What’s the working temperatures of our screw jack actuator?

Normal operating conditions are -20ºC to 80ºC. Please consult for applications that require temperatures outside this range.

What’s the tolerances and backlash of our screw jack lift?
  • Machining precision level eight
  • Radial play is 0.2mm
  • Trapezoidal screw end play is 0.15mm
  • Lifting screw outer diameter and sleeve diameter free tolerance is 0.2mm
  • Worm shaft and gear play is ± 3 degrees for ratio N, and ± 5 degrees for ratio L
What’s stop nut and how are they used?

Stop nut are offered as options for screw jacks, and are not to be used as operating limits. Engaging the stop may prevent damage to your structure but will most likely damage the jack. To control jack or actuator travel, include limit switches in the system design. Including stops may increase the closed height of the jack and the length of the protection tube.

What do you need to consider when adding a protective boots?

Closed height dimensions may increase when boots are added. Standard material is Neoprene coated nylon. Special boot material is available. Horizontal screw applications may require boot guides.

Are Machine Screw Actuators corrosion resistant?

Stainless steel jacks are inherently corrosion resistant. All exposed surfaces are stainless steel and aluminum bronze. Most other jacks can be modified with special finishes, coatings, and seals. Contact with your requirements.

Finished for screw jack gearbox

  • Gray enamel is the standard finish.
  • Miniature jacks with aluminum housings (2.5kn and 5kn) are unpainted. Clear coat anodizing is a uniform coating process that increases the corrosion
    resistance and wears properties of aluminum housings. It will not flake or peel.
  • Standard epoxy is comprised of a two-component polyamide primer, and a two-component, low VOC, polyurethane topcoat.
  • STEEL epoxy finish provides a hard, non-toxic finish. It is comprised of a two-part, lead-free epoxy primer with a two-part polyamide epoxy topcoat.
  • Outdoor paint processing is an exclusive paint process that protects against corrosion due to harsh outdoor environments. It incorporates rigorous surface preparation with a premium epoxy primer and topcoat and stainless steel hardware resulting in a durable, corrosion-resistant finish.
  • Electroless nickel plating is a thin, uniform coating. When applied to jack housings, it provides superior corrosion resistance and improved wear resistance, while having little effect on the fit of mating components.
What grease does our worm gear jacks lubricated?

Our worm gear jacks are lubricated with 0# or 1# lithium grease prior to shipment. You can find more specific information from our Operation & Maintenance Manuals.

Can the SIJIE screw jack operate at high speeds?

The travel Speeds of the screw actuators mainly depend on the input RPM, load, internal ratio and lead of the screw. Maximum allowable travel speeds for machine screw jacks are typically slower than ball screw jacks. Worm gear jacks have slower travel speeds than bevel gear jacks.

For our model SJB high-speed screw actuator, it uses both ball screw and bevel gear, which make the speed quite fast. Pay attention that the input horsepower to these screw jacks should not exceed the hp rating shown in the specifications tables. Maximum RPM should not exceed 1500.

What is the allowable duty cycle of a worm gear screw jack?

The worm gear actuators efficiency is low, so the duty cycle is also low at the rated load. If you reduce the load or increase model NO, the duty cycle can be increased. Talk to our engineering sales for more information.

What is the maximum input RPM for our Screw Jack?

Maximum input RPM may be slower than 1500 RPM depending on the dynamic load and other factors specific to the application. You can contact and talk with an application engineer.

Can screw jack withstand the side load?

The load must be positioned axially. The standard screw jack is not designed for dynamic side loads. Static side loads are limited. Where side thrusts are present, the loads should be guided and let the guides take the side thrust especially when long travel length is involved. Even a small side load can exert great force on the housings and bearings and increase the operating torque. Contact for technical assistance.

What is screw jack duty cycle?

The duty cycle is the relationship between operation time and rest time. The allowable duty cycle for screw jack actuator is based upon several application variables such as load, speed, and temperature. Contact and talk with an application engineer about your requirements.

What is the life of the worm gear actuator and how is our wanrranty?

The life of a machine screw actuator varies considerably due to extent of lubrication, or improper maintenance, eccentric loading, abrasive, chemical, overloading, excessive heat, , etc.

SIJIE Industrial Co., LTD warrants that its screw jack sold will be free of defects in material and workmanship in a period of 13month from the original date of receipt.  During this period, SIJIE will repair or replace defective parts free of charge.

This warranty covers only normal use of the products. Sijie will not repair or replace any parts that become unusable and show clear evidence of improper maintenance, eccentric loading, overloading, excessive heat, chemical or abrasive wear, tampering or abuse. Equipment and accessories not manufactured by Sijie are warranted only to the extent the manufacturer warrants them, and only if the claimed defect arose during normal use, application and service. Equipment that has been altered or modified by anyone without Sijie’s authorization is not warranted. Except as stated herein, Sijie makes no other warranties, express or implied including warranties of merchantability and fitness for a particular purpose.

screw jack catalog

Screw Jack Catalog

screw jack operation instruction

Maintenance Manual

screw jack Maintenance Manual

Operation Instruction