The present invention relates to a device, a so-called shuttering bearer, for use in the construction of foππwork for casting steps, stairs, etc. , said device including a plurality of substantially identical, mutually sequential, substantially V-shaped or L-shaped hollows or notches which are defined by two mutually perpendicular flank surfaces, wherein each such hollow or notch is associated with form components against which a step of given height and given width is to be cast or moulded, and wherein the height and width can be determined by means of the respective lengths of the two side flanks of the hollow or notch.

Devices, so-called shuttering panel bearers, of substantially the aforesaid kind are known to the art. m the case of known bearers, each bearer must be made to the size for a step of given rise and given width or run. Two or more such bearers are placed substantially parallel with one another and are provided with one form part, such as a prefabricated --te template, at one and the same flank of the hollow or notch for the purpose of moulding a horizontal part of the step, the tread, and to provide the other flank with a form part intended for casting a vertical part of the step, the riser. In order to provide a cαπplete form for moulding steps of well-defined lengths, the bearer is complemented with side members, stringers. When using foππwork of this kind, it is necessary to manufacture, store and handle a very large number of these so-called bearers, which is extremely costly and requires cαπprehensive planning for future requirements.

In the case of curved or spiral stairways, a substantial part of the form is constructed on each casting or moulding occasion, which is extremely time-consuming and therewith expensive. It is also very difficult to maintain the accuracy required with respect to measure¬ ments.

The present inveπ' ^{* *} ~n provides a solution to the aforedescribed drawbacks associate with the known technique.

The invention thus relates to a so-called bearer for use in stair foππwork, conprising a plurality of substantially identical, mutually sequential hollows or notches defined by two mutually perpendicular flank surfaces, such as substantially V-shaped or L-shaped hollows or notches, where each hollow or notch is associated with form parts against which moulding is effected to produce a stair step of given height and given width, wherein the height and width of the step can be determined by means of the respective lengths of the two flank surfaces of said hollow or notch.

The inventive bearer is particularly characterized in that it includes a plurality of mutually sequential and mutually equidistant support elements which can be displaced mutually to form said hollows or notches, where appropriate by means of support parts which coact to form a respective flank, and in that means are provided for mutual and simultaneous displacement of said support elements to establish equidistant spacing therebetween.

The invention will now be described in more detail with reference to exeπplifying emb iiments thereof and also with reference to the accαrrpanying drawings, in v ^* hich

Figure 1 illustrates schematically a first embodiment of an inventive device, seen transversely to its longitudinal axis; - Figure 2 illustrates the device of Figure 1, as seen from the left in Figure 1;

- Figure 3 illustrates schematically a first embodiment of a lever system v ^* hich functions to extend and to shorten the rows of support elements of the device illustrated in Figure 1, seen transversely to its longitudinal axis, and further illustrates a system for rotating said support elements;

- Figure 4 illustrates the system shown in Figure 3, seen from the left of Figure 4;

Figure 5 illustrates schematically support elements substantially according to Figure 1, as seen in Figure 1;

- Figure 6 illustrates schematically a second embodiment of an inventive device intended for moulding or casting curved stairways and seen axially from above in a section taken on the line A-A

in Figure 7;

Figure 7 is a sectional view taken on the line B-B of the device illustrated in Figure 6;

Figure 8 illustrates schematically the end surfaces of a support element of the device shown in Figures 6 and 7, seen from the right in Figure 6; and

Figure 9 illustrates schematically an embodiment of an inventive support element as seen in Figure 8, this embodiment being preferred in some cases.

The inventive device, or bearer, illustrated in Figure 1, comprises a plurality of mutually sequential and substantially similar hollows or notches 1 which are defined by two mutually angled flank surfaces 2, 3. According to one often preferred embodiment, the hollows are either substantially V-shaped or substantally L-shaped. Each hollow l is intended to aαxππmodate form parts 4, 5 against which concrete is to be cast in order to produce a step 6 of given height and given width, said height and width being determined by means of respective lengths of the two flank surfaces 2, 3.

