BULLET TRAP

Abstract: A bullet trap for a horizontally fired projectile (B) includes a passageway (13) bounded by upper and lower flat plates (13a, 13b), which may be inclined to the horizontal at an angle ( alpha , beta ) of between 0 DEG and 15 DEG and define an entrance opening (13c) and a shallow exit opening or throat (13d), and a horizontal generally spiral-walled spent projectile energy-dissipating chamber (15) which communicates substantially tangentially with the passageway through the throat. The circumferential chamber boundary wall (25) has an initial part (25a) which is an upwardly curving extension of the lower plate (13b) and a terminal part (25c) which is located at the rear end of the upper plate (13a). The low angles of inclination of the passageway boundary plates (13a, 13b) ensure that the projectile is gently deflected from its original path of flight and enters the chamber without being shattered by or damaging the circumferential boundary wall of the chamber. A liquid lubricant (27) may be sprayed against the initial part of the chamber wall to engulf and flush lead dust, if any is generated, and other solids into the passageway and thence into a collecting vessel (17), and may be recirculated to the spray head (26) in the chamber.

Description: BULLET TRAP Technical Field This invention relates to bullet traps, i.e., devices used to catch and stop bullets and like projectiles fired from rifles, shotguns, handguns, airguns, and the like in a firearm testing facility or a commercial firing range. Background Art Bullet traps per se are well known devices which have been used for many years by firearm manu- facturers and users (the latter including firing rang¬ es operated by military installations, police depart¬ ments, rifle and pistol clubs, and the like) who are faced either with the need to proof, function fire and target firearms such as handguns, rifles and shotguns or with the task of simply collecting spent bullets fired on the range. In this context, ' ■ proof" means test firing a firearm at a higher load of ammunition, usually 40% greater, than the regular load specified for the barrel of that firearm; "function fire" means test firing the firearm through its full cycle of functions; and "target" means test firing the firearm for accuracy. The objectives of such devices have been to provide means located at a relatively short distance from the shooter to catch the lead or other types of bullets (jacketed or unjacketed) and prevent either the ricochet of a whole bullet or a large frag- ment thereof or the backsplattering of numerous small metal particles, which could return with enough energy to cause injury to the shooter or innocent bystanders, and to collect the waste lead, brass and jacket ate- rial. The known types of bullets traps have run the gamut from wood boards to sand-filled boxes to metal¬ lic funnel and deceleration chamber combinations. Merely by way of example, a known sand-type bullet trap consists of a quantity of sand in a hardwood box set against a concrete backstop or wall. However, a bullet trap of this class has a number of drawbacks and disadvantages, both in terms of its structural and functional characteristics and in terms of the expenses associated with it. Apart from the material requirements (hardwood and sand) for the box over the course of a year, annual maintenance comes to about 8 man-hours per week for 50 weeks. Disposal of such a sand/wood trap and accumulated waste requires handling a load of about 15 tons per year, including transportation to a landfill. Assuming 5 to 6 loads per year, annual expenditures at current costs (in¬ cluding labor) come to at least about $30,000 plus the cost of the sand and hardwood, for an aggregate total of at least about $40,000. Moreover, under current environmental laws, lead has been banned from landfills unless it has first been treated to meet new disposal standards, and the separation of lead from the sand and the detoxification treatment thereof (e.g., a thermal oxidation, which has been proposed for this purpose) can easily double or triple the dis¬ posal costs. On the other hand, the mechanical bullet traps of the funnel and deceleration chamber type, which came onto the market about a century or so ago, were specifically designed to deal with some of the problems that were inherent to the sand-filled box types of traps. Some representative relatively simple bullet trap constructions of the funnel and chamber type are disclosed in U.S. Pats. Nos. 385,546 (Decumbus 1888); 694,581 (Reichlin 1902); 840,610 (Easdale 1907); 2,013,133 (Caswell 1935); and 4,126,311 (Wagoner 1978). Somewhat more sophisticated bullet trap constructions are disclosed in U.S. Pats. Nos. 2,772,092 (Nikoden 1956); 3,737,165 (Pencyla 1973); 4,512,585 (Baravaglio 1985); and 4,821,620 (Cartee et al. 1989). Of the first-mentioned set of these bullet traps, to the best of my knowledge none are in current commercial use, primarily because they were not de¬ signed for and were incapable of withstanding the im- pacts of high power steel-jacketed ammunition, but also because they tended to deteriorate rather rapidly even under the impacts of relatively low power ammu¬ nition. In essence, this was due not only to the fact that the steel or like metal of which the impact plates defining the funnel and the initial contact region of the deceleration chamber were made was gen¬ erally of a relatively low grade in terms of its com¬ position (carbon content, etc.) and strength, but also to the fact that the impact plates were generally ar- ranged at relatively high angles (30° to 60*) to the bullet flight path. Bullets coming into contact with such impact plates at high momentum and at relatively large angles invariably ricochet from one of the fun¬ nel impact plates to the other at relatively high angles of incidence and ultimately impact at a high angle against the interior surface of the circum¬ ferential boundary wall of the deceleration chamber and bounce along the same from point to point. This has not only resulted in a shattering and fragmenta- tion of the bullets but also in a relatively high rate of deterioration of the impact plates and the deceler- ation chamber wall and frequent occurrences of pene¬ tration thereof by the bullets or fragments thereof. The escape of a bullet or its fragments from confine¬ ment in the chamber, of course, further entails the danger of injury and even death to the shooter or an innocent bystander and also, where the bullets are made of lead, contributes to lead pollution of the environment. Even the more recent ones of the patented bullet traps, however, some of which, to the best of my knowledge, may currently be in use, have been beset by numerous drawbacks, including high original equip¬ ment manufacturing, installation and maintenance costs, the need for frequent replacement of baffle or impact plates which are damaged through scoring, ero¬ sion and penetration by bullet impacts, the need for minimizing lead build-up and for controlling the prob¬ lem of lead dust (airborne lead dust must be eliminat¬ ed using sophisticated vacuum systems) , and the need for dealing with hazardous waste (handling, collec¬ tion/separation, transportation and disposal) . More¬ over, such bullet traps are generally not multi-func¬ tional, i.e., they cannot be used to proof, function fire and target firearms in one system because their impact plates would be demolished by the high load ammunition used in proofing. Also, these traps are usually limited by their design for use with either handguns or high powered rifles but not both. Disclosure of the Invention It is an object of the invention to provide a novel and improved bullet trap by means of which the aforesaid drawbacks and disadvantages of the known bullet traps can be efficaciously avoided. It is another object of the invention to provide a bullet trap which is constructed to substan¬ tially eliminate high energy, high angle impacts of bullets against the walls of the trap so as to avoid bullet fragmentation and penetration of walls, to min¬ imize frictional contact between the bullets and the boundary wall surfaces of the trap for reducing scor- ing and erosion of those surfaces as well as the gen¬ eration of lead dust, and to automatically transfer spent bullets and bullet fragments, jackets and cas¬ ings, as well as any lead dust that may be formed dur¬ ing the passage of the bullets through the trap, out of the trap to a collecting vessel. Generally speaking, the objectives of the invention are attained by a bullet trap for catching and deenergizing a bullet fired along a substantially horizontal path of flight from a firearm, which trap (like many of the known traps) has a first pair of spaced flat plates located on opposite sides of the path of flight of the bullet and a second pair of spaced flat plates arranged transverse to the first plates on opposite sides of the bullet flight path, with the two pairs of plates defining the respective sides of a passageway having at its front end an en¬ trance opening and at its rear end an exit opening or throat through which the bullet can pass, and a spent bullet deceleration and energy-dissipating chamber the circumferential boundary wall of which is of generally spiral configuration and the opposite end walls of which are constituted by portions of the respective second plates, with the passageway communicating with the chamber substantially tangentially of the latter through the throat. In a trap of this general class, the basic improvement provided by the invention comprises the following features: (a) The two first plates are lo¬ cated, respectively, above and below the path of flight of the bullet and are oriented at respective angles of inclination to the horizontal ranging from 0* to about 15", with the structural and physical properties of the first plates, e.g., the nature and strength of the material of which the first plates are made, and the maximum angles of inclination within that range at which those plates are oriented relative to the horizontal, being a function in any given trap of the types and power ratings of the firearms and ammunition to be used with that trap; (b) the bullet deceleration and energy-dissipating chamber has a sub- stantially horizontal axis, and the circumferential boundary wall thereof is defined by a curved extension of the lower one of the two first plates, with (i) an initial part of the chamber wall extending from the lower first plate generally rearwardly of the passage- way first at an orientation to the horizontal substan¬ tially the same as that of the lower first plate and then arcuately upwardly relative to the latter, (ii) a middle part of the chamber wall extending arcuately from the initial part of the wall generally front- wardly of the passageway first upwardly and then downwardly, and (iii) a terminal part of the chamber wall extending arcuately from the middle part of the wall downwardly and again generally rearwardly of the passageway into substantially coplanar relation with the upper one of the two first plates and into overly¬ ing relation, at an end edge of the terminal part of the wall, to the region of the initial part thereof which is contiguous to the lower first plate; and (c) the chamber has no part the radius of curvature of which in the case of firearms and ammunition of the lowest power ratings is less than about 15.25 cm (6 inches) and in the case of firearms and ammunition of the highest power ratings is less than about 71.1 cm (28 inches) . Merely by way of example, a trap according to the invention which is designed for use with all types of manual firearms and all types of ammunition, regardless of the power thereof, would have the two first plates constructed of 1.9 cm (3/4 inch) thick high-tensile steel sheet and be a fairly large struc- ture, with its length (from the entrance opening of the passageway to the back of the deceleration cham¬ ber) being between 2.4 and 3.6 m (8 and 12 feet), its maximum height (measured vertically from the bottom edge of the trap, exclusive of the legs, to the top of the deceleration chamber) being between 1.8 and 2.4 m (6 and 8 feet), and its width being between 0.6 and 0.9 m (2 and 3 feet), with the angle of inclination of the two first plates to the horizontal being about 7 β , with the radii