Abstract: A machine and method for cutting notches with rounded inner corners in wood pallets. The completed notches are made in one pass through the machine as the pallet passes over three successive stages of cutting. The first stage makes six vertical cuts for each notch, the inner four cuts to the depth of the notch and the outer cuts decreased in depth by the radius of the rounded corner and the outer cut being laterally separated from the adjacent deeper cut by a distance also equal to the radius of the rounded corner. The second stage, with a horizontal cut removes the wood between the inner four cuts and the third stage cuts out the rounded corner with a horizontally positioned radius cutter.

Abstract: The nut is for repairing leaking bolt holes in flanged pipe joints by means of a closed-end nut having a sharp circular projection on its open end. When this sealing nut is substituted for existing nuts on bolts in the flanged joint and tightened, the nut, which is hardened, cuts a circular groove in the face of the flange that makes a metal-to-metal seal to close leaks at bolt holes. The bolts may be same diameter as the existing bolts and may be installed one at a time to accomplish the repair without reducing pressure in the pipe. Leakage from between the flanges at their perimeter is closed off by sealing in a conventional manner by welding a band around the perimeter of the flanges before the bolt hole sealing is started.

Abstract: The chair is suspended from a elevated aerial ladder and hangs by gravity in a stable manner. The stability enables a worker, such as a sign painter, to be seated while performing his task without being disturbed by tilting and swaying. The stability is due to suspending the chair from a point well above the worker's head which causes the chair to hang stably. The worker can change the direction in which the chair faces by releasing a latch and manually swivelling the chair to a desired direction where he then holds it by reengaging the latch. No power or hydraulic devices are required in achieving the vertical stability nor the swivelling and latching in desired directional position. Therefore the chair is useful on a simple aerial ladder or other type of aerial lift.

Abstract: An improvement in heat exchangers for hot air furnaces and water heaters. The improvement is a rotating damper having an opening above each flue that momentarily closes off the outlet of each flue in turn. This holding of hot gases provides more time for the transfer of heat before the gases are discharged to a chimney. The damper openings are sized and arranged so that at least one of the flues is open and one or more closed at any particular moment during the cycle. When a particular flue is opened by the rotating damper the held gases which have now cooled are discharged to the chimney and replaced by a new supply of hot gases. When this flue is closed by further rotation of the damper, it becomes a holding chamber for the hot gases. The other flues operate in turn in the same manner.