1. For a part revolution press, once the cycle is initiated, the press can be st
ID: 457887 • Letter: 1
Question
1. For a part revolution press, once the cycle is initiated, the press can be stopped by signaling the press to disengage the clutch and apply the brake. For a given part revolution press, the total cycle time is 1 second. The time it takes for the die to close once the cycle has been initiated is 0.5 seconds.
a. If the total stop time for a given press equipped with a set of 2-hand controls, as the safeguarding device, is 350 milliseconds, what is the safe distance between the point of operation (hazard zone) and the set of 2-hand controls?
b. What is the safe distance if a 2-hand trip device is used as the safeguarding device in place of the 2 hand-controls?
Explanation / Answer
a. If the total stop time for a given press equipped with a set of 2-hand controls, as the safeguarding device, is 350 milliseconds, what is the safe distance between the point of operation (hazard zone) and the set of 2-hand controls?
The safety distance (Ds) between each two hand control device and the point of operation shall be greater than the distance determined by the following formula:
Ds = 63 inches/second × Ts
where:
Ds = minimum safety distance (inches)
and
Ts = stopping time of the press measured seconds = 350 milliseconds or 0.35 seconds
therefore
Ds = 63 inches/second × Ts
= 63 * 0.35 = 22.05 inches
b. What is the safe distance if a 2-hand trip device is used as the safeguarding device in place of the 2 hand-controls?
The safety distance (Dm) between the two hand trip and the point of operation shall be greater than the distance determined by the following formula:
Dm = 63 inches/second ×Tm;
where:
Dm = minimum safety distance (inches)
and
Tm = the maximum time the press takes for the die closure after it has been tripped (seconds) = 0.5 seconds
Therefore
Dm = 63 inches/second ×Tm = 63 * 0.5 = 31.5 inches
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