Abstract: A castor includes a main body, two rollers, a plurality of rolls, two retaining members, and two covers. Thus, the rolls are rotatably mounted between the main body and the respective roller, so that each of the rollers is rotatable on the main body smoothly. In addition, the rolls and the rollers are made of the same material to reduce the friction between the rolls and the rollers during rotation of the castor, so that the rolls and the rollers are not easily worn out during a long-term utilization. Further, the rollers are covered by the covers so that only the through hole of the main body is exposed outwardly from the covers and the rollers, thereby enhancing the aesthetic quality of the castor.

Abstract: An armrest of a chair includes a fixing board, a first movable board, two limit plates, a second movable board, a positioning body, a restoring spring, a lining, a foam body, a push button, a bottom cap, and two shading plates. Thus, the horizontal position of the armrest is adjustable in a two-dimensional way, so that the horizontal position of the armrest is adjusted freely and optimally according to a user's practical requirement, thereby providing a comfortable sensation to the user. In addition, the horizontal position of the armrest is adjustable by pressing the push button, so that the horizontal position of the armrest is adjusted easily and quickly, thereby facilitating the user adjusting the horizontal position of the armrest.

Abstract: An armrest includes an armrest support having a locking seat formed with a plurality of locking grooves, a sliding seat movably mounted on the locking seat, and a push button movably mounted on the sliding seat and having a first end formed with a locking portion detachably locked in one of the locking grooves and a second end formed with a push portion. Thus, the locking portion of the push button is detached from the respective locking groove of the locking seat when the sliding seat is movable relative to the locking seat so that the sliding seat will not rub the locking seat during movement of the sliding seat, thereby preventing from producing a noise during adjustment of the armrest.

Abstract: An armrest assembly for a chair includes an armrest support, a slide seat mounted on the armrest support, a first slide mounted on the slide seat, a second slide mounted on the first slide, a rotation member mounted on the second slide, a retainer mounted on the rotation member, a mounting member secured in the armrest support and provided with a stud extended through the first slide, the second slide and the rotation member and secured to the retainer, and an armrest mounted on the first slide. Thus, the armrest is movable in the axial direction and the transverse direction and is rotatable horizontally relative to the armrest support, so that the position of the armrest can be adjusted easily and freely according to the user's practical requirement.

Abstract: A castor includes a main body, two rollers each rotatably mounted on the main body, a stop member movable in the main body between a first position where the stop member is located at a height higher than that of each of the two rollers and a second position where the stop member is located at a height lower than that of each of the two rollers, a slide slidably mounted in the main body to move the stop member, and a control member pivotally mounted on the main body to move the slide. Thus, when the stop member is movable downward to rest on the ground, the two rollers are suspended in the air, so that the castor is locked exactly without slipping or moving on the ground.

Abstract: A chair includes a leg having a mounting hole, a castor having an end portion provided with an axle mounted in the mounting hole of the leg, and a substantially S-shaped snap ring mounted in the annular groove of the axle and rested on a peripheral wall of the mounting hole of the leg. Thus, the S-shaped snap ring is enclosed around the peripheral wall of the annular groove of the axle and rested between the upper wall and the lower wall of the annular groove, so that the S-shaped snap ring will not slip in the annular groove of the axle to prevent from producing noise due to friction between the axle of the castor and the leg during movement of the castor.

Abstract: An armrest assembly includes an L-shaped support having a vertical section, a lift mechanism telescopically mounted in the vertical section of the support, a sleeve movably mounted on the vertical section of the support and secured on the lift mechanism to move therewith, and an armrest secured on the lift mechanism to move therewith. Thus, the armrest can be moved on the vertical section of the support upward and downward adjust the height of the armrest so as to fit requirements of different users. In addition, the user only needs to drive the control member to release the movable shaft from the limit plate so as to adjust the height of the armrest easily and conveniently, thereby facilitating the user adjusting the height of the armrest.

Abstract: An office chair armrest includes a support rod, a base, a locating seat, a mounting seat and an upper cover, wherein the base has a chamber having at least one guide rail each provided with engagement grooves; the locating seat has a recess having engagement grooves and at least one engagement block for engaging in on of the engagement grooves of the base by means of resilience of a spring; the mounting seat has at least one engagement block for engaging in one of the engagement grooves of the locating seat by means of resilience of a spring, thereby enabling the office chair armrest to be adjusted to move forward, backward, leftward or rightward by a user himself according to his own need to be in a proper position or at a proper angle that is comfortable for his arm to be rested on.

