Abstract: For improving damping properties and aerodynamics of a bicycle seatpost, said bicycle seatpost substantially includes three elements. A support element includes a connecting member for connecting to a bicycle saddle, and a holding member for fixing to a seat tube. Said two members are connected to each other by a bending member. At the front side of the bending member, a damping element is adhered, in particular with its entire surface. The damping element is particularly partially surrounded by a shell-shaped form element.

Abstract: A seat adjustment mechanism for a vehicle seat may have a number of first rail pairs, each first rail pair having an upper rail and a lower rail. A height adjustment mechanism may be arranged between the number of first rail pairs and a seat part of the vehicle seat. The height adjustment mechanism may have a number of second rail pairs, each second rail pair may have an upper rail and a lower rail. The number of first rail pairs and the number of second rail pairs can be actuated simultaneously.

Abstract: This invention discloses a tower system in which a telescoping tower with a plurality of tower structures is contained within a rigid transportation container in a substantially horizontal position for transportation, may be extended to a height much greater than its contracted length. The tower may be transported horizontal, repositioned to a vertical position and then the individual tower structures extended and secured via spring pins relative to the adjacent tower structure, the erection of the tower sections may be with external equipment such as a boom truck, or utilizing an internal hydraulic cylinder.

Abstract: A chair-type massage machine includes a base member, a slide member slidable with respect to the base member in a first direction and in the direction opposite to it, and an arm treatment portion rotatably fitted to the slide member at an end part of it in the first direction.

Abstract: An elevation structure for a desk frame includes an inner tube telescopically received in an outer tube fixed to a base. The outer tube includes a bottom plate and a first top plate. A desk board unit is fixed to the inner tube. A telescopic rod is received in the inner tube and has top and bottom ends coupled to the outer and inner tubes, respectively. The inner tube extends through an upper buffer pad disposed below the first top plate. The upper buffer pad has an upper face abutting the first top plate and a lower face for abutting an abutting edge of the inner tube in the highest position. A lower buffer pad is disposed above the bottom plate and includes a lower face abutting the bottom plate and an upper face for abutting a bottom end of the inner tube in the lowest position.

Abstract: A cordless height-adjustable instrument table is disclosed. The table includes a plurality of vertical support legs that are equally spaced at each side of a centralized height-adjustment column that is fixedly attached to the bottom portion of the table. The centralized height-adjustment column is fixedly placed above a four-wheel base that is coupled to a motor housing including a charging port, a rechargeable lithium battery pack, and electronic components being provided therein. The table further includes easy touch buttons for raising and lowering the table and a plurality of table extensions that increase the length and width. In practice, the user can actuate the easy touch buttons until a desired height of the table is obtained. A readily available 12-hour rechargeable lithium battery from retailers or manufactures is integrated for prolonged use of the table.

Abstract: An elevatable supporting device for bearing a display is provided. The elevatable supporting device comprises an upright, an energy storage element, and a bearing module. The upright includes a first surface and a second surface which is non-parallel to the first surface. The energy storage element abuts against the first surface and the second surface and includes a first arm providing a first resistance and a second arm providing a second resistance. A first included angle is defined between the first arm and the second arm. When the energy storage element moves from the highest position to the lowest position, the first included angle decreases so that one of the first resistance and the second resistance may increase in order to maintain a total effective resistance along the first axis. Accordingly, the display may be able to stop at any position between the highest position and the lowest position.

Abstract: A table pedestal for an operating table, comprising a pedestal base for connecting the table pedestal to the floor; a pedestal head support that is adjustable in height for supporting the head of the pedestal; a lifting drive for adjusting the height of the pedestal head support in relation to the base of the pedestal; a cylindrical main guide connecting the pedestal head support to the pedestal base, and serving to provide a vertical guide of the pedestal head support in its height adjustment. An additional stabilizing guide, which also connects the pedestal head support to the pedestal base and provides a vertical guide for the pedestal head support in its height adjustment, reduces the play in rotation of the main guide.

Abstract: A parabolic trough collector module comprising an absorber tube, a parabolic reflector focusing the solar radiation to the absorber tube and with a reflector surface, and at least one support de-vice on which the parabolic reflector is mounted so that it can pivot. The support device includes a support head projecting over the reflector surface in the vertical direction, on which the absorber tube is mounted by a linear bearing structure forming a linear guide.

