U.S. patent application number 09/954628 was filed with the patent office on 2002-06-13 for granulate backstop assembly.
This patent application is currently assigned to Caswell International Corporation. Invention is credited to Faust, Paul T., Nesler, Leslie F., Wojcinski, Allan Stefan.
Application Number | 20020070502 09/954628 |
Document ID | / |
Family ID | 27498691 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020070502 |
Kind Code |
A1 |
Wojcinski, Allan Stefan ; et
al. |
June 13, 2002 |
Granulate backstop assembly
Abstract
The present disclosure relates to a projectile trap for
capturing projectiles emitted along a line substantially parallel
to an underlying ground/floor surface. The trap includes a support
structure including an inclined support surface that is inclined
relative to the line of the projectiles. The inclined support
surface includes a front edge positioned generally at the
ground/floor surface, and a rear edge oriented at a higher
elevation than the front edge. The trap also includes a particulate
flowable granular material supported by the support structure. At
least a portion of the granulate material is disposed above the
inclined support surface such that the inclined support surface is
substantially covered with granulate material. The granulate
material is adapted for slowing down and capturing the
projectiles.
Inventors: |
Wojcinski, Allan Stefan;
(Dusseldorf, DE) ; Nesler, Leslie F.; (St. Paul,
MN) ; Faust, Paul T.; (Edina, MN) |
Correspondence
Address: |
David G. Schmaltz
MERCHANT & GOULD P.C.
P.O. Box 2903
Minneapolis
MN
55402-0903
US
|
Assignee: |
Caswell International
Corporation
Minneapolis
MN
|
Family ID: |
27498691 |
Appl. No.: |
09/954628 |
Filed: |
September 17, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09954628 |
Sep 17, 2001 |
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09510571 |
Feb 22, 2000 |
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09510571 |
Feb 22, 2000 |
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09016128 |
Jan 30, 1997 |
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09016128 |
Jan 30, 1997 |
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08735473 |
Oct 23, 1996 |
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08735473 |
Oct 23, 1996 |
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08450821 |
May 25, 1995 |
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08450821 |
May 25, 1995 |
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08207855 |
Mar 8, 1994 |
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08207855 |
Mar 8, 1994 |
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07965749 |
Oct 23, 1992 |
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07965749 |
Oct 23, 1992 |
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07643539 |
Jan 18, 1991 |
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Current U.S.
Class: |
273/404 |
Current CPC
Class: |
F41J 13/00 20130101 |
Class at
Publication: |
273/404 |
International
Class: |
F41J 001/12 |
Claims
What is claimed is:
1. A projectile trap for capturing projectiles emitted along a line
substantially parallel to the ground, the trap comprising: a
support structure including an inclined support surface that is
inclined relative to the line of the projectiles; a particulate
flowable granular material supported by the support structure, at
least a portion of the granulate material being disposed above the
inclined support surface such that the inclined support surface is
substantially covered with granulate material, the granulate
material being adapted for slowing down and capturing the
projectiles; and a front retaining wall positioned in front of a
lower edge of the inclined support surface, the front retaining
wall extending across a front of the support structure and
extending in an upward direction from the ground, the front
retaining wall being arranged and configured to retain a portion of
the granulate material behind the retaining wall, and the retaining
wall having a height substantially shorter than a height of the
inclined support surface.
2. The projectile trap of claim 1, wherein the front retaining wall
is spaced from the lower edge of the inclined support surface such
that a desired thickness of granulate material is positioned
between the front retaining wall and the lower edge of the inclined
support surface.
3. The projectile trap of claim 2, further comprising a
self-healing member covering the granulate material.
4. The projectile trap of claim 3, wherein the self-healing member
extends in a generally upright direction and is positioned between
the inclined support surface and the front retaining wall.
5. The projectile trap of claim 4, further comprising side wall
portions extending between the self healing member and the front
retaining wall, wherein the self healing member, the side wall
portions and the front retaining wall cooperate to define a front
box-shaped cavity where granulate material will accumulate.
6. The projectile trap of claim 5, wherein the self healing member
defines holes for allowing granular material to flow into the
box-shaped cavity.
7. The projectile trap of claim 6, further comprising means for
vibrating the inclined support surface to encourage the granulate
material to flow through the holes into the box-shaped cavity.
8. The projectile trap of claim 1, further comprising a rear
retaining wall positioned at an upper edge of the inclined support
surface, the rear retaining wall extending across a back of the
support structure and extending in an upward direction from the
upper edge, and the front retaining wall being arranged and
configured to retain a portion of the granulate material in front
of the rear retaining wall.
9. The projectile trap of claim 8, wherein the front and rear
retaining walls are substantially parallel and substantially
upright.
10. The projectile trap of claim 1, wherein the granulate material
comprises particulate rubber, and the trap further includes an
anti-adhesion material interspersed between the particulate rubber,
whereby the anti-adhesion material prevents adhesion of the
particulate rubber in the presence of heat generated by the
received projectiles.
11. The projectile trap of claim 10, wherein the anti-adhesion
material comprises a powdered material which adheres to particulate
rubber material.
12. The projectile trap of claim 11, wherein the powdered material
comprises talc.
13. The projectile trap of claim 10, wherein the anti-adhesion
material comprises a powdered fire-retardant material which adheres
to the particulate rubber material.
14. The projectile trap of claim 13, wherein the powdered
fire-retardant material comprises a noncorrosive sodium bicarbonate
chemical.
15. The projectile trap of claim 1, wherein at least portions of
the support structure are made of steel.
16. The projectile trap of claim 1, wherein at least portions of
the support structure are made of concrete.
17. A projectile trap for capturing projectiles emitted along a
line substantially parallel to an underlying ground/floor surface,
the trap comprising: a support structure including an inclined
support surface that is inclined relative to the line of the
projectiles, the inclined support surface including a front edge
positioned generally at the ground/floor surface, and a rear edge
oriented at a higher elevation than the front edge; and a
particulate flowable granular material supported by the support
structure, at least a portion of the granulate material being
disposed above the inclined support surface such that the inclined
support surface is substantially covered with granulate material,
the granulate material being adapted for slowing down and capturing
the projectiles.
18. The projectile trap of claim 17, wherein the granulate material
comprises particulate rubber, and the trap further includes a
fire-retardant material interspersed between the particulate
rubber.
19. The projectile trap of claim 17, wherein at least portions of
the support structure are made of steel.
20. The projectile trap of claim 17, wherein at least portions of
the support structure are made of concrete.
21. The projectile trap of claim 17, further comprising a
self-healing member that covers the granulate material, whereby the
projectiles penetrate the self-healing member in order to enter the
particulate granulate material.
