WO1988002435A1

WO1988002435A1 - Boring apparatus

Info

Publication number: WO1988002435A1
Application number: PCT/AU1987/000328
Authority: WO
Inventors: Aurelio Pezzimenti
Original assignee: G. Pezzimenti & Sons Pty. Ltd.
Priority date: 1986-09-24
Filing date: 1987-09-23
Publication date: 1988-04-07
Also published as: EP0324778A4; JPH02500041A; CN87106795A; EP0324778A1

Abstract

A boring apparatus (2) having a boring head (13) for boring a bore (3) of a predetermined axis in which the position of the boring head (13) is controlled by a guidance system comprising a first part (4) of the boring apparatus (2) is fixed at a first location in a shaft (7) at the beginning of the bore (3) and is provided with a transmitter (17) for transmitting a controlling signal along the predetermined axis of the bore (3) to a sensor (102) located on a second part (12) of the boring apparatus at a remote location from the first part (6) towards the face of the bore (3), said second part being provided with the boring head (13) which is movable inside the bore (3) with respect to the second part in use wherein said second movable part (12) is provided with a motor means (52, 82) connected to the boring head (13) for adjusting the position of the boring head (13) such that when the boring head (13) deviates from the predetermined axis of the bore (3) by a preselected amount said controlling signal received by the sensor (102) automatically activates said motor means (52, 82) to reposition the boring head (13) in closer alignment on the predetermined axis thereby forming a bore (3) in substantially close conformity with the predetermined axis.

Description

BORING APPARATUS The present invention relates to a control system incorporating a guidance system in general, and in particular, to a method and apparatus for drilling and/or boring over which greater control of the cutting head may be exercised. One particular aspect of the present invention relates to a drilling or boring apparatus having an improved guidance system for accurately controlling the position of a drilling or boring head which is located at a location remote from the driving motor means of such apparatus. Even more particularly, the present invention relates to an apparatus having a laser controlled drilling head for boring substantially constant slope or straight bores underground. _ _

The apparatus of the present invention finds particular application in drilling or boring relatively small bores of the order of from 200 to 2000 mm, or larger_^ However, it is to be noted that the present invention may be equally applicable to drilling or boring much larger holes or bores if required or desired.

Although the present invention will be described with particular reference to an apparatus for drilling more or less straight bores under the earth's surface by means of a drilling or boring head which has its position accurately controlled by means of a laser arrangement existing between the drilling or boring head and the driving means, it is to be noted that the present invention is not so limited and can extend in scope to include other arrangements of the apparatus for achieving similar results or to similar apparatus for use in other applications. Other such other applications usually associated with the apparatus of the present invention include pipe jacking or sleeve boring or the like which includes pushing pipes into the bore simultaneously with boring the bore.

The present invention finds particular application in boring underground drainage conduits, into which underground drainage pipes are usually inserted such as by means of pipe jacking or similar, such as for example to conduct sewerage from areas of dense populations to remote locations where the sewerage may be treated. Such drainage bores are required to be of a more or less constant slope since the drainage system for sewerage applications depends more or less upon gravity feed to transport waste material to the treatment stations. Accordingly, the drainage bores are required to be of a constant slope since interruptions to the constant slope such as flat spots or areas of lesser slope interrupt the smooth flow of the waste material and can cause blocking of the drainage or sewerage systems. At present it is usual to have bores with slopes of no less than one in eighty. In order to ensure that the correct slope is being maintained shafts extending between the bore and ground level are located at regularly spaced apart locations over the entire length of the bore. The typical spacing of shafts is about 10 to 15 metres apart over the entire length of the bore. The drilling or boring machine is re-aligned a each shaft location to ensure that the constant slope and direction of the bore is being maintained. The need for providing many shafts at more or less regularly spaced apart locations over the entire length of the bore is extremely costly and time consuming. Accordingly, it is an aim of the present invention to provide a method and apparatus for drilling substantially straight bores underground having a substantially constant slope with a greater accuracy than hitherto before has been attainable with existing boring machines. This aim is essentially achieved by maintaining greater control over the boring machine the position of which is being continually monitored and its position constantly adjusted to bore precisely along a preselected trajectory or pathway. One advantage of the present invention is that the distance between adjacent shafts can be increased, such as for example to a spacing or about 100 m or even greater, since the boring machine is being more accurately controlled. A further advantage is that the slope of the bore may be reduced because the bore has a more constant slope which means that flat spots are eliminated or reduced. According to the present invention there is provided an earth working machine comprising, a fixed main body portion having a driving means and a movable earth working portion having an earth working element movable with respect to the earth working portion, said earth working element connectable to and being capable of being driven by the driving means in use, a signal transmitter fixedly connected to the main body portion and a receiver fixedly connected to the movable earth working element at a preselected location so as to receive a signal from the transmitter, said earth working portion being provided with a control means for controlling the position of the earth working element relative to the earth working portion in accordance with the signal received by the receiver such that the earth working element is maintained within certain predetermined limits from its desired preselected position in use.

