ZH90 Lift Axis with Double Stroke: Long Lifting Travel with Little Headroom
A lift axis needs to travel far down, but there is hardly any space above the steel structure. This is exactly the problem solved by the ZH90 lift axis with double stroke. Instead of one long lift axis, two separate lifting elements work independently of each other and together reach the lifting travel the customer needs. The customer's own handling fixture is mounted on a flange, the load of up to 400 kg is balanced and can be guided by hand.
Zeilhofer Handhabungstechnik from Holzkirchen, Germany, developed this lift axis for handling car parts. This article explains why a single-stage lift axis would not have fit here, how the double stroke works and what matters when designing it. The detailed workflow at the station is shown in the article ZH90 lift axis in a rail system.
Key points at a glance
From the steel structure, the customer has to travel a long way down, but above the steel structure there is no room for a continuous long lift axis.
The ZH90 lift axis with double stroke splits the lifting travel between two separate lifting elements that work independently of each other.
Together, both elements reach the required lifting travel with less overall height above.
The customer attaches its own handling fixture via a flange and handles loads of up to 400 kg in balance.
After the work is done, the lift axis returns to its parking position by pull cord.
What is a lift axis with double stroke?
A lift axis guides loads rigidly and without swinging along the vertical Z axis. In a classic single-stage lift axis, one single lifting element covers the entire lifting travel. In a lift axis with double stroke, two separate lifting elements share this task. Each element works on its own, together they provide the full lifting travel. How lift axes generally differ from lift columns and manipulators is explained in the article Lift column, lift axis or manipulator.
The double stroke is not a separate product line but a version of the ZH90 lift axis for a specific installation situation: a lot of lifting travel downwards, little space upwards.
The installation space problem: why a single-stage lift axis would not have fit
A lift axis hangs from a trolley that runs on a rail mounted to the steel structure. In a single-stage lift axis, the lifting element is at least as long as the lifting travel. When the load moves up, the lifting element passes up through the trolley and protrudes above the suspension. The longer the lifting travel, the more space the lift axis needs above the steel structure.
In this application, that was exactly the bottleneck:
Long way down: From the steel structure, the fixture has to travel a certain distance down to pick up and set down the component.
No space above: Above the steel structure there is not enough room for the full length of a single-stage lift axis.
Fixed conditions: The steel structure and the hall already existed, rebuilding the ceiling or the supporting structure was not an option.
A larger lifting height alone is not a problem for the ZH90 lift axis, as shown for example in the article 2 metre lifting height. What mattered here was the combination of long lifting travel and limited overall height.
How the double stroke works
The double stroke solves the installation space problem by splitting the lifting travel between two shorter lifting elements. Neither of them has to cover the entire distance alone. As a result, in its top position the lift axis protrudes less far above the steel structure than a single-stage axis with the same total stroke.
Two separate elements, one shared lifting travel
Separate design: Two independent lifting elements instead of one continuous long lift axis.
Independent operation: Both elements work independently of each other.
Shared lifting travel: Together they reach the lifting travel the customer needs for picking up and setting down.
Same operation: For the operator it is still one lift axis. The load is balanced, guided by hand and sent back to the parking position by pull cord.
Distinction: double stroke, synchronous extension and double lift axis
Zeilhofer offers several solutions with two elements that are easily confused. With the synchronous extension, the guide elements of one lift axis are mechanically coupled and extend together. With the double lift axis for sliding steps, two synchronised lift axes side by side carry a shared fixture. The double stroke, by contrast, is a single lift axis whose lifting travel is split between two independently working lifting elements.
Balance and guidance
In this application the load is balanced. The operator guides the fixture with little hand force and positions it rigidly and without swinging on the component. How this principle works is explained in the article on swing-free handling.
Current situation: more conversions of existing plants
Many manufacturers and suppliers are modernising existing plants instead of building new ones. Such brownfield projects save investment but have to work with existing buildings, layouts and equipment, as a report by Automotive Manufacturing Solutions describes using the example of a car plant. For the modernisation of existing battery factories alone, VDMA and Porsche Consulting see a market potential of around 135 billion euros according to ingenieur.de.
