Overview
ISO 6533:2020 - Forestry machinery: Portable chain‑saw front hand‑guard - Dimensions and clearances specifies dimensional and clearance requirements for the front hand‑guard on portable hand‑held chain‑saws. The standard ensures the guard functions both as a physical shield between the operator’s hand and the saw‑chain and as an actuator for manually operated chain brakes. It defines how measurements are taken (including reference point X and required test forces) and excludes certain wrap‑around handle regions as noted in the scope.
Key topics and technical requirements
- Scope and purpose: Dimensions and clearances for front hand‑guards and their openings to ensure operator safety and reliable chain‑brake actuation.
- Reference point X: Determined using a type A gauge (see gauge sizes) aligned under the front‑handle centreline; procedures are given when direct contact is not possible.
- Gauge probes and forces: Measurements use rigid gauges (Types A, B, C) and test probes per IEC 61032; test force for clearance and play checks is 10 N (including gravity component).
- Width requirement (W): Guard height requirements shall be met across a width W of at least 100 mm measured from X (±3 mm) to the left.
- Height requirements (H and H1A):
- Basic height H above the top contour of the front handle: ≥ 20 mm.
- If guard also activates chain brake: H (disengaged) ≥ 20 mm with 10 N pre‑load; H1A (engaged) ≥ 0 mm without pre‑load.
- Chain access and safety radius: If the saw‑chain is unprotected within 120 mm of X, the design must prevent direct access; direct access ≤ 120 mm must resist a Type B IEC probe under 10 N.
- Openings and clearances:
- Front hand‑guard openings must prevent a Type C gauge (56 × 82 mm) from passing through in any direction.
- Clearance between guard and saw body must likewise prevent Type C passage when held at X.
- Clearance between guard and front handle must allow Type A (35 × 100 mm) to pass but prevent Type B (70 × 100 mm) from passing or moving below the handle centreline.
Gauge dimensions (as specified)
- Type A: D 35 mm, Length 100 mm, Corner radius 5 mm
- Type B: D 70 mm, Length 100 mm, Corner radius 0.5 mm
- Type C: D 56 mm, Length 82 mm, Corner radius 0.5 mm
Applications and users
ISO 6533:2020 is primarily used by:
- Chain‑saw designers and manufacturers (product design and compliance)
- Test laboratories and conformity assessment bodies (safety verification)
- Certification and regulatory agencies (type approval and market surveillance)
- Safety engineers and procurement specialists (equipment selection and risk reduction)
- Training organizations (safe equipment understanding)
Related standards
- ISO 6531 - Portable chain‑saws: Vocabulary (terms and definitions)
- IEC 61032 - Probes for verification (used for contact/access testing)
Keywords: ISO 6533:2020, front hand‑guard, portable chain‑saw, dimensions, clearances, chain brake, safety, gauges A B C, reference point X, IEC 61032.
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