Milling drum for scarifier machines

Abstract: The invention realises a milling drum (1; 100; 200) for scarifier machines which comprises a plurality of annular elements (4, 5) coaxially arranged outside a core (2) connected with the driving shaft of the scarifier machine, supplied with operating protruding elements (6) arranged like a spiral and suitable for shuttering the soil to remove. Said annular elements comprise at least two ending annular elements (3) realised one - piece and one or more intermediate annular elements (4, 5) in between said ending annular elements (3), where at least one (4) of said one or more intermediate annular elements is formed of at least two shells (41) supplied at the ends with radial flanges (411) opposable among them which are united by fastening means (412) in order to render these annular elements (4, 5, 3) integral among them and with said core (2).

Description: The invention concerns a milling drum suitable for being used in scarifier machines which are used for the removal of road surfaces. As it is known, scarifier machines supplied with a milling drum, equipped with a plurality of operating protruding elements, are used in order to realise excavations or for the removal of the asphalt surface which covers the carriageways. The operating elements are brought in contact with the soil to be removed, and during the rotation of the drum they shatter it, permitting its removal in this way. The scarifier machines are produced in different embodiments which are primarily different with respect to the width of the milling drum, which determines the kind of work to which the machine can be allocated. During the execution of road works, it is frequently required to remove the soil for stretches of a rather limited width, for example when it is necessary to dig some ditches, for the interment of electric and telephonic cables, of pipes, or others, and in this case it is necessary to use scarifier machines equipped with a milling drum of a limited width. Since the companies which execute the work do not always have machines with small-sized milling drums, tractors, mechanical shovels, or similar machines are often used for narrow milling or digging operations, with such machines being equipped with some special milling aggregates which permit to realise narrow excavations. Such solutions do not permit high efficiency and are often uneconomical. In an attempt to overcome such inconvenience, so called "universal" scarifier machines are usually used, in which the milling drum is formed of a fixed part, firmly connected with the driving shaft. On this fixed part, a removable part is arranged, said removable part being formed of a plurality of rings with each ring being formed of a pair of semicircular shells, on which the operating protruding elements, are arranged. The semicircular shells are connected to each other by flanges. Thus, a user can perform excavations of a different width, which depends on the number of rings that are arranged on the fixed part. However the milling drums of the described kind present some inconveniences. A first inconvenience is that the flanges, which connect the semicircular shells that form each ring, create an interruption of the flow of the material which, during the removal, is conveyed along the spirals formed by the operating elements. Therefore, the flanges create an obstruction that compromises the good performance of the production. Another inconvenience is that the presence of such fastening flanges prevents the helical flow of the shattered material along the drum in between the operating elements. EP-A-0 735 192 describes a scarifier machine, equipped with a milling drum formed of rings that are axially threaded into the shaft of the milling drum. The number of rings is selected to obtain the desired width of the milling drum. Applying such a solution, the user of the scarifier machine can realise a variable digging width, according to the number of the rings which are used, but such solution presents the inconvenience that it cannot always be applied to every kind of machine, since the possibility of reaching laterally the milling drum, in order to install and remove the rings, is given in all scarifier machines. Besides, in case of large-sized drums and given the construction of the scarifier machine, it is always difficult to reach milling drum laterally in order to change the composition of the rings. Further, attention is drawn to EP-A-0 694 651 which describes a modification of a cold milling machine used to remove concrete and asphalt from an existing highway. The milling machine includes a milling drum segmented into two or more sections with the drive train for the milling drum passing through the core of the milling drum and supported via a journal or bearing to the outside of the machine. One or more sections of a milling drum may be added to the drum to vary its width. The sections of the milling drum can be added by bolting segments of the drum onto a driven sleeve which telescopes over the drive shaft of the machine. The segments of the milling drum can be readily removed by loosening a few bolts and removing the segments without having to slide off a milling drum segment at either end of a drive shaft. According to the invention a milling drum as set forth in claim 1 is provided. Preferred embodiments are disclosed by the dependent claims. The present invention overcomes the above mentioned inconveniences. In particular, it is an object of the invention to realise a milling drum of variable width which permits to perform excavations of a different width. Another object is that such variation of the width of the milling drum is easily realised, particularly on large-sized drums. A further object is that such variation of the width of the milling drum is easily realised even in those machines in which the side access to the milling drum is difficult or is even prevented. Another object is that the milling drum permits an easy flow of the removed