WO1999021065A1

WO1999021065A1 - Control system for powered cargo bed

Info

Publication number: WO1999021065A1
Application number: PCT/US1998/022418
Authority: WO
Inventors: Paul Y. Boucher
Original assignee: Tooling Technology Centre (U.S.), Inc.
Priority date: 1997-10-23
Filing date: 1998-10-23
Publication date: 1999-04-29
Also published as: CA2306734A1; AU1115899A

Abstract

A control system (10) for a lifting and lowering apparatus for a vehicle, controls the operation of an elevator drive arrangement in response to actuation of controls by an operator and after interrogation of a number of vehicle conditions. Among the conditions are the location of the lifting and lowering apparatus as determined by upper (21) and lower (22) limit sensors, and actuators that can be manipulated by the operator. In the event of malfunction or an incorrect vehicle condition, operation of the elevator drive is precluded. A malfunction can result in the issuance of a disabling signal that shuts off the engine. Other conditions that are monitored include the parking brake setting (27), the transmission being in neutral (26), the motion of the vehicle (25), and the availability of accessory power (23). Outputs (73, 74, 75) are provided for issuing audible and/or visual warnings. The logic is implemented in integrated circuitry (40).

Description

Control System for Powered Cargo Bed

Background of the Invention

FIELD OF THE INVENTION

This invention relates generally to systems for controlling the operation of lift arrange-

ments for vehicles, and more particularly, to a control system that interrogates sensors of a variety of vehicle and lift arrangement conditions before permitting energization of the lift arrangement drive

DESCRIPTION OF THE RELATED ART

A well-known disadvantage in the use of pick up trucks and the like is that of loading and unloading, particularly heavy or awkward cargo when a loading dock of

appropriate height is not available A number of approaches have been attempted in the

prior art to ameliorate this problem, including the selectable lowering of the cargo bed of the vehicle, or a portion thereof It is readily understood, however, that if mobile lifts

are to be operated safely, certain vehicle conditions must be examined before a cargo area

of a vehicle can safely be lowered or raised For example, the vehicle preferable should

not be traveling during lift actuation In addition, the lift itself should be examined to

determine whether it is overloaded

There is a need, therefore, for a control arrangement that will preclude the operation of a cargo lift unless certain predetermined vehicle and/or lift conditions are

within predetermined parameters

It is, therefore, an object of this invention to provide a control system for a

powered cargo lifting and lowering portion of a vehicle It is another object of this invention to provide an arrangement that monitors

certain vehicle conditions before allowing a cargo lift to be operated.

It is also an object of this invention to provide an arrangement that monitors certain conditions of the lift arrangement before allowing same to be operated.

It is a further object of this invention to provide a system that will control the operation of a vehicle engine in response to indication of intended actuation of the

powered cargo lifting and lowering portion of the vehicle.

It is additionally an object of this invention to provide a system that will monitor

the powered cargo lifting and lowering portion of the vehicle to determine the presence of fault.

Summary of the Invention

The foregoing and other objects are achieved by this invention which provides,

in a first system aspect thereof, a control system for a lifting and lowering apparatus for

a vehicle having a vehicle drive arrangement. In accordance with the invention, there is

provided an elevator drive arrangement for effecting vertical displacement of a lifting and lowering apparatus relative to the vehicle. The elevator drive arrangement has a first

input for receiving electrical energy for powering the elevator drive arrangement,

whereby the lifting and lowering apparatus is displaced between uppermost and

lowermost positions. An upper limit detector has an upper limit output for producing an

upper limit electrical characteristic having a first characteristic state responsive to the lifting and lowering apparatus being in a predetermined upper position relative to the

vehicle, and a second characteristic responsive to the lifting and lowering apparatus being in another position. Similarly, a lower limit detector has a lower limit output for

producing a lower limit electrical characteristic having a first characteristic state responsive to the lifting and lowering apparatus being in a predetermined lower position relative to the vehicle, and a second characteristic that is responsive to the lifting and

lowering apparatus being in another position. There is additionally provided an operator interface having an up actuator that is manipulable by the operator for producing an

output of the operator interface and up indication. There is also provided a down actuator that is manipulable by the operator for producing at an output of the operator interface a down indication. In accordance with this aspect of the invention, there is

provided a vehicle drive displacement system for disabling the vehicle drive arrangement in response to a disable-vehicle-drive indication. A controller has an upper limit input for receiving an upper limit signal responsive to the upper limit electrical characteristic, a

lower limit input for receiving a lower limit signal responsive to the lower limit electrical

characteristic, an operator input coupled to the operator interface, and a disable-vehicle-

drive output for providing the disable-vehicle-drive indication.