of curvature of the deceleration cha - ber wall parts being on the order of not less than about 71.1 cm (28 inches), and with the size of the entrance opening preferably being (depending on the width of the trap) either 61 cm by 61 cm (24 inches by 24 inches) or 91 cm by 91 cm (36 inches by 36 inches) . in contrast thereto, such a trap when designed for use with nothing more powerful than a .22 long ri¬ fle may be made of 0.48 cm (3/16 inch) thick high ten¬ sile steel sheet and may be 91.4 cm (36 inches) long, 71.1 cm (28 inches) high, and 33.0 cm (13 inches) wide, with the two first plates being inclined at an¬ gles of about 12" to the horizontal starting from a 33 cm by 33 cm (13 inches by 13 inches) wide entrance opening, and with the radii of curvature of the vari¬ ous parts of the deceleration chamber wall being on the order of not less than about 20.3 cm (8 inches). On the other hand, in the case of a trap designed for use with handguns which are more powerful than .22 long rifles but in any event not more powerful than a .44 Magnum, the trap may be made of 0.64 cm (1/4 inch) thick high tensile steel sheet and may be 127 cm (50 inches) long, 76.2 cm (30 inches) high, and 40.6 cm (16 inches) wide, with the two first plates being in¬ clined at angles of about 7" to the horizontal start¬ ing from a 40.6 cm by 40.6 cm (16 inches by 16 inches) entrance opening, and with the radii of curvature of the various parts of the deceleration chamber wall being on the order of not less than about 22.9 or 25.4 cm (9 or 10 inches) . In the case of a trap designed for use with air guns, the first plates of the trap actually need not be made of steel but may be made of suitable self-lu¬ bricating plastics or comparable materials, e.g., ny¬ lon, polyethylene, polypropylene, polyvinyl chloride, graphite, and the like, which may be fiber-reinforced and/or otherwise treated with suitable additives as needed for enhancing their integrity. The dimensions of such a trap, which may be a one-piece molded con¬ struction, may be basically the same as those of the smallest of the other traps described above, except that the elements constituting the two first plates may be inclined at angles of as much as about 15° to the horizontal and that the radii of curvature of the various parts of the deceleration chamber wall may be on the order of as little as about 15.25 cm (6 inch¬ es) . In the basic construction of the trap according to the invention, it should be emphasized, the initial part of the deceleration chamber wall is, for all practical purposes, the most important region thereof because it serves to overcome the bullet's resistance to a change in its direction of flight and out of its original straight ahead trajectory. It is to ensure that this occurs without either a fragmenta¬ tion of the bullet or a destructive scoring or pene¬ tration of the chamber wall, that the initial part of the latter has a radius of curvature of not less than an appropriate minimum value. This minimum value of the radius of curvature is empirically determined to be that which is appropriate to keep the maximum amount of the side of the bullet presented to the chamber wall during its travel along the initial part of the latter. In this way, the shock of the bullet is distributed more evenly along the wall and over a larger surface area thereof, and tumbling of the bul¬ let because of its nose digging into the chamber wall (which would occur were the radius of curvature of the wall of any given trap smaller than the minimum value appropriate for that trap) is prevented. It will be understood, therefore, that since it is highly desir¬ able to achieve the same effect along the entire circumferential chamber wall, the same is designed so as to have at no part thereof a radius of curvature smaller than the appropriate minimum value. An equally very important aspect of the in¬ vention is the orientation of the two upper and lower plates (the first plates) of the passageway at re- spective very low angles to the horizontal ranging, as previously mentioned, from 0 β to not more than about 15". Actually, it would be preferable for the purposes of the invention for the bullet to fly straight down the passageway and to enter the deceleration chamber through the throat or exit opening of the passageway and to come into contact with the relatively gently sloping initial part of the circumferential wall of the chamber without having previously contacted or impacted against any other surface. However, that is an extremely unlikely occurrence, and in actual prac¬ tice a bullet fired into the trap through the entrance opening will in the ordinary course of events come into contact with one or the other of the two first plates, normally the lower one. By virtue of the construction of the pas¬ sageway with a low angle orientation of the upper and lower plates thereof (the term "low angle" here should be interpreted with respect to the power of the fire¬ arm being used, so that a 15° angle of inclination is low if the firearm is an air gun while a 7" angle is low if the firearm is a high-powered rifle), when a bullet or like projectile on a substantially horizon¬ tal flight path impacts against either the upper or the lower plate, it will rise off that plate by an angle of about 1° or so and will then fly practically along the surface of the plate directly into and through the throat of the passageway. The contacted passageway plate thus acts not as a barrier tending to interrupt the flight of the bullet along its original path by having it rebound violently from the plate at a high angle, which a high angle impact plate of the known traps would do, but rather as a deflection plate tending to change the direction of flight only slight¬ ly. The excess of the resultant angle of orientation of the bullet flight path over that of the contacted deflection plate is due to the "bounce factor" of the bullet, which in essence depends on its ballistics (primarily the angle of contact with the plate) and its physical properties (weight, shape, length, etc.). After being deflected by the contacted plate, the bul- ι e t continues its flight along a path leading slightly away from that plate but not angled sufficiently rela¬ tive thereto to cause the bullet to contact the other plate, thereby passing cleanly through the throat or exit opening of the passageway. Ultimately, the bullet comes into contact with the initial part of the circumferential boundary wall of the deceleration chamber approximately where that wall begins to slope upwardly relative to the lower plate. At that contact point, the angle of incidence is relatively low, so that the bullet is deflected from its straight ahead path into a curved path. At that time, the large radius of curvature of the cham¬ ber wall comes into play (the term "large radius" here should also be interpreted with respect to the power of the firearm, so that a 15.25 cm (6 inches) radius is large when the firearm is an airgun while a 71.1 cm (28 inches) radius is large when the firearm is a high-powered rifle) and results in the arcuate path of the bullet effectively hugging the chamber wall and reversing its direction. As a consequence, the risk of damage (erosion and penetration) by the bullet to the upper and lower plates of the passageway structure and to the initial part of the circumferential chamber wall is greatly minimized and the useful life of the trap is substantially enhanced. it bears repetition, in this regard, that the term "impact" as applied to the trap according to the invention is used herein to designate contacts be¬ tween a bullet and the trap walls which occur at rela¬ tively low angles and result in low angle deflections of the bullet from its path without appreciable frag¬ mentation, as distinguished from the high angle con¬ tacts that occur in the known traps where the bullet is in effect stopped dead in its tracks and merely rebounds from the walls at a high angle and is usually shattered into fragments. Once the bullet is in the deceleration cham¬ ber and is there urged out of its straight ahead tra¬ jectory into one following the circumferential bound¬ ary wall of the chamber, of course, the bullet circum- navigates the chamber with gradually decreasing speed while remaining in contact with the circumferential boundary wall thereof until the energy of the bullet has been substantially dissipated. It is immaterial whether or not this requires more than one turn around the entire circumference of the chamber; ultimately, the bullet falls from the terminal part of the circum- ferential chamber wall over the end edge thereof onto the region of the initial part of the wall just rear¬ wardly of the throat of the passageway and slides or rolls through the throat back into the passageway and along the lower first plate for removal from the trap. In this regard it should be noted that, al¬ though the stated 0" to 15" range of the angular ori¬ entation of the upper and lower plates of the passage¬ way to the horizontal is applicable to any bullet trap according to the invention, there are practical con¬ siderations which make it advisable to utilize an ori¬ entation in the upper part of the range, i.e., between 7° and 15° in all cases. Actually, if the trap were to be used only in conjunction with function firing or proof testing of a firearm, the upper and lower plates of the passageway could actually both be oriented sub¬ stantially horizontally, i.e., either at a 0" angle of inclination to the horizontal and hence precisely parallel to each other, or at an angle of perhaps l β or 2° to the horizontal and converging toward one an¬ other in the direction of flight of the bullet. Be¬ cause the throat leading into the deceleration chamber is relatively shallow, however, for example, about 5.1 to 6.4 cm (2 to 2.5 inches) in height, the orientation of the upper and lower plates of the passageway at angles in the lower end region of the stated range necessarily means that the height of the entrance opening of the passageway will also be very small. This would be of no consequence to the performance of the function firing or proof test, because for those purposes the muzzle of the firearm can be located very close to and actually even at or within the entrance opening of the trap, so that the likelihood of the bullet missing the entrance opening is effectively nil. However, the trap according to the invention is also to be used for target testing a firearm. For that purpose, the test firing stand supporting the firearm usually is located at a much greater distance from the entrance opening of the trap, e.g., 22.9 to 27.4 m (25 to 30 yards) away, in order to let the bul¬ let stabilize in its path of flight prior to arriving at the trap. At that distance, the risk of the bullet missing a very narrow entrance opening is sufficiently great to make it advisable to provide a larger en¬ trance opening. It is for this reason that the upper and lower plates of the passageway are preferably ar¬ ranged at an angle of at least 7 ' to the horizontal, which in the case of a trap 3.05 to 3.66 m long (10 to 12 feet) provides an entrance opening the height of which is about 76.2 to 91.4 cm (30 to 36 inches). Thus, even if the flight path of the bullet is not true and precisely horizontal, the bullet will none¬ theless enter the passageway because the entrance opening of the funnel-shaped passageway is sufficient¬ ly large to compensate for slight deviations in its trajectory. In accordance with a further aspect of the invention, any bullet trap of this type which is in- tended to be used with lead bullets is equipped with a spray nozzle arrangement in the deceleration chamber for directing a spray of a liquid lubricant, prefera¬ bly a white water lubricant of a commercially avail¬ able type consisting of, for example, 4 parts water and 1 part mineral oil, against the interior surface of the circumferential boundary wall of the decelera¬ tion chamber. Preferably, the spray is directed against the initial part of the wall somewhere in the zone between the three o'clock and five o'clock posi- tions, for example, at the three-to-four o'clock posi¬ tion. The lubricant thereby flows downwardly over that portion of the chamber wall, enters the passage¬ way through the throat thereof, and then flows along the lower first plate to a discharge