GB2623359A

GB2623359A - Battery powered cleaning device

Info

Publication number: GB2623359A
Application number: GB2215175.7A
Authority: GB
Inventors: John Blackledge Edward
Original assignee: Iic Products Ltd
Current assignee: Iic Products Ltd
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2024-04-17
Also published as: GB202215175D0

Abstract

A rotary floor cleaner (100) has a battery (128), a motor (130) driving a cleaning head and a controller (132) controlling delivery of power from the battery to the motor. The controller is configured, upon startup, to provide a soft start condition in which a reduced power is delivered to the motor. The soft start condition may be configured to switch to the running condition after a set period of time, or when the current supplied to the motor falls below a predetermined level. The cleaner may also comprise a DC/ DC converter configured to maintain a voltage to the motor during battery discharge. The output voltage to the motor may also be varied by a user control to be adaptable for different cleaning tasks. Also claimed is a battery powered cleaning device comprising a motor driving a cleaning actuator and a controller controlling delivery of power from the battery to the motor, wherein the controller is configured to maintain a voltage demand to the motor during battery discharge.

Description

Battery powered cleaning device

Technical Field

[0001] The present invention relates to a battery powered cleaning device. More specifically, the present invention relates to a human-propelled floor cleaner such as a scrubber, polisher, burnisher or vacuum cleaner having an on-board battery such as a lithium-ion battery pack.

Background Art

[0002] Various types of rotary floor cleaners are known in the art. They can generally be classified as either larger "walk behind" or "ride on" cleaners, or smaller human-propelled cleaners. The latter tend to have a main body with a cleaning head rotatably mounted thereto. A shaft extends from the body to a handle, allowing the user to push the device along the floor during operation. Controls are typically mounted on the handle. An electric motor drives the cleaning head in rotation, and by friction with the floor surface the head scrubs, polishes or burnishes the surface. The effect achieved depends on the type of head and the speed of rotation, with burnishers operating at the highest speed, and scrubbers at the lowest speed.

[0003] It is an aim of the invention to provide an improved cleaning device. Summary of Invention [0004] According to a first aspect of the present invention there is provided a rotary floor cleaner comprising: a battery; a motor driving a cleaning head; a controller controlling delivery of power from the battery to the motor; wherein the controller is configured, upon startup, to provide: a soft start condition in which a first power level is delivered to the motor; a running condition in which a second power level is delivered to the motor; in which the first power level is lower than the second power level.

[0005] Advantageously the soft start alleviates the problems associated with the immediate current draw. It allows the system to overcome the initial load (static friction) and to "spin up" in a controlled manner without damage to the battery or discomfort to the user.

[0006] Preferably in the soft start condition, the controller is configured to oscillate power to the motor between 0 and a first level. Preferably the oscillation has a mark space ratio of 1:1 -± 10%.

[0007] Preferably the soft start condition is configured to switch to the running condition after a set time period. Preferably the set time period is between 1 and 5 seconds.

[0008] Alternatively the soft start condition is configured to switch to the running condition when the current supplied to the motor falls below a predetermined level. The predetermined level may be between 20A and 50A.

[0009] Preferably a DC / DC converter is configured to maintain a voltage to the motor during battery discharge.

[0010] Preferably the output voltage to the motor can be varied by a user control to be adaptable for different cleaning tasks.

[0011] According to a second aspect of the present invention there is provided a battery powered cleaning device comprising: a battery; an electric motor driving a cleaning actuator; a controller controlling delivery of power from the battery to the actuator; wherein the controller is configured to maintain a voltage within a predetermined range of a voltage demand to the motor during battery discharge.

[0012] Preferably the controller is configured to maintain a voltage within 10% of the voltage demand to the motor during battery discharge.

[0013] Preferably the controller comprises a DC / DC converter configured to maintain the voltage to the motor during battery discharge.

[0014] Preferably the demand voltage can be varied by a user control such that the cleaner is adaptable for different cleaning tasks.

[0015] Preferably the actuator is one of a motor for a rotary cleaning head, a motor for an oscillating cleaning head, or a motor for a vacuum pump.

