Levelling machine

Abstract: Levelling machine, more particularly for levelling a floor layer (2), of the type whereby the levelling is performed by means of a rotating base structure (3), characterized in that this base structure (3) comprises a support structure formed by a disc (7).

Description: This invention relates to a levelling machine, particularly for levelling and/or for polishing a floor layer. In general, this levelling machine can be applied for the treatment of any floor layer which is made from a flattened quantity of material, for example concrete, floor plaster, and so on. In a particular application, this levelling machine can also be applied for levelling and/or polishing of top layers based on plastic material, for example epoxy mortier, which, as is known, can be applied upon a sublayer of concrete or the like. As known, different additives may be added to such top layers, either by mixing in or by sprinkling over, such as magnesium, quartz, little glass pearls and so on, whereby decorative effects are achieved which show to full advantage particularly after being treated with a levelling machine. It is known that the material concerned is flattened over the floor in a liquid or paste-like condition. Subsequently one waits until the layer has become relatively hard, after which the treatment with the levelling machine is performed. Depending on the type of the material, such levelling machine can also be applied in order to flatten newly applied raw material, for example a mixture of sand and concrete, which at that time is still lying completely unflat. It is known that for this purpose there are existing levelling machines provided with a rotating base structure which is formed by three or four or more flattening blades which are attached on a spider-shaped part. Depending on the material to be processed, a polishing disc may be applied in place of using separate flattening blades, which disc will then be installed loosely under the spider-shaped part and the flattening blades and, during the rotation of the spider-shaped part, will be carried along by means of carrier elements, attached at the top side of the polishing disc, behind which elements the flattening elements are engaging. Such a levelling machine is, among others, described in the Belgian Patent Application No. 09500056 of the present applicant. Although such a levelling machine, which is provided with a base structure with a spider-shaped part, works very efficiently, it shows a number of less advantageous characteristics. For example, at the circumference of the base structure, a protection ring is necessary which has to prevent that the user of the machine might be touched by the flattening blades which are mounted at the ends of the spider-shaped part, and which simultaneously has to prevent that the flattening parts beat against the wall or other objects in the case that it is necessary to work alongside a wall or another object. Such a protection ring complicates the construction considerably and makes it more expensive and furthermore offers very little protection because the danger remains that the user comes into contact with the rotating spider-shaped part via the upper side, through the protection ring. Other protection means than a ring also complicate the construction, anyhow. A spider-shaped part also has the disadvantage that it is composed of different constructive parts, which, as far as the price is concerned, has a relatively large influence upon the total price of the levelling machine. Other known levelling machines have a rotating base construction consisting in the combination of a disc forming a support structure and attached thereto a levelling and/or polishing disc. Such levelling machine is disclosed in DE-U-9010799. Said levelling machine comprises a support disc fixed to a rotating shaft. To this support disc is removably fixed a half-rigid flexible levelling disc presenting at its circumference an edge surrounding the support disc. This flexible disc consists of plastic or of coated aluminium foil. The invention aims at providing a remedy for one or more of the aforementioned disadvantages. It also aims at a levelling machine which is more advantageous than the known machines and more simplier than the machines with a spider-shaped part. To this aim, according to the invention, the levelling machine for levelling a floor layer, and comprising a rotating base structure consisting in the combination of, on the one hand, a support structure formed by a disc extending over the complete or almost the complete working surface of the machine, and, on the other hand a flattening and/or polishing disc mounted thereunder and having an upstanding edge surrounding the support structure forming disc, is characterized in that the flattening and/or polishing disc consists of a thin metal plate presenting a support plane having a flat central part and between this part and the upstanding edge two inclined transition parts which form different angles with the part. Particular embodiments of the invention are set forth in claims 2 to 10. In order to show better the characteristics of the invention, in the following, as example without any limitative character, a preferred form of embodiment is described with reference to the enclosed drawings, wherei.n: figure 1 in perspective shows a levelling machine according to the invention; figure 2 on a larger scale shows a cross section according to line II-II in figure 1; figure 3 shows, in top view, the disc which is indicated by F3 in figure 2; figure 4 shows a cross section according to line IV-IV in figure 3; figures 5 and 6, on a larger scale, show the parts which are indicated by F5 and F6 in figure 2. As shown in figure 1, the invention relates