GB1594292A

GB1594292A - Method of producing a clay pigeon

Info

Publication number: GB1594292A
Application number: GB7898/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-03-02
Filing date: 1978-02-28
Publication date: 1981-07-30
Also published as: ATA151278A; ES467427A1; SE427106B; IT1092989B; AT365114B; FR2382670A1; IT7820823A0; NL7802326A; SE7802316L; JPS53134018A; JPS6158419B2; DE2808782A1; FR2382670B1

Description

(54) METHOD OF PRODUCING A CLAY PIGEON (71) I, IB SCHREINER HANSEN, a Citizen of Denmark of Aaso, DK-5953 Tranekaer, Denmark, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a method of producing a flying target of the type commonly referred to as clay pigeons. The invention also relates to a clay pigeon obtained by said method.

The known clay pigeons are usually produced from chalk mixed in phenyl-resinous bitumen. Such clay pigeons are encumbered with serious drawbacks seen from an environmental point of view since the constituent materials are not or only very slowly decomposed in the environment and furthermore are relatively toxic and can therefore be dangerous if the remains of the clay pigeons are eaten by animals, or by pollution of the soil and/or the ground water.

Moreover, the toxicity constitutes a risk to the health of those who are employed in the production of the clay pigeons. Further, the production is relatively expensive since the mixture must be melted and compressed to the desired shape under pressure, and for some time after the manufacture the clay pigeon is still rather soft and must be cooled before it can be stacked.

Finally, such clay pigeons have been found to have an inadequate form stability since for example their shape can change if they are exposed to sun light or heat for a shorter or longer period of time.

The object of the present invention is to provide a non-toxic clay pigeon that does not impair the environment and whose strength and frangibility properties are suitably adjusted to the purpose of application, and which is not encumbered with the drawbacks known from the current clay pigeons.

It has been found that this object can be achieved by the method of the invention which is characterized in that a mixture comprising plaster (hemihydrate (CaSO4 1/2 Halo)), an amount of water constituting a large excess in relation to the amount necessary for setting the plaster, fly ash as well as one or more of the following additives: surfactants, organic binders, set-controlling agents and brittleness-promoting agents are subjected to such a compression in a mould heated to a temperature in the range of 100 to 1600C that at least part of the excess amount of water in relation to the amount necessary for setting the plaster is driven off from the mould, whereupon the clay pigeon is removed.

The invention is based on the surprising recognition that by using a large excess of water in relation to the amount necessary for setting the plaster it is possible to obtain a homogeneous mixture of the constituent materials, which can easily be divided into portions of a size adjusted to the standard weight of clay pigeons, and which can very easily be transferred to moulding tools suitably shaped and heated to a temperature in the range of 100 to 1600C and provided with a number of small apertures permitting the driving off of the excess water during the compression, substantially in the form of steam.

By the expression "a large excess" is understood an excess amount considerably exceeding any excess due to inaccuracy when mixing the required amount of water necessary to set the plaster. Preferably, at least 100% by weight excess is used in relation to the amount necessary for the setting, particularly 100-200% by weight, preferably 105 to 115% by weight.

As 100 g of CaSO4, 1/2 H2O requires 18.6 g of water for the setting with formation of CaSO4, 2 H2O, the amount of water then preferably constitutes at least 37% by weight of the amount of plaster, particularly 37 to 56%, preferably 38 to 40% by weight.

The French Patent No. 1 345 259, German Patent No. 812 414 and German Auslegeschrift No. 1 001 174 teach the application of plaster especially in the form of anhydrite in a mixture with various other substances where the plaster is set or in respect of the anhydrite is recrystallized in the presence of water or steam, to produce various moulded products, particularly building materials.

None of these publications mention clay pigeons, and as a matter of fact they emphasize that the products achieved show an improved mechanical strength over similar mixtures. As regards clay pigeons it is, as mentioned, inter alia a problem if the clay pigeons have a too great mechanical strength, and the mixtures set forth in these publications are thus unsuitable for manufacturing clay pigeons, and also their composition and manufacture deviate from those of the invention.

