US3580579A

US3580579A - Electric target apparatus for indicating hit points

Info

Publication number: US3580579A
Application number: US792340A
Authority: US
Inventors: Armin Scharz; Oskar Scharz
Original assignee: Polytronic AG
Current assignee: Polytronic AG
Priority date: 1968-01-19
Filing date: 1969-02-21
Publication date: 1971-05-25
Anticipated expiration: 1988-05-25
Also published as: SE333694B; GB1197151A; CH487388A

Abstract

A target apparatus for automatically indicating the hit point of a projectile comprises a plurality of target elements mounted one behind the other, each element including two electrically insulated parallel sheets of electrically conductive material and included in an electric circuit, the distance between the two conductive sheets being less than the length of a projectile. At least two of the target elements are situated in planes which are inclined one relative to the other, whereby said relatively inclined target elements, when traversed by a projectile, produce pulses in timed sequence which are used to determine the hit point of the projectile on the target.

Description

United States Patent [72] inventors Armin Scharz;

Oskar Scharz, lnterlaken Bern,

Polytronic S. A. Saint-Aubin (Neuchatel, Switzerland) [73] Assignee {32] Priority Jan. 19, 1968 [33] Switzerland 861/68 [54] ELECTRIC TARGET APPARATUS FOR [56] References Cited UNITED STATES PATENTS 3,004,763 11/1961 Knaff 273/102.2A 3,487,226 12/1969 Yetter et al 273/1022 Primary Examiner-Anton O. Oechsle Assistant ExaminerMarvin Siskind Attorney-Ostrolenk, Faber, Gerb & Soffen ABSTRACT: A target apparatus for automatically indicating the hit point of a projectile comprises a plurality of target elements mounted one behind the other, each element including two electrically insulated parallel sheets of electrically conductive material and included in an electric circuit, the distance between the two conductive sheets being less than the length of aprojectile. At least two of the target elements are situated in planes which are inclined one relative to the other, whereby said relatively inclined target elements, when traversed by a projectile, produce pulses in timed sequence which are used to determine the hit point of the projectile on the target PATENTEU HAY25 |97l 3; 589,579

sum 1 OF 3 PATENTEU m2 5 Ian sum 3 [1F 3 ELECTRIC TARGET APPARATUS FOR INDICATING HIT POINTS This invention relates to target apparatus and associated electric circuitry for use in firearm target practice.

ln prior US. Pat. application Ser. No. 638,692 filed May 2, 1967, now U.S. Pat. No. 3,529,828, a shooting target is described having at least two electrically insulated, but conductive sheets. These sheets are spaced apart for a distance less than the length of the projectile, so that upon passage of a projectile through the target a momentary electric connection between the two sheets is established. A source of electric current and a transformer are connected in series with the two conductive sheets, Each time a projectile establishes a momentary electrical connection between the two sheets, a pulse is generated in the secondary of the transformer and is transmitted to a recorder and evaluated. After passage of the projectile the two conductive sheets are again electrically separated.

One of the two conductive sheets can be divided into a plurality of zones which are electrically insulated from each other, for example into a central circular zone, corresponding to the field of fire of a decimal target and several annular zones disposed concentrically about the central zone. With such an arrangement it is possible to obtain a score indication which indicates at which distance from the center of the target the projectile has hit the target.

A further known arrangement of a target comprises a third conductive layer which, for example, is divided into a plurality of rectangular sections. Such an arrangement not only enables the score to indicate the distance of a hit from the center of the target, but also the approximate position of the hit on the target.

In such targets the conductive layer of each zone and of each section is connected by means of an electrical conductor to a terminal, and these conductors also are situated at least partially in the field of fire. The conductors accordingly may also be hit by projectiles and may be damaged. For this reason, they are so formed as to be able to operate even if hit by a plurality of projectiles. Further, in such known target, a fine subdivision of the indication, as required for example with a decimal or even a centesimal target, are difficult to realize. In the latter case, more than one hundred connections to each shooting target would have to be provided, and each of these connections would have to be associated with an evaluation circuit.

The object of the present invention is to provide target apparatus which can signal the hits of the projectile with a very fine subdivison, and notwithstanding is of simple construction.

