BS 1870-5:2002 pdf download – Safety of woodworking machines — Circular sawing machines — Part 5: Circular sawbenches/up-cutting cross-cut sawing machines
5 Safety requirements and/or measures
For guidance in connection with risk reduction by design, see clause 3 of EN 292-2:1991/A1:1995, and in addition :5.1 Controls
5.1.1 Safety and reliability of control systems
For the purposes of this European Standard a safety related control system is one from and including the initialmanual control or position detector to the point of input to the final actuator or element e.g.motor. The safetyrelated control systems of this machine (see EN 954-1:1996) are those for :
starting (see 5.1.3);
normal stopping (see 5.1.4);
interlocking (see 5.2.7.3,5.2.7.4);the braking system (see 5.1.4,5.2.4).
These control systems shall， as a minimum be designed and constructed using “well tried components andprinciples”.
For the purposes of this European Standard “well tried components and principles” means :
a) electrical components if they comply with relevant standards including the following as :
i)EN 60947-5-1:1997, section 3 for control switches with positive opening operation used as mechanicalactuated position detectors for interlocking guards and for relays used in auxiliary circuits;
ii) EN 60947-4-1 for electromechanical contactors and motor-starters used in main circuits;
ii) HD 22.1 S3 for rubber-insulated cables;
iv)HD 21.1 S3 for polyvinyl chloride cable if this cable is additionally protected against mechanicaldamage by positioning (e.g. inside frames).
b) electrical principles if they comply with the first four measures listed in 9.4.2.1 of EN 60204-1:1992.Thecircuits shall be either “hardwired”, or if electronic components are used in safety related control systems “weltried” is fulilled if they are in accordance with 9.4.2.2 (i.e. redundancy with cross-monitoring) or 9.4.2.3(i.e.diversity) of EN 60204-1:1992;
c) mechanical components if, for example，they operate in the positive mode in accordance with thedescription given in 3.5 of EN 292-2:1991/A1:1995;
d)mechanically actuated position detectors for guards if they are actuated in the positive mode and theirarrangementfastening and cam design/mounting comply with the requirements of 5.2 and 5.3 of EN1088:1995.
Time delay devices used in hardwired safety related control circuits can be of category B in accordance with therequirements of EN 954-1:1996 if the time delay device is designed for at least one million actuations.
Verification : By checking the relevant drawings andor circuit diagrams and inspection of the machine, for electricalcomponents by requiring confirmation from the manufacturer of the component which declares conformity with therelevant standards.
5.1.2Position of controls
The start control and the stop control shall be located in the shaded area X of Fiaure 7.
Verification : By checking the relevant drawings, measurement and inspection of the machine.
5.1.3 Starting
See 9.2.5.2 of EN 60204-1:1992 and in addition :
For the purposes of this European Standard “all of the safeguards in place and functional” is achieved by theinterlocking arrangements described in 5.2.7 and “operation” means rotation of the saw spindle.
The exceptions described in 9.2.5.2 of EN 60204-1:1992 are not relevant.
Verification : By checking the relevant drawings andor circuit diagrams, inspection and relevant functional testingof the machine.
5.1.4 Normal stopping
Machines shall be fitted with a stop control which,when actuated shall disconnect power from all the machineactuators and actuate the brake (if provided).
lf the machine is fitted with a mechanical brake this stop control shall be of a category 0 in accordance with therequirements 9.2.2 of EN 60204-1:1992.
lf the machine is fitted with an electrical brake this stop control shall be of category 1 in accordance with therequirements 9.2.2 of EN 60204-1:1992. When initiated the stopping sequence shall be :
a) cut power to machine actuators and actuate the brake;
b) cut power to brake after stopping sequence is complete.
The stopping sequence shall be satisfied at the level of the control circuits. lf a time delay device is used, timedelay shall be at least the maximum run-down time.Either the time delay shall be fixed,or，the time delayadjustment device shall be sealed.
Verification : By checking the relevant drawings andor circuit diagrams, inspection and relevant functional testingof the machine.