One or both of the form parts 4, 5 may comprise suitable, conventional shuttering panels or prefabricated step parts forming the tread 7 or riser 8 of said step configuration. Thus, casting results in the concrete cup 6 ¹ of the step and, where appropriate, also the tread and/or riser.

The device includes a plurality of mutually sequential and substan- tiallly equidistant support elements 9 which can be displaced mutually to define a hollow or notch 1 between pairs of such elements. The support elements 9 include two support parts 10, 11 which can prefer¬ ably be moved relative to one another essentially at right angles, so as to form a respective flank 2, 3 of two separate hollows or notches 1, as shown in Figure 1.

As will be made apparent in the following, means are provided for mutual and essentially simultaneous movement of the support elements 9 in a manner to maintain equidistance therebetween.

As will also be apparent from the following description, means are preferably also provided for rotating the support elements substan¬ tially simultaneously around a respective pivot axle 12 vtαich extends substantially at right angles to the geometric extension of the element rows at respective elements, as shown in Figure 4, said pivot means functioning to adjust the angle at which the support parts 9 are inclined to said row extension, and therewith also the lengths of respective flanks 2, 3, as illustrated schematically in Figures 1 and 5.

According to one preferred eitibodiment, illustrated in Figures 3 and 4, the support elements 9 coact with a lever system Λiic can be lengthened and shortened such that a change in the length of said lever system will be distributed equally between all the spaces 9' between respective support elements 9. According to one embodiment, each of the support elements 9 has a guided moveable guide part 13, a slide part 13, ^* *7hich is connected to a first lever 14, the upper end 15 of which, i.e. a first end 15, is pivotally attached to the slide part 13 by means of a pivot attachment 16, and the lower end 17 of which, i.e. the second end 17, extends down from said slide part 13. The second end 17 is pivotally connected, when appropriate, to a second lever 19, i.e. a connecting lever 19, by means of a pivot attachment 18. This second lever 19 extends to a pivoted attachment 14• located centrally between the upper pivot attachment 16 and the lower pivot attachment 18 of the corresponding first lever 14 of the adjacent support element and, where appropriate, to the upper pivoted attachment 16 of the corresponding lever 14 of the support element 9 located after the adjacent support element 9, as illustrated in Figure 3. Certain lever connections are omitted at the ends of the system, for natural reasons. Thus, no connecting levers 19 extend to the first lever 14 located furthest to the right in Figure 3, this lever being intended for connection to an end-support part 13. The lever system should be attached to at least one fixed point, in order to provide a well-defined lengthening and shortening movement. In many cases, it is preferred to locate said fixed point adjacent a terminal first lever, such as the lever 14 shown furthest to the right in Figure 3. Aαxϊrding to one preferred embodirnent, the pivot attachment 16, and therewith also the corresponding slide part 13, is

connected to a slide surface 13• on which the remaining slide parts 13 are intended to slide.

It can be said generally that at least part of the support elements 9 project -upwards from a slide path along which the support elements are guided for movement.

The embodiment illustrated in Figures 1-5 also includes support- element camming devices 20 vhich are intended to move reciprocatingly in the direction of the element rcws and to be raised and lowered by coaction with a substantially fixed abutment 21 and therewith act on the support elements in a manner to rotate said elements in one direction or the other about said pivot axle. It is not nececessary per se to provide a separate camming element for each support element, since conditions are conceivable in * ^* hich same support elements cannot be associated directly with an individual camming element 20, and constructions are conceivable in which only one or two angled guide surfaces 24 or the like are provided for all of the support elements. What is important in this respect is that a support-element guide surface 23, or like surface, can be raised and lowered in a manner to achieve rotation of the -support elements, wherein at least one camming element shall be provided. Other solutions are conceivabl per se for achieving rotation of the support elements.

