The present invention relates to a boring machine for boring a curvilinear hole in the earth.

Such a boring machine is known from WO 84/02951. The known boring machine is a tunnel boring machine for controlled boring of an elongated curvilinear tunnel in the earth. It comprises a cutter head for engaging a tunnel face and removing material therefrom to elongate the tunnel during repetitive cutting strokes. The cutter head is rotatably mounted to a cutter head support which can be moved with respect to a rear part of the boring machine by means of a hydraulic thrust cylinder. During a cutting stroke the thrust cylinder forces the cutter head against the tunnel face to provide cutting pressure. Between two successive cutting strokes the thrust cylinder is retracted for pulling the rear part towards the cutter head support in order to advance the rear part along the tunnel. Prior to starting a cutting stroke the rear part is positioned with respect to the tunnel by means of additional hydraulic cylinders between the rear part and the thrust cylinder before the rear part is temporarily anchored to the tunnel. During a cutting stroke the orientation of the cutter head support can be changed with respect to the rear part by hydraulic cylinders which are coupled to the cutter head support and exert a force between the cutter head support and the tunnel wall in transverse direction of the tunnel in order to create a curve in the tunnel.

The present invention aims to provide a simple boring machine . For this purpose the boring machine according to the invention comprises a cutter head, a cutter head support which supports the cutter head and a rear part which is provided with movable rear part grippers for temporarily fixing the rear part with respect to its surroundings, wherein the cutter head and the rear part are located at opposite sides of the cutter head support and the cutter head is rotatable with respect to the cutter head support about an axis of rotation, wherein the cutter head support and the rear part are coupled to each other by a thrust mechanism and a hinge including a single pivot point, wherein the hinge is translatable with respect to one of the cutter head support and the rear part along an axis of translation which extends through the pivot point and has at least a component that coincides with the axis of rotation, wherein the thrust mechanism drivably engages at least one of the cutter head support and the rear part at a distance from the axis of rotation and the axis of translation, respectively.

The thrust mechanism, which forms a coupling between the rear part and the cutter head support, allows to translate the hinge with respect to the one of the cutter head support and the rear part along the axis of translation as well as to change the orientation of the cutter head support with respect to the rear part about the pivot point at the same time, which provides a simple boring machine. Furthermore, the thrust mechanism can be entirely located between the rear part and the cutting head support, which provides a compact boring machine.

The boring machine may be a vertical boring machine which is intended for drilling a vertical hole, for example for offshore applications. It can be used as an alternative foundation technique to piling in hard soil which may contain boulders or rocks. The boring machine is also suitable for mining applications, for example for creating ventilation shafts in mining. The hinge including the single pivot point allows steering of the cutter head to counteract geological faults such as boulders or the like, or drifts from the boring process itself and/or to enable predefined curves in a bored hole. Hence, the boring machine enables to bore a curvilinear hole.

In practice the hinge can be translatable with respect to one of the cutter head support and the rear part along a centreline of the one of the cutter head support and the rear part, respectively. The centreline of the cutter head support may coincide with the axis of rotation.

It is noted that the axis of translation and the axis of rotation coincide when the hole to be bored is linear.

The hinge may have a fixed position with respect to the other one of the cutter head support and the rear part.

In a practical embodiment the hinge comprises a spherical bearing.

In a particular embodiment the spherical bearing has an inner part including a convex outside surface and a cooperating outer part including a concave inside surface, wherein the outer part is mounted to the one of the cutter head support and the rear part and translatable with respect to the one of the cutter head support and the rear part whereas the inner part is fixed to the other one of the cutter head support and the rear part.

In a preferred embodiment the inner part forms an inner ring and the outer part forms an outer ring which surrounds the inner ring, since this allows to use space within the inner ring for applying further components.

The boring machine may be provided with a torque transfer member including opposite ends which are fixed to the rear part and the cutter head support, respectively, wherein the torque transfer member is provided with a joint having a single pivot point which coincides with the pivot point of the hinge, and wherein a portion of the torque transfer member between the pivot point of the joint and the one of the cutter head support and the rear part is extendable along the axis of translation and locked in rotational direction thereof. An advantage of the torque transfer member is that a counter torque caused by the cutter head onto the cutter head support is transferred to the rear part through the torque transfer member rather than via the thrust mechanism. Hence, the thrust mechanism can be designed for translating the hinge and rotating the cutting head support and the rear part with respect to each other only.

In the event that the inner part forms an inner ring and the outer part forms an outer ring of the spherical bearing the inner ring may surround the joint.

