GB2546483A

GB2546483A - Road sweeping vehicle

Info

Publication number: GB2546483A
Application number: GB1600736.1A
Authority: GB
Inventors: Stock Jeff; Stock Mitch; Mark Pollock Anthony
Original assignee: Stock Sweepers Ltd
Current assignee: Stock Sweepers Ltd
Priority date: 2016-01-14
Filing date: 2016-01-14
Publication date: 2017-07-26
Anticipated expiration: 2036-01-14
Also published as: GB2546483B8; GB201600736D0; GB2546483B

Abstract

The road sweeping vehicle 100 comprises a debris suction mechanism 114 for removing material, e.g. dirt, litter, from a road surface. The road sweeping vehicle includes an alert system (154, figure 3) for detecting abnormal operation of the debris suction mechanism. Wherein the alert system comprises: a sensor (148, figure 3) arranged to detect an operating characteristic of the debris suction mechanism and output a detection signal that is indicative of the operating characteristic. Additionally, a controller (156, figure 3) is communicably connected to the sensor to receive the detection signal, the controller being arranged to: determine, based on the detection signal, if the debris suction mechanism is operating abnormally. Should the debris suction mechanism be operating abnormally then an alert notification is triggered. The invention also provides alert systems suitable for use in such vehicles.

Description

ROAD SWEEPING VEHICLE

The invention relates to road sweeping vehicles which have a suction device for removing material, e.g. dirt, litter or other debris, from a road surface.

Many types of road sweeping vehicle exist for the purpose of cleaning road or paved surfaces. Typically, such vehicles comprise a motorised debris collection mechanism mounted on a vehicle chassis, which is supported on a set of drivable wheels. The debris collection mechanism typically includes both a mechanical sweeping device, such as rotating brushes or the like, and a suction device, which may act to draw material into a collection chamber housed on the vehicle. Sweepers of this type are manufactured, for example, by Johnston Sweepers Limited and Scarab Sweepers Limited, and are well know to a person skilled in the art.

Typically, the suction device in a debris collecting mechanism includes an impeller which is driven to rotate by an auxiliary engine or motor. The impeller is normally a large object, e.g. having a diameter of 600 mm to 800 mm or more, and in operation can rotate at 3,800 rpm or more.

At its most general, the present invention provides a alert system for monitoring operation of a debris collecting mechanism in a road sweeper. In particular, the invention can detect abnormal rotation of an impeller in a suction device that is part of the debris collecting mechanism. In normal operation, the impeller is dynamically balanced on a shaft which is rotated by a suitable drive, such as an auxiliary engine or motor, typically via a step-up gearbox. If the impeller becomes imbalanced, i.e. its centre of mass moves substantially away from its axis of rotation, the suction mechanism can become damaged. The extent of damage can depend on the magnitude of the imbalance. For example, a minor imbalance may lead to increased wear on a bearing at the connection to the drive, e.g. in the motor or in the step-up gearbox. Minor imbalances may also cause fatigue cracks in the system components. If the imbalance is more significant, the damage can be catastrophic, e.g. tearing the step-up gear box off the auxiliary engine or even snapping the auxiliary engine crankshaft.

The suction mechanism on a road sweeper is normally located in the vicinity of the driver cab, e.g. behind the cab or on the cab roof. This means that a major breakage in the components carries a risk of driver injury.

Impeller imbalance can occur due to build up of dust or dirt on the impeller. During operation, dust and dirt will typically be deposited evenly over the entire surface of the impeller. However, if the impeller is not cleaned regularly, there is a risk that the layer of dust will fall off part of the impeller whilst remaining on other parts, and hence cause an imbalance.

Impeller imbalance can also occur if water enters the impeller intake passage. This may occur if the road sweeper is overloaded.

According to the invention, there is provided a road sweeping vehicle having: a chassis carried on a set of front and rear wheels; a debris suction mechanism supported on the chassis for generating an air flow path between an inlet suction port located between the front and rear wheels and an outlet exhaust port, whereby debris located around the inlet suction port is entrained in the air flow; a collection chamber on the flow path between the inlet suction port and the outlet exhaust port for receiving the entrained debris; and an alert system for detecting abnormal operation of the debris suction mechanism, wherein the alert system comprises: a sensor arranged to detect an operating characteristic of the debris suction mechanism and output a detection signal that is indicative of the operating characteristic, and a controller communicably connected to the sensor to receive the detection signal, the controller being arranged to: determine, based on the detection signal, if the debris suction mechanism is operating abnormally; and output an alert notification in response to a determination that the debris suction mechanism is operating abnormally.

