What Is an Electric Torque Spanner?
An electric torque spanner is a tool that uses an electric power source, such as a motor, to fasten bolts and nuts. It is sometimes also referred to as a ‘nutrunner’.
Electric torque spanners can tighten bolts and nuts to a specified torque at high speed by combining the functions of an electric socket spanner and a torque spanner. This tool significantly improves the efficiency of bolt and nut fastening operations.
There are electric torque spanners that perform from temporary tightening to final target conditions (tightening torque and angle of rotation), as well as models that allow for temporary electric tightening and final manual tightening. The latter are known as semi-automatic electric torque spanners, as they involve manual intervention.
Uses of Electric Torque Spanners
Electric torque spanners are used in fastening tasks involving a large number of bolts and nuts, where speed and high torque are crucial. For instance, the construction of large steel-framed buildings necessitates fastening numerous bolts.
These tools not only enhance work efficiency but also contribute to shorter construction periods. In high-altitude environments, such as in the construction of transmission line towers and wind turbines, electric torque spanners offer safety advantages, preventing accidents that can occur if an operator loses balance.
Designed for safety and efficiency, electric torque spanners include support mechanisms to counteract reaction forces and a design that minimizes operator stress. For high-torque applications, such as tightening 10-hole wheel nuts on large vehicles to the ISO standard of 600 N-m, electric torque spanners are the tool of choice.
For a three-axle vehicle, this means tightening 60 nuts across six wheels. Electric torque spanners excel in tasks requiring numerous high-torque fastenings.
Principle of Electric Torque Spanners
Electric torque spanners operate using an electric motor. They incorporate a reduction gear mechanism, often a planetary gearbox, enabling small motors to achieve high torques. Clutch mechanisms are used to reach a set torque, and angle detection mechanisms allow for precise angle-controlled operations.
Features of Electric Torque Spanners
Unlike impact spanners, electric torque spanners produce minimal noise, making them suitable for night-time or residential area use. Their low noise and vibration levels also reduce the risk of occupational accidents. These spanners not only lessen physical strain on operators but also lower the risk of conditions like hand-arm vibration syndrome and carpal tunnel syndrome, as well as noise-induced hearing loss.
Some models can connect to computers for managing and recording tightening data, such as ‘which bolts and nuts were tightened and at what torque’. This capability aids in preventing accidents due to untightened bolts and enables verification of work procedures.
While highly advantageous, these models inevitably increase in weight, especially those designed for large torques. When using larger electric torque spanners, the use of a spanner hanger with a damper is necessary for support, which can limit workspace and storage size.
Other Information on Electric Torque Spanners
1. Small Electric Torque Spanner
Small electric torque spanners, often handheld and battery-rechargeable, offer the advantage of cordless operation, allowing unrestricted work movement and placement.
These models can manage torque and maintain wireless communication capabilities for data transmission and control signal reception. This feature is also available in corded models, enabling centralized data management in factory settings.
2. Torque Management With Electric Torque Spanners
Electric torque spanners monitor torque and changes in angle and speed during tightening. Work records can be stored in the tool itself or wirelessly transmitted to a host for assembly result data management. These functions enable accurate determination of whether bolts are properly tightened. Issues such as diagonal tightening, and omitted or double washer insertions can be identified from torque data.
Advanced models can detect the spanner’s posture and position, assessing the fastening hole’s location to ensure correct bolt or nut tightening. They can also automatically adjust tightening torque based on the bolt or nut specifications and working position.