DRILL DEVICE HAVING A ROTARY-VIBRATORY DRIVE

Drill device having a rotary-vibratory drive

BACKGROUND OF THE INVENTION

The invention relates to a drill device having a vibratory drive and a rotary drive, wherein the vibratory drive is connected to the drill string for providing a vibration to the drill string, and wherein the rotary drive is connected to the drill string for providing a rotation to the drill string.

Drill devices having rotary-vibratory drive are highly suitable for many purposes, among others for taking soil samples or for seismic research. Such drill devices usually use a mechanic vibrator comprising one or more rotating eccentric rollers. They provide the drill string with a substantially vertical vibration, which vibration usually is in the range of the sonic frequencies. Such a drill device is commonly called a sonic drill. Simultaneously with the vibration the drill pipes can be rotated by one or more motors.

Such a rotary-vibratory drill device is described in US patent 5,409,070. The drill device described in said US patent shows a vibratory drive unit connected to the drill string. The drill device is provided with a second coupling member that is connected to the drill string and provided with a number of spaced apart blade-shaped members, extending outwards from the drill string. Each blade-shaped member has opposite sides that are slidably received between a number of supports of first coupling members that are connected to the rotary drive. The first coupling members are provided with a number of spaced apart pairs of supports, wherein each support has a radially extending surface, wherein the surfaces of each pair of supports are spaced apart for receiving the blade-shaped member of the second coupling member therebetween. The blade shaped members are slidably received, particularly slidably in radial direction, between the pair of supports. In this way the vibration of the vibratory drive can be substantially uncoupled from the rotary drive.

A drawback of the rotary-vibratory drill device as described in US patent 5,409,070 is that the rotary drives have to be placed around the drill string, resulting in a complex structure.

It is an object of the invention to provide a rotary-vibratory drill device having an improved and preferably simplified coupling for connecting the rotary drive and the vibratory drive to the drill string.

SUMMARY OF THE INVENTION

According to a first aspect the invention provides a drill device according to the opening paragraph, wherein the vibratory drive is placed between the rotary drive and the drill string, and wherein a coupling is placed between the vibratory drive and the rotary drive, which coupling substantially prevents the passing on of vibrations from the vibratory drive to the rotary drive. Due to such a serial structure of the rotary drive, vibratory drive and drill string, a simple and highly reliable drill device can be achieved. The rotary drive is also effectively protected against the vibrations generated by the vibratory drive, which vibrations due to the coupling are substantially not passed on to the rotary drive. Because said vibrations are not passed on to the rotary drive a premature failure of the rotary drive can be substantially avoided.

It is noted that among others from US patent 3,517,754 and International patent application 98/58154 a drill string is known having a percussive device placed in the drill string. Such known percussive devices comprise a percussive hammer placed in the drill pipe and which is able to hammer against an end of a drill bit placed within the drill pipe. The drill bit is placed in such a way at the end of the drill pipe that faces away from the drive mechanism of the drill string, that the drill bit is able to move up and down with respect to the drill pipe. Such a drill bit is also referred to as "percussive drill bit" and such a percussive device is also referred to as "down hole percussive hammer".

Contrary to the invention the known percussive device will only exert an impact force on the drill bit, wherein the impact will not be passed on to the drill pipe by the movable drill bit. A vibratory drive does not only provide impact force but also a vibrating, particularly reciprocating, force which keeps the drill pipe substantially continuously in motion.

Contrary to the invention the known percussive device is placed in the drill string and the impact force is only exerted on the drill bit. In the device according to the invention the vibratory and rotary drive provides a vibration and/or rotation to the entire drill string, particularly the drill pipe. As a result the device according to the invention among others has the following advantages with respect to the devices discussed above:

1. By providing a vibration to the entire drill pipe, use can be made of a hollow drill pipe for achieving drill cores for studying the soil structure, particularly the soil layers present.

