Communications: electrical – Land vehicle alarms or indicators – External alarm or indicator of movement
Reexamination Certificate
1999-03-30
2001-05-29
Hofsass, Jeffery (Department: 2736)
Communications: electrical
Land vehicle alarms or indicators
External alarm or indicator of movement
C340S467000, C340S465000, C340S475000
Reexamination Certificate
active
06239696
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a signal light system for self-propelled agricultural equipment, the system conforming to the enhanced lighting standards required for on-road use. The invention provides warning, turn and braking signals for equipment of a type having no brake pedal.
BACKGROUND OF THE INVENTION
The 1996 revisions (ASAE 279.10) to ASAE standard 279.9 for the lighting and marking of agricultural equipment when traveling on a highway require that tractors and self-propelled farm equipment must have two amber warning lights, visible from the front and rear, and flashing in unison at a rate of 60 to 85 flashes per minute. Turn signals are required and the amber warning lights must also serve as the turn indicators. When a turn is signaled, the amber light in the direction of the turn must flash and the amber light in the direction opposite the turn must become steady burning. The amber flashing warning lamp in the direction of turn must increase in flashing rate a minimum of 20 flashes per minute, so as to flash at a rate of at least 80 but no greater than 110 flashes per minute. In addition, a red tail lamp or an additional amber lamp must flash in the direction of turn and in unison with the amber flashing warning lamp.
Typically, the signal for energizing the brake lamps on a vehicle is derived from a switch operated either by a brake pedal which is depressed to cause deceleration, or by the increase in pressure in the hydraulic braking system when the brake pedal is depressed. However, some agricultural equipment, such as the model HW340 windrower currently marketed by New Holland North America, Inc., New Holland Pa., is propelled by hydraulic motors which drive the wheels. The equipment has no hydraulic brake system and does not have a brake pedal.
PRIOR ART
U.S. Pat. No. 4,070,562 discloses a system for warning an operator when there is a sudden acceleration/deceleration in wheel speed such as might occur when the brakes are applied or the wheel speed accelerates too rapidly on an icy road. A sensor senses the speed or rate of wheel rotation over first and second intervals of time and computes the acceleration/deceleration from the sensed speed. When the wheel acceleration/deceleration exceeds a threshold, an audible or visible warning is generated to warn the operator of the vehicle that an abnormal running condition exists.
U.S. Pat. No. 4,357,594 discloses a warning system for a vehicle having a brake pedal. The deceleration is determined from an accelerometer, brake pressure, or the sensing of wheel speed and one or more brake lamps are turned on depending on the vehicle deceleration.
U.S. Pat. No. 5,498,929 teaches that an adapter may be provided to connect the lamp circuits on a towed agricultural implement to the lamp circuits of a towing vehicle so that operation of the lamps on the implement conforms to ASAE standard 279.10.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a warning, turn and signal light system for a vehicle having no brake pedal.
Another object of the invention is to provide a warning, turn and braking signal light system for agricultural equipment having no brake pedal, the system producing visible warning, turning and braking indications according to ASAE standards for on-road use of agricultural equipment.
A further object of the invention is to provide a signal light system for self-propelled agricultural equipment having no brake pedal, the system comprising a left brake lamp and a right brake lamp visible from the rear of the equipment; left and right turn signal switches, each switch having an active state and an inactive state; a ground speed sensor; and a controller for sensing the states of the switches, the controller being responsive to the ground speed sensor for computing the acceleration/deceleration of the equipment; the controller including means for comparing the computed acceleration/deceleration with a deceleration threshold and enabling the left brake lamp and the right brake lamp according to the states of the turn signal switches only if the equipment deceleration exceeds the deceleration threshold.
The controller includes means for enabling the right and left brake lamps as long as the equipment deceleration exceeds the deceleration threshold, and for a short interval of time after the equipment deceleration no longer exceeds the threshold. The controller also includes means for comparing the ground speed of the equipment with a speed threshold and enabling the deceleration comparing means only after the ground speed exceeds the speed threshold. The controller enables the left brake lamp and right brake lamp for an extended interval of time if, during said short interval, the ground speed drops below the speed threshold.
Yet another object of the invention is to provide, in self-propelled agricultural equipment having left and right turn signal switches each having an active and an inactive state and left and right brake lamps but no brake pedal, a method of controlling the brake lamps, the method comprising sensing the ground speed of the equipment; when the ground speed exceeds a threshold speed, initiating computation of the acceleration/deceleration of the equipment from the sensed ground speed; when the deceleration exceeds a deceleration threshold, enabling the left and right brake lamps according to the states of the turn signal switches for as long as the deceleration exceeds the deceleration threshold and for a short interval of time thereafter; and, if the ground speed falls below the threshold speed during the short interval of time, enabling the left and right brake lamps according to the states of the turn signal switches for an extended interval of time.
Other objects and advantages of the invention will become obvious from consideration of the following description and the accompanying drawings.
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Berger John G.
Ehrhart Philip J.
Griffin & Szipl, P.C.
Hofsass Jeffery
New Holland North America Inc.
Tweel , Jr. John
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