Strike arm having a sliding tube that moves linearly

Abstract

A strike arm device for enabling repeated strikes against a ball, comprising a ball, an outer housing, wherein the outer housing has an internal volume, a tube configured to slide axially within the internal volume of the outer housing, the tube is configured to store a string, wherein the string is secured to the ball, and the string is configured to allow the ball to be mounted to a distal end of the tube.

Description

STRIKE ARM HAVING A SLIDING TUBE THAT MOVES LINEARLYFIELD OF THE INVENTION

[0001] The subject matter generally relates to a strike arm used for enabling an object coupled to the arm to be struck.BACKGROUND OF THE INVENTION

[0002] Strike arms used for training strikes of balls are typically specialized equipment designed to help people improve their striking technique, power and accuracy in sports such as baseball, softball, cricket, tennis and golf. These strike arms are designed to simulate the movement and impact of striking a ball with a bat, racket or club, allowing athletes to practice their swings in a controlled environment.

[0003] The strike arms are designed to handle significant forces at a large number of repetitions, for example, several million repetitions, by multiple different persons in a training facility. As such, the strike arms are designed to include many mechanisms to reduce the impact of each hit on the arm's components, hinges, poles and other parts.SUMMARY OF THE INVENTION

[0004] Embodiments include a strike arm device for enabling repeated strikes against a ball, comprising a ball; an outer housing, wherein the outer housing has an internal volume, a tube configured to slide axially within the internal volume of the outer housing, the tube is configured to store a string, wherein the string is secured to the ball, and the string is configured to allow the ball to be mounted to a distal end of the tube.

[0005] In some cases, the sliding tube comprising a sliding tube rear cap configured to absorb forces from the outer housing when the sliding tube is at a rearmost position. In some cases, the sliding tube comprising a sliding tube front end cap having a width wider than an opening of the internal volume, said sliding tube front end cap is configured for limiting a retraction movement of the sliding tube.

[0006] In some cases, the strike arm device further comprising a stopper secured to the string, wherein the stopper is larger than a hole in the sliding tube front end cap, such that the stopper prevents the string from escaping out of the sliding tube.

[0007] In some cases, the strike arm device further comprising a linear guide rail inside the outer housing and a linear rail carriage slide back and forth along the linear guide rail. In some cases, the linear rail carriage is configured to push the sliding tube away from the outer housing. In some cases, the strike arm device further comprising a main pulley and a motor configured to move the main pulley; wherein the main pulley is coupled to the linear rail carriage via a belt. In some cases, the strike arm device further comprising a sensor configured to detect a hit of the ball. In some cases, the strike arm device further comprising a motor configured to move the linear rail carriage.

[0008] In some cases, the outer housing comprises a front-end cap configured to absorb forces when the sliding tube is at its most forward position. In some cases, the device has a strike position in which a distal end of the string is located near a distal end of the sliding tube and a reset position in which the sliding tube is in a forward-most position. In some cases, the strike arm device further comprising a string and magnet mount secured to the string and to the ball. In some cases, the magnets on the magnet mount engage with a magnet on the sliding tube.

[0009] Embodiments include a strike arm device for enabling repeated strikes against a ball, comprising a ball; an outer housing, wherein the outer housing has an internal volume, a tube configured to slide axially within the internal volume of the outer housing, the tube is configured to store a string, wherein the string is secured to the ball, and the string is configured to allow the ball to be mounted to a distal end of the tube; a retracting mechanism configured to push the tube away from the outer housing.

[0010] In some cases, the retracting mechanism comprising a linear guide rail inside the outer housing and a linear rail carriage slide back and forth along the linear guide rail. In some cases, the linear rail carriage is configured to push the sliding tube away from the outer housing. In some cases, the strike arm device further comprising a main pulley and a motor configured to move the main pulley; wherein the main pulley is coupled to the linear rail carriage via a belt. In some cases, the strike arm device further comprising a sensor configured to detect a hit of the ball. In some cases, the strike arm device further comprising a motor configured to move the linear rail carriage.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawingsmakes apparent to those skilled in the art how embodiments of the invention may be practiced.

[0012] In the drawings:

[0013] Figures 1A-1C show the strike arm device with the ball secured to the sliding tube, according to exemplary embodiments.

