Machine element or mechanism – Control lever and linkage systems – Elements
Reexamination Certificate
1999-07-09
2001-10-02
Marmor, Charles A (Department: 3681)
Machine element or mechanism
Control lever and linkage systems
Elements
C074S491000
Reexamination Certificate
active
06295892
ABSTRACT:
BACKGROUND
The present invention relates to a lockable lever arm assembly for use with a mechanical leverage system mounted on a frame, such as the frame of a vehicle, to move an implement between a lowered position and a lifted position.
An implement is broadly defined as a tool or an instrument operatively connected to the frame of another object or structure, such as a vehicle. These implements are usually vertically movable between a lowered position and a lifted position. The lowered position generally corresponds to a ground-engaged position in the context of a vehicle.
The implements found on vehicles are typically used for cultivating, cutting grass or hay, plowing snow or earth, cleaning pavement, etc. Their size is generally proportional to that of the corresponding vehicle. Large implements require powerful lifting mechanisms provided with a hydraulic actuator. However, smaller implements may only require a lifting mechanism using the muscular force of the operator as the power source. Such implements are generally found on all-terrain vehicles (ATV) or garden tractors. Portable industrial devices may also be provided with a lifting mechanism of this kind. A lift handle is made accessible to the operator and the vertical position of the implement is changed by changing the position of the lift handle.
Conventional small lifting mechanisms have more or less complicated arrangements for maintaining an implement in the lifted position against its own weight. For instance, some use a toothed rack while others use a side locking pin that holds the lift handle in place. These locking mechanisms require that the operator pushes a button or moves the lift handle sidewards to lock it at or release it from its lifted position.
SUMMARY
It is an object of the present invention to provide a simple and efficient lockable lever arm assembly that, when used with a mechanical leverage system mounted on a frame, allows to easily move an implement between a lowered position and a lifted position. The movement is achieved by pivoting a lever arm in a single displacement plane, thus making it unnecessary to independently operate a locking mechanism or to move the lever arm sidewards for maintaining and releasing the implement.
More particularly, the present invention relates to a lockable lever arm assembly for use with a mechanical leverage system mounted on a frame to move an implement between a lowered position and a lifted position. The assembly comprises an elongated first lever arm pivotable in a first substantially vertical plane. The first lever arm has an upper end and a lower end. The lower end is pivotally connectable to the frame. A second lever arm is in motion-transmitting engagement with the lower end of the first lever arm. The second lever arm is movable in a second substantially vertical plane that is substantially parallel to the first plane. The second lever arm has an upper end and a lower end. The lower end of the second lever arm is pivotally connectable to the frame. Yet, the second lever arm is pivotable between a first limit position that corresponds to the lowered position of the implement, and a second limit position.
A detent member is further provided. The detent member is substantially coplanar with the second lever arm. It comprises an upper end that is pivotally connected to the frame, and a lower end that is in an interfering path with the upper end of the second lever arm. The lower end of the detent member is configured and shaped to receive and hold the upper end of the second lever arm in an intermediary position that is located between the first and second limit positions thereof. The intermediary position corresponds to the lifted position of the implement. At that point, an elastic stopper is slightly pressed by the second lever arm to maintain a firm contact between the second lever arm and the detent member.
In use, when the second lever arm is moved from its first limit position towards its second limit position, the lower end of the detent member holds the upper end of the second lever arm at the intermediary position to prevent it from returning to the first limit position until the detent member is released therefrom by pivoting the second lever arm from its intermediary position to its second limit position. This allows the second lever arm to be moved back to the first limit position. The elastic stopper is further pressed by the second lever arm when it reaches the second limit position.
It is also an object of the present invention to provide a lockable lever arm assembly comprising first means for providing a leverage; second means for providing an anchorage point, the second means being movable between a first limit position, corresponding to the lowered position of the implement, and a second limit position; third means for connecting the first means to the second means in a motion-transmitting engagement; fourth means for holding the second means in an intermediary position by its anchorage point when the second means is moved from its first limit position towards its second limit position, the intermediary position corresponding to the lifted position of the implement and being located between the first and second limit positions of the second means, the fourth means being disengageable by further moving the second means from its intermediary position to its second limit position so that the second means then be free to move from its second limit position to its first limit position; and fifth means for connecting the lever arm assembly to the mechanical leverage system.
It is further an object of the present invention to provide a method for manually changing the position of an implement movable between a lowered position and a lifted position with the use of a lockable lever arm assembly that is mechanically connected to a mechanical leverage system. The method comprises the steps of:
(A) pivoting an elongated first lever arm in a first direction to initiate a movement of the implement from the lowered position to the lifted position, the first lever arm being connected to a second lever arm that is then pivoted from a first limit position, corresponding to the lowered position of the implement, toward a second limit position thereof;
(B) continuing to pivot the first lever arm until the second lever arm is slightly pressing against an elastic stopper and be received in a detent member for holding it at an intermediary position, located between the first and second limit positions of the second lever arm, which intermediary position corresponds to the lifted position of the implement;
(C) stopping to pivot the first lever arm to allow the detent member to hold the second lever arm and keep the implement in the lifted position against its weight;
(D) pivoting again the first lever arm in the first direction to further compress the stopper and move the second lever arm toward the second limit position in view of moving the implement from the lifted position toward the lowered position;
(E) stopping to pivot the first lever arm when the second lever arm reaches its second limit position and where the detent member is released from the second lever arm;
(F) pivoting the first lever arm in a second direction, opposite the first direction, during which the second lever arm moves from its second limit position to its first limit position; and
(G) stopping to pivot the first lever arm when the second lever arm reaches its first limit position.
A non-restrictive description of a preferred embodiment will now be given with reference to the appended figures.
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Roy Normand
St-Pierre Yves
Bourque & Associates P.A.
Marmor Charles A
Pang Roger
Soucy International Inc.
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