GB2352759A

GB2352759A - Variable height platform

Info

Publication number: GB2352759A
Application number: GB9917859A
Authority: GB
Inventors: Michael Anthony Norman
Original assignee: HANCROFT
Current assignee: HANCROFT
Priority date: 1999-07-29
Filing date: 1999-07-29
Publication date: 2001-02-07
Anticipated expiration: 2019-07-29
Also published as: GB9917859D0; GB2352759B

Abstract

A variable height platform comprising a working platform (2) having a flat support surface suitable for a user to stand on and having two ends, each of which has a pair of substantially parallel brackets (8) attached thereto, and a pair of end units (1) each having a base element (4) and a support element (3) extending upwardly therefrom, the support element having a plurality of slots (5) therethrough arranged for cooperation with the brackets so that when the end units are brought into contact with the working platform each bracket passes through two slots so that the working platform is supported by the end units with the support surface substantially horizontal, and further comprising locking means releasably securing the brackets within the slots.

Description

2352759 Variable Height Platform This invention relates to a variable

height platform and in particular to a portable variable height platform.

In many situations, particularly in the fields of building, painting and decorating, tree and hedge clipping, and similar activities it is desirable or even essential to provide a free-standing working platform for a worker to stand on at a suitable height relative to the Mork to be done.

A number of ways of providing such a working platform are known. The commonest is the use of rigid trestles with planks or another suitable flat platform surface resting on them. However, this arrangement suffers from the disadvantage that the trestles are bulky to store when not in use and that the height of the platform is fixed.

Other arrangements which provide a variable height for the working platforrn are known. One is to assemble a free-standing tower from a number of components and then place planks on, or secure floor members with integral brackets to, the tower. The height of the work surface is varied by building the tower to an appropriate height.

This system provides a safe and secure working platform but is generally complex and slow to erect and dismantle and heavy and bulky to move and store when not in use. Finally, such systems are costly. Although they are commonly used by professional builders and decorators they are too expensive for many small businesses to afford and are prohibitively expensive for virtually all amateur/DIY users.

Another arrangement often used is to balance a plank across the rungs of two step ladders. Although this does provide a variable height working platform and is cheap and simple such an arrangement is unstable and dangerous to use.

This invention was intended to overcome the above disadvantages, at least in part.

This invention provides a variable height platform comprising a working platform having a flat support surface suitable for a user to stand on and having two ends, each of which has a pair of substantially parallel brackets attached thereto, and a pair of end units each having a base element and a support element extending upwardly therefrom, the support element having a plurality of slots therethrough arranged for 2 cooperation with the brackets so that when the end units are brought into contact with the working platform each bracket passes through two slots so that the working platform is supported by the end units with the support surface substantially horizontal, and further comprising locking means releasably securing the brackets within the slots.

A first adjustable trestle according to the invention will now described with reference to Figures I to 4.

As shown in Figure I the adjustable height platform is formed by three main elements, two end units 1 and a working platform 2.

Each end unit 1 is formed by a pair of spaced apart parallel vertical support sections 3 secured to a horizontal base section 4. Each of the horizontal and vertical sections 3 and 4 is formed by a U section steel channel, the spacing of the side walls of the of U section channel of the base section 4 being slightly larger than that of the vertical sections 3 so the vertical sections 3 sit within the base section 4 so that the structure can be securely held together. A plurality of slots 5, in this case four slots 5, pass through each side wall of each of the vertical support sections 3. The slots 5 are spaced equidistantly along the vertical support sections 3. The corresponding slots 5 in the opposed side sections of each vertical support section 3 and in each of the vertical support sections 3 are arranged at a common height.

The working platform 2 is formed from a pair of longitudinal support elements 6, again formed by substantially U-sectioned channel members, secured to the bottom surface of a rectangular flat working platform element 7 to be spaced apart in parallel and to run parallel to the long sides of the rectangular working platform element 7.

At each end of each of the support elements 6 a projecting bracket 8 is integrally formed by the central section only and not the side sections of each U-section support element 6 extending beyond the ends of the working platform element 7. Preferably, the side sections of the U- section support elements 6 extend to and stop at the ends of the working platform element 7.

The slots 5 and projecting brackets 8 are arranged to allow the projecting brackets 8 to fit through the slots 5 so that when an end unit I is in contact with the end of the working platform element 7 of the working platform 2 each of the projecting brackets 3 8 passes through both of the opposed slots 5 in the opposed side sections of a vertical support section 3.

It will be understood that in order to allow the adjustable height platform to be easily assembled and disassembled and to provide a safe and secure working platforrn the projecting brackets 8 should be slightly smaller in width and thickness than the slots 5.

In order to ensure that the brackets 8 cannot be accidentally removed from the slots 5 when the platform is being used, a locking mechanism 9 is provided for each projecting bracket 8.

