Pneumatic target system

A sensing apparatus is described for use in a target indicating system operative selectively to signal a strike on a target plate. The target indicating system includes an actuator mechanism adapted to be driven by a pressurized gas, conduit and servo control means in flow communication with the actuator mechanism and adapted, in use, to supply gas under pressure to the actuator mechanism. A strike sensing apparatus or assembly is also included, connectible, in use, to the conduit and servo control means. This sensing apparatus includes a housing defining a cylinder therein having one portion thereof adapted to be in flow communication with the source of pressurized gas. A piston is provided being slidably movable in the cylinder. The piston has a bleed channel therein to depressurize the cylinder. A motion-sensitive weight, preferably in the form of a sphere, is supported by the piston and acts on a needle valve to keep the bleed channel closed. This weight is moveable in response to a strike on the target plate, enabling the bleed channel to be uncovered, thereby causing rapid depressurization of the cylinder and a correspondingly rapid lowering of the target. Preferably the weight is a spherical ball and the stem portion of the piston is formed with a spherical seat for supporting said ball. In another preferred form of this apparatus, biasing means are included, supported in the cylinder housing to cause retraction of the piston when the cylinder has been depressurized.

This invention relates to a target indicating system operative selectively 
to signal a strike on a target plate, in addition to enabling movement of 
the target plate to a raised position and a lowered position. More 
specifically, this invention describes a target indicating system that is 
operated pneumatically. 
BACKGROUND OF THE INVENTION 
It is often necessary on a firing range to provide a target that can be 
raised or lowered by remote control, and which, in addition, will fall 
when hit, i.e. when a bullet strikes it. Such a target indicating system 
should require a minimum of maintenance, and often should be ready for 
immediate use after long periods of disuse. In addition, the need to 
provide auxiliary equipment to render such a target indicating system 
operative should also be minimal. 
Target indicating systems have commonly been constructed using components 
operated electrically. Thus, electric cables span the distance between the 
target and a control point where a supply of electrical power is provided. 
An electrical motor, electromagnet or the like is then actuated to place 
the target into an operable condition ready for use. Some kind of 
vibration sensor is attached to the target to signal a strike on the same. 
Such a sensor could, for example, be arranged to cause a light to glow, a 
bell to ring, or otherwise signal a strike on the target. 
Present day target indicating systems have limitations which are aggravated 
by adverse environmental conditions. Indoor firing ranges are frequently 
subject to dusty or sandy conditions. Outdoor firing ranges are also 
subject to these conditions and, as well, are subject to corrosion or 
electrical shorts due to rain, ice or snow. Electrical faults are 
frequently time consuming to locate and repair. An additional disadvantage 
arises from the fact that electrical power must sometimes be provided at 
what might very well be a remote location. Outdoor firing ranges usually 
fall into that catagory. 
SUMMARY OF THIS INVENTION 
The present invention eliminates many of the serious problems associated 
with an electrically powered target indicating system. The present 
invention is embodied in a target indicating system which is largely 
uneffected by a lack of suitable electrical power, extremes of heat, cold 
or humidity, and requires only the provision of a commercially available 
bottle of gas under pressure. Such a supply of pressurized gas serves as 
the source both for operating the system and for signalling a strike on 
the target. 
Accordingly, there is provided in a target indicating system operative 
selectively to signal a strike on a target plate in addition to 
selectively moving the target plate to a raised operative position and a 
lowered inoperative position, the combination of an actuator mechanism 
adapted to be driven by a pressurized gas, the actuator mechanism being 
operatively coupled to the target plate, to cause selective movement 
thereof to said lowered and raised positions; conduit and servo control 
means in gaseous flow communication with the actuator mechanism, said 
conduit and servo control means, in use, being adapted to supply said 
pressurized gas to the actuator mechanism; and a strike sensing assembly 
connectible, in use, to the conduit and servo control means, the sensing 
assembly including a motion-sensitive valve means operative in response to 
a strike on the target plate, to cause a predetermined bleed of the 
pressurized gas thereby to enable selected rapid movement of the target 
plate to the lowered position indicative of a strike. 
