Motor vehicles – Manually actuated controlling devices – With transmission control
Reexamination Certificate
1999-07-20
2001-05-29
Culbreth, Eric (Department: 3618)
Motor vehicles
Manually actuated controlling devices
With transmission control
C074S473170, C074S481000, C180S315000
Reexamination Certificate
active
06237711
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 allows simple interchangeability between foot and hand controls for controlling the ground speed of lawn tractors, lawn and garden tractors and front-mount mowers having variable speed transmissions, such as hydrostatic or continuously variable transmissions.
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 separate combinations of hand and foot controls to select the direction of travel and to control the vehicle speed.
One conventional system utilized to control the ground speed of the types of off-road vehicles mentioned above, includes a treadle pedal which is essentially a heel and toe forward and reverse control mechanism. With the treadle pedal control system, an operator normally places his foot on the pedal in such a way that the toe of the operator's foot would contact one portion of the treadle pedal and the heel would contact another portion. To drive the vehicle in the forward direction, the operator presses his toe forward thereby raising his heel off of the vehicle footrest. To change the direction of movement to reverse or to slow it down, the operator would increase the pressure on his or her heel until the vehicle eventually came to the neutral position and to a complete stop; and then continue pressing his heel down toward the foot rest in order to produce vehicle movement in the reverse direction.
The conventional treadle pedal system has proved to have three significant problems. The first relates to operator discomfort which results from the fore-and-aft movement of the foot. The second, somewhat related to the first, relates to the difficulty in modulating the vehicle's speed in either the forward or reverse direction because the conventional treadle pedal design requires that the operator keep his foot on both the forward control and reverse control portions of the pedal simultaneously. Third, because the operator's leg is suspended above the foot rest, and his foot is located on a movable pedal, the foot cannot maintain contact with the foot rest that could provide foot stability. Accordingly, vehicle speed control over rough terrain is sometimes difficult to regulate.
Another ground speed control system developed for off-road vehicles is the dual pedal side-by-side system. The details of this system are disclosed in U.S. Pat. No. 4,759,417 dated Jul. 26, 1988 issued to Wanie et al. and commonly assigned to the assignee of the present application, the disclosure of which is hereby incorporated by reference. Both pedals occasionally require that the right foot and leg be lifted and the foot placed on the correct pedal in order to move the vehicle in the desired direction.
A variation of a two pedal system wherein the forward pedal is closer to the front of the vehicle than the reverse pedal is disclosed in U.S. Pat. No. 5,048,638 dated Sep. 17, 1991 issued to Duncan et al. and commonly assigned to the assignee of the present application, the disclosure of which is hereby incorporated by reference.
These 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.
Conventional hand controls for off-road vehicles require that the operator remove at least one hand from a steering wheel to reach a control lever and to move it to the appropriate location. During the movement of the operator's hand from the steering wheel to the control lever, the operator risks interrupting his or her his concentration from the task being performed with the vehicle in order to concentrate on moving his hand control to the proper position, thereby reducing productivity and operating comfort. Thus, there is presently a tendency toward providing such vehicles with foot controls for general use.
Therefore, many manufacturers of off-road vehicles supply base models of such vehicles with foot controls (and often the aforementioned “cruise control” lever). While there is a general trend toward the use of pedal systems, however, certain operators maintain a preference for hand controls. In addition, persons with certain physical characteristics or disabilities are unable to use a pedal system. Therefore, sporadic conversions are made from foot control systems to hand control systems. However, exchanging control linkages and components is often cumbersome, as drilling, welding, and/or custom fabrication may be required.
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 allows for quick, easy and inexpensive conversion between pedal and hand controls.
SUMMARY OF THE INVENTION
According to the present invention, a ground speed and direction control assembly for a vehicle is provided. The assembly includes a system of linkages which are adaptable for use with both hand and foot controls and permits a simple, straightforward conversion between hand and foot control linkages.
The foot controls of the preferred embodiment 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 foot 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 temporarily achieve a speed in excess of the cruise control setting. The cruise control operates only for forward travel, and when the brake pedal is depressed, the hand lever is pulled back to a neutral position.
The ground speed and direction control assembly may be converted to hand controls by removing the foot control linkages and substituting a fixed connection for the lost-motion connection between the hand lever and the transmission.
The preferred embodiment utilizes a hydrostatic transmission and includes a neutral return assembly which ensures that the transmission is placed in neutral as the brake is actuated.
The preferred embodiment also utilizes an intermediate shaft that serves as a centralized connection for use with both the foot pedal and hand control linkages, as well as the neutral return assembly.
REFERENCES:
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: 5263385 (1993-11-01), Hirata et al.
patent: 5509496 (1996-04-01), Erickson et al.
patent: 5586955 (1996-12-01), Wanie
patent: 5842378 (1998-12-01), Zellmer
Culbreth Eric
Deere & Company
LandOfFree
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