According to the present inventTxon there is provided a boring apparatus having boring means for boring a bore of a predetermined axis in which the position of the boring means is controlled by a guidance system comprising a first part of the boring apparatus fixed at a first location in the bore provided with a transmitter means for transmitting a controlling signal along the predetermined axis of the bore to a receiver means located on a second part of the boring apparatus at a remote location from the first part, said second part being provided with said boring means and being movable along the axis of the bore in use wherein said second part is provided with a motor means connected to said boring ^"means for adjusting the position of the boring means such that when said boring means deviates from the predetermined axis of the bore by a preselected amount said controlling signal received by said receiving means automatically activates said motor means to reposition said boring means in closer alignment with the predetermined axis thereby forming a bore in substantially close conformity with the predetermined axis. According to another aspect of the present invention there is provided a method of boring an underground conduit of a preselected configuration using a boring apparatus of the ^•type having a fixed body portion having driving means for driving a movable boring head provided on a boring portion capable of being advanced in a forward direction along the longitudinal axis of the bore wherein the position of the boring head with respect to the boring portion is accurately controlled by a control means provided on the boring portion connected to the boring head comprising transmitting a control signal from a transmitter means fixedly located on the fixed body portion to a control signal receiving means fixedly connected on the boring portion whereupon the control signal is used to activate the control means to accurately maintain the boring head within certain predetermined limits from the desired preselected position for boring the conduit of the preselected conduit in use.

Typically, the signal transmitter means and the signal receiver means is a laser arrangement in which the transmitter converts electrical signals into a laser beam and the signal receiver means has sensor means for converting the laser into an electrical signal. Typically,_ there is a straight line of sight pathway between the transmitter and the sensor. Typically, the laser beam produced by the transmitter^" is a pulsed laser beam. Typically, the sensor has a plurality of targets comprising a single central target and several spaced apart targets surrounding the central target.

Typically, the control member or means is an electrically operated linear actuator of the type having an integral electric motor driving an extendable/retractable ram or is an electric motor having a rotary output shaft or is a hydraulic motor/pump arrangement.

Typically, there is a first electric motor or linear actuator or hydraulic motor/pump for controlling the movement of the boring means in an upwards and downwards direction which is substantially perpendicular to the lengthwise extending axis of the bore and a second electric motor or linear actuator for controlling the sideways movement which is substantially perpendicularly left or right of the longitudinal axis of the bore.

Typically, the second movable part of the boring apparatus is provided with an exhaust conduit which is connected by one or more exhaust ducts insertabl.e between the fixed part and the movable part of the boring apparatus for connection to a vacuum system above ground at a remote location for removing waste material produced by the cutting head in the bore to above the ground for subsequent disposal. Typically, the waste material is dry and of a particle size range that may be transported by the vacuum system.

Alternatively, the dry waste material may be mixed with water to form a slurry which is pumped or otherwise removed by the vacuum system. Typically, the vacuum system is contained, apart from the exhaust conduits on a mobile vehicle, such as for example a truck.

Typically, the movable portion is provided with a main drive shaft coupled to the driving motor of the fixed part. Typically, the forward end of the drive shaft is moved by the electric motors or linear actuators or hydraulic motor/pump and more or less pivots about its rear end in use. Typically, the drive shaft is mounted on a subassembly and is connected to the string of drive rods by a universal joint- so that when the subassembly moves the drive shaft moves accordingly so that it remains parallel to the subassembly.

Typically, the housing or casing is articulated at some point over its length to allow the forward portion to bend with respect to the rearward portion.

The present invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 is an overall view of one form of the apparatus of the present invention in use located within a shaft for boring a horizontally sloping bore;

Figure 2 is a perspective view of one form of the drilling portion of one form of the apparatus in accordance with the present invention; Figure 3 is an exploded view showing the component parts of the apparatus of Figure 2.

Figure 4 is a perspective view of another form of the drilling portion of one form of the apparatus of the present invention with the top cover removed; Figure 5 is a plan view of the apparatus of Figure

4;

Figure 6 is a right hand side elevation view of the embodiment of Figure 4;

Figure 7 is a left hand side elevation view of the embodiment of Figure 4;

Figure 8 is a transverse cross-section taken along the line 8 to 8 of Figure 5; Figure 9 is a schematic view of one form.of the vacuum collection system for waste removal used in conjunction with the present invention.

Figure 10 is a top plan view of a further embodiment of the boring portion of the present invention in isolation not connected to the main housing or exhaust duct.

Figure 11 is a cross-section view through the line 11 to 11 of Figure 10.

Figure 12 is a top plan view of a further embodiment of the boring portion of the present invention.

Figure 13 is a cross-section view through the line 13 to 13 of Figure 12.

It is to be noted in the present specification that the use of relative terms such as forward, backward, up, down, left, right and the like refer to the normal in use configuration of the apparatus, looking in the direction of boring in the bore so that the words forward and backward refer to the direction of the longitudinal axis of the bore with forward being in the direction from the shaft to the face of the bore and left and right refer to the respective sides of the apparatus facing forward in the bore.

In Figure 1 there is shown a drilling or boring apparatus, generally denoted as 2 for drilling or boring a more or less horizontally sloping underground bore 3 or conduit. Apparatus 2 which in part is fixedly located at the bottom of a shaft 7 comprises a main support framework portion 4 and a pair of elongate running rails 5a, 5b arranged so that the running rails 5a, 5b extend in the direction in which it is desired to drill bore 3. A motor-containing sub-assembly 6 is located on rails 5a, 5b to travel backwards and towards along the rails during operation of the boring apparatus 2 while drilling bore 3 between a fully withdrawn position as shown in Figure 1 and a fully advanced position in which the forward end of sub-assembly 6 is adjacent the forward end of rails 5a, 5b. A hydraulic ram 18 is provided on either side of sub-assembly 6 to extend and retract the sub-assembly 6 in use. The extent of extension of the rams 18 limit the amount 88/02435

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of travel of sub-assembly 6 in the forward direction as also does the presence of stops 9 towards the ends of the rails 5a,

5b.

