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Machine Guarding
Presses

Two-Hand Controls can be used as safeguarding devices in the single stoke mode of operation on part revolution clutch presses. Similar to the two-hand trip, this device keeps the operators hands away from the point of operation during the entire machine stroke.

Two-Hand Control Regulations
Press Operation Using Two-hand Controls
Press operation using two-hand controls
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Single Stroke Requirements
  • Each hand control must be protected against unintended operation and arranged by design, construction, and/or separation so that the concurrent use of both hands is required to trip the press. [29 CFR 1910.217(b)(7)(v)(a)]

  • The control system must be designed to permit an adjustment which requires concurrent pressure from both hands during the die closing portion of the stroke. [29 CFR 1910.217(b)(7)(v)(b)]

  • The control system must incorporate an anti-repeat feature. [29 CFR 1910.217(b)(7)(v)(c)]
Dual Two-Hand Control Operation
Dual two-hand control operation. Press operation requires separate sets of two-hand controls for two operators.
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  • The control systems must be designed to require the release of all hand controls before an interrupted stroke can be resumed. This requirement pertains only to those single stroke, two-hand controls manufactured and installed on or after August 31, 1971. [29 CFR 1910.217(b)(7)(v)(d)]

Please also see the formula used to compute the minimum safety distance on mechanical power presses to meet the ANSI B11.1 Press Safety Standard or information on stop-time measuring units.



How Does It Work?

Two-hand control, as a point of operation safeguarding device for press brakes, is ideal for short-run job-shop operations. Piece parts can vary from quite small to very large.

STEP 1

By depressing the control buttons, the operator initiates the press brake stroke.

STEP 2

The operator must hold the buttons until the slide completes its downward travel. If the operator removes a hand from one of the controls, the slide will stop. In the single stroke or Hi/Lo mode, the slide will make one complete stroke.

Example of Two-Hand Control Operation
Example of two-hand control operation
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STEP 3

In the sequence mode, the slide will automatically stop at a preset position 1/4" or less above the work piece. This position is adjustable for different feed-line heights or material thickness.

STEP 4

If the work piece is not already placed in the die, it may be inserted at this time.

STEP 5

The two-hand control or the foot switch is now re-initiated, causing the slide to continue through the bottom of the stroke and finishing at top dead center (TDC).


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