FIELD OF THE INVENTION

The present disclosure relates generally to a clutch mechanism and in one aspect relates to a clutch mechanism for use in the drilling industry for drilling rigs.

BACKGROUND OF THE INVENTION

Drilling is often conducted as part of mining exploration programs to obtain a sample of subsurface geological layers. The drilling method used and size of the drilling rig depends on the type of rock and information being sought. Commonly, core drilling, also known as diamond drilling, or reverse circulation drilling (RVC drilling), is used.

Typically, the drilling rig includes a drill bit positioned at an end thereof for cutting through the rock, and a drill string, comprising coupled lengths of pipe or casing, which occupies the hole made by the drill bit. The drill string is connected to a block and tackle which is in turn attached to a lifting device, such as a winch, on a drill rig trailer or derrick.

The pipe or casing sections used in core drilling are typically around 10 feet long and include a core receiving portion. RVC drilling is different from core drilling, in that it requires larger equipment, including a high capacity air compressor, and the pipe or casing sections used are around 20 feet in length.

As the drill bit moves deeper into the ground additional lengths of pipe or casing are added to the drill string. Each of these pipes or casings including a threaded male lower end, commonly referred to as the pin, and a cooperatively threaded female upper end, commonly referred to as a box for engagement with adjoining sections. In this way adjoining pipes or casings can be reversibly coupled together.

In use, after the first 10-20 feet is drilled, a new section of pipe is screwed into the top end, and the combination of pipes can then be driven another 10-20 feet into the ground. This process is repeated until the desired depth is reached or drilling has to be terminated. During assembly or make-up, an additional pipe or casing is raised using the lifting device and aligned with an underlying pipe or casing of the drill string. The additional pipe of casing is then slowly rotated in a clockwise direction, wherein the pin of the additional pipe or casing engages with the box of the underlying pipe or casing. Typically, this is done under low rotation to avoid applying extraneous torque due to the inertia of the drill head, since this would result in overloading of the joint. Typically, this is undertaken by hand to ensure correct coupling is undertaken.

The joint can then be pre-loaded to maintain box shoulder compression under excessive pullback or bending loads and to inhibit leakage, fretting or premature fatigue failures. This can be done using a large wrench or a powered device.

During disassembly or break-out the lengths of pipe or casing of the drill string are sequentially separated at the joint. Breaking-out may however be problematic due to wear or overloading, meaning that the break-out torque requirement exceeds the original make-up torque applied.

Drill pipe spinner device are used in the screwing or unscrewing of threaded connections that form a continuous drill string. One such spinner is disclosed in U.S. Patent No. 7036396 ( MOEet al), that teaches a spinner, used to rotate a drill pipe during connection thereof, to a drill string or during division of the drill string into individual pipes. The invention aims to reduce damage on the threaded connections (the pin-and-box joints) in the screwing/unscrewing operations.

One issue with conventional spinners is that wind up can occur within the drill string which may lead to unintentional untightening or overloading of lower joints. Accordingly, it is useful to be able to disengage the spinner from the coupled lengths of pipe or casing.

The reader will appreciate that clutch mechanisms are used in various mechanical devices and drivetrains to selectively couple two parts together. The clutch may be operated manually or automatically to drive different components. Accordingly, although the present invention will be discussed with particular reference to the mining industry, it should be appreciated that other applications of the clutch mechanism of the present invention are possible and are in face envisaged. It should be appreciated that any discussion of the prior art throughout the specification is included solely for the purpose of providing a context for the present invention and should in no way be considered as an admission that such prior art was widely known or formed part of the common general knowledge in the field as it existed before the priority date of the application.

SUMMARY OF THE INVENTION

It is therefore an object of a least one of the illustrated embodiments to provide a clutch for a mechanical drive that has a reduced longitudinal profile. Other objects of the illustrated embodiments are to overcome at least some of the aforementioned problems, or at least provide the public with a useful alternative. The foregoing objects should not necessarily be considered as cumulative and various aspects of the invention may fulfil one or more of the above objects.

In general, the invention could be broadly understood to reside in a clutch for attachment to a torque generating device, the clutch comprising, an annular member including at least two ramp portions, and at least two pins, wherein the annular member being rotatable, whereby the at least two ramps act upon the at least two pins to reversibly couple the at least two pins, to the torque generating device to thereby impart angular momentum to a drive shaft.

