Electric transportation cart with adjustable deck

1. An electric transportation cart comprising:

a deck having a deck front portion and a deck rear portion, the deck rear portion including two first rails which are located on two sides of the deck, a first opening defined through a bottom wall of the two sides of the deck and communicating with the first rail corresponding thereto;

a base being a rectangular frame and having multiple casters connected to an underside thereof, the base having a base front portion and a base rear portion which includes two second rails, the two second rails located on two sides of the base, a second opening defined through a top wall of the two sides of the base and communicating with the second rail corresponding thereto, a handle connected to one end of the base and a switch unit connected to the handle;

a first bar slidably connected between the two first rails;

a first link assembly and a second link assembly pivotably connected between the deck and the base, the first link assembly including a first link and a second link, the second link assembly including a third link and a fourth link, the first and second links located on a first side of the cart and pivotably connected to each other at a first pivotal portion, the third and fourth links located on a second side of the cart and pivotably connected to each other at a second pivotal portion, the first link defining a section that is located below the first pivotal portion as a first lower section, the third link defining a section that is located below the second pivotal portion as a second lower section, the first and second lower sections each having an extension link extending toward the base, a second bar connected between the two respective extension links, the first link assembly installed to the first rails via the first opening defined through the bottom wall of the two sides of the deck, the second link assembly installed to the second rails via the second opening defined through the top wall of the two sides of the base;

two opposite ends of the first link respectively connected to one of two ends of the first bar and a roller slidably in one of the two second rails, two opposite ends of the third link respectively connected to another one of the two ends of the first bar and another roller slidably in another one of the two second rails, the second link and the fourth link each being connected between the base front portion and the first bar, when the deck is located at a lowest position, the extension links and the second bar extend below the base;

a hydraulic cylinder connected between the first bar and the second bar, the hydraulic cylinder connected to a pump that is connected to the base, wherein when the deck is located at the lowest position a length of the hydraulic cylinder is at a minimum and the extension links and the second bar extend below the base;

a control unit connected to the base and including a power source and a circuit board, the switch unit, the power source and the pump electrically connected to the circuit board, and

the pump being activated by operating the control unit to extend or retract the hydraulic cylinder so as to activate the first and second link assemblies to move the deck up and down relative to the base.

2. The electric transportation cart as claimed in claim 1 , wherein the control unit is connected to the base and includes a wireless signal receiver which is electrically connected with the circuit board, a remote control sends commands to the control unit, the wireless signal receiver receives the commands from the remote control to control the deck to move up and down.