material along a spiral formed by the operating elements of the milling drum. A still further object is that the milling drum, at any used working width, is always equipped with radial shovels suitable for conveying by centrifugal force the removed material on a conveyor belt which moves it away. The mentioned purposes are achieved by a milling drum suitable for being applied to scarifier machines for the removal of soils, as set forth in claim 1. Preferred embodiments of the present invention may be gathered from the dependent claims. According to a preferred embodiment, the milling drum of the invention comprises five intermediate annular elements with one centrally arranged annular element divided in four shells having the shape of a sector of a circle over an arc of 90°, and with the remaining other four annular elements divided in two shells having the shape of a sector of a circle over an arc of 180°. The four shells which form the centrally arranged annular element are connected to each other by radial flanges and fastening means. All the annular elements are arranged one close to the other and are forced reciprocally in correspondence with side conical surfaces realised on their side surfaces and also in correspondence with the end of said core, suitable for favouring the reciprocal axial blocking when the radial flanges of the shells, which form the centrally arranged annular element are fastened. Advantageously, as compared to comparable milling drums of the prior art, the milling drum of the present invention provides an easier assembly and disassembly and a greater versatility in preparing the scarifier machine, according to different embodiments, thus permitting a greater flexibility of employment of the scarifier machine. The mentioned objects and advantages will be better understood from the description of a preferred embodiment of the milling drum of the invention, given as an example but not as a restriction and represented in the enclosed drawings, where: Fig. 1 shows the milling drum of the invention in a front view; Fig. 2 shows the milling drum of Fig. 1 in which the annular element supplied with radial flanges is without a quarter of the shell; Fig. 3 shows the milling drum of Fig. 2 completely without the annular element supplied with radial flanges; Fig. 4 shows in an axionometric view the annular element supplied with flanges, exploded in the four shells which form it; Fig. 5 shows the annular element of Fig. 4 in a side view; Fig. 6 shows the milling drum of Fig. 3 without one of the half-shells which form one of the annular elements without flanges; Fig. 7 shows the milling drum of Fig. 6 without one of the side annular elements without said flanges; Fig. 8 shows the core of the milling drum supplied with two only ending annular elements; Fig. 9 shows, in an exploded axionometric view, one of the annular elements without flanges; Fig. 10 shows in a side view one of the ending annular elements represented in Fig. 8; Fig. 11 shows the milling drum of the invention represented in Fig. 1, in a longitudinal sectional view; Figs. 12 to 19 show the composition phases of the milling drum of the invention according to an embodiment represented in Fig. 19; Fig. 20 shows the milling drum of the invention arranged according to another embodiment. The milling drum of the invention, in the embodiment shown in Figs. 1 and 11, where it is indicated as a whole with 1, comprises a core 2 connected with the driving shaft of a scarifier machine not represented in the figures, on which, outside and coaxially, a plurality of annular elements is arranged comprising: two integrally formed annular end pieces 3, one of which is represented in detail in Fig. 10; five intermediate annular elements in between said annular end pieces 3, with a centrally arranged annular element 4, and two annular elements 5 arranged on each side thereof. Outside said annular elements 3, 4 and 5, a plurality of operating protruding elements is applied, each of them indicated as a whole with 6, which are arranged like a spiral and that are suitable for shattering the soil for removal. The annular elements 3, 4 and 5 are rotated by said core 2 by keying means which are formed of a rib or key 7 extending along the whole length of the core 2 and which mates with seats or recesses in each of said annular elements 4 and 5. As may be seen best in Fig. 11, the annulary elements 4 and 5 are arranged in close contact with each other at inclined or conical surfaces 8. Fig. 9 shows that each of the lateral annular elements 5 is formed of two semicircular shells 51, while the central annular element 4, as may be seen in particular in Figs 4 and 5, is formed of four shells 41, each corresponding to a quarter of a circle, which are connected to each other by radial flanges 411 and bolts 412. As mentioned above and according to Fig. 11, the axial stability of the annular elements 3, 4 and 5 among them and compared with the core 2 when the milling drum is formed, is guaranteed by axial locking or wedging at said inclined surfaces 8, that is realised when the shells 41, which form the central annular element 4, are fastened by said bolts 412 which clamp the flanges 41. In particular each annular end piece 3 axially presses against the conical ring 31, visible in Fig. 12, fixed by screws 311 to the core 2. Besides, as Figs. 2 to 8 show, all the lateral annular elements 5 and also the annular end pieces 3 are axially connected among them by connecting pins 19 which also transmit the coupling forces from the core 2. As may be seen in Figs. 4 and 5, the central annular element 4 is provided, on the side surfaces of the shells 41, with inclined slots 420 having a lateral opening 421, each of them suitable for receiving a pivot or pin 19 when said shells 41 are radially coupled with the core 2 according to the direction 415 shown in Fig. 3. As may be seen from Fig. 6, the connection of the lateral annular elements 5 occurs by axial shifting of each shell 51 in the direction 