ANSI B175.3:2019 pdf free download – Internal Combustion Engine–Powered Hand-Held Grass Trimmers and Brushcutters – Safety and Environmental Requirements
13.3.1. For brushcutters having a dry weight of less than 7.5 kg (1 6.5 lb), at least a single-shoulder harness shall be supplied. A double-shoulder harness shall be provided for all brushcutters exceeding a dry weight of 7.5 kg (1 6.5 lb). The double-shoulder harness shall be designed such that the pressure is evenly distributed on both shoulders of the operator. The design of the double-shoulder harness shall prevent slipping in any direction.
13.3.2. Grass trimmers do not require a harness if dry weight is below 6 kg (1 3.2 lb). For grass trimmers having a dry weight of 6 kg (1 3.2 lb) to 7.5 kg (1 6.5 lb), at least a single-shoulder harness shall be supplied. Grass trimmers with a weight greater than 7.5 kg (1 6.5 lb) shall be supplied with a double-shoulder harness.
13.3.3. All double-shoulder harnesses and restrictive harnesses shall be equipped with a mechanism for quick release either for the connection between unit and harness or between harness and operator. Either the design of the harness or the use of the quick release mechanism shall assure that the unit can be released quickly from the operator in the event of emergency.
13.3.4. Single-shoulder harnesses shall be designed in a way or be equipped with a quick-release mechanism, so that the unit can be released quickly from the operator in the event of emergency.
13.3.5. If a quick-release mechanism is provided it shall release, by a deliberate action, when a vertical load three times the dry weight of the unit is applied to the suspension point while wearing the harness.
13.4. Balance
13.4.1. The requirements in 1 3.4.2 and 1 3.4.3 shall be verified with the fuel tank half filled.
13.4.2. For brushcutters and grass trimmers requiring a harness, with cutting attachments not designed to be partially supported by the ground, the suspension point shall be adjustable so that the unit is freely balanced with the nearest point of the blade 200 mm ± 1 00 mm (8 in ± 4 in) from the ground. For grass trimmers.
13.4.3. For brushcutters and grass trimmers designed to be partially supported by the ground, the suspension point shall be adjustable so that the ground contact force is not greater than 20 N (4.5 lbf). 14. Throttle Control / Throttle Control Latch 14.1. Throttle Control 14.1.1. All units shall be equipped with a throttle control that, when released, automatically reverts to an idling position (unless a throttle control latch to aid in starting is engaged). All blade capable units shall be retained in the idle position by automatic engagement of a throttle control lock-out. When a force is applied to the throttle trigger, while the throttle trigger lock-out is engaged, engine speed shall not increase to a point where the clutch engages and cutting attachment movement begins.
14.1.2. The throttle trigger lock-out function shall be verified by applying a force “F” of 50 N ± 2 N (1 1 .24 lbf ± 0.45 lbf) or the dry weight of the unit, whichever is higher, on the throttle trigger with the throttle trigger lock-out engaged. During the test, the hand-grip shall be fixed, without contacting the throttle trigger lock-out. The specified force shall be applied gradually to the throttle trigger in the direction of travel and held for 5 s ± 1 s. For pivoting triggers, the force shall be applied at the point furthest from the pivot and for linear operating triggers the force shall be applied at the midpoint of the trigger. See Figure 1 1 .