2. By providing a vibration to the entire drill pipe, when drilling a drill hole the friction between the soil and the drill pipe will be considerably reduced, as a result of which drilling can be carried out more rapidly. Moreover due to the vibration a possible adhesion between soil and drill pipe, preferably both internally and externally, can be substantially avoided. As a result soil samples can be taken that show a highly true- to-nature picture of the soil layers present.

In one embodiment the vibratory drive and the rotary drive are placed in a drive unit, for providing a vibration and/or rotation to a drive shaft, wherein at its upper side the drill string can be coupled to a drive shaft for passing on a rotation and/or vibration from the drive shaft to the drill string. When operative the drive unit is placed substantially above the drill hole, wherein the drill string extends from the drive unit into the drill hole. In one embodiment the drive unit can be coupled to an end of the drill string, preferably an aboveground end of the drill string. In one embodiment the vibratory drive is disposed on the drive shaft for, when operative, passing on a vibration that is substantially oriented along the drill string, to the drive shaft. In one embodiment an end of the drive shaft facing away from the drill string is connected to the coupling. In one embodiment the vibratory drive is placed between the coupling and the drill string, particularly the drill pipe.

In one embodiment the rotary drive is connected to the coupling by its drive shaft. The drive unit thus forms a connection in series of: a rotary drive that is rotation-fixedly connected to the coupling, subsequently a drive shaft that is substantially rotation-fixedly connected to the coupling, a vibratory drive that is placed on the drive shaft and which is adapted for providing a vibration to the rotatabie drive shaft, and a coupling device placed under the vibratory drive for coupling a drill string thereto, particularly a drill pipe.

In one embodiment the coupling comprises a first and a second coupling member placed coaxially with respect to each other, wherein the first coupling member comprises an internally toothed ring, or internal ring gear, and wherein the second coupling member comprises a toothed wheel, or gear wheel, wherein the teeth of the toothed wheel at least partially mesh with the toothed ring. In one embodiment the teeth of the toothed ring and of the toothed wheel extend substantially radially with respect to the centre line of the coupling. As a result the toothed wheel is able to perform a vibration in axial direction with respect to the toothed ring as a result of which a vibration from the first coupling member is not passed on to the second coupling member, or vice versa.

In one embodiment, at least in a circumferential direction, a space between the teeth of the toothed ring is larger than the thickness of the teeth of the toothed wheel. In that way the teeth of the toothed wheel are placed between the teeth of the toothed ring with a certain degree of clearance. Because of this clearance the teeth of the toothed wheel, when the rotary drive is not active, can be placed in a position, in which the teeth of the toothed wheel substantially do not exert forces on the teeth of the toothed ring. In particular the teeth of the toothed wheel can be placed in a spaced apart position between the teeth of the toothed ring. As a result, the rotary drive can be effectively uncoupled from the vibratory drive. Consequently, when the rotary drive is not active, the wear in the coupling will be strongly reduced or substantially prevented. Moreover the rotary drive is protected by said uncoupling, as a result of which wear and premature failure of the rotary drive can be substantially prevented.

In one embodiment the first and second coupling members are designed such that the teeth of the toothed wheel abut the teeth of the toothed ring at one side only, at least when the rotary drive is operative. Also in this embodiment the teeth of the toothed wheel are placed with clearance in the openings between the teeth of the toothed ring and advantages comparative to the ones described above are gained.

In one embodiment the first and second coupling members are made of different materials, wherein the first coupling member is made of a softer material than the second coupling member, or vice versa. For instance the coupling member that is made of the tougher material can be made of a tough ceramic material. In a further embodiment the first and second coupling members are made of different metals.

By making the coupling members of different materials or different metals, it can be substantially prevented that the first and second coupling members weld together due to the vibrations.

