Definition
A disc push-pull force gauge is a mechanical testing instrument used to measure thrust and pull forces under static or quasi-static conditions. Its core feature is the use of disc-shaped force sensors as force value sensing elements, which are usually integrated with digital displays or data acquisition systems to achieve quantitative evaluation of the force in the push and pull direction. This instrument is not a dynamic impact force measurement device, and its measurement process is usually carried out at a slow, steady rate.
Principle
The working principle of the disc push-pull force gauge is based on Hooke's law and strain effects. When an external force acts on a disc sensor, the elastomer inside the sensor, usually made of metal, undergoes a small deformation. The resistance of the strain gauge attached to the sensitive area of the elastomer changes as a result, thus disrupting the balance of the Wheatstone bridge and generating an electrical signal proportional to the external force. The signal is processed by an amplifier and analog-to-digital converter inside the instrument, and finally displayed or output in force units (e.g., Newton, kilogram force). Its basic physical relationship can be expressed as:F = k · Δx, where F is the force, k is the elastic coefficient of the sensor, and Δx is the elastic deformation. In terms of electrical output, the relationship between output voltage U and force F can be approximated as:U ≈ S · F, S is the sensitivity coefficient of the sensor.
Measurement method
When measuring with a disc push-pull force gauge, follow a prescriptive process to ensure data reliability. First, select an instrument with a suitable range according to the estimated force value, and perform preheating and clearing operations. The instrument is securely mounted on the test platform or mechanical structure by means of an adaptation fixture to ensure that the force axis coincides with the center axis of the sensor to reduce the error of lateral force introduction. When applying a load, the rate should be controlled to remain smooth and uniform to avoid sudden shocks. Record the data after the readings are stable. For tests that require peak hold, enable the peak hold function of the instrument. After the measurement, the load should be unloaded and the instrument returned to zero. Averaging multiple measurements can help improve the representativeness of the results.
Influencing factors
The accuracy of the measurement results is influenced by several factors. Changes in ambient temperature may cause drift between the elastic modulus of the sensor and the sensitivity coefficient of strain gauges, and some instruments have temperature compensation functions to alleviate this problem. Coaxiality deviations in the direction of force application can result in lower measurements than actual axial forces and may reduce sensor life. Excessive loading rates can introduce dynamic errors due to inertia effects, beyond the quasi-static measurement range of the instrument design. The accuracy and resolution of the instrument itself, as well as the mechanical fatigue and creep that may occur over time, are also factors to consider. In addition, electromagnetic interference and power supply voltage fluctuations in the connecting cables may also affect the stability of the electronic measurement unit.
Applications
Disc push-pull force gauges are widely used in industrial research and development and quality control. In the electronics manufacturing industry, it is commonly used to measure the haptic force and reset force of key switches, connector plugging and unplugging, and micro switches. In the field of automotive parts, it is used to test the operating force of operating parts such as window rockers, handles, and pedals. In the packaging industry, it is used to evaluate the opening force of bottle caps and the peeling force of seals. In materials research, it can be used to evaluate the bond strength of materials or the assembly force of tiny components. In the textile industry, it can be used to measure the sliding resistance of zippers and fasteners. Its portable design is also suitable for force calibration in field installation and maintenance.
Selection considerations
When choosing a disc push and pull force timer, it is necessary to comprehensively consider a number of technical parameters and usage conditions. The range should cover the expected maximum force value with a certain margin, and usually choose a model that keeps the conventional measurement value within 20% to 80% of the range. The accuracy level must meet the requirements of the test standard or quality control document. The instrument interface type (e.g., USB, RS232) needs to be compatible with the data logging system. Consider the site environment and choose an enclosure with the appropriate protection level. For mobile measurements, the size, weight, and power supply method (e.g., battery life) of the instrument are important factors. In addition, whether additional functions such as peak hold, unit switching, zeroing, and alarm are required should also be determined according to specific testing needs. It is recommended to refer to the requirements of national metrology verification regulations or international standards (such as ISO 7500-1) for force measurement equipment.