WO2011004178A1

WO2011004178A1 - Braking system for transportation device

Info

Publication number: WO2011004178A1
Application number: PCT/GB2010/051086
Authority: WO
Inventors: Simon Mark Parish; Andrew Farrow
Original assignee: Smirthwaite Ltd
Priority date: 2009-07-04
Filing date: 2010-07-01
Publication date: 2011-01-13
Also published as: GB0911619D0; GB2471659A

Abstract

A braking system (44) for a transportation device (10) having at least one castor assembly (22, 24, 26, 28) rotatably mounted on the transportation device, which castor assembly is provided with a wheel (38) rotatably mounted within the castor assembly, which braking system comprises: a braking mechanism for restricting rotatable movement of the castor assembly with respect to the transportation device; a braking element for restricting rotatable movement of the wheel with respect to the castor assembly; and an actuator for actuating the braking mechanism and the braking element; the arrangement being such that actuation of the actuator causes activation of the braking mechanism and of the braking element.

Description

Braking system for transportation device.

The present invention relates to a braking system for a

transportation device, such as a wheel chair, special needs chair, buggy, trolley or hospital or long-term care bed. In particular, the present invention relates to a braking system for such a transportation device, which may be operated by the user of the transportation device. Disabled children and adults often require specialised

transportation devices, mobility devices or patient support apparatus, such as chairs with wheels to assist mobility. The wheels of such devices are usually mounted in a castor assembly, which is rotatably mounted with respect to the device, so that the wheels are capable of rotational movement in two opposing planes allowing a greater freedom of movement for the device. Devices of this type are designed to be moved from location to location. Castors allow the device to be rolled and steered between locations. During movement free rolling castors are required but when the device is in its desired location a brake should be applied to the castors to maintain the device

stationary at that location. It is, therefore, desirable to provide the transportation device with a user operable mechanism for applying brakes to the castors or wheels of the

transportation device.

Known hospital bed braking systems having an anti-swivel or directional lock mechanism are able to block rotation

(swivelling) of the castor assembly with respect to the bed by blocking swivelling of the castor wheel fork. Generally there is provided a separate anti-swivel brake for each castor. WO 00/51830 discloses a braking system for a hospital bed where the individual anti-swivel brakes are coupled to a linkage device so that actuation of one of the brakes causes the others to be actuated so that all four brakes can be actuated simultaneously. These anti-swivel brakes merely act to prevent swivel of the castor with respect to the bed frame. A separate brake system (a wheel brake) is used to prevent rotation of the wheel within the castor assembly and the two brake systems work in

opposition; they cannot be used at the same time as each other.

The braking systems of known special needs chairs for disabled persons generally stop motion of wheel, e.g. by means of a cam located about the caster. One known braking system includes a metal bar attached to the frame of the chair, which when pushed down onto the floor lifts the chair upwards, taking the weight off the castors, lifting them off the floor to prevent movement on the frame on the castors. The castors themselves are not locked with respect to movement relative to the frame. There is a need for improvements in known braking systems for transportation devices.

According to the present invention there is provided a braking system for a transportation device having at least one castor assembly rotatably mounted on the transportation device, which castor assembly is provided with a wheel rotatably mounted within the castor assembly, which braking system comprises:

a braking mechanism for restricting rotatable movement of the castor assembly with respect to the transportation device; a braking element for restricting rotatable movement of the wheel with respect to the castor assembly; and

an actuator for actuating the braking mechanism and the braking element;

the arrangement being such that actuation of the actuator causes activation of the braking mechanism and of the braking element.

The present invention is advantageous as it provides a total lock system by which both swivelling of the castor and rotation of the wheel is achieved by one easy actuation procedure.

Secure locking of the transportation device against movement is thereby achieved. The present invention provides ease of use. It is preferred that actuation of the actuator causes activation of the braking mechanism and of the braking element

substantially simultaneously. The actuator activates and deactivates the braking system. The actuator causes the braking mechanism and braking element to move between a first position in which free movement of the castor assembly or wheel is allowed and a second position in which movement is restricted. It is preferred that a braking mechanism and a braking element is provided for each castor assembly present on the

transportation device and that the arrangement is such that activation of the actuator causes activation of each and every braking mechanism and braking element so that movement of each and every castor assembly is prevented by use of a single, common actuator.

The braking system preferably comprises brake co-ordination means for linking the operation of the braking mechanism with the operation of the braking element. The brake co-ordination means may take the form of a braking co-ordination member operably linked to the braking mechanism and to the braking element. The braking co-ordination member may be in operable contact with both the braking element and at least a part of the braking mechanism and through that contact is able to urge the braking element or braking mechanism into operation. The braking co-ordination member may be integrally formed with either the braking element or at least a part of the braking mechanism. Alternatively the raking element may be integrally formed with at least a part of the braking mechanism and the braking co-ordination member may be in operable contact with that integral part of the braking system.

