WO2024062402A1

WO2024062402A1 - A castor control system

Info

Publication number: WO2024062402A1
Application number: PCT/IB2023/059323
Authority: WO
Inventors: Angus Donald Ross Mcleod; Anthony John Batley
Original assignee: Howard Wright Limited
Priority date: 2022-09-21
Filing date: 2023-09-21
Publication date: 2024-03-28

Abstract

The invention provides a castor control system for a wheeled apparatus having a chassis with a plurality of castors adapted to operate in at least two different operating modes, including a brake mode. The castor control system includes: a rotatable toggle that is operably engageable with a rotatable driven element driven by a motor to enable the toggle to rotate between at least two different positions by operation of the motor, and a transmission system comprising a transmission link, a first control element, and a first transmission lever. The driven element is rotatable by the motor in a first direction to cause the toggle and the driven element to rotate to a first position, and the driven element is also rotatable by the motor in a second direction, opposite to the first direction, to adopt a neutral position after the toggle reaches the first position. The toggle is rotatably connected to the transmission link, to move the transmission link in opposing first and second directions upon rotation of the toggle by operation of the motor. The transmission link is operably connected to a first control element that engages with at least one castor and comprises a major axis about which the control element is rotatable. At least one pedal is fixedly connected to the control element and is rotatable between positions corresponding to the different operating modes of the castors. When the driven element is in the neutral position, manual operation of the pedal causes rotation of the toggle without engaging the motor.

Description

A CASTOR CONTROL SYSTEM

FIELD OF INVENTION

This invention relates to a castor control system for a wheeled apparatus, such as a hospital or nursing care bed, a stretcher, trolley, or any other apparatus comprising electrically, or mechanically controllable castors to assist with steering and braking.

BACKGROUND

It is common for a wheeled apparatus to comprise a chassis mounted on castors. The castors can be changed between different operating modes electrically (by a powered motor or linear actuator) and manually (by pedals). However, under electrical operation, there is a risk that power to the motor may be lost or the motor may fail. If this occurs when the castors are in brake mode, the wheeled apparatus can become difficult to maneuver. In some scenarios, the wheeled apparatus may comprise a patient transport apparatus, such as a hospital bed or stretcher, and may become stuck in brake mode at an inconvenient location, such as in a corridor or elevator.

Therefore, castor control systems have been developed to allow for the castors to be manually released from brake mode. However, such systems may require a user to manually change the operating mode of the castor by operating a particular pedal, which may not be easily accessible. Other known systems, require a user to engage a tool to release the castors from brake mode. The user typically has to engage the tool at the lower portion of the chassis nearthe castors. If the wheeled apparatus is a hospital bed, for example, that is locked in brake mode on a slope and the user needs to engage the tool with the lower, downhill side of the chassis then the user is at risk of being hit by the bed once the brake is released and the bed is free to move downhill. Such existing castor control systems may provide inconvenient and / or unsafe solutions to manually unlocking castors in brake mode.

PCT patent publication no. WO2021/138176 discloses an electro-mechanical braking system for a patient transport apparatus adapted to enable a person to selectively engage or disengage brakes associated with castors of the apparatus. Brakes on each side of the apparatus are linked via first links, which are linked to each other via second links to form a linkage, so that brakes for all four castor assemblies may be braked simultaneously. Coupling links connect the first and second links. An electric drive link couples an electric brake and release system to the first and second links. A sector gear with teeth is adapted to mate with teeth of a corresponding engagement slot in the second link, so that rotation of the sector gear causes reciprocating movement of the second link and consequently, the first link to brake or release the castors. However, to manually brake or release the castors, the motor may need to be back-driven under this arrangement. Therefore, it may be useful to provide a castor control system that goes at least some way towards overcoming the disadvantages of the prior art, or that at least provides the public with a useful alternative.

SUMMARY OF INVENTION

In a first aspect, the invention provides an electro-mechanical castor control system for a wheeled apparatus comprising a frame supported by a chassis comprising a plurality of castors adapted to be operated electrically and mechanically in at least two different operating modes, including a brake mode. The castor control system comprises: a rotatable toggle that is operably engageable with a rotatable driven element driven by a motor to rotate the toggle between at least two different positions, selectable by a user via a user interface, and a transmission system comprising a transmission link, a first control element, and a first transmission lever. The toggle is rotatably connected to the frame or chassis and to the transmission link, to slidably move the transmission link in opposing first and second directions upon rotation of the toggle. The first control element is operably engaged with at least one castor and comprising a major axis about which the control element is rotatable to change the operating mode of the at least one castor. The first transmission lever is rotatably connected to the transmission link and fixedly connected to the first control element to translate movement of the transmission link to rotational movement of the first control element and vice versa. At least one pedal is fixedly connected to the first control element and is rotatable between positions corresponding to the different operating modes of the castors. The driven element is supported by the frame or chassis and is rotatable by the motor in a first direction to reach a first position, and in a second direction to reach a neutral position. The driven element comprises a body comprising an opening at least partially defined by a pair of contact surfaces between which at least a portion of the toggle is located. The castor control system further comprises: at least one sensor adapted to sense whether the driven element has reached the first position or the neutral position; and a programmable controller adapted to receive a user input via the user interface to operate the motor to rotate the driven element in the first direction according to the received user input, and to receive signals from the at least one sensor to cause the motor to rotate the driven element in a second direction, opposite to the first direction, once the at least one sensor signals that the driven element has reached the first position. The controller is programmed to stop the motor once the at least one sensor signals that the driven element has reached the neutral position, in which the toggle is located substantially centrally between the contact surfaces of the driven element and is spaced from each of the contact surfaces of the driven element, and in which manual operation of the pedal allows rotation of the first control element without engaging the motor.

In some forms, the motor is back-driveable such that when both the toggle and driven element are in the first position, manual operation of the pedal causes rotation of the control element by back- driving the motor.

In some forms, the first control element comprises an engagement feature that engages with an engagement feature of the first transmission lever to prevent rotation of the control element relative to the first transmission lever.

In some forms, the control element comprises a rod comprising a non-circular lateral crosssection and the first transmission lever comprises a correspondingly shaped opening for snugly receiving a portion of the first control element therein to prevent rotation of the first control element relative to the first transmission lever.

In some forms, the chassis comprises three castors and the castor control system comprises a second control element and a second transmission lever, each of the first and second control elements being connected to the transmission link by a respective one of the first and second transmission levers. The first control element is operably engaged with two opposing ones of the castors and the second control element is operably engaged with another one of the castors.

In some forms, the chassis comprises four castors and each control element is operably engaged with two opposing ones of the castors.

Optionally, at least one pedal is fixedly connected to each control element, such that rotation of the control elements causes simultaneous rotation of the pedals, and rotation of at least one ofthe pedals causes simultaneous rotation of the control elements and all of the pedals.

In some forms, each transmission lever is rotatably connected to the transmission link at or near a distal end of the transmission link and the toggle is rotatably connected to the transmission link at a location between the transmission levers.

In some forms, the driven element comprises a substantially C-shaped body having a substantially central opening within which a first end of the rotatable toggle is located, the first end of the toggle and the driven element being independently rotatable about a single axis; and the toggle comprises an arm extending from the first end and terminating at a second end of the toggle, the second end of the toggle being rotatably connected to the transmission link.

In some forms, the substantially C-shaped body of the driven element comprises terminal ends adapted to press against the rotatable toggle to rotate the toggle from one position to another.

Optionally, the driven element and the toggle are each rotatable between at least two positions.

In some forms, the driven element is rotatable between at least three positions, comprising a neutral position; a second position; and a third position, and the toggle is rotatable between at least two of the three positions.

In some forms, the driven element and the toggle are each rotatable between three positions.

Optionally, the toggle rotates between about 30° and about 60° between two of the three positions.

In some forms, when the driven element is in the neutral position, contact surfaces of the driven element are spaced from the toggle at a distance to allow the toggle to rotate between positions without contacting the driven element.

In some forms, a first position of the toggle corresponds to a brake mode of the castors, a second position of the toggle corresponds with a drive mode of the castors, and a neutral position of the toggle corresponds to a neutral mode of the castors.

In some forms, the castor control system further comprises a controller adapted to receive a user input relating to a selected operating mode via the user interface to change the operating mode of the castors, and to cause the motor to rotate the driven element to press against and rotate the toggle to a position that corresponds with the selected operating mode.

In some forms, the controller is programmed to reverse operation of the motor to cause the driven element to return to the neutral position after the toggle reaches a position corresponding to a selected operating mode.

In some forms, the motor and at least a portion of the driven element and toggle are located in a housing together with a second motor for independently powering an electric drive wheel attached to the chassis.

In some forms, the castor control system comprises a gear system comprising a drive gear, rotatable in a clockwise direction and in an anti-clockwise direction by the motor; and the driven element is directly or indirectly engaged by the drive gear to rotate in an anti-clockwise direction and in a clockwise direction, the rotatable driven element being adapted to urge the rotatable toggle from one position to another.

Optionally, at least a portion of a circumferential surface of the driven element comprises teeth to mesh with teeth of the drive gear.

In a second aspect, the invention provides a castor control system for a chassis comprising a plurality of castors. The castor control system comprises: an actuation system comprising a motor operable by a controller and operably engaged with a drive system; and a transmission system comprising a first rotatable control element comprising a major axis about which the control element is rotatable, the first control element being operably engaged with the castors, and the transmission system further comprising at least one pedal fixedly connected to the first control element and being moveable between different positions. The transmission system is adapted to transmit rotational output from the motor into rotation of the first control element to change the operating mode of the castors. The drive system is adapted such that, by moving the at least one pedal from a first position to a second position, the first control element is rotated without engaging the motor, to manually change the operating mode of the castors.

In some forms, the at least one pedal is adapted to rotate between a brake position, a drive position, and a neutral position, and each of the brake, drive and neutral positions of the at least one pedal respectively correspond with a brake mode, a drive mode, and a neutral mode of operation of the castors.

In a third aspect, the invention provides a wheeled apparatus comprising a chassis comprising a plurality of castors and a castor control system of the first or second aspects of the invention.

Optionally, the wheeled apparatus comprises a patient transport apparatus or a trolley.

In a fourth aspect, the invention provides a chassis comprising a plurality of castors and a castor control system of the first or second aspects of the invention.

In a fifth aspect, the invention provides a method of operating the castor control system of the first or second aspects to the invention, to override the reversible motor when the castors are in a first mode, the method comprising moving at least one pedal of the castor control system from a first position to a second position, to rotate the at least one control element to cause the castors to adopt a second operating mode.

In a sixth aspect, the invention provides a castor control system comprising: a linkage arrangement comprising a plurality of linked members, the linkage arrangement being connected to a plurality of castors attached to a chassis of a wheeled apparatus; and an actuation system connected to the linkage arrangement to move the linkage arrangement between a first position and a second position to change an operating mode of the castors. The actuation system comprises a motor, an actuator, a controller, and a user interface, the user interface being connected to the controller, and the controller being adapted to operate the motor according to inputs received via the user interface. The actuator is operable by the motorto rotate between a first position and a second position, and the rotatable actuator is adapted to engage with a toggle that is rotatably attached to at least one of the linked members to move the linkage between the first and second positions as the actuator rotates.

Optionally, the linkage arrangement comprises a transmission link, a first transmission lever, and a first control element comprising a major axis and being rotatable about its major axis. The first transmission lever is rotatably connected to the transmission link and fixedly connected to the first control element. The first control element is operably engaged with at least one of the castors such that rotation of the first control element changes the operating mode of the at least one castor, and the first transmission lever forms the toggle that engages with the actuator.

In some forms, the linkage arrangement comprises a transmission link, a first transmission lever, and a first control element comprising a major axis and being rotatable about its major axis. The first transmission lever is rotatably connected to the transmission link and fixedly connected to the first control element. The first control element is operably engaged with at least one of the castors such that rotation of the first control element changes the operating mode of the at least one castor, and the toggle is rotatably connected to the transmission link.

