Abstract: An apparatus for producing a double-walled tube of plastic material having an outer corrugated wall and an inner wall connected to the inner crests of the corrugated outer wall, in which an extrusion head is arranged coaxially within mold means formed by a plurality of mold sections traveling along endless paths and abutting along portions of the paths against each other to form a tubular mold having an inner corrugated surface. The injection head comprises two coaxially arranged annular extrusion nozzles having outlet ends axially spaced from each other through which plastic material is extruded.

Abstract: Apparatus for forming diagonally corrugated paperboard having a longitudinally elongated frame upon which is laterally mounted at least one corrugating unit. Each corrugating unit consists of a conveyor mechanism having a continuous loop belt with parallel grooves formed in its outer surface and a mechanism to force the web of paper being passed through the corrugating unit down into the grooves of the continuous loop belt. The parallel grooves in the outer surface of the continuous loop belt are oriented diagonally with respect to the direction of travel of the conveyor mechanism. The mechanism to force the web of paper down into the grooves of the belt comprises a plurality of rods that extend in a corresponding diagonal direction across the width of the belt and whose opposite ends are not secured to any structure but which are floatingly carried around a closed loop path structure.

Abstract: A high speed corrugator for producing corrugated thermoplastic tubing comprises a pair of complementary upper and lower mold assemblies each comprising an endless chain of articulately interconnected mold blocks and means for guiding the mold blocks along an endless track having a forward run and a return run, each mold block being complimentary to a respective mold block of the other assembly, the mold blocks co-operating in pairs along said forward run to form an axially extending tunnel defining a tubular mold having a corrugated wall. The mold assemblies are positioned so as to locate the extrusion head at the entrance to the tunnel coaxially therewith, and extruded thermoplastic material is expanded by blow molding to conform to the interior surface of the mold. Cooling air is fed along an air distributor duct extending along the tunnel for cooling the molded thermoplastic, the cooling air being divided from the blow molding air by a baffle.

Abstract: A method of and apparatus for making toothed belts of rubber or rubber-like elastic synthetic materials with an enveloping fabric covering, the belt teeth, according to which an enveloping fabric strip is folded into successive folds corresponding to the belt teeth to be formed, and the cavities defining folded portions on the inside of said fabric strip are filled with elastomeric material of the type of which the belt teeth are to be made, whereupon layers of elastomeric material and straight members making up the remainder of the belt to be made are placed upon each other to build up the belt, whereafter the thus obtained assembly is vulcanized.

Abstract: The angular position of a wrap control roll about a paper web preheating roll is remotely adjusted to any one of a plurality of predetermined set positions by an index control over the adjustment power train. The index conrol comprises a remote positioned, console mounted rotary switch having contact positions corresponding to the predetermined wrap control roll set positions. Cooperative switches mounted in an adjustment drive follower mechanism continue the circuit continuity to a solenoid activated drive motor reversing switch. A breaker unit within the follower mechanism is directly driven by the adjustment power train to open the motor switch when the breaker unit is correctly aligned with the desired set position.

Abstract: In a sheet corrugating machine used to fabricate corrugated paper board from rolls of sheet stock, the formed sheet is held tightly to the undulating surface of one corrugating roll between the corrugating nip and a liner sheet application nip by a vacuum system within the corrugating roll. The corrugating roll vacuum system comprises apertures through the roll shell within the corrugation valleys. Such apertures communicate with longitudinal conduits disposed about the internal periphery of the roll shell and extended through one axial end of the roll. A stationary, sliding seal vacuum box evacuates only those conduits rotatively passing through the desired arc thereby leaving the roll journals free to simultaneously conduct roll heating steam therethrough.