Corporate Safety and Environmental
VARIOUS TYPES OF RESISTANCE WELDERS Rocker Arm, Seam, and Spot Welder
MULTIHEAD RESISTANCE WELDER
INSTALLATION – All equipment is to be installed by qualified electrician. There must be a safety-type discon- necting switch, a circuit breaker or a circuit interrupter to open each power circuit to the machine conven-
iently located at or near the machine.
Ignitron tubes used in resistance welding equipment must be equipped with a thermal protection switch. Employees assigned to operate resis- tence welding equipment must be properly trained and judged competent to operate the equipment. All controls of automatic or air and hydraulic must be arranged or guarded to
prevent accidental activation by the operator.
NONPORTABLE SPOT AND SEAM For operator safety, all external weld initiating control circuits shall operate
on low voltage (not over 120 volts).
Stored energy or capacitor discharge resistance welding equipment and con- trol panels involving voltages of over 550 volts must be insulated and pro- tected by complete enclosures with interlocked doors with contacts wired into the control circuit. These interlocks must interrupt power and short circuit
all capacitors when the door or panel is open.
A manual switch or other suitable pos- itive device, along with other mechani- cal interlocks or contacts, must be in-
stalled as an additional safety measure.
All doors and access panels of all resistance welding machines and con- trol panels are to be kept locked and interlocked to prevent access to live
portions of the equipment by un-
All press welding machines must be guarded where there is a possibility of the operator’s fingers being under the point of operation by such devices as: Electronic eye safety circuits.
Two hand controls similar to punch
All chains, gears, operating bus
linkage and belts must be protected
VARIOUS TYPES OF GUARDING
Where practical, shields guards of safety glass or suitable fire-resistant plastic, shall be installed to guard against flying Additional shields or curtains shall be installed as necessary to protect passing
persons from flying sparks.
All operators and attendants shall use transparent face shields or goggles to protect their eyes while operating resis-
tance welders or resistance brazing
FOOT SWITCHES All foot switches shall be guarded to
prevent accidental operation of the
STOP BUTTONS Two or more emergency stop buttons shall be provided on all special multispot welding machines,
including 2-post and 4-post weld
SAFETY PINS On large machines, four safety pins with plugs and receptacles (one in each corner) shall be provided so that when the safety pins are re- moved and inserted into the ram or
platen, the press becomes inopera-
GROUNDING WHEN?: When technically practical. WHAT?: The secondary of all welding transformers used in multispot, projection, HOW?: By permanently grounding
secondary current circuit.
GROUNDING When not technically practical: Use a center tapped grounding reactor connected across the sec- ondary or use a safety disconnect switch in conjunction with the welding controls. The safety discon- nect shall be arranged to open both
sides of the line when welding current
PORTABLE WELDING MACHINES Counterbalance: All portable welding guns shall have suitable counter- balanced devices for supporting the guns, including cables, unless the design of the gun makes counter-
balancing impractical or unnecessary.
PORTABLE WELDING MACHINES Safety Chains: All portable welding guns, transformers and related equipment that is suspended from overhead structures, eye beams, trolleys, etc. shall be equipped with safety chains or cables capable of supporting the total shock load in the event of failure of any
component of the supporting system.
PORTABLE WELDING MACHINES Clevis: Each clevis shall be capable of supporting the total shock load of the
suspended equipment in the event of
PORTABLE WELDING MACHINES Switch guards: All initiating switches, including retraction and dual schedule switches, located on the portable welding gun shall be equipped with suitable guards capable of preventing accidental initiation through contact with fixtures, operator’s clothes, etc.
The initiating switch voltage shall not
PORTABLE WELDING MACHINES Moving Holder: The movable holder,
where it enters the gun frame, shall have sufficient clearance to prevent the shearing of fingers carelessly placed on the operating movable holder.
PORTABLE WELDING MACHINES Grounding: The secondary and case of
all portable welding transformers shall be grounded by center tapped secondary or by a center tapped grounding reactor connected across the secondary.
Ventilation and Flash Guard: Flash
welding machines shall be equipped with a hood to control flying flash. In cases of high production, where materials may contain a film of oil and where toxic elements and metal fumes are given off, ventilation shall be pro-vided in accordance with 1910.252(c).
Fire Curtains: For protection of the operators of nearby equipment, fire-resistant curtains of suitable shields shall be set up around the machine and in such a manner that the operators movements are not hampered.
PERIODIC INSPECTION SHALL BE MADE BY QUALIFIED MAINTENANCE PER- A CERTIFICATION RECORD MUST BE THE SIGNATURE OF PERSON CONDUCTING THE INSPECTION
SERIAL NUMBER OR IDENTIFIER OF EQUIPMENT INSPECTED
OPERATORS SHALL BE INSTRUCTED TO REPORT ANY EQUIPMENT DEFECTS TO HIS SUPERVISOR AND THE USE OF THE EQUIPMENT DISCONTINUED UNTIL
SAFETY REPAIRS HAVE BEEN COM-