3-Pin vs 4-Pin Mechanical Grapples

The difference between the two designs is straightforward and can be clearly identified by their pin configuration.

3-Pin Mechanical Grapple
A 3-pin grapple uses three connection pins. The rotation pin and the bucket pin share the same axis, resulting in a simpler triangular linkage structure.

4-Pin Mechanical Grapple
A 4-pin grapple, as the name suggests, uses four independent pins. This creates a more advanced linkage system with greater structural stability and motion range.

In short, the number of pins directly affects how the grapple opens, moves, and connects to the excavator.

Why RSBM Uses a 4-Pin Design

RSBM mechanical grapples are engineered with a 4-pin configuration for clear performance advantages in real-world applications.

Key Advantages of the 4-Pin Design

1. Compatible with Quick Couplers
4-pin mechanical grapples can be used with quick couplers, allowing faster attachment changes and improved work efficiency.
In contrast, most 3-pin grapples do not support quick coupler connections.

2. Larger Opening, More Flexible Gripping
In a 4-pin design, the grapple stick and excavator arm form a quadrilateral linkage, which enables:

• A wider opening range

• More flexible claw movement

• Better material handling capability

By comparison, a 3-pin grapple forms a triangular structure, which limits opening size and reduces gripping flexibility.

Designed for Practical Performance