There are situations that require a bit of positive pressure from the outside. This statement also applies to lift tables. In this reference article, we demonstrate the measures we have taken to prevent the deflection of a 6-meter-long shaft.
The challenge: Deflection of a long shaft
The end customer faced the following challenge: In their production, PVC tarps are wound onto a 6-meter-long shaft. Due to the length of the shaft and the increasing weight of the tarp, the shaft was bending. Unfortunately, this bending exceeded the acceptable limits for the winding machine.
The solution: Hydraulic lift table to support the shaft
To prevent the deflection of the 6-meter-long shaft, we offered the customer a hydraulic lift table that supports the shaft by generating counterpressure.
In principle, a small scissor lift table positioned in the middle of the bending shaft would have sufficed. However, the customer desired a wide support for the PVC tarp, leading us to opt for a tandem lift table.
Precise support for the shaft
On the very long and narrow platform, the customer installed several support rollers for the winding machine. The scissor lift platform applies a defined pressure from below against the 6-meter-long shaft, thereby preventing the shaft from bending.
The precise pressure height is determined using a force-displacement diagram. The pressure value is adjusted via an adjustable pressure relief valve and the displacement measurement is conducted using a cable length sensor.
Easy relocation
Once the PVC tarp is fully wound, the full shaft is replaced with an empty one. To ensure the lift table is not in the way during the exchange, we equipped it with forklift pockets.
For subsequent repositioning, flat irons with appropriate mounting holes were attached to the underside of the lift table. This simple solution allows the lift table to be quickly and efficiently moved to a new location, significantly reducing setup times.
Deviation from our standard design
To simplify the control loop, we opted for a vertical arrangement of the lift cylinders, differing from our standard lift table design.
