Q&A  Top chain

The following is a list of answers for frequently asked questions from our customers. Select questions to view the answers.

Words 

Top chain

Q1 What types of chain are there?
Q2 How is each type (shape) used?
Q3 How to select the specification (material) of Top chain?
Q4 What is the difference between stainless steel pins and plastic pins?
Q5 How do I select rail material?
Q6 How do I install straight rails?

Plastic Top Chain and Plastic Block Chain

Q7 What are some conveyor designs for top chain and plastic block chain?
Q8 Return way layout for top chain and plastic block chain
Q9 Conveyors using corner discs
Q10 What are some conveyor designs for plastic crescent chain?
Q11 How do I disconnect and assemble plastic top chain and plastic block chain?
Q12 What should I be careful of when using plastic top chain, plastic block chain, and plastic pins?
Q13 Is forward-reverse operation possible with plastic top chain and plastic block chain?

Plastic modular chain

Q14 How do I know when to use plastic modular chain?
Q15 How do I disconnect and assemble plastic modular chain?
Q16 How to install sprockets?
Q17 How about conveyor designs of plastic modular chain?
Q18 Return way layout for plastic modular chain
Q19 Is forward-reverse operation possible with plastic modular chain?
Q20 I need to make a conveyor with a compact transfer area.
Q21 I need to eliminate items remaining when using right-angle conveyors.
Q22 【Plastic modular chain 】The sprockets that can be used with chain with float-preventive Tab.
Answers
Q1 What types of chain are there?
A1

Top chain has three types; "Plastic modular chain" with the belt-like wide conveying surface, "Plastic top chain" with transfer plate, and "Plastic block chain" with block shape and small width.

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Q2 How is each type (shape) used?
A2


<Plastic modular chain >

Wide conveying surface suitable for conveying various types and bulk quantities of items at once. Conveying heavy objects is also possible thanks to its higher allowable load. Suitable for conveying large quantities of containers, wide width items such as packing boxes and sheets, and heavy objects such as tires.


<Plastic top chain >

Ideal for loading and transferring containers, packing boxes, etc. one by one onto the plates. Types with rollers installed on the tops of the plates that can minimize scratching of conveyed items during accumulation are also available. With our largest line-up, users can select from a variety of models to meet their straight/curved conveyance needs, and to match the size and shape of the items they need to convey.


<Plastic block chain >

Perfect for conveying small items such as eye drops with single strand use. Double strands are ideal for conveying pallets, packing boxes, etc. Thanks to its easy maintenance, it is often installed between rollers on a roller conveyor and used to discharge (traverser) conveyed items.

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Q3 How to select the specification (material) of Top chain?
A3

Click on the links below to find out how to select the specification and the applicable table by specification.

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Q4 What is the difference between stainless steel pins and plastic pins?
A4

With its light weight and easy handling, plastic pins are predominant for plastic modular chains and plastic top chains. The use of plastic pins is recommended when there is exposure to water only (adhering to conveyed items from the previous process) since stainless steel pins have a shorter service life when exposed to water.

Stainless steel pins are becoming predominant for plastic block chain. Depending on the product, the allowable load is greater than with plastic pins. Stainless steel pins are recommended when there are impacts on the chain.


with plastic pin

Allowable load roughly equal to stainless steel pins (80% to 100%)
Improvements have been made to the structure of the thick plastic pins and hinges.

Long life: A combination of proprietary Tsubaki materials allows the chain to exhibit outstanding wear resistance between the pin and bushes under dry, soapy water, or wet conditions. The chain works particularly well when using water as the lubricant.

Lightweight: 15% to 25% lighter than stainless steel pin top chains. Easy to handle and effective in reducing noise and required power.

Easy disposal: As the entire chain is made of plastic, it can be disposed of as is.

Conforms to food sanitation regulations: The links and pins are manufactured from materials that are in accordance with Japan's Food Sanitation Act.

Note: Refer to Technical notes, handling of top chain, precaution of plastic pin and disconnection/connection.
2.Operating temperature up to 60℃ is allowed when plastic pin chains are used in wet conditions.

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Q5 How do I select rail material?
A5

When installing plastic chains, rails are generally installed as well to guide the chain. Select the material for your rail based on your application and purpose.

General applications

Rails made of ultra-high molecular weight polyethylene (Plastic rail and plastic rails) are often used. Recommended for use in lubricated conditions.
*Be aware that more wear debris will be generated when used in unlubricated conditions.

Suppresses the generation of wear debris

PMW plastic rails and M plastic rails are recommended. Stainless steel (smoothly polished) and metallic rails (hard chromium finished + buffed top finished) also suppress the generation of wear debris. *M plastic rails must be used under dry conditions. Do not use in contact with water or lube. *Wear debris generated with metal rails (including stainless steel) will be black due to the inclusion of metallic debris.