A hydraulically driven motor 10, or other suitably powered motor, is provided on sub-assembly 6 for driving rotatable driving shaft 11, made up of a string of individual drive shafts, extending forwardly from the motor 10 to a boring portion 12 of the boring apparatus 2. Boring portion 12 comprises boring head 13 or other suitable cutters or the like for actually cutting the bore- 3 at the extreme forward end of the boring portion 12 and is connected to driving shaft 11 to rotate in accordance with rotation of motor 10. The details of boring portion 12 will be described in more detail later. Exhaust duct 14 which comprises a first exhaust duct 20 located longitudinally along the lower part of boring portion 12 and a plurality of insertable ducts extends between the boring portion 12 and the sub-assembly 4 and is connected to a vacuum system,- Figure 9, located on the ground surface away from shaft 7, by means of a flexible exhaust conduit 16 extending from sub-assembly 6 to the vacuum system for removing waste material from the bore 3 during operation of the apparatus of the present invention. A laser transmitter 17 for producing and transmitting pulsed signals in the form of a laser beam is very accurately positioned on to framework 4 at its rear to transmit the laser beam to a sensor 102 mounted on the drilling portion 12 to accurately guide the drilling portion 12 when boring.

Briefly, in operation boring portion 12 is connected directly to sub-assembly 6 with the output shaft of the motor directly coupled to the drive shaft of the boring portion and motor 10 rotated to drive boring head 13 in rotation thereby beginning to cut bore 3. As cutting head 13 rotates sub-assembly 6 is moved on rails 5a, 5b in the direction towards bore 3 by operation of rams 18 thereby forcing boring portion 12 further into the ground to begin to form bore 3 by allowing cutting head 13 to further cut into the ground to form bore 3. When sub-assembly 6 reaches the extent of travel _ ____ 9 _

defined by stop 9, shaft 11 and exhaust conduit 14.are disconnected from motor 10 and sub-assembly 6 respectively and sub-assembly 6 moved backwards to its fully withdrawn position by fully retracting rams 18. An additional driving rod 11a and exhaust duct 14a are connected between the sub-assembly 6 and boring portion 12 and sub-assembly 6 moved forward on rails 5a, 5b again with the motor rotating thereby forcing boring portion 12 further into the ground to form bore 3 thereby advancing further the length of bore 3. When sub-assembly 6 has reached the full extent of its forward travel as limited by the extent of hydraulic ram 18 and stops 9, the additional shaft 11a and exhaust conduit 14b are disconnected from sub-assembly 6, sub-assembly 6 is fully withdrawn and a further shaft lib and exhaust conduit 14b inserted and the boring operation commenced. This process is repeated until the extent of bore 3 is fully bored whereupon the reverse occurs to clear the bore 3 of boring portion 12. Turning now to boring portion 12 of which one form is shown in more detail in Figures 2 and 3 it can be seen that drilling portion 12 comprises a number of interrelated components which effect guidance of boring head 13. Exhaust duct 20 which extends longitudinally along the entire length of the drilling portion 12 provides the main frame member of the drilling portion 12 and is used to interconnect the components mounted towards the rear of the boring portion 12 and at the front. Rear support sub-assembly, generally denoted as 22, is fixedly connected to the rear end of exhaust duct 20. The rear support assembly 22 comprises a generally semi-circular support bracket 24 fixedly connected to the undersurface of exhaust duct 20. A spring loaded fastener 23 is provided at either end of bracket 24 to securely retain top cover 26 in place during operation yet allow top cover 26 to be released easily. Top cover 26 is pivotally mounted to boring portion 12 by means of a pair of brackets 25 fixedly connected to plates 27 extending outwardly from either side of exhaust duct 20 and a pair of brackets 28 rigidly connected to „_,_„.,- O 88/02435

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the inner surface of cover 26 and carrying extension pieces 29. Brackets 29 pivot with respect to brackets 25 to form hinges for the movement of.top cover 26.

A front support subassembly 32 is fixedly connected 5 to the front end of exhaust duct 20. Front sub-assembly 32 comprises semi-circular support bracket 34 fixedly connected to the underside of exhaust duct 20 at its extreme front end and a plate 33 fixedly connected to the upper surface _of exhaust duct 20 extending from bracket 34 inboard along duct

10 20. On one side of plate 33 which is on the left hand side in use is located a bifurcate support or yoke 35 comprising two substantially upright opposed arms 35a, 35b, arranged generally parallel to each other and extending upwardly perpendicularly to plate 33. The opposed pair of arms 35a,

15 35b are each provided with an aperture 36 which are aligned with each other. Bell crank 40 is located intermediate the two arms 35a, 35b and is connected thereto by pin 42 which is received through the aligned apertures 36 and aperture 44 of bell crank 40 located intermediate the two ends so as to form

20 the pivot point for bell crank 40. Pin 42 is securely retained in place by being integrally formed with web 46 which in turn has one end securely fastened to the arm 35a by bolt 48. One end of bell crank 40 is bifurcate having a pair of opposed arms 50a, 50b to form a yoke. The distal ends of

25 opposed arms 50a, 50b are each provided with an aperture which are aligned with each other. Fastener 54 is received through the aligned apertures of bifurcate arms 50a, 50b to pivotally connect bell crank 40 to a ring provided at the distal end of extendable/retractable ram 56 of linear actuator 52. Linear

30 actuator 52 comprises a motor housing portion 52a for housing an electrically driven motor and the extendable/retractable ram portion 56 arranged in one unit such that operation of the electric motor causes ram 56 to extend or retract accordingly. The other end of bell crank 40 is provided on its inboard side

35 with a recess 58 for receiving the distal end of trunnion 60 of bearing block 62. Bearing block 62 is free to slide longitudinally along trunnion 60 from one end to the other end _ 11 _

and also to pivotally rotate about trunnion 60. Movement of bearing block relative to trunnion 60 will be described in more detail later.

