GB2501771A

GB2501771A - Trolley

Info

Publication number: GB2501771A
Application number: GB1207983.6A
Authority: GB
Inventors: Christopher Robert Duncan
Original assignee: Numatic International Ltd
Current assignee: Numatic International Ltd
Priority date: 2012-05-04
Filing date: 2012-05-04
Publication date: 2013-11-06
Also published as: GB201207983D0

Abstract

A motorised trolley having improved manoeuvrability for supporting loads for transport over a floor surface, comprises a body portion provided with four spaced-apart wheels 21 disposed at corners of a notional rectangle parallel to the floor surface, and which wheels are arranged to support the body portion on the floor surface, wherein a fifth wheel 24 is disposed within said rectangle and is adapted to be driven so as to move, or assist movement of, the trolley over the floor surface. The fifth wheel 24 may be provided with bias means for urging the fifth wheel against the floor surface when the other corner wheels are in contact with the floor. Preferably all four of the corner wheels 21 are castor wheels.

Description

Trolley The present invention relates to the field of trolleys for carrying loads over a floor surface (including ground surface). Examples include janitorial trolleys, laundry trolleys, hospital trolleys and hotel service trolleys.

The present applicant Numatic.lntemational Ltd (UK) manufactures various trolleys under several product names including VersacaretM and NuKeeperTM.

These trolleys typically have an oblong base tray provided with four castor wheels, one at each corner of the base tray. An upstanding superstructure can include bucket stations, bins, storage cabinets etc. A rear end region of the trolley is provided with a transverse push handle which allows a user to push, pull and steer the trolley over a floor surface.

To improve the directional guidance of the trolley, one end's pair of castor wheels may be replaced by a pair or wheels having a common, fixed transverse axis of rotation. This helps prevent sideways drift of the trolley during motion over a floor, or loss of control of the trolley when traversing a slope. As a convenience aid, and to help avoid user-fatigue, the fixed wheel pair may be driven by an electric motor. This can be very useful for large trolleys which carry a significant load. In certain products available the drive is provided by a simple transaxle system to rear (or front) wheels of a trolley. At the other end of the base there are castor wheels fifted.

The use of wheels on axles always limits manoeuvrability as the trolley can only be rotated on these wheels if the centre of rotation is over the centre of the axle. It is very difficult to achieve this for an operator with rear fixed wheels as it requires considerable force to be applied to rotate the trolley and the moment arm to trolley handle is small. If the fixed drive axle is at the front of the trolley then it becomes a rear wheel steered device and this is easier to steer for the operator but can still be difficult in some situations.

The present invention seeks to provide a trolley which is motorised but which has improved manoeuvrability.

According to one aspect of the invention there is provided a trolley for supporting loads for transport over a floor surface, comprising a body portion provided with four spaced-apart wheels disposed at corners of a notional rectangle parallel to the floor surface, and which wheels are arranged to support the body portion on the floor surface, wherein a fifth wheel is disposed within said rectangle and is adapted to be driven so as to move, or assist movement of, the trolley over the floor surface.

The "fifth wheel" may be a single wheel or a (side-by-side) wheel pair.

Preferably there is only one driven wheel (or wheel pair) so that the single wheel can act as an axis for rotation of the trolley on the corner wheels for steering thereof.

The fifth wheel may be provided with bias means for urging the fifth wheel against the floor surface when the other corner wheels are in contact with the floor The biasing means may comprise a trailing arm and optional compression spring which acts between the trailing arm and a lower region of the body portion. More details are given in the following.

Two or more of the corner wheels are castor wheels and preferably all four of the corner wheels are castor wheels. Thus the trolley may be rotated about the driven wheel.

In one arrangement, a pair of the corner wheels at one end of the rectangle is arranged for rotation about a common, or parallel, transverse fixed axis of rotation. An opposite end region of the rectangle may be provided with a pair of the corner castor wheels.

The fifth wheel is preferably located between one third and two thirds of a fore-aft spacing between a front pair of the corner wheels and a rear pair of the corner wheels. The fifth wheel is preferably located between one third and two thirds of a lateral track separation between the opposite sides of the wheels. The fifth wheel is in preferred embodiments centrally, or substantially centrally, disposed between the four corner wheels.

The fifth wheel may be driven by a motor transmission with low or negative reverse efficiency so that the fifth wheel is braked or locked against rotation when not motor-driven. For example the fifth wheel may be driven by a sun-planet worm gear with an electric motor driving the sun/worm gear.

A trailing arm may be pivotably attached at one end region to a lower region of the trolley body portion and carries at an electric motor, transmission assembly and the fifth wheel. The trailing arm permits vertical displacement of the wheel with the pivoting trailing arm. The weight of the motor, transmission assembly and trailing arm urge the wheel onto the floor surface.

The trailing arm is preferably provided with spring means acting between a poi-tion of the arm and the lower region of the body portion, thereby to damp vertical motion of the trailing arm.

