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Ergonomic Assist Systems and Equipment

Glossary

Access Plate A removable cover to provide access to operating parts.
Actuator A device for converting potential energy into mechanical energy.
Air/Hydraulic A system, which uses compressed air to run hydraulic pumps.
Angular Creep Extremely slow speed movement of a tilter that is the result of normal leakage of fluid control valves.
Angular Travel The angular difference between the two tilting travel limits of the platform deck or forks, expressed in degrees.
Approach Ramp A rigid structure to span a gap between the floor and a platform.
Authorized Person Trained or qualified personnel approved or assigned to perform a specific duty or duties (see Qualified person or Trained person).
Automatic Landing Gate A landing gate that automatically opens or closes, respectively, as a lift platform arrives at or departs from subject landing.
Axle Load The dynamic load on the edge of a lift platform when a wheeled vehicle is rolled on.
B20.1 ASME Standard for Conveyors (VRC's)
Bearing Normally a low-friction needle roller or ball lined support for a rotating shaft.
Bellows Guards Fabric-like accordion skirting to enclose under the base and legs.
Bevel Toeguards Platform sides slanted inwardly at an angle of approximately 30 degrees from vertical in order to eliminate shear edges (commonly used in pit-mounted installations).
Bleed-Off Diversion of pressurized hydraulic fluid back to reservoir.
Bushing The lining of an inside surface to reduce friction.
By-Pass An alternative passage for fluid flow.
CO Customer Order
CS-202-56 Commercial Standard (-56=1956)
CSM Customer Supplied Material
CTD Cumulative Trauma Disorders
Cam Follower A hi-capacity roller bearing used to carry or guide load.
Center of Gravity The point at which a mass can be supported, in any position, and remain in equilibrium without tipping.
Check Valve A valve that allows fluid flow in one direction only.
Circuit Interconnected components through which energy or signals flow.
Clevis A structural mounting device to support a pin (i.e. used in attaching platform to legs).
Compressibility The change in volume of a fluid or solid when subjected to pressure.
Continuous Duty An electric motor rated to operate continuously.
Control Transformer An electrical device that changes the voltage of a circuit.
Control Voltage The voltage in the lift controls circuit.
Critical Components Those components whose absence or failure would cause the equipment, of which they are a part, to become inadequate or unsafe for its specific purposes.
Cross Tube A welded structural cross member between the legs of a scissors lift used to equalize loading between the legs.
Cycle For lift tables, one complete up and one complete down operation.
Cylinder A fluid vessel with piston and shaft that moves as fluid pressure increases or decreases.
Cylinder, Double Acting A cylinder in which fluid force can be applied to either side of the piston.
Cylinder, Ram A cylinder in which the piston and shaft have the same diameter.
Cylinder, Single Acting A cylinder in which the fluid force can be applied to only one side of the piston.
DC Direct Current (Electricity)
DHHS (or DHS) Department of Health and Human Services
Displacement The volume of fluid a pump moves in one cycle. The volume of fluid in a cylinder at full stroke.
Dock Lift A lift whose travel is generally 5 feet or less and which is used to load/unload material from trucks and transfer it to dock or ground elevation.
Down Valve A hydraulic control valve, which allow oil to return to the reservoir.
DU Bushing A pre-finished, high performance bushing used at the pivot points.
Ductile Describes material capable of sustaining not less than 5% elongation before it fractures.
Dynamic Load A moving load.
Edge Load The load on a platform edge as a result of off-center loading.
Electric Toeguard (toe sensor) A contact device that stops the down travel of a lift table when an obstruction is encountered.
Electric/Hydraulic A system which converts electric power to hydraulic power.
End/Side Axle Load Capacity The maximum amount of single axle load (in the case of rolling loads), which may be applied to the loading edge of the platform (end or side) when the lift is in its raised position.
End/Side Edge Load Capacity The maximum amount of static load that can be applied to the edge of platform (end or side) when the lift is in any raised position.
FPM Feet Per Minute
Flow Control Valve A valve which controls the rate of flow of hydraulic fluid.
Flow Rate The volume of fluid passing through a pipe or hose at a given time.
Four-Way Valve A valve which can direct fluid flow in 4 directions.
Hinged Bridge/Throw-over Plate A hinged transition plate attached to the edge of the platform to provide a bridge to a loading dock or truck bed.
Hydraulic Piping System The entire system of fluid conduits such as hose, pipe, tubing, etc. used to transfer hydraulic fluid between various operating components of the hydraulic systems such as pumps, valves, actuators, etc.
Interlock A device to prevent lift movement when a landing gate is not fully closed and to prevent the landing gate from being opened unless the lift platform is present at that landing.
Intermittent Duty An electric motor rating for part-time operation.
Jog To raise or lower the lift platform in short increments.
LSD Double Wide or Tandem Wide Scissors Lift
LSH Double Pantograph Scissors Lift
LST Double Long or Tandem Long Scissors Lift
LMPS Lift Manufacturers Product Section (MHI)
Landing A permanent working surface at a fixed elevation used for loading/unloading a lift or tilter device
Landing Gate A gate to control personnel traffic at a landing.
Lift Table A scissors lift device used to raise, lower, stack, convey and/or transfer material between two or more elevations and not limited to landings.
Lifting Capacity The rated load of a scissors lift applied as a uniformly distributed load
Limit Switch An electrical device, which by predetermined adjustment, limits the rotational or linear movement of a mechanism.
MH29.1 ANSI Standard for Industrial Scissors Lifts
MH29.2 ANSI Standard for Industrial Tilters
MH30.1 ANSI Standard for Dock Levelers
Maintained (Contact) Control Mode of control where movement starts when the control device is actuated and continues when the control device is released. Movement stops when either an appropriate limit switch is actuated or the Emergency Stop button is pressed. NOTE: Whenever a machine's control is maintained, an Emergency Stop button must be supplied and located where it can be reached by the operator. This applies when even a portion of a machine's operating sequence includes maintained control.
Maintenance Chock A device used to mechanically support a lift or tilter in the up position for maintenance.
Manual Control A control actuated by the operator, regardless of the means of actuation.
Manual Override A control that allows manual operation of an otherwise automatically controlled device.
Momentary (Contact) Control Mode of control where movement starts when the control device is actuated and stops when the control device is released (a.k.a. "Deadman" control).
Motor A device which converts electrical energy into rotational mechanical force.
N Narrow or Narrowed Scissors Lift
NEC National Electrical Code
NFPA National Fire Prevention Association
NEMA Classification National Electrical Manufacturers Association Standard.
NIOSH National Institute for Occupational Safety and Health
ODP Open Drip Proof Motor
OSHA Occupational Safety and Health Administration
Operator Trained person controlling the movement of the lift.
PSF Pounds Per Square Foot
PSI Pounds Per Square Inch
Pantograph Leg Section The articulated support mechanism characterized by a single pivot axis and commonly referred to as the scissors leg assembly.
Piston A cylindrically shaped part which fits within a cylinder and is actuated by fluid pressure.
Platform Ends The edges of the platform that are perpendicular to the scissors leg. The end dimension is considered the platform width.
Platform/Fork Length The platform or fork dimension as measured perpendicular to the hinged edge (tilt axis). This is considered the side of the platform or fork.
Platform/Fork Width The platform or fork dimension as measured parallel to the hinged edge (tilt axis). This is considered the end of the platform or fork.
Platform Sides The edges of the platform that are parallel to the scissors legs. The side dimension is considered the platform length.
Pneumatic Relating to air or another gas.
Pneumatic Piping System The entire system of pneumatic conduits such as hose, pipe, tubing, etc. utilized to transfer air or other gas between various operating components of the pneumatic system such as pumps, valves, actuators, etc.
Point Load A concentrated load.
Poppet A check or one-way valve.
Pressure Force per unit of area, usually expressed as pounds per square inch (psi).

