What is a Lift Table?
A lift table is exactly what its name implies. In its simplest form, it is a platform or table that can be raised or lowered to any height desired within its range of vertical movement.
The basic parts of a lift table are:
The base frame of a lift table
The base frame of a lift table supports the rest of the assembly. It has to be strong, rigid and stable. In most cases it is designed to be placed to the floor but it can also be built into a pit or supplied with wheels or casters or furnished with a fork lift chassie.
The lift table scissors
The scissors of a lift table provide true and level vertical motion while supporting the platform or top. The two sets of scissor legs are connected by shafts at the center pivot points and upper and lower hinged ends.
The top or platform of a lift table
The platform can be of any size that is compatible with the lift tables base frame and the scissors. Specifically, the platform can be no smaller than the length or with of scissors/base frame. Platforms can be larger than the scissors/base frame. Platforms can be furnished with a variety of options such as conveyor tops, turntables, tilt tops or tops equipped with clamps or special work fixtures.
The power pack
The lift tables power pack (most commonly electro hydraulic) consists of an electric motor, a hydraulic pump, a hydraulic tank, hydraulic cylinder, piping, valving and electrical control system. When the UP button is activated, the pump pumps fluid from the tank into the cylinders causing the piston and shaft to move. The piston shaft is mechanically linked to the leg assemblies and drives them to raise the platform. A check valve in the hydraulic line between the pump and the cylinder prevent fluid from flowing backwards so the platform will remain at whatever height it is at when the UP button is deactivated. When DOWN button is activated, a solenoid down valve opens, allowing hydraulic fluid to flow back to the reservoir. The motor does not run when the lift is lowering. The weight of the platform and gravity combine to create pressure in the cylinder that forces the fluid to flow back to the reservoir. A flow control valve located on the lowering valve VE 25, can be adjusted to provide the most desirable down speed. When DOWN button is deactivated, the lowering valve closes and the table remains at the same height it is at when the button is activated. The valve arrangement prevents the table from lowering if there is a power failure.
The control unit for a lift table
The standard control unit can be either pushbutton or foot control.
Throughout industry there is a continuing need to lift and position work pieces and materials. If workers are asked to accomplish this lifting and positioning without the aid of powered mechanical equipment, the result can vary from fatigue and low productivity to serious personnel accidents. Between these two extremes are injuries that relate to continuous, repetitive lifting and awkward positioning such as back pain and carpal tunnel syndrome. Lift tables are the ideal solution to lifting and positioning problems for the following reasons:
- Stable platform
Unlike hoists, cranes, or manipulators, lift tables provide a stable platform for lifting and lowering materials. The chance of accidentally dropping a work piece is much lower, and the danger of a suspended load swinging and causing injury to workers is eliminated.
- Infinite height adjustment
A lift table is designed to smoothly move up or down to any desired height and to maintain that height even if there is a power failure.
Lift tables can be provided with a wide range of options such as conveyors platforms, tilting platforms, and platforms with special fixturing such as clamps and automatic work positioning devices.
- Programmable movement
Movement can be programmed, and tables can be integrated into special handling systems.
Lift tables can be provided in portable configurations using wheels or casters and in semi portable configurations using a FLC (fork lift chassie).
- Wide vertical range
Lift table can be installed in pits for absolute zero lowered height or in floor height, floor mounted versions, or provided with multiple scissor legs for high lifting. Another option is the low profile lift table. Because of the low collapsed height, low profile lifting table need no pit installation, as they can be placed directly on the floor.
- Low maintenance
Lift tables are rugged, heavy-duty machines designed to provide years of reliable service with minimum maintenance.