Abstract: The liftable screen stand has a base assembly, an elevating device, and an assembling device. The elevating device is mounted on the base assembly and has a guiding tube, an elevating tube, a supporting tube, a pedal seat, a pedal, a pushing rod and a pneumatic cylinder. The elevating tube is movable along the guiding tube. The supporting tube is disposed in the guiding tube. The pedal seat is mounted in the base assembly. The pedal is mounted on the pedal seat. The pushing rod abuts against the pedal. The pneumatic cylinder has a gas spring, an activating valve, and an elevatable tube. The gas spring is fixed at the supporting tube. The activating valve is mounted to the gas spring. The elevatable tube is mounted to the gas spring and is fixed with the elevating tube. The assembling device is mounted to the elevating tube.

Abstract: A patient support apparatus including a patient couch and a single supporting pillar on which the patient couch is arranged in an adjustable and cantilevered manner, is provided. The apparatus includes a first rotary frame and a second rotary frame. The first rotary frame rotates about a first axis and encloses the supporting pillar. The second rotary frame rotates about a second axis, rotatably encloses the first rotary frame, and is fixed to the patient couch. The first rotary frame and the second rotary frame form a gimbal mount for the patient couch.

Abstract: Imaging platform assembly includes a platform having a transparent portion, and a support frame that supports the platform at an elevated level, a rotatable camera support coupled to the support frame adjacent to the platform, a camera arm extending from the camera support, and a camera arranged at a free end of the camera arm and having a field of view oriented toward the platform. The camera support is rotatable to cause the camera to move in a path between a position above the platform and a position below the transparent region of the platform and enables imaging of a subject on the platform from above and below the platform. When the camera is fixed to the camera arm and the camera arm is fixed to the camera support, a complete rotation of the camera support causes a complete rotation of the camera around the platform.

Abstract: Modified footrest assembly for a salon chair having an upper and a lower portion configured to latch into a first position and pivot about a point. Modified footrest assembly having a length such that it is configured to support a person's foot in a first position and not protrude beyond a chair when in a second position. Modified, modular footrest assembly configured to mount and unmount from a variety of chairs. Modified, modular footrest assembly having a left and a right side and configured so that each side operates independently.

Abstract: A shoring system for concrete slabs is disclosed. One such system includes a drop head with a beam support member which can be moved between lower and upper positions, and a wedge member which locks the beam support member in its upper position by a translational, sliding movement thereof. Wedge member includes a narrower toe portion and a wider heel portion, and the toe portion is insertable past corresponding engagement surfaces on the post of the drop head, to support the wedge member in its upper position. The beam support member has a lower surface engaged by the wedge member and such lower surface is longitudinally spaced from the upper surface of the beam support member, so that there is open space between the wedge member and the bottom surfaces of beam supported by the upper surface of the beam support member.

Abstract: A fall protection apparatus includes a heavy support base with a pivotal mast having a top member for rotation around the axis of the mast carrying a series of booms pivotal about respective vertical axes, each having an end coupling member for receiving a fall restraint harness. Each boom is formed by a tube which fractures on a fall and an elongate stainless steel strap inside the tube which bends without fracturing. The mast includes a series of telescopic rectangular mast sections with a winch driven cable and pulley arrangement for extending the first section which acts to pull the second inner section to the extended position as the first inner section moves out of the outer section. Each section includes first and second pulleys mounted at the same face of the section with the cable located between the face of the section and the face of the next section.

Abstract: A fall protection apparatus includes a heavy support base with a pivotal mast having a top member for rotation around the axis of the mast carrying a series of booms pivotal about respective vertical axes, each having an end coupling member for receiving a fall restraint harness. Each boom is formed by a tube which fractures on a fall and an elongate stainless steel strap inside the tube which bends without fracturing. The mast includes a series of telescopic rectangular mast sections with a winch driven cable and pulley arrangement for extending the first section which acts to pull the second inner section to the extended position as the first inner section moves out of the outer section. Each section includes first and second pulleys mounted at the same face of the section with the cable located between the face of the section and the face of the next section.

Abstract: A system including: a seat post; a user interface operatively connected with the seat post, the user interface configured for receiving instructions associated with a height of the seat post and for communicating received instructions to at least one controller coupled with a motive source of the seat post; and a valve assembly in communication with the motive source, the valve assembly regulating fluid flow within a variable finite positioning seat post height mode in response to a translation of the received instructions by the motive source.