Abstract: An office chair armrest includes a support rod, a base, a locating seat, a mounting seat and an upper cover, wherein the base has a chamber having at least one guide rail each provided with engagement grooves; the locating seat has a recess having engagement grooves and at least one engagement block for engaging in on of the engagement grooves of the base by means of resilience of a spring; the mounting seat has at least one engagement block for engaging in one of the engagement grooves of the locating seat by means of resilience of a spring, thereby enabling the office chair armrest to be adjusted to move forward, backward, leftward or rightward by a user himself according to his own need to be in a proper position or at a proper angle that is comfortable for his arm to be rested on.

Abstract: An office chair caster has a wheel holder, a wheel body, a spindle seat and a spindle. Make a first base and a second base oppositely joined together to form the wheel holder with retaining pieces of the second base inserted into fitting slots of the first base, and make the spindle seat that is extended through by the spindle inserted into through holes of the first and second bases with engagement protuberances of the spindle seat aligned with engagement grooves of the second base. The spindle seat can be rotated at 90 degree to make the engagement protuberances impelled over projections of the first base, stopped by stop blocks of the first base, engaged in sliding slots of the second base, and limited between the projections and the stop blocks without moving, thereby the spindle seat can be firmly fixed in the wheel holder to hold the spindle securely.

Abstract: An office chair castor includes a base, two castor bodies, two beads bases, and two set of beads. The beads of the two sets of beads positioned in portion grooves of the two beads bases are also rotatably positioned in both the grooves of the two projecting annular walls of the base and the grooves of the two castor bodies, permitting the mutual contact dimension of the base and the two castor bodies become small to cause small friction, which may produce little noise and may let the castor bodies not to be stuck but rotate smoothly.

Abstract: An office chair caster with a structural improvement in the invention mainly has a wheel holder, a wheel and a wheel axle. Extend the wheel axle through a through hole of the wheel, and then place the wheel in an open slot of the wheel holder to make both ends of the wheel axle respectively slide upwards from lower ends of two slide ways of two clamp plates of the wheel holder and further upwards along two inclined planes of the two slide ways so as to be inserted into two recesses of the two clamp plates with two ring grooves of the wheel axle respectively engaged with two circumferential ridges of the two recesses, thus provide a quick and secure assemblage to the office chair caster without worry of coming loose after a long-termed use.

Abstract: A chair caster in the invention mainly includes a wheel holder, a spindle, a wheel axle, two wheel bodies, two shake-proof washers and two caps. Each of the two wheel bodies is provided with a recessed chamber disposed in an inner side thereof and capable of being fitted with a shake-proof washer made of a soft rubber material, thereby enabling the chair caster to lower shaking and noise in rolling under the resilience of the shake-proof washers and providing better strength to the whole structure of the chair caster so as to prolong the working life.

Abstract: A chair caster in the invention mainly includes a wheel holder, a spindle, a wheel axle, two wheel bodies, two shake-proof washers and two caps. Each of the two wheel bodies is provided with a recessed chamber disposed in an inner side thereof and capable of being fitted with a shake-proof washer made of a soft rubber material, thereby enabling the chair caster to lower shaking and noise in rolling under the resilience of the shake-proof washers and providing better strength to the whole structure of the chair caster so as to prolong the working life.

Abstract: A chair caster with an immovable function in the invention mainly includes a wheel holder, a spring, a sleeve, a spindle, and a non-slip pad. When a user sits on a chair, the spindle is capable of being lowered by the weight of a user with an annular flange of the spindle pressed against the sleeve to lower the sleeve to compress the spring with both ends of the spring respectively pressed against a bottom of the sleeve and a stop end of the wheel holder so that the non-slip pad engaged at a lower portion of the spindle follows downward movement of the spindle to be affixed to the ground, thereby enabling the chair to remain immovable in a certain location without worry of displacing the chair to make the user suffered a fall and thus wounded.

Abstract: A chair arm in the invention includes an arm body having a base provided with two recesses in two opposite sidewalls of the base, a mounting seat having a stop plate provided with a raised face at one sidewall of the stop plate and corresponding to one of the recesses, and a cover. The raised face can be fitted into one of the recesses and firmly screwed with the base by screw members. After the cover is closed on the other sidewall of the base, a left or right chair arm of the invention is assembled together and can be fixed at a left or right side of a chair seat by having the other side of the mounting seat fastened at the chair seat. Therefore, only one mold is adapted for the left and right chair arms, thereby reducing the costs in producing two molds and providing easy assemblage.