A rear end region of the body portion is typically provided with a push handle for manoeuvring the trolley. Again, the body portion is typically provided with generally upstanding superstructure which provides storage for items carried by the trolley.

The trolley may be provided with a user-operable switch for starting and stopping a motor which drives the fifth wheel. The switch is preferably a self-return switch which reverts to an off position in the absence of user-applied pressure. The switch may comprise a spring biased lever arm which can be displaced forward or backward with respect to a rest position.

Examples of trollies include without limitation a janitorial trolley or a hospital trolley or a hotel service trolley.

Following is a description by way of example only and with reference to the accompanying drawings of one mode for putting the invention into effect.

In the drawings:-Figure 1 is a rear three quarter perspective side view of a janitorial trolley in accordance with the invention.

Figure 2 is a perspective view of the underside of the same janitorial trolley.

Figure 3 is a plan underside view of the janitorial trolley.

Figure 4 is an underside perspective partially exploded view showing the fifth wheel assembly.

A janitorial trolley is shown generally as 10 in Figure 1. The trolley includes a generally oblong rectilinear base tray 11. Upstanding from an upper side of the tray is a superstructure provided by a metal frame work of upright members 12, horizontal members 13 and transverse members 14. The general construction is conventional and includes cupboard compartments and removable trays, some with lids and some without.

A rear end region of the trolley is provided with a horizontally extending U plan frame 15. A waste bin 20 is suspended from the frame 15 and is made of flexible porous plastics material. A distal end of this frame is formed by two parallel spaced apart transverse crossbars 16 and 17. The distal crossbar 17 forms a convenient graspable handle for pushing the trolley. A central region of the distal crossbar 17 carries a control panel 18. The control panel includes a push button 19 which is a stop. A rocker switch (not shown) is provided for actuating an electric drive motor (for which see Figures 2 etc.) The rocker switch may be a three position switch corresponding to forward drive, reverse drive and no drive. One side of the distal cross bar is provided with a speed control lever or twist grip (not shown) for proportionally controlling drive motor speed and therefore trolley velocity.

As will be seen in Figure 2, an underside of the tray 11 is provided with four castor wheels, one attached at each corner region of the tray. The castor wheels are configured each to be freely rotatable about a vertical axis. Again * this arrangement is conventional in the art. Each corner region of the tray is * also provided with transversely oriented bumper wheels 22 which help prevent scraping of walls, doorways or skirting boards by the trolley during travel. A central underside region of the tray is provided with a drive wheel assembly 23. The drive wheel assembly includes the drive wheel 24 itself and an electric motor 25 and a transmission box 26.

The transmission box contains a worm/ worm wheel gear arrangement (not visible) with the worm carried on the motor rotor and the worm wheel gear being carried on rotor 27, which serves as an axle to which is fixed the wheel 24. This arrangement is shown more clearly in Figure 3. The motor may be driven both ways to provide forward or reverse drive. There is however a mechanical disadvantage against back drive by rotating the worm, so the arrangement is essentially one way, with the worm acting as a break against passive movement of the drive wheel. Nevertheless there may optionally be brakes on one or more of the castor wheels, or on the drive wheel rotor.

The motor 25 and transmission box 26 are attached to a trailing arm 30 as shown in Figure 4. The trailing arm is formed of a U section pressed steel elongate member 30. A front end region of the member is formed with two aligned transverse bores 31 (only one visible in Figure 4). An underside of the tray is provided with a pressed steel mounting plate 32 which is provided with two depending brackets 33 and 34, which themselves have two transversely aligned bores 35. A pivot pin (not shown) is accommodated in the bores (31,35) and mounts the front end region of the trailing arm to the depending flanges 33 and 34, so as to permit pivoting of the trailing arm in a vertical arc.

A distal region of the trailing arm (hidden from view in Figure 4) is provided with a vertically disposed coil spring which is attached at one end to the trailing arm and at upper end to the plate 32. The arrangement is such that the fifth wheel is located centrally between the four corner castor wheels. The trailing arm pivot bracket 33,34 is thus offset towards a front region of the tray.

When the trolley is placed on a floor surface, the weight of the motor and transmission box help urge the fifth wheel into intimate contact with the floor surface, so as to provide drive traction. The coil spring also serves to urge the trailing arm downwards and also damps upward movement of the arm in response to uneven surfaces during travel of the trolley. An upper surface of the tray (not shown) is provided with a battery compartment for powering the electric motor 25. The battery (not shown) is located above, and supported by, the mounting plate 32. The battery is electrically connected to the control box 18 via electric cables (not shown). When the user desires to activate the electric motor for forward motion of the trolley, the button 19 on the control panel is pressed and the motor 25 is activated. As will be seen from the figures, the disc wheel 24 is aligned to drive the trolley in a forward direction with its rotor 27 fixed in a transverse direction. The sun and planet worm gear transmission arrangement provides a breaking effect when the push button is released and the motor ceases to be powered. The drive wheel thus acts as a brake to slow the trolley when the drive motor is unpowered, preventing unwanted movement of the trolley.