In another aspect, the present invention is embodied in an apparatus 
adapted for use in a target indicating system having a target plate, such 
apparatus being operative to indicate a strike on the target plate, and 
comprising; a housing defining a cylinder therein, one portion of the 
cylinder being adapted to be in flow communication with and pressurizeable 
by a source of pressurized gas; a piston having a stem portion and a head 
portion in sealed engagement with the cylinder, and being slideably 
moveable in the cylinder, the piston having a bleed channel therein 
adapted to place the pressurizeable portion of the cylinder in flow 
communication with atmosphere; valve means for closing the bleed channel; 
and a motion-sensitive weight adapted to be removeably supported by the 
stem portion of the piston to activate the valve means to keep the bleed 
channel closed, the weight being supported in a manner so as to be 
displaceable in response to a strike on the target plate to cause 
activation of the valve means to uncover the bleed channel, thereby 
causing rapid depressurization of the cylinder and a correspondingly rapid 
lowering of the target plate to indicate a strike thereof. 
In a more preferred form of this apparatus the motion-sensitive weight is a 
spherical ball, and the stem portion of the piston is formed with a 
spherical seat for receiving and supporting the ball.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In turning to the drawings, FIG. 1 shows schematically a target indicating 
system 10 such as would commonly be used on a small-arms firing range. The 
target indicating system 10 broadly includes a target plate 12 that is 
moveable selectively to a raised operative position and a lowered 
inoperative position by means of an actuator mechanism 14. The actuator 14 
is operated by pressurized gas conducted to it by conduits 16 and 18 and a 
servo valve mechanism 20. The servo valve 20 is supplied with gas under 
pressure by supply lines 22 and 24 which are connected to a supply 26 of a 
dry pressurized gas. A strike sensing assembly in the form of a hit sensor 
30 is connected by a conduit 32 to the conduit 22 supplying pressurized 
gas to the servo valve 20. 
The actuator mechanism 14 generally comprises a piston and cylinder 
arrangement, with gas under pressure being conducted selectively by 
conduits 16 and 18 to opposite ends 15, 17 of the cylinder. Actuator 14 is 
commercially available, e.g., "BIMBA"* Model 316-DXP. The actuator 
mechanism 14 is supported at one end by a pivot pin 40 to a base 42. Rod 
44 of the piston projects from the other end of the actuator 14. This 
extension 44 is pivotally connected at 46 to the target plate 12. The 
target plate 12 is itself pivotally connected at 48 to the base 42. The 
servo control valve 20 functions to cause gas under pressure to be 
conducted by the conduit 16 to the end 15 of the cylinder, causing 
extension of the rod and pivotal movement of the target plate 12 to a 
raised, operative position. In that raised position the target plate 12 
will be visible to the person who is target shooting. Conduction of gas 
under pressure by conduit 18 to the opposite end 17 of the cylinder in 
actuator mechanism 14 causes retraction of the rod and pivotal movement of 
the target plate 12 to a lowered, inoperative position. 
FNT *A Trademark 
The servo control valve 20 is a unit commercially available. One such valve 
suitable for use in the target indicating system 10 is made by Scovill, 
Model Number 41052. Besides including connections for the conduits 16, 18, 
22 and 24, the servo valve 20 also includes two exhaust ports to enable 
depressurization selectively of one or other end of the cylinder of the 
actuator mechanism 14. 
It is also noted here that conduits 22 and 24 contain flow constrictions 
indicated at 50. These can simply be a flow constriction where the conduit 
diameter has been reduced, and functions to limit the volume flow rate of 
gas through the same for purposes to be described below. A reservoir 52 is 
also provided in one of the conduits 22 and 24. Also included in conduit 
22 is a control valve 54. This control valve 54 functions to direct the 
flow of gas under pressure so as to enable the target plate 12 either to 
be raised or lowered. Thus, the control valve 54 is activatable to an "up" 
or "down" position, taken with respect to positioning of the target plate 
12. The control valve 54 is conventional and available commercially. In 
the present instance a control valve Model Number 52383 was used, as 
manufactured by Scovill-Schrader. The conduits 22 and 24 are joined 
together as shown at 56 generally in the vicinity of the control valve 54. 
A single conduit 58 then connects via a flow regulating valve 60 to the 
bottle 26 of gas under pressure. 
The bottled gas is dry and commonly supplied at a pressure of about 2,500 
pounds per square inch reduced to 50 to 100 psi by pressure regulator 60. 