In one embodiment of the invention, wherein the vehicle is of the type having a

vehicle drive engine having an ignition system having enabled and disabled conditions,

the vehicle drive disabling system includes an ignition system disabling system for urging

the ignition system into the disabled condition, whereby the vehicle drive engine is

disabled. The ignition system is of the type that has active and inactive states, the active state being available only during the enabled condition, such as when power is available.

However, the inactive state is available during enabled and disabled conditions. That is, in the context of a conventional vehicle, power may be applied to the ignition system, but the engine may not be operating.

In another embodiment of the invention, the controller is additionally provided with an indicator output for producing an indicator signal responsive to a fault

determination by the controller arrangement. The indicator output may be, in certain embodiments, coupled to an audible warning device, or a visual warning device, such as an indicator on the instrument panel of the vehicle or on a portion of the vehicle visible from the exterior thereof. For example, the operator interface portion of the system may

be installed in a housing tethered by a cable to the vehicle, and may have thereon visual or audible indicators.

In still a further embodiment of the invention, the controller is provided with a parking brake input for receiving a parking brake signal responsive to a parking brake

condition of the vehicle. Thus, the controller would be enabled to determine whether the

parking brake of the vehicle should be applied in order to permit operation of the lifting

and lowering arrangement. Similarly, the controller is provided in certain embodiments

with a neutral safety input for receiving a neutral safety signal responsive to a neutral

transmission condition of a drive transmission of the vehicle. Such an input would permit

the controller to determine whether the lift arrangement should be operated during

periods that the transmission of the vehicle is in neutral, or otherwise disengaged.

In an advantageous embodiment of the invention, the controller is provided in the

form of an integrated logic circuit having a plurality of logic circuit input for receiving

a respective plurality of input logic signals, in a plurality of logic circuit outputs for providing a respective plurality of output logic signals, the output logic signals being

responsive to the input logic systems In one embodiment of this integrated circuit aspect

of the invention, the plurality of logic circuit inputs may include an upper limit input for

receiving an upper limit signal responsive to the upper limit electrical characteristic, a lower limit input for receiving a lower limit signal responsive to the lower limit electrical characteristic; an ignition enablement input for receiving a signal responsive to the

enabled and disabled states of the ignition system, an up actuation input responsive to the up indication of the up actuator of the operator interface, and a down actuation input

responsive to the down indication of the down actuator of the operator interface In a further embodiment, as previously discussed, the logic circuit may have inputs for a

parking brake input that receives a parking brake signal responsive to a parking brake condition of the vehicle, and a neutral safety input for receiving a neutral safety signal responsive to a neutral transmission condition of the drive transmission of the vehicle.

In addition, a logic circuit input is provided in certain embodiments of the invention for

receiving an accessory power signal responsive to the availability of accessory power.

As indicated, the integrated logic circuit is provided with a plurality of logic circuit outputs that include, for example, an up enablement output for providing an up drive signal to the elevator drive arrangement for effecting upward displacement of the

lifting and lowering apparatus relative to the vehicle Also, there is provided a down

enablement output for providing a down drive signal to the elevator driver arrangement

for effecting downward displacement of the lifting and lowering apparatus relative to the

vehicle In other embodiments, the logic circuit outputs include a drive disablement output for providing a signal to a vehicle drive disabling system for urging the vehicle drive into a disabled condition. In still further embodiments, the logic circuit outputs

include an indicator output for producing a signal for indicating the predetermined controller system condition, and a lock output for activating a lock arrangement of the vehicle.

Further in regard of the integrated logic circuit aspect of the invention, each logic circuit input has associated therewith a logic circuit input interface circuit for receiving

a respective one of the input logic signals. Such an input interface circuit may include an amplifier. In addition, each of the logic circuit outputs is provided with an associated logic circuit output interface circuit via which is provided a respective one of the output

logic signals. The logic circuit output interface circuits, in one embodiment of the invention, each include a semi-conductor switch that drives the coil of an associated isolating relay. In this matter, the integrated logic circuit is electrically isolated from the

elevator drive arrangement, as well as other vehicle systems, such as the lock arrange-

ment, the engine disabling system, and the warning indicators.