Brief Description of Drawings

[0016] An embodiment of the present invention will now be described with reference to the following figure in which: FIGURE 1 is a perspective view of a rotary floor cleaner; FIGURE 2 is a block diagram of the drive system of the cleaner of Figure 1; and. FIGURE 3 is a time plot of the power delivered to the cleaner of Figure 1. Description of the first embodiment [0017] Referring to Figure 1, a rotary floor cleaner 100 is shown having a body 102, an upright 104, a handle 106, a housing 108, a belt drive 110 and a driveboard 112.

[0018] The body 102 is a generally flat platform extending from a proximal end 114 (proximate the operator in use) to a distal end 116. A pair of wheels 115 are provided at the proximal end of the body 102.

[0019] Mounted to the body 102 is the upright 104. The upright 104 is a generally elongate member which is rotatable relative to the body 102 about a lateral axis Y, but resiliently urged into an upright position (per Figure 1) [0020] At the end of the upright 104 opposite to the body 102 there is provided the handle 106, forming a T-shape with the upright and defining two opposing handle bars 118, 120. The handle 106 is provided with on/off lever controls 122a, 122b a height adjustment control 124 and a solution dispenser control 126 for a cleaning solution reservoir (not shown). In use, the user can grip the handle bars 118, 120 to support and propel the cleaner 100 whilst operating the various controls.

[0021] The housing 108 contains a Li-ion battery 128, a motor 130 and a controller 132 (Figure 2). The controller 132 is configured to receive signals from the controls on the handle 106 and to control the flow of power from the battery 128 to the motor 130 to rotate an output shaft 134.

[0022] The output shaft 134 is connected to drive a pulley 136 contained within the belt drive 110. A belt 137 connects the pulley 136 to a driven pulley 138. The driven pulley 138 drives a driveboard receiving formation 140, which in turn is connected to the driveboard 112. The belt drive is a reduction gearbox, increasing the torque available at the driveboard.

[0023] The controller 132 comprises a PCB configured according to the present invention. Known rotary floor cleaners are mains powered, and are able to utilise direct on line motor starting. The controller 132 simply provides that the motor can draw as much current as required to maintain steady state operating voltage. In the present invention, such operation is problematic. The power required to initiate rotation of the drive board is significant, for several reasons, including: * Static friction between the driveboard cleaning material and the floor surface. This is typically much higher than the dynamic friction meaning that the startup power is very high compared to the operating power required. This occurs for several reasons, not least that floors can be tacky (due to dirt or prior cleaning substance residue) * The rotating components of the system (the motor rotor, belt drive and drive board) all have inertia that needs to be overcome.

[0024] It is also the case that application of maximum power to the motor at the outset is not ideal for useability. Electric motors have maximum torque at zero speed and given the amount of mechanical resistance in the system, the user needs to counteract this torque through the handle. Starting with a high level of instantaneous torque is therefore undesirable for comfortable operation.

[0025] Still further, Li-ion batteries like the battery 128 experience significant (circa 30%) voltage drops from a fully charged state to discharged. Because DC motor speed is proportional to the voltage across the terminals, this results in a significant and noticeable speed drop as the battery discharges. This has poor usability affects, as certain speeds are best for certain tasks and its harder to use the machine with a varying speed.

[0026] The PCB controller 132 is configured to detect incoming voltage (across the battery terminals). It then adaptively scales the voltage using a DC-DC converter, and outputs a voltage that varies far less than the natural variance of a Li-ion battery.

L0027] The PCB also provides speed control. A user control is provided (not showing) that facilitates speed control by adapting the voltage from the battery to the motor. This enables the machine to be used for multiple, different cleaning tasks.

[0028] Known voltage converters such as buck-boost converters may be used for such a controller.

