Land vehicles – Wheeled – Occupant propelled type
Reexamination Certificate
1999-07-20
2001-08-28
Mai, Lanna (Department: 3619)
Land vehicles
Wheeled
Occupant propelled type
C180S333000, C074S473280, C074S473280, C074S481000
Reexamination Certificate
active
06279937
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved assembly for controlling the ground speed of an off-road vehicle and, more specifically, relates to an improved transmission linkage which provides an intermediate shaft plate which serves as a centralized location for joining a ground speed and direction control assembly capable of both hand and foot control, as well as a neutral return assembly to a transmission.
2. Description of Related Art
It is well known to provide off-road vehicles, specifically lawn tractors, lawn and garden tractors, and front-mount mowers with systems for controlling their ground speed. Typically, variable speed transmissions such as hydrostatic transmissions or continuously variable transmissions utilized in off-road vehicles such as those listed above have used different combinations of hand and foot controls to select the direction of travel and to control the relative vehicle speed.
Conventional systems utilized to control the ground speed of the types of off-road vehicles mentioned above include a hand lever controls, a treadle pedal, or a dual pedal side-by-side system (such as that disclosed in U.S. Pat. No. 4,759,417 dated Jul. 26, 1988 issued to Wanie et al., the disclosure of which is hereby incorporated by reference).
The pedal systems are often coupled with a hand-operated “cruise control” lever which is generally used to maintain a specified forward speed, eliminating the need for constant application of foot pressure to keep the vehicle moving forward at a desired rate of speed.
Off-road vehicles are also commonly provided with a neutral return which will place a transmission in neutral (or disengage the transmission) when a brake is applied.
The various systems involved in controlling a variable speed transmission of such a vehicle require a number of mechanical linkages. Where foot and hand controls are used in conjunction with a neutral return, the linkages and their attachments to each other are often complex, difficult to service and to modify for special needs of operators.
Accordingly, there is a need for an improved assembly for controlling the ground speed and direction of travel of maneuverable off-road vehicles having variable speed transmissions such as variable speed hydrostatic transmissions; which provides a centralized point of attachment to the transmission of hand and foot controls, as well as a neutral return system.
SUMMARY OF THE INVENTION
According to the present invention, an off-road vehicle is provided with a transmission control linkage including an intermediate shaft plate which eliminates the need for multiple and complex connections to coordinate the functions of the ground speed and direction control assembly and a neutral return assembly with a variable speed transmission.
An intermediate shaft plate is utilized as a central point of attachment to a transmission for a control rod employed for hand and/or foot pedal controls, a neutral return. The central point of attachment aids in the conversion of the transmission linkage from foot pedal to hand lever control. The intermediate shaft plate coordinates the functions of the speed and direction control assembly and the neutral return and transmits the output of both assemblies to the transmission by a single control rod attached to the transmission.
In a preferred embodiment of the present invention, a ground speed and direction control assembly for a vehicle is provided which includes a system of linkages which are adaptable for use with both hand and foot controls with a simple, straightforward conversion. The foot controls are provided which include a forward pedal and a reverse pedal, as well as a brake pedal. When the foot controls are in use, the unit may also include a cruise control lever which eliminates the need for an operator to maintain constant pressure on a pedal. The foot controls are coupled to a control shaft which in turn is coupled to a variable speed transmission so that the vehicle speed may be varied by changing foot pressure on the pedals. A hand lever is included in the assembly and may be used as a cruise control to maintain travel speed without having to hold the forward pedal down. When used as a cruise control, the hand lever is operatively coupled to the transmission by a lost motion connection which enables an operator to press further on the forward foot pedal to achieve speed beyond the cruise control setting. The cruise control operates only for forward travel. The ground speed and direction control assembly may be converted to hand controls by substituting a tight-fit connection between the hand lever and the transmission in place of a lost-motion connection used for the cruise control function.
A neutral return assembly is also provided so that, when the brake pedal is depressed, the transmission will return to its neutral position.
In the preferred embodiment, an intermediate shaft plate which operates as a centralized connection between the foot pedals (forward, reverse and brake), hand lever, neutral return assembly and the transmission is provided to which control rods from the foot pedals, a hand lever and the transmission are pinned. The intermediate shaft plate includes an internal cam profile which may be engaged by a bearing attached to a neutral return arm included in the neutral return assembly. Actuation of the brake pedal rotates the neutral return arm, whose bearing forces the intermediate shaft plate into a neutral position as the bearing follows the internal cam profile. The neutral position of the intermediate shaft plate corresponds to a neutral position of the transmission due to interconnection of the transmission and the intermediate shaft plate by the transmission control rod.
REFERENCES:
patent: 4221277 (1980-09-01), Mastropieri
patent: 4346617 (1982-08-01), Schroeder et al.
patent: 4620575 (1986-11-01), Cuba et al.
patent: 4759417 (1988-07-01), Wanie et al.
patent: 4883137 (1989-11-01), Wanie et al.
patent: 5022477 (1991-06-01), Wanie
patent: 5048638 (1991-09-01), Duncan et al.
patent: 5228360 (1993-07-01), Johnson
patent: 5509496 (1996-04-01), Erickson et al.
patent: 5586955 (1996-12-01), Wanie
patent: 5842378 (1998-12-01), Zellmer
Deere & Company
Mai Lanna
To Toan
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