In accordance with a further aspect of the invention, a control arrangement for a lifting and lowering apparatus for a vehicle having a vehicle driver arrangement is provided with an integrated circuit having a plurality of circuit inputs for receiving a

respective plurality of input signals. The integrated circuit has a plurality of circuit

outputs for providing a respective plurality of output signals. As discussed, there is

provided a plurality of input interface circuits, each associated with a respective one of

the circuit inputs for receiving a respective one of the input signals. Additionally, there is provided a plurality of output interface circuits, each associated with a respective one of the circuit outputs for providing a respective one of the output signals. An operator interface is provided with an up actuator that is manipulable by the operator for producing at an up output of the operator interface an up indication signal. The up

output is coupled to one of the input interface circuits. Also, the operator interface is

provided with a down actuator that is manipulable by the operator for producing at a down output of the operator interface a down indication, the down output being coupled to another of the input interface circuits. A logic system is arranged in the integrated circuit for producing at a predetermined one of the plurality of output interface circuits an up signal for causing the lifting and lowering apparatus to be urged upward, and for producing at a further predetermined one of the plurality of output interface circuits a

down signal for causing the lifting and lowering apparatus to be urged downward.

In accordance with one embodiment of this further aspect of the invention, the

control arrangement is provided with a housing for holding the up actuator and the down

actuator of the operator interface. A communication arrangement is provided for

propagating an operator signal to the integrated circuit from the housing. Such a

communication arrangement could be of any known type, such as a cable tether, or a

radio or infra red communication system.

In addition to the foregoing, there is provided a name assignment system for

assigning a variable name to each of the circuit inputs and the circuit outputs. In one

embodiment, the name assignment system is incorporated within the integrated circuit. As previously discussed in connection with the first aspect of the invention, the

plurality of circuit inputs include an upper limit input for receiving an upper limit signal responsive to the upper limit electrical characteristic; a lower limit input for receiving a lower limit signal responsive to the lower limit electrical characteristic; an ignition enablement input for receiving a signal responsive to the enabled and disabled states of the ignition system; an up actuation input responsive to the up actuation of the up

actuator of the operator interface; and a down actuation input responsive to the down actuation of the down actuator of the operator interface. Additionally, the plurality of

circuit inputs includes a parking brake input for receiving a parking brake signal responsive to a parking brake condition of the vehicle, and a neutral safety input for receiving a neutral safety signal responsive to a neutral transmission condition of a drive transmission of the vehicle. Also, in a further embodiment there is provided an accessory

power input for receiving an accessory power signal responsive to the availability of

accessory power.

With respect to the plurality of circuit outputs, there is provided an up enablement output for providing an up drive signal to the lifting and lowering apparatus for effecting

upward displacement of the lifting and lowering apparatus relative to the vehicle.

Additionally, there is provided a down enablement output for providing a down drive

signal to the lifting and lowering arrangement for effecting downward displacement of the lifting and lowering arrangement relative to the vehicle. In a further embodiment, the circuit outputs include a drive disablement output for providing a signal to the vehicle

drive disabling arrangement for urging the vehicle drive into a disabled condition. Also, the circuit outputs include, in certain embodiments, an indicator output for producing a signal for indicating a predetermined control arrangement condition, and a lock output for activating the lock arrangement of the vehicle

In this further aspect of the invention, there are further provided, as previously noted, a plurality of input interface circuits, each associated with a respective one of the circuit inputs for receiving a respective one of the input signals, in a plurality of output

interface circuits, each associated with a respective one of the circuit outputs for providing a respective one of the output signals Additionally, there is provided a plurality of relays, each associated with a respective one of the plurality of output interface circuits for isolating electrically the integrated circuit

In accordance with a method aspect of the invention, a method of operating a

lifting and lowering apparatus for a vehicle having a vehicle drive arrangement, includes

the steps of

(a) interrogating an operator interface device for determining whether the lifting

and lowering apparatus is desired to be lifted or lowered,

(b) interrogating a lifting and lowering apparatus locator arrangement to

determine the location of the lifting and lowering apparatus relative to the vehicle,

(c) interrogating a vehicle drive sensing arrangement to determine whether the

vehicle is in motion; and (d) determining whether to produce a motion signal for lifting or lowering the

lifting and lowering apparatus in response to the interrogations of steps (a), (b), and (c) In one embodiment of this method aspect of the invention, prior to performing step (d) there are provided the further steps of:

interrogating a parking brake sensor for determining a parking brake condition of the vehicle; and interrogating a neutral safety sensor for determining a transmission gearing

condition of a drive transmission of the vehicle.