location, prefer¬ ably adjacent the front end thereof, ultimately drop- ping down into a collecting vessel, for example, a steel drum with a capacity of 208.175 liters (55 gal¬ lons) , located below a suitable opening provided in the front end region of the lower first plate. The liquid thus serves multiple functions. On the one hand, it lubricates both the lower first plate of the passageway structure and the initial part of the deceleration chamber boundary wall and at the same time applies a coating of lubricant to the bul¬ lets fired into the trap and coming into contact with the lower first plate, thereby minimizing the metal to metal contact between the bullets and the metal sur¬ faces along which they move, with the result that scoring and erosion of those surfaces as well as the generation of lead dust, if the bullets are made of lead, are reduced as far as possible. (Because the metal to metal contact between the bullets and the trap surfaces can never be completely eliminated, even with a lubricant coating the surfaces, the generation of lead dust can also not be completely eliminated.) On the other hand, the liquid serves as a flushing agent through the intermediary of which shells, cas¬ ings, spent bullets, any lead dust that is generated, and even any lead fragments of a larger size that might split off from the bullets, are engulfed in the liquid and are flushed thereby along the lower first plate of the passageway and enter the collecting ves¬ sel together with the liquid. Escape of lead dust (atomized lead) into the environment and potential health hazards which that would pose are thus effec- tively avoided. Still further functions will become apparent as the description proceeds. In accordance with yet another aspect of the invention, the spray nozzle system in the bullet de¬ celeration chamber, which may be in the form of a 2.54 cm (l inch) diameter conduit extending generally par- allel to the horizontal axis of the chamber along the full length of the latter and having a plurality of holes or orifices with diameters of 0.79 cm (5/16 inch) provided therein along its entire length, is interconnected with the collecting vessel by suitable piping, and a pump is incorporated in the piping, so that the lubricating liquid can be recirculated from the collecting vessel to the spray nozzle conduit. Preferably, the piping is connected to the collecting vessel in an upper region thereof but in any event at a substantial elevation above the bottom of the ves¬ sel. This ensures that the liquid lubricant which is extracted from the collecting vessel by the pump for recirculation to the spray nozzles is free and clear of solids accumulated in the collecting vessel, because the solids, being considerably heavier than the liquid, will tend immediately upon their entry into the collecting vessel to sink to and settle on the bottom thereof. The liquid thus is automatically self-cleaned, preventing recirculation of lead dust or any other solids to the deceleration chamber. In accordance with a further feature of the invention, the collecting vessel is also provided across its entire expanse near the top thereof with a sieve or strainer member. Preferably, the sizes of the openings of the strainer member are such that they will permit any lead dust entrained in the lubricating liquid to pass through the strainer member but will not permit larger metal particles or shells or casings to pass through. Thus, only lead dust will accumulate on the bottom of the collecting vessel while larger objects will be retained on the strainer member. It should be understood, in this regard, that if the trap is to be used only in connection with low power air guns firing non-lead steel pellets or BB's, the upper and lower deflection plates need not be made of high strength steel but can, as previously pointed out, be made of suitable plastics and like materials. Moreover, such a trap also does not have to be (although it may be) equipped with a liquid lu¬ bricant spray and flushing system because, given the nature of the bullets or projectiles fired from air guns, there is obviously no risk of lead dust being generated. At the same time, of course, the self-lu¬ bricating nature of the structural material of which the deflection plates and the circumferential wall of the deceleration chamber are made ensures that fric- tional interaction between the structural parts of the trap and the pellets is minimized. The advantages of the bullet trap according to the invention are manifold. Very significantly, the trap is relatively inexpensive to manufacture, can be constructed for transportability and ease of installation, and does not require the provision of thick walls, sand mounds or like back-up structures. Also, the trap is multi-functional and permits proofing, function firing and targeting of handguns, shotguns and rifles (including high-powered rifles) in one system, so that expenses that might have to be incurred in connection with the known types of bullet traps for providing duplicate separate systems for function firing, targeting and proof testing (the lat¬ ter, in addition to everything else, would normally require much stronger impact plates and a more heavily armored deceleration chamber) can be avoided. More¬ over, whereas for safety reasons high-powered rifles conventionally are test-fired only at outdoor long¬ distance firing ranges, the use of the bullet trap according to invention permits test-firing of such ri¬ fles to be safely performed even in a relatively small room with a distance of only 22.9 m (75 feet) or less between the muzzle of the gun and the trap. Aiming of the rifles may further be facili¬ tated by the provision, according to another feature of the invention, of a band arranged for longitudinal movement thereof across the entrance opening of the passageway structure and having a plurality of target regions defined on its surface facing the test firing stand. Appropriate movement of the band, which may be effected manually or remotely with the aid of a suit¬ able electric motor or the like, thus enables a target region thereof to be selectively positioned in front of the entrance opening. Still further, the trap according to the in¬ vention, when made of appropriate materials and having its upper and lower deflection plates oriented at an appropriate angle of inclination to the horizontal, can withstand even such high energy ammunition as 30.06 NATO armor-piercing bullets, 600-grain elephant gun bullets, and the like. As a consequence thereof, wear and tear on the trap, maintenance requirements, and the need for periodic replacement of parts of the trap (in particular the upper and lower impact plates of the passageway and the circumferential boundary wall of the deceleration chamber) and the attendant costs thereof are all greatly reduced if not eliminat¬ ed altogether. Merely by way of example, a representative construction of such a trap designed for use with high-powered firearms utilizes a ramp angle (the angle of inclination of at least the lower first plate of the passageway) of about 7° to the horizontal and a radius of curvature of the initial part of the circum¬ ferential wall of the deceleration chamber of not less than about 71.1 cm (28 inches), with the ramps and the circumferential deceleration chamber boundary wall be¬ ing made of 0.95 cm to 1.9 cm (3/8 inch to 3/4 inch) thick high tensile steel sheet (70,000 psi minimum), with a thicker sheet being preferred for longevity if the firearms being tested shoot armor-piercing bullets or 600-grain elephant gun bullets. A particular make of such steel sheet which is found well suited for use in the trap of the present invention is available com- mercially under the trade names "Core 10" and "Tri 10". The side walls of the trap, covering both the passageway and the deceleration chamber, are made of 0.47 cm (3/16 inch) thick mild steel sheet. In such a trap, neither perforation nor erosion or scoring of the contact surfaces is found to occur over lengthy periods of continued use of the trap even for proof testing. Yet another advantage accruing from the trap of this invention is that, when a liquid lubricant flushing system is used, the lubricating fluid moves through an essentially closed and self-contained sys¬ tem, so that it basically requires nothing more by way of maintenance than a periodic replacement of any wa¬ ter that may have evaporated over time. In this con- nection, the lubricant circulation system of the trap provides an additional advantage in that it enables dispersion of lead dust into the environment to be inhibited. Thus, when a bullet is fired into the trap, any lead dust generated in the course of the movement of the bullet along the metal surfaces of the initially encountered impact plate and the subsequent¬ ly encountered circumferential wall of the decelera¬ tion chamber is inevitably, and without any possibili¬ ty of escape from the system, engulfed by and en- trapped in the liquid lubricant sprayed out of the spray nozzles and continuously flowing downwardly over the chamber wall and from there on over the lower plate of the passageway. As a consequence, the lead dust is flushed by the liquid into the collecting ves¬ sel, where it settles out of the liquid and accumu- lates on the bottom of the vessel. Accordingly, since liquid from the passage¬ way continuously enters the collecting vessel at sub¬ stantially the same rate as it is extracted therefrom by the circulating pump, the accumulated mass of lead dust in the bottom of the collecting vessel always remains submerged in the portion of the liquid located in the vessel and hence cannot be dispersed from the vessel into the surrounding atmosphere. On the other hand, when enough lead dust has accumulated in the collecting vessel to make it appropriate to do some¬ thing with it, for example, to recycle it for further use in making bullets, the circulatory piping is dis¬ connected from the vessel and the latter can then be simply removed as is, i.e., with all its contents, and replaced by a different one while the extraction of the accumulated lead from the liquid is effected under suitable anti-pollution precautionary measures. The so-achieved salvaging of the heretofore normally wast¬ ed lead dust for reuse thus provides an economic bene- fit as well, which has not been achievable with any of the known bullet traps. Brief Description of the Drawings The foregoing and other objects, character¬ istics and advantages of the invention will be more clearly understood from the following detailed description thereof when read in conjunction with the accompanying drawings, in which: Fig. 1 is a longitudinal vertical section through a bullet trap according to the invention; Fig. 2 is a front end elevational view of the trap with some parts being broken away and illus- trated in section to show details, the view being tak¬ en along the line 2-2 in Fig. 1; and Fig. 3 is a sectional view taken along the line 3-3 in Fig. 1. Modes for Carrying Out the Invention Referring now to the drawings in greater detail, the bullet trap 10 according to the invention is shown as including, between a pair of spaced elon¬ gated vertical side walls 11 and 12, a passageway structure 13 having upper and lower walls 13a and 13b and into the front end entrance opening 13c of which a projectile B, either a powder-discharged bullet or a BB, can be fired from a firearm (not shown) supported on a suitable test-firing stand (not shown) but including an aiming tube T the inner diameter of which is about 7.6 cm (3 inches) less than the height of the entrance opening 13c. The trap further includes at its front end a target positioning means 14 and at its rear end a generally spirally configured spent bullet deceleration and energy-dissipating chamber 15 the interior of which communicates substantially tangen¬ tially thereof with the interior of the passageway structure 13 through a shallow exit opening or throat 13d of the latter. The chamber 15 is shown as being equipped with a suitable spray nozzle means 16 for spraying a liquid lubricant onto a selected region of the interior wall surface of the chamber, although, as previously pointed out herein, in a trap made of self- lubricating plastics or the like and designed for use with air guns only, such a lubricant spray system is not