US3757874A

US3757874A - Drilling apparatus with mast tilting about upper pivot axis fixed against horizontal translation

Info

Publication number: US3757874A
Application number: US00186975A
Authority: US
Inventors: L Claxton
Original assignee: MINDRILL Ltd
Current assignee: MINDRILL Ltd
Priority date: 1971-10-06
Filing date: 1971-10-06
Publication date: 1973-09-11
Anticipated expiration: 1990-09-11

Abstract

A base has rails extending longitudinally thereof and a drilling machine assembly is mounted on the rails for displacement between a drilling position and a hoisting position, the drilling machine assembly including a drilling head operable to grip and rotate an upright drill rod supported from the upper end of an upright mast having its lower end pivotally connected to the assembly for movement of the lower end with the assembly. A mast support is pivotally connected, at an upper pivot axis, to the upper end of the mast and to a ground point fixed relative to the base, the mast support restraining the upper end of the mast against horizontal translational movement. Thereby, upon movement of the drilling machine assembly from the drilling position to the hoisting position and toward the fixed ground point, the mast is tilted about its upper pivot axis from a first substantially upright position to a second relatively tilted position. The rails guide the drilling machine assembly to tilt in the same direction as the mast to cause the drilling head to tilt in the same direction as the mast. Fluid pressure actuators displace the drilling machine assembly along the rails, and the rails include relatively inclined portions to effect the tilting of the drilling machine assembly.

Description

United States Patent [1 1 Claxton Sept. 11, 1973 DRILLING APPARATUS WITH MAST TILTING ABOUT UPPER PIVOT AXIS FIXED AGAINST HORIZONTAL TRANSLATION [75] inventor: Lindsay Graham Claxton, East Brighton, Victoria, Australia [73] Assignee: Mindrill Limited, Preston, Victoria, Australia [22] Filed: Oct. 6, 1971 [21] Appl. No.: 186,975

[52] US. Cl 173/43, 173/29, 175/85 [51] Int. Cl E2lb 15/00 [58] Field of Search 173/29, 46, 42-44;

[56] References Cited UNITED STATES PATENTS 3,244,242 4/l966 Wolff l75/85 X Primary ExaminerErnest R. Purser Attorney-John J. McGlew et al.

[57] ABSTRACT A base has rails extending longitudinally thereof and a drilling machine assembly is mounted on the rails for displacement between a drilling position and a hoisting position, the drilling machine assembly including a drilling head operable to grip and rotate an upright drill rod supported from the upper end of an upright mast having its lower end pivotally connected to the assembly for movement of the lower end with the assembly. A mast support is pivotally connected, at an upper pivot axis, to the upper end of themast and to a ground point fixed relative to the base, the mast support restraining the upper end of the mast against horizontal translational movement. Thereby, upon movement of the drilling machine assembly from the drilling position to the hoisting position and toward the fixed ground point, the mast is tilted about its upper pivot axis from a first substantially upright position to a second relatively tilted position. The rails guide the drilling machine assembly to tilt in the same direction as the mast to cause the drilling head to tilt in the same direction as the mast. Fluid pressure actuators displace the drilling machine assembly along the rails, and the rails include relatively inclined portions to effect the tilting of the drilling machine assembly.

8 Claims, 5 Drawing Figures PATENTEDSEHHBI; 3,757 8 SHEET 2 [1F 3 PATENTED Y I975 SHEEI 3 BF 3 DRILLING APPARATUS WITH MAST TILTING ABOUT UPPER PIVOT AXIS FIXED AGAINST HORIZONTAL TRANSLATION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to drilling apparatus and particularly to core drilling apparatus used in exploratory drilling.

2. Description of Prior Art The invention has particular but not exclusive application to small drilling rigs and is concerned with rigs of the type in which an upright hoist mast is mounted on a drilling machine which can be'moved back and forth between a forward drilling position and a rearward hoisting position. In apparatus of this type the drilling machine assembly usually comprises a drive motor which drives a hoist drum at the rear of the assembly and a drilling head at the front of the assembly. During drilling the machine assembly is located in its forward position and the drilling head is then located directly over the hole being drilled. The drilling head grips and rotates the drill string which extends downwardly through hand the drill rod is supported by a hoisting rope passed over one or more sheaves at the top of the mast and then down to the hoist drum. When the drill string is to be retrieved from the hole, the whole drilling machine assembly is drawn or racked back to its rearward position and the drill string is hoisted directly by the hoist rope past the retracted drilling head.

