GB2285776A - Collapsible wheeled chair or buggy - Google Patents

Abstract

A childs chair comprises a frame 2A, a plurality of leg members 18 pivotally mounted on the frame and at least one threaded drive spindle 8 mounted for rotation on the frame 2 and coupled to each leg member 18, wherein rotation of the drive spindle 8 causes each leg 18 to pivot about its mounting 20 to move the chair from a collapsed state to an expanded state and vice versa. An electric motor may be provided to operate the drive. The backrest 32 is constructed as a plate which folds down on to the seat frame 2A, the legs 18 fold flat against the seat frame, and the leg rest 42A and flap 42 fold over the legs so that the collapsed chair resembles a suitcase and can be taken as hand luggage aboard an aircraft. <IMAGE>

Description

A TRAVEL BUGGY This invention relates to a travel buggy or collapsible chair for a child and in particular to a chair which in its collapsed state is sufficiently compact and lightweight to be used for travelling.

A conventional child's chair or so-called buggy may be arranged to be partially collapsible. This is usually achieved by arranging for the lateral bracing members to be foldable so that the side members may be brought together to produce a more compact package. In this collapsed state, the chair may be more readily stored or transported in a car boot, for example. However, even when collapsed the chair is still difficult to manhandle particularly if other objects and/or a child are being carried at the same time.

In addition, chairs of this type are not permitted by most airlines to be carried on board an aircraft as handluggage. Thus, when travelling by air with a child which requires a chair of this type, the chair must be checkedin before boarding the aircraft and can only be retrieved when the rest of the luggage is brought off the aircraft.

Despite the efforts of airlines to load these chairs into the hold after the rest of the luggage and to unload them first, in practice, a significant amount of time must be spent both before takeoff and after landing dealing with the child without the benefit of the chair. These problems also apply to travel by car, bus, coach and train.

According to the invention, a collapsible chair for at least one child comprises a frame, a plurality of leg members pivotally mounted on the frame, at least one threaded drive spindle mounted for rotation on the frame and at least one actuating piece mounted for axial movement on the spindle, each leg member co-operating with at least one actuating piece, wherein rotation of the drive spindle causes the or each actuating piece to move axially along the or each respective spindle thereby causing each leg member to pivot about its respective mounting to move the chair from a collapsed state to an expanded state and vice versa.

Preferably, the chair collapses to a size which meets the maximum dimension requirements for aircraft hand-luggage and is preferably constructed to have the external appearance and size of a small suitcase or briefcase when collapsed, thus making it possible to take the chair aboard an aircraft as hand-luggage. This size is also a convenient size for storage in a car (on a seat for example), bus, coach or train.

The frame preferably forms the four sides of a rectangle which in the briefcase embodiment may also form at least one of the sides of the case. In this way, the space left inside the frame for the chair mechanism is maximised.

Additionally, the lid of the case may pivot so that its inner surface forms a back for the chair and the base of the case may be removable or at least openable to permit the leg members to extend through it. Preferably the lid and/or base may be opened to permit inspection of the interior by, for example, customs officials. Furthermore, the lid may contain an extendible handle for moving the chair along the ground.

The or each spindle is preferably powered and is preferably operable by a single control which permits onehanded operation of the chair at least to effect movement from the collapsed to the expanded state. The control may typically take the form of a push button which may be locked in the "on" or "expand" position which in conjunction with at least one suitably located limitswitch may permit automatic operation of the chair. The spindle may be electrically powered and the electrical power source is preferably a battery. One solution for powering the spindle is to use the type of motor and gearbox commonly found in a rechargeable screwdriver since this has suitable torque and current drain characteristics, is readily available and is designed to be operated from a rechargeable power source (typically Nickel-Cadmium cells).The control may also in its first portion of operation serve to release the lid and base of the case to allow the chair back to be secured in position and to allow the leg members to extend respectively.

