Device using a pneumatically-actuated carrier to eject projectiles along a trajectory Number:6,807,959 from the United States Patent and Trademark Office (PTO) owispatent A pneumatic device for firing projectiles with a charge of compressed air that accelerates a projectile carrier and the projectile through a barrel. The charge of compressed air is released into the barrel behind the projectile carrier and acts on the projectile carrier to initially accelerate it and a ball or other projectile down the barrel. The diameter of the projectile carrier is slightly less than that of the barrel and it includes a concave recess that receives balls of differing diameters, centering as they are accelerated through the barrel. The barrel is sufficiently long so that the projectile carrier comes to a halt before being ejected from the barrel. An intake for a compressor that develops the charge of compressed air is coupled in fluid communication with the barrel, behind the projectile carrier. Operation of the compressor produces a partial vacuum so that ambient air pressure forces the projectile carrier back to its firing position. An optical sensor is included adjacent to the open end of the barrel to sense when a ball has been loaded, which initiates a firing sequence, to prevent a ball from being fired if the barrel is obstructed, and to determine the velocity of a ball being ejected from the barrel.<H pneumatically, projectiles, Device, using, a, , 6807959.html, Patent, pto, 6807959

Title: Device using a pneumatically-actuated carrier to eject projectiles along a trajectory

Abstract: A pneumatic device for firing projectiles with a charge of compressed air that accelerates a projectile carrier and the projectile through a barrel. The charge of compressed air is released into the barrel behind the projectile carrier and acts on the projectile carrier to initially accelerate it and a ball or other projectile down the barrel. The diameter of the projectile carrier is slightly less than that of the barrel and it includes a concave recess that receives balls of differing diameters, centering as they are accelerated through the barrel. The barrel is sufficiently long so that the projectile carrier comes to a halt before being ejected from the barrel. An intake for a compressor that develops the charge of compressed air is coupled in fluid communication with the barrel, behind the projectile carrier. Operation of the compressor produces a partial vacuum so that ambient air pressure forces the projectile carrier back to its firing position. An optical sensor is included adjacent to the open end of the barrel to sense when a ball has been loaded, which initiates a firing sequence, to prevent a ball from being fired if the barrel is obstructed, and to determine the velocity of a ball being ejected from the barrel.

Patent Number: 6,807,959 Issued on 10/26/2004 to Murdock, et al.

Inventors: Murdock; Douglas B. (Bellevue, WA); Wearn, Jr.; Richard B. (Seattle, WA)
Appl. No.: 09/494,965

Filed: January 31, 2000

Current U.S. Class: 124/61 ; 124/73; 124/77

Field of Search: 124/61,70,71,73,77 42/105

References Cited [Referenced By]

U.S. Patent Documents


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Primary Examiner: Poon; Peter M.
Assistant Examiner: Zerr; John W.
Attorney, Agent or Firm: Anderson; Ronald M.

Claims

The invention in which an exclusive right is claimed is defined by the following:

1. A device for ejecting a projectile, the device comprising: (a) a barrel defining an inner space and having a closed end, and an open end through which the projectile is ejected; (b) a chamber in which a charge of a compressed fluid having a pressure substantially greater than ambient air pressure is developed, said chamber being selectively coupled in fluid communication with the inner space of the barrel, so that the charge of compressed fluid is selectively released into the inner space of the barrel; and (c) a projectile carrier disposed generally adjacent to the closed end of the barrel when in a firing position, the projectile carrier having a rear surface upon which the compressed fluid acts when the charge of the compressed fluid is selectively released into the inner space of the barrel, the projectile carrier having a cross-sectional size sufficiently close to that of the barrel so as to move freely along the inner space of the barrel, while accelerating a projectile conveyed by the projectile carrier through the inner space when the charge of compressed fluid is selectively released into the barrel behind the projectile carrier, said projectile carrier imparting kinetic energy to the projectile when the projectile carrier is forced from its firing position by the charge of compressed fluid and ejecting the projectile from the barrel.

2. The device of claim 1, wherein the barrel is of sufficient length so that the projectile carrier is not propelled from the open end of the barrel, a pressure within the barrel in a volume area between the closed end of the barrel and the projectile carrier dropping to a level below ambient air pressure as the projectile carrier moves toward the open end of the barrel, and ambient air pressure causing the projectile carrier to stop before being ejected from the open end of the barrel.

3. The device of claim 1, wherein the chamber is disposed at the closed end of the barrel, and a valve is disposed between the chamber and the inner space of the barrel, the valve being selectively opened to release the charge of compressed fluid into the inner space behind the projectile carrier.

4. The device of claim 3, wherein the pressure of the compressed fluid developed in the chamber is selectively variable, and a velocity of the projectile as it is ejected is determined by developing an appropriate pressure in the pressure chamber to produce a desired velocity.

5. The device of claim 3, wherein the valve comprises an electromagnet that holds the valve closed when the electromagnet is energized with an electrical current.

6. The device of claim 3, wherein the valve comprises a return spring that returns the valve to a closed position.

7. The device of claim 3, wherein the valve is a high speed valve that when opened, dumps the charge of compressed fluid into the inner space of the barrel, behind the projectile carrier.

8. The device of claim 3, further comprising a compressor that produces the charge of compressed fluid in the chamber.

9. The device of claim 3, further comprising a bleed valve in fluid communication with the chamber, so that the compressed fluid in the chamber can be discharged without opening the valve.

10. The device of claim 8, further comprising a battery that is electrically coupled to the compressor to supply an electrical current to energize the compressor.

