Hydraulic Jacks

A hydraulic jack is a stationary or mobile device for moving loads along a vertical plane. Pressure in the system is created by a working fluid: oils with increased hygroscopicity are used, which ensures uniform pressure across the entire surface area. Hydraulic jacks have the highest load capacity among devices of this type.

Design

The simplified design of a hydraulic jack includes 2 elements:

• Plunger;
• Working cylinder.

Operating principle: pressure is pumped by a special fluid supply system into a small cylinder, then transferred to a large one. This increases the pressure on the plunger and causes its vertical displacement. This is how loads over 3 t are lifted without applying effort.

The complete design of a hydraulic jack consists of:

1. A piston drive, containing hydraulic oil and a device for increasing pressure. The drive can be electric or mechanical.
2. A pressure distribution device, which directs the fluid outlet in a specific direction.
3. A fluid filter. Cleans the oil of abrasives and contaminants to prevent damage to internal parts.
4. A regulator. Required for supplying the needed pressure level. Includes a relief valve for returning the plunger to its initial position.
5. A pump for supplying the hydraulic medium.

The load capacity of hydraulic jacks can reach 1000 tons.

Classification of hydraulic jacks

There are several types of hydraulic jacks — specialized or universal:

• Bottle jacks. Include a ram and an oil supply system.
• Telescopic jacks. A piston is used instead of a ram. Lift height is twice that of standard types.
• Scissor (diamond-type) jacks. Used for lifting vehicles. Have several application points.
• Trolley jacks. Specialized for repairing vehicles and equipment. Lift height is low.
• Double-ram jacks. Have a paired piston for increased load capacity.