In another embodiment, there is provided the further step of interrogating an

accessory power sensor for determining the availability of accessory power. Prior to performing step (d) there is provided the further step of interrogating a vehicle motion

sensor for determining whether the vehicle is in motion. Also, there is provided the step of issuing a vehicle disablement signal for disabling the vehicle drive arrangement.

In still further embodiments of this method aspect of the invention, the performance of step (d) includes the further step of determining whether to produce an

up drive signal to the lifting and lowering apparatus for effecting upward displacement

of the lifting and lowering apparatus relative to the vehicle or a down drive signal to the

lifting and lowering apparatus for effecting downward displacement thereof relative to

the vehicle. Additionally, there is provided the step of issuing a motion signal for

selectably lifting or lowering the lifting and lowering apparatus.

Brief Description of the Drawing

Comprehension of the invention is facilitated by reading the following detailed

description, in conjunction with the annexed drawing, in which: Fig. 1 is a block and line representation of a specific illustrative embodiment of a lift controller aspect of the invention;

Fig. 2 is a block and line representation of an input portion of the embodiment of Fig. 1;

Fig. 3 is a block and line representation of an output portion of the embodiment of Fig. 1;

Fig. 4 is a flow diagram illustrating certain steps of a method aspect of the

invention for disabling the vehicle drive engine when certain vehicle and cargo lift conditions are present; and

Fig. 5 is a flow diagram illustrating certain steps of a method aspect of the invention for raising or lowering the cargo lift arrangement when certain vehicle, cargo lift, and operator conditions are present.

Detailed Description

Fig. 1 is a block and line representation of a specific embodiment of a lift

controller V0 having a plurality of inputs 20 coupled to an input interface 30. The input

interface is coupled to an integrated circuit processor 40 that is coupled at its output to

an output interface 50. Output interface 50 has associated therewith a plurality of

outputs 60 that will be described below. Integrated circuit processor 40 has incorporated

therein a logic system 41 that implements a programmed correlation between information

received via input interface 30 to logically correlated output conditions at outputs 60, via

output interface 50. In addition, integrated circuit processor 40 has a name assignment memory 42 that, in this specific illustrative embodiment of the invention, may be in the form of a table for assigning logical names to the various inputs and outputs, as will be described herein. Also as shown, integrated circuit processor 40 has an oscillator 43 coupled thereto for providing conventional timing signals for operating the integrated circuit processor and facilitating timing functions, also as will be described below.

In the specific embodiment shown in Fig. 1, the various inputs 20 include a bed

raised input 21, a bed lowered input 22, an accessory power input 23, a spare input 24, an engine input 25, and a neutral input 26. Each of these inputs is arranged to receive a signal that corresponds to a specific vehicle (not shown) or lift system (not shown)

condition . Bed raised input 21 receives a signal responsive to whether the vehicle lift system is located at an upward limit thereof. Bed lowered input 22 receives a signal responsive to whether the lift system is located at its lowermost position. Accessory power input 23 receives a signal corresponding to the availability of accessory vehicle

power.

Spare input 24 is provided as additional and unused input capacity to the system.

Engine input 25 receives a signal responsive to whether the engine (not shown) of the

vehicle (not shown) is running. Neutral input 26 receives a signal responsive to whether

the vehicle transmission (not shown) is in gear or in a neutral state. All of these inputs,

and others that are not shown in the specific illustrative embodiment of the invention

represented in this figure, are coupled to input interface 30, which has an electrical structure that will be described in connection with Fig. 2.

Referring to Fig. 2, elements of structure that correspond to those that previously

have been discussed are similarly designated. The various inputs 20 discussed hereinabove with respect to Fig 1 , as well as other inputs, such as parking brake input 27 which receives a signal responsive to whether the parking brake as applied are received at respective inputs of switching amplifiers 31 Each of the switching amplifiers

is coupled at its output to integrated circuit processor 40 The various switching amplifiers all are arranged to receive operating energy from a supply, illustratively 12

volts in this specific embodiment, and each is additionally provided with a second input that is coupled to the supply voltage via a resistor 33 Each of the outputs of switching amplifiers 31 is coupled to a five volt supply via a respectively associated one of resistors 35 With this circuitry, each of switching amplifiers 31 produces an output logical signal that presents to integrated circuit processor 40 a signal responsive to the condition of the

respectively associated input

Referring once again to Fig 1, integrated circuit processor 40, as previously

discussed, is coupled at respective outputs thereof to output interface 50 As shown, the

upward interface is provided with a plurality of output interface circuits 51 that are

