Patent ID: 7780395

Claim:
A lift arm and a skid-steer loader comprising: a pair of right and left first arm portions disposed in a vehicle width direction of a loader main body, and a pair of right and left second arm portions disposed on front end sides of the first arm portions; proximal end sides of the respective first arm portions rotatably supported by a rear portion of the loader main body and the front end sides of the respective first arm portions disposed extendedly from the rear portion of the loader main body toward a front side through a side portion of the loader main body; plate-shaped reinforcing bodies respectively attached to an outside surface and an inside surface of each of the first arm portions from a central portion to the front end side thereof; proximal end sides of the second arm portions respectively disposed on the front end sides of the first arm portions, front end sides of the second arm portions respectively disposed extendedly so as to direct downwardly on a front side of the loader main body from the front end sides of the respective first arm portions; and a beam portion disposed between proximal ends and the front end sides of the respective second arm portions for coupling and reinforcing the pair of right and left second arm portions, wherein each of the first arm portions comprises a sheet metal material having a lateral sectional shape formed to a hollow rectangular shape; each of the second arm portions comprises a flat sheet metal material; the proximal end side of each of the second arm portions is attached to an inside surface side of each of the first arm portions, respectively; a lower surface side portion on the front end side of each of the first arm portions is coupled with an outside surface side portion on the proximal end side of each of the second arm portions through a reinforcing member; the plate-shaped reinforcing bodies comprise cylinder attachment portions for supporting front end sides of arm cylinders for rotating the first arm portions; the second arm portions comprise attachment mounting portions disposed to the front end sides thereof for rotatably supporting a work attachment; and actuator attachment portions are constituted on front end sides of the plate-shaped reinforcing bodies to support proximal ends of actuators for operating the work attachment.