WO2001022912A1

WO2001022912A1 - Stair climbing drive system and vehicles incorporating the drive system

Info

Publication number: WO2001022912A1
Application number: PCT/AU2000/001164
Authority: WO
Inventors: Naixun Liu
Original assignee: LIU JILLY
Current assignee: LIU JILLY
Priority date: 1999-09-28
Filing date: 2000-09-25
Publication date: 2001-04-05
Anticipated expiration: 2002-03-28
Also published as: AUPQ316799A0

Abstract

A drive assembly (10) for a vehicle has a chain (11) passing around a pair of sprockets (12, 13), the lower rim of the chain (11) being supported by a chain guide (14). Bracket assemblies (20) are provided at spaced intervals along the chain (11) and have a ground-engaging wheel (21) rotatably journalled on an axle (22) between a pair of bracket plates (23) mounted on the chain (11) by spaced pins (25). A second pair of spaced pins (26) connect the chain links preceding and succeeding the chain links connected by pins (25) and are received in respective pairs of curved slots (27) in the bracket plates (23).

Description

TITLE:

STAIR CLIMBING DRIVE SYSTEM AND VEHICLES INCORPORATING THE DRIVE SYSTEM

5 BACKGROUND OF THE INVENTION

1 . Field of the Invention

THIS INVENTION relates to an improved drive system,

and to vehicles incorporating the drive system.

The invention is particularly suitable for, but not limited

0 to, a drive system which enables vehicles to negotiate steps, stairs,

escalators or like surfaces.

2. Prior Art

Through the years, there have been many proposals to

enable vehicles to negotiate steps or stairs. Examples include

5 climbing hand trolleys, which have three wheels at the apexes of

rotating triangular brackets; and crawler type tracks which have been

proposed to enable wheelchairs to negotiate stairways.

There is a need for a simple, yet efficient, drive or

support system to enable a wide range of vehicles to negotiate steps

0 or stairs.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a

bracket assembly, mountable on a chain, which can be incorporated into a drive system to enable a vehicle to negotiate steps or stairs.

It is a preferred object of the present invention to provide

such a drive system incorporating one or more of the bracket

assemblies.

It is a further preferred object of the present invention to

provide a vehicle incorporating such a drive system.

It is a still further preferred object to provide such

bracket assemblies which are relatively inexpensive and easy to

manufacture and which can be easily fitted to existing chains with

minimal modification.

Other preferred objects of the present invention will

become apparent from the following description.

In a first aspect, the present invention resides in a

bracket assembly, mountable on a chain of the type having a plurality

of interconnected links, the bracket assembly including:

a pair of spaced, substantially parallel, bracket plates,

with (optional) spacer means therebetween;

wheel or roller means rotatably mounted on axle or shaft

means interconnecting distal ends of the bracket plates; and

at the proximal end, at least two spaced pairs of aligned

holes in the bracket plates to receive shafts or pins interconnecting an

adjacent pair of the links, and at least two spaced pairs of (optionally)

aligned, curved slots to receive the shafts or pins of the preceding and succeeding links, so arranged that the shafts or pins are movable

within the slots as the links pass around a sprocket or travel in a non¬

linear path.

In a second aspect, the present invention resides in a

chain assembly fitted with at least one of the bracket assemblies as

hereinbefore described.

In a third aspect, the present invention resides in a

vehicle having first and second pairs of head and tail, or driving and

driven, sprockets;

a respective chain assembly interconnecting the

sprockets of each pair; and

a plurality of the bracket assemblies, as hereinbefore

described, provided at equally spaced intervals along the chains.

Preferably, the bracket assemblies are provided in aligned

pairs on the chains.

Preferably, four, five, six, eight or n brackets are

provided at equal spacings on each chain where n is an even number

greater than eight.

Preferably, at least one chain guide assembly is provided

between the sprockets of each pair.