P Plastic Rails (Code: P)

  • Conventionally used for general-purpose applications; manufactured from UHMW-PE (ultra-high molecular weight polyethylene).
  • Recommended for use with stainless steel chains.
  • When used in combination with plastic chains, it is recommended that they be used under wet (lubricated) conditions. (When used under dry “non-lubricated” conditions, there is the potential for the generation of large amounts of wear dust.)
  • Operating temperature range: -20℃ to 60℃
  • Do not use in environments where rail components will be exposed to steam.
  • Same as standard grade of Plastic rail

PMW Plastic Rails (Code: PMW)

  • Superior wear resistance and low friction (compared to P Plastic Rails).
  • Compared to P Plastic Rails, can reduce amount of wear dust generated to the level of M Plastic Rails.
  • Can reduce coefficient of friction of chain to approximately 20% of P Plastic Rail levels.
  • Operating temperature range: -20℃ to 60℃
  • Do not use in environments where rail components will be exposed to steam.

M Plastic Rails (Code: M)

  • Plastic rail designed specifically for dry conditions (do not use under wet conditions).
  • Especially recommended when generation of wear dust may be a source of problems.
  • Operating temperature range: -20℃ to 80℃

When using in high temperature conditions

Metallic rails are recommended. Use smoothly polished or hard chromium finished + buffed top finished rails.


Use at High Temperature

Recommended wearstrip material is cold-rolled stainless steel.

Secure only one end of wearstrips to allow for thermal expansion. Also, remember to leave a gap between wearstrips to allow for thermal expansion.

(Reference: Coefficient of linear expansion for 304 stainless steel is 1.8 x 10-5 mm/mm/℃)
Example: Securing stainless steel wearstrips, and leaving space between wearstrips

Standard steel sprockets can be used for ambient temperatures below 150℃. Special sprockets must be used at temperatures higher than 150℃. Contact a Tsubaki representative for details.

Spacing between chains when multiple strands are used is shown below.

Take-up must be done to compensate for slack in the chain caused by thermal expansion. Take-up adjustments should be performed after reaching operating temperature. Lower temperatures only after loosening take-up.

Black wear dust will be generated. Be sure to clean on a regular basis.

Start up slowly (using inverter control) and stop slowly.


<Wearstrip Material Selection Guide >
Chain Type Wearstrip Material No lube With lube
Abrasives
Without yes Without yes
Stainless steel top chain
・Straight running
・Side flexing
Stainless D D B B
steel D C B A
Plastic rail
(P plastic rail)
PMW plastic rail
A × A ×
M plastic rail
SJ-CNO
A × × ×
Plastic top chain,
plastic block chain,
plastic modular chain
・Straight running
・Side flexing
Stainless B D A A
steel A C D D
Plastic rail
(P plastic rail)
D × A ×
PMW plastic rail B × A ×
M plastic rail
SJ-CNO
A × × ×

A: Most recommended
B: Highly recommended
C: Recommended
D: Acceptable
×: Inappropriate

Note)

1.Refer to “No lube” for Lambda chains.

2.Select stainless steel or steel wearstrips for KV series chains (heat resistant, high speed) for normal temperatures, and a stainless steel wearstrip for high-temperature applications.

3.Recommended metallic wearstrip is cold-rolled steel.

4.The recommended lubricant for steel rails is oil.

  Material, Color Features
Plastic rail
(P plastic rail)
  • Ultra high molecular weight polyethylene
  • White or green
  • Most commonly used rail
  • Machined or extruded
  • Recommended for plastic chains used under wet conditions
  • Low water absorption; chemical and impact resistance are also excellent
PMW plastic rail
  • Low friction, wear resistant UHMW-PE
  • White
  • Lower friction and more wear resistant than P plastic rail
  • Machined
M plastic rail
SJ-CNO
  • Special polyamide
  • Blue (M plastic rail),
    gray (SJ-NCO)
  • Speci?cally designed for dry use
  • Wear resistant
  • Machined

Note: Operating temperature range

Plastic rail (P plastic rail), PMW plastic rail: -20℃ to 60℃

M plastic rail, SJ-CNO: -20℃ to 80℃


Back to questions
Q6 How do I install straight rails?
A6

When using plastic straight rails, leave a suitable gap between wearstrips to allow for thermal expansion. Also, secure only one end of the wearstrips.


Tongue and groove wearstrips (PR, PH), flat wearstrips

  • Use a screw to attach only one end of the wearstrip to the frame and leave an appropriate gap at the joint to allow for thermal expansion.

