Generally, linear movement or large radius rotation is made possible by a roller chain and gear through a transmission source (motor, etc.) via a reducer.

A roller chain, however, needs a lot of space, and gears require precision machining, which increases the cost.

A pin gear is ideal in these situations.

For pin gear drives, a roller chain is wrapped around the perimeter of a drum to make a wheel, and special sprockets are used instead of pinion gears.

For linear motion, a roller chain is attached and used linearly instead of a rack.

• 1. Economical at large speed ratios (1:5 or larger), especially when the drum has a large diameter.
• 2. Roller chain attachments are bolted onto the drum for easy installation and maintenance.
• 3. Design freedom in drum diameter, linear length, etc.
• 4. A pin gear is not suitable for ultra precision drives, and the noise level is high compared to gears. However, they do not require high installation accuracy nor precision machining as with gears.
• 5. Grease lubrication can be used.

1. When used linearly (rack) with rollers facing up:

Use standard roller chain

Connecting links are used on both ends, and fittings are attached and bolts and nuts are fastened to remove any slack. Both ends need to be secured snugly with double nuts.

Do not use a rail for the rollers, as the teeth of the pin gear sprocket may interfere with the rail.

Using RS roller chains is not recommended as tooth slipping and interference can occur.

Use an attachment roller chain

Attach K1 or SK1 attachments every 2nd link and fasten with bolts and nuts every 2nd or 4th link with chain pulled taut so there is no slack or meandering. K attachments are recommended.

The attachment holes are processed on-site.

Note)  Do not use a rail for the rollers when using SK1 attachments, as the teeth of the pin gear sprocket may interfere with the rail.

Use bolts with a strength class 8.8 or higher (JIS B 1051 : 2014, nominal tensile strength 800 MPa or higher).
(SCM435 heat treated bolts, etc. )

Note)  Chain length should be designed to be longer than the travel distance to accommodate overrun based on usage conditions.

2. When used linearly (rack) with rollers facing down

Attach K1 or SK1 attachments every 2nd link and fasten with bolts and nuts every 2nd link with chain pulled taut so there is no slack or meandering. Do not use a rail for the rollers.

3. When wrapped partially or totally around the outside of a drum

• ・Attachment chain length is in the range of -0.05 to 0.15% of standard length (nominal pitch x number of links). When the chain is wrapped around a drum, shims need to be used between the drum and the chain attachments to eliminate slack.
• ・Since K attachments can be adjusted with shims, they can be attached onto the drum more easily than SK attachments.
• ・When the drum is not perfectly round, the thickness of the shims needs to be adjusted while the chain is wrapped around the drum so the radius is circular.
  As shown to the right, a dial gauge or a surface gauge can be used for adjustment.
• ・Process drum-side tap holes to fit the holes of the chain attachments.

4. When wrapped partially or totally around the inside of a drum

• ・The sprockets have specially shaped teeth. Contact a Tsubaki representative.

5. When used for lateral wrapping (horizontal drive)

• ・See section 3.
• ・Contact a Tsubaki representative for internal fits.

6. Sprocket attachment

• ・Use a chain-type pin gear sprocket.
• ・Adjust the sprocket mounting shaft so that unwanted strong contact with the sprocket tooth face does not occur.
  RS curved chain will make contact with the sprocket tooth face because the chain bends sideways.
• ・The clearance α between the rollers and the bottom of the sprocket teeth should be less than the dimensions shown in the right table.
  The bottom of the teeth and rollers should not touch each other.
• ・If there is a possibility that the clearance mentioned above cannot be guaranteed during operation due to drive or environmental conditions, a tooth profile design having a large α will be required. Contact a Tsubaki representative.

Chain size	α
RS80 or less	1.0mm
RS100～RS180	1.5mm
RS200 or more	2.0mm