The driving sprocket of each pair may be connected to a

manual, electrical, internal combustion, hydraulic (or hydrostatic) or

other suitable propulsion means. BRIEF DESCRIPTION OF THE DRAWINGS

To enable the invention to be fully understood, preferred

embodiments will now be described with reference to the

accompanying drawings in which:

FIG . 1 is a side view of a drive system incorporating four

bracket assemblies in accordance with the present invention;

FIGS. 2, 3 & 4 are respective side elevation, end

elevation and top plan views of one of the bracket assemblies;

FIG. 5 is a schematic side view of a hand cart provided

with the drive system of the present invention;

FIGS. 6 and 7 are similar views showing the hand cart

negotiating a set of steps;

FIG. 8 is a similar view of a luggage carrier;

FIG. 9 is a similar view of a wheelchair; and

FIG . 1 0 is a similar view of a child carrier.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG . 1 , the drive system 1 0 has a chain 1 1

passing around a driving sprocket 1 2 and a driven sprocket 1 3, the

lower run of the chain 1 1 being supported by a chain guide 14

intermediate the sprockets 12, 13. The sprockets 1 2, 1 3 are

provided on respective driving and driven shafts 1 5, 1 6 rotatably

journalled in bushes or bearings (not shown) at respective ends of a

crawler frame 1 7 on which is also mounted the chain guide 14. Four bracket assemblies 20, to be hereinafter described

in more detail with reference to FIGS. 2 to 4, are provided at equal

spacings about the chain 1 1 , and each bracket assembly 20 is

provided with a ground engaging wheel 21 rotatably journalled on an

axle 22 between a pair of bracket plates 23, 24 mounted on the

chain 1 1 via shaft pins 25.

Referring now to FIGS. 2 to 4, each bracket assembly 20

has a pair of bracket plates 23, 24 interconnected by a spacer 26. A

wheel 21 is rotatably mounted on an axle 22 which interconnects the

bracket plates 23, 24 at the distal end of the bracket assembly 20.

The chain 1 1 is received between the bracket plates 23,

24 at the proximal end of the bracket assembly 20, and a pair of

extended shaft pins 25 pass through two pairs of aligned holes in the

bracket plates 23, 24. A second pair of extended shaft pins 26,

connecting the links preceding and succeeding the chain links

interconnected by shaft links 25, are received in respective pairs of

curved slots 27 in the bracket plates 23, 24.

The curved slots 27 allow the adjacent chain links to

hingedly move so that the chain 1 1 can pass around the sprockets

1 2, 1 3 or follow a non-linear path. Without the curved slots 27, the

chain links would tend to pull free from the teeth of the sprockets 1 2,

1 3 as the chain 1 1 passes around the sprockets 1 2, 1 3. Referring to FIG. 5, a hand cart 140 has a load

supporting frame 141 and a handle 142. The cart 140 is supported

by a pair of the drive systems 110, each having six wheels 121.

To travel along a substantially even surface, the drive

systems are locked, so that three of the ground wheels 121 on each

drive system 110 engage the supporting surface 150.

As shown in FIG. 6, to move up or down a stairway

160, the sprockets 112, 113 are allowed to rotate and allow the

frame 117 and chain guides 114 to move relative to the chains 111,

as the wheels 121 are blocked by the risers 161 on the stairway 160.

When the cart 140 is moving, the six wheels 121 on each side of the

cart (six pairs of wheels in total) will be in contact with the treads

162 and risers 161 on the stairway 160.

As shown in FIG. 7, three pairs of the wheels 121 are

shown in contact with the stairway 160.

FIG. 8 shows a small luggage trolley 240 where four

wheels 221 are provided on each drive system 210 on the trolley

240.