In some forms, the actuator comprises a body comprising an opening at least partially defined by a pair of substantially opposing contact surfaces. At least a portion of the rotatable toggle is located within the opening and between the contact surfaces. When the actuator rotates, one of the contact surfaces of the actuator contacts the toggle, so that the toggle is caused to rotate.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred examples of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

Figure 1 is an isometric, partially exploded view of one form of chassis of a wheeled apparatus in the form of a hospital bed that comprises one form of castor control system of the present invention;

Figure la is an isometric view of one form of castor control system of the invention;

Figure 2 is a schematic representation of one form of castor control system of the invention when employed with a generic chassis for a wheeled apparatus and that allows for operation of the castors in three different modes, the castor control system being shown in a neutral mode;

Figure 2a is an enlarged view of the castor control actuation system of Figure 2;

Figure 2b is an enlarged view of the castor control actuation system of Figure 2 and that also shows a schematic representation of a possible arrangement of sensors according to one embodiment;

Figure 2c is a schematic front view of another form of toggle and driven element that may be used with the castor control system of the invention;

Figure 2D is a schematic front view of yet another form of toggle and driven element that may be used with the castor control system of the invention; Figure 3a is a schematic representation of one form of castor control system of the invention in which the operating mode has been electrically changed from a neutral mode to a brake mode by changing the toggle position from a neutral position to a brake position;

Figure 3b is a schematic representation of the castor control system of Figure 3a in which the driven element has been rotated to a centred / home / neutral position after the toggle has reached the brake position;

Figure 4a is a schematic representation of the castor control system of Figure 3a in which the operating mode has been electrically changed from a brake mode to a neutral mode by changing the toggle position from a brake position to a neutral position;

Figure 4b is a schematic representation of the castor control system of Figure 4a in which the driven element has been rotated to a centred / home / neutral position after the toggle has reached the neutral position;

Figure 5a is a schematic representation of the castor control system of Figure 3a in which the operating mode has been electrically changed from a neutral mode to a drive mode by changing the toggle position from a neutral position to a drive position;

Figure 5b is a schematic representation of the castor control system of Figure 5a in which the driven element has been rotated to a centred / home / neutral position after the toggle has reached the drive position;

Figure 6a is a schematic representation of the castor control system of Figure 3a in which the operating mode has been electrically changed from a drive mode to a neutral mode by changing the toggle position from a drive position to a neutral position;

Figure 6b is a schematic representation of the castor control system of Figure 6a in which the driven element has been rotated to a centred / home / neutral position after the toggle has reached the neutral position;

Figure 7 is a schematic representation of another form of castor control system of the invention that allows for the castors to be operated in just two different modes and in which the toggle is shown in a first position, such as a brake position;

Figure 8a is a schematic representation of the castor control system of Figure 7 in which the toggle is shown in a second position, such as a neutral position or a brake position;

Figure 8b is a schematic representation of the castor control system of Figure 8a in which the driven element has been rotated to a centred / home / neutral position after the toggle has reached the second position;

Figure 9a is a schematic representation of another form of castor control system that allows for the castors to be operated in just two different modes and in which the operating mode of the castor control system has been electrically changed from a brake mode to a drive mode by changing the toggle position from a brake position to a drive position;

Figure 9b is a schematic representation of the castor control system of Figure 9a in which the driven element has been rotated to a centred / home / neutral position after the toggle has reached the drive position;

Figure 10a is a schematic representation of the castor control system of Figure 9a and in which the operating mode of the castor control system has been electrically changed from a drive mode to a brake mode by changing the toggle position from a drive position to a brake position;

Figure 10b is a schematic representation of the castor control system of Figure 10a in which the driven element has been rotated to a centred / home / neutral position after the toggle has reached the brake position;

Figure 11 is a schematic representation of the castor control system of Figure 3a in which the operating mode has been manually changed from a neutral mode to a brake mode;

Figure 12 is a schematic representation of the castor control system of Figure 3a in which the operating mode has been manually changed from a neutral mode to a drive mode;

Figure 13 is a schematic representation of the triple mode castor control system of Figure 3a in which the operating mode has been manually changed from a brake mode to a neutral mode;

Figure 14 is a schematic representation of the castor control system of Figure 3a in which the operating mode has been manually changed from a drive mode to a neutral mode;

Figure 15 is a schematic representation of the castor control system of Figure 3a in which the operating mode has been manually changed from a brake mode to a drive mode;

Figure 16 is a schematic representation of the castor control system of Figure 3a in which the operating mode has been manually changed from a drive mode to a brake mode;

Figure 17 shows another form of castor control system used to operate three castors;

Figure 18 shows another form of castor control system of the invention in which a transmission lever and toggle are integral, so as to form a single component; and

Figure 19 shows a stretcher, which is one form of wheeled apparatus, comprising one form of castor control system of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention is further described with reference to the following examples. It will be appreciated that the invention as claimed is not intended to be limited in any way by these examples.

As exemplified in Figures 1 to 17, the present invention relates to an electro-mechanical castor control system 1000 for a chassis 2000 of a wheeled apparatus 3000. A wheeled apparatus that may be used with the invention includes, for example, hospital beds, nursing care beds, gurneys, stretchers, patient lifts, surgical tables, diagnostic equipment, wheelchairs, trolleys, medical or hospital equipment or any other equipment supported by a chassis that is mounted on a plurality of castors that are moveable between different modes of operation by an electrically powered motor. The invention may be particularly suited for use with a patient transport apparatus, such as a hospital bed, nursing care bed, gurney, stretcher, cot, or transport chair.

The castor control system 1000 of the invention is adapted to be used with a chassis 2000 of a wheeled apparatus. The chassis 2000 comprises a chassis frame 2100 that is mounted on/supported by a plurality of controllable swivel-mounted castors 2200, such as two or more castors. In preferred forms, the castor control system 1000 may be used with a chassis 2000 comprising two castors, three castors, or four castors.

The castor control system 1000 may therefore be mounted to the chassis frame 2100 and adapted to operably engage with the castors.

The chassis frame 2100 may be any suitable frame of any suitable shape for mounting on the castors 2200 and providing support to the wheeled apparatus.

Typically, the castors 2200 include a swivel mount, a pair of rotatably supported wheels 2210 attached to the swivel mount to provide mobility to the chassis, and a brake to brake and release the wheels, and to simultaneously brake and release the castor swivel. The wheels 2210 are adapted to rotate and swivel relative to the chassis during movement of the wheeled apparatus.

In some forms, the wheeled apparatus may comprise a support frame that is attached to the chassis and that supports one or more elements above the chassis. For example, where the wheeled apparatus comprises a patient transport apparatus, such as a hospital bed, the apparatus may comprise a support frame 3100 that is attached to or integral with the chassis frame 2100. The support frame 3100 is located above the chassis frame and is adapted to support a patient on the apparatus. Where the wheeled apparatus comprises a bed or stretcher, the apparatus comprises a deck 3200 disposed on the support frame 3100. The deck 3200 provides a patient support surface on which a mattress may be located and on which a patient may be supported. The deck may be formed as a single part or as a plurality of articulated parts, as shown in relation to the stretcher exemplified in Figure 19. Patient barriers/side rails 3300 may be attached to the support frame and/or deck and may extend along at least a portion of the deck to help prevent a patient from falling from the deck. In some forms, a headboard and a footboard 3400 may be attached to the support frame and provided at head and foot ends of the deck respectively. At least one user interface 3550, comprising one or more elements for receiving user inputs, may be provided at the head end and or foot end to raise and lower the deck, or to select the operation mode of one or more castors 2200 attached to the chassis frame 2100, or both. In preferred forms, the user interfaces 3550 at the head and/or foot of the bed comprise handles 3500 to enable a user/operator to steer and manipulate the wheeled apparatus 3000. Additionally or alternatively, a user interface may be provided on at least one of the side rails to raise and lower the deck, or to allow a desired operating mode of the castors to be selected, or both.

Any suitable number of castors 2200 can be used to stably support the chassis frame 2100. In preferred forms, the frame 2100 may have a substantially square or rectangular area of coverage. For example, the frame itself may be substantially square or rectangular or it may be substantially I-shaped. In such forms, it may be preferable to use at least four castors 2200 to support the frame 2100 of the chassis - one castor being attached to the chassis and located at or near each corner of the frame 2100.

In other forms, the chassis may be supported by three castors, for example.

The castor control system 1000 of the invention allows the operating mode of the castors 2200 to be electrically controlled and manually controlled by allowing a user/operator to select a desired operating mode of the castors 2200. The castor control system 1000 provides at least two operating modes, and preferably three operating modes, that are each selectable by an operator via the user interface or manually. For example, where three operating modes are provided, an operator may select a desired steering mode (neutral mode or drive mode), by which to move the wheeled apparatus, or select a brake mode to prevent movement of the apparatus.

In preferred forms, the castors 2200 are adapted to operate in at least two different modes, such as a brake mode and a drive mode, or a brake mode and a neutral mode. Preferably the castors 2200 are adapted to operate in three different modes, such as a brake mode, a neutral mode, and a drive mode. The drive mode and neutral mode are both generally referred to herein as steering modes. In the drive mode, the castors are typically able to be steered in generally forward and backward directions. In the neutral mode, the castors are able to be steered in generally forward, backward, and sideways directions. In the brake mode, the castors are locked in position and prevented from moving forward, backward or sideways. Such controllable castors 2200 are readily available and are well known, such as those provided by Tente® at www.tente.com.

The castor control system 1000 also comprises an actuation system adapted to allow electrical selection of the castor operating modes by a user/operator.

The castors 2200 are adapted to change modes electrically by input from an actuation system 1100, comprising an electrically powered motor 1110 that is controlled by a controller 3000, according to user inputs entered through a user interface 3100 by an operator. In some forms, the controller 3000 is a programmable controller that comprises a processor and a memory device that enables the processor to store, retrieve, and/or execute instructions stored in the memory device. The controller 3000 is operably connected to the actuation system 1100 and is adapted to execute instructions in response to user inputs received via the user interface. The controller 3000 is also adapted to receive signals from one or more sensors, such as one or more position sensors, and to execute instructions to control and manipulate the actuating system according to the signals received. Each sensor may transmit a signal continuously, periodically, or only once, such as according to a signal request from the controller.

The actuation system 1100 is connected to the castors 2200 via a transmission system 1200, which is adapted to allow the operating mode of the castors 2200 to be changed as a result of user inputs, such as electrical inputs via the user interface, or manual inputs via operation of at least one pedal of the castor control system 1000.

Therefore, the actuation system 1100 and the transmission system 1200 of the castor control system 1000 of the invention operate together to allow the castors 2200 to be controlled electrically and manually. The castor control system 1000 may also be adapted to allow for a manual override of the motor 1110, such as when power is lost to the system 1000 or the motor 1110 fails and the castors 2200 are locked in the brake mode or any other mode of operation that needs to be changed. In some forms, the motor 1110 is back-driveable to reduce damage to the motor during a manual override operation.

As exemplified in Figures 1 to 2a, the transmission system 1200 comprises a linkage arrangement comprising a plurality of linked members: a transmission link 1210, at least one rotatable control element 1220, and at least one transmission lever 1230. The transmission link 1210 is operably connected to the at least one control element, such as via the at least one transmission lever 1230 that is rotatably attached to the transmission link via a pivot pin or pivot joint to rotatably connect a respective control element 1220 to the transmission link 1210.

The transmission link 1210 is capable of reciprocal back and forth movement, For example, the transmission link may be slidably moveable / translational in a first direction and a second direction. Preferably, the transmission link 1210 is substantially linearly moveable in the first and second directions. For example, the transmission link 1210 may comprise a first end 1210a projecting in the first direction and a second end 1210b projecting in the second direction and the link 1210 may be moveable back and forth between the first and second directions. Preferably, the transmission link 1210 is an elongate member such as an elongate bar or rod that is moveable back and forth along its length. In some forms, the transmission link 1210 extends along at least a portion of the length of the chassis 2000, such as along one side of the chassis. In some forms, the transmission link 1210 extends substantially along the length of the chassis in a front to rear direction. In other forms, the link 1210 extends substantially along the width of the chassis in a side-to-side direction.

At least one control element 1220 is rotatably connected to the transmission link 1210 by a transmission lever 1230. The control element 1220 comprises a major axis, such as its longitudinal axis, and is rotatable about that axis. In some forms, the at least one rotatable control element 1220 comprises an elongate member such as an elongate bar or rod. Typically, the at least one control element 1220 extends substantially perpendicular to the transmission link 1210 and to the transmission lever 1230. In some forms, the transmission link 1210 extends along at least a portion of the length of the chassis 2000, such as between front and rear ends of the chassis, and the at least one control element 1220 extends across the width of the chassis 2000, such as between left and right sides of the chassis. Optionally, the at least one control element 1220 is located near one end of the transmission link 1210. For example, where the transmission system 1200 comprises a single control element 1220, the control element may be located near a first end 1210a of the transmission link. The second end 1210b of the transmission link may be freely moveable in a linear direction or may be slidable along a guide mounted on the chassis frame 2100.

The at least one rotatable control element 1220 is operably engageable with at least one castor 2200 of the chassis 2000. Where a single castor is engageable with the control element 1220, the castor 2200 is attached to the chassis and is typically located substantially centrally along the length of the control element 1220. In other forms, a pair of castors 2200 are operably engageable with the control element 1220 and are attached to the chassis and located at or near opposing ends of the control element 1220, as shown in Figure 1.

In some forms, the castor control system 1000 comprises a single control element 1220 that is operably engaged with a single castor or a pair of castors, as described above. In such forms, the chassis may comprise at least one other wheel that is not a controlled castor. Preferably, the chassis comprises at least two other wheels. Where the system 1000 comprises a single control element 1220 that is operably engageable with a pair of castors, one of which is located at each end of the control element, the system 1000 controls the operating mode of both castors 2200 simultaneously. This arrangement may be suitable for relatively small, a wheeled apparatus, such as a trolley, or diagnostic equipment mounted on a small chassis, for example.

