Let the route breathe. Keep the load controlled.
An external spring architecture for long-reach duties where the cable route must absorb extension and rebound without being pulled tight or allowed to sag into the process.
An external spring architecture for long-reach duties where the cable route must absorb extension and rebound without being pulled tight or allowed to sag into the process.
The series number is a routing decision, not a product grade. Start with the motion and environment, then let the model, bundle and service access narrow the geometry.
Start here when — and stop when.
Good starting point
- The robot has a large working envelope and the route must compensate changing length.
- A fixed-length package would be pulled tight at extension or sag at retraction.
- The duty benefits from automatic tension instead of frequent manual adjustment.
- The environment is mainly dust or ordinary oil, without heavy spatter or impact.
Not the first answer
- The outer layer sees heavy welding spatter; combine with Series 4 protection or review the barrel route.
- The spring is being treated as a universal anti-vibration part rather than a stroke solution.
- The envelope is too tight for the required spring travel; review Series 5.
- Cable weight and anchor load have not been included in the check.
Specification boundary.
| Conduit diameter (ID / OD) | φ29 (φ34.5) / φ36 (φ42.5) / φ48 (φ54.5) / φ70 (φ80) mm |
|---|---|
| Connector protection | IP54 |
| Body material | PA12 conduit + external return spring |
| Stroke | Large adaptive travel; matched to the measured envelope |
| Typical duties | Handling, palletising, machine tending, FDS, SPR, finishing and long-reach assembly |
| Fixing basis | J3/J4 anchor direction, spring envelope and full extension/retraction path |
| Project release | Travel calculation, spring selection, anchor check, drawing and BOM |
Three things the drawing has to answer.
Keep the spring outside the bundle.
The external spring carries the return load and stores length; it should not press directly into the cable bundle.
Match travel to the real envelope.
Use maximum extension and minimum retraction from the full robot path. A longer spring is not automatically a better spring.
Design the fixed point.
The J3/J4 anchor direction and local stiffness determine how the spring load enters the robot, not just where the bracket fits.
Five checks before a drawing is released.
Step 01
Record the robot model, maximum extension, retraction and cycle frequency.
Step 02
Weigh the cable/hose bundle and tool-side attachments.
Step 03
Confirm J3/J4 fixing points and the available spring envelope.
Step 04
Check compressed length, return margin and minimum bend radius at both ends.
Step 05
Trial-fit and inspect for tension, stacking, rubbing or body collision.
When this series is not enough.
Series 3 solves length change and rebound. It does not replace a spatter shield. In a severe welding environment, review the combination with Series 4 and make the spring and sliding areas cleanable.
Ask before you commit.
Can the spring pinch the cable?
The design must keep the cable bundle separated from the spring and control bend radius through the full stroke. Check the compressed limit during trial fit.
Series 3 or Series 5?
Series 3 is the starting point for large stroke and heavy compensation. Series 5 is for compact storage in a tight envelope.
Does the spring need maintenance?
Yes. Include corrosion, deformation, noise and return-force checks in the inspection plan; frequency depends on dust, oil and cycle rate.
How is travel calculated?
From the complete robot motion envelope, with installation and maintenance margin. Static teach points are not enough.
One model. One envelope. One useful answer.
If the robot code is known, we can skip the generic kit conversation and start with the interface.