Skruvjack

Skruvjack is a Swedish term that translates to "screw jack" in English. A screw jack is a type of mechanical jack that uses a screw mechanism to lift heavy objects. It is commonly used in automotive repair to lift vehicles for tire changes or other maintenance. The device consists of a threaded screw shaft that rotates within a threaded socket, causing the lifting saddle to move upwards or downwards.

There are several types of screw jacks, including the bottle jack, which is often used for automotive applications due to its compact size and portability. Another common type is the trunnion jack, which has a base that can be rotated to different angles, making it suitable for lifting loads that are not perfectly level. Other variations include the telescopic screw jack, which can achieve greater lifting heights, and the tripod screw jack, which provides a stable three-point base.

The operation of a screw jack relies on the principle of mechanical advantage provided by the screw thread. By applying torque to a handle or crank, a smaller input force can generate a much larger output force to lift the load. This makes them effective for lifting heavy objects with relative ease. However, screw jacks typically have a slower lifting speed compared to hydraulic jacks. Safety is a crucial consideration when using screw jacks, and users should always follow manufacturer instructions, ensure the jack is placed on a stable surface, and never work under a load supported only by a screw jack without additional safety measures like jack stands.