Land vehicles – Wheeled – Attachment
Reexamination Certificate
1998-12-02
2001-04-03
Swann, J. J. (Department: 3611)
Land vehicles
Wheeled
Attachment
C340S440000, C414S636000
Reexamination Certificate
active
06209913
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to industrial vehicles such as forklifts, and more particularly, to an apparatus for restricting pivoting of a pivotal axle.
Known industrial vehicles, such as forklifts, employ pivotal axles to improve vehicle stability. For example, an axle, to which rear wheels are mounted, is supported pivotally with respect to the body of a forklift. However, if the axle pivots when the forklift turns and tilts the body, this may destabilize the vehicle.
Accordingly, Japanese Unexamined Patent Publication No. 58-211903 proposes a forklift employing an axle pivot control apparatus that restricts pivoting of its axle in accordance with the centrifugal force produced when the forklift turns. The forklift includes a centrifugal force sensor and an apparatus for locking the axle. The sensor detects the centrifugal force applied to the forklift. If the centrifugal force detected by the sensor exceeds a predetermined value, the control apparatus locks the axle to restrict futher pivoting. The axle is thus locked when the forklift turns. This suppresses tilting of the forklift in its lateral direction when the forklift turns and thus maintains vehicle stability.
Japanese Unexamined Patent Publication No. 58-167215 teaches a forklift employing an axle pivot control apparatus that locks the axle in accordance with the weight of the load carried on the forks and the position of the forks.
The axle is locked when the vehicle's center of gravity is raised causing instability of the vehicle. That is, the axle is locked if the forks are lifted to a high position when carrying a heavy load. This keeps the forklift stable when handling loads.
When employing an axle pivot control apparatus such as those described above, the forklift operator should be notified of abnormalites in and actuation of the apparatus. For example, if the operator completely relies on the control apparatus, the operator may continue operation of the forklift even under undesirable circumstances. Alternatively, the operator may become overcautious when unaware of whether the control apparatus has been actuated. In such case, the functions of the axle pivot control apparatus are less effective.
Additionally, in a forklift employing an axle pivot control apparatus that is actuated by more than one factor, the forklift operator should be notified of the factor actuating the control apparatus. For example, if the operator knows whether the axle is locked due to a raised center of gravity or a large centrifugal force, the operator can respond appropriately. This would allow the functions of the control apparatus to be fully effective.
Thus, there are various kinds of information related to the axle pivot control apparatus of which the operator should be notified such as the occurrence of an abnormality, the factor actuating the control apparatus, and the current status of the control apparatus. However, many meters and indicators must be arranged on the instrument panel in addition to the indicators related to the axle pivot control apparatus. This restricts available space and makes it difficult to display all information related to the axle pivot control apparatus. To provide sufficient space, the size of the meters must be minimized. However, this would lower the visibility of the meters and indicators on the instrument panel.
SUMMARY OF THE INVENTION
Accordingly, it is an objective of the present invention to provide an industrial vehicle axle pivot control apparatus that notifies the operator of more than one piece of information related to pivoting of the axle.
To achieve the above objective, the present invention provides an industrial vehicle, including an axle to which wheels are mounted and supported to pivot vertically relative to a body of the vehicle, and a pivot control apparatus for controlling pivoting of the axle. The industrial vehicle further includes a determiner for determining whether an abnormality has occurred in the pivot control apparatus. A warning lamp has two or more different modes. The modes include an abnormality mode for indicating the occurrence of an abnormality in the pivot control apparatus and a normality mode for indicating normal functioning of the pivot control apparatus. A notifier for notifying an operator of two or more different pieces of information using the warning lamp. The warning lamp enters the abnormality mode to indicate the occurrence of an abnormality when the determiner determines that an abnormality has occurred in the pivot control apparatus, and the warning lamp enters the normality mode to indicate normal functioning of the pivot control apparatus when the determiner determines that the pivot control apparatus is functioning normally.
In another aspect of the present invention, a method for controlling axle pivot in an industrial vehicle including an axle to which wheels are mounted and supported to pivot vertically relative to a body of the vehicle is provided. The method includes determining whether an abnormality has occurred in a pivot control apparatus that regulates pivotal motion of the axle and controlling a warning lamp to indicate the occurrence of an abnormality, if an abnormality has occurred, and to indicate normal functioning of the pivot control apparatus when no abnormality has occurred.
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Ishikawa Kazuo
Nogawa Kuniharu
Bottorff Christopher
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Morgan & Finnegan L.L.P.
Swann J. J.
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