Abstract: A system for determining potential changes in trajectories of golf shots includes a sensor array sensing swing data relating to a golfer's swing and trajectory data relating to the trajectories of each of a plurality of shots hit by the golfer and a computing arrangement including a data repository and a processor configured to: store in the data repository the swing data and the trajectory data; identify shots hit by the golfer that represent mishits; and determine output data based on the swing data and the trajectory data for all of the shots hit by the golfer that are not identified as mishits, the output data indicating an optimal shot achievable by the golfer.

Abstract: A portable sports rack and delivery system including an elongate rack enclosure, and a method of use thereof are provided. The elongate rack enclosure defines a storage space for accommodating balls stacked one above the other. A delivery opening, disposed at a first end of the elongate rack enclosure, receives, accommodates, and delivers an uppermost ball from the storage space. A base member, attached to a second end of the elongate rack enclosure, supports the stacked balls within the storage space. A release component including a compression spring, disposed on an upper surface of the base member, elastically compresses and expands to elevate and release the uppermost ball from the storage space for delivery through the delivery opening. A training component, operably and adjustably coupled to a rear section of the elongate rack enclosure, extends above the first end of the elongate rack enclosure to assist in training a sportsperson.

Abstract: A basketball shooting aid includes a sidewall having an upper surface, a lower surface, an inner surface, and an outer surface. The upper surface of the sidewall defines an upper orifice and the lower surface of the sidewall defines a lower orifice, wherein the upper orifice has an upper orifice diameter and the lower orifice has a lower orifice diameter. The upper orifice diameter is greater than the lower orifice diameter such that the inner surface defines an intermediate orifice having a continuously tapering diameter, and the lower orifice diameter is substantially similar to the rim diameter of the existing basketball rim. The basketball shooting aid also comprises a shock-absorbing gasket and a damping layer. The shock-absorbing gasket is sandwiched between the sidewall and the existing basketball rim when the basketball shooting aid is retrofitted onto said existing basketball rim.

Abstract: A basketball training device that helps a basketball player learn where to aim when taking a shot including one or more targets that are secured to a basketball rim by an attachment mechanism.

Abstract: Robotic arms or manipulators can be used to toss inventory items within an inventory system. Tossing strategies for the robotic arms may include information about how a grasped item is to be moved and released by a robotic arm to achieve a trajectory for moving the item to a receiving location. A tossing strategy may also use a trajectory that avoids time and/or space reserved for a trajectory of another tossed item. The receiving location can include surfaces and/or other features that can be manipulated for receiving the item based on one or more characteristics of the tossed item and/or a trajectory of the tossed item.

Abstract: Robotic arms or manipulators can be used to toss inventory items within an inventory system. Tossing strategies for the robotic arms may include information about how a grasped item is to be moved and released by a robotic arm to achieve a trajectory for moving the item to a receiving location. A tossing strategy may also use a trajectory that avoids time and/or space reserved for a trajectory of another tossed item. The receiving location can include surfaces and/or other features that can be manipulated for receiving the item based on one or more characteristics of the tossed item and/or a trajectory of the tossed item.

Abstract: Methods and apparatus related to improving player performance for trajectory-based sports are described. In particular, sporting devices are described that can be utilized to improve player performance in basketball. The sporting devices can include a camera-based system configured to capture and analyze the trajectory of a shot taken by a player. The camera-based system can be configured to provide feedback that allows a player to optimize the trajectory mechanics associated with shooting a basketball. In one embodiment, the camera-based system can be used in conjunction with a training aid that is attached to a basketball rim. The training aid can be configured to improve the trajectory mechanics of individuals utilizing the modified basketball rim to practice their shooting.

Abstract: A computer program is disclosed for reconfiguring a property-adjustable golf club. The program receives data input corresponding to a current configuration of an adjustable feature of the golf club, and data input corresponding to trajectory adjustment information. Based on the data input, reconfiguration information is generated, and outputted, that corresponds to one of a plurality of configurations of the adjustable feature of the golf club.

Abstract: A basketball training device for use with a basketball goal including a backboard having a horizontally disposed rim secured thereto. The training device includes a horizontally disposed circular support positioned below the rim which is either secured to the backboard or the rim. A horizontally disposed mounting structure is selectively horizontally rotatably mounted on the circular support. A vertically disposed simulated basketball player is secured to the mounting structure which extends downwardly therefrom. The simulated basketball player has a pair of arms secured thereto which may be moved upwardly or downwardly.

