Description

ADJUSTABLE TELESCOPIC LEVER APPARATUS FOR

LIFTING PLANE ELEMENTS, PREFERABLY WALL AND/OR

COVER PANELS AND ARRANGEMENT FOR FIXING TWO

SLIDABLE ELEMENTS OF POLYGONAL CROSS-SECTION

Technical Field

[1] The present invention relates to an apparatus whereby plane elements, preferably wall and/or cover panels, can be lifted to their place of application. The apparatus typically comprises foot means, vertical lifting means, upper support means carrying the plane element and tilting means inserted in given case in between the vertical lifting means and the support means carrying the plane element. Both the foot means and the upper holding means consists of one or more longitudinal beams and of cross- members which can be fastened to the longitudinal beams. Under the cross-members of the foot means, self-aligning rollers are mounted, and the cross-members of the upper support means are provided with a fastener clip each which allows to support the edge of the plane element at least from below. The invention relates further to an arrangement for fixing in longitudinal direction two elements of polygonal cross-section which are slidable in one another.

Background Art

[2] Various wall and cover panels, such as gypsum plasterboard panels, are widely used for making the coverings of buildings. Given their weight and size (20 kg; 2 m x 1,2 m), without using a proper lever apparatus, their installation and mounting is usually a three-man job, with two men holding the panel in position while the third fixes it to e.g. suspended ceiling joists.

[3] Various lifting apparatuses have been devised to facilitate such work. As different criteria have been taken into account in their design, different solutions have been arrived at. The most general lever apparatuses comprise foot means assembled of rods arranged one way or another, and upper support means. The upper support means can be raised to the desired height by a telescoping mast, and it can also be set in an position other than the horizontal one by tilting means of some sort. Given the fact that the apparatus will be used with panels of various sizes and at various places, various methods of adjustment are used for the beams.

[4] (For the sake of unambiguity, let us make two preliminary remarks before going on with the description. Firstly, by 'width' of the cover panel, we shall mean in every case that direction which is parallel with its bottom and upper edge in case it is mounted in an installation position other than the vertical one, and its 'height' shall be, as a matter

of course, the direction perpendicular to that. Secondly, 'cross-members' of the apparatus mean those elements which are parallel with the vertical plane coinciding with the height direction of the cover panel, irrespective of whether said cross- members are longer or shorter than the elements called 'longitudinal beams', said longitudinal beams being perpendicular to them.)

[5] The apparatus of the simplest design is the one described in US 3,467,261. That apparatus has foot means with trestles, and as the upper support means, too, comprises a single cross-member only so that two such means are needed for working with panels. The cross-member comprises a longer fixed section and a bar, longer than the fixed section, slidably accommodated in the former, with a clip at both ends of it for gripping the plasterboard panel. This embodiment can be used with cover panels of smaller-than-normal heights. In principle, the apparatuses as described in US 4,560,031, and US 5,322,403, respectively, are of a similar design, with the difference that their upper support means has two cross-members, each of which comprises a fixed central section and side sections which are continuously adjustable in it. In the latter apparatus, wooden supporting plates are fastened onto both the central sections and the side sections.

[6] GB 2162815 or US 2006/0065796 describe such apparatuses whereas the size of the foot means cannot be altered, but the central section of the longitudinal beam of the upper support means is of a fixed arrangement, and its two side sections are adjustable. Both the central section and the two side sections are provided with cross-members which are also of a fixed size. This arrangement allows the secure underpinning of cover panels of smaller-than-normal-width, too.

[7] From the point of view of the size of the cover panel, the apparatus described in US

6,176,063 or FR 2741901 qualifies as 'universal'. The upper support means has a single longitudinal beam, comprising, also, a fixed central section and side sections which can be adjusted and fastened within it, on both sides. At the end of each side section, a cross-member is fixed, which in turn has a fixed central section with side sections which are adjustable and securable within it. The foot means is again of a fixed design. As a matter of fact, the apparatus according to US 5,704,755 is similar, with the difference that cross-members are fixed at each end of the central section only of the longitudinal beam of the upper support means, which in turn comprise a central section and side sections which are adjustable and securable within that.

[8] The apparatus described in DE 8909821U is similar in terms of its operation to the ones described above, but its design is somewhat more complicated. The foot means is of a fixed design in this case, too. The upper support means has two longitudinal beams, comprising three sections each: a central fixed section and side sections slidable and adjustable within that. The cross-members are secured to the ends of the

side sections, and have an adjustable section, too, at one end. The apparatus described in US 7,048,258 is similar, except for the fact that the upper support means has four cross-members. Each cross-member comprises a central section and side sections slidably accommodated and gradually fixable by pegs within it. The two longitudinal beams also comprise three sections each, the central ones being fastened to the end of the respective side sections of the cross-members, and the side sections of the longitudinal beam being slidable and gradually fixable by pegs.

[9] The descriptions provided by DE 19828037 and DE 29711998U present a more user-friendly apparatus. In this apparatus, the length of each cross-member is continuously adjustable, and it can be fixed by a screw, and the cross-members of the upper support means also comprise a fixed central and two adjustable side sections. Hence both the foot means and the size of the upper support means can be altered in this case. The apparatus presented in GB 933347 is similar: the foot means follows the cross-shaped arrangement, with one pair of legs, falling in the same line, being of a fixed design, and the other pair of legs being adjustable in longitudinal direction in two neighbored tubes. The upper support means comprises two cross-members and four longitudinal beams secured onto them, the latter comprising, outside the cross- members, two adjustable side sections as well. In the apparatus according to US 4,339,219, the longitudinal beam of the foot means is of a fixed design, with the central section of a cross-member being secured to each of the two ends, and the side sections are in the central sections continuously adjustable, without any fixing. The upper support means comprises a fixed frame, with adjustable appendages at both ends of the longitudinal beam and the cross-members.

[10] In addition to the adjustment of the various longitudinal beam elements, it is an important requirement that the upper support means be tiltable. Various solutions have evolved to ensure that, too.

[11] The simplest one is the solution whereby the upper support means is constructed on top of the telescoping mast with a hinge, so that it should be stable without any bolting in two positions, the horizontal and the substantially vertical one. Such solution is presented in US 4,339,219. In between the vertical and the horizontal positions, the upper support means holding the panel shall be held in position by the person doing the mounting.

[12] The apparatus described in US 7,048,258, where the upper support means is connected to the telescoping mast means by a simple hinge, is safer to use. The axis of the hinge is a threaded pin, onto which the upper support means can be fastened in the adjusted position with the clamping force of the nut wound onto it. The apparatus according to GB 2213189 and US 5,704,755 is designed with a similarly simple hinge. The solution under GB 2162815 is also similar, with the difference that, with the help

of two hinges which are perpendicular to one another or with one ball-and-socket joint, it can be set in any position in space.

[13] A more solid fixing is offered by the apparatus known from US 6,176,063, where two parallel semi-circular segment gears are fixed to the upper support means, pivotable around the horizontal axis mounted on top of the telescoping mast. The segment gear can be engaged in the configured position with a bolt actuated by a lever. An essentially similar apparatus is shown in FR 2741901, where a quarter of a circle is toothed only, or in the apparatus according to GB 933347, where a tooth groove occurs at every 45° only, or in the apparatus according to US 3,467,261, where a tooth groove occurs at every 90°.

[14] In terms of the operation principle, the solution presented in US 6,244,810 is also essentially similar. Here a fork is formed at the top of the telescoping mast, in which a disc is mounted with a horizontal axis. The upper support means is fixed to the disc. There are orientation bores in the disc, arranged along the same pitch circle and with the same pitch, into which a fixing peg guided in the fork can be fitted.

[15] However, while the arcuate row of teeth and the orientation bores allow to set the inclination of the upper support means gradually only, in the apparatus presented in DE 8312889U, this is done in a continuous manner. The upper support means of the apparatus is fixed to the top of the telescoping mast with a simple hinge, but a semicircular plate, too, is fastened onto the upper support means, which is on the same axis with the hinge. There is a semi-circular aperture in the plate, through which a threaded peg fixed in the mast extends. The semi-circular plate can be fixed to the mast with a nut. A similar design is shown in US 4,560,031 and US 5,322,403, whereas in the solution according to DE 8909821U two parallel elements provided with semi-circular aperture are fixed onto the upper support means from the two sides of the mast. The solutions shown in DE 19828037 and in DE 29711998U are also similar, but there the aperture is of a quarter of a circle only.

[16] A special embodiment is presented in FR 2552478. There the angle-adjusting apparatus comprises two parallel quarter-circle plates fastened to the telescoping mast. There are quarter-circle apertures in the plates, in which a tilting latch can be set into different angles. The upper support means is fastened to the telescoping mast with a simple hinge, and a detent protrudes from it in between the plates, which locks under the tilting latch.

Disclosure of Invention

Technical Problem

[17] As can be seen from the above overview, the elements of the foot means and especially of the upper support means are adjustable within a relatively limited range.

