Actuating mechanism

Abstract

An actuating mechanism ( 111 ) comprising an inner member ( 113 ) and an outer member ( 115 ) axially slidable relative to each other, the inner and outer members ( 113, 115 ) cooperating to define an internal passage ( 117 ) for the flow of a fluid therethrough. The inner member ( 113 ) being configured such that upon a predetermined change in pressure between a first region ( 119 ) and a second region ( 120 ) the actuating mechanism ( 111 ) is caused to move between a first condition and a second condition.

1 - 84 . (canceled) 
   
   
       85 . An actuating mechanism comprising:
 an inner member and an outer member axially slidable relative to each other, the inner and outer members cooperating to define an internal passage for the flow of a fluid therethrough;   the inner member being configured such that upon a predetermined change in pressure between a first region and a second region the actuating mechanism is caused to move between a first condition and a second condition.   
   
   
       86 . The actuating mechanism according to  claim 85  wherein the first region is in the internal passage of the actuating mechanism. 
   
   
       87 . The actuating mechanism according to  claim 85  wherein the second region is external of the actuating mechanism. 
   
   
       88 . The actuating mechanism according to  claim 85  wherein the pressure in the second region is transmitted to a third region located within the actuating mechanism, such that a change in pressure in the second region affects the pressure in the third region. 
   
   
       89 . The actuating mechanism according to  claim 88  wherein the third region is located substantially between the inner and outer members. 
   
   
       90 . The actuating mechanism according to  claim 88  wherein at least a section of the inner member is exposed to both the first and third regions. 
   
   
       91 . The actuating mechanism according to  claim 88  wherein an inner surface of the inner member is exposed to the first region and an outer surface of the inner member is exposed to the third region. 
   
   
       92 . The actuating mechanism according to  claim 88  wherein the actuating mechanism is caused to move between its first and second conditions when the pressure difference between the first region and third region reaches a predetermined value, due to the unequal forces being exerted across the inner member. 
   
   
       93 . The actuating mechanism according to  claim 85  wherein the inner member and outer members are in the form of pipes. 
   
   
       94 . The actuating mechanism according to  claim 85  wherein the inner member comprises a wash pipe having a first end with an outer diameter larger than an outer diameter at a second end, the wash pipe has a portion having a tapered outer diameter. 
   
   
       95 . The actuating mechanism according to  claim 94  wherein the wash pipe has a first seal assembly located along the outer diameter adjacent the first end and a second seal assembly located along the outer diameter adjacent the second end. 
   
   
       96 . The actuating mechanism according to  claim 95  whereby varying the cross sectional diameter of an at leak one seal of the second seal assembly varies pressure differential required between the first region and the second region to operate the actuating mechanism. 
   
   
       97 . The actuating mechanism according to  claim 95  whereby an internal portion of the outer member against which the second seal assembly slidingly engages can be varied according to changes in cross sectional diameter of the at least one seal in the second seal assembly. 
   
   
       98 . The actuating mechanism according to  claim 85  wherein a cavity is defined between the inner member and outer member, the cavity being filled with a lubricant such as oil. 
   
   
       99 . The actuating mechanism according to  claim 98  wherein the cavity has an opening which opens into a chamber of an equalising device. 
   
   
       100 . The actuating mechanism according to  claim 99  wherein the equalising device is in the form of a floating sleeve which is slidingly retained on an outer portion of the outer member and which surrounds the chamber, whereby volumetric changes in the cavity result in the floating sleeve moving with respect to the opening. 
   
   
       101 . The actuating mechanism according to  claim 100  wherein the floating sleeve is in communication with the second region such that pressure in the second region is transmitted to the cavity. 
   
   
       102 . The actuating mechanism according to  claim 96  wherein the cavity provides the third region. 
   
   
       103 . The actuating mechanism according to  claim 96  wherein the cavity is sealed from the internal passage such that the cavity may not be contaminated. 
   
   
       104 . The actuating mechanism according to  claim 85  wherein the actuating mechanism comprises an indexing mechanism which indexes between a first position, wherein the actuating mechanism is in the first condition and a second position wherein the actuating mechanism is in the second condition. 
   
   
       105 . The actuating mechanism according to  claim 104  wherein the indexing mechanism is located between the first and second members. 
   
   
       106 . The actuating mechanism according to  claim 104  wherein the indexing mechanism operates within the cavity. 
   
   
       107 . The actuating mechanism according to  claim 104  wherein the indexing mechanism comprises an indexing sleeve, a travel stop and a positioning sleeve. 
   
   
       108 . The actuating mechanism according to  claim 107  wherein the indexing sleeve is fixed rotationally to the inner member. 
   
