US3884470A - Frangible target - Google Patents

Abstract

A frangible target particularly suited for use in skeet and trap shooting manufactured from sulfur and sulfur having additives such as minor amounts of n-decane, napthalene, biphenyl, ethane dithiol, sodium sulfide and iron sulfide; the target initially having a monoclinic form converting to a relatively frangible rhombic crystalline form.

Description

United States Patent 1191 Paulson May 20, 1975 [54] FRANGIBLE TARGET 3,840,232 10/1974 Ludwig 106/287 sc [76] inventor: Peter O. Paulso 212 Palisdale R9,984 12/1881 Spence 106/70 Rd. S.W., Calgary, Alberta, OTHER PUBLICATIONS Canada Fundamental Chemistry Second Ed., Andrews et a]. p. [22] Filed: Nov. 6, 1972 595, 1962.

[21] App]. No.: 303,999 I Primary ExammerTheodore Moms Related [1.8. Application Data [63] Continuation-impart of Ser. No. 199,332, Nov. 16, [57] ABSTRACT 1971, abandoned.

A frangible target particularly suited for use in skeet 52 us. (:1. 273/105.4; 106/287 so and p Shooting manufactured from Sulfur and sulfur 51 1111.01 F41j 1/00 having additives such as minor amounts of e [53] Field f Search 10 23 70 237; 423/578 napthalene, biphenyl, ethane dithiol, sodium sulfide 423 5 7; 273/1054 and iron sulfide; the target initially having a monoclinic form converting to a relatively frangible rhom- [56] References Cited bic Crystalline form- UNITED STATES PATENTS 4/1936 Duecker 106/287 SC 4 Claims, N0 Drawings FRANGIBLE TARGET This application is a continuation-in-part of application Ser. No. 199,332. filed Nov. 16, 1971, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to frangible targets and. in par ticular, relates to frangible flying targets manufactured from sulfur compositions intended to be thrown to simulate wing and target shooting such as in skeet and trap shooting.

Conventional frangible targets used in skeet and trap shooting are manufactured from a mixture of pitch and fine clay or limestone to provide a brittle albeit amor phous structure. It has been found that such targets suffer from a serious disadvantage in that a direct hit on a target by a pellet can either result in the pellet glanc: ing off the target or penetrating the target to knock out a piece of target so small that it is not observed, with the result that in either case no hit is scored.

Also, conventional frangible targets also suffer from the disadvantages of being adversely affected by moisture, by long periods of storage and by temperature variations.

SUMMARY OF THE INVENTION I have found surprisingly that targets manufactured from sulfur and from sulfur with certain additives substantially avoid the foregoing disadvantages inherent in conventional targets and provide the desirable properties of mechanical strength sufficient to withstand the stresses of handling and trapping, while having improved frangibility and imperviousness to moisture and resistance to adverse affects from long periods of storage or temperature variations.

More particularly, I have found that targets manufactured from sulfur and from sulfur with additives such as aromatic compounds having the characteristics of napthalene and biphenyl, mercaptans and their derivatives having the characteristics of ethane dithiol, sulfonic acid and sulfonate compounds, resulting as by-products of pulp and paper processes, such as for example lignin sulfonate, and iron sulfide, initially have a non-brittle crystal structure which converts to a relatively frangible crystal structure suitable for target purposes.

DESCRIPTION OF PREFERRED EMBODIMENTS Other advantages, objects and features of the invention will become apparent from the following detailed description of the method of manufacture and the description of the product.

The configurations of frangible thrown targets are well known, generally comprising a saucer shape having a thickened circular peripheral wall or rim portion and a thin central disc-like portion with a plurality of annular ribs or ridges formed thereon to provide strength to withstand handling and trapping and to capture pellets which score a hit. The frangible targets of the present invention can be made in such conventional shapes by the forming of molds suitable for injection molding, or by other techniques well known in the art.

Elemental sulfur which has a melting point of about 246F., alone or admixed with an additive, to be herein referred to as a sulfur composition", in accordance with one embodiment of the method of my invention is heated to a temperature range of from about 25 to about 40F, above the sulfur composition melting point at which temperature it is sufficiently fluid for forming into product shapes such as by injection at low pressures into a mold or by dipping a mold into a molten bath, while permitting rapid subsequent cooling for solidification. A melt temperature of about 280F. has been found particularly satisfactory for dipping or for injection into a cold mold in that the approximately one-half second cooling time available for solidification permits entrained gas bubbles to escape for the formation of a uniformly dense product.