[0029] Furthermore, the controller 132 is configured to utilise "soft start" when the machine is activated at zero speed. Rather than delivering full power to the motor with direct on line starting, the present invention starts by supplying a fraction of power to the motor 130 during a soft start condition time period Tst. Referring to Figure 3, this is achieved by switching the power supply with a mark space ratio of 1:1-i.e. power is supplied at a rate of 50%. This allows the driveboard 112 to build up speed more slowly (the oscillation is too high a frequency to be felt by the user, due to system inertia). After a period of Tst (in this embodiment 2.5s) the controller 132 provides continuous full power at condition Tss (steady state). By this time, the system is in motion and the static friction has been overcome. Therefore the current requirement of the motor will be lower, as will the load (and hence the torque the user needs to react). Referring to Figure 3 it can be seen that the current draw is initially high (although not as high as it would be if slow start was not employed). Once the steady state condition is engaged, the current has dropped below Cl.

[0030] The applicant has seen current spikes of 190A without the above "soft start" functionality-a current which would damage (or trip) the battery. The present invention limits the startup current to a more manageable 50A.

Variations [0031] Instead of a timed start condition (Tst), the current may be monitored and once it stays below e.g. Cl, the steady state condition is started. Although slightly more complex, such a system adapts to the load, and may require a longer startup for particularly high friction conditions.

[0032] The battery may be located in a different position, for example in, or attached to, the upright 104.

[0033] The cleaner may have multiple batteries connected to it (to gain more run time). The cleaner may also have multiple devices connected to it. For example, in addition to the rotary cleaning head: * a solenoid for controlled water dispensing; * a motor to provide vacuumation for either wet pickup, dry pick up or both.

[0034] Further motors may benefit from the soft start functionality. The afroementioned voltage control is advantageous to be applied to the ensure constant vacuumation. This would extend battery life by not needing to provide more than the required level of vacuumation during high battery voltage and ensure the machine still provides enough pressure difference to pick up during low battery voltage.

Claims

Claims 1. A rotary floor cleaner comprising: a battery; a motor driving a cleaning head; a controller controlling delivery of power from the battery to the motor; wherein the controller is configured, upon startup, to provide: a soft start condition in which a first power level is delivered to the motor; a running condition in which a second power level is delivered to the motor; in which the first power level is lower than the second power level.
2. A rotary floor cleaner according to claim 1, wherein in the soft start condition, the controller is configured to oscillate power to the motor between 0 and a first level.
3. A rotary floor cleaner according to claim 2, wherein the oscillation has a mark space ratio of 1:1 ± 10%.
4. A rotary floor cleaner according to any preceding claim, wherein the soft start condition is configured to switch to the running condition after a set time period.
A rotary floor cleaner according to claim 4, wherein the set time period is between 1 and 5 seconds
6. A rotary floor cleaner according to any of claims 1 to 3, wherein the soft start condition is configured to switch to the running condition when the current supplied to the motor falls below a predetermined level.
7. A rotary floor cleaner according to claim 6, wherein the predetermined level is between 20A and 50A.
8. A rotary floor cleaner according to claim 6, wherein the predetermined level is between 6A and 20A.
9. A rotary floor cleaner according to any preceding claim, comprising a DC / DC converter configured to maintain a voltage to the motor during battery discharge.
10. A rotary floor cleaner according to any preceding claim, wherein the output voltage to the motor can be varied by a user control to be adaptable for different cleaning tasks.
11. A battery powered cleaning device comprising: a battery; an electric motor driving a cleaning actuator; a controller controlling delivery of power from the battery to the actuator; wherein the controller is configured to maintain a voltage within a predetermined range of a voltage demand to the motor during battery discharge.
12. A battery powered cleaning device according to claim 11, wherein the controller is configured to maintain a voltage within 10% of the voltage demand to the motor during battery discharge.
13. A battery powered cleaning device according to claim 11 or 12, comprising a DC / DC converter configured to maintain the voltage to the motor during battery discharge.
14. A battery powered cleaning device according to any of claims 11 to 13, wherein the demand voltage can be varied by a user control such that the cleaner is adaptable for different cleaning tasks.
15. A battery powered cleaning device according to any of claims 11 to 14, wherein the actuator is one of a motor for a rotary cleaning head, a motor for an oscillating cleaning head, or a motor for a vacuum pump.