necessary and can be dispensed with. A collecting vessel 17 for receiving liquid lubricant (if any) and solids discharged from the chamber and passageway structure is arranged under the lower wall 13b of the passageway structure at a suitable discharge location (e.g., adjacent the front end) thereof, and, when a spray system is used, a piping arrangement 18 incorpo¬ rating a pump P is provided between the collecting vessel 17 and the spray nozzle means 16 for feeding liquid lubricant from the collecting vessel to the spray nozzle means. The side walls 11 and 12 of the trap 10 (previously referred to herein as the second plates) are connected in any suitable manner at a plurality of longitudinally spaced locations (three are illustrated and have been found to be sufficient) to the opposite ends of respective horizontal cross beams 19, 20 and 21. Of these, the beams 19 and 21 are connected to and supported by respective pairs of vertical legs 22, 22a and 23, 23a adapted to stand on a suitable sup- porting surface S, for example, the ground or a floor of a room or basement of a building. Additional ri¬ gidity is imparted to the side wall structure of the trap by a pair of right triangular vertical stiffening plates 19a, 19b which are connected to the cross beam 19 and the proximate regions of the side wall plates 11 and 12, and by a rectangular vertical stiffening plate 20a which is connected along one longitudinal edge thereof to the cross beam 20 and at its opposite end edges to the proximate regions of the side wall plates 11 and 12. The upper and lower walls 13a and 13b of the passageway structure 13 of the trap (previously re¬ ferred to herein as the first plates) are connected at the respective opposite side edges thereof to the in- wardly directed faces of the side wall-forming plates 11 and 12. The plates 13a and 13b are located above and below, respectively, the horizontal path of flight X of the projectile B. In the illustrated embodiment of the invention, the plates 13a and 13b are shown as being oppositely inclined relative to the horizontal at respective angles α and β and as converging toward one another from the front end region 10a of the trap toward the rear end region 10b thereof, i.e., in the direction of flight of the projectile. The plates 13a and 13b thereby define a generally funnel-shaped pas- sageway structure having a relatively wide entrance opening 13c at the front end and a relatively shallow throat or exit opening 13d at its rear end. The an¬ gles of inclination a and β of the plates 13a and 13b, depending on the nature of the trap as determined by the types of firearms and ammunition with which it is designed to be used, lie between 0 s and about 15° to the horizontal and preferably (but not necessarily) are equal to each other. The deceleration chamber 15 of the trap 10, which has a horizontal axis, is located generally rearwardly of the passageway structure 13 and is de¬ fined between respective portions of the side wall- forming plates 11 and 12 in the rear end region 10b of the trap and a circumferential boundary wall 25 con- nected at its opposite side edges to the plates 11 and 12. The wall 25 in the illustrated embodiment of the trap is an extension of (i.e., of one piece with) the lower plate 13b of the passageway structure and has a generally spiral configuration. In essence, the chamber wall 25 may be con¬ sidered as having three distinct parts: (i) an ini¬ tial part 25a which extends from the throat 13d gener¬ ally rearwardly of the passageway structure, first at an angle of inclination to the horizontal substantial- lv the same as that of the lower plate 13b, as shown at 25a', and then arcuately upwardly relative thereto, as shown at 25a"; (ii) a middle part 25b which extends arcuately from the initial part 25a generally front- wardly of the passageway structure, first upwardly, as shown at 25b', and then downwardly, as shown at 25b"; and (iii) a terminal part 25c which extends arcuately from the middle part 25b downwardly and generally rearwardly of the passageway structure into substan¬ tially coplanar relation, as shown at 25c', with the upper plate 13a of the passageway structure and has an end edge 25c" overlying the region 25a' of the initial part of the circumferential boundary wall 25 contigu¬ ous to the lower plate 13b but spaced from that region by about 3.8 cm to about 7.6 cm (about 1.5 inches to about 3 inches), i.e., at least the same as the height of the throat 13d of the passageway structure 13. Of especial significance, in this connec¬ tion, is the fact that, depending on the nature of the trap and the types of firearms and ammunition with which it is designed to be used, no part of the cir- cumferential boundary wall 25 of the deceleration chamber 15 has a radius of curvature of less than an appropriate predetermined minimum magnitude. The min¬ imum magnitude of the radius of curvature in each case is empirically determined as being appropriate for the circumferential wall of the respective deceleration chamber so as to enable the same to function as a de¬ flection plate for relatively gently turning the pro¬ jectile B out of its pre-contact straight ahead tra¬ jectory to a curving path actually reversing its ini- tial direction of flight, as indicated by the arrows X-l, X-2 and X-3 in Fig. 1. Thus, as previously men¬ tioned, in a trap designed, for example, for use with airguns only, the radius of curvature may be fairly small but should not be less than about 15.25 cm (6 inches) , whereas in a trap designed for use with some¬ what more powerful firearms but in any event nothing more powerful than a .22 long rifle, the radius of curvature should not be less than about 20.3 cm (8 inches) . On the other hand, in a trap designed for use with handguns which are more powerful than a .22 long rifle but not more powerful than a .44 Magnum, the radius of curvature should not be less than about 22.9 cm (9 inches) or 25.4 cm (10 inches). In a trap designed for use with firearms more powerful than a .44 Magnum, however, such as, for example, high power rifles and shotguns, the radius of curvature should not be less than 71.1 cm (28 inches). It will be un¬ derstood, of course, that the radii of curvature of some regions of the wall 25 of any given deceleration chamber may be somewhat greater than the radius of curvature of one or more of the other parts of the wall, although it is not anticipated that the devia¬ tion from the stated minimum value of the radius of curvature in any given case will be more than about 10 to 15%. The spray nozzle means 16 (Figs. 1 and 3), which will be used in any bullet trap designed for use with lead bullets, i.e., ammunition that is likely to lead to the generation of lead dust, for directing sprays or streams 27 of white water lubricant against the interior surface of the circumferential boundary wall 25 of the deceleration chamber 15 comprises a conduit or pipe 26 securely mounted at one end region 26a thereof in the side wall 11 and extending across almost the entire length of the chamber substantially parallel to the horizontal axis of the same. An open¬ ing 28 is provided in the side wall 12 of the trap generally at the level of the conduit 26 to permit access to the latter and to the interior of the cham¬ ber 15 for cleaning, repairs, etc., the opening being normally closed and sealed by a door or cover plate 29. The conduit 26 is provided with a series of ori¬ fices or nozzles 26b spaced from one another longitu¬ dinally of the conduit and facing toward the initial part 25a of the circumferential boundary wall of the chamber. While the exact positioning of the nozzles is not critical, it is preferred that they be arranged to direct the streams 27 of the liquid lubricant against the initial wall part 25a somewhere in the zone between the 3-o'clock and 5-o'clock positions, for example, at the zone between the 3-o'clock and 4- o'clock positions as indicated diagrammatically in Fig. 1. The liquid lubricant is initially contained in the collecting vessel 17 and is fed therefrom to the conduit 26 via the piping 18, which is connected to the vessel 17 in its upper region by means of a fitting 18a, and the pump P incorporated in the pip¬ ing. The collecting vessel, e.g., a steel drum, in the illustrated embodiment of the invention is located below the front end region 13b' of the lower plate 13b of the passageway structure 13, under a discharge chute 30 which communicates with the bottom outlet opening 31a (Fig. 2) of a trough 31 extending across the entire width of the front end region 10a of the trap, the trough being connected at its opposite ends to the side walls 11 and 12 of the trap and at its upper edges to the underside of the plate 13b and thus having its upper intake opening 31b located directly below a 5 cm (2 inches) or so wide slot-shaped opening 32 provided in the plate 13b. Alternatively, the col- lecting vessel may be located directly under the lower plate 13b within the confines of the trap and between the legs 23, 23a (not shown). In either case, a re¬ movable sieve or strainer member 33 is located in the upper region of the collecting vessel, preferably somewhat below its top rim, the openings of the strainer member being large enough to permit passage of liquid and of lead dust therethrough but small enough to cause bullets, large bullet fragments, shells and casings to be retained thereon. In the illustrated embodiment of the trap, the target positioning means 14 is shown as including a pair of upper arms 36 and a pair of lower arms 37 which are secured, in any suitable way, either perma¬ nently as by welding, riveting or other manner of bonding or removably as by means of suitable fasteners such as screws or nuts and bolts (not shown) , to the outer surfaces of the side wall plates 11 and 12. The two pairs of arms are provided with journals or bear¬ ing means (not shown) for rotatably supporting the opposite ends of respective rolls 38 and 39 between which extends a band 40 of sheet material (e.g., pa¬ per) . The band is wound on the rolls, with its oppo¬ site ends connected to the same, and is provided on that surface thereof which in the region between the rolls faces away from the trap and toward the shooter, with a multiplicity of target images 40a (only one is shown in Fig. 2) . One of the rolls 38 and 39 is pro¬ vided with drive means (not shown) for rotating it so as to enable the band to be drawn from the idler roll and wound up on the driven roll for the purpose of shifting a fresh target image into position in front of the entrance opening 13c of the passageway struc¬ ture 13. The drive means for rotating the driven roll and advancing the band may be manually operatable, e.g., a crank handle connected to the roll axle, or remotely operatable, e.g., an electric motor connected (with or without suitable gearing) to the roll axle and adapted to be actuated by the shooter. Alter¬ natively, of course, target image-bearing boards or panels may be individually disposed in place in front of the entrance opening, e.g., with the aid of a stand or by hanging from the upper passageway plate 13a or otherwise (not shown) . The change in its flight path X which the projectile or bullet B will undergo after impacting against the lower plate 13b of the passageway struc¬ ture 13 is diagrammatically illustrated in Fig. 1. Assuming that the initial flight path X is substan¬ tially horizontal, when the projectile impacts at some point A-l against the plate 13b, it is deflected away therefrom, as indicated by the dot-dash line X', at a very small angle of about 1* or so to the lower plate 13b. Thus, whether β is 7*, 12* or 15 β , the angle of inclination of the path X' to the horizontal is only about 1* more, i.e., about 8°, 13* or 16*, so that, as shown, the projectile never contacts the upper plate 13a and instead passes directly through the throat 13d of the passageway. It then comes into contact at point A-2 with the gently upwardly sloping region 25a" of the initial part 25a of the circumferential bound¬ ary wall 25 of the deceleration chamber 15. Both these impacts are at such relatively low angles that the risk of damage or destruction of the plates 13a/13b and the initial part of the chamber wall 25 is effectively minimized. The same result would, of course, be achieved if the projectile were to contact