Projectile launching apparatus with magnetic bolt valve

Abstract

A projectile launching apparatus includes a bolt (for chambering a projectile) and a bolt valve with a gas passageway for communicating the gas from a chamber housing to a breech assembly. Gas received within the gas chamber is compressed by a piston and communicated through the breech assembly to a projectile. The compressed gas expands in the barrel, thereby propelling the projectile out of the barrel in a single stroke of the piston. The bolt may be returned to an initial position by a magnet and/or spring that is coupled to the valve, and the piston may be returned to an initial position by way of vacuum pressure. The bolt valve may also include a mechanical retention element such as a sear and a release pin. The sear may the bolt in a first position until the piston from the compressor has moved sufficiently to push the release pin.

Claims

1. A projectile launching apparatus, the apparatus comprising: a power source; a control circuit electrically coupled to the power source; a motor electrically coupled to the power source and responsive to the control circuit; a chamber housing; a piston reciprocally movable within the chamber housing to execute a compression stroke and a return stroke; wherein the motor is configured to drive the compression stroke and return stroke of the piston; a breech assembly; a bolt reciprocally movable within the breech; a projectile; a valve coaxially coupled to the bolt and the valve reciprocally movable with the bolt; a retention element the retention element capable of retaining said bolt in a first position; and a gas passageway disposed between the gas chamber and the bolt for pneumatically connecting said gas chamber and the bolt; wherein during the compression stroke, the piston is configured to move towards an end of the chamber housing for compressing the gas in the gas chamber, the gas passageway communicating the compressed gas to the bolt, the retention element retaining the bolt in a first position until the retention element releases said bolt and upon such release, said bolt moving from said first position to a second position, and during said movement of the bolt from the first position to the second position the valve is opened thus launching said projectile.

2. The projectile launching apparatus of claim 1, wherein the retention element releases the bolt as a result of at least one of gas pressure force, a mechanical force, and an electrical force generated during the operation cycle.

3. The projectile launching apparatus of claim 1, wherein the projectile velocity is controlled by at least one of a bleed valve connected to the gas chamber and a throttling needle in the gas passageway.

4. The projectile launching apparatus of claim 1, further comprising a spring operatively coupled to the bolt for returning said bolt to a first position.

5. The projectile launching apparatus of claim 1, wherein during the compression stroke of the piston the gas in the gas chamber is compressed with a compression exponent greater than 1.1 before the bolt is released.

6. The projectile launching apparatus of claim 1, wherein the retaining force provided by the retention element decreases exponentially as the bolt moves from the first position.

7. The projectile launching apparatus of claim 1, further comprising an air replenishment mechanism, wherein said air replenishment mechanism is adapted to allow atmospheric air to flow into or out of the gas chamber.

8. The projectile launching apparatus of claim 1, wherein the retention element is one of at least one of a magnet a mechanical detent, a frictional interference or a solenoid.

9. The apparatus of claim 1, wherein the volume of uncompressed air between the chamber housing and the projectile before the valve is opened is less than 80% of the volume of the compressed gas in the gas chamber.

10. The apparatus of claim 1 wherein the valve opening time is less than 25 milliseconds.

11. The apparatus of claim 1 further comprising a sensor for controlling a stopping point of the motor in at least one position.

12. A bolt valve apparatus for a projectile launching apparatus, the bolt valve comprising: a motor configured to be electrically driven; a gas chamber containing gas; a pistol reciprocally movable within the gas chamber to execute a compression stroke and a return stroke; a breech assembly; an opening in the breech; a bolt reciprocally movable within the breech; a projectile; a valve coaxially coupled to the bolt and the valve reciprocally movable with the bolt; a retention element the retention element capable of retaining said bolt in a first position until a break-away force of the retention element is exceeded; a gas passageway disposed through the bolt for pneumatically connecting the compressed gas; wherein when the force on the bolt exceeds the break-away force of the retention element, said bolt moves from said first position to a second position; wherein at second position said projectile is chambered into a firing position; wherein at or near said second position the valve is opened to communicate said gas through the bolt to said projectile; and wherein the bolt returns to said first position and the retention element thereafter retains said bolt in said first position until a repeat cycle is initiated.

