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US-12623739-B2 - Automatic axle lift system

US12623739B2US 12623739 B2US12623739 B2US 12623739B2US-12623739-B2

Abstract

An automatic axle lift system including a first sensor circuit configured to detect the presence of a brake signal and a turn signal and, in response, to generate a lift command signal that lifts an axle or a set of axles of a vehicle. The automatic axle lift system also includes a second sensor circuit that detects the lift command signal and, in response, generates a caution light signal. The automatic axle lift system includes a third sensor circuit that detects the lift command signal and, in response, latches the second sensor circuit to maintain the lift command signal.

Inventors

  • Robert A. Erwin
  • Paul Lovejoy

Assignees

  • 4E Ltd.

Dates

Publication Date
20260512
Application Date
20241007

Claims (7)

  1. 1 . An automatic axle lift system comprising: a first sensor circuit configured to detect the presence of a brake signal and a turn signal and, in response, to enable a lift command signal that lifts an axle of a vehicle; a second sensor circuit configured to detect the lift command signal and, in response, to enable a caution light signal; and a third sensor circuit configured to detect the lift command signal and, in response, to latch the first sensor circuit to maintain the lift command signal, wherein the third sensor circuit is further configured to detect the caution light signal and, in response, to disable the latch of the first sensor circuit, thereby disabling the lift command signal.
  2. 2 . The automatic axle lift system as set forth in claim 1 , wherein the second sensor circuit enables the caution light signal after a first delay period.
  3. 3 . The automatic axle lift system as set forth in claim 2 , wherein the third sensor circuit disables the latch of the first sensor circuit after a second delay period after detecting the caution light signal.
  4. 4 . The automatic axle lift system as set forth in claim 3 , wherein the first sensor circuit includes a first relay that is activated by the turn signal.
  5. 5 . The automatic axle lift system as set forth in claim 4 , wherein the first sensor circuit further includes a second relay that is activated by the brake signal.
  6. 6 . The automatic axle lift system as set forth in claim 5 , wherein the second sensor circuit includes a third relay that is activated by an output of the second relay.
  7. 7 . The automatic axle lift system as set forth in claim 6 , wherein the third sensor circuit includes a fourth relay that is activated by an output of the third relay.

Description

TECHNICAL FIELD The present application relates generally to a control system for automatically raising and lowering an auxiliary axle or multiple auxiliary axles of a vehicle. BACKGROUND Heavy load vehicles, such as dump trucks, are often equipped with one or more auxiliar (or lift) axles that may be raised and lowered if load conditions allow it. A lift axle, also called a retractable axle, raises the vehicle tires so that the tires are not touching the road surface. This improves fuel economy by reducing rolling resistance and reduces maintenance and tire wear. However, lifting the axle also increases road wear. A lift axle may be fixed or steerable. A steerable axle has a pivoting mechanism to allow the axle wheels to turn themselves to better follow the curve without sliding sideways, resulting in better handling and control. Failure to lift an axle, particularly a fixed axle, during a tight turn causes the wheels to be dragged sideways on the pavement, damaging both the road and the tires. A lift axle may be lifted by means of a manual switch when the vehicle approaches a turn, such as at an intersection. However, after the turn is completed, the driver may forget to lower the lift axle again. This is particularly true if the driver must wait for a long duration for a traffic light to change. Thus, a manual axle lift system relies on the driver to remember to both raise and lower the lift axle. Thus, there is a need for an automatic system for raising and lowering an auxiliary (or lift) axle of a vehicle. There is a need for an automatic system for raising and lowering an auxiliary (or lift) axle that requires no driver interaction. SUMMARY It is a primary object of the present disclosure to provide an automatic axle lift system comprising: i) a first sensor circuit configured to detect the presence of a brake signal and a turn signal and, in response, to enable a lift command signal that lifts an axle of a vehicle; ii) a second sensor circuit configured to detect the lift command signal and, in response, to enable a caution light signal; and iii) a third sensor circuit configured to detect the lift command signal and, in response, to latch the first sensor circuit to maintain the lift command signal. The third sensor circuit is further configured to detect the caution light signal and, in response, to disable the latch of the first sensor circuit, thereby disabling the lift command signal. In one embodiment, the second sensor circuit enables the caution light signal after a first delay period. In another embodiment, the third sensor circuit disables the latch of the first sensor circuit after a second delay period after detecting the caution light signal. In still another embodiment, the first sensor circuit includes a first relay that is activated by the turn signal. In yet another embodiment, the first sensor circuit further includes a second relay that is activated by the brake signal. In a further another embodiment, the second sensor circuit includes a third relay that is activated by an output of the second relay. In a still further embodiment, the third sensor circuit includes a fourth relay that is activated by an output of the third relay. Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: FIG. 1 is an illustration of a dump truck equipped with an automatic axle lift system according to the principles of the disclosure. FIG. 2 is a schematic of an automatic axle lift system according to the principles of the disclosure. FIG. 3 is a schematic of an axle lift control unit according to the principles of the disclosure. FIG. 4 is a flow diagram illustrating the operation of an automatic axle lift system according to the principles of the disclosure. DETAILED DESCRIPTION FIGS. 1 through 4, discussed below, and the various embodiments used to describe the pr