A plugging device which uses hydraulic and mechanical methods to lock onto the inner walls of tubing or casing so that expanding elements can seal off sections for downhole operations such as cementing, acidizing, or when producing formations need to be isolated.
Before the safety joint is unscrewed in the event the packer gets stuck, an attempt is made to free the packer. A pulling force is exerted on it by means of the hydraulic jar that is located above the safety joint.