[0014] Figures 2A-2D show the strike arm device in various positions, according to exemplary embodiments of the subject matter.

[0015] Figures 3A-3D show the strike arm device in various positions, according to exemplary embodiments of the subject matter.

[0016] Figure 4 shows an exploded perspective view of the ball and the arm device, according to exemplary embodiments of the subject matter.DETAILED DESCRIPTION OF THE INVENTION

[0017] Embodiments of the invention disclose a strike arm comprising a sliding tube that can move linearly within a linear bearing. The linear bearing may allow or disallow the sliding tube to rotate within the linear bearing in addition to the linear movement.

[0018] Figs. 1A-1C show the strike arm device with the ball secured to the sliding tube, according to exemplary embodiments. The strike arm may be configured to hold a ball 110, for example, a tennis ball, a baseball, a golf ball, or another object that persons or robots may wish to hit. Ball 110 may be secured to a moving arm structure covered by an outer housing 135, such that, when the ball 110 is hit in a direction axial to outer housing 135, at least some components of the strike arm device move axially inside the outer housing 135.

[0019] Ball 110 may be secured to magnets or other connectors located in a string and magnet mount 115. Some embodiments may include non-magnetic mounts to secure the ball 110 to the string. The string and magnet mount 115 may be attached to ball 110 using adhesive materials, screws, pins and the like. The string and magnet mount 115 may be configured to hold the string that moves inside the outer housing 135 and retracts the ball 110 to a hit position after being hit. The connector placed inside the string and magnet mount 115 may be coupled to connectors located inside or secured to sliding tube front end cap 120. For example, a first magnet is located at the string and magnet mount 115, and a second magnet is located at sliding tube front end cap 120. In some cases, the magnets on either the string and magnet mount 115 or the sliding tube front end cap 120 can be replaced by a piece of ferromagnetic metal such as iron or steel, which would stillallow the two sides to remain attached via magnetic force. Alternatively, the magnets may be replaced with a solenoid or electromagnet to provide the necessary magnetic attraction.

[0020] The string may be secured to the string and magnet mount 115 by a knot at the end of the string which sits in a small pocket in the string and magnet mount 115. Then, when glue is applied to the string and magnet mount 115 to attach to the ball 110, the end of the string becomes infused with glue and will become affixed to the two surrounding parts.

[0021] The strike arm device may comprise a sliding tube 125 configured to slide within the outer housing 135, along the longitudinal axis of the outer housing 135, both in a direction towards motor 160 and in a direction away from motor 160. The outer housing 135 has a volume large enough to accommodate the sliding tube 125. The outer housing 135 comprises front-end cap 130 configured to absorb forces that are imparted when the sliding tube 125, at its most forward position, is hit back to its position within the sliding tube 125.

[0022] The strike arm device may comprise a first arm mounting block 132 and a second arm mounting block 145 configured for mounting the arm. The strike arm device may comprise an accelerometer 140 configured to measure forces and acceleration on the ball 110 or on other components of the strike arm device.

[0023] The strike arm device may comprise a rear-end cap 138 configured to absorb forces from the rear sidewall of the outer housing 135 when the sliding tube 125 is at its rearmost position.

[0024] The strike arm device may comprise a motor 160 configured to move a pulley 165. The pulley 165 is coupled to linear rail carriage 185 via a belt such as a timing belt, chain, or a string. The motor 160 may be configured to move the sliding tube 125 in response to measurements collected by the accelerometer 140.

[0025] The strike arm device may comprise a motor mount 150 configured to connect motor 160 to the outer housing 135.

[0026] Figure 1A shows a side view of the strike arm device. Figure IB shows a rear perspective view without the outer housing 135. Figure 1C shows a rear perspective view with the outer housing 135 present. As such, Figure IB shows plunger 170 (and an optional second plunger on the opposite side of the sliding tube 125), linear guide rail 182, linear guide rail mounting block 180 and linear rail carriage 185. The plunger 170 may be configured to contact the sliding tube rear end cap 175 that is attached to the sliding tube 125 when the sliding tube 125 is located at a forward position,away from the motor 160. The linear guide rail 182 may be connected to outer housing 135 via one or more linear guide rail mounting blocks 180. The linear rail carriage 185 may move linearly along the length of the linear guide rail 182.