11. The device of claim 8, wherein after a projectile has been ejected from the open end of the barrel, the compressor draws air from the inner space behind the projectile carrier to create a partial vacuum within the inner space of the barrel, so that a force on the projectile carrier produced by ambient air pressure moves the projectile carrier back to its firing position.

12. The device of claim 11, wherein the device further comprises a bleed valve that is opened to exhaust compressed air produced by the compressor for at least a portion of a time during which the projectile carrier is being drawn back to its firing position, and then closed so that the compressor achieves a desired pressure in the chamber for ejecting a projectile.

13. The device of claim 12, wherein the bleed valve is opened when the compressor is developing a charge of compressed air in the chamber to eject a projectile at a substantially lower pressure than a previously ejected projectile.

14. The device of claim 12, wherein before the device is de-energized, the bleed valve is opened, thereby releasing any pressure within the chamber, thus preventing any projectile disposed in the barrel from being fired when the device is de-energized.

15. The device of claim 11, wherein the projectile carrier comprises a deformable material that is slightly larger in size than the cross-sectional size of the barrel, and wherein the pneumatic device further comprises a check valve through which the compressor is provided with intake air when the projectile carrier is in the firing position.

16. The device of claim 11, wherein a gap is defined between a periphery of the projectile carrier and an inner surface of the barrel and wherein said gap provides a sufficient amount of seepage so that when the projectile carrier is in its firing position, the compressor draws intake air through the gap.

17. The device of claim 1, wherein the projectile comprises a sports ball.

18. The device of claim 1, wherein a mass of the projectile carrier is substantially less than that of the projectile, so that substantially more of the kinetic energy provided by the compressed fluid is transferred to the projectile than to the projectile carrier.

19. The device of claim 1, wherein the projectile carrier has one of a raised rim and at least one spring clip to receive and retain the projectile within the projectile carrier, thereby generally preventing the projectile from disengaging from the projectile carrier if the barrel is tilted downwardly so that its open end is below the horizontal, until the charge of compressed fluid is released.

20. The device of claim 1, wherein the projectile carrier includes a shaped surface that centers the projectile within the barrel as the projectile is accelerated, minimizing random contacts between the projectile and an internal surface of the barrel, to ensure that the projectile achieves a desired trajectory.

21. The device of claim 20, wherein the shaped surface comprises a recess that can accommodate projectiles of different sizes, so that said projectiles of different size can be ejected using the same barrel and projectile carrier.

22. The device of claim 9, further comprising a controller electrically connected to the compressor to control a magnitude of the pressure developed in the chamber, the magnitude of the pressure being selected by the controller so that the projectile carrier is provided a kinetic energy by the charge of compressed fluid that is sufficient to eject the projectile along a desired trajectory with a desired velocity.

23. The device of claim 22, further comprising a plurality of controls and a display that are electrically coupled to the controller, said controller preventing the device from being operated until a correct password has been entered into the display using at least one of the plurality of controls.

24. The device of claim 22, wherein the controller comprises a microprocessor that is programmed to control the compressor and the valve in accord with a programmed sequence of steps.

25. The device of claim 22, wherein the controller controls the magnitude of the pressure of the compressed fluid in the chamber by controlling a length of time that the compressor is energized.

26. The device of claim 22, further comprising a pressure sensor electrically coupled to the controller and disposed to sense a pressure within the chamber, and wherein the controller controls the magnitude of the pressure of the compressed fluid in the chamber by de-energizing the compressor when said pressure sensor indicates that a desired pressure within the chamber has been obtained.

27. The device of claim 26, further comprising a bleed valve in fluid communication with the chamber, so that when the pressure sensor indicates that the pressure within the chamber exceeds the desired pressure, the compressed fluid in the chamber is discharged through the bleed valve without opening the valve.

28. The device of claim 22, wherein the compressor comprises: (a) an intake in fluid communication with the inner space of the barrel, behind the projectile carrier, such that when the compressor is energized, the compressor creates a partial vacuum that causes the projectile carrier to be pushed back to its firing position by ambient air pressure; and (b) an exhaust in fluid communication with a bleed valve, wherein: (i) said bleed valve enables fluid communication between the exhaust and the chamber when the bleed valve is closed, so that when the compressor is energized and said bleed valve is closed, the compressor fills the pressure chamber with the charge of compressed fluid at a required pressure; (ii) said bleed valve enables fluid communication with ambient air when the bleed valve is open; (iii) the controller opens the bleed valve when a first time period that the compressor is required to operate to ensure that the projectile carrier has returned to the firing position is greater than a second time period that the compressor is required to operate to ensure that the pressure chamber is filled with the compressed fluid at the required pressure, the controller opening the bleed valve and operating the compressor for a time period that is equal to a difference between the first and second time periods, and then closing the bleed valve and operating the compressor for a time period that is equal to the second time period; and otherwise (iv) the controller leaves the bleed valve closed.

29. The device of claim 24, further comprising an optical sensor disposed adjacent to the open end of the barrel and electrically coupled to the microprocessor, the optical sensor producing a signal that is conveyed to the microprocessor, said signal changing in response to a projectile being loaded into the open end of the barrel, causing the microprocessor to initiate a firing sequence by energizing the compressor for a time sufficient to develop a pressure in the chamber that will eject the projectile with the desired velocity.

30. The device of claim 29, wherein the microprocessor is programmed to abort the firing sequence if the signal from the optical sensor indicates that an obstruction has been detected in the barrel.

31. The device of claim 29, further comprising a display that is coupled to the microprocessor, wherein the optical sensor detects a projectile being ejected from the barrel, causing the signal conveyed to the microprocessor to change, said microprocessor determining a velocity of the projectile in response to the signal from the optical sensor and indicating the velocity on the display.