the upper plate 13a, except that the path X' would then angle down from the plate 13a. As previously mentioned, in the presently contemplated best mode of practicing the invention, the upper and lower plates 13a and 13b of the passage- way structure 13 are inclined at respective angles of up to about 15* to the horizontal. It should be understood, however, as previously pointed out herein, that it is also within the contemplation of the pres¬ ent invention that the angle of inclination of either or both of the plates 13a and 13b to the horizontal may be much smaller. For example, an orientation of the upper and lower plates of the passageway structure 13 at angles of inclination α and β as small as about 1* or 2* is even more effective in avoiding a shatter- ing of projectiles upon impact than an orientation at a 15° angle or a 7* angle. Actually, an angle of in- clination of 0* (at which the plates 13a and 13b, strictly speaking, are not inclined but rather are parallel to the horizontal and each other) is still better from the standpoint of avoiding shattering of the projectiles, because of the greater possibility that a properly aimed projectile fired into the pas¬ sageway structure will travel straight through the latter and into the deceleration chamber without con¬ tacting either of the upper and lower -plates 13a and 13b. The utilization of such low-angle orienta¬ tions of the upper and lower impact or deflection plates of the passageway structure is, nonetheless, counterindicated by practical considerations. To be- gin with, it must be kept in mind that the desired height of the throat or exit opening 13d of the pas¬ sageway structure 13 is about 3.8 cm (1.5 inches) to about 7.6 cm (3 inches) at most, and preferably not more than about 5.1 cm (2 inches). As a consequence, an orientation of the plates 13a and 13b at angles of inclination of 2" or less would entail providing an entrance opening for the passageway structure almost as small as the exit opening. Thus, assuming the length of the passageway to be 91.4 cm (36 inches) from the entrance opening 13c to the exit opening 13d thereof, and assuming the throat to be 5.1 cm (2 inch¬ es high) , then positioning the upper and lower pas¬ sageway plates 13a and 13b at an angle of inclination of either 1* or 2* to the horizontal would provide an entrance opening of a height of about 8.3 cm (3.25 inches) or about 11.4 cm (4.5 inches), which would leave very little margin for error in the aiming of the firearm. Positioning the muzzle of the firearm being fired almost directly adjacent, or even in, such a small entrance opening 13c of the passageway struc¬ ture would, of course, minimize and perhaps even to- tally eliminate the risk of the bullet missing that opening. However, even though such a positioning of the firearm might well be tolerable for purposes of proofing or function firing of the firearm, it would not be an acceptable practice for the purpose of tar¬ get testing, which requires that the muzzle of the firearm be located a substantial distance, e.g., at least about 22.9 m (75 feet), from the bullet trap to enable the projectile to stabilize as it moves in its path of flight before it reaches the location of the target in front of the trap. It is these considerations, therefore, which make it preferable to orient the upper and lower plates 13a and 13b of the passageway structure at an- gles of inclination of up to 15* to the horizontal. At a 12* or 15* angle of inclination of the two plates of a 0.91 (3 feet) long passageway structure 13 ter¬ minating in a 5.1 cm (2 inches) high throat, the entrance opening is approximately 43.9 cm (17.3 inch- es) or 54.1 cm (21.3 inches) in height. By the same token, at a 7* angle of inclination of the two upper and lower plates of a passageway structure 13 which is 3.05 m (10 feet) or 3.66 m (12 feet) long, the height of the entrance opening is about 76.2 cm (30 inches) or 91.4 cm (36 inches). As a result, the risk of the projectile missing the passageway altogether even when the firearm is being targeted is effectively eliminat¬ ed. It will be apparent from the foregoing that the term "angle of inclination" as used in this appli¬ cation is intended to designate, and should be inter¬ preted as designating, any orientation of the plates 13a and 13b at an angle within the range of 0* to 15* to the horizontal. It will be understood, therefore, that when a projectile B is fired into the trap 10 and impacts against one of the passageway boundary plates, for example, against the lower plate 13b of the passageway structure 13, it will lose a small part of its energy by virtue of that first contact. Thereafter, the pro- jectile continues substantially unimpeded into the deceleration chamber. It should be noted, however, that although in any trap according to the invention which is made of metal and is equipped with a liquid lubricant spray and circulating system, the presence of the lubricant in the passageway and the decelera¬ tion chamber does serve to reduce to a great degree the frictional metal to metal contact between the pro¬ jectile and the plate or plates it contacts, it does not eliminate frictional effects altogether. Accord- ingly, where the projectile is a bullet made of lead (as probably 90% of all powder-discharged bullets are) , there will be a certain amount of lead dust gen¬ erated which, were it to escape into the atmosphere, would pose a major health and environmental hazard. However, because that lead dust is simultaneously with its formation engulfed in the flowing liquid lubricant and entrained thereby to move therewith toward the collecting vessel 17, the lead dust cannot escape. Moreover, as the lubricant flows into the vessel 17, the lead dust, being considerably heavier than the liquid, almost immediately settles to the bottom of the vessel and accumulates there, as indicated at 34. This action, as can be seen, has two direct and highly advantageous consequences apart from the ecological benefit mentioned above. One is of opera¬ tional significance, in that the quantity of liquid located in the vessel 17 above the accumulated lead dust 34 is effectively self-cleaned, and thus when the liquid is extracted from the upper region of the ves- sel and recirculated through the piping 18 and the pump P to the spray nozzle means 16, it does not con- tain any lead dust and clogging of the pump and the orifices or nozzles 26b is avoided. The other is of economic significance, in that the system provides an automatic conservation and salvaging of the lead dust as a raw material. Thus, when enough lead dust has accumulated in the collecting vessel to make it appro¬ priate to remove it, the pump is deactivated, the fit¬ ting or valve cock 18a is closed, the piping is dis¬ connected therefrom, and the vessel is covered and sealed, preferably after the strainer member and its accumulated debris have been removed, and is trans¬ ported to a suitable location where, under appropriate environmental safeguards, the lead dust can be sepa¬ rated from the liquid remaining in the vessel and pro- cessed for reuse in manufacturing bullets. It is worthy to note, at this point, that in any bullet trap according to the invention which is made of metal, the confinement of the lead dust to the interior of the trap and to the path of flow of the stream of liquid lubricant is assured by the welding of the various plates 11, 12, 13a and 13b/25 to each other which, apart from serving to rigidify and strengthen the structure of the trap, also provides the same with liquid-tight seals at all junctures be- tween the plates. On the other hand, in any trap made of plastics or the like and designed for use with air guns firing steel (non-lead) BB's or pellets, the pro¬ vision of the liquid lubricant spray and circulating system can, as previously pointed out, be dispensed with, since frictional drag is minimized by the self- lubricating nature of the materials of which the trap is made. Even so, however, the trap is preferably constructed with full seals at all junctures, achieved by forming the trap as a one-piece molding or by suit- ably bonding or fusing the various plates to one an¬ other with the aid of heat, adhesives or other bonding agents, which apart from serving to rigidify and strengthen the structure of the trap, also aids in preventing the escape of any BB's or pellets fired into the trap. Reverting now to the projectile B (whether it be a bullet or a BB) entering the trap, the residu¬ al energy of the same, after it has passed through the throat or exit opening 13d of the passageway structure, is dissipated as the projectile circumnavi- gates the deceleration chamber 15. The spent projec¬ tile ultimately falls off the terminal part 25c of the chamber wall 25 and over the end edge 25c" thereof onto the initial part 25a of the wall 25 contiguous to the lower plate 13b of the passageway structure 13. From there, the projectile rolls or slides through the throat 13d along the plate 13b, as indicated at B-4 and by the arrow Y in Fig. 1, toward the discharge region thereof. This movement occurs to a certain extent by dint of the force of gravity and, in the event a liquid lubricant has been sprayed against the initial part 25a of the chamber wall (so that the trap may properly be termed a "wet" trap) , is assisted by the liquid as it flows downwardly along the chamber wall and thence through the throat 13d and along the lower plate 13b of the passageway structure 13 toward the front of the trap. In the case of the "wet" trap, the liquid finally drops through the opening 32 into the trough 31 and thence into the collecting vessel 17. A transverse ridge or plate 35 is provided atop the end portion 13b' of the plate 13b at the downstream edge of the opening 32 to constitute a bar¬ rier for deflecting the liquid and the projectiles, and also any projectile fragments, shells and casings, descending along the plate 13b into the opening 32 and inhibiting their passage over the plate end portion 13b'. In the case of the "dry" trap, on the other hand, the BB or pellet may also be permitted to drop through the opening 32 in the lower plate 13b and into a collecting vessel positioned thereunder, but alter¬ natively the provision of the opening may be dispensed with and the BB or pellet simply brought to a halt by the barrier plate or ridge 35. The use of the white water lubricant in a "wet" trap, apart from its lubricating and flushing functions, also affords yet another advantage, in that it adds a measure of soundproofing to the trap. In fact, it has been found that the noise level of bul¬ lets traveling through the trap is as much as 10 db less in the presence of the liquid than in its absence, because the white water absorbs vibrations and harmonics resulting from the impacts of the bul¬ lets against and their movements along the plates 13a and 13b of the passageway structure and the circumfer¬ ential boundary wall 25 of the deceleration chamber 15. It will be apparent from what has been de¬ scribed so far, that the space requirements for the traps according to the invention are relatively mini¬ mal. Any such trap, furthermore, weighs less than 226.8 kg (500 lbs.), and in the case of a trap made of plastics, the weight will most likely be less than 90.7 kg (200 lbs.). The trap thus is able to be readily moved from one location to another, while nev¬ ertheless being fully stable when in use. It should also be noted that the particular "ramp angle" (the angle of inclination of the passageway plates 13a and 13b) selected for any given trap according to the in¬ vention will in general depend on the type of ammuni¬ tion, that is to say, the weight and velocity of the projectile, to be fired into it. Thus, a 15* angle is acceptable for BB's or pellets fired from air guns. but angles of 12* or less (down to about 7") would be more appropriate for powder-discharged bullets. Industrial Applicability The bullet trap according to the invention is usable by manufacturers of firearms and ammunition for catching bullets fired for test purposes, by mili¬ tary and police forces for catching bullets fired dur¬ ing the training of soldiers and law enforcement per¬ sonnel in the use of firearms, and by proprietors and operators of recreational firing ranges for catching bullets fired for purposes of practice, amusement and competition.