The locking mechanism 9 comprises holes 10 and 11 formed in the projecting brackets 8 and vertical sections 3 respectively. Each vertical support section 3 has one such hole 11 in the surface of the channel section forming the base of the U-section associated with each pair of opposed slots 5.

The holes 10 and 11 are arranged so that when a projecting bracket 8 is fully inserted through a pair of opposed slots 5 so that the end unit I and working platform 2 are correctly located the holes 10 and 11 are in line.

Adjacent each projecting bracket 8 a spring member 12 is provided having a first end 12a attached to a support element 6 and a pin 13 projecting from a second free end 12b remote from the first end 12a.

The spring member 12 is arranged so that when it is not being restrained it moves to a position where the pin 13 passes through the hole 10. An intermediate section 12c of the screen member 12 intermediate the first and second ends 12a and 12b is formed into a hollow convex shape having a apex projecting away from the support element 6 and projecting bracket 8. This convex intermediate section l2c. forms a simple grip allowing a user to easily pull on the spring section 12 to remove the pin 13 from the hole 10 as required.

In order to assemble the adjustable height platform the working platform 2 is offered up to one of the end units I so that the ends of the projecting brackets 8 each pass through one of the slots 5 in one of the vertical support members 3 to give the working platform element 7 a desired height. The spring members 12 adjacent to the two engaged projecting brackets 8 must then be pulled away from the projecting brackets 8 to move the pins 13 clear of the respective holes 10. Then, the working platform 2 can be urged 4 closer towards the end unit I so that the projecting brackets 8 pass through the second slot 5 opposed to the first slot 5 it has already passed through. Finally, once the working platform 2 is correctly positioned adjacent the end unit 1 so that holes 10 and 11 are aligned the spring elements 12 can be released so that each pin 13 passes through holes 10 and I I to securely hold the working platform 2 and end unit I together. The process is then repeated for the other end unit 1. Of course, if two or more people are available there is no reason why both end units I should not be secured to the working platform 2 simultaneously.

This procedure is reversed to dismantle the adjustable height platform.

It will be understood that in order to attach or detach one of the end units I from the working platform 2 it is necessary to- simultaneously disengage both of the pins 13 locking that end unit I to the working platform 2 by simultaneously urging both of the corresponding spring elements 12 away from their respective projecting brackets 8. This provides security against accidental detachment of the end units I from the working platform unit 2 because even if one of the pins 13 is inadvertently moved out of place by some accidental contact with the mechanism the adjustable trestle will remain intact. Once the accidental contact with the mechanism ends the pin 13 will automatically be urged back through the holes 10 and I I by the spring element 12. Thus, accidental dismantling of the adjustable trestle can only occur in the unlikely event of simultaneous accidental contact with both of the spring elements 12 or pins 13 at one end of the working platform unit 2 simultaneously.. In order to allow a single user to assemble and disassemble the adjustable trestle the spacing of the structural support elements 6 must be such that a person can easily reach both spring elements 12 simultaneously and it is preferred that the size of the working platform element 7 be such that a person can easily reach around. both sides of the working platform element 7 from above to reach both of the spring elements simultaneously.

This structure provides a simple, lightweight and inexpensive adjustable height platform having a working platform height that can be easily varied by placing the projecting brackets 8 through appropriate opposed pairs of the slots 5. The inventive adjustable height platform is lightweight and compact when disassembled allowing easy transportation and storage.

The inventive variable height platform is sufficiently lightweight to allow a single person to lift and move the platform as required as work progresses. However, in view of the bulky nature of the assembled platform it will normally only be convenient to move the assembled platform for short distances. For longer moves it will normally be simpler and more convenient to disassemble the platform, transport it to the new location and then reassemble it.

It is preferred for the entire structure except the spring elements 12 and pin 13 to be formed of aluminum with the parts of each end unit 1 and the working platform unit 2 being welded together. In view of the required spring action the use of steel for the spring element 12 and pin 13 will normally be preferred.

This selection of materials is purely exemplary and suitable industrial plastics or steel could be used instead. Further, the"use of the same material throughout is not essential, different parts of the adjustable height platform structure could be formed from different materials as desired. In particular, where the support elements 6 are formed of steel it will normally be desirable to form the working platform element 7 from wood, plastics or aluminum in order to avoid excessive weight. The adjustable platform may of course by painted or galvanised as required.

Although the use of welding is preferred, other fabrication methods could be used.

In order to finther ensure against accidental unlocking, the spring elements could be located between the support elements 6, moving towards one another to release the locking pins 13.

Referring to Figures 5 and 6 an alternative arrangement for the end units I is shown.

