screw jack parts

screw jack parts

screw jack


In this blog post, we will explore the various parts of a screw jack and their functions. Screw jacks are mechanical devices used for lifting heavy loads or applying large forces with a relatively small input force. Understanding the different components of a screw jack is crucial for its proper usage and maintenance.

Main Components of a Screw Jack

1. Screw Shaft

The screw shaft is the main part of a screw jack. It is a cylindrical rod with a helical groove or thread that allows linear motion when rotated. The pitch of the thread determines the lifting or lowering speed of the screw jack.

2. Worm Gear

The worm gear is a spiral-shaped gear that meshes with the screw shaft’s thread. It converts the rotary motion of the input shaft into linear motion along the screw shaft. The worm gear’s design ensures high gear ratio, providing mechanical advantage in lifting heavy loads.

3. Housing

The housing, also known as the gearbox, encloses the worm gear and provides protection and support to the internal components. It is typically made of durable materials such as cast iron or steel to withstand heavy loads and ensure the screw jack’s stability.

4. Bearings

Bearings are essential components that support and facilitate the smooth rotation of the screw shaft and worm gear. They reduce friction and ensure efficient power transmission, enhancing the overall performance and longevity of the screw jack.

5. Lubrication System

A screw jack requires proper lubrication to minimize friction and prevent premature wear and tear. The lubrication system consists of oil or grease reservoirs, oil seals, and lubrication points strategically located to ensure smooth operation and extend the screw jack’s lifespan.

6. Base Plate

The base plate provides a stable foundation for the screw jack, allowing it to be securely mounted on a surface. It is typically made of strong materials like steel and may feature pre-drilled holes for easy installation.

screw jack

What is a screw jack used for?

A screw jack is a versatile mechanical device with various applications across different industries. Here are some common uses:

1. Industrial Lifting

Screw jacks are employed for lifting heavy machinery, equipment, and structures in industrial settings. They provide stable and controlled vertical movement, making them ideal for precise positioning and height adjustment.

2. Mechanical Systems

Screw jacks are integral components in mechanical systems where linear motion or force amplification is required. They are often used in conveyor systems, assembly lines, presses, and other applications that involve pushing, pulling, or moving loads.

3. Stage and Theater Setup

Screw jacks are commonly used in stage and theater setups for raising and lowering props, platforms, and lighting equipment. Their precise control and ability to support heavy loads make them indispensable tools in creating dynamic and visually appealing performances.

4. Automotive Maintenance

In automotive maintenance and repair, screw jacks are used to lift vehicles, allowing mechanics to access the underside for inspections, repairs, or tire changes. Screw jacks provide a stable and secure lifting solution, ensuring the safety of both the vehicle and the personnel.

5. Construction and Infrastructure

Construction and infrastructure projects often require temporary support or leveling of structures. Screw jacks can be used to provide the necessary stability and adjustability, facilitating the construction process and ensuring structural integrity.

screw jack

What is the working principle of screw jack?

The working principle of a screw jack is based on the concept of mechanical advantage through a threaded screw and a worm gear. Here’s how it works:

1. Rotational Input

When a force is applied to rotate the input shaft, which is connected to the worm gear, the helical thread of the screw shaft interacts with the worm gear, causing it to move linearly.

2. Linear Motion

As the worm gear moves along the screw shaft, it engages with the screw’s thread, converting the rotary motion into linear motion. This linear motion results in the desired lifting or lowering of the load.

3. Mechanical Advantage

The thread pitch of the screw shaft determines the mechanical advantage of the screw jack. A smaller pitch provides finer control and slower lifting speed, while a larger pitch allows for faster lifting with less force exerted on the input shaft.

4. Self-Locking

A notable feature of screw jacks is their self-locking ability, which prevents the load from descending when the input force is removed. The friction between the threads of the screw and the worm gear keeps the screw jack in a stable position, ensuring the load remains elevated even without continuous input torque.