Drive shaft 70 is arranged to lengthwise extend along the longitudinal axis of the drilling portion 12 aligned above and parallel to exhaust duct 20 between the rear support assembly 22 and the front support assembly 32. Bearing block 62 is provided with bearing 64 located internally within the block. Shaft 70 is journalied inside bearing 64 and is thus permitted to rotate with respect to bearing block 62. Rear support assembly 22 is provided with a locating bracket 30 provided with a suitable bearing which locates shaft 70 while allowing it to rotate. Even though bracket 30 allows shaft 70 to rotate the actual position of the shaft is fixed with respect to the drilling portion since bracket 30 is rigid.

Thus, in effect shaft 70 pivots about a point along its length corresponding to where it is journalied by bracket 30. Front support assembly 32 permits movement of the forward end of rotary shaft 70 with respect to the remainder of the drilling portion by having the bearing block 62 which is movable in two directions. One direction is up and down with respect to exhaust duct 20 and accordingly can alter the position of the drilling portion 12 up and down whereas the other direction is from side to side with respect to exhaust duct 20 which accordingly allows the position of drilling portion 12 to move left or right. Movement of the forward end of shaft 70 permits adjustment of the actual position of cutting head- 13 which is fixedly attached to the forward end of drive shaft 70 thereby maintaining the position of head 13 within the predetermined limits so as to form the constant preselected slope of bore 3.

Returning now to front sub-assembly 32, it can be seen that upright support bracket 38 is located on the left side of plate 33 to extend upwardly therefrom to ultimately provide support for the other side of bearing block 62.

Support bracket 38 extends perpendicularly upwards from plate 33 and is provided with an aperture 39 towards its top edge. 8/02435

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Connecting yoke 72 having one end bifurcated with a pair of opposed arms 73a, 73b each having an aperture near their respective ends is received over support bracket 39 with arms 73a, 73b on either side^~of aperture 39 so that their apertures are aligned with aperture 39. A pin 74 is received through aperture 39 and the aligned apertures of arms 73a, 73b to pivotally connect connecting yoke 72 to support bracket 38. The other end of connecting yoke 72 is provided on its inboard side with a recess 75 for receiving the opposite trunnion 76 of_ bearing block 62 so as 'to support bearing block 62 in use. Thus, in use, operation of linear actuator 52 causes corresponding movement of drive shaft 70 and attached boring head 13 together with bearing block 62 in an up and downwards direction with respect to the exhaust duct 20 which will be described in more detail later.

Again, returning to the front support assembly 32 the means for adjusting the side to side movement of boring head 13 will now be described. Extension piece 80 is fixedly connected to the rear of plate 33 towards its left hand outboard side to project rearwardly of plate 33 substantially parallel to exhaust duct 20 for attaching a second linear actuator 82 thereto by means of bolt 81 passing through aligned apertures provided on actuator 82 and on extension piece 80. Actuator 82 which comprises a motor housing portion 82a integrally arranged with an extendable/retractable ram 84 extending from one end thereof is arranged to lie substantially parallel to exhaust duct 20 with ram 84 aligned so as when it extends it moves towards front sub-assembly 32 and when it retracts it moves towards rear sub-assembly 22. Ram 84 at its distal end is connected to the bifurcated end 86 of bell crank 88 by means of the opposed pair of arms 86a, 86b forming the bifurcated end being located on either side of the end of ram 84. Bell crank 88 is pivotally connected to plate 33 by means of a fastener 90 extending perpendicularly upwardly from plate 33 and passing through aperture 92 of bell crank 88. Aperture 92 is located towards the end of the bell crank away from the end to which ram 84 is connected. The other end 94 of bell crank 88 is connected to one end of adjustable tie rod 96. The other end of adjustable tie rod 96 is connected to central bearing block 62. Thus, operation of linear actuator 82 produces corresponding movement of central bearing block 62 in a side to side movement along the axial direction of trunnions 60,76 which will be described in more detail later.

An adjustable collar or circular clamp 100 is provided at the top of floating bearing block 62^~for securely holding sensor 102 fixedly to block 62 and thus accurately positioning the sensor with respect to bearing block 62. Sensor 102 is provided with five discrete photo-electric cells 103 to 107 which function as receivers for the pulsed signal sent by laser transmitter 17 connected to framework 4. Sensor 102 is in electrical contact with relay motor control box 110 which in turn is in electrical contact with both linear actuators 52, 82. Each of the photo-electric cells controls movement of the linear actuators in different directions as well as providing for a warning system in the event of malfunction of the boring apparatus. Shield 108 is connected to plate 33 by means of elongate bracket 109 to provide a mask for the laser beam to further provide a fail-safe device in the event of malfunction of the boring apparatus.

In operation, drilling apparatus 2 with its sub-assembly 6 in the fully withdrawn position is located at the bottom of shaft 7 with the boring head 13 in contact with the shaft wall where it is proposed to drill to form bore 3. Laser transmitter 17 is accurately positioned upon a framework 4 so as to direct the pulsed beam to drilling portion 12 in accordance with the desired direction and inclination of the bore being formed. The laser transmitter 17 is provided with an adjustable setting which may be preset in accordance with the desired slope of the bore. Hydraulic motor 10 is activated to rotate shaft 11 and correspondingly cutting head 13 to commence boring. As described previously sub-assembly 6 is moved towards bore 3 by ram 18 thereby forcing boring portion 12 and cutting head 13 further into bore 3 to further _ ^ _

extend bore 3. When sub-assembly 6 has reached thς limit of its travel it is disconnected from shaft 11 and retracted to its original position at the bottom of shaft 7 so that additional shafts 11 and conduits 14 may be inserted between boring portion 12 and sub-assembly 6 so that as subassembly 6 is moved by ram 18 boring portion 12 is forced further into bore 3 so as to further extend the length of bore 3.

