Pyrotechnic Target and Method of Manufacture

Abstract

An impact initiated pyrotechnic target is shown in the form of a thin metal disc. The disc is manufactured using a shell casing in the form of a metal disk having a flat, round exposed disc surface and a circumscribing cylindrical lip. The lip extends upwardly past the exposed disc surface and is turned in on a radius. The exposed surface of the disk inside the periphery of the cylindrical lip is coated with a pyrotechnic composition coating layer which can be initiated by the impact of an inert projectile. A cardboard lid is snapped into place over the exposed disc surface and is held in place by the turned-in periphery of the cylindrical lip of the disc.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to impact initiated pyrotechnic targets and to a method for manufacturing the same.

2. Description of the Prior Art

The prior art shows many examples of practice targets for use in the various shooting arts. For example, the targets described in the prior art may be used in conjunction with firearms such as shotguns, rifles and pistols, and air propelled arms such as air rifles and air pistols. They may also be used with a bow and arrow target. The target may be of the type which is intended to be held in a fixed position, and which may have indicia located thereon such as a number of concentric rings defining a “bullseye”. The target might also assume various other shapes, including iron silhouettes, and the like. Alternatively, the target may be intended to be used as a moving target such as a “clay pigeon”used at trap and skeet ranges.

One disadvantage of the prior art targets was the fact that it could sometimes be difficult to detect whether the target had, in fact, been hit. For example, the typical clay pigeon used at trap and skeet ranges comprises a clay disc which shatters when hit by shot from a shotgun. However, it is sometimes difficult to discern whether the clay disc has been shot as the shattering is not particularly dramatic. Similarly when shooting stationary targets or targets on moving vehicles the indication that the target has been shot is not usually dramatic.

To address concerns of this type, U.S. Pat. No. 727,419, as early as May 5, 1903, shows a flying disk target which is coated with a fulminate type explosive or detonating substance. It is also known from U.S. Pat. No. 4,498,677 and WO02/35175 to provide an explosive target which registers a hit by providing an explosive event. The clay pigeon described in WO/0235175 is made from a disc shaped rigid plastic housing. The housing contains impact sensitive primers such as a mixture of red phosphorus and sodium chlorate as used in caps for cap guns, coated on a fibrous disc, and a pyrotechnic such as magnesium flash powder. The pyrotechnic can be made into a paste and pressed into the housing. One face of the disc shaped housing has an opening spanning most of its area. The opening is closed by a cardboard disc which is readily penetrated by shot.

The clay pigeon is fired from a trap so that the face of the housing closed by the cardboard disc faces generally downward. Thus when hit, shot pierces the cardboard disc, travels through the pyrotechnic and impacts on the primer, so that the primer ignites and thereby ignites the pyrotechnic which explodes. The explosion of the pyrotechnic can produce a visible flash, a more prolonged burning, an audible noise or a combination of any of these.

However, despite advances of this kind that have been made in the field of pyrotechnic targets, it has proven difficult to produce a pyrotechnic which can be satisfactorily ignited by the impact of a relatively low energy projectile such as a pellet or slug discharged by a pneumatic weapon such as an air rifle. Additionally, while there is a need to provide a target which is sufficiently sensitive to provide a reaction to a hit by a relatively low energy projectile such as an air gun pellet, the active pyrotechnic used in the target should not be so sensitive as to present a hazard during manufacture, handling or storage. A related and important consideration is that the nature of the active pyrotechnic should not render its preparation illegal under national laws.

It is accordingly an object of the invention to overcome one or more of the disadvantages mentioned above with respect to the art of pyrotechnic target devices.

SUMMARY OF THE INVENTION

According to the method of the present invention, there is provided an impact initiated pyrotechnic target containing an impact initiated pyrotechnic composition which can be initiated by the impact of an inert projectile. In the first step of the method of the invention, there is provided a thin metal disc, the disc having a flat, round exposed disc surface and a peripherally circumscribing cylindrical lip. The lip extends upwardly past the exposed disc surface a predetermined height. The disc lip is also turned-over and turned-in upon itself on a given radius. The exposed surface of the disk inside the periphery of the cylindrical lip has applied thereto a pyrotechnic composition coating layer which can be initiated by the impact of an inert projectile. A circular protective lid is snapped into place over the exposed disc surface and the pyrotechnic composition and is held in place by the turned-over and turned-in periphery of the cylindrical lip of the disc to thereby form a completed shell casing.

