Lift boom assembly for a loader machine

A lift boom assembly mounted on a machine having a fore-and-aft extending frame, comprising:

• a pair of supports for supporting the boom assembly, said supports being disposed toward a rear of the frame;
• a lift assembly having a pair of lift arms arranged on opposite lateral sides of the frame, each lift arm having a forward end to which a working tool is mounted and comprises a main lift link and a second lift link pivotally connected to each other, said main lift link extending rearwardly from a forward portion of the frame and including at a rear end thereof upper and lower connecting portions, said second lift link having a first end pivotally connected to the upper connecting portion of the main lift link and a second end pivotally connected to one of said supports;
• a pair of extendable and retractable drivers arranged on opposite sides of the frame and connected between the frame and a respective lift arm for effecting powered vertical movements of the lift assembly and the tool carried thereby relative to the frame;
• and
• a pair of control arms, each control arm having a first end pivotally connected to the frame adjacent the rear end thereof and having a second end which, when the boom assembly is in a lowered position, extends upwardly and rearwardly from the first end and is pivotally connected to said lower connecting portion of a respective main lift link, and wherein the first end of each driver and the first end of each control are connected to the frame at a common location.

A lift boom assembly for vertically moving a working tool carried by said boom assembly between lowered and raised positions along a substantially vertical path, said boom assembly being mounted to a machine having a fore-and-aft extending mobile frame, said lift boom assembly comprising:

• a pair of supports for supporting the boom assembly, said supports being disposed toward a rear of the frame and on each side thereof, and wherein each support extends upwardly from and terminates at an upper end located substantially above a support surface for said frame;
• a lift assembly having a pair of lift arms arranged on opposite sides of the frame, each of said lift arms having a forward end to which said working tool is mounted and comprising a main lift link and a second lift link pivotally connected to each other, said main lift link extending rearwardly from a forward portion of the frame and including at a rear end thereof upper and lower connecting portions, said second lift link having a first end pivotally connected to the upper connecting portion of the main lift link and a second end pivotally connected to the upper end of one of said supports;
• a pair of extendable and retractable drivers arranged on opposite lateral sides of the frame and connected between the frame and a respective lift am for effecting powered vertical movements of the lift assembly relative to the frame;
• and
• a pair of control arms, each control arm having a first end pivotally connected to the rear end of the frame and having a second end disposed above said first end and that is pivotally connected to the lower connecting portion of a respective main lift link such that the control link swings forwardly and rearwardly of its true vertical position to control movements of the lift assembly in response to vertical movement of the boom assembly between raised and lowered positions.

A lift boom assembly mounted on a machine having a fore-and-aft extending frame supported for movement by a front pair of wheels mounted on a front axle and a rear pair of wheels mounted on a rear axle, said lift boom assembly comprising:

• a pair of supports for supporting the boom assembly, said supports being disposed toward a rear of the frame;
• a lift assembly having a pair of lift arms arranged on opposite lateral sides of the frame, each of said lift arms having a forward end to which a working tool is mounted and comprises, in combination, a main lift link and a second lift link, said main lift link extending rearwardly from a forward portion of the frame and including at a rear end thereof first and second connecting portions, said second lift link having a first end connected at a first pivotal connection to the first connecting portion of a respective main lift link and a lower second end connected at a second pivot connection to one of said supports;
• a pair of extendable and retractable drivers arranged on opposite sides of the frame and connected between the frame and a respective lift arm for effecting powered vertical movements of the lift assembly and tool relative to the frame;
• and
• a pair of control arms, each control arm having a first end connected at a third pivot connection to the second connecting portion of a respective main lift link and a lower second end connected at a fourth pivotal connection to the frame of the machine, and wherein the first, second, third and fourth pivotal connections defined by each lift arm and control arm combination are all rearward of the rear axle of the machine.

A lift boom assembly mounted on a self-propelled skid steer loader having a fore-and-aft extending frame that is supported by a pair of front and a pair of rear wheels, each pair of wheels being rotatable about a fixed laterally extending axis, said frame having boom supports attached to a rear thereof, a lift assembly comprising a pair of lift arms arranged on opposite sides of the frame and which are operably coupled to each other, each lift arm having a forward end to which a working tool is articulately mounted and a rear end, said pair of lift arms each comprising an elongated main lift link and a shorter second lift link that are pivotally interconnected to each other, each main lift link extending rearwardly from a forward portion of the frame and includes, at a rear end thereof, upper and lower rigidly joined connecting portions, said second lift link having a first end pivotally connected to the upper connecting portion of the main lift link and a second end pivotally connected to an upper end of the respective boom support at a location substantially above a support surface of the frame rearwardly of and vertically between the upper and lower connecting portions of the respective main lift link when the boom assembly is in a lowered position relative to the frame, a pair of extendable/retractable drivers arranged on opposite sides of and interconnected between the frame and said lift arms for effecting powered elevational movements of the boom assembly relative to the frame, and a pair of control arms, each control arm having a first end pivotally connected to the frame rearwardly of the rear wheel axis and having a second end which, when the boom assembly is in a lowered position, extends upwardly and rearwardly from the first end and is pivotally connected to the lower connecting portion of a respective main lift link, and whereby the pivotal connection between the control arm and the main lift link of each lift arm moves along an arc as the lift arm assembly is raised by the powered drivers and the pivot between each main lift link and second link moves in a controlled path that effectively extends and retracts the effective length of the main lift arm links of each lift arm such that the tool carried at the forward end of the boom assembly moves along a substantially vertical path between lowered and raised positions thereof.