32. The device of claim 1, wherein the device is adapted to be mounted to a tripod.

33. The device of claim 1, further comprising a housing that substantially encloses components of the device.

34. The device of claim 33, wherein the housing comprises a carrying handle.

35. The device of claim 1, further comprising a pivot adjustment and a tilt adjustment to enable a desired trajectory of the projectile to be selectively controlled.

36. The device of claim 1, wherein the device is selectively energized by an internal storage battery or an external power source.

37. The device of claim 36, wherein the internal storage battery is rechargeable.

38. Apparatus for imparting a desired trajectory to a projectile, comprising: (a) a tubular member defining an inner space, said tubular member having a front end and a rear end, the front end being open; (b) a chamber having an inlet and an outlet, said outlet being coupled to the inner space through a port at the rear end of the tubular member via a fluid path that is sealed by a valve that is electromagnetically controlled; (c) a compressor having an intake and exhaust, said exhaust being coupled in fluid communication with the inlet of the chamber, and said intake being coupled in fluid communication with the inner space adjacent to the rear end of the tubular member, said compressor developing a charge of compressed air within the chamber; and (d) a projectile carrier disposed within said tubular member, said projectile carrier having a firing position in which it is disposed in front of the port at the rear of the tubular member, such that when said valve opens, the projectile carrier is initially accelerated toward the front end of the tubular member by the charge of compressed air, thereby imparting kinetic energy to a projectile that is disposed in front of the projectile carrier, so that the projectile is ejected from the front end of the tubular member along the desired trajectory.

39. The apparatus of claim 38, wherein the tubular member is sufficiently long that the projectile carrier stops moving toward the front end of the tubular member before being ejected.

40. The apparatus of claim 38, wherein the chamber is disposed within the rear end of the tubular member.

41. The apparatus of claim 38, further comprising a housing adapted to mount to a supporting tripod, said housing having a pan adjustment and a tilt adjustment to enable the desired trajectory to be selectively set.

42. The apparatus of claim 38, further comprising a shelf extending from the front end of the tubular member to support a projectile being loaded into the tubular member.

43. The apparatus of claim 38, wherein after ejecting the projectile, the intake of the compressor draws air from the inner space of the tubular member, producing a partial vacuum in said inner space that causes the projectile carrier to move through the tubular member to the firing position of the projectile carrier.

44. The apparatus of claim 38, further comprising: (a) an optical sensor disposed adjacent to the front end of the tubular member, such that a projectile being ejected from the tubular member causes a change in a signal produced by the optical sensor; (b) a control panel and a display; and (c) a microprocessor electrically connected to the compressor, the optical sensor, the control panel, the display, and an electromagnetic coil of the valve, said microprocessor controlling a firing sequence to eject a projectile from the tubular member in accord with a parameter entered using the control panel and the display, and responsive to the signal from the optical sensor.

45. The apparatus of claim 44, wherein the microprocessor is programmed to enable an operator to use the control panel to select a desired velocity for the projectile, and to control the compressor so as to determine a pressure of the charge of compressed air within the chamber needed to achieve the desired velocity.

46. The apparatus of claim 44, wherein the microprocessor enables an operator to select a series of programmed firing sequences for ejecting a succession of projectiles from the tubular member.

47. The apparatus of claim 44, wherein the display indicates a velocity of the projectile ejected from the tubular member in response to the signal provided by the optical sensor.

48. The apparatus of claim 44, wherein the microprocessor prevents a projectile from being fired when the signal from the optical sensor indicates that an obstruction has been detected thereby at the front end of the tubular member.

49. The apparatus of claim 44, wherein during the firing sequence, the microprocessor closes the valve, energizes the compressor, using the air drawing into the intake of the compressor to position the projectile carrier in its firing position, and fills the chamber with the charge of compressed air to a pressure required to impart a desired velocity to the projectile when it is ejected, said firing sequence being initiated in response to the signal from the optical sensor indicating that a projectile has been loaded into the front end of the tubular member.

50. The apparatus of claim 44, further comprising: (a) an electrically-actuated bleed valve that is electrically connected to the microprocessor and is connected in a path providing fluid communication between the exhaust of the compressor and the inlet of the chamber, said bleed valve, when opened by the microprocessor, venting the compressor exhaust to ambient, and when closed, enabling compressed air from the exhaust of the compressor to flow into the inlet of the chamber; and (b) wherein the controller opens said bleed valve when a first time period that is sufficient to return the projectile carrier to its firing position is greater than a second time period that is sufficient to fill the chamber with the charge of compressed air at a pressure required to eject the projectile from the tubular member with a desired velocity, the controller first opening the bleed valve for a time period that is equal to a difference between the first and second time periods, and then closing the bleed valve and operating the compressor for a time period that is equal to the second time period.

51. The apparatus of claim 50, further comprising a battery that supplies electrical power to: (a) the microprocessor; (b) the valve that is electromagnetically actuated; (c) the optical sensor; (d) the compressor; and (e) the electrically actuated bleed valve.

52. The apparatus of claim 38, further comprising a housing that substantially encloses the apparatus.

53. The apparatus of claim 52, wherein the housing includes a handle that facilitates carrying the apparatus to a site where it will be used.