By making the one coupling member of a softer material or metal than the other coupling member, wear will substantially only occur in the coupling member made of the softer material. The coupling member of the softer material thus forms a wearing part that needs to be replaced regularly, whereas the other coupling member, of the tougher material or metal, needs to be replaced less often or not at all. In one embodiment the coupling member that is easiest to replace, is made of the soft material or metal. In one embodiment the coupling member of a softer metal is made of a metal having self-lubricating properties, such as for instance yellow brass, bronze or another alloy. Said self-lubricating property ensures a decrease in friction between both coupling members.

In one embodiment the coupling member of a tougher metal is made of steel or a steel alloy.

In one embodiment the coupling member of a tougher material is provided with a wear-indicator. In one embodiment the wear-indicator is rotation-fixedly connected to the coupling member of the tougher material, wherein the wear-indicator cooperates with a reference member that is rotation-fixedly connected to the coupling member of the softer material. When the coupling member of the softer material wears out, the wear-indicator will slide with respect to the reference member. Said sliding of the wear-indicator with respect to the reference member therefore is a degree of the wear of, particularly, the coupling member of the softer material.

In one embodiment the wear-indicator and the reference member have been visibly placed at the outside of the coupling. In this way the degree of wear of the coupling member of the softer material can easily be perceived at the outside. When the displacement of the wear- indicator with respect to the reference member has reached or exceeded a pre-determined threshold value, the coupling member of the softer material needs to be replaced.

In one preferred embodiment the first coupling member, with the internally toothed ring, is actively connected to the vibratory drive and the second coupling member, the toothed wheel, is actively connected to the rotary drive. In one embodiment the toothed wheel, particularly considered in axial direction, is placed entirely within the toothed ring.

In a further embodiment the toothed ring at its side facing the vibratory drive and facing the rotary drive, is provided with sealing means for forming a reservoir for placing a friction-reducing fluid therein. In this way the friction between the first and second coupling member can be further reduced. In one embodiment the friction-reducing fluid comprises a lubricant or oil.

Because the toothed ring is connected to the vibratory drive, the toothed ring at its side facing the vibratory drive, can be substantially provided with a bottom surface, as a result of which the toothed ring forms a bowl with its bottom surface for placing the friction-reducing fluid, such as the lubricant or the oil, therein.

According to a further aspect the invention provides a coupling to be placed between a vibratory drive and a rotary drive suitable and intended for a drill device as described above.

The aspects and measures described in this description and the claims of the application and/or shown in the drawing of this application may where possible also be used individually. Said individual aspects, such as the serial placing of the rotary drive, vibratory drive and drill string, the coupling device having first and second coupling members of different materials, wherein the one material is softer than the other material, and the use of the toothed ring with bottom surface for forming a reservoir for friction-reducing fluid, and other aspects may be the subject of divisional patent applications relating thereto. This particularly applies to the measures and aspects described per se in the sub claims.

SHORT DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of a number of exemplary embodiments shown in the attached drawings, in which:

Figure 1 shows a schematic view of an exemplary embodiment of a drill device according to the invention;

Figure 2 shows a first exemplary embodiment of a coupling member according to the invention in a disassembled condition;

Figure 3 shows a view of a coupling according to figure 2 in assembled condition; Figure 4 shows a view in cross-section along the line A-A of figure 3;

Figure 5 shows a view in longitudinal section along the line B-B of figure 3; and

Figure 6 shows a top view of the coupling according to a further embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 shows a schematic view of a drill device 1 according to the invention. The drill device comprises a drill string 5 having a drill pipe, which drill pipe at its upper side is coupled to a drive shaft 51. The coupling is such that a rotation and/or vibration of the drive shaft 51 is passed on to the drill string 5. A vibratory drive 4 is disposed on the drive shaft 51 , which vibratory drive, when operative, passes on a vibration that is oriented substantially along the drill string 5, to the drive shaft 51 . The upper part of the drive shaft 51 is connected to a coupling 3. Above the coupling 3 a rotary drive 2 is placed for transferring a rotation on the drill string 5. The rotary drive 2 is connected to the coupling 3 by its drive shaft 52. The coupling 3 is adapted such that it passes on said rotation from the rotary drive 2 to the drive shaft 51 , yet does not pass back a vibration of the vibratory drive 4 from the drive shaft 51 to the drive shaft 52. In this way the rotary drive 2 is not exposed to the vibration generated by the vibratory drive 4. The rotary drive 2, the coupling 3 and the vibratory drive 4 are preferably placed in a drive unit.

