According to the way of operation there are two types of jacks:
Jacks are operated with separate hydraulic hand pump or power pack unit. The pressurized oil is transferred by the means of hose pipes. They are suitable for constrained spaces or to be operated directly under the load. These type of jacks are most suitable for lifting heavy loads.
Integral (Bottle Type):
Popularly known as bottle type jacks, the oil pump is inbuilt feature of these jacks. No separate pump or power pack unit is required to operate the jack. These jacks are suitable for applying the force. The ram of integral jack may be plain or screwed.
The ram of the jack are either plain or screwed type for heavy loads.
Screwed Ram Jack
The ram is threaded and provided with safety lock nut. The lock nut is also threaded internally to match the ram. Once the load is lifted the lock nut is rotated over the ram and locked against the body. The benefit of this type of jack is that load is sustained by hydraulic pressure and mechanically by lock nut. Even if the hydraulics fails, the lock nut supports the load mechanically, thus maintaining the constant load.
Plain Ram Jack
The ram of these jacks are kept a plain diameter. They are generally used for low to medium type of loading.
A type of plain ram jack. They feature very less stroke (Lift) and Low collapsed height. They are used only for pressing operations. Multiple numbers of jacks are used for an operation.
Hollow Ram Jacks:
A plain ram jack wherein the ram has through bore to pass a stud. They generally used for tightening purposes.
They are basically a plain ram jack with toe arrangement. They generally used for lifting load with very low clearance and also with high clearance.
Multi-Stage Jack (Special Purpose)
Multiple jacks are enclosed in telescopic fashion and come out one after the other as pressurized oil is supplied. These jacks are special purpose jacks used when the forces is to be applied over long distance. Again the ram may be either plain or screwed depending up on the criticality of the operation.