Preferably, the pyrotechnic composition which is used as the coating layer is made up of pyrotechnic agents in a binder composition, the binder composition being initially flowed by gravity over the exposed disc surface and then dried.

The cardboard lid which is used to cover the pyrotechnic layer can be laminated with a suitable plastic so that it is water repellant.

The thin metal disc used in making the completed shell casings can also be provided with an adhesive patch which is applied to the rear surface of the disc to allow the disc to be temporarily stuck to a target background surface. Alternatively, the metal disc can be formed of a magnetically attractive metal with the target disc being held within an accompanying disc receiving holder. The disc receiving holder can be provided with a magnetic region for attracting and retaining the metal target disc within the holder. The preferred disc receiving holder is a cylindrically shaped body having a disc receiving recess for receiving the target disc, the holder being sufficiently stiff to support the target disc upon impact form an inert projectile and also being re-usable.

Additional objects, features and advantages will be apparent in the description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side, cross sectional view of the shell casing used in the method of the present invention.

FIG. 2 is a similar side, cross sectional view of the shell casing, showing the turned-over and turned-in edge of the lip which is used to contain a cardboard lid in a later step in the manufacturing process.

FIG. 3 shows the application of a layer of pyrotechnic composition to the upper exposed surface of the disc region of the shell casing, the pyrotechnic composition being shown in somewhat exaggerated fashion for ease of illustration.

FIG. 4 a is a view similar to FIG. 3, but showing the installation of the cardboard lid over the upper exposed surface of the shell casing and over the pyrotechnic composition.

FIG. 4 b is a view similar to FIG. 3, but showing the turned-over and turned-in edges of the lip of the shell casing in somewhat exaggerated fashion for ease of illustration and also showing an adhesive backing applied to the rear face of the casing.

FIGS. 5 and 6 show a completed shell casing with an associated casing holder, the center of the shell holder having a magnet for retaining the shell casing by magnetic attraction.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processes and manufacturing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the invention herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the claimed invention.

The method of manufacturing the impact initiated pyrotechnic target of the invention will now be described in greater detail. The manufacturing process begins with the empty shell casing 11 shown in FIG. 1 of the drawings. The shell casing 11 is a thin metal disc typically formed of a ferrous metal such as steel. As can be seen in FIG. 1, the disc 11 has a flat, round exposed disc surface 13 and a peripherally circumscribing cylindrical lip 15. The lip 15 extends upwardly past the exposed disc surface 13 a predetermined height so as to form a cavity for enclosing the pyrotechnic composition.

It will also be appreciated from FIG. 1 that the circumscribing lip 15 has an upper edge 17 which is turned-over and turned-in upon itself on a given radius (shown in FIG. 2 of the drawings). The turned-ver and turned-in edge is shown in exaggerated fashion in FIG. 4b. The flat, round exposed disc surface 13 has a given diameter which ranges from about 35 mm to about 70 mm. The cylindrical turned-over and turned-in lip has a vertical height, as measured from the exposed disc surface in the range from about 3 mm to about 8 mm. Preferably, the cylindrical turned-over and turned-in lip 15 has a vertical height of approximately 6.66 mm where the exposed disc surface 13 is approximately 62.90 mm, and a height of approximately 6.60 mm where the surface 13 is approximately 62.60 mm. The thickness of the disk body, as at the flat surface 13 is in the range from about 1 to 3 mm. However, it will be understood that targets of the invention may be smaller or larger than these dimensions, and that different charges will be used in accordance with the precise nature of the composition and intended application.