The mixture used comprises preferably 45 to 55% by weight of plaster, an amount of water constituting a large excess in relation to the amount necessary for setting the plaster, 1-25% by weight of fly ash, and a total of up to 5% by weight of the following additives: surfactants, organic binders, set-controlling agents and brittleness-promoting agents.

The greatest measure of certainty of imparting to the pigeon such a frangibility that it will be broken by only a few pellets and that nevertheless it is strong enough to withstand the ejection is achieved. however, with a mixture comprising 45 to 55% by weight of plaster, an amount of water constituting a large excess in relation to the amount necessary for setting the plaster, 1 to 5% by weight of fly ash and a total of up to 5% by weight of the following additives: surfactants, organic binders, set-controlling agents and brittleness-promoting agents and furthermore 1 to 5% by weight of calcium carbonate and 20 to 30% by weight of heavy spar (baryte, BaSO4).

This composition can advantageously be mixed by dissolving or suspending the additives in water, whereupon heavy spar, fly ash and chalk are admixed while stirring with a subsequent addition of plaster.

The mixture which has given the best results up to now comprises about 50% by weight of plaster, about 20% by weight of water, about 3% by weight of fly ash, about 25% by weight of heavy spar, about 3% by weight of chalk and a total of about 3% by weight of the additives mentioned, the relative weight ratio of the latter being approximately 15:10:0.5:3.

The method of the invention can be used at relatively low pressures, e.g. 75 to 200 kg/cm2, and very short periods of processing in the range of from 2 seconds or less and up to a few for example 5 seconds.

In another less preferred embodiment a mixture is used of 45 to 55% by weight of plaster, an amount of water constituting a large excess in relation to the amount necessary for setting the plaster, 15 to 25% by weight of fly ash, and a total of up to 2% by weight of the following additives: short organic fibres, surfactants, organic binders, set-controlling agents and brittleness-promoting agents which are subjected to such a compression in a mould heated to a temperature in the range of 100 to 1200C that the excess amount of water in relation to the amount necessary for setting the plaster is driven off from the mould, whereupon the clay pigeon is removed.

The mixture employed comprises advantageously about 50% by weight of plaster, about 20% by weight of fly ash, about 30% by weight of water and a total of about 1% by weight of the additives mentioned, the relative weight ratio of the latter being preferably approximately 5:5:2.5:5:1.

The compression in this embodiment is effected preferably at a pressure of 150 to 200 kg/cm2 for a period of 1 to 5 seconds.

The clay pigeon produced by the method of the invention has an extremely stable shape immediately after the production and may be stacked almost immediately.

In immediate continuation of the shaping of the pigeon is advantageously painted in a desired non-toxic colour, for example white or yellow, preferably while the pigeon is still hot because the painting makes the finished clay pigeon suitably dust-free.

As mentioned, the main components of the subject clay pigeon are the inexpensive and non-toxic materials, plaster, fly ash and water as well as preferably heavy spar and chalk.

The fly ash used is preferably fly ash from coal-burned power works, because fly ash from waste disposal plants may contain undesirable metals.

According to the invention small amounts of number of additives are also used, as is mentioned, to ensure a process that permits an unproblematic production with an exceptionally high output of a non-toxic product which is not detrimental to the environment and which has the properties desirable for clay pigeons, viz. a hardness adjusted so that on the one hand they can withstand the mechanical impacts during transport and from the throwing apparatus used, and on the other that they are so brittle or frangible that they will break when hit by pellets.

To facilitate the mixing of the components and the removal of the clay pigeons from the moulds one or more surfactants are added, for example decomposable anionic surfactants, e.g. alkylaryl sulfonates or fatty alcohol sulfates and/or soft soap.

Further additives are organic binders, e.g. bone glue, PVA-glue or corresponding non-toxic products, for example on animal or vegetable basis.

Moreover, small amounts of set-controlling agents are added according to the invention to permit a satisfactory rate of setting, which on the one hand is so slow as to make possible an intimate mixing of the starting materials and an unproblematic division into portions and transfer to the mould tools and on the other is so fast that such a mechanical strength is imparted to the clay pigeon forms, that it can be transported and, if desired, stacked or stored in any other way in continuation of the production and the optional painting.

