THE MAIN LIFTING SCREW SHALL HAVE A MINIMUM DIAMETER OF 2.25 INCHES AND SHALL BE PROTECTED FROM DAMAGE BY A STEEL ENCLOSURE ON A MINIMUM OF FOUR SIDES. BELLOWS SHALL NOT BE ACCEPTABLE AS A MEANS OF SCREW PROTECTION AS IT DOES NOT PROVIDE PROTECTION AGAINST POSSIBLE STRUCTURAL DAMAGE.

THE MAIN LIFTING SCREW SHALL BE PROTECTED FROM DIRECT EXPOSURE TO DUST, DIRT, PAINT, AND OTHER CONTAMINANTS BY A-NYLON PROTECTION BAND.

THE MAIN LIFTING SCREW SHALL HAVE AN AUTOMATIC LUBRICATION SYSTEM SUPPLYING GREASE TO THE LIFTING SCREW/NUT ASSEMBLY.

GUIDE ROLLERS FOR GRIPPER FORK CARRIAGE SHALL HAVE SEALED ANTI-FRICTION BEARINGS.

EACH COLUMN SHALL BE EASILY MOVEABLE ON FOUR WHEELS CONSISTING OF: TWO FIXED STEEL WHEELS WITH AXLE BEARINGS MOUNTED ON THE STRADDLE LEGS AND DUAL EXTENDABLE AND STEERABLE NYLON WHEEL ASSEMBLY MOUNTED AT THE REAR. REAR WHEEL ASSEMBLY SHALL BE NON-LOADING AND PROVIDE 180 DEGREE STEERING. HARD POLYMER PLASTIC WHEELS SHALL NOT BE ACCEPTABLE, BECAUSE THEY PICK UP DEBRIS FROM THE SHOP FLOOR, WHICH MAKE THEM DIFFICULT TO MANUEVER.

THE REAR DUAL WHEEL ASSEMBLY SHALL BE DESIGNED TO BE SELF RETRACTING, ELIMINATING ANY POSSIBILITY OF AN OPERATOR LEAVING THE TRANSPORT WHEELS IN THE RAISED POSITION WHILE LIFTING A VEHICLE.

ALL WHEEL BEARINGS SHALL BE SEALED ANTI-FRICTION TYPE.

LIFT OPERATION CONTROLS SHALL BE MOUNTED ON EACH COLUMN. LIFTING SYSTEM WILL BE OPERABLE FROM ANY OF THE FOUR COLUMNS. CONTROL CIRCUIT SHALL BE 110 AND 24 VOLTS.

A SELECTOR SWITCH SHALL BE PROVIDED TO SELECT INDIVIDUAL, PAIRED OR SYNCHRONOUS FUNCTION. SYSTEM SHALL ALSO ALLOW FOR USE OF JUST TWO LIFTING COLUMNS WITHOUT CONNECTION OF ALL FOUR OR SIX LIFTING COLUMNS WITH THE USE OF DUMMY PLUGS.

A FUSIBLE MAIN DISCONNECT SWITCH SHALL BE PROVIDED TO CONTROL SOURCE POWER AND SHALL HAVE KEYLOCK TABS TO PERMIT LOCK-OUT WHEN THE LIFT IS NOT IN USE OR WHEN PERSONNEL ARE WORKING UNDER THE VEHICLE. EACH COLUMN SHALL HAVE A SET OF "UP" AND "DOWN" CONTROLS FOR INDIVIDUAL OR SYNCHRONOUS OPERATION.

A MINIMUM OF 50 FEET OF MAIN POWER CABLE SHALL BE PROVIDED.

SYSTEM SHALL USE A HELICAL ACME THREADED MACHINE SCREW TO INSURE MAXIMUM SELF-LOCKING CHARACTERISTICS. DESIGN OF SUCH SCREW SHALL BE SUCH AS TO PROVIDE MAXIMUM FRICTION BETWEEN SCREW THREADS AND CORRESPONDING LOAD BEARING NUT THREADS. THIS HIGH FRICTION SHALL GIVE THE SCREW NON-REVERSIBLE CHARACTERISTICS.

BALL SCREWS, HYDRAULIC CYLINDERS AND OTHER NON SELF-LOCKING MECHANISMS SHALL NOT BE ACCEPTABLE, BECAUSE THEY DO NOT POSSESS SELF-LOCKING CHARACTERISTICS DURING THE ASCENT OR DESCENT MODE, AND UPON A LOCKING MECHANISM FAILURE, THE SYSTEM MAY GRAVITATE DOWN.

THE LOAD BEARING NUT SHALL BE BRONZE AND MATED WITH THE MACHINE SCREW.

SAFETY NUT SHALL BE STEEL AND SHALL BE MATCHED AS A MARRIED PAIR TO THE BRONZE LIFTING NUT AND THE ENTIRE NUT SYSTEM SHALL INCORPORATE A WEDGE BRAKE LOCKING SYSTEM.

THE LIFT SHALL INCLUDE AN AUTOMATIC LEVELING SYSTEM (ISO-LEVELING), WHICH THROUGH A MICROPROCESSOR, MONITORS THE EXACT POSITION OF ALL OF THE LIFTING COLUMNS AND WILL AUTOMATICALLY ADJUST THE POSITION OF THE INDIVIDUAL LIFTS TO MAINTAIN NO GREATER THAN A 1 AND 3/8" HEIGHT DIFFERENTIAL BETWEEN COLUMNS. THE LEVELING SYSTEM SHALL ALSO SHUT DOWN THE ENTIRE LIFT IN THE EVENT OF AN OUT OF LEVEL CONDITION, WHICH CANNOT BE CORRECTED. POTENTIOMETER SYSTEMS SHALL NOT BE ACCEPTABLE AS THEY ARE SUBJECT TO ENVIRONMENTAL DUST AND DEBRIS, CAUSING THE SYSTEM TO BECOME INOPERABLE, REGISTERING INVALID FAULTS IN THE LEVELING SYSTEM.

