Excavator links refer to the moving parts that connect different sections of an excavator arm or boom. They allow the individual segments to pivot and rotate, enabling the complex arm movements needed for digging and material handling. Here are the main types of excavator links and how they work.
Pin Links – The Most Common Type Of Excavator Arm Joint
Pin links are the most common type of excavator arm joint. They use a large metal pin that passes through lugs or ears on the two arm sections. The pin fits into a bushing or bearing to provide a rotating pivot point. Pin links are made from hardened steel for durability and allow the arm segments to rotate 360 degrees. They must be greased regularly to reduce wear on the bushings. If the bushings fail or wear excessively, the pin links can become loose and negatively impact excavator performance.
Bushed Links Feature A Pin Fitted With Bronze Or Polymer
Bushed links feature a pin fitted with bronze, polymer or other wear-resistant bushings. The bushings align and center the pin in the lugs, reducing friction and wear during rotation. They absorb impacts and shock loads that pass through the arm joints during operation. Bushed links provide a smooth pivot motion by minimizing metal-to-metal contact between the pin and lugs. Bushed pin links commonly use thicker pins and quad bushings for heavier-duty applications like large excavators. The bushings themselves should replaced when excessively worn to maintain smooth link movement.
Clevis Links – Connects Two Arm Sections With A Secured Bolt
Clevis links use a clevis-shaped fitting that connects two arm sections with a secured bolt. Unlike pin links, clevis links only allow limited rotation – usually 180 degrees or less. They are designed to handle pushing loads but have less durability compared to pin links. Clevis links are commonly found on excavator dipper sticks or buckets. The bolted fitting helps ensure the arm segments remain securely fastened together during operation. However, regularly tightening and inspecting the bolts is important to maintain proper wear and function.