EP3268568B1

EP3268568B1 - Excavating head

Info

Publication number: EP3268568B1
Application number: EP16719129.5A
Authority: EP
Inventors: Silvano PALMIERI
Original assignee: Palmieri SpA
Current assignee: Palmieri SpA
Priority date: 2015-03-12
Filing date: 2016-03-11
Publication date: 2019-05-08
Anticipated expiration: 2036-03-11
Also published as: EP3268568A1; WO2016142909A1

Description

Technical Field

The present invention relates to an excavating head.

Background Art

With reference to the sector of the construction of large works such as tunnels, bridges, dams, aqueducts, foundation pits and the like, it is known to make excavations in a descending direction.
To date, descending excavations are carried out by means of excavating heads or, alternatively, by means of the so-called "coring" technique.
The heads of known type are usually operated in rotation by means of a driving machine, which makes them rotate around a vertical axis gradually as the excavation progresses in depth.
In detail, heads are in use having a plurality of excavation tools arranged staggered and a central opening crossed by a suction pipe able to aspirate the excavated material.
However, the heads of known type have some drawbacks among which must be included the fact that the suction pipe allows to remove small amounts of excavated material.
In particular, as one progresses in depth, the height difference increases between the head and the external environment at the top of the excavation, making aspiration more difficult and expensive from an energy point of view.
Another drawback is represented by the fact that the heads of known type have reduced productivity due to the low removal speed of the excavated material that greatly affects the overall excavation speed, leading to long working times. Alternatively, coring consists in the removal of soil by means of a special tool machine, known to the person skilled in the art as core drill.
The core drill comprises a drilling tool, having a hollow cylindrical body, terminating with a diamond cutter made of high strength material and able to abrade the soil to be excavated.
The core drill is usually driven in rotation by means of a driving machine, which makes it rotate around a vertical axis as the excavation progresses in depth.
During the excavation operations, the excavated material gets stuck inside the cylindrical body as it penetrates into the soil; this means that the excavated material accumulates inside the cylindrical body, forming a core of excavated material that must be removed for the recovery of the excavation operations.
For this purpose, the core drill is extracted from the excavation and the core of excavated material is deposited on the outer surface at the top of the excavation; this allows the core drill itself to be reinserted into the soil and the continuation of the works.
It is easy to understand, therefore, that coring enables the removal of small amounts of excavated soil at a time, leading to long working times and to reduced productivity.
Others excavation heads are known from KR 101 401 981 , KR 2011 0133517 , WO 95/08691 , WO9810170 , US 4 804 295 and US 3 967 463 .

Description of the Invention

The main aim of the present invention is to devise an excavating head which allows removing large amounts of excavated material.
Another object of the present invention is to devise an excavating head which allows increasing the removal speed of the excavated material, considerably reducing working times and increasing the overall productivity of the head itself.
Another object of the present invention is to devise an excavating head which allows to overcome the mentioned drawbacks of the prior art within the ambit of a simple, rational, easy, effective to use and affordable solution.
The above mentioned objects are achieved by the present excavating head having the characteristics of claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become better evident from the description of a preferred, but not exclusive, embodiment of an excavating head, illustrated by way of an indicative, but non-limiting example in the accompanying drawings, wherein:

Figure 1 is an axonometric view from below of the head according to the invention;
Figure 2 is an axonometric view from above of the head according to the invention;
Figure 3 is a front sectional view of the head according to the invention;
Figure 4 is a front sectional view of the head according to the invention in operative configuration.