54. A device for ejecting a projectile, the device comprising: (a) a barrel defining an inner space and having a closed end, and an open end through which the projectile is ejected; (b) a chamber in which a charge of a compressed fluid having a pressure substantially greater than ambient air pressure is developed, said chamber being selectively coupled in fluid communication with the inner space of the barrel, so that the charge of compressed fluid is selectively released into the inner space of the barrel; and (c) a projectile carrier disposed generally adjacent to the closed end of the barrel when in a firing position, the projectile carrier remaining unattached to a projectile and having a cross-sectional size sufficiently close to that of the barrel so as to move freely along the inner space of the barrel, while accelerating an unattached projectile conveyed by the projectile carrier through the inner space when the charge of compressed fluid is selectively released into the barrel behind the projectile carrier, said projectile carrier imparting kinetic energy to the unattached projectile when the projectile carrier is forced from its firing position by the charge of compressed fluid and ejecting the unattached projectile from the barrel.

55. A method for propelling a projectile along a trajectory, the method comprising the steps of: (a) providing: (i) a tubular member for directing the projectile out from an open end of the tubular member; (ii) a projectile carrier having a cross-sectional size substantially equal to that of the tubular member; (iii) a projectile having a cross-sectional size less than that of the tubular member; and (iv) a charge of compressed fluid; (b) loading the projectile into the tubular member so that the projectile is adjacent to but not attached to the projectile carrier; (c) positioning the projectile carrier in a firing position within the tubular member; and (d) rapidly releasing the charge of compressed fluid into the tubular member so that the compressed fluid acts on the projectile carrier and accelerates the projectile carrier and the projectile through the tubular member, said projectile being thus propelled from the tubular member along the trajectory.

56. A method for propelling a projectile along a trajectory, the method comprising the steps of: (a) providing: (i) a tubular member for directing the projectile out from an open end of the tubular member; (ii) a projectile having a cross-sectional size less then that of the tubular member; (iii) a projectile carrier having a cross-sectional size substantially equal to that of the tubular member, wherein the projectile carrier has one of a raised rim and at least one spring clip to receive and retain the projectile within the projectile carrier, thereby generally preventing the projectile from disengaging form the projectile carrier if the tubular member is tilted downwardly with its open end disposed below the horizontal, until a charge of compressed fluid is released; and (iv) a charge of compressed fluid; (b) loading the projectile into the tubular member so that the projectile is adjacent to the projectile carrier; (c) positioning the projectile carrier in a firing position within the tubular member; and (d) rapidly releasing the charge of compressed fluid into the tubular member so that the compressed fluid acts on the projectile carrier and accelerates the projectile carrier and the projectile through the tubular member, said projectile being thus propelled from the tubular member along the trajectory.

57. A method for propelling a projectile along a trajectory, the method comprising the steps of: (a) providing: (i) a tubular member for directing the projectile out from an open end of the tubular member; (ii) a projectile having a cross-sectional size less then that of the tubular member; (iii) a projectile carrier having a cross-sectional size substantially equal to that of the tubular member; and (iv) a charge of compressed fluid that is developed using a compressor having an intake and an exhaust, said intake being coupled in fluid communication with a volume of the tubular member that is disposed behind the projectile carrier; (b) loading the projectile into the tubular member so that the projectile is adjacent to the projectile carrier; (c) positioning the projectile carrier in a firing position within the tubular member by energizing the compressor to create a partial vacuum in the volume of the tubular member that causes the projectile carrier to be moved through the tubular member and into the firing position; and (d) rapidly releasing the charge of compressed fluid into the tubular member so that the compressed fluid acts on the projectile carrier and accelerates the projectile carrier and the projectile through the tubular member, said projectile being thus propelled from the tubular member along the trajectory.

58. A method for propelling a projectile along a trajectory, the method comprising the steps of: (a) providing: (i) a tubular member for directing the projectile out from an open end of the tubular member; (ii) a projectile having a cross-sectional size less then that of the tubular member; (iii) a projectile carrier having a cross-sectional size substantially equal to that of the tubular member; and (iv) a charge of compressed fluid that is disposed within a chamber, the chamber being in fluid communication with the tubular member along a path that is sealed with a valve; (b) loading the projectile into the tubular member so that the projectile is adjacent to the projectile carrier; (c) positioning the projectile carrier in a firing position within the tubular member; and (d) rapidly releasing the charge of compressed fluid into the tubular member by opening the valve, so that the compressed fluid acts on the projectile carrier and accelerates the projectile carrier and the projectile through the tubular member, said projectile being thus propelled from the tubular member along the trajectory.

59. The method of claim 58, wherein the valve is electromagnetically controlled, the step of rapidly releasing the charge of compressed fluid by opening the valve comprising the step of interrupting an electrical current so that a pressure of the compressed fluid causes the valve to rapidly open.

60. A method for propelling a projectile along a trajectory, the method comprising the steps of: (a) providing: (i) a tubular member for directing the projectile out from an open end of the tubular member; (ii) a projectile having a cross-sectional size less then that of the tubular member; (iii) a projectile carrier having a cross-sectional size substantially equal to that of the tubular member; and (iv) a charge of compressed fluid; (b) loading the projectile into the tubular member so that the projectile is adjacent to the projectile carrier; (c) positioning the projectile carrier in a firing position within the tubular member; (d) rapidly releasing the charge of compressed fluid into the tubular member so that the compressed fluid acts on the projectile carrier and accelerates the projectile carrier and the projectile through the tubular member, said projectile being thus propelled from the tubular member along the trajectory; and (e) determining a velocity of the projectile as it is ejected from the tubular member.

61. The method of claim 60, further comprising the steps of determining whether an obstruction is blocking the tubular member; and if so, aborting the rapid release of the charge of compressed fluid into the tubular member so that the projectile carrier and projectile are not accelerated.

Description

FIELD OF THE INVENTION

This invention relates generally to pneumatic devices for firing a projectile, and more specifically, to a pneumatic device that discharges compressed air behind a projectile to accelerate the projectile down and out of a barrel.

