October 7 Flashcards
for woodworking machinery, emphasis is placed…
upon the importance of maintaining cleanliness around woodworking machinery, particularly as regards the effective functioning of guard and the prevention of fire hazards in switch enclosures, bearings, and motors.
True or False: Push sticks or push blocks shall be provided at the workplace in the several sizes and type suitable for the work to be done
True
Abrasive Wheel Machinery: Work Rests
On offhand grinding machines, work rests shall be used to support the work. They shall be of rigid construction and designed to be adjustable to compensate for wheel wear. Work rests shall be kept adjusted closely to the wheel with a maximum opening of one-eighth inch to prevent the work from being jammed between the wheel and the rest, which may cause wheel breakage. The work rest shall be securely clamped after each adjustment. The adjustment shall not be made with the wheel in motion
Abrasive Wheel Machinery: Exposure Adjustment
Safety guards, where the operator stands in front of the opening, shall be constructed so that the peripheral protecting member can be adjusted to the constantly decreasing diameter of the wheel. The maximum angular exposure above the horizontal plane of the wheel spindle as specified in this section shall never be exceeded, and the distance between the wheel periphery and the adjustable tongue or the end of the peripheral member at the top shall never exceed one-fourth inch.
Inspection of Abrasive Wheel machinery
Immediately before mounting, all wheels shall be closely inspected and sounded by the user (ring test) to make sure they have not been damaged in transit, storage, or otherwise. The spindle speed of the machine shall be checked before mounting of the wheel to be certain that it does not exceed the maximum operating speed marked on the wheel. Wheels should be tapped gently with a light nonmetallic implement, such as the handle of a screwdriver for light wheels, or a wooden mallet for heavier wheels. If they sound cracked (dead), they shall not be used. This is known as the “Ring Test”
“Bite”
the nip point between any two inrunning rolls
“Calender”
a machine equipped with two or more metal rolls revolving in opposite directions and used for continuously sheeting or plying up robber and plastic compounds and for fractioning or coating materials with rubber and plastic compounds - VERTICAL
“Mill”
a machine consisting of two adjacent metal rolls, set horizontally, which revolve in opposite directions used for the mechanical working of rubber and plastics compounds
Mills Safety Controls - safety trip control
A safety trip control shall be provided in front and in back of each mill. 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:
- pressure-sensitive body bar
- safety tripod
- safety tripwire cable or wire center cord
Calender Safety Controls - Safety trip, Face
A safety tripod, cable, or wire center cord shall be provided across each pair of in-running rolls extending the length of the face of the rolls. It shall be readily accessible and operate whether pushed or pulled. The safety tripping devices shall be located within reach of the operator and the bite.
Calender Safety Controls - Safety Trip, Side
On both sides of the calender and near each end of the face of the roll, there shall be a cable or wire center cord connected to the safety trip. They shall operate readily when pushed or pulled
Stopping Limits for calenders and mills - determination of distance of travel
All measurements on mills and calenders 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
stopping limits for mills
not greater than 1 1/2 percent of the peripheral no-load surface speeds of respective rolls
stopping limits for calenders
not greater than 1 ¾ percent of the peripheral no-load surface speeds of the respective calender rolls.
“Press”
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
“Device” for a mechanical power press
a press control or attachment that:
- restrains the operator from inadvertently reaching into point of operation
- prevents normal operation if the operators hand are inadvertently within point of operation
- Automatically withdraws the operators hands if the operators hands are inadvertently within the point of operation as the dies close, or
- Prevents the initiation of a stroke, or stops a stroke in progress, when there is an intrusion through the sensing field by any part of the operators body or by any other object
Devices for mechanical power presses include:
- presence sensing devices
- holdout or restraint devices
- pull-out devices
- two hand control devices
- interlocked press barrier guards
Two-hand trips for mechanical power presses
a two-hand trip shall have the individual operators hand controls protected against unintentional operation and have the individual operators hand controls arranged by design and construction and/or separation to require the use of both hands to trip the press and use a control arrangement requiring concurrent operation of the individual operators hand controls
Break system monitoring for mechanical power presses
When required by this section, the brake monitor shall be so constructed as to automatically prevent the activation of a successive stroke if the stopping time or braking distance deteriorates to a point where the safety distance being utilized does not meet the requirements
Point of operation devices (in mechanical power presses) shall protect the operator if the operators hands are inadvertently places in the point of operation by:
- preventing and/or stopping normal stroking of press
- Preventing the operator from inadvertently reaching into the point of operation, or withdrawing his hands
- Preventing the operator from inadvertently reaching into the point of operation at all times
- Requiring application of both of the operators hands to machine operating controls and locating such controls at the “safety” distance from the point of operation
- Enclosing the point of operation before a press stroke can be initiated and maintaining this closed condition until motion has ceased.
Inspection and maintenance of mechanical power presses
- it shall be the responsibility of the employer to establish and follow a program of periodic and regular inspections of his power presses to ensure that all their parts, auxiliary equipment, and safeguards are in a safe operating condition and adjustment. The employer shall maintain a certification record of inspection
- each press shall be inspected and tested no less than weekly to determine the condition of the clutch/brake mechanism, antirepeat feature and single stroke mechanism. Necessary maintenance or repair or both shall be performed and completed before the press is operated.
Reports of injuries to employees operating mechanical power presses
the employer SHALL, within 30 days of the occurrence, report to either OSHA or the State agency administering a plan all point of operation injuries to operators or other employees
Presence Sensing Device Initiation (PSDI) for mechanical power presses
- presence sensing devices can be used for both guarding and initiation of machine action
- Presence sensing device must meet strict guidelines
Prime-mover guards: Flywheels
- flywheels located so that any part is 7 feet or less above floor or platform shall be guarded
- wherever flywheels are above working areas, guards shall be installed having sufficient strength to hold the weight of the flywheel in the event of a shaft or wheel mounting failure