During boring laser transmitter 17 operates at about 10Hz and accordingly^"transmits about 10 pulses per second towards sensor 102. Central photo-electric cell 103 is the normal target for the pulsed beam from transmitter 17 and when the drilling portion 12 is accurately aligned to produce the bore 3 of desired direction and inclination the pulses impinge on photo-electric cell 103. Due to various reasons drilling portion 12 sometimes becomes disaligned from the exact slope of the bore and begins to drill off centre away from the desired direction and inclination. As this occurs pulses from transmitter 17 impinge upon one of the peripheral photo-electric cells 104 to 107 thereby transmitting a signal to relay box 110 to adjust the position of boring head 13. When the pulsed beam from transmitter 17 impinges upon photo-electric cell 104 which is located above the central photo-electric cell 103 this is indicative that the boring portion 12 is below the incline of transmission of the pulsed beam and accordingly is boring a slope of greater magnitude than is desired. When the transmitter beam impinges on photo-electric cell 104 an electric signal is produced in sensor 102 which is relayed to actuator 52 via relay box 110 to cause actuator 52 to slightly retract ram 56. As ram 56 retracts bell crank 40 raises slightly the position of bearing block 62 and shaft 70 together with cutting head 13 with respect to exhaust conduit 20 thereby readjusting the position of cutting head 13 to the correct alignment and thus maintaining boring at the correct slope and allowing the pulsed beam to impinge on central photo-electric cell 103 again. _ ^ _

If the transmitted beam impinges upon photo-electric cell 105 which is located immediately below central photo-electric cell 103 this indicates that the boring portion 12 is forming the bore of lesser slope than is desired. When the transmitted beam impinges on photo-electric cell 105 an electrical signal is transmitted to relay box 110 and to actuator 52 to extend ram 56 which -in turn causes the bearing block 62 to be slightly lowered by means of the bell crank 44 so that shaft 70 journalied in bearing block 62 is slightly lowered and accordingly cutting head 13 is slightly lowered with respect to the exhaust conduit 20 thereby readjusting the position of the cutting head to maintain a correctly aligned bore. Actuator 52 is operated until the transmitted pulsed beam impinges on photo-electric cell 103 again. Similarly, photo-electric cell 106 located to the right side of central photo-electric cell 103 is used to control movement of actuator 82 to retract ram 84 which in turn moves bell crank 88 and tie rod 96 to cause bearing block 62 to slide on axle 60 towards the left hand side thus bringing shaft 70 and cutting head 13 into alignment with the correct direction and inclination of the bore. When the transmitted beam impinges upon photo-electric cell 107 which is located to the left of central photo-electric cell 103 a signal is transmitted to actuator 82 to extend ram 84 which in turn causes bearing block 62 to slide towards the right hand side of the boring portion to realign the shaft and cutting head to the correct slope of bore.

In addition, sensor 102 is designed such that if the transmitted beam from transmitter 17 is not received on central photo-electric cell 103 within a predetermined time such as for example 10 seconds, a warning device or alarm is activated to indicate that there has been a malfunction in the boring apparatus of the present invention. The alarm once activated may be used to interrupt operation of the boring apparatus 2 by stopping the hydraulic motor. The described arrangement has been advanced by way of explanation and many modifications may be made thereto without departing from the spirit and scope of the invention which includes every novel feature and/or novel combination of 5 features hereindisclosed.

In Figures 4 to 8 there is shown another embodiment of the drilling portion of the present invention generally denoted as 120, comprising a main housing 122 having a removable cover 123, a forward support ring frame 124, a rear -10 support ring frame 126, a forward- plate 128 and a rear plate 130. Inside the main housing 122 is located a subassembly 132 for controlling the movement of the main drive shaft 134 and cutting head 136. Sensor 102 is fixedly clamped in position above subassembly 132 to receive the pulsed laser beam from

15 transmitter 17.

An exhaust duct 150 is located longitudinally below subassembly 132 and extends between forward plate 128 and rear plate 130. Subassembly 132 is pivotally attached to main housing 122 by four mounting blocks 138, 140, 142, 144 such

20 that subassembly 132 is free to move upwardly and downwardly with respect to main housing 122 but not sideways. Since drive shaft 134 is journalied in subassembly 132, drive shaft 134 and attached cutting head 136 move upwardly and downwardly with respect to main housing 122 in accordance with

25 corresponding movement of the subassembly 132 (to be described in more detail later) . Additionally, drive shaft 134 is mounted on subassembly 132 in such a manner so as to be capable of sideways movement with respect to the subassembly 132 and to main housing 122 (to be described in more detail

30 later) .

Subassembly 132 comprises a main frame 202 for supporting rotating drive shaft 134. End 208 of rotating drive shaft 134 is connected to universal joint 204 which in turn is connected to universal joint 206 which in turn is

35 connected to other parts of the drive string for rotatingly driving the shaft from hydraulic motor 10 mounted i,n shaft 7 whereas end 210 of drive shaft 134 is connected to the cutting head 136 for cutting the bore 3.

The mechanism for controlling the upwards and downwards movement of the drive shaft 134 and cutting head 136 will now be described.

