Power control apparatus

Abstract

Disclosed herein is a power control apparatus. A piston partitions a hydraulic chamber of a cylinder body unit into a first hydraulic chamber and a second hydraulic chamber. A screw shaft unit passes through the piston and is threadedly coupled to the piston. The first hydraulic chamber and the second hydraulic chamber are directly connected to each other by a single hydraulic chamber connection pipe. A valve unit is provided on the hydraulic chamber connection pipe. Force of rotating the screw shaft unit, required to move the piston, is controlled by adjusting the degree of opening of the hydraulic chamber connection pipe.

What is claimed is: 
     
         1 . A power control apparatus, comprising:
 a cylinder body unit defining a hydraulic chamber therein;   a piston moving along an inner surface of the hydraulic chamber of the cylinder body unit, the piston partitioning the hydraulic chamber into a first hydraulic chamber and a second hydraulic chamber;   a screw shaft unit rotatably disposed in the hydraulic chamber of the cylinder body unit, the screw shaft unit passing through the piston and being threadedly coupled to the piston;   a hydraulic chamber connection pipe connecting the first hydraulic chamber to the second hydraulic chamber that is partitioned from the first hydraulic chamber by the piston; and   a valve unit provided on the hydraulic chamber connection pipe, the valve unit controlling opening of a passage of the hydraulic chamber connection pipe.   
     
     
         2 . The power control apparatus as set forth in  claim 1 , wherein a rate of change in volume of the first hydraulic chamber in response to movement of the piston is equal to a rate of change in volume of the second hydraulic chamber. 
     
     
         3 . The power control apparatus as set forth in  claim 1 , wherein extension shafts protrude from respective opposite ends of the screw shaft unit and are rotatably coupled to the cylinder body unit, one of the extension shafts protruding out of the cylinder body unit,
 the power control apparatus further comprising a power transmission unit connected to one of the extension shafts of the screw shaft unit.   
     
     
         4 . The power control apparatus as set forth in  claim 3 , wherein the power transmission unit comprises:
 a rotating gear coupled to the corresponding extension shaft; and   a plurality of transmission gears engaging with the rotating gear to transmit an operating force of an exerciser to the rotating gear.   
     
     
         5 . The power control apparatus as set forth in  claim 4 , wherein the power transmission unit further comprises
 a clutch unit selectively engaging the transmission gears with each other so that the operating force of the exerciser can be controlled in steps.   
     
     
         6 . The power control apparatus as set forth in  claim 1 , further comprising
 a guide bar disposed in the hydraulic chamber in a direction in which the piston moves, the guide bar passing through the piston and guiding linear movement of the piston.   
     
     
         7 . The power control apparatus as set forth in  claim 1 , further comprising
 a control unit controlling a degree of opening of the valve unit, the control unit comprising:   a controller connected to the valve unit, the controller controlling operation of the valve unit;   an operation panel connected to the controller;   a first hydraulic sensor connected to the controller, the first hydraulic sensor measuring a hydraulic pressure in the first hydraulic chamber; and   a second hydraulic sensor connected to the controller, the second hydraulic sensor measuring a hydraulic pressure in the second hydraulic chamber.   
     
     
         8 . The power control apparatus as set forth in  claim 1 , wherein the piston has a hydraulic chamber connection hole therein, the hydraulic chamber connection hole communicating the first hydraulic chamber with the second hydraulic chamber,
 the power control apparatus further comprising a valve diaphragm closing the hydraulic chamber connection hole when the piston moves in one direction and opening the hydraulic chamber connection hole when the piston moves in the other direction.   
     
     
         9 . The power control apparatus as set forth in  claim 8 , wherein the valve diaphragm comprises a plate spring having a predetermined elasticity. 
     
     
         10 . The power control apparatus as set forth in  claim 1 , further comprising:
 an auxiliary connection pipe connecting the first hydraulic chamber to the second hydraulic chamber; and   a check valve provided on the auxiliary connection pipe, the check valve controlling flow of fluid such that the fluid flows through the auxiliary connection pipe only in one direction.