Timing belts

The synchronous toothed belts are flat belts that are fitted with transverse teeth around their inner and possibly outer circumference. The fibre that forms the skeleton of the belt is wound into a helical shape on a mould and then vulcanised (rubber) or encapsulated (polyurethane) with a compound to form the body of the belt including the toothing.

Conventional toothed belts are manufactured as a sleeve from which the specific belt width required is cut. Construction details such as overall thickness or filament fit height may vary slightly between manufacturers. However, the exact tooth shape must always be maintained to fit the same profile pulley.

Fibre

• Steel: Used in combination with a polyurethane body.
• Glass: Used in combination with a neoprene body.
• Kevlar (Aramid): Aromatic polyamide Kevlar is the best known aramid (para-amide nylon) fiber. The fibre has very high strength and is used in the manufacture of high load belts or belts designed for wet environments. Both neoprene and polyurethane belts can be fitted with aramid fibre.

Belt body

• Neoprene (CR, polychloroprene): used in combination with glass fibre for the production of belts. The belts are resistant to oil, water, ozone, ageing and have excellent mechanical properties.
• Polyurethane: It is used in combination with steel fibre for the production of belts. The belts are resistant to oil, gasoline, water, ozone and have excellent mechanical resistance.
• Special compounds: They are used for the manufacture of high load belts.
   

Gear profiles

Odd-numbered

The trapezoidal (trapezoidal) tooth profile was the first profile to be used in the manufacture of CTB (XL, L, H....) inch toothed belts. The gearing has excellent mechanical tensile strength. Nowadays, metric toothed belts (T,AT), which are mainly used as drive belts, are also fitted with this profile. For greater durability and reduced friction, the underside of the teeth of neoprene belts is covered with nylon fabric.

Half round

A modern tooth shape that is fitted to HTD, STD profile belts and all high performance belts (Falcon, Polychain, Blackhawk). The semicircular tooth has a quieter running action compared to the trapezoidal tooth and, above all, more precise timing. The classic half-round tooth has seen a few more modifications over time by some manufacturers, such as a groove on the top of the tooth or a parabolic shape with a shrunken top (STD). However, all of these improvements are based on the original half-round shape and only improve the ramp-up and timing characteristics of the belts. For greater durability and reduced friction, the underside of the teeth on neoprene belts are covered with nylon fabric.

Parabolic

It is used for the STD (supertorquedrive) profile. This profile provides precise timing and also a high power transfer, similar to the HTD profile.

Self-guiding (selftrack)

Specially adapted gearing that keeps the belt in a central position on the pulleys without the need for sidewalls. There are several variations of these types of gearing:

• TK, ATK: The classic T or AT profile, which has a 6mm (K6) or 13mm (K13) wide guide wedge in the centre of the gearing.
• BAT: The classic AT profile, which has an arc-shaped toothing (B).
• BATK: A classic AT profile, the toothing of which is shaped into an arc (B) and a guide wedge (K) is placed in the centre.
• SFAT: A classic AT profile that is offset halfway along its width by half a tooth.
• EAGLE: The two rows of teeth rise in a vertical, semi-vertical alignment.

Identification of the belt

If you don't know the designation of the toothed belt that your drive is equipped with, it's fairly easy to identify it using the rules below. The belt designation usually includes a profile - length - width designation.

1. Tooth pitch
   • This is the first and most important figure to find out. Tooth pitch is the length between the centres of the tops of two adjacent teeth. The most accurate way to determine the pitch is to divide the total length of the belt by the number of teeth.
2. Tooth profile (tooth shape)
   • Determine the type of belt by the tooth shape and the material of which the belt is made and find the profile with the correct pitch. The result should be the profile you are looking for, for example HTD5M, XL, T5, AT5, etc.
3. Length and width
   • Search for your desired length in the dimension range of the profile. The standard widths are also listed there, including the correct designation.

A simple way to identify the belt can be to search for the belt using the parameter table in our Online e-shop. For non-standard designs, consult our sales staff.
 

Types of toothed belts supplied

Common toothed belts

• Standard belts: common and high performance belts from the dimensional ranges listed in the catalogue. We keep in stock complete dimensional ranges of all profiles used. We keep most lengths as a sleeve from which the required belt and width is cut at the time of order.

Self-guiding belts

• As self-guiding (selftrack) belts always have a mirror-image left and right side in relation to the longitudinal axis, they are not produced as a sleeve but as separate belts. We usually do not keep these belts in stock and can provide them on order.

Toothed belts

• Metrails are manufactured in identical tooth profiles as conventional endless belts. Standard roll length is 30 or 50 metres. We will cut the required length of a given width of yardage by you at the time of order.

Production and modification of toothed belts

• Production from "V" webs: the endless belt is made by joining (welding) PU webs. The belt has 50% strength at the point of connection. This type of belts is suitable for transport purposes and lighter drives.
• Customized production "FLEX". The endless PU belt is manufactured in the classic way without the existence of a joint. The tensile carcass is unbroken throughout its length and is encased in a polyurethane compound in the mould.

Mechanical modification of toothed belts

• Polyurethane toothed belts can be mechanically modified, for example by cutting holes, milling off part of the toothing or grinding. These modifications can be combined with the fitting of a carrier or the application of a surface coating on the back of the belt.

Timing belts with toothed belt drives

• Thanks to thermal welding, it is possible to weld drifters of various shapes and sizes onto the back of polyurethane belts. The location, number, spacing and shape of the drift bearers are realized according to the customer's requirements according to the supplied technical drawing.

Surface layers

• Transport surface layers can be applied (gluing, spraying) to the belts. The most commonly used surfaces are supergrip, linatex, celoflex or polyurethane.