How to Select Lifting JacksHow to Select Lifting JacksHow to Select Lifting Jacks

Image Credit: Venture Mfg. Co.|Zhuhai Greatway Automobile Equipment|Norco Lifting Equipment

 

Lifting jacks are used for leveling or positioning heavy equipment, or for supporting structures. They use screw or cylinder-based actuators and are powered by hydraulic, mechanical, electric, or manual methods. Typically, the lifting element is described as either a shoe or a saddle.

 

Types of Lifting Jacks

 

Many different types of lifting jacks are available.

 

  • Bottle jacks use a hydraulic cylinder for lifting and are often hand-pumped. The workpiece is engaged and lifted by a saddle at the end of the cylinder.
  • Inflatable jacks involve a bag that is placed under the workpiece and inflated.
  • Ratchet jacks have a manual crank and ratchet-and-pawl design.
  • Scissor jacks use linked, folding support members that are drawn together.
  • Screw Jacks are devices which use the mechanical advantage of threads to lift the workpiece. Jacking may involve spinning a nut to drive a screw or worm gear drive. Most screw jacks fall into one of two categories:
    • Ball screw jacks use recirculating ball bearings on a precision pitch screw for fast, efficient lifting. They require relatively little drive effort.

    • Machine screw jacks use screws with less pitch, and usually do not have ball bearings. They are somewhat less efficient and require more effort than ball screw jacks; however, they can better resist back driving and vibration than other types of lifting jacks.

  • Service jacks or floor jacks are designed to get under loads such as vehicles. They often have a relatively long reach.
  • Toe jacks use a lift toe or are shoe-mounted to stay near the floor in the retracted position. They can fit under a workpiece with little ground clearance.
  • Transmission jacks are designed for lifting, removing, and installing transmissions or engines from vehicles. These lifting jacks usually have several saddles or lift points and a wide base for stability.

 

Specifications

 

There are several product specifications to consider for lifting jacks.

 

  • Lift capacity is the maximum lift force.
  • Lift stroke is the difference between the fully-retracted and full-extended positions of the lifting jack.
  • Minimum height is the distance from the jack base to the lifting element in the fully-retracted position.
  • Maximum height is the distance from the jack base to the lifting element in the fully-extended position.

 

Standards

 

BS EN 1494 - MOBILE OR MOVABLE JACKS AND ASSOCIATED LIFTING EQUIPMENT