Product Description

Manual operated hand wheel Screw Jacks, Manual Screw Jack is composed of hand wheel or hand crank and a worm gear screw jack, hand crank screw jack
A manual screw jack is consist of a hand wheel and a complete worm gear screw jack. All screw jacks can be moved manually via a handwheel. To do this, 1 input shaft shall be available on the screw jack for the connection of the handwheel. The screw jack makes it possible to transform the rotary motion provided by a handwheel, into linear motion that allows push or pull vertical lifting and horizontal positioning. They can be used to lift, pull, move, or align any type of load with perfect synchronism, which is difficult to achieve with other types of actuators.They can be applied either with vertical mountings facingup or down, or with horizontal mountings.
Manual screw jacks are available in load capacity 0.25 ton, 0.5 ton, 1 ton, 2 ton, 2.5 ton, 3 ton, 5 ton, 10 ton, 15 ton and 20 ton, heavy load larger than 20 ton capacity, manual operated screw jack is not recommended. They are ideal solutions for applications where electricity or power generators is inconvenient or dangerous, or in case of power failure, light weight, low duty cycle, low speed, low target cost, short stroke, and intermittent positioning applications. If must be not backdriving, a self locking machine screw jack with handwheel is the best choice. If high speed ball screw jack with handwheel, locking mechanisms need to be considered. If a brake motor is used, the brake shall be un-clamped firstly, so to allow for movement.

Cast Iron Hand wheel Diameter 125mm, 160mm, 26567X3, registered Capital 500000CNY) is a leading manufacturer and supplier of Screw Jacks (Mechanical Actuators), Bevel Gearboxes, Lifting Systems, Electric Linear Actuators, Gearmotors and Speed Reducers, Others Linear Motion and Power Transmission Products in China. Most of them are passed CE certificates. We are located in Chang An, Xihu (West Lake) Dis. guan, Guang dong in China. We are an audited professional manufacturer and supplier by SGS (Serial NO.: QIP-ASI192186) and BV (Serial NO.: MIC-ASR257162) organizations. We have a strict quality system, with senior engineers, experienced skilled workers and practiced sales teams, and consistently provide the customers with the best engineered solution for precision linear actuation, power transmission and mechanical jacking systems. CZPT Industry guarantees quality, reliability, performance and value for today’s demanding industrial applications.

Company Advantages
* One of the biggest orders with 1750 units screw lift jacks.
* Standard products with 2D Drawings(DXF, DWG, PDF) and 3D CAD Model(STEP).
* 100% quality assured with double quality inspections. Original Inspection Reports, Operation Manual, and Book Catalogue are put into the packages. 
* 100% safety transportation with strong standard export plywood cases materials (free fumigation). 
* International standard materials for all standard products. 
* Custom design available, OEM service available, Free engineering advice and Customer label available.

Products List
* Manual Screw Jacks
* Electric Screw Jacks
* Screw Jacks Series: 
Cubic Screw Jack JTC Series, Machine Screw Jack JTW Series, Trapezoidal Screw Jack JT Series, Worm Screw Jack JTM Series, Stainless Steel Screw Jack JSS Series, Through Hole Screw Jack JTH Series, Ball Screw Jack JTB Series, Cubic Ball Screw Jack JTD Series, Bevel Gear Screw Jack JTS Series, and Electric Cylinder JTE Series.
* Bevel Gearboxes Series: 
Cubic Bevel Gearbox JTP Series, Hollow Shaft Gearbox JTPH Series, Input Flange Gearbox JTPF Series, Input Flange and Hollow shaft Gearbox JTPG Series, Stainless Steel Gearbox JTP Series, Aluminum Gearbox JTA Series, and Spiral Bevel Gearboxes JT Series.
* Screw Jack Lifting Systems and Accessories: 
2jacks lifting system, 3jacks lifting system, 4jacks lifting system, 6jacks lifting system, 8jacks lifting system……14jacks lifting system. Lifting systems accessories cover ac, dc motors, geared motors, servo motors, stepper motors, handwheels, couplings, universal joints, telescopic universal joints, connecting shafts, cardan shafts, limit switches, proximity switches, safety nut, travel nut, rod ends, stop nuts, pillow block bearings, flange blocks, motor flange nema or iec, encoder, potentiometer, frequency converter, position indicators, trunnion plate, and trunnion mounting brackets. 
* Electric Linear Actuators Series:
Electro Mechanical Actuators LA Series, Electro Mechanical Actuators LAP Series. 
* Gear Reducers Series: 
Helical Gear Reducers R Series, Helical Bevel Gear Reducers K Series, Parallel Shaft Helical Gear Reducers F Series, Helical Worm Gear Reducers S Series, Helical Gear Motor GMH/GMV Series, and Worm Gear Reducers NMRV Series.   

