Renoldoffer a comprehensive range of transmission chain sprockets for British Standard chain up to two inch pitch, ensuring maximum working life and productivity for your application. Other sizes of sprocket, including those to American Standard dimensions, are available on request.

Special sprockets are also manufactured on request, in special materials or formats, normally to suit a specific applications in harsh or difficult drive situations, such as;

• Sprockets incorporating shafts


• Welded or detachable hubs


• Shear pin devices fitted


• Necklace sprockets made up of chain plates and individual tooth sections for turning large drums or tables.


• Combination sprockets (two or more sprockets combined having different pitch sizes and numbers of teeth).


• Sprockets in two or more sections, i.e. split sprockets or segmental sprockets.

Sprocket and Chain Compatibility

Most drives have an even number of pitches in the chain and by using a driver sprocket with an odd number of teeth, uniform wear distribution over both chain and sprocket teeth is ensured. Even numbers of teeth for both the driver and the driven sprockets can be used, but wear distribution on both the sprocket teeth and chain is poor.

Number of Teeth

The maximum number of teeth in any driven sprocket should not exceed 114. This limitation is due to the fact that for a given elongation of chain due to wear, the working pitch diameter of the chain on the sprocket increases in relation to the nominal pitch diameter, i.e. the chain assumes a higher position on the sprocket tooth. The allowable safe chain wear is considered to be in the order of 2% elongation over nominal length.

A simple formula for determining how much chain elongation a sprocket can accommodate is 200/N expressed as a percentage where N is the number of teeth on the largest sprocket in the drive system. It is good practice to have the sum of teeth not less than 50 where both the driver and the driven sprockets are operated by the same chain, e.g. on a 1:1 ratio drive. Both sprockets should have 25 teeth each.

Centre Distance

For optimum wear life, centre distance between two sprockets should normally be within the range 30 to 50 times the chain pitch. On drive proposals with centre distances below 30 pitches or greater than 2 metres, we would recommend that the drive details are discussed with our technical staff.

The minimum centre distance is sometimes governed by the amount of chain lap on the driver sprocket, our normal recommendation in this circumstance being not less than six teeth in engagement with the chain.

The centre distance is also governed by the desirability of using a chain with an uneven number of pitches to avoid the use of a cranked link, a practice that is not recommended except in special circumstances.

For a drive in the horizontal plane, the shortest centre distance possible should be used consonant with recommended chain lap (maximum six teeth) on the driver sprocket.

Renold DL Series Dual lead worm gears are constructed with two leads. One flank of the worm thread and its mating sides of the wheel teeth are manufactured with one lead, and the other flank and its mating wheel teeth to a slightly different lead.

As far as the worm is concerned this has the effect of producing a worm thread which increases in thickness from one end of the worm to the other.

If the worm is therefore moved in an axial direction when in mesh with the wormwheel, backlash between the pair can be adjusted to the required amount.

In practice, the gears are manufactured so that the initial backlash is achieved at a certain distance relative to the datum plane on the worm. The worm can then be adjusted from this point as and when necessary during the life of the gears.

The DL Series dual lead worm gear offers many advantages to the split worm gear design. It provides a kinematically correct gear, which can run in either direction of rotation, and on which the backlash is infinitely adjustable from an acceptable maximum to zero.

Precision dual lead backlash adjustable worm gears are widely used in rotary tables, cutter drives and machine tool positioning mechanisms.

Renold manufactures worm gears using the 'Holroyd' tooth form whichconforms to British standard 721. The leaving side contact pattern provides for a good oil entry which results inthe following benefits:

• 
  
  Increased lubrication
  
  


• 
  
  Increased efficiencies
  
  


• 
  
  Smoother running
  
  

Renold worm gears are widely respected for performance and reliability in a wide variety of drives ranging from large steel mill screw down mechanisms to high precision dual lead machine tool and rotary positioning systems.

Unrivalled Accuracy

Although Renold produces worm gears to BS 721, for greater control of manufacturing tolerances we use DIN 3962 and DIN 3974 for specifying grades of quality. Manufacturing quality is backed up by the latest inspection techniques and for high precision gears sets we can supply, in graph format, results of pitch, profile and transmission variations over 360 degrees of the worm gear set.

Approvals

Renold Gears is BS EN ISO 9001:2008 approved. All products are designed and manufactured within this Quality Assurance system.

Applications

Mining, Coal cutting machines, axle drives, civil engineering, cranes, trucks, dumpers, steel plants, screwdowns, wire and tube drawing, automotive, oil pump, fuel injection, power, coal pulverisers, steam turbines, machine tools, indexing heads, rotary tables

Renold Gears manufacture high quality, high specification loose helical and spur gears using leading edge gear technology. Our dedicated gear manufacturing machine shop, provides the facilities necessary to manufacture eithervolume or single components for bothprecision and commercial sectors.

Our experienced Engineering Department can advise on all areas of gear design - gear blank materials, heat treatments, surface treatments and full gear tooth geometry. Using kissoft gear design software our engineering teamare able to maximise gear performance and therefore provide a unique gear design and development service.

• High accuracy finish hobbed or ground gear teeth


• Helical/ Spur gears


• Volume or small batch production


• Custom tool profiles


• Gear grindingup to 350mm diameterand gearface widths up to 160mm


• Prototypes and master gears


• Kissoft gear designsoftware optimising gear performance

30 years of experience in producing superior chain technology has helped us to identify common challengesfacing our customers. To help address these challenges we have developed a new range of high performancesprockets, available from stock on same day despatch*.

The three main problem areas identified are:

'New Chain Fitted on to Old Sprockets'

Problem:

• Significantly reduces the newly installed chain's life

Solution:

• If the existing sprocket shows any signs of wear, replace it

Benefit:

• Increased service life of both chain and sprocket

'Low or Inconsistent Tooth Hardness'

Problem:

• Dramatically increases wear of both chain and sprocket

Solution:

• Renold sprocket teeth are induction hardened to tightly controlled specifications

Benefit:

• Highly resistant to shock loading and faster running applications

'Poor or Inconsistent Tooth Surface Profile'

Problem:

• Prevents smooth running of chain over sprocket, accelerating wear

Solution:

• Renold sprockets ensure consistent, smooth tooth profile

Benefit:

• Reduced wear and quieter operation

Range & Specification

As part of our comprehensive portfolio of sprockets, our new high performance range is initially available, from stock, in pitch sizes 06B to 16B simplex in pilot bore configuration withnew products being added continuously.

• Renold high performance sprockets adhere to the ISO 606 standard and are manufactured fromC45 grade carbon steel


• Teeth are induction hardened to a tight tolerance in the range 40-50HRC


• Products are additionally surface treated to prevent corrosion and improve lubricity

For more information on our FULL range of sprockets click here

Download the sprockets range product data sheet here

Additional Services

Customisation, rebore, keyway & setscrew modification services are available.
Please contact your local sales office.