In some forms, as shown in Figure la, the transmission system 1200 comprises a pair of first and second rotatable control elements 1220a, 1220b (as described above) and a pair of first and second transmission levers 1230a, 1230b that rotatably connect the control elements to the transmission link 1210 via a respective pivot pin 10 or pivot joint that is mounted on the transmission link and is rotatably attached to the respective transmission lever. Each transmission lever is rotatably connected to the transmission link and fixedly connected to a control element to translate sliding movement of the transmission link to rotational movement of the control element and vice versa. The first control element 1220a may be located near a first end 1210a of the transmission link and the second control element 1220b may be located near a second end 1210b of the transmission link 1210. As above, the control elements 1220a, 1220b are each preferably perpendicular to the transmission levers 1230a, 1230b and the transmission link 1210.

The transmission system is adapted such that the transmission link(s) and control element(s) are operatively connected so that movement of any one of the transmission links or control elements will simultaneously cause movement of the other components of the transmission system (i.e. of the other transmission link and control element(s), as the case may be).

In preferred forms, the transmission system 1200 comprises one transmission link, two control elements 1220a, 1220b (as described above), and four castors 2200, with the castors being attached to the control elements 1220a, 1220b at or near each end of the control elements 1220a, 1220b. In these forms, the castor control system 1000 controls the operating mode of all four castors 2200 simultaneously. Such an arrangement is well-suited for a larger wheeled apparatus where maximum control of the castors 2200 is desirable, such as for use with hospital beds, nursing care beds, and stretchers, for example, as it allows greater control of a wheeled apparatus that can otherwise be unwieldly to maneuver.

Where the castor control system 1000 comprises two control elements 1220a, 1220b operably engageable with three castors, as shown in Figure 17, a castor 2200 may be located at each end of a first control element 1220a, and a castor may be located between the opposing ends of the second control element 1220b. In this form, the system 1000 controls the operating mode of all three castors 2200 substantially simultaneously.

Typically, the transmission system is adapted to transmit rotational output from the motor 1110 into rotation of at least one control element 1220a, 1220b that engages with one or more castors to change the operating mode of the castor(s) 2200.

Each castor 2200 comprises a castor drive mechanism that is adapted to brake the castor or to allow the castor to move, such as in the drive mode or the neutral mode, depending on the configuration of the castor control system. The engagement between a control element 1220 and the drive mechanism of the operably engaged castor are known in the art. For example, in some known forms of castors, each castor comprises a pintle and a cam, which is located at the top of the pintle. The cam comprises an internal opening, such as a hex-shaped opening, which snugly receives a portion of the control element 1220 therein, such as a control element comprising a hex-shaft (a shaft having a hexagonal lateral crosssection). As a result, when the control element 1220 rotates, the cam rotates with rotation of the control element 1220, and the mechanism inside the castor engages the castor in brake, neutral, or drive modes.

By engaging a control element 1220 with a drive mechanism of at least one castor, it is possible to cause the drive mechanism to change the operating mode of the castor by rotating the control element. The arrangement between the control element(s) and castor(s) will be described in further detail below. The transmission system 1200 comprises at least one transmission lever 1230 to transmit movement between the transmission link 1210 and at least one control element 1220. The transmission lever 1230 is rotatably connected to the transmission link 1210 and fixedly connected to the control element 1220, such that the transmission lever 1230 and the control element 1220 are unable to rotate relative to each other. Therefore, rotation of the transmission lever connected to the control element causes simultaneous rotation of the control element. In some forms, the transmission lever 1230 is rotatably connected to one end 1210a, 1210b of the transmission link 1210, but in other forms, the transmission lever 1230 may be rotatably connected at any suitable point along the length of the transmission link 1210. The transmission lever 1230 may be connected to the control element 1220 at any point between opposing ends of the control element and is typically arranged to extend substantially perpendicular to the control element 1220.

In some forms, to fixedly couple the transmission lever 1230 to a control element 1220, the control element 1220 is adapted to engage with the transmission lever 1230 to cause simultaneous rotation of the control element 1220 and the transmission lever 1230, and to prevent rotation of the control element 1220 relative to the transmission lever 1230 and vice versa. For example, the control element 1220 may comprise an engagement feature that engages with an engagement feature of the transmission lever 1230 to cause simultaneous rotation of the control element 1220 and the transmission lever 1230 and to prevent rotation of the control element 1220 and the transmission lever 1230 relative to each other. In some forms, as shown in Figure la, at least a portion of the control element 1220 may comprise a non-circular lateral cross-section and the corresponding engagement feature 1235 of the transmission lever 1230 may comprise a correspondingly shaped and similarly dimensioned opening for snugly receiving a portion of the control element 1220 therein. For example, a portion of the control element 1220 may comprise a square, hexagonal, octagonal, triangular, spline, or any other suitable noncircular lateral cross-section for engaging with a correspondingly shaped opening of the transmission lever 1230. However, it is envisaged that the engagement feature of the transmission link 1210 may be adapted to engage with the control element 1220 in any suitable manner that substantially prevents rotation of the control element 1220 and the transmission lever 1230 relative to each other, as will be appreciated by someone skilled in the art. For example, the transmission lever may comprise clamping arms that clamp against opposing surfaces of the control element, orthe transmission lever may be secured to the control element by one or more fasteners, such as by screwing or bolting the transmission lever to the control element. Alternatively, the transmission lever may comprise a projection for mating with an opening in the control element, or vice-versa, in order to non-rotationally connect the transmission lever and control element together. In yet other forms, the transmission lever and control element may be welded together or integrally formed as a single part.

In preferred forms, as shown in Figure la, the transmission system 1200 comprises two transmission levers 1230a, 1230b, as described above, that are each rotatably connected to the transmission link 1210 (or to each transmission link, where the system 1000 comprises two transmission links), and are each fixedly connected to a respective one of two control elements 1220a, 1220b. Preferably, one of the transmission levers 1230a, 1230b is rotatably connected to the transmission link at or near each distal end 1210a, 1210b of the transmission link 1210 and is fixedly connected to a respective control element 1220a, 1220b located near the respective end 1210a, 1210b of the transmission link 1210. In other forms, each transmission lever 1230a, 1230b may be rotatably connected to the transmission link at any point along the length of the transmission link 1210 (although it is preferable that the first transmission lever 1230a is connected to the transmission link 1210 between a central point of the transmission link and the first end 1210a of the link, and that the second transmission lever 1230b is connected to the transmission link 1210 between a central point of the transmission link and the second end 1210b of the link). Preferably, a togglell20 is rotatably connected to the transmission link 1210 at a location between the transmission levers 1230a, 1230b and is also rotatably connected to the chassis 2000 or support frame to slidably move the transmission link in opposing first and second directions upon rotation of the toggle.

The castor control system 1000 allows for each castor 2200 to be selectively moved between at least two, and preferably three, different operating modes by a user who may operate the system 1000 electrically or manually. To allow for manual operation of the castor control system 1000, the system 1000 comprises at least one manual actuator, such as a pedal 1240, associated with at least one of the castors 2200. The pedal is fixedly connected to the rotatable control element 1220 that operably engages with that castor 2200. Thus, the pedal is rotatable between positions corresponding to the different operating modes of the castors. In preferred forms, the castor control system 1000 comprises a plurality of pedals 1240 for manually controlling a plurality of castors 2200. Each pedal 1240 is moveable between a brake position and a steer position to cause the respective castor to operate in a brake mode or a steerable mode respectively (such as a neutral mode, or a drive mode). For example, the castor control system 1000 may comprise two control elements 1220a, 1220b for controlling three orfour castors 2200, and may also comprise three or four pedals 1240 respectively, the pedals being connected to the control elements 1220a, 1220b and each pedal 1240 being associated with a respective one of the castors 2200. For example, a chassis 2000 for a hospital bed, a nursing care bed, or a stretcher, may comprise four castors 2200 (one castor at or near each corner of the frame), and four pedals, each pedal 1240 being fixedly connected to a control element 1220, such that the pedal 1240 and respective control element 1220 are unable to rotate relative to each other, as shown in Figures 1 and la.

Regardless of the number of pedals 1240 present in the castor control system 1000, the configuration and operation of each pedal 1240 remains the same. Therefore, for simplicity, the configuration and operation of the pedals will be described mostly in relation to one pedal only.

Each pedal 1240 is rotatable between a brake position and at least one steer position (such as a drive position or a neutral position). Preferably, each pedal 1240 is rotatable between three positions: a brake position, a neutral position, and a drive position. For example, in different forms of the invention, the pedal 1240 may be moveable between a brake position and a neutral position; or between a brake position and a drive position; or between a brake position, a neutral position, and a drive position.

Each pedal 1240 of the castor control system 1000 is fixedly connected to a rotatable control element 1220 and is rotatable about the major axis of the control element 1220. Rotating the pedal 1240 allows the pedal to adopt a different position. Preferably, the pedal 1240 is connected to the respective control element 1220 at an end of the control element 1220. For example, one pedal 1240 may be connected to each end of a control element 1220, as shown in Figure la. As the control element 1220 rotates under powered/electrical operation, the connected pedal(s) 1240 is/are caused to rotate between different positions, such as the brake, neutral, and drive positions, and the castors are caused to change operating modes according to the pedal position. Similarly, by manually rotating the pedal 1240 from one position to another, the control element 1220 will rotate simultaneously and the castors will change operating mode.

Preferably, the castor control system 1000 comprises a pair of rotatable control elements 1220a, 1220b connected to the transmission link 1210 by transmission levers 1230a, 1230b, as described above, and each control element 1220a, 1220b is fixedly connected to a pair of pedals 1240 to cause simultaneous rotation of the control elements 1220a, 1220b and pedals 1240. Similarly, rotation of at least one of the pedals 1240 from one position to another, causes simultaneous rotation of both control elements 1220a, 1220b and all other pedals 1240. Each pedal is preferably located at or near opposing ends of the respective control element 1220a, 1220b.

Typically, each pedal 1240 comprises a substantially planar member 1241 that is rotatable about the major axis of the control element 1220 to which the pedal is attached. Preferably, the axis of rotation of each pedal is generally centrally located between opposing first and second ends of the pedal 1240. In some forms, the planar member 1241 of the pedal is substantially horizontal with the ground (when the chassis is on a flat surface) and/or with the frame 2100 of the chassis when the pedal 1240 is in the neutral position, as shown in Figure 2. Where the pedal is capable of adopting three different positions, the pedal 1240 may be rotated from neutral to adopt a drive position or brake position in which either the first or the second end of the planar member 1241 is raised. For example, the first end of the pedal 1240 may be raised in the drive position and lowered in the brake position as shown in Figures 3a and 5a respectively, or the second end of the pedal 1240 may be raised in the drive position and lowered in the brake position. Where the pedal 1240 is capable of adopting two different positions, the pedal is rotatable between the brake position and the drive position, or between the brake position and the neutral position.

The castor control system 1000 allows for simultaneous rotation of all pedals 1240 connected to the control element(s) 1220, which results in a simultaneous change in the operating mode of all castors 2200 that are operably engaged with the control element(s) 1220. For example, movement of one of the pedals 1240 from a brake position to a neutral or drive position will cause all the pedals 1240 to move to the same neutral or drive position, and will cause all castors 2200 engaged with the control element(s) 1220 to change from a brake mode to a neutral mode or drive mode, as the case may be.

The transmission system 1200 is electrically powered by the actuation system 1100, which preferably comprises at least a motor 1110 and a toggle 1120. In some forms, a transmission lever 1230 of the linkage arrangement may form the toggle, as will be described herein.

In some forms, the actuation system 1100 may also comprise a drive means to connect the motor 1110 to the toggle 1120, which is rotatably connected with the transmission system, such as with the transmission link, via a pivot 1126, to change the operating mode of the castors. In some forms, the drive means comprises a gear system 1130. The motor 1110 allows the toggle 1120 (and gears within an optional gear system 1130) to be rotated clockwise and anti-clockwise in order to adopt different positions and to thereby electrically change the operating mode of the castors 2200.

In some forms, the motor 1110, at least a portion of the toggle 1120, and at least a portion of the optional gear system 1130, may be located in a housing 1160. A second motor for independently powering an electric drive wheel attached to the chassis 2000 may also be located within the housing.

In some forms, the toggle 1120 comprises a first end 1120a that rotates about a pivot 1125, and a second end 1120b that is rotatably connected to the transmission system, such as to the transmission link 1210, at a second pivot 1126, and the toggle arm extends between the first and second ends 1120a, 1120b.

In some forms, as shown in Figures 2 to 2c, the rotating togglell20 comprises an arm 1121 extending from the first end 1120a of the toggle and terminating at the second end 1120b of the toggle. In some forms, the first end 1120a of the toggle forms a bulbous pivot end. In other forms, as shown in Figure 2d, the toggle 1120 may comprise a toggle arm 1121 and a first end 1120a that forms a non-bulbous extension of the toggle arm. However, it should be appreciated that the toggle may take any suitable form.