BACKGROUND OF THE INVENTION

Pneumatic or pressurized gas-actuated devices for firing various shaped and sized projectiles are known in the art. These devices are commonly used to propel appropriate sports balls in practice activities for various sports, such as baseball and tennis, although a more common mechanism for propelling practice balls employs friction between a ball and a rotating wheel. Other pneumatic projectile firing devices have been developed for sports such as paintball, where participants engage in mock battles and fire pellets of colored liquid at one another. Still other pneumatic devices, such as B-B guns or pellet guns, are designed for firing small caliber projectiles for target shooting or small game hunting. A very wide variety of different-sized projectiles can be fired with a pneumatic device, and in each of these prior art devices, the projectile being propelled through a barrel is sized to maintain a relatively close fit between the projectile and the bore of the barrel to minimize loss of pressure and reduced efficiency.

A common characteristic of these prior art pneumatic devices is that the size or caliber of the projectile that is pneumatically propelled is thus directly linked to the diameter of the barrel of the device. Consequently, only one size or caliber of projectile can be used with a particular barrel. A tennis ball can therefore not be used with a prior art pneumatic pitching machine that is designed to propel a softball because the sizes of the two different types of ball are so disparate. Furthermore, a projectile that is substantially smaller in diameter than the barrel can randomly strike the sides of the barrel while being accelerated, which will likely adversely affect the accuracy of the projectile's accuracy and may result in damage to the barrel or to the projectile.

An apparent solution to the problem of propelling different diameter projectiles with the same pneumatic device is to provide interchangeable barrels of corresponding different diameters, so that more than one size of projectile can be fired by the same device. However, this solution is not entirely satisfactory, because the barrel of a pneumatic device represents a significant portion of the entire device, and changing barrels is not such a simple task as to be convenient. It would be desirable to develop a device that is capable of firing more than one size of projectile using a single barrel, and without causing damage to the barrel or reducing the accuracy of the projectile's aim.

As mentioned above, prior art pneumatic devices have been used to propel balls with a desired trajectory and velocity for practice activities relating to such sports as baseball and tennis. For example, U.S. Pat. Nos. 4,524,749; 4,834,060; 4,995,371; and 5,121,735 disclose automatic pitching devices that forcibly eject baseballs to enable a person to practice batting the ejected baseballs. Such devices require a barrel specifically designed for a single type of ball, either a baseball, a softball, or a practice ball. A practice ball is the same general size and weight as a baseball, but lacks the stitched seams of a baseball. Some prior art pitching machines, particularly non-pneumatic pitching machines that propel a ball using one or more rotating wheels, do not function well with actual baseballs, because the stitching orientation can change randomly from one ball to the next. The pitching machine wheels may engage the balls differently on successive pitches, adversely affecting the accuracy of successive pitches. Thus practice balls have been developed for use with such devices. In the prior art, a separate device, or at least a separate barrel, has been required for projecting tennis balls, baseballs, and practice balls, even though the relative sizes (diameters) of all three types are similar.

While many of the prior art devices, including non-pneumatic devices, for imparting a desired trajectory to a spoils ball function in a generally satisfactory manner for a particular type of ball, room for improvement in the art still exists. It would be desirable to develop a device for use in pitching balls that has certain desirable features, such as a size and weight sufficiently limited so the device is readily portable and can be transported and set up by a single person, using a portable power source. This device should also have a relatively low cost and should incorporate certain safety features. For example, an enclosure should be provided for moving parts to prevent accidental injury to fingers that might otherwise be caught in the mechanism. A lockout mechanism should be included to prevent a projectile from being fired if an object or individual is blocking the mouth of the barrel. An audible/visual warning should be provided just prior to a projectile being launched. Further desirable features for this type of device, which will appeal to baseball players in particular, would be a display of ball speed, and the ability to deliver projectiles with relatively high accuracy and consistency, in a relatively fast cycle. It would be further desirable to develop a device that is capable of firing objects that are irregular in shape and do not closely conform to a cross-sectional shape of a barrel.

SUMMARY OF THE INVENTION

In accord with the present invention, a device is defined for ejecting a projectile from a barrel using a projectile carrier that when acted upon by a charge of compressed fluid, propels the projectile through the barrel. The barrel defines an inner space and has an open end and a closed end. The projectile carrier is disposed at a firing position within the barrel, generally adjacent to the closed end and is sized to move freely within the barrel. When acted upon by the charge of compressed fluid, the projectile carrier transfers kinetic energy to a projectile and ejects the projectile from the barrel along the desired trajectory.

Preferably, the barrel is of sufficient length so that as the pressure within the barrel drops to a level below ambient air pressure due to the forward motion of the projectile carrier through the barrel, the projectile carrier is prevented from being ejected from the open end of the barrel.

The device also includes a chamber that holds the charge of compressed fluid and a valve that controls the release of the charge of compressed fluid into the barrel behind the projectile carrier. The chamber is coupled in fluid communication with the inner space of the barrel through the valve. When the valve opens, the pressure of the compressed fluid imparts kinetic energy to the projectile carrier. The pressure of the charge of compressed fluid in the chamber is selectively variable, and the velocity of the projectile can be controlled as a function of the pressure in the chamber. The valve is electromagnetically actuated.

In one preferred embodiment, the device includes a rechargeable battery. Further, an external power source or the battery can be selectively chosen to provide an electrical current to energize the device.

A microprocessor is preferably included in a controller to determine a magnitude of pressure developed in the chamber, and thus to achieve a desired velocity. The microprocessor is electrically coupled to the compressor, the valve, a display, and a control panel and implements a firing sequence. The microprocessor prevents the device from being operated until a correct password has been entered into the control panel.

