Screw jack

Screw jack with worm gears is widely used in various industries such as machinery, metallurgy, construction, chemical, medical, and cultural health sectors. It can accurately control and adjust the lifting or advancement height according to a certain program. It can be directly powered by an electric motor or other power sources, or operated manually.

Screw jack, the SWL series worm screw jack is a basic lifting component that complies with the JB/T8809—2010 standard (formerly JB/T8809—1998, JB/ZQ4391—86). It has a load capacity of 2.5 to 120 tons. It boasts advantages such as compact structure, small size, light weight, wide power sources, low noise, easy installation, flexible operation, multiple functions, various matching forms, high reliability, and long service life.

The screw jack, also known as the screw transmission mechanism, is primarily used to convert rotational motion into linear motion or vice versa. There are those that mainly transmit motion, such as the feeding screw of machine tool worktables, and others that adjust the relative positions of parts. Screw jacks are divided into sliding friction and rolling friction mechanisms. The sliding screw and nut mechanism is simple in structure, easy to process, and cost-effective to manufacture, featuring an automatic locking function, but it has a high friction torque and low transmission efficiency. The ball screw and nut mechanism, although more complex in structure and higher in manufacturing cost and non-self-locking, boasts its major advantages: low friction torque, high transmission efficiency, high precision, good system stiffness, reversible motion, and a long service life. The screw jack consists of a worm gear reducer and a screw, with the reduction component being the worm gear. It uses the worm to drive the worm gear for deceleration. The worm gear is equivalent to the nut of the lifting screw and matches with it.

The lifting speed of the screw jack is equal to the worm input speed divided by the worm gear reduction ratio, then multiplied by the screw pitch, cylindrical gear reducer. Due to its structural nature, such screw jacks typically use grease lubrication. For maintenance and care, some series opt for oil lubrication, which offers the advantages of longer lifespan and more stable operation compared to those using grease lubrication. Planetary gear reducer [1].

Product Application

Input speed: 1500 rpm, lifting speed: 2.7 m/min. Available in various structural types and assembly methods; lifting height customizable to customer requirements. The device features an automatic locking mechanism.

Structural Style

Hoists are divided into categories based on their structural type:

Model 1 - Lead screw performs both rotational movement and axial displacement.

Type 2 - The screw performs a rotating motion. The nut on the screw moves axially.

Assembly Type

Each lifting mechanism is further divided into two assembly types:

Type A - Screw (or Nut) moves upwards.

B-type - lead screw (or nut) moves downwards.

Lead screw head type

1-Type screw with structural design

The top section is:

I (Cylindrical), II (Flanged), III (Threaded), IV (Flat Head) - four types.

The screw head section of the 2-type structural style is available in two forms: I (cylindrical) and III (threaded).

Transmission Ratio

Lifts are available in two gear ratios, namely standard (P) and slow (M).

Screw Thread Protection

The protection of the 1-type lifting screw is divided into: Basic, Anti-Rotational (F), and Enclosed (Z) types.

2-Type lifting screw protection is divided into: Basic Type and Protective Cover Type (Z) [2].

Product Features

Broadcast Editor

1. The JWM type (trapezoidal screw type) is suitable for low-speed, low-frequency applications. Its main components include precision trapezoidal screw pairs and high-precision worm gear pairs.

2. Economical pricing, compact structure, easy operation, and convenient maintenance.

3. Low speed, low frequency: Primarily used in high-load, low-speed applications where frequent operation is not required.

4. Maintain Load Capacity: The trapezoidal screw features an automatic locking function, ensuring load capacity is maintained even without a braking device.