The first end/pivot end 1120a of the toggle rotates about a fixed axis at the first pivot 1125. The second end 1120b of the toggle is rotatably connected to the moveable transmission link 1210 at the second pivot 1126. Therefore, rotation of the toggle 1120 in a first direction causes the transmission link 1210 to move in the first direction and rotation of the toggle in a second, opposite direction causes the transmission link 1210 to move in the second, opposite direction.

In some forms, the first end of the toggle 1120 may be rotatably and operably directly connected to the motor 1110 via the drive means of the gear system 1130, such that rotation of the motor 1110 in a first direction causes clockwise rotation of the toggle 1120, and rotation of the motor 1110 in a second, reverse direction causes anti-clockwise rotation of the toggle 1120. In such arrangements, the actuation system does not include a driven element. However, in preferred forms, the actuation system comprises a driven element 1150 and the motor 1110 is directly or indirectly connected to the driven element 1150 and that the driven element is adapted to rotate the toggle 1120 in the direction of rotational movement of the driven element as a result of the output of the motor 1110.

In the example shown in Figures 2 and 2a, the toggle 1120 comprises an arm 1121 and a bulbous pivot end/ first end 1120a, located at one end of the arm 1121, that rotates about a fixed axis at the first pivot 1125. The first end 1120a of the toggle may be rotatably and operably connected to the motor 1110 via a gear system 1130. The toggle also comprises a second end 1120b, located at the opposing end of the arm 1121, that rotatably connects with the moveable transmission link 1210 at the second pivot 1126. In preferred forms, the toggle 1120 is rotatably connected to the transmission link 1210 at a substantially central region along the length of the transmission link 1210 and optionally slightly off-centre. However, it should be appreciated that the toggle 1120 may be connected to the transmission link 1210 at any point along the length of the link 1210. It should also be appreciated that in some forms, the toggle consists of a transmission lever 1230 of the transmission system. For example, as shown in Figure 18, one of the transmission levers 1230 connecting the transmission link 1210 to a control element 1220 may consist of a toggle 1120 such that the transmission lever 1230 and toggle 1120 are integral as a single component. The toggle is rotatable between at least two positions, as disclosed herein, and as the toggle rotates in a first direction to move between positions, the toggle/transmission lever 1120/1230 moves the transmission link 1210 in the first direction, which rotates the attached control element 1220 in a first direction, which changes the operating mode of the castor(s) 2200 with which the control element 1220 is engaged. Similarly, rotating the toggle/transmission lever 1120/1230 in a second direction, moves the transmission link 1210 in the second direction, to rotate the attached control element 1220 in a second direction to change the operating mode of the castor(s) 2200.

By rotating the toggle 1120 about its first end/pivot end 1120a, it is possible to move the toggle 1120 between different positions in which the second, distal end 1120b of the toggle follows a generally arcuate path from one position to another. A virtual radial line may be drawn between the second end 1120b of the toggle and its axis of rotation at pivot 1125 when the toggle 1120 is at a first position and again when the toggle reaches a second position. The angle created by the second end 1120b of the toggle between the virtual radial lines in the first and second positions may be any suitable angle, but is preferably between 0° and 90° and is more preferably between 0° and 30°. In some forms, the maximum angle of rotation of the toggle between two positions is about 60°.

The positions of the toggle 1120 may correspond with the different operating modes of the castors 2200. For example, if the castors 2200 are adapted to operate in two different modes: a brake mode and a drive mode, or a brake mode and a neutral mode, then the toggle 1120 is adapted to adopt two different corresponding positions: a brake position and a drive position, or a brake position and a neutral position, as the case may be, and as indicated in Figures 7 to 10b. Similarly, if the castors 2200 operate in three different modes: a brake mode, a neutral mode, and a drive mode, then the toggle 1120 is adapted to adopt three different corresponding positions: a brake position, a neutral position, and a drive position. In this way, by moving the toggle to the brake position, the castors are caused to change to the brake mode. Similarly, by moving the toggle to the neutral position or the drive position, the castors are caused to change to the neutral mode or the drive mode respectively. Preferably, the toggle is substantially perpendicular to the transmission link 1210 in the neutral position.

Preferably, the actuation system comprises a drive means that engages with the motor and is adapted to rotate the toggle between positions under power from the motor 1110. However, the motor and drive means may also be adapted to allow the toggle 1120 to rotate between positions, under manual operation of the castor control system 1000.

In some forms, as shown in Figures 2 and 2a, the drive means comprises a gear system 1130 comprising a rotatable drive gear 1140 and a rotatable driven gear/ driven element 1150 that is supported by the chassis and is rotatable by the motor in a first direction and in a second direction. The drive gear 1140 is adapted to engage with the driven element 1150 and to be driven in a clockwise direction or an anti-clockwise direction by the motor 1110. Rotation of the drive gear 1140 drives rotation of a driven element 1150 in a clockwise direction or an anti-clockwise direction. The drive gear 1140 and driven element 1150 are adapted to rotate in opposite directions.

In other forms, the drive means comprises only a driven element 1150 and the motor output is directly connected to the driven element.

The motor 1110 and driven element 1150 are adapted to cause the toggle 1120 to rotate between different positions, corresponding to the different operating modes of the castors, to effect a change in the operating mode of the castors 2200.

In some forms, the driven element 1150 may comprise a substantially arcuate periphery having a circumferential surface, at least a portion of which comprises a plurality of teeth 1153 adapted to mesh with teeth 1142 of the drive gear 1140 in order to engage the drive gear 1140 with the driven element 1150. In this arrangement, rotation of the drive gear 1140 by the motor 1110 causes rotation of the driven element 1150 to move the driven element between different positions. However, it should be appreciated that the driven element and drive gear may be adapted to engage with each other in any suitable manner, such as those known in relation to gear systems, as would be appreciated by a person skilled in the art.

The driven element 1150 comprises a body comprising an opening at least partially defined by a pair of contact surfaces. Preferably, the contact surfaces are substantially opposing contact surfaces. The toggle 1120 is at least partially located within the opening and between the contact surfaces, such that rotation of the driven element relative to the toggle, to the extent that the driven element and toggle contact each other, will cause one of the contact surfaces of the driven element to contact an adjacent side of the toggle to urge the toggle in the same direction as the driven element.

In some forms, the driven element may comprise a substantially circular body comprising an opening therein, such as an opening forming a sector of the circular body. However, it should be appreciated thatthe driven element may be of any suitable shape comprising an opening in which at least a portion of the toggle may be located. The shape of the driven element may be a substantially regular shape such as a hexagonal shape, a square shape, or an octagonal shape for example. Or, the shape of the driven element may be a substantially irregular shape such as a tear drop or ovoid shape for example.

The first end 1120a of the toggle is rotatably connected to the motor 1110 via the gear system 1130. The toggle rotates about an axis of the first pivot 1125 at its first end 1120a. The driven element 1150 is independently rotatable relative to the toggle 1120 about an axis, which is preferably, but not essentially, the same axis as the first pivot 1125 of the toggle.

In some forms, as shown in Figures 2 to 2d, the driven element 1150 comprises a substantially C- shaped body comprising an opening at least partially defined by a pair of substantially opposing contact surfaces located on inner surfaces of a pair of splayed arms 1152a, 1152b, such that the opening 1151 is located between the splayed arms 1152a, 1152b. The toggle 1120 is at least partially located within the opening 1151. Each arm 1152a, 1152b is adapted to press against and urge the toggle from one position to another. For example, each arm 1152a, 1152b of the driven element 1150 comprises a contact surface 1150a, 1150b, that faces toward the toggle 1120 and is adapted to contact the toggle to urge the toggle to rotate from one position to another as the driven element 1150 rotates relative to the toggle to the extent that the driven element contacts the toggle.

Optionally, at least a portion of each contact surface 1150a, 1150b lies along a respective virtual radial line extending from the axis of rotation of the driven element 1150. The angle formed between the axis of rotation of the driven element 1150 and each of the contact surfaces, which (by triangulation) defines the distance between the contact surfaces of the arms 1152a, 1152b, is adapted to be at least equivalent to, and preferably greater than, the maximum angle of rotation of the toggle 1120 when rotating between positions. Preferably, the angle formed is less than 90°, such as about 60°, or about 30°. In some forms, the toggle 1120 rotates about 30° from one position to another and the driven element is adapted so that the angle formed by each contact surface and the axis of rotation of the driven element is at least 30°. For example, where the toggle 1120 rotates 30° between just two positions, such as between the brake and neutral positions or between the brake and drive positions, the angle formed between the axis of rotation of the driven element 1150 and its contact surfaces is at least 30° and is preferably at least 40°. Where the toggle 1120 rotates about 30° between each of three positions, such that the maximum angle of rotation of the toggle 1120 (between the outermost positions) is about 60°, then the driven element is adapted so that the angle formed between the axis of rotation of the driven element 1150 and its contact surfaces is at least about 60° and is preferably at least about 70°.

By rotating the drive gear 1140, the driven element 1150 is also caused to rotate so that one of the contact surfaces 1150a, 1150b of the driven element 1150 is caused to contact a proximate side of the toggle 1120 (such as the closest side of the toggle arm 1121) and urge the toggle 1120 to rotate from one position to another. For example, where the driven element 1150 is rotated clockwise, the contact surface 1150a of the driven element arm 1152a to the left of the toggle 1120 may be caused to press against the left side of the toggle 1120 to rotate the toggle clockwise. Similarly, where the driven element 1150 is rotated anti-clockwise, the contact surface 1150b of the driven element arm 1152b to the right of the toggle 1120 may be caused to press against the right side of the toggle 1120 to rotate the toggle anticlockwise.

The configuration of the driven element and toggle may take any suitable form that locates the toggle within an opening formed between contact surfaces of the driven element and that provides a space between the toggle and each contact surface of the driven element when the toggle is centrally positioned between the contact surfaces of the driven element. The space/gap between the toggle and each contact surface allows the toggle and/or the driven element to rotate, to some extent, without contacting the other of the driven element or toggle.

Preferably, the driven element 1150 comprises a body comprising a pair of arms 1152a, 1152b extending from the body, and a central opening 1151 located between the arms 1152a, 1152b and within which at least a portion of the toggle 1120 may be located. The arms 1152a, 1152b each comprise a contact surface that is adapted to contact and push against an adjacent contact surface of the toggle 1120, such as a surface of the toggle that faces toward the respective contact surface of the driven element arm 1152a, 1152b. Preferably, the body forms a base portion of the driven element 1150 and the arms 1152a, 1152b extend from the base portion and splay outwardly to some extent.

In some forms, as shown in the embodiment of Figures 2, 2a, and 2b, each of the splayed arms 1152a, 1152b comprises a contact surface 1150a, 1150b at a distal end of the arm to press against an adjacent side surface of the toggle 1120. For example, as shown best in Figures 2a and 2b, the driven element 1150 may comprise a substantially C-shaped body comprising a central opening 1151 within which the first end 1120a of the toggle 1120 is located. Preferably, the opening 1151 is substantially circular, and the first end 1120a of the toggle is also substantially circular or bulbous and is rotatably located within the opening 1151. Preferably, both the first end 1120a of the toggle and the driven element 1150 are independently rotatable about a single, shared, fixed axis at the first pivot 1125. Preferably, the axis of rotation (at the first pivot 1125) of the toggle and the driven element is substantially centrally located within the first end 1120a of the toggle 1120 and the opening 1151 of the driven element 1150 respectively, as shown in Figure 2a.

The substantially C-shaped body of the driven element 1150 comprises a pair of arcuate, splayed arms 1152a, 1152b that terminate at a first end and a second end. Each end of the driven element arms faces inwardly toward the other and comprises a contact surface that faces towards the toggle 1120, located between the arms 1152a, 1152b. Each contact surface 1150a, 1150b is adapted to press against an adjacent side of the toggle 1120 to rotate the toggle from one position to another when the driven element 1150 is rotated by the drive gear 1140. For example, each contact surface 1150a, 1150b may be adapted to press against a contact surface / region on each side of the toggle arm 1121 to rotate the toggle between positions. In preferred forms, the toggle contact surfaces are provided on opposing side regions of the toggle arm 1121. By rotating the driven element 1150, one of the contact surfaces 1150a, 1150b atthe terminal ends of the arms 1150a, 1150b of the driven element 1150 may therefore be caused to contact the toggle 1120 and urge the toggle 1120 to rotate from one position to another.

In other forms, as shown in Figure 2c, the driven element 1150 may be substantially U-shaped and may comprise a body comprising a base portion from which two upwardly extending arms 1152a, 1152b project. Preferably, the arms splay slightly outwardly. Each arm 1152a, 1152b comprises an inwardly facing surface that faces towards the toggle 1120 located between the arms. Each arm also comprises a distal end. A contact surface may extend from the distal end of each arm 1152a, 1152b and into the inner surface of each arm 1152a, 1152b to form a sloping contact surface 1150a, 1150b for pressing against the toggle 1120 to rotate the toggle from one position to another.