Abstract: Methods and apparatus related to improving player performance for trajectory-based sports are described. In particular, sporting devices are described that can be utilized to improve player performance in basketball. The sporting devices can include a camera-based system configured to capture and analyze the trajectory of a shot taken by a player. The camera-based system can be configured to provide feedback that allows a player to optimize the trajectory mechanics associated with shooting a basketball. In one embodiment, the camera-based system can be used in conjunction with a training aid that is attached to a basketball rim. The training aid can be configured to improve the trajectory mechanics of individuals utilizing the modified basketball rim to practice their shooting.

Abstract: A direct prize-dispensing game dispenses prizes using a crane assembly under control of the game player. The player participates in an underlying game of the prize-dispensing game that is independent from the prize dispensing function of the crane assembly. When the player successfully achieves an object of the game entitling the player to a prize, the prize-dispensing game switches player control to the crane assembly for dispensing an associated prize selection. The player then controls the crane assembly to select a desired prize. The prize-dispensing game keeps the controls to the crane assembly until a prize is dispensed to the player.

Abstract: A disclosed device provides a trajectory detection and feedback system. The system is capable of detecting one or more moving objects in free flight, analyzing a trajectory of each object and providing immediate feedback information to a human that has launched the object into flight, and/or one or more observers in the area. In a particular embodiment, a non-intrusive machine vision system that remotely detects trajectories of moving objects may be used to evaluate trajectory parameters for a basketball shot at a basketball hoop by a player. The feedback information, such as a trajectory entry angle into the basketball hoop and/or an entry velocity into the hoop for the shot, may be output to the player in an auditory format using a sound projection device.

Abstract: An improved basketball training device comprising a substantially semi-elliptical U-shaped rim device, which is designed to allow a user to safely and rapidly install or remove the device from an existing standard sized rim that is attached to a backboard of a raised basketball goal. The training device compels players to use proper arch when shooting in order to pass the basketball through the goal.

Abstract: A system and training method adapted to assist an individual in improving his or her basketball shooting skills and accuracy. The system includes an apparatus and glove that can be used independently or together. The apparatus is adapted for mounting to a basketball rim and includes flexible paddles for mounting to the rim so that the paddles project upwardly from the rim. The glove is adapted to be worn on the shooting hand and includes fingers, wrist and backhand portions. The fingers portion has three separate sleeves interconnected by elastic webs therebetween. The backhand portion interconnects the fingers portion to the wrist portion. The glove is configured so that the three middle fingers of the shooting hand are individually inserted into the sleeves and elastically held together by the webs, while allowing the thumb and outer finger of the shooting hand to spread outward and support the basketball during shooting.

Abstract: A system and training method adapted to assist an individual in improving his or her basketball shooting skills and accuracy. The system includes an apparatus and glove that can be used independently or together. The apparatus is adapted for mounting to a basketball rim and includes flexible paddles for mounting to the rim so that the paddles project upwardly from the rim. The glove is adapted to be worn on the shooting hand and includes fingers, wrist and backhand portions. The fingers portion has three separate sleeves interconnected by elastic webs therebetween. The backhand portion interconnects the fingers portion to the wrist portion. The glove is configured so that the three middle fingers of the shooting hand are individually inserted into the sleeves and elastically held together by the webs, while allowing the thumb and outer finger of the shooting hand to spread outward and support the basketball during shooting.

Abstract: An adjustable basketball device includes a support, a backboard coupled to the support, a mounting structure coupled to the backboard, an adjustment mechanism movably coupled to the mounting structure, and an adjustable rim supported by the mounting structure and engaged with the adjustment mechanism. The adjustable rim is adjustable between a first configuration in which the rim defines an opening with a first diameter, and a second configuration in which the opening of the rim defines an opening with a second diameter different than the first diameter.

Abstract: A free-standing rebound system for use with a table tennis table wherein the system comprises: paired multi-legged telescoping support stands with an uppermost shaft having an uppermost portion with a hole therein; a mounting assembly including a shaft collar, screw spacer dowel pin and a thumbscrew; and a rectangular, framed rebound board having two rebounding surfaces which may be coated in natural and/or synthetic rubber blends and paired wood insert nuts oppositely arranged at the midpoint on two shorter sides. The apparatus is adjustable to orient the rebound board above the table tennis table at any distance from the net, at any latitudinal angle, or behind the back edge of the table opposite the player at any distance, height or angle as required by the abilities and training goals of the player.