The joint may be a universal joint, which is a simple but robust joint to transfer torque.

The torque transfer member may comprise a shaft and if it is provided with the universal joint it may be a cardan shaft.

In a particular embodiment the thrust mechanism comprises a plurality of linear actuators which are located at angular distance from each other about the axis of translation and the axis of rotation, wherein each of the linear actuators is operable independently along a line which has at least a component that is parallel to at least one of the axis of translation and the axis of rotation. The linear actuators may be located at equiangular distance from each other about the axis of translation and the axis of rotation. The linear actuators may be fixed at equiangular distance to the rear part about the axis of translation and at equiangular distance to the cutter head support about the axis of rotation. The linear actuators may be hydraulic cylinders.

In a specific embodiment the hinge is translatable with respect to the rear part along the axis of translation and has a fixed position with respect to the cutter head support.

In case of the presence of the spherical bearing the outer part may be fixed to a sleeve which is slidable on an outer side of the rear part.

Preferably, the sleeve surrounds the thrust mechanism so as to form a shield against the environment.

The cutter head support may be provided with a driving device for driving the cutter head.

In a particular embodiment the driving device comprises a plurality of electric motors which are drivably coupled to the cutter head through a transmission.

The cutter head support may be provided with movable cutter head support grippers for temporarily fixing the cutter head support with respect to its surroundings.

The invention will hereafter be elucidated with reference to the schematic drawings showing an embodiment of the invention by way of example.

Fig. 1 is a perspective view of an embodiment of a boring machine according to the invention.

Fig. 2 is a perspective view of a cutter head for the boring machine of Fig. 1 on a larger scale.

Fig. 3 is a sectional view of Fig. 1.

Figs. 4, 5 and 6 are enlarged views of details of Fig. 3 which are indicated in Fig. 3 by IV, V and VI, respectively .

Fig. 7 is a cross-sectional view of the boring machine as shown in Fig. 1, illustrating a different situation. Fig. 1 shows an embodiment of a boring machine 1 for boring a hole in the earth. The boring machine 1 is a vertical boring machine which is intended for drilling a vertical hole in the earth, but it can also be applied for boring a horizontal tunnel.

The boring machine 1 is elongated and has a cylindrical shape. It comprises a cutter head 2, which is shown in Fig. 2, and a cutter head support 3 which supports the cutter head 2 at a lower side of the cutter head support 3. Figs. 3-7 show further details of the boring machine 1. For explanatory reasons Fig. 1 and Figs. 3-7 do not show the cutter head 2. The cutter head 2 is rotatable with respect to the cutter head support 3 about an axis of rotation 4, which is indicated in Fig. 7. The cutter head support 3 comprises a driving device in the form of a plurality of electric motors 5 for driving the cutter head 2 through a gear transmission when the cutter head 2 is mounted to the cutter head support 3.

The boring machine 1 comprises a rear part 6 which is located at an upper side of the cutter head support 3 that is opposite to its lower side. Hence, the cutter head support 3 is located between the rear part 6 and the cutter head 2. The rear part 6 is provided with movable rear part grippers 7. The rear part grippers 7 are movable with respect to the rear part 6 in longitudinal direction thereof through inclinations such that their outer sides can move in radial direction of the rear part 6. During a boring action the rear part grippers 7 can temporarily fix the rear part 6 with respect to the surrounding walls of a hole. This prevents the rear part 6 from rotating within the hole in response to driving the cutter head 2; the rear part grippers 7 also counteract thrust produced during a cutting stroke. The rear part 6 may also contain auxiliary devices such as a slurry transportation pump and an electrical and hydraulic control system. The rear part 6 and the cutter head support 3 are coupled to each other by four independently controllable hydraulic cylinders 8, a spherical bearing 9 and a torque transfer member 10. The spherical bearing 9 comprises an inner ring 12 including a convex outside surface, a cooperating outer ring 13 including a concave inside surface, which outer ring 13 surrounds the inner ring 12, and a single pivot point 11 about which the rear part 6 and the cutter head support 3 can rotate with respect to each other. The pivot point 11 lies at an intersection of the axis of rotation 4 and a centreline 14 of the rear part 6. In this case the centreline coincides with an axis of translation along which the spherical bearing 9 is translatable with respect to the rear part 6.

In the embodiment as shown in the figures the inner ring 12 is fixed to the cutter head support 3 and the outer ring 13 is mounted to the rear part 6 through a sleeve 15 which is fixed to the outer ring 13 and slidable with respect to the rear part 6 on an outer side thereof in a direction along its centreline 14. The sleeve 15 surrounds the hydraulic cylinders 8 and partly surrounds the rear part 6.