Description
CROSS REFERENCE TO PARENT APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 08/735,473 filed on Oct. 23, 1996, which is a
continuation-in-part of U.S. application Ser. No. 08/450,821, which
was filed on May 25, 1995, and issued as U.S. Pat. No. 5,607,163 on
Mar. 4, 1997, which is a continuation-in-part of U.S. patent
application Ser. No. 08/207,855, which was filed on Mar. 8, 1994
and issued as U.S. Pat. No. 5,435,571 on Jul. 25, 1995, which is a
continuation-in-part of U.S. patent application Ser. No.
07/965,749, filed Oct. 23, 1992, which was issued as U.S. Pat. No.
5,340,117 on Aug. 23, 1994 and is a continuation of U.S. patent
application Ser. No. 07/643,539, filed Jan. 18, 1991, which was
issued as U.S. Pat. No. 5,171,020 on Dec. 15, 1992.
FIELD OF THE INVENTION
[0002] The present invention generally relates to range safety
devices, and more specifically to a projectile backstop assembly
using granulate material.
BACKGROUND OF THE INVENTION
[0003] A number of backstop assemblies have been known whose object
is to slow down projectiles fired into them along a specified
distance until they drop to the ground. For example, German Patent
31 31 228 discloses a backstop assembly in which multiple panels
are vertically spaced from each other in two rows so that zigzag
passages are formed between the panels of the rows where
projectiles are bounced back and forth until they have slowed down
enough to drop to the ground. DE-OS 32 12 781 discloses another
backstop assembly wherein a container holds a granulate bonded by a
bonding agent into a lumped structure, of which the objective also
is to slow down projectiles fired into the granulate.
[0004] One drawback of the prior granulate-type backstop assembly
is that it is difficult to dispose since the projectiles fired into
the bonded granulate are retained thereby, i.e. they become part of
the bonded granulate. As a consequence, removal of the projectiles
is possible only by disposing the bonded granulate together with
the projectiles embedded therein. Thus the quantities to be
disposed of per unit backstop operating time are relatively high.
Further, a major effort and considerable expense are needed to
separate the bonded granulate from the projectiles embedded
therein.
[0005] Therefore, there is a need for an improved backstop assembly
of the kind specified above so that projectiles may be disposed in
a simpler and more efficient manner.
SUMMARY OF THE INVENTION
[0006] The present invention provides a granulate backstop assembly
that allows simple disposal of projectiles. In particular, the
granulate may be separated in a simple and efficient manner from
the slowed-down projectiles included therein. As a consequence, the
projectiles or projectile fragments may be recovered very simply
and reconditioned and further processed. At the same time the
granulate so reconditioned may be re-used in the backstop assembly.
The overall operating costs of the inventive backstop assembly are
greatly reduced since the granulate used as a slowing-down medium
may be re-used and the quantities ultimately to be disposed of,
i.e. the projectiles removed from the backstop assembly, are much
smaller. Further, the inventive backstop assembly does not involve
the outages needed in prior assemblies to replace the slowing-down
media (rubber louvers or bonded granulate) used therein.
[0007] One embodiment of the present invention is a backstop
assembly including a container having a plurality sides, at least
two of the sides defining target openings for allowing projectiles
such as bullets to enter the container. The target openings are
enclosed by a plurality of self-healing sheets such that the
projectiles penetrate the self-healing sheets in order to enter the
container. A particulate material is contained within the container
for slowing down and capturing the projectiles within the
container. The backstop assembly also includes a structure for
facilitating movement of the backstop assembly such that the
backstop assembly can be easily reoriented to expose different
sides to projectile fire.
[0008] Another embodiment of the present invention is a backstop
assembly including a container having an opening covered by a
self-healing medium for allowing projectiles to enter the
container. The container includes first and second chambers which
are filled with particulate material for slowing down and capturing
the projectiles within the container. The first and second chambers
are separated such that particulate material and spent projectiles
can be removed from the first chamber without removing the
particulate material and spent projectiles within the second
chamber thereby improving the cost effectiveness of the backstop
assembly.
[0009] Yet another embodiment of the present invention is a
projectile trap assembly for capturing projectiles emitted along a
line substantially parallel to ground. The projectile trap assembly
includes a support frame having an upper surface inclined relative
to the line of the projectiles and a particulate flowable granulate
material exhibiting an angle of repose. The particulate granulate
material is supported by the support frame at the angle of repose,
whereby the particulate granulate material receives and slows down
the projectiles.
[0010] A variety of advantages of the invention will be set forth
in part in the description which follows, and in part will be
obvious from the description, or may be learned by practice of the
invention. The advantages of the invention will be realized and
attained by means of the elements and combinations particularly
pointed out in the claims. It is to be understood that both the
foregoing general description and the following detailed
description are exemplary and explanatory only and are not
restrictive of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate several
embodiments of the invention and together with the description,
serve to explain the principles of the invention. A brief
description of the drawings is as follows:
[0012] FIG. 1 shows a schematic view partly in section of the
structure of the preferred embodiment of the inventive backstop
assembly;
[0013] FIG. 2 shows a side view of the container of the preferred
backstop assembly of FIG. 1;
[0014] FIG. 3 shows one special form of the container in the
inventive backstop assembly;
[0015] FIG. 4 shows another special form of the container in the
inventive backstop assembly;
[0016] FIG. 5 shows a backstop assembly with a large backstop
surface;
[0017] FIG. 6 shows a side view of a backstop assembly with a
rotatable container;
[0018] FIG. 7 shows a front view of the backstop assembly of FIG.
6;
[0019] FIG. 8 shows a backstop assembly with an agitating mechanism
for the granulate location in the container;
[0020] FIG. 9A shows a cross-sectional view of the embodiment of
FIG. 8;
[0021] FIG. 9B shows an exploded view of a detail of FIG. 9A;
[0022] FIG. 10 shows another cross-sectional view of the embodiment
of FIG. 8;
[0023] FIG. 11 shows another embodiment of the container for the
inventive backstop assembly related in form to that shown in FIG. 4
and using a chain assembly to agitate the granulate;
[0024] FIG. 12 shows a cross-sectional view of the embodiment of
FIG. 11;
[0025] FIG. 13 shows another cross-sectional view of the embodiment
of FIG. 11;
[0026] FIG. 14 shows a further embodiment of the container for the
inventive backstop assembly, related to that shown in FIG. 9A;
[0027] FIG. 15 shows details of the projectile entry openings for
the embodiment of FIG. 14;
[0028] FIG. 16 shows yet another embodiment of the container for
the inventive backstop assembly, related to that shown in FIGS. 6
and 7;
[0029] FIG. 17 shows details of an angled rotary union used in the
container of FIG. 16;
[0030] FIG. 18 shows an embodiment of the container for the
inventive backstop assembly having a liquid cooling system;
[0031] FIG. 19 shows an embodiment of the container for the
inventive backstop assembly having a granulate circulation
screw;
[0032] FIG. 20 shows a side view of a moveable backstop assembly
constructed in accordance with the principles of the present
invention;
[0033] FIG. 21 shows another side view of the backstop assembly of
FIG. 20;
[0034] FIG. 22 shows a bottom view of the backstop assembly of FIG.