The elements usually comprise three sections, whereas the two side elements are slidable into the central one. Accordingly, the length of the central element corresponds to half of that of the entire element, and that of the side ones to one quarter of it. Since the other element attached perpendicularly to the given element is fastened to the middle of the central section of the latter, the outer end of the given element is adjustable in an interval corresponding to quarter to half length. Obviously, the only aim of this adjustment feature is to fit the apparatus to cover panels of different sizes. Such apparatus may be suitable for mounting ceiling cover panels, but the installation of the side-wall cover panels, for example, may also pose a problem. Moreover, the area above various unmovable objects on floor-level cannot be served with the current apparatus at all.

[18] As a matter of fact, neither can the apparatus be adjusted perfectly to the cover panels in every case. As can be seen from the scale relationships of the adjustable elements described above, the length of the cross-member of the upper support means can be reduced max. to its half. That is, if a cover panel which is shorter than that shall be mounted, the upper end of the cross-member will extend beyond the upper edge of the cover panel. If a cover panel of this kind is to be installed directly under the ceiling or the roof-beam, the upper end of the cross-member will get caught in these, that is, the cover panel will have to be lifted in position manually.

[19] In addition to the drawback implied by the limited adjustment interval, it is also difficult to load the apparatus. It is easier to move the cover panel if it stands on its edge, and it is easier to load it on the apparatus this way. In the available apparatuses, the cover panel usually has to be loaded in an position corresponding to the angle in which the upper support means is set. Given the fact that the own height of the telescoping mast is more than 1 m, for an upper support means in an inclined and even more in a horizontal position, the cover panel will definitely have to be lifted manually. It would be easier to load the cover panel if the upper support means could be set in a vertical or quasi- vertical position for this operation. Although this is feasible with those apparatuses where the angle-adjusting device can be set by grades, but these have the disadvantage that the actual installation angle of the cover panel cannot be set precisely.

[20] Finally, the apparatuses presented above raise a manufacturing problem as well.

The cross-sections of the elements slidable in one another are usually of a rectangular shape, and although the manner of fixing them is not described in detail anywhere, the relevant drawings warrant the conclusion that the elements are secured to one another by screws driven in the threaded bore of the element having the bigger cross-section. The drawings also show that the screw leans on the lateral surface of the element. With this arrangement, a stable fixing can only be achieved if the cross-sections of the

elements concerned fit perfectly to one another. This is not impossible to realize in itself, but it is more expensive than manufacturing based on commercially available standard-size hollow profiles. However, unfortunately, such materials cannot be applied, because the difference of the side-lengths of the consecutive standard-size profiles exceeds the thickness of the wall (e.g., the difference between the length of the. 40x40 and 35x35 profiles is 5 mm, while the wall thickness is only 1 - 3 mm, that is, there is a gap of 2 - 4 mm in between). Hence despite the clamping force exerted on the lateral surface, in the plane perpendicular to that, the possibility of splitting would prevail.

Technical Solution

[21] Therefore, the objective of the present invention is to design an apparatus the elements of which can be adjusted so as to allow to lift cover panels in place of application even above obstacles lying on the floor. The objective of the invention is, furthermore, to allow to install as low a cover panel as you may wish anywhere, irrespective of the fact that the smallest length of the cross-member of the upper support means is bigger than its height. Yet another objective is to make the upper support means tiltable for the purpose of loading the cover panel onto it back to vertical position even if it provided with an angle adjusting device which is not gradually fixable. Finally, it is the objective of the present invention that the apparatus concerned be such as can be manufactured cheaply, out of the standard-size hollow profiles available commercially.

[22] Several realizations have led to the creation of the apparatus meeting every one of the above requirements.

[23] Firstly, it has been realized that if the respective longitudinal beams of both the foot means and the upper support means can be positioned on at least one side of the cross-members at any place, up to the very end, and if, similarly, the telescoping mast, too, can be positioned on at least one side of the longitudinal beams of both the foot means and the upper support means at any place, up to the very end, the apparatus can be set so that the upper support means be positioned relative to the telescoping mast in one direction and the foot means in the other direction. In this case, the upper support means, as a jib, will extend over the obstacle lying on the floor.

[24] Furthermore, the invention is based on the recognition that if the clip underpinning the cover panel from below is not secured rigidly to the bottom end of the cross- member, but can be set at any place along its length, then, however low the cover panel, the clip can always be secured in such position as will ensure that the cross- member above should not extend beyond the cover panel.

[25] According to yet another recognition, in the angle-adjusting device, an adjusting element shall be inserted in between the hinge element of the vertical lifting means and

the hinge element of the upper support means. In between one of the hinge elements and the adjusting device, a continuous angle-adjustment feature shall be provided and, mechanically fully independently of that, at least a bolting feature shall be provided in between the other hinge element and the adjusting device, whereby one of the two can be turned from a bolted position to another position, and it can be bolted again if returned to the first.

[26] Finally, one realization offered a solution for the problem of economical manufacturing as well. Accordingly, it is possible to use the commercially available hollow profiles, if the line of action of the fixing is directed at the edge of the inner hollow profile, because in this case the inner hollow profile will be squeezed into the external one as one prism into another.

[27] The above make it quite obvious that the invention relates to several partial solutions to be used most preferably in combination in the apparatus for lifting plane elements, expediently wall and/or cover panels, but which can be realized independently of one another as well.

[28] One of our proposed solutions to the objective set above is based on an apparatus for lifting of plane elements, preferably wall and/or cover panels, said apparatus comprising foot means, vertical lifting means, upper support means carrying the plane element; in given case an angle-adjusting device inserted in between the vertical lifting means and the upper support means carrying the plane element; wherein said foot means as well as upper support means being made of one or more longitudinal beams and of cross-members being fastened to the longitudinal beams. The vertical lifting means and in given case the angle-adjusting device connected to it from above are fastened to the given longitudinal beam at both the foot means and the upper support means by a fixing unit to be set at one or several pre-defined point(s) along the section of at least its middle and its end; and/or the longitudinal beams are fixed to the given cross-member by a fixing unit to be set at one or several pre-defined point between at least the middle and the end of the given cross-member, and if a section suitable for the fixing of vertical lifting means or angle-adjusting-device is provided only on one side of the longitudinal beams, the section created for fixing the longitudinal beam of the upper support means and the section created for fixing the longitudinal beam of the foot means is on the opposite side relative to the vertical lifting means, and/or if a section suitable for fixing the longitudinal beam is provided on one side only of the cross-members, then the fixing section created for the cross-members of the upper support means and the section created for the fixing of the cross-members of the foot means are on the opposite side of the plane lying on the symmetry axis of the vertical lifting means and perpendicular with the cross-members.

[29] According to one advantageous embodiment of the proposed apparatus the fixing

unit in between vertical lifting means and in the given case the angle-adjusting device connected to it from above on the one hand and the longitudinal beams on the other includes a bracket, the surface of which is rigidly fixed to the vertical lifting means or in the given case the angle-adjusting device connected to it from above; the bracket is strung on the given longitudinal beam; in the side of the bracket, there is an aperture, into which a fixing element extends, which relies on the longitudinal beam.

[30] According to another advantageous embodiment of the proposed apparatus the fixing unit in between the longitudinal beams and the cross-members includes a bracket, the surface of which is rigidly fixed to the longitudinal beam; the bracket is strung on the given cross-member; in the side of the bracket, there is an aperture, into which a fixing element extends, which relies on the cross-member.

[31] It is furthermore advantageous according to the present proposal if the aperture in the bracket is a threaded bore, and the fixing element is a screw put into it.

[32] According to another advantageous embodiment of the proposed apparatus the longitudinal beam of the foot means and/or the upper support means comprises longitudinal beam elements slidable into one another, and the vertical lifting means and/or in the given case the angle-adjusting device connected to it from above is fastened to the longitudinal beam element having the bigger cross-section.

[33] It is furthermore advantageous according to the present proposal if the cross- members of the foot means and/or the upper support means comprise two cross-bar elements slidable into one another, and the given longitudinal beam is fastened to the cross-bearing element having the bigger cross-section.

[34] According to another advantageous embodiment of the proposed apparatus the cross-members of the upper support means are made as a single element, the cross- section of which is identical throughout their entire length and is suitable for fixing the longitudinal beam.

[35] The said objective has further been realised by an apparatus for lifting of plane elements, preferably wall and/or cover panels, said apparatus comprising foot means, vertical lifting means and upper support means carrying the plane element, whereas the vertical lifting means and the upper support means is connected by a horizontal axis. An adjusting element is pivotably mounted on the horizontal axis in addition to the hinge element of the vertical lifting means comprising the axis, and to the hinge element of the upper support means comprising the axis; an arcuate path known in itself and concentric with the axis is built on one of the adjusting element and the hinge elements while the other is provided with a fixing element which can be moved along the arcuate path and set at any place; a latch seat is created on one of the adjusting element and the other hinge element while the other is provided with a latch which can be fitted into the latch seat; and either there are more latch seats arranged at even pitch

along an arc concentric with the axis, or there is only one single latch seat and each of the hinge elements is provided with one cushion surface, which are at the greatest distance from one another when the upper support means is in horizontal position, while if the upper support means is in quasi- vertical position, they butt on one another, in which case the angle of the plane of the upper support means to the vertical is an angle of 0° to 15°.

[36] According to one advantageous embodiment of the proposed apparatus the adjusting element is located between the two hinge elements.

[37] It is furthermore advantageous according to the present proposal if the arcuate path is an arcuate aperture, and the fixing element is a screw penetrating through the aperture.

