The present invention relates to the technical sector concerning the realising of holes on rocky terrain, for example for foundation poles for buildings, bridges, for pylons or walls. More in particular, the invention relates to a rock crushing for widening a pilot hole previously made on rocky terrain.
At present, to make a hole of a limited diameter on rocky terrain, a tool known as a “down the hole hammer” can be used. A down the hole hammer is a device comprising: a plurality of crushing buttons; and a crushing head which is provided with a plurality of seats, for receiving the crushing buttons so that the buttons project to contact the rock to be crushed, and which is provided with a plurality of channels for passage of the crushed rock externally of the hole under formation. During use, the down the hole hammer is: subjected to a vibratory motion along the axis thereof by means of compressed air; drawn in rotation with respect to the axis thereof; and advanced along the hole under formation as the rock is progressively crushed and is conveyed to the outside by the compressed air. The compressed air has the function of providing the vibratory motion of the down the hole hammer and of pushing the crushed rock towards the outside.
Each down the hole hammer is suitable for realising a hole having a predetermined diameter. Should it be necessary to make a hole having a different diameter, then it would also be necessary to obtain another down the hole hammer suitable for the different diameter.
This constitutes a drawback, as each device of the above-described type has a significant size and cost.
For holes of large dimensions, for example a diameter of greater than 1 metre, it becomes very expensive to use a single down the hole hammer having a diameter corresponding to that of the hole to be obtained, as well as requiring a great deal of space.
As an alternative, see
Whether using a single down the hole hammer or a main head provided with a plurality of down the hole hammers (in the case of a rock perforating unit), for activation thereof and expulsion of the crushed rock a high flow-rate of air is required. The air flow increases as the diameter of the hole to be made increases.
In cases where holes are to be made in places that are difficult to access, the transport of the single down the hole hammer or the rock crushing unit and compressors can become an issue.
Each rock perforating unit is suitable to realise a hole having a predetermined diameter. Should it be necessary to make a hole having a different diameter, then it would be necessary to obtain another rock perforating unit suitable for the different diameter.
To reduce the number of compressors necessary when one down the hole hammer is not sufficient to make the hole, a known practice is the following: a pilot hole is made with a single down the hole hammer, which is concentric to the hole to be made and has a smaller diameter than the hole to be made; thereafter, a rock crushing unit is used (also known as a hole opener, not illustrated) which differs from the one described in the foregoing due to the fact that the down the hole hammers it holds are only distributed along the periphery of the main head. This enables, given a same diameter of the hole to be made, the use of a smaller number of compressors. However, this is only a partial solution to the above-described drawbacks.
To summarise, in order to realise large-diameter holes, i.e. in a range going from 6′ to 10′ (1800-3000 mm), a single down the hole hammer could be used, or a rock perforating unit, having a plurality of down the hole hammers. Both the solutions would have the following drawbacks: the compressors would be in a high number, which would lead to problems of space in the worksite, transport and cost; the down the hole hammers would be expensive and might make only one hole of the predetermined diameter.
Alternatively, hole openers could be used, which can be activated by a smaller number of compressors, but which however have the following drawbacks: they are expensive; they are usable for a predetermined diameter; they are less productive with respect to a single down the hole hammer.
The aim of the present invention consists in finding a solution which enables obtaining holes of different diameter and which does not require the use of compressors.
The aim is attained with a rock crushing unit according to claim 1 or claim 2 and by means of a rock crushing method according to claim 15.
The pilot hole can be realised for example with only one down the hole hammer. Thereafter the unit or the rock crushing method of the invention can be used, which enables progressive widening of the pilot hole up to a desired diameter: this is advantageous due to the fact that it is possible to obtain holes of different diameters, while in the prior art it was necessary to have recourse to a plurality of different rock crushing units (one for each hole diameter that was to be obtained, see
A further advantage consists in the fact that the rock crushing unit or method of the invention does not require the use, in order to function, of down the hole hammers, and therefore does not require a plurality of compressors for the air.
