Crane dynamometer

Types of crane dynamometer

Electronic crane scales for heavy objects, also known as dynamometers, have developed over time to meet different operational requirements. These scales are significant in ensuring load-bearing equipment is not overloaded in industries like maritime, construction, and engineering.

Hook-on dynamometer

The hook-on dynamometers are designed to be integrated with lifting implements such as chains, hooks, and winches for a lift operation. This dynamometer comprises an electrical load cell positioned somewhere in-between the hooks and outputs a signal proportional to the electrical charge applied. The dynamometer receives the signal and transforms it to a load by using the equation between the load and the induced voltage. Hook-on dynamometers are portable and lightweight. Most of them are also waterproof and usable outdoors. This dynamometer is primarily used in construction works and ship handling at the ports when it is important to frequently change the operation site. It is ideal for quick, often temporary lifting operations.

Meter and gauge dynamometers

Meter dynamometers are similar to gauge dynamometers with lifting structure instruments and examples like the crane dynamometer and excavator dynamometer. The dynamometer is mounted on the crane so that the load is suspended from the dynamometer directly. The electric signal from the generator, which is a part of the machine, is proportional to the load to be lifted. The pressure on the spring, caused by the weight, causes a pointer set on the dial to revolve in proportion of the dial. A meter dynamometer indicates the weight of a lifted load, while a gauge dynamometer shows the strain measurement. This dynamometer is used for lifting heavy objects in a steady manner, such as in marine and construction industries. It works well when the equipment is stationary, providing accurate readings on forces.

Inline dynamometers

Inline dynamometers are also known as 'sensitive instruments.' These are positioned in line with the operation, emphasize high sensitivity, and are often employed for light or delicate lifting. They are integrated into wires to measure tension as precision instruments. Ships using wire ropes for hoisting can monitor cable tension using dynamometers, which helps avoid overloading.

Industrial applications of crane dynamometer

A digital crane scale is an important instrument in industries that need load management and safety monitoring during lifting operations. Its versatility and accuracy make it a significant instrument in construction, maritime, manufacturing, and other industrial works.

Safe load monitoring

One of the major objectives of the digital crane scale is to ensure safely monitor the load to be handled during lifting operations. Overloading can cause damage to the crane and structure as well as lead to fatal accidents. A crane dynamometer measures the weight of the load being lifted and indicates the magnitude of the load. This enables personnel to make necessary adjustments to avoid exceeding the required safety margins.

Guideline for lifting

In compliance with the OSHA (Occupational Safety and Health Administration) and other relevant regulations on lifting operations, a crane dynamometer provides critical data. It aids in the formation of safety practices by gathering evidence and stating the appropriate conditions under which lifting should be done. This information is also used in conjunction with other training techniques to enhance the routine and professionalism of lifting.

Risk assessment for heavy hoisting

Many industries have to carry out risk assessments before operating heavy hoisting. The dynamometer provides accurate load measurements that help identify potential hazards associated with lifting a certain load in a given situation. This enables the industry to weigh the benefits and risks of conducting lifting operations and motivates the industry to improve its safety features and strategies and concentrate on any risk aspects.

Engineering and construction

In the construction of a multi-story building or bridge, crane dynamometers are used to test materials and structure load. This helps to analyze whether materials meet the required standards, hence ensuring safety and performance.

Towing operations

Offshore towing and towing operations also use a crane dynamometer. It is fixed to the towing eye or hawser of a tug, and as it tows, the dragged vessel and dynamometer gives the master a reading of how many tons of pull he is exerting and how many tons the sea is regretting back (also called the back load). Marine dynamometers help capture all the load information so that improvements can be made to the tug and tow in the towing environment.