[38] It is furthermore advantageous according to the present proposal if the latch seat is a bore, and the latch is a pin fitting into said bore.

[39] The said objective has further been realised by an arrangement for fixing in longitudinal direction two elements of a polygonal cross-section which are slidable in one another, wherein the two neighboring external surfaces of the inner element are propped up on the two neighboring inner surfaces of the external element; an aperture is made in the wall of external element diagonally opposite the common edge of said two underpinning surfaces, through which a fixing element extends into the space of the external element; the fixing element in the fixed state of the internal element leans on the surface opposite the common edge of the two underpinning surfaces of the inner element, and the line of action of the locking force of the fixing element includes an angle of less than 90° with both underpinning surfaces.

[40] According to one advantageous embodiment of the proposed arrangement a bracket is placed on the external element above the aperture created for the fixing element, in which bracket an aperture congruent with the aperture of the external element is created, and the fixing element extends through both apertures.

[41] According to another advantageous embodiment of the proposed arrangement the aperture created for fixing element in the wall of the external element or in the bracket is a threaded bore, and the fixing element is a screw put into it.

[42] It is furthermore advantageous according to the present proposal if the external element is a hollow profile, to the wall of which, around the aperture created for the fixing element, a projection is fixed from the outside, in which a threaded bore is created.

[43] It is furthermore advantageous according to the present proposal if the bracket is a hollow profile, to the wall of which, around the aperture created for the fixing element, a projection is fixed from the outside, in which a threaded bore is created.

[44] According to another advantageous embodiment of the proposed arrangement the

external element and in the given case the bracket is a hollow profile with a rectangular cross-section, where the aperture created for the fixing element is made at one of the edges.

[45] One of our proposed solutions to the objective set above is based on an apparatus for lifting of plane elements, preferably wall and/or cover panels, said apparatus comprising foot means, vertical lifting means and upper support means carrying the plane element, whereas the upper support means is made of longitudinal beams and cross-members fixed to said longitudinal beams, and the cross-members are provided with a clip each, propping up the edge of the plane element at least from below, and the clip is fixed to the given cross-member by a fixing unit which can be set to any one or one of several pre-defined points on the cross-member.

[46] According to one advantageous embodiment of the proposed apparatus the fixing unit includes a bracket, which is strung on the cross-member; the clip is prepared on the external surface of the bracket; and in the bracket, in addition to its surface including the clip there is an aperture, into which a fixing element extends, which leans on the cross-member.

[47] It is furthermore advantageous according to the present proposal if the aperture in the bracket is a threaded bore, and the fixing element is a screw put into it.

[48] One of our proposed solutions to the objective set above is based on an apparatus for lifting of plane elements, preferably wall and/or cover panels, said apparatus comprising foot means, vertical lifting means and upper support means carrying the plane element, whereas the upper support means is made of longitudinal beams and cross-members fixed to said longitudinal beams, and said cross-members are provided with a clip each, propping up the edge of the plane element at least from below. Said clips being made at the end of the cross-member itself, or on a separate fixing unit which can be secured to the cross-member, and the clip is an L-shaped element, the plane of which lies beside the cross-member or the fixing unit when apparatus is in use, and the plane of which is parallel with the cross-member and perpendicular to the plane of the upper support means, the longer leg of the clip is fixed on the cross- member or the fixing unit and can be lowered around a hinge and is held up by a spring, and the shorter leg of the clip extends in normal position above the plane of the upper support means.

[49] According to one advantageous embodiment of the proposed apparatus there is a buffer defining the normal position above the longer leg of the clip.

[50] According to another advantageous embodiment of the proposed apparatus the hinge and the spring are made as a single flexible unit.

[51] It is furthermore advantageous according to the present proposal if an L-shaped element is placed on each of the two sides of the cross-member or the fixing unit, and

the free ends of the shorter legs of the L-shaped elements are linked to one another.

Advantageous Effects [52] The apparatus can be set within big intervals, and hence the zone above any obstacles on the floor can also be served well. [53] A cover panel as low as desired can be installed into any environment, that is, also in places delimited from above. [54] The cover panel to be installed can easily be placed on the apparatus, because the angle of the upper support means can be reproduced continuously after having been set once. This is advantageous, for example, when a longer roof structure must be covered from below, and several cover panels are to be put side by side or occasionally one above the other, at the same angle. [55] Thanks to the fixing arrangement proposed by the invention, there is no need to provide for the guiding of the elements which can be slid in one another, and hence cheaper and more easily accessible materials can be used for manufacturing.

Description of Drawings [56] The invention will be introduced in more detail on the basis of a specific exemplary embodiment, with reference to the following drawings, whereas [57] Figure 1 is a schematic perspective view of an apparatus according to the invention,

[58] Figure 2 is a partial side view in direction I of the apparatus of the Fig 1,

[59] Figure 3 is a cross-sectional view of the apparatus of the Fig 1 along a line H-H indicated in Figure 2, [60] Figure 4 shows foot means of the apparatus in partial overview in direction in of

Fig l,

[61] Figure 5 is a longitudinal section along a line IV-IV indicated in Fig 4,

[62] Figure 6 is a longitudinal vertical sectional view of the vertical lifting means of the apparatus along a line V-(VIjVII)-V indicated in Fig 1 (*),

[63] Figure 7 is a cross-sectional view along a line VI-VI indicated in Fig 6,

[64] Figure 8. is a partial longitudinal view along a line VII-VII indicated in Fig 6,

[65] Figure 9. is a partial side view of the upper support means of the apparatus in direction VIII indicated in Fig 1, [66] Figure 10. is a cross-sectional view of the apparatus of the Fig 1 along a line IX-IX indicated in Fig 9, [67] Figure 11. is a side view of the angle-adjusting device of the apparatus in direction

X indicated in Fig 1,

[68] Figure 12 shows a graded section along a line XI-XII indicated in Fig 1,

[69] Figures 13 and 14 show schematically the apparatus in two special positions, in

front and side view, respectively, and

[70] Figures 15 A to C show the angle-adjusting device in lateral view, in three different positions.

[71] (* The position of intersecting planes VI and VII is not indicated in Fig 1, because it cannot be depicted there, but it will be possible to identify it exactly on the basis of the description of the Figure 6.)

Best Mode

[72] Figure 1 is a perspective view of an embodiment of the apparatus according to the invention carried out in practice. With the help of what is generally indicated as apparatus 1, wall or cover panels can be lifted to any position under any environmental condition.

[73] The design of apparatus 1 has not been motivated exclusively by the criterion of offering the best possible utilization properties, but also by that of easy transportation. Therefore, apparatus 1 has been made of such parts and elements as can be assembled and disassembled easily, and require the least space in disassembled state. Therefore, apparatus 1 includes all the structural partial solutions which, on the one hand, have proved advantageous in the case of similar prior art apparatuses and, on the other, are provided by the present invention.

[74] In addition to practical utilization and easy transportation, another important criterion was for apparatus 1 to be manufacturable easily and cheaply. One method for that is to use such materials, to the extent of the possible, as can be acquired in the standard commercial sizes. Therefore, the structural parts of apparatus 1 have been made of hollow profiles made of steel, having a rectangular cross-section, and chosen from among the commercially available standard sizes. As will be shown by the description below, therefore, such partial solutions had to be used, too, for apparatus 1 as would not have been necessary otherwise for the basic functions.

[75] As can be seen in Figure 1, apparatus 1 can be divided, in the manner known in the art, into three main structural units, namely foot means 2, a vertical lifting means 25 and an upper support means 49.

[76] Foot means 2 consists of one longitudinal beam 3 and two cross-members 13.

[77] Longitudinal beam 3 comprises two longitudinal beam elements 4 and 5, the cross- section of which is selected so that longitudinal beam element 5 should fit into longitudinal beam element 4. This not only ensures that the length of longitudinal beam 3 be adjustable, but also allows to disassemble it completely for transporting purposes.

[78] A fixing unit 12 is made at that end, the outermost part, of longitudinal beam element 4 having the bigger cross-section, from which longitudinal beam element 5, the one with the smaller cross-section, is slid in. After mounting and adjustment, longitudinal beam elements 4 and 5 can be fastened together rigidly with the help of the

fixing unit 12. Fixing unit 12 will be presented in more detail with reference to Figures 2 and 3.

[79] As can be seen clearly in Figure 3, there is a relatively big gap between the inner surface of longitudinal beam element 4 and the outer surface of longitudinal beam element 5. This is attributable, as mentioned earlier, to the fact that the difference in the respective lengths of hollow profiles of consecutive standard sizes is bigger than the thickness of the wall.

[80] Yet another construction problem shall be taken into account when designing fi xing unit 12. Vertical lifting means 25 is fixed to longitudinal beam 3 - in a manner to be presented in more detail below - by a part through which longitudinal beam 3, or more precisely its longitudinal beam element 4, shall be slipped upon the assembly of apparatus 1. Therefore, longitudinal beam element 4 shall have no outward projecting member on its surface, at least at one end of it.

[81] Fixing unit 12 had to be designed so as to ensure that longitudinal beam elements 4 and 5 should not move in longitudinal direction and, moreover, that they should not waggle either, despite the gap. Therefore, fixing is ensured by making the two adjoining surfaces 5a and 5b of longitudinal beam element 5 lean against on the two adjoining inner surfaces 4a and 4b of longitudinal beam element 4.