The rock crushing unit of claim 1 comprises a first plurality of arms which are arranged in such a way that the reaction forces mutually compensate: for this reason the stabilising means are not included, as they are not considered essential. The stabilising means are however preferable if the rocky terrain is not homogeneous.
The rock crushing unit of claim 2 comprises at least one arm and stabilising means: in a case where one arm only is included, the stabilising means are therefore essential to maintain the main body centred with respect to the axis of the pilot hole during the use of the rock crushing unit.
The forces crushing the rock are advantageously comparable to those obtainable with down the hole hammers, but without the need to use compressed air.
Specific embodiments of the invention will be described in the following part of the present description, according to what is set down in the claims and with the aid of the appended tables of drawings, in which:
In the following, reference will be made to figures from 2 onwards.
A rock crushing unit (1) for widening a pilot hole (3) realised on rocky terrain (4) is described according to a first invention and a second invention.
The rock crushing unit (1) according to the first invention comprises: a main body (2) (see
In other words, when the arms of the first plurality of arms (51) are in the extended position (E), then they project more greatly from the main body (2) with respect to when they are in the retracted position (R).
The pilot hole (3) is a hole that has been made previously on rocky terrain (4) using known modalities, see
The rotation velocity of the main body (2) can be 20 revolutions per minute and the modalities for drawing the main body (2) in rotation are generally of known type.
When the arms of the first plurality of arms (51) are in a retracted position (R), the main body (2) can be inserted in the pilot hole (3).
The crushing elements of the first plurality of crushing elements (21) can comprise roller bits,
These crushing elements of the first plurality of crushing elements (21) can comprise cutter discs (
These crushing elements of the first plurality of crushing elements (21) can comprise crushing rollers, not illustrated: a crushing roller comprises a cylindrical portion provided with crushing buttons. Each crushing roller is preferably arranged so that the relative axis is parallel to the axis of the pilot hole (3).
The rock crushing unit (1) can also comprise a second plurality of crushing elements (22) for crushing rock, each of which is borne by an arm of the first plurality of arms (51) and is arranged in order to be able to press against the lateral wall of the pilot hole (3) during use of the rock crushing unit (1). These crushing elements of the second plurality of crushing elements (22) can comprise rock picks, see
Each crushing element (21) of the first plurality of crushing elements is preferably rotoidally coupled to a corresponding arm of the first plurality of arms (51), and is thus free to rotate with respect to an axis thereof.
In accordance with a first embodiment of the rock crushing unit (1), each arm of the first plurality of arms (51) comprises a rod (6) (
If the hydraulic cylinders are two in number, they can be arranged at 180° from one another; if the hydraulic cylinders are three in number, they can be arranged at 120° to one another; if the hydraulic cylinders are four in number, they can be arranged at 90° to one another; and so on.
In the case illustrated in the figures of the drawings, the rock crushing unit (1) comprises a first pair of hydraulic cylinders (31) which is arranged at a first height and a second pair of hydraulic cylinders (32) , which is arranged at a second height: the hydraulic cylinders of each pair of hydraulic cylinders are however arranged opposite one another, i.e. arranged at an angle of 180°.
When the crushing elements of the first plurality of crushing elements (21) (or the crushing element, if only one is provided) borne by a rod (6) of a hydraulic cylinder of the plurality of hydraulic cylinders (55) press against the lateral wall of the pilot hole (3) then a corresponding reaction force is generated, in an opposite direction: the fact that the cylinders of the plurality of hydraulic cylinders (55) are angularly equidistanced from one another is advantageous, as the reaction forces generated by the rods (6) of each cylinder of the plurality of hydraulic cylinders (55) thus tend to reciprocally compensate.
The hydraulic cylinders of the plurality of hydraulic cylinders (55) are preferably double-acting, so that the return of the rods (6) of the hydraulic cylinders is easy once the pilot hole (3) has been widened.
