Rule 4123:1-13-02 | Mills.
(A) Mill roll height.
All mills shall be installed so that the top of the operating rolls is no less than fifty inches (one hundred twenty-seven centimeter) above the level on which the operator stands, irrespective of the size of the mill. This distance shall apply to the actual working level, whether it be at the general floor level, in a pit, or on a platform.
(B) Mill controls.
(1) Safety trip control.
A safety trip control shall be provided in front and in back of each mill to stop the mill when it is tripped. It shall be accessible and shall operate readily on contact. The safety trip control shall be one of the following types or a combination thereof.
(a) Pressure-sensitive body bars.
Installed at front and back of each mill twenty inches (50.8 cm) horizontally from the crown face of the roll. These bars shall operate readily by pressure of the mill operator's body. Pressure-sensitive body bars should be installed on new equipment.
(b) Safety trip rod.
Installed in the front and in the back of each mill and located within two inches (5.08 centimeters) of a vertical plane tangent to the front and rear rolls. The trip rods shall be within easy reach of the operator but no more than seventy-two inches (182.88 centimeters) above the level on which the operator stands. The trip rods shall be accessible and shall operate readily whether the rods are pushed or pulled.
(c) Safety trip wire cable or wire center cord.
Installed at the front and back of each mill and located within two inches of a vertical plane tangent to the front and rear rolls. The cables shall be within easy reach of the operator but no more than seventy-two inches (182.88 centimeters) above the level on which the operator stands. The trip wire cable or wire center cord shall operate readily whether cable or cord is pushed or pulled.
(d) Fixed guards.
A fixed bar across the front and one across the back of the mill approximately forty inches (one hundred two centimeters) vertically above the working level and twenty inches (50.8 centimeters) horizontally from the crown face of the roll should be used. A safety trip method as described in paragraph (B)(1) of this rule shall be used with a fixed bar.
(2) Other equipment.
All other equipment, such as a mill divider, support bars, spray pipes, feed conveyors, strip knives, etc., shall be located in such a manner as to avoid interference with access to or operation of safety devices.
(C) Protection by location.
Where a mill is so installed that persons cannot normally reach through, over, under, or around any element to come in contact with the roll bite or be caught between a roll and an adjacent object, then, provided such elements are made a fixed part of a mill, safety control devices listed in paragraph (B) of this rule shall not apply.
(D) Trip and emergency switches.
All trip and emergency switches shall not be of the automatically resetting type, but shall require manual resetting.
(E) Emergency stopping limits.
(1) Determination of distance of travel.
All measurements on mills shall be taken with the rolls running empty at maximum operating speed. Stopping distances shall be expressed in inches of surface travel of the roll from the instant the emergency stopping device is actuated.
(2) When tripped by the emergency stopping device all mills, irrespective of the size of the rolls or their arrangement (individually or group-driven), shall stop within a distance, as measured in inches (centimeters) of surface travel, no greater than one and one-half per cent of the peripheral no-load surface speeds of the respective rolls as determined in feet per minute (centimeter per minute). (See "Figure 1.")
Last updated October 30, 2024 at 2:39 PM
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