FR2480425A1 - Pneumatic drive for target movement - moves it through 90 degrees using quarter-turn actuator with restrictor non return valves - Google Patents

Abstract

The pneumatic drive is for actuating movement of a target through 90 degrees, such as for pistol shooting, and uses a quarter turn actuator. There is a filter, followed by a relief valve to adjust pressure to the actuator. The air goes to two valves which admit air to the actuator and from it. In each valve and actuator chamber is a restrictor non return valve. This allows air in the actuator but it is limited and, when released, pressure drops slowly. A lever from the actuator turns the target through 90 degrees.

Description

 The present invention relates to equipment the purpose of which is to make appear and then disappear (depending on the information received) one or more targets in the particular case of pistol shooting events.

 In these tests, the targets must indeed, according to very precise times, be visible to the shooters then hidden.

 The principle adopted is that of rotating the target 90.

 It should be noted that time criteria (rotation tenps less than 0.3 seconds) and angularity are given by the French Shooting Federation, in correspondence with international regulations.

 Known devices, based on this 90 ° rotation principle, use electrical energy as energy.

They use an electric motor coupled to a reduction gear, the latter transmitting to the target support its half-rotation by a linkage system. A device 9 "limit switch" informs the control device and stops the engine.

 The main drawbacks of this system are as follows: 1) Due to the short time during which the targeting must change positions, it follows that the engine always works at starting intensity (maximum).

2) The starting torque is very high.

3) A braking device is necessary to stop the rotational movement precisely.

 Consequently, we realize the brutality of operation of this system, which makes all the mechanics fragile.

 It should also be noted the need for electrical energy.

 The particularity of the present invention lies in the fact that the energy source used is compressed air.

 The use of this energy to obtain a target rotation of 90 O (since this principle is retained) is based on the use of a cylinder / 4 of turn. The choice of this type of jack is linked to the fact that its movement corresponds to the movement of the targets on the one hand, which simplifies the "mechanical" part on the other hand, it gives the best torque / consumption ratio, the average displacement of the moving part being very weak.

 In addition to the use of this type of cylinder, 3 other special features should be noted - The pressure is only allowed a slightly longer time than the rotation time, then the cylinder is self-inflated ". This particular device saves time during movements.

- A "non-return valve" - restriction device is used to cushion targets at the end of the race.

- One of the solenoid valves is used for opening, the other for closing the targets.

TECHNICAL DESCRIPTION - Pneumatics (figure 1)
There is, first of all, a filter, followed by a pressure reducer making it possible to adjust the pressure which will be admitted on the jack as a function of the torque required and the desired speed of rotation. A lubricating device completes this first assembly.

 The air thus lubricated and under pressure is then directed to t solenoid valves which, according to the information which reaches them, admit it on the jack or, on the contrary, put the latter in the open air.

 Between each of these solenoid valves and each chamber of the cylinder, a set of "non-return valve, restriction" allows the pressurized air to reach the cylinder without significant pressure drop but limits the flow of this cylinder when is vented "by the solenoid valve, causing the pressure in the latter to decrease slowly.

- Mechanics (figure 2)
As can be seen in FIG. 2, a solid lever te of the jack transmits via a coupling arm the rotation at 90 to all of the targets.

 Note the presence of a spring whose force exerted is maximum at mid-stroke.

 The target joints are mounted on ball bearings to reduce friction.

TECHNICAL OPERATION (see Figure 1)
When one of the solenoid valves is stressed, it allows the pressurized air from the regulator and the lubricator to reach one of the chambers of the cylinder.

 When the torque necessary to overcome the mechanical inertia is reached, the movable part of the jack begins its rotation then, accelerates its movement (depending on the pressure applied to it).

 As the movable part of the jack moves, this results in a pressure build-up in the chamber not requested by the electrovalve, due to the presence of the restriction between this chamber and the open air (via the solenoid valve ). This increase in pressure is linked to 2 factors, on the one hand, the speed of the cylinder, on the other hand, the adjustment of the restriction.

 This pressure increase is not linear and, therefore, without action at the start of the movement, it causes it to slow down at the end of the stroke, the pressures tending to balance in each chamber of the jack.

 This system therefore allows on the one hand a rapid start of the rotational movement and on the other hand a progressive damping of this movement at the end of the stroke.

 When the solenoid valve is no longer stressed, it isolates the cylinder chamber from pressurized air and, by restriction, puts it in the open air. The pressure inside this chamber does not drop suddenly, it ensures the positioning of the targets and their stabilization. It should be noted that the cylinder used is equipped with adjustable end stops.

 r 11iittion of the other solenoid valve ensures slack v; t reverse with identical operation.

 Dl; spell having its maximum force in the middle of the course, Fend to oppose a rotation of the targets under the effect of external light: wind, impact of ball. .11 is adjusted sufficiently to maintain the targets but so as not to require too much pressure to control the jack. It is assembled so that the energy it stores during the first half of the movement is restored during the second half.

Finally, it should be noted that this principle of using the jack
Vermet to limit the consumption of compressed air while having sufficient speed.

OPERATION SEEN BY THE USER
The user sees a gradual start while being very fast and a slowdown in the last 10 degrees of rotation. All happening without any brutality.

MAIN ADVANTAGES - Absence of brutality in the operation (as long as the restrictions are correctly set).

- Complete autonomy of the system since 50 liters of air at 10 Bars are sufficient to ensure 150 rotations (the pressure loss being 4 Bars).

- User safety, the solenoid valves being controlled at low voltage on the one hand, on the other hand, the torque, if it is sufficient to ensure rotation, does not risk causing an accident if a person is struck by one of the targets.

- Simplicity of the control mechanics since there is only a transfer of movement.

Claims (3)

1 Pneumatic device, more particularly intended  to maneuver a targeting by rotation of 900,  characterized by the use of a cylinder I / 4 of 2t turn Device according to claim I, characterized by  the use of 2 independent excited solenoid valves  one to open, the other to close, during  only about 0.5 seconds. 30 Device according to claim 2 characterized by  the fact that the cylinder is "pressurized" outside  maneuvers to change positions. 40 Device according to claims 2 and 3, character-  laughed at by the use of the "non-return valve5" assemblies  restriction ", for end-of-travel depreciation.  50 Device according to claim 3 characterized by  the use of a spring ensuring the maintenance of  targets at rest.