Overview

This technical document comprehensively details specifications, materials, load capacities, and application guidelines for tensioners, idle sprockets, pulleys, idler pins, spring tighteners, tensioner brackets, adjustable tighteners, plate tighteners, vertical/horizontal tighteners, and chain bolts used in chain and belt drive systems. It emphasizes component design variations, bearing types, material properties, and safety recommendations for mechanical power transmission and lifting applications.

1. Tensioners, Idle Sprockets, and Pulleys

• Plastic Idle Sprockets (BIS Series): Made from glass-fiber reinforced polyamide plastic with moulded-in ball bearings locked by retaining rings. Specifications include teeth count, pitch and outer diameters, thickness, and idler pin dimensions. Bearings support radial loads up to speeds of 3500 min⁻¹.
• Steel Idle Sprockets (SIS Series): Constructed from S45C steel with induction hardened teeth tops and black oxide finish. Pressed-in ball bearings, including sealed types for dusty environments, are used. Load ratings and dimensions are specified; some models lack induction hardening.
• Stainless Steel Idle Sprockets (SIS-S Series): Made from SUS304 stainless steel with pressed-in stainless steel bearings, offering corrosion resistance with similar load and dimension specifications as steel sprockets.
• Flanged Idle Sprockets and Pulleys (FIP, FIPS, RABS Series): Available in plastic and steel with electroless nickel plating. Bearings are moulded-in or retaining ring locked. Designed for flat or timing belt applications with flange heights accommodating belt thickness. Used as driven rollers or tensioners.
• Crown Pulleys (CTR, CTRS Series): Plastic and steel variants with moulded-in or retaining ring locked bearings. Detailed dimensions, bearing types, load capacities, and speed ratings are provided.
• Idle Pulleys (NIP, NIPS Series): Plastic, steel, and stainless steel options with various ball bearings. Designed for chain drive applications as driven rollers, with full technical data on dimensions, load ratings, and speed limits.

2. General Technical Information and Recommendations

• Bearings are secured by retaining rings to ensure assembly integrity.
• Allowable bearing radial loads correspond to an average service life of 3,000 hours, varying by bearing type and operating speed.
• Steel sprocket teeth are induction hardened for durability except where noted.
• Plastic components utilize glass-fiber reinforced polyamide for strength.
• Electroless nickel plating on steel parts enhances corrosion resistance.
• Proper idler pin dimensions and weights are specified for correct assembly and performance.
• Recommended applications include chain tensioners, conveyor rollers, and belt drive idlers.

3. Idler Pulleys, Pins, and Spring Tighteners

• Idler Pulleys and Bearings: Steel (S45C) with electroless nickel plating and plastic V idle pulleys made from reinforced polyamide. Bearings include various ball bearing types locked by retaining rings. Speed ratings up to 3500 min⁻¹ with detailed dimensions and weights provided.
• Idler Pins: Available in steel (S45C), stainless steel (SUS303), with black oxide finish options. Features include flanged and adjustable designs with grease nipples and retaining collars adjustable via setscrews. Comprehensive size and weight charts included.
• Spring Tighteners: Automatically adjust chain or belt slack, providing high tension and easy tensioning. Materials include steel (SPCC, SS400, S45C), stainless steel (SUS304), and UHMWPE. Technical data covers spring constants, tensions, diameters, and lengths. Installation can be horizontal or vertical with hex socket screws for adjustment. Long-term use may reduce tension capacity; smooth operation depends on proper idler pin and guide shaft condition.

4. Tensioner Brackets and Adjustable Tighteners

• Tensioner Brackets: Made from steel (SPHC, SPCC) with black or cation-coated finishes. Various sizes (AST65, AST100) with detailed dimensions and weights. Used with spring tighteners and idler pins.
• Adjustable Tighteners (SAT Series): Designed for long tension-adjusting strokes and high tension applications. Materials include steel (SPCC, SCM435, S45C, SS400) with black oxide or chrome plating. Installation involves idler pin and pulley placement, belt positioning, tension adjustment via screw, and securing with a nut. Caution advised to avoid tensioning in the opposite direction to prevent damage.

5. Plate Tighteners and Vertical/Horizontal Tighteners

• Plate Tighteners (SRT, CRT): Crank and straight plate types made from steel (SPHC) with black cation coating. Dimensions and weights provided with mounting hole and thread specifications.
• Vertical and Horizontal Tighteners (FLT, BAT, ANT Series): Operate by applying clockwise force to generate tension; initial tension is zero. Materials include cast iron (FCD450, FC250) and steel (S45C, S50C) with powder baking or black coatings. Design notes emphasize avoiding counterclockwise force to prevent spring damage. Detailed size charts include arm length, swing angle, teeth count, and weights.

6. Chain Bolts and Nuts

• Chain Bolts: Stainless steel bolts available in right-hand thread only. Types include single-end (CBS1, CBS2) and double-end (CBD1) bolts in steel and stainless steel. Sizes range from 25 to 100 mm with varying load capacities.
• Chain Nuts (CNS1): Steel nuts with black oxide finish, heat treated to Rc33-39, compatible with chain bolts for tension adjustment.
• Materials and Finishes: SCM435 steel for most bolts; SUS304 stainless steel for corrosion resistance. Black oxide finish on steel components. Heat treatment ensures durability.
• Load Capacities: Specified in Newtons, ranging from 950 N to 26,400 N depending on size and material. Load ratings apply to tensile loads only.
• Safety Recommendations: No personnel should be under lifting devices using chain bolts. Safety devices are recommended to prevent accidents from chain or bolt failure. Regular inspection and replacement are mandatory.

7. Accessories and Additional Components

• Locating receivers, protective covers, adjustable-torque wrenches, and various clamping locators support installation and maintenance.
• CAD downloads are available for design integration at https://www.imao.com/en/.

8. Critical Notes and Best Practices

• Proper bearing and idler pin selection is essential for smooth operation and longevity.
• Spring tighteners require correct installation and periodic maintenance to maintain tension performance.
• Applying tension forces in the correct direction is crucial to avoid damage to tighteners and springs.
• Strict safety precautions must be observed when using chain bolts in lifting applications to prevent accidents.

Summary Tables and Data Highlights

• Detailed tables provide dimensional data (diameters, thicknesses, lengths), bearing types, allowable radial loads at various speeds, and component weights.
• Load ratings vary from several hundred to several thousand Newtons depending on bearing and component size.
• Speed ratings typically reach up to 3500 min⁻¹, with specific limits per bearing type.

Manufacturer Contact

IMAO Corporation, 2002 Senbiki, Seki, Gifu 501-3954, Japan
Tel: +81 575 28 5823
Website: www.imao.com/en