When discussing elevator safety systems, two components are almost always mentioned: the upper final limit switch and the lower final limit switch.
Traditionally, these devices serve as the last line of protection to prevent an elevator from traveling beyond its safe range. In many conventional elevators, especially traction elevators, they are considered essential safety components.
However, in our hydraulic home lifts, we have gradually found that these switches are no longer necessary from a technical standpoint.
This decision is not made to reduce cost or simplify wiring. Instead, it comes from the mechanical characteristics of hydraulic systems and our fully customized lift design philosophy.
What Is the Lower Final Limit?
The lower final limit switch (Bottom Final Limit or Lower Limit) is designed to prevent the elevator car from descending too far and striking the pit floor.
In conventional elevators, if the car continues moving downward due to a control failure, the lower final limit interrupts the circuit and stops the elevator before impact occurs.
For our hydraulic home lifts, the situation is different.
During installation, the hydraulic cylinder is adjusted so that when it is completely retracted, the platform remains approximately 20–30 mm above the pit floor or the ground.
This means that:
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The cylinder reaches its fully closed position first.
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The platform still has a small safety clearance.
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The cabin can never physically touch the pit floor.
Even in the unlikely event of a control malfunction, the hydraulic cylinder itself acts as the physical travel stop.
Because the cabin cannot move any lower, a lower final limit switch becomes unnecessary.
What About the Upper Final Limit?
The upper final limit switch is traditionally the last safety device that prevents an elevator from traveling upward into the overhead space.
Most upper final limit switches use normally closed contacts and are designed to stop the elevator if all other control systems fail.
Again, hydraulic home lifts operate differently.
Every lift we manufacture is fully customized according to the customer's required travel height.
Before production, we calculate:
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Required travel distance
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Cylinder stroke length
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Platform height
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Top clearance
The hydraulic cylinder is then manufactured with a stroke length that ensures the platform cannot travel beyond the designed maximum position.
Even if the cylinder extends completely, the cabin still remains within the safe travel zone and cannot strike the top of the shaft.
In other words, the mechanical stroke limitation of the cylinder itself prevents overtravel.
Mechanical Limits vs. Electrical Limits
Traditional elevators often rely heavily on electrical limit switches.
Our hydraulic home lifts rely primarily on mechanical travel limitation.
The maximum downward position is determined by the fully retracted cylinder.
The maximum upward position is determined by the cylinder stroke length.
Because both travel limits are physically defined by the hydraulic cylinder itself, additional electrical final limits become less critical.
This approach reduces:
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Additional wiring
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Extra sensors
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Installation adjustments
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Potential switch failures
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Maintenance requirements
At the same time, it simplifies the entire control system.
Why We Still Keep the Upper Limit Input
Although the upper final limit is no longer required from a mechanical perspective, our current control cabinets still include an upper limit input.
In many installations, we continue to install an upper limit switch as an additional layer of redundancy.
The PLC also monitors this signal.
This provides:
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Additional protection
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Easier troubleshooting
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Familiarity for installers
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Compliance flexibility for different markets
In other words, the upper limit currently serves as an extra safeguard rather than the primary safety device.
Future Considerations
As our hydraulic home lift designs continue to evolve, we may eventually remove the upper final limit entirely from the control system.
The combination of:
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Correct cylinder stroke calculation
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Mechanical travel limitation
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PLC monitoring
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Customized engineering
already provides a highly predictable and controlled travel range.
For low-speed hydraulic home lifts, safety does not necessarily come from adding more switches.
Sometimes, the safest design is one that eliminates unnecessary components and relies on simple, reliable mechanical principles.
Conclusion
Upper and lower final limit switches have long been considered standard elevator components.
However, in customized hydraulic home lifts, the hydraulic cylinder itself defines both ends of travel.
A fully retracted cylinder prevents contact with the pit floor.
A correctly calculated cylinder stroke prevents the cabin from reaching the top of the shaft.
As a result, the traditional upper and lower final limit switches become optional rather than essential.
Good engineering is not about adding more components.
It is about understanding which components are truly necessary.
If you are considering a 2-floor hydraulic home lift for your property, our team can walk you through the full engineering specification and safety design.
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