GB2221241A

GB2221241A - Platforms for ladders

Info

Publication number: GB2221241A
Application number: GB8909831A
Authority: GB
Inventors: Ronald Thompson
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-07-27
Filing date: 1989-04-28
Publication date: 1990-01-31
Also published as: GB8817923D0; GB8909831D0

Abstract

A step ladder of the kind having a flight of steps 1 and a frame pivoted to the top to provide support, and which includes a platform 12 which is additional to or replaces the frame. When the platform replaces the frame as shown, one end of the platform 12 is pivotally attached to the flight of steps at or near the top thereof for pivotal movement between a rest position in which it is folded against the steps for storage and a working position shown in which it makes a smaller obtuse angle with the steps and said step ladder further includes means preventing the platform opening beyond tho angle of said working position. When the platform is additional to the frame (not shown) the platform is pivotally attached to the back of the step ladder at or near the top thereof for pivotal movement between a rest position in which the platform is folded against the frame of storage and a working position in which with the foot of the frame spaced from the flight of steps to provide support therefor the platform extends substantially horizontally away from the frame and the stop ladder further includes means supporting the platform in said working position. The platform may itself be telescopic, and could form the frame to support the flight. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO STEP LADDERS This invention relates to improvements in or relating to step ladders which substantially enlarge their usefulness.

Step ladders, sometimes known as pairs of steps, comprise a portable flight of flat broad steps or treads pivoted at the back, at or near the top, to a frame which is usually in the form of a braced pair of legs and which can be folded against the steps for storage or pivoted to space the base of the frame away from the steps to provide support.

In accordance with one embodiment of the present invention, the frame is replaced by a platform one end of which is pivotally attached to the flight of steps at or near the top thereof for pivotal movement between a rest position in which it is folded against the steps for storage and a workin position in which it makes a small obtuse angle with the steps. Locking or stop means, or both, are provided to prevent the platform opening beyond the angle of the working position when in use.

When in use with the platform opened to the working position, the sole or principal support for the upper end of the flight of steps is provided by the platform which extends substantially horizontally and the free end of which bears against a wall or like vertical surface while the foot of the flight of steps rests on the ground.

This embodiment of the invention provides four important advantages over conventional step ladders which greatly enlarge their usefulnèss.

Firstly, it enables a workman standing on the steps to be positioned a comfortable distance away from and facing a wall on which a work operation is to be performed. Secondly, since only the feet of the flight of steps touch the ground, it is possible to place it to bridge flower beds or other areas where it would be inconvenient or dangerous to locate the foot or feet of the usual supporting frame. Thirdly, it provides the workman with a convenient platform for his tools, paint pots, etc. Fourthly, it provides an ancillary support for wallpaper at a level significantly above floor level so that the workman does not have to support the weight of a whole floor-to-ceiling length of the paper when hanging it. Other advantages will also occur to those occupied in building repair, decoration and home improvement work.

The height of the flight of steps is not critical but it will normally have about 4 to 7 treads.

The platform length is chosen such that an operator standing on the steps is located at a convenient rkig distance from the wall or other working surface against which the free end of the platform bears in use.

Generally this will be in the range 15" to 24", preferably 16" to 20".

The ideal platform length is about 18".

The angle of the platform to the flight of steps in the working 0 0 position will normally be in the range 105 to 115 to provide a cs-,venient climbing angle. The angle of the working position will preferably be preset but it may be made adjustable to provide the operator with greater flexibility of the configuration of the ladder and platform.

Where stop means are provided, they may conveniently comprise a first face provided on the platform and adapted to bear against a second face provided on the flight of steps when the platform is opened to the working position. Alternatively or additionally, they may be provided by a hinged bracket or hinged brackets by which the platform is pivotally attached to the flight of steps. Examples of suitable brackets are those marketed by McPhersons of Benfleet, Essex, England, under the Code Numbers 4860A and 4861A.

If desired, the stop means may be adapted to permit free movement of the platform to angles greater than that of the working position prior to use while being adapted to engage with the platform to prevent it opening to such greater angles when in use.

