Small size crane having a hydraulically operated jib and an electromotor-driven hydraulic pump

Claim 1

A crane comprising a crane post formed with two spaced-apart sidewall portions along a major part of its height; a vertically swingable jib having its inner end portion hingedly connected to the top of the crane post and extending away therefrom when in operative position; hydraulic jack means to effect vertical swinging movement of the jib and including a cylinder having its rear end hingedly connected to the lower end portion of the crane post between said two spaced apart sidewall portions thereof, said cylinder having a diameter less than the space between said sidewall portions to permit said cylinder to swing between said sidewall portions, and a ram extending from said cylinder and having its outer end hingedly connected to the jib in a manner causing said cylinder and ram to occupy a forwardly inclined position when the jib is in operative position; an oil reservoir mounted on said cylinder; an oil pump for delivering oil under pressure from said reservoir; actuatable valve means mounted on said cylinder for controlling the flow of oil from said pump into said cylinder and from said cylinder back to the reservoir, respectively; and an electric motor operable to drive said oil pump; said electric motor and oil pump being both mounted, one above the other, on the rear side of said cylinder facing away from the outer end of the jib and being of a combined length no greater than the length of said cylinder, each having a diameter substantially equal to the diameter of said cylinder, such that said electric motor and pump swing with said cylinder between said sidewall portions during the raising and lowering of the jib and said electric motor and pump are disposed to be substantially sheltered between said spaced-apart sidewall portions of the crane post when the jib is in operative position.