Arm: Weight_capacity 5-25 tons, Length_range 2.5-6.0 meters

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

Parameter	Typical range	Notes & selection driver
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

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 13031, ISO 9244, DIN 15018, DIN EN 13001

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

Typical Suppliers & Equivalents

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

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Arm

Manufacturer profiles associated with Arm.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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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.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

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.

Arm