The angular momentum imparted to the drive shaft can be used to apply driving movement to a device engaged by or in connection with the drive shaft.

In one aspect of the invention, but not necessarily the broadest or only aspect there is proposed a drive apparatus, comprising: a torque generating device; a planetary gearbox, having a ring gear and a number of planet gears; a clutch including an annular member having a plurality of spaced apart ramps on an upper surface thereof, and a plurality of movable clutch pins held adjacent the upper surface; a drive shaft coupled to the planetary gearbox; and wherein the ramps of the annular member are configured to act upon respective clutch pins to move the clutch pins into engagement with the ring gear of the planetary gearbox or an intermediate member attached thereto, whereby angular momentum is imparted to the drive shaft by the torque generating device. The torque generating device may be an engine or other power unit or driver.

Preferably, a clutch pin is position adjacent a respective ramp. Each of the ramps include a generally planar raised portion and a sloped portion. The sloped portion extending from the raised portion to the upper surface of the annular member in-between an adjacent ramp.

The annular member may be rotated between a first position wherein the clutch pins abut the upper surface of the annular member between the adjacent ramps, and a second position wherein the clutch pins abut the raised portion of respective ramps.

In one form the clutch pins may be biased into abutment with the annular member, or ramp, or a ramp ring.

In the first position, the clutch pins are disengaged from the ring gear or the intermediate member, such that the ring gear is able to freely rotate and the drive shaft is able to independently rotate.

In the second position, the clutch pins are engaged with the ring gear of the planetary gearbox or the intermediate member, such that the ring gear is fixed relative to the clutch pins and angular momentum or driving movement is imparted to the drive shaft by the torque generating device.

Preferably, the annular member is biased by a biasing member to assist with the correct engagement between the clutch pins and ring gear of the gearbox. The biasing member may be a helical spring/s, leaf spring/s or resiliently deformable block/s. In a preferred form, the biasing member is two helical springs that are configured to act upon the annular member.

In one form the clutch further includes a clutch bush, a ring-shaped gear member including slots for housing the respective springs therein, a protrusion attached to, or extending outwardly from, the ring-shaped gear member and clutch washer. The clutch in the present form also including a pinion gear and pinion washer, connected to a gear motor for moving the ring-shaped gear member. The annular member is coupled to the ring-shaped main gear member and is movable under the influence of the biasing member to ensure correct engagement between the clutch pins and gearbox. In the immediately preceding form the gear motor is used to actuate the clutch to move the clutch pins into engagement with the ring gear of the planetary gearbox, to thereby impart angular momentum to the drive shaft.

The drive apparatus may include limit switches that are configured to be engaged by the protrusion attached to, or extending outwardly from, the ring-shaped gear member to thereby control operation of the gear motor.

The gear motor is operated by using a switch, that can be actuated by a user. When the drive apparatus is being used in a drill pipe spinner device, the switch may be located adjacent a handle of the device so that it is ergonomically positioned for ease of use.

In another form the clutch comprises a clutch bush, clutch ring including slots for housing the respective springs therein, a lever, the annular member including the ramps and the clutch washer. In this configuration the lever is manually operated by the user to rotate the annular member and thereby move the clutch pins into engagement with the ring gear of the planetary gearbox.

In one form six clutch pins are configured to each engage one of six ramps on the annular member.

The ring gear of the planetary gearbox, in one form, includes an underside surface having a plurality of curved tracks or slots with intermediate stops. Each of the curved tracks are configured to engages an upper end of a respective clutch pin. The upper end of the clutch pins may be dome shaped and the curved tracks may be correspondingly shaped to accommodate the upper end of the clutch pins. Sides of the stops may be scalloped to abut with the upper end of the clutch pins.

The lower ends of the clutch pins may be generally flat and configured to slidably engage the upper surface and ramps of the annular member. Alternatively, the lower ends may be rounded, dome shaped, oblique, or a combination thereof.

In another form the drive apparatus may include an upper ramp ring intermediate of the pins and a lower ramp ring. This means that the pins push up and down on a generally planar surface, being the top of the upper ramp ring. In another aspect of the invention there is proposed a drill pipe spinner device incorporating the clutch mechanism of any one of the above aspects.

