JPH0280785A - Vibrating core drill - Google Patents

Abstract

PURPOSE: To change the amplitude of vibration in correspondence with components of different characteristics by constituting a vibratory core drill free to change the position of the center of gravity of a rotor. CONSTITUTION: A variable amplitude rotor 10 is constituted of a rotor shaft 1, a half-cylindrical inside shell 2 and a half-cylindrical outside shell 3. This rotor 10 is built in an oil-filled housing 11 and installed in a bearing box 12 and is driven by cable driving through a connecting part 13 to be sealed from the housing by an oil sealing means 14. Thereafter, when a clamp 16 is fastened, the housing 11 is firmly installed on a drill string 15, vibration of the rotor 10 is transmitted to the drill string 15, and both of them are moved downward in a drilled hole. When a drill string of new length is added, the housing 11 is supported, the clamp 16 is loosened, the housing is made to slide up to the top part of new length, housing is fixed again at this position, and thereafter support is released.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable amplitude drill suitable for use as a vibratory drilling device for unconsolidated compositions such as soil, sand and gravel or for materials of this type.

[Conventional technology]

Vibratory drilling is a known technique in which the composition is penetrated by vibrating the drill without rotating it. Vibrations are generated by rotation of a wound or unbalanced rotor. According to this, the core can be collected with minimal variation from the initial state of the core. A drill point called a shoe, which forms a cutting edge, is attached to the lower end of the drill string. The female fitting is generally formed into a hollow conical shape with a smooth tapered outer wall surface. The frequency of the vibrations often reaches the sonic range, in which case the technique is called sonic drilling.

GB 21521008 discloses a vibratory core drilling device. This device has a housing; an eccentric member is rotatably mounted within the housing and vibrates the device when rotated about its rotational axis, and the eccentric member has an oil reservoir for the eccentric member. the core drill is fluid-tightly housed within a hollow space within the housing forming: means for coupling a rotational drive source to the eccentric member for rotating the eccentric member; and the longitudinal axis of the core drill rotates the eccentric member. Means are provided for connecting the body of the core drill to the housing so as to be set perpendicular to the axis.

Penetration is rapid in suitable compositions, but in areas to be cared or in layered compositions conditions are often encountered where penetration is slow or the drill is rejected altogether. . The causes of this rejection are: (1) the tube is filled with core material and vibrations are damped due to friction on the tube's inner surface; (2) friction between the tube's outer surface and the composition further oscillates. and [3) it becomes impossible to destroy the female fitting or the composition of its cutting edge, so that the female fitting detaches from the contact area and cannot allow forward movement of the tube.

The applicant's UK Patent No. 21.917864 discloses and claims a female fitting that is more effective than the previously described female fittings in overcoming these problems.

[Problem to be solved by the invention]

However, problems still remain, especially when drilling successive formations of different materials with different physical properties.

During drilling, the drill string vibrates in a complex manner with an amplitude determined by the eccentricity of the rotor. This vibration is transmitted to the female metal fitting, except when the female metal fitting happens to be located at a node of vibration. The vibrations may be damped to some extent by the composition through which the drill string and female fittings are drilled, but still remain to a greater or lesser extent.

A small perceptible vibration width is desirable to prevent the drill string from binding in the hole.

However, large amplitudes are undesirable.

This is because this substantially reduces the entrance area of the core sample to the female fittings that are common to the female fittings at each location. The smaller the amplitude of the female metal fitting, the larger the area ratio of the female metal fitting that is always open for the insertion of the core.

In loose materials such as flowing sand or gravel, the damping effect is less pronounced than in harder materials such as sandy soil or tar sand.

Thus, different conditions are required for different compositions. For loose materials, the original (i.e., unattenuated) amplitude is
It should be small. For stiff compositions, the original amplitude should be large since the relatively large damping effect of the composition will reduce the amplitude to the desired small amplitude.

[Means for solving problems and their effects] Motoyama p.
p developed a variable amplitude drill in which the amplitude of vibration can be varied in response to compositions of different properties.

This is achieved by making the rotor's center of gravity changeable.

According to the invention, the variable amplitude rotor comprises a housing connected to the drill string and a variable amplitude rotor mounted within the housing, the variable amplitude rotor having a central axis and an inner shell adjacent to the axis and an inner shell adjacent to the inner shell. A vibratory core drill is provided having an outer shell, the inner and outer shells being mutually rotatable and lockable and releasable in any desired relationship.

Preferably, both the inner and outer shells are configured in a semi-cylindrical shape.

\, The inner shell and the central shaft can be integrally formed with each other.

The housing can be mounted directly on top of the drill string, setting the axis of rotation of the rotor perpendicular to the axis of the drill string.

However, this shape may be suitable for simple drilling operations where a shallow core depth is required, or suffers from several disadvantages when large depth drillings are involved. One disadvantage is that the housing must be released and moved each time a longer drill string is added. Another disadvantage concerns core retrieval. In order to retrieve the core, the upper housing must be moved each time to get closer to the drill string 6.