MOTIVE BUTTONS SHALL BE OF A "DEADMAN" TYPE DESIGN TO PREVENT LIFT OPERATION WHEN THEY ARE NOT PUSHED.

MAGNETIC-THERMAL RELAYS SHALL PROTECT MOTOR AND ELECTRICAL CIRCUITS AGAINST OVERHEATING.

INSTANT TRIP PROTECTION IN THE MAIN DISCONNECT SWITCH SHALL BE PROVIDED TO INSURE AGAINST SHORT CIRCUITS IN CABLES AND ELECTRICAL WIRING.

CABLE HOLD DOWN BRACKETS SHALL BE OF STEEL TO PROVIDE SAFE STORAGE OF CABLES WHEN UNIT IS NOT IN OPERATION.

MOTIVE POWER SHALL BE PROVIDED BY HIGHT-TORQUE, TOTALLY ENCLOSED, FAN-COOLED MOTORS WITH A MINIMUM HORSE POWER OF THREE (3) HP., DRIVING A GEAR REDUCER POWERING A MACHINE SCREW WITH TRAPEZOIDAL THREAD. THE PITCH OF SAID SCREW SHALL BE SUFFICIENT AS TO GIVE THE SCREW SELF-LOCKING ANTI REVERSING CHARACTERISTICS. MOTOR SHALL HAVE A DUAL VOLTAGE POSSIBILITY OF 220/440 VOLTS AC THREE PHASE.

THE VERTICAL FORCE OF THE LIFTING SCREW SHALL BE TRANSMITTED TO THE FORK CARRIAGE BY MEANS OF A LOAD NUT WITH A FOLLOWER STEEL SAFETY NUT TO ACCOMMODATE LOAD IN EVENT OF EXCESSIVE WEAR OR FAILURE OF THE LOAD NUT PER ANSI B 153.1 (1990) TO INCLUDE AN INDEPENDENT WEDGE BRAKE LOCKING SYSTEM.

MOTION FAULT DETECTORS SHALL BE PROVIDED TO DEACTIVATE THE LIFTING SYSTEM IN THE EVENT ANY MAIN LIFTING CARRIAGE CEASES TO MOVE WHEN SYSTEM IS IN "RAISE" OR "LOWER" MODE.

ALL POWER TO THE LIFT SYSTEM SHALL INSTANTLY AND AUTOMATICALLY DEACTIVATE AND THE COMPUTER SHALL CAUSE A FAULT IN THE EVENT OF COLUMN FAILURE, CONTROL MALFUNCTION, OR CABLE DAMAGE.

12.10 UPPER AND LOWER LIMIT SAFETY SWITCHES SHALL BE PROVIDED TO CONTROL THE LIMITS OF SAFE TRAVEL OF THE LIFTING CARRIAGE ASSEMBLY. THE SYSTEM SHALL BE DESIGNED SO THAT ALL JACKS WILL SHUT DOWN WHEN THE FIRST LIMIT SWITCH IS ACTIVATED. THIS PROVIDES A REDUNDANT SAFETY BASKUP SYSTEM WHEREAS IF THE FIRST LIMIT SWITCH FAILS, THE NEXT LIMIT SWITCH WILL SHUT DOWN ALL OF THE JACKS.

A RED EMERGENCY MUSHROOM PUSH BUTTON SHALL BE LOCATED ON EVERY COLUMN ON THE CONTROL CABINET TO PERMIT MANUAL DEACTIVATION OF ALL THE LIFTING COLUMNS.

A PHASE RELAY SHALL AUTOMATICALLY DEACTIVATE THE SYSTEM IN THE EVENT OF A PHASE CHANGE IN THE POWER SUPPLY.

AN ADJUSTABLE HEIGHT LIMITING DEVICE SHALL BE LOCATED INSIDE THE MASTER CONTROL BOX. THIS DEVICE SHALL ALLOW THE OPERATOR TO CONTROL UPPER LIMIT SHUT OFF OF THE LIFT BETWEEN THE RANGE OF 40" TO 67" WITH THE ADJUSTMENT OF AN ADJUSTING SCREW. E-PROM SYSTEMS SHALL NOT BE ACCEPTABLE, AS THEY DO NOT ALLOW ADJUSTMENT ON THE SITE WITHOUT COMPLETELY REPLACING THE E-PROM ITSELF.

THE LIFTING SYSTEM SHALL INCORPORATE A DUAL EMERGENCY OPERATING AND LOWERING SYSTEM TO OPERATE OR LOWER THE LIFT IN THE EVENT OF ELECTRICAL CONTROL VOLTAGE FAILURE.

THE LIFT SHALL INCLUDE A SELF-DIAGNOSTIC TROUBLESHOOTING SYSTEM. THIS SYSTEM SHALL CONSIST OF THREE LIGHTS ON THE MASTER PANEL, WHICH SHALL PROVIDE A CODED SIGNAL INDICATING UP TO FOURTEEN DIFFERENT FAULT CONDITIONS. THE CODES SHALL BE DISPLAYED ON THE PANEL AS WELL AS IN THE OPERATORS MANUAL INDICATING THE TYPE OF FAULT INDICATED.

THE LIFT SHALL ALSO INCLUDE A CYCLE COUNTER WHICH WILL ALLOW THE USER TO MONITOR CYCLES AS PART OF AN EFFECTIVE PERIODIC MAINTENANCE SCHEDULE.