Percussion drilling device

Abstract

A percussion drilling device for drilling in earth includes at least one housing section for a main piston, and a ring insert arranged in the housing section in front of the main piston so that the ring insert transmits at least part of the energy of the main piston onto the housing. The ring insert is attached to the housing by a shrink-fit connection.

Claims

1. A percussion drilling device for drilling in earth, comprising: at least one housing section for a main piston; and a ring insert arranged in the housing section in front of the main piston, and attached to the housing section by a shrink-fit connection, wherein the ring insert is arranged one of: (1) around an adjacent end of a drilling head tip configured to be directly impacted by the main piston when the main piston is driven in the forward direction, or (2) forward of a shoulder defined at one end by an anvil end of the drilling head tip, the shoulder configured to directly impact the ring insert, wherein the ring insert is configured to transmit at least part of the energy of the main piston onto the housing section.

2. The percussion drilling device according to claim 1, wherein: the housing section has an internal contour, wherein, when the housing section and the ring insert are at the same temperature, and the ring insert is external to the housing section, the internal contour of the housing section is smaller than an outer contour of the ring insert.

3. The percussion drilling device according to claim 1, wherein the housing section has a circular diameter.

4. The percussion drilling device according to claim 1, wherein the ring insert comprises an opening for the drilling head tip, and a base area defining a conically tapering, hollow space.

5. The percussion drilling device according to claim 1, wherein the ring insert is ring-shaped.

6. The percussion drilling device according to claim 1, wherein the ring insert is disposed at least in part in the housing section for the drilling head tip.

7. The percussion drilling device according to claim 1, wherein the ring insert is made of a first material, and the housing section is made of a second material different from the first material.

8. The percussion drilling device according to claim 1, wherein the ring insert is made of a heat treated material.

9. The percussion drilling device according to claim 1, wherein the ring insert is arranged around the adjacent end of the drilling head tip configured to be directly impacted by the main piston when the main piston is driven in the forward direction.

10. The percussion drilling device according to claim 1, wherein the ring insert is arranged forward of the shoulder defined at one end by the anvil end of the drilling head tip, the shoulder configured to directly impact the ring insert, wherein the ring insert is configured to transmit at least part of the energy of the main piston onto the housing section.

11. A method for the manufacture of a percussion drilling device for drilling in earth, comprising: inserting a ring insert in a housing section of the percussion drilling device, in front of a section for a main piston, and arranging the ring insert one of: (1) around an adjacent end of a drilling head tip configured to be directly impacted by the main piston when the main piston is driven in the forward direction, or (2) forward of a shoulder defined at one end by an anvil the end of the drilling head tip, the shoulder configured to directly impact the ring insert; and attaching the ring insert to the housing section by a shrink-fit connection, so that, responsive to forward motion of the main piston, the ring insert transmits at least part of the energy of the main piston onto the housing section.

12. The method for the manufacture of the percussion drilling device of claim 11, wherein attaching the ring insert to the housing section by the shrink-fit connection comprises generating a temperature difference between the ring insert and the housing section effective to cause at least one of a temporary increase in an internal diameter of the housing section, or a temporary reduction in size of an outer contour of the ring insert, sufficient to permit fitting of the ring insert into the housing section.

13. The method for the manufacture of the percussion drilling device of claim 12, wherein generating the temperature difference between the ring insert and the housing section comprises applying, to one or both of the ring insert or the housing section, heat or cold.

14. The method for the manufacture of the percussion drilling device of claim 11, wherein the ring insert is arranged around the adjacent end of the drilling head tip configured to be directly impacted by the main piston when the main piston is driven in the forward direction.

15. The method for the manufacture of the percussion drilling device of claim 11, wherein the ring insert is arranged forward of the shoulder defined at one end by the anvil end of the drilling head tip, the shoulder configured to directly impact the ring insert, wherein the ring insert is configured to transmit at least part of the energy of the main piston onto the housing section.

16. A percussion drilling device for drilling in earth, comprising: at least one housing section for a main piston; and a ring insert arranged in the housing section in front of the main piston, and attached to the housing section by a shrink-fit connection, wherein the ring insert is arranged one of: (1) around an end of a drilling head tip configured to be directly impacted by the main piston when the main piston is driven in the forward direction, or (2) forward of a shoulder at the end of the drilling head tip which is configured to directly impact the ring insert, wherein the ring insert is configured to transmit at least part of the energy of the main piston onto the housing section.

17. The percussion drilling device of claim 16, wherein: the housing section has an internal contour, wherein, when the housing section and the ring insert are at the same temperature, and the ring insert is external to the housing section, the internal contour of the housing section is smaller than an outer contour of the ring insert.