coupled to respective relays 52, as shown in Fig 3

Fig. 3 shows each output of integrated circuit 40 to be coupled to a respective

output interface circuit 54 which is connected to an associated relay 5_5 Electrical energy

for each output interface circuit and its associated relay is provided at an input terminal 56 via a current limiting device, such as breaker 57 Each of output interface circuits 54

is provided with an associated voltage divider formed of resistors 62 and 63 that are

joined to one another and to an input of a semiconductor switching element 64

Semiconductor switching element 64 is coupled via a diode 65 to a winding 67 of relay 55 Actuation of the relay winding by the associated output interface circuit 54 results

in a corresponding actuation of contacts 69 that, in this specific embodiment, will cause battery voltage to be, or not to be, as the case may be, applied to the respectively associated one of outputs 60 Referring to Fig 1 once again, outputs 60 include a raise solenoid output 71 that

causes the vehicle lift system (not shown) to be raised, a lower solenoid output 72, which

causes the vehicle lift system to be lowered, a visual warning output 73, which produces a visual indication for the operator (not shown), an outside audible output 74, which causes an audible alarm to be energized that is audible outside of the vehicle, an inside audible output 75, which causes an alarm inside the vehicle to be sounded, a lock output

76, which causes vehicle locks and/or lift bed locks to be enabled, and a kill engine output 77 that causes the vehicle engine to be disabled

Fig 4 is a flow diagram illustrating certain steps of a method aspect of the

invention, particularly directed to disablement of the vehicle drive engine (not shown)

when certain vehicle and cargo lift conditions are present As shown, the routine is started at function block 80 and proceeds to decision block 81 where it is determined

whether the lift is in the raised position This is achieved, in a specific illustrative

embodiment of the invention, by examining the state of an upper limit switch (not shown)

in the cargo lift system (not shown) Such a switch would assume a first state when the

vehicle lift is in the uppermost position, and a second state when the lift is elsewhere along the path of its travel If the lift is in the raised position, the routine is returned to

the top of decision block 81 whereby the interrogation of the upper limit switch continues until it is determined that the lift no longer is in the uppermost position. At that point,

the routine proceeds to decision block 82.

In decision block 82, it is determined whether the vehicle is in a lowered position. This inquiry can include interrogation of a lower limit switch (not shown), or an indication of intermediate position of the lift, such as between the uppermost and lowermost positions. If it is determined that the lift is in a lowermost position, or a sufficiently lowered position, the routine proceeds to decision block 83 wherein the status

of the vehicle parking brake (not shown) is explored. If the parking brake is on, the routine proceeds to decision block 84 wherein the status of the vehicle transmission is examined. If the vehicle is in gear, then a status bid is set to disable the engine, at function block 85. Thus, this routine examines whether the vehicle lift has been lowered, and whether the parking brake is on and the transmission in gear, in order to disable the

engine.

Fig. 5 is a flow diagram that illustrates certain steps of a method aspect of the

invention for raising or lowering the cargo lift arrangement. The figure illustrates the operation of an arrangement wherein certain vehicle, cargo lift, and operator conditions

are present. The routine described in this figure is started at function block 90 which

proceeds to query whether the ignition is on at decision block 91. If the ignition is not

on, the process will proceed to function block 92 where the execution of logic to

determine whether the vehicle is moving is skipped. If the ignition is on, however, the

process proceeds to decision block 94 wherein the status of the parking brake is queried.

If the parking brake is not on, which at this point in the process would also indicate that the ignition is on, the process proceeds to function block 95 where logic is executed to disable the vehicle engine. However, if the parking brake is on, the process proceeds to

decision block 96 where the status of the transmission is queried. If the transmission is in gear, signifying that the ignition is on, the parking brake is on, and the transmission is in gear, the process proceeds back to function block 95 where the engine is disabled.

However, if the transmission is not in gear, then the system queries whether the up button

is pushed at decision block 100 or whether the down button is pushed at decision block 102.

If the up button has been pushed, the cargo bed of the vehicle is raised at function block 101. Alternatively, if the down button is pushed, the cargo bed is lowered a function block 103. In a preferred embodiment of the invention, if both buttons have

been pushed, then the system enters a lock state at function block 105. If it is determined

that neither the up button nor the down button have been pushed, then the process ends

at function block 106.

The process of the present invention can include a number of additional

subroutines embodied in various sections of the logic code that would be implemented

in the embodiment of FIGS. 1, 2, and 3.