In still another aspect of the invention there is proposed a method of imparting driving movement to a device engaged by or in connection with a drive shaft, including the steps of: providing a drive apparatus in accordance with any one of the above forms; operating the clutch such that the annular member rotates in a first direction to thereby move the clutch pins into engagement with the ring gear of the planetary gearbox connected to the torque generating device, whereby angular momentum is imparted to the drive shaft of the drive apparatus; and further operating the clutch such that the annular member rotates in a second direction, being opposite to the first direction, to thereby disengage the clutch pins from the ring gear of the planetary gearbox, whereby the drive shaft and torque generating device are able to rotate independently.

In another aspect of the invention there is proposed a method of connecting pipe sections of a drill string, including the steps of: attaching a drive apparatus in accordance with any one of the above forms to a first length of pipe section, being connect to, or connectable to a second length of pipe section; operating the clutch such that the annular member rotates in a first direction to thereby move the clutch pins into engagement with the ring gear of the planetary gearbox connected to the torque generating device, whereby angular momentum is imparted to the drive shaft of the drive apparatus during make-up or break-out of the drill string; and further operating the clutch such that the annular member rotates in a second direction, being opposite to the first direction, to thereby disengage the clutch pins from the ring gear of the planetary gearbox, whereby drive shaft and torque generating device are able to rotate independently, to thereby inhibit wind up within the drill string during operation of the drilling rig.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an implementation of the invention and, together with the description and claims, serve to explain the advantages and principles of the invention. In the drawings,

Figure 1 is a perspective view of one embodiment of the drive apparatus of the present invention;

Figure 2 is a cross-sectional view through A-A of the drive apparatus of Figure 1 , illustrating the clutch pins.

Figure 3 is an exploded view of the drive apparatus of Figure 1 ; Figure 4 is a perspective view of the clutch assembly of the drive apparatus of

Figure 1 ;

Figure 5 is an exploded view of the clutch assembly of Figure 4; Figure 6 is a perspective view of the clutch assembly of Figure 4 in a first position, illustrating the positions of the clutch pins between the ramps;

Figure 7 is a side view of the clutch assembly of Figure 6; Figure 8 is a cross-sectional view through B-B of Figure 7; Figure 9 is a perspective view of the clutch assembly of Figure 4 in a second position, illustrating the relative position of the clutch pins at the top of the ramps;

Figure 10 is a side view of the clutch assembly of Figure 9; Figure 11 is a cross-sectional view through C-C of Figure 10; Figure 12a is a schematic view of the clutch assembly of Figure 1 , illustrating the protrusion in a first position;

Figure 12b is a schematic view of the clutch assembly of Figure 12a, illustrating the protrusion in a second position and the springs in a compressed arrangement;

Figure 12c is a schematic view of the clutch assembly of Figure 12b, illustrating the movement of the legs along respective slots under the bias of the springs;

Figure 13 is a perspective view of the clutch housing, illustrating the position of the ring-shaped gear member in the first position;

Figure 14 is a top view of the clutch housing of Figure 13; Figure 15 is a cross-sectional view through D-D of Figure 13, illustrating the protrusion contacting a first limit switch;

Figure 16 is a top view of the clutch housing, illustrating the position of the ring- shaped gear member in the second position; Figure 17 is a cross-sectional view through E-E of the clutch housing of Figure 16, illustrating the protrusion contacting a second limit switch; Figure 18 is a perspective view of the clutch assembly, motor retainer and gearbox of Figure 1 ; Figure 19 is a side view of the clutch assembly, motor retainer and gearbox of Figure 18, illustrating the clutch assembly in the first position; Figure 20 is a cross-sectional view through F-F of Figure 19, illustrating the clutch pins disengaged from the gearbox; Figure 21 is a side view of the clutch assembly, motor retainer and gearbox of Figure 18, illustrating the clutch assembly in an intermediate position; Figure 22 is a cross-sectional view through G-G of Figure 21, illustrating the clutch pins partly engaging the gearbox; Figure 23 is a side view of the clutch assembly, motor retainer and gearbox of Figure 18, illustrating the clutch assembly in the second position; Figure 24 is a cross-sectional view through H-H of Figure 23, illustrating the clutch pins fully engaging the gearbox; Figure 25 is a perspective view of the clutch assembly and motor retainer of Figure 1 , illustrating the position of the clutch pins when the clutch assembly is in the first position;

