Material or article handling – Vertically swinging load support – Shovel or fork type
Reexamination Certificate
2001-11-01
2004-02-24
Underwood, Donald W. (Department: 3652)
Material or article handling
Vertically swinging load support
Shovel or fork type
C414S685000
Reexamination Certificate
active
06695568
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a small loader that is manually operated by a standing operator at the rear of the loader. The loader has a low lift arm profile, so that an operator standing at the rear of the loader can see the work area. The low profile lift arms aid side-to-side visibility.
Various small self-propelled loaders have been advanced, where an operator will either stand or walk on the ground behind the loader or stand on a platform on the loader frame to manipulate the work element that is attached to the forward ends of pivoting lift arms.
These loaders find utility in small load applications, where loads that are too heavy for a person to lift can be hoisted. The ability of the loaders to be operated in small areas is important. Ease of manipulation of the bucket or work tool, as well as the ability to see the work that is being carried out is also important.
While it is desirable to have the pivot points for the boom near the rear of the small loader, and relatively high so that the reach is adequate for operation, conventional, straight lift arms tend to block vision to the side, as they are raised. Additionally, they will be in the way for access from the side of the loader to components such as the engine or drive components that are nested between the lift arms.
SUMMARY OF THE INVENTION
The present invention relates to a small self-propelled loader that is designed for operation by an operator standing at the rear of the loader, and which has forwardly extending lift arms that have center portions that are formed downwardly to have side portions at a low level, closely adjacent to the top of the components that are used for driving. The dropped or lowered side portions permit easy access to the center of the machine frame when the arms are lowered, and also keeps a low profile of the side portions of the arms they raise to insure good side-to-side visibility for the operator.
The lift arms are pivoted at the uppermost, rear portion of the frame, and extend forwardly to support a bucket, or other work implement at the forward ends of the arms. Hydraulic actuators are utilized for raising and lowering the lift arms, in a normal manner.
The far rear pivot of the lift arms permits using a longer arm on the same length machine. This increases the lift capacity for the same size actuator and there is a longer arc of movement. This means that the bucket or tool moves more vertically as it initially raises, rather that having a pronounced arcuate path that causes the bucket to move forward a significant amount as it starts to lift.
The lift arms taper downwardly from the pivot points to a position along the sides of the machine, and in the form shown extend forwardly substantially parallel to the top lengths of the tracks used for driving the machine. The forward ends of the lift arms then are recessed on the lower side so that they curve downwardly around the rounded forward ends of the tracks, where the tracks go over a front sprocket or guide wheel. When in a lowered position, the forward ends of the lift arms will support a bucket on the ground or support surface over which the tracks are moving.
Controls for the lift arms are all at the rear of the machine, and accessible by an operator standing on the ground or standing on a support platform at the rear of the machine. The lift arm pivots are generally a little higher than waist high on an operator, so that the operator can see over the highest portions of the machine, for visibility. The operating control levers are just to the rear of the pivots for accessibility of the operator.
The lift arms are made into a rigid lift arm assembly with a cross member at the front end of the lift arms that also supports an upright strut for mounting a cylinder or actuator that is used for tilting the bucket or work implement.
The low profile lift arms thus provide an adequate lift reach or height, and are dropped in the center portions for accessibility to components and also for side to side visibility.
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Bares Mark F.
Page James H.
Clark Equipment Company
Underwood Donald W.
Westman Champlin & Kelly P.A.
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