One section of logic code is used in a practicable embodiment of the invention to

assign variable names to various registers in integrated circuit 40 of Fig. 1. The names

are stored in name assignment memory 42, and include, for example, the following input

names:

UPLIMIT Cargo bed in raised condition ACC_ON Accessory power on

KILLJDN Engine disabled

UPSWITCH Upper limit switch

DOWNSWITCH Down limit switch

PB_ON Parking brake on

NEU_SFTY Neutral safety switch

FUSE SENSE Blown fuse indication

LED Light-emitting diode status indicator

V1S_WARN Visual warning indicator

The following are names assigned to output registers in this specific illustrative embodiment of the invention

EXT_AUDIBLE Actuate external audible warning device

1NT_AUD1BLE Actuate internal audible warning device

UP_SOL Actuate solenoid for raising the cargo bed

DOWN_SOL Actuate solenoid for lowering the cargo bed

EG_KILL Disable engine signal

LOCK Actuate lock state of lock system for the cargo bed

UNLOCK Actuate unlock state of lock system for the cargo bed

A further section of the logic code determines whether conditions are appropriate

for the vehicle lift to be raised automatically while the vehicle is in motion, in the event the lift system were to lower accidentally without using the operator actuation buttons

This process includes the steps of Determining whether the vehicle ignition key is in the "run" position;

If the key is in the "off position, then execute a routine wherein memory associated with the cargo lift is reset;

Determining whether the parking brake is engaged (If the vehicle ignition key is in the "on" position;

If the parking brake is engaged, execute the routine wherein memory associated with the cargo lift is reset ;

Determining whether the vehicle transmission is in gear;

Executing the automatic cargo lift raising routine (If the vehicle is not in gear);

Determining whether the cargo bed has been raised to the full up position within a predetermined period of time;

If the cargo lift is not raised within the predetermined period of time, execute a routine for raising the cargo bed while the vehicle is in motion; if the cargo lift is not raised after a second predetermined period of time, execute a routine for discontinuing lift drive energy of hydraulic drive to the cargo lift.

Other sections of the logic code serve to measure the timing, or duration, of

certain functions of the cargo bed, and if the predetermined time is exceeded, fault

indications are established that would not clear until the cargo bed has been raised

manually. The fault indication is used, in certain embodiments of the invention, to sound

an internal audible arm, and to disable the vehicle engine once the vehicle has come to

a stop.

In a still further section of logic code, the system determines the presence of an

internal fuse fault. This section will check whether the ignition is on, and whether the

circuit has voltage. If voltage is not present, then a fault indication is issued whereby the LED indicator is caused to blink. In a preferred embodiment, the LED indicator is installed on a control box that may be tethered by a cable, or otherwise communicates

information, to the vehicle. Upon determining that voltage has been restored, the fuse fault indictor is cleared, and the LED indicator on the control box is extinguished. Although the invention has been described in terms of specific embodiments and applications, persons skilled in the art can, in light of this teaching, generate additional

embodiments without exceeding the scope or departing from the spirit of the claimed invention. Accordingly, it is to be understood that the drawing and description in this

disclosure are proffered to facilitate comprehension of the invention, and should not be construed to limit the scope thereof.

Claims

What is claimed is:

1. A control system for a lifting and lowering apparatus for a vehicle having

a vehicle drive arrangement, the control system comprising:

an elevator drive arrangement for effecting vertical displacement of the lifting and lowering apparatus relative to the vehicle, said elevator drive arrangement having a first input for receiving electrical energy for powering said elevator drive arrangement,

whereby the lifting and lowering apparatus is displaced between uppermost and

lowermost positions; upper limit detector means having an upper limit output for producing an upper limit electrical characteristic having a first characteristic state responsive to the lifting and lowering apparatus being in a predetermined upper position relative to the vehicle, and a second characteristic state responsive to the lifting and lowering apparatus being

in another position;

lower limit detector means having a lower limit output for producing a lower limit

electrical characteristic having a first characteristic state responsive to the lifting and

lowering apparatus being in a predetermined lower position relative to the vehicle, and

a second characteristic state responsive to the lifting and lowering apparatus being in

another position; operator interface means having an up actuator manipulable by an operator for

producing at an output of said operator interface means an up indication, and a down

actuator manipulable by the operator for producing at an output of said operator

interface means a down indication; vehicle drive disabling means for disabling the vehicle drive arrangement in

response to a disable-vehicle-drive indication; and controller means having an upper limit input for receiving an upper limit signal responsive to the upper limit electrical characteristic, a lower limit input for receiving a lower limit signal responsive to the lower limit electrical characteristic, an operator input coupled to said operator interface means, and a disable-vehicle-drive output for providing

the disable-vehicle-drive indication. 2. The control system of claim 1, wherein the vehicle is of the type having a vehicle drive engine having an ignition system having enabled and disabled conditions, and said vehicle drive disabling means comprises ignition system disabling means for

urging said ignition system into the disabled condition, whereby said vehicle drive engine

is disabled.