to a levelling machine 1, more particularly for levelling a floor layer 2, of the type whereby the levelling is performed by means of a rotating base structure 3. Besides this base structure 3, the levelling machine 1 mainly consists of a motor 4, a reductor 5 and a control element 6 or such to move the machine over the floor layer 2 to be treated. The motor 4 can, as shown, be a thermic motor, for example a benzine motor, but can also be an electric motor which optionally is equipped with a frequency converter. The levelling machine 1 rests with the base structure 3 upon the floor layer 3, whereby during working this base structure 3 rotates over the floor layer 2 in a horizontal plane. The particularity of the invention consists in that the base structure 3 forms a support structure which is formed by a disc 7, which preferably has the shape of a circle and extends over the complete or almost complete working surface of the levelling machine 1. As mentioned in the introduction, the disc 7 functions as support structure for a flattening and/or polishing disc 8 installed hereunder. The disc 7 which is shown in detail in the figures 3 and 4, consists of plastic, with such a thickness, for example in the order of 20 mm, that it can perform the support function for which it is thought according to the invention. The flattening arid/or polishing disc 8 consists of metal, more particularly steel sheet with a minor thickness in order to limit weight. The base structure 3 is preferably fixed via the disc 7 at a therefore provided machine flange 9, by means of a quick change attachment. As visible in the figures 1, 2 and 5, to this end screw connections 10, formed by bolts 11, extending through the disc 7 and the machine flange 9, and wing nuts 12 are applied, such that these wing nuts 12 are easy attainable along the top side of the base structure 3. It is clear that other quick change attachments can be applied, too, such as for example bayonet connections. The bolts 11 are preferably fixed at the disc 7 such that they remain at their place also during the removal of the base structure 3. To this end, as shown in detail in figure 5, locknuts 13 can be applied which are screwed upon the bolts 11 from the top side 14 of the disc 7 and which can, for example, take place in recesses 15 which are provided in the bottom side of the machine flange 9. The bolts 11 are countersunk with their heads 16 into the bottom side 17 of the disc 7, due to which fact they do not form an obstacle for the installation of the flattening and/or polishing disc 8. The bolts 11 are countersunk such that they become located at a distance D from the bottom side 17 in order to prevent that these bolts 11 leave traces in the floor layer 2, even after the disc 7 might have become somewhat thinner due to abrasion. The base structure 3 is provided with fixation means which allow a preferably positive fixation between the disc 7 and the flattening and/or polishing disc 8. Hereby it is aimed at a fixed connection between the disc 8 and the disc 7 which offers the advantage that the anchorage during transport is guaranteed. These fixation means consists in the shown example in screw connections 18 which are arranged along the circumference of the base structure 3. As shown in detail in figure 6, to this end screws 19 which are countersunk into the disc 7 can be applied which pass through the disc 7 from the top side and can be screwed into screw fittings 20 which are provided at the flattening and/or polishing disc 8. These screw fittings 20 consist in the shown example of nuts 21 which are provided at the top side of the flattening and/or polishing disc 8, which nuts 21 are welded onto the top side 23 by means of intermediate parts 22. By application of countersunk screws 19 the appearance of protruding and dangerous parts at the top side 14 of the rotating disc 7 is excluded. As shown in the figures 3 and 4, the disc 7 itself preferably consists only of a plate of mainly constant thickness, with a number of openings 24 and 25 provided herein, respectively for the bolts 11 and the screws 19. Due to this the disc 7 is particularly simple to realize by means of simple cutting techniques or by means of an injection moulding process. At its edge 26, the disc 7 is preferably provided with at least one rounding 27, which is important in the case that the disc 7 is applied as flattening and/or polishing element. By means of this rounding 27 is achieved that the levelling machine 1 becomes easier to steer, especially if a curve has to be made. Moreover, the generation of so-called grinding marks, which are circle-shaped traces produced by the base structure, is hereby excluded. As indicated by the radius Rl in the enlargement of figure 6, the rounding 27 preferably is a circle-shaped rounding. In order to enlarge the steering ease even more, the rounding 27 may optionally be preceded by another rounding with a larger radius. The discs 7 and 8, are executed in such a way that they fit precisely into each other in order to obtain that the disc 7 exercises a centering effect onto the flattening and/or polishing disc 8. In order to obtain that the discs 7 and 8 fit precisely into each other, the flattening and/or polishing disc 8 is provided with a standing, preferably vertical edge 28 fitting precisely around the disc 7. The fact that the standing edge 28 is vertical enables working very narrowly alongside a wall. The flattening and/or polishing disc 8 is also provided with a rounding 29 which is preferably realized with a radius R2 of a circle, in order to avoid the so-called cutting. According to a particular feature of the invention, the flattening and/or polishing disc 8 comprises a support plane 30 having, next to the outward circumference, as