A first motor 212, preferably an electrically operated motor or similar providing rotary movement, is fixedly attached to main frame 202 on the right hand side towards the rear thereof. The first motor 212 is^~provided with an output shaft having a driving pinion 214 which is meshed with a double reduction gear 216 comprising a pair of gear wheels 216a, 216b and associated pinion gears. The double reduction gear 216 is fixed to one end of transverse shaft 218 which is journalied in a tapered roller bearing 220. Transverse shaft 218 extends between the right hand side of the boring apparatus 120 and the left hand side perpendicularly to the longitudinal axis of the driving shaft. A tapered roller bearing 222 supports the other end of shaft 218. The extreme end of shaft 218 is provided with a first spiral bevel gear 224 which meshes with a second spiral bevel gear 228. First spiral bevel gear 224 is arranged perpendicularly to second spiral bevel gear 228 which form a pair of spiral bevel gears 226 to transmit rotary motion of shaft 218 through 90° to rotary motion of shaft 230 on which is provided second spiral bevel gear 228. Shaft 230 is arranged along the side of the main frame with its longitudinal axis parallel to the longitudinal axis of drive shaft 134. Shaft 230 is journalied in spaced apart pair of tapered roller bearings 232, 234 at one end. Shaft 230 is provided at the end remote from second spiral bevel gear 228 with an externally threaded portion 236 which is received coaxially in an internally threaded sleeve 238. Sleeve 238 moves axially relative to shaft 230 in accordance with corresponding rotary movement of shaft 230 so that as shaft — i ll "

230 rotates sleeve 238 can travel along the length_y of threaded portion 236 because the two threaded portions are threadingly engaged with each other.

Sleeve 238 is integral with rod 240 which is provided with a ring arrangement 242 at its extreme end. Ring 242 is alignedly received between opposed pair of plates 244a, 244b having respective apertures. Pin 246 is received through the pair of apertures and ring 242 when all are aligned. The other end of opposed plates 244a, 244b are each provided with an aperture and are connected in similar manner by a pin 243 passing through their respective apertures when aligned and the aligned aperture of one end of bell crank 248. Bell crank 248 is pivotally connected to mounting block 138 by pin 252 located at the other end of bell crank 248. Transverse shaft 254 is received through a further aperture located intermediate the ends of the bell crank so that as rod 240 and sleeve 238 move longitudinally, bell crank 248, pivots about pin 252 thus raising or lowering the position of subassembly . 132 with respect to housing 132. Transverse shaft 254 which is parallel to transverse shaft 218 extends transversely between the left hand side and right hand side of main frame 202 and at the right hand side is provided with a bell crank 258 similar to that of bell crank 248. Bell crank 258 is pivotally connected to mounting block 140 by pin 255. Instead of an opposed pair of plates 244a, 244b being connected to the end of the bell crank as is the case for bell crank 248, a longitudinal rod 260 is connected to the end 256 of bell crank 258. Longitudinal rod 260 extends from the rear end to the front end of main frame 202. As bell crank 258 is connected to bell crank 248 by shaft 254 both bell cranks move in unison in accordance with movement of integral sleeve 238 and rod 240. At the front end of main frame 202 a bell crank 261 is provided which is identical to bell crank 258. Bell crank 261 is pivotally mounted on mounting block 142 and is linked to bell crank 258 by rod 260 so that bell cranks 258, 260 also move in unison with each other. _ ^ _

A fourth bell crank 262 which is pivotally mounted on mounting block 144 is provided at the other corner of main frame 206 and is connected to bell crank 26.0 by means of transverse shaft 264. Thus, longitudinal movement of sleeve 5 238 causes longitudinal movement of rod 240 which in turn causes arcuate movement of the ends of bell cranks 248, 258, 261, 262 which in turn causes the whole subassembly 132 to move as a single unit upwards or downwards while maintaining its orientation with respect to main housing 202. Since drive shaft 134 is provided with two universal joints 204, 206, the drive shaft is free to move in accordance with movement of the subassembly 132 yet always be parallel with the main frame 202.

The mechanism for controlling the sideways movement of drive shaft 134 and cutting head 136 with respect to subassembly 132 will now be described.

A second motor means 300 is fixedly located on the right hand side of main frame 202 towards the front of the main frame 202 adjacent the first motor 212. Motor 300 is preferably an electric motor but it is to be noted that any suitable motor means, such as a hydraulic motor/pump arrangement may be employed. Motor 300 controls the sideways movement of the drive shaft 134 with respect to the main frame 202. .Motor 300 is provided with an output shaft having a pinion 302 which meshes with a^' double reduction gear arrangement 304 comprising a pair of gear wheels 306a, 306b and associated pinion gears. The double reduction gear arrangement 304 is fixed to one end of transverse shaft 308 which is journalied in roller taper bearing 360 on main frame 202. Transverse shaft 308 extends between the right hand side and left hand side of the main frame 202 and is also journalied at its left hand side end by a tapered roller bearing 310. The end of the transverse shaft 308 opposite to the double reduction gear arrangement 304 is provided with a pinion gear 312. Pinion gear 312 meshes with idler gear 314 on one side and with idler gear 316 on the other side. Idler 8/02435 _ ₀ _

gears 314, 316 are each connected to the main frame by half shafts 318, 320 respectively. Idler gear 314 meshes with gear wheel 322 which is fixedly carried on shaft 324. Shaft 324 which is counter bored along about half of its length is journalied at either end by roller taper bearings 325, 327. The counter bore of shaft 324 is externally threaded along its length intermediate bearings 325, 327. Shaft 324 is received axially inside internally threaded sleeve_326. The threaded portion of shaft 324 threadingly engages with the internal threads provided on sleeve 326 so that as shaft 324 rotates- sleeve 326 moves axially along the length of shaft 324.

Bearing block 328 is fixedly connected to movable sleeve 326 to extend on either side thereof. Drive shaft 134 is journalied in bearing block 328. As shaft 324 rotates in accordance with rotation of motor 300, sleeve 326 and bearing block 328 move axially along transverse shaft 324 to cause drive shaft 134 to move from side to side.