The target apparatus according to the invention comprises a plurality of target elements mounted one behind the other, each element including at least two electrically insulated parallel sheets of electrically conductive material, each conductive sheet being connected to a terminal included in an electric circuit whereby said two conductive sheets of each target element are temporarily electrically connected when a projectile penetrates the two sheets and the respective circuit will be closed, at least two of said target elements being situated in planes inclined with respect one another, whereby said relatively inclined target elements, when traversed by a projectile, produce pulses in timed sequence, the time interval between the pulses being dependent on the position of the hit point of the projectile on the target.

The invention will now be more fully explained by the following specification, reference being had to the accompanying drawings, in which:

FIG. 1 is a front view of a decimal target provided with a socalled -point-graduation;

FIG. 2 is a sectional view taken along line Il-ll of FIG. 1;

FIG. 3 is a perspective view of the basic structure of an other form of target;

FIG. 4 shows a device for indicating the position of the hit point;

FIG. 5 is a sectional view through a further embodiment of a target in accordance with the present invention;

FIG. 6 shows the basic electrical circuit for determining and indicating the hit point for a target of FIGS. 1 and 2;

FIG. 7 is a diagram showing the kind of pulses which are produced in the different target elements;

FlG. 8 is a diagram showing the form of a pulse train which transmits the position of the hit point from the target to the shooting stand; and

FIG. 9'is a schematic view of an embodiment of a target for determining the value of the score and the position of the hit point.

Referring to the drawings, FIG. 1 shows a first embodiment of a target which can generate electric pulses for determining the position of the hit point. In this target a sheet of paper 2, having printed thereon the pattern of a 10-point or decimal target is stretched over and fixed on a frame 1. A supposed hit point ofa fired projectile has been designated by 3.

As is apparent from FIG. 2 the target comprises a sheet of paper 2 on the front side as well as three

target elements

4,5 and 6 mounted behind the sheet 2. Each target element comprises a pair of electrically insulated

conductive sheets

7 and 8, 9 and 10, 11 and 12, respectively, extending over the whole target cross section. The thickness of each

insulating sheet

13, 14 and 15 provided between said conductive sheets of each pair is smaller than the length of the projectile which will be shot on the target.

The conductive sheets 7l2 may be made of thin metal foil or ofan electrically conductive rubber composition. The insulating sheets l3, l4 and 15 are preferably made of sponge rubber or foamed plastic material. On the back side of each second

conductive layer

8, 10 and 12 is fixed by means of a suitable adhesive further protective sheets l6, l7 and 18, respectively. These protective sheets serve to prevent the second conductive sheet of each target element from being pulled away by the projectile.

Due to the fact that the distance between the two conductive sheets of each target element is smaller than the length of the projectile, a momentary electric connection is established between the two sheets each time a projectile which is usually made of metal, is penetrating through them. This electrical connection is interrupted after the projectile has completely traversed the target element. Due to their elasticity, the conductive rubber sheets 7 and 8 return after the passage of the projectile substantially to their original state, so that even in the case where a plurality of projectiles would hit the target element at exactly the same place a short electric contact during the passage of the projectiles through the target element will be established.

The sheet of paper 2 and the second target element 5 are mounted in parallel planes, i.e. they are equidistant over their entire surface, the distance between them being substantially greater than the length of a projectile. The first target element 4 is mounted in front of the second target element 5 and inclined with respect thereto, as shown in FIGS. 2 and 3, the upper edge 19 of the target element 4 being parallel with the upper edge 20 of target element 5 (FIG. 3). The third target element 6 is also inclined with respect to target element 5, while its side edge 21 remains parallel to the side edge 22 of target element 5. The holes produced by a projectile penetrating the target are designated in the paper sheet 2 by 3 and in the

different target elements

4, 5 and 6 by 3, 3" and 3", respectively. Spacers 2328 of different length are used for holding the target elements 4-6 in their respective positions as described.

As shown in FIG. 6, each of said conductive sheets is provided with a

terminal

29, 30, 31, 32, 33 and 34 respectively, arranged outside the field of fire. The

terminals

29 and 30 of the conductive sheets 7 and 8 of the first target element 4 are connected in series to a voltage source 35 and to the primary winding of a transformer 36. As soon as a projectile penetrates through target element 4 the aforementioned electric circuit is closed momentarily and a current passes in this circuit. This current induces at the terminals of the secondary winding of transformer 36 a short pulse which is fed to the input terminal 39 of a transducer 42. Upon penetration of the

target elements

5 and 6 by the .projectile further pulses are produced in a similar manner in the secondary windings of

transformers

37 and 38. These pulses are of course displaced in time since the projectile cannot penetrate at the same time through all three of said target elements which are mounted one behind the other.

