ISOLATION FOR WORK MACHINE ELECTRICAL CONNECTORS

A work machine includes a power source, a plurality of connectors, and an isolator circuit. The power source is configured to provide power to an electrical system of the work machine. The plurality of connectors are for electrically connecting external components to the work machine and are configured to receive power from the power source. The isolator circuit is connected between at least one of the plurality of connectors and the electrical system of the work machine to selectively terminate power to the at least one of the plurality of connectors while the power source is providing power to the electrical system of the work machine.

TECHNICAL FIELD

The present application relates generally to electrical systems. More particularly, the present application relates to electrical isolation for electrical components of work machines.

BACKGROUND

Paving machines are used to grind out, apply, spread and compact paving material relatively evenly over a desired surface. These machines are regularly used in the construction of roads, parking lots and other areas where a smooth durable surface is required for cars, trucks and other vehicles to travel. When a crew arrives at a paving machine and/or cold planer, the crew often starts the machine to warm up the cold planer, the paver, and a screed. While the machines are warming up, external components may be plugged in and/or swapped out for use during operation of the machine.

WO 2011135846 A1 discusses an electrical system for an asphalt finisher that includes a changeover switch for changing between primary power of the asphalt finisher and a secondary, external, power source.

SUMMARY OF THE INVENTION

In one example, a work machine includes a power source, a plurality of connectors, and an isolator circuit. The power source is configured to provide power to an electrical system of the work machine. The plurality of connectors are for electrically connecting external components to the work machine and are configured to receive power from the power source. The isolator circuit is connected between at least one of the plurality of connectors and the electrical system of the work machine to selectively terminate power to the at least one of the plurality of connectors while the power source is providing power to the electrical system of the work machine.

In another example, a method of electrical isolation for a work machine includes powering, via a power source, an electrical system of the work machine; controlling an isolator circuit to terminate power to at least one of a plurality of connectors from the electrical system of the work machine; changing a connected state of at least one component with respect to the at least one of the plurality of connectors; and controlling the isolator circuit to reconnect power to the at least one of the plurality of connectors from the electrical system.

In another example, an electrical system of a work machine includes a machine electrical system, a plurality of connectors, and an isolator circuit. The machine electrical system is connected to receive power from a power source of the work machine. The plurality of connectors are for electrically connecting and disconnecting detachable components to the work machine and are configured to receive power from the machine electrical system. The isolator circuit is connected between at least one of the plurality of connectors and the machine electrical system to selectively terminate power to the at least one of the plurality of connectors while the power source is providing power to the machine electrical system.

DETAILED DESCRIPTION

FIGS. 1A-1Care block diagrams illustrating work machines, specifically paving machines100A-100C, having electrical systems that include one or more isolator circuits. While described below with respect to paving machines, also known as pavers, and cold planer machines, any other work machines, including compactors, mixers, scrapers, dozers, excavators, material haulers, and other example machine types may include the systems and methods described herein.

FIG. 1Ais a block diagram illustrating an example electrical system for a paving machine100A. The paving machine100A includes at least a tractor102and a screed104. The paving machine100A can include any additional components not illustrated inFIG. 1A. The tractor102includes machine power106, tractor electrical system108, an isolator circuit110, connectors112A-112D, and external components114A-114D. The screed104includes screed electrical system116, connectors118A-118F, and external components120A-120F. The screed electrical system116is connected to the isolator circuit110through an electrical connector122, such as a wiring harness, for example,

The paving machine100A may be used to spread and compact paving material relatively evenly over a desired surface. The paving machine may include a hopper, for example, for receiving asphalt material from a truck and a conveyor system for transferring the asphalt rearwardly from the hopper for discharge onto a roadbed. Screw augers may be used to spread the asphalt transversely across the roadbed in front of a screed plate. The screed plate smooths and somewhat compacts the asphalt material to leave a roadbed of uniform depth and smoothness.