The stop means are provided to prevent the platform opening to an angle greater than that of the desired working position while the weight of the ladder, or of the ladder and an operator standing on the ladder, pushes the platform against the wall and prevents it from closing to a smaller angle. Alternatively or additionally, however, locking means may be provided for locking the platform in the working position and thus preventing it closing to a smaller angle.

Several variations of this embodiment of the invention are possible.

For example, the length of the flight of steps may be adjustable, e.g. by forming the flight in two or more sections which may, for example, be arranged to slide over each other or be hinged so that they can be folded together when the full length is not required.

The length of the platform may also be adjustable so that the distance from the top of the steps to the wall may be varied. For\ example, the nose of the platform may be mounted on telescopic arms with means for locking the arms in at least one extended position. In one particular embodiment of this variation, the platform may be extended to a length such that it may form the conventional support frame for a pair of steps.

In accordance with another embodiment of the invention, a platform is pivotally attached to the back of a step ladder, at or near the top thereof, for pivotal movement between a rest position in which the platform is folded against the frame for storage and a working position in which with the foot of the frame spaced from the flight of steps to provide support therefor, the platform extends substantially horizontally away from the frame. Means, such as a strut or struts, are provided for supporting the platform in said working position.

The platform may be attached to the back of the frame or to the back of the flight of steps above the frame.

An important advantage of this embodiment of the invention is that it provides the workman with a larger and less constricted working platform than that of a conventional step ladder where the working platform, if provided at all, is located below the top and between the flight of steps and the frame and is thus both constricted in area and difficult to get at from some angles.

In a preferred variation cf this embodiment, the arrangement is such that the platform may also be opened away from the frame, when the frame is closed against the flight of steps, to a position in which the platform forms a small obtuse angle with the steps. Locking or stop means, or both, are provided to prevent the platform opening beyond this angle so that with this variation this second embodiment of the invention may additionally be used in the same manner as the first embodiment.

The invention will now be described with reference to preferred embodiments thereof and with the aid of the accompanying drawings in which Figure 1 illustrates one form of the first embodiment of the present invention (not to scale) shown in the rest position, Figure 2 is the same embodiment shown in a working position, Figure 3 is an enlarged side view of a portion of another version of the first embodiment according to the present invention, Figure 4 shows four alternative working positions of yet another version of the first embodiment of the invention, and Figures 5 and 6 illustrate a preferred form of the second embodiment of the invention.

Referring to Figure 1 of the drawings, 1 indicates generally a flight of steps having a pair of legs 2, and five treads 4. In the drawing the legs are shown as parallel but they may be splayed outwardly from top to bottom. Attached to the back of the upper end of the flight of steps is a strengthening plate 6 and on the outer surface of each of the legs 2 are attached generally trapezium-shaped blocks 8. The upper and lower faces of these blocks 8 are parallel and generally horizontal when the ladder is at its working angle (generally about 150 to 350 to the vertical and more usually around 200 to the vertical), the rear face of each block is parallel to the outwardly facing face of the legs 2, that is, at an angle of about 700 to the bottom face of the block 8, and the forward face 10, which provides one face of a stop to be described below, is at a similar angle to the bottom face of the block 8.

Pivotally attached to the flight of steps in a manner described below is a platform generally indicated at 12, comprising a board 14 having a rear edge 16 and a front edge 18 and a pair of spaced parallel support rails 17 which are mounted to the under face 13 of the board 14 and extend from front to rear of the board but stopping short of the rear of the board 17, as best shown in Figure 1.

The support rails are spaced the same distance apart as the blocks 8 attached to the legs 2, and the platform is attached by flap hinges 19 one half of each of which is attached to the under face of one of the rails 17 the other half being attached to the under face of one of the blocks 8 so that the platform can pivot between a rest position, in which it is folded against the flight of steps (see Figure 1) and a working position in which it makes a small obtuse angle with the flight of steps (see Figure 2). The rear face 20 of each of the rails 17 is chamfered (as best shown in Figure 2) so that when the platform has been opened to the desired small obtuse angle, the face 20 bears on the corresponding face 10 of a block 8 to form a stop which prevents the platform being opened to a greater angle.The small obtuse angle is chosen such that the platform is generally horizontal when the flight of steps is at a convenient angle for climbing and standing on. Generally, this small obtuse angle will be about 1050 to 1250.