An optical sensor disposed adjacent to the open end of the barrel is electrically coupled to the microprocessor. The optical sensor detects the ejection of a projectile from the barrel, and the microprocessor determines the velocity of the projectile and indicates the velocity on the display. Preferably, the microprocessor prevents the release of the charge of compressed fluid if the optical sensor indicates the presence of an object at the open end of the barrel, thereby preventing a projectile from being ejected when the open end of the barrel is obstructed. Furthermore, the microprocessor initiates a firing sequence when the optical sensor detects a projectile being loaded into the open end of the barrel.

A key feature of the device is the projectile carrier. Preferably, the projectile carrier includes a surface shaped to center the projectile within the barrel during the acceleration of the projectile through the barrel, thereby minimizing random contacts between the projectile and the interior surface of the barrel. This surface is shaped to accommodate different size projectiles, so that the different size projectiles can be ejected using the same barrel.

Another aspect of the present invention is directed to a method that includes steps generally consistent with the description of the apparatus set forth above.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is an isometric view of a pneumatic device in accord with a preferred embodiment of the present invention;

FIG. 2 is a block diagram illustrating the functional relationships among major components of the pneumatic device;

FIG. 3 is a flow chart illustrating the logical steps implemented by the microprocessor of the pneumatic device of FIG. 1 to control the firing cycle;

FIG. 4 is a partially exploded isometric view of the preferred embodiment of FIG. 1;

FIG. 5A is a partially exploded isometric view illustrating details of the barrel of the embodiment of FIGS. 1 and 4;

FIGS. 5B and 5C are side elevational views of two embodiments of a projectile carrier for use in the preferred embodiment of the pneumatic device of FIGS. 1 and 4;

FIG. 6 is a side elevational view of the pneumatic device with a cover removed, to show the interior detail of the device;

FIG. 7 is a side elevational cross-sectional view of the pneumatic device, showing a ball and a carrier for the projectile in a firing position;

FIG. 8 is a side elevational cross-sectional view of the pneumatic device, showing a ball that is being accelerated down the barrel and is approaching the exit of the barrel of the pneumatic device;

FIG. 9 is a side elevational cross-sectional view of the pneumatic device, showing the carrier being drawn back into a firing position to receive the next projectile; and

FIG. 10 is a top plan view of the pneumatic device, with a cutaway portion showing a ball as it just breaking an optical path between a light source and detector disposed near an end of the barrel.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of the present invention is designed to use a charge of compressed air to repeatedly throw or project a baseball or other preferably spherical-shaped projectile along a defined trajectory. Unlike the prior art pneumatic devices for throwing balls, the present invention is able to throw various size (e.g., various diameter) projectiles from a single barrel. It achieves this result by providing a design in which the force developed by the pressurized air is not applied to the projectile, but is instead applied to a lightweight intermediary object having a consistent, defined diameter that is slightly less than that of the barrel. The pneumatic pressure drives the intermediary object down the barrel, and the intermediary object, which is captive within the barrel, drives the projectile or ball with consistent efficiency. Consequently, most of the pneumatic pressure in a compressed air charge is applied to accelerate the projectile.

Various-sized projectiles (sufficiently small to fit within the barrel) can be driven by the intermediary object. In the preferred embodiment, the intermediary object is shaped to maintain spherical projectiles centered within the barrel and away from the sides of the barrel during their acceleration, so that even projectiles sized substantially smaller than barrel do not strike the sides of the barrel while being launched. Thus, projectiles of varying sizes can be accurately fired by the present invention without damaging the barrel or requiring a change in the size of the barrel.

A typical application of the present invention is directed to pitching a baseball or serving a tennis ball to respectively enable batting practice or practice of tennis strokes. However, the present invention is not in any way limited to this application and can also be used for pitching baseballs for fielding practice, pitching perforated plastic WHIFFLE.TM. balls for indoor batting practice, and can project many other types of projectiles, including those that are non-spherical. A preferred embodiment is implemented as a battery powered portable device that is readily hand carried to a desired field location and can be setup for use within minutes. Further details of this preferred embodiment are as follows.

With reference to FIG. 1, a pneumatic device 10 is shown in accord with the present invention. For the purposes of the following discussion, the path of the projectile shown by the arrow in FIG. 1 determines the orientation of the pneumatic device in regard to the terms "forward," "front," "rear," "left," and "right." "Forward" refers to the direction in which the projectile is moving as it accelerates along the path; "front" refers to the portion of pneumatic device 10 that is closest to the path of the projectile as it exits the pneumatic device, and "rear" refers to the portion of the device furthest from the projectile as it exits the pneumatic device. "Right" and "left" reference the point of view of an operator standing at the rear of the pneumatic device and facing forward. Thus, "left" refers to the side of the pneumatic device to the left of the operator, and "right" refers to the side to the right of the operator.

A housing 14 surrounds and substantially encloses the internal components of pneumatic device 10, so that the operator is protected from any injury that might occur due to contact of fingers or hands with the internal components. A carrying handle 12 is provided along the top of housing 14. Preferably, housing 14 is fabricated from an injection-molded plastic that is sufficiently strong and impact resistant to withstand impacts from ricocheting projectiles. Housing 14 includes a control panel 18 and a display panel 20. Control panel 18 includes an ON/OFF-button 11, an UP-button 13, a DOWN-button 17, and an ENTER-button 19. Preferably display panel 20 is a liquid crystal display (LCD), although other types of displays can instead be used, such as one employing light emitting diodes (LEDs). Housing 14 also includes vents 22, which are decorative, but also allow air to circulate through the housing to cool the internal components. A barrel 16 extends from the front of housing 14. An elastomeric guard 30, which serves several functions, is disposed at the front end of barrel 16. Elastomeric guard 30 provides some protection against injury that might otherwise be caused by impacting the end of barrel 16 and also, serves as a supporting surface when loading balls or other projectiles into the open front end of barrel 16.

