Abstract:
The invention relates generally to a method and a device for lifting and lowering respectively a load, said load having a lifting loop attached to said load. The device comprising: a first member having means for attachment to a lifting device and means for attachment to the lifting loop of said load; a second member having means on said second member for automatically guiding said lifting loop to define a path for coupling and uncoupling of said lifting loop to and from said first member; a securing mechanism on said first member which automatically secures said lifting loop to said first member when said lifting loop engages said first member; and a release mechanism for releasing the securing mechanism to release the lifting loop from the first member.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to a method and a device for lifting and lowering respectively a load which preferably shall be moved to and from a space below the ground or the floor, under a water surface or similar spaces which are difficult to access. In particular the invention relates to submersible pumps and, more particularly, to an apparatus for connecting a lifting tackle to the lifting loop of a submersible pump. 
       BACKGROUND OF THE INVENTION 
       [0002]    It should be noted that reference to the prior art herein is not to be taken as an acknowledgement that such prior art constitutes common general knowledge in the art. 
         [0003]    The term “pump” is used hereinafter to refer to a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action. The term “submersible pump” is used hereinafter to refer to a device which has a hermetically sealed motor close-coupled to the pump body. The submersible pump includes both the pump and motor being submerged in the fluid to be pumped. 
         [0004]    Submersible pumps are usually disposed in deep pits below the level of the liquid to be pumped which, in many cases, is sewage. The pumps are usually lowered into the pumping station along substantially vertical guides fixedly positioned within the pumping station so that the pump outlets may be properly aligned and connected to the outlet pipes of the pumping station without using screws or other manual connecting mechanisms. The pumps are usually lifted from the pumping station by the connection of a hook, wire and winch on a crane truck, directly to the top of the pump. A wire or chain may also be attached to the top of the pump as a backup system, for instance when the well cannot be pumped out and there is no other reasonable way to connect the usual line. These chains typically stretch from the top of the pump and attach to a point close to the top of the pumping station in order to be attached to a lifting device such as a crane. However, it is usually standard practice and required that the well be pumped out before retrieval of the pump begins. 
         [0005]    The primary disadvantage of the chain being permanently attached to the pump is that it is more than likely that the wire or chain will be subject to corrosion and or to fouling caused by sludge or solid particles in particular when used for sewerage pumps. Secondly, the use of the extant chain in the lifting process means the crane boom must be significantly higher to cope with the extra chain length. It could also be problematic when used in deep pumping stations where the cost of wires and chains for each and every pump disposed therein can be considerable. 
         [0006]    In order to overcome this problem a loop or ring was attached to the top of the pump and with the use of a releasable hook attached to the end of crane cable the pump was lifted out of the pumping station. This method also had a number of disadvantages in particular when used in deep pumping stations. Under current practice, the well is firstly pumped empty. In order to hook the loop or ring onto the pump the driver of the crane, usually assisted by another crew member, then manually guides the hook towards the loop on the exposed pump. The essential difficulty in this task is guiding a free-swivelling hook into a very small, non-standard aperture in, critically, the correct orientation. This method is both troublesome, inherently risky and time consuming. 
         [0007]    Moreover, the operator is often subjected to unsafe conditions. Thus, accidents or the threat of accidents occur from time to time which can cause considerable disabilities for the operator. Usually it is a question of fingers or hands getting pinched between the hook and the couple; an operator&#39;s finger and hands can be injured or even completely severed. At times injuries to other parts of the body may occur as a result of the fact that the operator stays within the range of movement of the hook where he can be hit by hooks moving in an uncontrolled manner. 
         [0008]    Potentially the highest risk of personal injury and or serious and costly damage to the equipment comes from an insecure hook-up of the pump. If the connection fails and the pump drops back into the well, there is an instantaneous emission (splash) of remnant sewage from the bottom of the well which could contact the operators, and severe damage to the pump and associated infrastructure. The sudden release of the load on the lifting wire turns the wire and hook into a lethal projectile. 
         [0009]    A typical scenario would be where a sewerage pump is located in a pumping station which is smelly, dirty, often in the dark, and located in a confined space some two to three metres below the ground level or working plane. Under these conditions the workplace involves a number of risks to personnel. As described above the normal practice involves one person operating the crane with a line and hook mechanism, and another person guiding a swivelling hook onto a loop or ring affixed to the top of the submersible pump. 