A mold used for dipping into a melt of sulfur composition preferably has a thin conductive shell surrounding the exterior of the mold and insulated from the interior of the mold to prevent sulfur composition build-up on the mold exterior by permitting the shell to rapidly heat to melt temperature during immersion such that any solidified sulfur composition adhered to the shell will melt and drip off the mold during removal from the melt.

The resulting product initially has a monoclinic crystalline structure which is not brittle and which permits automated handling and packaging without much danger of breakage. After about four days from solidification this monoclinic structure matures by conversion to a rhombic structure, which conversion provides the important advantage of relieving internal stresses due to uneven cooling while imparting a high degree of frangibility to the target.

I have found that the rhombic structure tends to propogate fractures much more readily than the amorphous pitch solids conventionally used. For example, comparative tests were made by firing lead projectiles through targets formed of pitch and clay and identically-shaped targets formed of sulfur compositions and it was found that one or more lead pellets could be fired through the conventional targets without breaking the targets or forming fractures which would cause the targets to break while spinning through the air, while in no one instance was it possible to fire a pellet through sulfur composition targets without either shattering the targets or causing such a multiplicity of fractures that the targets could not support their own weight or remain intact while spinning in air.

Elemental sulfur alone can have sufficient structural strength for certain target applications by increasing the cross-section, i.e. the thickness, of the targets. However, it was found that the presence of certain additives admixed with the sulfur substantially increased the strength of the targets to render the targets more suitable for trapping while obviating the need for increase of target cross-section or weight and while not impeding frangibility. Table 1 following illustrates the effect on mechanical strength of certain additives with sulfur relative to Pure Laboratory Grade sulphur which was given an arbitrary value of 1.00.

TABLE I] RATIO OF STRENGTH OF SULFUR SAMPLE WITH ADDITIVE TO STRENGTH OF PURE LABORATORY GRADE SAMPLE TABLE I-Continued RATIO OF STRENGTH OF SULFUR SAMPLE WITH ADDITIVE TO STRENGTH OF PURE LABORATORY GRADE SAMPLE *Ratio of strength of sample to strength of PLG sample. PLG sample strength is defined as the load applied by a knife edge to the mid-point ofa 6 inches X inch X 3 inches PLG sample. supportcd at the ends in a Hunsfield tensometer, which caused failure of the sample (82 1b.).

It will be evident from Table 1 that the addition of any one of 0.05 to 1.00% n-decane, 0.05% biphenyl, 0.1% ethane dithiol, 0.05 to 0.1% napthalene, 0.1% sodium sulfide and 0.1% iron sulfide to sulfur effectively increased the strength of the targets produced therefrom.

Of the foregoing additives, iron sulfide, which is inex pensive and easily mixed with the sulfur, provided adequate strength to the sulfur for normal handling and trapping of targets when present in the range by weight of from 0.05 to 0.30%, preferably 0.1%, with industrial bright grade sulfur. The aromatics, represented by for example napthalene and biphenyl, in amounts by weight of 0.02 to 0.2%, preferably 0.05 to 0.1% in sulfur, provided a product having a bright yellow color and resistant to fracturing due to temperature changes.

These admixtures of certain additives with sulfur provided a suitable combination of strength and fracture propogation. The breakdown characteristics of certain combinations, as a ratio of large particles to fines, is shown in Table II.

TABLE II structure with the characteristics of a plastics composition, i.e. with a relatively resilient structure. This polymerized structure converts to a relatively frangible rhombic crystalline structure in about 3 to 4 days.

Polymerization of the sulfur composition, including sulfur without additives, provides the important advantage of permitting improved ease of handling and packaging immediately after manufacture while retaining projectile frangibility after conversion to the rhombic crystalline structure.