In yet another form, as shown in Figure 2d, the driven element 1150 may be substantially V- shaped and may comprise a body comprising a base portion from which two upwardly and outwardly extending splayed arms 1152a, 1152b project. An inner surface of each splayed arm 1152a, 1152b may form a contact surface 1150a, 1150b and may be adapted to press against an adjacent side surface/contact surface of the toggle 1120 to rotate the toggle from one position to another. Figure 2d also shows an alternative form of toggle 1120 comprising a substantially linear elongate member in which the first end 1120a of the toggle is substantially flush with the toggle arm 1121. Preferably, a virtual line bisects the driven element 1150 through its centre of rotation and each side of the driven element 1150 (on either side of the virtual line) is a mirror image of the other side. The first end/pivot end of the toggle 1120 and at least a portion of the toggle arm 1121 is located between the extending arms 1152a, 1152b of the driven element and the toggle arm 1121 is preferably substantially parallel with the virtual line when the toggle is positioned to be substantially equidistant from and spaced from each arm 1152a, 1152b.

In another form (not shown), the driven element may comprise a pair of arms that extend from the axis of rotation of the driven element. An opening is defined between the arms and in which at least a portion of the toggle is rotatably located. Each of the arms comprise a contact surface that faces inwardly towards the toggle. Each contact surface lies substantially along a virtual radial line extending from the axis of rotation of the driven element and is adapted to press against a contact surface / side region of the toggle to urge the toggle to move from one position to another when the driven element rotates. As described above, the toggle is rotatable between at least two positions, and the angle formed between the axis of rotation of the driven element and the virtual radial lines of the contact surfaces is at least equivalent to, and preferably greater than, the maximum angle of rotation of the toggle as the toggle moves between positions. For example, if the maximum angle of rotation of the toggle is 60° then the angle formed between the arms of the driven element is at least 60° and preferably at least 70°.

In yet another form (not shown), the driven element may be rotatable about an axis by operation of the motor and may comprise an arcuate slot sharing the same centre of rotation as the drive element. Terminal ends of the slot form contact surfaces of the driven element. The rotatable toggle may comprise a pin that is slidably received within the slot, such that rotation of the driven element in a first direction causes one of the contact surfaces to press against the pin and rotate the pin in the same direction until the pin reaches the desired position. The motor may then be reversed to rotate the driven element in the reverse direction to return to a home / neutral position.

In yet another form (not shown), the driven element may comprise a rotating plate and the toggle may be mounted on top of a first surface of the plate and may share the same axis of rotation as the driven element. A pair of spaced contact surfaces are provided on the plate to abut the contact surfaces at the side regions of the toggle arm to rotate the toggle in the clockwise and anti-clockwise directions.. For example, the plate may comprise an opening and the contact surfaces may be provided at substantially opposing side walls of the opening. Alternatively, the plate may comprise a pair of arms that are spaced apart and project from the first surface of the plate and may comprise contact surfaces. In each form, the toggle may be located within the opening and between the contact surfaces of the driven element plate.

In another form, the motor and driven element may be located so that the driven element shares the same rotational axis as a first control element. The motor may be directly coupled to the driven element, or the motor may be coupled to a drive gear that engages the driven element as part of a gear system, as described above. The first control element passes through the driven element, substantially central to the driven element, but is not directly coupled to the driven element or to the motor. The transmission lever is fixedly coupled to the control element, as described above, and acts as a toggle (it is not necessary to attach a separate toggle to the transmission link in this arrangement). The driven element may be a substantially C-shaped, U-shaped, or V-shaped driven element, as described above, or may be of any suitable shape in which the rotational axis of the first control element is located substantially centrally between opposing contact surfaces of the driven element, such that the transmission lever is rotatable between the contact surfaces of the driven element, as described above. In some forms, the maximum angle of rotation of the transmission lever / toggle between two positions is about 90°, but is preferably about 60°. In this form, and in the embodiment shown in Figure 18, to electrically change the operating mode of the castors 2200, the driven element 1150 is caused to rotate in a first direction (which may be clockwise or anti-clockwise) by the motor, which causes an contact surface of the driven element to contact a side region of a first transmission lever / toggle to cause the first transmission lever to rotate in the same direction. As the first transmission lever / toggle rotates, the attached first control element 1220 rotates in the same direction and the transmission link 1210 is moved in a first direction. Where the system includes two control elements, the transmission link moves the second transmission lever in the first direction, causing the second transmission lever to rotate in the same direction as the first transmission lever and simultaneously rotating the second control element. Rotation of the control elements causes a change in the operating mode of the castors.

In some forms, where the castors 2200 are adapted to operate in only two modes, then the toggle 1120 may be adapted to rotate between two positions and the driven element 1150 may be adapted to rotate between two positions, such as between a brake position and a drive position, or between a brake position and a neutral position. Alternatively, where the castors 2200 are adapted to operate in only two modes, the toggle 1120 may be adapted to rotate between two positions and the driven element 1150 may be adapted to rotate between three positions, such as a brake position; a centred, home / neutral position; and a drive position, as shown in Figures 7 to 10b and as will be described in further detail in relation to the use of the castor control system.

In some forms, where the castors 2200 are adapted to operate in three modes, both the toggle 1120 and the driven element 1150 are adapted to be moveable between three positions: a brake position, a neutral position, and a drive position. In some forms, the neutral position is considered to be a home position and is located substantially centrally between the brake and drive positions. The position of the toggle 1120 may determine the operating mode of the castors 2200. However, the position of the driven element 1150 may not necessarily determine the operating mode of the castors.

In preferred forms, the castors are adapted to operate in three different modes (brake, neutral, and drive) and the toggle is therefore adapted to move between three different positions (brake, neutral, and drive). In some such forms, when in the neutral position, the toggle arm 1121 is substantially centrally located between the contact surfaces 1150a, 1150b of the driven element, such as between the terminal ends of a substantially C-shaped driven element 1150, as described above. Preferably, when the driven element 1150 and the toggle 1120 are both located in the neutral position, the contact surfaces of the driven element are spaced equidistant from each adjacent side of the toggle arm 1121. The spacing is such that under manual operation of the castor control system 1000, it is possible for the toggle 1120 to be rotated between all three of its three possible positions, while the gear system 1130 (i.e., the drive gear and the driven element) remains static in a centred / home / neutral position, therefore avoiding the need to back-drive the motor 1110.

In some forms, under electric operation of the castor control system 1000, operation of the drive gear 1140 causes the driven element 1150 to rotate, clockwise or anti-clockwise, relative to the toggle 1120 to such an extent that a portion of the driven element presses against an adjacent portion of the toggle arm 1121, causing the toggle to rotate from one position to another. After moving the toggle 1120 to the desired position, the controller 3000 reverses the direction of the motor 1110 to return the driven element 1150 to the centred / home /neutral position in which the contact surfaces of the driven element are spaced equidistant from the sides of the toggle arm 1121. This arrangement means that, under manual operation of the castor control system 1000, the toggle 1120 may be caused to rotate from one position to another without pressing against the contact surfaces 1150a, 1150b of the driven element, thereby allowing the gear system 1130 and the motor 1110 to remain static.

Powered operation of the castor control system 1000 is controlled by the controller 3000 that connects to the motor 1110 and the user interface 3100. The user interface 3100 may be located at any suitable location on the wheeled apparatus. In preferred forms, as shown in Figure 1, the user interface may be located near handles for maneuvering the wheeled apparatus, which is particularly advantageous when the wheeled apparatus is a hospital bed or stretcher.

To operate the castor control system electrically, a user selects the desired operating mode of the castors 2200 from two or more available modes, via user inputs provided on the user interface 3100. The input selection is transmitted to the controller 3000, which actuates the motor 1110 to move the toggle 1120 (preferably through a gear system 1130) to a position corresponding to the selected operating mode. For example, if the user selects the brake mode via the user interface, the motor 1110 causes the toggle 1120 to rotate to the brake position. The castor control system may comprise one or more sensors, as shown in Figure 2b, that signal to the controller 3000 when the toggle has reached the desired position, at which time the controller 3000 stops the motor or reverses the motor to return the driven element to a centred neutral/home position in which the arm of the toggle is substantially centrally located between the contact surfaces of the driven element and is also spaced from the contact surfaces of the driven element to allow the toggle position to be manually changed without contacting the driven element.

Under powered operation, each pedal 1240 is also caused to rotate to a position (such as the brake position) corresponding to the selected operating mode (such as the brake mode) as the motor 1110 causes the toggle 1120 to rotate to a corresponding position (such as the brake position).

When the castor control system is under manual operation, each pedal 1240 is manually rotated to the desired position by a user. The castor control system 1000 is adapted so that each pedal position corresponds to a different mode of operation of the castors 2200. Manual rotation of a pedal 1240 causes simultaneous rotation of the control element 1220 to which the pedal is fixedly connected, which causes movement of the transmission link 1210 in the first or second direction (therefore causing corresponding rotation of the other control element 1220 and pedals 1240, where present). Movement of the transmission link 1210 causes rotation of the toggle 1120 to adopt a position corresponding to the position of the pedals 1240 and therefore the desired operating mode of the castors 2200. Because the castors 2200 are operably engaged with the control element(s) 1220, rotation of the control element(s) under operation of the pedals 1240 causes the castors to change operating mode. Therefore, when a pedal 1240 is manually rotated to the brake position, all other pedals 1240 are simultaneously rotated to the brake position, the toggle 1120 is rotated to the brake position and the castors 2200 are changed to operate in brake mode. When a pedal 1240 is rotated to the neutral position, all other pedals 1240 are simultaneously rotated to the neutral position, the toggle 1120 is rotated to the neutral position and the castors 2200 are changed to operate in neutral mode. Similarly, when the pedal 1240 is rotated to the drive position, all other pedals 1240 are simultaneously rotated to the drive position, the toggle 1120 is rotated to the drive position and the castors 2200 are changed to operate in drive mode. Therefore, the pedals 1240 are adapted to allow manual control of the operating mode of the castors 2200 by changing the position of just one of the pedals 1240.

In some forms, the castor control system 1000 is adapted to override the motor 1110 by moving at least one pedal 1240 from a first position to a second position to change the operating mode of the castors 2200 from a first mode to a second mode. For example, in some forms, each pedal 1240 provides a manual override of the electric motor when the castors are locked in brake mode, such that changing the position of at least one of the pedals from the brake position to the neutral position or to the drive position simultaneously changes the position of all of the pedals 1240 and the operating mode of the castors 2200. The operation of this feature is further explained below. Different ways in which the castor control system of the invention may be operated will now be described. The castor control system 1000 allows the operating mode of controlled castors 2200, of a wheeled apparatus with which the system is used, to be changed between a brake mode and a steer mode manually and electrically. The steer mode refers to one or more modes of operation in which the castors are steerable / moveable. For example, the steer mode may include a neutral mode of operation and/or a drive mode of operation. The castor control system 1000 may therefore be adapted to allow the castors 2200 to move between a brake mode and a neutral mode, or between a brake mode and a drive mode, or between a brake mode, a neutral mode, and a drive mode. Where the brake mode and only one steer mode is available, the pedals 1240 may be rotatable between only two positions. Similarly, the toggle 1120 may be rotatable between only two positions. The driven element 1150 may also be rotatable between only two positions, but is preferably rotatable between three positions and preferably employs a gear system to control output from the motor to the driven element.

Electric operation of one form of castor control system of the invention will be described in relation to the examples shown in Figures 1 to 6b, which illustrate a castor control system adapted to operate the castors in three different modes: a brake mode, a neutral mode, and a drive mode.

Referring first to Figures 1 and la, the castor control system exemplified is mounted on a substantially rectangular chassis 2000 for a hospital bed. The transmission link 1210 extends partially along the length from the chassis in a direction from front to rear, such that the first end of the link 1210 is near the head of the bed and the second end of the link 1210 is near the foot of the bed. The transmission link 1210 comprises an elongate member, such as a bar.

First ends of each of a pair of first and second transmission levers 1230a, 1230b are rotatably connected to first and second ends 1210a, 1210b of the transmission link 1210 respectively. In the neutral position, each transmission lever 1230a, 1230b is substantially perpendicular to the transmission link 1210.

Each transmission lever 1230a, 1230b is fixedly connected to a respective one of two rotatable control elements 1220a, 1220b of the transmission system 1200. Each control element 1220a, 1220b extends transversely across the chassis 2000, substantially perpendicular to the transmission link 1210. Each of the control elements 1220a, 1220b comprises a rod, having a hexagonal lateral cross-section (forming a hex-shaft), that is snugly received within a hexagonal opening of the respective transmission lever 1230 to which the control element 1220a, 1220b is connected. Each control element 1220a, 1220b is rotatable about its major axis, but is unable to rotate relative to the connected transmission lever 1230.