The machine power106may be generated using one or more power sources such as a prime mover of the paving machine100A, one or more backup power sources, and/or one or more external power sources. For example, the paving machine100A may include an internal combustion engine, such as a diesel engine, an electric motor powered by a battery pack, or another engine type. In an example, in internal combustion engine may include one or more attached generators configured to convert mechanical energy from the engine into electrical energy for use by the paver electrical systems. In other examples, the machine power106may be received from one more backup power sources including batteries, capacitors, external power sources, and the like in addition to, or in place of, the primary power source.

The tractor electrical system108may encompass the electrical wiring and/or other electrical components of the tractor102to distribute electrical power from the machine power106to the isolator circuit110and other machine electrical components. For example, the paving machine100A may include one or more control systems that include controllers, processors, and/or other components that receive and use electrical power. In one example, a single wire or wire harness may be used to carry electrical power from the machine power106to the isolator circuit110. In conventional paving systems, the tractor electrical system108distributes power from the machine power106directly to the plurality of connectors112A-112D. The screed electrical system116may encompass the electrical wiring and/or other electrical components of the screed104to distribute electrical power received through the electrical connector122.

In conventional paver machines, power is received by the connectors112A-112D and118A-118F any time the engine of the paving machine is running and the tractor electrical system108is receiving power. When a crew arrives at a paving machine, it is desirable to start the engine to warm up the paving machine and also warm up the screed. While the machine is warming up, the crew plugs in and/or unplugs the components114A-114D from the connectors112A-112D. In conventional systems, because the engine is running and the machine is warming up, power is being provided to the connectors112A-112D and118A-118F.

The components114A-114D and120A-120F may be sensors, controls, and the like. For example, the tractor components114A-114D may include left and right auger height sensors, left and right conveyor height sensors, and the like. The components120A-120F may include left and right material height sensors, left and right grade sensors, pendant controls, and the like. The components114A-114D and120A-120F may also include any other sensors, controls, or other electrical components capable of connecting to the tractor102and/or the screed104through the connectors112A-112D and/or118A-118F.

The connectors112A-112D and118A-118F may be configured in any way to provide electrical power to the components114A-114D and120A-120F. In an example, the connectors may be male- or female-type connectors, and may include any number of pins or other electrical connections including, for example, a power connection and a ground connection. When plugging components into the connectors112A-112D and118A-118F, if the power line is hot, arcing may occur, which can cause damage to the component, the connector, and/or blow fuses of the electrical system of the tractor102or screed104.

The isolator circuit110is configured to disconnect and isolate the connectors112A-112D and118A-118F from the machine power106. The isolator circuit110may include one or more isolator switches which may be mechanical, electrical, or electro-mechanical, in an example, a single isolator switch may be used to provide isolation for all connectors112A-112D and118A-118F. The isolator switch(es) may be manually operable such that an operator of the paving machine100A may manually terminate power to the connectors112A-112D and118A-118F when connecting/disconnecting any of the components114A-114D and/or120A-120F and then manually reconnect power to the connectors112-112D and118A-118F. This way, the machine power106can remain on, allowing connection/disconnection of components114A-114D and120A-120F while the paving machine100A is warming up. In other examples, the isolator circuit110may be controllable through one or more electronic control inputs. For example, an input/output (IO) device located on the paving machine100A, such as at an operator control station, may receive input from an operator to control a state of a respective switch of the isolation circuit110.

FIGS. 1B and 1Cillustrate additional example paving machines100B and100C, respectively. Instead of the isolator circuit110illustrated inFIG. 1A, the paving machine100B includes separate isolator circuits130and132. The isolator circuit130is connected between the tractor electrical system108and the connectors112A-112D and the isolator circuit132is connected between the screed electrical system116and the connectors118A-118F. Each isolator circuit130and132may include one or more mechanical or electrical switches, for example, manually or electronically controllable to selectively connect and terminate power to and from the tractor electrical system108and the screed electrical system116, respectively.