In the embodiment illustrated means are provided for adjusting the length of the platform, and thus the distance by which the top of 'the ladder may be spaced from the wall 34, comprising a bar 22 and rearwardly extending arms 24 each mounted on a respective rail 17 by stud bolts 28 extending through longitudinal slots 30 in the rails whereby the arm is free to slide forward and back relative to the rail and be lockable in any desired position by means of wing nuts 26 engaging the stud bolts 28. With the bar closed against the free end of the platform, the platform length is about 18 inches but this can be increased to nearly double this length by pulling the extending arms out to their full length.

In operation, the platform is opened until the faces 20 of the rails 17 bear on the corresponding faces 10 of the blocks 8 and the flight of steps is positioned with the front of the free end of the platform, which in the embodiment is nose bar 22 but in other cases may be front edge 18, bearing against a wall or other vertical surface 34.

Further stop means are provided by the underface 13 of the platform board 14 extending rearwardly of the rails 17, which face, when the platform is in the working position, bears on co-operating top faces 32 of the legs 2.

The weight of the flight of steps, with or without an operator standing on it, pushes the platform against the wall and the resulting frictional force with the wall prevents the weight of the platform from causing it to collapse downwardly. However, where it is desired for the platform to take considerable weight, such as of a person, it is advisable to provide locking means (not shown) which will lock the platform in the working position when engaged.

The feet of legs 2, and also the face of bar 22 may be provided with e.g. rubber pads, to reduce danger of slipping. Recesses ma be provided in the platform 4, if desired, to receive paint pots or tools and/or clips may be provided for holding tools.

Figure 3 shows an enlarged side view of a portion of a variation of this embodiment of the invention in which a different method of hinging together the rails 17 and the blocks 8 is employed. Details of the arrangement which are not relevant to the hinging mechanism have not been shown in Figure 3.

In this embodiment the blocks 8 are pivotally hinged to the rails 17 by side hinges generally indicated by 40. Each side hinge comprises a first metal plate 42 fixed to a block 8 by means of screws 44 and pivotally attached by pin 46 to a second metal plate 48 fixed to a rail 17 by means of screws 50. A flap of metal 52 extends from the upper side of plate 48 and overlies plate 42 when the platform is in the working position thus preventing hinge 40 from opening to a larger angle. Hinge 40 therefore also acts as a stop means additional to the stop provided by the rear face 20 of the rail 17 bearing on the face 10 of the block 8.

Further or alternative stabilisation of a ladder according to the present invention when in the working position may be provided by the use of one or more folding struts one end of each of which being connected to the strengthening plate 6 or to a leg 2 of the ladder and the other end of each being connected to the underside of the platform cr to a rail 17 as appropriate. The struts will be designed to fold when the ladder is closed to the rest position but to lock open when the ladder is in the working position.

The embodiments illustrated in Figures 1 to 3 are suitable for manufacture from wood. However, ladders according to the invention may also be made of metal, e.g. aluminium.

In another embodiment, the stop means provided by faces 10 and 20 of the embodiment of Figures 1 to 3 may be replaced by use of hinged brackets incorporating faces which will provide the stop means. Such brackets are available commercially.

In yet another embodiment, locking means may be provided in place of or in addition to the stop means. For example, hinged brackets are available commercially which incorporate locking means which have releasable means for locking the two flanges of the bracket at a particular angle to each other and which are sufficiently robust for use for the present invention.