The braking mechanism may take the form of complementary-shaped braking members provided with co-operating surfaces that allow the brake members to become engaged with each other. When one of the brake members is mounted fixedly with respect to the transportation device and the other mounted on the rotatably mounted castor assembly engagement of the brake members causes the castor to be locked against rotatable movement with respect to the transportation device. To be capable of interacting the brake members may be provided with male and female elements for mating together. As an example one braking member may be provided with one or more detent or aperture (locking hole) into which a corresponding tab or projection (locking pin) on the other braking member may be snugly received. A plurality of such mating elements may be provided. The braking members may be mounted in the braking system so as to be moveable in opposition to each other; movement away and towards each other leading to engagement and disengagement of the braking members. Means may be provided for urging the brake members into their unlocked, disengaged position.

The braking element may take the form of a brake lever, brake cam or brake pad provided with a surface that can be urged against the circumference of the wheel to thereby prevent it from rotating with respect to the castor support. The brake element may be pivotably mounted on the castor assembly so that it can be pivoted towards and away from the bearing surface of the wheel. The braking element may take the form of a caliper braking element having complementary braking surfaces between which the sides (rim) of the wheel is held to restrict rotation of the wheel. Means may be provided for urging the brake element away from the wheel into an unlocked, disengaged position .

According to the present invention there is also provided a for a transportation device, which transportation device comprises: a support to accommodate a person;

at least one castor assembly rotatably mounted on the transportation device, which castor assembly is provided with a wheel rotatably mounted within the castor assembly; and a braking system according to the present invention.

A further or first aspect of the invention provides a

transportation device, comprising:

a support to accommodate a person;

three or more wheels; and

a braking mechanism on each of two or more of said wheels; an actuator positioned to be operable by a person occupying the support, wherein operation of the actuator actuates the braking mechanisms simultaneously.

The invention thereby allows the user of the transportation device to simultaneously operate the brakes on all of the wheels, providing the user safe control of the transportation device.

The transportation device may comprise a base or frame. The position of the support may be adjustable relative to the base, for example the height may be adjustable.

The support may comprise a seat or a bed. For example a transportation device comprising a special-needs chair, wheel chair or buggy would comprise a seat, whereas a hospital trolley would comprise a bed. The support may include a seat or bed base substantially horizontally positioned. It may be provided with vertical supports, e.g. seat back, arm rests, head or side rails .

The actuator may be mounted on the support or in a fixed position relative to the support. This has the advantage that the position of the actuator relative to the support remains the same, whatever the adjustment of the support position. The actuator may be mounted to the support, e.g. seat base, by means of a mounting member such as a bracket or flange. The actuator may be advantageously positioned so as not to interfere with a user's body during use and during transfer in and out of the transportation device.

The actuator may comprise a gross motor device; this involves the use of the big muscles in the body, including arms and abdomen, as opposed to fine motor, which involves the use of small muscles of the body, such as hands and fingers. Pushing the actuator down to apply the brakes therefore has the

advantage of using body weight. A spring mechanism may be used to bias the actuator arm back to its upper position, to make releasing the brakes easy.

To prevent accidental operation of the brake system the actuator may be provided with means for locking it into the non-braking position. Where the actuator is a lever that lever may be located in a housing having a recess into which the lever can be locked into position, e.g. an inverse L-shaped recess.

In one embodiment, the actuator comprises a lever mechanism, for example a lever housing and lever arm. The lever arm may have a first position in which the braking mechanisms are activated and a second position in which the braking mechanisms are not activated. The lever arm may be pushed downwards to activate the braking mechanisms. The lever arm may be held in the downwards position by pushing it into a transverse recess.

The actuator may alternatively comprise alternatives to levers, for example a winding handle or hydraulic system. A user with hand or arm limitations may not be able to operate a lever requiring substantial leverage, alternative actuators may, therefore, be provided such as an electronically operated actuator. Actuation may be by means of a switch. Such an actuator may be operated by a solenoid mechanism. The actuator is operably linked to the braking mechanism and braking element. It may be so linked via a cable system, such as a cable pulley system. Means may be provided for controlling the cable tension.

