Where to put the hydraulic power unit?

There are only two answers to the question where to place the unit: the unit is either placed inside or outside the lift table. And although this question seems so simple, the optimal arrangement should be considered in each individual case. This article first deals with the general advantages and disadvantages of the two options before giving our recommendations in specific cases.

Hydraulic power unit inside the lift table

When we mention 'internal power unit' in our quotations, we mean that both the control unit and the hydraulic power unit are placed inside the base frame of the lift table. This simplifies the installation of the scissor lift table . All that needs to be done is to attach the entire scissor lift on the designated transport lugs and to set it down at the desired location. The hydraulic line does not have to be laid anew and it saves bleeding the hydraulic circuit.
Another advantage of this type of installation is that the lift table takes up as little space as possible. The space required by the lift platform is limited to the geometric dimensions of the platform and separate space is not required for the power unit and for the line from the power unit to the lift table.

One disadvantage of an internal power unit is its accessibility for maintenance or in case of a malfunction. The drive unit is not accessible when the lift table is in the lowered position. For this reason, an inspection opening should always be provided above the power unit, especially in larger lift tables. The inspection opening allows access to the terminal board of the electric motor and so to the lifting of the platform. Subsequent repair work can then be carried out.

External hydraulic power unit

One advantage of hydraulic lift tables is the possibility to separate the drive unit from the actual lift table. This allows the hydraulic power unit and the control unit to be placed in an otherwise unused space, for example.
By placing the unit underneath a staircase or in a technical room, the scissor lift is also separated from its biggest source of noise. This is particularly important when compact units are used instead of under-oil units and when there are people permanently in the vicinity of the scissor lift table. Another advantage of external power units is the easy access to the components that are the most prone to failure.

Of course, this solution also has its disadvantages. With an external power unit, additional space for the drive unit is required in addition to the space for the lift table. As already mentioned before, it makes sense to use previously unused space under a staircase or similar for this purpose.
It should also be noted that a hose line must be laid between the hydraulic power unit and the cylinders of the lift table. This cannot be laid as flexibly as a simple electric cable. A tight bend and a complicated routing of the empty pipe must be avoided.

Specific applications

In most cases, you are free to choose where you want to place the hydraulic power unit. However, there are some applications where we would recommend specific installation locations.

Lift tables with a very narrow platform

In this case there can only be one logical answer. If the scissor lift table has a very narrow platform, it is simply not possible to place power unit inside the lift table. For this reason, you unfortunately have no choice but to place the power unit outside the scissor lift.
The same applies to flat lifting tables too, as the overall height of the lift table is not sufficient to accommodate the hydraulic power unit.

Lift tables in outdoor use

Lift tables used outdoors are often installed in a pit. The pit is equipped with a drain to prevent it from filling up with water. Unfortunately, we often find drains that are blocked by leaves or other dirt, rendering them useless.
Although the mechanics can still be relatively well protected against moisture by using a galvanised scissor lift table , this is unfortunately not the case with electrical controls and hydraulic power units. Therefore, we recommend the external placement of the drive unit. Another advantage is that one hardly needs to worry about low temperatures when the hydraulic power unit is located inside the building.

Lift tables with on-site load-handling

If you install a load-handling device on our lift table, it may be useful to provide an external unit. Especially if the load-handling device makes the installation of an inspection opening impossible or covers an existing inspection opening.

Transportable lift tables

All transportable lift tables, regardless of whether they are equipped with their own chassis or only with a simple base frame, should have an internal power unit. Otherwise the handling of the additional hydraulic hose will be a hassle in the future when moving the lift table.

Lift tables with pit installation in a hall

We would like to list this application, as it is one of the most common applications of a scissor lift table. Unfortunately, however, we cannot give you a clear recommendation for this situation. In most cases, we would advise you to use an internal unit, as the components we install have a very low probability of failure. Also the additional expenditure for the production of a corresponding empty pipe and the additional space required are not offset by the faster access in the event of damage.

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Comments (2)

  • von Gavel
    von Gavel
    Sehr geehrte Damen/Herren,

    welches sind die maximal möglichen Tieftemperaturbereiche für Hubtische mit eine separaten Hydraulik Aggregat?.

    Mit freundlichen Grüßen

    Roland von Gavel
    • Markus Janzen
      Markus Janzen
      Guten Tag Herr von Gavel,

      Standardmäßig verfügt das bei uns im Außenbereich eingesetzte Hydrauliköl noch bei -10°C über eine ausreichende Viskosität.

      Diese Temperaturgrenze kann allerdings noch weiter verschoben werden, so ist beispielsweise der Einsatz von Tankheizungen möglich, welche im Falle von niedrigeren Temperaturen garantiert, dass das Hydrauliköl im passenden Temperaturbereich gehalten wird.
      Wichtig ist in diesen Fällen, dass sich der Scherenhubtisch standardmäßig in der abgesenkten Position befindet (oder häufig genug verwendet wird) und die Leitungslängen nicht zu groß werden, damit das Hydrauliköl innerhalb der Leitungen und der Zylinder nicht zu stark herunterkühlt.

      Welche weiteren Maßnahmen erforderlich sind (z.B. weitere Isolierung der Leitungen) ist wiederum von den genauen Einsatzbedingungen und der Nutzung abhängig. Sollten Sie hier eine nähere Beratung wünschen, stehe ich Ihnen unter 05939/967 96 90 oder m.janzen@j-lifte.com zur Verfügung.

      Mit freundlichem Gruß
      Markus Janzen