mechanism for adjusting the pre-load of a stiffening spring for seats

Abstract

Mechanism for regulating the preload of at least a stiffening spring ( 3 ) for a revolving element ( 2 ) with respect to at least a support frame ( 1 ) of a seating device, of the type comprising a mobile striker ( 7 ) for one end of said at least one spring ( 3 ), connected to said revolving element ( 2 ), and a regulating cursor ( 6, 10 ), onto which the other end of said at least one spring ( 3 ) rests, said regulating cursor ( 6, 10 ) being conceived to slide along a rod-shaped guide element ( 4 ), characterised in that said rod-shaped guide element ( 4 ) is connected, at one end thereof, in a sliding manner, to said mobile striker ( 7 ), and it is also integrally fixed to said support frame ( 1 ).

1 . Mechanism for regulating the preload of at least one stiffening spring for a revolving element with respect to at least a support frame of a seating device, of the type comprising a mobile striker for one end of said at least one spring, connected to said revolving element, and a regulating cursor onto which the other end of said at least one spring rests, said regulating cursor being sliding along a rod-shaped guide element, wherein said rod-shaped guide element is constrained, at one of its ends, in a sliding manner to said mobile striker, and it is also integrally fixed to said support frame. 
     
     
         2 . Mechanism according to  claim 1 , wherein said regulating cursor comprises a mobile head and a resting element for said end of said at least one spring, said mobile head and said resting element being constrained, at least in a sliding manner, to said rod-shaped guide element. 
     
     
         3 . Mechanism according to  claim 2 , wherein said mobile head is constrained to said guide rod by means of a threaded type coupling. 
     
     
         4 . Mechanism according to  claim 2 , wherein said resting element is constrained to said guide rod such a way to be free to slide thereon. 
     
     
         5 . Mechanism according to  claim 1 , wherein said guide rod is fixed to said support frame at, or near, the end of said guide rod not engaged with said mobile striker. 
     
     
         6 . Mechanism according to  claim 1 , comprising at least one manual actuation device kinetically connected to a drive shaft, which rotates around its own axis, said manual actuation device being linked to said support frame, wherein it comprises means to transform the rotating motion of the drive shaft of said manual actuation into an at least a transversal motion of said regulating cursor along said rod-shaped guide element. 
     
     
         7 . Mechanism according to  claim 6 , wherein said drive shaft and said regulating cursor are incident with respect to one another. 
     
     
         8 . Mechanism according to  claim 6 , wherein said regulating cursor comprises a mobile head externally provided with grooves that are substantially helical, and said drive shaft comprises a worm screw, said head having grooves that are substantially helical and said worm screw also belonging to said means for transforming the rotary motion. 
     
     
         9 . Mechanism according to  claim 6 , wherein said means for transforming the rotary motion of said drive shaft comprise a cogged pinion that engages with a relative rack. 
     
     
         10 . Mechanism according to  claim 1 , wherein said mobile striker engages with said rod-shaped guide element in a telescopic manner. 
     
     
         11 . Mechanism according to  claim 10 , wherein said mobile striker comprises, or is integral, to a sleeve, inside which said rod-shaped guide element is engaged. 
     
     
         12 . Mechanism according to  claim 11 , wherein said sleeve is pivoted in a direction transversal to the axis of said rod-shaped guide element, on said mobile element. 
     
     
         13 . Mechanism according to  claim 1 , wherein said spring is a torsion cylinder helical spiral spring. 
     
     
         14 . Mechanism according to  claim 13 , wherein said cylindrical spring is mounted in a substantially co-axial manner on said rod-shaped guide element. 
     
     
         15 . Mechanism according to  claim 1 , wherein said revolving element is the backrest frame of a seating device and said support frame is the seating frame and/or the base of said seating device. 
     
     
         16 . Mechanism according to  claim 1 , wherein said seating device is an office chair.