge of the gate 81 which is on the left side, looking at Fig. 12. By moving the gate, it is possible to adjust the maximum thickness that the lower part of the layer 71 can take up. The gate 81 is also intended to allow the discharge of the granulated material for the emptying out of the layer 71, by moving the gate 81 to the left, looking at the drawing, beyond the position of Fig. 11. In fact, the material falls down from the right edge (looking at Fig. 11) of the gate 81 when it is displaced in the above mentioned manner, until the layer is exhausted, except for a residue of granulated material remaining on the slats. Other granulated material may be retained on the diaphragms 75 in substantially negligible amounts. In Figs. 13 to 15 the disposition below the gate 81 is shown modified, a separating grate 102 being provided, similar to that indicated by 51 to make the granulated material fall on an inclined plane 104 being below the granulated material which thus falls onto the conveyor 85; the bullets retained by the grate 102 fall therealong to be collected into a container 106 similar to that indicated by 55.

Claims: 1. Equipment with an energy knocking-down septum for bullets, to be installed in shooting ranges, with the intervention of a mass of granulated material, characterized in that it comprises a shutter structure with steel slats, on which granulated material is made to rest, which material, lying on the slats of the shutter structure according to the natural angle of repose, is retained by the same shutter which defines the exit side of the bullets. 2. Equipment according to claim 1, characterized in that the slats of the structure are substantially horizontal. 3. Equipment according to claim 1, characterized in that the slats of the shutter have the inclination directed upwards and towards the transit direction of the bullets. 4. Equipment according to the preceding claim, characterized in that the shutter is inclined as to result approximately parallel to the stability surface of the granulated material; the surface of the bullets entrance being developed with the inclination of the friction cone. 5. Equipment according to claim 4, characterized in that it comprises a diaphragm with a lower edge being mobile for changing the septum thickness by changing the discharge conditions from an overhanging hopper reservoir of the material. 6. Equipment according to claims 1 to 3, characterized in that the shutter is disposed with a development being less inclined - in respect to the vertical - than that of the friction cone, as far as to be even vertical; means being provided for retaining the braking mass in the front part. 7. Equipment according to claim 6, characterized in that said means comprise panels of rubber (even regenerated rubber) possibly reinforced with music wires, to define the bullets entrance surface; said panels being able to be individually replaceable. 8. Equipment according to claim 6, characterized in that said means comprise a further shutter structure. 9. Equipment according to claim 8, characterized in that the slats of the shutter structure of the bullets entrance are more widely spaced than those of the shutter structure on the side of the outcoming bullets. 10. Equipment according to claims 1 to 4, characterized in that said shutter structure has such a disposition that at least a part of the bullets go directly through the braking layer with a residual kinetic energy which causes also the backwardly expulsion of fractions of granules and of bullets being stopped in the layer; and in that on the back of the shutter structure, a surface is disposed for the interception and the falling along an inclined plane of the bullets and granules. 11. Equipment according to claim 10, characterized in that the intercepting surface is elastically mounted in order to vibrate owing to the residual energy of the bullets which are intercepted by said surface. 12. Equipment according at least to claim 10, characterized in that the intercepting surface is combined in the lower part with a classification grate for the separation of the granules from the bullets that are retained and delivered to a collector. 13. Equipment according to claim 12, characterized in that just upstream of the grate, a diaphragm is provided for retaining the material to be classified. 14. Apparatus according to claim 12, characterized in that in order to gather the material falling from the sieve, a transverse conveyor is provided located therebelow. 15. Apparatus according to claim 12 or 14, characte­ rized in that the bullets collector is overturnable for the discharge; said collector being able to discharge into said conveyor which can be reversed. 16. Apparatus according to claim 10 or 11, characterized in that at the intercepting surface, damping diaphragms vibrating therewith, are associated, being inclined upwards and in the direction of the bullets motion, in order to intercept them and dampen their kinetic energy. 17. Apparatus according to claim 10, characterized in that the slats are slightly inclined downwards and in the direction of the bullets motion. 18. Apparatus according to claim 10 or 17, characterized in that it comprises limiting sectors developed from the front edge of the slats downwards and in the direction of the bullets motion. 19. Apparatus according to the preceding claims, characterized in that, in order to adjust the thickness of the layer of the material supported by the shutter structure, gates are provided both upstream - that is in the upper part - and downstream - that is in the lower part - which move in their plane, mostly a horizontal plane. 20. Apparatus according to claim 19, characterized in that a lower gate substantially makes up the last of the slats, and can be moved in one direction or the other to increase respectively decrease the thickness, and can also reach a position in which it allows the almost complete discharge of the inclined layer supported by the shutter structure.

Inventors: BARINI, ALBERTO
Applicants: A.B.C. APPALTI BONIFICHE E COSTRUZIONI DI ELIO FLORIA & C. S.A.S.
Application year: 1986
Main classification: F41J1
IPC codes: F41J13