A STAIRCASE WORKING PLATFORM

Abstract: An adjustable platform arrangement for angled stairs or curved stairs includes a generally rectangular platform (10). One long side (11) of the plarform is intended to lie along the rearward edge (71) of a stairstep. The short sides of the platform (10) have a length which is smaller than the length of the long side (11). The short sides will preferably have a length of about 40 cm and the long sides will prefereably have a lenght of about 75 cm. At each end of the long side distance from the stairstep (7) which supports the platform (10) is an adjustable support leg (21) which extends in a plane normal to the platform surface and which can be locked selectively in an axially extended position. As a result of the dimensioning of the platform, the support leg (21) at the inner curve of a step need not have a greater length beneath the platform surface than about 51 cm, which provides the platform with good stability and also room for placing a stepladder steadily on the platform.

Description: λ STAIRCASE WORKING PLATFORM The invention relates to a staircase working platform of the kind defined in the preamble of Claim 1. The walls which define the stairwells of domestic buildings, particularly multistory buildings, have regions which are not easily reached and in which light fittings, ornaments, pictures, curtain fittings, etc., are to be placed, or in which such articles have already been placed and which must be reached for cleaning and maintenance purposes, or for other reasons. In order to reach these high stairwell regions, it is necessary to use a stepladder, or preferably a so-called stair ladder. Such stair ladders are normally constructed to stand on a horizontal support, In the case of the stairways in domestic buildings, or multistory buildings, it is therefore normally necessary to construct a stable horizontal platform on which a stair ladder or stepladder can be placed securely. DE-A-2 404 213 teaches a spacing block whose height corre¬ sponds to the height of a stairstep, and a platform plate whose one end is supported by the spacing block which rests on a stair step, and whose other end is supported by an adjacent, higher stairstep. GB-A-2 208 172 teaches a platform for a straight staircase, wherein the platform extends over several steps and is provided at its outer ends with support legs of given length, so as to enable the platform can be positioned horizontally. The platform has a coaming or upstanding surround extending around its perimeter and is dimensioned to support a so- called stepladder. FR-A-2 663 075 teaches a platform for straight stairs, this platform having the construction defined in the preamble of Claim 1. Although the aforedescribed known technigue provides solu- tions to the problem of erecting horizontal platforms on straight staircases, these solutions cannot be applied in connection with conventional angled or curved stairways in domestic dwellings or multistory buildings, wherewith particular problems arise due to the curvature of the stairways and stairs and stairsteps. WO 9200432 teaches a platform support construction for use with curved or angled stairs, this support construction being intended to avoid the problems associated with the curvature or angling of the stairs. The solution proposed is complex and therewith expensive, and involves supporting the outer ends of the platform on a vertically adjustable stand, which is in turn mounted for rotation about a vertical axle on a tripod provided with height-adjustable legs, each of the three legs being intended to rest on a respective stairstep. The object of the present invention is to provide a working platform that can be used with the majority of types of curved or angled stairways and staircases and which has a simple construction. This object is achieved with a working platform of the kind defined in Claim 1. Further developments of the inventive platform are defined in the dependent Claims. It will be understood that the working platform can also be used in connection with straight stairways and staircases and also generally on inclined support surfaces, for instance in connection with sloping floors in cinemas, theatres, communi- ty halls, and like places, where it is necessary to place a stepladder on a stable horizontal platform support that can be erected on the sloping support surface. A basic feature of the invention lies in the concept of using a simple rectangular platform-plate provided with height- adjustable support legs at each end of one long side of the platform, and ensuring that the short side of the platform has a length which is sufficient to enable the support leg to be placed in the "outer curve" of a stairstep at a safe distance from the forward edge of the immediately adjacent and downwardly lying step, and ensuring that the support leg at the outer end of the platform finds support on the third downwardly lying step at a safe distance from its forward edge at the "inner curve" of the step. Thus, by giving the platform a specific length in the direction of the short sides, for instance a length of about 75 cm, room is provided on the platform for a conventional stepladder, and the support legs need not be longer than is necessary for the furthest positioned support leg to be supported at a point located at a distance of about 51 cm (three steps) from the underside of the platform, at the same time as the support legs rest on respective steps at a safe distance from their forward edges. According to one preferred embodiment of the invention, the dimensions of the platform along the long edge are chosen to be smaller than the width of the stepladder, so that the