The sensor may be arranged to transmit a continuous signal to the controller, or it may be polled by the controller, e.g. on a periodic basis. The controller may be arranged to determine regularly whether or not the debris suction mechanism is operating normally. On determining that operation is normal, the controller may take no action, i.e. no alert notification is needed. Alternatively, the controller may be arranged to output a signal indicating that operation is within expected parameters.

The sensor may be a vibration sensor. For example, the sensor may include a transducer for converting motion of the debris suction mechanism into an electrical signal.

The debris suction mechanism may be of a conventional type, e.g. comprising a rotatable impeller and a rotation drive connected to drive the rotatable impeller to cause air to flow rapidly along the air flow path from the inlet suction port to the outlet exhaust port. The vibration sensor may be mounted on the rotation drive. The rotation drive can be an auxiliary engine or motor. In one example, the rotation drive is an auxiliary engine connected to the impeller via a step-up gearbox. The vibration sensor may be mounted on the step-up gearbox.

The air flow path may be defined by a passageway, e.g. formed from flexible hosing or the like. The air flow path may be directed into the collection chamber in a manner to permit the entrained debris to drop from the flow of air.

This may be achieved in a conventional manner by widening the passageway for the air flow, which reduces its velocity. Alternatively or additionally a filtering or other separation device may be used.

The inlet suction port may comprise a suction nozzle or intake aperture. The inlet suction port may be located immediately rearwardly of a mechanical sweeping device, e.g. a cylindrical brush extending across the underside of the vehicle. One or more circular brushes (known as kerb or gutter brooms) may also be mounted between the front and rear wheels .

The suction mechanism discussed above is conventional, as described in GB 2 276 853, for example.

The sensor (e.g. vibration sensor) may be mounted on the step-up gear box, e.g. on a top plate thereof. The detection signal may be an electrical signal having a magnitude (of current or voltage) that is proportional to vibration velocity, i.e. the distance the mechanism moves per unit time (typically measured in units of mm/s).

The controller may be arranged to determine if the debris suction mechanism is operating abnormally by comparing the magnitude of the detection signal with a predetermined threshold. In order to prevent false alerts from being triggered, the controller may be arranged to obtain an average magnitude of the detection signal over a detection period.

The controller may be arranged to determine if the debris suction mechanism is operating abnormally by comparing the average magnitude of the detection signal with the predetermined threshold.

The alert system may be arranged to respond differently depending on the nature of the detected abnormality. For example, if the detected abnormality continues for longer than expected, or if the magnitude of the abnormality is beyond a second predetermined threshold that is indicative of danger, the controller may be arranged to output different types of alert notification. For example, the controller may be arranged to output an alert notification by transmitting a first alert command upon determining that the debris suction mechanism is operating abnormally for a first predetermined duration, and/or transmitting a second alert command upon determining that the debris suction mechanism is operating abnormally for a second predetermined duration, the second predetermined duration being longer than the first predetermined duration. The first alert command may be a simple warning for the operator, whereas the second alert command may change (e.g. limit) operation of the debris suction mechanism, e.g. by inhibiting operation of the auxiliary engine.

The chassis may support a driver cab above the front wheels. The driver cab may contain a display communicably connecter to the controller. The alert notification (e.g. first alert command) may be arranged to cause a change on the display. For example, the alert notification may cause a warning to be shown on the display, e.g. to tell the operator that the impeller needs to be cleaned.

The controller may be or may be part of (e.g. a module in) an engine control unit of the road sweeping vehicle. The alert notification (e.g. second alert command) may be arranged to cause a change in operation of the debris suction mechanism, e.g. by limiting operation of the auxiliary engine.

The controller may be arranged to monitor a torque demand and/or other behaviour of the auxiliary engine. This information may be used in addition to the detection signal to determining what type of alert notification is needed. Thus, the controller may be arranged to select an alert notification based on the torque demand and the detection signal. For example, the controller may be arranged to determine, based on the torque demand and detection signal, if the collection chamber is overloaded, and transmit an overload notification in response to a determination that the collection chamber is overloaded. The controller may be wirelessly connected to a remote location. The overload notification may comprise a message that is wirelessly transmitted to the remote location.