   
       109 . The actuating mechanism according to  claim 107  wherein the indexing sleeve is axially movable relative to the inner member. 
   
   
       110 . The actuating mechanism according to  claim 107  wherein the travel stop is mounted on the inner member such that it may rotate about the longitudinal axis thereof, and wherein the travel stop is substantially constrained against axial movement relative to the inner member. 
   
   
       111 . The actuating mechanism according to  claim 107  wherein the positioning sleeve is fixed rotationally to the inner member. 
   
   
       112 . The actuating mechanism according to  claim 107  wherein the positioning sleeve is axially movable relative to the inner member. 
   
   
       113 . The actuating mechanism according to  claim 107  wherein the indexing sleeve and travel stop are biased away from each other. 
   
   
       114 . The actuating mechanism according to  claim 107  wherein the travel stop and positioning sleeve are biased away from each other. 
   
   
       115 . The actuating mechanism according to  claim 107  wherein the travel stop is adapted to co-operate with the indexing sleeve during the indexing sequence. 
   
   
       116 . The actuating mechanism according to  claim 107  wherein the indexing sleeve has a first end which provides a bottom face and a second end having a projection, defining a pawl, extending in an axial direction from the periphery of the second end. 
   
   
       117 . The actuating mechanism according to  claim 116  wherein the travel stop has a first end adapted to engage and mesh with the projection on the indexing sleeve and a second end adapted to engage and mesh with the positioning sleeve. 
   
   
       118 . The actuating mechanism according to  claim 117  wherein a first end of the positioning sleeve is shaped to engage and mesh with the second end of the travel stop. 
   
   
       119 . The actuating mechanism according to  claim 117  wherein the second end of the travel stop is configured to provide a plurality of fingers and corresponding slots, which co-act with corresponding fingers and slots integral with the positioning sleeve, wherein each finger and slot of the travel stop terminates in at least one depression or trough, whilst each finger and slot of the positioning sleeve terminates in at least one peak complimentary in shape to the depression/trough so that upon engagement each finger on the travel top aligns with a finger and/or slot on the positioning sleeve depending on whether the indexing mechanism is in its first position or second position. 
   
   
       120 . The actuating mechanism according to  claim 119  whereby when the indexing mechanism is in its first position the fingers on the travel stop align and mate with the fingers on the positioning sleeve, such that the fingers are opposed and when the indexing mechanism is in its second position the slots on the travel stop align and mate with the fingers on the positioning sleeve, whilst the fingers on the travel stop align and mate with the slots on the positioning sleeve, such that the fingers are interlaced. 
   
   
       121 . The actuating mechanism according to  claim 119  wherein the number of peaks/troughs on each finger/slot determines whether the actuating mechanisms cycles between the first condition and second condition. 
   
   
       122 . The actuating mechanism according to  claim 85  wherein the actuating mechanism comprises at least one retention mechanism to releasably retain the actuating mechanism in one condition until the predetermined pressure differential between the first and third regions is reached whereupon the actuating mechanism is able to move from one condition to the other. 
   
   
       123 . The actuating mechanism according to  claim 122  wherein the retention mechanism is a detent, comprising a ball fixed relative to the inner member but biased radially outward from the inner member. 
   
   
       124 . The actuating mechanism according to  claim 85  wherein the outer member may have a first groove and a second groove on its inner surface spaced a distance from each other, whereby the distance there between is substantially equal in length to the axial distance the inner member moves relative to the outer member as the actuating mechanism moves between its first and second conditions. 
   
   
       125 . The actuating mechanism according to  claim 124  wherein each groove is annular with a cross section complimentary to the ball so that the ball can be received therein and hold the inner member relative to the outer member. 
   
   
       126 . The actuating mechanism according to  claim 122  wherein the retention mechanism comprises a ball fixed relative to the outer member and biased radially inward from the outer member, the inner member having a first groove and a second groove on its outer surface spaced a distance from each other substantially equal in length to the axial distance the inner member moves relative to the outer member as the actuating mechanism moves between its first and second conditions. 
   
   
       127 . The actuating mechanism according to  claim 85  wherein the actuating mechanism is incorporated in an apparatus, such as a tool, for actuating the apparatus between first and second operational condition. 
   
   
       128 . The actuating mechanism according to  claim 127  wherein the apparatus is a flushing device, whereby the actuating mechanism causes the flushing device to move between the first operable condition, wherein the flushing device is closed and the second operable condition wherein the flushing device is open. 
   
   
       129 . The actuating mechanism according to  claim 128  wherein an inner sleeve of the flushing device comprises the inner member of the actuating mechanism, an outer sleeve of the flushing device comprises the outer member of the actuating mechanism, and an internal passage of the flushing device incorporates the internal passage of the actuating mechanism. 
   