Also shown in FIG. 1 is a ball 32 that has been forcibly ejected or pitched from pneumatic device 10. Since this embodiment of the present invention is likely to be used for pitching baseballs or "serving" tennis balls, barrel 16 has a diameter that is larger than that of either a baseball or tennis ball. It should be recognized however, that pneumatic device 10 can also be used for propelling other types of projectiles. Unlike prior art devices that have been unable to use the same barrel for both baseballs and tennis balls, the present invention allows a single barrel size to be used to propel projectiles, which are different in size. While it is theoretically possible that in the present invention, a single size barrel of sufficiently large diameter could be used to propel projectiles ranging in size from a basketball to a golf ball, the efficiency of the device for propelling the smaller projectiles would likely be unacceptable, as will be apparent from the discussion that follows. Preferably, the sizes of the different types of projectiles propelled from a single size barrel by pneumatic device 10 should not vary across such a wide range. However, with respect to baseballs and tennis balls, the relative sizes of these projectiles are sufficiently close so that the efficiency of pneumatic device 10 is acceptable for each type of ball.

Incorporated into the mouth of barrel 16 is an optical sensor system 21. The optical sensor system is used to measure the velocity of ball 32 as it leaves the barrel, to initiate the firing cycle of pneumatic device 10 by detecting when a projectile has been loaded into barrel 16, and to prevent pneumatic device 10 from firing when there is an obstruction in the mouth of barrel 16. Further details of optical sensor system 21 are described below.

A tilt adjustment knob 24 is tightened once the vertical angle of barrel 16 relative to the horizontal plane has been adjusted as desired, so that the trajectory of the projectile can be controlled. Shown in phantom view is a tripod 28 and a pan adjustment knob 26. It is expected that pneumatic device 10 will be used in conjunction with a portable support structure such as tripod 28. Pan adjustment knob 26 is tightened after the horizontal trajectory of the projectile has been adjusted as desired by rotating pneumatic device 10 around the vertical axis of tripod 28. In this preferred embodiment, the angular elevation of barrel 16 can be adjusted from about 0.degree. to about 80.degree. degrees, with a free play of less than 1.degree., while the angular pan position in the horizontal plane is fully adjustable throughout 360.degree. at about 1.degree. increments, with a free play of less than 1/2.degree..

Before discussing the detailed structure of the preferred embodiment, it will be helpful to examine the functional relationships of the components of pneumatic device 10, and also the logic used to control pneumatic device 10. FIG. 2 illustrates the functional relationships of the components in a block diagram 180, and FIG. 3 illustrates a flowchart 150 disclosing the logical steps employed to control the firing cycle of the pneumatic device.

In the following description of FIG. 2, the reference numbers used for components shown in subsequent, more detailed drawings are applied to each functional block of the figure. An air compressor intake port 74 is disposed within barrel 16 immediately behind a projectile carrier 114. Compressor intake port 74 provides fluid communication between the intake of compressor 184 and a volume 130 (not shown in FIG. 2) within barrel 16, behind projectile carrier 114. The withdrawal of air from this volume through compressor intake port 74 when compressor 184 is energized acts on projectile carrier 114, causing it to be returned to its firing position. Compressor 184 is also in fluid communication with a compressor exhaust port 76, which in turn is in fluid communication with a bleed valve 80. When open, bleed valve 80 vents the compressor exhaust to atmosphere, as indicated by a block 190, and when closed, enables the compressor exhaust to fill a pressure chamber 128. It should be noted that the velocity of the projectile will be dependent upon the magnitude of the pneumatic pressure developed in pressure chamber 128 at the time of the firing, a greater pressure generally resulting in a higher velocity.

A microprocessor 203 is electrically coupled to compressor 184, bleed valve 80, and an electromagnet 123. As described in detail below, when the firing cycle is initiated, microprocessor 203 energizes compressor 184 to begin pressurizing pressure chamber 128. Microprocessor 203 controls the velocity of the projectile by controlling the length of time that the exhaust or output of compressor 184 is directed into pressure chamber 128 (and is not being vented through bleed valve 80). It should be noted that compressor 184 serves two functions. The intake of compressor 184 creates a partial vacuum in barrel 16 so that atmospheric pressure forces the return of projectile carrier 114 to the firing position, and the exhaust of compressor 184 fills pressure chamber 128. The length of time that compressor 184 needs to operate to return projectile carrier 114 to the firing position is not always equal to that required to achieve the magnitude of pressure within pressure chamber 128 needed to achieve the desired velocity of the projectile about to be fired.

Microprocessor 203 is programmed to recognize that when the velocity selected for the next shot is substantially less than the velocity of the last shot, it is likely that more time will be required to return the projectile carrier to its firing position than is required to fill pressure chamber 128 with the required charge of compressed air. Under this condition, microprocessor 203 will determine the length of time that compressor 184 is required to operate to return projectile carrier 114 to the firing position (which is a function of the length of the barrel and the draw of the compressor) and the time required to fill pressure chamber 128 with the required amount of compressed air. Microprocessor 203 will then open bleed valve 80 (so that compressor exhaust 76 is venting to atmosphere as per block 190) and energize compressor 184 for a first time interval. The first time interval is equal to the difference between the time required to return the projectile carrier to its firing position and the time required to fill pressure chamber 128. After the first time interval has passed, microprocessor 203 will cause bleed valve 80 to close and then will continue to operate compressor 184 for a second time interval, which equals the time required to fill pressure chamber 128 to the desired magnitude of pneumatic pressure. During this second time interval, compressor 184 is simultaneously returning projectile carrier 114 to its firing position and filling pressure chamber 128.