Abstract: A disclosed device provides a trajectory detection and feedback system. The system is capable of detecting one or more moving objects in free flight, analyzing a trajectory of each object and providing immediate feedback information to a human that has launched the object into flight, and/or one or more observers in the area. The feedback information may include one or more trajectory parameters that the human may use to evaluate their skill at sending the object along a desired trajectory. In a particular embodiment, a non-intrusive machine vision system that remotely detects trajectories of moving objects may be used to evaluate trajectory parameters for a basketball shot at a basketball hoop by a player. The feedback information, such as a trajectory entry angle into the basketball hoop and/or an entry velocity into the hoop for the shot, may be output to the player in an auditory format using a sound projection device.

Abstract: A disclosed device provides a trajectory detection and feedback system. The system is capable of detecting one or more moving volleyballs in free flight, analyzing a trajectory of each volleyball and providing feedback information to a human that has launched the volleyball into flight, and/or one or more observers in the area. The feedback information may include one or more trajectory parameters that the human may use to evaluate their skill at sending the volleyball along a desired trajectory. In a particular embodiment, a non-intrusive machine vision system that remotely detects trajectories of moving volleyballs may be used to evaluate trajectory parameters for a volleyball hit towards a virtual target area by a player.

Abstract: A system and training method adapted to assist an individual in improving his or her basketball shooting skills and accuracy. The system includes an apparatus and glove that can be used independently or together. The apparatus is adapted for mounting to a basketball rim and includes flexible paddles for mounting to the rim so that the paddles project upwardly from the rim. The glove is adapted to be worn on the shooting hand and includes fingers, wrist and backhand portions. The fingers portion has three separate sleeves interconnected by elastic webs therebetween. The backhand portion interconnects the fingers portion to the wrist portion. The glove is configured so that the three middle fingers of the shooting hand are individually inserted into the sleeves and elastically held together by the webs, while allowing the thumb and outer finger of the shooting hand to spread outward and support the basketball during shooting.

Abstract: An adjustment device for a basketball rim attachment is disclosed. The basketball rim attachment includes a generally C-shaped ring capable of circumferential contraction from its normal unrestrained configuration. The coupling device is employed to cause the circumferential contraction of the ring to facilitate the installation and removal of the basketball rim attachment to and from a rim of a basketball goal.

Abstract: A basketball practice device including a C-shaped ring capable circumferential contraction from its normal unrestrained configuration to reduce the diameter of the rim of a basketball goal including means to facilitate the installation and removal of the same.

Abstract: A basketball training device adapted to be detachably mounted directly on a basketball goal to provide a target at which the player aims and strikes with the basketball in order to improve the form and accuracy of the player's shooting. The device comprises a base with a plurality of projections attached to the base. The plurality of projections are adapted and configured to bend and allow the ball freely move through the goal without substantially affecting the trajectory of the ball and to substantially resume their original position after the ball has passed through the goal.

Abstract: An oversized basketball rim device for retrofitting onto an existing standard sized basketball rim attached to a backboard of a raised goal which increases an opportunity of making a basket when shooting a basketball.

Abstract: A basketball practice device is for use with a basketball rim having a diameter. The practice device includes an annular body, the body having a diameter substantially lesser than the rim diameter, and at least one and preferably a plurality of supports. Each support is connected with the annular body and has a mount disposeable upon a portion of the rim. At least one and preferably a plurality of retainers each have a first end connected with the support, a second end releasably connected with the support, and a central section. Each central section is extendable at least partially about the rim portion such that the rim portion is retained between the support mount and the retainer to connect the practice device with the rim. Further, each retainer includes a generally elastic loop providing the ends and central portion and is extendable to engage with and disengage from the support.

Abstract: A sports-themed game apparatus convertible from a storage configuration to a deployed configuration, and vice versa is disclosed. The sports-themed game apparatus includes a rim and a defense mechanism operable to move from a first position in which the defense mechanism permits a sports implement to pass through the rim, to a second position in which the defense mechanism prevents the sports implement from passing through the rim. The sports-themed game apparatus may further include a return portion configured to return the sports implement to the user after it is propelled/shot toward the rim.