In addition, the conduits which conduct the pressurized gas from the 
pressure regulator 60 to the strike sensing mechanism 30 and target plate 
actuator 14 are preferably made of a polymeric material, such as 
polyethylene or the like, and are of a size having an internal diameter 
from approximately 1/8 to 3/16 inches. Although not shown in FIG. 1, 
placement of the target plate 12 is commonly in the order of 100 to 400 
yards downrange from the supply 26 of bottled gas and the control valve 
54. The supply 26 of pressurized gas is preferably air or nitrogen under 
pressure. Further, this bottled gas is dry, i.e. free of moisture which 
could condense or cause other problems within the hardware comprising the 
target indicating system 10. Typically, a commercially available bottle of 
gas under pressure contains about 240 std. cu. ft., sufficient for about 
three thousand operations of the target. 
Turning now to FIG. 2, there is shown at 100 a preferred form of apparatus 
which makes up the strike sensing mechanism shown at 30 in FIG. 1. This 
apparatus 100 comprises a cylindrical housing 102 having a head portion 
104 and a stem section 106. These two sections 104 and 106 are joined by a 
conically shaped section 108. The head section 104 defines a chamber or 
cavity 110 which is closed and sealed at one extremity thereof by a cover 
112. This cover 112 is provided with an orifice 114 adapted to be 
selectively closed by a one-way valve assembly 116. This valve means 116 
can be a mushroom-type valve biased to a closed position by means of a 
spring, as shown, or could even be in the form of a flap made of an 
elastomeric material. 
The other extremity of the chamber 110 is closed by the stem portion 118 of 
a piston 120 whose head portion 122 is in sealed, slidable engagement with 
the interior walls of a cylinder 124. The cylinder 124 is adapted to be in 
flow communication with the conduit 32 as shown at 126. 
The cylinder 124 is closed at one end 128 thereof, and is provided with a 
spring retaining cavity 130 at the other end thereof. A coil spring 132 is 
contained in the cavity 130, and functions to bias the piston to a 
retracted position. As seen in FIG. 2, one end of the cavity 130 opens 
into the cylinder 124, while the other end is closed and provided with a 
bore hole 134 that defines guide means for the stem portion 118 of the 
piston 120. 
The piston 120 is provided with an internal channel 136 which is in 
communication with a bleed channel 138 and outlet ports 140 provided in 
the free end of the stem section 118. The bleed channel is configured to 
closely receive a needle valve 142. The needle valve 142 is provided with 
an enlarged head section 144 which defines a spherically shaped seat for a 
motion-sensitive weight in the form of a steel ball 146. The exact 
dimensions of the internal channel 136, bleed channel 138 and outlet ports 
140 are not critical, but are related to the volume flow rate of gas 
passed through the constrictions 50. The size of these channels and ports 
136, 138 and 140 must be no smaller than that which would pass a volume 
flow rate of gas at the operating pressure of the system, which exceeds 
the volume flow rate of gas passed by the constrictions 50, again under 
the same operating pressure. 
The following example will illustrate how the target indicating system 10 
and strike sensing mechanism 100 are intended to operate. When it is 
intended to put the target indicating system 10 into operation, say 
following an indefinite period of disuse of the same, a commercially 
obtained bottle of dry gas under pressure is connected to the conduit 58, 
for example, by connection to the pressure regulator 60. It is in this 
instance assumed that during a period of disuse, the control and servo 
valves and actuator mechanisms are not under any gaseous pressure. 
Further, it is assumed that the target plate was in the lowered, 
inoperative position. 
Activation of the control valve 54, i.e. moving a lever or button thereof 
in a direction signifying "up" enables pressurized gas to flow, in this 
instance, through conduit 22 and flow constriction 50 to one inlet to the 
servo valve 20. This valve is so constructed as to subsequently enable the 
pressurized gas to flow into the conduit 16 while opening the other 
conduit 18 to atmosphere by one of the two exhaust ports on that valve. 
The pressurized gas from conduit 16 flows into the cylinder of the 
actuator mechanism 14, causing the piston therein to be moved, thereby 
pivotally moving the target plate 12 to a raised, operative position. 