Claims: Claims 1. A bullet trap for catching and de- energizing a projectile fired along a substantially horizontal path of flight from a firearm such as a rifle, shotgun, handgun, airgun, or the like, which trap includes a first pair of spaced flat plates lo¬ cated on opposite sides of the path of flight of the projectile and a second pair of spaced flat plates arranged transverse to said first plates on opposite sides of the flight path of the projectile, with said plates defining the respective four sides of a pas¬ sageway having at its front end an entrance opening and at its rear end a throat through which the projec¬ tile can pass, and a spent projectile decelerating and energy-dissipating chamber the circumferential bound¬ ary wall of which is of generally spiral configuration and the opposite end walls of which are constituted by portions of said second plates, with said passageway communicating with said chamber substantially tangen- tially of the latter through said throat; character¬ ized in that: (a) said first plates (i) are located, respectively, above and below said path of flight of the projectile and (ii) are oriented at respective an- gles of inclination of between 0* and about 15* to the horizontal; (b) said decelerating and energy-dis¬ sipating chamber has a substantially horizontal axis between said opposite end walls, and said circumfer- ential boundary wall of said chamber is defined by a curved extension of the lower one of said first plates, (i) an initial part of said circumferential boundary wall extending from said throat generally rearwardly of said passageway first at an inclination to the horizontal substantially the same as that of said lower first plate and then arcuately upwardly relative thereto, (ii) a middle part of said circum¬ ferential boundary wall extending arcuately from said initial part generally frontwardly of said passageway first upwardly and then downwardly, and (iii) a termi- nal part of said circumferential boundary wall extend¬ ing arcuately from said middle part downwardly and generally rearwardly of said passageway into substan¬ tially coplanar relation with the upper one of said first plates and having an end edge overlying the re- gion of said initial part of said circumferential boundary wall contiguous to said lower first plate; and (c) the entire circumferential bound¬ ary wall of said chamber has no part the radius of curvature of which is less than about 15.25 cm; whereby a projectile fired into said pas¬ sageway through said entrance opening along a substan¬ tially horizontal path of flight and coming into con¬ tact with one of said first plates is deflected there- by through a small angle into a flight path running generally along the contacted first plate but out of contact therewith and ultimately passes through said throat of said passageway and impacts against said initial part of said circumferential boundary wall of said chamber at a relatively low angle so as not to be shattered thereby nor to damage the same, and the projectile then circumnavigates the chamber with grad¬ ually decreasing speed while in contact with said circumferential boundary wall until the energy of the projectile has been substantially dissipated, so that the spent projectile ultimately falls from said termi¬ nal part of said circumferential boundary wall over said end edge thereof onto said initial part of said circumferential boundary wall just rearwardly of said throat of said passageway and moves through said throat back into said passageway and along said lower first plate for removal from the trap. 2. A bullet trap as claimed in claim 1; further characterized in that a collecting vessel is located under a discharge region of said lower first plate for receiving spent projectiles, fragments thereof, shells, jackets and casings moving along said lower first plate from said chamber. 3. A bullet trap as claimed in claim 2; further characterized in that spray nozzle means are provided within said chamber for spraying a liquid lubricant against said circumferential boundary wall of said chamber, for reducing frictional contact be¬ tween said circumferential boundary wall and a projec¬ tile traveling along the latter and for flushing spent projectiles, projectile fragments, shells, jackets, casings, and lead dust, if any, out of said chamber and along said lower first plate into said collecting vessel. 4. A bullet trap as claimed in claim 3; wherein said liquid lubricant is a white water lubri¬ cant. 5. A bullet trap as claimed in claim 3 or 4; wherein said spray nozzle means comprises a conduit for said liquid lubricant, said conduit extending substantially parallel to the axis of said chamber and having a plurality of orifices therein arranged so as to direct said liquid lubricant from said conduit against said initial part of said circumferential boundary wall of said chamber. 6. A bullet trap as claimed in any one of claims 3, 4 and 5; wherein said collecting vessel in an upper region thereof includes a substantially hori¬ zontal strainer member extending across the entire expanse of said collecting vessel, said strainer mem- ber having openings therein which are sufficiently small to permit only lead dust, if any is entrained in said liquid lubricant flowing through said passageway, to pass through said strainer member to the bottom of said collecting vessel and to prevent passage of larg¬ er objects such as spent projectiles, fragments there- of, shells, -jackets, and casings. 7. A bullet trap as claimed in any one of claims 3, 4, 5 and 6; further characterized in that pipe means are provided for establishing communication between said collecting vessel and said spray nozzle means, and that pump means are operatively connected with said pipe means for recirculating said liquid lubricant from said collecting vessel to said spray nozzle means. 8. A bullet trap as claimed in claim 7; wherein said pipe means is connected to said collect¬ ing vessel in an upper region thereof where said liq¬ uid lubricant is clear of any solids. 9. A bullet trap as claimed in any one of claims 1 to 8; wherein, if the trap is intended for catching a powder-discharged bullet fired from a fire¬ arm not more powerful than a .22 long rifle, said first and second plates and said circumferential boundary wall of said chamber are made of high tensile steel sheet, the angle of inclination of at least one of said first plates to the horizontal is about 12*, and the radii of curvature of the various parts of said circumferential boundary wall of said chamber are on the order of not less than about 20.3 cm. 10. A bullet trap as claimed in claim 9; wherein the angle of inclination of said lower first plate to the horizontal is about 12 * . 11. A bullet trap as claimed in claim 9; wherein the angle of inclination of each of said first plates to the horizontal is about 12*. 12. A bullet trap as claimed in any one of claims 1 to 8; wherein, if the trap is intended for catching a powder-discharged bullet fired from a fire¬ arm not more powerful than a .44 Magnum handgun, said first and second plates and said circumferential boundary wall of said chamber are made of high tensile steel sheet, the angle of inclination of at least one of said first plates to the horizontal is about 7*, and the radii of curvature of the various parts of said circumferential boundary wall of said chamber are on the order of not less than about 22.9 cm. 13. A bullet trap as claimed in claim 12; wherein the angle of inclination of said lower first plate to the horizontal is about 7*. 14. A bullet trap as claimed in claim 12; wherein the angle of inclination of each of said first plates to the horizontal is about 7* . 15. A bullet trap as claimed in any one of claims 1 to 8; wherein, if the trap is intended for catching a powder-discharged bullet fired from a fire¬ arm more powerful than a .44 Magnum handgun, said first and second plates and said circumferential boundary wall of said chamber are made of high tensile steel sheet, the angle of inclination of at least one of said first plates to the horizontal is not greater than about 7*, and the radii of curvature of the vari- ous parts of said circumferential boundary wall of said chamber are on the order of not less than about 71.1 cm. 16. A bullet trap as claimed in claim 15; wherein the angle of inclination of said lower first plate to the horizontal is not greater than about 7". 17. A bullet trap as claimed in claim 15; wherein the angle of inclination of each of said first plates to the horizontal is not greater than about 7* . 18. A bullet trap as claimed in claim 1 or 2; wherein, if the trap is intended for catching a BB or pellet fired from an air gun, said first and second plates and said circumferential boundary wall of said chamber are made of self-lubricating plastics or graphite, the angle of inclination of at least one of said first plates to the horizontal is about 15*, and 5 the radii of curvature of the various parts of said circumferential boundary wall of said chamber are on the order of not less than about 15.2 cm. 19. A bullet trap as claimed in claim 18; wherein the angle of inclination of said lower first ° plate to the horizontal is about 15* . 20. A bullet trap as claimed in claim 18; wherein the angle of inclination of each of said first plates to the horizontal is about 15*. 21. A bullet trap as claimed in any one of claims 1 to 20; further characterized in that an elon¬ gated band is arranged to have a portion thereof ex¬ tending across said entrance opening of said passage¬ way, means are provided for moving said band longitu¬ dinally thereof past said entrance opening for selec- tively juxtaposing successive different portions of the band to said entrance opening, and a plurality of target regions are provided on said band so that by appropriate movement of the latter a desired one of said target regions on said portion of said band can e positioned in front of said passageway to facili¬ tate aiming of a firearm toward said entrance opening. 22. A bullet trap for catching and deener- gizing a powder-discharged bullet fired along a sub¬ stantially horizontal path of flight from a firearm such as a rifle, shotgun, handgun, or the like, which trap includes a first pair of spaced flat plates lo¬ cated on opposite sides of the path of flight of the bullet and a second pair of spaced flat plates ar¬ ranged transverse to said first plates on opposite sides of the flight path of the bullet, with said plates defining the respective four sides of a pas- sageway having at its front end an entrance opening and at its rear end a throat through which the bullet can pass, and a spent bullet decelerating and energy- dissipating chamber the circumferential boundary wall of which is of generally spiral configuration and the opposite end walls of which are constituted by por¬ tions of said second plates, with said passageway communicating with said chamber substantially tangen¬ tially of the latter through said throat; character- ized in that: spray nozzle means are provided within said chamber for spraying against said circumferential boundary wall of the latter a liquid lubricant for reducing frictional contact between said circumferen- tial boundary wall and any bullets traveling along the same, and the quantity of said liquid lubricant sprayed into said chamber is sufficient to engulf and flush away any lead dust generated by the travel of said bullets along said circumferential boundary wall as well as spent bullets, fragments thereof, shells, jackets and casings. 