Motorized screw jack assembly

A jack assembly comprising:

• a pair of wall members fixed together in parallel with each other and each including two horizontal grooves and a vertical groove arranged between said horizontal grooves;
• a pair of frames including a middle portion pivotally coupled together at a shaft, said shaft including two ends slidably engaged in said vertical grooves of said wall members, said pair of frames including two lower ends and two upper ends, two blocks pivotally secured to said lower ends of said pair of beams at two axles, a first axle of said two axles including end portions slidably engaged in said horizontal grooves;
• a bolt engaged through said blocks;
• a bracket;
• a pair of arms including lower ends pivotally coupled to said upper ends of said frames and upper ends pivotally coupled to said bracket;
• and
• means for actuating said bolt so as to move said blocks toward each other or away from each other in order to move said bracket upward or downward, said actuating means including a housing, a motor disposed in said housing, engaging means for engaging with said bolt, and gearing means coupling said motor to said engaging means so as to rotate said bolt;
• said gearing means including a first gear secured to said motor, a sleeve fixed in said housing and having a first internal gear formed therein, at least one first disc having at least one first pinion rotatably engaged thereon, said first pinion being engaged with said first gear and engaged with said first internal gear, a second gear secured to said first disc, a second disc including at least one second pinion rotatably engaged thereon, said second pinion being engaged with said second gear and engaged with said first internal gear, said second disc including a second internal gear formed therein;
• said engaging means including a third gear engaged with said second internal gear, and a head having an engaging surface formed therein for engaging with said bolt.