At the same time, pressurized gas enters the conduit 32 and is conducted to 
the cylinder 124 of the strike sensing apparatus 100. In a depressurized 
conduit, the biasing spring 132 had pushed the piston 120 to a retracted 
position. In that position the spherical ball 146 had been carried or 
conducted automatically by the conically shaped section 108 to a rest 
position in which the ball is seated on the spherical seat 144. The weight 
of the ball 146 ensures that the needle valve 142 is fully seated or 
inserted in the bleed channel 138 to sealably close the same. When 
pressurized gas enters the cylinder 124 it exerts a force against the head 
122 of the piston 120. The strength of the coil spring 132 is relatively 
low, and is so chosen as to be easily overcome by the gaseous pressure 
force against the head 122 of the piston 120. Thus, entry of pressurized 
gas into the cylinder 124 causes the piston to be pushed to an extended 
position in which the ball 146 remains supported on the needle valve seat 
144 but is somewhat above the conical surface of the section 108. 
A bullet striking the target plate 12 generates a considerable shock or 
impact load on that plate and its base 42. Since the strike sensing 
mechanism 30 is disposed on base 42 (see FIG. 1), the shock load is 
translated into vibrations which are transmitted to the stroke sensing 
apparatus 100. These vibrations cause the motion-sensitive steel ball 146 
to be displaced from the seat 144. This enables the gas pressure acting 
within the channel 136 and bleed channel 138 to lift needle valve 142 
sufficiently to uncover or open the outlet ports 140. Gas under pressure 
is thus conducted from the cylinder 124 into the chamber 110. A slight 
amount of pressure in excess of ambient pressure will cause the relief 
valve 116 to open, thus venting the cylinder 124 and chamber 110 to 
atmosphere. 
The flow constriction 50 limits the volume flow rate of gas under pressure 
which can pass through the same, to replace the pressurized gas in conduit 
32 and cylinder 124 now being vented to atmosphere. This causes the 
pressure in the cylinder 124 as well as in conduit 22 and servo valve 20 
to drop. As that pressure drops, the strength of the coil spring 132 comes 
into play, once again causing the piston 120 to be moved to a retracted 
position. It will be evident from FIG. 2 that when the piston 120 is 
retracted, the ball 146 can be guided by the conical section 108 to a rest 
position, again seated on the valve seat 144 comprising the head of the 
needle valve 142. Once the needle valve 142 has been activated to close 
the bleed channel 138 and outlet ports 140, the pressure can again build 
up within the cylinder 124. Such pressure then causes the piston 120 to be 
moved to its extended position. In that position the motion-sensitive ball 
146 is supported on the valve seat 144 of needle valve 142, in a raised 
position above the conical portion 108. In response to the pressure drop 
in conduit 22, servo valve 20 opens an exhaust port thereof to permit 
venting of gas from conduit 16 to the atmosphere and simultaneously opens 
conduit 24 to permit pressurized gas to flow through conduit 18 into the 
end 17 of the cylinder of the actuator mechanism 14, thereby causing the 
piston and its rod 44 to be retracted with consequent movement of target 
plate 12 to a lowered, inoperative position. 
It is noted that full pressurization of the cylinder 124 will not occur 
until the control valve 54 is next actuated, in readiness to again place 
the target plate in a raised operative position. Thus, actuation of the 
control valve 54 again permits gas under pressure to enter the conduit 22, 
flow through the constriction 50 and into one inlet of the servo valve 20. 
That gas under pressure is again conducted via conduit 16 to one side 15 
of the piston of actuator mechanism 14, causing that piston to be moved to 
an extended position while simultaneously raising the target plate 12 to 
an operative position. The entire sequence of activities above-described 
can occur within a few seconds of a strike on the target plate 12. The 
actual time will depend upon the operator controlling activation of the 
target indicating system 10 and manipulation of the "up" control lever or 
button of control valve 54. 
The system above-described is considered to be simple and reliable in 
operation. Since may parts can readily be made of a polymeric material 
such as polyethylene, nylon, polyfluoroethylene, or the like, it will not 
readily be affected adversely by moisture or temperature extremes. 
Further, since the moveable pistons are basically enclosed, and moveable 
parts can be lubricated for life, dust, grit or other particles need not 
constitute a hazard affecting operation of the system. Utilization of 
parts constructed from a polymeric material will also keep costs to a 
minimum. 
The above disclosure has described a number of configurations and 
arrangements falling within the scope of this invention. Certain obvious 
structural modifications will be apparent to those familiar with target 
indicating systems. It is intended that all such modifications and changes 
are to be envisaged herein as are encompassed by the claims below.