Abstract: An adjusting mechanism is provided for selectively setting a restoring force acting on a backrest of a chair. In a biasing unit of the adjusting mechanism, a spring segment is disposed between a head end and a follower end to bias the follower end to the remote position. The follower end is angularly movable on a cam surface between distal and proximate positions. In response to movement of a backrest of the chair from a normal position to an inclined position to permit the follower end to be forced by the cam surface to move from the remote position to a close position, two different restoring forces can be set by adjusting the follower end between the distal and proximate positions.

Abstract: A paper punch includes a plurality of punch seats movably disposed along a slide board mounted on a base, a press board pivotably connected to the base to press punch heads of the punch seats, and a plurality of control members respectively disposed on the punch seats and operable to releasably lock the punch seats on the base. Each punch seat has a force transmitting member movably disposed on a die holder to transmit a pressing force of the press board so as to press the punch head downwardly to perform a firm and stable punching operation.

Abstract: An adjusting mechanism is provided for selectively setting a restoring force acting on a backrest of a chair. In a biasing unit of the adjusting mechanism, a spring segment is disposed between a head end and a follower end to bias the follower end to the remote position. The follower end is angularly movable on a cam surface between distal and proximate positions. In response to movement of a backrest of the chair from a normal position to an inclined position to permit the follower end to be forced by the cam surface to move from the remote position to a close position, two different restoring forces can be set by adjusting the follower end between the distal and proximate positions.

Abstract: An armrest assembly includes a mounting plate disposed on a support column and having an elongated moving slot for a first pivot shaft to movably extend therethrough, an armrest plate having a sliding slot elongated transverse to the moving slot such that the first and second pivot shafts extend through and are slidable along the sliding slot to allow the armrest plate to be horizontally movable and turnable relative to the mounting plate, and a retaining unit disposed to produce a magnetically attractive force that generates resistance against a relative movement of the armrest plate to the mounting plate.

Abstract: A paper punch includes a base and a slide board is connected to the base. Multiple punch seats are located on the slide board and above the hole of the base. Each punch seat has a control member and a connection arm connected to the slide board. The control member is pivotably connected to the connection arm. The control member has an eccentric seat and an operation board. The eccentric seat is a cam and eccentrically connected to the connection arm. A first face is defined in the eccentric seat and located in opposite to the operation board. A second face is located adjacent to the first face. When switching the first face to the second face, the punch seat is movable along the slide board so as to obtain a desired distance between the punch seats.