Each control element 1220a, 1220b extends between and is operably engaged with at least one castor, and preferably two opposing castors 2200 attached to the chassis frame and connected near the ends of the control element 1220. The control elements 1220a, 1220b and castors 2200 are adapted so that rotation of the control elements causes the castors to change a mode of operation between a brake mode and a steer mode, such as a drive mode or a neutral mode.

Each control element 1220a, 1220b is also fixedly connected to a pair of pedals 1240, each of the four pedals being located at opposing ends of the control element 1220 and proximate to one of the castors 2200. In the example shown in Figures 1 and la, each pedal 1240 is rotatable between the brake, neutral, and drive positions as the respective control element 1220 rotates.

The actuation system 1100 comprises an electrically powered motor 1110 that is controlled by a controller 3000, which may be a programmable controller, and that operates a rotatable drive gear 1140 that engages with a substantially C-shaped rotatable driven element 1150, as described above and shown in Figures 2, 2a, and 2b for example. The actuation system 1100 also comprises a rotatable toggle 1120 that, from a first end, rotates about a fixed axis 1125 that may be shared with the driven element 1150. A second end of the toggle 1120 is rotatably connected to the transmission link 1210. The toggle 1120 and driven element 1150 are capable of rotating independently. The driven element 1150 is, however, adapted, to press against the toggle arm 1121 during electric operation to cause the toggle to rotate to a desired position corresponding to the castor operating mode selected by a user, via electrical inputs from the electronic user interface 3100 that is operably connected to the controller 3000.

The castor control system depicted is adapted to cause the toggle to rotate between three different positions: a first position, a second position and a third position. For the purposes of demonstration, the first position designates a neutral position in which the castors are in neutral mode, the second position designates a brake position in which the castors are in brake mode, and the third position designates a drive position in which the castors are in drive mode. However, it should be appreciated that these positions are examples only and that the castor control system may be configured in any suitable way. For example, the first position may be the brake position, the second position may be the drive position, and the third position may be the neutral position.

In the arrangement shown in Figure 2, the toggle 1120 is in a first, neutral position in which the toggle arm 1121 is substantially perpendicular to the transmission link 1210. The driven element 1150 of the castor control system is also adapted to rotate between three different positions: a first centred / home / neutral position; a second / brake position; and a third / drive position. When the driven element is moved to the brake position, the toggle is moved to the brake position. When the driven element is moved to the drive position, the toggle is moved to the drive position. However, in some situations, when the driven element is moved to the centred / home / neutral position, the toggle may remain in the brake or drive position, as will be described in further detail.

As shown in Figure 3a, to electrically change the castors from the first / neutral mode to a second mode, such as a brake mode, the controller 3000, on receiving a brake mode input via the user interface, causes the motor 1110 to drive the drive gear 1140 in a first direction, such as an anti-clockwise direction. The drive gear engages with and drives the driven element 1150 in a second direction, such as a clockwise direction. The driven element 1150 is rotated to an extent that an contact surface at the terminal end of the driven element 1150 presses against an adjacent contact surface / side region of the toggle arm 1121 and pushes the toggle arm 1121 in the same direction as the driven element 1150 to rotate the toggle until the toggle reaches the second position / brake position. The second / brake position may be set at any desired angle from neutral. For example, the second / brake position of the toggle 1121 may be between about 20° and about 45° from neutral, and is preferably about 30° from neutral.

One or more position sensors are provided by the castor control system 1000 and may be mounted on the toggle, the transmission link, the drive element, the chassis frame, or on any other suitable component of the castor control system or wheeled apparatus. The position sensor(s) signal(s) to the controller 3000 that the toggle (or the driven element) has reached the desired position at which point the controller stops the motor or reverses the motor to return the driven element to the centred, neutral position.

As the toggle 1120 rotates in a first direction toward the second position, the transmission link 1210 is caused to move / translate in a first direction. Because the axes of the control elements 1220a, 1220b are fixed relative to the chassis, but the control elements 1220a, 1220b are each capable of rotation about their axes, the transmission levers 1230a, 1230b are caused to rotate in the first direction as the transmission link 1210 moves in the first direction.

Rotation of the transmission levers 1230a, 1230b causes simultaneous rotation of the control elements 1220a, 1220b to which the transmission levers are fixedly connected. The rotating control elements 1220a, 1220b engage with the castor control mechanism of each castor 2200 to change the operating mode of the castors 2200 to the second / brake mode. As the control elements 1220a, 1220b rotate, the pedals 1240 may also be caused to rotate simultaneously to adopt the second / brake position.

In preferred forms, as shown in Figure 3b, once the toggle 1120 reaches the second / brake position, the controller 3000 automatically reverses the operation of the motor 1110 to rotate the drive gear 1140 in the opposite direction, such as clockwise. The drive gear 1140 rotates the driven element 1150 in an opposite direction, such as anti-clockwise, until the driven element 1150 returns to a home position, which may be a substantially centred, neutral position. One or more sensors signal to the controller 3000 that the driven element has reached the desired neutral position and the controller stops the motor. The driven element 1150 is adapted so that when the driven element returns to its home / neutral position, neither of the contact surfaces of the driven element 1150 press against the toggle arm 1121 to move the toggle from its current second / brake position. By returning the driven element 1150 to a home / neutral position, the castor control system of the invention allows a faster response time for the driven element 1150 to rotate the toggle 1120 from its current brake position and back to the neutral position or to the drive position if a user selects a different operating mode.

To electrically change the castors 2200 from the second / brake mode to the first / neutral mode, as shown in Figures 4a and 4b, the controller 3000 causes the motor 1110 to operate the drive gear 1140 in a second direction, such as a clockwise direction. The drive gear engages with and drives the driven element 1150 in the first direction, such as an anti-clockwise direction. The driven element 1150 is rotated to an extent that an contact surface of the driven element presses against an adjacent contact surface / side region of the toggle arm 1121 and pushes against the toggle to rotate the toggle in the same direction as the driven element 1150 to rotate the toggle until the toggle reaches the first / neutral position. One or more position sensors signal to the controller 3000 that the toggle (or the driven element) has reached the desired position and the controller stops the motor or reverses the motor to cause the driven element to reach its centred, neutral position. As the toggle 1120 rotates in one direction and causes the transmission link to move in the same direction, the transmission levers 1130a, 1130b and control elements 1220a, 1220b are caused to simultaneously rotate such that the castors 2200 adopt the neutral operating mode and the pedals 1240 adopt the corresponding first / neutral position. In the example shown, the toggle arm 1121 and transmission levers 1130a, 1130b are substantially perpendicular to the transmission link 1210 (and preferably with the floor) and the pedals 1240 are substantially parallel with the transmission link when in the first / neutral position, but this is not essential.

After the toggle 1120 reaches the first / neutral position, the controller 3000 may cause the motor 1110 to automatically reverse direction to rotate the drive gear 1140 and the driven element 1150 in the reverse directions until the driven element 1150 returns to the centred / home / neutral position, as shown in Figure 4b. One or more position sensors signal to the controller 30000 that the driven element has reached the desired neutral position and the controller stops the motor.

Figures 5a and 5b illustrate how one form of castor control system 1000 can be electrically operated to change the castors 2200 from the neutral mode to the drive mode. For example, after receiving a drive mode input via the user interface, the controller 3000 actuates the motor 1110 to drive the drive gear 1140 in a second direction, such as a clockwise direction. The drive gear engages with and drives the driven element 1150 in a first direction, such as an anti-clockwise direction. The driven element 1150 is rotated to an extent that an contact surface of the driven element 1150 presses against an adjacent contact surface / side region of the toggle arm 1121 and pushes against the toggle arm to rotate the toggle 1120 in the same direction as the driven element 1150 until the toggle reaches the third / drive position. One or more position sensors signal to the controller 3000 that the toggle (or the driven element) has reached the desired drive position and the controller stops the motor or reverses the motor to return the driven element to the neutral position. The third / drive position of the toggle 1120 may be set at any desired angle from neutral. For example, the third / drive position of the toggle may be between about - 20° and about -45° from neutral, and is preferably about -30° from neutral. In some forms, the second / brake position and the third / drive position may be reversed, as would be readily appreciated by a person skilled in the art.

Rotation of the toggle 1120 in one direction to the third / drive position (such that the toggle is rotated in a direction opposite to the brake position), causes the transmission link 1210 to move in the same direction as the toggle (the second direction, as illustrated in Figure 5a). Movement of the transmission link 1210 causes rotation of the transmission levers 1130a, 1130b in the same direction and therefore simultaneous rotation of the control elements 1220a, 1220b to cause the castors 2200 to adopt the drive mode. As the control elements 1220a, 1220b rotate, the pedals 1240 are also caused to rotate to adopt the drive position. One or more position sensors signal to the controller 3000 that the toggle or driven element has reached the desired position, such as the drive position, and the controller 3000 stops the motor or may cause the motor 1110 to automatically reverse direction to rotate the drive gear 1140 and the driven element 1150 in the reverse directions until the driven element 1150 returns to the centred / home / neutral position, as shown in Figure 5b. One or more position sensors signal to the controller 3000 when the driven element has reached the desired neutral position and the controller stops the motor.

As shown in Figure 6a and 6b, to electrically change the castors 2200 from the drive mode to the neutral mode, the controller 3000, on receiving a 'neutral mode' user input via the user interface 3100, actuates the motor 1110 to rotate the drive gear 1140 in a first direction, such as an anti-clockwise direction. The drive gear engages with and drives the driven element 1150 in a second direction, such as a clockwise direction. The driven element 1150 is rotated to an extent that an contact surface of the driven element presses against an adjacent contact surface /side region of the toggle arm 1121 and pushes against the toggle arm to rotate the toggle in the same direction as the driven element 1150 until the toggle 1120 reaches the first / neutral position. One or more position sensors signal to the controller 3000 that the toggle has reached the desired neutral position and the controller stops the motor or reverses the motor to return the driven element to its neutral position.

As above, rotation of the toggle 1120 causes the transmission link 1210 to move in the same direction, which rotates the transmission levers 1130a, 1130b in the same direction, causing simultaneous rotation of the control elements 1220a, 1220b to change the castors 2200 from drive mode to neutral mode. The pedals 1240 are also caused to rotate to adopt the neutral position.

Again, after the toggle 1120 reaches the neutral position, the controller 3000 may reverse the motor to rotate the drive gear 1140 and the driven element 1150 in the reverse directions until the driven element 1150 returns to the centred / home / neutral position, as shown in Figure 6b. One or more position sensors signal to the controller 3000 that the driven element has reached the desired neutral position and the controller stops the motor.

In each case, to return the toggle 1120 to its neutral position (located between two other positions), the driven element 1150 must over-rotate to a position beyond its own neutral position. The controller 3000 may then reverse rotation of the driven element 1150 until the driven element reaches its own neutral position, in which the toggle arm 1121 is located substantially centrally between the opposing contact surfaces of the driven element 1150.

In other forms, as shown in Figures 7 to 10b, the castor control system may be adapted to operate the castors in two modes: such as a brake mode and a neutral mode or a brake mode and a drive mode. In such forms, the toggle is rotatable between a first position and a second position. For demonstration purposes, the first position will be designated the brake position and the second position will be designated the neutral position or the drive position, as the case may be. However, it should be appreciated that either the first position or the second position may be the brake position that corresponds to a brake operating mode and that the other position may be a neutral position or a drive position corresponding to a neutral operating mode and a drive operating mode respectively.

In the example shown in Figure 7, the toggle arm 1121 is substantially perpendicular with the transmission link 1210 in the first position, which corresponds to the neutral position of the toggle and the neutral mode of the castors. However, in other forms, the toggle arm 1121 may be substantially perpendicular with the transmission link 1210 in the brake position or drive position and may be off- centre / non-perpendicular to the transmission link when in the neutral position.

As exemplified in Figure 8a, to electrically change the operating mode of the castors from the neutral operating mode to the brake operating mode, the controller 3000, on receiving the desired operating mode user input via the user interface 3100, actuates the motor 1110 to rotate the drive gear 1140 in a first direction in order to rotate the toggle from a first (neutral) position to a second (brake) position. In the example shown in Figure 8a, the first direction is an anti-clockwise direction. The drive gear engages with and drives the driven element 1150 in a second direction, such as a clockwise direction as shown in Figure 8a. The driven element 1150 is rotated to an extent that an contact surface of the driven element presses against an adjacent contact surface /side region of the toggle arm 1121 and pushes against the toggle arm to rotate the toggle in the same direction as the driven element 1150 until the toggle 1120 reaches the second (brake) position. One or more position sensors signal to the controller 3000 that the toggle has reached the desired position and the controller stops the motor (or reverses the motor to return the driven element to its neutral position). As the toggle reaches the desired position, the castors are caused to change to the selected brake or drive operating mode, as the case may be, and as described above. Optionally, as described above, after the toggle 1120 reaches the desired brake position, the controller 3000 reverses the motor to rotate the drive gear 1140 and the driven element 1150 in the reverse directions until the driven element 1150 returns to its centred / home / neutral position, as shown in Figure 8b, without causing further rotation of the toggle 1120. One or more position sensors signal to the controller 3000 that the driven element has reached the desired neutral position and the controller stops the motor.

