Our society Handling chains Other RAFER products Aprons, cogwheels ... Expertise, tests and follow-ups Contact us / Your request Home > Glossary Rafer: Glossary Custom handling chains Adjustment: Assembly of an outer containing part (bore) and a contained inner part (shaft). Male (shaft) and female (bore) parts have the same nominal size but different tolerances providing either positive play, tightening, or uncertain play. Boring: Operation which consists in carefully machining the interior surface of a cylinder or any other hollow part. It is also the result of this operation. Shaft: Mechanical organ transmitting power in the form of torque and rotational movement. The cylindrical shape of this organ is the origin of its name. Axis: Rectilinear mechanical part around which one or more other parts rotates, it is only used to guide in rotation or translation. The choice of the diameter of an axis is very important. For good guidance, the length must be at least twice as large as the diameter. The axes of these chains are generally solid, but they can be hollow intended for the attachment of accessories or spacers connecting two chains working in parallel. Burr: Refers to an involuntary surplus of material often very thin, as if the material had burrowed. It is unsightly and can be sharp. Bloom: steel bar with a square or rectangular section greater than a 120 mm square (160 mm in certain steelmakers), of variable length intended to be used in rolling mill trains called finishing trains Bolt: Assembly component made up of a screw with uniform thread and flat end (or threaded rod), and a nut (and possibly a washer). Cementation: Thermochemical treatment which consists in making carbon superficially penetrate into a steel, the percentage of carbon of which is insufficient to take quenching in order to transform it on the surface into a highly carburized steel capable of being quenched. Breaking load: Weight of the load that causes the chain to break (permanent deformation or destruction) Key: Metal anchor forcibly inserted into a notch made in one part to press it against another or between two parts for them. make united and prevent rotation. Safety factor: To determine the breaking load of a chain, it is necessary to apply a safety factor of the force F. Breaking load = F x safety factor This coefficient depends on the operating conditions. It can vary between 5 and 12, but is generally between 7 and 10. However, it is advisable to check the articulation pressure, before the final choice of the chain, because this one can be a determining element. Coefficient of pulling (CT): Variable parameter according to the condition of the raceway, lubrication, the diameter of the chain roller is: -0.10 for a chain with standard rollers, well lubricated and clean raceway -0.15 for a chain with standard rollers, uncertain lubrication and cluttered track -0.20 for a chain with small rollers with uncertain lubrication and cluttered track -0.33 for direct friction of the plates on steel track -0.02 to 0.05 for ball rollers (the larger the diameter of the roller, the lower the coefficient) Conveyor: Continuous handling device in a closed circuit, used for the air or ground transport of loads or materials. Screen: handling device used to remove the rubbish that accumulates on the grids. Teeth: All the teeth of a toothed wheel, is generally cut, it can also be flame-cut and ground for special profiles or for very large rollers. Pitch diameter: distance between the center of the wheel and the approximate middle of the teeth. DP = pitch / sin (180 ° / no. Of teeth) Ductility: Refers to the capacity of a material to deform plastically without breaking. Failure occurs when a defect (crack or cavity) becomes critical and propagates. Bushing: Cylindrical metal tip used to assemble two parts, while protecting the axis. Hardness: For metals, defines the resistance a surface of the sample opposes to the penetration of a harder object, for example the ball or the point of Lock: Structure inserted between two bodies of water with different level regimes, which allows buildings to pass from one to the other thanks to the operation of mobile elements, doors and valves. Elevator: Device or machine used to transport vertically, or on steep slopes, loads or materials. Enamelling: deposit on a metal, or another support, a vitreous, transparent or colored layer. The part to be enameled is covered with pigments, suspended in a volatile oil, and is then subjected to a temperature of around 800 ° C: the oil evaporates and the molten pigments are bound to the support. Enamelled parts have high durability, high resistance to scratches and chemicals, and are easy to clean. Spacer: tube-shaped part intended to keep the gap between 2 ball bearings constant. Asphalt: A metered mixture of aggregates and filler coated with bitumen or tar, used for the upper layers of pavements and for waterproof coatings of canals or dams. Shoulder: Sudden change in diameter, the purpose of which is generally to serve as a bearing surface for another part. Oven: Room where the temperature is very high and the heat humid. Excavator: Earthmoving machine equipped with a bucket chain mounted on an elinde or a bucket wheel. Thread: Consists of one or more helical grooves on a cylindrical outer surface. Roller: Roller having a diameter greater than the height of the plates. They allow the chain to roll on a flat surface. The rollers can be straight or shouldered to provide lateral guidance. The straight or shouldered rollers are made of treated steel Bucket: A sort of trough of variable capacity and shape, used in a number of handling devices (dredger, elevator, excavator, etc.) to dig the ground. Pin: Small piece of metal that