[0027] The linear rail carriage 185 may be configured to run into the sliding tube rear end cap 175, such that the linear rail carriage 185 will push the sliding tube rear end cap 175, sliding tube 125, and ball 110 in a forward direction when the linear rail carriage 185 is pushed forward by the motor 160.

[0028] Figures 2A-2D show schematic views of the strike arm device in various positions, according to exemplary embodiments of the subject matter. Figure 2A shows a side view of the strike arm, Figure 2B shows a top view of the strike arm, Figure 2C shows the side view of the strike arm with the sliding tube assembly removed, and Figure 2D shows the top view of the strike arm with the sliding tube assembly removed.

[0029] In the embodiments shown in Figures 2A-2D, the strike arm may be configured to hold a ball 210, for example a tennis ball, a baseball, golfball, or another object that persons or robots may wish to hit. The ball 210 may be secured to a moving arm structure covered by an outer housing 288, such that, when the ball 210 is hit axially towards outer housing 288, at least some components of the strike arm device move inside the outer housing 288. When the ball 210 is hit, the sliding tube 230 may be pushed back, because the sliding tube 230 may be in line with the ball's trajectory. The sliding tube 230 may slide freely backward in the linear bearing 260 until the sliding tube 230 runs into the linear rail carriage 275 or rear end cap 286. The system is then reset for another hit.

[0030] Ball 210 may be secured to magnets or other connectors located in a string and magnet mount 215. The string and magnet mount 215 may be configured to hold string 235. The other end of string 235 may be coupled to the rear end cap 286 using a string anchor 285. The connector placed inside the string and magnet mount 215 may be coupled to connectors located inside or secured to sliding tube front end cap 220. For example, the first magnet is located at the string and magnet mount 215 and a second magnet is located at sliding tube front end cap 220.

[0031] The strike arm device may comprise a sliding tube 230 configured to slide inside the outer housing 288, along the longitudinal axis, both in a direction towards motor 298 and in a direction away from motor 298. The sliding tube 230 may be constrained to slide along the longitudinal axis by a linear bearing 260. The sliding tube 230 is coupled to a stopper 225. The stopper 225 may be secured to the string 235 by tying a knot in the string 235, then clipping the stopper 225 around theknot, for example using a two-part plastic piece that clips to itself, or by gluing the string 235 to the stopper 225. The stopper 225 may be larger than the hole in the sliding tube front end cap 220 and thus prevents the string 235 from escaping out of the sliding tube front end cap 220. Functionally, this prevents the ball 210 from moving more than a short distance away from the sliding tube front end cap 220.

[0032] The sliding tube 230 may comprise a sliding tube rear end cap 270 configured to absorb forces that are imparted from the rear sidewall of the outer housing 288 or rear end cap 286 or linear rail carriage 275 when the sliding tube 230 is at its rearmost position. The structure inside the outer housing 288 may also comprise a spring 262. Spring 262 may be located inside a cylindrical cavity 265 which may be located inside the front end cap 240 that forms the front enclosure of the outer housing 288. The rear part of spring 262 may be coupled to a plunger 268. The outer housing 288 may comprise a front end cap 240 configured to absorb forces when the sliding tube 230 is at its most forward position, when the sliding tube 230 is close to the hit position.

[0033] The motor 298 may be configured to move rotationally, thereby moving a main pulley 295 that may be connected to belt 272. The main pulley 295 may be coupled to a secondary pulley 245. The belt 272 may be held between main pulley 295 and secondary pulley 245. Motor 298 may be coupled to the outer housing 288 via motor mount 290. The motor mount 290 may be moved a small distance relative to the outer housing 288 via short slots in it; when the motor mount 290 is moved away from the outer housing 288, tension on the belt 272 increases. The motor mount 290 may be moved to tension the belt 272. The secondary pulley 245 can freely rotate around a shaft retained by and mounted to the front end cap 240. The front end cap 240 may also hold one or more springs 262 contained within a cylindrical cavity 265 within the front end cap 240 and holds one or more plungers 268 that push against the springs 262. The plunger 268 may have one end that is larger than the other. The hole in the side of each cylindrical cavity 265 may be preferentially smaller than the central part of the cavity 265. Thus, a plunger 268 can be retained within a cavity 265 by virtue of one of its ends being larger than the hole in the side of the cylindrical cavity 265. Spring 262 and plunger 268 may be contained within the cylindrical cavity 265 such that, when the plunger 268 is depressed by the sliding tube rear end cap 270, the plunger 268 compresses the spring 262. Spring 262 may create a return force that pushes out the plunger 268.