Although operation of the two-mode control system has been described between the neutral mode and the brake mode, the same operation may be conducted in reverse to change from the brake mode to the neutral mode.

Figures 7 to 8b therefore demonstrate one form of a two-mode castor control system 1000 moving between a first position perpendicular to the transmission link 1210 and a second nonperpendicular / off-centre position. In other forms, the first and second positions of the toggle 1120 may both be off-centre, such that in each position the toggle arm 1121 is non-perpendicular with the transmission link 1210 (i.e. the toggle arm forms an acute angle with the transmission link), as shown in Figures 9a and 10a. For example, the control system 1000 may be configured to operate in a drive mode and a brake mode and so the toggle is moveable between the drive position (as shown in Figures 9a and 9b) and the brake position (as shown in Figures 10a and 10b). In such forms, the toggle 1120 is moved between positions by the driven element 1150 in the same manner as described above in relation to Figures 7 to 8b, but the toggle rotates to a greater extent before reaching the desired second position. Again, once the toggle 1120 reaches the desired position, one or more position sensors signal to the controller 3000 and the controller may stop the motor or may reverse the motor to rotate the drive gear 1140 and the driven element 1150 in the reverse directions until the driven element 1150 returns to the centred / home / neutral position, as shown in Figures 9b and 10b, without causing further rotation of the toggle. One or more position sensors 3200 signal to the controller 3000 that the driven element has reached the desired neutral position and the controller stops the motor.

The toggle preferably rotates up to 90° between the two positions. In preferred forms, the toggle rotates about 30° between the two positions, such as between the neutral position and the brake position. In other forms, the toggle rotates about 60° between the two positions, such as between the brake position and the drive position.

Figures 11 to 16 show manual operation of a castor control system 1000 of the invention, regardless of whether the castor control system is adapted to operate in two modes or three modes. To manually change the operating mode of the castors 2200 from a first / neutral mode, as shown in Figure 2 to a second / brake mode, a user moves one of the pedals 1240 to the brake position, by rotating the pedal in the appropriate direction, as shown in Figure 11. Typically, the pedals 1240 will include at least one visual indication for the user to understand which direction to press the pedal in order to reach the desired operating mode. For example, a first end of the pedal may be coloured red to indicate that depressing the first end will activate the brake mode. A second end of the pedal may be coloured green to indicate that depressing the second end will activate the drive mode.

Rotating the pedal 1240 will cause simultaneous rotation of the respective control element 1220a, 1220b to which the pedal is fixedly connected. Rotation of the control element 1220 causes rotation of the connected transmission lever 1230 in the same direction, resulting in movement of the transmission link 1210 in the same direction, together with the other transmission lever 1230 and control element 1220 (where present), which causes rotation of the toggle 1120 in the same direction and a mode change of the castors 2200 from neutral to brake mode.

In the example shown in Figure 11, the pedal 1240 is rotated clockwise to the brake position, in the direction of arrow A, which causes the transmission link 1210 to be pulled in a first direction and the toggle 1120 to be rotated in the same direction (clockwise in the example shown). Because the driven element 1150 is already in the centred / home / neutral position, the toggle 1120 is able to rotate to the brake position without pressing against the driven element 1150 and causing rotation of the gear system 1130. Thus, the motor 1110 and gear system 1130 remain static. The control elements 1120a, 1120b rotate clockwise with the pedal 1240 and cause the castors 2200 to change to brake mode.

Similarly, Figure 12 exemplifies how to use a pedal 1240 to manually change the castors 2200 from a neutral mode to a drive mode, such a movement typically being applicable to a castor control system adapted to operate in three modes. To affect the mode change, a user presses one of the pedals 1240 to the drive position, by rotating the pedal in the appropriate direction. In the example shown in Figure 12, the pedal 1240 is rotated anti-clockwise to the drive position, which via the control elements and transmission levers, causes the transmission link 1210 to be pulled in a second direction and the toggle 1120 to be rotated in the same direction (anti-clockwise in the example shown). Because the driven element 1150 is already in the centred / home / neutral position, the toggle 1120 is able to rotate to the drive position without pressing against the driven element 1150 and causing rotation of the gear system 1130. Thus, the motor 1110 and gear system 1130 remain static. The control elements 1220a, 1220b rotate anti-clockwise with the pedal 1240 and cause the castors 2200 to change to drive mode.

Figure 13 exemplifies howto use a pedal 1240 to manually change the castors 2200 from a second / brake mode to a first / neutral mode, for operation of both a two-mode castor control system and a three mode castor control system. Figure 14 exemplifies how to use a pedal 1240 to manually change the castors 2200 from a third / drive mode to a first / neutral mode, such a movement typically being applicable to a castor control system adapted to operate in three modes. In both forms, a user rotates one of the pedals 1240 to the desired position for the mode change, which via the control elements and transmission levers, causes the transmission link 1210 to rotate the toggle 1120 to the desired position corresponding to the selected mode. Typically, the driven element 1150 will be in the centred / home / neutral position, so the toggle 1120 is able to rotate to the desired position without pressing against the driven element 1150 and causing rotation of the gear system 1130. Thus, the motor 1110 and gear system 1130 remain static. The control elements 1220a, 1220b rotate simultaneously with the pedal 1240 and cause the castors 2200 to change to the selected operating mode, based on the pedal position.

Figures 15 and 16 exemplify how to use a pedal 1240 to manually change the castors 2200 from a second / brake mode to a third / drive mode and from a third / drive mode to a second / brake mode respectively, for operation of both a two-mode castor control system and a three mode castor control system.

To cause the castors 2200 to move from brake mode to drive mode, as shown in Figure 15, the pedal 1240 is rotated to the drive position (by rotating the pedal anti-clockwise in the example shown), which causes the transmission link 1210 to be pulled in the second direction and the toggle 1120 to be rotated in the same direction (anti-clockwise in the example shown) until the toggle reaches the drive position. Because the driven element 1150 is typically already in the centred / home / neutral position, the toggle 1120 is able to rotate to the drive position without pressing against the driven element and causing rotation of the gear system 1130. Thus, the motor 1110 and gear system 1130 remain static. The control elements 1220a, 1220b rotate (anti-clockwise) simultaneously with the pedal 1240 and cause the castors 2200 to change to drive mode.

To cause the castors 2200 to move from drive mode to brake mode, as shown in Figure 16, the pedal 1240 is rotated to the brake position (by rotating the pedal clockwise in the example shown), which causes the transmission link 1210 to be pulled in the first direction and the toggle 1120 to be rotated in the same direction (clockwise in the example shown) until the toggle reaches the brake position. Because the driven element 1150 is already in the centred / home / neutral position, the toggle 1120 is able to rotate to the brake position without pressing against the driven element and causing rotation of the gear system 1130. Thus, the motor 1110 and gear system 1130 remain static. The control elements 1220a, 1220b rotate (clockwise) simultaneously with the pedal 1240 and cause the castors 2200 to change to brake mode.

By programming the controller to ensure that the driven element 1150 always automatically returns to the substantially centred / home / neutral position, once the toggle reaches the desired position according to the received user input, such that the motor 1110 and gear system 1130 remain static when the pedals 1240 are manually moved between positions, it is possible to use the pedals to manually operate the castors without impacting on the motor. This is a key advantage of the castor control system 1000 invention as, even without power, full manual operation of the castor control system is possible whilst the driven element is in the substantially centred / home / neutral position.

Such an arrangement may require the employment of one or more position sensors 3200 (as described above) to sense the position of one or more components of the castor control system 1000, and to therefore determine the operating mode of the castors 2000. The sensor(s) 3200 may sense the position of any one or more of the drive gear 1140, the driven element 1150, the toggle 1120, the transmission link 1110, a transmission lever 1130, the rotational position of a control element 1220, or the position of a pedal 1240. Each of the one or more position sensors 3200 transmits a signal corresponding to the sensed position to a data processor of the controller 3000, which receives and processes the data to determine the position of the sensed component and to determine the operating mode of the castors 2000.

Any suitable position sensor may be used to directly or indirectly sense the position of the toggle and/or the driven element, as will be appreciated by a person skilled in the art.

In some forms, as shown in Figure 2b, the system 1000 comprises two position sensors: an optical encoder sensor, and a limit switch. The optical encoder sensor comprises a rotatable encoder wheel 3200a mounted on the toggle 1120 and comprising a series of peripheral teeth or crenulations and in which a gap is provided between adjacent teeth / crenulations. The optical encoder sensor also comprises an optical sensing device 3200b that senses the position and speed of the encoder wheel 3200a by sensing light passing through the gaps in the encoder wheel 3200a in the usual way of optical encoder sensors. The limit switch comprises a toggle switch 3200c and two limit stops 3200d, 3200e. The limit stops 3200d, 3200e are preferably mounted on the toggle 1120. The optical encoder sensor may be used to sense the position and speed of rotation of the toggle 1120 (orthe driven element 1150). The limit switch is adapted to sense when the toggle 1120 (or driven element 1150) reaches its maximum angle of rotation in the clockwise and anti-clockwise directions. In effect, the limit switch is used to detect when the toggle 1120 or driven element 1150) reaches an end position (such as the brake and drive positions) and will signal to the controller 3000, which causes the controller to stop the motor when either of the end positions (brake position or drive position) is reached, or causes the controller to reverse the motor to return the driven element to the neutral position, but to leave the toggle in its new position. The sensors 3200 transmit the sensed information to a data processor of the controller 3000, which receives and processes the data to determine the position of the toggle. Once the position of the toggle 1120 is known then the operating mode of the castors 2000 is known.

In some forms, as shown in Figures 2a and 2c, the castor control system may comprise a magnet and hall-effect sensor arrangement in which the magnet and hall-effect sensor are located to sense the position of the driven element (orthe toggle) directly or indirectly and to signal the controller accordingly. For example, a magnet 1154 may be located on the driven element at a location that aligns with a virtual line that runs substantially centrally between the contact surfaces of the driven element 1150. A halleffect sensor (as a position sensor) may be situated at any suitable location, such as on the chassis, the support frame, or the motor. The magnet may trigger the hall-effect sensor to signal the controller 3000 when the magnet 1154 substantially aligns with the hall-effect sensor when the driven element 1150 is in the centred, home/neutral position. In some forms, the hall-effect sensor may be located on a printed circuit board 3300 together with the limit switches and the optical encoder sensor. In such an arrangement, the controller may be programmed to stop the motor after the hall-effect sensor signals to the controller that the driven element is in its neutral position.

The invention also provides a method of operating the castor control system 1000 to manually backdrive the motor 1110 when the castors 2200 are in a particular position, such as the brake position, and power from the motor 1110 has been lost. The method comprises manually rotating at least one pedal 1240 of the castor control system 1000 into the neutral or drive positions, as described above, such that the transmission system causes the castors 2200 to adopt the corresponding neutral or drive operating mode.

Thus, in some forms, the invention provides an electro-mechanical castor control system for a wheeled apparatus comprising a chassis comprising a plurality of castors adapted to operate in at least two different operating modes, including a brake mode. The castor control system comprises a rotatable toggle that is operably engageable with a rotatable driven element driven by a motor to rotate the toggle between at least two different positions, selectable by a user via a user interface. The castor control system also comprises a transmission system comprising a transmission link, a first control element, and a first transmission lever. The toggle may be rotatably connected to the chassis or to a support frame of the wheeled apparatus and to the transmission link, to move / translate the transmission link in opposing first and second directions upon rotation of the toggle. The first control element is operably engaged with at least one castor and comprises a major axis about which the control element is rotatable to change the operating mode of the at least one castor. The first transmission lever is rotatably connected to the transmission link and fixedly connected to the first control element to translate movement of the transmission link to rotational movement of the first control element and vice versa. At least one pedal is fixedly connected to the first control element and is rotatable between positions corresponding to the different operating modes of the castors. The driven element is supported by the chassis or a support frame of the wheeled apparatus and is rotatable by the motor in a first direction to reach a first position, and in a second direction to reach a neutral position. At least one position sensor is adapted to sense whether the driven element has reached the first position or the neutral position. A programmable controller is adapted to receive a user input via the user interface to operate the motor to rotate the driven element in the first direction according to the received user input, and to receive signals from the at least one position sensor to cause the motor to rotate the driven element in a second direction, opposite to the first direction, once the sensor signals that the driven element has reached the first position. The controller is programmed to stop the motor once the sensor signals that the driven element has reached the neutral position, in which manual operation of the pedal allows rotation of the first control element without engaging the motor, so as to avoid back-driving the motor.