Once the rock crushing unit (1) has widened the pilot hole (3) where the crushing elements of the first plurality of crushing elements (21) have been active (see
Each arm of the first plurality of arms (51) can comprise (
To further widen to the pilot hole (3) from the first diameter to a second diameter which is greater than the first diameter,
At least a part of the crushing elements (see
For example, a rod (6) of a first hydraulic cylinder of the plurality of hydraulic cylinders (55) can bear a first crushing element (41), a second crushing element (42) and a third crushing element (43), while the rod (6) of a second hydraulic cylinder of the plurality of hydraulic cylinders (55) can bear a fourth crushing element (44), a fifth crushing element (45) and a sixth crushing element (46). All of these crushing elements are arranged at staggered and consecutive heights to one another, in the sense that: the first crushing element (41) is higher than the fourth crushing element (44); the fourth crushing element (44) is higher than the second crushing element (42); the second crushing element (42) is higher than the fifth crushing element (45); the fifth crushing element (45) is higher than the third crushing element (43); the third crushing element (43) is higher than the sixth crushing element (46) (see
The rock crushing unit (1) preferably comprises stabilising means (9) borne by the main body (2), and which are configured to be able to abut the lateral wall of the pilot hole (3) with the aim of keeping the main body (2) centred with respect to the axis of the pilot hole (3) during use of the rock crushing unit (1).
The stabilising means (9) have advantageously been designed to exploit the pilot hole (3) as a centring guide of the main body (2).
The stabilising means (9) preferably comprise a cylindrical body (10) which is dimensioned so as to insert in the pilot hole (3) and to abut the lateral wall of the pilot hole (3). Still more preferably, the cylindrical body (10) is a basket (10) for collection of rocky material which is arranged inferiorly of the first plurality of crushing elements (21) and which comprises at least an opening (12) so as to internally receive the rocky material which is progressively removed from the lateral wall of the pilot hole (3). Therefore the rock crushing unit (1) must be periodically withdrawn from the pilot hole (3) in order to unload the rocky material present in the basket (10).
Alternatively, the stabilising means (9) comprise, instead of the above-described basket (10), a plurality of abutments (13) for abutting the lateral wall of the pilot hole (3): the distance of the plurality of abutments (13) from the axis of the main body (2) is adjustable so as to adapt the stabilising means (9) to different diameters of the pilot hole (3). In this regard, see
The stabilising means (9) preferably comprise a second plurality of arms (52) which are arranged radially, which are telescopic and which bear the abutments of the plurality of abutments (13). Each abutment of the plurality of abutments (13) is preferably arranged at the free end of an arm of the second plurality of arms (52). The abutments of the plurality of abutments (13) are preferably angularly equidistanced to one another. The abutments of the plurality of abutments (13) are preferably plates; these plates can be arched (
The stabilising means (9) are preferably rotatable and borne by the main body (2). During the use of the rock crushing unit (1), the rocky material which is progressively crushed can be not uniform, with the consequence that the main body (2) tends to displace from the axis of the pilot hole (3) towards the area of rocky material which is more easily crushed: to keep the main body (2) centred, the stabilising means (9) abut the pilot hole (3), generating friction. In such a circumstance, the stabilising means (9) are solidly constrained to the main body (2), then the friction generated by contact of the stabilising means (9) with the lateral wall of the pilot hole (3) gives rise to a resistant torque that is opposite to the activating torque of the main body (2). To prevent this drawback, the stabilising means (9) can advantageously be rotatable and borne by the main body (2), i.e. can be idle.
The rock crushing unit (1) preferably comprises deflecting means (14) (
The deflecting means (14) preferably comprise a plurality of blades (14). The blades of the plurality of blades (14) can be fixed to the lower walls of the arms of the first plurality of arms (51), for example by welding.