23. A bullet trap as claimed in claim 22; wherein said liquid lubricant is a white water lubri¬ cant. 24. A bullet trap as claimed in claim 22 or 23; further characterized in that a collecting vessel is located under a discharge region of said lower first plate for receiving said liquid lubricant flow¬ ing along said lower first plate and any lead dust and any spent bullets, fragments thereof, shells, jackets and casings engulfed by and moving with said liquid lubricant. 25. A bullet trap as claimed in claim 24; further characterized in that pipe means are provided and connected to said collecting vessel and said spray nozzle means to establish communication between said collecting vessel and said spray nozzle means, and that pump means are operatively connected with said pipe means for recirculating said liquid lubricant from said collecting vessel to said spray nozzle 5 means. 26. A bullet trap as claimed in claim 25; wherein said spray nozzle means comprise a conduit for said liquid lubricant, said conduit extending substan¬ tially parallel to the axis of said chamber and being ° connected to said pipe means, and said conduit having a plurality of orifices therein arranged so as to direct said liquid lubricant from said conduit against said circumferential boundary wall of said chamber. 27. A bullet trap as claimed in any one of claims 25 and 26; wherein said pipe means are connect¬ ed to said collecting vessel in an upper region there¬ of where said liquid lubricant is clear of any solids. 28. A bullet trap as claimed in any one of claims 25 to 27; further characterized in that said collecting vessel in an upper region thereof above the connecting location of said pipe means includes a substantially horizontal strainer member extending across the entire expanse of said collecting vessel, said strainer member having openings therein which are sufficiently small to permit only lead dust, if any is entrained in said liquid lubricant flowing through said passageway, to pass through said strainer member to the bottom of said collecting vessel and to prevent passage of larger objects such as spent bullets, frag- ments thereof, shells, jackets, and casings. 29. A bullet trap as claimed in claim 22; wherein said spray nozzle means comprise a conduit for said liquid lubricant, said conduit extending substan- tiallyparaliel to the axis of said chamber and having a plurality of orifices therein arranged so as to direct said liquid lubricant from said conduit against said circumferential boundary wall of said chamber. AMENDED CLAIMS [received by the International Bureau on 25 March 1992(25.03.92); original claims 1,9-29 amended; new claims 30-36 added; other claims unchanged (9 pages)] 1. A bullet trap for catching and de- energizing projectiles fired along a substantially horizontal path of flight into the trap from manual firearms not more powerful than a .44 Magnum handgun, which trap includes a first pair of spaced flat plates located on opposite sides of said path of flight and a second pair of spaced flat plates arranged transverse to said first plates on opposite sides of said path of flight, with said plates defining the respective four sides of a passageway having at its front end an en¬ trance opening and at its rear end a throat through which the projectiles can pass, and a spent projectile decelerating and energy-dissipating chamber the circumferential boundary wall of which is of generally spiral configuration and the opposite end walls of which are constituted by portions of said second plates, with said passageway communicating with said chamber substantially tangentially of the latter through said throat; characterized in that: (a) said first plates (i) are located, respectively, above and below said path of flight and (ii) are oriented at respective angles of inclination of between 0° and about 15° to the horizontal; and (b) said decelerating and energy-dis¬ sipating chamber has a substantially horizontal axis between said opposite end walls, and said circumfer¬ ential boundary wall of said chamber is defined by a curved extension of the lower one of said first plates, (i) an initial part of said circumferential boundary wall extending from said throat generally rearwardly of said passageway first at an inclination to the horizontal substantially the same as that of said lower first plate and then arcuately upwardly relative thereto, (ii) a middle part of said circum¬ ferential boundary wall extending arcuately from said initial part generally frontwardly of said passageway first upwardly and then downwardly, and (iii) a termi- nal part of said circumferential boundary wall extend¬ ing arcuately from said middle part downwardly and generally rearwardly of said passageway into substan¬ tially coplanar relation with the upper one of said first plates and having an end edge overlying the re- gion of said initial part of said circumferential boundary wall contiguous to said lower first plate; whereby a projectile fired into said pas¬ sageway through said entrance opening along said path of flight and coming into contact with one of said first plates is deflected thereby through a small angle into a flight path running generally along the contacted first plate but out of contact therewith and ultimately passes through said throat of said passage¬ way and impacts against said initial part of said circumferential boundary wall of said chamber at a relatively low angle so as not to be shattered thereby nor to damage the same, and the projectile then cir¬ cumnavigates the chamber with gradually decreasing speed while in contact with said circumferential boundary wall until the energy of the projectile has been substantially dissipated, so that the spent pro¬ jectile ultimately falls from said terminal part of said circumferential boundary wall over said end edge thereof onto said initial part of said circumferential boundary wall just rearwardly of said throat of said passageway and moves through said throat back into said passageway and along said lower first plate for removal from the trap. 2. A bullet trap as claimed in claim 1; further characterized in that a collecting vessel is located under a discharge region of said lower first plate for receiving spent projectiles, fragments thereof, shells, jackets and casings moving along said lower first plate from said chamber. 3. A bullet trap as claimed in claim 2; further characterized in that spray nozzle means are provided within said chamber for spraying a liquid lubricant against said circumferential boundary wall of said chamber, for reducing frictional contact be¬ tween said circumferential boundary wall and a projec- tile traveling along the latter and for flushing spent projectiles, projectile fragments, shells, jackets, casings, and lead dust, if any, out of said chamber and along said lower first plate into said collecting vessel. 4. A bullet trap as claimed in claim 3; wherein said liquid lubricant is a white water lubri¬ cant. 5. A bullet trap as claimed in claim 3 or 4; wherein said spray nozzle means comprises a conduit for said liquid lubricant, said conduit extending substantially parallel to the axis of said chamber and having a plurality of orifices therein arranged so as to direct said liquid lubricant from said conduit against said initial part of said circumferential boundary wall of said chamber. 6. A bullet trap as claimed in any one of claims 3, 4 and 5; wherein said collecting vessel in an upper region thereof includes a substantially hori¬ zontal strainer member extending across the entire expanse of said collecting vessel, said strainer mem¬ ber having openings therein which are sufficiently small to permit only lead dust, if any is entrained in said liquid lubricant flowing through said passageway, to pass through said strainer member to the bottom of said collecting vessel and to prevent passage of larg¬ er objects such as spent projectiles, fragments there- of, shells, jackets, and casings. 7. A bullet trap as claimed in any one of claims 3, 4, 5 and 6; further characterized in that pipe means are provided for establishing communication between said collecting vessel and said spray nozzle means, and that pump means are operatively connected with said pipe means for recirculating said liquid lubricant from said collecting vessel to said spray nozzle means. 8. A bullet trap as claimed in claim 7; wherein said pipe means is connected to said collect¬ ing vessel in an upper region thereof where said liq¬ uid lubricant is clear of any solids. 9. A bullet trap as claimed in any one of claims 1 to 8; wherein, for catching a projectile in the form of a powder-discharged bullet fired from a firearm not more powerful than a .22 long rifle, said first and second plates and said circumferential boundary wall of said chamber are made of high tensile steel sheet, and the angle of inclination of at least one of said first plates to the horizontal is about 12° . 10. A bullet trap as claimed in claim 9; wherein the angle of inclination of said lower first plate to the horizontal is about 12°, the inclination of said lower first plate being upward in the direc¬ tion from said entrance opening to said throat. 11. A bullet trap as claimed in claim 9; wherein the angles of inclination of said first plates to the horizontal are about 12° in opposite senses, with said first plates converging toward each other in the direction from said entrance opening to said throat. 12. A bullet trap as claimed in any one of claims 1 to 8; wherein, for catching projectile in the form of a powder-discharged bullet fired from a fire- arm not more powerful than a .44 Magnum handgun, said first and second plates and said circumferential boundary wall of said chamber are made of high tensile steel sheet, and the angle of inclination of at least one of said first plates to the horizontal is about 7°. 13. A bullet trap as claimed in claim 12; wherein the angle of inclination of said lower first plate to the horizontal is about 7°, the inclination of said lower first plate being upward in the direc¬ tion from said entrance opening to said throat. 14. A bullet trap as claimed in claim 12; wherein the angles of inclination of said first plates to the horizontal are about 7° in opposite senses, with said first plates converging toward each other in the direction from said entrance opening to said throat. 15. A bullet trap as claimed in any one of claims l to 8; wherein, for catching a projectile in the form of a powder-discharged bullet fired from a firearm more powerful than a .44 Magnum handgun, said first and second plates and said circumferential boundary wall of said chamber are made of high tensile steel sheet, and the angle of inclination of at least one of said first plates to the horizontal is not greater than about 7* . 16. A bullet trap as claimed in claim 15; wherein the angle of inclination of said lower first plate to the horizontal is not greater than about 7° , the inclination of said lower first plate being upward in the direction from said entrance opening to said throat. 