Machine element or mechanism – Control lever and linkage systems – Multiple controlled elements
Reexamination Certificate
2000-01-06
2001-06-19
Marmor, Charles A (Department: 3681)
Machine element or mechanism
Control lever and linkage systems
Multiple controlled elements
C074S473330, C074S473300
Reexamination Certificate
active
06247378
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an operator control device for an infinitely variable transmission and in particular to a control device having a control lever that is movable between a minimum speed position and maximum speed positions and which has an intermediate set point position for which the operator can adjust a speed to be commanded when the lever is in the set point position.
2. Description of the Related Art
An infinitely variable transmission (IVT) has potential to provide a large range of speeds to a self-propelled work machine such as a construction machine, tractor, agricultural combine, cotton picker, forage harvester, etc. One benefit of an IVT is that it gives the operator the ability to select the speed that best matches the present task. The control device for the IVT needs to provide the operator with a means to adjust this speed. Currently available IVT control devices provide the operator with the ability to choose the desired speed. The means to choose the desired speed have been accomplished by various executions of two basic concepts. One concept provides a lever or similar device that is moved through a pattern to a position that corresponds to the desired speed. If a lever with good speed resolution is provided, i.e. the ability to make fine adjustments of the speed, the amount of lever travel will exceed the range of convenient reach for the operator. Likewise, a lever that is compact and convenient to reach does not provide sufficient speed resolution.
The other control concept provides a lever or similar device that only selects a travel direction based on the lever position, and by an alternate motion, incrementally increases or decreases the speed. For example, a lever that moves fore and aft to select the desired travel direction may also pivot left and right to increase and decrease speed respectively. The lever position only indicates travel direction but not the actual speed. The advantage of this concept is that the lever takes less space on the control console since it does not require a position for each speed. The lever is easy to reach for all speeds. A disadvantage of this concept is that the operator must hold the control lever to the left or right to increase or decrease the speed the entire time the vehicle speed is changing. To command a large speed change, the operator needs to hold the control lever in the proper position for the long time period required to accomplish the speed change. Some implementations of this control concept provide a means for the vehicle to remember a specific speed and easily return to it. This may be accomplished by a push button which, when depressed, remembers the current speed. This speed can be automatically returned to by moving the control lever to a specific position. The incrementing control must be used to attain speeds other than the remembered speed. This control does not provide a simple method to preset a vehicle speed prior to vehicle movement.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a control device for an infinitely variable transmission that overcomes the difficulties associated with the above control concepts.
The control device of the present invention includes a control lever that is movable along a guide slot and whose position within the slot indicates the commanded vehicle speed and direction. The control lever is moved forward from a zero speed position to a maximum forward speed position. Intermediate the zero speed position and forward speed position is a set point position corresponding to a set point speed. A set speed adjuster, such as a potentiometer, enables the operator to adjust the set point speed that is commanded when the control lever is placed in the set point position. The transmission speed for positions of the control lever between the zero and the set point positions varies proportionally between zero and the set point speed. Likewise, the transmission speed for positions of the control lever between the set point position and the maximum forward speed position varies proportionally between the set point speed and the maximum forward speed. The control lever is movable in a reverse direction for reverse direction and speed selection. In one embodiment of the control device, the maximum reverse speed is variable and equal to the set point speed.
In another embodiment, two set point speeds can be adjusted. A toggle switch allows the operator to switch between the two set point speeds to quickly change the transmission speed between the two set points without moving the control lever. The toggle switch may be hand or foot operated.
In a further embodiment, both a set point speed and a maximum speed can be adjusted. The set point speed corresponds to the set point position of the control lever while the maximum speed corresponds to the maximum speed position of the control lever.
In yet another embodiment of the invention, the control lever is movable between a minimum speed position and the maximum speed position where the minimum speed may be zero or a small value close to, but not equal to, zero. As used in the claims that follow, the term “minimum speed” includes a zero speed.
REFERENCES:
patent: 4594666 (1986-06-01), Cornell
patent: 4864894 (1989-09-01), Falzoni
patent: 5142928 (1992-09-01), Buti et al.
patent: 5527232 (1996-06-01), Seidel et al.
patent: 6080074 (2000-06-01), Ulbrich et al.
patent: 2303183 (1997-02-01), None
patent: 09123780 (1997-05-01), None
Easton David Joseph
Newendorp Bruce Craig
Ruckert Dieter
Tarasinski Nicolai
Deere & Company
Marmor Charles A
Parekh Ankur
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