13. The projectile launching apparatus of claim 12, wherein the break-away force is exceeded by at least one of a gas pressure force, a mechanical force, and an electrical force generated during the operation cycle.

14. The bolt valve apparatus of claim 12, wherein the projectile velocity is controlled by at least one of a bleed valve connected to the gas chamber and a throttling needle in the gas passageway.

15. The bolt valve apparatus of claim 12, wherein the retaining force provided by the retention element decreases nonlinearly or exponentially as the bolt moves from said first position.

16. The bolt valve apparatus of claim 12, wherein the retention element is at least one of a magnet, a mechanical detent, a frictional interference or a solenoid.

17. The apparatus of claim 12, wherein the volume of uncompressed air between the gas chamber and the projectile before the valve is opened is less than 80% of the volume of the compressed gas in the gas chamber.

18. The bolt valve apparatus of claim 12 wherein the valve opening time is less than 25 milliseconds.

19. The bolt valve apparatus of claim 12 further comprising said motor which acts compress the gas in the gas chamber.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) The advantages and features of the present disclosure will become better understood with reference to the following detailed description and claims taken in conjunction with the accompanying drawings, wherein like elements are identified with like symbols, and in which

(2) FIG. 1 is a longitudinal cross-sectional view of the projectile launching apparatus 100, incorporating a slider crank arrangement 23 illustrating a piston 5 of a gas chamber housing 14 moving from a first position towards a second position, according to an exemplary embodiment of the present disclosure;

(3) FIG. 2 is a longitudinal cross-sectional view of the projectile launching apparatus 100, illustrating the piston 5 reaching the second position and allowing air to refill the air chamber 21, according to an exemplary embodiment of the present disclosure;

(4) FIG. 3 is a longitudinal cross-sectional view of the projectile launching apparatus 100, illustrating the piston 5 moving back to its first position compressing air in air chamber 21 and the bolt 16 moving to a closed position to chamber the projectile from the breech into the barrel, according to an exemplary embodiment of the present disclosure;

(5) FIG. 4 is longitudinal cross-sectional view of the projectile launching apparatus 100, illustrating opening of the valve and air flowing through the valve to push the projectile out of the barrel according to an exemplary embodiment of the present disclosure;

(6) FIG. 5 is a view of the projectile apparatus with the piston returning to a first position and the bolt returning to its first position according to an exemplary embodiment of the present disclosure;

(7) FIG. 6 is a longitudinal cross sectional view of the projectile launching apparatus of an alternative valve and bolt arrangement with the bolt held in position by a sear release, according to an exemplary embodiment of the present disclosure;

(8) FIG. 7 is a graph of the retention force vs distance showing the nonlinearity of the magnetic bolt retention element according to an exemplary embodiment of the present disclosure;

(9) FIG. 8 is an expanded view of the magnet and bolt release system according to an exemplary embodiment of the present disclosure; and

(10) FIGS. 9-12 show exemplary operational cycle stages of a projectile launching apparatus, in accordance with an exemplary embodiment of the present disclosure.

(11) Like reference numerals refer to like parts throughout the description of several views of the drawings.

DETAILED DESCRIPTION OF THE DISCLOSURE

(12) The exemplary embodiments described here in detail are for illustrative purposes and are subject to many variations in structure and design. It should be emphasized, however, that the present disclosure is not limited to a particular projectile launching apparatus, as shown and described. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present disclosure. For example, the term intake valve refers to a means of replenishing the air chamber. It can be a check valve, electric valve or even holes in the side of the gas chamber housing the main purpose being to re-establish approximately atmospheric air pressure in the air chamber at one end of the stroke.

(13) The terms first, second, and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms a and an herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. Furthermore, references to gas chamber or air chamber or top dead center (TDC) and bottom dead center (BDC) refer to approximate positions and not meant to limit to exactly that one specific position.