20;
[0035] FIG. 23 shows a side view of the backstop assembly of FIG.
20 including a vacuum assembly;
[0036] FIG. 24 shows a side view of another backstop assembly
constructed in accordance with the principles of the present
invention;
[0037] FIG. 25 shows a side view of a exemplary projectile trap
assembly having an inclined supporting surface according to the
principles of the present invention; and
[0038] FIG. 26 shows a side view of another exemplary projectile
trap assembly according to the principles of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0039] Reference will now be made in detail to exemplary
embodiments of the present invention which are illustrated in the
accompanying drawings. Wherever possible, the same reference
numbers will be used throughout the drawings to refer to the same
or like parts.
[0040] As shown in FIG. 1, the present granulate backstop assembly
substantially comprises a preferably box-like container 1 having on
one side, which is located behind a target surface, an opening 11
closed by a preferably disk-like medium 2 through which the
projectiles fired towards the target area may pass. Medium 2
preferably comprises a rubber sheet. Because of the rubber
material's inherent elasticity, the holes formed in rubber sheet 2
as the projectiles penetrate it close automatically when the
projectiles have passed completely through sheet 2. Rubber sheet 2
is preferably mounted in front of opening 11 in such a manner that
it closes opening 11 like a wall panel. It will be recognized that
other well-known self-healing sheets, for example polymer sheets,
may be substituted for the rubber sheet without loss of
generality.
[0041] Container 1 has therein a granulate 3, which generally
comprises a particulate flowable soft material capable of slowing
down the projectiles fired into container 1 through rubber sheet 2,
such slowing-down taking place along length L (FIG. 2) of container
1. Granulate 3 preferably consists of a particulate rubber material
having an exemplary particle size of approx. 6 mm; a material of
this kind is commercially available as a waste product.
[0042] In the operation of the present backstop assembly, the
projectiles fired towards the target area disposed in front of
rubber sheet 2 penetrate the latter. On the way along distance L of
container 1, granulate 3 slows the projectiles down. For disposing
of the contents of container 1 after some time, it is necessary
merely to discharge granulate 3 and the projectiles and projectile
fragments therein and to fill container 1 with fresh granulate 3.
To this end, container 1 may have a discharge opening such as the
pipe-shaped opening 4 shown in FIG. 4 and a fill opening (not
shown) e.g. in the top container wall. The projectiles and
projectile fragments contained in the discharged granulate may be
removed from the latter in a simple known-per-se manner, as will be
described in greater detail below.
[0043] FIGS. 1-4 show preferred embodiments of the container. As
shown in FIG. 3, the container is box-like in shape, with rubber
sheet 2 forming the front wall of container 1' and closing opening
11' defined by the sidewalls, the top wall and the bottom wall. On
its side opposite rubber sheet 2, the container is sealed by a rear
wall. The bottom wall of the container starts at the bottom end of
the rear wall and slopes downwardly towards rubber sheet 2 so that
the lower-most point of the container lies about where the bottom
wall meets rubber sheet 2. A granulate discharge opening 4' is
located in that same area. The container of FIG. 4 is similar in
construction to that of FIG. 3--apart from the fact that the bottom
wall starts at rubber sheet 2 and slopes downwardly towards the
rear wall so that the lowest point of container 1" lies about where
the rear wall meets the bottom wall. Preferably, a discharge
opening 4" is located in that area. Container 1 of FIGS. 1 and 2 is
box-like in shape as well, with the bottom wall of container 1
having a tapered hopper shape, with the top opening of the hopper
being attached to the container walls; the bottom end of the
container forms discharge opening 4. Discharge opening 4, 4', 4"
preferably is formed by a short length of pipe attached to
container 1, 1', 1" and is sealable by means of a cover or the
like.
[0044] It should be noted that rubber sheet 2 of container 1, 1',
1" may be disposed behind a target surface or may itself form that
target surface. To this end, rubber sheet 2 may be externally
coated with a white material to serve as a projection screen for
stationary or moving target images generated by means of a suitable
projector. In the simplest case, the fired-upon granulate is
disposed of in any way desired at a location separate from the
backstop after having been discharged from container 1, 1', 1".
[0045] In a preferred embodiment of the present backstop assembly,
the aforesaid disposal is performed automatically as shown in FIG.
1. To this end, discharge opening 4 is connected through a valve 5
with input 6 of separating means 7 having a first output connected
to line 9 and a second output 8. In separating means 7, the
particulate granulate 3 is separated from projectile fragments,
with the latter being passed on to output 8 and the granulate being
recycled to container through return line 9 and an opening 10 in a
container wall.
[0046] Advantageously, separating means 7 sucks off the granulate
and the projectile fragments from container 1 through opened valve
5, with separating means 7 further utilizing the difference in
weight of granulate 3 and the projectile fragments to so separate
them that the relatively heavier projectile fragments are passed on
to output 8 and the relatively lighter granulate particles are
passed on to return line 9. For example, separating means 7 may
comprise a known-per-se centrifugal separator or a vacuum separator
in which the particles and fragments attracted by a created vacuum
are separated in such a manner that the heavier particles are
passed on to output 8 and the vacuum causes the lighter particles
to be drawn back to container 1 through line 9. The necessary
vacuum pump may be located inside separating means 7 itself, at
opening 10 in return line 9 inside the container 1 or within return
line 9 itself. It is contemplated also to return the granulate
particles separating means 7 has separated from the projectile
fragments to container 1 via return line 9 by positive
pressure.
[0047] Separation inside separating means may also be effected by
the jet from a blower which carries light particles towards return
line 9 and allows heavy particles to move to output 8. It is
contemplated in this context to use sensors which control the jet
in dependence on the nature of the particles they sense (granulate
or projectiles or projectile fragments).