passes through the end of certain elements so that the whole constitutes a rigid removable assembly. It makes it possible to immobilize or position a part in relation to another, to serve as an axis and to serve as a safety part (shear in case of overload) Lubricator: Device which, in a machine, automatically supplies the moving parts with grease or lubricant. Shot blasting machine: machine which projects shot in the form of micro-balls to strip a surface of the material which covers it. Seizure: Mechanical accident between two metal surfaces rubbing against each other, when metal particles detach from one of them and scratch the other more or less deeply, causing heating, then welding of the surfaces present. Log: Trunk of the felled tree, topped and free of the crown and branches. Guiding / Alignment: The quality of the guiding of the chain during its movement as well as the alignment of the sprockets which drive it is essential. These elements should be checked systematically before starting any new equipment. Clearance: Space left between two imperfectly assembled pieces. As it is impossible to make parts with perfect geometry, play is a necessity in the assembly of the elements of a mechanism. Joint: Device allowing the transmission of a rotational movement between two shafts whose relative position is poorly defined, incorrect, or variable. Rolling mill: industrial installation aimed at reducing the thickness of a material (generally metal). It also allows the production of profiled bars (long products). Yield strength: Stress at which a material begins to deform irreversibly. Lubrication: It is recommended to lubricate the slack return end of the chain. This facilitates access to the lubricant in the heart of the chain joint. The quality of the lubricant used as well as the care taken in its application to the chain can significantly modify its behavior and its service life. Mesh: Metal plates connecting the articulation pieces. There are the inner meshes in direct contact with the bushings, and the outer meshes in direct contact with the axle. Two inner stitches, as well as two outer stitches form a link. Self-locking nut junction links: the two pins are riveted to a plate at one end, the other end receiving a junction plate immobilized by self-locking nuts. Pinned pin junction links: where the junction plate is immobilized by pins to facilitate their removal. For some applications we can deliver chains with outer links pinned to one side. Flat: Flat surface on a cylindrical part. Hub: Central part on which are assembled the parts which must turn around an axis. It can be offset or symmetrical (wheel without hub = disc). Nitriding: Thermochemical treatment leading to the formation of nitride (s), aimed at the surface hardening of the treated parts. Pitch: Refers to the distance between 2 primitive centers of consecutive axes. The pitch is to be chosen according to the conditions of use, the type of product to be transported, the frequency of accessories, the space available, etc. Not all the step values, also established according to a normal series, are possible: see the table in chapter 2 giving the preferred steps. Steps at intermediate values or steps in inches can be made. Downtime / Storage Periods: Some applications may have extended downtime periods. It is absolutely necessary to take all possible precautions to protect the chain from corrosion by applying a suitable lubricant. Plates with fasteners: produced either by bending or in the form of brackets attached by welding or riveting: o M fasteners with one or more holes which form an attachment plane parallel to the plates. o K fasteners with one or more holes which form a fixing plane perpendicular to the plates with choice of three hole center distance values (K2 with short, medium and long center distance), the width of the fasteners varying accordingly. These fasteners can be made on the inner and outer links, on one side or both, according to a frequency and an arrangement to be specified when ordering. o Special fasteners can be made on request for sufficient quantities Polishing: Make smooth and possibly shiny Offset plates: asymmetric allowing loads to be placed directly on the chain running on straight rollers. These chains are generally used in parallel to form a mat and distribute the loads. Perforated plates: with one, two or three holes to receive fasteners or spacer bars. If these pass through the chain, it is necessary to make clearances on the teeth of the wheels. Weight of the deck: Total weight of the section considered, i.e. the entire moving part: chain + rollers + pallets + accessories + etc. Articulation pressure: In certain applications, the contact pressure in the articulations becomes a determining parameter, it is in fact this pressure which, with each oscillation of the chain when passing over the wheel, will cause wear of the chain. chain. This pressure must be monitored in particular in applications in an abrasive environment, without maintenance, in stainless steel chains, etc. P = F / S P in N / cm² F = tangential force in the chain in N S = projected diameter surface or Ø of l 'axis (in cm) x sleeve length (in cm) The values of P for standard chains can be: 4000 N / cm² with abundant oiling 3000 N / cm² with good maintenance and clean environment 1500 N / cm² with uncertain maintenance and dusty environment 1000 N / cm² without maintenance Groove: Long notch, of rectangular section, T-shaped, or dovetail, made in a room. Efficiency: Coefficient taking into account the efficiency of the components located between the motor and the control shaft: coupler, reduction gear, chain transmission, etc. Of course, these coefficients are cumulative. Furthermore, a coefficient