[82] In the wall of longitudinal beam element 4, at its edge opposite the common edge of surfaces 4a and 4b, an aperture 7 is formed. There is a bracket 6 mounted on longitudinal beam element 4, above aperture 7, which in the given case is also cut to measure from a steel hollow profile having a rectangular cross-section.

[83] Within bracket 6, at its edge located above aperture 7, an aperture 8 is formed. A projection 9 is welded on the bracket 6, above the aperture 8, so that its axis lies in the diagonal plane Sl passing through the common edge of surfaces 5a and 5b of the longitudinal beam element 5, and it is perpendicular to axis Tl of the longitudinal beam element 5.

[84] In the projection 9, there is a through-bore 10, which is threaded, together with the aperture 8. A locking butterfly screw is driven in aperture 7 and through-bore 10 as a fixing element 11, which extends through the aperture 7 in the longitudinal beam element 4, and leans on the edge facing the common edge of the surfaces 5a and 5b of the longitudinal beam element 5.

[85] Thanks to the above design, upon fixing, the two inner surfaces 6a and 6b of bracket 6 flanking its edge opposite fixing element 11 will lean on the outer surfaces 4a' and 4b', in identical position with inner surfaces 4a and 4b, of the longitudinal beam element 4. Consequently, the fixing element 11 exerts a clamping force on the longitudinal beam element 5, squeezing the longitudinal beam element 5 into the longitudinal beam element 4 and, at the same time, squeezing the longitudinal beam

element 4 into the bracket 6. This way, longitudinal beam element 4, longitudinal beam element 5 and bracket 6 are rigidly fixed to one another.

[86] As can be seen from the above description, fixing unit 12 is provided in combination by bracket 6, projection 9, aperture 8, through-bore 10, fixing element 11 and aperture 7 created in the given structural element, in the given case in longitudinal beam element 4.

[87] The use of bracket 6 allows to pull out fixing unit 12 from longitudinal beam element 4 if fixing element 11 is unscrewed. Hence this end of longitudinal beam element 4 will remain empty.

[88] To each of the opposite, in other words outer, ends of longitudinal beam elements 4 and 5, a cross-member 13 is fastened with a fixing unit 17. Cross-members 13 comprise two elements themselves, cross-bearing elements 14 and 15, the cross sections of which are chosen so that cross-bearing element 15 should fit into cross- bearing element 14. (Although not necessarily justified in terms of statics, the same two profile sizes can be used for longitudinal beam 3 and cross-member 13, and even for upper support means 49, to be described later.)

[89] Fixing unit 17 will be presented in more detail with reference to Figures 4 and 5.

Its essential element is a bracket 16, welded to the end of longitudinal beam elements 4 and 5, respectively, so that their axiss are parallel with one another and perpendicular to the axis of the longitudinal beam 3. Cross-bearing elements 14 are put into these.

[90] As illustrated in Figure 5, there is a relatively wide gap between the inner surface of the bracket 16 and the outer surface of the cross-bearing element 14, too, and, therefore, fixing unit 17 is also made in such manner as will ensure that, despite the gap, cross-bearing element 14 fixed in longitudinal direction should not waggle in the bracket 16. Therefore, for the purpose of fixing, in this case, the two adjoining external surfaces 14a and 14b of the cross-bearing element 14 are propped up against the adjoining inner surfaces 16a and 16b of the bracket 16.

[91] In the wall of the bracket 16, at its edge facing the common edge of surfaces 16a and 16b, an aperture 7 is formed, above which a projection 9 is welded from the outside. The axis of projection 9 lies in diagonal plane S2 passing through the common edge of surfaces 14a and 14b of the cross-bearing element 14, and it is perpendicular to axis T2 of the cross-bearing element 14.

[92] Projection 9 is provided in the manner identical with that described above with a through-bore 10. through-bore 10 and aperture 7 are threaded. Here again a locking butterfly screw is driven into aperture 7 and through-bore 10 as fixing element 11, which extends through aperture 7 to the inside of bracket 16, to lean on the edge opposite the common edge of surfaces 14a and 14b of the cross-bearing element 14.

[93] Upon securing the fixing unit 17, the fixing element 11 clamps the cross-bearing

element 14 into the bracket 16 by the clamping force it exerts on the cross-member 14, creating a rigid fixing thereby.

[94] In this case, the fixing unit 17 is created in combination by bracket 16, aperture 7, projection 9, through-bore 10 and fixing element 11.

[95] A comparison of the longitudinal beam 3 and the cross-members 13 based on

Figure 1 allows to establish that no part similar to the fixing unit 12 on the longitudinal beam 3 is made on the cross-members 13. Experience with the actually manufactured apparatus 1 suggested that the own weigh of the apparatus 1 is big enough for the cross-bearing element 14 and the cross-member 15 put into one another to press against one another to the extent of being in rigid contact without special fixing as well. Hence rigid contact between the cross-bearing element 14 and the cross-bearing element 15 can be terminated by the simple lifting of the cross-member 13, and both can be easily adjusted relative to one another. Of course, if it seems necessary, a fixing unit 12 can be made easily here, too.

[96] Under the outer ends of cross-bearing element 14 and 15, respectively, a self- aligning roller 18 is installed. Two of the four rollers 18 are equipped with a locking brake 19 as well.

[97] Vertical lifting means 25 is fixed on the longitudinal beam 3 by fixing unit 23. Theoretically, the fixing unit 23 could be created on the vertical lifting means 25 itself, but in the interest of better assembly properties, the fixing unit 23 is created on a mast holder end piece 20, and fixing unit 24 for vertical lifting means 25 is also created there.

[98] Mast holder end piece 20 is a T-shaped element turned downwards, the leg and shoulder of which is made of steel hollow profiles of rectangular cross-section, fixed together by welding.

[99] The head part of mast holder end piece 20 is designed as a fixing unit 23. Accordingly, functionally, the head part of mast holder end piece 20 is a bracket 22.

[100] In terms of design, the fixing unit 23 is perfectly identical with the fixing unit 17.

Bracket 22 is provided, in the arrangement presented for the fixing unit 17, with the elements presented there, that is, aperture 7, projection 9, through-bore 10, and fixing element 11 designed as butterfly screw. In the interest of more secure fixing, two sets of the above-mentioned elements are made on bracket 22, on the two sides of the leg part of mast holder end piece 20.

[101] Upon securing, bracket 22 is pulled on the longitudinal beam element 4 of the longitudinal beam 3. Through the clamping force exerted on the longitudinal beam element 4, fixing element 11 squeezes the longitudinal beam element 4 into bracket 22, creating a rigid fixing between them.

[102] The leg part of the mast holder end piece 20 is designed in a similar way as the

fixing unit 24. Here the bracket 21 is formed by the leg part of mast holder end piece 20, which is also provided with the elements presented above in the arrangement presented above, that is, with aperture 7, projection 9, through-bore 10 and fixing element 11 designed as a butterfly screw. In the interest of more secure fixing, two sets of said elements are made on bracket 21, too.

[103] The essential element of vertical lifting means 25 - shown independently, too, in

Figure 6 - is a telescoping mast 26, which may include one or several steps depending on the envisaged maximum elevation height. In the vertical lifting means 25 shown in Figure 6, the telescoping mast 26 includes of two stages, that is, it is made of mast elements 26a, 26b and 26c.

[104] (As mentioned already in the list of Figures, Figure 6 is actually to be considered a graded section, including, in addition to the section provided by cutting plane V on the vertical axis, a partial section provided by a cutting plane VI and one provided by VII, too. The place of partial sections VI and VII, respectively, in Figure 6, is indicated by dotted lines - the standard marking for section borderlines -, and Figure 8 shows where cutting plane VI is located relative to the vertical axis. The position of cutting plane VIE is similar, as indicated in Figure 8 by the marking VI(VII)).

[105] As the bottom end of the lowermost element 26a of the telescopic mast 26 is fixed in bracket 21 of mast holder end piece 20, obviously, the inner size of the hollow profile of which bracket 21 is made is adapted to the outer size of the mast element 26a.

[106] Mast elements 26a, 26b, 26c are also made of hollow profiles which can be inserted in one another. Given the fact that, for the telescoping mast 26, as a result of the movement of mast elements 26a, 26b, 26c, the fixing construction presented above cannot eliminate the gap due to the use of standard-size hollow profiles, but neither can an inaccurate fitting be allowed due to the stability requirement, the upper ends of the mast elements 26a and 26b, respectively, and the bottom ends of mast elements 26b and 26c, respectively, are provided with distance holder sliding inserts 27 at their respective edges, as can be seen in Figures 6 and 7, respectively.

[107] Raising/lowering the mast elements 26b and 26c is done, in the manner known in the art, with the help of a cable 28. As can be seen in Figure 6, at the bottom of the mast element 26b there is a pulley 29 and at the bottom of the mast element 26c a pulley 30 mounted with a horizontal axis. On the mast element 26a, at its upper end, on the outside, there is a pulley 31, and on the mast element 26b, at its upper end, on the outside, a pulley 32 mounted with horizontal axis. The symmetry plane of the grooves of pulleys 29, 30, 31 and 32 lies in the same plane. Pulleys 31 and 32 are placed on the two opposite sides of the telescoping mast 26.