Abstract: A basketball training aid and method requires a player to jump to sufficient height to see a basket over a curtain, and to shoot over the curtain. The training aid comprises an easily adjustable stand for positioning the curtain. The curtain blocks the player's view of the basket. The aid is adjusted to an individual player to challenge the player to achieve a minimum height to see the basket and to shoot over the aid. The player must coordinate jumping, seeing the basket, and releasing the ball at the apex of the jump. As a result, muscle memory is developed thereby improving player performance.

Abstract: A trajectory detection and feedback system is described. The system is capable of detecting one or more moving objects in free flight, analyzing a trajectory of each object and providing immediate feedback information to a human that has launched tile object into flight, and/or one or more observers in the area The feedback information may include one or more trajectory parameters that the human may use to evaluate their skill at sending the object along a desired trajectory. A non-intrusive machine vision system may be used to evaluate trajectory parameters for a basketball shot at a basketball hoop by a player. After the system has evaluated a plurality of shots by the player, the system may provide 1) a diagnosis of their shot consistency, 2) a prediction for improvement based upon improving their shot consistency and 3) a prescription of actions for improving their consistency.

Abstract: A basketball training apparatus for use with a basketball goal is secured to a backboard, the apparatus including a blocking element secured to the backboard. In an embodiment, the blocking element is a generally planar ledge secured to the backboard at a height substantially equal to the height of a top surface of the basketball goal. The generally planar ledge can be constructed to include a center portion extending outwardly from a center of the backboard. A right side portion can extend outwardly from the backboard along a right side of the backboard from the center portion to a right edge of the backboard, and a left side portion can extend outwardly from the backboard along a left side of the backboard from the center portion to a left edge of the backboard.

Abstract: Basketball training apparatus uses a first vertical support member having a lower end adapted to rest on a supporting surface. An elongated guide rod extends in longitudinal direction. An adjustable wrist support is adapted for manual engagement and disengagement of a wrist of a user. A second elongated member is secured rotatably at one end to one end of the rod and extends at right angles thereto. The other end of the second member is secured to the wrist support. A device is secured to the upper end of the member and is manually pivotable about a horizontal axis disposed at right angles to the longitudinal direction, the device providing a guide channel through which the rod extends.

Abstract: A basketball training device can create a mental “target” when shooting a basketball. The device includes an annular shaped member that can be removably attached on top of a rim of a regulation basketball hoop. The annular shaped member includes a flange portion, which substantially covers the rim of the basketball hoop so as to provide a shelf-like image on a top portion of the basketball hoop.

Abstract: A basketball shooting accuracy aid includes a loop member including a top edge, a bottom edge and a peripheral wall extending between the top and bottom edges. The peripheral wall has an inner surface and an outer surface. The loop member has circular shape. An inner diameter of the loop member is at least one inch less than an inner diameter of a basketball rim. A bracket is attached to the loop member and is positioned adjacent to the bottom edge for selectively securing the loop member to the rim such that the loop member extends upwardly above a plane of the rim.

Abstract: An improved basketball training aid comprising a barrier over which a basketball shot must be lofted in order to pass through the basketball goal. The basketball training aid is intended for attachment to a basketball backboard and basketball goal. The basketball training aid comprises a shield formed into a substantially semi-circular shape or a substantially semi-elliptical shape with a gripping means affixed to each end of the shield. In use, each of the gripping means is attached to the front surface of the basketball backboard. The shield is held in place by the gripping means slightly above and substantially parallel to the basketball goal solely by the gripping means, with the upper surface of the shield is positioned above the top surface of the basketball goal and outside the front edge of the basketball goal. The basketball training aid is removed from the front surface of the basketball backboard by detaching each gripping means from the front surface of the basketball backboard.

Abstract: A basketball training apparatus for improving shooting skills and accuracy on all playing levels. The basketball training apparatus is adapted for use with a basketball rim placed above a playing surface, and comprises a base on the playing surface beneath the basketball rim, a plurality of arms extending in radial directions from the base, a plurality of shooting markers spaced apart along the length of each arm, and vision markers attached to the basketball rim. Each vision marker is radially aligned with a corresponding one of the arms. With this arrangement, a user, when standing on one of the shooting markers and facing the basketball rim, is provided with visual shooting assistance as a result of the arm being radially aligned with one of the vision markers located on a region of the basketball rim that is nearest the user.