3. The control system of claim 2, wherein said ignition system has active and

inactive states, the active state being available only during the enabled condition, and the

inactive state being available during the enabled and the disabled conditions.

4. The control system of claim 1, wherein said controller means is further

provided with an indicator output for providing an indicator signal responsive to a fault

determination by said controller means.

5. The control system of claim 2, wherein said controller means is further

provided with: a parking brake input for receiving a parking brake signal responsive to a parking

brake condition of the vehicle; and a neutral safety input for receiving a neutral safety signal responsive to a neutral transmission condition of a drive transmission of the vehicle.

6. The control system of claim 1, wherein said controller means comprises an integrated logic circuit having a plurality of logic circuit inputs for receiving a

respective plurality of input logic signals, and a plurality of logic circuit outputs for

providing a respective plurality of output logic signals, said output logic signals being responsive to said input logic signals. 7. The control system of claim 6, wherein said plurality of logic circuit inputs comprises:

an upper limit input for receiving an upper limit signal responsive to the upper

limit electrical characteristic; a lower limit input for receiving a lower limit signal responsive to the lower limit

electrical characteristic; an ignition enablement input for receiving a signal responsive to the enabled and

disabled states of said ignition system; an up actuation input responsive to the up indication of said up actuator of said

operator interface means; and a down actuation input responsive to the down indication of said down actuator

of said operator interface means. 8. The control system of claim 7, wherein said plurality of logic circuit inputs

further comprises: a parking brake input for receiving a parking brake signal responsive to a parking brake condition of the vehicle, and

a neutral safety input for receiving a neutral safety signal responsive to a neutral

transmission condition of a drive transmission of the vehicle

9 The control system of claim 7, wherein said plurality of logic circuit inputs further comprises an accessory power input for receiving an accessory power signal responsive to the availability of accessory power

10 The control system of claim 6, wherein said plurality of logic circuit

outputs comprises an up enablement output for providing an up drive signal to said elevator drive arrangement for effecting upward displacement of the lifting and lowering apparatus relative to the vehicle, and

a down enablement output for providing a down drive signal to said elevator

drive arrangement for effecting downward displacement of the lifting and lowering

apparatus relative to the vehicle 11 The control system of claim 10, wherein said plurality of logic circuit

outputs further comprises a drive disablement output for providing a signal to a vehicle

drive disabling means for urging the vehicle drive into a disabled condition

12 The control system of claim 10, wherein said plurality of logic circuit

outputs further comprises

an indicator output for producing a signal for indicating a predetermined

controller system condition, and a lock output for activating a lock arrangement of the vehicle. 13. The control system of claim 6, wherein there are further provided:

a plurality of logic circuit input interface circuits each associated with a respective one of the logic circuit inputs for receiving a respective one of the input logic signals; and a plurality of logic circuit output interface circuits each associated with a respective one of the logic circuit outputs for providing a respective one of the output

logic signals.

14. The control system of claim 13, wherein there is further provided a

plurality of relay means, each associated with a respective one of said plurality of logic circuit output interface circuits for isolating electrically said integrated logic circuit from said elevator drive arrangement.

15. A control arrangement for a lifting and lowering apparatus for a vehicle

having a vehicle drive arrangement, the control system comprising:

integrated circuit means having a plurality of circuit inputs for receiving a

respective plurality of input signals, and a plurality of circuit outputs for providing a

respective plurality of output signals; a plurality of input interface circuits each associated with a respective one of the

circuit inputs for receiving a respective one of the input signals; and

a plurality of output interface circuits each associated with a respective one of the

circuit outputs for providing a respective one of the output signals. operator interface means having, an up actuator manipulable by an operator for producing at an up output

of said operator interface means an up indication signal, the up output being coupled to one of said input interface circuits, and a down actuator manipulable by the operator for producing at a down

output of said operator interface means a down indication, the down output being coupled to one of said input interface circuits;

and logic means in said integrated circuit means for producing at a predetermined one of said plurality of output interface circuits an up signal for causing the lifting and lowering apparatus to be urged upward, and for producing at a further predetermined one of said plurality of output interface circuits a down signal for causing the lifting and

lowering apparatus to be urged downward.