[0048] FIG. 5 shows a further development of the invention in which
a large projectile backstop area, which may have dimensions of 4 m
by 8 m, for example, is formed by a container 1'" of which the
projectile entry opening 11'" corresponds to the size of the
projectile backstop area. Along width B of container 1'", several
spaced granulate discharge sites are provided, which may be formed
by a plurality of hopper-like sections arranged and interconnected
side by side. Each discharge site is connected through a valve 41,
42, 43 with a collecting line 9" for the discharged granulate
containing projectiles and projectile fragments. Collecting line 9'
is connected with separating means 7' having an output 8' for
projectiles and projectile fragments and an additional output
connected with a return line 9' run into the interior of container
1'". Since a rubber sheet covering all of the large-size opening
11'" is relatively expensive, opening 11'" is preferably sealed by
a plurality of rubber sheets 2' placed side by side to abut at
their edges or overlap in the manner shown.
[0049] The disposal scheme used for this kind of backstop assembly
may advantageously be designed to take into account the extent to
which the sections thereof are used for target practice within a
given operating period since valves 41, 42, 43 may be opened
separately in dependence on the projectile (fragment) load the
associated sections of granulate 3 experience.
[0050] It is pointed out that the walls of container 1, 1', 1", 1'"
preferably consist of steel. It is contemplated that at least
portions thereof may be concrete walls, as may exist where the
assembly is to be installed.
[0051] FIGS. 6 and 7 show a further development of the invention in
which container 50 of the backstop assembly is adapted to have
motion imparted thereto by means 51 in such a manner that motion is
imparted also to contents of container 50, i.e. to the fired-upon
granulate, so as to prevent it from lumping and to ensure that the
projectiles fired into the granulate are moved from the main impact
area so that newly entering projectiles cannot strike projectiles
previously brought to rest by the granulate.
[0052] In the embodiment shown in FIGS. 6 and 7, means 51 is
constructed to rotate container 50 about its longitudinal axis 54.
These rotations keep granulate 51' from lumping; also, projectiles
and projectile fragments in granulate 51' are transported away from
the impact area behind entry opening 52. Entry opening 52 is sealed
by a medium 53 projectiles are capable of penetrating, such as
rubber sheeting.
[0053] Preferably, container 50 is rotated about its longitudinal
axis 54 by being rotatably mounted in a frame preferably formed of
a base plate 55 and a plurality of uprights 56', 56" extending
vertically upwards from the base. In particular, two spaced
uprights 56" are provided on one side of base plate 55 and each
have at their free end a roll 57 mounted for rotation about an axis
57'. Rolls 57 roll on a race 58 within which container 50 is
mounted preferably by race 58 being firmly connected to container
50, which is square in shape, at the four outer edges thereof (see
FIG. 7). Container 50 is rotated by a drive motor 57 mounted on
base plate 55 or on an upright 56 mounted along the opposite side
of base plate 55, the driving power being transmitted by a toothed
belt 58 trained around a pinion 59 of drive motor 57 and a driven
gear 60 of container 50 to rotate the latter. Driven gear 60 is
secured on a drive shaft 61 coaxial with longitudinal axis 54 of
container 50 for joint rotation therewith. Drive shaft 51 is
jounalled in a bearing assembly 62 mounted on upright 56'.
[0054] To lock container 50 in a given position, race 58 preferably
has at one end an outwardly directed annular flange 63 having an
opening 64 therein to lockingly receive a bolt 65 which may be
provided on a hinged plate 66 of which the end opposite bolt 65 is
rotatable about an axis 67 transverse of the longitudinal extent of
bolt 65. What this means is that the plate having locking bolt 65
thereon may be rotated between positions in which bolt 65 lockingly
engages or does not engage opening 64, respectively.
[0055] In the manner described and shown, container 50 may be
formed on one side with an outwardly directed bulge 68 which
enables the interior of container 50 to be filled with granulate to
a level higher than the container wall 69 from which it extends.
This way, the entire area behind projectile entry opening 52 may
effectively be filled with granulate. Container 50 may have in a
wall thereof--e.g. in the area of the aforesaid bulged portion
68--a cover wall 69 to be attached to the container body by means
of threaded fasteners; this cover enables container 50 to be opened
for removing spent granulate therefrom and for filling fresh
granulate into it. For example, container 50 may be emptied by
rotating it into a position in which said cover wall 69 is in its
lowermost position.
[0056] It is contemplated also to use instead of the container 50
shown, which is rectangular in shape, containers which have a
circular cross section in at least portions of the periphery
thereof so that the circular portion may be seated directly on
rolls 57, obviating race 58.
[0057] For example, container 50 may be rotated with a speed of
approximately 2 r.p.m., causing any lumps in the granulate to
dissolve and projectiles or projectile particles in the granulate
to be moved towards the inner container walls, thus keeping the
projectile entry area clear of projectiles or projectile
particles.
[0058] Plate 66, which preferably is part of a hinge assembly, is
preferably mounted for rotation about axis 67 on a transverse
member 56" extending between uprights 56. It is contemplated also
to provide spaced rolls similar to rolls 57, 57 on each side of
container 50 and mounted on the frame, with at least one of such
rolls being adapted to be driven for rotating container 50. In a
design of this kind, the container may have two races (similar to
race 58); alternatively, the container may have a circular cross
section in the area of each pair of rolls.
[0059] Another embodiment of the invention will now be explained
under reference to FIGS. 8 to 10. In this embodiment, a container
70 is similar in construction to the container explained above in
connection with FIG. 4.
[0060] Provided inside this container in front of rear wall 65 is
an agitating mechanism 72 comprising a screw 75. Screw 75 is
located in a housing 77 having an opening 78 in its bottom portion.
Granulate may be fed through this opening 78 to the area in which
screw 75 operates in the bottom region of housing 70. Suitably
rotated, screw 75 moves the granulate previously introduced through
opening 78 into housing 77 upwardly in the direction of arrow 75'
and is discharged at the top end of housing 77 of agitating
mechanism 72 in the direction of arrows 79 through openings 80 so
as to create a steady flow of granulate.
[0061] The rubber sheet overlying the projectile entry opening is
shown at 70'".
[0062] In the manner shown in FIG. 8, a drive motor 73 rotates
screw 75 through a gear box 74. Drive motor is preferably mounted
on top wall 70' of container 70.
[0063] Extension tubes 80' may be attached at openings 80, as shown
schematically in phantom in FIG. 8 so that the granulate is
discharged at locations radially spaced from the axis of screw
75.
[0064] In order to get the projectiles or projectile fragments in
the granulate to move towards bottom wall 70", vibrating means 81
may be provided as shown in FIG. 9. Vibrating means 81 imparts
vibrations to bottom wall 70" which are transmitted to the
granulate in container 70 and the projectile particles therein.
Since the projectiles and projectile particles are heavier than the
granulate particles, the former are moved downwards at a greater
rate than the granulate so that they will accumulate in the region
of bottom wall 70". Bottom wall 70" is sloped so that the
projectiles and projectile fragments will accumulate at the
lowermost point of bottom plate 70".
