Two-Hand Trip Devices
The two-hand trip devices require the placement of hands on both control buttons at the same time to activate the machine cycle, after which the hands are free.
This device is usually used with machines equipped with full-revolution clutches.
The trips must be placed far enough from the point of operation to make it impossible for the operator to move his or her hands from the trip buttons or handles into the point of operation before the first half of the cycle is completed. The distance from the trip button depends upon the speed of the cycle and the band speed constant. Thus the operator's hands are kept far enough away to prevent them from being placed in the danger area prior to the slide/ram or blade reaching the full "down" position. To be effective, both two-hand controls and trips must be located so that the operator cannot use two hands or one hand and another part of his/her body to trip the machine.
| Safeguarding Action | Advantages | Limitations |
|
Concurrent use of two hands on separate controls prevents hands from being in the danger area when machine cycle starts |
Operator's hands are away from danger area Can be adapted to multiple operations No obstruction to hand feeding Does not require adjustment for each operation |
Operator may try to reach into danger area after tripping machine Some trips can be rendered unsafe by holding with arm or blocking, thereby permitting one-hand operation Protects only the operator May require special fixtures |
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3-6. Which device requires the placement of hands on both control buttons at the same time to activate the machine cycle, after which the hands are free?
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