Figure 26 is a perspective view of the clutch assembly and motor retainer of Figure 1 , illustrating the position of the clutch pins when the clutch assembly is in the second position;

Figure 27 is a perspective view of the drive shaft, clutch assembly, clutch pins and gearbox of Figure 1, illustrating the clutch assembly in the first position;

Figure 28 is a side view of Figure 27; Figure 29 is a cross-sectional view through l-l of Figure 28; Figure 30 is a perspective view of the drive shaft, clutch assembly, clutch pins and gearbox of Figure 1, illustrating the clutch assembly in the second position;

Figure 31 is a side view of Figure 30; Figure 32 is a cross-sectional view through J-J of Figure 31 ; Figure 33 is a perspective view of one embodiment of the ring gear of the planetary gearbox;

Figure 34 is a top view of the ring gear of Figure 33; Figure 35 is a cross-sectional view through K-K of Figure 34. Figure 36 is an exploded view of the planetary gearbox of Figure 1 ;

Figure 37 is a second embodiment of the drive apparatus of the present invention illustrating a manual actuator lever;

Figure 38 is a cross-sectional view through L-L of Figure 37;

Figure 39 is an exploded view of the drive apparatus of Figure 37;

Figure 40 is an exploded view of another embodiment of the clutch assembly, having cooperating upper and lower ramp rings;

Figure 41 is an underside view of the upper ramp ring of Figure 40;

Figure 42 is a perspective view of the upper ramp ring of Figure 41 ;

Figure 43 is a side view of the upper ramp ring of Figure 41 ;

Figure 44 is a top view of the lower ramp ring of Figure 40;

Figure 45 is a perspective view of the lower ramp ring of Figure 44;

Figure 46 is a side view of the lower ramp ring of Figure 44;

Figure 47 is a perspective view of the cooperating upper and lower ramp rings in a first position;

Figure 48 is a side view of the cooperating ramp rings of Figure 47;

Figure 49 is a cross-sectional view through M-M of Figure 47;

Figure 50 is a perspective view of the cooperating upper and lower ramp rings in a second position;

Figure 51 is a side view of the cooperating ramp rings of Figure 50;

Figure 52 is a cross-sectional view through N-N of Figure 50;

Figure 53 is a perspective view of the cooperating upper and lower ramp rings in a third position;

Figure 54 is a side view of the cooperating ramp rings of Figure 53; and

Figure 55 is a cross-sectional view through 0-0 of Figure 53.

DETAILED DESCRIPTION OF THE ILLUSTRATED AND EXEMPLIFIED EMBODIMENTS

Similar reference characters indicate corresponding parts throughout the drawings. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration.

Referring to the drawings for a more detailed description, there is illustrated a clutch mechanism 10, demonstrating by way of examples, arrangements in which the principles of the present invention may be employed. The reader will appreciate that the invention broadly relates to a clutch mechanism 10 that can be incorporated into various apparatus, such as but not limited to, a drill pipe spinner device used in screwing and unscrewing pipe sections of a drill string.

Figure 1 illustrates one embodiment of a drive apparatus 12 incorporating the clutch mechanism 10 of the present invention. The drive apparatus 12 includes a torque generating device 14, a gearbox 16, clutch mechanism 10 and a drive shaft 18. As illustrated in Figures 1 to 3, the drive apparatus 12 includes main housing parts 20, 22, a clutch housing 24, an end cap 26 and a motor retainer 28.

As illustrated in Figures 2 and 3, the clutch mechanism 10 comprises, an annular member or ramp ring 30, including ramps 32. Clutch pins 34 are movable by way of the ramps 32 of the annular member 30, whereby clutch pins 34 are engageable with the gearbox 16, to thereby impart angular momentum to the drive shaft 18.

Figure 3 illustrates the components of one embodiment of the drive apparatus 12, wherein the clutch mechanism 10, further includes a clutch bush 36 and ring- shaped gear member 38 including slots 40 for housing respective springs 42 therein. A protrusion or gear key 44, is attached to the ring-shaped gear member 38 and a clutch washer 46 is positioned thereabove.