In this alternative, each end unit 1 is formed by a pair of parallel vertical spaced apart square section tubes 13 secured to a bottom member 14 formed by a rectangular section tube. In this alternative construction the vertical support members 13 pass through square holes 15 cut in the upper face of the bottom member 14.

In this example there are six vertically spaced apart sets of slots so that the adjustable trestle can be assembled with the working platform 2 at six different heights.

6 It will be understood that the number of sets of slots and the resulting number of possible working platform heights can be selected as desired.

A further alternative construction for the end units 2 is shown in Figure 7 which shows a horizontal cross section through a vertical support member 16.

In this alternative construction the vertical support member 16 comprises a first section 16a formed by a square section tube and a second section l6b formed by a shallow U section channel. The two sections 16a and l6b are welded together. Slots 5 are formed in the opposed parallel sides of the U-section channel section l6b.

There is of course no requirement for the vertical and horizontal members of the end units 2 to have similar cross sections, although this may be convenient in practice in order to allow the same manufacturing processes to be used to produce all parts of the end unit 1.

Other shapes of support members could be used, the examples described are convenient to use, but are examples only. U-section channel support members could be combined with a tubular bottom member or vice versa. Alternatively other crosssectional shapes of channel members could be used, for example circular or triangular cross-section tubes.

An alternative locking structure is shown in Figures 8a and 8b.

In this alternative arrangement each of the support elements 6 has a locking member 17 pivotally mounted near to each of its ends.

Each locking member 17 is formed by an elongate strip pivotally connected at a first end to a support element 6 and having a locking pin 18 projecting at a second end remote from the first end.

The locking pins 18 fit into holes 19 in the vertical support members 3. The holes 19 are located below the corresponding slots 5 into which the projecting brackets 8 are fitted so that the locking member 17 extends diagonally across between the vertical support member 3 and the support element 6.

In order to bias the locking pins 18 into the holes 19 to prevent accidental release of the working platform 2 from the end unit I a tension spring 20, such as a coil spring for example, is attached between the two locking members 17 at each end of the working platform 2 to urge the locking members 17 towards one another. The locking members 7 17 are arranged to pass around the outside of the vertical support members 3 of the end unit I so that the pins 18 pass into the holes 19 from the outside. As a result, the urging together of the two locking members 17 by the tension spring 20 urges their respective locking pins 18 into the holes 19.

Each locking member 17 is bent through a double bend at a point intermediate its first and second ends and close to the position where the spring 20 is attached to the locking member 17 to provide a clearance between the support element 6 and the opposed surface of the locking member 17. This clearance allows the user to easily get hold of the locking members 17 when they are in a position parallel to the support element 6 and pull them apart to remove the locking pins 18 from the holes 19 and allow the working platform 2 to be attached to or detached from the end unit 1.

This alternative arrangement allows the locking member 17 to act as a diagonal brace between the end unit 1 and working platform 2 and so increase the rigidity of the adjustable height platform structure.

In order to assemble an adjustable height platform using this alternative embodiment the locking members 17 at one end of the working platform 2 should be swung down away from the working platform 7 and the projecting brackets 8 then inserted into the slots 5 of the end unit I at the desired height. The locking member 17 should then be swung upwards and urged apart to allow the locking pins 18 to clear the sides of the end unit 1 until the locking pins 18 overlie and can be inserted into the holes 19.

In this alternative locking arrangement the spring biassing of the locking members 17 towards one another biases the locking pins 18 into the holes 19 and so the working platform 2 and end units I are unlikely to become accidentally disconnected as explained in more detail with respect to the first arrangement.

Although this alternative arrangement is more complex it will provide a more rigid adjustable height platform structure. Further, this alternative arrangement allows the steps of assembly of the end unit 1 and working platform 2 together to be carried out separately from the step of locking them together. This will make assembly of the adjustable height platform simpler and less demanding of the users dexterity. However, this alternative arrangement is less fail-safe because it is possible for a user to attach the 8 working platform 2 to the end units I and not lock it in place. The advantage of the first arrangement is that this cannot be done because assembly of the end units I and working platform 2 into their correct positions will automatically cause the locking mechanism to function.

The described locking mechanisms could of course be mounted on the end units 1 instead of the working platform 2. However, it will normally be more convenient for the user if they are mounted on the working platform 2.

The described springs could be replaced by other forms of resilient means if desired.

The use of only a single locking pin to secure the working platform 2 to each end unit I would be possible, but the use of two is preferred to increase the rigidity of the platform structure and make accidental unlocking more unlikely.

In the above examples, the projecting brackets 8 are simple rectangular projections passing through two equally sized slots. An alternative bracket arrangement is shown in Figure 9.

In the alternative bracket arrangement each bracket 21 instead of being substantially rectangular, has a flat horizontal upper surface 2 1 a and a curved lower surface 2 1 b defining a partial circular arc so that the bracket 21 narrows away from the support element 6.