Gap between tongue and groove wearstrips … 3 to 5 mm

Coefficients of linear expansion

Plastic rail (P plastic rail)
PMW plastic rail 20×10-5mm/mm/℃

M plastic rail 9×10-5mm/mm/℃

Note)

1.Operating temperature range

Plastic rail (P plastic rail), PMW plastic rail: -20℃ to 60℃

M plastic rail: -20℃ to 80℃

2.Do not use in environments where rail components will be exposed to steam.


Mounting long straight wearstrip (extruded wearstrips such as Z, T, L, and flat) when the conveyor length is long

  • Assuming that these wearstrips are installed in 1-meter units, a gap should be left between wearstrips to prevent chain sag as shown in the illustration below.


Gap between long straight wearstrips … 10 mm per meter


Mounting long straight wearstrip (extruded wearstrips such as Z, T, L, and flat) when the conveyor length is short

  • If both ends of the wearstrip are secured using small flathead screws, the wearstrip will warp (become rippled) due to the difference in coefficient of thermal expansion between the wearstrip and metal frame. Attach only one end of the wearstrip using a small flathead screw.


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Q7 What are some conveyor designs for top chain and plastic block chain?
A7

Generally, for plastic chain, the wearstrip should support the chain on the carry way, and the chain should be slack on the return way. Chain slack below the drive sprocket is especially important. Ensure there is 50 - 100mm of slack for 500 - 900mm spans (in drive operations). Tooth jumping (skipping) may occur with other slack values.


The layout of the supports for chains will vary according to the installation space available and other parameters. A typical layout is shown below. See Question No.8 for the layout of the return way of the chain.

Chain slack

Return rollers should be spaced at intervals of 500 to 900 mm to support the return way of the chain. The amount of slack in the chain between return rollers should be 50 to 100 mm. This slack prevents tooth jumping (skipping). Tooth jumping may occur when the amount of slack in these intervals falls outside of this range.

Engagement angle

The engagement angle between the drive sprocket and the chain must be greater than 150°.

Wearstrip ends

A distance equivalent to the pitch spacing of the chain must be established between the end of the wearstrip and the respective shaft centers on both the drive and driven ends. Also, the tail end of the return wearstrip on the driven side must be rounded or chamfered (sloped) to prevent catching or snagging of the chain on the wearstrip.

Height of carry-way wearstrip

Refer to Technical notes, conveyor design, rail mounting on drive/driven side.

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Q8 Return way layout for top chain and plastic block chain
A8

As the most common layout, we recommend supporting your chain with return rollers. Supporting with return roller enables to you to set an applicable chain slack and absorb elongation. When using chains with float-preventive tabs, you can also support the chain through the sliding action of the tabs. However, consider using a system (such as a tensioner) to absorb chain elongation.
Other options include using a guide rails and wearstrips, using glide shoes, using guide rails only, no support on return way, etc. Be aware that not supporting the return way may cause vibration and prevent smooth operation.


The return-way layout will vary according to the type of chain, the type of goods being conveyed, the flow system and route topology, but in general, layouts will be similar to those illustrated below.


[Click to enlarge ]

Supported by return rollers

This is the most common and recommended layout.

  • Angle of chain wrap on the drive sprocket must be at least 150°.
  • Make sure the return rollers rotate freely. If they do not rotate freely, localized sliding will occur, possibly generating wear dust or causing the top plate to wear unevenly.High-rotation return rollers or return rollers with integrated bearings are recommended for the return rollers.
  • For chain speeds greater than 50 m/min, dimension C must be less than 300 mm.

A: 50 to 100 mm (during operation)
B: 500 to 900 mm
C: 400 to 600 mm
D: Less than half the outer diameter of sprocket
May vary depending on chain type and conveying conditions. To be used only as a basic guide.


※Refer to the technical notes in the catalog for details.


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Supported by wearstrip fitted with float-preventive tabs

Using a wearstrip to support chains fitted with float-preventive tabs eliminates sliding on the top plate surface. This is particularly applicable in situations where damage (such as scratching) to the top plate’s upper surface must be avoided during conveying.

  • Angle of chain wrap on the drive sprocket must be at least 150°.

A: 50 to 100 mm (during operation)
B: 500 to 900 mm
May vary depending on chain type and conveying conditions. To be used only as a basic guide.


※Refer to the technical notes in the catalog for details.


[Click to enlarge ]

Supported by serpentine-style wearstrip

Supporting the top plates only in localized areas may result in uneven wear. Install the rail in an “8”-shaped or wavelike layout so that the top chain plates are fully supported at all points. The construction should be such that extraneous matter, dirt, etc., falls through easily.

  • Angle of chain wrap on the drive sprocket must be at least 150°.

A: 50 to 100 mm (during operation)
B: 500 to 900 mm
May vary depending on chain type and conveying conditions. To be used only as a basic guide.


