The Advantages of Profiled Timing Belts over Chains

This case study will cover the benefits of profiled timing belts over attachment chains and how we were able to meet and even exceed customer expectations with our ATN Convertible Timing Belt System.

The Problem:

This customer was questioning whether to use attachment chains or timing belts with profiles for a particular application.

The Customer’s Application:

The automated manufacturing of cable trays. The customer’s application is to have the conveyor index forward, as a robot arm loads rungs on the conveyor in various intervals like “ladder steps”.  After all the rungs are placed on the conveyor, the side beams are aligned to the ends of the rungs and then the assembly is welded together.  Keep in mind that there is a welder located at the ends of each rung, and the welding is done in one operation.

Customer Requirements

1. Customer wants to be able to change the spacing of the attachment easily
2. The customer needs to use metal profiles
3. Rungs need to maintain spacing over time
4. Rungs need to be located accurately for the welding process in order to get proper weld
5. The customer’s requirement was that the each rung would align with the welder by +/-0.125 in  (approx. 3.2 mm)
6. They need to minimize life cycle costs

Timing Belt Recommendation

BRECOflex recommended the ATN Convertible timing belt system as having significant advantages over chain. The ATN  Belt Advantages include:

1. ATN belts with punched holes allow for adjustable spacing
2. The customer has the ability to attach their own profiles
3. It guarantees the accurate alignment of welders for the life of the belt over time due to no belt stretch
4. ATN has molded cavities for accurate attachment placing
5. No maintenance/no lubrication /no re-tensioning requires

Chains Vs. Timing Belts with Regard to Elongation Over Time

A chain wears at the pins and links, which causes an elongation of the chain. In order to compensate for the chain stretch over time, the customer will have to frequently adjust the distance between his welding stations. Conversely, BRECOflex high precision polyurethane timing belts will not stretch over time. See the index below:

Rung Placement Accuracy with ATN Timing Belts:

As stated above, the customer requires that the each rung would align with the welder by +/-0.125 in  (approx. 3.2 mm)

• BRECOflex evaluated four different variables:
• 1) belt length tolerance:   +/-0.8 mm per meter of belt – you can compensate for this by adjusting the spacing of the welding stations once at the time of installation
• 2)  Variation of belt:  tolerance within a belt is approximately +/-0.1mm/m
• 3)  Weld zone:  Variation of belt tolerance in the weld area results in the maximum belt length difference of about 0.2 mm
• 4)  Profile location:  accuracy due to punching the ATN hole, tolerances of the profile, and the attachment of the profile is approximately ±0.25 mm

The total belt accuracy, which cannot be compensated for, exceeded the customers requirements.

Conclusion:

In conclusion, the determination is that ATN profile timing belts provide a maintenance-free and cost effective solution for this customer.

• The superior belt tolerance
• the ability to attach the customer’s own profiles
• the absence of issues involved with elongation
• the quieter operation
• and overall extended service life of ATN polyurethane timing belts