Returning now to pinion 312 which is meshed with idler gear 316, idler gear 316 meshes with gear wheel 340 which is fixedly carried on transverse shaft 342. Transverse shaft 342 is identical to transverse shaft 324 in that shaft 342 has an externally threaded portion 343 which is threadedly meshed with internal threaded portion of sleeve 344. Rotation of shaft 342 causes sleeve 344 to travel longitudinally along the lengthwise extending axis of shaft 342. Bearing block 346, is fixedly connected to the outside of sleeve 344 and extend on either side and accordingly moves in accordance with movement of the sleeve 344. Drive shaft 134 is received through and journalied in bearing block 346. The other end of shaft 342 is received in a roller taper bearing 348 to support it to the main frame.

Since pinion 312 meshes with idler gear wheels 314, 316, shafts 324, 342 rotate simultaneously and accordingly sleeves 326, 344 move in unison sideways in the same amount thus drive shaft 134 is maintained substantially parallel to the longitudinal sides of the main frame. - 21 -

Sensor 102 mounted on subassembly 132 is.the same as sensor 102 of the embodiment illustrated in Figures 1 to 3 and is in electrical contact with a suitable relay box. Operation of the control of boring portion to 12TT is the same as the operation of control of boring portion 12.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within its spirit and scope.

Advantages of the apparatus and method of the present invention include a more accurately controlled cutting head for forming bores of a more or less even and constant slope which means that the overall slope of sewerage and drainage bores may be lessened to say, up to 1 in 300 or even greater, since there are no flat spots or other interruptions to the smooth flow under gravity of the sewerage.

With particular reference to Figure 9, dry solid waste from the bore 3 is transmitted to the surface using a vacuum system comprising a plurality of exhaust conduits 14 connected together between the boring portion 12, 120 and the sub-assembly 6. Conduit 16 from subassembly 6 is connected to a mobile tanker or other suitable vehicle 400 provided with a suitable vacuum system. Preferably the vacuum system is provided with filter screens. Optionally the boring portion is provided with water sprays for spraying the dry solid waste material to form a slurry in the region of the cutting head to clean the cutting head of waste material.

When the soil through which the bore is being formed is moist or is a water bearing clay the suction pipes of the vacuum sometimes become clogged by the agglomeration of the small particles into a large cohesive mass. Water supplied through small pipes internally with the boring portion can be dispensed to break up the cohesive mass so that the smaller particles can be transported to the surface by the vacuum system. 8/0 - 22 -

In Figures 10 and 11 there is shown a still further embodiment of the boring portion of the present invention. This embodiment is essentially the same as. the embodiment of Figures 4 to- 8. However, the embodiment of Figures 10 and 11 is shown in isolation not connected to the main frame or housing but only showing the essential parts to describe operation of the boring apparatus. The mechanism for raising or lowering the embodiment of Figures 10 and 11 is essentially the same as that of the embodiment of Figures 4 to 8 in that there are four mounting blocks 420, 422, 424, 426 located at each of the four corners of subassembly 428 connected to four bell cranks 430, 432, 434, 436. Mounting blocks 420, 422, 424, 426 are connected to the main frame or housing in use. Hydraulically operated linear actuator or ram 438 is fixedly connected to the left hand side of subassembly 428 towards its rear with the ram arm 440 extending rearwardly. The distal end of ram arm 440 is provided with a yoke 442 connected to one end of bell crank 430. Bell cranks 430, 432, 434, 436 are connected together in an identical manner to that described with reference to the embodiment illustrated in Figure 4 to 8. In operation when ram arm 440 is extended the bell cranks pivot to lower subassembly 428 as a single unit in unison so that the drive shaft 442 is lower but remains parallel to subassembly 428. When ram arm 440 is retracted into ram 438, the bell cranks pivot upwards thus raising subassembly 428 and drive shaft 442.

The mechanism for adjusting the sideways position of drive shaft 442 will now be described. Shaft 442 is journalied in a piar of bearing blocks in a similar manner to the embodiment of Figures 4 to 8. However, hydraulically operated rams 446, 448 are provided to move shaft 442 sideways with respect to subassembly 428. Ram 446 has arm 450 which is connected to bearing block 456 and ram 448 has arm 452 which is connected to bearing block 458. As the two arms extend together shaft 442 is caused to move to the right hand side whilst maintaining its alignment parallel to the longitudinal sides of subassembly 428 and when arms 450, 452 retract simultaneously by the same amount, shaft 442 moves. to the left hand side whilst maintaining its alignment parallel to the longitudinal sides of the subassembly 428. Bearing block 456 slides axially on axle 460 whereas bearing block 458 slides axially on axle 462.

In the embodiment of Figures 12 and 13 which illustrate a boring portion having an articulated casing the essential features different from the embodiments previously described are as follows. Drive shaft 500 is provided at its rear end with a universal joint 502 and at its front end with a further universal joint 504. Shaft 500 is journalied in plate 506 which is fixed to front articulated housing 508. Articulated housing 508 is free to move with respect to main casing 510. A universal jointed fixing bracket (not shown) maintains plate 506 in place yet allows it to pivot slightly. The position of the universal jointed fixing bracket is shown in Figure 13 as 512. First hydraulic cylinder 514 is connected by a universal joint 516 to plate 506. The position of cylinder 514 is shown in Figure 13 as 518. When cylinder 514 extends the top of plate 506 is pushed forwards but the lower part is held in place by the reaction of the bracket at position 512 thus articulated casing 508 is deflected downwards whereas when cylinder 514 is withdrawn the top of plate 506 is pulled rearwardly but the lower part is held in placed by the reaction of the bracket at location 512 thus articulated casing 508 is deflected upwards.

