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SERVOMECH
Acme Screw Jacks

Acme Screw Jacks

Product catalog summary

General Overview
Screw jacks convert rotary motion into linear movement, suitable for both vertical and horizontal applications. They can be used individually or in synchronized systems. SERVOMECH offers two models: travelling screw (Model A) and travelling nut (Model B), available in MA and SJ series with varying performance levels.

Manufacturing Features
SERVOMECH screw jacks are manufactured using high technology and CNC machinery, adhering to ISO 9001:2008 standards. They feature high-efficiency worm gears and robust housing materials such as aluminum alloy, cast iron, and steel.

Materials and Components
Acme screws are made from steel C 43, with options for rolled or whirled threads. Bronze nuts and ball screws are also available, using materials like steel 42 CrMo 4 and bronze EN 1982.

Acme Screw Jacks
The MA Series offers high efficiency with oil lubrication, while the SJ Series provides standard performance with grease lubrication. Both series have multiple sizes and configurations, including 1-start and 2-start acme screws.

Ball Screw Jacks
The MA BS Series is designed for high efficiency and continuous operation, while the SJ BS Series offers standard performance. Both series have various input versions and are suitable for different load capacities.

Models and Versions
Both MA and SJ series are available in two models, with options for different input configurations. Accessories include protective tubes, safety nuts, and wear indicators.

Installation and Maintenance
Guidelines for installation, maintenance, and lubrication are provided to ensure optimal performance and longevity of the screw jacks.

Screw Jack Specifications and Selection Criteria

1. Screw Jack Versions:
- Vers.5: Version 1 with bell housing and coupling for IEC motor.
- Vers.6: Version 2 with bell housing and coupling for IEC motor.

2. Mounting Positions:
- Models A and B can be mounted in various positions: Upward (U), Downward (D), Horizontal (H), Left-Hand (LH), and Right-Hand (RH).

3. Selection Criteria:
- Screw jacks convert rotary to linear motion with energy loss depending on screw-nut efficiency.
- Duty cycle (Fu [%]) of the application must be compared to the screw jack's permissible duty cycle (Fi [%]).
- Environmental temperature affects the permissible duty cycle, requiring adjustments using a correction factor.

4. Screw Jack Models:
- Model A: Travelling screw.
- Model B: Travelling nut.

5. Series and Duty Cycles:
- MA Series: High efficiency, oil lubricated.
- SJ Series: Standard performance, grease lubricated.
- Duty cycles at 25°C: MA Series allows 40% over 10 min, 30% over 1 hour; SJ Series allows 30% over 10 min, 20% over 1 hour.

6. Lifting Systems:
- Consider platform dimensions, stroke length, total load, and system configuration.
- Evaluate static safety, norms, noise, and vibrations.
- Use auxiliary safety nuts for hanging loads and ensure self-locking conditions.

7. Self-Locking Conditions:
- Static self-locking occurs when a non-working screw jack does not move under load.
- Dynamic self-locking occurs when a working screw jack stops upon power interruption.
- Efficiency values determine self-locking and back-driving conditions.

8. Acme Screw Buckling:
- Buckling resistance is crucial for push loads.
- Euler curves help determine the maximum push load for different screw configurations.

9. Critical Rotating Speed:
- For Model B, ensure the acme screw's rotating speed does not reach its critical speed.

Overview: The document provides detailed technical specifications and operational guidelines for acme screw jacks, focusing on the MA Series. It includes information on screw length, rotating speed, structural elements, and technical specifications for different models.

Specifications: The document outlines the specifications for acme screws, including thread types, lengths, and rotating speeds. For example, a screw jack SJ 150 with an acme screw Tr 60×12 can rotate at a maximum speed of 420 rpm, translating to a linear speed of 85 mm/s.

Procedures and Recommendations: It emphasizes the importance of considering static deflection in horizontal mounting and recommends using a screw supporting system to ensure alignment and concentricity. For supported acme screw ends, the document provides an example of a screw jack MA 50 with a maximum rotating speed of 550 rpm.

Structural Elements: The MA Series screw jacks are described with components such as acme screws in steel C 43, worm shafts, bronze wormwheels, thrust ball bearings, and gearboxes designed for heat dissipation and increased duty cycles.