The clutch mechanism 10, in the present embodiment also including a pinion gear 48 with pinion washer 50, that is connected to a gear motor 52 for moving the ring-shaped gear member 38. The gear motor 52 is attached to the clutch housing 24 by way of clamp 54 held in place by screws 56.

Limit switches 58, 60, are connected to the clutch housing 24, which are configured to be engaged by the protrusion 44 to thereby control operation of the gear motor 52. The reader will appreciate that the gear motor 52 is turned on and off using a switch (not shown), that can be actuated by a user.

The gearbox 16, is a planetary gearbox, as will be described with reference to Figure 36, and is housed within gearbox housing 62, show in Figure 3. The torque generating device 14, in the present embodiment is an electric motor including a rotor 64 and a stator 66. The electric motor 14 is preferably connected to a power source (not shown). For instance, where the drive apparatus 12 is for use in a drill pipe spinner device (not shown) a rechargeable battery may be attached, thereto, as disclosed in Australian Innovation Patent No. 2020100770, which is incorporated herein by reference.

The drive apparatus 12 is assembled using various fixing means, such as but not limited to, socket head cap screws, 68, 70 and 72.

Turning to Figures 4 to 12b there is illustrated the clutch assembly 10 illustrating the operation thereof. Figures 4 and 5, illustrate the annular member or ramp ring 30, clutch bush 36 and ring-shaped gear member 38 in greater detail. As the reader will appreciate the ramp ring 30 includes six ramps 32 spaced apart around the upper surface thereof. Two legs 74 depend downwardly from the ramp ring 30 and are configured to slidably engage a respective slot 40 in the ring-shaped gear member 38. The biasing springs 42 are held within respective slots 40 such that they act upon a respective leg 74 to bias the ramp ring 30 to ensure correct engagement between the clutch pins 34 and the gearbox 16, as will be discussed with reference to Figures 33 to 35.

The protrusion or gear key 44 may be connected to the ring-shaped gear member 38 using a screw (not shown) that engages aperture 76. As further illustrated in Figure 5, the clutch bush 36 comprises an annular base 78 and a ring- shaped upstand 80.

Figures 6 to 8, illustrate the location of the clutch pins 34 relative to the ramp ring 30 when in the first position. The clutch pins 34 in this position are located between the ramps 32 and abut the upper surface of the ramp ring 30. Each ramp includes a planar raised portion 82 and a sloped portion 84 extending between the raised portion 82 and the upper surface 86 of the annular member 30 between adjacent ramps 32.

As the ring-shaped gear member 38 is moved by way of the pinion 48, the clutch pins 34 slid up the sloped portions 84 of a respective ramp 32, onto the planar raised portions 82, as illustrated in Figures 9 to 11. This movement of the clutch pins 34 result in engagement with the underside of the ring gear 88 of the planetary gearbox 16. This engagement essentially locks the ring gear 88 resulting in angular momentum being imparted to the drive shaft 18 from the torque generating device 14. Figures 12a to 12c illustrate the compression of the biasing springs 42 that are used to preload the annular member 30, whereby when the electric motor 14 is engaged the clutch pins 34 can more easily drop into the slots 92 of the ring gear 88 and lock in operation once the electric motor 14 input starts to rotate.

Figures 13 to 17 illustrate the operation of the gear motor 52 for moving the ring-shaped gear member 38, wherein the gear motor 52 is controlled by the limit switches 58, in Figures 13 to 15, and limit switch 60 in Figures 16 and 17.

As the reader will now appreciate, the engagement of the clutch pins 34 with and the ring gear 88 of the planetary gearbox 16, allow for transferral of torque and the disengagement of the clutch pins 34 from the ring gear 88. This permits independent rotation of the drive shaft 18 and electric motor 14, to inhibit wind up, such as may occur within a drill string during operation of a drilling rig.

Figures 18 to 20 and 27 to 29, illustrate the ramp ring 30 in a first position, wherein the clutch pins 34 are positioned between ramps 32 and are therefore disengaged from the ring gear 88 of the planetary gearbox 16. Figures 18 to 20 illustrate the clutch assembly 10 engaging the planetary gearbox 16 and positioned within the motor retainer 28. Figures 27 and 29, illustrate the same orientation of the ramp ring 30, but with the motor retainer 28 removed and the drive shaft 18 attached thereto.

