EP1995393A2

EP1995393A2 - A work platform

Info

Publication number: EP1995393A2
Application number: EP08009426A
Authority: EP
Inventors: Terence Nolan; Thomas O`Neill; Dominic Martin
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-05-23
Filing date: 2008-05-22
Publication date: 2008-11-26

Abstract

A work platform unit (1) comprising, a bottom frame (2) carrying wheels, side supports (12,13) that end at the bottom frame (2), a platform (20) carried by the side supports (12,13), the platform (20) being height adjustable, a safety rail (21) for the platform (20), a drive (10,90,58) to allow the work platform unit (1) to be driven by a user, wherein the drive is a manual drive, a steering mechanism (67,69) to enable the user to control the direction the work platform unit (1) is driven and wherein the work platform unit (1) is foldable.

Description

Introduction

The invention relates to a movable working platform which can be used to perform a range of tasks at an elevated height such as various construction, repair, decoration, cleaning, warehousing or library tasks. Some platforms are drivable platforms and have an on-board driving system that allows a user to move the platform while in position on it, other platforms are not drivable and require the user to dismount the platform in order to move it.
The on board driving systems of drivable platforms include components such as batteries and electrics. The electric and battery components pose a high risk of sparking and therefore make the platforms unsuitable for use in areas where there is a high risk of explosion e.g. in areas containing flammable gasses.
The electric and battery components greatly increase the weight of the drivable platform, making the platform unsuitable for use in weight restricted areas. Also, the increased weight of such platforms makes them difficult to transport. These heavy drivable platforms require a transporting vehicle or else must be disassembled and re-assembled, when being moved from one site to the next. There are numerous parts which can be easily lost during these operations. In addition, if the unit is assembled by non-skilled workers the assembly may not be completed correctly leading to major safety concerns.
Another safety concern is that such platforms cannot safely be operated at a range of heights. Such units are also generally large and unwieldy which presents transportation problems and difficulties in moving through some openings such as a domestic doorway. Further, often in such systems the braking system is not optimum.
This invention is directed towards providing a work platform which will address at least some of these problems.

Statement of Invention

According to the invention there is provided a work platform unit comprising:-

a bottom frame carrying wheels;
side supports that end at the bottom frame;
a platform carried by the side supports, the platform being height adjustable;
a safety rail for the platform;
a drive to allow the work platform unit to be driven by a user, wherein the drive is a manual drive;
a steering mechanism to enable the user to control the direction the work platform unit is driven;
and wherein the work platform unit is foldable.

As the drivable, steerable platform unit is foldable this enables the work platform unit to be transported without having to be disassembled. The platform may be manually driven using the manual drive, this eliminates the need for batteries and electric components and permits the platform unit to be used in areas where there is a high risk of explosion. The absence of batteries and electric components makes the platform unit lighter thereby allowing it to be used in weight restricted areas.
In one embodiment the platform is height adjustably mounted to the side support.
In one case the safety rail is attached to the platform so that the safety rail moves in conjunction with the platform during height adjustment.
In one embodiment height adjustment means is provided between the platform and side support. The adjustment means may comprise a plurality of support locators spaced-apart on the support for engagement with corresponding platform locators.
In one case there are two side supports, one of which is pivotally movable relative to the base and/or the platform to adjust in position dependent on the position of the platform. The movable support may provide an access ladder to the work platform.
In one embodiment the manual drive is operable by a user located on the platform of the work platform unit.
In one embodiment the manual drive is operated by a pedal.
In one embodiment the manual drive is operated by a pedal, wherein pedalling the pedal may pull a chain around a sprocket which in turn rotates a drive wheel which drives the work platform unit.
In one embodiment the manual drive is attached to the work platform so that it moves with the platform.
In one embodiment the manual drive further comprises a free wheel mechanism between the sprocket and the drive wheel.
In one embodiment the unit comprises a brake.
In one case the bottom frame is extendable. The bottom frame may comprise at least one telescopic member. The bottom frame may comprise two telescopic members.
In one case the safety rail is foldable.

