Acme Screw Jacks
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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...

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

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...

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...

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 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...

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....

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)

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....

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...

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...