Patents by Inventor Johannes Lefferts
Johannes Lefferts has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5514456Abstract: A spiral link belt has a plurality of plastic helices connected to one another which interlock in the manner of a slide fastener with neighboring helices. Overlapping widening arcs form a channel and pintle wires run through the channels and thereby connect the helices. Flat wires are inserted in the helices to reduce the air permeability of the spiral link belt. The flat wires are tilted relative to the plane of the spiral link belt. The flat wire running inside a helix can be wider than the smallest distance between the two helices connected to this helix. During production, the spiral link belt is thermoset only after the insertion of the flat wires.Type: GrantFiled: February 3, 1995Date of Patent: May 7, 1996Assignee: SITEG Siebtechnik GmbHInventor: Johannes Lefferts
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Patent number: 5183442Abstract: A double helix is formed from two partial helices each having the same winding direction and each having an oval cross-section with nearly straight upper and lower winding legs. The facing winding arcs of the two partial helices encircle each other. The upper winding legs of the partial helices extend at a different angle with respect to the longitudinal axis of the partial helices than the lower winding legs of the respective partial helix. The upper winding legs of one partial helix extend at the same angle with respect to the longitudinal axis as the lower winding legs of the other partial helix and vice versa.Type: GrantFiled: December 9, 1991Date of Patent: February 2, 1993Assignee: Siteg Siebtechnik GmbHInventor: Johannes Lefferts
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Patent number: 4796749Abstract: A spiral link belt comprising a multiplicity of synthetic resin helices consisting of flat winding lets and winding arcs with the winding arcs of a helix meshing in zipper fashion with the winding arcs of the adjacent helix. Pintle wires are inserted into the channels formed by the meshing winding arcs of each two helices. A plurality of helices consist of at least two components, the first component being disposed on the inside of the helix and the second component being disposed on the outside of the helix. Preferably, the second component which is disposed on the outside of the helix, is embedded in a groove in the first component.Type: GrantFiled: November 6, 1987Date of Patent: January 10, 1989Assignee: Siteg Siebtechnik GmbHInventor: Johannes Lefferts
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Patent number: 4696852Abstract: The spiral link belt consists of a multiplicity of synthetic resin helices in which the windings of one helix mesh with the windings of the adjacent helices in zipper fashion. Pintle wires are inserted into the channels formed by the meshing windings of each of two helices with the winding of the helices penetrating into the material of the pintle wires. The helices are of oval shape with heads at the winding arcs widened in the longitudinal direction of the helices. The width of the heads at the winding arcs is about one and one half to two times the diameter of the wire form which the helices are wound. The helix wire can also have a kidney-, U-or V- shaped cross section with a concave and a a convex side and can be wound so that the concave side faces inwardly or outwardly. The helices are flattened in the region of the winding arcs. Flattening is effected during thermosetting.Type: GrantFiled: March 27, 1986Date of Patent: September 29, 1987Assignee: Siteg Siebtechnik GmbHInventor: Johannes Lefferts
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Patent number: 4650709Abstract: A helix of great length wherein the structure is filled with a filler and wherein the structure is produced by a practice in which the helix structure and filler material are caused to rotate about each other upstream of the point of convergence, while the helix retains its orientation, and the speed of advance of the helix and the speed at which the filler material and helix are rotated are so adjusted that the helix is advanced by one winding during each rotation. The filler material is a braided tubing. A core preferably prevents the tubing from collapsing.Type: GrantFiled: October 23, 1985Date of Patent: March 17, 1987Assignee: Siteg Siebtechnik GmbHInventor: Johannes Lefferts
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Patent number: 4575472Abstract: Double helices each comprising two helix elements made from plastic wire with the longitudinal axes of the two helix elements extending in parallel and with the windings of the two helix elements intertwined, the double helices being formed by winding two plastic wires in parallel and without twist on a mandrel and being used to assemble a spiral belt by interengaging in zipper fashion a multiplicity of helices via meshing the windings of one helix with the windings of the next helix, and by inserting a pintle wire into the passage formed by the overlapping windings.Type: GrantFiled: February 7, 1984Date of Patent: March 11, 1986Assignee: SITEG Siebtechnik GmbHInventor: Johannes Lefferts
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Patent number: 4564992Abstract: A helix of great length wherein the structure is filled with a filler and wherein the structure is produced by a practice in which the helix structure and filler material are caused to rotate about each other upstream of the point of convergence, while the helix retains its orientation, and the speed of advance of the helix and the speed at which the filler material and helix are rotated are so adjusted that the helix is advanced by one winding during each rotation.Type: GrantFiled: July 13, 1983Date of Patent: January 21, 1986Assignee: Siteg Siebtechnik GmbHInventor: Johannes Lefferts
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Patent number: 4451957Abstract: A slide apparatus for joining ends of a belt of the type having a plurality of transverse interlocked spiral elements. The slide apparatus includes two tapered overlapping channels for the reception of the overlapping belt ends so that upon movement of the slide apparatus the overlap of the belt ends will be reduced. The tapered channels terminate in a common narrow channel having a width equal to the overlapped end spiral elements so that upon passage of the two belt ends from the narrow channel a spring biased pusher element will force the overlapped spiral elements into meshing engagement, wherein a pintle wire, inserted into the passage defined by the intermeshed spiral elements, connects the belt ends.Type: GrantFiled: May 21, 1981Date of Patent: June 5, 1984Assignee: Steg Siebtechnik GmbHInventors: Johannes Lefferts, Roelof Roelofs
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Patent number: 4392902Abstract: A sieve belt formed of a multiplicity of helices of thermosettable synthetic resin monofilament. Adjacent helices are meshed together so that overlapping windings form a channel through which a pintle-filament is passed. The helices are free of bias and torsion both before and after being assembled in the belt. After assembly the belt is stretched longitudinally and thermoset, causing the helix windings to penetrate slightly into the pintle-filament to tightly surround it with line contact, and to flatten the long legs of the oval windings between pintle-filaments.Type: GrantFiled: March 25, 1982Date of Patent: July 12, 1983Assignee: Steg Siebtechnik GmbHInventor: Johannes Lefferts
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Patent number: 4362776Abstract: The sieve belt is comprised of a multiplicity of helices made of thermosettable synthetic resin material which are interlocked with each other by inserting a plurality of pintle wires into the channels defined by the overlapping helices. For controlling the air permeability of the sieve belt, the hollow interiors of the helices are filled with a filler material comprised of crimped synthetic filaments.Type: GrantFiled: October 14, 1981Date of Patent: December 7, 1982Assignee: Siteg Siebtechnik GmbHInventors: Johannes Lefferts, Roelof Roelofs
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Patent number: 4346138Abstract: A sieve belt formed of a multiplicity of helices of thermosettable synthetic resin monofilament. Adjacent helices are meshed together so that overlapping windings form a channel through which a pintle-filament is passed. The helices are free of bias and torsion both before and after being assembled in the belt. After assembly the belt is stretched longitudinally and thermoset, causing the helix windings to penetrate slightly into the pintle-filament to tightly surround it with line contact, and to flatten the long legs of the oval windings between pintle-filaments.Type: GrantFiled: January 11, 1980Date of Patent: August 24, 1982Assignee: SITEG Siebtechnik GmbHInventor: Johannes Lefferts