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A person expertly uses the Evolution hydraulischer Drehmomentschrauber von Plarad on industrial machinery, showcasing innovation in heavy industry.

The evolution of hydraulic torque wrenches by PLARAD (Part 1.1)

Milestones in bolting technology: Innovations since the 1970s

 

Are you familiar with the history of the hydraulic torque wrenches by PLARAD? It’s an impressive story of how technical tools have been continuously developed through innovation. In the first part of this blog series, we take a look at the beginnings and development of hydraulic torque wrenches, which Plarad has been producing since the 1970s and which still play a key role in industries such as mechanical engineering, wind energy, and heavy industry.

 

HP-S (from 1970): The start of a revolution

In the 1970s, Plarad launched the HP-S, a hydraulic torque nutrunner that revolutionized the bolting industry. Its robust steel-welded construction, an impressive torque range of up to 30,000 Nm, and an operating pressure of 350 bar made it an indispensable tool for demanding applications. The integrated ratchet prevented unintentional reverse rotation, increasing safety. The HP-S set the standard for modern hydraulic torque wrenches in heavy industry, where high torques were required to securely fasten large bolted joints.

 

HP-A (1978-1985): Enhanced precision with rotational angle scale

In 1978, Plarad introduced the HP-A, which offered improved precision and safety in bolting through the addition of a rotational angle scale and an oscillating cylinder with valve technology. With an expanded torque range of up to 40,000 Nm, the HP-A quickly became the preferred tool in the construction and mechanical engineering industries.

 

HLS/L (1985-1990): Higher operating pressure for new applications

The HLS/L model increased the operating pressure to 700 bar, enabling more compact tools and extending the torque range to 40,000 Nm. As a predecessor to today’s LT bolt, the HLS/L found wide application in the petrochemical and shipbuilding industries.

 

HDS (from 1980): An innovative attempt

The HDS was the first torque wrench with a hydraulic motor and offered remote control via a directional valve as well as hand and foot controls. With a torque of up to 3,000 Nm and an operating pressure of 80 to 130 bar, it marked an important step forward in development, although its heavy weight limited its use.

 

A look ahead to the next development

Stay tuned for the next developments that Plarad has achieved in the field of hydraulic torque nutrunners. In the next part, we’ll explore how advanced technological generations continue to deliver high torques for large bolted connections and meet the growing demands of the industry.