The color of the targets of the present invention, essentially a tan-yellow color for the sulfur-iron sulfide composition and a bright yellow for the sulfur-aromatic composition, provides another important advantage in that these colors show up better against most backgrounds than do conventional targets which are all black or partly black. Also, the breaking of a target by a hit results in the formation of a dense cloud of readily visible dust, due to the target color and multiplicity of fragments produced by the propagation of fractures, to facilitate and improve the accuracy of scoring on a trap or skeet range.

What we claim as new and desire to protect by Letters Patent of the United States is:

l. A saucer-shaped, thin-walled, frangible target for use as a flying target formed from a sulfur composition selected from the group consisting sulfur with additives having the strength characteristics of n-decane, napthalene, biphenyl, ethane dithiol, lignin sulfonate, sodium sulfide or iron sulfide admixed therewith whereby said target initially has a monoclinic crystalline structure which matures to convert to a rhombic crystalline structure.

2. A saucer-shaped, thin-walled, frangible target for use as a flying target formed by molding sulfur or a molten sulfur composition selected from the group consist- BREAKDOWN CHARACTERISTICS OF THE SAMPLES Ratio of the weight percent having a particle 0.02 inches.

Number of tumbles.

Figure in parentheses is the weight size 025 inches to the weight per cent having a particle size per cent having a particle size 025 inches plus the weight per cent having a particle Size 0.02 inches i.e. difference from 1007: yields portion of sample between the two arbitrary limits It will be noted from Table II that the presence of adg of Sulfur With I0 1 114603116, Sulfur With ditives in sulfur in the form of flakes and bars tested did not significantly alter the ratio of large particles to tines. Accordingly, all articles made from the various sulfur compositions retained good shatterability characteristics although mechanical strength had been increased as shown in Table I.

In accordance with another embodiment of my invention, the sulfur composition is heated to and molded at a temperature of at least 350F. and rapidly cooled upon molding to solidification. I have found that rapid cooling of the sulfur composition melt to solidification, such as within 30 seconds of initiation of cooling, results in a product having a polymeric-like long chain 0.02 to 0.2% napthalene, sulfur with 0.05% biphenyl, sulfur with 0.1% ethane dithiol, sulfur with 0.1% sodium sulfide, and sulfur with 0.05 to 0.3% iron sulfide, by weight, whereby said molded sulfur composition initially has a monoclinic crystalline structure which matures by conversion to a rhombic crystalline structure.

3. A saucer-shaped, thin-walled, frangible target as claimed in claim 1, in which said sulfur composition is sulfur with O. 1% by weight iron sulfide.

4. A saucer-shaped, thin-walled, frangible target as claimed in claim 1, in which said sulfur composition is sulfur with 0.05 to 0.1% napthalene.

Claims (4)

1. A SAUCER-SHAPED, THIN-WALLED, FRANGIBLE TARGET FOR USE AS A FLYING TARGET FORMED FROM A SULFUR COMPOSITION SELECTED FROM THE GROUP CONSISTING SULFUR WITH ADDITIVES HAVING THE STRENGTH CHARACTERISTICS OF N-DECANE, NAPTHALENE, BIPHENYL, ETHANE DITHIOL, LIGNIN SULFONATE, SODIUM SULFIDE OR IRON SULFIDE ADMIXED THEREWITH WHEREBY SAID TARGET INITIALLY HAS A MONOCLINIC CRYSTALLINE STRUCTURE WHICH MATURES TO CONVERT TO A RHOMBIC CRYSTALLINE STRUCTURE.

2. A saucer-shaped, thin-walled, frangible target for use as a flying target formed by molding sulfur or a molten sulfur composition selected from the group consisting of sulfur with 0.05 to 1.0% n-decane, sulfur with 0.02 to 0.2% napthalene, sulfur with 0.05% biphenyl, sulfur with 0.1% ethane dithiol, sulfur with 0.1% sodium sulfide, and sulfur with 0.05 to 0.3% iron sulfide, by weight, whereby said molded sulfur composition initially has a monoclinic crystalline structure which matures by conversion to a rhombic crystalline structure.

3. A saucer-shaped, thin-walled, frangible target as claimed in claim 1, in which said sulfur composition is sulfur with 0.1% by weight iron sulfide.

4. A saucer-shaped, thin-walled, frangible target as claimed in claim 1, in which said sulfur composition is sulfur with 0.05 to 0.1% napthalene.