(14) In an embodiment, the front end of the compression piston (5), the gas chamber housing (14) and the gas chamber housing end cap (29) (which in an embodiment captures the magnet for the bolt valve) define the volume of the gas chamber (also referred to as air chamber) (21). At its maximum volume state the gas chamber (21) has a volume that is proportional to the projectile to be fired. For example, for a 3 gram paintball to be launched at 300 fps, a volume in the approximate range of 9 in.sup.3-11 in.sup.3 at standard temperature and pressure conditions, and more preferably 10 in.sup.3, may be used.

(15) Referring to FIG. 1, the cycle is initiated by the user pressing a start switch (10) or trigger that causes power to be directed from the power source (not shown) to the motor (1) through the control circuit (3). The control circuit (3) may be any apparatus for connecting power to the motor (1) for the purpose of initiating a cycle and then removing the power to the motor (1) after the cycle has substantially completed. The slider crank (23) and compression piston (5) assembly (also referred to as a linear air compressor) is returned to substantially the same start position at the end of the cycle. Directing power to the motor (1) causes it to turn, transferring energy through the rotating elements of the system and into the slider crank as shown in FIG. 3. The motor (1) continues to rotate transferring energy through the drive train (9) which is preferably a series of gears forming a reduction apparatus. This in turn rotates the slider crank thereby moving the compression piston (5) away from the bolt valve and draws a vacuum in the gas chamber (21). At this point, the compression piston may pass an intake valve, such as a series of holes (27), or an enlarged section in the compression chamber to allow air to bleed into and replenish the air in the gas chamber (21). Alternatively, a mechanically activated intake valve may be provided and used to replenish the air in the gas chamber housing.

(16) The compression piston continues to move through BDC and then back towards the bolt valve, compressing the air in the gas chamber (21) and the air passageway (13). The bolt valve is specifically a combination valve and bolt mechanism used for chambering a projectile and isolating the air which is compressed within the gas chamber (21) from the projectile (6). In the preferred embodiment the valve is formed by sealing gas passageway 13 using O-ring (15) which seals between valve stem (7) and tube (17). The air in the gas chamber (21) continues to increase in pressure until it overcomes the retention force exerted by the retention element (26). The force required to overcome the retention force is referred to as the breakaway force. In the preferred case the retention element is a rare earth magnet (26) acting on the bolt (16). Once the breakaway force is exceeded, the bolt slides along the sealing tube (17) until the valve stem (7) slides past the seal of the O-ring (15), thus exposing the projectile to the air pressure in the gas chamber. The action of the valve stem moving past the O-ring creates a snap action type valve effect, in that the opening time is extremely short. This is due to the relatively high speed of the valve stem as it is being pushed by the now unbalanced force from the compressed air and rapidly accelerates and moves past the O-ring, which opens the valve (see FIGS. 3 and 11 for example).

(17) Several unexpected performance advantages were found by combining the bolt and the valve as described herein. For example, because the bolt accelerates forward to a high velocity, the projectile begins with a high velocity before the valve is opened. Also, because valve opening speed is critical for efficient projectile acceleration, allowing the bolt to move the chambering distance for the projectile before the O-ring (15) releases from the valve stem (7) reduces the valve opening time to less than 5 milliseconds. Moreover, because the piston is still compressing the air in the chamber as the bolt moves forward, the dead volume is minimized. (Dead volume is defined herein as the uncompressed volume into which the compressed air expands prior to pushing on the projectile.) Additionally, the bolt moving forward at high velocity allows a lighter weight bolt to be used without causing performance loss that would otherwise occur due to bolt reaction or blowback as the gas pressure acts on the bolt when the valve is released. The combination of the above unexpected advantages increased the efficiency of the electric air gun by 20% over the prior designs covered in the inventor's earlier disclosures.