Embodiments of the Invention

With particular reference to such figures, reference number 1 globally indicates an excavating head.
The head 1, in particular, allows performing dry excavations.
In the context of this treatise by "dry excavations" are meant excavations that take place in the absence of water, or in terrestrial conditions in the absence of water tables.
The head 1 comprises an attachment element 2 to a driving machine to place the head itself in rotation.
With reference to the particular embodiment shown in the illustrations, the attachment element 2 is a flange with bolting holes 3.
The flange 2 can be coupled to a corresponding flanged plate 4 equipping the driving machine.
The placing in rotation takes place around a central axis 5 of the head 1, which also identifies the direction of excavation 6.
Advantageously during excavating operations, the central axis 5 is vertical and the direction of excavation 6 is downwards.
In this regard, it is specified that in the present treatise expressions such as "high", "low", "upper", "lower", "above", "below" and the like, are to be deemed with reference to an operative configuration wherein the head 1 is used for downward vertical excavations.
It cannot however be ruled out that the direction of excavation 6 can be horizontal, in which case the head 1 is used in an operative configuration wherein the central axis 5 is horizontal.
The head 1 comprises a plate-shaped body 7 connected to the attachment element 2 and having a first main face 8 and a second main face 10.
With reference to the particular embodiment shown in the illustrations, the plate-shaped body 7 is a substantially circular plate coaxial to the central axis 5. Advantageously, the first main face 8 is facing to the excavation front 9 and the second main face 10 is opposite to the first main face and is connected to the attachment element 2.
In the context of this treatise by "excavation front" is meant the margin defined by the material to be excavated, along the direction of excavation 6.
In the operative configuration, shown in the illustrations, wherein the central axis 5 is vertical, the plate-shaped body 7 is substantially horizontal and the first main face 8 is lower than the second main face 10.
The head 1 comprises at least an excavation tool 11 associated with the plate-shaped body 7 so as to protrude at least in part, and downwards, from the first main face 8.
Advantageously, the plate-shaped body 7 comprises a plurality of excavation tools 11.
Conveniently, each excavation tool 11 is housed at least in part within a housing seat 12 formed in the plate-shaped body 7.
In particular, each excavation tool 11 emerges (i.e. protrudes) from the first main face 8 for at least one-twentieth of its volume.
The excavation tools 11 have variable shape and size according to the type and dimensions of the excavation.
With reference to the particular embodiment shown in the illustrations, the excavation tools 11 are composed of a substantially cylindrical or frusto-conical body having a sharp or abrasive outer surface.
Conveniently, the excavation tools 11 are mounted idle on the plate-shaped body 7.
In the present case, each excavation tool 11 is associated with the plate-shaped body 7 by means of axial pins 13 separate and parallel to each other which allow its free rotation around a central axis of symmetry of the excavation tool 11.
With reference to the particular embodiment shown in the illustrations, the excavation tools 11 are arranged asymmetrically with respect to the central axis 5 and have axes of rotation with different inclinations according to their position on the plate-shaped body 7.
For example, the excavation tools 11 arranged in the proximity of the central axis 5 have the axis of rotation substantially coplanar to the first main face 8, whereas the excavation tools 11 arranged peripherally to the plate-shaped body 7 have the axis of rotation inclined with respect the first main face 8, i.e. arranged neither vertically nor horizontally.
The head 1 comprises suction means 14, 15, 16 of the excavated material 17 associated with the plate-shaped body 7.
The suction means 14, 15, 16 comprise a storage chamber 14 of the excavated material 17.
With reference to the particular embodiment shown in the illustrations, the plate-shaped body 7 has a lateral perimeter of a substantially circular shape from which extends a side wall 18 of the storage chamber 14 which, advantageously, has a substantially cylindrical shape.
At the end of the excavation operations, the side wall 18 can be lifted upwards with respect to the plate-shaped body 7 to allow the excavated material 17 to exit.
In this regard it should be emphasized an important characteristic of the present invention, that is, the fact that the head 1 must not be reversed to eject the excavated material 17 but, simply by lifting the side wall 18, the excavated material 17 exits from the storage chamber 14.
Furthermore, said storage chamber 14 has an open upper portion 19 and a closed lower portion 20.
Conveniently, the closed lower portion 20 comprises a storage surface 21 of the excavated material 17 adjacent to the second main face 10 and defining the bottom of the storage chamber itself.