Again, when moving on a flat floor, the sprockets 212,

213 are locked against rotation and the wheels 221 roll over the floor

and climb the stairway 260 The sprockets 212, 213 are allowed to

rotate to allow the drive systems 210 to operate to thereby enable

the trolley 242 to negotiate the stairs. Referring to FIG . 9, a wheelchair 340 has a seat 345,

and a crank or handle 346 is operably connected (eg., by a chain or

chains) to the driven sprockets 31 2 of the drive systems 31 0 to

enable the person using the wheelchair to negotiate the stairs 360.

It will be readily apparent to the skilled addressee that

the wheelchair 340 may be provided with, eg., an electric motor or

other suitable propulsion sources to propel the drive systems 310, to

enable the wheelchair 340 to negotiate the stairway 360.

FIG. 1 0 illustrates a child carrier 440 where each drive

system 41 0 has five ground wheels 421 .

It will be readily apparent to the skilled addressee that

the drive systems of the present invention enable the vehicles, to

which the drive systems are fitted, to easily negotiate both flat

surfaces and to climb steps or stairways. As hereinbefore described,

propulsion for the drive systems may be manual, eg., by pushing or

hand-operated crank, by electric motor or other suitable propulsion

means.

The number of bracket assemblies provided for each

drive system can be varied to suit the intended load capacity of the

vehicle to which the drive systems are fitted.

Various changes and modifications may be made to the

embodiments described and illustrated without departing from the

present invention.

Claims

CLAIMS:

1 . A bracket assembly, mountable on a chain of the type

having a plurality of interconnected links, the bracket assembly

including:

a pair of spaced, substantially parallel, bracket plates,

with (optional) spacer means therebetween;

wheel or roller means rotatably mounted on axle or shaft

means interconnecting distal ends of the bracket plates; and

at the proximal end, at least two spaced pairs of aligned

holes in the bracket plates to receive shafts or pins interconnecting an

adjacent pair of the links, and at least two spaced pairs of (optionally)

aligned, curved slots to receive the shafts or pins of the preceding

and succeeding links, so arranged that the shafts or pins are movable

within the slots as the links pass around a sprocket or travel in a non-

linear path.

2. A chain assembly fitted with at least one of the bracket

assemblies as claimed in claim 1 .

3. A vehicle having first and second pairs of head and tail,

or driving and driven, sprockets;

a respective chain assembly interconnecting the

sprockets of each pair; and a plurality of the bracket assemblies as claimed in claim

1 , provided at equally spaced intervals along the chains.

4. A vehicle as claimed in claim 3, wherein:

the bracket assemblies are provided in aligned pairs on

the chains.

5. A vehicle as claimed in claim 4, wherein:

four, five, six, eight or n brackets are provided at equal

spacings on each chain where n is an even number greater than

eight.

6. A vehicle as claimed in claim 4 or claim 5, wherein:

at least one chain guide assembly is provided between

the sprockets of each pair.

7. A vehicle as claimed in claim 6, wherein:

the driving sprocket of each pair may be connected to a

manual, electrical, internal combustion, hydraulic (or hydrostatic) or

other suitable propulsion means.

8. A vehicle as claimed in any one of claims 3 to 7 wherein:

the first and second pairs of sprockets are locked against

rotation with at least the wheel or roller means of at least one pair of

the bracket assemblies, or each chain assembly, operable to support

the vehicle.

9. A vehicle as claimed in any one of claims 3 to 8 wherein:

the vehicle is a hand cart, luggage carrier, a wheelchair

or child carrier.

1 0. A vehicle as claimed in any one of claims 3 to 9 wherein:

when the vehicle moves up or down a stairway, the

chain assembly (and chain guide assemblies) move relative to the

wheel or roller means held stationary by the stairway.

1 1 . A vehicle as claimed in any one of claims 3 to 1 0

wherein:

the vehicle has a chassis or frame; and

the pair of sprockets are provided on a spaced pair of

axles or shafts on the chassis or frame; and

the chain guide assemblies are mounted on the chassis

or frame to at least support a lower rim of the chain of a respective

chain assembly between the pair of sprockets for the chain assembly.