According to one preferred einbodimeπt, the guided slide part 13 of the support element 9, together with said support parts, can be rotated about said pivot axle by means of a contact part 22 which is intended to rest on a camming element 20 and therewith be rotated by raising and lowering the camming element. In the majority of cases, it is preferred that the camming elements are mutually connected sequentially in rows, wherein each camming element includes a sub¬ stantially wedge-shaped element having a first guide surface 23 which extends substantially in the direction of said rows of support elemen and which coacts with a support element, and a guide surface 24 which is angled in relation to the first guide surface 23 and vhich is intended to rest on said substantially fixed abutment and to be moved reciprocatingly in relation thereto while raising and lowering the camming element, as will be evident from Figure 3.

For the purpose of altering the length of the lever system, there is provided, for example, a screw device (not shown) marked with a crank 25 in Figures 1 and 2, by means of which a pulling or pressing force in a manner obvious per se can be exerted on the lower end of the terminal lever 14 located nearest the screw device, so as to displace said end longitudinally, and therewith all of the support elements of said system.

Rotation of the support elements is achieved, for instance, in a corresponding manner with the aid of a screw device (not shown) , indicated by a crank 26 in Figures l and 2, by means of ^* rfich a pulling or pressing force in a manner obvious per se can be applied to the end of the row of mutually connected camming elements located nearest the screw device.

Various types of devices corresponding essentially to the type illustrated in Figures 1-5 are conceivable for use in constructing different types of stairs. According to one embodiment, the rows of support elements are substantially straight and herewith substantially parallel with a straight line, as in accordance with Figures 1-5, said device being intended for the casting of a straight stair with only one inclination. Ai-xxsrding to another earcibodiment (not shown) , the rows of support elements extend in the form of a spiral, wherein the foππwork constructed with the aid of the inventive device is intended for casting a curved stairway. Each tread has a width which varies along the step. The device is suitable for c action with an outer, curved string, an outer form sidepiece and an inner form sidepiece, having either the form of an inner, curved string or the form of a so-called axle or spindle of substantially conventional construction.

The exeπplifying embodiments of the inventive device illustrated in Figures 6-9, intended for casting spiral or curved stairways, support elements 9 are disposed in rcws which extend substantially radially from a column part 27 or like load-bearing element. In this case, the support elements are displaceable substantially in the axial direction of the column part 27 and are pivotable substantially about the axial

direction of said column part 27.

Also shown is an eπibcdiment in vhich the column part includes a substantially cylindrical shell 27', a wall 27', wherein at least part of the devices intended for simultaneous displacement of the support elements 9 are arranged in the column part 27. Also shown is a preferred embodiment in which an extendable and retractable system of levers 14, 19, corresponding to the system illustrated in Figure 3, is arranged in the column part and is intended to coact with the support elements in a manner to displace the same siirailtaneously, via guide parts 28 via the wall 27' .

In this case, the guide parts 28 have the form of sleeve parts 28 which are guided for movement along the column part and vhich carry and displace a respective individual support element. The column part is provided with at least one axial slot 29 through vhich the guide parts 28 are connected with the lever system by means of connectors 30.

In this case, the support elements are mounted to the column part by means of a sleeve-like part 9" vhich is carried by a guide part and v/hich is guided for movement externally in relation to a guide part. I_rcfl_cdiments are conceivable in which the support elements 9 are guided for movement adjacent the column part.

In order to retain the setting of the support elements 9, said elemen are releasably affixed relative to one another and relative to the column part. This has been indicated with a slot 31 in the sleeve- like part 9" and with the lugs 32 coacting with the slot and function- ing to enable the support element to be clamped firmly by means of a bolt joint 33 or by means of hydraulic or pneumatic devices (not shown) .

According to one preferred embodiment, the support elements are supported at their periphery 9' ' ', at their free end 9« " , by means of support parts 34, vhich are intended to support against the ground 35, or corresponding surface 35. The support parts are preferably displaceable and capable of being fixed to the support elements in

some suitable manner (not shown) .