An exemplary embodiment of the coupling 3 according to the invention is shown in figure 2 in disassembled condition. Figure 3 here shows a view of the coupling device 3 in assembled condition, figure 4 shows a view in cross-section along the line A-A of figure 3, and figure 5 shows a view in cross-section along the line B-B of figure 3.

The coupling 3 comprises a first coupling member 10 for coupling to the rotary drive 2. At a side 1 1 of the coupling member 10, which side faces away from the coupling 3, said coupling member 10 is provided with connection means for rotation-fixedly connecting the coupling member 10 to the drive shaft 52 of the rotary drive 2. At the end 12 of the coupling member 10 placed within the coupling 3, substantially radially extending teeth 13 are placed.

The coupling 3 further comprises a second coupling member 20 for coupling to the vibratory drive 4. Said coupling member 20 is fixedly connected to a toothed ring 30 which forms a wearing part of the coupling 3. As shown in figure 5, the toothed ring 30 is provided with openings 36 for placing the teeth 13 of the first coupling member 10 therein. At the side of the toothed ring 30 that faces away from the coupling member 20, a Ud 40 of the coupling is disposed. Said lid 40 of the coupling comprises a central opening through which the first coupling member 10 extends for coupling with the rotary drive 2. The lid 40 of the coupling is fixedly connected to the second coupling member 20 by means of cylinder cap screws 33 and self-locking nuts 34. The toothed ring 30 is clamped between the lid 40 and the second coupling member 20.

The second coupling member 20, the lid 40 and the toothed ring 30 thus form a housing of the end 12 of the first coupling member 10, which end is placed within the coupling 3. The teeth 13 of the first coupling member 10 are placed within said housing and within the housing are able to move up and down, substantially along the centre line of the coupling 3.

When operative, the first end 1 1 of the first coupling member 10 will be rotation-fixedly connected to the rotary drive 2. The second coupling member 20 is then coupled to the vibratory drive 4.

When the vibratory drive is operative, the housing of the coupling 20, 30, 40 due to the vibratory drive 4, will perform a vibration that is substantially oriented along the centre line of the coupling. It is noted that the amplitude of the vibration has to be selected lower than the maximum stroke that the teeth 13 of the first coupling member 10 are able to make within the housing 20, 30, 40. The teeth 13 of the first coupling member 10 are able to slide up and down within the openings 36 of the toothed ring 30, as a result of which the rotary drive 2 substantially experiences no or strongly dampened vibration.

When the drill device is only driven by the vibratory drive 4, the teeth 13 can be placed within the openings 36 and preferably spaced apart between the teeth of the toothed ring 30, as a result of which friction between the surfaces of the teeth 1 3 and the teeth of the toothed ring can be minimised, so that wear in the coupling is strongly reduced or can be substantially prevented.

When the drill device is only driven by the rotary drive, the rotary drive will drive the first coupling member 10, as a result of which the teeth 13 will rotate within the openings 36 of the toothed ring until the teeth 13 with an abutment surface 16 abut an abutment surface 39 of the toothed ring 30. Subsequently the teeth 13 will drive the toothed ring 30 as a result of which the rotation of the first coupling member 10 will be passed on to the second coupling member 20. The entire coupling 3 will rotate because of the rotation, as a result of which the drive shaft 52 of the rotary drive 2 is effectively rotation-fixedly coupled to the drive shaft 51 of the drill device. In this way the rotary drive 2 is able to drive the drill string 5. it is noted here that when the rotation direction of the rotary drive 2 reverses, the coupling member 10 of the coupling 3 will first carry out a short free stroke prior to the teeth 13 once again abutting the teeth of the toothed ring 30 for once again driving the drill string 5 in opposite direction.

