GB2239276A - An hydraulic, horizontal thrust, rotary drilling machine - Google Patents

Abstract

An hydraulic, horizontal thrust, rotary drilling machine (10), particularly useful for installing a new pipe (111) in the ground, comprises a longitudinally extending frame (12) having two rotating screw-threaded shafts (38a, 38b), which are arranged on opposite sides of an hydraulic drill motor (48) which rotates a drill stem (115) and cutting head. The screw shafts (38a, 38b) extend through internally threaded holes in a travelling yoke (44) carrying the drill motor (48). A second hydraulic motor (not shown) is mounted on the frame (12) and drives the screw shafts (38a, 38b) for advancing and retracting the drill motor (48) together with the drill stem (115) and the cutting head (101). A pipe section (111) is rotatably mounted on the drill stem (115) so that the pipe can remain stationary as the cutting head is rotated by the drill stems. <IMAGE>

Description

HYDRAULIC, HORIZONTAL THRUST, ROTARY DRILLING MACHINE This invention relates to a hydraulic, horizontal thrust, rotary drilling machine, particularly such a machine for reaming a bore in the ground for a pipe and installing the pipe in the bore.

There is a known form of such a machine which requires accommodating in a trench, the depth below ground of the trench for accomodating the machine having to be substantially greater than the depth below ground of the bore to be reamed. Furthermore, this known machine has a yoke which is ram-driven. the yoke being connected to a drilling stem for doing the reaming. The yoke travel, and hence the forward travel of the reaming shaft, is limited to about half the length of the machine.

It is an object of the invention to provide a hydraulic, horizontal thrust, drilling machine which will require only a considerably shallower trench for accommodating the machine and will permit its yoke to travel forwardly almost the full length of the machine.

According to the invention, there is provided a hydraulic, horizontal thrust, drilling machine, adapted for reaming a bore for a pipe, in the ground, as claimed in each of the claims, to which reference is directed.

The invention will be described by way of example with reference to the drawings, wherein: Fig. 1 is a partly diagrammatic, side-elevational section on the centre-line of Fig. 2 of part of a machine embodying the invention Fig. 2 is a plan view of the machine part of Fig. 1; Fig. 3 is an end view of the machine of Figs. 1 and 2; Fig. 4 is a perspective view of a front part of the machine from above and behind, fitted with a first piece of a drilling stem and a first piece of a pipe to be installed in a bore to be reamed in the ground and showing a cutting head mandrel entering the bore; Fig. 5 is a perspective view of a front part of the machine, looking slightly forwardly and from left to right, fitted with the first drilling stem piece without the pipe piece;; Fig. 6 is a view of the front end of the machine, from slightly above, showing a starter bit for connection to the drilling stem; Fig. 7 shows a cutting head mandrel fitted with a nose cone; FIG. 8 is a sectional part view of a cutting head drive assembly and pipe-connection arrangement; FIG. 9 is a sectional part view showing the complete assembly for installation of the first piece of a new pipe, including means for supporting and forwardly driving the rear end of the first piece of pipe; FIG. 10 is a partly-sectioned part view of the connection of a hydraulic motor to the drilling stem and also showing the supported, forwardly drivable, rear end of the pipe: and FIG. 11 is a sectional part view of the joints between two pipe pieces and between two drill stem pieces.

Referring to the drawings, especially Figs. 1 to 6, the illustrated machine 10 is a hydraulic, horizontal thrust, drilling machine adapted for reaming a bore in the ground for a pipe. The machine 10 comprises a longitudinally extending frame 12, adapted to be located in a trench or cavity 14 in the ground, in general alignment, either with a pipe 16 which is to be replaced, or with a bore 18 which is to be reamed to receive a new pipe 111 (see below). The frame 12 comprises two longitudinally extending side members 20a, 20b. to the outsides of which are fixed laterally projecting bracing elements 22. The side members 20a, 20b are interconnected by a series of transoms 24 at the bottom of the frame 12.At the front end 26 of the frame 12 are two end plates 28a, 28b, extending towards each other from the respective side members 20a, 20b, and defining a substantial gap 30 therebetween through which pieces of a drilling stem 115, pipe 111 and other elements can extend. A rear end plate 34 extends across the rear end 36 of the frame 12, between the two side members 20a, 20b.