The isolator circuit130may be physically positioned on the tractor102and the isolator circuit132may be physically positioned on the screed104, for example. This way, if an operator of the paving machine100B wishes to only connect/disconnect one of the components120A-120F, the operator can control the isolator circuit132, which may be positioned on the screed104, near the connectors118A-118F, rather than needing to control an isolator circuit positioned physically on the tractor102. While illustrated as connected between the screed electrical system116and the connectors118A-118F, the isolator circuit132may also be connected between the electrical connector122and the screed electrical system116, for example.

The paving machine1000, as illustrated inFIG. 1C, includes isolator circuits140A-140D and142A-142F. While illustrated as having a 1:1 relationship with the connectors112A-112D and118A-118F, the paving machine100C may include any number of isolator circuits140A-140D and142A-142F. The isolator circuits140A-140D and142A-142F may each include one or more electrical or mechanical switches configured to selectively terminate power to the connectors112A-112D and118A-118F from the tractor electrical system108and the screed electrical system116, respectively. Each isolator circuit140A-140D and142A-142F may be positioned on the tractor102or screed104in a position relatively close to a respective connector112A-112D and118A-118F. This way, an operator that wishes to connect or disconnect a specific component114A-114D or120A-120F can quickly and easily locate the isolator circuit for the respective component.

FIG. 2is a block diagram illustrating an example electrical system for a cold planer machine200. The cold planer machine200, also referred to as a milling machine, includes machine power202, planer electrical system204, an isolator circuit206, connectors2084-208F, and external components210A-210F. The cold planer machine200may be used to process paving material, such as by scarifying, removing, or reclaiming such material from the surface of a paved road. These machines can include a frame having a rotary cutting tool for processing the paving material, and two or more tracks or wheel units for propelling the cold planer machine200forward. The two or more tracks or wheel units can be coupled to the frame of the cold planer machine200using extendable struts that can be adjusted (e.g., extended or retracted) to raise or lower the frame of the cold planer machine200, such as to control the depth at which the cold planer machine200cuts into a surface or road.

The machine power202may be generated using one or more power sources such as a prime mover of the cold planer machine200, one or more backup power sources, and/or one or more external power sources. For example, the cold planer machine may include an internal combustion engine, such as a diesel engine, an electric motor powered by a battery pack, or another engine type. The planer electrical system204may encompass the electrical wiring and/or other electrical components of the cold planer machine200to distribute electrical power from the machine power202to the isolator circuit206and other machine electrical components. In one example, a single wire or wire harness may be used to carry electrical power from the machine power202to the isolator circuit206.

In conventional cold planer machines, power is received by the connectors208A-208F any time the engine is running and the planer electrical system204is receiving power. When a crew arrives at a cold planer machine, it is desirable to start the engine to warm up the cold planer machine. While the machine is warming up, the crew plugs in and/or unplugs the components210A-210F from the connectors208A-208F. in conventional systems, because the engine is running and the machine is warming up, power is being provided to the connectors208A-208F.

The components210A-210F may be sensors, controls, and the like. For example, the components210A-210F may include grade sensors, pendant controls, and the like. The connectors208A-208F may be configured in any way to provide electrical power to the components210A-210F. In an example, the connectors may be male- or female-type connectors and may include any number of pins or other electrical connections including, for example, a power connection and a ground connection. When plugging components into the connectors208A-208F, if the power line is hot, arcing may occur, which can cause damage to the component, the connector, and/or blow fuses of the electrical system of the cold planer machine200.

The isolator circuit206is configured to disconnect and isolate the connectors208A-208F from the machine power202. The isolator circuit206may include one or more isolator switches which may be mechanical, electrical, or electro-mechanical. In an example, a single isolator switch may be used to provide isolation for all connectors208A-208F, The isolator switch(es) may be manually operable such that an operator of the cold planer machine200may manually terminate power to the connectors208A-208F when connecting/disconnecting any of the components210A-210F and then manually reconnect power to the connectors208A-208F. This way, the machine power202can remain on, allowing connection/disconnection of components210A-210F while the cold planer machine200is warming up. In another example, several separate isolator switches may be connected between each connector2084-208F and the planer electrical system204.