Brief Description of the Drawings

The invention will be more clearly understood from the following description thereof given by way of example only in which:-

Fig. 1 is a perspective view of a work platform unit of the invention;
Figs. 1A to 1C are enlarged views illustrating pivotal movement of the side support relative to a bottom frame;
Fig. 2 is a top plan view of the unit of Fig. 1;
Figs. 3 and 4 are front elevational views of the unit with the platform at different heights;
Fig. 5 is a detailed view of a drive unit forming part of the platform;
Fig. 5A is another view of the drive unit;
Fig. 5B is an enlarged cross sectional view of a lower movement sleeve part of the drive unit;
Fig. 5C is a cross sectional view on the line A-A in Fig. 5B;
Fig. 5D is a perspective view of a rod bushing part of the movement sleeve of Figs. 5B and 5C;
Figs. 5E and 5F are diagrams illustrating movement of the rod bushing;
Fig. 5G is a diagram illustrating a detail of the chain and sprocket drive;
Fig. 6 is an enlarged, partially cross sectional view of part of the drive train;
Fig. 7 is a perspective view of an upper part of the platform unit;
Fig.7A and 7B are side views illustrating an alternative lug arrangement of the unit;
Figs. 8 and 9 are perspective views illustrating a braking system of the unit;
Fig. 10 is a perspective view of the work platform unit in a collapsed folded configuration;
Fig. 11 is an underneath plan view of the unit in the folded configuration of Fig. 10;
Figs. 12 to 16 are diagrams illustrating the work platform unit of the invention with the work platform at various working heights;
Fig. 17 is an underneath plan view of the unit in the position of Fig. 12; and
Figs. 18(a) to 18(g) are diagrams illustrating the folding of the unit.

