FR2495203A1 - Pick for earth cutter - has tip for use on leading edge with additional tips behind and covered with soft material - Google Patents

Abstract

The cutter pick for use in earth cutting apparatus has one cutting tip (2) exposed ready for use on a leading edge (4) of the pick body (1). One or more additional cutting tips (3) are also located in the leading edge though spaced from the first cutting tip and each other. Preferably these additional cutting tips are protected by a layer (9) of material softer than the tips. Thus, as the first cutting tip is worn away, the pick body wears away to expose the next tip, so extending the pick life.

Description

 The invention relates to an improved drill bit for use on an excavator for digging various types of soil.

 More particularly, the invention relates to a drilling peak which can be removably mounted on a drilling wheel digging excavations in the ground or at the bottom of the sea.

 These drilling peaks generally comprise a body in which is embedded a drilling point made of tungsten carbide, this body being made of a material which is less hard than the drilling point. After a certain period of use the drill tips wear out and dislodge from their embedding in the pick body which then wears out very quickly. When this occurs on a particular drilling peak, this results in additional work for the neighboring peaks which then wear out even faster and which therefore have to be replaced after a very short time. This can be done by replacing the picks individually or by replacing the entire drill wheel with a new drill wheel.

 In any case, the operation wastes time and is therefore expensive, in particular when the excavator has to be raised from the bottom of the sea to repair it.

 The object of the invention is to overcome these drawbacks by creating a drilling peak which does not need to be replaced as often as the peaks according to the prior art, thereby reducing the frequency of loss of time for repairs to the excavator. .

 To this end, the invention relates to a drill bit intended for use on an excavator, drill bit characterized in that it comprises a body of the pick to which at least two drill points are attached, the first drill point being disengaged and protected to be used on the leading edge of the pick body, and the second drilling tip, or the following, being housed at regular intervals from one another in the leading edge of the pick body, a certain distance from the drill point.

 We thus use the fact that when a drill point is worn and detaches from the pick body, this pick body itself wears enough to release the next drill tip which in turn functions like the drill tip previous to extend the life of the peak.

Depending on the number of drill tips used, the life of the pick can be increased at will, thereby reducing the number of time lost for repairs, as was the case in the prior art.

 In practice, two drill tips are preferably used per peak.

 It is preferable that the second or subsequent drill tips are protected by a material welded to the pick body and shaped according to the initial shape of this pick, this material being less hard than that of the drill tips which are preferably made of carbide. of tungsten. This protection is necessary because the second or the next drilling point may be damaged by the secondary drilling effect, that is to say the drilling or the disaggregation of materials already cut and being trapped between the peak and the face of job.

The invention will be better understood on reading the following detailed description of an exemplary embodiment shown in the accompanying drawings, in which
FIG. 1 is a front view of a preferred embodiment of a drill peak according to the invention and
- Figure 2 is a side view of the peak of Figure 1.

 The drilling peak illustrated in the figures essentially comprises a peak body generally identified by the reference 1, as well as a first drilling point 2 and a second drilling point 3. Although no representation has been made here as two drill points 2 and 3, it is also possible to use other additional drill points regularly spaced on the leading edge 4.

 The pick body 1 comprises a connecting part 5 and a working part 6. The connecting part 5 makes it possible to mount the pick, removably, on the periphery of a drilling wheel (not shown) for example.

 The working part 6 has a leading edge 4 at one end of which the first drilling tip 2 is fixed.

 This first drilling point is housed in a cell 7 of the leading edge 4 and the second drilling point 3 is housed in a second cell 8 of the leading base 4, this second cell 8 being placed at a certain distance from the first cell 7. The second drill point 3 is of general trapezoidal section. In addition, as can be seen in FIG. 2, the complementary shape of the cell 8 and suitable welding means make it possible to fix this point 3 securely in the cell 8 until it is necessary to use it.

 To reduce the risk of damage to the second drilling tip 3 by secondary drilling effects, when it is not in use, the exposed part of the working surface of this cutting tip 3 is covered with a layer of protection 9. This protective layer is formed from a material that is not as hard as the drill point itself, and follows the general shape of the profile of the pick.

 Thus the shocks due to the effects of secondary drilling, that is to say to the materials already drilled or disaggregated which are trapped between the leading edge 4 and the face being drilled, no longer risk damaging the second point. drilling. Preferably the drill points are made of tungsten carbide, although other suitable materials can also be used.

 During operation, it is first of all the first drilling tip 2 which is in service on the working face. However, when this first drill point is worn to the point of falling, the pick body is eroded in the zone 10. Possibly the remains of the drill tip 2 are dislodged from the socket 7 and the pick body 6 is found eroded by the fact that the peak continues to function.

 This erosion of the peak body 6 continues until the second drilling point 3 is released, the protective layer 9 being very quickly eroded and the peak body 6 taking the shape indicated by the dotted line 11.

 The second drill point 3 then gives an additional life to the peak, and in fact doubles this life before replacement, compared to conventional peaks with a single drill point.

 The peak according to the invention thus makes it possible to reduce the frequency of idle repair time for the excavator, compared to the case where this excavator uses conventional peaks with a single drill point.

Claims (4)

 10) Drill bit intended to be used on an excavator, drill bit characterized in that it comprises a pick body (1) to which are fixed at least two drill points (2, 3), the first point of drilling (2) being released and ready to serve on the leading edge of the pick body (1) and the second drilling tip (3), or the following, being housed at regular intervals from one another in the edge d attack of the pick body (1), at a certain distance from the drill point (2).  20) Drill bit according to claim 1, characterized in that each of the drill points (3) or following, is housed in a cell (8) of the leading edge of the pick body (1).  30) A drill bit according to any one of claims 1 and 2, characterized in that each of the drill points (3) or following, is protected by a coating layer (9) made of a material less hard than that of the body of pic (1)  40) A drill bit according to any one of claims 1 to 3, characterized in that the material (9) is welded to the pick body (1) and shaped according to the initial shape of this pick body (1).  5) drill bit according to any one of claims 1 to 4, characterized in that the drill point (3) or following, have a generally trapezoidal zoidal section.