The chair preferably has four leg members arranged in two pairs, each pair of leg members being pivotally mounted at or adjacent a respective side of the frame for rotation about an axis or axes extending generally parallel to the side of the frame, one such respective side being opposite the other such respective side of the frame, Preferably, the actuating pieces are threaded on one or more motordriven spindles extending generally perpendicularly to and between the said respective sides of the frame, generally in a common plane of the said axes of rotation, and each leg member is arranged to co-operate with one of the actuating pieces.The arrangement and the positioning of the spindle and its threaded portions is such that as each actuating piece is moved towards the pivot axis or axes of the associated leg members, the leg members are forced to move out of the plane of the frame to an extended configuration in which the leg members all project on one side of the said plane so that the distal ends of the leg members lie in a second plane spaced from and at least approximately parallel to the plane of the frame. This arrangement yields a particularly compact structure which can fit in a case of a suitable size for aircraft travel and yet can be expanded to a size sufficient to carry a child.

In a first preferred embodiment of the invention, the rotational position of each leg member about its pivot axis is determined by a strut or link member, one end of which is connected to the leg member at a position spaced from its pivotal mounting on the frame and the other end of which is connected to the actuating piece which is reciprocally movable in the frame to pivot the leg member between a retracted position and an extended position.

Each leg member has a respective strut connected to one of the actuating pieces. Preferably there are only two actuating pieces and these are mounted on a single spindle mounted centrally in the frame between and parallel to the third and fourth sides of the frame. Thus as the actuating pieces move towards the pivot axis or axes of the associated leg members, the leg members and the struts are forced to move out of the plane of the frame as described above. In this embodiment, the length of the strut also controls the loci of movement of the pivoting leg members.

In an alternative embodiment of the invention, the leg members are preferably moved into the extended position by the cam operation on a bearing surface of each leg member, of inclined surfaces formed on the actuating pieces.

Preferably four such actuating pieces are provided disposed on a pair of threaded spindles located adjacent the respective third and fourth sides of the frame.

Preferably, at least one of the leg members is sprung so that the bearing surface of the leg member is suitably located to engage the inclined surface of the associated actuating piece before the inclined surface and bearing surface have made contact.

By arranging to decrease the thread pitch (and thereby increase the gear ratio) of the spindle at the carrier positions which substantially correspond to full extension of the leg members and/or by a suitable choice of pivot and link member mounting points, the leg members may conveniently be made to lock in their fully extended position.

The invention will now be described, by way of example, with reference to the drawings in which; Figure 1 shows a plan view of a collapsed chair constructed in accordance with the invention; Figure 1A is an exploded, cross-sectional view of Figure 1 along line A-A; Figure 2 is a cross-sectional view of Figure 1 along line B-B; Figure 3 shows a side view of an expanded chair constructed in accordance with the invention; Figure 4 shows a front view of the chair of Figure 3; Figure 5 shows a side view of a complete chair constructed in accordance with the invention in its collapsed state; Figure 6 shows a side view of a complete chair constructed in accordance with the invention in its partially expanded state; Figure 7 is a plan view of an alternative embodiment in accordance with the present invention; Figure 7A is a sectional view along line A-A of Figure 7;; Figure 8 is a partial sectional view along spindle 8A of Figure 7; and Figure 9 is a reduced-scale side view of Figure 8 showing a complete chair in accordance with the invention.

With reference to Figures 1 and 2, a chair is shown in its collapsed state contained in a case having sides 2A, 2B, a lid and base (not shown) and having the dimensions of a typical briefcase i.e. 120mm x 340mm x 340mm. Four cylindrical frame pieces 4 are mounted inside the case parallel to and adjacent the sides 2B and have their respective outer ends fixed in the sides 2A and their inner ends fixed to two mounting blocks 6 which are fixed approximately midway along the inner face of each respective side 2B.

Joining the two blocks 6 is a threaded spindle which is mounted for rotation in bearings (not shown) formed in each of the blocks 6. The bearings may, for example, be plain, needle and/or roller bearings. Mounted above and partially surrounding the spindle 8 is a grooved track 10 shown in greater detail in Figure 1A. Two carriers 12 run on the track 10 and since the spindle 8 passes through a threaded hole 14 formed in each respective carrier 12, the carriers are caused to move axially along the track 10 when the spindle 8 is rotated. The direction of the thread running through each respective carrier 12 is reversed with respect to the other carrier so that when the spindle 8 is turned, the two carriers 12 move in opposite axial directions.

