INDUSTRY COMPONENT

Arm

The arm is the primary structural component of a wheeled excavator that connects the boom to the bucket, enabling digging, lifting, and material handling operations.

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Component Specifications

Definition
The arm, also known as the dipper or stick, is a critical articulated component in wheeled excavators that transmits hydraulic force from the boom to the bucket. It functions as a lever system that determines the machine's digging depth, reach, and lifting capacity through precise angular movements controlled by hydraulic cylinders. This component must withstand significant bending moments, torsional stresses, and cyclic loading during excavation operations while maintaining structural integrity and dimensional stability.
Working Principle
The arm operates on lever mechanics and hydraulic actuation principles. Hydraulic cylinders attached to the boom and arm create controlled extension/retraction movements, converting hydraulic pressure into mechanical force. The arm's pivot points at the boom connection and bucket linkage create a compound lever system that amplifies force at the bucket while maintaining precise positional control through the operator's hydraulic valve inputs.
Materials
High-strength low-alloy steel (HSLA) grades such as ASTM A572 or equivalent, with yield strength ≥345 MPa. Typically manufactured through precision cutting, welding, and heat treatment processes to achieve optimal strength-to-weight ratio and fatigue resistance.
Technical Parameters
  • Length_range 2.5-6.0 meters
  • Pin_diameter 80-150 mm
  • Wall_thickness 15-40 mm
  • Weight_capacity 5-25 tons
  • Operating_pressure 280-350 bar
Standards
ISO 13031, ISO 9244, DIN 15018, DIN EN 13001

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Arm.

excavator arm dipper stick hydraulic arm construction equipment components heavy machinery parts digging arm specifications excavator attachments Arm Arm in Machinery and Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Wheeled Excavator

A mobile construction machine with rubber tires for excavation, loading, and material handling operations.

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Excavators

Heavy construction equipment used for digging, trenching, demolition, and material handling operations.

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Engineering Analysis

Risks & Mitigation
  • Structural fatigue cracking
  • Hydraulic cylinder seal failure
  • Pin and bushing wear
  • Overload deformation
  • Corrosion in joints
FMEA Triads
Trigger: Cyclic loading exceeding material fatigue limits
Failure: Crack propagation in weld zones or stress concentration areas
Mitigation: Implement regular non-destructive testing (NDT), use stress-relieved welding procedures, and maintain within rated load limits
Trigger: Inadequate lubrication at pivot points
Failure: Accelerated wear of pins and bushings leading to slop and reduced precision
Mitigation: Establish preventive maintenance schedule with proper greasing, use wear-resistant bushing materials, and monitor clearance regularly

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
±2 mm on pin bore diameters, ±1° on angular alignment, surface finish Ra ≤ 6.3 μm on bearing surfaces
Test Method
Ultrasonic testing for material integrity, load testing to 150% of rated capacity, finite element analysis (FEA) validation

Procurement Evaluation Criteria

Not customer reviews or live demand data. These dimensions support RFQ preparation and supplier evaluation.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What is the difference between a wheeled excavator arm and a tracked excavator arm?

Wheeled excavator arms are typically lighter and designed for faster cycle times with slightly reduced digging forces compared to tracked versions, optimized for mobility and versatility on hard surfaces.

How often should excavator arm pins and bushings be inspected?

Arm connection points should be inspected every 250 operating hours for wear, with lubrication applied daily. Complete pin and bushing replacement is typically required every 2,000-3,000 hours depending on operating conditions.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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Arch Plate Arm (Stick)