In the embodiment shown in the illustrations, the storage surface 21 has a substantially frusto-conical shape and is symmetrical to the central axis 5.
The convexity of the frusto-conical storage surface 21 is facing upwards and, in other words, the storage surface 21 is higher in the proximity of the central axis 5, where the upper base of the truncated cone is defined, and lower in the proximity of the side wall 18, where the lower base of the truncated cone is defined.
It is emphasized, however, that alternative embodiments are possible having a substantially flat storage surface, or otherwise inclined.
The suction means 14, 15, 16 also comprise at least an extraction pipe 15 of the excavated material 17 crossing the plate-shaped body 7 from side to side and terminating in the storage chamber 14.
Advantageously, the suction means 14, 15, 16 comprise a plurality of extraction pipes 15, even if different embodiments cannot be ruled out having a single extraction pipe.
Conveniently, the extraction pipes 15 have a substantially circular section.
As is visible in the illustrations, the extraction pipes 15 are arranged symmetrically with respect to the central axis 5.
It cannot however be ruled out that the aforementioned extraction pipes 15 may also be arranged asymmetrically.
Each extraction pipe 15 has a first portion 22 for the inlet of the excavated material 17 which is arranged on the first main face 8 and a second portion 23 for the discharge of the excavated material 17 which is arranged above the storage surface 21.
In particular, the extraction pipes 15 extend vertically starting from the first main face 8 and have a variable extension depending on the height of the storage chamber 14.
In the proximity of the second portion 23, on the other hand, the extraction pipes 15 have a curved profile 24 that changes the orientation of the pipes themselves.
Furthermore, the second portions 23 have a diffuser element 25 able to spread the excavated material 17 on the storage surface 21.
The diffuser elements 25 are joined to the curved profiles 24, which enables the diffuser elements 25 to direct and distribute the excavated material downwards. Advantageously, each diffuser element 25 is directed in a radial manner with respect to the central axis 5.
In other words, each diffuser element 25 and its curved profile 24 are directed along a radius joining the central axis 5 to the side wall 18.
With reference to the particular embodiment shown in the illustrations, the diffuser elements 25 are facing, with respect to the central axis 5, partly towards the outside and partly towards the inside of the storage chamber 14.
It is easy to understand that the aforementioned orientation, together with the frusto-conical shape of the storage surface 21, allows the excavated material expelled by the diffuser elements 25 to slide downwards, homogeneously filling the storage chamber 14 in the proximity of the lateral perimeter of the plate-shaped body 7.
In addition, the suction means 14, 15, 16 comprise an introduction pipe 16 for the forced introduction of pressurized air in the proximity of the excavation front to generate a pressing force able to push the excavated material 17 through the extraction pipes 15.
In other words, the introduction of air in the proximity of the excavation front creates a differential pressure that causes the excavated material to lift and to be conveyed in the extraction pipes 15, this phenomenon being known to the person skilled in the art as "direct flow".
Advantageously, the introduction pipe 16 has a substantially tubular shape and coaxial to the central axis 5.
In detail, the introduction pipe 16 crosses the storage surface 21 and has a first extremity 26 associated with the attachment element 2 and a second extremity 27 associated with the second main face 10.
Conveniently, the introduction pipe 16 is associated with the side wall 18 of the storage chamber 14 by interposition of union and centering means 28, 29.
The union and centering means 28, 29 comprise a plurality of reinforcing ribs 28 associated with the introduction pipe 16 and a plurality of locking elements 29 associated internally with the storage chamber 14 and able to lock the reinforcing ribs 28.
In the embodiment shown in the illustrations, the head 1 comprises three reinforcing ribs 28 equally spaced from each other; this ensures to keep the introduction pipe 16 in position during the excavation operations.
In the present case, each reinforcing rib 28 has, with respect to the central axis 5, a proximal extremity associated with the introduction pipe 16 and a distal extremity associated by interlocking with the corresponding locking element 29. Furthermore, the head 1 comprises a through central hole 30 crossing the plate-shaped body 7 between the first main face 8 and the second main face 10. Conveniently, the central hole 30 is arranged substantially mating the second extremity 27.
In the particular embodiment shown in the illustrations, the central hole 30 coincides with two housing seats 12 of the excavation tools 11; this means that the pressurized air passes through the housing seats 12, lapping the excavation tools 11.
Alternative embodiments cannot however be ruled out wherein the central hole 30 is clear of the housing seats 12.
The present invention also relates to an excavating method comprising the following steps of:

