What Types Of Pneumatic Torque Tools Are There?

Types of Air Torque Tools

There are two types of pneumatic torque tools. The first has a relatively low torque output and is suitable for light joints and assemblies. These are not technically air torque wrenches, but are better known as "air screwdrivers". Pneumatic screwdrivers keep the drive shaft engaged at all times. When the specified torque limit is reached, the clutch disconnects power to prevent excessive torque. In a manufacturing environment where every product needs to be tightened to exact specifications, pneumatic screwdrivers do a great job - at least in light assemblies where torque values are relatively low and measured in inch-pounds rather than foot-pounds

Heavy-duty manufacturing environments require similar high-speed outputs, but with higher torque values. In these environments, the best pneumatic torque wrench for the job is actually an impulse tool. Like pneumatic screwdrivers, they provide steady torque control through a gear mechanism. However, they are capable of higher levels of torque—over 330 pound-feet, compared to about 95 pound-feet for air screwdrivers. If it weren't for the unique mechanism that helped give the pulse tool its name, it would be enough to cause an employee to be injured from a high-torque stop response.

Inside the Pulse, the tool is a hydraulic mechanism between the drive shaft and the air motor. This mechanism allows the tool's drive shaft to spin freely while the fastener is loose. As the fastener gets tighter, the hydraulic pressure in the mechanism increases until it acts on the inner anvil, creating a force. This force reduces the hydraulic pressure inside the mechanism, but it immediately begins to increase again. This is the pulse action named after the pulse tool.

Impulse is similar to the effect of an impact wrench in that it isolates the user from the kickback caused by high torque values. The difference is that the drive shaft is always engaged, allowing precise torque control. Impulse tools can automatically shut off when a specified torque value is reached, or allow the operator more control over overtightening. The best pneumatic torque wrench for manufacturing is one of those pulse tools or pneumatic screwdrivers that has the form and function to meet your tightening needs.