As best illustrated in Figures 20, 28 and 29, the dome shaped upper end 90 of the clutch pins 34 are below and spaced apart from the curved tracks 92 of the ring gear 88 of the planetary gearbox 16. This means that the ring gear 88 is able to freely rotate when torque is applied by the electric motor 14 (torque generating device).

Since the drive shaft 18, which could also be referred to as the output shaft, is free to rotate it will not back drive the motor input. The reader will appreciate that there is no resistance which also means if the motor was to 'drive' the system the ring gear 88 would spin internally and not apply power (rotation) to the output shaft/drive shaft 18.

Figures 21 and 22, illustrate the position of the clutch pins 34 as they slide up the sloped portions 84 of the respective ramps 32. This movement of the clutch pins 34, brings the dome shaped upper ends 90 into engagement with the curved tracks 92 of the ring gear 88 of the planetary gearbox 16, as illustrated in Figure 22.

Figure 23, 24 and 30 to 32, illustrate the position of the clutch pins 34 when they are located on the planar raised portion 82 of the respective ramps 32. In this position the dome shaped upper ends 90 are fully engaged within the curved tracks 92 of the ring gear 88 of the planetary gearbox 16. Accordingly, the output shaft/drive shaft 18 is effectively locked to the input from the electric motor 14. The back-driving results in high resistance and the system acts as a direct drive, wherein the power and torque from the motor is output by way of drive shaft 18.

Figures 23 and 24 illustrate the clutch assembly 10 engaging the planetary gearbox 16 and positioned within the motor retainer 28. Figures 30 and 32, illustrate the same orientation of the ramp ring 30, but with the motor retainer 28 removed and the drive shaft 18 attached thereto.

Figures 25 and 26 illustrate the vertical position of the clutch pins 34 relative to the motor retainer 28 when the clutch assembly is in the first position and in the second position respectively.

The skilled addressee will now appreciate that the clutch mechanism of the present invention provides an effective way of disengaging a motor from a drive shaft, such as may be required in a mining situation to inhibit wind up in a drill string.

Figures 33 to 35 illustrate one embodiment of the ring gear 88 of the planetary gearbox 16 having an underside surface including a plurality of curved tracks or slots 92 with intermediate stops 94. Each of the curved tracks 92 is configured to engage a dome shaped upper end 90 of a respective clutch pin 34. As illustrated best in Figure 33 the sides of the stops are scalloped to abut with the upper end 90 of the clutch pins 34.

The primary reason for the spring mechanism 42 is in the situation where the stops 94 lines up with the clutch pins 34, which would mean that the gear 88 is not able to fully engage and thus would stall and not work. The use of the springs 42 allows preloading, such that when the electric motor 14 engages the clutch pins 34, they are able to easily drop into the slots 92 and lock in operation once the electric motor 14 input starts to rotate. The clutch pins 34 are able to slide along the respective slot 94 until reaching the bump stops 94, this allows an amount of “free play” in the system as well as making it more reliable/repeatable.

Figure 36 illustrates one embodiment of the planetary gearbox 16, including the ring gear 88, a sun gear member 96 that is couplable to an output of the electric motor 14, a number of planet gears 98 and a carrier 100. The carrier 100 includes locating rods 102 for position the planet gears 98 thereon. The planetary gearbox 16 further includes an attachment member 104 to which the output shaft/drive shaft 18 can be splined by way of aperture 106. The attachment member 104 is held in place by a base 108 which has an opening 110 through which the output shaft/drive shaft 18 can extend.

The reader will now appreciate that the input shaft from the electric motor 14 is fixedly connected to the sun gear member 96 and the output shaft/drive shaft 18 is splined into attachment member 104. When clutch pins 34 are disengaged from the ring gear 88, it can rotate freely. Therefore, if sun gear member 96 is rotated by the electric motor 14, it will spin planet gears 98, which will in turn freely spin ring gear 88, but will not affect rotation of carrier 100 or attachment member 104.