It is usual to leave the top drill rod engaged with the drilling head during racking back to avoid the necessity to break the water supply and control connection made to it. In conventional apparatus the drilling machine assembly is racked back in a straight line path and it is necessary to recess the top of the mast to prevent fouling by the top of the drill rod. The present invention provides an alternative arrangement which enables use of a mast of relatively simple and light construction.

SUMMARY OF THE INVENTION The invention provides drilling apparatus comprising a base, a drilling machine assembly mounted on the base and including a drilling head and an upright mast pivotally connected at its lower end to the machine assembly and pivotally connected at its upper end to mast support means, wherein the drilling machine assembly can move on the base from a drilling position to a hoisting position by movement which causes the mast to tilt away from its original upright position which movement is also such that the drilling machine assembly rotates to cause the drilling head to tilt in the same direction as the mast. v I

In order that the invention may be more fully explained, one particular embodiment will now be de scribed in some detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings,

FIG. I is a side elevation of a drilling apparatus shown in condition for drilling operations;

FIG. 2 is a side elevation of the apparatus in condition for hoisting operations;

FIG. 3 is an enlarged cross-section generally on the line 3-3 in FIG. 1;

FIG. 4 is an enlarged and part broken view of the bottom part of the apparatus when in the condition of FIG. I; and

FIG. 5 is a view similar to that of FIG. 4 but with the apparatus in the condition of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT tion comprising a drive motor 13 which drives a hoist 14 and a drilling head 16. An upright mast 17 is pivotally connected at its lower end to the machine assembly 1 l by a pivot connection 18. For the most part mast 17 is of light-weight box girder construction comprising longitudinal stringers l9 and lattice bracing members 21, but its lower end is formed by a bracket 22 connected to the machine assembly 11 by a pivot pin forming the pivot connection 18 about an axis 24.

The upper part of mast 17 is pivotally connected at 26 to the upper end of a stay arm 27 which is inclined at an acute angle to the mast and is pivotally connected at its bottom end to an anchor 29 by a pivot connection 28. Anchor 29 is carried by a mount 31 which is fixed relative to the machine base 12 either by being connected directly to it or by being set firmly in the ground. Arm 27 comprises a central girder section 32, a bottom adjustment portion 33 and an upper portion 34. The lower adjustment portion 33 comprises a screw threaded stem 36 clamped to the bottom of the arm portion 32 by lock nuts 37 and screw-fitted into an internal thread socket member 38 which is connected to the anchor 29 by a ball joint forming the pivot connection 28.

The upper part 34 of arm 27 is bifurcated so as to have two end portions 41 extending one to either side of the upper part of the mast and pivotally connected at their upper ends to the mast by a composite pivot pin 42. The composite pivot pin comprises a central tube 43 to which the upper ends of the arm parts 41 are clamped by studs 44. Pivot tube 43 extends through a bearing tube46 which is fixed between side plates, 47 on the upper part of the mast. Thus the mast l7 and stay arm 27 can pivot relative to one another about the axis of the pivot and bearing

tubes

43,46.

A cradle 49 carrying a pair of

head sheaves

50, 51 hangs from the pivot bearing tube 46 at the upper end of the mast. The cradle 49 comprises a frame 52 in which the

sheaves

50, 51 are journalled and a pair of yoke members 53. The yoke members are of generally inverted U-shape and extend over the pivot bearing tube 46 so that the whole cradle 49 hangs freely from the pivot bearing tube and is free to swing under gravity about the axis 48 of the tube. A cable 55 extends from the hoist 14 to the sheave 50. It passes around sheaves 50 and S1 and then downwardly to a connection to the top drill rod whence it supports the drill string.

FIG. 1 shows the apparatus in a condition ready for drilling. In this condition the main part of the mast is vertical and the sheave S1 is positioned directly above the hole being drilled so that the drill string is supported by cable 55 in accurate alignment with thehole.

- For hoisting operations the whole of the machine assembly 11 is drawn back along base 12 and away from the hole to the position shown in FIG. 2. The drilling head 16 is thus drawn back from its position over the hole and the drill rods can be hoisted directly past it. However the sheave 51 should be accurately positioned directly over the hole not only during drilling operations but also during hoisting. It is therefore most desirable that the position of the sheave 51 be in precisely the same position when the drilling machine is drawn back for hoisting operations as when it is in its forward position for drilling. The geometry of the illustrated ar rangement is carefully arranged to produce this result.