For lifting aids this means: the hall sets the dimensions, not the other way round. Low ceilings, existing steel structures and dense building services limit the installation space. A lift axis that adapts to the existing building saves alterations to the building.
Regardless of installation space, the obligation to design workplaces ergonomically remains. From 20 January 2027, the EU Machinery Regulation (EU) 2023/1230 applies. What this means is summarised in the article EU Machinery Regulation 2027: ergonomics duties. A compact overview is provided by our free whitepaper Hebehilfen 2027 (German).
The starting point in this application
The customer handles car parts on an assembly line. The lift axes hang from an existing steel structure and are meant to bring the customer's handling fixture to the component.
The installation situation resulted in the following requirements:
Long lifting travel from the steel structure down to the pick-up and set-down position.
Limited installation space above the steel structure, too little for a single-stage lift axis.
Loads of up to 400 kg including the customer's own fixture.
Connection of the customer fixture via a flange.
Simple operation: guide in balance, return to the parking position by pull cord.
Single-stage lift axis and double stroke compared
Feature | Single-stage lift axis | Lift axis with double stroke |
|---|---|---|
Design | One lifting element for the entire lifting travel | Two separate, independently working lifting elements |
Space required above the suspension | Grows with the lifting travel | Less, because the lifting travel is split |
Typical use | Sufficient space above | Little space above the steel structure or ceiling |
Operation for the operator | Balance, guided by hand | Balance, guided by hand |
Fixture | Via flange or as custom design | Via flange or as custom design |
Alternatives when overall height is limited
When there is little space above the station, other lifting aids can also be considered. They differ mainly in how the load is guided.
Chain hoist or crane
A chain hoist or crane needs little overall height, but the load swings on the hook. Rigid guidance for precisely positioning a fixture on the component is missing. How big the difference is in cycle time is shown in the comparison overhead crane versus ZH90 lift axis.
Cable manipulator
A cable manipulator is also low in height but guides the load on a cable. That is ideal for light parts, less so for heavy fixtures that need an exact position.
Articulated jib manipulator and Flex-Arm
An articulated jib manipulator guides rigidly and needs no height above the station, but stands on a column on the floor. The ZH90 Flex-Arm lift axis combines manipulator and lift axis. Which Z axis solution fits is shown in the comparison lift axis or manipulator.
Lift axis with double stroke
It combines the rigid, swing-free guidance of a lift axis with an overall height that fits into the available space. The floor stays clear, the ceiling does not need to be modified.
Safety, inspection and operation
With a double stroke, the same requirements for safety and documentation apply to the ZH90 lift axis:
CE conformity: Designed in accordance with the Machinery Directive 2006/42/EC, EN ISO 12100 and DIN EN 14238, with risk assessment, declaration of conformity and operating instructions.
Safe parking position: After the work, the lift axis returns to the top by pull cord.
Swing-free guidance: The load is guided rigidly, which protects component, fixture and operator.
Statutory inspection: The procedure and intervals are explained in the guide UVV inspection for lifting aids.
Service: Maintenance, spare parts and technical support are provided by our service team.
Checklist: do I need a lift axis with double stroke?
These points quickly show whether a single-stage lift axis is enough or a double stroke is needed:
Suspension height: How high is the underside of the rail or steel structure?
Lifting travel downwards: How far down does the fixture have to travel for pick-up and set-down?
Space above: How much room is there between the suspension and the ceiling, crane runway or building services?
Interfering contours: Are there beams, pipes or lamps in the area above the lift axis?
Load: Combined weight of component and fixture.
Fixture: Your own fixture via flange or designed by Zeilhofer?
Workflow: Pick-up, set-down and parking position within the cycle.
Operation: Pull cord, push buttons or controls on the handle.
Steel structure: Load capacity and connection options for the rail.
Inspection and maintenance concept: Statutory inspection, maintenance intervals, spare parts.
The costs involved are explained in the guide What does a manipulator cost? How quickly a lifting aid pays for itself is shown in Calculating the payback of a lifting aid. As an alternative to buying, you can finance via leasing or hire purchase.