Abstract: A seat support with adjustment systems allowing a height and swivel adjustment functionality of the seat in a manner free of any wobble and shaking motion. The seat mechanism for height and swivel adjustments have screw adjustment applying a pre-load on a resilient component which gives a resilient force on a load bearing surface. The load bearing surface guides the seat part in motion during seat adjustment in a way to reduce friction and wear with use in time. The screw adjustment and the resilient component are configured such that play in guiding of the seat part in motion during seat adjustment is eliminated regardless of fabrication and component variations, and wear, with use in time. A screw adjustment locking device is configured to assure a stable adjustment with use in time.

Abstract: A support for supporting a structure on a surface, comprising at least one support element, each support element comprising a piston, a cylinder in which the piston is moveable, and a brake for maintaining the piston in a position that is stable relative to the cylinder, wherein the piston and the cylinder are arranged so that a loading associated with the structure effects an adjustment of the support element, and wherein an increase in hydraulic pressure within the cylinder, effected by the loading associated with the structure, activates the brake.

Abstract: An automatic balancing structure of a medical balancing stand has stoppers arranged on a turn plate. In a normal state, the stoppers are in contact with and hold a contact part of a lever so that the lever and turn plate follow a rotative motion of a lateral arm. If the lateral arm causes an imbalance, a strain occurs on the lever to which a strain sensor is attached. The strain sensor detects the strain and outputs a signal to an adjustment unit so as to cancel the imbalance of the lateral arm. The strain sensor helps downsizing the automatic balancing structure and making the balance adjustment easier.

Abstract: Embodiments include a balance mechanism having a first cam and a second cam configured to convert a variable force exerted by the energy storage member into a substantially constant force applied to a mounting portion. The balance mechanism may be useful for balancing forces such that a user can set the height of an electronic display and/or other equipment attached to the balance mechanism at a number of heights within the range of travel allowed by the mechanism. Lift mechanisms, display positioning apparatuses, and height adjustable desks incorporating a multi-cam balance mechanism are also provided. A method of positioning a display is also provided.

Abstract: Provided is a support apparatus including a support tube, a support column inserted in the support tube, and a rotational position return mechanism provided between the support tube and the support column to return the support column rotated relative to the support tube to a reference position in response to a reduction in rotational torque applied to one end of the support column.

Abstract: The present technology provides an extendable pillar having a lower section with a base column, and an upper section with an upper column. The base column includes a ratchet mechanism that operates with a fastener rod in the upper column. When the ratchet mechanism is in a locked position, the position of the upper section is fixed. When the ratchet mechanism is in an open position, the upper section can slide along the base column to extend or compress the length of the pillar. In certain embodiments, the upper column and the base column include friction connection mating components. The friction connection mating components cooperate to allow the upper section to slide along the base column when a sufficient force is applied to the upper section, while supporting the upper column at a fixed position when the force is removed.

Abstract: A panel supporting device with elevating function includes a supporting frame, a supporting sleeve, a guiding cover member, a driving block, a lead screw and a positioning liner. The supporting frame includes a plurality of guiding posts. The supporting sleeve is disposed between the guiding posts and connected to the panel. The guiding cover member fixedly covers an outside of the supporting sleeve and has a plurality of guiding holes in which the guiding posts penetrate. The driving block is fixed inside the supporting sleeve and has a screw hole and an inserting slot. The lead screw is accommodated inside the supporting sleeve and screwed in the screw hole. The positioning liner is accommodated inside the supporting sleeve and penetrates the inserting slot, thereby preventing the supporting sleeve from tilting or vibrating during up and down movement.

Abstract: Provided herein is a monopod or device for supporting a photographic instrument or accessory, such as a camera. The monopod or device comprises extendable members, e.g., an extendable mounting member with a mounting assembly and an extendable middle member with a threadably engagable, rotatable locking mechanism, a base member and an extension mechanism. The locking mechanism is configured to quickly lock the extendable members at an extended length or to collapse the same. The extension mechanism is disposed within the extendable and base members and secured independently to the same. This configuration enables a single smooth release with extending motion of the locking mechanism to telescopically extend or, conversely, collapse the extendable member portions of the monopod device.