(18) Several parameters were discovered to play importantly in the configuration of the valve (including the combination of valve stem (7) and O-ring (15) and compressed air passageway (13). They include the pressure drop through the compression valve, the speed at which the valve opens and the volume of uncompressed air between the compressed air chamber and the projectile. The bolt valve in the preferred embodiment is referred to as a snap acting valve, in that the valve has an opening speed of less than 10 milliseconds from initial cracking to greater then substantially 70% of full flow. One way to meet this requirement is that the actuation or opening force is approximately a minimum of 1.5 times the maintaining force for the valve. Additionally, it is preferred that the retention force drop off one nonlinearly with distance that the bolt moves from its retained position. An exploded view of the preferred embodiment of the bolt valve is shown in the attached FIGS. 8 through 12. In FIG. 9, the compression valve sealing member (alternately referred to herein as the O-ring (15)) is shown seating up against the valve stem (7). The bolt (16) slides over the compressed air passageway (13), which is internal to tube (17). The bolt is held in position by a retention element (26). These aspects cause the bolt valve to have a breakaway force which, when exceeded, unbalances the restraining force on the bolt and causes it to quickly chamber the ball (or other projectile, it being apparent that projectile (6) is not limited to a ball-configuration or shape for purposes of this disclosure) and open the valve, thereby communicating the compressed gas in the gas chamber and compressed air passageway (13) to the projectile, thereby forcefully driving the projectile out the barrel (31). The breakaway force in such an embodiment is controlled via the retention element (26) (which in this exemplary case is a magnet and any spacing washers (washers not shown)). The bolt assembly consisting of the bolt and valve stem, is held towards the retracted position via at least the frictional force of the sealing O-ring or the retention element, or preferably both.

(19) The result of such a design is that a standard three gram paintball can be accelerated to a speed of 300 fps when the air in the gas chamber (21) is compressed to approximately 150 psi with a volume of approximately 1.1 in.sup.3. It was discovered in earlier disclosures that if the volume of uncompressed air in the compressed air passageway (13) exceeds 10% of the initial uncompressed volume (or 50% of the compressed air volume) formed by the gas chamber that the ball (projectile) velocity is significantly lowered. This disclosure overcomes this limitation in that the compressed air passageway is at same pressure as the gas chamber. It was further discovered that using valves that opened slower then 30 milliseconds also caused a significant loss of velocity. These were unexpected discoveries which led to the ability to practically implement single chamber housing air compressor design with a reliable and efficient projectile chambering and valving mechanism. Using other valves that do not open as quickly or as fully or rob the air stream of energy require more energy and cannot match the rate of fire or efficiency of the present disclosure.

(20) The rapid coupling or air from the gas chamber housing to the projectile yields a very efficient transfer of the stored air energy. The compression piston continues its movement after the projectile has been launched. At this point, the cycle the power can be disconnected from the motor and the compression piston allowed to stop. The movement of the compression piston away from TDC draws a vacuum in the gas chamber which when coupled with the force from the retention element (26) and the spring (20) in the preferred embodiment resets the bolt in the first position and opens the breech such that another projectile can be loaded. This was another unexpected result in that the available time to feed the next projectile increased by 70% over the time shown in the cam driven bolt shown in U.S. Pat. No. 7,984,708.

(21) Once the bolt nears the first position, it may be locked in place with the retention element (which may be a magnet in the preferred embodiment.) The launcher has now completed an exemplary operational cycle and is in position for another cycle. Although the preferred operation has been shown as starting with the piston starting and finishing at TDC, an equivalent operational cycle can be achieved by starting at or near BDC and finishing at or near BDC. A sensor is preferably used to determine when the compression piston is at or near either the TDC or BDC position to allow for repeatable cycle termination.

(22) An alternative embodiment is shown in FIG. 6. In this figure, the bolt is held in position by means of a sear. The sear (25) is triggered when the compression piston has moved sufficient distance to contacts the sear release (18). The sear release disengages the sear from the bolt, thus allowing the bolt to move forward. As the bolt moves forward, it functions similarly as that described in the preferred embodiment. The bolt chambers the projectile and then the valve releases allowing the air in the gas chamber to flow to the projectile and launch it out of the barrel.