Customers Distribution Countries
* American Countries: United States, Mexico, Canada, Chile, Argentina, Xihu (West Lake) Dis.via, Brazil, Colombia, Guatemala, Honduras, Panama, Peru.
* European Countries: Germany, France, United Kingdom, Italy, Spain, Poland, Romania, Netherlands, Belgium, Greece, Czech Republic, Portugal, Sweden, Hungary, Austria, Switzerland, Bulgaria, Denmark, Finland, Slovakia, Norway, Ireland, Georgia, Slovenia.
* Asian Countries: Malaysia, Indonesia, Singapore, Philippines, Vietnam, Thailand, India, Israel, Cambodia, Myanmar, Sri Lanka, Maldives, Pakistan, Iran, Turkey, Jordan, Saudi Arabia, Yemen, Oman, United Arab Emirates, Qatar, Georgia, Armenia.
* Oceanian Countries: Australia, New Zealand.
* African Countries: Egypt, Ethiopia, Nigeria, South Africa, Zambia, Mozambique. 

Screw Sizes and Their Uses

Screws have different sizes and features. This article will discuss screw sizes and their uses. There are 2 main types: right-handed and left-handed screw shafts. Each screw features a point that drills into the object. Flat tipped screws, on the other hand, need a pre-drilled hole. These screw sizes are determined by the major and minor diameters. To determine which size of screw you need, measure the diameter of the hole and the screw bolt’s thread depth.

The major diameter of a screw shaft

The major diameter of a screw shaft is the distance from the outer edge of the thread on 1 side to the tip of the other. The minor diameter is the inner smooth part of the screw shaft. The major diameter of a screw is typically between 2 and 16 inches. A screw with a pointy tip has a smaller major diameter than 1 without. In addition, a screw with a larger major diameter will have a wider head and drive.
The thread of a screw is usually characterized by its pitch and angle of engagement. The pitch is the angle formed by the helix of a thread, while the crest forms the surface of the thread corresponding to the major diameter of the screw. The pitch angle is the angle between the gear axis and the pitch surface. Screws without self-locking threads have multiple starts, or helical threads.
The pitch is a crucial component of a screw’s threading system. Pitch is the distance from a given thread point to the corresponding point of the next thread on the same shaft. The pitch line is 1 element of pitch diameter. The pitch line, or lead, is a crucial dimension for the thread of a screw, as it controls the amount of thread that will advance during a single turn.

The pitch diameter of a screw shaft

When choosing the appropriate screw, it is important to know its pitch diameter and pitch line. The pitch line designates the distance between adjacent thread sides. The pitch diameter is also known as the mean area of the screw shaft. Both of these dimensions are important when choosing the correct screw. A screw with a pitch of 1/8 will have a mechanical advantage of 6.3. For more information, consult an application engineer at Roton.
The pitch diameter of a screw shaft is measured as the distance between the crest and the root of the thread. Threads that are too long or too short will not fit together in an assembly. To measure pitch, use a measuring tool with a metric scale. If the pitch is too small, it will cause the screw to loosen or get stuck. Increasing the pitch will prevent this problem. As a result, screw diameter is critical.
The pitch diameter of a screw shaft is measured from the crest of 1 thread to the corresponding point on the next thread. Measurement is made from 1 thread to another, which is then measured using the pitch. Alternatively, the pitch diameter can be approximated by averaging the major and minor diameters. In most cases, the pitch diameter of a screw shaft is equal to the difference between the two.