515. The milling drum of the invention, represented in Fig. 1, presents therefore, after the assemblage, a symmetrical configuration with respect to the transversal axis 10, which can be obtained starting from the configuration represented in Fig. 8 where only two annular end pieces 3 are present on the core 2. By axially coupling the shells 51 of the lateral annular elements 5 with the end pieces 3 or with an adjacent lateral annular element 5 according to the directions 515, inserting each pin 19 in the corresponding hole opposed to it, it is possible to pass through the configurations represented in Figs. 7, 6 and 3, finishing the assembly by radially coupling, in the direction 415, the shells 41 forming the central annular element 4. Fastening or clamping of the bolts 412 unites the flanges 411 and axially forces the shells 41 of the central annular element 4 against the shells 51 of the lateral annular elements 5, in correspondence with the inclined surfaces 8, obtaining the axial clamping of all the annular elements among them and to the core 2. The milling drum can also be realised according to a different configuration, for example as represented in Fig. 19, in which it is indicated with 100, this configuration being suitable for realising an excavation having a width 70 (Fig. 17), smaller than the length of the core 2. In order to realise such configuration, some stopping elements are used, said stopping elements formed of distance rings or spacers, which are indicated as a whole with 9 and represented in particular in Figs. 13 and 14. The distance rings are arranged outside the core 2 in the zones where no annular elements 4 or 5 are used. Said distance rings 9 are formed of two half-rings 91 and axially mate one close to the other by contacting each other at inclined or conical surfaces 92provided on each of said distance rings. As may be seen in Figs. 13 to 16, the distance rings 9 are coupled in order to realise such a configuration on the free zone 20 of the core 2, beginning from the configuration represented in Fig. 12, where both said annular end pieces 3 are moved to one side of the core 2,. As Fig. 16 shows, the assembly of one or more distance rings 9 determines the position of one of the annular end pieces 3, and then, as Fig. 17 shows, the other annular end piece 3, opposite to the previous one, is moved towards the center in the core 2 in order to arrange another couple of distance elements 9, as Figs. 17 and 18 show. Taking reference to Fig. 19, the milling drum is thus formed of an single central annular element 4 and of a couple of annular end pieces or annular elements 3, where said annular elements are symmetrically arranged with respect to the transversal axis of the drum. The distance 70 between the annular end pieces 3 forms, as it has just been said, the working digging width of the milling drum. Also in such a case, the clamping of the flanges 411 of the shells 41, which form the central annular element 4, causes the axial wedging or locking of all the coupled elements on the core 2 propagating to the inclined surface 312 of the conical rings 31 arranged at the ends, assuring the stiffness of the milling drum so formed. In both these embodiments, each one realising a different digging width, the radial flanges 411 of the central annular element 4 act as conveyor blades which, during the rotation of the drum, move the shattered material by centrifugal force on a conveyor belt (not shown in the figures) which carries the material away from the working area. It can also be observed that only this central element 4 is supplied with said conveyor blades and therefore the material shattered and removed by the operating elements 6 can freely move along the spirals according to which the operating elements 6 are arranged, without finding obstacles unlike the milling drums with modular sections according to the prior art. It is possible to obtain even the configuration represented in Fig. 20 where the milling drum is indicated with 200 and where it can be observed that the annular element 4, supplied with the flanges 411 which act as conveyor blades of the removed material, is not centrally arranged, but it is placed close to one of the ending annular elements or end pieces 3. Therefore it can be no longer called "central annular element". Changing opportunely the number of the annular elements, and also their position, being understood that the ending annular elements 3 should always be present because they define the milling or digging width, it is possible to form milling drums with different shapes in order to realise a different digging or milling width. It is important to observe that the replacement and the shifting of the different annular elements is facilitated by their shell configuration, since those shells are relatively not very heavy and in any case of a lesser weight than in the prior art, thus permitting the assembly and disassembly by an operator with less effort, less danger and more rapidly. This particular embodiment permits therefore to change easily the width of the milling drum, even in those machines in which the drum is hardly reachable from a side due to the presence of obstructing elements. Indeed, in the drum of the invention the replacement of the annular elements is easily realised intervening frontally under the core which supports the annular elements supplied with the operating elements. Also, according to the present invention, blades are obtained on a milling drum which are suitable for conveying the centrifugal force of removed material during the working of the soil, without hindering the shifting of the removed material along the spirals defined by the operating elements of the drum. In implementing the present invention, some modifications can be introduced in the milling drum of the invention, such as, for example, realising annular elements divided in a number of parts different from the one described, or realising annular elements, each of them of a different width.

