UL-60745-2-13:2011 pdf free download – STANDARD FOR SAFETY Hand-Held Motor-Operated Electric Tools – Safety 一Part 2-13: Particular Requirements for Chain Saws.
19.103 Rear hand guard
The hand of the operator shall be protected in case the saw chain breaks or derails. A hand guard shall be provided along the length of the bottom of the rear handle. This guard shall extend from the edge of the handle for at least 30 mm at the guide bar side and at least 100 mm lengthwise (see Figure 104).
Compliance is checked by inspection and measurement.
19.104 Guarding of the moving parts
The drive sprocket and the saw chain behind the spiked bumper shall be guarded to prevent access from both sides and from the top and the rear.
Compliance is checked by means of the straight test probe (see Figure 105). It shall not be possible to touch the drive sprocket and the part of the saw chain behind the spiked bumper with the test probe. There may be openings at the front and below the drive sprocket to allow the ejection of wood chips and to adjust the guide bar and saw chain.
Compliance is checked by inspection.
19.105 Chain catcher
The chain saw shall be fitted with a chain catcher device placed under the saw chain as far to the front as practicable. The chain catcher shall extend sideways at least 5 mm from the centre-plane of the guide bar.
The chain catcher shall have sufficient mechanical strength.
Compliance is checked by inspection and applying Clauses 3 and 4 of ISO 10726. In 4.1 of ISO 10726, a temperature of (-10±3) °C shall apply.
19.106 Spiked bumper
Chain saws shall have a spiked bumper at the front of the machine.
Compliance is checked by inspection.
19.107 Chain brake
If a chain brake operated by a chain brake lever is needed as a part of the anti-kickback system in order to meet the requirements of 19.108, it shall also comply with the requirements of 19.107.1 and 19.107.2.
19107.1 The chain brake shall stop the saw chain with an average braking time not exceeding 0,12 s and a maximum braking time not exceeding 0,15 s.
Compliance is checked by the following test.
The chain saw and chain tension shall be adjusted as for normal use, following the manufacturer’s instruction. The chain tension shall generally be adjusted so that, when a 1 kg mass is hanging from the centre of the cutting length along the lower portion of the chain, the gap between the chain side link and the guide bar is a minimum of 0,017 mm per millimetre of guide bar length.
With the saw chain lubricated as in normal use and operated at rated voltage, the brake actuator is set in motion by the impact of a pendulum. This pendulum shall have a mass of 0,70 kg, a hammer with a flat strike face of 50 mm diameter and an arm of 700 mm length. The release height of the pendulum shall be 200 mm. The time for the saw chain to stop shall be measured from the moment of impact with the actuator (see Figure 106).
The chain brake shall be operated a total of 25 times. The maximum stopping time and the average stopping time of the saw chain shall be measured at the first five and the last five braking operations.