Clamping device for joining boards

A clamping device for joining together panel members lying substantially in the same plane with edges in abutting relationship but partially spaced by recesses providing a clearance therebetween and terminating into slots extending along said plane, said members having grooves on their undersides from said edges, comprising:

• a tensioning member extending along said edges and into said slots;
• securing members, each having an inner upstanding side bearing against said underside of said panel members near said recesses thereof on either side of said tensioning member;
• said securing members having an outer side terminating in flanges bent to provide engagement with said grooves;
• a generally trough-shaped, horizontal rail member bearing against said securing members;
• and
• screw means fitting in said rail member and passing through said clearance for urging said rail member against said securing members thereby driving said securing members toward each other until said edges of panel members are in tight abutment.