Pressure Line
The line carrying pressurized fluid from the pump to the cylinders.
Pump A device which causes a liquid to flow under pressure. It converts mechanical force into hydraulic pressure.
Qualified Person A person, who by possession of a recognized degree, certificate, professional standing, or skill, and who by knowledge, training and experience has demonstrated the ability to deal with problems relating to the subject matter, the work or the project. (See Authorized Person and Trained Person).
Quick Disconnect A means of rapidly connecting and disconnecting electric or hydraulic lines.
RPM Revolutions Per Minute
Rated Capacity The maximum uniformly distributed load, which can be applied according to the manufacturer's specification.
Rated Load The maximum capacity as specified by the equipment nameplate.
Relief Valve A valve that operates at the preset pressure to allow the escape of fluids.
Reservoir A vessel for storage of hydraulic fluid, which is not under pressure.
Return Line A line used to carry hydraulic fluid from the cylinders back to the reservoir.
Rollover Capacity The maximum amount of single-axle load, which may be rolled over, the platform surface when the lift is in its fully closed position.
SAE Society of Automotive Engineers
SME Society of Manufacturing Engineers
Scissors Lift A raising/lowering device that is supported or stabilized by one or more pantograph leg sections.
Semi-Live Portability A lift table with non-castered wheels at one end and a wheeled skid spotter at the opposite end.
Shall The word "shall" is to be understood as mandatory.
Should The word "should" is to be understood as advisory.
Signal A command to or feedback from an actuator or sensor.
Single Acting Cylinder See Cylinder, Single Acting.
Static Load A stationary load.
Strength Factor The ratio of ultimate strength of a material to its design stress and maximum rated capacity.
Stroke The length of travel of a piston or piston rod.
Strong Back A cross member on a scissors lift used to equalize loading between the scissors legs.
Suction Line The hydraulic line from the reservoir to the pump inlet (suction side).
TEFC Totally Enclosed Fan Cooled Motor
TENV Totally Enclosed Non-Ventilated Motor
Throw-Over Plate See Hinged Bridge/Throw-Over Plate
Thrust Angle (Strong Back) A cross member on a scissors lift where the cylinder pushes on to create the travel.
Torque Twisting force (expressed in inch pounds or foot pounds).
Trained Personnel Personnel who have been trained by a qualified person and have demonstrated the ability to perform a particular function on or around a scissors lift or tilter. (See Authorized Person and Qualified Person)
Trunnion See Strong Back or Thrust Angle.
Two-Way Valve A valve which can direct fluid flow in two directions.
UL Underwriters Laboratories (Inc.)
VRC Vertical Reciprocating Conveyor
Valve A device which directs and controls the pressure and flow rate of a fluid.
Velocity Fuse hydraulic valve which senses rapid increase in the speed of the fluid (i.e. a break in a hydraulic line) and locks the fluid in the cylinder to prevent the lift or tilter from falling.
Vertical Creep Extremely slow speed movement of a scissors lift that is the result of normal, internal leakage of the fluid control valves.
Vertical Travel The difference between fully raised height of the platform deck and fully lowered height of the platform deck.
Volume The three-dimension size of a space of chamber (cubic inches). The output of a pump as expressed in gallons per minute (gpm)
W Wide or Widened Scissors Lift
Watt A measure of electrical energy (volts x amperes).
Wheel Chock A wedge-shaped device to prevent wheels from rolling.