※Refer to the technical notes in the catalog for details.


[Click to enlarge ]

Supported by sliding shoes

Suitable for relatively slow-speed conveying conditions (less than 50 m/min). Generally used for accumulation chain (TTPDH-LBP) or roller tables (ST/RT).

  • Angle of chain wrap on the drive sprocket must be at least 150°.

A: 50 to 100 mm (during operation)
B: 500 to 900 mm
C: 400 to 600 mm
May vary depending on chain type and conveying conditions. To be used only as a basic guide.


※Refer to the technical notes in the catalog for details.


[Click to enlarge ]

Using guide rails only

Although this is an economical option for layouts, it has a disadvantage in that the upper surface of the top plates is susceptible to damage from sliding. Suitable for chains with relatively large back-flex radius.

  • Angle of chain wrap on the drive sprocket must be at least 150°.
  • The radius of curvature (R) on both ends of the guide rails must be greater than the back-flex radius of the chain.
  • ※Refer to the technical notes in the catalog for details.

A: 50 to 100 mm (during operation)
B: 500 to 900 mm
May vary depending on chain type and conveying conditions. To be used only as a basic guide.


[Click to enlarge ]

No support

This conveyor layout is normally not recommended because the tension of the return way from the weight of the chain causes chain vibration and prevents smooth operation. If this method is navoidable in the case of short conveyor lengths (less than 1.5 m), provide a take-up mechanism on the driven side or splice the chain in case the chain elongates. The wrap angle on the drive sprocket must be at least 150°.

  • The amount of chain slack A should be approximately 10% of the conveyor length B.
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Q9 Conveyors using corner discs
A9

For chains with a small sideflex radius (minimum sideflex radius (under R190)), install a corner disc when manufacturing a conveyor with a small sideflex radius. A corner disc should be installed at the center of the sideflex radius for the conveying surface and return way sides.


Curved Section Using Corner Disc on TPUSR Chain

Explanation of symbols

  • R: Sideflex radius of chain (mm)
  • R1: Outer radius of corner disc (mm)
  • R2: Inside radius of wearstrip for outside of chain (mm)
  • R3: Inner circumference of conveyor frame used to secure outside wearstrip (mm)

As shown in the figure below, for chains supported by return rollers, rollers must be installed to guide the straight portion of the return-way chain at the point where the chain enters and exits the corner.

Note: Use in a dry environment is recommended.

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Q10 What are some conveyor designs for plastic crescent chain?
A10

Plastic crescent chain is designed for use in horizontal conveyors. For TORP types with rollers, guide the chain with a sprocket or wearstrip at the corners. For TORP types without rollers, use sprockets at the corners. For horizontal conveyance, a take-up mechanism must be installed to absorb elongation resulting from temperature changes or wear elongation of the conveyor. Without one, tooth jumping (skipping) can occur.


Wearstrip layout

Layout will vary depending on the installation space, but the following examples can be used for reference.


Wearstrip layout example 1 … Using TOSP1143 and corner sprocket


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Wearstrip layout example 2 … Using TORP1143 and corner sprocket


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Wearstrip layout example 3 … Using TORP1143 and curved wearstrip


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Precautions on conveyor layout

A take-up mechanism must be installed to absorb elongation resulting from temperature changes or wear elongation of the conveyor. See example below for reference.

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Q11 How do I disconnect and assemble plastic top chain and plastic block chain?
A11

Connecting pins differ by type. Disassemble, cut, or connect with a punch and hammer suited to the shape of the connecting pins. Only plastic crescent chain has a unique structure. See below for further information.


When D-pins are used (except TPUN555)

The chain can be disconnected at any link and the pin can be removed from either the left or the right.

When knurled pins are used

To disconnect, place a punch on the end of the connecting pin on the side that is not knurled and lightly tap it with a hammer to remove it. To reconnect, place a punch on the end of the connecting pin on the knurled side and lightly tap it with a hammer to insert it.(For TTPDH and TTPDH-LBP only, the knurled side is inserted from the same side even for reconnecting.)

For TN, TNU, TRU, TP-1873T

The pin for the connecting link is loosely fitted on the appropriate side of the outer plate. When disconnecting the chain at links other than the connecting link, remove a pair of pins parallel to one another by means of a chain vice. Once a chain is disconnected at links other than the connecting link, the link cannot be reused.

When D-pins are used (except TPUN555)

Pin insertion direction is from one direction only. Place a punch on the opposite end of the pin from the insertion direction, and tap it lightly with a hammer to remove it.

For Plastic Crescent Top Chain

1.Remove the snap cotter pin from the connecting pin, and carefully pull the offset link up and off.