Two screw-threaded shafts 38a, 38b extend along the frame 12 from one end 26 to the other end 36, being journalled in two bearings 40a, 40b at the front end 26 and in two bearings 42a, 42b at the rear end 36. The two front bearings 40a, 40b are fixed respectively to the two end plates 28a, 28b, whilst the two rear bearings 42a, 42b are fixed to the rear end plate 34.

A longitudinally movable yoke 44 is carried by the two screw-threaded shafts 38a, 38b, which extend through two internally threaded bores 46a, 46b in the yoke 44.

The yoke 44 carries a first rotary hydraulic motor 48 which is co-axial with the drilling stem 115. The motor 48 is provided for rotatably driving the drilling stem 115. The motor 48 does not itself provide any forward or reverse feed for the drilling stem 115.

A second rotary hydraulic motor 54 is mounted on the rear end plate 34 and rotatably drives the shafts 38a, 38b through a chain drive 56 comprising a chain 58 and sprockets 60a, 60b on the shafts 38a, 38b respectively and a sprocket 62 on the output shaft of the motor 54.

Operation of the motor 54 causes rotation of the two shafts 38a, 38b together and hence forward or reverse feed of the yoke 44, according to the direction of rotation of the motor 54. The forward/reverse feed of the yoke 44 produces corresponding forward/reverse feed of the drilling stem 115, while the latter is rotatably driven by the other motor 48.

It will be seen that the two screw-threaded shafts 38a, 38b are located one on each side of the drilling stem 115 and extend parallel to it. The machine 10 is shallow and wide and does not require a deep trench to accommodate it. Also, there is only little bending moment between each screw-threaded shaft 38a, 38b on the one hand and the drilling stem 115 on the other hand.

The distance that the yoke 44 travels forwards, or backwards for pulling, is substantially the full length of the machine 10.

Fig. 7 shows a cutting head mandrel 101, fitted with a nose cone 101A.

Before describing what is shown in Figs. 8 to 11, it should be explained that initially only one piece of the pipe 111 - the first or front piece 111/1 - and only one piece of the drill stem 115 - the first or front piece 115/1 - is fitted to the machine 10, with the cutting head mandrel 101 at the very front. When the first pipe piece 111/1 and first drill stem piece 115/1 have been driven into the bore in the ground (as described in detail later) they are disconnected from the machine 10. Then a second pipe piece 111/2 and second drill stem piece 115/2 are inserted between the machine 10 and the first pipe and drill stem pieces 111/1 and 115/1 and are driven into the bore, then third pipe and drill stem pieces (not shown) are inserted and driven into the bore, and so on.The cutting head mandrel 101, of course, remains at the front of the first pipe and drill stem pieces 111/1 and 115/1 until installation is complete. Figs. 8 to 10 show only the first pipe and drill stem pieces 111/1 and 115/1, whilst Fig. 11 merely shows the joints between them and the second pipe and drill stem pieces 111/2 and 115/2.

Referring to Figs. 8 to 11, and especially Fig. 8, the cutting head mandrel 101 is connected as shown to a solid hexagonal drive shaft 107. More particularly, a hexagonal drive coupling unit 102 mates with the shaft 107, abutting a solid thrust collar 108 on the shaft 107. At the rear end of collar 108 is a standard frusto-conical, internally screw-threaded, female" drill stem joint 109. Hexagonal drive unit-fixing bolts 102A fix the mandrel 101 to the coupling unit 102 as shown. A pipe collar 104 is mounted on the coupling unit 102 via a main bearing 103. A pipe collar relief bearing 105 acts between the collar 104 and a pipe collar locking bush 106 which is secured to the coupling 102 by locking bush fixing bolts 106A.

A retaining plate 110 is secured to the front end of the shaft 107 by a plate-fixing bolt 110A. On withdrawal, the plate 110 engages the coupling 102 so that the mandrel 101 can be pulled back by the shaft 107.