[0034] The strike arm device may comprise an accelerometer 292 that is configured to measure forces and acceleration on the outer housing 288 or on other components of the strike arm device,which may occur when ball 210 is struck and when the string 235 or sliding tube assembly transfers the force of the strike to the outer housing 288 or other components of the strike arm device. The accelerometer 292 may be mounted onto the outer housing 288, onto rear end cap 286, onto arm mounting blocks 250, or onto other rigidly-mounted components in the strike arm. The accelerometer 292 is shown in Figures 2A-2D attached to the outer housing 288 but can equally be placed in other locations. The accelerometer 292 may be configured to almost instantly detect when the ball 210 is hit by monitoring when the acceleration of ball 210 in the rearward direction (or the overall magnitude of the acceleration) exceeds a certain threshold. When the ball 210 is hit, a force projected axially along the length of the sliding tube 230 will be generated, causing the assembly to accelerate backward. Additionally, the accelerometer 292 may monitor acceleration in any other direction, as it is exceedingly unlikely for the user to hit the ball 210 perfectly along the axis of the sliding tube 230 without spin.

[0035] The strike arm device may comprise arm mounting blocks 250 configured for mounting the arm within the outer housing 288. The strike arm device may comprise a linear guide rail 257 with a linear rail carriage 275 that can slide back and forth along the linear guide rail 257. The strike arm device may comprise linear guide rail mounting blocks 255 configured for mounting the linear guide rail 257. The linear guide rail 257 is attached to the inner walls of the outer housing 288, for example, using one or more linear guide rail mounting blocks 255, and these linear guide rail mounting blocks 255 are attached to one or more arm mounting blocks 250 through holes in the outer housing 288. The one or more arm mounting blocks 250 enable the strike arm to be secured to a post, robot arm, or other structure so it can be hit during practice.

[0036] The linear rail carriage 275 may secure two ends of belt 272, for example, a timing belt comprised of rubber with teeth and an embedded strengthening layer to increase its longitudinal stiffness while remaining otherwise flexible. The belt 272 may pass over the secondary pulley 245 in the front end cap 240 and around the main pulley 295 at the back end of the strike arm. The main pulley 295 may be driven by a motor or gearmotor 298, which may be connected to the rear end cap 286 via a motor mount 290. In some exemplary embodiments, the rear end cap 286 may include captive nuts that secure the ends of bolts connecting the motor mount 290 to the rear end cap 286. The bolts may pass through slots in the rear end cap 286 so that the motor 298 and main pulley 295 can be moved. When the motor mount 290 is pulled away from the rear end cap 286, the motor mount 290 may apply tension on the belt 272.

[0037] The belt 272 may be used to return the sliding tube 230 and ball 210 to a configuration wherein the ball 210 is ready to be hit again. When the motor 298 turns in one direction, the main pulley 295 may move the belt 272 which, in turn, pulls on the linear rail carriage 275. The linear rail carriage 275 may push against the sliding tube rear end cap 270, pushing it toward the front of the strike arm. To fully reset the strike arm, the linear rail carriage 275 may push the sliding tube rear end cap 270 forward all the way so that sliding tube rear end cap 270 compresses the plungers 268 into the front end cap 240. In this configuration, since the string 235 is a fixed length and is secured to the rear end cap 286, the ball 210 is pulled toward the sliding tube front end cap 220 at the end of the sliding tube 230. The magnets on string 235 and magnet mount 215 may then engage with the magnets on the sliding tube front end cap 220, holding them together. At this stage, the ball 210 may be re-attached to the sliding tube front end cap 220, and the sliding tube 230 may be pushed forward.

