Adjustment device for a chair with rocking mechanism

The device according to one or more of the preceding claims, characterized in that one end of said first cable (12) is connected to the free end of said first wing (15) so that a traction imposed on said first cable (12) is followed by a rotation of said lever (13) so as to make the terminal end of said second wing (16) interact with said central gas-operated post (7), so as to activate the height adjustment of said seat, a tab (18) protruding radially to said second wing (16) and interacting with a second spring (19) which is interposed between said tab (18) and said, underlying, first base (3) of said first plate (2), said second spring (19) allowing the return to a neutral position of said lever (13) once said first cable (12) has been released so as to not activate said central gas-operated post (7).

The device according to one or more of the preceding claims, characterized in that said second cable (20) is slideably associated with a side of the front part of said first plate (2) which lies opposite the side for inserting said first cable (12), said second cable being adapted to activate said mechanism (21) which allows or prevents the rocking of said second plate (10), said second cable (20) being guided inside said first plate (2) so that its terminal end (22) arranges itself proximate to the bottom of a first cavity (23) which is provided inside and longitudinally to said first plate (2), on a side thereof which lies opposite the entry side of said first cable (12).

The device according to one or more of the preceding claims, characterized in that said mechanism (21) is constituted by a slider that has a substantially S-shaped plan configuration so as to define a first arm (24) which is shaped like a parallelepiped and is accommodated inside said first cavity (23) with the possibility to slide axially with respect to said first cavity (23) in contrast with a third spring (25) which is interposed between the vertical rear wall (26) of said first arm (24) and a facing wall (27) of a block (28) which is associated internally with said first plate (2) in front of said first cavity (23), a bridge (29) being connected to the upper end of said first arm (24) and being arranged along an axis that is inclined with respect to the longitudinal axis of said first plate (2).

The device according to one or more of the preceding claims, characterized in that a second arm (30) is connected in a lower region to the terminal end of said bridge (29), which lies substantially at the longitudinal central axis of said first plate (2), said second arm being parallelepiped-shaped, having a substantially T-shaped plan configuration, and being accommodated inside a second cavity (31) which is provided in the rear region of said first plate (2) where said first springs (11a, lib) also are arranged, said second arm (30), which slides freely and axially with respect to said second cavity (31) along an axis that is longitudinal to said first plate (2), having a first shank (32), with a rectangular plan shape, which is arranged in the interspace between said first springs (11a, 11b), and the lower surface (33) of which is arranged on a plane that lies lower than the plane of arrangement of said bridge (29), the axial movement of said second arm (30) being guided, since said arm lies between a pair of shoulders (34a, 34b) which are mutually parallel and protrude at right angles to said second cavity (31), and the longitudinal extension of each shoulder of said pair of shoulders (34a, 34b) being substantially equal to the length of said shank (32).

The device according to one or more of the preceding claims, characterized in that a first head (35) is connected to said first shank (32) and has a rectangular plan shape with dimensions such that its third wings (36a, 36b) protrude laterally beyond the space occupation of said pair of shoulders (34a, 34b) so as to determine the point of maximum retraction of said first head (35), and therefore of said mechanism (21), within said second cavity (31), in this condition an empty space (37) being defined, between the terminal end of said first head (35) and the bottom wall (38) of said second cavity (31), which constitutes a temporary seat for a tooth (39) which protrudes internally and downward with respect to said second plate (10) and allows said second plate (10) to rock with respect to said first plate (2).

The device according to one or more of the preceding claims, characterized in that said first shank (32) and said first head (35) interact with adapted guides, such as a T-shaped bar (40) the second head (41) of which is arranged transversely so as to connect the upper terminal ends of said pair of shoulders (34a, 34b) which are directed opposite with respect to said bridge (29), said second head (41) lying above said, underlying, upper surface (33) of said first shank (32), said bar (40) having a second shank (42) which arranges itself along the longitudinal axis of said first plate (2) in the direction of said bottom wall (38) and surmounts, in the free-rocking condition for said second plate (10), the entire thickness of said first head (35).

The device according to one or more of the preceding claims, characterized in that an additional guide for the sliding of said first shank (32) and said first head (35) is provided by the presence of a longitudinal ridge (43) which protrudes from the bottom of said second cavity (31) and is accommodated inside a complementarily-shaped seat (44) which is provided below said first shank (32) and optionally also below said first head (35), said third spring (25) pushing said mechanism (21), bringing said second head (35) adjacent to said bottom wall (38) of said second cavity (31), thus preventing the rocking of said second plate (10).

The device according to one or more of the preceding claims, characterized in that the activation of said second cable (20) causes the retraction of said mechanism (21) until said second head (35) is brought into abutment against the end of said pair of shoulders (34a, 34b), thus freeing up the empty space (37) in order to temporarily accommodate said tooth (39) thereat.