[0065] Vibrating means 81 is shown schematically in FIG. 9.
Exemplary components thereof are a drive assembly 82 which imparts
vibrations to a vibrator panel 83 preferably through eccentric
means (not shown) included in drive assembly 82. Flexible edge bars
84 are used preferably to mount vibrator plate 83 on bottom panel
70" in such a manner that the former can vibrate relative to the
latter, such vibrations being received by the flexible edge bars 84
which consist of rubber enclose the marginal area of vibration
panel 83 in a C-shaped configuration, for example. One side of the
C-shaped edge bars is attached to bottom plate 70".
[0066] Another embodiment of the invention will now be explained
under reference to FIGS. 11 to 13. In this embodiment, a container
90 preferably in the form explained above under reference to FIG. 4
and having a projectile entry opening 91 covered up e.g. by a
rubber sheet 92, an endless chain assembly 93 is provided to impart
motion to the granulate. Said endless chain assembly 93 essentially
comprises four rolls 94, 95, 96 and 97 spaced in front of rear wall
93" of container 93 in such a way as to lie approximately behind
corners of projectile entry opening 91. The roll assemblies are
conveniently mounted on rear wall 93".
[0067] In the example shown, each roll assembly 94 to 97 has in the
manner specifically shown in FIG. 11 two spaced rolls 99, 100
mounted on one shaft 98. Rolls 99, 100 comprise sprockets around
which chains 101 are trained. Since roll assemblies 94 to 95 are
located approximately in the corners of projectile entry opening
91, the chains do not run through the main projectile entry region
and cannot be damaged during operation of the inventive projectile
backstop assembly. Roll assemblies 94 are preferably protected by
steel sheet guard members 102 provided in front of them, seen in
the shooting direction (see FIG. 1 specifically).
[0068] One of shafts 98 is selectively rotated by drive means;
sprockets 99, 100 on that shaft (FIG. 11, top right-hand corner)
are firmly attached thereto for joint rotation.
[0069] Spaced endless chains 101, 101 are interconnected preferably
in regular intervals by transverse members 103, which in the manner
shown in FIG. 12 may have the shape of angled entrainment members.
As the chains are circulated in a clockwise direction, the movement
of chains 101, 101 and of transverse members 103 along the inner
surfaces of the sidewalls, the bottom wall and the top wall of
container 90 causes the granulate in the regions of the aforesaid
walls of container 90 to be moved (arrows 104). In addition to this
peripheral movement, the granulate particles move under gravity
from the top to the bottom approximately in the direction of arrows
105 so that the projectiles and/or projectile particles contained
in the granulate are moved from the top to the bottom towards
bottom wall 93'" to accumulate thereat.
[0070] In the manner shown in FIG. 13, guard plates 102 may be
angled to form ramps along which impinging projectiles may slide
away from roll assemblies 94 to 97 into the interior regions of
container 90, thus affording protection of the aforesaid roll
assemblies.
[0071] It is to be noted that--instead of dual-chain assembly 93--a
corresponding single-chain assembly may be used which has
projecting transverse entrainment members or the like.
[0072] In the following, another further development will be
explained under reference to FIGS. 14 and 15 in which container 130
has at its bottom wall 130' the vibrating means previously
discussed under reference to FIG. 9. Details of this vibrating
means previously explained under reference to FIG. 9 will therefore
be identified by like numerals. Lower wall 130' of container 130 is
sloped--preferably in a manner that lowermost point 130" of
container 130 lies at the front thereof, i.e. on its projectile
entry side. As previously explained, the projectile entry opening
of container 130 is sealed by a medium 132 preferably in the form
of at least one rubber panel through which projectiles can travel
and enter container 130. In the manner shown in FIG. 15, and as
previously explained under reference to FIG. 12, the projectile
entry opening can be formed by a plurality of laterally overlapping
media or rubber sheets 132. In the lower marginal region, the at
least one rubber sheet 132 of the overlapping multiple rubber
sheets 132 have spaced openings 133 through which granulate 3 can
enter from container 130 into region 134" in front of openings 133
when vibrating means 81 is operated. Openings 133 have in front of
them wall 134 (FIG. 14) spaced from and preferably extending
parallel to rubber sheet(s) 132 on the side opposite container 130.
The height of wall 134 is selected so as to at least cover up
openings 133. Between the sidewalls of container 130 and wall 134
extend sidewall portions 134' (FIG. 14) which together with wall
134 and the lower portions of rubber sheets 132 and a bottom wall
portion 134'" form a box-shaped cavity 134" where granulate 3 will
accumulate to a predetermined level when vibrating means 81
operates. Once the backstop assembly has been fired at, granulate 3
in cavity 134" has projectiles and/or projectile particles
dispersed therethrough.
[0073] Wall 134 is preferably made of a material which can be
penetrated by the projectiles fired at the backstop assembly. One
advantage of that wall is that it forms together with granulate 3
in cavity 134" therebehind a protection for the lower steel
structure (lower wall 130', frame members, etc.) since projectiles
penetrating wall 134 will be slowed down in cavity 134" before they
reach any steel structural element, and this to the point that they
cannot exit from cavity 134" any longer after they have struck a
said steel structural element.
[0074] The granulate 3 in cavity 134", which has projectile
fragments and/or projectiles therein, may be cleaned by the vacuum
discharge and separating means previously discussed under reference
to FIGS. 1 and 5. More specifically, granulate 3 and the projectile
fragments therein may be sucked from cavity 134" and passed on to
separating means 155 where the projectile fragments are separated
from granulate 3. Following the separating means, the cleaned
granulate may be recycled to container 130 through line 156 and
preferably through the top wall thereof. It is sufficient to
operate vibrating means 81 and to discharge granulate 3 from cavity
134" for the removal of projectile fragments after a predetermined
operating period such as several times a day if the backstop
assembly is intensively used. In the manner described above, the
projectile-loaded granulate may be removed from cavity 134" after
predetermined operating periods and suitably disposed at a site
remote from container 130.
[0075] There will now be explained under reference to FIG. 16
another further development of the embodiment shown in FIGS. 6 and
7, which development is suited specifically for backstopping tracer
ammunition projectiles. Details of FIG. 16 previously explained
under reference to FIGS. 6 and 7 are identified by like reference
numerals. As tracer projectiles penetrate medium 53 and enter
container 50, they may cause the particles of granulate 3 to lump
or fuse. To counteract this tendency, container 50 has supplied
thereto--preferably through an angled rotary union--a quenching
fluid such as water. More specifically, drive shaft 61 has an inner
bore 61' through which the fluid is introduced in the direction of
arrow 140. On its free end, shaft 61 has an angled rotary union 141
attached thereto which communicates rotating drive shaft 61 with a
supply line 142 to pipe the liquid to the point of use. Angled
rotary unions of this kind are known; for example, they may be
attached to rotating drive shaft 61 by means of a coupling or union
nut 143 in the manner shown in FIG. 17. Union nut 143 is held on a
tube 144 for rotation in a fluid-tight seal. Tube 144 communicates
with supply line 142 through an opening 145.