[0038] When the motor 298 rotates to reset the strike arm, the motor 298 may be driven for a fixed period of time in this direction, for example, 0.5 seconds. The linear rail carriage 275 may move forward, contact the sliding tube rear end cap 270, and push the sliding tube rear end cap 270 into the plungers 268. The linear rail carriage 275 may remain stalled (not moving) but still pushing forward for some of this time. The motor 298 may have a current limit (maximum current) that allows the motor 298 to remain stationary without overheating and allows the motor 298 to push on these components without breaking from excessive force. This way, the motor 298 can automatically compensate for slack in the string 235. In some cases, the string 235 may slightly extend over time due to repeated stretching. If the motor 298 pushes forward, the string 235 may extend fully and limit the motor's travel. Thus, the motor 298 may push further forward if the string 235 has slightly stretched. If a string 235 or cord is used, the motor 298 may instead move to a fixed known distance to reset the ball 210. In some cases, the subject matter may comprise one or more distance sensors, an encoder on the motor 298, or another method to track the position of the linear rail carriage 275.

[0039] After rotating in a first direction, the motor 298 may rotate in the other direction, driving the belt 272 and pulling the linear rail carriage 275 back toward the rear of the outer housing 288. The linear rail carriage 275 may be pulled until it is close to its travel limit at the rear of the outer housing 288, providing space for the sliding tube 230 to move backward when the ball 210 is hit. When the sliding tube 230 moves backward, the springs 262 that have been compressed by theplungers 268 extend and push the sliding tube rear end cap 270 backward a small distance (for example, in the range of 1-3 centimeters). This provides a small amount of slack in the string 235. This slack is important because, when the ball 210 is hit, ball 210 may rotate quickly and thus require the string 235 to be fed out from the front of the sliding tube front end cap 220 to prevent its rotation from being affected by the string 235. This way, in case the linear rail carriage 275 is at the rear part of the outer housing 288 and the plungers 268 have extended and pushed back the sliding tube 230 a small amount, the device is in a hit position.

[0040] An optional additional energy-dampening element may be installed at the back of the outer housing 288 to provide cushioning to the sliding tube 230 when the sliding tube 230 is pushed in after a ball strike. Specifically, foam, felt, rubber, other padding, springs, or other compressible materials as known in the art can be attached to the inside of the rear end cap 286 or inside the outer housing 288 or to the back of sliding tube rear end cap 270 to provide a dampening force when the sliding tube rear end cap 270 runs into the rear end cap 286 or another structure at the back of the outer housing 288. These may prevent sudden decelerations of the sliding tube rear end cap 270 and sliding tube 230, which may cause components in the strike arm to break from the high forces.

[0041] The sliding tube rear end cap 270 may comprise magnets located towards the plungers 268 and may attach the sliding tube rear end cap 270 to plungers 268 via magnetic force. If the strike arm is moved to different locations with a robotic arm, there may be inertial forces that may move the ball 210 and sliding tube 230 around due to the accelerations and decelerations. Holding the sliding tube rear end cap 270 to the plungers 268 with magnets may resist this motion.

[0042] Instead of the plungers 268 and springs 262 being mounted to the front end cap 240, the plungers 268 and springs 262 may be mounted to the sliding tube rear end cap 270. This may increase the mass of the sliding tube rear end cap 270, potentially negatively affecting the dynamics of the ball 210 when it is hit.

[0043] Instead of an accelerometer 292, embodiments may include alternative techniques to detect a ball hit. These techniques include the following:

[0044] A camera or another optical sensor such as a phototransistor combined with a light-emitting diode can be placed on the inside of the outer housing 288 or capture light through a hole in the outer housing 288. The camera or sensor may be placed near the front of the outer housing 288, behind the position of the sliding tube rear end cap 270 when the strike arm is ready for a ball hit. The optical sensor may determine the timing in which the sliding tube 230 moves backward: theoptical sensor may sense a relatively large distance (in the range of the diameter of the outer housing 288) until the next object before the ball is hit. Then, when the ball 210 is hit and the sliding tube rear end cap 270 moves backward, the sliding tube rear end cap may be too close to the optical sensor and give a different (shorter distance) reading. The different reading would indicate that the ball 210 had been hit.

[0045] Another optional sensor to detect a strike on the ball is an acoustic sensor, such as a microphone, that may detect the audible sound of the ball being hit. Another embodiment of detecting a ball hit may include placing a magnet on the sliding tube rear end cap 270, and mounting a Hall Effect sensor on the outer housing 288 partway down the tube, at a location just behind the location of the sliding tube rear end cap 270 when the ball 210 is ready to be hit. When the magnet in the sliding tube rear end cap 270 moves past the Hall Effect sensor after the ball is hit, a voltage may be created and detected.