Thus, one or more retarders of set may advantageously be added, e.g. citric acid, borax, or other retarders, for example keratin.

An accelerator of set is added if desired to offset the effect of the retarder. The ratio of accelerator to retarder may be determined by a skilled person by means of tests, and it will thus be possible to omit one of these two types in borderline cases.

To ensure that the finished clay pigeon is so brittle or frangible that it will easily break when hit by one or more pellets, a brittleness-promoting agent is added according to the invention. Particularly appropriate agents of this type are gypsum or alumn because they contribute towards making the clay pigeon more hard and brittle and also act as accelerators.

The relative ratio of the above four types of additives may vary within the upper limit of about 5% by weight of the total mixture within wide limits depending upon the specific agents used, but a particularly expedient combination is achieved, as is mentioned, if their relative weight ratio in the order stated in claim 1 and above is approximately 15:10:0.5:3.

As mentioned, a less preferred embodiment employs short organic fibres, for example lignin and/or cellulose fibres, for example in the form of pulp direct from wood or paper mills, or in the form of paper products, such as old newspapers or other waste paper, which are defibrated more or less for example in the presence of the amount of water used for the mixture before the final mixing is carried out. These fibres contribute towards imparting to the clay pigeon the desired mechanical properties, but this effect is difficult to control so that in some cases an optimum brittleness is not obtained, and the defibration also requires an extra amount of energy. For these reasons it is preferred to avoid the use of fibres, but they may be used for example in areas where defibrated pulp of fibres with low breaking strength is readily available.

If fibres are used, the ratio between the additives is in the order stated in claim 8, preferably approximately 5:5:2.5:0.5:1.

The invention will be illustrated in more detail with reference to the examples below.

Example 1 For the production of clay pigeons the following composition was used: approx. % by weight Plaster (CaSO4, 1/2 H2O 48.44 Heavy spar (BaSO4) 24.29 Chalk (CaCO3) 2.43 Fly ash 3.03 Water 19.13 Soluble anionic surfactant (about 7% aqueous "SULFONOL" R.T.M.) 0.24 Soft soap (43% aqueous solution) 1.18 Organic binder 0.97 Retarder (keratin) 0.05 Gypsum (CaSO4, 2 H2O) 0.31 100.07 The additives were suspended in water, whereupon heavy spar, fly ash and chalk were admixed while stirring and finally plaster was admixed.

After the addition of plaster and the mixing a soft homogeneous substance was obtained having a consistency resembling "Plasticine" (R.T.M.). This substance was pressed through a tube of a diameter expediently within the range of 23 to 80 mm, from which discs having a weight of about 120 g were cut. These discs were transferred to the lower portion of the moulding tool, and then compressed at a pressure of 75 to 200 kg/cm2 for a period of 1 to 2 seconds to the desired shape.

The moulding tool was heated to about 130 to 1600C and during the compression about 10 g of water escaped, substantially in the form of steam. Then the mould was opened and the clay pigeon was removed, preferably by means of discharge devices.

A clay pigeon with a stable shape and a weight of about 110 g was achieved which on standing and drying gave off a further 6 to 8 g, or so, of water whereupon it has the constant weight of about 102 to 106 g which is desirable for clay pigeons.

Example 2 For the production of clay pigeons the following composition was used: approx. % by weight Plaster (CaSO4, 1/2 H2O) 51.2 Fly ash 19.3 Water 28.5 Organic fibres 0.4 Anionic surfactant (about 7% aqueous "SULFONOL" (R.T.M.) 0.4 Organic binder (bone glue) 0.2 Citric acid 0.04 Alum 0.07 100.0 Plaster and fly ash were dry mixed separately and the other components were mixed to form a fairly homogeneous aqueous suspension.

The two mixtures were united and mixed into a soft homogeneous substance of a consistency resembling "Plasticine" (R.T.M.). This substance was pressed through a tube of a diameter expediently within the range of 23 to 80 mm, from which discs having a weight of about 136 g were cut. These discs were then one by one transferred to the lower portion of the moulding tool and then compressed at a pressure of about 150 to 200 kg/cm2 for a period of 1 to 2 seconds to the desired shape.