Detailed Description

Referring to the drawings a work platform unit 1 according to the invention comprises a bottom frame 2 carrying wheels. There are a rear pair of wheels 3, 4 both of which has a brake 5 which is operated in a manner which will be described below. There are also a pair of smaller front wheels or castors 6, 7 which are mounted on adjustable extension arms 8, 9 which can be telescoped as illustrated to extend the footprint of the unit and thereby improve stability, in use. There is also a separate front wheel 10 which is steerable and drivable as will be described in more detail below.
The work platform unit 1 also comprises a front side support 12 and a rear side support 13 which both extend from the bottom frame 2. A working platform 20 is carried horizontally by the front and rear supports 12, 13. The platform 20 is surrounded on all sides by safety rails 21 which are carried by the platform 20 so that the safety rails are retained in position as the platform 20 is raised or lowered. The safety rail system includes a closable access gate 22. The rear support 13 comprises a pair of side members 25, 26 with a series of cross members 27 extending therebetween to define an on-board ladder for user access to and from the platform 20. It will be noted that the rear support 13 is pivotally mounted at its low end by sleeves 28 to a bottom frame member 29 and also pivotally mounted at its upper end by sleeves 30 to a platform member 31 to facilitate movement of the rear support 13 as the platform is raised and lowered.
Referring in particular to Figs. 1A, 1B and 1C to facilitate folding, the front side supports 12 have rearwardly extending arms 12B which are pivotally attached by a pivot 12A to the base 2. To lock the side supports 12 in the upright position, the ends of the supports 12 have a spigot 12C which engages in a socket 12D on the base 2. A locking pin 12E is used to lock the upright 12 to the base 2.
The front support 12 comprises a pair of uprights 40 which are interconnected at their upper end by a connecting cross piece 41. The uprights 40 have a plurality of spaced-apart location projections 45, the projections 45 from one upright being aligned with and facing the projections from the opposite upright. The projections 45 define fixed discrete heights at which the platform 20 can be set. As will be particularly apparent from Fig. 7 the platform 20 has a pair of depending lugs 50, each with a semi-circular cut-out 51 at each end for engagement, as illustrated, with pairs of adjacent projections 45 on each upright 40. A range of heights to which the platform 20 can be set is illustrated particularly in Figs. 1, 3, 4 and 12 to 17.
Alternatively, the depending lugs may take the form shown in Figures 7A and 7B. The depending lugs 700 as shown in Figure 7A and Figure 7B comprise a first, hooked, end 702 and a second, stepped, end 704. The first, hooked, end 702 further comprises a locking mechanism 708. In use the first, hooked, end 702 is hooked around one of the projections 45. The second stepped end 704 engages another projection 45, as shown in Figures 7A and 7B. The depending lug 700 is locked in place by locking the locking mechanism 708, as shown in Figure 7B.
Referring in particular to Figs. 5 to 9 the steerable and drivable wheel 10 is operated as follows. In use, pressing a pedal 86 causes a pedal ladder 90 to move upwards.
Upper and lower movement sleeves 66, 64 are attached to the pedal ladder 90, and as the ladder 90 moves upward the sleeves 66, 64 also move upward. The sleeves 64, 66 are on a steering axle 67.
In more detail the lower movement sleeve 64 operates as follows. An outer housing of the sleeve 64 contains a top and bottom bearings 55, 56 (Fig. 5B). Axle 67 has an elongate vertical opening 57B large enough to allow a rod fixing guide 57 to pass through. The rod fixing guide 57 is attached to a chain rod 58 through a rod bushing 59 using two screws 59a. The rod bushing 59 keeps the chain rod 58 concentric with the steering axle 67. As the lower movement sleeve 64 moves upwards, the bottom bearing 56 contacts the rod fixing guide 57 and moves it up. The rod fixing guide 57 in turn moves the chain rod 58 up and this causes the wheel 82 to rotate. The steering axle 67 can rotate within the lower movement sleeve 64, whilst the pedal ladder 90 remains fixed.
The steering axle 67 has a telescoping top section 68 and a steering handle 69. The wheel 10 is attached to the lower end of the steering axle 67. When in motion, if the steering handle 69 is rotated the drive wheel 10 is rotated and changes the direction of rotation. By turning the wheel through 180 degrees a reverse motion is achieved.
Concentric with the steering axle 67 is the chain rod 58, the upper end of which is connected to the rod fixing guide 57, the lower end of which is attached to a chain 83. The other end of the chain 83 is attached to a spring 80. The chain 83 is trained around a sprocket 82 and the other end of the chain is in turn attached to a housing 60 by means of the spring 80 (Fig. 5G). Moving the lower sleeve 64 upwards causes the chain rod 58 to move upwards which pulls the chain 83 around the sprocket 82 which in turn rotates the drive wheel 10. When the force is removed from the lower sleeve 64, the spring pulls the chain 83 back (there is a one way clutch or free wheel mechanism between the sprocket and the wheel) which pulls the chain rod 58 downwards which in turn moves the lower sleeve 64 downwards and returns the pedal 86, ready for the next cycle.
The drive ladder 90 is attached at 91 to the lower sleeve 64. The ladder 90 also has the upper sleeve 66 at its upper end. The drive ladder 90 has short horizontal cylindrical projections 95 spaced equally along its length for engaging with an arm 86A of the pedal 86. The projections 95 on the ladder 90 are at the same spacing as the projections 45 on the front frame 12 so that the pedal 86 can engage at each of the different heights of the platform 12. Thus the pedal 86 engages with the projections 95 (Fig. 6). Moving the pedal 86 downwards rotates it about the pivot and causes the drive ladder 90 to slide upwards along the steering axle 67 and thereby rotates the drive wheel.
The bushing 59 is attached to the top of the drive rod 58. The bushing 59 keeps the rod 58 concentric with the steering axle 67. Extending through a slot 57A in the bushing 59 is a key 57 which projects through a long slot 57B in the steering axle 67. The slot 57B is sufficiently long to allow the key 57 to move a distance greater than the stroke of each pedal 86 movement. The lower sleeve 64 has an internal diameter sufficient to provide clearance between the outer face of the key 57 and its inner surface. The top and bottom bearings 55, 56 allow the steering axle 67 to rotate within the housing and also contact the key 57 and move it up along the shaft if the sleeve 64 is moved upwards. This provides a permanent connection between the pedal ladder 90 and the rod 58 while also allowing the steering axle 67 to rotate.
To raise the drive wheel off the ground a toggle clamp 85 is attached to a stud 85A on the housing 60 and locked. This raises the housing 60 by compressing a spring 61. This facilitates moving the platform manually.
Referring to Fig. 7 the steering handle 69 can be adjusted to a number of positions which correspond to the different heights of the platform. The handle 69 is adjusted by removing the pin from receiving hole 69B and telescoping the top section 68 into the steering axle/shaft 67 to give the correct height and then reinserting the pin 69A.
Referring especially to Figs. 8 and 9 a brake actuator 105 [Fig. 4] is connected by means of a cable 5B to the brake rod 5 through a lever 5A. Moving the handle on the brake actuator 105 pulls the cable 5B which is attached to one end of the lever 5A, which pivots and presses the ends of brake rod 5 against the outer circumference of the wheels 3 and 4, providing a braking mechanism.
Folding is accomplished as follows. The handrail 21A is first raised slightly and 21B is pivoted towards the front frame 12 sufficient to allow the handrail 21A to pivot downwards to rest parallel and in contact with cross member 21C. Arm 21B is then pivoted to be parallel to cross member 21C and on top of handrail 21A. By pivoting the entire assembly 21 about a lower pivot 21D, the assembly 21 is lifted up sufficient to clear the sockets 21E. The assembly 21 is then pivoted to rest parallel and in contact with cross member 21C. The assembly 21 can then be pivoted about 21D until the handrails are horizontal and as shown. Referring especially to Figs. 1A, 1B and 1C releasing the locking pins 12E allows the front frame 12 to be pivoted into a horizontal position about the pivot 12A. The unit is now in the folded configuration illustrated in Fig. 10.
The platform unit of the invention is a foldable, height adjustable, one piece drivable work platform. Amongst the advantages of the invention are that the unit can be one piece, light weight (typically can be readily lifted by two people), compact - can fit in a transporter van. Importantly, for safety, the handrails move with the platform. When assembled, the unit can fit through a doorway. A telescoping steering shaft allows the steering handle to be lowered part of the way down as the platform is lowered. The unit also has an improved braking system.
In addition, the unit has an improved means of operating the drive which allows the pedal to be operated at a lower platform level.
The invention is not limited to the embodiments hereinbefore described which may be varied in detail.

