# Patent

## Title
Joint for bullet traps

## Abstract

An improved joint utilizes a facing strip which is configured to extend away from a pair of plates held by the facing strip as one moves toward the middle of the facing strip. When the steel plates are disposed at an angle to one another, the facing strip is preferably straight. When the steel plates are parallel, the facing strip is preferably bent to extend toward the plates as one moves out from the middle of the facing strip and toward the lateral edges.

## Background
RELATED APPLICATIONS
The present application is a continuation of U.S. patent application Ser. No. 09/942,112, filed Aug. 28, 2001, which claims the benefit of U.S. Provisional Application No. 60/228,371, filed Aug. 28, 2000.


BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to joint strips which are used on bullet traps. More particularly, the present invention relates to such joint strips which reduce the risk of splatter through between two walls of a bullet trap and which lessen the cost of manufacturing the joint strips.
2. State of the Art
In order to maintain proficiency in the use of firearms, it is common for law enforcement officers and sportsmen to engage in target practice. In conventional target practice, a target, i.e. an outline of a person or animal is held before a bullet trap. The bullet receives bullets fired at the target and contains the bullet so that it may be retrieved and recycled.
Any steel bullet trap, however, requires a joint where two ends of a section meet. This joint has traditionally been made in the manner shown in FIGS. 1 and 2. A bullet trap wall 8 or 8′ is formed by a flat strip of steel 10 is used for the front side facing the shooter. The strip 10 typically either has bolts 12 welded to the back side, or countersunk holes 14 for bolts to drop through. A washer 16 or leg (not shown) is used on the back side in conjunction with a nut 20 to secure a bolt 22. As the nut 20 is tightened on the bolt 22, the plate 10 and washer 16 or leg 18 pinch two adjoining pieces of steel plate 26 together. During this process, the plate 10 and the washer 16 or leg 18 are disposed generally parallel with the steel plates 26.
Such configurations have several problems. First, the vibration which accompanies a round hitting a steel plate eventually causes the weld to fail, thereby allowed the welded bolts break off. While bolts placed in countersunk holes generally do not break off, it is difficult to manufacture joints with countersunk holes.
Yet another problem with both of these configurations, is that the front strip can eventually curve away from the pieces of steel plate and increase the risk that a bullet will pass through the space between the steel plates 26. The resulting splatter through can be dangerous to those in the area. Additionally, it may allow lead bullets outside of the range where they may leach lead into the environment.
Thus, there is a need for a new method of forming joint strips. Such a configuration should be less susceptible to breaking of bolts and less expensive/difficult than countersinking bolts.
SUMMARY OF THE INVENTION
Thus, it is an object of the present invention to provide an improved bullet joint strip and method for making the same.
The above and other object of the invention are achieved by a bullet joint strip which can be more readily attached without breaking and which can decrease the risk of splatter through. In accordance with one aspect of the invention, at least one, and typically a plurality of brackets are attached to the back of a facing strip. This is typically accomplished by welding the brackets to the facing strip.
The brackets are configured to receive an end of the bolt so that the bolt can be tightened to bring the facing strip into secure engagement with adjacent steel plates forming the joint. Because a much larger area of the bracket can be welded to the facing strip than is typically done with the head of a bolt, the risk that the weld will brake is significantly reduced.
In accordance with another aspect of the present invention, the facing strip is beveled to that it has two outwardly and rearwardly sloping walls. As the bolt of the joint strip is tightened, the pitched nature of the facing strip causes the ends of the facing strip to come into contact with the adjacent plates forming the joints. Because the ends of the facing strip first engage the plates, the risk that the ends will curl and pull away from the plates is significantly reduced. To the contrary, the ends of the facing strip tend to be in a compression state against the plates, further reducing the risk of splatter through.
In accordance with still yet another aspect of the present invention, the a flat facing plate is used in conjunction with an angle joint plate to minimize bullet impacts on the angle joint plate and thereby reduce the risk of splatter through.



BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description presented in connection with the accompanying drawings in which:
FIG. 1 shows a cross-sectional view of a bullet trap joint made in accordance with the teachings of the prior are wherein the head of a bolt is welded to a facing strip;
FIG. 2 a cross-sectional view of an alternate embodiment of a prior art bullet trap joint, wherein the bolt is positioned in a countersunk hole;
FIG. 3 shows a cross-sectional view of a bullet trap joint made in accordance with the teachings of the present invention;
FIG. 4 shows a top view of a joint for holding plates in a perpendicular arrangement in accordance with the present invention;
FIG. 5 shows a rear view of the joint strip shown in FIG. 3;
FIG. 6 shows a side view of the facing plate shown in FIG. 4;
FIG. 6A shows a rear view of the facing plate shown in FIGS. 4 and 6;
FIG. 6B shows and end view of the facing plate shown in FIGS. 6 and 6A;
FIG. 7 shows a side view of the angle joint shown in FIG. 4;
FIG. 7A shows another side view of the angle joint of FIG. 4; and
FIG. 7B shows and end view of the angle joints of FIGS. 4, 7 and 7A.



DETAILED DESCRIPTION
Reference will now be made to the drawings in which the various elements of the present invention will be given numeral designations and in which the invention will be discussed so as to enable one skilled in the art to make and use the invention. It is to be understood that the following description is only exemplary of the principles of the present invention, and should not be viewed as narrowing the pending claims.
Referring to FIG. 3, there is shown a cross-sectional view of a joint, generally indicated at 30, made in accordance with the principles of the present invention. As mentioned above, the joints of the prior art suffer from several problems. One significant problem is that welded bolt heads as used in the prior art have a tendency to brake. The bolt heads provide relatively little area to form a weld and are subject to vibration caused by bullets hitting the bullet trap.
Another problem with the prior art is that forming countersunk holes in plate steel or other bullet resistant materials is expensive and time consuming. Yet another problem with both alternate configurations of the prior art is that the lateral edges of the facing strip have a tendency to curl up, weakening support for the associated plates and increasing the risk of splatter through.
These problems are resolved by the joint 30 which is shown in FIG. 3. The joint 30 has a bent facing strip 34 which extends away from the wall toward the middle of the strip. In other words, the joint strip has two outwardly and rearwardly sloping walls 34a from a central longitudinal axis. Preferably, the bend provides and angle of about 12.5 degrees.
The bend in the facing strip 34 prevents the strip from curving away from the steel plates 26 and keeps the lateral edges 34b of the facing strip engaging the plates. Because of the tight engagement, the facing plate 34 is less likely to let small bullet fragments pass through opening between the plates 26.
The joint strip 36 formed by the facing plate 34 also has a bracket 38 welded to the back side. The bracket 38 is configured with an opening 38a (FIG. 5) so that a bolt 42 slides into this bracket. The bolt 42 also engages a backing plate or a washer 46 to secure the facing strip to the plates 26. This makes it simple to replace a broken bolt without replacing the entire strip 34.
The bracket 38 preferably has more than two inches of weld coverage attaching it to the facing strip 34. This is contrast to the small amount of weld coverage provided by the head of a bolt and prevents the bracket 38 from breaking away from the strip 34 due to the vibrations caused when a round of ammunition impacts the joint 30.
