KEVOS® MAKEOS · Fasteners
Pivot Pin and Retaining Ring Check (Clevis Stresses and Axial Retention)
Is this clevis pivot pin strong enough for the load, and will the retaining ring that holds it in take the axial push without failing?
Check of a pivot pin in a clevis held in by a retaining ring: pin bending and shear, bearing in the eye and fork plates, net tension and tear-out of the eye, each against your allowable (as the clevis pin joint tool), the thrust capacity of the ring in shear and of the groove in yield with your safety factor and the least groove distance from the pin end (as the retaining ring thrust tool), checked against the axial load and the pin projection you have.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Radial load on the pin | kN | Load carried by the pin across the clevis. |
| Axial load on the ring | kN | Axial force pushing the pin against the retaining ring (side thrust, misalignment). |
| Pin diameter | mm | Pin diameter (also the ring’s shaft diameter). |
| Eye thickness | mm | Thickness of the eye (the middle member). |
| Thickness of each fork plate | mm | Thickness of each fork plate. |
| Gap between eye and each fork plate | mm | Clearance between the eye and each fork plate. |
| Eye edge distance (hole centre to edge) | mm | Distance from the eye hole centre to the eye edge in the load direction. |
| Retaining ring | ||
| Ring type | choice | Kind of retaining ring. |
| Ring thickness | mm | Thickness of the retaining ring. |
| Groove depth | mm | Depth of the ring groove. |
| Groove contact fraction (stamped) | % | Share of the groove circumference a stamped ring bears on. |
| Pin projection beyond the groove | mm | Length of pin from the groove to the pin end. |
| Allowables (your values) | ||
| Allowable pin bending stress | MPa | Allowable bending stress of the pin. |
| Allowable pin shear stress | MPa | Allowable shear stress of the pin. |
| Allowable bearing stress | MPa | Allowable bearing stress of the eye and fork. |
| Allowable eye tensile stress | MPa | Allowable tensile stress of the eye. |
| Allowable eye shear stress | MPa | Allowable shear stress of the eye. |
| Shear strength of the ring material | MPa | Shear strength of the ring material. |
| Yield strength of the pin (groove) material | MPa | Yield strength of the pin material at the groove. |
| Shear strength of the pin (groove) material | MPa | Shear strength of the pin material behind the groove. |
| Ring safety factor | Safety factor on the ring thrust capacity. | |
Method and formulas
- Pin bending moment = F (a + 2b + 4g) ÷ 8; bending, shear, bearing, net tension and tear-out stresses (as the clevis pin joint tool).
- Ring shear capacity = π D t S_s ÷ K; groove yield capacity = π D d_g S_y ÷ K × contact; allowable = the smaller (as the retaining ring thrust tool).
- Least groove distance from the end = K P ÷ (π D S_c).
- Example: the clevis is at 56.023% of its allowables; the ring holds 4.1888 kN axially against 2 kN.
Limitations
- Static loads; reversing loads need a fatigue check of the pin and ring.
- The groove is assumed outside the fork plates, so it does not weaken the loaded pin section.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check a hydraulic cylinder or linkage pivot
- Choose a retaining ring for a pin that sees side thrust
- Set the pin projection beyond the fork
Who it is for
- Design engineers
- Machine designers
- Maintenance engineers
What you get
- Clevis stresses and highest utilisation
- Ring and groove thrust capacity
- Groove distance from the pin end
Interpreting the result
- Side thrust is often underestimated: a misaligned cylinder can push a pin out with a large share of its force.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1535, 1720–1735, 1763–1789. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Pivot Pin and Retaining Ring Check (Clevis Stresses and Axial Retention) calculator