The alert system discussed above may be retrofitted to existing road sweeping vehicles. In another aspect, the invention therefore provides an alert system for detecting abnormal operation of a debris suction mechanism in a road sweeping vehicle, the alert system comprising: a sensor mountable on the debris suction mechanism and communicably connectable to an engine control unit of a road sweeping vehicle; and computer executable control instructions stored on a computer readable medium, the control instructions being for execution by the engine control unit, wherein the sensor operable to: detect an operating characteristic of the debris suction mechanism, and output a detection signal that is indicative of the operating characteristic, and wherein the control instructions are executable by the engine control unit to: determine, based on the detection signal, if the debris suction mechanism is operating abnormally; and output an alert notification in response to a determination that the debris suction mechanism is operating abnormally. Features of the alert system in the road sweeper discussed above are equally applicable in this aspect of the invention.

An embodiment of the invention is discussed below in more detail with reference to the accompanying drawings, in which:

Fig. 1 is a schematic side view of a road sweeping vehicle that is an embodiment of the invention; and

Fig. 2 is a schematic view of a vibration sensing arrangement that can be used in embodiments of the present invention; and

Fig. 3 is a schematic view of an impeller control system that can be used in embodiments of the present invention.

Fig. 1 shows a side view of a suction-type road sweeping vehicle 100 that is an embodiment of the invention. The vehicle 100 comprises a chassis 102 supported by a pair of front wheels 104 and a pair of rear wheels 106. A driver cabin 108 is mounted on the chassis 102 over the front wheels 104. The vehicle engine (not shown) is located under the driver cabin 108 and has an engine exhaust 110 mounted on the chassis 102 behind the driver cabin 108. Mounted on the chassis behind the engine exhaust 110 and driver cabin 108 is a container 112, which may be an airtight container, which contains a debris suction mechanism 114. To assist a description of the debris suction mechanism, the container 112 is made transparent in Fig. 1. In normal use the debris suction mechanism 114 would be not be visible in use.

The debris suction mechanism 114 comprises an impeller that is rotatable in fan housing 116 under the action of an auxiliary engine and gearbox (see Fig. 2). In operation, the impeller creates an air flow (indicated by arrows 118) through a passageway 120 inside the container 112 which draws air in from an inlet suction port 122 mounted on the chassis 102 between the front wheels 104 and rear wheels 106. The inlet suction port 122 may be an opening at the end of a flexible hose 124. The inlet suction port 122 is positioned behind (i.e. closer to the rear wheels 106 than) a mechanical sweeping mechanism 126 for disturbing debris on the road surface so that it is picked up in the air flow sucked into the inlet suction port 122. In this embodiment, the mechanical sweeping mechanism 126 includes a rotatable gutter broom 128 and a cylindrical brush 130.

The air flow from the inlet suction port 122 travels through the passageway 120 to a collection chamber 132 in the container 112. The passageway 120 widens into the collection chamber 132, which may encourage the debris entrained in the air flow to be deposited. Alternatively or additionally a filter (not shown) may be mounted in or at the entrance to the collection chamber 132, as is conventionally known.

The fan housing 116 includes an annular air flow passage which circulates the air flow from a central entrance aperture 134 connected to receive air from the passageway 120 to an exit aperture 136, which is connected to an exhaust passageway 138 that terminates at an outlet exhaust port 140 on the roof of the vehicle 100.

The road sweeping vehicle 100 shown in Fig. 1 is characterised by an alert system that can notify the operator (e.g. driver) and/or automatically take remedial action upon detecting that the debris suction mechanism is not operating within normal parameters. Abnormal operation may occur for example when the impeller becomes unbalanced about its rotation axis, or when the collection chamber 132 is overfilled, especially with water.

In one embodiment, the alert system comprises a vibration sensor that is arranged to detect vibration of the machinery associated with the impeller.

Fig. 2 is a schematic side view of the impeller drive components discussed above, to which the alert system of the invention can be applied. Fig. 2 shows the fan housing 116 that contains the impeller 142 (shown in dotted lines as it is contained within the fan housing 116). The impeller 142 is coupled via a step-up gearbox 146 to an auxiliary engine 144. The auxiliary engine 144 drives a shaft about a first drive axis 152, which is coupled, e.g. via a fluid coupling (not shown), to an input gear of the step-up gearbox 146. The input gear drives an output gear about second drive axis 150. The impeller 142 is connected to rotate with the output gear about second drive axis 150. A vibration sensor 148 is mounted to detect vibration in this drive system. In this example, the vibration sensor 148 is mounted on a top plate of the step-up gearbox 146. However, other suitable mounting position may be used.