[0046] Another embodiment includes creating an electric circuit between different portions of the device when the ball is hit. One embodiment includes creating a conductive path on the sliding tube rear end cap 270 between the locations where two plungers 268 contact it. This may be performed with, for example, placing a steel insert into the sliding tube rear end cap 270 that extended from one side (where one plunger 268 contacted it) to the other side (where the other plunger 268 contacted it). The plungers 268 and the springs 262 may be conductive. In such case, one wire may be connected to the back of one spring 262, and another wire could be connected to the back of another spring 262. One wire could be connected to a positive voltage source (for example, +3.3V) and the other wire could be connected to the input pin of a microcontroller. A pulldown resistor (for example, one kilo Ohm) may be connected between the input pin of the microcontroller and the circuit ground. Then, when the sliding tube rear end cap 270 and either plunger 268 are disconnected, the voltage at the input pin to the microcontroller would change from the positive voltage (+3.3V) to the ground, and the voltage change may be detected by the microcontroller. In this case, magnets may be placed on the sliding tube rear end cap 270 where it connects to plungers 268 to provide a consistent electrical connection.

[0047] A similar electrical circuit may be created between the magnets on the string and magnet mount 215 on the ball 210 and the magnets on the sliding tube front end cap 220. In this case, the wires may be connected to the sliding tube 230 at some point.

[0048] Another embodiment of detecting when the ball is hit may use a measurement device thatcan measure the position of the sliding tube 230 or sliding tube rear end cap 270 relative to the rest of the strike arm, for example the motor. This embodiment may be performed with a linear potentiometer with the movable point connected to the sliding tube rear end cap 270 and the body of the potentiometer connected to the outer housing 288.

[0049] Another embodiment of detecting when the ball is hit may be performed with an optical distance sensor or time-of-flight sensor located on the inside of the rear end cap 286 that measures the distance forward to the sliding tube rear end cap 270. In each of these cases, the distance to the sliding tube rear end cap 270 may change when the ball 210 is hit.

[0050] The subject matter may further disclose additional methods for moving the sliding tube 230 assembly forward and re-connecting the ball 210 to the front. These methods may include: instead of using a belt, using a string that is wrapped around then fastened to the secondary pulley 245; compressed air could be blown in from the back of the strike arm through a hole in the rear end cap 286, pushing the sliding tube 230 forward; a leadscrew or ballscrew could move a carriage 275 forward instead of a belt; or any other linear extension mechanism. In each case, these would push the sliding tube 230 forward to reset the ball after a hit.

[0051] Figures 3A-3D show the strike arm device in various positions, according to exemplary embodiments of the subject matter. In Figure 3 A, the strike arm device is in a position in which the device is ready for the ball to be hit. In this position, the ball 310 is connected to the sliding tube 325, and the sliding tube is at its forward-most position in which it contacts the plungers 369, but in which the springs 362 are extended and the string 340 is not fully tensed. Figure 3B shows the strike arm device shortly after the ball 310 is hit, as the sliding tube 325 slides rearward inside the outer housing. The spring 362 and plunger 369 do not move when the sliding tube 325 slides, since the springs 362 are fully extended just before the ball 310 is hit. The carriage 375 moves rearward, towards the motor 360, before or when the sliding tube 325 slides rearward.

[0052] In Figure 3C, the sliding tube 325 is in a most forward position, in a reset position, the carriage 375 moves forward and pushes the sliding tube forward. In this position, the ball 310 cannot be hit as the string 340 is too tense and will prevent the ball 310 from moving freely. In the forward- most position, the spring 362 is shrunk / compressed in the reset position. Figure 3C also shows secondary pulley 370, outer housing 335, motor 360 and main pulley 365.

[0053] In Figure 3D, the sliding tube 325 is slightly retracted, moving the ball 310 slightly towards the motor. The carriage 375 moves rearwards inside the outer housing 335, away from the ball 310and closer to the motor 360. This provides space for the sliding tube 325 to move rearwards for a strike against the ball 310 without contacting the carriage 375.