[108] The cross-section of the mast elements 26a, 26b, 26c and, accordingly, the

thickness of the distance holder sliding insert 27, is chosen so as to allow the aperture formed by them to house the cable 28. As can be seen in Figure 6, the central diameter of the grooves of the pulleys 29 and 30, respectively, is the sum of the size of the mast elements 26b and 26, respectively, parallel with the groove of pulleys 29 and 30, respectively, on the one hand, and of the thickness taken once of distance holder sliding insert 27 on the other.

[109] (One more criterion was taken into account for the embodiment of the invention carried out in practice. The difference of the external radius of the pulley 29 and of half of the inner size of the mast element 26a, and the difference of the external radius of the pulley 30 and half of the inner size of the mast element 26b, respectively, is smaller than the diameter of the cable 28. Hence even if cable 28 loosens - e.g. in case of the transportation of the apparatus -, it will not be dislocated from the respective grooves of the pulleys 29 or 30.)

[110] No such requirements exist for the diameters of the pulleys 31 and 32, respectively, except that they should be adapted to the permissible bending radius of the cable 28. Since the ideal central diameter of the groove of pulley 32 would be identical with the sum of the wall thickness of the mast element 26b and of the thickness of the distance holder sliding insert 27, but the permissible bending radius of the cable 28 certainly exceeds that, in the wall of the mast element 26a, in the plane defined by the grooves of pulleys 29, 30, 31 and 32, a slot 33 is being formed, which is wide enough to house the cable 28.

[Ill] (In this case, the displacement of cable 28 is prevented by the fact that the distance between the outer surface of the pulley 31 and the outer surface of the mast element 26b, and the distance between the outer surface of the pulley 32 and the outer surface of the mast element 26c, respectively, is smaller than the diameter of the cable 28.)

[112] As indicated, albeit symbolically only, in Figure 6, on the side of the mast element

26a where the pulley 31 is mounted, a winch 34 the axis of which is parallel with the axis of the pulley, is installed (the contour drawn in dotted line is meant to indicate that the representation is not true to scale, because there is not enough space for that in the drawing). One end of the cable 28 is fixed to cable drum 35, and then led above through pulley 31, below through pulley 29 and then again above through pulley 32, below through pulley 30 and, finally, its other end is fixed with locking screw 37 to the upper end of mast element 26b.

[113] Cable drum 35 of winch 34 can be turned by a lever 36 through a cogwheel transmission and can be bolted by a latching device. Instead of lever 36, it is possible to use an electrical driving mechanism, although the load is so small that it is quite easy to operate the winch 34 manually, too.

[114] The telescoping mast 26 is provided with a safety device 39, too, which prevents

the fall of mast elements 26b and 26c, respectively, should the cable 28 break. Figure 8 shows safety device 39 arranged in the mast element 26b.

[115] Axis 38 of the pulley 29 is mounted in bracket 40. Both ends of the axis 38 are guided by vertical elongated bores 41, too, formed in the wall of mast element 26b. Above the bracket 40, a brake wedge 42 formed as a two-armed lever is placed, so that its plane is perpendicular to that of the groove of pulley 29. Axis 44 of the brake wedge

42 is embedded in the mast element 26b.

[116] The outward end of the brake wedge 42 is a brake surface 43, and on its inner end, the bracket 40 is hung by a link 46. Brake surface 43 is formed eccentrically relative to the axis 44 of the brake wedge 42, so that the distance of the brake surface 43 measured from the axis 44 increases downwards. In the wall of the mast element 26b, a vertical window 45 is made for the brake wedge 42.

[117] In mast element 26b, above brake wedge 42, a horizontal pin 47 is placed. Between pin 47 and brake wedge 42, a tension spring 48 is inserted, the force of which is smaller as a matter of course than the load borne by pulley 29. In addition, spin 47 has a movement-limiting function as well: it prevents that, in lowered state, the mast element 26c should slide onto brake wedge 42 in the mast element 26b. (It is no accident that there is no separate fixing at either axis 38 or pin 47, as they are of such length that the mast element 26a prevents that they should drop out.)

[118] Given the fact that the safety device 39 is not part of the present invention, suffice it to note briefly the following regarding its operation. During raising, the cable 28 raises the pulley 29 relative to the mast element 26b, said pulley holding, through link 46 - against spring 48 - brake wedge 42 in such position as prevents that brake surface

43 should reach the inner surface of mast element 26a. If cable 28 breaks, the force keeping pulley 29 in raised position decreases, and the spring 48 pushes the pulley 29 down, tilting thereby the brake wedge 42. Consequently, the brake surface 43 is pressed to the inner surface of the mast element 26a, fixing thereby the mast elements 26a and 26b to one another.

[119] As shown in Figure 8, the outer wall of the bracket 40 leans on the inner surface of the mast element 26b, and the pulley 29 is of such width as allows to fill the space avai lable to it. This, too, aims at preventing that a loosening cable 28 should get caught in between the pulley 29 and the inner surface of the mast element 26b. If the pulley 29 is made of a material characterized by high specific weight, its weight will complement the effect of the spring 48.

[120] Safety device 39 arranged in the mast element 26c differs from the one presented above exclusively in that it is constructed with a pulley 30 instead of a pulley 29.

[121] At the upper end of the mast element 26c, a fixing unit 12 is formed. Angle- adjusting device 59, to be described below, can be secured to the top of the telescoping

mast 26 by the fixing unit 12.

[122] Upper support means 49 is made in a manner essentially identical with that of foot means 2, out of the hollow profiles used there, too, and it comprises a longitudinal beam 50 and two cross-members 53. Longitudinal beam 50 is made up of a longitudinal beam element 51 and a longitudinal beam element 52 which is slidable into it. Cross-member 53 is made of a single piece.

[123] At that end of the longitudinal beam element 51 having the bigger cross-section where longitudinal beam element 52 is placed into it, a fixing unit 12 is formed. This ensures, in the known manner, the fixing together of longitudinal beam elements 51 and 52.

[124] At the outer end of the longitudinal beam elements 51 and 52, respectively, a fixing unit 17 is formed, which is identical with the fixing unit 17 described for foot means 2. The bracket 16 of the fixing unit 17 is welded onto the end of the longitudinal beam elements 51 and 52, respectively. Their axes are parallel with one another, but perpendicular with the axis of the longitudinal beam 50. Cross-members 53 are put into these.

[125] A clip 54 is fastened on the cross-member 53 - in the manner shown in Figures 1 and 9 and 10, respectively - with the help of a fixing unit 56.

[126] Similarly to the fixing unit 12, fixing unit 56, too, is made with a bracket 55, which is a short piece of a hollow profile. The two adjoining inner surfaces 55a and 55b of the bracket 55 lean on the two adjoining external surfaces 53a and 53b of the cross- member 53. In the wall of the bracket 55, at its edge lying opposite the common edge of surfaces 55a and 55b, an aperture 7 is formed, above which a projection 9 with a through-bore 10 is welded from the outside. The known butterfly screw is driven into the thread formed in the aperture 7 and the through-bore 10, extending into the inside of bracket 55, leaning at its edge opposite the common edge of surfaces 53a and 53b of cross-member 53, pressing bracket 55 on cross-bearing element 53. Hence in this case fixing unit 56 is made up of bracket 55, aperture 7, projection 9, through-bore 10 and fixing element 11.

[127] Clip 54 is a form blended of a piece of spring steel wire, comprising two L-shaped parts in parallel planes with one another and a connecting part connecting to ends of the shorter legs of the two L-shaped forms. The longer leg of the L-shaped forms is much longer than the bracket 55. Each of the free ends of these longer legs is fixed to the side of the bracket 55 with a clamp. During utilization, the bracket 55 is laced on the cross-member 53 so that the plane of the two parallel L-shaped parts of the clip 54 are perpendicular with the plane of upper support means 49, and the section connecting the shorter legs of the L-shaped forms is placed at least in such height above the cross- member 53 as the thickness of the cover panel to be fitted.

[128] Clip 54 formed this way underpins the cover panel securely, but when the latter is fitted to its place, the clip 54 gets stuck in the adjoining cover panels mounted already, and it can bend down around the gripping point at the end of the clamp fixing it onto the bracket 55 as around a quasi-hinge point, and hence it does not hinder the perfect installation of the cover panel. As can be seen, the longer leg of the L-shaped forms merges two functions. On the one hand, it functions as a hinge, around which clip 54 will tilt down, and on the other as a spring, which will return it to neutral position in unloaded state.

[129] As the cross-member 53 is made of single piece, the bracket 55 can be pushed anywhere upon it. Hence the clip 54 can be set at any place along the cross-member 53. Otherwise, if necessary, a clip 54 can be placed on the cross-member 53 from its other end as well.

[130] Vertical lifting means 25 and upper support means 49 are linked by angle-adjusting device 59, which will be presented in more detail with the help of Figures 11 and 12.

[131] The angle-adjusting device 59 comprises, essentially, three discs, arranged side by side on a common horizontal axis 60. Axis 60 is a threaded pin with a head at one end, whereas the other end is closed with a nut 61. Nut 61 is of the self-securing kind to facilitate assembly.

