FAQs

A screw drive is a mechanical device that converts rotational motion into linear motion. It consists of a spindle and a nut with matching threads.

  1. Fully made of stainless steel
  2. Protection rating up to IP65
  3. Very compact due to hollow shaft motor

There are various types, including trapezoidal threads, ball screws, and acme threads. Each type has specific applications and characteristics.

No, the MINI and linear cylinders are complete systems and cannot be expanded with other motors.

In standard applications, linear drives can be operated with a speed of 250mm/s. Special applications have already been implemented with speeds exceeding 800mm/s.

Through a spring assembly, a defined force can be combined via the spring constant. When the spring assembly is compressed, a limit switch sends back the signal. Advantage: The limit switch can also be adjusted in position, allowing the customer to precisely adjust their force point.

Yes, linear drive systems with multiple chains connected together are common.

Yes, depending on the proximity to the product, the chain can also be completely made of stainless steel.

A spindle lifting drive is a combination of a spindle (screw) and a nut (worm gear or traveling nut) that converts rotational motion into linear motion through a worm gear drive.

MINI 0 (1,000 N), MINI 01 (1,600 N), MINI 1 (3,500 N), MINI 2 (14,000 N), MINI 3 (26,000 N)

Basic Version: The spindle itself performs the axial movement.

Traveling Nut Version: The spindle remains stationary in space but rotates. The nut then moves up and down on the spindle.

  1. Cubic & Classic: primarily external differences. A matter of personal preference regarding which one is preferred. Performance data is nearly identical.
  2. HMC: Standard up to 3000 rpm input speed, with oil filling and cooling fins - explicitly higher dynamic load capacity.
  3. KH: explicitly high dynamic capability, but load capacity decreases to a maximum of 90 kN.

The chain of the Linear Chain consists of links that rest on the shoulders and pins of the succeeding link. The chain of the Tower Chain is constructed with U-shaped chain links, providing greater stability and enabling unguided strokes of over 4m.

  1. Standard gearboxes with standard trapezoidal threads achieve efficiencies between 25-35%.
  2. Increasing the pitch makes the thread slip more easily, thus increasing efficiency.
  3. The combination with a ball screw can also achieve an efficiency of up to 50%.
  4. Best combination: bevel gear lifting drives with ball screws, which achieve over 80%.

For continuous monitoring, rotary encoders can be mounted on the motor or the worm shaft.

If only the end positions are relevant, limit switches can be used to query the desired end positions.

In hydraulic cylinders, we also often use potentiometers, which then return a certain resistance value that can be read out by the controller.

High-performance screw jacks are designed for demanding applications, providing high durability, precision, and efficiency in industrial environments.

They enable heavy loads, high speeds, and precise positioning. The robust construction ensures long life under extreme conditions.

These gears are used in automation, mechanical engineering, robotics, and other industrial sectors where high performance and reliability are required.

A high-speed screw jack is a mechanical device that enables fast and precise linear motion. It is often used in applications with short strokes and high speeds.

High-speed actuators are renowned for their rapid speed and ability to perform quick linear movements with short strokes, making them ideal for specific industrial applications.

They are utilized in areas such as automation technology, packaging industry, and production lines where fast and precise movements are necessary.

Use high-quality lubricants such as synthetic oil or grease with the recommended NLGI grades for maximum performance and longevity.

Since the chain undergoes radial movement due to the polygon effect, the guide plates are extended, and minimal play is allowed. This helps mitigate this effect.

No, within the buckling range, linear chains can also be used without guidance.

We always recommend using our standard link to connect your load. Utilize all the holes to ensure proper loading of the chain. Dimensions for the front link can be found here: General Catalog

You can choose between 24V, 230V, and 400V.

An electric cylinder is an electromechanical actuator that operates linearly and is powered by electrical energy to generate motion.

An electric cylinder converts electrical energy into linear motion. This is achieved through a motor driving a spindle, which in turn moves a load.

Electric cylinders offer precise positioning, easy control, high efficiency, low maintenance requirements, and a wide range of applications.

Features include high load capacity, precise positioning, robust construction, efficient energy conversion, and a variety of configuration options.

Electric cylinders are used in various industries, from industrial automation systems to medical and laboratory equipment, as well as in furniture and vehicles.

The IP66 classification indicates that the actuator is dust-tight and protected against strong jets of water. Ideal for applications requiring robust protection.