The moulding tool was heated to about 100 to 1200C, and during the compression about 26 g of water escaped, substantially in the form of steam, through apertures in the sides of the mould. Then the mould was opened and the clay pigeon was removed, preferably by means of discharge devices.

A clay pigeon with a stable shape and a weight of about 110 g was obtained which on standing and drying gave off a further 6 to 8 g, or so, of water, whereupon it has the constant weight of about 102 to 106 g which is desirable for clay pigeons.

The above examples may be employed for large-scale production and thanks to the very short separate operations the process is extremely suitable for continuous production, it being possible to produce several clay pigeons at the time by providing suitably shaped stations for the individual processing steps.

Tests with clay pigeons of the above composition have shown that when they are hit by pellets they break into pieces, which depending on the weather, will decompose in the course of only a few days or weeks, heavy fall of rain of course accelerating the decomposition. Even though an animal eats a piece of a broken clay pigeon its health will not be affected bcause the components are absolutely non-toxic.

To obtain good ballistic properties and a greater measure of certainty that pellets fired against them will not glance off, the top-face of the clay pigeons may be provided with pockets, for example shaped like ball segments. This is illustrated in greater detail in the drawing in which Figure 1 is a top view of a preferred embodiment of the clay pigeon of the invention, Figure 2 is a cross section of the clay pigeon shown in Figure 1 and taken along the line I-I.

The clay pigeon shown in Figures 1 and 2 comprises an annular disc whose top face has a rim portion 1 with a step-shaped profile, an upwardly convex profile section 2 and a circular recessed region 3. The top face of the convex profile section 2 is provided with a great number of closely spaced pockets 4 shaped like ball sections. The underface of the clay pigeon forms a space 5. When the clay pigeon is thrown the rim portion with the step-shaped profile serves to guide the clay pigeon during its movement along the throwing arm of the trap. This throwing arm imparts to the clay pigeon a fast spinning around the centre line of the disc.

WHAT I CLAIM IS: 1. A method of producing a clay pigeon, wherein a mixture comprising plaster (CaSO4,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Example 2 For the production of clay pigeons the following composition was used: approx. % by weight Plaster (CaSO4, 1/2 H2O) 51.2 Fly ash 19.3 Water 28.5 Organic fibres 0.4 Anionic surfactant (about 7% aqueous "SULFONOL" (R.T.M.) 0.4 Organic binder (bone glue) 0.2 Citric acid 0.04 Alum 0.07 100.0 Plaster and fly ash were dry mixed separately and the other components were mixed to form a fairly homogeneous aqueous suspension. The two mixtures were united and mixed into a soft homogeneous substance of a consistency resembling "Plasticine" (R.T.M.). This substance was pressed through a tube of a diameter expediently within the range of 23 to 80 mm, from which discs having a weight of about 136 g were cut. These discs were then one by one transferred to the lower portion of the moulding tool and then compressed at a pressure of about 150 to 200 kg/cm2 for a period of 1 to 2 seconds to the desired shape. The moulding tool was heated to about 100 to 1200C, and during the compression about 26 g of water escaped, substantially in the form of steam, through apertures in the sides of the mould. Then the mould was opened and the clay pigeon was removed, preferably by means of discharge devices. A clay pigeon with a stable shape and a weight of about 110 g was obtained which on standing and drying gave off a further 6 to 8 g, or so, of water, whereupon it has the constant weight of about 102 to 106 g which is desirable for clay pigeons. The above examples may be employed for large-scale production and thanks to the very short separate operations the process is extremely suitable for continuous production, it being possible to produce several clay pigeons at the time by providing suitably shaped stations for the individual processing steps. Tests with clay pigeons of the above composition have shown that when they are hit by pellets they break into pieces, which depending on the weather, will decompose in the course of only a few days or weeks, heavy fall of rain of course accelerating the decomposition. Even though an animal eats a piece of a broken clay pigeon its health will not be affected bcause the components are absolutely non-toxic. To obtain good ballistic properties and a greater measure of certainty that pellets fired against them will not glance off, the top-face of the clay pigeons may be provided with pockets, for example shaped like ball segments. This is illustrated in greater detail in the drawing in which Figure 1 is a top view of a preferred embodiment of the clay pigeon of the invention, Figure 2 is a cross section of the clay pigeon shown in Figure 1 and taken along the line I-I. The clay pigeon shown in Figures 1 and 2 comprises an annular disc whose top face has a rim portion 1 with a step-shaped profile, an upwardly convex profile section 2 and a circular recessed region 3. The top face of the convex profile section 2 is provided with a great number of closely spaced pockets 4 shaped like ball sections. The underface of the clay pigeon forms a space 5. When the clay pigeon is thrown the rim portion with the step-shaped profile serves to guide the clay pigeon during its movement along the throwing arm of the trap. This throwing arm imparts to the clay pigeon a fast spinning around the centre line of the disc. WHAT I CLAIM IS: 1. A method of producing a clay pigeon, wherein a mixture comprising plaster (CaSO4,