2.Turn the offset link 90 degrees.

3.Remove the main link and the connecting pin from the previous link.

Note: When disconnecting, be sure not to pull the connecting pin out of the main link.

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Q12 What should I be careful of when using plastic top chain, plastic block chain, and plastic pins?
A12

Once removed, pins should not be reused to prevent a reduced push out force and other problems with pins falling out. The disassembling pin is colored orange so as to distinguish it from base-chain pins (colored white). Use the disassembling pin included with chain when cutting. Avoid use in wet environments where temperatures exceed 60℃. Pin may break.

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Q13 Is forward-reverse operation possible with plastic top chain and plastic block chain?
A13

The direction of plastic top chains and plastic block chains is set. Forward-reverse operation is not recommended. If considering forward-reverse operation, consider using plastic modular chains.

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Q14 How do I know when to use plastic modular chain?
A14

We recommend WT1500 series, BTN5, BT6, BTC4-M, and TOD type chains with small chain pitches for reducing the size of your conveyor transfer areas. For general applications, we recommend BT8, WT2250, WT2706, WT3835 and WT300 chains. For higher applied loads and conveying heavy objects, we recommend WT2500 and BTH16 series chains. For eliminating gaps in connecting areas, we recommend WT1907, 3827, 5707 series chains. Try magnet-embedded BTM8H and BTM8H-M chains for inclined conveyance of metal trays and parts (to prevent slipping). We recommend BTC8S for conveying cardboard boxes. For inclined conveyance, we also recommend WT2250 series with attached flights and rubber pads.

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Q15 How do I disconnect and assemble plastic modular chain?
A15

The structure of each chain series differs. See below for further information.


■Structure and Disconnecting/Reconnecting of the BTN5, BT6, and BT8 Series

Structure of both ends of chain

A snap attachment is inserted in the link from the underside of the link at each end of the chain to prevent the pin from coming out (snap fit).


[Click to enlarge ]

Procedure for disconnecting and reconnecting

1) Insert a small flathead screwdriver into the gap (about 1mm) between the link hole and the snap attachment to detach the snap attachment.


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2) Use a threaded head screwdriver and screw it into the center hole (1.0mm dia.) of the pin and pull out the pin to disconnect the chain.


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3) When connecting the links of a chain, bring both ends of the chain together and insert the pin in the hole from one side. Finally, insert the snap attachment from the underside of the chain. Make certain that the snap attachment does not protrude from the bottom of the link.

 

■Disconnecting the WT1500/3000 Series

1) Insert a small flathead screwdriver or similar tool between the chain and the plug-clip on the side of the chain.


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2) Using the screwdriver as a lever, pry out and remove the plug-clip from the base chain. Work carefully so that the plug-clip does not pop out and fly off.


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3) Use a threaded head screwdriver and screw it into the center hole (1.0mm dia.) of the pin and pull out the pin to disconnect the chain.


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■Reconnecting the WT1500/3000 Series

1) When reconnecting the links of a chain, bring the ends of the two chains together, interlace the links, and insert the connecting pin from one side.


[Click to enlarge ]

2) Then re-insert the plug-clip to cover the insertion area. At this point, check the orientation of the plug-clip (make sure that the protrusion is going into the pin hole), and seat the plug-clip by pushing in until you hear it click into place.


[Click to enlarge ]

3) Check that the plug-clip is properly installed.


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Note: When reconnecting chain links, be sure to use the pins provided or special pins.


■Disconnecting the WT2500 Series and BTM8H Series

1) Insert a small flathead screwdriver or similar tool into the hole in the plug on the side of the chain.


[Click to enlarge ]

2) Push the screwdriver in the direction of the arrow to slide the plug to the side.


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3) Use a threaded head screwdriver and screw it into the center hole (1.0mm dia.) of the pin and pull out the pin to disconnect the chain.


[Click to enlarge ]

Note: The shape for BTM8-M is different.


■Reconnecting the WT2500 Series and BTM8H Series

1) When reconnecting the links of a chain, bring the ends of the two chains together, interlace the links, and insert the connecting pin from one side.


[Click to enlarge ]

2) Slide the plug to the side to cover the insertion area.


[Click to enlarge ]

Note: The shape for BTM8-M is different.

Note: When reconnecting chain links, be sure to use the pins provided or special pins.


■Disconnecting the WT3800 Series

1) Insert a small flathead screwdriver or similar tool between the chain and the plug-clip on the side of the chain.


[Click to enlarge ]

2) Push the screwdriver in the direction of the arrow to slide the plug to the side.


[Click to enlarge ]

3) Use a threaded head screwdriver and screw it into the center hole (1.0mm dia.) of the pin and pull out the pin to disconnect the chain.