The exposed surface 13 of the disk inside the periphery of the cylindrical lip 15 has a pyrotechnic composition applied thereto. Preferably, the exposed disc surface 13 is coated with a pyrotechnic composition coating layer 19 (shown in FIG. 3) which can be initiated by the impact of an inert projectile. By “insert projectile” is meant a projectile which ignites the target by virtue of its kinetic energy on impact, i.e., a projectile which is non-explosive and does not react chemically with the pyrotechnic composition. The pyrotechnic composition layer 19 is also shown as being of exaggerated size, for ease of illustration. As will be explained, the layer will typically be only on the order of 1 to 4 mm in its final form.

The exact nature of the pyrotechnic composition layer 19 can vary according to the end application and various explosive type coatings are known in the relevant arts. With reference, for example, to U.S. Patent Publication No. 2010/0275802, of Green et al, the disclosure of which is incorporated herein by reference, there is shown a pyrotechnic composition which includes an oxidizing agent, a fuel or reducing agent, a sensitizer and an optional binder. In one example, the explosive powder contains an impact initiated pyrotechnic composition which comprises 32% charcoal, 48% potassium chlorate, 4% acaroid resin, and 16% thiourea with all percentages being by weight. In a preferred embodiment, this composition acts as an “ignition composition”, and is used in conjunction with a secondary, “signal” composition which enhances the visual effect of a strike on the target by a projectile. Another published reference, U.S. Pat. No. 4,498,677, to Dapkus, describes an explosive composition made up of potassium chlorate, sulphur, powdered aluminum and bran which is initiated by impact with an inert projectile. These pyrotechnic compositions are given by way of example only and should not be construed as limitations of the manufacturing method of the invention.

In the preferred case, a suitable explosive composition in dry powder form is mixed with a suitable binder with the liquid binder being dispersed onto the upper exposed surface 13 of the shell casing and allowed to spread by gravity to cover the exposed surface. The liquid composition is then baked until dried or allowed to air dry.

As can be appreciated from FIGS. 3 and 4a-4b, a protective lid 21 is then installed on top of the pyrotechnic composition. For example, the lid 21 can conveniently be formed from a suitable material, such as paper, card, or even aluminum foil. Cardboard and paper are preferred materials. A cardboard lid is readily penetrable by an inert projectile. By this is meant that shot or an arrow will easily pass through the lid while carrying enough momentum to set off the impact sensitive pyrotechnic composition upon impact. The use of some form of cardboard or paper has the advantage that paper is readily combustible and will burn easily with little remaining residue. In one form, the cardboard stock is laminated with a suitable plastic in order to render the ultimate assembly more waterproof.

The lid 21 is positioned over the pyrotechnic cover layer 19 by way of sealing against the upstanding wall region of the circumscribing lip 15 of the shell casing. More particularly, the circular cardboard lid 21 is snapped into place over the exposed disc surface and pyrotechnic composition and is held in place by the turned over and turned-in peripheral edge 17 of the cylindrical lip 15 of the disc to thereby form a completed shell casing. The retention of the cardboard lid 21 by the turned-over and turned-in peripheral edge 17 is shown in greater detail in FIG. 4b of the drawings. The process can be automated, for example, by placing a plurality of shell casings onto a revolving nest or carousel where a suitable loading tool comes down to snap the lids into place.

The completed shell casings can be used in a number of different target presentations, including mounting the casing on a traditional clay pigeon. As illustrated in FIG. 4a, the casing rear surface 23 can be provided with an adhesive patch 25 to allow the disc to be temporarily stuck to a target background surface.

In one preferred form, the casings of the invention are formed of a magnetically attractable metal. The metal casings 11 can then be mounted within an associated disc receiving holder, such as the holder 27 shown in FIG. 6. The holder 27 is a cylindrically shaped member with the target shell casing being mounted within a disc receiving recess 29. The preferred disc receiving holders are provided with a magnetic region, such as that provided by the permanent magnet 31, whereby the shell casing is held within the accompanying disc receiving holder. Without wishing to be bound by any particular theory, it is believed that it is the compression of the pyrotechnic composition which occurs upon impact which causes an increase in temperature which in turn causes the pyrotechnic composition to ignite. Depending on the impact initiating pyrotechnic composition and the end application, it may be necessary, or advantageous, to have a sort or “backing plate” in order to initiate ignition. The disk receiving holder 27 acts as a backing plate in the instant application. It has been found that due to the thin nature of the shell casing and of the layer of pyrotechnic coating composition, that the backing offered by the disc receiving holder aids in the impact and corresponding ignition process.

