safeguarding is:
Any means of preventing or controlling personnel from coming in contact with the moving parts of machinery or equipment that would potentially cause physical harm.
Device is:
A mechanism or control designed for safeguarding at the point of operation. Devices include presence-sensing devices, movable-barrier devices, holdout or restraint devices, pull-back (out) devices, two-hand-trip devices, and two-hand-control devices.
Guard is:
A barrier designed for hazard control at the point of operation. Guards include die-enclosure guards, fixed-barrier guards, interlocked-barrier guards, and adjustable-barrier guards.
Enclosure is:
Safeguarding by fixed physical barriers mounted on or around a machine to prevent access to the moving parts.
Location is:
Safeguarding by location results when a hazard is physically inaccessible under normal operating conditions or permitted only if the other precautionary restrictions can be met.
Point of Operation is:
The area on a machine where material is positioned for processing or where work is actually being performed on the material.
Power Transmission:
includes all mechanical parts - such as gears, cams, shafts, pulley, belts clutches, brakes, and rods - that transmit energy and motion from a source of power to equipment or a machine.
Mechanical hazards occur in:
The Point of Operation, Power Transmission Apparatus, Other Moving Parts
what are the five classifications that safeguards are grouped under:
Guards, Devices, Locations/Distance, Feeding and ejection methods, and Miscellaneous aids
Guards are:
barriers which prevent access to danger areas, there are four general types
the four general types of guards are:
Fixed guards, Interlocked guards, Adjustable guards, Self-Adjusting guards
Fixed guards are:
a permanent part of the machine and not dependent upon moving parts to perform its intended function. Provides a barrier and is preferable to all other types of guards. It shall prevent entry of hands or fingers into the point of operation by reaching through, over, under or around the guard
Interlocked guards are:
designed to automatically shut off or disengage the machine if the guard is opened or removed
Interlocked guards may use:
Electrical power, Mechanical power, Hydraulic power, Pneumatic power, or any combination of power sources
Interlocked guards should not:
prevent "inching" by remote control if required
Replacing guards should not:
automatically restart the machine
Adjustable guards:
Provides a barrier which may be adjusted to facilitate a variety of production operations. Accommodate various sizes of stock
Adjustable guards are typically used on:
Bandsaws, Tablesaws, Power presses, Routers, Similar equipment
Self-Adjusting guards are typically used on:
Jointers, Radial arm saws,Tablesaws, Circular saws, Routers
Self-Adjusting guards advantages:
Off-the-shelf guards are often commercially available
Machine guard devices fall into four general types:
Presence-Sensing devicesPullback devicesRestraint devicesSafety trip controlsTwo hand controls/tripsType A or B Gates
Devices may perform one of several function:
Stop a machine if a body part is in dangerRestrain or withdraw a hand if it is in dangerRequire activation by the use of both handsProvide a barrier synchronized to the operation
Types of Presence-Sensing in devices:
PhotoelectricRadiofrequencyElectromechanical
Pullback Devices:
Utilizes a series of cables attached to the operator's hands, wrists, and/or arms.Primarily used on machines with stroking action. Allows access to the point of operation when the slide/ram is up.
Two hand controls requires:
constant, concurrent pressure for substantial portion of down stroke to activate the machine
two hand controls:
The operator's hands are required to be at a safe location (on control buttons) and at a safe distance from the danger area while the machine completes its closing cycle
A gate is a:
Movable barrier device which protects the operator at the point of operation before the machine cycle can be started
FEEDING AND EJECTING MECHANISMS is:
Any mechanism that eliminates handling of work should reduce exposure to those hazards, especially in operations that place the operator's hands in a danger zone.
Feeding Mechanisms are:
Rolls, Indexed by Machine, Chutes, Movable Dies, Dial Feed, Plungers, or Sliding Bolsters
Ejection Methods are:
positive stripper plates, spring pressure pads, mechanical lift dogs, compressed air jets or pneumatic or hydraulic lift pins.
Robotics:
Perform Work Usually Performed by Operator, including feeding and ejection.
Hand feeding tools are:
not a point of operation guard or protection device and shall not be used in lieu of the "guards" or devices required in this section
Exposure to Fan Blades:
When the periphery of the blades of a fan is less than seven (7) feet above the floor or working level, the blades shall be guarded. The guard shall have openings no larger than one-half (1/2) inch
Anchoring Fixed Machinery are:
Machines designed for a fixed location shall be securely anchored to prevent walking or moving
Types of woodworking machinary:
Table Saws, Band Saws, Scroll Saws, Lathes, Jointers, Shapers, Planers/Molders, Drill Presses, Belt Sanders, Tenoning Machine
General Requirements for Woodworking Machinery:
The frames and all exposed, noncurrent-carrying metal parts of portable electric woodworking machinery operated at more than 90 volts to ground shall be grounded.
Saws are:
Used primarily in woodworking and manufacturing shops for cutting materials
Types of saws:
Table, Radial, Band, Mitre/Chop, Circular, Sabre, Concrete
Table saw:
A machine with a circular saw blade which is mounted under a table and only a portion of the blade extends above the table top.
operator controls on table saws:
Use a push stick for small pieces of wood. [1910.213(s)(9)]
Rabbeting and Dadoing:
Impossible to use a spreader and often impractical to use the standard hood guard.Must use a push stick
Radial arm saws:
The operator cuts the wood stock by pulling the saw towards them
Band Saws:
consisted of a continuous band of metal with teeth that rides on two wheels.
guard the blade of a band saw entirely except at:
the point of operation [1910.213(i)(1)].