17. A bullet trap as claimed in claim 15; wherein the angles of inclination of said first plates to the horizontal are not greater than about 7° in opposite senses, with said first plates converging A y toward each other in the direction from said entrance opening to said throat. 18. A bullet trap as claimed in claim 1 or 2; wherein, for catching a projectile in the form of a BB or pellet fired from an air gun, the angle of in¬ clination of at least one of said first plates to the horizontal is about 15°. 19. A bullet trap as claimed in claim 18; wherein the angle of inclination of said lower first plate to the horizontal is about 15°, the inclination of said lower first plate being upward in the direc¬ tion from said entrance opening to said throat. 20. A bullet trap as claimed in claim 18; wherein the angles of inclination of said first plates to the horizontal are about 15° in opposite senses, with said first plates converging toward each other in the direction from said entrance opening to said throat. 21. A bullet trap as claimed in any one of claims 1 to 8; wherein said circumferential boundary wall of said chamber at no part thereof has a radius of curvature which is less than about 15.2 cm. 22. A bullet trap as claimed in any one of claims 9, 10 and 11; wherein said circumferential boundary wall of said chamber at no part thereof has a radius of curvature which is less than about 20.3 cm. 23. A bullet trap as claimed in any one of claims 12, 13 and 14; wherein said circumferential boundary wall of said chamber at no part thereof has a radius of curvature which is less than about 22.9 cm. 24. A bullet trap as claimed in any one of claims 15, 16 and 17; wherein said circumferential boundary wall of said chamber at no part thereof has a radius of curvature which is less than about 71.1 cm. 25. A bullet trap as claimed in any one of claims 18, 19 and 20; wherein said circumferential boundary wall of said chamber at no part thereof has a radius of curvature which is less than about 15.2 cm. 26. A bullet trap as claimed in any one of claims 18, 19, 20 and 25; wherein said first and sec- ond plates and said circumferential boundary wall of said chamber are made of plastics or graphite. 27. A bullet trap as claimed in any one of claims 1 to 26; further characterized in that an elon¬ gated band is arranged to have a portion thereof ex- tending across said entrance opening of said passage¬ way, means are provided for moving said band longitu¬ dinally thereof past said entrance opening for selec¬ tively juxtaposing successive different portions of the band to said entrance opening, and a plurality of target regions are provided on said band so that by appropriate movement of the latter a desired one of said target regions on said portion of said band can be positioned in front of said passageway to facili¬ tate aiming of a firearm toward said entrance opening. 28. A bullet trap for catching and deener- gizing a powder-discharged bullet fired along a sub¬ stantially horizontal path of flight from a firearm such as a rifle, shotgun, handgun, or the like, which trap includes a first pair of spaced flat plates lo- cated on opposite sides of the path of flight of the bullet and a second pair of spaced flat plates ar¬ ranged transverse to said first plates on opposite sides of the flight path of the bullet, with said plates defining the respective four sides of a pas- sageway having at its front end an entrance opening and at its rear end a throat through which the bullet can pass, and a spent bullet decelerating and energy- dissipating chamber the circumferential boundary wall of which is of generally spiral configuration and the opposite end walls of which are constituted by por- tions of said second plates, with said passageway communicating with said chamber substantially tangen¬ tially of the latter through said throat; character¬ ized in that: spray nozzle means are provided within said chamber for spraying against said circumferential boundary wall of the latter a liquid lubricant for reducing frictional contact between said circumferen¬ tial boundary wall and any bullets traveling along the same, and the quantity of said liquid lubricant sprayed into said chamber is sufficient to engulf and flush away any lead dust generated by the travel of said bullets along said circumferential boundary wall as well as spent bullets, fragments thereof, shells, jackets and casings. 29. A bullet trap as claimed in claim 28; wherein said liquid lubricant is a white water lubri¬ cant. 30. A bullet trap as claimed in any one of claims 28 and 29; further characterized in that a col¬ lecting vessel is located under a discharge region of said lower first plate for receiving said liquid lu¬ bricant flowing along said lower first plate and any lead dust and any spent bullets, fragments thereof, shells, jackets and casings engulfed by and moving with said liquid lubricant. 31. A bullet trap as claimed in claim 30; further characterized in that pipe means are provided and connected to said collecting vessel and said spray nozzle means to establish communication between said collecting vessel and said spray nozzle means, and that pump means are operatively connected with said pipe means for recirculating said liquid lubricant from said collecting vessel to said spray nozzle means. 32. A bullet trap as claimed in claim 31; wherein said spray nozzle means comprise a conduit for said liquid lubricant, said conduit extending substan¬ tially parallel to the axis of said chamber and being connected to said pipe means, and said conduit having a plurality of orifices therein arranged so as to direct said liquid lubricant from said conduit against said circumferential boundary wall of said chamber. 33. A bullet trap as claimed in any one of claims 31 and 32; wherein said pipe means are connect- ed to said collecting vessel in an upper region there¬ of where said liquid lubricant is clear of any solids. 34. A bullet trap as claimed in any one of claims 31, 32 and 33; further characterized in that said collecting vessel in an upper region thereof above the connecting location of said pipe means in¬ cludes a substantially horizontal strainer member extending across the entire expanse of said collecting vessel, said strainer member having openings therein which are sufficiently small to permit only lead dust, if any is entrained in said liquid lubricant flowing through said passageway, to pass through said strainer member to the bottom of said collecting vessel and to prevent passage of larger objects such as spent bul¬ lets, fragments thereof, shells, jackets, and casings. 35. A bullet trap as claimed in claim 28; wherein said spray nozzle means comprise a conduit for said liquid lubricant, said conduit extending substan- tiallyparallel to the axis of said chamber and having a plurality of orifices therein arranged so as to direct said liquid lubricant from said conduit against said circumferential boundary wall of said chamber. 36. A bullet trap substantially as herein described with reference to any one of the illustrated embodiments. STATEMENT UNDER ARTICLE19 The amendments made in the claims, apart from certain stylistic and essentially editorial changes, are based on the applicant's view that the dimensional limita¬ tions set forth in paragraph (c) of the "characterizing" section of original claim 1 and in each of original claims 9, 12, 15 and 18, namely, the radii of curvature of the various parts of the deceleration chamber, are actually not primary features of the invention and consequently ought to be excised from these claims and rather presented in respec¬ tive suitable dependent claims. By the same token, the inventor is also of the view that the "materials" limitation (plastics or graphite) set forth in original claim 18 is likewise not of primary significance and should therefore be excised from that claim and rather presented in a respective new dependent claim. The relationship of the new claims to the original claims is as follows: New claim 1 is essentially the same as original claim 1 but with the latter amended, on the one hand, to replace the possibly indefinite clause reading "a projectile fired . . . from a firearm such as . . . or the like" found in the preamble of the claim (page 35, lines 3-5) by a clause reading —projectiles fired . . . into the trap from manual firearms not more powerful than a .44 Magnum handgun—, and also amended, on the other hand, to cancel original paragraph (c) found in the "characterizing" section of the claim (page 36, lines 13-15) so as to eliminate from the claim all references to the radii of curvature of the circumferential boundary wall of the deceleration chamber. New claims 2-8 correspond to original claims 2-8, respectively, without change. New claims 9-11 are multiple dependent on claims 1-8 and correspond to original claims 9-11, respectively, with claim 9 amended to eliminate the reference to the radii of curvature of the chamber wall (page 38, lines 26-28), and with claims 10 and 11 amended to specifically define the direction of the 12° inclination of the first plates of the passagewa . New claims 12-14 are multiple dependent on claims 1-8 and correspond to original claims 12-14, respectively, with claim 12 amended to eliminate the reference to the radii of curvature of the chamber wall (page 39, lines 7-9), and with claims 13 and 14 amended to specifically define the direction of the 7° inclination of the first plates of the passagewa . New claims 15-17 are multiple dependent on claims 1-8 and correspond to original claims 15-17, respectively, 5 o with claim 15 amended to eliminate the reference to the radii of curvature of the chamber wall (page 39, lines 24- 27) , and with claims 16 and 17 amended to specifically define the direction of the 7" inclination of the first plates of the passageway. New claims 18-20 are multiple dependent on claims 1-8 and correspond to original claims 18-20, respectively, with claim 18 amended to eliminate the reference to the material of which the trap is made (page 40, lines 2-3) and the reference to the radii of curvature of the chamber wall (page 40, lines 5-7) , and with claims 19 and 20 amended to specifically define the direction of the 15° inclination of the first plates of the passageway. New claims 21-25 are dependent, inter alia, on new claims 1, 9, 12, 15 and 18, respectively, and reintroduce the references to the various radii of curvature values previously excised from the corresponding original claims. New claim 26 is multiple dependent, inter alia, on new claims 18 and 25 and reintroduces the reference to the material previously excised from claim 18. New claim 27 corresponds to original claim 21 without change other than being made multiple dependent on new claims 1-26. New claim 28 corresponds to original claim 22 without change. New claims 29-35 correspond, respectively, to original claims 23-29 without change other than being made dependent either on new claim 28 or on others of the new claims 29-33, as the case may be. New claim 36 is an omnibus claim.

Inventors: COBURN RONALD, COBURN, RONALD
Applicants: COBURN RONALD, COBURN, RONALD
Application year: 1991
Main classification: F41J1
IPC codes: F41J13