Machine Guarding eTool
Presses » Two-Hand Controls
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.
Press operations requiring more than one operator must provide each operator with separate two hand controls where each set must be engaged to complete a machine stroke. The removal of a hand from any control button will stop the slide. [29 CFR 1910.217(c)(3)(vii)(a)]
Two-hand controls' position must be fixed so that only a supervisor or safety engineer is capable of relocating them. [29 CFR 1910.217(c)(3)(vii)(d)]
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)]
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)]
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.
By depressing the control buttons, the operator initiates the press brake stroke.
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.
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.
If the work piece is not already placed in the die, it may be inserted at this time.
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).