Abstract: A basketball apparatus is provided that teaches basketball players to make the perfect basketball shot when shooting backboard shots from any location on the basketball court. The basketball apparatus consists of a backboard, a basketball hoop, a supporting bracket located in front of the backboard providing a reflective surface, and a member attached to the supporting bracket and having a target affixed thereon. The member and the supporting bracket coacting to reflect the target and produce a reflective target bulls eye. Upon shooting, if the user aims towards the centerpoint of the reflective target bulls eye and shoots the basketball in the proper trajectory to engage that centerpoint, the basketball, on this trajectory toward the centerpoint, would engage the backboard at a perfect reflection point and, thereby, bounce off the backboard towards the basketball hoop to obtain the perfect basketball shot.

Abstract: A basketball training device including a wheeled dolly with a pair of guide rails extending upwardly from its opposite sides. The guide rails are generally U-shaped in cross-section and open outwardly from the center of the dolly. Slidably positioned within the guide rails is a pair of elongated side members, the upper ends of which carry a transparent panel. Apertures in the guide rails and side members may be axially aligned to admit locking pins so that the height of the panel above the dolly can be adjusted by a user. A user practices the game of basketball by shooting baskets over the transparent panel. In time, the user learns to put the correct arch on his shots.

Abstract: A basketball training device is adapted to be detachably mounted on a rim of a standard basketball goal to improve a player's ability to make successful shots into the goal. The device comprises an arcuate, free-standing vertical wall protruding from an arcuate, semi-cylindrical base that is adapted to fit over the rim. The device is secured in place on the rim by hooks and straps located at each end of the base. The hooks extend under the rim to prevent horizontal movement and straps wrap around the rim and the base and are secured by hook and loop material to prevent vertical movement. Once the device is secured on the rim, the vertical wall extends above the horizontal plane of the rim to deflect basketball shots having an undesirable trajectory.

Abstract: A basketball practice system for providing a portable assembly positionable between the shooter and the basketball hoop for teaching proper arcing when shooting a basketball. The basketball practice system includes a base assembly, a support assembly, and a frame assembly having an opening positionable at a predetermined height between a shooter and a basketball hoop given a pre-determined shooting distance between the shooter and the basketball hoop.

Abstract: A training aid and method for basketball and other sports having a large hoop or “halo” supported on a vertical post for adjustment. The vertical post is mounted on a T-shaped base which supports the large hoop in such a way that a player can take shots through the hoop without contacting the base. Training a player to properly shoot a basketball begins with teaching the proper method of holding the ball over the player's head and using the legs for a small, quick jump. Using the shot training aid, the player jumps and takes a shot with a high arc at the goal. With other sports, the angle and height of the device can be adjusted as desired, but the dominant feature in the invention is that proficiency in all sports requiring projectiles to be accurately impelled toward a target can be improved.

Abstract: Equipment for use in training penalty taking. The equipment for use with a goal comprising goal posts and a cross bar defining a goal area. The goal area is partially occluded by a transparent or translucent barrier the areas harder to reach by a goalkeeper remaining unoccluded.

Abstract: A collapsible playing section is removably attached to a player console and include casters as a stand alone amusement unit. A background includes three vertically aligned hoops, the medially one being rotated in a plane periodically out of alignment with the other two hoops which are stationary. One or more players in a coin operated game toss five balls in an attempt to pass the ball through all three hoops. A spring loaded telescoping link assembly for operating the moving hoop prevents ball jams. Points and prizes are assigned and awarded based on the number of hoops rung by a given player. More or fewer hoops, their speed of motion and the relative position of the movable hoop of hoops differ in different embodiments.

Abstract: The game for perfecting the arc of a basketball as it travels toward a hoop includes a vertically oriented ring which is positioned a predetermined height above and distance away from the basketball, the ring defining a target area through which the basketball must pass to ensure passage through the hoop. Play of the game includes the awarding of points for each basketball shot, with the greatest number of points awarded for a shot wherein the basketball passes through the ring and hoop without contact and no points awarded where the basketball does not at least pass through the ring.

