Lift table

Lifting tables ( Scissor ) are aids for lifting heavy loads. They are used in different areas of logistics.

Construction

A lifting platform has a deck or the top frame as a working surface on its upper side. Below he stands on a base frame. In this basic framework the storage of scissors consist of two legs of equal length, which move around an axis at the center of the leg run. Self-supporting base frame are needed for lift tables that are placed on non-planar surfaces.

On the fixed side the gap is connected to the base frame and the platform. On the non-locating are the equipped with casters scissors stock. The drive is hydraulic lifting tables of usually about aggregate driven cylinder, via a threaded spindle, via belt drives or rigid chains.

Designs

Lift tables are designed as single scissor lift, Tandemhubtische or double scissors. As Single Scissor Lift Tables Lift Tables are referred to in each of which a pair of scissors is used for each long side. As Tandemhubtische lift tables are referred to in each of which two pairs of scissors per long side next to each other so that the lift table has a greater length. As a double scissors lift tables are known in which two pairs of scissors are both on the long side over the other. A greater final height is reached.

Depending on the application, a lift table with chain curtain, bellows or PVC curtains are equipped. Also be equipped with railings, required if people are on the platform at a height > 500 mm is possible. For loading lift tables that are placed in front of a loading ramp to porch railing, which serve as a suitable fall protection.

Lift tables are operated as Anlagenhubtische, Montagehubtische, lift tables to transport goods or lift table and are subject to DIN EN 1570-1 from May 2012, submitted for lifting tables, the drive through no fixed stops, in addition to the Machinery Directive 2006/42/EC. If more than 2 stops to be approached, lift tables are in parts of EN 81 regulations for elevators, or a subsequent norm EN 1570-2, 1570-3 and EN.

Mentioned in the VBG14 quality requirements have been set according to the author the present report of 24 August 2009 of the Committee of Experts conveyor and storage technology of the German Social Accident Insurance with the entry into force of the Machinery Directive 98/37/EC overridden, or was the whole VBG 14 end 2003 overridden.

The dimensions of a lifting table are not limited to length and width, but result from the length and width of the lift table and the dimensions of the scissors, which must indeed find space under the lift table. Thus, the height of the table top and the base yield the so-called height. As effective stroke the difference between height and stroke end is called.

Operation

During the operation of a lifting table with a double shear - ie 2 scissors above the other - is considered to be relatively free of fluctuations, the lift table from three shears subject over each other to certain fluctuations that are often avoided only with side guides.

Load distribution

Lift tables are divided into lifting tables for uniform load distribution and lift tables for uneven load distribution.

Uniform load distribution means that 100 % of the load will be distributed over the entire surface of the table, and 33% of the half of the surface of the length, or 50% of the half of the surface of the widthwise. Rolling load with load distribution of 50 /50 per axis must act to 60% of rated capacity on the long side of the table, or 50% over the narrow side of the table. It should be noted that more must be centered when lifting and lowering of the lift table to the load center of gravity with the longitudinal axis of the table.

Uneven load distribution means that the lift table has the static load to 70 % of the area along or carry across. Rolling load on the long side must be at a load distribution of 50 /50 per axis 90 % of the total capacity. Rolling load on the narrow side must correspond to a load distribution of 50 /50 per axis 40 % of the carrying capacity of the table. Here, each assumes that the load is moving in the center of the table.

Security

Safety requirements for lifting tables are in EN 1570-1 May 2012 Publisher: set CEN (European Standards Committee). From the safety requirements are especially mentioned here:

• Deadman: Each lifting may raise or lower only as long as the corresponding switch is held down.
• Emergency: Each lifting must have at its operating unit a emergency.
• Safety contact strip: Each lifting must have on the table top base via a contact strip that triggers the touch and immediately stops the movement of the lift table, inasmuch as the defined Fußfreiräume can not be met and thus arise crushing and shearing points.
• Tränenblech: If the lifting table of people to enter the platform surface must be designed non-slip. A people - passenger ride is only for operators, as a companion to the load permitted.

Areas of application

Lift tables are used commercially as height compensation during the ergonomic workplace design or during the transfer of workpieces from one level to the other. Another application is the loading. Here lift tables can be used as a lift table to allow a smoother loading or unloading.