Where the length of the platform can be extended so that it can, with the flight of steps, be used as a step ladder in conventional manner, it can be used in a variety of working positions as illustrated very diagrammatically in Figure 4 and this provides a very versatile accessory for a painter and decorator. It is moreover very compact when folded and is easily transportable. Referring to Figure 4, Figure 4A shows the steps 2 with the platform 12 folded against them, resting against a wall 34, for use as a simple ladder. Figure 4B shows the same apparatus with the platform opened to a first work position but in its non-extended form. In Figure 4C, the platform has been partially extended to provide greater spacing of the ladder from the wall and in Figure 4D the platform is fully extended, using two telescopic pieces, and the platform is opened to a second work position (intermediate the folded position and the first work position) so as to form a pair of steps.

For use in the position shown in Figure 4D, the apparatus may further include a flap mounted either at the top of the ladder or on the rear end of the platform and pivotable from a rest position where it is folded flat against one face of the rails of the ladder or against a face of the platform, respectively, to a position where it rests across the top of the ladder and the rear end of the platform, to form a horizontal surface on which to place articles such as paint cans.

Means may be employed to prevent the platform opening beyond the second working position when the apparatus is to be used as a pair of steps.

Referring now to Figures 5 and 6, a preferred form of the second embodiment of the invention comprises a step ladder 102 comprising a flight of steps 104 attached near the top by hinges 106 to a conventional support frame 108 in the form of a braced pair of legs.

Attached by hinges 110 to the back of the steps above the frame is a platform 112 comprising a pair of rails 114 supporting transverse slats 116 to the underface of which is attached to member 118. Attached to a bracing member 120 of the frame 108 is a strut 122 the free end of which engages in a hole in the underside of platform member 118. Two holes are provided in the member. The first, 124, is located in such a position that with the foot of the frame spaced from the foot of the steps in conventional manner to provide support therefor, the platform will be supported substantially horizontally when the free end of each strut is located in the hole. The second, 126, is located in such a position that when the support frame remains closed against the flight of steps the struts will support the platform at an angle relative to the flight of steps similar to that shown in Figure 2. In that \ position, the platform is prevented from opening to a wider angle by face 128 of the rearmost slat of the platform bearing against a face 130 of the topmost tread 132 of the flight of steps.

Claims

1. A step ladder having a platform, said platform replacing the frame or being additional to the frame, and wherein, when the platform replaces the frame, one end of the platform is pivotally attached to the flight of steps at or near the top thereof for pivotal movement between a rest position in which it is folded against the steps for storage and a working position in which it makes a small obtuse angle with the steps and said step ladder further includes means preventing the platform opening beyond the angle of said working position, and when the platform is additional to the frame the platform is pivotally attached to the back of the step ladder at or near the top thereof for pivotal movement between a rest position in which the platform is folded against the frame for storage and a working position in which with the foot of the frame spaced from the flight of steps to provide support thereof the platform extends substantially horizontally away from the frame and the step ladder further includes means supporting the platform in said working position.

2. A step ladder as claimed in Claim 1 wherein the platform replaces said frame and said preventing means comprise stop means comprising a first face provided on the platform and adapted to bear against a second face provided on the flight of steps when the platform is in the working position.

3. A step ladder as claimed in Claim 1 wherein the platrorm replaces said frame and said preventing means comprise stop means comprising a first face provided on the platform and adapted to bear against a second face provided by at least one hinged bracket.

4. A step ladder as claimed in Claim 1 wherein the platform replaces said frame and said preventing means comprise locking means for locking the platform in the working position.

5. A step ladder as claimed in Claim 1 in which the platform is additional-to the frame and which is constructed and arrangedsuch that with the frame closed against the flight of steps the platform is able to adopt a position in which it forms a small obtuse angle with the steps and said step ladder includes means preventing the platform from opening beyond this angle.

6. A step ladder as claimed in Claim 5 wherein said preventing means is as claimed in any one of Claims 2 to 4.

7. A step ladder as claimed in Claim 1, substantially as described.

8. A step ladder as claimed in Claim 1, substantially as shown in Figures 1 and 2 of the drawings or in Figures 1 and 2 as modified by Figure 3 or as represented diagramatically in Figure 4 or as shown in Figures 5 and 6.