The three

pulses

43, 44 and 45 produced in the secondary windings of transformers 36-38 and shown in FIG. 7 will be transformed in the transducer 42, to a pulse sequence shown in FIG. 8, whereby the first flank 46 corresponds to the front flank of pulse 43,flank 47 to the front flank of pulse 44 and flank 48 to the front flank of pulse 45. This pulse sequence is fed from the output 49 of the transducer to a transmitter 50 and from the transmitter through a lead 51, which can be the lead of a hitherto used and known signal device (e.g. a bell wire), to a receiver 52 in the shooting stand. This receiver will analyze the signal and feed it to an indicating apparatus 53.

The position of the

target elements

4 and 6 with respect to the target element 5 is such that the centers of

elements

4 and 6 are equidistant from the center of target element 5. The angles of inclination of both

target elements

4 and 6 with respect to the intermediary target element 5 are identical.

Supposing that a projectile is penetrating through the centers of all three

target elements

4, 5 and 6, there will be produced a pulse sequence similar to that shown in FIG. 8, however, the distance between the

flanks

46 and 47 would be the same as the distance between the

flanks

47 and 48. If furthermore it is supposed that the velocity of the projectile remains substantially constant, it is possible to deduce the Y- coordinate 55 (FIG. 4) of the hit point from the length of the positive part of the pulse train and accordingly the X-coordinate 54 of the hit point from the negative part of the impulse train. These coordinates can be reproduced on the indicating apparatus (FIG. 4). The hit point 3 corresponds with the point of intersection of these two coordinates.

In order to take into account the different velocities of projectiles fired with different kinds of firearms it is possible to use, besides one target element 5, an additional similar target element which has to be mounted in parallel relationship to said first element 5, also between the

target elements

4 and 6, and preferably at a distance from the element 5 which is equal to the distance between the centers of

elements

4 and 5. In this case there will be produced four pulses, instead of three as represented in FIG. 7, the distance between the second pulse and the third pulse then furnishing a reference value dependent upon the velocity of the projectile, and v'vhich can serve for the evaluation. If for example all three distances between the four pulses are identical, this would mean that the hit point is exactly in the center of the target.

A further embodiment of a target according to the invention is shown in FIG. 5. In this form a first target element 55 is mounted just behind the paper target 2 in the frame 1. A second target element 56 extending parallel to said first element 55 is mounted at a distance therefrom which is greater than the length of the projectile. A further target element 57 having at least partially the form of a cone surface is arranged behind said second target element 56. The distance between the

target elements

55 and 56 is the same as the distance between the edges of the conical target element and the element 56, while the distance between the center of element 56 and the center ofelement 57 is four times the said aforementioned distance. This means, in the case where the three pulses produced when a projectile penetrates through the target elements are mutually equidistant, that: the hit point of the projectile is in a zone near the edges of the target, while in the case where the distance between the second pulse and the third pulse is four times greater than the distance between the first pulse and the second pulse, the hit point is exactly in the center of the target. This type of target enables to evaluate the distance of the hit point from the center of the target by simply comparing the differences in time of the pulses produced and taking into account the velocity of the projectile. However, this kind of target along (FIG. 5) does not permit to locate the actual position of the hit point with respect to the center of the target.

It is also possible to use a target element of the type of element 57 but which, viewed in transverse section, is curved in such a manner that the tangent lines to the curve near its center are much more inclined with respect to the other flat or plane target elements than the tangent lines in the zones near its edges. By means of such a curved target it is possible to increase the accuracy of indication in the central portion of the target.

In order that the target of FIG. 5 can also be used for indicating the position of the hit point, it is possible to provide two inclined plane target elements similar to the

target elements

4 and 6 shown in FIG. 3, or to add a target element whose conductive sheets are subdivided into strips, whereby the strips of one conductive sheet are arranged at right angles to the strips of the other conductive sheet, each strip being furthermore provided with an electric connection for deter mining the position of the hit point.

In a further embodiment, represented in FIG. 9, one of the two conductive sheets ofa target element 55 is subdivided into twelve sectors 58-69, each being electrically insulated from the others. Terminals 708ll are provided for each sector. The remaining part of the construction and arrangement of the

target elements

55, 56 and 57 of this target is similar to that of the target represented in FIG. 5.