The hydraulic cylinders 8 are drivably mounted to the rear part 6 at equiangular distance from each other about the centreline 14 and to the cutter head support 3 at equiangular distance from each other about the axis of rotation 4. The hydraulic cylinders 8 extend at an outer side of the torque transfer member 10. They form a thrust mechanism for moving the hinge 9 with respect to the rear part 6 and to rotate the cutter head support 3 and the rear part 6 with respect to each other during a cutting stroke. This means that the axis of rotation 4 can be angled with respect to the centreline 14 of the rear part 6. In the situation as shown in Figs. 1 and 3 the centreline 14 of the rear part 6 and the axis of rotation 4 coincide and in the situation as shown in Fig. 7 the centreline 14 of the rear part 6 and the axis of rotation 4 are angled with respect to each other. In the latter situation the hole to be bored will be curved and in the former situation the hole to be bored will be linear. The centreline 14 always has a component that coincides with the axis of rotation 4. In general terms each of the hydraulic cylinders 8 is operable along a line which has at least a component that is parallel to at least one of the axis of translation 14 and the axis of rotation 4. In order to allow the tilting movement between the rear part 6 and the cutting head support 3 the hydraulic cylinders 8 are mounted to the rear part 6 and the cutter head support 3 through respective ball joints.

The torque transfer member 10 has a centreline which coincides with the centreline 14 of the rear part 6, a lower end 10a which is fixed to the cutter head support 3 and an upper end 10b which is fixed to the rear part 6. The torque transfer member 10 is also provided with a universal joint 16 which has a pivot point that coincides with the pivot point 11 of the spherical bearing 9. A portion of the torque transfer member 10 which comprises the universal joint 16 is surrounded by the inner ring 12. A portion of the torque transfer member 10 which extends between the pivot point 11 and its upper end 10b is telescopically extendable in a direction along the centreline 14 and locked in rotational direction about the centreline 14, for example through splines. This means that during a boring action a counter torque caused by the electric motors 5 onto the cutter head support 3 is transferred to the rear part 6 through the torque transfer member 10 rather than via the hydraulic cylinders 8.

The cutter head support 3 is provided with cutter head support grippers 17, which are movable with respect to the cutter head support 3 in radial direction of the axis of rotation 4. The vertical boring machine 1 may be applied as follows. First, when the boring machine 1 is positioned such that the cutter head 8 faces an end wall of a hole to be elongated and the hydraulic cylinders 8 are in their retracted positions the rear part grippers 7 are extended to fix the rear part 6 to its surroundings, after which the electric motors 5 are switched-on and the hydraulic cylinders 8 start to exert a force onto the cutter head support 3 so as to perform a cutting stroke. The hydraulic cylinders 8 can be operated such that during a cutting stroke they exert an eccentric thrust such that the direction of cutting is angled with respect to the axis of translation 14 in order to create a curved hole. After reaching a certain extension of the hydraulic cylinders 8 the electric motors 5 are switched-off and the rear part grippers 7 are retracted, whereas the cutter head support grippers 17 are extended to fix the cutter head support 3 to its surroundings. Subsequently, the hydraulic cylinders 8 are retracted such that the rear part 6 moves towards the cutter head support 3. After retracting the cutter head support grippers 17 a next cutting stroke as described hereinbefore can be performed. During a cutting stroke the excavated materials can be transported upwardly through a discharge pipe 18 which may be part of a Multiport Rotary union (not shown). The Multiport Rotary union, which is also called a Multiport-swivel or Multiport joint, can be used for transporting supplied and discharged media between swivelling parts in an appropriate manner, in this case between the cutting head support 3 and the rear part 6 of the boring machine 1. The supplied and discharged media are transported in different passages that are strictly separated from each other by seals. Examples of supply lines for supplied media in the boring machine 1 are hydraulic lines and water lines and an example of a discharge line for discharged media is a slurry line for discharging slurry or a mixture of water and excavated materials. The application of the Multiport Rotary union is advantageous since it does not use clamps or crimp sleeves to secure the fitting into the hose and it saves assembly time.

The invention is not limited to the embodiment shown in the drawings and described hereinbefore, which may be varied in different manners within the scope of the claims and the technical equivalents. For example, the spherical bearing may be replaced by an alternative hinge including a single pivot point, the universal joint at the torque transfer member may be replaced by an alternative joint including a single pivot point or the hinge may be translatable with respect to the cutter head support and fixed to the rear part.