Adjustable keyboard supporting mechanism

Claim 1

A mechanism for mounting a keyboard for movement relative to a horizontal support, said mechanism comprising: a pair of slide devices defined by first parts having means for fixing same to depend from a lower surface of said support and second parts supported by said first parts for horizontally directed reciprocating movements between keyboard storage and use position, said first parts are horizontally elongated guide channels having downwardly opening guide slots bounded by pairs of aligned guide flanges, said second parts are defined by followers slidably supported one by each of said guide tracks and mounting brackets carried one on each of said followers, said followers have a generally T-shaped sectional configuration with head portions thereof slidably supported within said guide channels by said guide flanges and with depending portions thereof depending downwardly through said guide slots, said mounting brackets are of L-shaped cross-sectional configurations having upstanding plate portions fixed to said depending portions and defining an upper aperture and a lower aperture and horizontally extending plate portions arranged in a facing relationship and shaped to define mounting hooks; support means for supporting said keyboard, said support means includes a pair of support brackets each having an upper aperture and a lower aperture, at least one of said support brackets having an arcuate slot disposed concentrically of said lower aperture thereof, said support brackets are associated one with each of said mounting brackets, said support brackets are of L-shaped cross-sectional configuration having upstanding plate portions defining said upper and lower apertures of said support brackets and horizontally extending plate portions arranged in a facing relationship; link means for supporting said support means on said second parts for vertically directed movements between upper and lower keyboard use positions relative to an intermediate position in which said support means and said keyboard may be stored closely adjacent said lower surface to provide a thin vertical profile for said mechanism and said keyboard when said second parts are disposed in said keyboard storage position, said link means includes two pairs of upper and lower links with first and second ends of the upper and lower links of each pair pivotally supported relative to said upper and lower apertures of associated ones of said mounting and support brackets, respectively, at least one of said lower links carrying a member slidably received within said arcuate slot for engagement with opposite ends thereof to define said upper and lower keyboard use positions, said member having a free end thereof threaded to adjustably support a clamping device cooperating with said one of said lower links to releasably clamp said one of said support brackets therebetween and thereby releasably lock said support means in any use position throughout the range of its movement between said upper and lower keyboard use positions, said upper links lie adjacent oppositely facing surfaces of said upstanding plate portions of said mounting and support brackets in vertical alignment with said guide slots, said lower links lie adjacent facing surfaces of said upstanding plate portions of said mounting and support brackets and are shaped to define mounting hooks; and spring means coupling said mounting brackets to said lower links to at least partially counterbalance the weight of said support means and keyboard supported thereon, said spring means comprise a pair of spring devices having opposite ends thereof fixed to said mounting hooks of said mounting brackets and said lower links, said first ends of said lower links are coupled transversely of said mechanism by a torsion member, and said upper links have cam surfaces shaped and arranged to engage interiorly of said guide channels for moving said support means into said intermediate position from said upper use position incident to movement of said second parts towards said keyboard storage position.