platform can be moved in the direction of its long edges and therewith ensure that the longest support leg (in a curved stairway) will obtain positive support at a distance from the outer edge of the step in guestion. According to another embodiment, the platform includes a stanchion or post which is intended to support a shelf structure or a toolbox. This provides the person working on a stepladder supported on the working platform to lay out tools, such as electric drilling machines, hammers, paint- brushes, etc., and such material as paint pots, or paint cans, nails or the like, comfortably on a level located in the vicinity of the workman's position on the ladder. The support legs can be locked in selected positions. Alternatively, the support legs may be arranged so that they can be locked in predetermined displaced positions, prefer¬ ably spaced equally apart. The support legs may be guided in guide sockets attached to the platform, said support legs being held securely in the sockets with the aid of clamping devices or locking bolts which extend through mutually aligned holes in respective sockets and support legs. An exemplifying embodiment of an inventive working platform will now be described in more detail with reference to the accompanying drawing, in which Fig. 1 is a schematic front view of a curved stairway and an inventive platform; Fig. 2 is a horizontal view of the stairway and platform shown in Fig. 1; Fig. 3 is a schematic sectional view of the platform; and Fig. 4 is a schematic front view of the platform and illus¬ trates a tool lay-out structure. Figs. 1 and 2 are intended to illustrate a flight of angled stairs where the steps 7 at the angled part of the stairs have a generally wedge-like configuration, as indicated in Fig. 2. The steps 7 have an essentially constant length Δf throughout the entire flight of stairs, along the centre line 8 thereof. Each of the steps 7 has a reward edge 71 and a forward edge 72. Risers are normally provided at the rear edge 71 of respective steps and extend up between respective stair treads from said rear edge to the forward edge-part 72 of the nearest overlying step. The inventive working platform 10 is rectangular and has a long side 11 of length r and a short side 12 of length 1. The straight section of the stairstep has a width R. The platform 10 is comprised of a frame having L-shaped profiles which are connected so that their one leg 141 will form a perimetrically extending and horizontal support for a platform plate 15, wherein the other legs or flanges 142 of said profiles 14 extend slightly above the upper surface of the plate 15 to form a coaming-like surround. A guide socket 20 is mounted firmly on each end of one long side of the platform 10. The socket 20 may have the form of a square-section tube and is positioned so that its long axis will be perpendicular to the plane of the plate 15. A support leg 21, preferably a square-section tube, extends through the socket 20 and can be displaced axially in relation thereto. The support leg 21 can be secured selectively in relation to the socket 20, by means of a locking device 24. This locking device 24 may comprise a screw-threaded hole in the walls of the square socket 20, and a screw 26 provided at one end with a screw-turning device 27, said screw being tightened to firmly clamp the support leg 21. The platform dimension r is smaller than the free width R of the step. The inventive platform is designed to enable it to be mounted also in the corners of the stairs, even in the most awkward position shown in Figs. 1 and 2. It will be seen from Figs. 1 and 2 that the dimensions of the steps in the longitudinal direction of the stairs adjacent the inner curve thereof are relatively small, and it will also be seen that the dimensions of the stairstep 7 in the vicinity of the "outer curve" of the stair are relatively large. The invention proposes particular dimensions, wherein the length 1 is about 50 cm and r is 75 cm. As evident from Figs. 1 and 2, the platform 10 can be placed with its one long side 11 extending along the rearward edge of the stairstep 7, and thereafter moving the support legs 21 in their respective guides 20 so as to support against respective underlying steps 7 with the platform positioned horizontally, whereafter the platform structure is locked firmly with the aid of the locking devices 24. One outer support leg 21 will then rest on the step beneath the step 7 that supports the inner long edge 11 of the platform, while the other support leg 21, at the "inner curve" of the step, will rest on the step 7 located beneath the stairstep that supports the inner edge of the platform 10, said support leg 21 being positioned at a safe distance from the forward edge of the step. The supportive positions of the support legs 21 on respective steps can be adjusted by moving the platform 11 along its inner long edge, provided that the measurement r is such as to enable such displacement in a standard stairway or flight of stairs. Thus, in the case of the illustrated embodiment it is only necessary to be able to move out the support leg 21 located at the "inner curve" of the stairs through a distance h from the support level defined by the inner, under long-edge surface of the platform to the bottom end of the support leg 21, this distance reaching to three times the vertical distance ds between mutually adjacent stairsteps 7, i.e. a distance of about 51 cm. Thus, in order to take into account variations in the height ds, the dimension h should extend to about 60 cm, although h will still be still relatively small, therewith affording good stability to the support leg 22 at the inner curve of the steps and a