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4
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Precautions
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Caution on Design
Warning
①
There is a possibility of dangerous sudden action by air cylinders if sliding parts of machinery
are twisted due to external forces, etc.
In such cases, human injury may occur; e.g., by catching hands or feet in the machinery, or damage to the
machinery itself may occur. Therefore, the machine should be adjusted to operate smoothly and designed to
avoid such dangers.
②
A protective cover is recommended to minimize the risk of personal injury.
If a stationary object and moving parts of a cylinder are in close proximity, personal injury may occur. Design
the structure to avoid contact with the human body.
③
Securely tighten all stationary parts and connected parts so that they will not become loose.
Especially when a cylinder operates with high frequency or is installed where there is a lot of vibration, ensure
that all parts remain secure.
④
A deceleration circuit or shock absorber may be required.
When a driven object is operated at high speed or the load is heavy, a cylinder’s cushion will not be sufficient
to absorb the impact. Install a deceleration circuit to reduce the speed before cushioning, or install an external
shock absorber to relieve the impact.
In this case, the rigidity of the machinery should also be examined.
⑤
Consider a possible drop in circuit pressure due to a power outage, etc.
When a cylinder is used in a clamping mechanism, there is a danger of workpieces dropping if there is a
decrease in clamping force due to a drop in circuit pressure caused by a power outage, etc. Therefore, safety
equipment should be installed to prevent damage to machinery and human injury. Suspension mechanisms and
lifting devices also require consideration for drop prevention.
⑥
Consider a possible loss of power source.
Measures should be taken to protect against bodily injury and equipment damage in the event that there is a
loss of power to equipment conrtolled by pneumatics, electricity, or hydraulics.
⑦
Design circuitry to prevent sudden lurching of driven objects.
When a cylinder is driven by an exhaust centre type directional control valve or when starting up after residual
pressure is exhausted from the circuit, etc., the piston and its driven object will lurch at high speed if pressure
is applied to one side of the cylinder because of the absence of air pressure inside the cylinder. Therefore,
equipment should be selected and circuits designed to prevent sudden lurching, because there is a danger of
human injury and/or damage to equipment when this occurs.
⑧
Consider emergency stops.
Design so that human injury and/or damage to machinery and euqipment will not be caused when machinery is
stopped by a safety device under abnormal conditions, a power outage or a manual emergency stop.
⑨
Consider the action when operation is restarted after an emergency stop or abnormal stop.
Design the machinery so that human injury or equipment damage will not occur upon restart of operation.
When the cylinder has to be reset at the starting position, install manual safety equipment.