The washer 46 on the back side of the plates 26 is preferably over-sized to give greater pinching force on the plates 26 when the nut 50 is tightened. While a backing plate can be used if desired, the secure engagement created by the beveled facing plate 34 is sufficiently strong that a backing plate is generally not necessary. Backing plates may be desirable, however, if high powered rounds are being used.
FIG. 4 shows a method for forming a joint 60 with similar advantages when the plates 26 are disposed perpendicular to one another. Typically, an angle joint 64 is used to hold the two pieces of steel plate 26 together. The angle joint 64 has openings 90 through which bolts 92 extend. Tightening the bolts pinches the ends of the plates between the angle joint 64 and a washer or backing strip 96.
Unfortunately, the angle joint 64 can suffer the same problems as the flat joint discussed in FIGS. 1 and 2. These problems are resolved by providing a facing strip 68 which forms a flat plate. A bolt 72 is attached to the flat plate either by welding or by a bracket such as that discussed with respect to FIG. 3.
A channel 76 is formed in the angle joint 64 to allow the bolt 72 to pass therethrough and engage a washer 80 and nut 84. As the nut 84 is tightened, the bolt draws the facing strip 68 into contact with the plates 26 at an angle of about 45 degrees. The facing strip 26 covers the angle joint 64 and prevents splatter through the opening between the plates 26.
FIG. 5 shows a back view of the facing strip 34 and a plurality of brackets 38. Preferably, some of the brackets 38 are rotated 180 degrees from each other so that the openings 38a are on opposite sides of the brackets. This prevents the facing strip 34 from moving relative to the bolts 42 so that the bolts are pulled out of the brackets 38. Thus, the only way to remove the facing strip 34 once it is in place is to undo the nuts behind the washer 46 or backing plate.
Turning now to FIG. 6, there is shown a side view of the facing plate or strip 68 discussed with respect to FIG. 4. The facing strip 68 is attached to a plurality of bolts 72. This can be accomplished by welding the bolts 72 to the facing strip 68 or by providing a plurality of brackets, such as those shown on the facing strip 34 in FIG. 5. For the reasons discussed above, the brackets are preferred. However, because the facing strip 68 is not holding the plates 26 together, the welds on the bolts will generally last longer than those on a facing plate such as that shown in FIG. 1.
FIG. 6A shows a back view and FIG. 6B shows an end view of the facing strip 68 discussed with respect to FIGS. 4 and 6. It is important to note that the spacing of the bolts 72 is not critical to the functioning of the facing plate 68. However, the bolts 72 need to align with the openings 76 in the angle joint 64 (FIG. 4) to facilitate mounting of the facing plate 68.
Turning now to FIGS. 7 through 7B, there are shown two side views and an end view of angle joints 64 which have been modified to provide channels 76 for the bolts (not shown) of the facing plate (not shown). The angle joints 64 also have openings 90 formed therein which are used to secure bolts 92 (FIG. 4) which hold the angle joints 64 to the plates 26. The angle joints 64 are typically about 2.5 inches on each side, so that they provide adequate support without wasting material.
Thus there is disclosed an improved Joint for Bullet Traps. Those skilled in the art will appreciate numerous modifications which can be made without departing from the scope and spirit of the present invention. The appended claims are intended to cover such modifications.