If desired, the disc receiving holder can be provided with an adhesive backing. Alternatively, a mounting hole 33 allows the holder to be mounted to a tree or other backstop.

An invention has been provided with several advantages. The targets of the invention may be used as targets for firearms, air-operated arms such as air rifles and air pistols, or even in archery. The targets may be intended for use as essentially a static target, in which instance the targets may consist essentially of the shell casings and disc receiving holders described above. Alternatively, the targets may be a moving target such as where the discs are mounted on a clay pigeon type target such as that described in the previously referenced WO 02/35175 publication. The manufacturing process provides a target disc which is lightweight and compact, making it easy to transport. The manufacturing process eliminates many of the disadvantages associated with the prior art by providing a pyrotechnic target disc which can be satisfactorily ignited by the impact of a relatively low energy projectile such as a pellet or slug discharged by a pneumatic weapon such as an air rifle. While the target discs of the invention are sufficiently sensitive to provide a reaction to a hit by a relatively low energy projectile such as an air gun pellet, they are not so sensitive as to present a hazard during manufacture, handling or storage. The resulting target discs and associated pyrotechnic compositions comply with all the applicable national laws respecting fireworks and explosives.

While the invention has been shown in only one of its forms, it is not thus limited, but is susceptible to various modifications without departing from the spirit thereof.

Claims

1. A method of manufacturing an impact initiated pyrotechnic target in the form of a shell casing made from a thin metal disc, the method comprising the steps of: providing a thin metal disc, the disc having a flat, round exposed disc surface and a peripherally circumscribing cylindrical lip, the lip extending upwardly past the exposed disc surface a predetermined height;the disc lip also being turned-over and turned-in upon itself on a given radius;wherein the exposed surface of the disk inside the periphery of the cylindrical lip has applied thereto a pyrotechnic composition coating layer which can be initiated by the impact of an inert projectile;and wherein a circular protective lid is snapped into place over the exposed disc surface and is held in place by the turned over and turned-in periphery of the cylindrical lip of the disc to thereby form a completed shell casing.

2. The method of claim 1, wherein the pyrotechnic layer is applied as a coating to the exposed surface of the disc and wherein the pyrotechnic composition which is used as the coating layer is made up of pyrotechnic agents in a binder composition, the binder composition being initially flowed by gravity over the exposed disc surface and then dried.

3. The method of claim 2, wherein the cardboard lid is laminated with a plastic layer so that it is water repellant.

4. The method of claim 3, wherein the cardboard lid has a thickness which is selected to allow the lid to be easily penetrated by the inert projectile.

5. The method of claim 1, wherein the flat, round exposed disc surface has a given diameter which ranges from about 35 mm to about 70 mm.

6. The method of claim 5, wherein the cylindrical turned-over and turned-in lip has a vertical height, as measured from the exposed disc surface in the range from about 3 mm to about 8 mm.

7. The method of claim 6, wherein the cylindrical turned-over and turned-in lip has a vertical height in the range from about 6.60 to about 6.66 mm.

8. The method of claim 1, wherein the thickness of the flat, exposed disc surface is on the order of 1 to 3 mm.

9. The method of claim 1, wherein the thin metal disc has a rear surface and wherein an adhesive patch is applied to the rear surface to allow the disc to be temporarily stuck to a target background surface.

10. The method of claim 1, wherein the metal disc is formed of a ferrous metal and wherein the target disc is held within an accompanying disc receiving holder, the disc receiving holder having a magnetic region for attracting and retaining the metal disc within the holder.

11. The method of claim 10, wherein the disc receiving holder is a cylindrically shaped body having a disc receiving recess for receiving the metal disc, the holder being sufficiently stiff to support the metal disc and also being re-usable.