The vibration sensor 148 can be any suitable device for detecting oscillating motion of the machinery and outputting a signal that is indicative of that vibration. For example, the vibration sensor may be arranged to detect vibration velocity (i.e. movement amplitude per second), e.g. by outputting an electric signal having a voltage or current whose amplitude corresponding to the magnitude of the vibration velocity. A VTV122 vibration transmitter manufactured by IFM Electronic GmbH can be used for this purpose.

The vibration sensor 148 may be directly attached, e.g. physically secured via a threaded connection or the like, to the top plate of the step-up gearbox 146. The signal output from the vibration sensor is conveyed via any suitable wired or wireless channel to a control system, which uses it to determine an appropriate response, as discussed below.

Fig. 3 shows a schematic view of an alert system 154 that can be used in the invention. The alert system 154 comprises the vibration sensor 148 mounted on the relevant machinery (not shown) within the road sweeper. The vibration sensor 148 is in communication with a controller 156, which can be any suitable engine control unit. Conventional engine control units comprises a processor and associated memory, which are arranged to execute engine management software. The alert system of the invention may be provided as an additional feature of such known control systems.

The controller 156 is in communication with an input/output device 158, which in this example includes a display. The input/output device 158 is arranged to communicate to the operator the current system status and to permit the operator to input control instructions. For example, the debris suction mechanism may be controlled via the input/output device 158. The controller 156 is in communication with the auxiliary engine 144. The auxiliary engine 144 therefore operates under the control of the controller 156.

The controller 156 may be arranged to monitor a signal received from the vibration sensor 148 to determine if the impeller is operating within normal parameters. In one example, the amplitude of current or voltage of the signal from the vibration sensor is indicative of vibration velocity. The controller 156 may compare the amplitude of the signal with a predetermined threshold to determine whether or not the impeller is operating normally. The vibration sensor 148 may provide a constant (analog) signal input to the controller 156. The controller 156 may take a series of readings of the constant signal input amplitude over a short period of time, and use an average of the series of readings for comparison with the predetermined threshold. This can minimise false alarms .

If the predetermined threshold is exceeded, the controller 156 can instruct a warning alert to be displayed on the input/output device 158. For example, the alert may instruct the operator to clean the impeller before continuing to operate the debris suction mechanism.

If the predetermined threshold is exceeded for longer than a predetermined duration, the controller 156 can impose restrictions on the operation of the auxiliary engine 144.

For example, the auxiliary engine 144 can be reduced to idle or otherwise limit the maximum torque that can be demanded. This can prevent damage that can arise from driving an unbalanced impeller. The controller 156 may be arranged to impose immediate restrictions on the auxiliary engine if the amplitude of the signal exceeds a second predetermined threshold, which may be indicative of dangerous levels of vibration.

The controller 156 may monitor other parameters. For example, the controller 156 may monitor the torque demand on the auxiliary engine together with the engine's response. The controller 156 may include logic that processes these parameters in combination with the signal from the vibration sensor to determine a status of the debris suction mechanism. For example, an abnormal vibration signal in combination with normal torque demand and engine response may indicate an unbalanced impeller. However, an abnormal vibration signal in combination with a mismatch between torque demand and engine response (e.g. a drop in engine speed for a given throttle demand) may indicate that water has entered the impeller, which can be a consequence of overfilling the collection chamber. The controller 156 may instruct a different response depending on whether the abnormal vibration indicates impeller imbalance or overfilling of the collection chamber.

The controller 156 may include a wireless communication module arranged to transmit notifications to a remote location. For example, the wireless communication module may be arranged to notify the remote location whenever the controller issues a warning alert or imposes restrictions on the auxiliary engine. The remote location may be the road sweeper depot or a central operation centre for the vehicle manufacturer or owner.

The alert system depicted in Fig. 3 may be suitable for retrofitting to existing road sweeper vehicles. A retrofit kit may comprise a vibration sensor, means for connecting the vibration sensor to an engine control unit in a road sweeper, and software instructions for uploading to the engine control unit of an existing road sweeper vehicle so that it is able to interpret an input signal from the vibration sensor in the manner described above.