## Claims

1. A ballistic joint, the joint comprising:
a first plate;
a second plate having an edge disposed adjacent an edge of the first plate;
a facing strip disposed to cover the adjacent edges of the first and second plates, the facing strip having a first end and a second end with lateral edges extending between the first end and second end, the facing strip being bent such that the facing strip contacts the first plate and the second plate only at the lateral edges of the facing strip, the facing strip having a front side and a back side and being disposed such that the front side faces away from the first plate and second plate and the back side faces towards the first plate and second plate;
at least one bracket, the at least one bracket having a first face and a second face generally parallel to the first face and defining a thickness therebetween, the at least one bracket having a width and length which are substantially greater than the thickness thereof, the at least one bracket having a slot formed therein, the slot extending through the at least one bracket in a direction perpendicular to the first face and second face and extending inwardly from an edge of the at least one bracket so as to be open to said edge, the at least one bracket being attached to the back side of the facing strip; and
at least one bolt for attaching the facing strip to the joint, the at least one bolt being disposed in the slot of the at least one bracket so as to be attached to the facing strip without penetrating through the facing strip.

2. The ballistic joint of claim 1, wherein the at least one bracket is flat and disposed generally parallel to the lateral edges of the facing strip.

3. The ballistic joint of claim 1, wherein the at least one bracket is welded to the facing strip.

4. The ballistic joint of claim 1, wherein the at least one bracket comprises at least two brackets attached to the back side of the facing strip, each having a slot formed therein through the thickness thereof for receiving a bolt, and wherein the slots on the at least two brackets are disposed on opposite side of the brackets from one another such that the slots are oriented in opposite directions.

5. The ballistic joint of claim 1, wherein the facing strip is bent along the center thereof to form an angle with flat sides extending outwardly and rearwardly to the first plate and the second plate.

6. The ballistic joint of claim 5, wherein the facing strip is bent to an angle of about 155 degrees.

7. The ballistic joint of claim 1, wherein the at least one bracket contacts the first and second plates.

8. The ballistic joint of claim 1, further comprising a backing means placed along the joint on the side of the first and second plates opposite the facing strip.

9. A bullet proof joint comprising:
a first bullet proof metal plate;
a second bullet proof metal plate having an edge thereof disposed adjacent an edge of the first bullet proof metal plate;
a facing strip configured to engage the first and second bullet proof plates along the adjacent edges thereof, the facing strip being bent along the center thereof such that only the edges of the facing strip which are parallel to the bend contact the bullet proof plates, the facing strip being bent at an angle less than 180 degrees, the facing strip having a front side disposed to face away from the first and second bullet proof plates such that the center of the facing strip extends away from the first and second bullet proof plates to a greater extent than the edges of the facing strip and the facing strip having a back side disposed towards the first and second bullet proof plates;
at least one bracket attached to the back side of the facing strip such that the bracket is positioned between the facing strip and the first and second bullet proof plates, the bracket having a thickness and having a length and a width greater than the thickness thereof, the bracket further having a slot formed through the thickness of the bracket and being open to an edge thereof so as to allow a shank of a bolt to be slid into the slot to thereby position the head of the bolt between the bracket and the facing strip; and
a bolt disposed in said slot so as to be attached to the facing strip without penetrating therethrough for holding the facing strip against the bullet proof plates.

10. The joint according to claim 9, wherein the at least one bracket is flat and disposed generally parallel to the edges of the facing strip.

11. The joint according to claim 9, wherein the at least one bracket is welded to the facing strip.

12. The joint according to claim 9, wherein the at least one bracket comprises a plurality of brackets having slots extending from edges thereof, and wherein at least two of the brackets having slots extending in opposite directions from one another.

13. The joint according to claim 9, wherein the facing strip is bent into an angle of about 155 degrees.

14. The joint of claim 9, wherein a head of the bolt is disposed between the facing strip and a bracket fixedly attached to the facing strip.

15. A method for forming a ballistic joint, the method comprising:
disposing first and second plates adjacent one another such that the plates have adjacent edges;
selecting a facing strip, the facing strip being bent lengthwise into an angle of about 155 degrees, the facing strip having a plurality of brackets attached to a back, concave side of the facing strip, each of the brackets having a slot formed through the thickness thereof and extending inwardly from an edge thereof, the slots being configured for allowing the shank of a bolt to slide into the slot in a direction transverse to the length of the bolt to thereby place the head of the bolt between the bracket and the facing strip, and wherein the plurality of brackets are configured for allowing a plurality of bolts to be removably attached to the facing strip while the brackets are attached to the facing strip such that the heads of the plurality of bolts are disposed between the plurality of brackets and the facing strip;
selecting a plurality of attachment bolts;
attaching the plurality of attachment bolts to the facing strip by placing the shanks of the plurality of bolts in the slots such that the heads of the plurality of bolts are located between the plurality of brackets and the facing strip such that the bolts do not penetrate the facing strip; and
placing the facing strip over the adjacent edges of the first and second plates generally parallel to the first and second plates so that the facing strip slopes rearwardly and outwardly such that the only portion of the facing strip brought into engagement with the first and second plates to secure the plates together is the lateral edges of the facing strip.