[0076] For collecting quenching fluid escaping from container 50, a
collecting vessel 150 may be provided where shown in phantom in
FIG. 16; conveniently, this vessel has the form of a pan or trough
150 placed underneath container 50 particularly to catch the liquid
dripping from leaks caused in medium 53 by the projectiles passing
therethrough. A pump 151 and a return line 152 may be used to
remove that fluid from pan 150 for return to container 50 through
supply line 142. Pump 151 preferably has a reservoir so that, when
the latter is full, the fluid may be discharged into container 50
through supply line 142 and bore 61'.
[0077] High velocity projectiles or tracer projectiles may produce
a large amount of heat within the granulate material, causing the
individual granulate particles to adhere to each other. The
adhesion of these particles reduces the effectiveness of the
granulate as a backstop medium.
[0078] Adhesion of the granulate particles is overcome by
interspersing a particulate matter such as talc between the
granulate particles. The talc adheres to the outside surface of the
particles and prevents adhesion, especially in the presence of heat
generated by entering projectiles. Talc is a preferred particulate
matter because it is cheap, readily available, and is non-volatile
in the presence of heat. However, it will be recognized that other
particulate matter with similar lubrication characteristics as talc
may be substituted without loss of generality.
[0079] Heat generated within the granulate material by entering
projectiles or tracer rounds is reduced by the preferred backstop
apparatus of FIG. 18. A pump 184 is used to pump a liquid coolant
such as water from reservoir 183 up through pipe 185 where the
liquid coolant is dispersed at 186 above the granulate material.
The liquid coolant flows downward through the granulate by
gravitational action, contacting the bottom wall 130 and collecting
at opening 181. The liquid coolant returns to reservoir 183 via
return channel 182. It will be recognized that non-volatile liquid
coolants other than water may be substituted without loss of
generality. It will also be recognized that it is possible to
combine the use of a particulate matter such as talc with the
liquid coolant such as water in order to have the combined effect
of preventing adhesion of the granulate particles and reducing heat
within the backstop assembly.
[0080] A particulate matter may also be interspersed between the
granulate particles to cause the granulate to be self-extinguishing
or fire-retardant in the presence of heat generated by entering
high-velocity projectiles or incendiary projectiles. A preferred
self-extinguishing particulate matter is a noncorrosive sodium
bicarbonate based chemical as commonly found in fire extinguishers.
However, it will be recognized that other particulate matter with
similar self-extinguishing characteristics as noncorrosive sodium
bicarbonate may be substituted without loss of generality. The
self-extinguishing particulate matter be may used either with or
without the lubricating particulate matter or liquid. It will be
recognized that a lubrication property and a self-extinguishing
property may be contained together in the same particulate matter
or liquid. It will be further recognized that a self-extinguishing
material, not necessarily based on a noncorrosive sodium
bicarbonate chemical, may also be annealed to, coated, permeated
within, or otherwise provided as the outside surface of the
granulate particles according to well-known manufacturing
techniques to achieve the same self-extinguishing or fire retardant
characteristics as a particulate matter interspersed between the
granulate particles.
[0081] Once the granulate has been lubricated to reduce adhesion of
the particles, entering projectiles cause previously trapped
projectiles to move further downward through the lubricated
granulate. Entering projectiles cause cavitation within the
granulate, thereby creating voids which cause the previously
entrapped projectiles to move downward from the place at which they
were originally resting prior to the entrance of other
projectiles.
[0082] The preferred system for keeping the granulate behind the
bull's eye free of projectiles, recycling the granulate, and
removing the projectiles is shown in FIG. 19. A motor 191 drives a
granulate circulation screw 192 to move the entire mass of
granulate downward in the main chamber towards the discharge
opening 133. Periodically, the system is activated to agitate the
granulate in the main chamber to cause it to flow toward the
discharge opening 133 while the granulate is removed from the base
holding area 134 by conveyor, vacuum device, or other means 155
which lifts and deposits only the granulate back into the top of
the main chamber. The projectiles are screened from the granulate
by screen 193 and remain in the projectile holding area 194. The
entire mass of granulate and projectiles moves toward the main
chamber discharge opening 133, and the cleaned granulate is
deposited at the main chamber top opening to replenish the
granulate level. Projectiles may be separated and captured during
this process through screening, centrifuge, or by other separation
means. Preferably, cleansing and recycling of the granulate is done
more often than the removal of the projectiles. Projectile
separation from the granulate and removal from the trap is
accomplished by blocking the flow of material from the main chamber
discharge opening 133. The granulate in the projectile holding area
134 is then vacuumed or otherwise removed and deposited back into
the main chamber top opening or into the base holding area or into
both areas. The vacuum device is incapable of lifting the heavier
projectiles and they remain in the hold area for removal with a
scoop or shovel. It will be recognized that the same separation
principle also applies to conveyors or other deliverance means
other than vacuum means or circulation screw, and that the
projectiles may be screened by screen 193 and collected in the
projectile holding area 194. The circulation system may preferably
be turned on again to allow the main chamber granulate material to
flow into and fill the base holding area. Again the main chamber
discharge opening 133 is preferably blocked and the process
repeated. If necessary, clean granulate is preferably added to the
main chamber to maintain the correct level.
[0083] Entrapped projectiles may be further encouraged to move
downward through the granulate by means of agitation induced by
either fixed or portable vibrating means applied to the front,
back, bottom, or sides of the enclosure. The portable vibrating
means allows an operator to selectively agitate a portion of the
enclosure, typically where the concentration of entrapped
projectiles is expected to be the highest. The portable vibrating
means may further comprise an extension which may be lowered at any
level into the enclosure from above to directly agitate selected
areas of the granulate within the enclosure.
[0084] FIGS. 20-23 illustrate another backstop assembly 200 which
is an embodiment of the present invention. The backstop assembly
200 includes a box-like container 202 having first, second, third
and fourth target openings 204, 206, 208, 210 defined by the sides
of the container for allowing projectiles to enter the container
202. The target openings 204, 206, 208, 210 are covered by
self-healing sheets 212 which enclose the sides of the container
202. The self-healing sheets 212 are penetrated by the projectiles
when the projectiles enter the container 202. Held within the
container 202 is soft particulate material 214 for slowing down and
capturing the projectiles within the container 202. The backstop
assembly 200 also includes a structure for facilitating movement of
the backstop assembly 200 such as wheels 216 which are connected to
the container 202.