FIG. 3is a flowchart illustrating an example method300of isolating electrical components for a work machine. At step302, power is turned on for the work machine. This may be accomplished by starting an engine of the work machine, for example. Electrical energy may be generated using the mechanical energy generated by the engine and provided to an electrical system of the work machine. At step304, an isolator circuit, such as the isolator circuit110, is controlled to terminate power to all electrical connectors of the work machine that allow connection or disconnection of external components, such as external sensors, controls, and the like. In an example, the work machine may be a paving machine and include connectors on both a tractor portion of the paving machine and a screed portion. Power may be terminated to connectors on both portions of the paving machine. In another example, the work machine may be a cold planer machine.

At step306, while power is terminated to the connectors, an operator of the work machine changes the connection state of at least one of the external components with respect to the connectors. This may include connecting a component to the work machine and/or disconnecting a component from the work machine. By changing the connection state while power is disconnected from the connectors, the risk of damage to the components and/or the work machine electrical system is reduced. At step308, following connection or disconnection of the components, the isolator circuit is controlled to reconnect power to all connectors of the work machine from the machine electrical system.

FIG. 4is a flowchart illustrating another example method400of isolating electrical components for a paving machine that includes a tractor portion and a screed portion. At step402, power is turned on for the paving machine. This may be accomplished by starting an engine of the paving machine, for example. Electrical energy may be generated using the mechanical energy generated by the engine and provided to an electrical system of the work machine. At step404, an isolator circuit, such as the isolator circuit130, is controlled to terminate power to electrical connectors of the tractor portion of the paving machine that allow connection or disconnection of external components, such as external sensors, controls, and the like.

At step406, while power is terminated to the connectors of the tractor portion, an operator of the paving machine changes the connection state of at least one of the external components with respect to the tractor connectors. This may include connecting a component to the tractor and/or disconnecting a component from the tractor. By changing the connection state while power is disconnected from the connectors, the risk of damage to the components and/or the tractor electrical system is reduced. At step408, following connection or disconnection of the components, the isolator circuit130is controlled to reconnect power to all connectors of the tractor portion from the tractor electrical system,

At step410, an isolator circuit, such as the isolator circuit132, is controlled to terminate power to electrical connectors of the screed portion of the paving machine that allow connection or disconnection of external components, such as external sensors, controls, and the like. At step412, while power is terminated to the connectors of the screed portion, an operator of the paving machine changes the connection state of at least one of the external components with respect to the screed connectors. This may include connecting a component to the screed and/or disconnecting a component from the screed. By changing the connection state while power is disconnected from the connectors, the risk of damage to the components and/or the screed electrical system is reduced. At step414, following connection or disconnection of the components, the isolator circuit132is controlled to reconnect power to all connectors of the screed portion from the screed electrical system.

INDUSTRIAL APPLICABILITY

In one illustrative example, a paving machine, such as a Caterpillar AP355F Paver, includes several external components that can be plugged into/unplugged from the paver and/or screed. For example, left and right auger height sensors and left and right conveyor height sensors can be plugged into the tractor of the paver. Left and right material height sensors, two grade sensors, and two pendant controls can be plugged into a screed connected to the paver. When a crew arrives at the paver, the crew may start the engine to warm up the paver and also warm up the screed heater. During this time, the crew plugs in and/or unplugs external devices as desired. Prior to performing these actions, one or more isolation circuits are controlled to terminate power from the paver electrical system to the connectors for the external devices. Once the power is terminated to the connectors, the external devices are plugged in or unplugged. Following connection/disconnection of the external devices, the isolation circuits are controlled to resupply power to the external components for use during operation of the paver.