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Product Description

Declutchable gear override of ZHangZhoug CHINAMFG Auto-Tech Co,.Ltd is a rotary manual control device used to support the normal operation of pneumatic actuator even the emergency situation happened. The gear override is used to connect pneumatic actuators with rotary valves. It has the compact design and light weight. The unique design allows it provide high output torque by simply rotating the hand-wheel. CHINAMFG provides several optional size of gear override to fit different size of valves and actuators. The standard ISO 5211 Mounting pad allows it be installed directly. It is primarily used to manually open and close 90-degree angular travel valves.




Parts Name




Aluminum Alloy



Aluminum Alloy


Drive Gear

Ductile Iron


Gear Cover

Aluminum Alloy


Upper Male Square Stem

Carbon Steel


Handwheel Shaft

Carbon Steel with Chrome Plated



Plated Carbon Steel


Position Lever Assy

Plated Carbon Steel


Position Lock Assy

Plated Carbon Steel


Cover Bolts

Carbon Steel with Zinc Plated


Limit Stops

Stainless Steel


Gear Cover Bolts

Carbon Steel with Zinc Plated


Shaft Bushings

Carbon Steel


Grease Fitting






O Rings



JSD-1 101 16 14 14 19 90 185 160 53 50 6 8 70 50 57 70 M6X12 M6X12 M8X12 155
JSD-2 110 17 17 17 25 124 225 200 74 70 8 10 102 70 70 102 M8X13 M8X13 M10X16 200
JSD-3 124 23 22 22 25 140 308 320 126 102 10 12 125 102 89 125 M10X16 M12X20 M12X20 400
JSD-4 185 25 27 27 29 185 400 450 186 125 12 14 140 102 108 140 M10X16 M12X20 M16X25 500



Gear Ratio

Output Torque (Nm)














We are specializing in manufacturing pneumatic actuator, electric actuator, pneumatic actuated butterfly and ball valve, electric actuated butterfly and ball valve, Limited Switch box and other Accessories………



1.Price: As we are the professional manufacture in valve actuators and accessories, we ensure that the price offered must be very competitive compare with others.

2. Raw material inspection: All material test high quality, and keep in warehouse.

3. Workers: All workers training 3 monthes, skilled workers on production line.

Sample Order

We will charge express fee only for old customers in generally, and for new customers we will charge 50% of the units cost and express fee mostly. (It can be discussed, we keep options always.)


Delivery Time

We usually take 20days for official orders after received the prepayment, And Sample orders will be ready within 7days.


Quality Control

We got very strict and complete quality system to ensure that each product will meet quality requirements as per clients, incoming quality control, final quality control, out-going quality control. Meanwhile, all of the products will be strictly inspected before delivery.”‘ Quality First, Service First” that we are pursuing All the time.


Warranty Period

18 months from the date we signed the contract or PI. Technical support for the whole life. 


Payment Terms And Conditions

1. TT Terms: The payment will be 30% of prepayment by direct bank remittance (T/T),remaining 70% before Shipment or the copy of BL send by us Via Fax or Email.

2. L/C Terms: Payment by L/C at sight and Unrestricted. (L/C must allow 30days minimum from the shipment date of presentation of documents for negotiation, all the clauses within L/C must be clear, concise and acceptable. Do not allow special clauses, terms and conditions.)


Competitive Price

We provide competitive price, good quality and best service to reach the CHINAMFG goal.



Custom-made is acceptable.

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Application: Motor, Pneumatic Actuator
Function: Change Drive Torque, Manual Control
Layout: Three-Ring
Hardness: Hardened Tooth Surface
Installation: Vertical Type
Type: Worm Gear Box
US$ 40/Piece
1 Piece(Min.Order)

Request Sample



Customized Request

worm gearbox

Calculating Gear Ratio in a Worm Reducer

The gear ratio in a worm reducer is determined by the number of teeth on the worm wheel (also known as the worm gear) and the number of threads on the worm shaft. The gear ratio formula for a worm reducer is:

Gear Ratio = Number of Teeth on Worm Wheel / Number of Threads on Worm Shaft

For example, if the worm wheel has 60 teeth and the worm shaft has a single thread, the gear ratio would be 60:1.