As compared to prior art driven trolleys in which a pair of fixed rear wheels may be driven about a common axle, the present trolley can be easily steered by rotation about the central axis of rotation defined by the contact surface of the fifth wheel. By contrast prior art trolleys must be steered by rotation about the fixed (front or rear) wheel pairs, which requires significant yawing from side to side of the castor wheel end of the trolley. For a massive trolley this can be a significant effort. In addition, this yawing action can be particularly inconvenient when operating the trolley in narrow confines such as hotel corridors or through doorways. Thus the present invention provides a janitorial trolley (and trolleys in general) which are driven yet retain excellent manoeuvrability.

In summary, the present invention relates to the field of trolleys for carrying loads over a floor surface (including ground surface). Examples include janitorial trolleys, laundry trolleys, hospital trolleys and hotel service trolleys.

The invention seeks to provide a motorised trolley having improved manoeuvrability. The invention provides a trolley for supporting loads for transport over a floor surface, comprising a body portion provided with four spaced-apart wheels disposed at corners of a notional rectangle parallel to the floor surface, and which wheels are arranged to support the body portion on the floor surface, wherein a fifth wheel is disposed within said rectangle and is adapted to be driven so as to move, or assist movement of, the trolley over the floor surface. The fifth wheel may be provided with bias means for urging the fifth wheel against the floor surface when the other corner wheels are in contact with the floor. Preferably all four of the corner wheels are castor wheels.

Claims

Claims 1. A trolley for supporting loads for transport over a floor surface, comprising a body portion provided with four spaced-apart wheels disposed at corners of a notional rectangle parallel to the floor surface, and which wheels are arranged to support the body portion on the floor surface, wherein a fifth wheel is disposed within said rectangle and is adapted to be driven so as to move, or assist movement of, the trolley over the floor surface.
2. A trolley as claimed in claim 1 wherein the fifth wheel is provided with bias means for urging the fifth wheel against the floor surface when the other corner wheels are in contact with the floor.
3. A trolley as claimed in claim 2 wherein the biasing means comprises a trailing arm and optional compression spring which acts between the trailing arm and a lower region of the body portion.
4. A trolley as claimed in any of the preceding claims wherein two or more of the corner wheels are castor wheels.
5. A trolley as claimed in any of the preceding claims wherein all four of the corner wheels are castor wheels.
6. A trolley as claimed in any of claims ito 4 wherein a pair of the corner wheels at one end of the rectangle are arranged for rotation about a common, or parallel, transverse fixed axis of rotation.
7. A trolley as claimed in claim 6 wherein an opposite end region of the rectangle is provided with a pair of the corner wheels which are castor wheels.
8. A trolley as claimed in any of the preceding claims wherein the fifth wheel is located between one third and two thirds of a fore-aft spacing between a front pair of the corner wheels and a rear pair of the corner wheels.
9. A trolley as claimed in any of the preceding claims wherein the fifth wheel is located between one third and two thirds of a lateral track separation between the opposite sides of the wheels.
10. A trolley as claimed in any of the preceding claims wherein the fifth wheel is centrally, or substantially centrally, disposed between the four corner wheels.
11. A trolley as claimed in any of the preceding claims wherein the fifth wheel is driven by a motor transmission with low or negative reverse efficiency so that the fifth wheel is braked or locked when not motor-driven.
12. A trolley as claimed in any of the preceding claims wherein the fifth wheel is driven via a worm/worm wheel arrangement with an electric motor driving the worm.
13. A trolley as claimed in any of the preceding claims wherein a trailing arm is pivotably attached at one end region to a lower region of the trolley body portion and carries at an electric motor, transmission assembly and the fifth wheel, the trailing arm permitting vertical displacement of the wheel with the pivoting trailing arm, and wherein the weight of the motor, transmission assembly and trailing arm urge the wheel onto the floor surface.
14. A trolley as claimed in claim 13 wherein the trailing arm is provided with spring means acting between a portion of the arm and the lower region of the body portion, thereby to damp vertical motion of the trailing arm.
15. A trolley as claimed in any of the preceding claims wherein a rear end region of the body portion is provided with a push handle for manoeuvring the trolley. [0
16. A trolley as claimed in any of the preceding claims wherein the body portion is provided with generally upstanding superstructure which provides storage for items carried by the trolley.
17. A trolley as claimed in claim any of the preceding claims wherein the trolley is provided with a user-operable switch for starting and stopping a motor which drives the fifth wheel.
18. A trolley as claimed in claim 17 wherein the switch is a self-return switch which reverts to an off position in the absence of user-applied pressure.
19. A trolley substantially as hereinbefore described with reference to the figures of the drawings.