[132] To one of the side discs, a socket piece 62 is fastened in radial direction. The socket piece 62 is a hollow profile piece fitting into the upper end of the mast element 26c of the telescoping mast 26. Its fastening is ensured by the fixing unit 12 arranged on the mast element 26c. The disc on the side together with the socket piece 62 provide a hinge element 63 of the vertical lifting means 25.

[133] A bracket 66 is fastened to the edge of the other side disc, and the two together provide a hinge element 65 of the upper support means 49. The axis of the bracket 66 is parallel with the axis 60.

[134] By the way, the inner size of the bracket 66 made of a hollow profile fits to the longitudinal beam element 51, having the bigger cross section, of the longitudinal beam 50 of the upper support means 49. Bracket 66 is one of the elements of the fixing unit 67. The design of the fixing unit 67 is identical with that of the fixing unit 17 and, accordingly, an aperture 7 is formed in one of its edges, above which a projection 9 with a through-bore 10 is welded from the outside. The known butterfly screw is driven into the thread formed in the aperture 7 and the through-bore 10 as a fixing element 11, which upon fixing will extent into the inside of the bracket 66, to lean in the edge of the longitudinal beam element 51 of the longitudinal beam 50.

[135] The central disc is the adjusting element 64 of angle-adjusting device 59.

[136] In the disc of the hinge element 63, a quarter-circle-length arcuate path 68 is made, which is concentric with the axis 60, and which is designed as an arcuate aperture. A

fixing element 69 extends through arcuate path 68. Fixing element 69 is designed as a threaded pin, its end opposite to the thread being secured into adjusting element 64. A locking nut 70 provided with a handle to allow easier handling is screwed onto the fixing element 69 from the other side of the adjusting element 63.

[137] Within the adjusting element 64, in its front surface on the side of the disc of the hinge element 65, a latch seat 71 is formed, which is a cone-shaped bore narrowing towards the inside. A latch 72 fits into latch seat 71. Latch 72 is a conical pin, guided in the bore of the disc in the hinge element 65. On the other side of the disc of hinge element 65, a spring housing 73 is constructed, into which a spring 74 is placed, which holds a latch 72 in bolt nest 71. A handle 75 is formed at the outer end of the latch 72.

[138] On the outer side of the disc of the hinge element 63, a buffer 76 is mounted.

Buffer 76 extends into the path of movement of the bracket 66 of the hinge element 65. The opposite surfaces of the buffer 76 and the bracket 66 are cushion surfaces 77 and 78, respectively. Cushion surfaces 77, 78 are arranged so that if they butt on one another, plane F of upper support means 49 is at an angle φ of 10° to the vertical, bending backward relative to the vertical.

[139] At its end on the side of the hinge element 65, a bracket 79 is secured to the bracket

66, so that its geometric axis passes through the geometric axis of the angle-adjusting device 59. Bracket 79 is a hollow profile having a smaller cross-section, and it is an element of fixing unit 80. The design of the fixing unit 80 is identical with that of fixing unit 17, that is, it is provided with aperture 7 in its edge, as well as a projection 9 including through-bore 10 welded above it from the outside, and a fixing element 11 designed as locking butterfly screw, which, upon fixing, will extend into bracket 79 and lean on leg 81 formed out of a hollow profile, placed into bracket 79.

[140] Apparatus 1 described above is assembled and applied in the following manner.

[141] For the purpose of transportation, apparatus 1 is dismounted as follows.

[142] At foot means 2, longitudinal beam elements 4 and 5 and the two cross-bearing elements 14 and 15 are pulled out of one another. Fixing unit 12 and mast holder end piece 20 are removed from the longitudinal beam element 4. The two cross-bearing elements 13 are removed from the fixing unit 17 of the longitudinal beam elements 4 and 5.

[143] The mast element 26a of the telescoping mast 26 is taken out of the mast holder end piece 20, and the angle-adjusting device 59 is dismounted from the top of the mast element 26c. As the telescoping mast 26 is a single unit (its assembly requires more expertise than the assembly of apparatus 1), the fixing unit 12 located on the top of the mast element 26c is loosened only to the extent of allowing to pull out the socket piece 62.

[144] The longitudinal beam elements 51 and 52 are pulled out of one another at the

upper support means 49, too; the fixing unit 12 is removed of the longitudinal beam element 51, and the longitudinal beam element 51 is pulled out of the fixing unit 67 of the angle-adjusting device 59. The two cross- beams 53 are pulled out of the respective fixing units 17 of the longitudinal beam elements 51 and 52. If there is only one clip 54 on each of the cross-members 53, that will not be loosened, but if there are two, one is also dismounted, as a matter of course.

[145] In disassembled state, the apparatus 1 is placed in a carrier bag designed for this purpose.

[146] It is relatively easy to understand the assembly procedure of apparatus 1 on the basis of the disassembled state.

[147] It is worth starting with the assembly of foot means 2. For that, the fixing unit 23 of the mast holder end piece 20 as well the fixing unit 12 must be pulled on the longitudinal beam element 4, and then the longitudinal beam element 5 can be slid in. For the assembly, it is worth securing temporarily both the fixing unit 12 and the fixing unit 23. Of course, during the assembly of the longitudinal beam 3, care shall be taken that the axiss of the fixing units 17 at its two ends should be parallel with one another and perpendicular with the axis of the fixing unit 24 of the mast holder end piece 20. Subsequently, the cross-bearing elements 14 can be placed in the fixing units 17, and these, too, can be secured temporarily, and finally the cross-bearing elements 15 can be slid into the cross-bearing elements 14. Of course, attention shall be paid in this case, too, to placing the rollers 18 on the bottom side.

[148] After that, it is expedient to put the mast element 26a of the telescoping mast 26 into the fixing unit 24 of the mast holder end piece 20, and to secure it for good and then to place it into the mast element 26c, and to secure definitively by the fixing unit 12 the socket piece 62 of the angle-adjusting device 59.

[149] Finally, the longitudinal beam element 51 of the upper support means 49 shall be strung into the fixing unit 67 of the angle-adjusting device 59, the fixing unit 12 shall be placed onto it, and the longitudinal beam element 52 shall be slid into it. Fixing unit 12 as well as the fixing unit 67 shall be secured temporarily. Here again attention shall be paid to the adequate arrangement of the longitudinal beam elements 51 and 52. Therefore, it is best to carry out this assembly phase so that the fixing unit 67 of the angle-adjusting device 59 should be set in the upper position - in the manner to be described below. In this case, the axis of the fixing units 17 at the respective outer ends of the longitudinal beam elements 51 and 52 shall be in horizontal position. Subsequently, the cross-members 53 shall be placed into the fixing units 17, and these, too, shall be secured temporarily. If clips 54 are needed at both ends of the cross-members 53, then these, too, can be mounted now.

[150] Four criteria are to be taken into account for the adjusting of apparatus 1 : the length

of the cover panel 82, e.g. plasterboard to be mounted; its position in mounted state in the given coverage; its angle to the horizontal; and the place where the apparatus 1 shall work.

[151] Taking into account the width and length of the cover panel 82 requires an obvious operation. By loosening the fixing unit 12 and moving the longitudinal beam elements 51 and 52 outward or inward and then by securing the fixing unit 12, the distance between the two cross-members 53 can be set to the desired size.

[152] The length of cross-members 53 was defined so as to match the biggest-size commercially available cover panel 82. (It is not worth making an adjustable embodiment because cover panels 82 of a smaller size can always be put up on the longer cross- members 53.)

[153] Hence the length of cross-members 53 cannot be altered.

[154] The apparatus 1 described above is designed for such installation of cover panels

82 where their longer side is parallel with the longitudinal beam 50. It may happen that the cover panel 82 should be mounted in an unusual manner, so that its longer sides be parallel with the cross-members 53. In this case, the cross-members 53 of the size defined above would not provide stable underpinning. Therefore, the set can be supplemented with two such appendages 57 as can be pulled into the cross-members 53 in the manner indicated by dotted lines in Figure 1. Appendages 57, too, are made of hollow profiles and are provided with one buffer 58 each, which prevents that they should slip through cross-members 53. The length of the appendages 57 above the buffer 58 is chosen so that their length in combination with the cross-member 53 should match the length of the cover panel 82.

[155] As for the position occupied by the cover panel 82 in the given coverage, one must consider its height between the floor-level and the ceiling or roof.

[156] The lowest operating height of the apparatus 1 can be ensured in case of vertical coverage by lowering the telescoping mast 26 fully, and lowering the cross-members 53, too, so that their upper end is secured in the fixing units 17, and their clip 54 is at their bottom end. (For a horizontal cladding, the lowest operation height can be achieved, obviously, by fully lowering the telescoping mast 26.)

[157] If the cover panel 82 shall be mounted directly below the ceiling or the roof-beam, the clip 54 must be positioned on the cross-members 53 so that the cover panel 82 should reach over their upper end.