Abstract: A multi-position adjustable height seat post comprises an inner tube, an outer tube, a locking assembly, a triggering device, a first extending element, and a second extending element disposed between the tubes. The locking assembly comprises an actuating unit, a plurality of parallel grooves located in the outer tube, a plurality of spherical detent elements located, in the grooves, and a plurality of spherical elements located in the inner tube. The triggering device connects to the actuating unit. The first extending element constantly pushes the to actuating unit moving in a first direction. The second extending element disposes between the tubes. Once the triggering device is triggered, the actuating unit moves in a second direction contrary to the first direction and makes the spherical elements to move inward laterally to let the inner tube and outer tube move relative to each other freely.

Abstract: Apparatus and methods for extending a retractable mast include engaging at least three flexible bands such that each band forms a side of a mast. Each band includes a right edge side and a left edge side, each edge having disposed thereon a set of spaced teeth, each tooth having a slot disposed therein and a tab disposed between adjacent teeth, the tab configured to engage the slot of an opposing tooth.

Abstract: A telescopic stand includes an outer tube, an inner tube, a chain, a housing, a driven member, a driving member, and a safety latch. The chain is secured on the inner tube. The housing is secured on the outer tube. The driven member is rotatably mounted in the housing and has a chainwheel and a worm gear. The chainwheel has engaging teeth meshing with the chain. The driving member is rotatably mounted in the housing and has a worm meshing with the worm gear. The safety latch is mounted on the housing and is movable to lock the driven member. Thus, when the inner tube bears a heavy load, the chainwheel co-operates with the chain to withstand the larger force applied by the inner tube and will not be worn or broken due to a larger rotation force.

Abstract: A support column with a vertical tube has a coaxially installed gas spring including a cylinder divided by a piston into first and second working chambers. A piston rod passes through the second working chamber in a sealed manner to the outside, where it is attached to a bottom support piece of the vertical tube. The cylinder projects out of the vertical tube and is guided with freedom to slide back and forth in a guide sleeve installed in the end of the vertical tube opposite the bottom support piece. A connection between the first and second working chambers can be blocked by a manually actuatable valve. A second valve between the chambers, which is closed when the gas spring is under load, can be switched to the open position after the load on the gas spring has been absent for a certain period of time.

Abstract: A lift for raising and lowering a backdrop is provided. The lift includes: a base including at least three legs; a tower boom extending substantially vertically from the base and including top, middle, and bottom telescoping sections, wherein the tower boom is capable of telescoping from a fully retracted position to a fully extended position; and a post extending substantially vertically from the tower boom, wherein the post is detachable from the tower boom at a lower end of the post and attachable to a truss adapted for attaching to a backdrop at an upper end of the post, wherein a minimum height of the tower boom in the fully retracted position is less than about 35% of a maximum height of the tower boom and post, when the tower boom is in the fully extended position.

Abstract: A height adjustable column, comprising an inner column, an intermediate column having a lower side, an outer column having a lower side, a lifting mechanism having at least a twofold transmission, and a linear actuator. The height adjustable column effects height adjustment by sliding the columns into each other and apart from each other. The linear actuator is dimensioned and arranged such that it protrudes beyond the lower side of the outer column in a state in which the columns are slid into each other.

Abstract: A lifting column for treatment tables, hospital- and care beds with a casing consisting of three telescopic members (11, 12, 13) with a drive unit located in the hollow of the intermediate member (12). The drive unit comprises a body element (22) with chain wheels (25, 33) and one chain (47) provided with driving rods (50, 51) secured to the two other telescopic members (11, 13). The drive unit further comprises a linear actuator (18) with an electric motor (19), which drives a spindle (21) located within the cross section of the body element (22) and a spindle nut (28) secured thereto for longitudinal displacement of the body element (22) with the chain wheels (25, 33), so that the telescopic members (11, 12, 13) are extended or retracted depending on the direction of rotation of the motor. Thus a compact structure is achieved as the guide is constructed as a casing and the actuator is integral with the body element which has one chain only.

Abstract: A support for supporting a structure on a surface, comprising at least one support element, each support element comprising a piston, a cylinder in which the piston is moveable, and a brake for maintaining the piston in a position that is stable relative to the cylinder, wherein the piston and the cylinder are arranged so that a loading associated with the structure effects an adjustment of the support element, and wherein an increase in hydraulic pressure within the cylinder, effected by the loading associated with the structure, activates the brake.

