CAUTION: Install Hand Controls to Prevent Accidental Actuation
Total protection for the two-hand control system from defeat is not possible. However, the user is
required by U.S. and International standards to arrange and protect hand controls to minimize the
possibility of defeat or accidental actuation.
CAUTION: Machine Control Must Provide Anti-Repeat Control
Appropriate anti-repeat control must be provided by the machine control and is required by U.S. and
International standards for single-stroke or single-cycle machines.
This Banner device can be used to assist in accomplishing anti-repeat control, but a risk assessment
must be accomplished to determine the suitability of such use.
Two-Hand Control Safety Distance (Minimum Distance)
The hand controls operator must not be able to reach the hazardous area with a hand or any other body part before the
machine motion ceases. Use the formula below to calculate the safety distance (minimum distance).
WARNING: Location of Touch Button Controls
Hand controls must be mounted a safe distance from moving machine parts, as determined by the
appropriate standard. It must not be possible for the operator or other non-qualified persons to relocate
them. Failure to establish and maintain the required safety distance could result in serious injury or death.
U.S. Applications
The Safety Distance formula, as provided in ANSI B11.19:
Part-Revolution Clutch Machinery
(the machine and its controls allow the machine to stop motion during the hazardous portion of the machine cycle)
Ds = K x (Ts + Tr) + Dpf
For Full-Revolution Clutch Machinery
(the machine and its controls are designed to complete a full machine cycle)
Ds = K x (Tm + Tr + Th)
Ds
the Safety Distance (in inches)
K
the OSHA/ANSI recommended hand-speed constant (in inches per second), in most cases is calculated at 63 in/sec, but may vary between 63
in/sec to 100 in/sec based on the application circumstances;
not a conclusive determination; consider all factors, including the physical ability of the operator, when determining the value of K to be used
Th
the response time of the slowest hand control from the time when a hand disengages that control until the switch opens;
Th is usually insignificant for purely mechanical switches. However, Th should be considered for safety distance calculation when using
electronic or electromechanical (powered) hand controls. For Banner Self-checking Touch Buttons (STBs) the response time is 0.02 seconds
Tm
the maximum time (in seconds) the machine takes to cease all motion after it has been tripped. For full revolution clutch presses with only one
engaging point, Tm is equal to the time necessary for one and one-half revolutions of the crankshaft. For full revolution clutch presses with more
than one engaging point, Tm is be calculated as follows:
Tm = (1/2 + 1/N) x Tcy
N = number of clutch engaging points per revolution
Tcy = time (in seconds) necessary to complete one revolution of the crankshaft
Tr
the response time of the Safety Controller as measured from the time a stop signal from either hand control. The Safety Controller response time
is obtained from the Configuration Summary tab in the Software.
XS/SC26-2 and SC10-2 Safety Controllers
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