Actuators with IP66 are suitable for harsh environments such as industrial settings, outdoor use, or applications requiring water cleaning.

The IP66 protection class significantly reduces the ingress of dust and water, minimizing maintenance requirements. However, regular inspection is advisable.

Higher efficiency, higher speeds, precise theoretical calculation of service life

6 m/min

The maximum speed of trapezoidal screw drives is limited by the sliding velocity. If this is too high, the lubricating film tears off.

Both terms describe the ability of a spindle not to "slip" on its own when at a standstill.

Static self-locking refers to a thread angle between 2.4°-4.5°. In standstill, the spindle does not slip on its own, but it might not come to a stop on its own from motion. Dynamic self-locking occurs when there is an additional braking action from the dynamics. The thread angle is then smaller than 2.4°.

A rotation prevention is always necessary. Due to the sliding friction in the thread, the applied load would simply rotate along with it, and there would be no relative motion (linear motion).

The higher the axial force on the thread, the higher the frictional force, as Fr = FN * µ.

Self-locking refers to the "non-slip" behavior of spindle-nut systems without external force. The degree of self-locking is influenced by the material pairing, the pitch angle, and the lubrication.

The confusion sometimes arises because in both cases, there's an additional element at the back of the spindle.

  1. The spindle travel limiter is merely a ring on the thread that prevents the spindle from falling out.
  2. The rotation prevention additionally prevents the spindle from twisting.

Customer side: The customer bears the load, preventing it from twisting. If the spindle is then attached to the load, it also cannot twist.

Gear side (product itself has a prevention rotation): We either use a groove running completely through the spindle with a corresponding key as a counterpart. Alternatively, a square block can be screwed onto the back of the spindle, and the protective tube is designed as a square tube.

The specification '20% duty cycle per hour' is always associated with a certain power consumption at the gear unit. Therefore, if the permissible power value is not exceeded, less heat is generated, and the gear unit requires less time to cool down. This allows achieving more than 20% duty cycle.

Yes, screw jacks can be manufactured entirely in stainless steel and equipped with food-grade grease approved according to H1 standards.

The housing is made of aluminum die-casting or gray cast iron, the spindle, protective tube, and worm shaft are made of steel, while the worm wheel or travelling nut are made of a bronze alloy. Additionally, there are many variants.

Yes, with motor adaptors, motors or geared motors can be flexibly attached. You decide whether you want to provide the motor yourself or if GROB takes care of it.

Yes. A lifting gear unit can be operated with any rotary drive, whether electric, mechanical, or manual.

When under compression, typically buckling is the limiting factor. Under tension, it's either the availability of raw material (rods commonly available up to 6m) or the critical bending speed (in the case of the travelling nut version). For larger strokes, the spindle can also be made in multiple parts.

In applications with high safety requirements, two independently acting holding mechanisms may be required. This could be dynamic self-locking + motor brake or, alternatively, an independently switchable dual brake on the three-phase motor.

Yes. Common voltage types are 24 VDC / 230 VAC / 400 VAC. Additional voltages in both direct and alternating current ranges are available upon request.

A three-phase motor rotates depending on the mains frequency. The higher the frequency, the faster the motor rotates. Rated speeds at 50 Hz are as follows: for 2-pole motors, 3000 rpm; for 4-pole, 1500 rpm; for 6-pole, 1000 rpm; for 8-pole, 750 rpm.

Lubricating grease of NLGI grade 1 or 2, suitable for heavily loaded sliding and rolling bearings. Compatibility with the existing lubricant must be ensured. It's crucial whether the grease is mineral or synthetic-based.

It depends on the operating cycle and conditions. Typically, every 500 double strokes.

The lubricant quantity depends on the size and type of the gear unit. You can find specific data in our general catalog. Here's an example for our cubic screw jacks: General Catalog 2023 (grob-antriebstechnik.de)

0 - 6000 mm in the standard range. Lengths over 6 m are also possible for special applications, but then with a multi-part spindle. Gradations can be made in the millimeter range.

Grease lubrication in the gearbox: up to 1500 rpm; >1500 rpm to 3000 rpm flow grease or oil lubrication.

You can install mechanical, magnetic, or inductive limit switch solutions. Preparation for custom sensors is also possible. Please note that it's not possible to implement end position detection on travelling nut version screw jacks.

