Mechanical Coupling Specification Example for Long-Haul Trucks: Heavy Duty
Mechanical Coupling Specification Example for Long-Haul Trucks: Heavy Duty
This is a worked specification for mechanical coupling in a heavy duty programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The heavy duty version exists because the duty cycle on long-haul trucks is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually a specification nobody had written down.
Example specification
| Item | Mechanical Coupling |
|---|---|
| Application | Long-Haul Trucks |
| Version | Heavy Duty |
| Base material | PU Leather |
| Controlled dimensions | 3 key dimensions, recorded per lot |
| Tolerance band | ±0.2 mm |
| Finish | anodised |
| MOQ | 200 pieces per specification |
| Sampling | 14 working days, 5 days per revision |
| Compliance | SAE J431 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — PU Leather, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.
Processes involved
- die casting
- cold forging
- assembly line testing
- powder coating
- gravity casting
- anodising
Where this example applies
Programmes that run heavy duty most often specify this build for long-haul trucks. Related applications include municipal fleets, racing teams, scooter fleets, aftermarket retail, passenger cars.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 4.0 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
What testing is included?
Standard lots ship with dimensional and hardness reports. SAE J431 documentation is issued with the shipment when your market requires it.
How is packing specified?
Individual packing, inner box quantity and carton marking are confirmed at quotation stage so the cartons arrive ready for your warehouse.
What is the minimum order quantity?
The standard MOQ is 200 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
How long does sampling take?
Samples leave the factory in 14 working days, and each revision round adds about 5 days once you have seen the first piece.
Ask for the current catalogue and the specification sheet for this line.