Product specifications and features of crane dynamometer

Technical specifications and features

• Maximum measuring range: The scale must possess the ability to bear the largest weight which will be lifted without fear of being damaged or causing distortion in the readings. Overloading the scale will have severe consequences, including inaccurate readings, and in the worst case, permanent damage to the scale platform.
• Measuring accuracy: It is important to analyze the accuracy of the product 's dynamics. High-accuracy dynamometers are crucial in delicate operations where minute differences in weight would affect safety or performance standards. Good accuracy diminishes the probability of measurement and provides the test with more reliable and reproducible results.
• Weathertight: Crane dynamometers should have a certain degree of weather tightness. This means that they can resist rain, water splashes, high humidity, and dry dust to be used outdoors. Often, these instruments should be weathertight as they are applied in works with unpredictable weather conditions or near water. This means that the construction of internal elements is resistant to external influences with a simultaneous guarantee of its efficiency.
• Load cell: Load cells are the core instruments that convert weights into measurable electrical signals. In a dynamometer, a metallic mass is expected to be placed on the load cell for an unknown electrical signal to be produced. Modern dynamometers usually have high-quality strain gauges serving as load cells for accuracy and sensitivity.
• Dynamometer housing: High-quality dynamometers are usually manufactured with a stainless steel housing to prevent corrosion, especially if used in seashore territories where salt is abundant in the atmosphere. Besides, there is a need for improvement on its physical strength to prevent damage from external impacts such as shock, drop, or sweep.

How to install

Crane scales, an expensive and delicate machine, have to be carefully installed to avoid using the machine in an uncalibrated state. Placed appropriately, the dynamometer measures horizontal forces exerted on the wire rope in a crane lifting system accurately.

Adjust the dynamometer at the middle position between the upper block pulley and the hook of the main hook of the wire rope so that the load passes through the dynamometer during the hoisting operation.

Ensure proper alignment with the pulley on both sides.

When the load comes to a still state, the dynamometer will show the reading of the tensioning load applied on the wire rope of the hoist.

The dynamometer used in the crane is not any special model like analog or digital; just make sure the dynamometer is of the correct measurement range rated for high loads. Ensure the dynamometer is in a balanced and centered position, ie, not swinging, rotating, or leaning. Operating on an uncalibrated dynamometer produces faulty results.

How to use

• Load attachment: Aload should be attached to the dynamometer by the dynamo calibrated. Ensure dynamo is at zero before loading the dynamo with dynamo calibration. This will give a general idea of the load weight that the equipment is carrying.
• Operational test: Operational tests should be conducted from time to time to ensure everything is functioning well. This will increase the instrumentation life and reliability. In the operational test, the load should be raised slowly enough so that the dynamometer has to register the correct value. Do not overload the dynamometer.

Maintenance and repair

• Battery: For battery-driven crane dynamometers, it is important to check the battery level before each use and replace the battery.
• Clean the scale regularly: To increase the accuracy and lifespan of the scale, weather, moisture, and dust should be cleaned regularly. Use a soft, damp cloth to clean the scale. Avoid sharp objects or abrasive material that can damage the dynamo sensors.
• Check settings and calibration: It is recommended that dynamomers be calibrated frequently. This can be done autonomously, but a professional should do it for large dynamo machines. Scaling items are used for calibration, which gives the correct weight values. This checks accuracy.
• Check for mechanical damage: Always look for cracks on the dynamo, hook, and load cell. Change the item if need be; left dynamometer ruins not just the instrument but also creates unsafe working conditions.
• Water penetration: If the dynamometer is rated for weather-tightness, it is important to check for water penetration. If water gets inside the machine, it damages internal destruction.

Q&A

What is a crane dynamometer

A crane dynamometer is a device used to measure the load or weight of an object being lifted by a crane. It consists of a hook, where the load is attached, and a load cell, which is the measuring element. A crane dynamometer, also known as a crane scale, is a crucial instrument used in various industries to enhance safety during lifting operations. It works by providing real-time feedback on the weight of the load, enabling operators to avoid overloading the crane. This helps prevent accidents, equipment damage, and injury. Crane dynamometers are widely used in construction, shipping, and manufacturing, where they provide accurate load measurements.

How does a crane dynamometer work

A electric crane scale works by utilizing a load cell to capture the weight of the lifted object. When a load is suspended from the scale, the load cell deforms slightly, converting the weight into measurable electrical energy. This information is processed and displayed on a screen to give the operator an accurate and instant reading of the load weight.

Can a crane dynamometer work in bad weather

Yes, some dynamometers are designed to work in adverse weather conditions. These usually contain internal waterproofing, weather-shielding, and corrosion-resistant materials.

How often should crane dynamometers be calibrated

At least once a year, dynamometers should be calibrated. More frequent calibration might be necessary in high-usage circumstances, such as construction or maritime operations, to guarantee the quality is still accurate.