That conductive sheet of target element 55 which is not subdivided in sectors is connected to the primary winding of a transformer 82 and this latter to one terminal of a voltage source 83. Each single sector 58-69 is connected to the primary winding of one ofa plurality of transformers 84-95 (of which only a few are represented), these primary windings being connected in turn to the other terminal of the voltage source 83. lfa projectile penetrates through the sheet of paper 2, e.g. 96, it produces a hit point 96' in target element 55, a hit point 96" in target element 56 and a hit point 96" in target element 57.

When the projectile is penetrating through target element 55 the circuit between the voltage source 83, the transformer 82, the not-subdivided conductive sheet of target element 55, the sector 63, the transformer and back to the voltage source 83 will be momentarily closed, thereby inducing a pulse in each of the secondary windings of transformers 82 and 90. The pulse produced in transformer 90 s fed to a coder 98 for identification. The latter produces an electric signal which corresponds to the approximate direction with respect to the center of the target, in which the hit point 96 has been found.

The primary windings of two transformers 99 and are connected in series each with a terminal of the

target elements

56 and 57, as well as with the voltage source 83. The current pulses produced in the

transformers

82, 99 and 100 when a projectile penetrates through the

target elements

55, 56 and 57 are inducing pulses in the secondary windings of these transfonners, which are fed to the time measuring instrument 97. The time differences between these pulses permit to determine the distance of the hit point 96 from the center of the target.

The signals appearing at the output terminals I01 of the time measuring instrument 97 and at the output terminals of the coder 98 are transmitted to the shooting stand, where they are analyzed and rendered visible by an optical indicating device.

The voltage of the voltage source 83 is selected high enough, so that any possible layer of grease or any oxidation layer on a projectile is traversed. The output of the voltage source is preferably selected so high that deformations of the conductive sheets, caused by the projectile, which could produce a continuous short which are fused automatically. In this manner the self-regeneration of the target elements is guaranteed.

A target as shown and described with respect to FIG. 9 permits an exact indication of the score on a IOO-point or centesimal target and at the same time a substantially correct indication of the position of the hit point.

The electrical connection made by the projectile between the electrically conductive sheets of each of the target elements is interrupted after the projectile has traversed said element. However, it is possible that a conductive bridge of electrically conductive material remains between the conductive sheets. The result of such a bridge would be that a further projectile could not produce a pulse in the winding of the associated transformer. In order to avoid such a disadvantage the output of the voltage source is selected so that it is able to fuse any of such remaining bridge. The conductive layers of each target element are thus always electrically insulated one from the other as soon as the projectile has left the target ele ment and the target is again ready for indicating the next hit. These explanations clearly show that the target of the present invention is self-regenerating if this should be necessary.

The target can be enclosed by front and rear protective layers, which are preferably of waterproof or water-repcllant material, e.g. of a plastic material. If the electrically conductive sheets are made of a conductive rubber composition and are mounted on insulated layers of elastic or plastic material e.g. of foamed polyurethane or polyvinylchlorid, the holes produced by the projectile will automatically close, at least partially, due to the elasticity of this material, thereby substantially increasing the life, of the target.

We claim:

1. Target apparatus for automatically indicating the hit point of a projectile, comprising a plurality of target elements mounted one behind the other, each element including at least two electrically insulated parallel sheets of electrically conductive material; each conductive sheet being connected to a terminal included in an electric circuit whereby said two conductive sheets of each target element are temporarily electrically connected when a projectile penetrates the two sheets and the respective circuit is closed, at least two of said target elements being situated in planes inclined with respect to one another, whereby said relatively inclined target elements, when traversed by a projectile produce pulses in timed sequence, the time interval between the pulses being dependent on the position of the hit point of the projectile on the target, the full surface area of each of said target elements being spaced from the full surface area of adjacent target elements without lines of intersection, whereby said pulses produced by a projectile traversing said target elements always appear in a fixed sequence.

2. Target apparatus as claimed in claim 1, comprising three plane target elements, wherein the second element is mounted in a plane substantially at right angles with respect to the path of target projectile, the first element, for determining the ordinate of the hit point, being turned respect a horizontal axis to a position in which it is inclined with respect to the plane of said second element, and the third element, for determining the abscissa of the hit point, being turned about a vertical axis to a position in which it is inclined with respect to the plane of said second element.

3. Target apparatus as claimed in claim 2, comprising a fourth target element for determining the velocity of the projectile and positioned in a plan parallel to the plane of said element which is arranged substantially at right angles to the path of the projectile.