The rock crushing unit (1) preferably comprises a third plurality of arms (53) (
In a second embodiment of the rock crushing unit (1), illustrated in
The rock crushing unit (1) according to the second invention comprises: a main body (2) dimensioned so as to insert in a pilot hole (3) realised on rocky terrain (4) and activatable in rotation with respect to the axis thereof; first actuator means (5) which are borne by the main body (2) and which comprise a hydraulic cylinder (55, 63, 64); an arm (51) which is borne by the main body (2) and which is activatable by the hydraulic cylinder (55, 63, 64) in order to move between a retracted position (R) and an extended position (E) with a planar movement that is perpendicular to the axis of the main body (2); a first plurality of crushing elements (21) for crushing rock, each of which is borne by the arm, is rotatable with respect to the cited arm and is arranged in order to be able to press against, and roll along, the lateral wall of the pilot hole (3) during use of the rock crushing unit (1), i.e. when the main body (2) is inserted in the pilot hole (3) and is drawn in rotation with respect to the axis thereof and when the hydraulic cylinder (55, 63, 64) activates the arm so that it moves towards the extended position (E); stabilising means (9) borne by the main body (2) and which are configured to be able to abut the lateral wall of the pilot hole (3) with the aim of keeping the main body (2) centred with respect to the axis of the pilot hole (3) during use of the rock crushing unit (1); the rock crushing unit (1) being configured so that when in use, the action exerted by the crushing elements of the first plurality of crushing elements (21) on the lateral wall of the pilot hole (3) determines the crushing of the lateral wall of the pilot hole (3) and thus the widening of the pilot hole (3).
The first actuator means (5) preferably comprise a plurality of hydraulic cylinders (55, 63, 64); the rock crushing unit (1) comprises a first plurality of arms (51) which are borne by the main body (2) and which are activatable by the hydraulic cylinders of the plurality of hydraulic cylinders (55, 63, 64) in order each to move between a retracted position (R) and an extended position (E) with a planar movement which is perpendicular to the axis of the main body (2); each crushing element of the first plurality of crushing elements (21) is rotatable and borne by an arm of the first plurality of arms (51) and is arranged in order to be able to press against, and roll along, the lateral wall of the pilot hole (3) during use of the rock crushing unit (1), i.e. when the main body (2) is inserted in the pilot hole (3) and is drawn in rotation with respect to the axis thereof and when the hydraulic cylinders of the plurality of hydraulic cylinders (55, 63, 64) activate the first plurality of arms (51) so that they move towards the extended position (E).
All the considerations already elaborated for the first invention are also valid for the second invention.
A further aim of the present invention is rock crushing method for widening a pilot hole (3) realised on rocky terrain (4), comprising following steps: bringing a first plurality of crushing elements (21) to crush rock internally of a pilot hole (3) realised on rocky terrain (4); pressing the crushing elements of the first plurality of crushing elements (21) against the lateral wall of the pilot hole (3) and at the same time causing the crushing elements of the first plurality of crushing elements (21) to roll along a cylindrical portion of the lateral wall of the pilot hole (3), so that the action exerted by the crushing elements of the first plurality of crushing elements (21) on the lateral wall of the pilot hole (3) determines the crushing of the lateral wall of the pilot hole (3) and thus the widening of the pilot hole (3).
The hole obtained can have various shapes, for example cylindrical or conical.
The method preferably includes repeating the previous steps, taking the first plurality of crushing elements (21) to different depths, so that overall a cylindrical volume of rocky material is removed.
The rock crushing unit (1) according to the first invention and the second invention is part of a rock crushing machine (80), see
The following is a description of the rock crushing unit (1) illustrated in
Thereafter,
Subsequently, the rock crushing unit (1) is lowered to a further depth and the above-described cycle is repeated.
In a case where the rods (6) of the hydraulic cylinders of the plurality of hydraulic cylinders (55) are too short to obtain a desired final diameter of the pilot hole (3), then extensions (8) for the arms can be fitted, to be fixed to the rods (6) of the hydraulic cylinders of the plurality of hydraulic cylinders (55), see
In general terms, the second diameter (which is also a predetermined value) can be reached even when the rods (6) of the hydraulic cylinders of the plurality of hydraulic cylinders (55), on which the extensions (8) have been fitted, have reached a position comprised between the retracted position (R) and the extended position (E).
It is understood that the foregoing has been described by way of non-limiting example, and that any eventual constructional variations are understood to fall within the protective scope of the present technical solution, as claimed in the following.
Number | Date | Country | Kind |
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102019000003721 | Mar 2019 | IT | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IB2020/052369 | 3/16/2020 | WO | 00 |