Use an adjustable guard for the portion of the blade between the:
upper wheel guard and the table [1910.213(i)(1)].
Mitre Saws are:
used to make accurate crosscuts and miters in a workpiece
Lathes are:
used for shaping round parts, such as table legs. Two types of lathes are used in the woodworking industry: manually operated or CNC operated.
A drill press is:
a wood cutting machine that uses a multiple-cutting-edged rotating tool to remove wood and produce a hole in the stock.
Milling Machines:
is the machining process of bringing metal into contact with a rotating multi-edged cutter. The stock is clamped to the work table. As the table moves, the metal stock comes into contact with the cutting head.
Planers are:
are woodworking machines used to dress and size rough-sawed lumber on one or more sides - planing boards to an even thickness.
Jointers:
face or flatten wood and are used primarily to joint small pieces of material. The operator passes stock over a cylindrical, multiple-knife cutter head, while keeping the stock flush against a guide.
Belt sanders:
finish stock by using a coated abrasive surface to remove material.
A grinding machine is a:
metal working machine which uses an abrasive wheel against the metal surface causing a change in the surface or shape of the metal.
Types of grinders:
pedestal, bench, and surface
Work Rest (Tool Rest):
On off hand grinding, work rests are required, to support the workRigid construction, and adjustable with wheel wearMust be kept closely adjusted, max gap = 1/8" to prevent work from jamming & breaking wheel
Tongue Guard:
Located at the top of the wheel housing.Prevent sparks and material from coming back around the wheel and out from the top.The distance between the periphery and the adjustable tongue guard shall never exceed one-fourth inch
Ring test for mounting of wheels:
Sound the wheel by tapping around the wheel periphery with a wood handled screwdriver.Good wheel portions will "ring" like a bellCracks will sound "dead
Mechanical power press:
a mechanically or hydraulically powered machine that shears, punches, forms or assembles metal or other material by means of cutting, shaping, or combination dies attached to slides.
Antirepeat:
the part of the clutch/brake control system designed to limit the press to a single stroke if the actuating means is held or stuck on "operate.
Bolster Plate:
the plate attached to the top of the bed of the press component; it has drilled holes or T-slots for attaching the lower die or die shoes.
Brake:
the mechanism used on a mechanical power press component to stop and/or hold the slides, either directly or through a gear train, when the clutch is disengaged.
Brake Monitor:
a sensor that has been designed, constructed, and arranged to monitor the effectiveness of the press braking system.
Clutch:
the coupling mechanism used on a mechanical power press component to couple the flywheel with the crankshaft to produce slide motion, either directly or through a gear train.
Two types of a clutch:
Part or Full revolution clutch
Device:
a press control or attachment that (a) restrains the operator from reaching into the point of operation; (b) prevents normal press operation if the operator's hands are within the point of operation; (c) automatically withdraws the operator's hands, if they are within the point of operation as the dies close.
Die:
the complete tooling component used for cutting, forming, or assembling material within its point of operation.
Feeding:
the process of placing or removing material within or from the point of operation.
Inch:
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 on the length of time the inch-operating means is operated; used by the die setter for setup of dies and tooling.
Jog:
an intermittent motion imparted to the slide by momentary operation of the drive motor, after the clutch is engaged with the flywheel at rest.
Secondary Operation:
press machine operation in which a pre-worked part is further processed
Slide:
the main reciprocating press component member. A slide may be called a ram, plunger, head, or platen.
Stroking Selector:
supply a means of selecting off, inch, single stroke, or continuos with the clutch/brake control.
Safety Blocks:
They disconnect the clutch-and motor-control circuits when blocks are removed from their storage pockets. Provide safety blocks with interlock plugs.
Full revolution:
Cannot disengage clutch until ONE complete stroke is made.Full revolution must be single stroke (anti-repeat).
Part revolution:
Can disengage clutch at any point along the cycle.
Foot Pedals - Treadles on mechanical power presses:
shall be protected to prevent unintended operation from falling or moving objects or by accidental stepping onto the pedal.
Mechanical Shears:
A metal working machine that is used primarily for shearing or cutting sheet metal. Ram moves a nonrotary blade at a constant rate past the edge of fixed blade. Can be mechanical or hydraulic with a full or part revolution clutch.
Brakes:
Metal working machine that forms parts through the use of dies attached to a plate ram or slide and a die bed. Primarily used to bend and form sheet metal but can also be used for punching, trimming, corrugating, and notching.
Roll formers and calendars are:
Machines which are capable of producing a bend across the width of a flat piece of metal by means of one or more rotating dies or rolls.
Forging hammers are:
A hot metalworking machine which strikes hot metal between two dies to form the metal into a desired shape. Other types of hot forging operations include rolling, upsetting, pressing, extruding and drawing.
Guarding flywheels:
Sheet, perforated, or expanded metal or woven wire, or with guard rails between 15 to 20 inches from flywheel rimToe board if within 12 inches of floor or extends into a pit
Guarding shatfing:
All exposed parts of horizontal shafting 7 ft. or less above the floor shall be guarded by a stationary casing, or by a trough..
Gears, sprockets and chains shall be guarded by one of the following method:
By a complete enclosure; orBy a standard guard as in paragraph (o), at least seven feet high, extending six inches above the mesh point of the gears.
Nip Points or Bites
a hazardous area created bt two or more mechanical parts rotating in opposite directions within the same plane and in-close interaction
Common practice in the design of point of operation safeguards is to consider:
any opening not exceeding 3/8 inch (9mm) as relatively safe