Technical Specifications: Detailed specifications for various MA Series models (MA 5, MA 10, MA 25, MA 50, MA 80, MA 100, MA 200, MA 350) are provided, including load capacities, worm gear center distances, available ratios, stroke per input shaft revolution, starting and running efficiencies, starting torque, and permissible operating power.

Performance Tables: The document includes tables showing linear speed, torque, and power on the input shaft for different input speeds, ratios, and loads. It highlights operational restrictions due to thermal limits and advises contacting SERVOMECH Engineering for further evaluation.

Key Considerations: The document stresses the importance of evaluating thermal limits and duty cycles, especially when operating within restricted areas. It suggests selecting a larger screw jack size for better heat dissipation if necessary.

Stop Nut
Available for screw jacks with travelling screw (Mod. A) only, the stop nut prevents the acme screw from unscrewing out of the housing. It acts as a safety measure by allowing an additional 20 mm stroke at maximum extension. If the stop is reached accidentally, components should be checked for damage. Ordering code: SN.

Protective Tube
Also for Mod. A, the protective tube shields the acme screw from environmental damage and allows for additional options like limit switches. Made from aluminium or steel, it is ordered with code T.

Anti-Turn Device
For Mod. A, this device prevents the load from turning by using a steel key and a bronze washer. It is essential when the load may rotate or the application does not allow screw reaction. Ordering code: AR.

Trunnion Mount
Available for both Mod. A and Mod. B, the trunnion mount allows the screw jack to pivot. It requires specific mounting configurations depending on the model. Ordering codes vary based on the mounting side.

Bellows
Bellows protect the screw from contaminants and are available for both models. They affect the dimensions and are made from NYLON with PVC coating. Ordering code: B.

Safety Nut
For both models, the safety nut prevents uncontrolled load dropping if the working nut thread fails. It is positioned based on load direction and changes the overall dimensions. Ordering codes differ for push and pull loads.

Acme Thread Wear Level Check
This feature allows monitoring of thread wear to prevent critical failure. Wear is checked by measuring changes in specific dimensions or using an electric switch for alerts.

Wormwheel Rotation Detector
Available for both models, this detector verifies wormwheel rotation to ensure proper functioning. It uses a proximity switch activated by a machined crown of spaces.

Magnetic Stroke End Switches
For Mod. A and sizes 5, 10, or 25, these switches detect extreme positions using a magnetic field. They require an electric connection to prevent reactivation in the same direction. Ordering codes: FCM-NC and FCM-NO.

Inductive Proximity Stroke End Switches
For Mod. A only, these PNP inductive sensors detect extreme positions. They are not adjustable by default but can be customized. Ordering code: FCP.

Adjustable Backlash
Available for both models, this feature reduces axial backlash for precision. It involves adjusting the wormwheel or nut halves to eliminate play. Excessive reduction can affect efficiency. Ordering code: RMG.

Material Specifications: The screw jacks MA Series can be supplied with stainless steel acme screws and/or screw attachments for specific environmental conditions or food industry applications. Available stainless steels include AISI 303, AISI 304, and AISI 316.

Ordering Codes: Various ordering codes are provided for different configurations, such as TR inox for stainless steel acme screws and P inox for stainless steel flange ends.

IEC Motor Connection: The document lists compatibility with various IEC motor sizes and configurations, including B5 and B14 flange types, with specific models like MA 5, MA 10, MA 25, etc.

Screw Jacks MA Series: The MA Series is available in two models: Mod.A with a travelling screw and Mod.B with a travelling nut. Each model has specific configurations and options, such as input versions, mounting positions, and stroke lengths.

Options and Accessories: A wide range of options is available, including screw ends, bellows, trunnion mounts, bronze guides, adjustable backlash, stop nuts, protective tubes, and various end switches.

Technical Specifications: Detailed technical specifications are provided for the SJ Series screw jacks, including load capacities, available ratios, stroke per input shaft revolution, efficiencies, starting torque, and permissible operating power. The document also specifies materials used for gearboxes and the mass of screw jacks.

Spare Parts: Lists of spare parts for both Mod.A and Mod.B screw jacks are provided, including gearboxes, worm shafts, wormwheels, bearings, seals, and other components.

