Heavy duty jack

Claim 1

IN A HEAVY DUTY JACK OF THE CHARACTER DESCRIBED, THE COMBINATION OF: A PORTABLE BASE HAVING TWO UPWARDLY EXTENDING PARALLEL GUIDE MEMBERS RIGIDLY SECURED THERETO; AN UPRIGHT POWER CYLINDER MOUNTED N THE BASE; A PISTON IN THE CYLINDER WITH A PISTON ROD EXTENDING THEREFROM UPWARD FROM THE CYLINDER; A CARRIAGE SUSPENDED FROM THE UPPER END OF SAID PISTON ROD AND HAVING TWO INTERCONNECTED SIDE PLATES STRADDLING SAID TWO GUIDE MEMBERS; AN UPPER REARWARDLY LOCATED SLEEVE WELDED TO THE OUTER SIDE OF EACH OF SAID PLATESA PERPENDICULARLY THEREOF; AN UPPER SPINDLE MOUNTED IN EACH OF SAID SLEEVES AND EXTENDING THROUGHT THE SIDE PLATE INWARDLY FROM THE SIDE PLATE; AN UPPER ROLLER MOUNTED ON EACH OF SAID SPINDLES ON THE INNER SIDE OF THE SIDE PLATE IN ROLLING CONTACT WITH THE REAR SURFACE OF THE CORRESPONDING GUIDE MEMBER; FIG-01 A LOWER FORWARDLY LOCATED SLEEVE WELDED TO THE OUTER SIDE OF EACH OF SAID SIDE PLATES PERPENDICULARLY THEREOF; A LOWER SPINDLE MOUNTED IN EACH OF SAID LOWER SLEEVES AND EXTENDING THROUGH THE SIDE PLATE INWARDLY FROM THE SIDE PLATE; A LOWER ROLLER MOUNTED ON EACH OF SAID LOWER SPINDLES ON THE INNER SIDE OF THE PLATE IN ROLLING CONTACT WITH THE FRONT SURFACE OF THE CORRESPONDING GUIDE MEMBER; AND A REINFORCEMENT MEMBER ON THE OUTER SURFACE OF EACH SIDE PLATE UNITED WITH THE TWO SLEEVES ON THE SIDE PLATE INTERCONNECTING THE TWO SLEEVES IN TENSION.