At the end of the bracket 21 further from the support element 6 the bracket 21 has an upwardly projecting cam element 21c.

The vertical support section 3 has two different sized slots 5a and 5b arranged in parallel opposed surfaces of each vertical support section 3 so the large slots 5a and small slots 5b are arranged in pairs in line with their upper ends at the same position along the vertical support section 3.

The slots 5 a and 5b and the bracket 21 are sized so that each bracket 21 can pass through a large slot 5a and then through a small slot 5b. The vertical support section 3 must be held slightly off perpendicular to the support elements 6 as the support section 3 comes into contact with the end of the support elements 6 in order to allow the cam 21 c to pass through the slot 5b. The vertical support section 3 can then be rotated slightly to be 9 perpendicular to the support element 6 so that the cam 21c projects beyond the end of the slot 5b. A pivoting locking member 17 bearing pins 18 cooperating with holes 19 in the vertical support element 3 is employed as in the embodirnent shown in Figure 8 to lock the working platform 2 to the support unit 1.

This embodiment allows the stability of the adjustable trestle structure to be increased.

Although the use of slots 5a and 5b having different sizes is shown in Figure 9 it would be possible for the slots to be all made the same size so that the end units 1 are symmetrical.

In the described embodiment the end units 1 are formed by two separate vertical supports. It would be possible to have more such vertical supports or to have only a single vertical support. Where two or more separate supports are used, they can be interlinked to increase their rigidity if necessary.

The examples described above are exemplary only and it will be realised by the person skilled in the art that numerous substitutions of elements with mechanical equivalents would be possible. In particular, the various forms of end units, locking mechanisms and brackets described above could be differently combined. All of the alternative arrangements for different parts of the adjustable trestle described above are compatible with one another and can be combined together as desired.

Claims

Claims:

1. A variable height platform comprising a working platform having a flat support surface suitable for a user to stand on and having two ends, each of which has a pair of substantially parallel brackets attached thereto, and a pair of end units each having a base element and a support element extending upwardly therefrom, the support element having a plurality of slots therethrough arranged for cooperation with the brackets so that when the end units are brought into contact with the working platform each bracket passes through two slots so that the working platform is supported by the end units with the support surface substantially horizontal, and further comprising locking means releasably securing the brackets within the slots.

2. A platform as claimed in claim 1, in which the locking means includes a pin moveable between a first, locking, position in which the pin passes into an aperture in the support element to secure a bracket with the slots and a second, release, position in which it does not and a biassing means biassing the pin into the first position.

3. A platform as claimed in claim 2, in w1iich the pin also passes into an aperture in a bracket in the first position.

4. A platform as claimed in claim 3, in which the pin passes through the aperture in the support element and the aperture in the bracket when in the first position.

5. A platform as claimed in any one of claims 2 to 4 in which the pin is attached to the working platform by an elongate member.

6. A platform as claimed in claim 5, in which the pin is attached to the elongate member at a first end thereof and a second end of the elongate member remote from the first is attached to the working platform.

7. A platform as claimed in claim 6, in which the elongate member is rigidly attached to the working platform and the resiliency of the elongate member biases the pin into the first position.

8. A platform as claimed in claim 6, in which the elongate member is pivotally attached to the working platform and a resilient means acts on the elongate member to bias the pin into the first position.

9. A platform as claimed in claim 8, in which a pair of elongate members and pins are attached to each end of the working platform with a resilient means connected between and acting on both elongate members of each pair.

10. A platform as claimed in claim 9, in which the elongate member is a coil spring.

11. A platform as claimed in any preceding claim, in which each end unit has a base element and a pair of spaced apart vertical support elements, each support element having a plurality of slots therethrough arranged for cooperation with one of the brackets.

12. A platform as claimed in claim 11, in which each vertical support element includes two parallel spaced apart vertical surfaces, each surface having a plurality of slots therethrough with each slot in each of the two surfaces being arranged to be in line with a slot on the other surface.

13. A platform as claimed in claim 12, in which all of the slots are the same size.

12

14. A platform as claimed in any preceding claim, in which the brackets are rectangular.

15. A platform as claimed in claim 12, in which the slots in a first one of the surfaces are larger than the slots in a second one of the surfaces and the brackets taper away from the working platform.

16. A platform as claimed in claim IS, in which each bracket has a cam element at the end thereof remote from the working platform, the cam element being arranged to contact the second surface adjacent a slot.

17. A platform as claimed in any one of claims 12 to 16 in which each vertical support element comprises a channel having a U-shape in cross section with slots through the sidewalls of the U.

18. A platform as claimed in any one of claims 12 to 16 in which each vertical support element comprises a tube having a rectangular cross-section with slots through two parallel faces of the tube.