[158] If the apparatus 1 is in normal position, plane F of the upper support means 49 is in the position indicated in Figure 11, that is, the angle φ of its plane F relative to the vertical is bent backwards relative to the vertical by 10°. A different angle φ can be set in the following way. After having loosened the fixing element 69 of the angle- adjusting device 59, that technically means loosening of the locking nut 70, the

adjusting element 64 can be turned on the axis 60 relative to the hinge element 63. As the latch 72 is held by the spring 74 in the latch seat 71, the hinge element 65, too, will rotate together with the adjusting element 64, and the hinge element 65 will rotate the upper support means 49 secured to it. Once the plane F of the upper support means 49 is set at the desired angle φ, the hinge element 63 and the adjusting element 64 can be secured to one another again by the fixing element 69.

[159] Although the angle φ can in principle be set in advance if the installation angle of the cover panel 82 is known, the following method is simpler and more accurate. After loosening the fixing element 69 the upper support means must be lifted together with the vertical lifting means 25 to the extent that the cover panel 82 be accommodated into its position, in which position it shall be fastened again by the fixing element 69. This 'analogous' adjusting makes it certain that the cover panel 82 will be positioned in the prescribed angle at its place of installation.

[160] Figures 13 and 14, illustrating an extremely special problem each, show in what way the place where apparatus 1 works can influence the adjusting of the various elements.

[161] Figure 13 shows that the use of apparatus 1 is hindered by a light of stairs. (Of course, any other obstacle may occur in the field, such as a bathtub, an in-built piece of furniture etc.). With the usual adjusting, it would be impossible to install the cover panel 82 above the flight of stairs, into the coverage by its side. This can be solved by using the apparatus 1 presented above in the following way. In foot means 2, the mast holder end piece 20 is pushed along the longitudinal beam element 4 up to the fixing unit 17 at its end, and in the upper support means 49, the longitudinal beam element 51 is also pushed in the same direction in the fixing unit 67 of the angle-adjusting device 59, up to the fixing unit 17 located at its very end. Hence the longitudinal beam 3, the telescoping mast 26 and the longitudinal beam 50 take up a distorted Z-shape (in Figure 13, this appears as an inverse Z-shape, but geometrically this is insignificant). Hence the upper support means 49 extends over the flight of stairs, and the cover panel 82 can be installed above that.

[162] The usual adjusting of apparatus is prevented in Figure 14, too, by a flight of stairs.

Here the lower coverage of the roof structure above the flight of stairs is to be made. Therefore, in foot means 2 the fixing units 17 at the respective ends of the longitudinal beam elements 4 and 5 are pushed along the cross-bearing elements 14 up to the rollers 18 at their end, while on the upper support means 49 the cross-members 53 are pushed up to their end, in the same direction, in the fixing units 17 at the respective ends of longitudinal beam 50. In this adjusting, the cross-members 13, the telescoping mast 26 and the cross-members 53 make up the distorted Z-shape (here the Z-shape is a little distorted given the inclination of the upper support means 49, but this is of no

relevance for the theoretical shape). As a result, now the upper support means 49 extends over the flight of stairs.

[163] It may happen in the extreme adjusting described above that the common mass point of the apparatus 1 and the cover panel 82 should fall outside the line of rollers 18, that is, the apparatus 1 would tip over. Obviously, this can be prevented quite easily by putting counter-weights on the foot means 2. This is so easy a task for those skilled in the art that there is no need to offer a separate solution for it.

[164] On the basis of Figures 13 and 14, respectively, it is easy to establish the adjusting intervals of the apparatus 1.

[165] In foot means 2, the longitudinal beam element 5 can be pushed fully (up to the fixing unit 17 at its end) into the longitudinal beam element 4, so that the smallest length of the longitudinal beam 3 will be identical with the length of the longitudinal beam element 4. As the lengths of the longitudinal beam elements 4 and 5 are identical, the biggest length of the longitudinal beam 3 is the sum of the lengths of the longitudinal beam elements 4 and 5 (a small overlap due to the fastening in fixing unit

12 notwithstanding). In a similar way, the smallest length of the cross-member 13 is identical with the length of the cross-bearing element 14 and its biggest length with the combined length of the cross-members 14 and 15. Mast holder end piece 20 can be moved along the entire length of the longitudinal beam element 4, and the fixing unit 17 along the entire length of the cross-bearing element 14.

[166] In the upper support means 49, the longitudinal beam element 52 can be pushed completely into the longitudinal beam element 51, and hence analogously with the above, the smallest length of the longitudinal beam 50 is identical with the length of the cross-bearing element 51 and its biggest length with the combined length of the cross-members 51 and 52. Fixing unit 67 of the angle-adjusting device 59 can be set anywhere along the entire length of the longitudinal beam 51, and the fixing units 17 at the respective ends of the longitudinal beam 50, they can be pushed along the entire length of the cross-members 53. In the same way, the clips 54, too, can be set at any place along the entire lengths of the cross-members 53.

[167] Hence as a result of the adjusting options, the floor area to be occupied by apparatus 1 can be reduced to one quarter, and hence the apparatus 1 can be used in very confined premises, too (such as toilets).

[168] It is easy to understand on the basis of Figures 13 and 14 that the usefulness of apparatus 1 is not influenced in the least by that vertical lifting means 25 is only movable along one half of both longitudinal beam 3 and longitudinal beam 50, and in the same way, longitudinal beam 3, too, can only be moved on one side of the cross- members 13. (That is, for example the mirror image of the adjusting depicted in Figure

13 is apparently impossible to create.) The problem, however, can be solved easily by

pulling out the longitudinal beam elements 4 and 5 of the longitudinal beam 3 from mast holder end piece 20, and putting them back from the opposite side, and the same procedure is applied for the longitudinal beam elements 51 and 52 of the longitudinal beam 50. Of course, if the problem occurs exclusively for the cross-members 13, said procedure can be applied for these, too.

[169] The adjusting of apparatus 1 depicted in Figures 13 and 14, respectively, on the other hand, can be used in combination, too, which will allow a two-dimensional shift of the upper support means 49.

[170] Once apparatus 1 is set according to the criteria mentioned above, the cover panel

82 can be raised by it. For the purpose of illustrating the individual steps, let us speak of such a cover panel 82 as shall be installed in the manner depicted in Figure 14.

[171] Before describing the individual steps, let us highlight one more criterion of the realization of this construction. Cover panels 82 are of a rather big size as well as weight. Therefore, it is easier to lift them to apparatus 1 if they are stood on their edge. For that purpose, plane F of the upper support means 49 must also be positioned vertically. This is solved by the angle-adjusting device 59 according to the invention.

[172] Figures 15 A to C show an angle-adjusting device 59 which is identical in terms of theoretical design with the one in Figures 11 and 12, except that here for the sake of providing a clearer overview, the diameters of the hinge element 63, the adjusting element 64 and the hinge element 65 are different, and the pair of latch seat 71 and latch 72, too, is arranged radially.

[173] In Figure 15 A, the angle-adjusting device 59 is shown in normal position, that is, the angle φ enclosed by plane F of the upper support means 49 and the vertical is 10°. In this position, the cushion surface 78 on the bracket 66 sits on the cushion surface 77 of the buffer 76, and the fixing element 69 secured to the adjusting element 65 is in a position Cl and the pair of latch seat 71 and latch 72 in a position Rl.

[174] In order to set an angle φt required for the roof structure 83, the fixing element 69 of the angle-adjusting device 59 is loosened in the manner described above and then the upper support means 49 is raised and, thereafter, the adjusting element 64 is rotated by the angle φt relative to the hinge element 63. By that, the fixing element 69 is turned into a position C2 where it is secured anew. As in the meantime the latch seat 71 - latch 72 pair has already been latched, the hinge element 65 rotates together with the adjusting element 64, by the angle φt, and hence the latch seat 71 - latch 72 pah- takes up a position R2. Consequently, plane F of the upper support means 49 now includes an angle φt with the vertical. As can be seen, the cushion surface 78 on the bracket 66 has also rotated away from the cushion surface 77 on the buffer 76.

[175] After that, the upper support means 49 can be lowered.

[176] In order to install the cover panel 82, the upper support means 49 must be put up

again in a quasi- vertical position. To do so, the latch 72 is lifted out of latch seat 73 in the manner shown in Figure 15C. With that, the connection between the adjusting element 64 and the hinge element 65 ceases and the adjusting element 64 can be pivoted back freely so that the latch 72 should again take up position Rl. Then cushion surface 78 butts again on cushion surface 77. At the same time, adjusting element 64 and hinge element 63 remain motionless, that is, the fixing element 69, too, remains in position C2. With that, the plane F of the upper support means 49 once again takes up its original position at the angle φ, and the cover panel 82 stood onto its edge can be placed onto it. (Obviously, the cover panel 82 is held up from below by the clips 54.)

[177] Finally, the upper support means 49 can be tilted back again, together with the cover panel put onto it, until the latch 72 turns back into position R2 and automatically snaps into the latch seat 71. Upon that, the rigid connection between the adjusting element 64 and the hinge element 65 is re-established and the upper support means 49 returns again to its pre-set stable position. Now the cover panel 82 can be raised to its position by the vertical lifting means 25.

[178] Actual utilization following the above actually requires no fuller explanation.

Apparatus 1 must be put at such place where nothing hinders the placing of the cover panel 82 onto the upper support means 49. For the loading operation, the upper support means 49 is lowered, the latch seat 71 - latch 72 pair is loosened, and the plane F of the upper support means 49 is put in a quasi- vertical position. As a matter of fact, as indicated already, the plane F is tilted backwards by an angle of 10° to the vertical, and hence the cover panel 82 cannot fall off it.