Figure 9 illustrates an arrangement of support elements, which is preferred in some cases, said arrangement including a substantially radially extending beam or bar element 36, such as a so-called square tube, vhich is intended to support a first shuttering panel 37 transverese its axial direction, said shuttering panel being intended for the casting of a step tread, wherein arranged adjacent one such first shuttering panel 37 are two second shuttering panels 38 which extend substantially parallel to the axial direction and extend on mutually opposite sides, the upper side and the lower side, and essentially at opposite edges of said first shuttering panel, said second shuttering panels being intended for the casting of a step riser, wherein a first shuttering panel and a second shuttering panel form one of said hollows or notches.

In casting or moulding devices of essentially the kind exeπplified in Figures 6-9, the form cavity is closed radially and circumferentially by means of an outer, curved string 39, an outer form sidepiece 39, and an inner form sidepiece 40 vhich may either have the form of an inner, curved stringer 40 or an axle or spindle (not shown) . The form sidepieces 39, 40 preferably connect with the surfaces against vhich the tread and the riser of said step are to be cast, as indicated in Figure 9.

The working manner of the inventive device will be understood in all essential details from the aforegoing. Thus, the support elements can be moved in relation to one another by means of a suitable mechanism in a manner to maintain equidistance between said elements, therewith enabling the flank lengths of the hollow or notch to be varied.

In the embodiments illustrated in Figures 1-5, the support elements are rotated about the aforesaid pivot axle by means of additional devices. By rotating and displacing the support elements, it is possible to vary the height and the width of the step to be cast or moulded, by variation in the extension of respective flanks.

In the case of embodiments substantially similar to the type

illustrated in Figures 6-9, the support elements can be displaced and pivoted simultaneously for the casting of spiral or curved staircases enabling the rise, etc. to be varied. Furthermore, the direction in vhich the stairway spirals or curves can be selected freely in each separate casting, if desired, by adapting successive settings of the support elements in the circumferential direction. By placing a large swing between a pair of mutually adjacent support elements, it is possible to provide a small landing in the stairway. One method of setting the device, is to adapt the strings for attachment at a given radial position and to adjust the support elements against the string or strings and then fixate the support elements. In this case, the lowermost support element is preferably stationary.

In the case of the illustrated mechansim for displacing the support elements, the support elements are acted upon simultaneously via the levers, so as to maintain equidistance between the support elements.

As will be apparent from the aforegoing, the invention provides a highly rational and attractive foππwork for casting stairs, both straight and curved stairs.

The invention has been described in the aforegoing with reference to a number of exeπplifying embodiments thereof. It will be understood that other embodiments and minor modifications are conceivable, without departing from the inventive concept.

For instance, the lever system can per se be replaced with a system of screw elements for mutually moving the support elements, said screw elements having mutually successively increasing pitches so that equidistance can be maintained even when all support elements are displaced simultaneously by means of a common rotational movement.

In order to produce a tread vhich has a freely outwardly projecting part in relation to respective underlying risers, in accordance with Figures 1-5, the support parts intended for the casting of risers can be provided with a recess 27, as illustrated schematically in Figure l.

As will be understood, prefabricated step parts can also be used in essentially the type of embodiment illustrated in Figures 6-9, -said step parts being arranged in the inventive device prior to casting, so as to enbody said step parts.

Furthermore, the angle between the flank parts forming a hollow or notch need not necessarily be 90°, since other angles, both acute and obtuse, are conceivable.

Many different configurations of the device illustrated in Figures 6- 9 are conceivable for the construction of curved or spiral stairways. According to one preferred embodiment, the free edge of the tread, i.e. the outer corner when seen in cross-section, is displaced from the centre axis of the stairway ty about 50 mm.

The guide parts 13, 28 are preferably guided, although requisite guiding of the device can be achieved in some other way.

At least in the embodiments illustrated in Figures 1-5, it is natural that pairs of support elements will form a hollow or notch 1 there¬ between, and that support parts of one support element will coact to form an individual flank of two mutually separate hollows or notches. However, it is conceivable to define a hollow or notch essentially with one and the same support element, particularly in the case of the embodiments shown in Figures 6-9.

The invention shall not therefore be considered limited to the afore- described exemplifying embodiments thereof, since modifications can be made within the scope of the accαπpanying Claims.