Structural Elements: Descriptions of structural elements for both Mod.A and Mod.B screw jacks are included, detailing components like acme screws, worm shafts, wormwheels, bearings, and lubrication systems.

Overview: The document provides detailed technical specifications and operational guidelines for the SJ Series screw jacks, focusing on their torque, power, and linear speed capabilities under various loads and input speeds. It includes tables for different models and sizes, highlighting the torque (T1), power (P1), and linear speed (v) at specified input speeds (n1) and load capacities (kN).

Specifications: The screw jacks are categorized by load capacity, ranging from 400 kN to 1000 kN, with corresponding torque and power values. The tables specify the operational parameters for different models, including SJ 400, SJ 600, SJ 800, and SJ 1000, under various load conditions and input speeds.

Operational Guidelines: The document emphasizes the importance of adhering to duty cycles, with a maximum of 30% over 10 minutes or 20% over an hour at 25°C. It warns against operating within red-shaded areas of the tables, which indicate thermal limits, suggesting a reduction in duty cycle or selection of a larger screw jack for effective heat dissipation.

Efficiency and Ratios: Efficiency tables are provided for different screw jack sizes, detailing the total efficiency at various input speeds and load conditions. The ratios (RV, RN, RL) are used to calculate intermediate values for torque, power, and speed through linear interpolation.

Design and Dimensions: The document includes detailed dimensions for each screw jack model, specifying measurements for components such as the acme screw, housing, and mounting options. It also outlines the available options like stop nuts, protective tubes, anti-turn devices, and trunnion mounts, with corresponding ordering codes.

Recommendations: For optimal performance, it is recommended to consult with SERVOMECH Engineering for selections within restricted operational areas. The document also advises on the use of protective and anti-turn devices to prevent damage and ensure proper operation.

Screw Jacks SJ Series Overview
This document provides detailed specifications and options for the Screw Jacks SJ Series, focusing on models with travelling screws (Mod. A) and travelling nuts (Mod. B). It includes information on various components, safety features, and customization options.

Specifications and Options

Bellows: Available for both models to protect screws from contaminants. Standard material is NYLON with PVC coating, with options for different materials and strokes (300 mm, 600 mm, 1000 mm).
Safety Nut: Acts as a backup to prevent load dropping if the working nut thread breaks. It is positioned based on load direction and alters the overall dimensions of the screw jack.
Thread Wear Control: Allows monitoring of thread wear to prevent critical failure. Wear level is checked by measuring the distance between the working nut and safety nut.
Wormwheel Rotation Detector: Available for Mod. A, it verifies wormwheel rotation to ensure proper functioning.
Magnetic and Inductive Proximity Stroke End Switches: These sensors help in stopping the screw jack at extreme positions and are available for Mod. A.
Material Options: Stainless steel components are available for specific environmental conditions or industries.

Ordering Codes and Customization
The document provides detailed ordering codes for various configurations, including motor specifications, mounting options, and additional features like anti-turn devices and limit switches.

Spare Parts
Detailed lists of spare parts for both Mod. A and Mod. B are provided, including gearboxes, worm shafts, bearings, and seals. It is recommended to refer to the product serial number for orders.

Installation and Maintenance of Screw Jacks

Transport and Handling: Screw jacks with mounted acme screws can be challenging to handle due to their size. Careful handling is recommended to avoid damage and ensure safety. Identify and use supporting points during transport.

Storage: Protect screw jacks from atmospheric agents and pollutants. For storage over six months, move input shafts periodically and lubricate unpainted parts to prevent oxidation.

Installation: Install screw jacks to handle axial loads only, avoiding lateral and radial loads. Ensure perpendicularity between the acme screw axis and the fixing plane. For synchronized lifting, align load supporting points and use high torsional stiffness shafts and couplings.

Commissioning and Use: Screw jacks come with specified lubricants, but the acme screw requires initial lubrication by the customer. Check input shaft rotation, stroke end switch positions, and mechanical drive connections before use. Do not exceed the allowed duty cycle to prevent overheating.

Maintenance: Schedule maintenance based on usage and environment. Periodically grease acme screws and check for lubricant leakage in worm gearboxes. Refer to the Use and Maintenance Manual for detailed guidance.

Lubricants Table: Provides specific lubricant types and quantities for different screw jack models.