In some forms, the motor of the castor control system 1000 is a back-driveable motor, so that if the power to the motor 1110 is lost, or the motor fails, after the toggle 1120 has been moved to a certain position, such as the brake position, and before the motor 1110 has returned the driven element 1150 to the centred / home / neutral position, then the motor allows a user to rotate a pedal 1240 to a desired position (such as from the brake position to a neutral position or a drive position), which rotates the control element(s) 1220 and transmission lever(s) 1230, moves the transmission link 1210, and rotates the toggle 1120 to the desired position. As the toggle 1120 rotates to the desired position, the toggle arm 1121 presses against the adjacent contact surface of the driven element 1150, causing the driven element to rotate in the same direction as the toggle. The driven element 1150 engages with the drive gear 1140, which is therefore also caused to rotate and back-drive the motor 1110. By using a back-driveable motor, the motor 1110 can withstand being back-driven to some extent, while the user experiences some increased resistance when rotating the pedal in order to back-drive the motor. Rotation of the control element(s) 1220 by rotation of the pedal(s) 1240 changes the operating mode of the castors 2200 from brake mode to the selected neutral mode or drive mode, as the case may be. The same approach may be taken to change between any of the operating modes of the castors 2200 after power has been lost or the motor has failed before the driven element 1150 has returned to its home position. Thus, the castor control system 1000 of the present invention provides a method by which to manually override the motor 1110 in the event of motor failure or power failure before the driven element has adopted the home position and without causing significant damage to the motor.

The override feature of the invention is particularly useful if the castors 2200 are locked in brake mode. By operating at least one foot pedal 1240 to move the pedal from a brake position to a neutral position or drive position and back-driving the motor, the present invention advantageously allows the castors 2200 of a chassis to be manually reset from brake mode to neutral mode or drive mode in the event of power failure and / or motor failure. Such failures tend to render an otherwise functional wheeled apparatus, such as a hospital bed or stretcher, inoperable as far as maneuverability is concerned.

The castor control system of the invention is also advantageous by allowing multiple foot pedals to be provided on the chassis and to be usable and accessible, yet also allowing for a user to operate just one of the foot pedals to control all castors of the chassis. This means that a user can operate the foot pedal closest to him or her without needing to identify and move to a designated foot pedal to manually change the operating mode of the castors. Where the wheeled apparatus is a hospital bed or stretcher with a castor at each corner, a user can readily access the pedal associated with each castor at any corner of the bed or stretcher, so that manual control of the castors is easily available. This a convenient solution for a user and also enhances safety by allowing for quick manual change of the operating mode, such as quick braking of the castors.

The present invention also provides for integration of the operation of the castor control system with an electric drive wheel system to prevent stranding during relocation. For example, where the wheeled apparatus comprises castors controlled by the castor control system of the invention, and also comprises a powered drive wheel, in the event of the motor battery running flat or a complete electrical failure when the castors are in the brake mode, the operating mode of the castors may be manually reset via manipulation of the pedals. If the drive wheel is down and contacting the ground surface, there is no manual mechanical system available to raise or retract the drive wheel. However, the drive wheel is capable of rolling forwards and backwards, so once the castors are set to drive mode or neutral mode, the wheeled apparatus can be maneuvered.

The castor control system 1000 is particularly suitable for use with a patient transport apparatus. As such, the present invention also relates to a wheeled apparatus, such as a patient transport apparatus, comprising a castor control system 1000 of the invention.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Although the invention has been described by way of example, it should be appreciated that variations and modifications may be made without departing from the scope of the invention as defined in the claims. Furthermore, where known equivalents exist to specific features, such equivalents are incorporated as if specifically referred in this specification.

Claims

WHAT WE CLAIM IS:

1. An electro-mechanical castor control system for a wheeled apparatus comprising a frame supported by a chassis comprising a plurality of castors adapted to be operated electrically and mechanically in at least two different operating modes, including a brake mode, the castor control system comprising: a rotatable toggle that is operably engageable with a rotatable driven element driven by a motor to rotate the toggle between at least two different positions, selectable by a user via a user interface; a transmission system comprising a transmission link, a first control element, and a first transmission lever; the toggle being rotatably connected to the frame or chassis and to the transmission link, to slidably move the transmission link in opposing first and second directions upon rotation of the toggle; the first control element being operably engaged with at least one castor and comprising a major axis about which the control element is rotatable to change the operating mode of the at least one castor; the first transmission lever being rotatably connected to the transmission link and fixedly connected to the first control element to translate movement of the transmission link to rotational movement of the first control element and vice versa; and at least one pedal fixedly connected to the first control element and being rotatable between positions corresponding to the different operating modes of the castors; wherein the driven element is supported by the frame or chassis and is rotatable by the motor in a first direction to reach a first position, and in a second direction to reach a neutral position; wherein the driven element comprises a body comprising an opening at least partially defined by a pair of contact surfaces between which at least a portion of the toggle is located; wherein the castor control system further comprises: at least one sensor adapted to sense whether the driven element has reached the first position or the neutral position; a programmable controller adapted to receive a user input via the user interface to operate the motor to rotate the driven element in the first direction according to the received user input, and to receive signals from the at least one sensor to cause the motor to rotate the driven element in a second direction, opposite to the first direction, once the at least one sensor signals that the driven element has reached the first position; and wherein the controller is programmed to stop the motor once the at least one sensor signals that the driven element has reached the neutral position, in which the toggle is located substantially centrally between the contact surfaces of the driven element and is spaced from each of the contact surfaces of the driven element, and in which manual operation of the pedal allows rotation of the first control element without engaging the motor.

2. The castor control system of claim 1, wherein the motor is back-driveable such that when both the toggle and driven element are in the first position, manual operation of the pedal causes rotation of the control element by back-driving the motor.

3. The castor control system of claim 1 or 2, wherein the first control element comprises an engagement feature that engages with an engagement feature of the first transmission lever to prevent rotation of the first control element relative to the first transmission lever.

4. The castor control system of any one of the preceding claims, wherein the control element comprises a rod comprising a non-circular lateral cross-section and wherein the first transmission lever comprises a correspondingly shaped opening for snugly receiving a portion of the first control element therein to prevent rotation of the first control element relative to the first transmission lever.

5. The castor control system of any one of the preceding claims, wherein the chassis comprises three castors and the castor control system comprises a second control element and a second transmission lever, each of the first and second control elements being connected to the transmission link by a respective one of the first and second transmission levers, wherein the first control element is operably engaged with two opposing ones of the castors and the second control element is operably engaged with another one of the castors.

6. The castor control system of claim 5, wherein the chassis comprises four castors and each control element is operably engaged with two opposing ones of the castors.

7. The castor control system of claim 5, wherein at least one pedal is fixedly connected to each control element, such that rotation of the first and second control elements causes simultaneous rotation of the pedals, and such that rotation of at least one of the pedals causes simultaneous rotation of the first and second control elements and all of the pedals.

8. The castor control system of any one of claims 5 to 7, wherein each transmission lever is rotatably connected to the transmission link at or near a distal end of the transmission link and wherein the toggle is rotatably connected to the transmission link at a location between the transmission levers.

9. The castor control system of any one of the preceding claims, wherein the driven element comprises a substantially C-shaped body comprising a substantially central opening within which a first end of the rotatable toggle is located, the first end of the toggle and the driven element being independently rotatable about a single axis; and wherein the toggle comprises an arm extending from the first end and terminating at a second end of the toggle, the second end of the toggle being rotatably connected to the transmission link.

10. The castor control system of claim 9, wherein the substantially C-shaped body of the driven element comprises terminal ends adapted to press against the rotatable toggle to rotate the toggle from one position to another.

11. The castor control system of claim 10, wherein the driven element and the toggle are each rotatable between at least two positions.

12. The castor control system of claim 11, wherein the driven element is rotatable between at least three positions, comprising a first position, a second position, and a neutral position;, wherein the neutral position is located between the first and second positions and the toggle is rotatable between at least two of the three positions.

13. The castor control system of claim 12, wherein the driven element and the toggle are each rotatable between all three positions.

14. The castor control system of claims 12 and 13, wherein the toggle rotates between about 30° and about 60° between two of the three positions.

15. The castor control system of claim 14, wherein, when the driven element is in the neutral position, contact surfaces of the driven element are spaced from the toggle at a distance to allow the toggle to rotate between positions without contacting the driven element.

16. The castor control system of claim 15, wherein a first position of the toggle corresponds to a brake mode of the castors, a second position of the toggle corresponds to a drive mode of the castors, and a neutral position of the toggle corresponds to a neutral mode of the castors.

17. The castor control system of any one of the preceding claims, wherein the controller is adapted to receive a user input relating to a selected operating mode via the user interface to change the operating mode of the castors, and to cause the motor to rotate the driven element to press against and rotate the toggle to a position that corresponds with the selected operating mode.

18. The castor control system of claim 19, wherein the controller is programmed to reverse operation of the motor to cause the driven element to return to neutral position after the toggle reaches a position corresponding to a selected operating mode.

19. The castor control system of any one of the preceding claims, wherein the motor and at least a portion of the driven element and toggle are located in a housing together with a second motor for independently powering an electric drive wheel attached to the chassis.

20. The castor control system of any one of the preceding claims, comprising a gear system that comprises a drive gear, rotatable in a clockwise direction and in an anti-clockwise direction by the motor; and wherein the driven element is directly or indirectly engaged by the drive gear to rotate in an anticlockwise direction and in a clockwise direction, the rotatable driven element being adapted to urge the rotatable toggle from one position to another.

21. The castor control system of claim 20, wherein at least a portion of a circumferential surface of the driven element comprises teeth to mesh with teeth of the drive gear.

22. A castor control system for a chassis comprising a plurality of castors, wherein the castor control system comprises: an actuation system comprising a motor operable by a controller and operably engaged with a drive system; a transmission system comprising a first rotatable control element comprising a major axis about which the control element is rotatable, the first control element being operably engaged with the castors, and the transmission system further comprising at least one pedal fixedly connected to the first control element and being moveable between different positions; wherein the transmission system is adapted to transmit rotational output from the motor into rotation of the first control element to electrically change the operating mode of the castors; and wherein the drive system is adapted such that, by moving the at least one pedal from a first position to a second position, the first control element is rotated without engagin the motor, to manually change the operating mode of the castors.

23. The castor control system of claim 22, wherein the at least one pedal is adapted to rotate between a brake position, a drive position, and a neutral position, and wherein each of the brake, drive and neutral positions of the at least one pedal respectively correspond with a brake mode, a drive mode, and a neutral mode of operation of the castors.

24. A wheeled apparatus comprising a chassis comprising a plurality of castors and a castor control system as claimed in any one of the preceding claims.

25. The wheeled apparatus of claim 24, wherein the wheeled apparatus comprises a patient transport apparatus or a trolley.

26. A chassis comprising a plurality of castors and a castor control system as claimed in any one of claims 1 to 23.

27. A method of operating the castor control system of any one of claims 1 to 23, to override the reversible motor when the castors are in a first operating mode, the method comprising moving at least one pedal of the castor control system from a first position to a second position, to rotate the first control element to cause the castors to adopt a second operating mode.

28. A castor control system comprising: a linkage arrangement comprising a plurality of linked members, the linkage arrangement being connected to a plurality of castors attached to a chassis of a wheeled apparatus; and an actuation system connected to the linkage arrangement to move the linkage arrangement between a first position and a second position to change an operating mode of the castors, wherein the actuation system comprises a motor, an actuator, a controller, and a user interface, the user interface being operably connected to the controller, and the controller being adapted to operate the motor according to user inputs received via the user interface, wherein the actuator is operable by the motor to rotate between a first position and a second position, and wherein the rotatable actuator is adapted to engage with a toggle that is rotatably attached to at least one of the linked members to move the linkage between the first and second positions as the actuator rotates.

29. The castor control system of claim 28, wherein the linkage arrangement comprises a transmission link, a first transmission lever, and a first control element comprising a major axis and being rotatable about its major axis; wherein the first transmission lever is rotatably connected to the transmission link and fixedly connected to the first control element; wherein the first control element is operably engaged with at least one of the castors such that rotation of the first control element changes the operating mode of the at least one castor; and wherein the first transmission lever forms the toggle that engages with the actuator.

30. The castor control system of claim 28, wherein the linkage arrangement comprises a transmission link, a first transmission lever, and a first control element comprising a major axis and being rotatable about its major axis; wherein the first transmission lever is rotatably connected to the transmission link and fixedly connected to the first control element; wherein the first control element is operably engaged with at least one of the castors such that rotation of the first control element changes the operating mode of the at least one castor; and wherein the toggle is rotatably connected to the transmission link.

31. The castor control system of any one of claims 28 to 30, wherein the actuator comprises a body comprising an opening at least partially defined by a pair of contact surfaces, wherein at least a portion of the rotatable toggle is located within the opening and between the contact surfaces; and wherein when the actuator rotates such that one of the contact surfaces of the actuator contacts the toggle, the toggle is caused to rotate.