1/2 H2O), an amount of water constituting a large excess in relation to the amount necessary for setting the plaster, fly ash as well as one or more of the following additives: surfactants, organic binders, set-controlling agents and brittleness-promoting agents is subjected to such a compression in a mould heated to a temperature in the range of 100 to 1600C that at least part of the excess amount of water in relation to the amount necessary for setting the plaster is driven off from the mould, whereupon the clay pigeon is removed from the mould.

2. A method according to claim 1, wherein the mixture comprises 45 to 55% by weight of plaster, an amount of water constituting a large excess in relation to the amount necessary for setting the plaster, 1 to 25% by weight of fly ash, and a total of up to 5% by weight of the following additives: surfactants, organic binders, set-controlling agents and brittleness-promoting agents.

3. A method according to claim 2, wherein the mixture comprises 45 to 55% by weight of plaster, an amount of water constituting a large excess in relation to the amount necessary for setting the plaster, 1 to 5% by weight of fly ash and a total of up to 5% by weight of the following additives: surfactants, organic binders, set-controlling agents and brittleness-promoting agents and furthermore 1 to 5% by weight of calcium carbonate and 20 to 30% by weight of heavy spar.

4. A method according to claim 3, wherein the mixture is mixed by dissolving or suspending the additives in water, whereupon heavy spar, fly ash and chalk are admixed while stirring with a subsequent addition of plaster.

5. A method according to claim 3 or 4, wherein the mixture comprises about 50% by weight of plaster, about 20% by weight of water, about 3% by weight of fly ash, about 25% by weight of heavy spar, about 3% by weight of chalk and a total of about 3% by weight of said additives.

6. A method according to claim 5, wherein the relative weight ratio of the additives contained in the mixture is approximately 15:10:0.5:3.

7. A method according to claims 1-5, wherein the compression takes place at a pressure of 75 to 200 kg/cm2 for a period in the range of from less than 2 to a maximum of 5 seconds.

8. A method according to claim 1, wherein a mixture of 45 to 55% by weight of plaster, an amount of water constituting a large excess in relation to the amount necessary for setting the plaster, 15 to 25% by weight of fly ash and a total of up to 2% by weight of the following additives: short organic fibres, surfactants, organic binders, set-controlling agents and brittleness-promoting agents is subjected to such a compression in a mould heated to a temperature in the range of 100 to 1200C that at least part of the excess amount of water in relation to the amount necessary for setting the plaster is driven off from the mould whereupon the clay pigeon is removed from the mould.

9. A method according to claim 8, wherein the mixture comprises about 50% by weight of plaster, about 20% by weight of fly ash, about 30% by weight of water and a total of about 1% by weight of said additives.

10. A method according to claim 9, wherein the relative weight ratio of the additives contained in the mixture is approximately 5:5:2.5:0.5:1.

11. A method according to claims 8-10, wherein the compression takes place at a pressure of 150 to 200 kg/cm2 for a period in the range of 1 to 5 seconds.

12. A method of making a clay pigeon substantially as herein described with reference to, and as illustrated in, the accompanying drawings.

13. A clay pigeon, produced by the method according to any of the preceding claims.