trunnion

The mill's large stone wheel rotates smoothly on its heavy iron trunnion.

Definition

1. Noun (countable):
   • A pivoting support: A "trunnion" is a cylindrical projection on each side of a cannon, mortar, or other heavy object, serving as a support and allowing it to pivot or tilt up and down. More broadly, it refers to any similar pin or pivot that enables rotation or articulation in machinery.

Usage Examples

• (The cannon's pivoting supports enabled vertical adjustment.)
• (The pivoting pin of the valve was checked for wear.)
• (The pivot joint allows the telescope to be moved.)

Advanced Usage

• "Trunnion bearing": A bearing that supports a trunnion, often used in heavy machinery like turbines or mills.

  • The trunnion bearing of the cement mill requires regular lubrication. (The bearing that supports the mill's pivot pin needs maintenance.)

• "Trunnion ring": A ring-shaped component that houses or reinforces a trunnion, common in rotary kilns or industrial drums.

  • The trunnion ring on the kiln was replaced after years of thermal stress. (The supporting ring for the pivoting mechanism was swapped out.)

Variants and Related Words

• Trunnioned (adj): fitted with or having trunnions.

  • The trunnioned base of the turret allowed it to rotate smoothly. (The base had pivoting pins for rotation.)

• Trunnionless (adj): lacking trunnions; often used to describe a design without pivoting supports.

  • The trunnionless design of the new mortar simplified its assembly. (The mortar had no pivoting pins.)

Synonyms

• Pivot: a central point on which something turns.
• Gudgeon: a pivot or journal, especially in a hinge or shaft (closely related in mechanical contexts).
• Axle pin: a pin that serves as an axis for rotation.

Related Idioms

Phrasal Verbs