16. The control arrangement of claim 15, wherein there is further provided:

a housing for holding the up actuator and the down actuator of said operator

interface means; and communication means for propagating an operator signal to said integrated circuit

means. 17. The control arrangement of claim 15, wherein there is further provided

name assignment means for assigning a variable name to each of the circuit inputs and

the circuit outputs.

18. The control arrangement of claim 17, wherein said name assignment

means is incorporated within said integrated circuit means.

19. The control arrangement of claim 15, wherein said plurality of circuit inputs comprises: an upper limit input for receiving an upper limit signal responsive to the upper

limit electrical characteristic;

a lower limit input for receiving a lower limit signal responsive to the lower limit electrical characteristic; an ignition enablement input for receiving a signal responsive to the enabled and disabled states of said ignition system; an up actuation input responsive to the up indication of said up actuator of said

of said operator interface means.

20. The control arrangement of claim 19, wherein said plurality of circuit

inputs further comprises:

a parking brake input for receiving a parking brake signal responsive to a parking

brake condition of the vehicle; and

transmission condition of a drive transmission of the vehicle.

21. The control arrangement of claim 19, wherein said plurality of circuit inputs further comprises an accessory power input for receiving an accessory power

signal responsive to the availability of accessory power.

22. The control arrangement of claim 15, wherein said plurality of circuit outputs comprises:

an up enablement output for providing an up drive signal to the lifting and lowering apparatus for effecting upward displacement of the lifting and lowering

apparatus relative to the vehicle; and a down enablement output for providing a down drive signal to the lifting and lowering apparatus for effecting downward displacement of the lifting and lowering apparatus relative to the vehicle.

23. The control arrangement of claim 22, wherein said plurality of circuit

outputs further comprises a drive disablement output for providing a signal to a vehicle drive disabling means for urging the vehicle drive into a disabled condition. 24. The control arrangement of claim 22, wherein said plurality of circuit

outputs further comprises: an indicator output for producing a signal for indicating a predetermined control

arrangement condition; and

a lock output for activating a lock arrangement of the vehicle.

25. The control arrangement of claim 15, wherein there are further provided:

a plurality of input interface circuits each associated with a respective one of the

circuit inputs for receiving a respective one of the input signals; and

circuit outputs for providing a respective one of the output signals.

26. The control arrangement of claim 25, wherein there is further provided a plurality of relay means, each associated with a respective one of said plurality of

output interface circuits for isolating electrically said integrated circuit means.

27. A method of operating a lifting and lowering apparatus for a vehicle

having a vehicle drive arrangement, the method comprising the steps of: (a) interrogating an operator interface device for determining whether the lifting

and lowering apparatus is desired to be lifted or lowered; (b) interrogating a lifting and lowering apparatus locator arrangement to determine the location of the lifting and lowering apparatus relative to the vehicle; (c) interrogating a vehicle drive sensing arrangement to determine whether the

vehicle is in motion; and (d) determining whether to produce a motion signal for lifting or lowering the lifting and lowering apparatus in response to the interrogations of steps (a), (b), and (c).

28. The method of operating a lifting and lowering apparatus of claim 27,

wherein prior to performing step (d) there are provided the further steps of:

interrogating a parking brake sensor for determining a parking brake condition

of the vehicle; and

interrogating a neutral safety sensor for determining a transmission gearing

condition of a drive transmission of the vehicle. 29. The method of operating a lifting and lowering apparatus of claim 27,

wherein prior to performing step (d) there is provided the further step of interrogating an accessory power sensor for determining the availability of accessory power.

30. The method of operating a lifting and lowering apparatus of claim 27, wherein prior to performing step (d) there is provided the further step of interrogating

a vehicle motion sensor for determining whether the vehicle is in motion. 31. The method of operating a lifting and lowering apparatus of claim 27,

wherein prior to performing step (d) there is provided the step of issuing a vehicle

disablement signal for disabling the vehicle drive arrangement.

32. The method of operating a lifting and lowering apparatus of claim 27, wherein the performance of step (d) comprises the further step of determining whether to produce an up drive signal to the lifting and lowering apparatus for effecting upward displacement of the lifting and lowering apparatus relative to the vehicle or a down drive signal to the lifting and lowering apparatus for effecting downward displacement thereof

relative to the vehicle.

33. The method of operating a lifting and lowering apparatus of claim 32,

wherein there is further provided the step of issuing a motion signal for selectably lifting

or lowering the lifting and lowering apparatus.