English Pitch Timing Belts

English pitch timing belts mate with same-pitch timing pulleys in power transmission systems where maintenance of speed ratio is an important design consideration. English pitch is the distance between belt teeth based on inches (in). With English pitch timing belts, a timing pulley transmits force to the belt via evenly-spaced grooves that mate with the teeth in the belt. These same grooves and teeth prevent belt slippage. Synchronous belt drives are highly-efficient devices. Synchronous belts come in a wide variety of materials and reinforcements. English pitch timing belts or imperial pitch timing belts have a trapezoidal tooth form.

ANSI pitch is the most important specification to consider when searching for English pitch timing belts. Pitch is the distance from one tooth center to the adjacent tooth center. English or imperial pitch is also referred to as H-pitch. Choices include 0.080" (MXL), 0.0816" (40 DP), 0.200" (XL), 0.375" (L), 0.500" (H), 0.875" (XH), and .250" (XXH). The geometry of English pitch timing belts is also important to consider. Belt width, number of teeth, and length are the most important geometric parameters. For a given pitch, a selected number of teeth will determine the belt length. Likewise, a specified belt length will determine the number of teeth in English pitch timing belts.

Materials of construction for English pitch timing belts include neoprene, polyurethane, rubber, and urethane. Selection factors may include operating tension, environmental factors such as humidity and temperature, and power transmission. Consult the belt manufacturer for details. Many English pitch timing belts are reinforced with fibers or cables in the belt’s tension area. Reinforcement can significantly enhance the belt’s maximum operating tension. Metallic and non-metallic reinforcement fibers are also available. Common materials include fiberglass, Kevlar^® (DuPont), polyester, and steel. 

Product specifications to consider when specifying English pitch timing belts include ultimate tensile strength, maximum operating speed, and operating temperature. The ultimate tensile strength (UTS) is the breaking strength or tension rating. Many belts are rated for a maximum operating speed; this is dependent on both the material and belt geometry.  Some English pitch timing belts are double-sided, truly endless, or open-ended.  Double-sided belts have teeth on both sides of belt.  Truly endless belts are manufactured as one closed loop; not spliced. Open-ended English pitch timing belts come in a roll and may be cut and spliced to desired length and number of teeth.

Pages: 1 - 3 of 68