(23) In another embodiment, it is advantageous to adjust the projectile velocity. One method for adjusting the velocity is to provide a bleed valve to the gas chamber. This adjustable valve allows for a controlled amount of gas to be bled off during the compression cycle. This reduces the amount of gas available to launch the projectile and is a very simple and cost effective method of velocity control for an electric motor driven compressed air gun using a bolt valve. An unexpected advantage of this type of velocity control is that in the event the motor stalls in the compression cycle, the bleed valve allows the compressed air to bleed out of the air chamber, thus eliminating the potential energy and reducing the likelihood of an accidental firing.

(24) In another embodiment, the disclosure comprises a bolt valve apparatus for an electrically driven projectile launching apparatus. In an embodiment, the bolt valve apparatus comprises a gas chamber containing compressed gas; a breech assembly; an opening in the breech; a bolt reciprocally movable within the breech; an opening for a projectile in the breech; a barrel connected to said breech; a valve coupled to the bolt; a retention element, the retention element capable of retaining said bolt in a first position until a break-away force of the retention element is exceeded; and a gas passageway disposed through the bolt for pneumatically connecting the compressed gas. In an embodiment, when the force on the bolt exceeds the break-away force of the retention element, said bolt moves from said first position to a second position. and at the second position the projectile is chambered into a firing position. In an embodiment, at or near the second position, the valve is opened to communicate compressed gas through the bolt to said projectile. In an embodiment, thereafter, the bolt returns to its first position and the retention element thereafter retains said bolt in the first position until a repeat cycle is initiated.

(25) In such an embodiment, the bolt valve apparatus may comprise a dead volume, such dead volume being between the valve and the exit of the projectile. In a further embodiment, the dead volume contained between the exit of the valve and the projectile may be less than 80% of the volume of the compressed gas in the gas chamber.

(26) In an embodiment of the projectile launching apparatus and/or bolt valve apparatus, it is advantageous to adjust the projectile velocity. One method for adjusting the velocity is to provide a bleed valve to the gas chamber. In another embodiment, the velocity may be adjusted by a throttling needle in the gas passageway. Such a throttling needle may be disposed between the exit of the gas chamber 21 and in the gas passageway 13. By restricting the area that the gas can flow with the throttling needle (for example), the projectile velocity is decreased.

(27) Although specific mechanical and constructive elements are described in the preferred embodiments, equivalent substitution may be done without departing from the spirit of the disclosure.

(28) Circuit Operation:

(29) In a preferred embodiment, the control circuit (3) includes high power switching elements and control circuit inputs. The control circuit inputs in the preferred embodiment include a sensor to indicate position in a cycle and help control the endpoint or stopping point of a cycle, a cycle start switch and a safety switch which is used to power off the device. For a lower cost apparatus at least one of these inputs may be eliminated through the use of cams and linkages. The control circuit (3) can input signals from timers and/or sensors as well as output to an interface or LED's. Looking additionally to FIG. 1, the preferred embodiment uses a start switch (10). This embodiment preferably employs at least one sensor (12) (such as a Hall sensor) and a magnet which moves cooperatively with the linear compressor and compression piston (5) assembly. Further preferred circuit embodiments include, but are not limited to: low battery indicators, pulse control of motor power, communication ports, status displays, lock out fault conditions or inputs for sequential/automatic fire.

(30) Although the aforementioned elements are used in the preferred design, it is understood by those familiar with the art that considerable simplification is possible without departing from the spirit of the disclosure. It is further understood by those skilled in the art that the sensors can be used in conjunction with other circuit elements to allow location at different places and that sensors can be of many forms including but not limited to limit switches, hall effect sensors, photo sensors, reed switches, timers and current or voltage sensors without departing from the spirit of the disclosure.

(31) Although there have been described particular embodiments of the present disclosure it is not intended that such references be construed as limitations upon the scope of this disclosure. The preferred embodiments of the disclosure described here are exemplary and numerous modifications, variations and rearrangements can be readily envisioned to achieve an equivalent result, all of which are intended to be embraced within the scope of the appended claims.