Likewise, if attachment member 104 is moved, due to rotation of the output shaft/drive shaft 18, as would occurring during wind up within the drill string, the carrier 100 will rotate, thereby spinning planet gears 98 and ring gear 88, but the sun gear member 96 will remain stationary. This means that the system spins inside and no force is required to back drive.

However, if the clutch pins 34 are engaged it locks the ring gear 88. Accordingly, when sun gear member 96 is rotated it spins planet gears 98 and rotates carrier 100 and thus attachment member 104 for power delivery. In reverse, if attachment member 104 is back driven it rotates carrier 100 and thus planet gears 98, this will rotate sun gear member 96 accordingly and is useful if back drive force through the motor if needed.

Figures 37 to 39 illustrates a mechanical actuation of the clutch mechanism 10, using a clutch lever 112 that is attachable to a mount 114 in a side of a ring- shaped member 116. The ring-shaped member 116 which includes the slots 40 for housing respective springs 42 therein. The reader will appreciate that the ring- shaped member 116 replaces the gear member 38 of the earlier figures. The reader will also appreciate that the clutch housing 24, in the present embodiment includes a slot 118 through which the clutch lever 112 is configured to extend.

In the manually actuated version of the drive apparatus 12, many of the components, such as 30, 34, 36, 45, 98, 108 are the same as previously described. However, as illustrated in Figure 39, components 28, 62, 96, 100, are slightly altered, as would be obvious to a person skilled in the art. The reader will appreciate that the operation of the internal components is generally the same, except for the actuation of the clutch.

The skilled addressee will appreciate that the torque generating device 14 may be an engine, such as but not limited to a combustion engine, or other power unit, or an AC device, or a DC drive.

In its simplest application, the clutch of the present invention connects and disconnects two rotating shafts (i.e. drive shafts or line shafts). In these devices, one shaft is typically attached to an engine or other power unit (the driving member) while the other shaft (the driven member) provides output power for work.

When the drive apparatus 12 is being used to assist in connecting pipe sections of a drill string, it is attached a first length of pipe section to be added to or removed from the drill string. During make-up the length of pipe section and drive apparatus 12 attached thereto are hauled up into the air using a hoist. The first length of pipe is connected to a length of pipe already within the drilled hole and the drill string is lowered further into the hole. The user is then able to grasp the drive apparatus 12 and operate the clutch such that the annular member rotates in a first direction to thereby move the clutch pins into engagement with the ring gear of the planetary gearbox connected to the torque generating device. This results in angular momentum being imparted to the drive shaft to thereby tighten the lengths of pipe together during make-up. During the break-out, the process is reversed to separate the pipe sections.

As the reader will appreciate, when the clutch pins 34 are disengaged from the ring gear 88, the drive shaft 18 and torque generating device 14 are able to rotate independently, to thereby inhibit wind up within the drill string, during operation of the drilling rig. Figures 40 to 55 illustrate another embodiment of the clutch assembly including an upper ramp ring 120 having ramps 122, that cooperatively engage the ramps 32 of the lower ramp ring 30. In the present embodiment, the pins 34 engage against the upper ramp ring 120, which has a similar configuration to the lower ramp ring 30, however does not include legs 74. The upper ramp ring 120 also includes tabs 124 that project out either side on the outer rim, and which are configured to engage with slots (not shown) to thereby allow it so slide up and down freely.

The inclusion of the upper ramp ring 120 intermediate of the pins 34 and lower ramp ring 30 means that the pins 34 push up and down on a generally planar surface, being the top of the upper ramp ring 120, rather than sliding up and down the ramps themselves. This is envisaged to reduce some of the adverse forces that may affect operation of the invention.

The skilled addressee will now appreciate the advantages of the illustrated invention over the prior art. In one form the illustrated embodiments provide a clutch assembly that can be used to reversibly connect two rotating shafts, or a drive to a drive shaft. One particular embodiment that is envisage is a drive apparatus used in the make-up and break-out of drill strings. The present invention provides a clutch assembly that has a low profile and can be incorporated into numerous devices.

Various features of the invention have been particularly shown and described in connection with the exemplified embodiments of the invention, however it must be understood that these particular arrangements merely illustrate the invention and it is not limited thereto. Accordingly, the invention can include various modifications, which fall within the spirit and scope of the invention.