[Click to enlarge ]

■Reconnecting the WT3800 Series

1) When reconnecting the links of a chain, bring the ends of the two chains together, interlace the links, and insert the connecting pin from one side.


[Click to enlarge ]

2) Slide the plug to the side to cover the insertion area.


[Click to enlarge ]

Note: When reconnecting chain links, be sure to use the pins provided or special pins.


■Disconnecting and Reconnecting BTC-4M and BTO8-M

1) Disconnecting

・Place a punch (2.5mm dia. or smaller) on the outer edge of the D-pin on the D-hole side of the link and lightly knock the punch with a hammer to remove the pin.

・Or, the pin can be removed using a small flathead screwdriver from the stopper side.


[Click to enlarge ]

2) Connecting

・Use the exclusively prepared D-pin (colored orange).

・Make certain that the D-pin is facing the correct direction and insert it into the chain link.

・Push by a finger or lightly knock by a hammer the stopper of the D-pin.

3) Reconnecting

・Do not cut the chain where a connecting D-pin (colored orange) is already inserted.


・Connecting D-pin

1) Use the exclusively prepared D-pin to connect the chain links.

2) The connecting D-pin is colored orange so as to distinguish it from base-chain pins (colored white).

3) One connecting D-pin is provided per chain.


■Structure and Disconnecting/Reconnecting of the WT2250 and BTC8S Series

Structure of both ends of chain

A snap attachment is inserted in the link from the underside of the link at each end of the chain to prevent the pin from coming out (snap fit).


[Click to enlarge ]

Procedure for disconnecting and reconnecting

1) Insert a small flathead screwdriver into the gap (about 1mm) between the link hole and the snap attachment to detach the snap attachment.


[Click to enlarge ]

2) Use a threaded head screwdriver and screw it into the center hole (1.0mm dia.) of the pin and pull out the pin to disconnect the chain.


[Click to enlarge ]

3) When connecting the links of a chain, bring both ends of the chain together and insert the pin in the hole from one side. Finally, insert the snap attachment from the underside of the chain. Make certain that the snap attachment does not protrude from the bottom of the link.


[Click to enlarge ]


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Back to questions
Q16 How to install sprockets?
A16

For wide plastic modular chains, be aware that the number of sprockets and installing positions will differ depending on chain width and tension rate. A sprocket's square or hexagonal bore will be finished larger that the corresponding shaft to handle expansion and contraction with changes in temperature and move freely laterally.


Determine Sprocket Locations

The diagrams below show the location and distance between prockets (pitch) for each type of chain. Find the percentage of maximum allowable load (maximum allowable load per 1 meter of chain width) that the tension per 1 meter of chain width F’ derived by means of formula (2) represents. Note that the locations and pitch may change depending on chain tension rate F1.

Formula of chain tension rate F1 (%)


F’…Tension applied per 1 meter of chain width derived by formula (2) [kN (kgf)]
A …Maximum allowable load per 1 meter of chain width with given temperature [kN (kgf)]

Wide type

1. BTN5, BTN5-A 2. WT1505-K, WT1505G-K, WT1506-K


[Click to enlarge ]


Note: A sprocket with 24 teeth cannot be used with BTN5-A (with tab guide attachments). A sprocket with 32 teeth should be used.


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3. WT1505GTO-K 4. WT2505-K, WT2506-K, BTM8H


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5. WT3005-K/WT3005G-K 6. WT3086-K/WT3086G-K


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7. BT6, BTC8, BTC8-A

・Sprocket locations when chain tension rate (F1) is 50% or less

8. BT6, BTC8

・Sprocket locations when chain tension rate (F 1) greater than 50%.


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9. BTC8-A

・Sprocket locations when chain tension rate (F 1) greater than 50%.

10. WT3816K


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11. WT2250FT, FG 12. BTC8S


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Mold-to-Width type

1. BTC4-500-M

2. BTO8-830-M

3. BTC8H-M/BTM8H-M 4. WT1505G-M300


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5. WT1505GTO-M300 6. WT1505GTO-M600 7. WT2505-M325/G-M325 8. WT2505-M450/G-M450


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9. WT3005G-M300 10. WT3005G-M450 11. WT3086G-M85 12. WT1515G-M50


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Handling Sprockets

In general, square shafts are recommended for the drive and driven shafts used with plastic modular chain, except for special cases. Because changes in temperature will cause the chain to expand and contract, sprockets must be mounted so that they are free to move laterally in the across-the-width direction. However, to prevent meandering (snaking) of the chain, one (or two) sprocket(s) should be locked in position in the center of both the drive and driven shafts using setscrews or set-collars and hexagonal socket head cap screws. When installing the sprockets on the square shaft, the inscribed markings or identification marks should be used to orient the sprockets so that they all face the same direction and to keep the position of the teeth aligned.