of 1.05 is applied to each 180 ° winding. This corresponds to the losses due to the articulation movements of the chains, their positioning on the wheels and the rotation of the wheels + shafts assembly. Minimum tensile strength: Ranges, according to a series based on normal numbers, from 20 to 900 kN Rivet: Permanent assembly element. It is in the form of a cylindrical rod, generally metallic, solid or hollow which is provided at one of its ends with a head, that is to say a part of larger section. The other end will be flattened and widened by crushing, to secure the elements that we want to rivet together. Washer: Small drilled disc that is placed between a screw or a nut and the part to be tightened, to transmit and distribute the clamping force on the part. Toothed wheel: Organ of circular shape allowing to transmit the movement thanks to the teeth of which its periphery is furnished. The wheel makes it possible to transform the rotational movement into translation. The wheels used with the conveyor chains are made of mechanically welded steel or cast iron. The teeth are normally foundry or flame-cut but, on request, they can be supplied with cut teeth, which is essential when using bush chains. The hubs are offset with respect to the toothing plane, unless there is a specific specification specifying a symmetrical hub. The wheels can be supplied bored and grooved. In the case of a sloped key on an offset hub, the entry of the key is provided on the toothing side unless otherwise specified. Roller: Small cylindrical part of revolution in very hard steel, case-hardened, tempered or other treatment and perfectly polished, used in mechanical construction, in bearings. The rollers protect the bushings and prevent tooth wear. Ball bearing: A bearing has the utility of reducing the friction between 2 rotating parts, thus the bearing decreases the heat caused by the rotation. A bearing can also be used to reduce misalignment between two parts. You should know that there are several types of bearings: Ball bearing, roller bearing, needle bearing. Silo: tank intended to store bulk material Tension: Called “slack end adjustment” because a chain should not be tensioned. This adjustment will firstly allow the articulation clearances to be absorbed, and secondly to take up the elongation due to wear. Too much tension generates a strong increase in the articulation pressure and leads to premature wear of the chain. Tolerance: Inevitable imprecision of the production processes means that a part cannot be produced in strict accordance with the dimensions fixed in advance on the plan. We are therefore obliged to say that the dimension actually achieved is between two limit dimensions, compatible with correct operation of the part. The difference between these two dimensions constitutes tolerance. Wire train: rolling mill train, continuous, specializing in the production of wire rod (semi-finished product intended for processing). The installation is 300 to 400 m long. Heat treatment: of a piece of metal consists in subjecting it to structural transformations thanks to predetermined heating and cooling cycles in order to improve its mechanical characteristics: hardness, ductility, elastic limit, etc. Hopper: large funnel intended to store and then pour a heavy material (grain, sand, etc.) by gravity Tribofinishing: Incorporates polishing and deburring techniques; the ingredients are the abrasive media (ceramic, porcelain, plastic, metals), chemical additives and of course the equipment that generates the movements (vibrators, centrifuges, etc.). Rafer uses pebbles in pyramidal shapes to clean his mechanical parts. Fixing screw: Commonly called screw, is a mechanical member, comprising a threaded rod and a head; it is intended for fixing one or more parts by pressure. Galle Channel: Galle chains are made up of straight or hollowed-out links (or plates) and shouldered axles. The shoulders of the pins maintain the distance between the plates and allow the engagement with the pinion. The chains are said to be single, double or triple links depending on the desired tensile strength. Galle chains can transmit forces varying from a few hundred Newtons to more than a thousand kilo Newtons, while the speed must not exceed 20 m / min. Galle chains are used for low speed transmissions (draw bench) or to provide back and forth movements (freight elevator, dam valves, etc.). They therefore make it possible to transmit significant forces in a small footprint. Their design simplicity makes them suitable for applications in difficult environments (outdoors, temperature, etc.) Block chain: Block chains have high tensile strength in a small footprint. They are used for handling heavy or abrasive bodies or when severe impacts are expected (draw bench for example). In order to increase the life of the chain (better resistance to wear), the blocks are sometimes ringed. Roller chain : Single chain: Double chain: Triple chain: Multiple chain: Solid pin chain : Hollow pin chain : Crank link chain: Forged chain links: socket Chain: Roller smooth: roller supported: Quick connectors: Quick connectors pinned: Clip nuts: Hourglass command: Hourglass voltage or reference: mechanical Apron: Arrow: RAFER S.A.S. – 69, Route du Coin Z.I. de Fonsala BP92 – 42402 Saint-Chamond Cedex - FRANCE Tél. : +33 (0)4 77 31 73 73 - Fax. : +33 (0)4 77 22 11 57 - Mail : contact@rafer.fr Certificat n° 100118-C346 | ISO 9001 : 2008 - Voir notre certificat Iso Mentions légales - Garanties & CGV - Glossaire - FAQ - Plan du site - Crédit : Studio Marquise Accueil - Qui sommes-nous - Accueil type chaînes - Chaîne domaines - Tablier - Roues dentées - Expertise & tests - Assistance au montage - PSC - Formulaire de contact