[179] After the installation of the cover panel 82, the upper support means 49 can be tilted back by the handle 81 to the angle φt already set, upon which the angle-adjusting device 59 will automatically get blocked.

[180] Finally, by turning the actuating lever 36, the upper support means 49 shall be lifted to the height of the obstacle, e.g. stairs, to be avoided by vertical lifting means 25, and then, by moving the apparatus 1, it can be put in position above the obstacle, and the cover panel 82 can be lifted into its place by the vertical lifting means 25.

[181] After the fixing of the cover panel 82, the above steps shall be reiterated in reverse order to make the apparatus 1 ready for the installation of the next cover panel 82.

[182] Let us emphasize once again in connection with the above detailed description that it only refers to one embodiment of the apparatus according to the invention carried out in practice. Of course, on the basis of the invention, numerous other variants can be worked out. Some of the options introduced below will demonstrate that, too, among others.

[183] First of all, let us note that although for elements which can be adjusted in longitudinal direction relative to one another, continuous adjustment is the most ad-

vantageous solution, the principle according to the invention will be asserted also in case of they can be adjusted by grades, for example with the help of known orienting bores and latching pins. In this case, the last orientation bore at the end of the given element shall be placed so that the other element should 'butt' on the end of the given element. Similarly, the orientation bore series and the latching pin can be used for fixing the clip 54 as well.

[184] Speaking of clips, note that the L-shaped form can be cut out from a plate and fixed on the side of the bracket with the help of a loose rivet as hinge point. In this case, bracing points shall be created on the L-shaped form and the bracket, respectively, in between which a spring returning the holding clip into its normal position can be placed. Whether the holding clip is made of wire or plate, if that is solid enough, it suffices to use a single L-shaped form on one side of the bracket.

[185] As for the fixing itself, obviously, the manner of fixing according to the invention is advantageous also if the respective cross-sections of the parts to be slid into one another fit perfectly, although in this case there is no risk of flap-over. Of course, in this case, the clamping screw can be applied as well.

[186] Instead of screws, other devices, often more useful in the given case, can be used as well. These may include handle-operated eccentric clamping devices, the eccenter of which penetrates through the window made in the wall of the external element into its inner space, or e.g. a wedge being moved perpendicularly with the axis of the elements concerned, etc.

[187] In the manufacturing phase of the actual embodiment of the apparatus, in order to make that as cheap as possible, it seemed reasonable to use hollow profiles of rectangular cross-section. Of course, the method of fixing according to the invention can be used for materials with other cross-sections, too, provided that these are delimited by plane surfaces. In other words, a material having a polygonal cross- section of any kind can be used, but the fixing element has to be arranged adequately. This requires, on the one hand, that the two neighbore external surfaces of the inner element should lean on the two neighbore inner surfaces of the external element, because the already mentioned effect of the two prisms lain in one another will only be created this way. On the other hand, the fixing element shall be installed so that its clamping force should really bear on the two pairs of superimposed surfaces, that is, that the line of action of its clamping force should not be perpendicular with any of the superimposed surface pairs. Of course, it is most advantageous for the line of action of the fixing element to fall on the bisecting plane of the two superimposed surface-pairs. This can be achieved by making the aperture for the fixing element diagonally opposite the common edge of the two superimposed surface-pairs in the wall of the external element, and upon the fixing of the inner element, the fixing element relies on the

surface opposite to the common edge of the two leaning abutting surfaces of the inner element.

[188] Such clamp-like devices can also be used for connecting the longitudinal beam and the cross-member as are built at the end of the longitudinal beam, and pulled together by a screw arranged outside the cross-member segment. Similar clamp-type devices can be used for mounting the vertical lifting means, too.

[189] Instead of using hollow profiles, both these clamp-type devices and the brackets used for the various fixing units described above can be made in other ways, too, for example by bending and welding of flat steel or by casting.

[190] As for the angle-adjusting device, several variants should be mentioned.

[191] Two differences have already been shown in Figures 15 A to C, namely that, firstly, the two hinge elements and the adjusting element may be of different diameters and, secondly, that the latch seat can also be arranged in the edge of the given element.

[192] From the point of view of the principle of the invention, the most important difference relates to latching of the adjusting element and the hinge element belonging to the upper support means. The adjusting element can also be designed with several orientation bore in the front surface on the side of the hinge element, arranged on a concentric arc, at identical pitches, but without a buffer on the hinge element of the vertical lifting means. The operation of the angle-adjusting device created this way hardly differs from that of the one presented above. In order to tilt the upper support means back to vertical position after having set the angle φt between the hinge element belonging to the vertical lifting means and the adjusting element, the latching between the adjusting element and the hinge element belonging to the upper support means shall be undone by removing the locating pin; the upper support means shall be tilted back to its quasi- vertical position, and the locating pin shall be inserted in the closest orientation bore. If the orientation bores are distributed densely enough (at every 10°, for example), the angle of the upper support means to the vertical will be changed within a small range.

[193] The value of the angle φ is chosen arbitrarily or, more precisely, on basis of previous experiences. This is the value at which the cover panel placed on the upper support means will certainly not tip over any more, and which makes it easy to keep it in hand. One may say that angle φ should preferably be chosen in the range of 0° to 15°

[194] Mention should be made by all means of the fact that although the simplest apparatus can be made by arranging the adjusting element in between the two hinge elements, there is no problem if a construction problem of some kind can only be solved by a different arrangement order. If the hinge element belonging to the vertical lifting means and the hinge element belonging to the upper support means are arranged

side by side, the adjusting element might be, for example, a ring sector fitting to the superficies thereof, and in this case the arcuate path of movement of the pin secured to the hinge element can be created in the adjusting element. (Of course, the path is arcuate in this case not in its plane, but perpendicularly to it.)

[195] Finally, as can be seen from the previous example, too, from the point of view of the operation of the angle-adjusting device it is irrelevant whether the arcuate path - fixing element pair or the latch seat - latch pair is created on the hinge element belonging to the vertical lifting means or on that of the upper support means as well as to which of these elements is created on the adjusting element and the hinge element, respectively.

[196] On the basis of the embodiment of the apparatus according to the invention carried out in practice and the variants mentioned by way of example, it will be easily understood without any further explanation that the invention provides such apparatus for the lifting and installation of cover panels as is advantageous in several respects.

List of used reference signs

[197] Cl position

[198] C2 position

[199] F plane

[200] Rl position

[201] R2 position

[202] Sl plane

[203] S2 plane

[204] Tl axis

[205] T2 axis

[206] φ angle

[207] φt angle

[208] 1 apparatus

[209] 2 foot means

[210] 3 longitudinal beam

[211] 4 longitudinal beam element

[212] 4a surface

[213] 4a' surface

[214] 4b surface

[215] 4b' surface

[216] 5 longitudinal beam element

[217] 5a surface

[218] 5b surface

[219] 6 bracket

[220] 7 aperture

[221] 8 aperture

[222] 9 projection

[223] 10 through-bore

[224] 11 fixing element

[225] 12 fixing unit

[226] 13 cross-member

[227] 14 cross-member element

[228] 14a surface

[229] 14b surface

[230] 15 cross-member element

[231] 16 bracket

[232] 17 fixing unit

[233] 18 roller

[234] 19 locking brake

[235] 20 mast holder end piece

[236] 21 bracket

[237] 22 bracket

[238] 23 fixing means

[239] 24 fixing means

[240] 25 vertical lifting means

[241] 26 telescopic mast

[242] 26a mast element

[243] 26b mast element

[244] 26c mast element

[245] 27 sliding insert

[246] 28 cable

[247] 29 pulley

[248] 30 pulley

[249] 31 pulley

[250] 32 pulley

[251] 33 slot

[252] 34 winch

[253] 35 cable drum

[254] 36 lever

[255] 37 locking screw

[256] 38 axle

[257] 39 safety device

[258] 40 bracket

[259] 41 elongated bore

[260] 42 brake wedge

[261] 43 brake surface

[262] 44 axle

[263] 45 window

[264] 46 link

[265] 47 pin

[266] 48 tension spring

[267] 49 upper support means

[268] 50 longitudinal beam

[269] 51 longitudinal beam element

[270] 52 longitudinal beam element

[271] 53 cross-member

[272] 53a surface

[273] 53b surface

[274] 54 clip

[275] 55 bracket

[276] 55a surface

[277] 55b surface

[278] 56 fixing means

[279] 57 appendage

[280] 58 buffer

[281] 59 angle-adjusting device

[282] 60 axis

[283] 61 nut

[284] 62 socket piece

[285] 63 hinge element

[286] 64 adjusting element

[287] 65 hinge element

[288] 66 bracket

[289] 67 fixing unit

[290] 68 arcuate path

[291] 69 fixing element

[292] 70 locking nut

[293] 71 latch seat

[294] 72 latch

[295] 73 spring housing

[296] 74 spring

[297] 75 handle

[298] 76 buffer

[299] 77 cushion surface

[300] 78 cushion surface

[301] 79 bracket

[302] 80 fixing unit

[303] 81 leg

[304] 82 cover panel

[305] 83 roof structure