For detailed information, refer to the beginning of each screw jack chapter in our catalog. Here's an example for cubic screw jacks: General Catalog 2023 (grob-antriebstechnik.de)

For grease-lubricated screw jacks, the mounting position can be freely chosen. For oil-lubricated screw jacks, the orientation of the ventilation must be considered.

The manufacturer's rated load capacity should not be exceeded. However, screw jacks typically have safety factors ranging from 1.5 to 2.5 times the rated load.

Temporarily possible, however, this results in a significantly reduced lifespan.

Yes, for screw jacks with ball or roller screw mechanisms, a lifespan can be calculated. However, for trapezoidal screw mechanisms, lifespan calculation is not possible. More information on the calculations can be found here.

The required power depends on the load and lifting speed. A 30% reserve to the required power is recommended for the drive. The screw jack should be operated within the maximum specified parameters, which depend on the version and size. You can find exemplary power limits for cubic screw jacks here: General Catalog 2023 (grob-antriebstechnik.de)

The safety margin can be increased or reduced. If reduced, it's important to ensure that block drive is always prevented during operation of the system.

A block drive describes the execution of the lift against a fixed stop. In this process, the lifting element is 'blocked' by the fixed counterpart.

The driving element, usually a three-phase motor, doesn't stop automatically but needs a signal for shutdown. This signal can be generated through limit switches, encoders, potentiometers, or other displacement-monitoring components.

Mechanical drives are very sensitive to movement against fixed stops. Depending on the force of the motor, a block drive typically results in damage to the spindle-nut system.

Ball screw spindles make sense when:

  1. The power consumption is too high in combination with trapezoidal screw spindles
  2. A higher lifting speed is desired
  3. A higher precision is desired

The axial play of a trapezoidal screw spindle typically ranges from 0.1 to 0.3 mm. When the axial play reaches 1/4 of the trapezoidal profile, replacement of the trapezoidal screw nut is recommended.

Although lateral forces significantly reduce the lifespan of screw jacks, there are certain limits within which lateral forces can be absorbed. You can find relevant information here: General Catalog 2023 (grob-antriebstechnik.de)

The standing spindle creates relative motion through the rotating worm wheel, while the rotating spindle generates relative motion for the travelling nut. The advantages and disadvantages depend on the space constraints of your lifting system.

Yes, each size (regardless of the screw jack type) offers 2x reduction stages (-> Normal and Slow). The exception is bevel gear screw jacks. Here, gear ratios of 1:1, 2:1, and 3:1 are possible.

Spindle extension defines a dimension that provides a certain extra length compared to the standard when in the retracted state. For example: You only need an effective stroke of 100mm, but there's a distance of 400mm to cover between the start of the stroke and the gearbox. Then we extend the spindle by 400mm, so when fully extended, you reach a total of 500mm.

For the spindle end, the standard range offers options including threaded end, articulated head, ball joint head, flange plate, bearing flange plate, and pin. You can find corresponding dimensions in the General Catalog 2023 (grob-antriebstechnik.de)

Yes, appropriate protection can be achieved through painting or the use of stainless materials.

  1. Electronic bridge: If each lifting element of the system is driven by a motor, electronic synchronization can be achieved through encoders.
  2. Mechanical linkage: More cost-effective and fail-safe are cardan shafts and bevel gearboxes, which can connect all lifting elements of a system together.

Yes, the functions of 'lifting' and 'moving' can be performed by any mechanical lifting element.

This version uses an additional tube to protect the spindle, which sits on the travelling nut. The piston tube version thus describes a lifting cylinder that has been modified based on a sscrew jack.

The following points necessitate an oil version:

  1. Use in explosive atmospheres with gas. A mandatory ATEX questionnaire is required.
  2. Input speed at the worm shaft ranging from 1500 rpm to 3000 rpm.

In the case of the travelling nut version, only the nut connection dimensions change. In the basic version with the ball screw spindle, it may occur that the bearing cover is raised to accommodate the ball screw nut in the gearbox.

Yes, the use of stainless steel materials is a common practice for environments with aggressive media.

In standard operation, the SFM runs load-free with the main nut. If the main nut fails, the SFM takes over the load. A stroke can then be performed to shut down the system. Additionally, the SFM is also used as a reference nut for wear measurement.

The spindle can be protected by folding bellows or spiral protective sleeves.

It prevents rotation of the spindle. If a translational spindle were to rotate, linear motion would no longer be possible.