The spindle is driven by an electric motor and gearbox arrangement 16. This may be of the type used in rechargeable power tools such as screwdrivers since these are readily and cheaply available and have suitable torque and current drain characteristics. One such arrangement is supplied by Escap (Registered Trade Mark) under the part numbers 28L28 (DC motor) and K38 or K40 (gearboxes).

This particular motor is available in several supply voltage configurations and a suitable specification may be chosen by considering the requirements of battery capacity, weight and the number and speed of operations required between battery recharges. The spindle 8 may be coupled to the arrangement 16 using conventional gearing techniques such as a worm drive or a pinion drive. The chair preferably incorporates battery charging circuitry (not shown) including a socket for attaching a mains power supply.

An elongate leg member 18 is pivotally mounted on each respective cylindrical frame piece 4. The pivotal mounting is achieved in each case by means of a collar 20 formed at an end of each leg member 18, having an annular cross-section and which surrounds the frame piece 4. The interior surface of each collar 20 forms a bearing which permits rotation of the leg member 18 about the axis of each respective frame piece 4. The choice of suitable bearings is similar to that of the spindle bearings described above. At the other end of each leg member 18 a hub assembly 22 comprising a braking mechanism 24 is mounted. Each hub assembly 22 carries a wheel 26 for moving the chair over the ground when the leg members 18 are in an extended position as described below.In a preferred embodiment, the batteries may also be charged by means of a generator coupled to at least one of the wheels 26 such that the batteries are charged as the chair is wheeled along.

Each pair of leg members 18 mounted adjacent one of the sides 2B is connected to a respective carrier 12 by a respective elongate link member 28. Each link member 28 is connected between a point on a respective leg member 18 between the hub assembly 22 and the collar 20 and a carrier 12. The arrangement is such that when the spindle 8 is rotated, the axial movement of the carriers 12 along the track 10 and the consequent movement of the link members 28, causes the leg members 18 to pivot about the frame pieces 4. Depending on the direction of rotation of the spindle, the hub assemblies 22 are caused either to extend out of or retract into the plane of Figure 1. To permit the necessary flexion at either end of each link member 28, the connection at each end is achieved using ball joints 30.Depending on the relative positions of the collar 20, the track 10, the angle of extension of the leg members 18, the position of the carriers 12 and the length of the link members 28, the link members 28 may in some cases only need a simple two dimensional pivot at one end. It will be understood by the skilled man that other known means of providing a suitable joint with three degrees of freedom may be used in place of any of the ball joints 30 for example, a resilient block.

With reference to Figures 3 and 4, the leg members 18 may be locked in the extended position shown in these Figures using mechanical locking pins or more advantageously they may automatically be locked by arranging the angles of the leg members 18 and the link members 28 such that in normal use the forces exerted on the leg members 18 through the wheels 26 and transmitted to the spindle 8 via the link members 28 and carriers 12 are insufficient to force the spindle 8 round under the braking action of the motor 16.

Provided the spindle 8 cannot rotate, the leg members 18 cannot revert to their collapsed state. To further enhance this effect, the pitch of the spindle thread may be reduced towards the portion of thread that corresponds to the position of each carrier 12 when the leg members 18 are extended. In this way the gear ratio of the spindle 8 and carrier 12 combination is increased and the braking effect of the motor 16 is correspondingly increased.

With reference in particular to Figure 3, the lid 32 of the case may be released and pivoted back about one of the sides 2B, 2B to the position shown in the Figure to form a back for the chair. The back is held in position by locking back supports 34 which connect the back to the side 2A, 2B about which it pivots.

The case also includes a flexible material such as nylon fixed between the sides 2A or 2B and the lid 32 to form sides 36 for the seat when the lid 32 is pivoted back.

These sides 36 prevent a child falling out of the chair.

To further enhance safety, the chair may also include a lap belt 38 fitted between opposite sides 2A or 2B of the case.