It will be seen from FIG. 1 that when the apparatus is in condition for drilling with the machine assembly I I in its forward position, the pivot axis 24 at the lower end of the mast is not vertically below the pivot axis 48 at the top of the mast but is positioned forwardly from such a position through a distance X. Thus although the main part of the mast is vertical the mast effectively serves as a link which is downwardly and forwardly inclined through a small angle. When the drilling machine assembly 11 is pulled back the pivot connectien 18 is moved to a position 57 which is spaced horizontally from the forward position of that pivot point through a distance of 2X. The forward and rear positions of the pivot connection 18 are thus spaced one to either side of, and equally from, a vertical plane through the second position. i

It will be appreciated that the forward and rear positions of the pivot connection 18 both lie on the same circular are centered on the position of axis 48. Therefore the effect of the linking of the mast to stays arm 27 is that the pivot connection 26 at the top of the mast will be in precisely the same place for the two positions of the drilling machine assembly although it may in fact move whilst the machine assembly is being moved between these forward and back positions. The drilling machine assembly could be drawn back away from the hole in a straight horizontal path. In this case the pivot position 26 would in fact move upwardly through the first half of the movement of the assembly and would then return back to its original position. Because the position of the pivot bearing tube 26-is precisely the same for the forward and back positions of the drilling machine the sheave carriage 49 also hangs in precisely the same position although the mast has moved relative to it.

The drilling machine assembly 11 is in fact not drawn back in a straight horizontal path. As can be seen in FIGS. 4 and 5 the assembly 11 is mounted on the base 12 via front support collars 61 and rear support collars 62 which slide on front tubular rails 63 and rear tubular rails 64 fitted to the base. The rear rails 64 are'inclined I upwardly and rearwardly so that the whole of the drilling machine assemby 11 is canted when it is drawn back to its rear position. The arrangement is such that the pivot connection 18 adopts position 57 when the assembly II is drawn back to its fullest extent, i.e., the same position which it would adopt if the assembly were drawn back in a straight line. It will be appreciated that in order to maintain a straight line motion of the pivot joint 18 the machine assembly 11 would have to be mounted on a curvilinear track support. By the provision of the straight support rollers the pivot connection 18 will go through transient positions away from a straight line path but when the assembly has been drawn to its rear-most position the pivot connection 18 is in the position 57 so that the pivot sheave 51 is correctly aligned above the hole.

The canting of the assembly 11 is provided in order to avoid the top of the drill string from fouling the mast during racking back. It is usual to leave the top drill rod 60 engaged with the drilling head during racking back to avoid the necessity to break the water supply and control connections made to it. The top drill rod 60 is unscrewed from the remainder of the drill string and is then drawn back with the drilling head and out of the way before the remainder of the drill string 65 is hoisted as shown in FIG. 2. If the drilling machine assembly 11 were drawn back in a straight path the top of its top rod would foul the top of the mast. However, in the illustrated arrangement the tilting of the drilling machine assembly 11, and therefore the drilling head 16, is sufficient to cant the top drill rod so that it clears the mast.

As will be seen by comparing FIGS. 1 and 2, the drilling head tilts through a rather smaller angle than does the mast as the drilling machine assembly is racked back. When the assembly 11 is in the drilling position the top drill rod 60 is generally parallel with the front face of the mast but when assembly 11 has been racked back it is inclined to the front face of the mast. This is necessary to allow the remainder of the drill string 65 to be hoisted without fouling the top of drill rod 60. The tilting movement of the drilling head 16 in fact appropriates to swinging movement about a pivot located about twice as far away as the top of the mast.

Because of the tilting movement of the machine assembly 11, it is possible to employ a simple box section mast which can be a light-weight construction. If the machine assembly 11 were not canted during racking back it would be necessary to form the mast with a recessed construction to receive the top of the drill rod and this would necessitate a mast of much more complicated and heavier construction.

The machine assembly 11 is driven backwardly and forwardly along the

rails

63,64 by operation of a double acting hydraulic ram 66 pivotally connected between the assembly and the base 12. It will be seen that support collars 611, 62 are not cylindrical but their internal surfaces are conically tapered at their

ends

61A, 61B, 62A, 62B and that the rails are mounted between members which define similarly tapered

plugs

68A, 68B, 69A, 698. When the machine assembly 11 is driven forwardly the tapered ends 61A, 62A engage the tapered plugs 68A, 69A whereby the machine assembly is positively located and firmly locked in position merely by maintaining hydraulic pressure of the ram 66. Similarly, the assembly is positively located and firmly locked in its rearward position by the engagement of the tapered surfaces 61B, 628 with the

plugs

68B, 69B There is therefore no need to fasten and unfasten clamping means before and after each racking operation as in conventional apparatus.