A travel limiter (AS) prevents the spindle from accidentally falling out in the basic version. It is not intended as a mechanical end stop.

No, swiveling movements are not possible with the linear chain.

No, you should provide a brake on the motor.

65% with chain magazine, 80% with free chain.

The polygon effect occurs when a chain is positively driven by a sprocket. In this case, the chain cannot run perfectly circularly on and off the sprocket, causing deviations in the path of the traction medium. The speed of the chain then fluctuates periodically around a mean speed, which can manifest as vibrations in the chain.

No, the load MUST always be guided.

There is no calculation basis for this. The buckling length has been determined through tests. You can find a corresponding diagram for horizontal applications here: General Catalog 2023 (grob-antriebstechnik.de). For vertical applications, please contact us.

No, a linear chain can never take over the guiding itself. The load must be guided.

  1. Lubrication system: attached lubrication brushes extend the lifespan.
  2. Chain magazine: the chain can be rolled up behind the housing.
  3. Reduction gear: especially useful in lifting systems to reduce torque through gears.
  4. Force sensor: for measuring axial load and protection against overload.

Here is no calculation basis for this. Tests have shown that for standard chains, 250,000 cycles, and for hardened chains, 1,000,000 cycles represent realistic values.

  1. When under pressure load: depending on the control, 100% repeatability can be achieved.
  2. Under changing loads: the control system must consider the backlash at the sprocket and manufacturing tolerances in the chain links.

As standard, GROB chains are galvanized. For environments with aggressive media, stainless steel chains can be used.

  1. Standard: 180°C
  2. High-temperature continuous: 550°C
  3. High-temperature short-term (under 2 minutes): 1050°C
  1. The load must be guided
  2. The push chain size must be chosen correctly
  3. It should be driven over a ramp
  1. The load must always be guided
  2. Acceleration should be controlled via a ramp
  3. The chain cannot perform a swiveling movement
  4. The permissible buckling length must not be exceeded

Depending on the size, the driving speed is usually below 50 rpm.

Yes, hardened chain links achieve a lifespan four times longer.

  1. A chain magazine winds the chain in multiple circular paths. Advantage: greater space saving.
  2. A chain cover protects the chain attached to the housing. Due to the attachment, the chain aligns itself and thus halves the stroke length. Advantage: more cost-effective.

Yes, the chain can be stored perpendicular to the lifting movement, such as 90°, or even 180° (parallel) to the lifting movement, as in the case of tool tables. The lift then operates on the table, while the storage runs parallel underneath it.

The T-guide was developed when space for the standard rail above the sliding surface was lacking. In one application example, the customer needed to maneuver with a forklift. The T-guide rail was then embedded in the floor, allowing the vehicles to continue maneuvering undisturbed.

The different installation positions do not affect the usability of linear chains (e.g., through oil sight glasses or similar). By simply changing the mounting side of the mounting brackets, the mounting sides can be adjusted as needed.

Yes, screw jacks and MINI cylinders can be used within certain limits for ATEX zones as well.

Key factors include load, speed, precision, and environmental conditions. If load is more important to you, a trapezoidal screw might be suitable. If speed is crucial, a ball screw would be more advantageous. The choice depends on the specific requirements of your application.

Screw drives require regular lubrication to minimize wear. The type of lubricant and the intervals depend on the operating conditions.

Overheating, unusual noises, or a noticeable decrease in performance can be signs of insufficient lubrication. Pay attention to these symptoms for timely maintenance.

Maintenance involves regular lubrication according to manufacturer specifications. Inspections for wear and timely re-lubrication are crucial for longevity.

Lubrication should be performed every 3 to 6 months, or after 500 double strokes, depending on the frequency of use and the environment.

Increasing the ambient temperature does affect the duty cycle. A higher ambient temperature necessitates a longer cool-down period.

Inspect moving parts for signs of wear and increasing play. If wear is detected, consideration should be given to inspection or replacement.

Yes, the maintenance and operating manual provides valuable guidance on the procedure. You can find the documentation here.

Is the motor correctly wired and the brake releasing? Do you have sufficient lubricant on the spindle? Are the drives installed without tension? If so, you've already eliminated the most common sources of malfunction. If the issue persists, please call us at +49 7261/9263-0.

The environment can affect maintenance intervals. High levels of dust or humidity may require shorter maintenance intervals. Regularly check the environmental conditions and adjust the maintenance schedules accordingly.