The transportation device is provided with at least one wheel. It is preferably provided with plurality of wheels, e.g. three or more wheels. At least one of the wheels is mounted in a castor assembly. Preferably each wheel is mounted in a castor assembly. The castor assembly may include a castor support or frame and a wheel rotatably mounted in the castor support or frame. The castors may comprise swivelling castors. The braking system acts to lock each castor in two degrees of freedom. The plurality of wheels may comprise three or more wheels, e.g. four wheels, for example four castors.

The braking mechanisms may be arranged such that the braking mechanism can also be activated individually at each wheel, for example by using an individual brake actuator, such as a brake pedal, at each wheel.

The braking mechanism may be cable actuated. Cable actuation gives ease of operability. A braking cable may be provided for each braking mechanism and an actuator cable may be provided for the actuator. A junction box may be provided to connect the actuator cable with the plurality of braking cables, so that actuation of the actuator cables actuates all the braking cables . The braking system is preferably mounted with respect to the transportation device so as to give adequate ground clearance.

The transportation device may comprise, for example, a special needs chair, wheel chair, buggy or trolley. A further or second aspect of the invention provides a

transportation device, comprising:

a base comprising three or more wheels;

a support to accommodate a person, the position of the support being adjustable relative to the base;

braking mechanisms on two or more of said wheels;

a user operable actuator for actuating the braking mechanism on said two or more wheels simultaneously, which is positioned to be accessible to a person on the support;

wherein the user operable actuator remains in the same position relative to the support, however the support is adjusted.

A further or third aspect of the invention provides a

transportation device, comprising:

a base comprising three or more wheels;

a support to accommodate a person;

brakes on two or more of said wheels;

a user operable actuator, which is positioned to be accessible to a person on the support;

individual brake actuators on each wheel;

wherein the braking mechanisms may be operated simultaneously by the user operable actuators or individually by the individual brake actuators.

Operation of the individual brake actuators could be carried out by a second party, for example a carer or attendant.

A further or fourth aspect of the invention provides a braking system for a transportation device having a plurality of wheels, the braking system comprising:

two or more braking mechanisms for applying a braking force to said two or more wheels;

a common actuator for actuating said two or more braking mechanism simultaneously; one or more individual brake actuators, each individual brake actuator operating an individual braking mechanism;

wherein the braking mechanisms may be actuated either simultaneously by the common actuator or individually by the individual brake actuators.

A further or fifth aspect of the present invention comprises a transport device having a plurality of wheels, the

transportation device comprising the braking mechanism described in the fourth aspect.

Preferred features of the second, third, fourth and fifth aspects of the invention may be as described above in connection with the first aspect or any other aspects of the invention. Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", mean "including but not limited to", and do not exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Other features of the present invention will become apparent from the following example. Generally speaking the invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any

accompanying claims and drawings) . Thus features, integers, characteristics, compounds, chemical moieties or groups

described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. Moreover unless stated otherwise, any feature disclosed herein may be replaced by an alternative feature serving the same or a similar purpose.

The present invention will now be described by way of example only and with reference to the accompanying illustrative drawings, in which:

Figure 1 shows a front view of the special needs chair; Figure 2 shows a rear view of the special needs chair;

Figure 3 illustrates a castor for use in the special needs chair;

Figure 4 illustrates the braking mechanism for use in the castor of Figure 3;

Figure 5 is a rear view of the base of the special need chair; Figure 6 illustrates the junction box of the braking mechanism of the special needs chair;

Figure 7 illustrates the lever mechanism of the special needs chair; and

Figure 8 illustrates a top view of the arm of braking mechanism illustrated in Figure 4.

Figures 1 and 2 show front and rear views of a transportation device, a special-needs chair 10 according to the present invention. The chair 10 has a support, seating portion 11, and a base 20. The seating portion comprises a seat 12, arm rests 14,16 and back rest 18. The height of the arm rests 14,16 and back rests 18 are adjustable to accommodate the user.

The base 20 has a pillar 30 which supports the seating portion 11. The pillar 30 allows vertical adjustment of the seat 12. The vertical adjustment may be by conventional means and is not described in detail here. The base is supported by four castor assembles 22,24,26,28.

Figure 3 is a side view of one of the castor assemblies. The castor assembly comprises a mounting member 32 attached to the base of the support, a castor support or frame in the form of a fork 34 rotatably mounted to the mounting member 32, an axle 36, wheel 38, brake mount 40 and brake pedal 42. The castor assembly allows rotation about two axes; firstly rotation of the wheel 38 about the axle 36, as illustrated by arrow A and secondly rotation of the fork 34 relative to the mounting 32, as

illustrated by arrow B. A brake pedal 42 allows a brake to be applied to the surface of the wheel 38 independently of the actuator to be described below.