firm flexurally rigid attachment in its guide socket 20, even when require- ments placed on material and tolerances are low. Because of its length 1 of 50 cm and a length r of 75 cm, the platform 10 will nevertheless enable a conventional stepladder to be placed securely within the coaming-like surround 142, the stability of the stepladder being ensured by virtue of the outwardly projecting support leg having a length h which is as small as three times ds. The use of a structurally very simple rectangular platform that has two freely adjustable support legs at each end of its one long side in an angled stairway is made possible by virtue of the fact that the rectangular platform has been given a short side dimension which is at most about 50 cm. A platform which has a long- edge dimension of about 75 cm will provide room for a conventional stepladder with the ladder posts or feet positioned in a respective corner of the platform. It is essential that the four posts or feet of the stepladder will find support in a respective corner of the platform and that the platform itself is supported by its respective support legs in the corners of the platform, so that the platform supporting points are chosen so as not to limit stability of the stepladder. In the light of this, it is obvious that the actual platform need not necessarily be rectangular but that the corners thereof which are intended to receive respective support posts of the stepladder will preferably lie on the corners of a rectangle. As illustrated in Fig. 4, the platform 10 may include a stand or structure 30 for supporting a toolbox and/or a lay-out plate 32 on which paint pots can be placed for instance, wherein the stand and/or plate are positioned at a height above the platform 10 at which the workman is able to place materials on the plate and tools in the toolbox while standing on a stepladder, or stair ladder, supported by the platform. The stand 30 may include a vertical square-section tube 31 which is fitted on the upwardly projecting end of a support leg 21 and rests on the support-leg guide socket 20. The vertical tubes 31 of the stand 30 may support at their upper ends a plate or a toolbox 32, or may be provided with means for securing the same. Alternatively, the upper ends of the vertical tubes of said stand may support a horizontal beam 33 on which the plate/toolbox 32 may be supported in selective positions therealong. Another alternative is to provide the stand 30 with two vertical tubes 31 which can each be fitted onto an end of a respective support leg and which are connected at their upper ends to the beam 33, which may also function as a guard rail on the platform 10.

Claims: CLAIMS 1. An adjustable staircase working platform arrangement comprising a generally rectangular platform (10) which is intended to be positioned with one side (11) along and adjacent to the rearward edge (71) of a step such that the undersurface of said platform is supported by the stairstep (7), wherein the platform (10) is provided at each end of its opposite edge with an axially extendable support leg (21) which extends perpendicularly to the horizontal plane of the platform (10) and which can be locked in a selected axially extended position such that the ends of respective support legs will support against a stairstep with the platform (10) positioned essentially horizontally, characterized in that the platform has a long side which is intended to lie along the rearward edge of the stairstep, and a short side which is shorter than the long side; in that the short sides of the platform have a length of at most 60 cm; and in that the length of the support legs (21) is chosen to enable the ends of the legs to be placed at a distance of about 55 cm beneath the undersurface of the platform, thereby enabling the platform to be also used in connection with angled steps and stairs, with a maximum support-leg height corresponding to three times the step height of the stairs. 2. A platform arrangement according to Claim 1, character¬ ized in that the short sides of the platform have a length of about 50 cm. 3. A platform arrangement according to Claim 1 or Claim 2, characterized in that the long sides of the platform have a length shorter than 85 cm, preferably a length of about 75 cm. 4. A platform arrangement according to any one of Claims 1- , characterized in that the long platform sides have a length of at least 60 cm, preferably at least 70 cm. 5. A platform arrangement according to any one of Claims 1- 4, characterized in that the platform (10) includes a stand (30) for supporting a lay-out plate or a toolbox (32) at a level above the upper surface of the platform (10). 6. A platform arrangement according to any one of Claims 1- 5, characterized in that the stand (30) is constructed to provide a guard rail along one edge of the platform. 7. A platform arrangement according to Claim 5 or Claim 6, characterized in that the stand includes at least one tubular post which receives the ends of support-legs projecting up beyond the upper side of the platform, wherein the end of said at least one tubular post supports against a support-leg guide socket. 8. A platform arrangement according to any one of Claims 1- 7. characterized in that the short sides of the platform (10) have a length of about 40 cm so as to permit limited dis- placement of the support leg beneath the surface of the platform of at most about 51 cm when the long side of the platform lies along the rearward edge of a stairstep (7) and the platform is horizontal.

Inventors: GRANATH OLLE, GRANATH, OLLE
Applicants: GRANATH OLLE, GRANATH, OLLE
Application year: 1995
Main classification: E04G1
IPC codes: E04G1, E06C7