Flat file cabinet with drawer interlock

A flat file cabinet with an interlocking mechanism, comprising:

• (a) a frame having upper and lower frame bearings affixed adjacent a front thereof and having upper and lower horizontally-disposed frame channels with substantially parallel, spaced-apart upper and lower portions extending inwardly from said frame;
• (b) an upper drawer and a lower drawer slidably supported by said frame, each drawer having:
• (i) a drawer bearing affixed to a rearward end thereof, said drawer bearing being configured and located to travel within said frame channel when said drawer is moved relative to said frame;
• (ii) a horizontally disposed drawer channel, said drawer channel being configured to travel over said frame bearing when said drawer is moved relative to said frame;
• and
• (iii) a horizontally disposed interlocking channel extending outwardly from a side of said drawer, said interlock channel having a tapered forward end;
• (d) said interlocking channel of said lower drawer having a rearward end which is tapered;
• (e) said upper and lower interlocking channels being configured to travel between said upper and lower portions of said upper and lower frame channels, respectively,
• (e) a locking bar slidably supported by said frame, said locking bar having an inwardly-extending roller means and an inwardly-extending pin means located above said roller means;
• (f) a face plate fixedly attached to said frame, said face plate being located between said locking bar and said drawers and having an upper and lower elongated slot therein, said roller means extending through said lower slot and said pin means extending through said upper slot, said slots being configured to provided a predetermined amount of vertical travel for said locking bar;
• (g) said locking bar having a rest position in which said roller means and said pin means are in contact with a bottom of said respective slots, and having a displaced position in which said roller means and said pin means are in contact with a top of said respective slots;
• (h) when said locking bar is in said rest position, a first distance being the difference between a height of a lowest portion of said roller means and a height of an upper surface of said interlocking channel of said lower drawer, and a second distance being the difference between a height of a highest portion of said pin means and a height of a lower surface of said interlocking channel of said upper drawer;
• (i) when only said lower drawer is partially withdrawn, said interlocking channel of said lower bar being configured to urge said roller means, and thereby said locking bar and said pin means, upward into said displaced position;
• (j) when in said displaced position, said highest portion of said pin means being in an interference position above a height of said lower surface of said interlocking channel of said upper drawer to prevent forward movement of said upper drawer;
• (k) said first distance being greater than said second distance to prevent the forward movement of said lower drawer when only said upper drawer is partially withdrawn;
• and
• (l) said upper and lower drawers being removable from said frame, and said tapered rearward portion of said interlocking channel of said lower drawer being adapted to urge said roller means into said displaced position when said lower drawer is being replaced.