Load carrying device with improved position control

Claim 1

In a vehicle having an elongated body with an engine space at a rear end thereof and an operator''s compartment forward of said engine space adjacent the front end thereof; ground engaging means on opposite sides of said body; a pair of fixed uprights adjacent opposite sides of said body and located rearwardly of said operator''s compartment; a pair of hollow lift arms, said lift arms having an elongated opening and having one end, which extends downwardly relative to the longitudinal axis of said lift arms, pivotally connected to respective uprights about a common horizontal pivot axis extending through said downwardly extending end at a location spaced above said body and below the longitudinal axis of the opening, said lift arms having elongated main portions extending forwardly above the body adjacent opposite sides of said body past said operator''s compartment and terminating in downwardly directed end portions adjacent the front end of said body; a material handling device pivotally connected to the free ends of said end portions; a first pair of extensible hydraulic rams, each having one end connected to one of said uprights and an opposite end connected to the associated lift arm to raise and lower said arms and device in response to extension and retraction of said rams; and pivot means cooperating on each of said lift arms for pivoting said device, said pivot means each comprising: a first unitary rigid link having one end pivotally connected to an upright above and rearwardly of said common pivot axis, said first link extending forward within the main portion of an associated hollow lift arm and terminating at its opposite end at the juncture between said main portion and said end portion; a second link directly pivotally connected to said opposite end of said first link, said second link extending downwardly within said downwardly directed end portion and pivoted about a fixed pivot axis in said hollow lift arm below said main portion, said lift arm having a forwardly directed opening adjacent said juncture with a projection from said second link extending forwardly through said opening; and an extensible and retractable tilt ram between said projection and said device for pivoting said device on said lift arms, said lift arms and links being constructed and arranged to allow unrestricted movement of said links within said lift arms while said lift arms are pivoted substantially 90* between raised and lowered positions on said uprights.