Abstract: A children's basketball backboard and hoop assembly includes a backboard, and a hoop having a rim which is pivotably attached to the backboard, and a net attached to the rim. The assembly further includes an enlarged secondary training rim pivotably attached to the backboard for movement between an operative position wherein the secondary rim is located above the hoop rim in substantially parallel relation to the hoop rim, and a storage position generally parallel to the backboard. The hoop rim is pivotably attached to the backboard for movement between an operative position wherein the rim extends substantially perpendicular to the backboard and a storage position wherein the rim is positioned in closely spaced parallel relation to the backboard. When the secondary training rim is moved to the storage position it is received within a recess extending along an upper peripheral edge of the backboard.

Abstract: A basketball device for improving a player's shooting accuracy and concentration. The device comprises a removable rim that is placed over a regulation rim to decrease the inside diameter of the regulation rim. The device can easily be installed and removed from the regulation rim. By using the device having a smaller inside diameter, the device may also be used to handicap a player or team with a higher skill level than another player or team to facilitate competition between the two players or teams.

Abstract: A basketball free throw training apparatus has a frame having a top horizontal bar. The horizontal bar is adjustably mounted for vertical positioning on the frame, so that the bar can be raised in a horizontal position with respect to the frame and with respect to the floor upon which the frame is mounted. A pair of upstanding closely spaced guidebars extend upwardly from the bar and have a horizontal space therebetween sufficiently wide to permit a basketball to freely pass therebetween. The frame has an extended arm thereon which can be pivoted to a horizontal position and which can extend between the frame and the backboard of a basket so that the frame is accurately positioned from the basket based upon the stature and shooting technique of the user of the equipment. This arm is length adjustable so as to accommodate the spacing requirements of persons of different stature and skill.

Abstract: A basketball practice device wherein an auxiliary target ring or hoop is supported above a standard horizontal basketball hoop or ring in a plane that is disposed at an acute angle from the plane of the supporting ring. A curved basketball guide chute depends downwardly from the supporting ring for guiding a basketball falling through the supporting ring back toward a basketball shooter. This downwardly depending guide chute also serves as a handle mechanism for manipulating the practice device to rotate it on the standard basketball hoop or to remove from or mount it onto the standard basketball hoop.

Abstract: A basketball shooting improvement apparatus includes a base member which includes a front side, a rear side, and two transverse sides extending between the front side and the rear side. The base member is oriented in a first plane, and hook members are connected to the base member. The hook members include downwardly descending hook ends which descend below the first plane, and the hook members extend beyond the front side of the base member. The hook members extend from the transverse sides of the base member. A tension clamp assembly is connected to the base member. A riser member, supported by the base member, extends upward from the base member. The riser member includes a distal end, and a check point assembly is connected to the distal end of the riser member. The riser member may include an ascending riser portion which ascends above the base member. A transverse riser portion is connected to the ascending riser portion. The transverse riser portion extends beyond the hook ends of the hook members.

Abstract: Device for improving the accuracy of shooting a basketball, comprising an annular member shaped to define the desirable path of the shot basketball, a ball striking flap disposed within the annular member, and electronic indicators in communication with the ball striking flap to indicate that a ball, although passing through the device, was shot with a less than ideal trajectory path. In a second embodiment, the device also comprises a user guideline, foot placement pads, means for increasing the visibility of the top annular surface and securing straps for securing the annular member to the standard rim of the basketball goal.

Abstract: Two net support assemblies each comprise a sleeve and a telescoping member configured to slidingly fit within the sleeve. A net is configured to be stretched between the net support assemblies. The sleeves are each separably attachable to a plate such that the sleeves and the telescoping members extend substantially upwardly from the plate when the apparatus is assembled and ready for use. A floor stand assembly is separably attachable to the plate. A sand bag is separably attachable to the plate to provide stability to the apparatus.

Abstract: A muscle memory basketball training aid and method is provided. The training aid includes a pair of base assemblies and a rectangular frame detachably coupled to the base assemblies. The frame includes a pair of shooting bars and a pair of end bars detachably coupled to the shoot bars. A pair of extension members are detachbly coupled to the base assemblies and to the frame. A locking device is provided that enables longitudinal adjustment of the extension members relative to the base assemblies, for adjusting the height of the frame assembly relative to the base assemblies. The locking device enables each extension member to be adjusted independently of the other, so that the frame assembly may extend obtusely above the base assemblies, to accommodate plural users of different heights.