The front end of the first, or front. piece 111/1 of a new pipe 111 is secured temporarily to the collar 104 by pipe-fixing bolts lllA, accessible through a hole 112 in the shell of the mandrel 101.

Because of the bearings 103 and 105, the drive shaft 107 and mandrel 101 can be rotatably driven without rotating the pipe 111.

Fig. 9 shows the rear end of the front piece 111/1 of pipe 111 as well as the front end, with a break between them. The rear end is shown seated inside a pipe cap 119, secured by pipe cap-fixing bolts ll9A to a pipe cap base section 118, mounted via a pipe cap bearing 117 and bearing support bush 116 to the drilling stem 115. The front drilling stem piece 115/1 has a standard frusto-conical, externally screw-threaded "male" drill stem joint 113 which engages the female joint 109 of the collar 108 on shaft 107. The rear end of the front drill stem piece 115/1 has a standard female joint 109 identical to that on the drive shaft 107. The pipe cap 119 is retained on the rear end of the pipe piece 111/1 by a retaining plate 120, which itself is held in position on the drilling stem 115/1 by a locking clamp 121.It will be seen that spanner flats 114 are provided on a rear end portion of the drilling stem piece 115/1, for holding it against rotation when unscrewing the joints 109 and 113. Similar spanner flats are provided on rear end portions of all of the drill stem pieces.

Referring especially now to Fig. 10, the first motor 48 (Figs. 4 to 6) has a splined motor shaft 129 protruding from a front face 130 of the motor 48 and drivingly engaging a forward-and-reverse thrust bearing bush 126 which is bolted to a starter bit flange 123 by flange-fixing bolts 123A. The flange 123 is welded to a starter bit 122, which also has spanner flats 114. The front end of the starter bit 122 has a standard male joint 113, screwed into a standard female joint 109 at the rear end of the drilling stem 115 as shown.

The bush 126 is mounted within a bearings-housing 128 via a reverse thrust bearing 124 and a forward thrust bearing 125. The housing 128 is bolted to the front face 130 of motor 48 (Figs. 4 to 6) by housing-fixing bolts 128A.

Fig. 11 shows how, in known manner, an externally annularly ribbed, frusto-conical nose, or male joint, 150 at the front end of the second pipe piece 111/2 mates with a correspondingly formed recess, or female joint, 152 at the rear end of the first pipe piece 111/1, and also how the female joint 109 at the rear of first drill stem piece 115/1 mates with the male joint 113 at the front of the second drill stem piece 115/2.

Whereas the first pipe piece 111/1 and first drill stem piece 115/1 are located relative to each other by the cutting head mandrel 101 at their front ends, the front end of each subsequent drill stem piece 115/2 etc.

locates the front end of the corresponding pipe piece 111/2 etc. by virtue of a respective roller bearing cage 131, clamped to the drill stem piece 115/2 etc. as shown, with its rollers engaging the inside surface of the corresponding pipe piece 111/2 etc.

PiDe Installation Procedure (Parts 1 & 2) Part 1 The first part of this procedure involves the front pipe piece 111/1, which has to be short enough for the cutting head 101 and pipe piece 111/1 together to be accommodated within the machine area.

This piece of pipe 111/1 should be cut to length, prepared and fitted to the pipe retaining collar 104, within the rear section of the cutting head 101, together with the first drill stem piece 115/1, before arrival on site.

This completed assembly, that is, the cutting head 101 and the first pipe and drill stem pieces 111/1 and 115/1 should then be lowered into the machine area and the nozzle 101A inserted into the existing pipe 16 (Fig. 4) to be replaced, and the pipe and drill stem pieces 111/1, 115/1 are suspended horizontally in line with the centre of the existing pipe 16. The assembly of the rear female pipe collar 104 and cap 119 should at this stage be placed (only resting) on the starter drill bit 122.

The screws 38a, 38b should now be rotated by motor 54 and the drill motor 48 brought forward, allowing the starter drill bit 122 to couple with the drill stem piece 115/1. At this stage the drill motor 48 should be turned in conjunction with the screws 38a, 38b to complete the "pin and box" drill stem joint.