4. Target apparatus as claimed in claim 1, comprising two target elements provided for determining the velocity of the projectile, each element being situated in a plane substantially at right angles with respect to the path of the projectile, and a further target element having at least partially the shape of a cone surface and mounted in front of or behind the said other two target elements for determining the distance of the hit point from the center of the target.

5. Target apparatus as claimed in claim 4, in which an electrically conductive sheet of one of said target elements is subdivided into a plurality of sectors each being electrically insulated from the others and each being connected to a terminal, thereby permitting to determine the position of the hit point.

6. Target apparatus as claimed in claim 1, comprising transformer means for connecting each of said conductive sheets to a voltage source, a pulse changing device for lengthening the short electric pulses produced when a projectile passes through said sheets, and an indicator device for indicating the lengthened pulses.

7. Target apparatus as claimed in claim 6, in which one terminal of each of said conductive sheets is connected to one terminal of a voltage source and the other conductive sheets are connected each by the intermediary of a transformer to the other terminal of said voltage source to thereby produce an electric pulse when a projectile is penetrating through a tar get element, means being provided to compare the time intervals between these pulses and operate a device for localizing the hit point.

8. Target apparatus as claimed in claim 7, and comprising a target including at least three flat target elements, a trans ducer to transform the three pulses produced into a pulse train which is transmitted from the target to a shooting stand for being analyzed, and an indicating device for rendering visible the coordinates of the hit point.

9. Target apparatus as claimed in claim 8, and comprising a fourth target element arranged in a plane substantially at right angles with respect to the path of the projectile, the pulse produced by this fourth element when traversed by a projectile being used for determining the velocity of the projectile and for correcting the said pulse train in order to increase the accuracy ofthe indication.

10. Target apparatus as claimed in claim 1, comprising two flat parallel target element and a third target element in the shape of a cone surface, means being provided for comparing the time intervals between the first two pulses and between the second and the third pulse to determine the distance of the hit point from the center of the target, and for transmitting a signal corresponding to this. time interval ratio to the shooting stand.

11. Target apparatus as claimed in claim 10, in which one of the conductive layers of one of the said pair of parallel target elements is subdivided into sectors, each of the said sectors being connected through additional transformers to the said voltage source, the pulses produced in these transformers being converted by a position-finding apparatus and the output signal of this apparatus being transmitted to the shooting stand where it is made visible for indicating the approximative hit point position.

12. Target apparatus as claimed in claim 6, in which the output of said voltage source is great enough to fuse conductive bridges remaining between the said sheets after penetration of a projectile, so as to regenerate the target.

Claims

1. Target apparatus for automatically indicating the hit point of a projectile, comprising a plurality of target elements mounted one behind the other, each element including at least two electrically insulated parallEl sheets of electrically conductive material, each conductive sheet being connected to a terminal included in an electric circuit whereby said two conductive sheets of each target element are temporarily electrically connected when a projectile penetrates the two sheets and the respective circuit is closed, at least two of said target elements being situated in planes inclined with respect to one another, whereby said relatively inclined target elements, when traversed by a projectile produce pulses in timed sequence, the time interval between the pulses being dependent on the position of the hit point of the projectile on the target, the full surface area of each of said target elements being spaced from the full surface area of adjacent target elements without lines of intersection, whereby said pulses produced by a projectile traversing said target elements always appear in a fixed sequence.

7. Target apparatus as claimed in claim 6, in which one terminal of each of said conductive sheets is connected to one terminal of a voltage source and the other conductive sheets are connected each by the intermediary of a transformer to the other terminal of said voltage source to thereby produce an electric pulse when a projectile is penetrating through a target element, means being provided to compare the time intervals between these pulses and operate a device for localizing the hit point.

8. Target apparatus as claimed in claim 7, and comprising a target including at least three flat target elements, a transducer to transform the three pulses produced into a pulse train which is transmitted from the target to a shooting stand for being analyzed, and an indicating device for rendering visible the coordinates of the hit point.

9. Target apparatus as claimed in claim 8, and comprising a fourth target element arranged in a plane substantially at right angles with respect to the path of the projectile, the pulse produced by this fourth element when traversed by a projectile being used for determining the velocity of the projectiLe and for correcting the said pulse train in order to increase the accuracy of the indication.

10. Target apparatus as claimed in claim 1, comprising two flat parallel target element and a third target element in the shape of a cone surface, means being provided for comparing the time intervals between the first two pulses and between the second and the third pulse to determine the distance of the hit point from the center of the target, and for transmitting a signal corresponding to this time interval ratio to the shooting stand.