Product Label Information: Each screw jack has a label with product code, ratio, stroke length, linear speed, delivery date, and serial number for identification and ordering spare parts.

Selection Inquiry: Data sheets for screw jacks with travelling screws or nuts include application details, load requirements, mounting options, and environmental conditions. Accessories and additional features are also listed.

Check Sheet: Includes dimensions, stroke limits, and pre-commissioning checks such as breather plug positioning, lubrication, and stroke limit device connection.

Screw Jack Lifting Systems Overview
Servomech provides comprehensive solutions for screw jack systems, including various configurations and components. The systems can be customized with screw jacks featuring flanges for motor mounting or input shafts, and are compatible with AC, DC, and servomotors. Inverter drives and control options for axial position and linear speed are available, along with bevel gears and transmission shafts.

Technical Support and Resources
Servomech offers technical support for screw jack selection, lifetime estimation, and system layout drawings. Customers can access 3D models and 2D drawings via a web configurator or by contacting the engineering department.

Single Motorized Screw Jack Configurations
Various layouts are available for single motorized screw jacks, including two, three, and four-point lifting systems. Options include screw jacks with plug-in flanges, bell-housings, and single input shafts, compatible with IEC B5, B14, and B3 motors.

ATL and BSA Series
The ATL series with acme screws offers seven sizes with load capacities from 4 kN to 80 kN and linear speeds from 1.5 mm/s to 150 mm/s. The BSA series with ball screws also provides seven sizes, supporting loads from 4 kN to 60 kN and speeds from 1.5 mm/s to 120 mm/s.

Linear Actuators
Several series of linear actuators are available, including:

UAL Series (acme screw): 5 sizes, 2 kN to 15 kN load capacity, 20 mm/s to 500 mm/s speed.
UBA Series (ball screw): 5 sizes, 2 kN to 15 kN load capacity, 40 mm/s to 500 mm/s speed.
SEA Series (acme screw): 5 sizes, 15 kN to 200 kN load capacity, 2 mm/s to 70 mm/s speed.
CLA Series (acme screw): 3 sizes, 8 kN to 25 kN load capacity, 4 mm/s to 56 mm/s speed.
CLB Series (ball screw): 3 sizes, 6 kN to 25 kN load capacity, 5 mm/s to 80 mm/s speed.

Catalog excerpts

SERVOMECH Screw Jacks MA Series Screw Jacks - high efficiency ■ synthetic oil lubricated worm gearbox • load capacity ranging from 5 kN to 350 kN ■ acme screw diameter SJ Series Screw Jacks - standard performances 30 % over 10 min (20 % over 1 hour) ■ synthetic grease lubricated worm gearbox • load capacity ranging • acme screw diameter This catalogue contents are under publisher copyright and may not be reproduced unless permission is agreed. Every care has been taken to ensure the accuracy of the information contained in this catalogue, but no liability can be accepted for any errors or omissions....

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Screw jacks INDEX 1. General page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page page 2. MA Series screw jacks 3. SJ Series screw jacks

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Screw jacks Screw jacks overview Screw jacks transform a rotary motion from an electric, hydraulic or pneumatic motor or even manual operation into a linear movement in a vertical (push-pull lifting) or horizontal position. Screw jacks can be installed as a single unit or in lifting systems with different layouts connected by driveshafts, couplings and bevel gearboxes. Screw jacks enable the synchronized constant movement of lifting systems even with a varying load. SERVOMECH screw jacks are able to work under either push or pull load conditions and mounted vertically upward, downward or horizontally....

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Screw jacks Materials and components Acme screws, profile according to ISO 2901 ... ISO 2904 ▪ material: steel C 43 (UNI 7847) ▪ subjected to straightening process to ensure the regular alignment in operation ▪ max. pitch error ± 0.05 mm over 300 mm thread length Threaded bars available on stock: Bronze travelling nut , profile according to ISO 2901 ... ISO 2904 ▪ material: bronze nut with 1-start thread bronze EN 1982 - CuAl9-C bronze nut with multiple starts thread bronze EN 1982 - CuSn12-C ▪ max. axial backlash with new travelling nut: (0.10 ... 0.12) mm Ball screws ▪ material: steel 42 CrMo...