It’s important to note that worm reducers have an inherent self-locking property due to the angle of the worm threads. As a result, the gear ratio also affects the mechanical advantage and the system’s ability to resist backdriving.

When calculating the gear ratio, ensure that the worm reducer is properly designed and that the gear ratio aligns with the desired mechanical characteristics for your application. Additionally, consider factors such as efficiency, load capacity, and speed limitations when selecting a gear ratio for a worm reducer.

worm gearbox

Energy Efficiency of a Worm Gearbox: What to Expect

The energy efficiency of a worm gearbox is an important factor to consider when evaluating its performance. Here’s what you can expect in terms of energy efficiency:

  • Typical Efficiency Range: Worm gearboxes are known for their compact size and high gear reduction capabilities, but they can exhibit lower energy efficiency compared to other types of gearboxes. The efficiency of a worm gearbox typically falls in the range of 50% to 90%, depending on various factors such as design, manufacturing quality, lubrication, and load conditions.
  • Inherent Losses: Worm gearboxes inherently involve sliding contact between the worm and worm wheel. This sliding contact generates friction, leading to energy losses in the form of heat. The sliding action also contributes to lower efficiency when compared to gearboxes with rolling contact.
  • Helical-Worm Design: Some manufacturers offer helical-worm gearbox designs that combine elements of helical and worm gearing. These designs aim to improve efficiency by incorporating helical gears in the reduction stage, which can lead to higher efficiency compared to traditional worm gearboxes.
  • Lubrication: Proper lubrication plays a significant role in minimizing friction and improving energy efficiency. Using high-quality lubricants and ensuring the gearbox is adequately lubricated can help reduce losses due to friction.
  • Application Considerations: While worm gearboxes might have lower energy efficiency compared to other types of gearboxes, they still offer advantages in terms of compactness, high torque transmission, and simplicity. Therefore, the decision to use a worm gearbox should consider the specific requirements of the application, including the trade-off between energy efficiency and other performance factors.

When selecting a worm gearbox, it’s essential to consider the trade-offs between energy efficiency, torque transmission, gearbox size, and the specific needs of the application. Regular maintenance, proper lubrication, and selecting a well-designed gearbox can contribute to achieving the best possible energy efficiency within the limitations of worm gearbox technology.

worm gearbox

How Does a Worm Gearbox Compare to Other Types of Gearboxes?

Worm gearboxes offer unique advantages and characteristics that set them apart from other types of gearboxes. Here’s a comparison between worm gearboxes and some other common types:

  • Helical Gearbox: Worm gearboxes have higher torque multiplication, making them suitable for heavy-load applications, while helical gearboxes are more efficient and offer smoother operation.
  • Bevel Gearbox: Worm gearboxes are compact and can transmit motion at right angles, similar to bevel gearboxes, but worm gearboxes have self-locking capabilities.
  • Planetary Gearbox: Worm gearboxes provide high torque output and are cost-effective for applications with high reduction ratios, whereas planetary gearboxes offer higher efficiency and can handle higher input speeds.
  • Spur Gearbox: Worm gearboxes have better shock load resistance due to their sliding motion, while spur gearboxes are more efficient and suitable for lower torque applications.
  • Cycloidal Gearbox: Cycloidal gearboxes have high shock load capacity and compact design, but worm gearboxes are more cost-effective and can handle higher reduction ratios.

While worm gearboxes have advantages such as high torque output, compact design, and self-locking capability, the choice between gearbox types depends on the specific requirements of the application, including torque, efficiency, speed, and space limitations.

China high quality Pneumatic Actuator Declutchable Manual Override Worm Gearbox   supplier China high quality Pneumatic Actuator Declutchable Manual Override Worm Gearbox   supplier
editor by CX 2024-02-26