I claim:

1. Drilling apparatus comprising, in combination, a base; rail means mounted on said base to extend longitudinally thereof; a drilling machine assembly mounted on said rail means for displacement therealong in opposite directions between a drilling position and a hoisting position; an upright mast having its lower end pivotally connected to said drilling machine assembly for movement of said lower end with said assembly; said drilling machine assembly including a drilling head operable to grip and rotate an upright drill rod supported from the upper end of said mast; and mast support means pivotally connected, at an upper pivot axis, to the upper end of said mast and to a point fixed relative to said base, said mast support means restraining the upper end of said mast against horizontal translational movement; whereby, upon movement of said drilling machine assembly from the drilling position to the hoisting position and toward said fixed point, said mast is tilted about said upper pivot axis from a first substantially upright position to a second relatively tilted position; said rail means guiding said drilling machine assembly to tilt in the same direction as said mast to cause said drilling head and a drill rod gripped therein to tilt in the same direction as said mast.

2. Drilling apparatus as claimed in claim 1, wherein the drilling machine assembly is supported on first and second rail means extending longitudinally of the direction of movement from the drilling position to the hoisting position and disposed one behind the other in said direction but inclined relatively to one another so as to cause the rotation of the drilling machine assembly as it moves from its drilling position to its hoisting position.

3. Drilling apparatus as claimed in claim 2, wherein the first rail means is substantially horizontal and the second rail means is disposed behind the first rail means in said direction and is inclined upwardly and away from the first rail means.

4. Drilling apparatus as claimed in claim 2, wherein the first rail means comprises a pair of rails spaced laterally of said direction and the second rail means comprises a second pair of rails also spaced laterally of said direction.

5. Drilling apparatus as claimed in claim 4, wherein the drilling machine is supported on said first and second pairs of rails by a first pair of support collars encompassing and slidable along said first pair of rails and a second pair of support collars encompassing and slidable along said second pair of rails.

6. Drilling apparatus as claimed in claim 2, wherein said first and second rail means have a relative inclination such that said drilling head is tilted through an angle less than the angle through which said mast is tilted.

7. Drilling apparatus comprising a base, a drilling machine assembly mounted on the base and including a drilling head and an upright mast pivotally connected at its lower end to the machine assembly and pivotally connected at its upper end to mast support means, wherein the drilling machine assembly can move on the base from a drilling position to a hoisting position by movement which causes the mast to tilt away from its original upright position which movement is also such that the drilling machine assembly rotates to cause the drilling head to tilt in the same direction as the mast; said machine assembly being supported by two pairs of support collars encompassing and slidable along first and second pairs of rails disposed one pair behind the other in the direction of movement of said machine assembly but inclined relatively to one another so as to cause therotation of the drilling machine assembly as it moves from its drilling position to its hoisting position; said drilling machine assembly being movable between the drilling position and the hoisting position by operation of power means and capable of being held in each of said positions by the interengagement of wedging surfaces at the ends of the collars and at the ends of the rails with the power means operating.

8. Drilling apparatus as claimed in claim 7, wherein the rails are cylindrical and the collars are annular and the wedging surfaces are conically tapered end pieces on the ends of the rails to engage conically. tapered intemal surfaces of the collars.

'--[30] Foreign Application Priority Data.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Np. 3, Q I Dated September 11, 1973 Inventor(s) Llnds'ay Graham 9112011 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet insert Oct. 6,1970 -Australia 2766 Signed and sealed this 24th day of September 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer Comissioner of Patents FORM po'wso 7 I USCOMM-DC 60876-P69 I I U. 5 GOVERNMENT PIINTI'l G OFFICE 2 Q. -3'S!r

Claims

7. Drilling apparatus comprising a base, a drilling machine assembly mounted on the base and including a drilling head and an upright mast pivotally connected at its lower end to the machine assembly and pivotally connected at its upper end to mast support means, wherein the drilling machine assembly can move on the base from a drilling position to a hoisting position by movement which causes the mast to tilt away from its original upright position which movement is also such that the drilling machine assembly rotates to cause the drilling head to tilt in the same direction as the mast; said machine assembly being supported by two pairs of support collars encompassing and slidable along first and second pairs of rails disposed one pair behind the other in the direction of movement of said machine assembly but inclined relatively to one another so as to cause the rotation of the drilling machine assembly as it moves from its drilling position to its hoisting position; said drilling machine assembly being movable between the drilling position and the hoisting position by operation of power means and capable of being held in each of said positions by the interengagement of wedging surfaces at the ends of the collars and at the ends of the rails with the power means operating.

8. Drilling apparatus as claimed in claim 7, wherein the rails are cylindrical and the collars are annular and the wedging surfaces are conically tapered end pieces on the ends of the rails to engage conically tapered internal surfaces of the collars.