The thread depth of a screw shaft

Often referred to as the major diameter, the thread depth is the outermost diameter of the screw. To measure the thread depth of a screw, use a steel rule, micrometer, or caliper. In general, the first number in the thread designation indicates the major diameter of the thread. If a section of the screw is worn, the thread depth will be smaller, and vice versa. Therefore, it is good practice to measure the section of the screw that receives the least amount of use.
In screw manufacturing, the thread depth is measured from the crest of the screw to the root. The pitch diameter is halfway between the major and minor diameters. The lead diameter represents the amount of linear distance traveled in 1 revolution. As the lead increases, the load capacity decreases. This measurement is primarily used in the construction of screws. However, it should not be used for precision machines. The thread depth of a screw shaft is essential for achieving accurate screw installation.
To measure the thread depth of a screw shaft, the manufacturer must first determine how much material the thread is exposed to. If the thread is exposed to side loads, it can cause the nut to wedge. Because the nut will be side loaded, its thread flanks will contact the nut. The less clearance between the nut and the screw, the lower the clearance between the nut and the screw. However, if the thread is centralized, there is no risk of the nut wedgeing.

The lead of a screw shaft

Pitch and lead are 2 measurements of a screw’s linear distance per turn. They’re often used interchangeably, but their definitions are not the same. The difference between them lies in the axial distance between adjacent threads. For single-start screws, the pitch is equal to the lead, while the lead of a multi-start screw is greater than the pitch. This difference is often referred to as backlash.
There are 2 ways to calculate the pitch and lead of a screw. For single-start screws, the lead and pitch are equal. Multiple-start screws, on the other hand, have multiple starts. The pitch of a multiple-start screw is the same as its lead, but with 2 or more threads running the length of the screw shaft. A square-thread screw is a better choice in applications requiring high load-bearing capacity and minimal friction losses.
The PV curve defines the safe operating limits of lead screw assemblies. It describes the inverse relationship between contact surface pressure and sliding velocity. As the load increases, the lead screw assembly must slow down in order to prevent irreversible damage from frictional heat. Furthermore, a lead screw assembly with a polymer nut must reduce rpm as the load increases. The more speed, the lower the load capacity. But, the PV factor must be below the maximum allowed value of the material used to make the screw shaft.

The thread angle of a screw shaft

The angle between the axes of a thread and the helix of a thread is called the thread angle. A unified thread has a 60-degree angle in all directions. Screws can have either a tapped hole or a captive screw. The screw pitch is measured in millimeters (mm) and is usually equal to the screw major diameter. In most cases, the thread angle will be equal to 60-degrees.
Screws with different angles have various degrees of thread. Originally, this was a problem because of the inconsistency in the threading. However, Sellers’s thread was easier to manufacture and was soon adopted as a standard throughout the United States. The United States government began to adopt this thread standard in the mid-1800s, and several influential corporations in the railroad industry endorsed it. The resulting standard is called the United States Standard thread, and it became part of the ASA’s Vol. 1 publication.
There are 2 types of screw threads: coarse and fine. The latter is easier to tighten and achieves tension at lower torques. On the other hand, the coarse thread is deeper than the fine one, making it easier to apply torque to the screw. The thread angle of a screw shaft will vary from bolt to bolt, but they will both fit in the same screw. This makes it easier to select the correct screw.

The tapped hole (or nut) into which the screw fits

A screw can be re-threaded without having to replace it altogether. The process is different than that of a standard bolt, because it requires threading and tapping. The size of a screw is typically specified by its major and minor diameters, which is the inside distance between threads. The thread pitch, which is the distance between each thread, is also specified. Thread pitch is often expressed in threads per inch.
Screws and bolts have different thread pitches. A coarse thread has fewer threads per inch and a longer distance between threads. It is therefore larger in diameter and longer than the material it is screwed into. A coarse thread is often designated with an “A” or “B” letter. The latter is generally used in smaller-scale metalworking applications. The class of threading is called a “threaded hole” and is designated by a letter.
A tapped hole is often a complication. There is a wide range of variations between the sizes of threaded holes and nut threads, so the tapped hole is a critical dimension in many applications. However, even if you choose a threaded screw that meets the requisite tolerance, there may be a mismatch in the thread pitch. This can prevent the screw from freely rotating.