Abstract: A device for connecting inner boards of a multi-layer board includes a plurality of conduction pieces such as copper rings on each inner board and a plurality of prepregs are located between the inner boards of a pile of the inner board. A radio heater is enclosed by a pressing member and connected to a radio heater device, the pressing member presses the pile of the inner boards and the conduction pieces is heated to melt the prepregs which release resin to connect the overlapped inner boards within a short period of time.

Abstract: A clamp device which includes a base has a recess defined between two protrusions, and a chamber is defined in an inside of one of the two protrusions. A friction pad is attached to an inside of the other of the two protrusions. A frame with an inclined plate is received in the chamber and two parallel rails extend from a top surface of the inclined plate. A roller is received in the chamber and two grooves are defined in an outer surface of the roller. A friction member is mounted to the roller and located between the two grooves so that the rails are movably engaged with the grooves. A shank of a tool can be held by the friction member and the friction pad.

Abstract: A foldable paperboard table includes two first paperboards each having two first slits on lower edge thereof and two second paperboards each having two second slits on a top edge thereof. The four paperboards are interconnected with each other by engaging the first slits with the second slits to become a base portion. A top having flaps is connected to a top of the base portion and each flap has a side slit so that the flaps are folded to let each side of the first paperboards and the second paperboards engage with the side slits of the flaps to secure the top.