In this article, we aim to present common mistakes in the planning and implementation of projects involving hydraulic goods lifts and lift tables. Additionally, you will receive practical tips to successfully overcome these challenges. Our goal is to provide you with the best possible support to ensure your projects run smoothly.
Of course, this article cannot cover every challenge you may encounter. However, the examples provided are intended to serve as a guide and point of reference. As the famous inventor Thomas Alva Edison once said:
“That’s the wonderful thing about a mistake: you don’t have to make it twice.”
Empty conduits and core drillings
Empty conduits and core drillings are essential for the installation of hydraulic goods lifts and scissor lift tables. Before diving into the most common issues, let us briefly explain why empty conduits and core drillings are so important:
What are empty conduits and core drillings used for?
If the hydraulic power unit and the control system are installed within the pit, empty conduits and/or core drillings are necessary to:
- bring the power supply from outside into the pit.
- route cables from the control system to the operating stations and safety interlocks.
If the hydraulic power unit is installed externally, they are required to:
- lay electrical and hydraulic lines between the power unit and the lift table.
- install additional cables between the control system, operating stations and safety interlocks.
Mistake #1: Missing empty conduits
A common mistake is the absence of empty conduits. While the construction phase often includes consideration for the pit itself, the necessary supply lines are frequently overlooked.
As a result, additional core drillings have to be performed later, leading not only to extra costs but also often resulting in less optimal routing options.
Mistake #2: Incorrect positioning of empty conduits
Another crucial aspect is the positioning of empty conduits. Our planning typically specifies the empty conduits in the lower third of the pit. In this location, they must pass through the foundation, which may, in some cases, require additional measures such as waterproofing against groundwater.
However, empty conduit positions are often changed without prior consultation and they are placed just below the future floor level. While this simplifies construction, as the conduits can be embedded in the foundation, it may lead to collisions between the lift table platform and the cables, ultimately preventing successful commissioning
Tips for avoiding mistakes:
- Ensure that empty conduits and core drillings are accounted for during the planning phase.
- If the proposed positions are problematic for construction, contact us early. We can evaluate alternative solutions to determine the optimal placement.
Incorrect dimensions
Deviation from the execution plan
When we talk about deviations, we don’t mean minor differences within standard tolerances but significant discrepancies from the execution plan. For example, a goods lift with a cabin length of 2 meters simply cannot fit through a ceiling opening that is only 1.9 meters long.
Such deviations often result in:
- significant delays,
- additional costs and
- labor-intensive on-site adjustments.
Why platform dimensions are not sufficient as pit dimensions
A common mistake is assuming that the platform dimensions of the lift table correspond to the clear internal dimensions of the pit. This leads to pits that are too small because manufacturing tolerances and clearances are not considered. In the best case, the lift table barely fits; in the worst case, it doesn’t fit at all.
Bigger is not always better
Excessively large reserves can also be problematic. A pit that is 100 to 200 mm deeper than planned can create issues such as:
- The need for labor-intensive backfilling, or
- The requirement for an additional substructure for the lift table.
Both measures incur avoidable costs and delays during commissioning.
Our recommendation: Reserves are already accounted for in our execution plan. If additional tolerances are desired, limit them to 10 to 20 mm, as we can easily compensate for this space using filler plates.
Shaft dimensions and the declaration of conformity
Even when planning shaft width and length, too much space can be problematic. This primarily affects compliance with legal standards and safety requirements, rather than the assembly itself.
Our execution plan typically includes a clearance of about 15 mm around the platform. According to EN 1570-1, the gap between the lift table platform and the adjacent shaft wall must not exceed 30 mm. If this limit is exceeded, platform guardrails may need to be installed. Without these, the fundamental safety requirements cannot be met, and a declaration of conformity cannot be issued. Without this declaration, the lift table cannot be legally operated within the EU.
Tips for avoiding mistakes:
- Follow the execution plan: The specified dimensions are optimized to ensure proper assembly and compliance with regulations.
- Coordination for adjustments: Inform us early about planned deviations. This allows us to assess alternatives and develop appropriate solutions in time.
- Request accurate drawings: If you are missing the pit or shaft dimensions, simply reach out to us. We will be happy to provide the necessary documents.
Overly generous tolerances
In construction, deviations are often unavoidable. Common tolerances are generally unproblematic in many areas — for example, in a living room layout, a deviation of one or two centimeters from the plan typically has little impact.