Figure 4 shows the braking system 44 including a braking mechanism used to restrict movement of the castor assembly of Figure 3 with respect to the support of the transportation device on which it is rotatably mounted. The braking system also includes a braking element in the form of brake pad 46 which contacts the wheel 38 when the braking mechanism is actuated, thereby applying friction to the wheel.

The braking mechanism includes complementary-shaped braking members provided with co-operating surfaces that allow the brake members to become engaged with each other. The braking members take the form of two part rings 48, 50 provided with an

engagement surface having a plurality of projections and detents that give a "castellated" surface. The first braking member, castellated part ring 48, is located within the mounting member 32 in a fixed position relative to that mounting member. The second braking member, castellated part ring 50, is located within the castor support, fork 34. It is operably linked to the brake element, brake pad 46, via part of the braking co- ordination means, a linking member, arm 52. In this embodiment one of the braking members, castellated part ring 50, is integrally formed with the braking element, brake pad 46, and the linking member. Figure 8 illustrates a top view of the linking member, arm 52, with one of the braking members, castellated part ring 50, at one end and braking element, brake pad 46, at the other. The linking member, arm 52, is pivotably mounted with repect to the castor support frame. The arm 52 includes a spigot 51,53 at each side, which fit into recesses in the fork 34 (not shown) to act as a pivot. The braking co-ordination means also includes a braking coordination member in the form of plate 54. A first end of the braking co-ordination member, plate 54, is operably linked to the braking element. It is located just above the region of the arm 52 at or close to the brake pad. The braking co-ordination member is operably linked to the one of the braking members. A second end of the plate 54 is located below the second

castellated part ring 50. In this embodiment the braking coordination member is in contact with the braking element; a first region 60 of the braking co-ordination member, plate 54, which region extends between the brake pad 46 and spigots 51,53, projects (is folded) over the top of the linking member, arm 52. A second region 62 of the plate, which region extends between the spigots 51,53 and the second castellated part ring 50, projects (is folded) under the linking member, arm 52. A cable 58 extends through the braking mechanism, i.e. through the centre of both castellated part rings 48,50, and then is operably linked to the braking co-ordination member as it connects with the plate 54 below the second castellated part ring 50. A spring 56 is provided around the cable between the second castellated ring 50 and the plate 54. The spring 56 biases the braking co-ordination member, plate 54, away from the braking member, second castellated ring 50.

The linking member, arm 52, is provided in this embodiment with means for biasing the brake element into its non-braking position. Here the biasing means is integral with the linking member. The linking member, arm 52, has a central tongue 55 which extends from the braking element, brake pad 46, to a free end 57 towards the castellated part ring 50. In use this free end of the tongue is held out of the plane of the arm 52 against a fixed part of the castor assembly (not shown) . This tongue acts to bias the arm 52 and thereby biases the braking element away from the wheel.

The braking system has two methods of operation. Firstly, the braking system can be operated by using the brake pedal 42 on the castor assembly. By applying downwards force to the brake pedal 42, the brake pad 46 is pushed against the wheel 38, causing a braking action on rotation of the wheel 38 about the axle 36 (arrow A) . As the brake pad 46 is pushed downwards, part of the braking co-ordination means, the linking member (arm 52), will pivot about spigots 51,53 and one of the braking members, the second castellated part ring 50, will be pushed into contact with the other braking member, first castellated part ring 48. As the two braking members, castellated part rings 48,50 lock together, rotation of the castor support frame (fork 34) relative to the mounting 32 (arrow B) will also be

prevented.

The second method of operation is operated by cable 58. When cable 58 is pulled upwards, the end of the braking co-ordination member, plate 54, that is located under the second castellated ring 50 will be pulled upwards against the bias of spring 56. This upwards movement will push the second castellated ring 50 upwards against the first castellated ring 48. As the cable 58 causes one end of the braking co-ordination member, plate 54, to be pulled upwards, the linking member, arm 52, will pivot about spigots 51,53 and cause portion 60 to push downwards on the end of arm 52 to push the braking element, brake pad 46, against the wheel . By using a cable to operate the braking system, a user seated in the chair can operate the brakes. The invention further enables the user seated in the chair to operate the brakes to multiple castors simultaneously, as described below.

Figure 5 shows a rear view of the base 20 of the chair. A junction box 64 is mounted to the base 20. The junction box is illustrated in more detail in Figure 6. A braking cable 58A, 58B, 58C, 58D extends from the braking systems of each castor to the junction box 64. A fifth actuator cable 66 extends from the junction box 64 to a user operable actuator (not shown) .