Check the power supply, brake wiring, and the condition of the control unit. If necessary, contact our customer support. Also, ensure proper wiring of the limit switch. Most blockages occur during setup operations.

Check for dirt or worn-out parts. Thorough cleaning and, if necessary, replacement of damaged components may solve the problem. If the linear chain is noisy after acquisition, system tensions could be responsible.

Check the connection to the control system and the programming. Ensure all safety precautions are accounted for.

Check the power supply. For 24V DC drives, fluctuating loads can also cause varying speeds. Additionally, ensure that potentiometers, encoders, and brakes are correctly controlled.

Regular maintenance, including lubrication and checking for wear, helps extend the lifespan of your high-performance screw jack.

A thorough familiarization with the operating manual is advisable. However, in case of uncertainty or complex maintenance tasks, specialized personnel should be consulted. You can reach us anytime at +49 7261/9263-0.

For compatibility, it's simply a matter of checking the base of the lubricant (mineral or synthetic) and ensuring the NLGI grade is the same. Divinol Lithogrease 1500 is commonly used as the standard.

No, the standard grease can be replaced by other greases with the same properties. If you would like to know whether your grease is compatible with our standard grease, you can send us the data sheet of your preferred grease, and we will check it for you.

No, a fixed bearing is fundamental in any drive system. Without a fixed bearing, reliable axial movement cannot be performed.

Yes, for short spindles or low speeds, the spindle is sufficiently dimensionally stable without additional radial bearings at the spindle end.

Pillow block bearings are used in lift systems with mechanical coupling (i.e., connecting shafts). The bearings shorten the free length of the connecting shafts, thereby preventing oscillation at high speeds.

GROB Antriebstechnik is characterized by a large inventory of bearings, enabling fast and reliable delivery. Moreover, the family-owned company provides excellent customer consultation and customized solutions.

The extensive inventory allows GROB to have a wide range of products constantly available. This means prompt processing and delivery for customers.

Our dedicated team of experts is here to assist you with expertise and experience. We listen attentively, understand your needs, and provide tailored recommendations for optimal solutions.

We understand that each customer has unique requirements. That's why we offer tailored solutions that are precisely aligned with individual needs and applications.

Thanks to our large inventory, we can efficiently process orders and ship them quickly. This allows for timely delivery that meets our customers' needs.

Self-locking is achieved with a pitch angle below 4.5 degrees.

Both types of threads have their merits. Generally, ball screws are used for fast and precise linear movements. Trapezoidal screws are employed when the focus is solely on adjustment or if the operation is more rugged.

When transporting people, DIN EN ISO 17206 applies. This standard for event technology defines the required safety measures, safety devices, and system-relevant shutdowns.

You have several options for achieving this:

  1. Modifying the gear ratio
  2. Modifying the spindle pitch
  3. Adjusting the motor speed

All of these measures are available in many standard configurations from us

Our CAD models are available online through the CAD configurator at CAD Configurator - GROB Antriebstechnik GmbH (grob-antriebstechnik.de). If your product is a custom specification, you will receive a model within 3 working days from the quotation stage.

In our standard range, we adhere to military standards: -20°C to +60°C.

A classic case for troubleshooting. Give us a call, we're happy to assist you. +49 7261/9263-0

A linear actuator converts rotational motion into linear motion. It is powered by electric motors. However, linear movements can also be achieved through hydraulic or pneumatic actuators. Electric linear actuators are used for more precise movements.

Typically, it's an electric linear drive. It consists of three main components: spindle, motor, and gearbox. When a signal is received, the motor converts electrical energy into mechanical energy, moving the gears of the gearbox. These rotate the spindle, causing the spindle nut to move outward or inward.

Linear actuators are ubiquitous: in homes, offices, hospitals, factories, agricultural settings, and many other places. In hospitals and medical centers, you'll find linear actuators used to adjust patient tables, hospital beds, or operating tables. Other applications are in industry, agriculture, construction, and industrial automation.

There are mechanical, electromechanical, direct electric linear actuators (linear motors), as well as hydraulic and pneumatic linear actuators. We utilize electromechanical actuators in our drive solutions.

Electric linear drives use electrical energy for motion, whereas hydraulic and pneumatic drives use fluids or gases. Electric drives are more precise and efficient.

The determining factor for motor size is power, which results from the product of speed and torque. For more information on this topic, please refer to our Learning Center.