Claims

A work platform unit comprising:-
a bottom frame carrying wheels;

side supports that end at the bottom frame;

a platform carried by the side supports, the platform being height adjustable;

a safety rail for the platform;

a drive to allow the work platform unit to be driven by a user, wherein the drive is a manual drive;

a steering mechanism to enable the user to control the direction the work platform unit is driven;

and wherein the work platform unit is foldable.
A work platform unit as claimed in claim 1, wherein the platform is height adjustably mounted to the side support.
A work platform unit as claimed in claim 1 or 2, wherein the safety rail is attached to the platform so that the safety rail moves in conjunction with the platform during height adjustment.
A work platform unit as claimed in any preceding claim, wherein height adjustment means is provided between the platform and side support.
A work platform unit as claimed in claim 4, wherein the height adjustment means comprises a plurality of support locators spaced-apart on the support for engagement with corresponding platform locators.
A work platform unit as claimed in any preceding claim, wherein there are two side supports, one of which is pivotally movable relative to the base and/or the platform to adjust in position dependent on the position of the platform.
A work platform unit as claimed in claim 6, wherein the movable support provides an access ladder to the work platform.
A work platform unit as claimed in any preceding claim, wherein the manual drive is operable by a user located on the platform of the work platform.
A work platform unit as claimed in any preceding claim, wherein the manual drive is attached to the work platform so that it moves with the platform.
A work platform unit as claimed in any preceding claim, wherein the manual drive is operated by a pedal, wherein pedalling the pedal pulls a chain around a sprocket which in turn rotates a drive wheel which drives the work platform unit.
A work platform unit as claimed in claim 10, wherein the manual drive further comprises a free wheel mechanism located between the sprocket and the drive wheel.
A work platform unit as claimed in any preceding claim, wherein the bottom frame is extendable.
A work platform unit as claimed in any preceding claim, wherein the bottom frame comprises at least one telescopic member.
A work platform unit as claimed in any preceding claim, wherein the safety rail is foldable.
A work platform unit as claimed in any preceding claim, wherein the work platform unit comprises a brake.