Claims: Milling drum (1; 100; 200) to be applied to scarifier machines for the removal of soils, comprising: a core (2) connected with a driving shaft of said scarifier machine; a plurality of annular elements (3, 4, 5) coaxially arranged on an outside of said core (2) and axially opposing each other one adjacent to the other, said annular elements being provided with operating protruding elements (6) on a peripheral surface thereof, said operating protruding elements (6) being arranged like a spiral and being suitable for shattering the soil to be removed; keying means (7) for transmitting the rotation from said core to said annular elements (3, 4, 5); characterised in that said annular elements comprise: at least two annular end pieces or elements (3), each of the two annular end pieces (3) being a one-piece construction and axially engaging at least one stopping means (9, 31) which is coupled to the outside of said core (2), at least one of said stopping means (31) being fixed to one corresponding end of said core (2); at least one intermediate annular element (4, 5) being disposed between said two annular end pieces (3), at least one (4) of said intermediate annular elements (4, 5) being formed of at least two shells (41) being provided at respective ends thereof with radial flanges (411) opposable to each other, wherein said annular end pieces (3) and said intermediate annular elements (4, 5) are provided with connecting means (19) rendering the end pieces and intermediate annular elements integral with each other and with said core (2) when said radial flanges (411) are connected with each other by fastening means (412). Milling drum (1; 100; 200) according to claim 1, wherein one of said intermediate annular elements (4) is formed of four shells (41), each of them presenting the profile of a sector of a circle over an arc of 90°, said four shells (41) being supplied at each end with one of said radial flanges (411), wherein each of the remaining intermediate annular elements (5) is composed of two shells (51) each of them presenting the profile of a sector of a circle over an arc of 180°. Milling drum (1; 100; 200) according to claim 1 or 2, wherein said connecting means suitable for rendering said annular elements (3, 4, 5) integral with each other and with said core (2) comprise pivots or pins (9) mating with seats (190; 420) provided in an adjacent annular element (3, 4, 5). Milling drum (1; 100; 200) according to one of the preceding claims, wherein said end pieces (3) and intermediate annular elements (4, 5) are provided on side faces thereof with at least one first inclined surface (8) suitable for realising the axial blocking of said end pieces (3) and intermediate annular elements (4, 5) and of said stopping elements (9, 31) with each other and with said core (2) when said radial flanges (411) are connected among them by said fastening means (412). Milling drum (1; 100; 200) according to one of the preceding claims, wherein said stopping means are formed by distance rings (9, 31) coupled to the outside of said core (2), said distance rings (9) being provided with at least one second inclined surface (92; 312) axially engaging each other. Milling drum (1; 100; 200) according to one of the preceding claims, wherein one of said stopping elements is formed of a circular ring (31) fixed at each end of said core (2), wherein further stopping elements (9) are respectively formed of two half-shells (91) of semicircular shape. Milling drum (100) according to one of the preceding claims, wherein said at least one intermediate annular element (4) supplied with said radial flanges (411), and coupled with said core (2) is arranged in a direct axial contact with both said annular end pieces (3). Milling drum (200) according to one of the claims 1 to 6, wherein said at least one intermediate annular element (4) supplied with said radial flanges (411), and coupled with said core (2) is arranged in direct contact with one of said annular end pieces (3) and indirectly with respect to the other annular end piece (3) with the interposition of one or more further annular elements (5). Milling drum according to one of the claims 1 to 6, wherein said at least one intermediate annular element (4) supplied with said radial flanges (411) and coupled with said core (2) is interposed in between a plurality of further annular elements (5) wherein at least two of the further annular elements (5) are in corresponding contact with both side faces of said at least one intermediate annular element (4). Milling drum (1; 100; 200) according to claim 3, wherein said seats suitable for receiving said pins (19) are hollows (190). Milling drum according to claim 3, wherein said seats for receiving said pins (19) are inclined slots (420) having an opening permitting the coupling with the corresponding pin (19) in a radial direction (415) with regard to the pin (19) itself.

Inventors: GELAI LUCIANO, GELAI, LUCIANO
Applicants: BITELLI SPA, BITELLI S.P.A.
Application year: 1998
Main classification: E01C23
IPC codes: E01C23, B28D1