How a project with Zeilhofer works
From the enquiry to the running system, Zeilhofer supports the project from a single source. Since 1999, the company has delivered over 2,500 systems in 18 industries to customers in over 50 countries.
On-site meeting: Survey of steel structure, space above, lifting travel and workflow, more on this under customer-specific consulting.
Concept: Decision between single-stage lift axis and double stroke, design of the interface to the fixture.
Design and manufacturing: Engineering and manufacturing in Holzkirchen, Germany, according to ISO 9001.
Pre-acceptance: Test at the plant in Holzkirchen or digitally via video.
Installation and commissioning: By Zeilhofer or by the customer, including documentation.
Service: Statutory inspection, maintenance and spare parts over the entire service life.
In the automotive industry, confidentiality matters. Zeilhofer is certified to ISO 9001 and TISAX Level 2 with prototype protection. What this means is explained in the article What is TISAX?
Glossary
Lift axis: Lifting aid that guides loads rigidly and without swinging along the vertical axis. More terms in the handling technology glossary.
Double stroke: Version of a lift axis in which two separate lifting elements work independently and together provide the lifting travel.
Lifting travel: Distance the load covers between the top and bottom position.
Overall height: Space the lift axis needs above its suspension.
Steel structure: Supporting structure above the station from which the rail and lift axis hang.
Interfering contour: Obstacle in the movement space, such as beams, pipes or lamps.
Synchronous extension: Zeilhofer solution in which the guide elements of a lift axis are mechanically coupled and extend together.
Flange: Mechanical interface to which the fixture is bolted.
Balance: State in which the control compensates for the weight of the load.
Brownfield: Modernisation or conversion of an existing plant instead of a new build.
Frequently asked questions
What is a lift axis with double stroke?
A lift axis with double stroke splits the required lifting travel between two separate lifting elements that work independently of each other. Together they reach the full lifting travel, but each individual element is shorter than a single-stage lift axis with the same stroke. As a result, the lift axis needs less space above.
When do you need a lift axis with double stroke?
Whenever the load has to travel far down from a high suspension, such as a steel structure or ceiling rail, but there is not enough space above the suspension for a continuous long lift axis. This is typical in existing halls with low ceilings or dense building services.
How does the double stroke differ from the synchronous extension?
With Zeilhofer's synchronous extension, the guide elements of the lift axis are mechanically coupled and extend together. With the double stroke, two separate lifting elements work independently of each other. Which solution fits depends on lifting travel, installation space and workflow.
How much can the ZH90 lift axis with double stroke carry?
In this application, the customer picks up and handles up to 400 kg. The ZH90 lift axis is generally available for loads of up to 1,200 kg, and each system is designed for its load and lifting travel.
Can I attach my own fixture to the lift axis with double stroke?
Yes. In this application, the customer mounts its own handling fixture to the lift axis via a flange. On request, Zeilhofer also designs the fixture.
Does the double stroke change how it is operated?
Operation remains simple for the operator. In this application, the load is balanced and can be guided by hand. After the work, the operator sends the lift axis back to its parking position by pull cord.
Can a lift axis with double stroke be retrofitted in an existing hall?
That is often exactly what it is for. What matters is the height between suspension and ceiling, the required lifting travel downwards, the load capacity of the steel structure and possible interfering contours. Zeilhofer clarifies these points during an on-site meeting.
Is a lifting aid mandatory from 2027?
There is no general obligation to use a specific lifting aid. However, employers must assess and reduce risks when lifting. In addition, from 20 January 2027 the EU Machinery Regulation (EU) 2023/1230 applies to machinery placed on the market.
Your application: long lifting travel, little space above
Your hall offers little space above, but the load has to travel far down? We check on site whether a single-stage lift axis is enough or a double stroke is the better solution. Call us on +49 (0)8024 / 46330-60 or send us your enquiry.
More practical examples from vehicle production can be found in the guide Lifting aids for automotive final assembly and under Handling technology for the automotive industry. Further applications of the ZH90 lift axis: lift axis in a rail system, car seat assembly, cockpit modules and custom grippers and fixtures. An overview of all 18 industries is provided on the page Applications.