The lid 32 also incorporates a handle 40 which may be telescopically extended from the lid 32 to permit the chair to be moved without having to bend down.

Figure 5 and 6 show a side view of the collapsed chair.

In a preferred embodiment, the first portion of travel of the handle 40 as it is extended has a special significance. This first portion serves to release a catch on each of the lid 32 and two lower flaps 42 forming the base of the case. The lid 32 and flaps 42 are springloaded so that when the catches are released they spring part-way open as shown in Figure 6. This serves to clear the way for the mechanism to extend when the spindle begins to rotate. On the underside of the cranked end of the handle, a push-button trigger 44 is positioned which causes the motor to operate and thereby causes the legs to be extended. Thus the chair may be extended in a onehanded motion by pulling the handle 32 out a small way and simultaneously squeezing the trigger 44 to activate the extension mechanism to extend the wheels.To collapse the chair, the trigger 44 is activated to reverse the motor and thereby to retract the wheels. The flaps 42 and lid 32 may then be pushed shut to be held in under the control of their respective latches.

Advantageously, the flap 42A at the front of the chair may be fixed in position to form a footrest as shown in Figure 3. In an alternative embodiment, at least one of the flaps is arranged to replace at least one of the leg members 18, the respective hub assemblies 22 being mounted directly to the flap 42.

Figures 7 and 8 are views of an alternative embodiment in accordance with the invention. The same reference numerals have been used where appropriate, as those used in Figures 1 and 2.

In the alternative embodiment the single spindle 8 is replaced with two spindles 50A, 50B which are adjacent each of the respective sides 2A. The motor and gearbox arrangement 16 and battery 52 are mounted parallel to the sides 2A and generally centrally between them. The spindles 50A, 50B are driven by a toothed belt 54 which runs around a pulley 56A, 56B provided at an end of each respective spindle 50, around a pulley 58 provided at the end of the motor 16 and around two resiliently mounted tensioning pulleys 60 located adjacent the pulley 58 and for tensioning the belt 54.

Running on each of the threaded spindles 50, 50B is a pair of actuating pieces 62A-1, 62A-2. A cross section through one of the actuating pieces is shown in Figure 7A.

The spindles 50A, 50B are as before, arranged to cause the actuating pieces 62 to move in opposite directions along the spindle as the spindle is rotated. With particular reference to Figure 8, it will be seen that each of the actuating pieces 62 is provided with an inclined surface 64 which co-operates with a bearing surface 66 provided on the inner ends of each of the leg members 18. In the embodiment shown, the bearing surfaces 66 are provided by rollers mounted on axles. The bearing surfaces 66 need not be integral with the leg members 18 and as shown in the Figure may be provided on a cranked member 68 mounted pivotally and coaxially with the pivotal mounting of the leg member 18 such that movement of the actuating pieces 66 causes the cranked members 68 to urge the leg members 18 into their extended position.In Figure -8, the actuating pieces 62, the leg members 18 and the cranked members 68 are shown in several positions in dotted lines.

To provide greater stability and also to allow shopping or other articles to be hung from the handle 40, the rear leg member (on the right side of Figure 8) is preferably inclined backwards at a greater angle than the front leg member 18. Typically the rear leg member is inclined at 30 to vertical and the front leg member is inclined at 15 to vertical. This difference in extension angles together with the need to allow the leg members 18 to extend without collision occurring between the wheels 26 and hub assemblies 22, may require the provision of a spring 70 (shown as a hair spring in Figure 8) to move the cranked member 68 into position ready for engagement by its associated inclined surface 64 once the flaps 42 have been released.Thus when these flaps are released, the spring loaded leg members 18 gently and partially extend under the force of the spring 70. The remainder of the travel is achieved by co-operation between the inclined surfaces 64 and the bearing surfaces 66. It will further be seen that the actuating pieces 62 are provided with non-inclined surfaces 72 which correspond to the position of the bearing surfaces 66 when the legs are fully extended. This provides a locking feature for the leg members 18 in their extended position. To further enhance this effect, the overall gear ratio of the pulleys, belt and gearbox typically amounts to 50 to 1. Thus it is extremely unlikely that forces exerted on the leg members 18 will succeed in turning the motor and thereby allowing the legs to revert to their collapsed state.