Abstract: A telescoping mast able to efficiently extend and retract multiple telescoping sections without jar and minimal energy. The telescoping mast has multiple telescoping sections, a position feedback sensor, a motor, a spring motor, and a computation unit. The position feedback sensor is coupled to at least one telescoping section and configured to identify a position of the telescoping sections. The motor is also coupled to the telescoping sections, and raises and lowers the telescoping sections. The computation unit controls the motor based on the position of the telescoping sections.

Abstract: A vertical linear actuator mechanism for positioning a load at a desired elevation above a support surface. A vertical linear actuator is comprised by a pair of gas spring cylinders interconnected together and secured inside a telescopic pedestal and extends and retracts the pedestal. An actuable lock mechanism is engageable with connecting bars associated with a respective one of the gas spring cylinders and immovably connects the connecting bars to position the load at a desirable elevation above the support surface.

Abstract: A heavy equipment support stand is provided have a piston therein for air pressure assisted raising and lowering of the support and having an insert support pin guide connected to the stand to direct the movement of a support pin into and out of the stand.

Abstract: A vertically adjustable item of furniture with a vertical pipe, a supporting base arranged at a first end of the vertical pipe, a guide bush fastened to a second end of the vertical pipe opposite to the supporting base, a cylinder which is arranged coaxially in the vertical pipe a piston which divides the cylinder into a first work chamber and a second work chamber, a piston rod fastened by its first end to the piston extends through the second work chamber and a connection between the first work chamber and the second work chamber which can be blocked by a valve actuatable by an actuating device. The valve is controllable electromagnetically. The furniture item comprises a sensor or switch which generates a signal causing the valve to close when the piston reaches a position in the cylinder near the valve.

Abstract: A supporting bracket has a base and a positioning column. The base is mounted on a bottom bracket to form a stand. The positioning column is attached to base and has a first positioning piece and a second positioning piece. The first positioning piece us formed on the base and has a first inclined surface and an inclined slot. The second positioning piece is mounted slidably on the first positioning piece and has a second inclined surface and a slide mounted slidably in the inclined slot. Sliding the second positioning piece on the first positioning piece changes an outer diameter of the positioning column so that the positioning column may be fitted into mounting holes of different devices such as audio speakers.

Abstract: An elevating mechanism includes a sleeve having a first end and a second end, and an elevating component installed inside the sleeve and having a third end and a fourth end. When the elevating component is located in a first position relative to the sleeve, a main spring is compressed by the elevating component at a first deformation. When the component is located in a second position relative to the sleeve, the main spring is compressed by the elevating component at a second deformation. The first deformation is greater than the second deformation. When the elevating component is located in the first position relative to the sleeve, a complementary spring is compressed at a third deformation. When the component is located in the second position relative to the sleeve, the complementary spring is compressed at a fourth deformation. The third deformation is greater than the fourth deformation.

Abstract: An adjustable apparatus includes a bracket, an extendable member, a moving member, and a display supporting mount. The extendable member includes a base portion and a resilient tape portion attached to the base portion. The tape portion is secured to the bracket. The moving member is attached on the base portion. The display supporting mount is secured to the moving member for being secured to a display device, and movable with the moving member.

Abstract: An apparatus for fitting a bicycle saddle comprises a mounting rod secured to a bicycle frame, a height adjuster mounted upon the mounting rod, a lateral adjuster mounted upon the height adjuster, a tilt orientation adjuster mounted upon the lateral adjuster, and a clamp securing the saddle to the tilt orientation adjuster.

Abstract: A lift apparatus for supporting a C-arm or a U-arm of an X-ray machine is provided. The lift apparatus includes an outer shell and an inner shell disposed within the outer shell and configured to slide upward and downward within the outer shell. The C-arm or U-arm is connected to the inner shell. A gas spring is disposed within the inner shell. A first end of the gas spring is connected to a top of the inner shell, and a second end of the gas spring is connected to a bottom of the outer shell through a bottom of the inner shell. Upward and downward movement of the inner shell is driven by expansion and compression of the gas spring.

Abstract: A telescopic support is disclosed and has outer and inner leg parts. The outer leg part has: a tubular body defining a longitudinal axis and having an interior passage through which the axis extends centrally. The inner leg part has: a shuttle body part disposed at least partially in the tubular body; and rollers rotably mounted to the shuttle body to support the inner leg part for longitudinal reciprocating movement in the tubular body. The support can be secured to a base and topped with a work-surface defining member to form a height-adjustable table, as also disclosed.

