Special lift tables with check valves

These lift tables are used in the prototype construction of ATMs. Great importance was placed on the safety of both people and machines during their acquisition.

When designing each lift table, the safety factor must be adequately considered. It is not always enough to only consider the person using the lifting equipment; the load also requires special attention.

As mentioned earlier, prototypes for ATMs are produced on the scissor lift tables. In the prototype workshop, efforts are made to replicate the real conditions of the actual production process as closely as possible. Therefore, not only are prototypes developed and built, but the entire production process is simulated as accurately as possible.

ATMs have both significant weight and sensitive electronic components. The biggest threats to these components are voltage spikes, which can occur due to static discharge, for example. To eliminate any risk to the components, we have implemented two measures:

Grounding of all components

All components of the lift table are interconnected and grounded. This prevents static charge buildup caused by friction that could differ from the ground potential.

ESD rubber mat on the lift table

To protect the load being lifted from mechanical damage, a special ESD rubber mat has been placed on the platform. A normal rubber mat would insufficiently ground the ATMs. The ESD rubber mat is electrically conductive, grounding the load through the mat and the lift table. This eliminates the risk of voltage spikes.

There were several special safety considerations for these lift tables:

Overhanging loads

The frames to be lifted are larger than the actual lift table platform, posing a risk of an employee's foot getting trapped between the frame and the floor. Given the high load of up to 2,000 kg, there is a significant risk of injury. Therefore, we have implemented two safety measures:

1. The intermediate stop
The lift table is equipped with an adjustable intermediate stop switch. When an employee presses the lowering button, the lift table descends to just before the danger zone. The employee must then press the lowering button again to fully lower the table to the bottom position. This is intended to alert the employee to a potential hazard: After the scissor lift platform reaches the intermediate stop, the employee must check the danger area before the lift table can fully descend into the pit.

2. Super-flat safety stripes outside the lift table
Since human errors are inevitable, safety measures should not rely solely on the correct behavior of employees. Therefore, super-flat safety stripes (height: approx. 10 mm) have been installed around the lift table. If an employee steps into the danger zone, the safety stripes stop the lowering movement of the lift table. Further downward movement is only possible once the foot is removed from the danger area.

The combination of these two measures ensures nearly 100 percent safety for the feet of surrounding personnel.

Off-centre load on the lift table

The specified nominal load of the lift table applies only to an evenly distributed load on the platform. An off-center load reduces the load capacity. To ensure the lift tables are always loaded centrally, two inductive sensors have been built into the platform. These sensors align with the metallic edge of the frame and only allow a lifting movement if the load is applied centrally.

Electric check valves

Another risk with hydraulic systems is leakage. To prevent the platform from falling, our hydraulic lift tables and column lifts are equipped with burst pipe protections. These stop the platform during a pipe or hose break, preventing a fall. However, this safety measure can fail with small leaks. To avoid this hazard, we have installed electrically unlockable hydraulic valves on the cylinder. A downward movement of the lift table is only possible when the lowering button is pressed.

For more information on the advantages and disadvantages of various safety valves, read our article: ‘Safety devices on the lift table: Hydraulic valves’.

To get the production lines back in operation as quickly as possible, a solution was chosen that enables rapid commissioning.

Typically, the installation of a recessed, stationary lift table involves several steps:

1. Cutting a hole in the existing concrete floor.
2. Excavating the area under the concrete floor.
3. Shuttering the new pit.
4. Filling the shuttering with concrete.
5. Waiting four weeks for the concrete to fully cure.

The four-week waiting period was not acceptable in this case. Therefore, we offered an alternative solution: The lift table was delivered fully assembled in a metal tray. The tray is self-supporting and absorbs the loads from the lift table.

This method allowed the installation process to be shortened as follows:

1. Cutting a hole in the existing concrete floor.
2. Inserting the lift table with the pit tray and aligning it using leveling screws.
3. Filling the gap with non-expanding, fast-setting resin.
4. Commissioning the lift table.

Thanks to this approach, the installation of the lift tables, including the creation of the pit, was completed in just two days.

The control system of the lifting table has two features that differ from our standard controls:

1. Hand control from the ceiling 
A hand control unit has been installed, hanging from the customer’s ceiling. This allows for easy and ergonomic operation of the lift table.

2. Integrated indicator light
An indicator light has been integrated into the hand control unit, showing when the lift table is fully lowered. This is important because the load extends beyond the scissor lift platform. Without this light, it would be difficult to determine if the platform is fully lowered and if the frame can be moved away.