   
       130 . The actuating mechanism according to  claim 129  wherein the outer sleeve incorporate openings, the openings being blocked from the internal passage when the flushing device is in the closed operable condition, and register with the internal passage when the flushing device is in the open operable condition. 
   
   
       131 . The actuating mechanism according to  claim 128  wherein the flushing device is configured such that the flushing device remains in the selected open or dosed operable condition regardless of any expansive or compressive force. 
   
   
       132 . The actuating mechanism according to  claim 130  wherein the openings provide a flushing outlet, whereby when the flushing device is in an open operable condition a predetermined percentage of the fluid is diverted from the passage to the outside of the flushing device. 
   
   
       133 . The actuating mechanism according to  claim 132  wherein the flushing outlet comprises a plurality of apertures in the inner sleeve, an annular chamber in the outer sleeve and a plurality of nozzles. 
   
   
       134 . The actuating mechanism according to  claim 129  wherein a fluid tight seal is provided between the inner and outer sleeve when the flushing device moves from a closed operable condition to an open operable condition. 
   
   
       135 . The actuating mechanism according to  claim 134  wherein the flushing device comprises an intermediate sleeve located between the inner and outer sleeve between the flushing outlet and the inlet of the flushing device, the intermediate sleeve being adapted to provide the fluid tight seal. 
   
   
       136 . The actuating mechanism according to  claim 127  wherein the apparatus is an under reamer or casing cutter whereby the actuating mechanism causes the under reamer or casing cutter to move between a first operable condition, wherein a cutting device is contained within the under reamer or casing cutter, and a second operable condition wherein the cutting device protrudes from the under reamer or casing cutter to cut as required. 
   
   
       137 . The actuating mechanism according to  claim 127  wherein the apparatus is an under reamer or casing cutter whereby the actuating mechanism causes the cutting device to move between a first operable condition, wherein the cutting device is off, and a second operable condition wherein the cutting device is on. 
   
   
       138 . The actuating mechanism according to  claim 127  wherein the apparatus is an under reamer or casing cutter whereby the apparatus is a valve, such as a ball valve, whereby the actuating mechanism causes the valve to move between a first operable condition, wherein the valve is closed and a second operable condition wherein the valve is open. 
   
   
       139 . A flushing device comprising
 an inner sleeve and an outer sleeve, moveable relative to each other between an open operable condition, wherein a percentage of the fluid passing through a central passage of the flushing device can be diverted through a plurality of flushing outlets, and a closed operable condition, wherein the fluid outlets are blocked from the passage,   an actuating mechanism operable between the inner and outer sleeves, and having first and second conditions which correspond to the open and closed operable conditions, the actuating mechanism being responsive to a fluid pressure differential between a cavity defined between the inner and outer sleeves, and the pressure in the internal passage, for movement between its first and second conditions, whereby the actuating mechanism, when in the first or second condition couples the inner sleeve to the outer sleeve to prevent movement of the inner sleeve relative to the outer sleeve until predetermined value of pressure differential is reached.   
   
   
       140 . A flushing device for flushing diverted fluid upwards into an annular space between a drill stem and a hole, where a slurry passes through a central passage of the flushing device to a drill head, whereupon it reverses direction, passing through the annular space before returning to the surface with cuttings from the drilling process suspended in the return slurry, the flushing device is adapted to change between an open operable condition, whereby a predetermined percentage of fluid is diverted from the passage to the annular space to assist in maintaining a clean bore, and a closed operable condition, whereby the full flow of the slurry is delivered to the drill head, and is configured such that the increase or reduction of pressure in the internal passage relative to the pressure external the flushing device causes an actuating mechanism located in the device to cycle between a first and second condition whereby the flushing device correspondingly cycles through open and closed operable conditions. 
   
   
       141 . A flushing device comprising:
 an inner sleeve, slidingly received in an outer sleeve, the inner and outer sleeves cooperating to define an internal passage for the flow of a fluid, and are permanently coupled such that there is no rotational movement between the two sleeves;   the outer sleeve having a plurality of flushing outlets   an actuating mechanism comprising an inner and outer member, incorporated within the inner and outer sleeves, an internal passage which is common with the internal passage of the flushing device, the actuating mechanism being caused to cycle between open and closed conditions with change in the pressure differential acting upon the inner member;   an indexing mechanism which indexes as a result of the operation of the actuating mechanism, the indexing mechanism indexes between first and second positions such that the flushing device moves between an open operable condition, whereby the plurality of flushing outlets are open for discharging a quantity of the fluid from the internal passage, and a closed operable condition, whereby the plurality of flushing outlets are closed, the operable condition depending on the position of the indexing mechanism.