When the rotary drive 2 and the vibratory drive 4 are simultaneously active, the teeth 13 with their abutment surfaces 16 will abut the abutment surface 39 of the teeth of the toothed ring 30. Because of the vibration of the vibratory drive 4, the abutment surface 39 of the toothed ring will slide up and down along the abutment surface 16 of the teeth 13. As the vibration is generally carried out at a sonic frequency, the abutment surfaces 16, 39 are heavily loaded. Due to the friction between said surfaces a large quantity of heat can be generated. In order to keep said friction as low as possible, the housing 20, 30, 40 can be filled at the inside with a lubricant or lubricating oil. For that purpose a plug 35 is disposed in the toothed ring 30 along which plug the lubricant and/or the oil can be supplied within the housing. In order to substantially prevent leakage of the lubricant, a first cover plate 31 is disposed between the toothed ring 30 and the second coupling member 20, and a second cover plate 32 is disposed between the toothed ring 30 and the Hd 40. Also, around the first coupling member 10, a sealing ring 42 is placed in the lid 40. Because of this lubricant the friction between the abutment surfaces 16, 39 can be strongly reduced.

In the exemplary embodiment, as shown in cross-section in figure 4, the sealing ring 42 is placed in a wide chamber, as a result of which the sealing ring 42 in radial direction, substantially transverse to the centre line of the coupling 3, is able to move substantially freely. As a result radial disruptions that mainly originate from the drill string as a result of the drilling process, can be absorbed by the coupling 3. In axial direction the sealing ring 42 is confined between the cover plate 32 and the lid 40. At a side facing the cover plate 32 and at a side facing the first coupling member 10, the sealing ring 42 is provided with gaskins.

Nonetheless a large quantity of heat can be generated by the sonic vibration. Said heat can be partially discharged by means of cooling ribs 38 disposed at the outside of the toothed ring 30.

In order to ensure that the heat created does not weld the abutments surfaces 16, 39 together, the first coupling member 10 and the toothed ring 30 are made of different materials. In an exemplary embodiment the first coupling member 10 is made of steel. The toothed ring 30, serving as wearing part, is made of a softer metal, such as for instance yellow brass or bronze. Due to the softer material mainly the wearing part 30, particularly the teeth of the toothed ring, will wear. At a certain degree of wear, the wearing part 30 will have to be replaced.

In order to make the degree of wear of the teeth of the toothed ring 30 visible at the outside of the coupling 3, a wear-indicator 14 is attached to the first coupling member 10. In this exemplary embodiment the wear-indicator 14 comprises an element that is rotation-fixedly connected to the first coupling member 10, which element extends substantially radially with respect to the centre line of the coupling and which is provided with an indication member 15 extending in the direction of the wearing part 30. In the exemplary embodiment, as shown in figures 2, 5 and 6, the wearing part 30 on a part of its circumference is provided with a part 37 without cooling ribs 38. The indication member 15 is placed within this part 37. The part 37 without cooling ribs is larger than or equals the maximum stroke the teeth 13 of the first coupling member 10 are able to make within the openings 36 of the toothed ring, particularly including an increase of the openings due to wear. Within the part 37 a reference indication can be placed with a pre-determined threshold value indication for wear. Said threshold value indication can be formed by the ends of the cooling ribs 38. When the displacement of the wear-indicator, particularly its indication member 15, reaches or exceeds a pre-determined threshold value, the wearing part 30 has to be replaced.

In a further embodiment the wear-indicator can of course also be fixedly connected to the wearing part 30, wherein the reference indication with threshold-value indication is placed on the first coupling member 10.

The above description is included to illustrate the operation of preferred embodiments of the invention and not to limit the scope of the invention. Starting from the above explanation many variations that fall within the spirit and scope of the present invention will be evident to an expert.