Patent ID: 6968943
Filing Date: 2005-11-29
Classification: A21C,B65G,F16C

Abstract:
1. In a conveyor for commercial proofers and ovens of the type comprising: a conveyor track of the type having a bottom wall, opposed side walls, and a top wall having a slot formed therein; and a conveyor chain including a plurality of substantially identical carriages each comprising: (a) an elongate body extending between first and second ends; (b) at least one first wheel pair supported on the body for rotation about an axis located adjacent the first end of the body; (c) self-lubricated bearings supporting the first wheel pair for rotation relative to the body; (d) a second wheel pair supported on the body at a location between the first and second ends for rotation about an axis extending perpendicularly to the axis of rotation of the first wheel pair; (e) self-lubricated bearings supporting the second wheel pair for rotation relative to the body; and means connecting the first end of one of each carriage to the second end of the next adjacent carriage in the conveyor chain; wherein the self-lubricated bearings supporting the first and second wheel pairs comprise antifriction bearings including: races having a surface finish of ≦45.0 □in. rms and constructed from a temperature resistant material selected from the group consisting of silicon nitride ceramic, Stellite®, T1 high temperature tool steel, BG-42 high temperature corrosion resistant tool steel, M2 high temperature tool steel, M50 high temperature tool steel, high molybdenum 440C stainless steel, 440C stainless steel, Cronidur 30® nitrited corrosion resistant tool steel, and 52100 bearing steel; balls formed from a material selected from the group consisting of silicon nitride, alumina, zirconia, silicon carbide, 52100 bearing steel, 440C stainless steel, BG-42 high temperature corrosion resistant tool steel, M50 high temperature tool steel and characterized by: sphericity <20 □in., surface finish <1.6 □in. Ra, and diameter variation <40 □in.; radial internal clearance between about 39.37 □in. and about 0.0126 in.; races and balls coated with a solid lubricant having a thickness of between about 2,000 angstroms and about 0.003 in. and comprising a material selected from the group consisting of: tungsten disulfide, molybdenum disulfide, titanium nitride, silver, carbide diamond, and boron nitride; self-lubricating retainers formed from a material selected from the group consisting of: Vespel® (polyamide), molybdenum disulfide impregnated Teflon®, graphite, fiberglass reinforced phenolic; and stainless steel coated with tungsten disulfide solid lubricant; the internal volumes of the bearings being completely filled with a high temperature solid lubricant selected from the group consisting of molybdenum disulfide, graphite, and grease impregnated polytetrafluoroethylene (PTFE); and bearing seals selected from the group consisting of: labyrinth fiberglass reinforced PTFE seals; viton rubber seals with stainless steel backings; and stainless steel shields with a 0.001″ gap between the inner race.