■Phase Matching of Sprockets

Install the sprockets on the shaft in such a manner that the direction and the position of all the inscribed markings or identification marks on the sprockets are aligned.

  
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■Chain Expansion/Contraction

Plastic modular chain is made of polymer resin, and will expand and contract with changes in temperature. A rough estimate for linear chain expansion is 15×10-5 (/℃) using 20℃ as the reference temperature. The expansion per nominal width (⊿W) is found using the following formula:


⊿W = chain nominal width × (operating ambient temperature-20) ×15×10-5

(Example) For K60 chain (1,524mm wide) used in an environment where the temperature rises from 20℃ to 60℃:

⊿W=1524× (60-20) ×15×10-5 =9.1mm

■Locking Sprockets

The sprockets and the shaft are loosely fitted in order to absorb differences in thermal expansion between the chain and the conveyor and also installation errors of the chain and the sprockets. However, a setscrew, a hexagonal socket head cap screw, or a set-collar should be mounted on each side of a sprocket installed around the center with about 0.5mm (1.6mm for WT) clearance with the sprocket in order to prevent winding motion in the chain.


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Note: Fix the sprocket to be installed between the tab guide attachments when using a chain equipped with tab guide attachments.

■Chain Installation

Wind the chain onto the sprockets installed at the given intervals (refer to the “Chain Selection” section).

If the sprockets are installed at the wrong interval, the chain may run over the sprocket and break. Make certain of the center distance between the sprockets.

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Q17 How about conveyor designs of plastic modular chain?
A17

Generally, for plastic chain, the wearstrip should support the chain on the carry way, and the chain should be slack on the return way. Chain slack below the drive sprocket is especially important. Ensure there is 50 - 100mm of slack for 500 - 900mm spans (in drive operations). Tooth jumping (skipping) may occur with other slack values. Also, wearstrip installation on the conveying surface side will differ depending on the width of the chain, the presence of tab guide attachments, and Mold-to-Width chains.


Wearstrip layout

The layout of the supports for chains will vary according to the installation space available and other parameters. A typical layout is shown below.

Note: The wearstrip of the drive sprocket section and the end of the frame should be chamfered to prevent interference.


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Chain slack

Table 1 shows the spacing L between return rollers supporting the chain on the return way below the drive sprocket. The amount of slack in the chain between return rollers should be 50 to 100 mm. This slack prevents chain teeth jumping. There is a possibility of chain teeth jumping if the amount of slack is outside this range.

Return Roller Spacing L   (Units: mm)
Chain Type Chain tension rate (F1)
50% or less More than 50%
BT6, BT8 500~700 800~1000
WT2250, BTC8S 600~900
WT1500, 2500, 3000, 3800 450~500

Note)

1.Refer to the technical notes in the catalog for Mold-to-Width chains.

2.For pasteurizers and other special conveyors, contact a Tsubaki representative.

3.Refer to the catalog technical notebook for installation of the nose bars at both ends.


Engagement angle

The engagement angle of the chain on the drive sprocket should be at least 180°. If the angle is small, teeth jumping may occur.


Wearstrip ends

A distance C equivalent to the pitch spacing of the chain should be provided between the sprocket and the end of the wearstrip. In addition, the end of the driven-side wearstrip should be rounded or chamfered to prevent the chain from snagging or catching on the wearstrip.


Location of Sprockets and Wearstrips

See illustration below.


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Example of Wearstrip Installation (at Ambient Temperature)

Wide Types (without Tab Guide Attachments)

Wearstrips should be located at equal intervals alternating with sprockets. Wearstrip spacing A is 76 mm for BTN; 76.2 mm for BT6, BT8, WT1500, WT3005, and BTC8S; 76.2 mm for WT2500 (wearstrip width of 25 mm); 85 mm for WT3086 and WT2250; and 100 mm for WT3816 (wearstrip width of 30 mm).


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Wide Types (with Tab Guide Attachments)

(Chains with tab guide attachments: BTN5-A, WT1505GK, WT1505GTOK, WT3005GK, and WT3086GK)

Tab guide attachments (to prevent meandering) should be installed so as not to interfere with the wearstrip.


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A Dimensions
Chain A(mm) Chain A(mm)
WT1505G 44 BTC8-A 44
WT1505GTO 47 WT3005G 44
BTN5-A 44 WT3086G 44

Mold-to-Width Types (with Tab Guide Attachments)

Refer to the table below for guide clearance for chains with guides.Leave a clearance of around 1 mm between chains when used in multi-strand conveyors.