16. The method according to claim 15, wherein the method further comprises attaching the plurality of attachment bolts to the facing strip with brackets prior to the placement of the facing strip against the plates.

17. The method according to claim 16, wherein the method further comprises selecting a facing strip having a plurality of brackets which are flat and which are disposed generally parallel to the edges of the facing strip.

18. The method according to claim 16, wherein at least two of the brackets have slots for receiving the bolts which are disposed on opposing sides of the brackets.

19. The method of claim 15, wherein the method further comprises placing a backing means adjacent the opening on the side of the plates opposite the facing strip.

20. A method for forming a section of a bullet trap, the method comprising:
placing an edge of a first plate adjacent an edge of a second plate;
selecting a joint strip having a facing strip which is bent lengthwise, a bolt, and a bracket attached to the concave side of the facing strip for holding an end of the bolt to the facing strip, the bracket being attached to the facing strip independent of the bolt and having a slot formed through the thickness thereof and being open to an edge thereof so as to allow the shank of the bolt to be placed therein so as to place the head of the bolt between the bracket and the facing strip without removing the bracket from the facing strip;
placing the shank of the bolt in the slot such that the head of the bolt is between the bracket and the facing strip such that the bolt does not penetrate the facing strip;
covering the adjacent edges of the plates with the facing strip such that the bracket is disposed between the plates and the facing strip; and
engaging the lateral edges of the facing strip with the first and second plates so that the only portion of the facing strip which touches the first and second plates is the lateral edges.

21. The method according to claim 20, wherein the method further comprises placing a backing strip along the adjacent edges of the plates on the side of the plates opposite the joint strip.

22. The method according to claim 20, wherein the method further comprises selecting a joint strip having a plurality of brackets attached to the facing strip for holding a plurality of bolts.

23. The method according to claim 20, wherein the method further comprises selecting a facing strip which is bent lengthwise into an angle along the center thereof and having flat sides extending from the bend.

24. The method according to claim 20, wherein the method further comprises selecting a facing strip which is bent lengthwise into an angle of about 155 degrees.

25. The method according to claim 20, wherein the bracket is welded to the facing strip.

26. The method according to claim 20, wherein the bracket comprises a first bracket and a second bracket each having a slot extending inwardly from an edge thereof, and wherein the first bracket and second bracket are oriented such that the slots are oriented in different directions.

27. A ballistic joint comprising:
a first plate having an edge;
a second plate having an edge placed adjacent the edge of the first plate;
a facing strip disposed to cover the adjacent edges of the first plate and second plate, the facing strip having a front side which faces away from the first plate and second plate and a back side which faces towards the first plate and second plate;
a first bracket attached to the back side of the facing strip so as to be disposed between the facing strip and the first plate and second plate, the first bracket having a first slot extending through the thickness thereof and extending inwardly from an edge thereof; for receiving the shank of a bolt for attaching the facing strip to form the joint for covering the adjacent edges of the first and second plates
a second bracket attached to the back side of the facing strip so as to be disposed between the facing strip and the first plate and second plate, the second bracket having a second slot extending through the thickness thereof and extending inwardly from an edge thereof for receiving the shank of a bolt for attaching the facing strip to form the joint for covering the adjacent edges of the first and second plates, and
wherein the first bracket and second bracket are disposed such that the first slot and the second slot are oriented in different directions.

28. The ballistic joint of claim 27, further comprising a plurality of bolts for holding the facing strip against the first plate and second plate.

29. The ballistic joint of claim 28, wherein the bolts do not pass through the facing strip.

30. The ballistic joint of claim 28, wherein a shank of the bolts is releasably disposed in the slots of the first and second brackets.

31. The ballistic joint of claim 28, wherein a head of each of the plurality of bolts is disposed between a bracket and the facing strip.

32. The ballistic joint of claim 27, wherein the first bracket and second bracket are attached to the facing strip.

33. The ballistic joint of claim 27, wherein the slot of the first bracket and the slot of the second bracket extend in opposite directions.