KEVOS® MAKEOS · Fasteners
Clevis Pin Joint Design (Pin Bending, Shear, Bearing and Eye)
Is this clevis (fork-and-eye) pin joint strong enough: pin bending and shear, bearing in the eye and fork, and tear-out of the eye?
Check of a pinned clevis joint with a central eye between two fork plates: pin bending moment with the load spread over the eye and fork plates and the gaps between them, pin bending stress, double-shear stress (as the bolt and pin shear tool), bearing stress in the eye and in the fork plates, and the eye’s net-section tension and shear tear-out beyond the hole.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Load | kN | Load through the joint. |
| Pin diameter | mm | Diameter of the pin (taken equal to the hole). |
| Eye thickness | mm | Thickness of the eye (the central member). |
| Thickness of each fork plate | mm | Thickness of each of the two fork plates. |
| 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 hole centre to the edge of the eye in the load direction. |
| Allowable pin bending stress | MPa | Allowable bending stress of the pin (your value). |
| Allowable pin shear stress | MPa | Allowable shear stress of the pin. |
| Allowable bearing stress | MPa | Allowable bearing stress between pin and plates. |
| Allowable eye tensile stress | MPa | Allowable tensile stress of the eye. |
| Allowable eye shear stress | MPa | Allowable shear stress of the eye. |
Method and formulas
- Pin bending with the load spread over the eye and fork plates: M = F (a + 2b + 4g) ÷ 8; σ = 32M ÷ (π d³).
- Double shear τ = F ÷ (2 × π d² ÷ 4) (as the bolt and pin shear tool).
- Bearing: eye F ÷ (d a); fork F ÷ (2 d b).
- Eye net tension F ÷ [(2R − d) a]; tear-out F ÷ [2a (R − d ÷ 2)].
- Example: 20 kN bends the 20 mm pin to 140.06 MPa; shear is 31.831 MPa and the eye bears at 50 MPa.
Limitations
- Uniformly spread bearing loads; a tight fit or rigid plates lowers the pin moment.
- Static loads; reversing loads need fatigue checks and a hardened pin.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Size a clevis pin for a cylinder or linkage
- Find why clevis pins bend in service
- Check an eye end for a higher load
Who it is for
- Design engineers
- Hydraulic engineers
- Maintenance engineers
What you get
- Pin bending moment and stress
- Pin shear and bearing stresses
- Eye net tension and tear-out
Interpreting the result
- Pin bending often governs: closing the gaps and keeping the fork plates thin relative to the pin helps most.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1535, 1720–1735. Topic reference; no source tables or recommended settings are reproduced.
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Open the Clevis Pin Joint Design (Pin Bending, Shear, Bearing and Eye) calculator