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Screw jacks Acme screw jacks SERVOMECH acme screw jacks MA Series travelling screw (Model A) travelling nut (Model B) MA 5 MA 10 MA 25 MA 50 MA 80 MA 100 MA 200 MA 350 SJ Series travelling screw (Model A) travelling nut (Model B) MA Series: SJ Series: high efficiency screw jacks standard performances screw jacks 8 standard sizes 14 standard sizes with load capacity from 5 kN to 350 kN with load capacity from 5 kN to 1 000 kN Model A: travelling screw Model B: travelling nut 1- start acme screw 1- start acme screw from Tr 18 × 4 to Tr 100 × 16 from Tr 18 × 4 to Tr 160 × 16 2-starts acme screw...

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Screw jacks Ball screw jacks SERVOMECH ball screw jacks MA BS Series travelling ball screw (Model A) travelling ball nut (Model B) BS 20×5 BS 25×6 BS 25×6 BS 32×5 BS 32×5; BS 32×10; BS 32×20; BS 32×32 BS 40×10; BS 40×20; BS 40×40 BS 50×10; BS 50×20 travelling ball nut (Model B) SJ 5 SJ 10 SJ 25 MA BS Series: SJ BS Series: high efficiency screw jacks, standard performances screw jacks, suitable for continuous operation also, Model B (travelling nut) available only, duty cycle up to 100 %, duty cycle up to 70 %, input speed up to 3 000 rpm input speed up to 1 500 rpm 8 standard sizes 8 standard...

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Screw jacks Models Both MA and SJ Series screw jacks are available in two models: with travelling screw (Model A) with travelling nut (Model B) The choice of the model depends on the configuration and requirements of the application. The performances are in general the same for both models. SERVOMECH screw jacks can be operated in vertical or horizontal planes, or angles in-between. Input options available: free shaft, double free shaft, motor flange with or without second shaft. travelling ball screw (Model A) travelling ball nut (Model B) The bronze nut is integral with the worm wheel. The...

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Screw jacks Versions INPUT SHAFT ROTATION – SCREW OR NUT LIFTING DIRECTION Vers.1: single input shaft Vers.2: double free input shaft Vers.3: flange and hollow shaft input for IEC motor Vers.4: flange and hollow shaft input for IEC motor with second free input shaft Vers.5: Vers.1 + bell housing and coupling for IEC motor Vers.6: Vers.2 + bell housing and coupling for IEC motor SCREW JACK MOUNTING POSITIONS UPWARD (U)

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Screw jacks Screw jacks selection criteria Working time during reference time period Trif [min] × 100 Reference time period Trif [min] Trif - reference time period, expressed in minutes: Tref = 10 minutes for short, but frequent working cycles Tref = 1 hour (60 min) for long, but infrequent working cycles The screw jack duty cycle Fi [%] allowed is the percentage of time referred to the reference time period Tref during which the screw jack can operate under maximum load conditions - stated in this catalogue - at 25°C environment temperature, to avoid the risk of internal parts overheating. Therefore,...

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Screw jacks In order to make a correct screw jack selection, we recommend the following selection procedure: 1. Model: - Model A – travelling screw - Model B – travelling nut 2. SERVOMECH screw jack series: - MA Series: high efficiency screw jack with acme screw, oil lubricated - SJ Series: standard performances screw jack with acme screw, grease lubricated 3. Screw jack size: - Pull or push load - Stroke - Linear speed - Power required 4. Input version: - Vers.1: single free input shaft - Vers.2: double free input shaft - Vers.3: flange and hollow shaft input for IEC motor - Vers.4: flange and...

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Screw jacks 2. SERVOMECH screw jacks series: The screw jack’s duty cycle and the duty cycle required by the application Fu [%] are the most important factors in choosing between the two available screw jacks series, as previously described. The duty cycle required by the application Fu [%] has to be lower than or equal to the working duty cycle rating the screw jack can perform Fi [%], inclusive the environment temperature correction factor (fT): Fu [%] £ Fi [%] Here below are values of the max. duty cycle Fi [%] at 25°C environment temperature for the SERVOMECH screw jacks series: Duty cycle...

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Acme Screw Jacks

Acme Screw Jacks

Catalog excerpts

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