Figure 6 shows the four braking cables 58A-D entering the junction box 64; two cables at each end. The cables are

conventional brake cables of the type used in bicycles having a core (e.g. steel) and sheath (e.g. plastic) . For each cable, the cable sheath is fixed at the casing of the junction box, whilst the cable core passes through an aperture in the casing. Inside the junction box, there are provided two free moving elements 68,70. Cable cores 72,74 from two of the cables 58A,B entering a first side of the junction box join to a first element 68, whilst cable cores 76,78 from two of the cables 58C,D entering a second side of the junction box 64 join to a second element 70. The fifth actuator cable 66 is also inserted into the junction box 64. The cable sheath of the fifth cable is fixed at the second element 70, whilst the core 80 of the fifth cable 66 is fixed at the first element 68. A spring 82 is located around the core 80, between the first and second elements 68,70.

Actuation of the fifth cable 66 causes the core 80 to retract in its sheath, in a known manner. This causes the two elements 68 70 to slide towards one another. As the two elements 68 70 slide towards one another, the cores 72-78 are pulled inside the sheaths of all four cables 58A-D simultaneously, causing a braking action in all four braking systems. A combination of the linear arrangement of the junction box and the free floating elements provides a low friction mechanism. The braking systems are operated by a lever mechanism 92, shown in Figures 1 and 2. The lever mechanism is shown in more detail in Figure 7.

The lever mechanism 92 comprises a lever housing 94 and lever arm 96. In this embodiment the he lever housing 94 is mounted to the underside of the seat 12. Alternatively the lever housing could be mounted to the left or right armrests. The fifth cable 66 connects to the lever housing 94, with the cable sheath being fixed to the housing and the cable core being inserted into the interior. On the opposite side of the housing 94 from which the fifth cable connects, there is provided an elongate opening 98 from which the lever 96 extends. The lever arm 96 can be moved between a first position at the upper end of the opening 98 to a second position at the lower end of the opening. The opening is provided with a transverse portion at the bottom, to hold the lever arm in position.

Internally, the cable core is connected to the lever arm 96, such that movement of the lever arm causes the cable core to move relative to the cable sheath.

In use, the lever arm 96 is pushed downwards to actuate the braking system. This pulls on the core of the fifth cable 66, which in turn pulls the two sliding elements 68,70 together in the junction box 64. This has the effect of simultaneously pulling the cables 58A-D on all of the braking systems.

The lever arm 96 is held in this bottom position by pushing it into the transverse groove. The lever may be released by pushing it out of the groove and allowing it to return to its raised position. Although a lever mechanism is described, other user operated actuators could be used. Use of a lever has the advantage that it can be actuated by gross motor action, thus making it easier for many disabled users to operate.

Mounting the lever housing 92 on the seat 12 has the advantage that the lever mechanism remains at the same relative position to the user, whatever the seat height.

A further advantage of the invention is that the braking systems can be operated either by a user in the chair, by use of the lever mechanism 92 (in which case they are operated

simultaneously) , or by a helper by using the individual brake pedals.

The braking system described above may be used for applications other than personal transportation devices.

Claims

1. A braking system for a transportation device having at least one castor assembly rotatably mounted on the

transportation device, which castor assembly is provided with a wheel rotatably mounted within the castor assembly, which braking system comprises:

an actuator for actuating the braking mechanism and the braking element;

2. A braking system according to claim 1, wherein actuation of the actuator causes activation of the braking mechanism and of the braking element substantially simultaneously.

3. A braking system according to claim 1 or 2, wherein a braking mechanism and a braking element is provided for each castor assembly present on the transportation device and that the arrangement is such that activation of the actuator causes activation of each and every braking mechanism.

4. A braking system according to claim 1, 2 or 3, wherein the braking system further comprises brake co-ordination means for linking the operation of the braking mechanism with the

operation of the braking element.

5. A braking system according to any preceding claim, wherein the braking mechanism is in the form of complementary-shaped braking members provided with co-operating surfaces that allow the brake members to become engaged with each other.

6. A braking system according to any one of the preceding claims wherein the braking mechanism is cable actuated.

7. A braking system according to claim 6 wherein a braking cable is provided for the braking mechanism and an actuator cable is provided for the actuator.

8. A braking system according to claim 7 wherein more than one braking mechanism is present and the braking system further comprises a junction box to connect the actuator cable with the more than one braking cable, so that actuation of the actuator cables actuates all the braking cables.

9. A transportation device, which transportation device comprises:

a support to accommodate a person;

at least one castor assembly rotatably mounted on the transportation device, which castor assembly is provided with a wheel rotatably mounted within the castor assembly; and

a braking system according to any one of claims 1 to 8.

10. A transportation device according to claim 9 wherein the transportation device is in the form of a special-needs chair.