Chain A(mm)
WT1505GM44
WT1505GTOM47
WT1515GM31
WT2505GM45
WT3005GM44
WT3086GM44
BTO8-M44
BTC8H-M44
BTM8H-M44


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Back to questions
Q18 Return way layout for plastic modular chain
A18

As the most common layout, we recommend supporting your chain with return rollers. Supporting with return roller enables to you to set an applicable chain slack and absorb elongation. When using chains with flights, you need to ensure that the flights and rollers do not interfere with one another. Other options include using a wearstrip.


Conveyor Layout

There are two methods of supporting the return way: the return roller system, and the wearstrip system. Examples are shown below.

Precautions:

1.The infeed section of the return wearstrip should be made with a large radius of at least R40.

2.Cut the chain so that the catenary section will have an appropriate amount of slack to compensate for expansion and contraction caused by temperature changes. A tensioner or similar device should be used to adjust the chain take-up.


Supported by return rollers

Conveyor side view


Refer to the technical notes for L dimensions.
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Conveyor plan view


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The center distance of the rollers (in the direction of the conveyor width) should be adjusted according to the width of the chain to be used.


Supported by serpentine-style wearstrip

Conveyor side view


Refer to the technical notes for L dimensions.
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Flight Chain Return Way

The return way of a chain with attached flights or rubber carriers should be set up as shown below so that the flights do not interfere with rollers.


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Note: For wide chain, rollers should be positioned at 765-mm intervals.

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Q19 Is forward-reverse operation possible with plastic modular chain?
A19

Plastic modular chains are suitable for forward-reverse operation. See below for examples.



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Because a load 1.5 times the operating tension acts on the idler roller section in forward/reverse bottom drive, for wide machine width conveyors (greater than 1 m), either select a shaft that has adequate rigidity, or support the shaft using three-point mounting.

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Q20 I need to make a conveyor with a compact transfer area.
A20

Using a nose bar can help you reduce the size of your transfer areas. See further information on BTC4-M chains, which can also provide the same function.


Layout of Abutting Nose Bars

The layout of the supports for chains will vary according to the installation space available and other parameters. A typical layout is shown below.


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Note: 1. Indicated dimensions are just for information, so finely adjust them depending on transfer conditions of the conveyed goods.

Note: 2. Even slight jerking due to the unstable shape of conveyed goods may cause trouble. Contact a Tsubaki representative when such goods have to be conveyed or chain jerking must be avoided.



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The use of WT1500 series or BTN5 chain allows layouts in which two conveyors connect head-to-tail. The width of the dead-plate used in the space where the two conveyors abut can be as small as 20 mm.

Note)

1.The dead-plate gap (marked with ※ in illustration above) will need to be adjusted depending on the objects being conveyed.

2.Applicable chains are the WT1500 series and BTN5 only. It should be noted that WT1505G cannot be adapted to this kind of layout.


Layout of Abutting BTC4-M Chains

For straight transfer with 10T sprockets


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For straight transfer with 18-mm-dia. shafts


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Note: The height level of the dead-plate should be finely adjusted according to transfer conditions of the conveyed goods.

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Q21 I need to eliminate items remaining when using right-angle conveyors.
A21

We recommend using a TOD or GTO type chain that has an integrated transfer area. See below for layout and other information.


Layout of Right-Angle Transfers

A combination with WT1505GTO enables right-angle transfer of goods without using a dead-plate.


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Discharge Conveyor (WT1505GTO/WT1500)


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Note: Dimensions marked with * will need to be adjusted depending on the objects being conveyed.


Using Tsubaki nose bars or GTO type chains enables right-angle transfer of goods without the use of the dead-plate that is usually necessary.


Right-Angle Transfer with WT1500 and WT1505G

Insertion Conveyor (WT1500/WT1505G/WT1515G)


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Note: Dimensions marked with * will need to be adjusted depending on the objects being conveyed.


Discharge Conveyor (WT1500/WT1505G/WT1515G)


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Note: Dimensions marked with * will need to be adjusted depending on the objects being conveyed.

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Q22 【Plastic modular chain 】The sprockets that can be used with chain with float-preventive Tab.
A22

■WT1515T-F-W & WT1516T-F-W: chains with float-preventive Tab

Available Sprockets WT-SW1500-24T, WT-SW1500-32T, WT-SW1500-33T

※Available because there is no interference between float-preventive Tab and the shaft.


■Image Diagram

  
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■Molded Sprocket

  
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■Finish Sprocket

  
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Sprockets not acceptable WT-N1500-12T, WT-N1500-18T

※Refer to the illustration and explanation below for the reason.


■WT-N1500-12T

Cannot be used because float-preventive Tab interferes with the key.

  
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■WT-N1500-18T

Cannot be used because float-preventive Tab interferes with the key, even though there is no interference between Tab and shaft.

  
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