Screw Jacks

A screw jack is a device for lifting loads, used in the automotive industry, warehouses, construction and repair work.

There are 4 types of jacks:

• Rack-and-pinion;
• Hydraulic;
• Pneumatic;
• Lever-screw;
• Diamond.

Design

By drive type, jacks are conditionally divided into 2 kinds:

1. Manually driven.
2. Electrically driven.

A mechanical hand jack is a reliable and durable mechanism that works by converting torque into linear motion. The design includes a worm gearbox and a screw-nut pair.

Torque is transmitted from the gearbox to the nut, creating linear motion and lifting the load. Modified versions also exist — a ball-screw drive supplemented with a roller design, which increases efficiency by minimizing resistance.

Diamond jacks

A diamond mechanical jack can lift a load of up to 2 t. It includes 4 arms on rotating hinges, positioned mutually perpendicular (at the corners of the diamond). Changing the angles changes the lifting height of the load or product.

The design can be powered by a manual or electric drive.

Bottle jack

This type of jack is distinguished by increased load capacity. Bottle jacks can lift loads of up to 5 tonnes, which is used in the repair of heavy vehicles. The massive design includes a thread with large elements that increase reliability.

Such jacks are effectively used in construction work.

Hydraulic screw jacks

Hydraulic models are widely used. In design, they are similar to traditional bottle jacks, but have a higher load capacity and construction weight. The strength and lifting capacity for a given load depend on the housing dimensions. The design of hydraulic jacks includes a valve that allows short-term operation at a load 25% above the maximum.

Pneumatic jack

Pneumatic jacks, used in vehicle repair, are also widely used. The design includes a pneumatic cushion, into which air is supplied from compressed gas cylinders. Industrial pneumatic jacks are used at large enterprises.

For private use, jacks inflated from a pump or from a vehicle’s exhaust system are common, providing a lift of vehicles to a height of at least 50 centimeters for undercarriage diagnostics or repair.