shown in figure 2, two transition parts 31 and 32 showing straight lines in cross section, which parts form different angles A and B with the horizontal plane. The central part 33 in between these is flat and extends perpendicular onto the rotation shaft 34. The transition part 31 serves for the prevention of the so-called cutting of the disc into the floor layer 2 and also offers the property that the material of the floor layer or, optionally, material to be polished into the floor layer 2, is easily drawn under the disc 8 and processed. The transition part 32 which extends under a smaller angle than the transition part 31 allows for the levelling machine 1 to turn into one or other direction simply by tipping, by exerting a suitable pressure onto the handle 6, without running the risk that the levelling machine eventually may gyrate away. The angles A and B are, for example, of the order of 5 and 3 degrees, respectively. The radial length L1 of the transition part 31 is preferably considerably smaller than the radial length L2 of the transition part 32. The length L2 is preferably 1,5 up to 2,5 as large as L1. The radial length L3 of the central part is preferably equal to 0,5 up to 0,7 times the total length L4 of the radius of the base structure 3. The transitions between the inclinations are gradual. The transition parts 31 and 32 may also consist of curved planes. Attention is drawn to the fact that, according to the invention, the aforementioned disc 7 might also be provided with similar transition parts. The operation of the levelling machine 1 can easily be deducted from the figures and the aforegoing description. By starting the motor 4 and switching on the rotative movement of the base structure, the flattening and/or polishing disc 8 effects a levelling and/or polishing function on the floor layer 2. It is clear that the device, which is described by means of the figures, provides all advantages compiled in the introduction. The present invention is in no way limited to the form of embodiment described as example and represented in the figures, on the contrary can such levelling machine and base structure be realized in various forms and dimensions without leaving the scope of the invention. It is also not excluded to fix the discs 7 and 8 to each other by means of a permanent connection. The aforementioned disc 7 can also consist of another material than plastic, such as wood or an aluminium alloy, whereby in that case a number of advantages will expire, which, of course, must not be a disadvantage if one wants to achieve a particular application.

Claims: Levelling machine for levelling a floor layer, comprising a rotating base structure (3) consisting in the combination of, on the one hand, a support structure formed by a disc (7) extending over the complete or almost the complete working surface of the machine, and, on the other hand a flattening and/or polishing disc (8) mounted thereunder and having an upstanding edge (28) surrounding the support structure forming disc (7), characterized in that the flattening and/or polishing disc (8) consists of a thin metal plate presenting a support plane (30) having a flat central part (33) and between this part (33) and the upstanding edge (28) two inclined transition parts (31-32) which form different angles (A and B) with the part (33). Levelling machine according to claim 1, characterized in that the inermost of the two inclined transition parts (31-32) extends over a longer radial distance (L2) than the outermost transition part (31). Levelling machine according to claim 1 or 2, characterized in that the inclined transition parts (31-32) form angles with the plane of the flat central part (33) of about 3 and 5 degrees respectively. Levelling machine according to any one of claims 1 to 3, characterized in that the flattening and/or polishing disc (8) presents a rounding (29) between its upstanding edge (29) and its support plane (30). Levelling machine according to any one of claims 1 to 4, characterized in that the disc (7) forming the support structure consists of plastic. Levelling machine according to any one of claims 1 to 5, characterized in that the disc (7) forming the support structure is provided with a quick change attachment with which it can be attached to a machine flange (9). Levelling machine according to claim 6, characterized in that the quick change attachment comprises bolt connections with bolts (11) which are passed through the disc (7) via the bottom side (17), whereby the bolts (11) are countersunk in the disc (7) in such a way that they become located at a distance (D) from the bottom side (17) of the disc (7). Levelling machine according to claim 6 or 7, characterized in that the quick change attachment comprises bolts (11) which are passed through the disc (7) via the bottom side (17) and wing nuts (12) screwed on the bolts (11). Levelling machine according to any one of claims 1 to 8, characterized in that the base structure (3) is provided with attachment means providing a positive attachment between the disc (7) forming the support structure and the flattening and/or polishing disc (8), which means consist of screw connections (18) being arranged along the circumference of the base structure (3). Levelling machine according to claim 7 or 8 and to claim 9, characterized in that the disc (7) forming the support structure consists of a plate of constant thickness with a number of openings (24 and 25) provided therein for the bolts (11) and screws (19) of the screw connections (18).

Inventors: RIJKERS W C H M, RIJKERS, W.C.H.M.
Applicants: B MAC BESLOTEN VENNOOTSCHAP ME, B-MAC, BESLOTEN VENNOOTSCHAP MET BEPERKTE AANSPRAKELIJKHEID
Application year: 1996
Main classification: E04F21
IPC codes: E04F21