There are basically two options for locating the hydraulic power unit: inside or outside the lift table.
Although this choice seems simple, it should be carefully considered for each application. The optimal arrangement depends on various factors such as space, maintenance access and noise pollution.

Internally installed hydraulic unit: Advantages and challenges

Single scissor lift table with internal power unit

In a scissor lift table with an internal power unit, the hydraulic unit and the control system are installed in the base frame of the lift table.

Advantages of internal placement

Easier assembly: The lift table can be set down directly at the installation site using the transport lugs provided. Since no hydraulic lines need to be laid, there is no need to bleed the hydraulic circuit.
Space-saving solution: The space required by the lift table largely corresponds to the platform dimensions, as no separate installation area is needed for the unit.

Disadvantages of internal placement

More difficult accessibility for maintenance or faults: If the lift table is in the lowered position, the drive unit cannot be reached directly. To avoid this, an inspection opening should be provided above the unit, especially for larger lift tables. This allows access to the terminal board of the electric motor so that the platform can be raised and further repair work can then be carried out.

Externally installed hydraulic unit: Advantages and disadvantages

Unlike other designs, hydraulic lift tables offer the option of physically separating the drive unit from the lift table.

Advantages of external installation

Reduced noise pollution: By placing the unit externally, the lift table is decoupled from its main source of noise. This is particularly advantageous when compact units are used instead of under-oil units and people are constantly in the vicinity of the lift table.
Better accessibility for maintenance or faults: The components that are most prone to faults are more easily accessible when placed externally, which makes maintenance and repair work considerably easier.

Disadvantages of external installation

Increased space requirement: In addition to the space for the lift table, additional space must be planned for the unit. It may make sense to use unused areas for this, such as under a staircase.
Laying the hydraulic line: A hose line must be laid between the external hydraulic unit and the cylinders. This is less flexible than an electric cable. Sharp bends and complex hose routing should be avoided.

Placing the hydraulic power unit correctly: Practical examples

In many cases, you can decide for yourself whether the hydraulic power unit is placed internally or externally. However, under certain conditions, a specific placement is recommended.

Lift tables with very narrow platform

For scissor lift tables with a particularly narrow platform, it is not possible to place the hydraulic unit internally. In these cases, the unit must be placed externally.

The same applies to flat lift tables, as their low height is not sufficient to integrate the hydraulic unit into the base frame. Here, too, external positioning is required.

Lift tables for outdoor use

Lift tables for outdoor use are often installed in pits. To prevent the pits from filling with water, they are equipped with a drain. In practice, however, the drains can become blocked by leaves or dirt, preventing them from functioning reliably. As a result, water can accumulate in the pit.

While the steel components of a lift table can be relatively easily protected against moisture by hot-dip galvanizing, protecting electrical controls and hydraulic units is more challenging. Therefore, it is recommended that the drive unit be located externally – ideally in a protected indoor area.

An additional advantage of placing the unit inside a building is protection against frost and extreme temperatures.

Lift tables with on-site load pick-up

If a load pick-up device is to be mounted on the lift table, the use of an external hydraulic unit may be useful. This applies in particular if the load pick-up device prevents the installation of an inspection opening or covers an existing inspection opening.

Portable lift tables

All portable lift tables – whether they have their own chassis or are mounted on an elevated base frame – should be equipped with an internal hydraulic power unit. An external power unit can restrict the mobility of the lift table, as the power unit and hydraulic lines have to be moved as well as the table itself.

Scissor lift tables for pit installation in halls

This installation situation often occurs with scissor lift tables. Without precise knowledge of the individual operating conditions, we cannot give any generally valid recommendations, but in many cases, several factors speak in favor of an internal hydraulic unit.

On the one hand, the additional space required for the unit and the laying of the hydraulic lines through a conduit is eliminated, and on the other hand, the components we install have a very low probability of failure.

Do you have any questions?

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? Phone: +49 5939 96796-90
? E-mail: info@j-lifte.com

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