A clamp for fastening a trackball-containing shell to a keyboard, comprising:
- a base comprising (a) a plate comprising first, second, third and fourth edges, upper and lower surfaces, two first threaded holes formed through said upper surface thereof, two second threaded holes formed in said lower surface thereof and a cutout formed therein between said first threaded holes and between said second threaded holes, (b) two walls formed along said second and fourth edges of said plate thereof, (c) a wall formed along said third edge of said plate thereof, said walls formed along said second and fourth edges of said plate thereof respectively comprising two limits formed thereon facing each other and (d) a tray formed on said wall formed along said third edge of said plate thereof for carrying the trackball-containing shell;
- a first clamping element comprising a first jaw perpendicularly connecting therewith, two holes formed therein and an opening formed therein between said holes, said first clamping element being sited on said plate of said base;
- a button comprising upper and lower surfaces and a pushing portion formed on said lower surface thereof, said button being sited on said first clamping element with said pushing portion inserted through said opening formed in said first clamping element and said cutout formed in said plate of said base;
- a top plate comprising two holes formed therein, said top plate being sited on said button;
- two threaded bolts inserted through said holes formed in said top plate and said first clamping element for being engaged in said first threaded holes so that said first clamping element is attached to said base and that said button is mounted between said first clamping element and said top plate;
- a second clamping element comprising first, second, third and fourth edges, upper and lower surfaces, a second jaw perpendicularly formed along said first edge thereof and two anchors formed along said third edge thereof, said second clamping element being sited below said plate of said base between said walls formed along said second and fourth edges of said plate of said base;
- a spring comprising a middle section and two terminal sections, said middle section of said spring being sited against said third edges of said plate of said base and said terminal sections of said spring being sited against said wall formed along said third edge of said plate of said base so that said second jaw is biased toward said first jaw by means of said spring;
- a bottom plate comprising two holes formed therein, said bottom plate being sited below said second clamping element;
- and
- two threaded bolts being inserted through said holes formed in said bottom plate for being engaged in said second threaded holes.