Two-hand control separation (safety) distance – Banner DUO-TOUCH Run Bar with STB Buttons User Manual

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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 may result in

serious injury or death.

Two-Hand Control Separation (Safety) Distance

Both hand controls must be located far enough away from the nearest hazard point that the operator cannot reach the

hazard with a hand or other body part before the hazardous motion ceases. This is the “separation distance” (“safety

distance”), and may be calculated as follows. The formulas differ slightly between U.S. and EU-Certified installations, but

the concepts are similar.

Formulas for U.S. Installations

For Part-Revolution Clutch Machinery where the machine and

its controls allow the machine to stop motion during the hazardous

portion of the machine cycle, use the following formula:

D

s

= K x (T

s

+ T

r

+ T

h

)

For Full-Revolution Clutch Machinery where the machine and

its controls are designed to complete a full machine cycle, once

activated, use the following formula:

D

s

= K × (T

m

+ T

r

+ T

h

)

Formula for EU-Certified Installations

The formula used to calculate the minimum

safety distance (S) from the nearest actuator

to the danger zone is:

S = (K × T) + C

In all cases, where:

D

s

= the separation (safety) distance in inches

S = the minimum safety distance in millimeters
K = OSHA/ANSI and ISO 13855 hand speed constant of 1600mm/s (63" per second) (NOTE 1 below)
T = the overall stop time of the machine, measured from the actuation of the sensing function to the final ceasing of all

motion.
T

s

= the stop time (in seconds) of the machine, measured from the application of the “stop” signal to the final ceasing

of all motion, including stop times of all relevant control elements, and measured at maximum machine velocity (see

NOTE 2)
T

r

= 0.035 seconds (the response time of the Module as measured from the time either hand disengages a hand

control.
T

h

= the response time of the slowest hand control (from the time when a hand disengages that control until the switch

opens; see NOTE 3)

T

m

= 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, T

m

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, T

m

is calculated as follows:

T

m

= (1/2 + 1/N) × T

cy

where:

N = number of clutch engaging points per revolution
T

cy

= time (in seconds) necessary to complete one revolution of the crankshaft

C = the added distance due to depth penetration factor: 250 mm, per ISO 13855. The ISO 13855 “C” factor can be

reduced to 0 if the risk of encroachment is eliminated, but the safety distance must always be 100 mm or greater.

NOTES:

1. The hand-speed constant (K) has been determined by various studies, and although these studies indicate speeds

of 1600 mm/s (63”/second), 2000 mm/s (79”/second), to more than 2540 mm/s (100”/second), they are not

conclusive determinations. The employer should consider all factors, including the physical ability of the operator,

when determining the value of K to be used.

2. T

s

is usually measured by a stop-time measuring device. If the specified machine stop time is used, add at least

20% as a safety factor to account for brake system deterioration. If the stop-time of the two redundant machine

control elements is unequal, the slower of the two times must be used for calculating the separation distance.

3. T

h

is usually insignificant for purely mechanical switches. However, Th should be considered for safety distance

calculation when using electronic or electromechanical (i.e. powered) hand controls. For Banner Self-checking

Touch Buttons (STBs), response time = 0.02 seconds.

DUO-TOUCH Run Bar with STB Buttons

Datasheet 131634_web Rev.

E

www.bannerengineering.com - tel: 763-544-3164

5

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