5. Reversibility

Screw jacks are reversible, meaning they can perform both lifting and lowering functions by simply reversing the rotational direction of the input shaft. This versatility allows for easy adjustment and adaptability in various applications.

What is the difference between a screw jack and a hydraulic jack?

While both screw jacks and hydraulic jacks are used for lifting heavy loads, they operate on different principles:

Screw Jack

– Screw jacks utilize mechanical advantage through the interaction between a threaded screw shaft and a worm gear.

– They require rotational input to achieve linear motion and lifting.

– Screw jacks are self-locking, providing load holding capability without continuous input force.

– They are generally slower in operation compared to hydraulic jacks but offer greater precision and control.

Hydraulic Jack

– Hydraulic jacks rely on the principle of Pascal’s law to amplify force using incompressible fluids.

– They use hydraulic pressure to generate lifting force, with a piston and cylinder arrangement.

– Hydraulic jacks can operate with a simple push or pull action.

– They are typically faster in operation and well-suited for heavy lifting tasks.

screw jack

Choosing and Customizing the Right Screw Jack

When selecting or customizing a screw jack, several parameters and practical considerations should be taken into account:

1. Load Capacity

Determine the maximum load the screw jack needs to lift or support. Consider both the static and dynamic loads, including any potential overload situations.

2. Lifting Speed

Evaluate the desired lifting or lowering speed required for the specific application. The screw jack’s pitch and gear ratio influence the speed at which it operates.

3. Travel Distance

Consider the vertical travel distance required for the screw jack. Ensure that the stroke length of the screw jack is sufficient to meet the application’s needs.

4. Environmental Conditions

Assess the operating environment, including factors such as temperature, humidity, dust, and corrosive substances. Choose a screw jack with suitable materials and protective measures to ensure long-term reliability.

5. Mounting and Integration

Consider the available space and mounting options within the application. Ensure compatibility and ease of integration with other mechanical systems or equipment.

HZPT is a leading manufacturer of industrial electric motors, gear reducers, and drives in China. Our products encompass a wide range of transmission equipment, including micro gear motors, brake motors, torque motors, DC motors, NMRV worm gear motors, bevel gear motors, WPRV worm gear reducers, helical gear reducers, servo worm gear reducers, parallel shaft helical gear reducers, spiral bevel gear reducers, screw lift systems, rigid face gear reducers, and planetary gear reducers. These products find extensive applications in various industries such as material handling, food processing, medical equipment, printing machinery, textile machinery, packaging machinery, office equipment, and instrumentation, making them the preferred choice for automated systems.

We specialize in the production and sale of screw jacks, offering high-quality and reliable products to our customers. Here are some key advantages of our screw jacks:

1. Robust Construction

Our screw jacks are constructed using durable materials and precision manufacturing techniques, ensuring their ability to handle heavy loads and withstand demanding industrial environments.

2. Smooth and Precise Operation

With careful design and high-quality components, our screw jacks offer smooth and precise linear motion control. This allows for precise positioning and accurate load handling.

3. Versatility and Adaptability

Our screw jacks can be customized to meet specific requirements, including load capacity, lifting speed, stroke length, and mounting options. This ensures optimal performance and seamless integration into various applications.

4. Self-Locking Capability

Our screw jacks incorporate self-locking features, providing reliable load holding without the need for continuous input force. This ensures safety and stability during operation.

5. Efficient Lubrication System

We pay special attention to the lubrication system of our screw jacks, ensuring optimal lubrication for smooth operation and extended service life. Proper lubrication minimizes friction and reduces wear and tear.

Choose HZPT screw jacks for your lifting and positioning needs, and experience top-quality products backed by our commitment to technological innovation and excellence in product quality.


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Ep Screw Jack Co., Ltd.

Mail: [email protected]

As one of leading manufacturers, suppliers and exporters of mechanical products in China, We offer reducers, sprockets, industrial and conveyor chain, belts, pulleys, gears, racks, gearboxes, motors, PTO Shafts, taper lock Bushing, vacuum Pumps, screw air compressors and many other products. Please contact us for details.