These problems are avoided by mounting the housing on one side and passing the drill string through the housing through a clamp.

The shape obtained thereby is configured such that the axis of the drill string is vertically and the axis of the variable amplitude rotor is horizontally orthogonal. However, this is not an essential requirement, and the axis of the variable amplitude rotor can be set at an angle to the horizontal or even perpendicular.

The rotor can be driven by a flexible cable attached to a prime mover, such as an internal combustion engine, or it can be driven directly by the prime mover attached to the housing.

Preferably, both the inner and outer shells are of semi-cylindrical shape.

If both shells are configured in a semi-cylindrical shape, then for minimum amplitudes both shells are set in a minimum unbalanced position, ie in a position opposite each other. For maximum amplitude, both shells are set in the maximum unbalanced position, ie the inner shell rests within the outer shell. For intermediate amplitudes, both shells are set at a position midway between the extremes.

The drill can be suitably used for drilling core samples for determining the mineral content of the precipitate.

The drill can also be used for environmental investigations, as the core samples are subjected to measurement and analysis of the various degrees of contamination that occur.

〔Example〕

Next, the present invention will be described with reference to the accompanying drawings shown in FIGS. 1 to 4.

In FIG. 1, the variable amplitude rotor consists of a rotor shaft 1, a semi-cylindrical inner shell 2 and a semi-cylindrical outer shell 3.

Figure 1(a) is for the minimum amplitude of vibration, Figure 1(b)
shows the respective rotor configurations for intermediate amplitudes and FIG. 1 for maximum amplitudes.

In FIG. 2, which is shown schematically, the rotor assembly 4 is connected to a drill string 5, which is connected to a core drill drill bit 6. The maximum unbalanced vibration is shown by line 7 and the reduced unbalanced vibration by line 8. The variable vibration amplitude is shown by line 9.

The horizontal and vertical axes are drawn to the same scale, and amplitudes are greatly exaggerated to clarify features.

In FIGS. 3 and 4, a variable amplitude rotor 10 is housed within an oil-filled housing 11 and a bearing housing 12.
is mounted on top. The rotor 10 is driven by a cable drive (not shown) via a connection 13 that is sealed from the housing by oil sealing means 14.

The housing 11 is clamped around the drill string 15 by pivot clamping means 16.

When the clamp 16 is tightened, the housing 11 is firmly attached to the drill string 15.

The vibration of the rotor 10 is transmitted to the drill string 15,
Both of them are then moved towards His Excellency.

When adding a new length of drill string, support the housing 11, loosen the clamp 16 and slide the housing 11 to the top of the new length, and in this position re-secure the housing with the clamp 16 and then Release the support.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the variable amplitude rotor in three positions, Figure 2 is a diagram showing the vibration of the drill string, and Figure 3 is a diagram showing the vibration of the drill string.
The figure shows a plan view, partially in section, of a housing containing a variable amplitude rotor mounted offset on a drill string;
FIG. 4 is a perspective view of FIG. 3. 1... Rotor shaft 2... Inner shell 3.
...Outer shell 4...Rotor assembly 5...
・Drill string 6... Drill metal fitting 789... Line 10... Variable amplitude rotor 11... Housing 12... Bearing box 13... Connection part 14
... Oil sealing means 15 ... Drill string 16 ... Swivel clamp patent applicant: British Pitroleum Company

Claims (8)

[Claims] (1) A vibratory core drill having a housing (11) connecting a drill string (15), in which a variable amplitude rotor (10) is mounted in the housing (11), and the variable amplitude rotor (10) is connected to the central axis (1). an inner shell (2) adjacent to this axis (1) and this inner shell (2)
an outer shell (3) adjacent to the vibratory core drill, characterized in that the inner and outer shells (2) and (3) are mutually rotatable and lockable and releasable in any desired relationship. . 2. The vibratory core drill of claim 1, wherein the inner and outer shells (2) and (3) are semi-cylindrical in shape. (3) The vibratory core drill according to claim 1 or 2, wherein the inner shell (2) and the central shaft (1) are integral. (4) The housing (11) is the drill string (15)
4. A vibrating core drill according to claim 1, wherein the rotor (10) is mounted directly on top of the drill string, the axis of rotation of the rotor (10) being set at right angles to the axis of the drill string (15). (5) The housing (11) is the drill string (15)
The vibrating core drill according to any one of claims 1 to 3, wherein the vibrating core drill is mounted on one side. (6) The vibratory core drill according to claim 5, wherein the housing (11) is mounted offset in a direction perpendicular to the axis of the variable amplitude rotor (10) set horizontally. (7) The vibratory core drill according to claim 5, wherein the housing (11) is mounted offset with respect to the axis of the variable amplitude rotor (10) having an angle with respect to the horizontal direction. (8) The vibratory core drill according to claim 7, wherein the axis of the variable amplitude rotor (10) is vertical.