[0085] Structural support for the box-like container 202 is
preferably provided by a welded steel framework 218 which defines
the outer edges of the container 202. The framework of the
container 202 defines opposing first and second trapezoid shaped
sides 220, 222 which respectively define the first and second
target openings 204, 206. The framework 218 of the container 202
also defines opposing first and second rectangle shaped sides 224,
226 which respectively define the third and fourth target openings
208, 210.
[0086] As described above, the sides of the container 220, 222,
224, 226 are enclosed by the self-healing sheets 212. The
self-healing sheets 212 is connected to the framework 218 by
conventional fastening methods such as screws or bolts which are
arranged about the perimeters of the sheets 212 and engage the
framework 218. The sheets 212 effectively cover the target openings
204, 206, 208, 210 such that the particulate material 214 is held
within the container 202. Additionally, the framework 218 of the
container is preferably covered with an extra layer 227 of rubber
sheet, located between the framework 218 and the self-healing
sheets 212, for preventing projectiles from ricocheting off the
framework 218.
[0087] The container 202 preferably includes a base plate 228 which
is welded to the framework 218 at the bottom of the container 202
and supports the particulate material 214 within the container 202.
The base plate 228 is inclined and has an upper edge 230 and a
lower edge 232. The lower edge 232 is positioned adjacent to a
rectangular discharge opening 234 defined by the second rectangular
side 226 and located below the fourth target opening 210. Because
the discharge opening 234 is located adjacent to the lower edge 232
of the base plate 228, the discharge opening 234 facilitates
removal of the particulate material 214 and captured projectiles
from the container 202. It will be appreciated that when the
backstop assembly 200 is in use, the discharge opening 234 is
preferably covered by steel shutters 236 which prevents the
particulate material 214 from escaping from the container 202.
[0088] The backstop assembly 200 further includes a removable top
panel 238 which encloses the top of the container 202 to prevent
the particulate material 214 from escaping while the backstop
assembly 200 is in use. The top panel 238 is supported by a pair of
support members 240 which are connected to the framework 218
adjacent the top of the container 202. The support members 240 are
arranged generally in the shape of a cross and provide support for
the top panel 238 which rests upon the support members 240.
[0089] The backstop assembly 200 also preferably includes four legs
242 which are preferably connected to the framework 218 adjacent
the bottom of the container 202. The legs 242 extend vertically
downward from the container 202 and serve the purpose of elevating
the container 202.
[0090] The wheels 216 of the backstop assembly 200 are preferably
connected to the bottoms of the legs 242 such that the backstop
assembly 200 can be easily reoriented in order to expose the
different sides 220, 222, 224, 226 of the container 202 to
projectile fire. The wheels 216 of the backstop assembly 200 are
preferably casters so that the backstop assembly 200 can be easily
rotated. Additionally, it will be appreciated that the wheels 216
are preferably equipped with conventional locking mechanisms such
that the backstop assembly 200 will not move upon impact by a
projectile.
[0091] It will be appreciated that the particulate material 214 and
self-healing sheets 212 have the same composition as the
particulate material and self-healing sheets described with respect
to the backstop assembly of FIG. 1. Additionally, it will be
appreciated that the size and number of sides of the container 202
may be varied without departing from the scope of the present
invention. FIG. 23 shows the backstop assembly 200 including a
conventional vacuum assembly 244 mounted to the top panel 238 of
the container 202 by conventional fastening methods such as screws.
In place of the shutters 236, a rectangular trough 246 is connected
to the container 202 adjacent to the container discharge opening
234 for containing the particulate material 214 which exits via
gravity from the discharge opening 234. The vacuum assembly 244
includes a hose 248 having a distal end within the rectangular
trough 246. By activating the vacuum assembly 244, particulate
material 214 and projectiles contained in the trough 246 are
evacuated from the trough 246 thereby enabling the container 202 to
be emptied for the purpose separating out the captured projectiles
and recycling the particulate material 214.
[0092] It will be appreciated that when the backstop assembly 200
is in use, the trough 246 is removed from the container 202 and
replaced with the shutters 236.
[0093] FIG. 24 illustrates another backstop assembly 250 which is
an embodiment of the present invention. The backstop assembly 250
includes a generally rectangular box-shaped container 252 having an
opening 254 for allowing projectiles to enter the container 252.
The opening 254 of the container 250 is covered by a first
self-healing medium 256 such that the projectiles penetrate the
first self-healing medium 256 upon entering the container 252. The
backstop assembly 250 further includes a second self-healing medium
258 which divides the container 252 into first and second chambers
260 and 262. The first and second chambers 260 and 262 of the
container 252 are filled with soft particulate material 264 for
slowing down and capturing the projectiles within the container
252.
[0094] As described above, the container 252 is generally
box-shaped and defines the opening 254 at the front of the
container 252 for allowing entrance of projectiles into the
container 252. The back of the container is preferably enclosed by
a steel back plate 266 positioned opposite from the opening 254.
The back plate 266 is preferably bolted to a frame system 268 which
provides structural support to the container 252.
[0095] The sides of the container 252 are preferably enclosed by a
pair of opposing steel side plates (not shown) which extend between
the front and back of the container 252 and are connected to the
frame system 268 adjacent the back plate 266. It will be
appreciated that the side plates have been omitted from FIG. 24 for
the purpose of better illustrating the backstop assembly 250.
[0096] The top of the container 252 is enclosed by a top panel 272
which is supported by a generally horizontal portion 274 of the
frame system 268. The top panel 272 is removable to enable the
container 252 to be filled with the particulate material 264 from
the top.
[0097] The bottom of the container 252 is preferably enclosed by an
inclined base plate 276 having upper and lower edges 278 and 280
connected to the frame system 268. A rectangular extension plate
282 aligned generally parallel to the back plate 266 is located
adjacent to the lower edge 280 of the base plate 276. The extension
plate 282 has a plurality of discharge openings 284 which allow the
particulate material 264 and spent projectiles to exit the
container 252 via gravity and accumulate in a collection reservoir
286. It will be appreciated that the base plate 276 of the
container 252 may be equipped with an agitator 288, as previously
described in the specification, for encouraging the particulate
material 264 and spent projectiles to migrate through the discharge
openings 284 from the container 252 into the collection reservoir
286.