Pressure chamber 128 is in fluid connection with a main valve 100. When held closed by electromagnet 123, main valve 100 seals pressure chamber 128. When microprocessor 203 de-energizes electromagnet 123, main valve 100 opens, and the pressurized air from pressure chamber 128 flow through main valve 100 and acts on projectile carrier 114. Projectile (ball) 32 is seated within projectile carrier 114, and as the pressurized air from pressure chamber 128 causes projectile carrier 114 to accelerate down barrel 16, projectile carrier 114 also moves projectile or ball 32 so that it likewise accelerates down the barrel.

It should be noted that while the preferred embodiment of the invention includes a compressor that pressurizes an internal chamber, it is contemplated that other sources can be used to provide a charge of compressed air or pressurized fluid to propel the projectile carrier. Thus, an external compressor could be used instead of the internal compressor disclosed above. Furthermore, the charge of compressed air could be developed by the combustion of an combustible fluid, such as propane mixed with air, within a confined volume or internal chamber (not shown).

FIG. 3 illustrates the logic used by microprocessor 203 to control the firing cycle of pneumatic device 10. At a block 152 the power for pneumatic device 10 is turned on using ON/OFF-button 11 from control panel 18. The logic then proceeds to a block 154, in which the logic determines if the operator has entered the correct four-digit password. This password is required as a safety feature, since failure to enter the password precludes unauthorized use of pneumatic device 10, e.g., by young children. It should be apparent that a device useful for duplicating baseball pitches and tennis serves can also be potentially harmful to individuals and property if used improperly or in an unsafe manner. The operator enters the password using UP-button 13 and DOWN-button 17 from control panel 18 to respectively increase or decrease a two-digit displayed number from 00-99, and then taps ENTER-button 19 to accept the displayed entry, repeating this process until all digits of the password have been entered. If the password is incorrect, the logic proceeds to a block 156, which provides for displaying an error message to the operator. If the password is correctly entered, the logic proceeds to a block 158 and microprocessor 203 prompts the operator to enter firing parameters, including the desired velocity of the ball. The operator can respectively increase or decrease the velocity of the ball by using UP-button 13 or DOWN-button 17. Control panel 18 can also be used to navigate through a menu to enable the operator to select from a plurality of pre-programmed firing parameters stored by microprocessor 203, or to select functions such as the use of a randomly varying velocity between defined minimum and maximum velocities for successive balls. While the preferred embodiment discussed herein does not include any actuator driven control of elevation and pan angles, it will be apparent that motor drives or other types of actuators can be coupled to pneumatic device 10 to achieve desired settings for both of these parameters, thereby enabling a user to specify all aspects of the trajectory of the ball or other projectile. These and other parameters are implemented under the control of the microprocessor.

Once the parameters are entered, the logic proceeds to a decision block 159 and microprocessor 203 determines if a ball has been loaded into the barrel. In the preferred embodiment, optical sensor system 21 is disposed at the front opening of barrel 16, where it detects the loading of a ball. The projectiles (such as ball 32) are both loaded and ejected through the front of barrel 16. If the response to this query is negative, the logic proceeds to a block 160, and pneumatic device 10 essentially waits until a ball is loaded. Once optical sensor system 21 has detected a ball being loaded, the logic proceeds to a block 162, in which microprocessor 203 energizes electromagnet 123 to close main valve 100 and thereby seals pressure chamber 128. Microprocessor 203 continues to energize electromagnet 123 until the main valve must be opened to complete firing sequence. After a brief pause to ensure that main valve 100 is closed, microprocessor 203 energizes compressor 184. The intake port for compressor 184 is within barrel 16, immediately behind projectile carrier 114. Thus, as compressor 184 begins operating and filling pressure chamber 128 with compressed air to achieve the pressure required to fire ball 32 at the desired velocity, projectile carrier 114 is forced back into its firing position in response to the partial vacuum caused by compressor 184 withdrawing air from the volume disposed behind the projectile carrier, i.e., ambient air pressure forces the projectile carrier back down the barrel. This arrangement ensures that projectile carrier 114 is disposed in the proper firing position (fully back down barrel 16) before the main valve is opened. Microprocessor 203 controls the length of time compressor 184 operates in response to the desired velocity for the ball that was selected by the operator. The higher the desired velocity, the greater the magnitude of the pneumatic pressure within pressure chamber 128 required to achieve that desired velocity. Compressor 184 is shut down to conserve battery power once the desired pneumatic pressure has been stored in pressure chamber 128.

Once pressure chamber 128 has been pressurized to the required pneumatic pressure, the logic proceeds to a decision block 166 in which microprocessor 203 determines if optical sensor system 21 has detected an obstruction at the mouth of barrel 16. If the sensor detects an obstruction, such as a jammed ball, operator's hand, or other object, the logic proceeds to a block 168, the firing sequence is aborted, and an error message is displayed to the operator.

If, at decision block 166, the sensor does not detect an obstruction, the logic proceeds to a block 170, in which microprocessor 203 de-energizes electromagnet 123. With electromagnet 123 no longer holding main valve 100 closed, the pressure of the compressed air in pressure chamber 128 forces the main valve open. The compressed air within the pressure chamber passes through the open main valve and e