The rear female pipe collar 104 and cap 119 should then be brought forward and locked into place, completing the pipe installation for readiness to be installed.

Motors 48, 54 are then started.

It is desirable, during this first part of the pipe installation, to limit the forward speed of the push (that is, limit the speed of motor 54) while rotating the cutting head 101 at the required speed to get a clean, compact, entry hole.

Part 2 The second part of the procedure is repeated until the installation has been completed.

This part involves breaking the joint between the starter bit 115 and the incumbent drill stem piece 115/1 and the eventual re-loading and installation.

1) Initially both motors 48 and 54 are running as at the end of Part 1. When the spanner flats 114 on the drill stem piece 115/1 reach a predetermined position, the screw motor 54 should be stopped and the drill motor 48 slowed down and stopped with the flats 114 vertical.

2) A conventional "break out system" (not shown) should then be lowered to engage the flats 114 on the drill stem piece 115/1.

3) The drill motor 54 is then re-started in reverse, to crack the joint, (2-3 Turns) and stopped.

4) When this has been done, the "break out system" is raised from the drill stem, and the screw motor 54 is re-started in reverse to pull the pipe and drill stem pieces 111/1 and 115/1 back 25 mm (1") further than the length of the pipe joint, and motor 54 is then stopped.

5) The drill motor 48 is re-started again to complete the release of the remainder of the joint threads and then stopped.

6) The screw motor 54 is re-started again in reverse and the drill motor 48 is taken back by screws 38a, 38b to the rear limit position on the machine. The pipe end cap 119 and collar 104 are removed and rested again on the starter bit 122.

7) The next pieces 111/2, 115/2 of pipe and drill stem are then lowered to the level of the first pieces 111/1, 115/1.

8) The new drill stem piece 115/2 is manually connected to the existing drill stem piece 115/1 and then the drill motor 48 is brought forward, by running screw motor 54, to engage the starter bit 122 into the rear joint 109 of the new drill stem piece 115/2, and the joint is completed by turning the drill stem motor 48. Then the motors 48, 54 are stopped.

9) The new pipe piece 111/2 should then be put into place, by engaging the front end male joint 150 with the existing pipe female end 152.

The rear pipe cap 119 and collar 104 are then brought forward and locked into position.

10) The screw motor 54 should then be re-started on full speed, which results in the rear pipe cap 119 providing the thrust to close the pipe joint 150, 152.

11) The rear pipe cap 119 should then be slackened from the drill stem 115 and the screw motor 54 re-started to re-adjust the drill stems pieces 115/1, 115/2 to a thrust position in the cutting head 101.

12) Then the pipe end cap 119 is relocked and motors 48, 54 re-started, as at the end of Part 1 and beginning of Part 2.

Part 2 is repeated with subsequent pipe and drill stem pieces (not shown) until the ultimate manhole is reached.

Claims (4)

Claims:-

1. An hydraulic, horizontal thrust, rotary drilling machine, comprising a longitudinally extending frame, adapted to be located in a cavity in the ground, in substantial alignment with the pipe or hole to be reamed, a first rotary hydraulic motor adapted to be drivingly connected to one end of a reaming shaft, drill stem or the like, an axially movable mounting for said first motor, two screw-threaded shafts rotatably mounted in the frame and extending one on either side of and parallel to the axis of the reaming shaft, drill stem or the like, said two screw-threaded shafts extending through, and being screw-threadedly engaged with, the mounting for said first motor, and a second rotary hydraulic motor drivingly connected to said two screw-threaded shafts, said first motor being arranged between said two screw-threaded shafts, whereby in use the first hydraulic motor rotates the reaming shaft, drill stem or the like, while the second motor drives the reaming shaft, drill stem or the like along the pipe or the hole.

2. A machine as claimed in claim 1, wherein the reaming shaft, drill stem or the like extends forwardly of the first motor.

3. A machine as claimed in claim 1 or 2, wherein the two screw-threaded shafts each extend the full length of the frame.

4.A machine as claimed in claim 1, 2 or 3, wherein the second motor drives the two screw-threaded shafts through a chain and sprockets.