Machine Guarding Definitions

From the Code of Federal Regulations (CFR) § 1910.211

  • Adjustable barrier guard means a barrier requiring adjustment for each job or die setup.
  • Antirepeat means the part of the clutch/brake control system designed to limit the press to a single stroke if the tripping means is held operated. Antirepeat requires release of all tripping mechanisms before another stroke can be initiated. Antirepeat is also called single stroke reset or reset circuit.
  • Bolster plate means the plate attached to the top of the bed of the press having drilled holes or T-slots for attaching the lower die or die shoe.
  • Brake means the mechanism used on a mechanical power press to stop and/or hold the crankshaft, either directly or through a gear train, when the clutch is disengaged.
  • Brake monitor means a sensor designed, constructed, and arranged to monitor the effectiveness of the press braking system.
  • Clutch means the coupling mechanism used on a mechanical power press to couple the flywheel to the crankshaft, either directly or through a gear train.
  • Concurrent means acting in conjunction, and is used to describe a situation wherein two or more controls exist in an operated condition at the same time.
  • Continuous means uninterrupted multiple strokes of the slide without intervening stops (or other clutch control action) at the end of individual strokes.
  • Device means a press control or attachment that:
    • (i) Restrains the operator from inadvertently reaching into the point of operation, or
    • (ii) Prevents normal press operation if the operator’s hands are inadvertently within the point of operation, or
    • (iii) Automatically withdraws the operator’s hands if the operator’s hands are inadvertently within the point of operation as the dies close, or
    • (iv) Prevents the initiation of a stroke, or stops of stroke in progress, when there is an intrusion through the sensing field by any part of the operator’s body or by any other object.
  • Die means the tooling used in a press for cutting or forming material. An upper and a lower die make a complete set.
  • Feeding means the process of placing or removing material within or from the point of operation.
  • Fixed barrier guard means a die space barrier attached to the press frame.
  • Foot control means the foot operated control mechanism designed to be used with a clutch or clutch/brake control system.
  • Foot pedal means the foot operated lever designed to operate the mechanical linkage that trips a full revolution clutch.
  • Full revolution clutch means a type of clutch that, when tripped, cannot be disengaged until the crankshaft has completed a full revolution and the press slide a full stroke.
  • Gate or movable barrier device means a movable barrier arranged to enclose the point of operation before the press stroke can be started.
  • Guard means a barrier that prevents entry of the operator’s hands or fingers into the point of operation.
  • Hand feeding tool means any hand held tool designed for placing or removing material or parts to be processed within or from the point of operation.
  • Holdout or restraint device means a mechanism, including attachments for operator’s hands, that when anchored and adjusted prevent the operator’s hands from entering the point of operation.
  • Inch means an intermittent motion imparted to the slide (on machines using part revolution clutches) by momentary operation of the Inch operating means. Operation of the Inch operating means engages the driving clutch so that a small portion of one stroke or indefinite stroking can occur, depending upon the length of time the Inch operating means is held operated. Inch is a function used by the die setter for setup of dies and tooling, but is not intended for use during production operations by the operator.
  • Interlocked press barrier guard means a barrier attached to the press frame and interlocked so that the press stroke cannot be started normally unless the guard itself, or its hinged or movable sections, enclose the point of operation.
  • Jog means an intermittent motion imparted to the slide by momentary operation of the drive motor, after the clutch is engaged with the flywheel at rest.
  • Manual feeding means feeding wherein the material or part being processed is handled by the operator on each stroke of the press.
  • Operator’s station means the complete complement of controls used by or available to an operator on a given operation for stroking the press.
  • Part revolution clutch means a type of clutch that can be disengaged at any point before the crankshaft has completed a full revolution and the press slide a full stroke.
  • Pinch point means any point other than the point of operation at which it is possible for a part of the body to be caught between the moving parts of a press or auxiliary equipment, or between moving and stationary parts of a press or auxiliary equipment or between the material and moving part or parts of the press or auxiliary equipment.
  • Point of operation (from § 1910.217 Mechanical Power Presses) means the area of the press where material is actually positioned and work is being performed during any process such as shearing, punching, forming, or assembling.
  • Point of operation (from § 1910.219 Mechanical Power-Transmission Apparatus) means that point at which cutting, shaping, or forming is accomplished upon the stock and shall include such other points as may offer a hazard to the operator in inserting or manipulating the stock in the operation of the machine.
  • Presence sensing device means a device designed, constructed and arranged to create a sensing field or area that signals the clutch/brake control to deactivate the clutch and activate the brake of the press when any part of the operator’s body or a hand tool is within such field or area.
  • Press means a mechanically powered machine that shears, punches, forms or assembles metal or other material by means of cutting, shaping, or combination dies attached to slides. A press consists of a stationary bed or anvil, and a slide (or slides) having a controlled reciprocating motion toward and away from the bed surface, the slide being guided in a definite path by the frame of the press.
  • Pull-out device means a mechanism attached to the operator’s hands and connected to the upper die or slide of the press, that is designed, when properly adjusted, to withdraw the operator’s hands as the dies close, if the operator’s hands are inadvertently within the point of operation.
  • Repeat means an unintended or unexpected successive stroke of the press resulting from a malfunction.
  • Safety block means a prop that, when inserted between the upper and lower dies or between the bolster plate and the face of the slide, prevents the slide from falling of its own deadweight.
  • Safety system means the integrated total system, including the pertinent elements of the press, the controls, the safeguarding and any required supplemental safeguarding, and their interfaces with the operator, and the environment, designed, constructed and arranged to operate together as a unit, such that a single failure or single operating error will not cause injury to personnel due to point of operation hazards.
  • Single stroke means one complete stroke of the slide, usually initiated from a full open (or up) position, followed by closing (or down), and then a return to the full open position.
  • Slide means the main reciprocating press member. A slide is also called a ram, plunger, or platen.
  • Stop control means an operator control designed to immediately deactivate the clutch control and activate the brake to stop slide motion.
  • Trip or (tripping) means activation of the clutch to “run” the press.
  • Turnover bar means a bar used in die setting to manually turn the crankshaft of the press.
  • Two-hand trip means a clutch actuating means requiring the concurrent use of both hands of the operator to trip the press.
  • Two hand control device means a two hand trip that further requires concurrent pressure from both hands of the operator during a substantial part of the die-closing portion of the stroke of the press.