a) providing the head 1 in the operative configuration;
b) excavating the soil by means of the head 1 to obtain a vertical excavation 31. In the present case, the excavation tools 11 are operated in rotation by means of the pressure of the head 1 against the excavation front. At the same time the excavated material 17, passing through the extraction pipes 15, is collected in the storage chamber 14;
c) extracting the head 1 from the vertical excavation 31;
d) discharging the excavated material 17 from the storage chamber 14 on a surface outside of the vertical excavation 31. This operation is carried out by simply lifting the side wall 18 with respect to the second main face 10, so as to open the storage chamber 14 in the proximity of the lateral perimeter of the plate-shaped body 7 and take advantage of the inclination of the storage surface 21 in order to expel the excavated material by gravity. At this point the steps from b) to d) are repeated until reaching a predetermined depth.

It has in practice been ascertained how the described invention achieves the intended objects.
It is emphasized that the particular solution of providing a storage chamber cooperating with a plurality of extraction pipes permits increasing the amount of material removed in the unit of time and greatly increases the productivity of the excavating head.
In particular, the collection of the excavated material in the storage chamber allows the use of compressed air without reaching excessively high values of pressure that would result in considerable energy consumption. Thanks to the collection chamber, in fact, the excavated material must not be inconveniently pushed to the outer surface of the excavation, but it goes back to the top only by a portion equal to the height of the extraction pipes before arranging in the storage chamber itself.
Moreover, the fact of providing a storage chamber with a frusto-conical storage surface and a side wall movable upwards permits a considerable saving of time in the discharge operations of the excavated material.

Claims

Excavating head (1), comprising:
- at least an attachment element (2) to a driving machine to place said head (1) in rotation around a central axis (5);

- at least a plate-shaped body (7) connected to said attachment element (2) and having at least a first main face (8) and at least a second main face (10) opposite to each other, said first main face (8) being facing to the excavation front (9) and said second main face (10) being facing to said attachment element (2); and

- at least an excavation tool (11) associated with said plate-shaped body (7) so as to protrude at least partly from said first main face (8);

- suction means (14, 15, 16) of the excavated material (17) associated with said plate-shaped body (7) and comprising:
- at least a storage chamber (14) of said excavated material (17);

- at least an extraction pipe (15) of said excavated material (17) crossing from side to side said plate-shaped body (7) and terminating in said storage chamber (14);
characterized by the fact that said suction means (14, 15, 16) comprise at least an introduction pipe (16) for the forced introduction of pressurized air in the proximity of said excavation front (9) and to generate a pressing force able to push said excavated material (17) through said extraction pipe (15).
Head (1) according to claim 1, characterized by the fact that said plate-shaped body (7) has a lateral perimeter of circular shape from which extends said storage chamber (14) with a substantially cylindrical shape.
Head (1) according to one or more of the preceding claims, characterized by the fact that said storage chamber (14) comprises a storage surface (21) of said excavated material (17) adjacent to said second main face (10).
Head (1) according to claim 3, characterized by the fact that said storage surface (21) has a substantially frusto-conical shape and is symmetrical to said central axis (5).
Head (1) according to any of the preceding claims, characterized by the fact that said introduction pipe (16) crosses said storage surface (21) and has a first extremity (26) associated with said attachment element (2) and a second extremity (27) associated with said second main face (10).
Head (1) according to claim 5, characterized by the fact that it comprises a through central hole (30) and crossing said plate-shaped body (7) between said first main face (8) and said second main face (10), said central hole (30) being arranged substantially mating said second extremity (27).
Head (1) according to one or more of the preceding claims, characterized by the fact that said extraction pipe (15) has a first portion (22) for the inlet of said excavated material (17) arranged on said first main face (8) and a second portion (23) for the discharge of said excavated material (17) arranged above said storage surface (21).
Head (1) according to claim 7, characterized by the fact that said second portion (23) has a diffuser element (25) able to spread said excavated material (17) on said storage surface (21).
Head (1) according to claim 8, characterized by the fact that said diffuser element (25) is directed in a radial manner with respect to said central axis (5).
Head (1) according to one or more of the preceding claims, characterized by the fact that said suction means (14, 15, 16) comprise a plurality of said extraction pipes (15) arranged symmetrically with respect to said central axis (5).
Head (1) according to one or more of the preceding claims, characterized by the fact that it comprises a plurality of said excavation tools (11), each of which is housed at least in part within a housing seat (12) formed in said plate-shaped body (7).
Excavating method, characterized by the fact that it comprises the steps of:
a) providing an excavating head (1) according to one or more of the preceding claims;

b) excavating the soil by means of said excavating head (1) to obtain a vertical excavation (31), the excavated material (17) being collected in said storage chamber (14);

c) extracting said excavating head (1) from said vertical excavation (31);

d) discharging the excavated material (17) from said storage chamber (14) on a surface outside of said vertical excavation (31);

e) repeating steps from b) to d) until reaching a predetermined depth.