18. The percussion drilling device of claim 16, wherein the ring insert is made of a heat treated material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described in more detail by way of the exemplary embodiments shown in the drawings. Shown are in:

(2) FIG. 1 shows a front section of a percussion drilling device according to the invention in a cross-section of a side elevation of a first embodiment;

(3) FIG. 2 shows a front section of a percussion drilling device according to the invention in a cross-section of a side elevation of a second embodiment;

(4) FIG. 3 shows a front section of a percussion drilling device according to the invention in a cross-section of a side elevation of a third embodiment; and

(5) FIG. 4 shows a front section of a percussion drilling device according to the invention in a cross-section of a side elevation of a fourth embodiment.

DETAILED DESCRIPTION

(6) FIG. 1 depicts the front section of a percussion drilling device according to the invention in a cross-section of a side elevation. FIG. 1 depicts a first embodiment. The percussion drilling device is provided in this section with a housing 1 in which a main piston 2 is supported in a manner allowing it to oscillate. The main piston 2 is brought into an oscillating movement in a manner known per se using compressed air, which is supplied to the percussion drilling device at its rear end (not shown) via a compressed air line, where the percussion drilling device, in operation, impacts in every cycle of its movement a front striking surface.

(7) The percussion drilling device shown in FIG. 1 is a percussion drilling device that operates according to the two-stroke principle. The main piston 2 impacts in two stages, initially on a drilling head tip 3, which is designed as a chisel, and then on an insert or ring insert 4 respectively inside housing 1. The drilling head tip 3 is axially supported inside the drilling head 5 in a moveable manner, independent from the housing 1. One end of the drilling head tip 3 extends through a reduced cross-section inside the section of the housing 1 that is formed by the ring insert 4. The ring insert 4 comprises the impact surface for the main piston 2. The impact surface is designed as the base area of a conically tapered, hollow space inside ring insert 4.

(8) In the section with the ring insert 4 the housing 1 is designed to have a circular inner contour with an internal diameter. The ring insert 4 is provided with a circular outer contour with an external diameter. The external diameter of ring insert 4 is slightly larger than the internal diameter of the housing 1 provided that ring insert 4 and housing 1 are at the same temperature when located in the section under consideration. To be able to fit the ring insert 4 into the housing 1, the housing 1 may have been heated up and/or the ring insert 4 may have been cooled down. In this manner it is possible to fit the ring insert 4 in the desired position in housing 1. After cooling down and heating up respectively of the housing 1 and the ring insert 4 respectively to the same temperature, the ring insert 4 is fixed in position inside housing 1.

(9) The drilling head 5 may correspond to the drilling head of a percussion drilling device disclosed in WO 2011/128045 A2. In this respect reference is made to WO 2011/128045 A2 in its entirety.

(10) FIG. 2 depicts an alternative embodiment with a drilling head 5 inserted into the end of housing 1, wherein said drilling head 5 is provided with an insert or ring insert 4 respectively, which was fitted into the housing 1 to reduce the cross-section and to form an impact surface for the main piston. The ring insert 4 was fitted into the end section of housing 1 by way of shrink-fitting. One end of the drilling head tip 3 extends through the ring insert 4. The drilling head tip 3 is guided at the end and is provided with an impact surface for the main piston 2. The embodiment shown in FIG. 2 operates according to the one-stroke principle.

(11) FIG. 3 shows an alternative embodiment in which a ring insert 4, which is part of drilling head 5, has been inserted into the end of housing 1. The ring insert 4 of FIG. 3 is the end section of a front housing or drilling head 5 respectively, which was shrink-fitted and which comprises an axially supported, moveable drilling head tip 3 that moves independent from housing 1. The embodiment depicted in FIG. 3 operates according to the two-stroke principle. The ring insert 4 and the drilling head tip 3 are each provided with an impact surface for the main piston 2 onto which the main piston 2 impacts consecutively in a forward movement. Concerning the design of the drilling head 5 of the embodiment shown in FIG. 3, reference is made in this respect to WO 2011/128045 A2 in its entirety.

(12) FIG. 4 depicts an alternative embodiment in which a ring insert 4, which is part of drilling head 5, has been inserted into the end of housing 1. The ring insert 4 of FIG. 4 is the end section of a front housing or drilling head 5 respectively, which was shrink-fitted and which comprises an axially supported, moveable drilling head tip 3 that moves independent from housing 1. A compression spring is disposed between the drilling head tip 3 and the ring insert 4, which is compressed when the main piston 2 impacts on the drilling head tip 3. The drilling head tip 3 comprises an impact surface for the main piston 2. As a result of the impact by the main piston 2 on the drilling head tip 3, the drilling head tip 3 may impact on ring insert 4 after the spring located between the drilling head tip 3 and the ring insert 4 has been partially compressed. The embodiment depicted in FIG. 4 operates according to the two-stroke principle. The main piston 2 impacts first on the drilling head tip 3. After a sufficient compression of the spring, the drilling head 3 impacts on the ring insert 4 due to the impulse transmitted by the main piston 2.