A second cylinder (not shown) for controlling the sideways deflection of articulated casing 508 is also provided. The construction of the second cylinder is the same as that of cylinder 514 except that it is located on the opposite side of plate 506 from the position 512 of the bracket. The location of the second cylinder is denoted as 520 on Figure 13. As the second cylinder at position 520 extends the left hand side of plate 506 is pushed forward but the right hand side is maintained in place by the reaction of the bracket at location 512 thus articulated casing 508 is deflected to the right hand side of the boring portion. When 8/ - 24 -

the second cylinder at location 520 is withdrawn the left hand side of plate 506 is pulled towards the rear but the right hand side is maintained in place by the reaction of the bracket at location 512 thus articulated casing 508 is deflected to the left hand side.

The two cylinders at locations 518 and 520 are in electrical connection with the targets of sensor 522 which is identical to the sensors described with respect to the embodiments of Figures 4^~ to 8 having four targets. Each of the four targets controls the operation of one of the cylinders in one direction. Thus, as the boring head moves out of alignment from the predetermined axis, the pulsed laser beam impinges on one of the targets which in turn causes one of the cylinders to move to deflect articulated casing 508 in the opposite direction to realign the boring head along the predetermined axis.

The apparatus of the present invention because it is accurately and automatically controlled without the need of an operator making adjustments to the precise position of the drilling head, can be used with a vacuum system for removing the waste earth from the bore as soon as it is being produced which is for more economical and quicker than previous apparatus requiring an operator to continually monitor the progress and position of the drilling head.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-.

1. An earth working machine comprising a stationary main body portion having a driving means and a movable earth working portion having an earth working element movable with respect to the earth working portion, said earth working element being driven by the driving means in use at a remote location, a control signal transmitting means fixedly connected to the main body portion and a control signal receiving means fixedly connected^{^}to the earth working portion for receiving the signal from the transmitter, said receiver means being located at a remote location from said transmitting means, said earth working portion being provided with a control means for controlling the position of the earth working element relative to the earth working portion in response to the signal received by the receiving means such that the position of the earth working element is maintained within certain predetermined limits from its desired preselected position in use.

2. An earth working machine according to claim 1 characterised in that the earth working machine is a boring apparatus for boring a bore of a predetermined axis.

3. An earth working machine according to claim 1 characterised in that the boring apparatus has a boring head in which the position of the boring head is controlled by a guidance system having a laser beam transmitter_^ on the stationary portion for transmitting a pulsed laser beam and a sensor connected to a drive shaft, the position of said drive shaft be controlled in a first direction by a first motor means and in a second direction by a second motor means.

4. An earth working apparatus according to claim 3 characterised in that the first direction is substantially vertically upwards and downwards and the second direction is substantially horizontally sideways.

5. An earth working apparatus according to claim 3 in which the first motor means is connected to the drive shaft by a first transmission means and the second motor means is . 88

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connected by a second transmission means, said first transmission and second transmission means connected to a common movable bearing means in which said drive shaft is journalied towards its forward end such that operation of the first motor moves the bearing means in the first direction and operation of the motor means moves the bearing means in the second direction, said drive shaft being fixedly journalied in a second bearing means towards its rear end allowing the drive shaft to more or less pivot about the fixed second bearing means.

6. An earth working apparatus according to claim 3 characterised in that the first motor means is connected to the drive shaft by a first transmission means and the second motor means is connected to the drive shaft by a second transmission means, said first transmission means including a subassembly supporting the drive shaft and means for moving the subassembly as a single unit in a first direction and said second transmission means including a movable bearing means in which the drive shaft is journalied, said movable bearing means being movable with respect to the subassembly for moving the drive shaft in a second direction with respect to the subassembly so that operation of the second motor means causes the drive shaft to move whilst maintaining its alignment with respect to the subassembly.

7. An earth working machine according to claim 6 characterised in that the first and second transmission means comprises at least one externally threaded shaft threadingly received in an outer internally threaded sleeve so that rotation of the shaft causes axial movement of the sleeve longitudinally along the shaft.

8. An earth working machine according to claim 1 characterised in that the outer covering or casing of the boring portion is articulated so that a first forward portion is free to pivot with respect a second more rearward portion to adjust the trajectory of the boring portion in use.

9. An earth working machine according to clqim 3 characterised in that the sensor means comprises a plurality of targets arranged so that there is a single central target surrounded by several peripheral targets, said central target being the normal target, for controlling the boring head along the predetermined axis in use, said several peripheral targets being provided in electrical contact with the motors to control operation of the motors to realign the boring head when the direction and inclination of the boring head reaches the preselected limits away from the determined axis.

10. An earth working machine according to claim 9 characterised in that there are five targets, a single central target surrounded by four peripheral targets, each peripheral target sensing the disalignment of the boring head in one direction such that the pulsed laser beam received by the left hand target controls movement of the boring head to the right, the signal received by the right hand target controls movement to the left, the signal received by the target above the central target controls movement of the boring head downwards, and the signal received by the target below the central target controls movement of the boring head upwards such that when the pulsed laser beam impinges on the peripheral targets the limits of divergence from the predetermined axis have been reached and the respective motor means operates to realign the boring head.

11. A method of boring of an underground bore of predetermined axis using a boring apparatus of the type having a stationary portion provided with a driving means for driving a movable boring portion located at a remote location from the stationary portion along the axis of the bore characterised in that the boring portion is provided with a boring head and the position of the boring head during boring is continually monitored by and reposition in response to a guidance system comprising a laser transmitter fixedly located on the stationary means for transmitting a pulsed signal to a sensor located on the remote movable boring portion such that the pulsed laser beam is used to activate motor means to accurately maintain the position of the boring head within certain predetermined limits from its predetermined axis.