Claims

1. A road sweeping vehicle having: a chassis carried on a set of front and rear wheels; a debris suction mechanism supported on the chassis for generating an air flow path between an inlet suction port located between the front and rear wheels and an outlet exhaust port, whereby debris located around the inlet suction port is entrained in the air flow; a collection chamber on the flow path between the inlet suction port and the outlet exhaust port for receiving the entrained debris; and an alert system for detecting abnormal operation of the debris suction mechanism, wherein the alert system comprises: a sensor arranged to detect an operating characteristic of the debris suction mechanism and output a detection signal that is indicative of the operating characteristic, and a controller communicably connected to the sensor to receive the detection signal, the controller being arranged to : determine, based on the detection signal, if the debris suction mechanism is operating abnormally; and output an alert notification in response to a determination that the debris suction mechanism is operating abnormally.

2. A road sweeping vehicle according to claim 1, wherein the sensor is a vibration sensor.

3. A road sweeping vehicle according to claim 2, wherein the debris suction mechanism comprises a rotatable impeller and a rotation drive connected to drive the rotatable impeller, wherein the vibration sensor is mounted on the rotation drive .

4. A road sweeping vehicle according to claim 3, wherein the rotation drive comprises a motor or an auxiliary engine .

5. A road sweeping vehicle according to claim 3 or 4, wherein the rotation drive includes a step-up gear box, and wherein the vibration sensor is mounted on the step-up gear box.

6. A road sweeping vehicle according to any one of claims 2 to 5, wherein a magnitude of the detection signal is proportional to vibration velocity, and wherein the controller is arranged to determine if the debris suction mechanism is operating abnormally by comparing the magnitude of the detection signal with a predetermined threshold.

7. A road sweeping vehicle according to claim 6, wherein the controller is arranged to obtain an average magnitude of the detection signal over a detection period, and wherein the controller is arranged to determine if the debris suction mechanism is operating abnormally by comparing the average magnitude of the detection signal with the predetermined threshold.

8. A road sweeping vehicle according to any preceding claim, wherein the controller is arranged to output an alert notification by transmitting a first alert command upon determining that the debris suction mechanism is operating abnormally for a first predetermined duration, and/or transmitting a second alert command upon determining that the debris suction mechanism is operating abnormally for a second predetermined duration, the second predetermined duration being longer than the first predetermined duration.

9. A road sweeping vehicle according to any preceding claim, wherein the chassis supports a driver cab above the front wheels, wherein the driver cab contains a display communicably connecter to the controller, and wherein the alert notification is arranged to cause a change on the display.

10. A road sweeping vehicle according to any preceding claim, wherein the controller is an engine control unit of the road sweeping vehicle, and wherein the alert notification is arranged to cause a change in operation of the debris suction mechanism.

11. A road sweeping vehicle according to claim 10, wherein the debris suction mechanism comprises a rotatable impeller and an auxiliary engine connected to drive the rotatable impeller, and wherein the alert notification is arranged to limit operation of the auxiliary engine.

12. A road sweeping vehicle according to claim 11, wherein the controller is arranged to monitor a torgue demand of the auxiliary engine, and wherein the controller is arranged to select an alert notification based on the torque demand and detection signal.

13. A road sweeping vehicle according to claim 12, wherein the controller is further arranged to: determine, based on the torque demand and detection signal, if the collection chamber is overloaded, and transmit an overload notification in response to a determination that the collection chamber is overloaded.

14. A road sweeping vehicle according to claim 13, wherein the controller is wirelessly connected to a remote location, and wherein the overload notification comprises a message that is wirelessly transmitted to the remote location.

15. An alert system for detecting abnormal operation of a debris suction mechanism in a road sweeping vehicle, the alert system comprising: a sensor mountable on the debris suction mechanism and communicably connectable to an engine control unit of a road sweeping vehicle; and computer executable control instructions stored on a computer readable medium, the control instructions being for execution by the engine control unit, wherein the sensor operable to: detect an operating characteristic of the debris suction mechanism, and output a detection signal that is indicative of the operating characteristic, and wherein the control instructions are executable by the engine control unit to: determine, based on the detection signal, if the debris suction mechanism is operating abnormally; and output an alert notification in response to a determination that the debris suction mechanism is operating abnormally.

16. An alert system according to claim 15, wherein the sensor is a vibration sensor.