[0098] As described above, the first self-healing medium 256
encloses the opening 254 at the front of the container 252. The
first self-healing medium 256 is aligned generally parallel to the
back plate 266 and is connected by conventional fastening methods
to the horizontal portion 274 of the frame system 268 at the top of
the container 252 and the extension plate 282 at the bottom of the
container 252. Similarly, the second self-healing medium 258 is
connected to the horizontal portion 274 of the frame system 268 at
the top of the container 252 and the base plate 266 at the bottom
of the container 252. The second self-healing medium 258 is aligned
generally parallel to the first self-healing medium 256 and is
positioned between the first self-healing medium 256 and the back
plate 266 such that the first chamber 260 is defined between the
first self-healing medium 256 and the second self-healing medium
258 and the second chamber 262 is defined between the second
self-healing medium 258 and the back plate 266. Both the first and
second chambers 260 and 262 are filled with soft particulate
material 264 for slowing down and capturing the projectiles within
the container 252.
[0099] In use, projectiles are fired at the front of the backstop
assembly 250. The projectiles penetrate the first self-healing
medium 256 and are slowed down by the particulate material 264 in
the first chamber 260. Only a small percentage of the projectiles
have enough inertia to pass through both the first self-healing
medium 256 and the second self-healing medium 258. Therefore, a
majority of the projectiles are captured within the first chamber
260 while only a few projectiles are captured within the second
chamber 262. Because the first and second chambers 260 and 262 are
separated by the second self-healing medium 258, the first chamber
260 can be emptied of its particulate material 264 and captured
projectiles without emptying the second chamber 262.
[0100] The division of the container 252 into two separate chambers
260 and 262 is significant because the first chamber 260 captures a
majority of the projectiles and therefore needs to have its
particulate material 264 replaced more often than the second
chamber 262. By employing two chambers 260, 262, it is not
necessary to replace all of the particulate material 264 in the
container 252 when the particulate material closest to the source
of the projectile fire reaches full capacity. Instead, only the
particulate material 264 in the first chamber 260 needs to be
regularly replaced. The particulate material 264 in the second
chamber 262 is replaced at much less frequent intervals than the
particulate material 264 in the first chamber 260 thereby improving
the cost effectiveness of the backstop assembly.
[0101] It will be appreciated that the details regarding the
particulate material 264 and the first and second self-healing
mediums 256, 258 have been previously described in the
specification.
[0102] Turning now to FIGS. 25 and 26, there is illustrated yet
another projectile trap assembly 300 in accordance with the
principles of the present invention. Projectile trap assembly 300
includes a support frame 310 having a front wall 314 and rear wall
316 supporting an inclined member 311. Supported by the upper
surface 312 of inclined member 311 is a particulate flowable
granulate material 320.
[0103] The upper surface 312 is inclined relative to the line of
the projectiles, which typically is substantially parallel to
ground. As illustrated, the upper surface 312 may be inclined
substantially at the angle of repose A of the particulate granulate
material, thereby providing a constant depth of granulate material
330 over the entire upper surface 312 of inclined member 311. In
the exemplary embodiment, the distance D between the plane of the
particulate granulate material 320 upper surface 332 and the plane
of the support frame upper surface 312 is about 15 inches.
[0104] The inclined member 311 is adjustably supported on front
wall 314 and rear wall 316. The lower ends of the front wall 314
and rear wall 316 in turn may be supported by a base member 318 or
ground 350. For height-adjustment, an extendible portion 315, 317
may be provided on each wall 314, 316 for adjusting the height of
the frame assembly 300 and thereby elevating the inclined member
311 with respect to the bottom member 318 or ground 350.
[0105] The rear wall 316 may further include an upper end 320
extending upward beyond the support frame inclined member 311. A
shoulder 322 may extend outward from the upper end 320 of the rear
wall 316 over the inclined member 311 of the assembly 300 so as to
form an open-faced reservoir 324 for holding a reserve portion 334
of the particulate granulate material 330. Shoulder 322 may be
coupled to or integral with rear wall 316.
[0106] The reserve portion 334 of the particulate granulate
material 330 is preferably disposed above and a target portion 336
of the particulate granulate material 330, e.g., the portion of the
granulate material 330 extending over the upper surface 312 and the
front wall 316 of the support frame 310. Conveniently, the
particulate granulate material 330 in the reserve portion 334 flows
into the target portion 336 when the elevation of the upper surface
312 is increased, thereby maintaining the target portion 336 depth
constant over a range of elevations.
[0107] For protecting the upper surface 312 of the frame assembly
300 from damage resulting from projectile impact, a plated surface
313 may be provided. For protecting the front wall from similar
damage, a pair of overlapping panels 342 may be provided.
Preferably, the amount of overlap between the panels 342 varies
with the height of the support frame 300 so that the front wall 314
is not exposed.
[0108] To facilitate entrapment of the projectiles and to prevent
splashing of the granulate particles, projectile trap assembly 300
may further include a self-healing member 346 covering the
particulate granulate material 330, as illustrated in FIG. 25.
Preferably, self-healing member 346 has characteristics as
previously described. As also illustrated in FIG. 25, the
self-healing member 344 may be coupled to a pulley system 340 for
quick and efficient covering and uncovering of the particulate
granulate material 330 thereby facilitating access to the granulate
material for removal of entrapped projectiles. The pulley system
340 may include pulleys 342 coupled to the support frame 310, e.g.,
on shoulder 322, and/or the surroundings, for example, the ceiling
352 of a range.
[0109] For deflecting the projectiles into, for example, the target
portion 336 of the particulate granulate material 330, a deflector
348 may be provided in front of the trap assembly 300, i.e., in the
line of fire of the projectiles. Preferably, the deflector 348 is
mounted to the ceiling 352 and extends from the ceiling 352 to a
position at or below the top of the upper surface 312, thereby
protecting the shoulder 322 of the support frame 310 and the
reserve granulate material 334 held in the reservoir 324.
[0110] Granulate material 330 preferably consists of a particulate
rubber material having an exemplary particle size of about 5-7 mm
and an angle of repose A of approximately 38 degrees from
horizontal. Rubber particles of this size provide a sufficiently
dense medium so as to effectively slow down entering particles
without ordinarily generating enough heat to cause the rubber
material particles to adhere to each other. Advantageously such
rubber material is commercially available as a waste product,
thereby further preserving earth's natural resources.
[0111] As will be appreciated however, the type, size, and
characteristics of the granulate material 330 is provided by way of
example, not of limitation. Other particulate materials may be
used. Moreover, these material and the exemplary rubber material
may further be interspersed with the aforementioned anti-adhesion
material and/or fire-retardent material for increased safety.
[0112] The present invention is to be limited only in accordance
with the scope of the appended claims, since others skilled in the
art may devise other embodiments still within the limits of the
claims.
* * * * *