The motor 16 is provided with a crank opening 74 which extends through the side 2B and permits hand winding should the motor 16 or battery 52 fail.

With reference to Figure 9, the lid 32 may be released independently of the handle 40 and trigger 44 by a release knob 76 located on the side of the lid 32. This permits a thorough inspection by customs' officials of the contents of the "case" when the chair is in its collapsed condition without needing the chair to be fully extended.

The leg members 18, battery 52 and motor 16 are conveniently mounted on a cast or moulded platform 78 (shown in Figure 7) which extends inwardly of the sides 2.

The platform may incorporate a shoe 80 for each respective leg member which serves to locate the leg member in its extended state and to thereby reduce wear on the interior bearing surfaces of the collar 20.

A comparison between Figures 9 and 3 shows that the alternative embodiment dispenses inter alia with the need for the link members 28 and the ball joints 30. The alternative embodiment further improves on the first embodiment by requiring simpler movement of the leg members 18 and by requiring fewer machined parts.

The components of the chair may be made from any materials having suitable strength, durability and weight characteristics. Typically the sides 2A, 2B may be made from a Magnesium casting chosen for its strength, light weight and resistance to corrosion. The other parts of the extension mechanism may be made from suitable metal alloys or even from plastics materials.

Claims (16)

1. A collapsible chair for at least one child comprising a frame, a plurality of leg members pivotally mounted on the frame, a threaded drive spindle mounted for rotation on the frame and at least one actuating piece mounted for axial movement on the spindle, wherein rotation of the drive spindle causes the actuating piece or pieces to move axially along the spindle, and wherein the leg members are pivotally movable in response to the movement of the actuating piece or pieces along the spindle.

2. A chair according to claim 1, wherein the frame has four sides and is generally rectangular.

3. A chair according to any preceding claim, wherein the or each spindle is electrically powered.

4. A chair according to any preceding claim having four leg members arranged in two pairs, each pair being pivotally mounted at or adjacent a respective side of the frame for rotation about an axis parallel or generally parallel to the side of the frame.

5. A chair according to claim 4, wherein the respective sides are generally parallel and opposite one another and wherein the or each spindle extends generally perpendicularly to and between the respective sides.

6. A chair according to claim 4 or claim 5, wherein the or each spindle extends in a common plane of the said axes of rotation.

7. A chair according to any preceding claim, wherein the rotational position of each respective leg member about its pivot axis is determined by a strut, connected at one end to the respective leg member at a position spaced from its pivotal mounting, and at its other end to an associated actuating piece.

8. A chair according to any of claims 1 to 6, wherein each respective leg member is provided with a bearing surface engageable with an inclined surface of an associated actuating piece, whereby movement of the associated actuating piece causes movement of the respective leg member about its pivot axis.

9. A chair according to any preceding claim comprising a plurality of spindles each having mounted on it, at least one respective actuating piece.

10. A chair according to any preceding claim, wherein the frame comprises at least one abutment surface for stopping the pivotable travel of at least one leg member at its outward extent of travel.

11. A chair according to any preceding claim, wherein the leg members, when fully pivoted out of the frame, are arranged in a diverging configuration in which the distal ends of the leg members are further apart from each other than the proximal ends.

12. A chair according to any preceding claim, wherein the distance between the distal ends of the leg members when fully pivoted out of the frame, is greater then the external dimensions of the frame.

13. A chair according to any preceding claim, comprising a base panel attached to a leg member and forming the base of a receptacle for the chair when the leg member is pivoted fully into the frame.

14. A collapsible chair having leg members foldable into a generally planar configuration and having top and bottom plates each pivotable into a closed position in which each plate lies generally parallel to the planar configuration, and in which when closed, the plates form a receptacle for the planar configuration.

15. A chair according to claim 14, wherein at least one of the plates has an open position in which position it forms a backrest for the chair.

16. A chair constructed and arranged as described herein with reference to the drawings.