Abstract: A height adjustable seatpost assembly is provided with first and second tubes, a ratchet mechanism and a drive source. The first and second tubes are telescopically arranged. The ratchet mechanism includes a ratchet tooth structure and a pawl structure. The pawl structure is engaged with the ratchet tooth structure in a lock position. The pawl structure is movably coupled with respect to the ratchet tooth structure in a movable position such that the first and second tubes are movably arranged relative to each other in at least one axial direction of the first and second tubes. The drive source moves the pawl structure between the lock position and the movable position in response to operation of the drive source. The drive source further axially moves the first and second tubes relative to each other in response to operation of the drive source.

Abstract: A vertical linear actuator mechanism for positioning a load at a desired elevation above a support surface is described. The vertical linear actuator mechanism in one aspect thereof comprises an electric motor having a drivable shaft. The drivable shaft is coupled to a linear extendable mechanism having a load connector at a top end thereof. A potentiometer detects the position of the load connector relative to the support surface and provides position signals to a motor controller circuit which monitors the position of the load connector and controls the operation of the electric motor. In another aspect thereof the vertical linear actuator is comprised by a pair of gas spring cylinders interconnected together. The vertical linear actuator mechanism is secured inside a telescopic pedestal and extends and retracts the pedestal.

Abstract: A telescopic lifting column for height adjustment of elevatable tables (1) consists of a stationary rectangular profile (2), which at the bottom rests against a floor, and of a sliding quadrangular profile (3), which slides inside the stationary profile (2) and which can be activated up or down by a linear actuator (4) and which at the top rests against a table top (7). The profiles (2, 3) each have an open side (resp. 8 and 9), and the linear actuator is embodied as a toothed rack (10), which is fastened to the internal side (3?) of the sliding profile (3) opposite the open side (9), and which is in mesh with a toothed wheel (11), which is coupled to a gear motor (12,13), which is fastened to the stationary profile (2) of the lifting column. On the side facing the open side (9), the toothed rack (10) is embodied with a guide way (18) with a width (a) in which two guide pins (19, 20)—with a mutual distance (b) and fastened to the stationary profile (2)—are in mesh.

Abstract: An adjustable stand to be detachably connected to and provide vertical support for a conventional water meter of the kind that is coupled to a fire hydrant to measure the volume of water consumed by a user by way of the fire hydrant. The water meter stand includes a foot that lays upon the ground and a meter support plate that is attached to the fire hydrant water meter. A turnbuckle assembly is located between the foot and the meter support plate. A housing of the turnbuckle assembly is rotated to cause upper and lower threaded rods to correspondingly move through the housing. Accordingly, the length of the stand between the foot and the meter support plate can be selectively adjusted regardless of the dimensions of the fire hydrant and the elevation of the water meter coupled thereto and suspended above the ground.

Abstract: A cart for use with an ultrasonic imaging apparatus, comprising: a supporting part, a cart body and a bottom part; said cart body is connected to the supporting part and the bottom part; said supporting part is provided with an interface thereon for supporting and connecting the ultrasonic imaging apparatus; said cart body is an elevator structure provided with a power cable therein for supplying power to the ultrasonic imaging apparatus; the lower portion of the supporting part and the upper portion of the bottom part are both provided with a power socket; said power cable is a coiled cord structure, and its two ends are connected to the two power sockets; a stretchable elastic component having elastic recovery is provided inside the coiled cord structure of the power cable.

Abstract: A household lift is provided with a stationary base and rack, wherein the movement of the drive gears and an associated movable portion is supported for linear motion parallel to the rack by at least a pair of extensible slides that are oriented at approximately right angles to one another.

Abstract: A ball chair may comprise a chair frame, a ball body and an adjusting unit. The chair frame has a connecting base and a legs base, and a supporting column formed therebetween is configured to achieve a telescopic action thereby adjusting a height of the ball chair. The connecting base is formed in a concave shape to form a housing space therein, and an annular frame is formed at an upper end of the connecting base. The ball body is configured to be coupled on the connecting base of the chair frame, and the annular frame is configured to couple with an outer periphery of the ball body thereby limiting a position thereof. As a result, the ball chair is suitable for different statures of users and enables the users to sit thereon for training or rehabilitation.