[0054] Figure 4 shows an exploded perspective view of the ball and the arm device, according to exemplary embodiments of the subject matter. The ball 410 may be coupled to a string and magnet mount 415 configured to accommodate the ball magnets 420 and the distal end of the string, in the string hole 425. The sliding tube 450 has a front end cap 435 located at a distal part of the sliding tube 430, the part closer to the ball 410. The front end cap 435 comprises arm magnets 430 configured to form a magnetic force with the ball magnets 420, and an arm string hole 440 in which the string exits. The sliding tube 450 is configured to be connected to the ball 410 via the magnets 420 and 430 when in a hit position and to be disconnected from the ball 410 after the ball 410 is hit. While this figure shows four ball magnets 420 and four arm magnets 430, fewer or more magnets could be used at either location, preferably in the range of 1-10. In case magnets are used on one side, one or more pieces of ferromagnetic material such as steel could be used on the opposite side.

[0055] Embodiments may also include a method of enabling repeated strikes against a ball. The method may include hitting a ball. The method may include after hitting the ball, a tube storing a string secured to the ball sliding axially within an internal volume of an outer housing. The method may also include retracting the tube away from the outer housing. The method may also include the string places the ball at a distal end of the tube.

[0056] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

[0057] All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the invention. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims

CLAIMS:

1. A strike arm device for enabling repeated strikes against a ball, comprising: a ball; an outer housing, wherein the outer housing has an internal volume, a tube configured to slide axially within the internal volume of the outer housing, the tube is configured to store a string, wherein the string is secured to the ball, and the string is configured to allow the ball to be mounted to a distal end of the tube.

2. The strike arm device of claim 1, wherein the sliding tube comprising a sliding tube rear cap configured to absorb forces from the outer housing when the sliding tube is at a rearmost position.

3. The strike arm device of claim 1, wherein the sliding tube comprising a sliding tube front end cap having a width wider than an opening of the internal volume, said sliding tube front end cap is configured for limiting a retraction movement of the sliding tube.

4. The strike arm device of claim 3, further comprising a stopper secured to the string, wherein the stopper is larger than a hole in the sliding tube front end cap, such that the stopper prevents the string from escaping out of the sliding tube.

5. The strike arm device of claim 1, comprising a linear guide rail inside the outer housing and a linear rail carriage slide back and forth along the linear guide rail.

6. The strike arm device of claim 5, wherein the linear rail carriage is configured to push the sliding tube away from the outer housing.

7. The strike arm device of claim 5, further comprising a main pulley and a motor configured to move the main pulley; wherein the main pulley is coupled to the linear rail carriage via a belt.

8. The strike arm device of claim 1, further comprising a sensor configured to detect a hit of the ball.

9. The strike arm device of claim 8, further comprising a motor configured to move the linear rail carriage.

10. The strike arm device of claim 1, wherein the outer housing comprises a front-end cap configured to absorb forces when the sliding tube is at its most forward position.

11. The strike arm device of claim 1, wherein the device has a strike position in which a distal end of the string is located near a distal end of the sliding tube and a reset position in which the sliding tube is in a forward-most position.

12. The strike arm device of claim 1, further comprising a string and magnet mount secured to the string and to the ball.

13. The strike arm device of claim 12, wherein magnets on the magnet mount engage with a magnet on the sliding tube.

14. A strike arm device for enabling repeated strikes against a ball, comprising: a ball; an outer housing, wherein the outer housing has an internal volume, a tube configured to slide axially within the internal volume of the outer housing, the tube is configured to store a string, wherein the string is secured to the ball, and the string is configured to allow the ball to be mounted to a distal end of the tube; a retracting mechanism configured to push the tube away from the outer housing.

15. The strike arm device of claim 14, wherein the retracting mechanism comprising a linear guide rail inside the outer housing and a linear rail carriage slide back and forth along the linear guide rail.

16. The strike arm device of claim 15, wherein the linear rail carriage is configured to push the sliding tube away from the outer housing.

17. The strike arm device of claim 15, further comprising a main pulley and a motor configured to move the main pulley; wherein the main pulley is coupled to the linear rail carriage via a belt.

18. The strike arm device of claim 14, further comprising a sensor configured to detect a hit of the ball.

19. The strike arm device of claim 18, further comprising a motor configured to move the linear rail carriage.

20. A method of enabling repeated strikes against a ball, comprising: in response to hitting the ball, a tube storing a string secured to the ball sliding axially within an internal volume of a outer housing, retracting the tube away from the outer housing, the string placing the ball at a distal end of the tube.

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