The situation is different for elevator shafts: Even minor deviations can have significant consequences.
Why precision is crucial
As mentioned earlier, a deviation of just 15 mm can jeopardize the conformity of the entire elevator system. In such cases, the system cannot be put into operation because it does not meet legal requirements.
This often necessitates complex and costly adjustments — either to the elevator shaft or to the hydraulic lift itself. These corrections not only incur additional expenses but also cause delays in the construction process.
Tips for avoiding mistakes:
The risks mentioned can be effectively minimized through meticulous planning and careful execution. Even small improvements in execution accuracy can help avoid expensive rework and delays.
Landing doors and protrusions in the shaft
The selection and proper installation of landing doors often present a significant challenge in practice. Mistakes in this area can lead to serious issues.
Choosing the right landing door
Elevator doors must have a smooth interior surface to avoid protrusions. Protrusions could cause the platform or transported loads to snag.
This also means that an elevator door inside the shaft may only have a recessed handle — traditional door hardware is not permitted.
Correct installation of doors
If the elevator door is not installed flush with the interior of the shaft, a protrusion can form at the door lintel. Protrusions increase the risk of loads becoming caught and damaged.
For this reason, the entire interior surface of the elevator shaft must be smooth and free of any protrusions.
What to do if protrusions are unavoidable?
If a protrusion is technically unavoidable, the installation of a deflector plate is required. This plate must not exceed an inclination of 15° relative to the vertical axis.
Electrical issues
In practice, three typical electrical mistakes often occur, which can compromise the functionality and safety of the system:
- Missing power supply.
- Improperly secured power supply.
- Direct connection to a sub-distribution panel or fuse box.
Below, we explain these issues, their consequences and appropriate solutions.
Missing power supply
Without an appropriate power supply, neither our column lifts nor scissor lift platforms can be operated. A proper connection is therefore absolutely necessary.
Exception: Lift tables equipped with a hand pump can be operated manually.
Improperly secured power supply
This issue is less obvious because the system generally functions. Problems arise only when the phases are individually fused and there is a disruption in the power supply.
If only one of the three phases is disconnected during a fault, the three-phase motor remains energized through the other two phases. This condition can damage the motor.
The solution: Always use a three-pole circuit breaker for protection. In the event of a fault, it disconnects the entire power supply. Once the fault is resolved, the system can be safely reactivated.
Direct connection to a sub-distribution panel or fuse box
This issue is crucial for the safety of maintenance and service personnel. The system must not be directly connected to a sub-distribution panel or fuse box, as the power supply must be fully disconnected and secured against reconnection during maintenance or repair work.
The system must either use a plug connection that can be secured with a lock or have a lockable main switch.
Installation
The installation of scissor lift tables and goods lifts requires careful planning to avoid common mistakes. Here are the three most frequent challenges that can arise — and how to address them:
Underestimated weight
Our lift tables are robustly and solidly built to ensure maximum reliability. However, this means that heavy equipment is often required for installation. Larger telehandlers, forklifts or similar machinery are commonly needed for the process. The area around the installation site must be able to support the wheel loads of such equipment.
Careful planning ensures that the necessary equipment is available and the ground is adequately prepared.
Restricted access
In some projects, access to the installation site is spatially limited. For example, a 2 x 2-meter lift table cannot fit through a 1-meter-wide door.
Our solution: Notify us early if such restrictions are anticipated. We can manufacture the lift table with a split platform, for instance, to facilitate installation. However, it is essential that we receive this information in advance so the adjustments can be incorporated during the design phase.
Optimal timing
The right installation timing depends on the construction project and should be planned in advance — especially if we are also providing the elevator enclosure. Poor timing can lead to unnecessary rework or complications.
Examples of installation timing:
- Early installation: Early installation of the lifting system makes sense if:
- The final flooring cannot support the wheel loads of heavy equipment.
- Access is no longer possible after certain construction phases (e.g. roof closure).
- Late installation: In most cases, installation is recommended towards the end of the construction phase. Benefits include:
- Final landing levels are established, allowing optimal adjustment of the elevator.
- Trip hazards are avoided.
- No additional site visits are necessary.
Our recommendation:
- Early communication: Inform us promptly about special requirements or constraints.
- Flexible solutions: Leverage our expertise to discuss customized adjustments and ensure all conditions are met.
With careful planning and timely coordination, we can ensure a smooth and efficient installation process together.
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