         [0010]    Clearly it would be advantageous if a connecting device could be devised that helped to at least ameliorate some of the shortcomings described above. In particular, it would be beneficial for a lifting device which improves on these deficiencies in particular in improving the safety and labour required to lift and lower a load from a space below the ground or the floor, possibly below a water surface or similar spaces which are difficult to access. 
       STATEMENT OF THE INVENTION 
       [0011]    According to a first aspect, the present invention provides a device for lifting and lowering a load, said load having a lifting loop attached to said load, the device comprising: a first member having means for attachment to a lifting device and means for attachment to the lifting loop of said load; a second member having means on said second member for automatically guiding said lifting loop to define a path for coupling and uncoupling of said lifting loop to and from said first member; a securing mechanism on said first member which automatically secures said lifting loop to said first member when said lifting loop engages said first member; and a release mechanism for releasing the securing mechanism to release the lifting loop from the first member. 
         [0012]    Preferably, the lifting device may be an overhead lifting device, wherein said first member is releasably suspended from said overhead lifting device in order to lift said load. 
         [0013]    The first member may have a connection means comprising an aperture for receiving a hook suspended from the overhead lifting device. Alternatively, the first member may have a connection means comprising a shackle attached to an aperture in said first member, the shackle being suspended from a chain which is attached to the overhead lifting device. 
         [0014]    Preferably, the device may be adapted to rotate about an axis coaxially aligned with the chain of the overhead lifting device when the means on said second member comes into contact with the lifting loop to guide the lifting loop into contact with said first member to automatically couple said first member to said lifting loop. 
         [0015]    The second member may be bell shaped with an open mouth at a first end and an opening at a second end through which the lifting loop passes to couple said lifting loop to said first member. The second member may further comprise a raised lip located on an inner surface of said second member and extending in an arc from said first end to said second end, wherein as the device is lowered and the lifting loop comes in contact with said lip the second member is rotated about said coaxial axis to automatically align and guide the lifting loop into contact with said first member. The lip may be shaped such that it is formed by two concave sides extending upwardly from the inner surface of the second member to form a raised line extending from the first end to the second end. The raised line formed between the first and second end may be formed in an arc, wherein the arc has a raised centre section located between said first and second end of said second member. 
         [0016]    Preferably, the securing mechanism may comprise a releasably secured pivoted hook which automatically engages the lifting loop when the lifting loop is aligned in contact with the first member for coupling the lifting loop to the lifting device. The securing mechanism may further comprise a locking means comprising a pivotal pin member for engaging and locking the pivoted hook once the pivoted hook is engaged with the lifting loop. 
         [0017]    Preferably, the release mechanism may comprise a release pin pivotally attached to the first member, wherein the release pin has a first end attached to the pivotal pin member and a second end attached to a release means, whereby when said release means is activated the pivotal pin member is rotated away from the pivotal hook to allow the hook to release the lifting loop and removing the load from the lifting device. 
         [0018]    Preferably, the release means may be manually operated and comprises a rope means attached to an aperture in the second end of the release pin, whereby when said rope means is pulled the pivotal pin member is rotated away from the pivotal hook to allow the hook to release the lifting loop and removing the load from the lifting device. 
         [0019]    Preferably, the rope means may comprise a metallic cable. Alternatively, the rope means may comprise a non-metallic cable. 
         [0020]    Alternatively, the release means may be remotely operated and may comprise a disengaging means within said first member and responsive to a signal from a remote location for actuating a linear actuator to rotate the pivotal pin member away from the pivotal hook to allow the hook to release the lifting loop and removing the load from the lifting device. The linear actuator may be electrically operated and is responsive to a disengaging signal detected by a radio receiver within said first member. 
         [0021]    Alternatively, the remotely operated release means may be actuated by hydraulic or pneumatic means for actuating the linear actuator to rotate the pivotal pin member away from the pivotal hook to allow the hook to release the lifting loop and removing the load from the lifting device. 
         [0022]    Preferably, at least one camera may be attached to the first or second member, the lifting device, or the load to be lifted, wherein the at least one camera may be used for directing the connection of the lifting device and the lifting loop by a remote operator viewing the area covered by the at least one camera. 
         [0023]    Preferably, at least one light may be used for illuminating the connection of the lifting device and the lifting loop. 
         [0024]    Preferably, a load measuring device may be connected between the lifting device and the device for lifting and lowering the load for monitoring the load weight. 
         [0025]    Preferably, a feedback system may provide an indication of the status and position of the pivoting hook in relation to the lifting loop. The feedback system may comprise a proximity sensor attached to the pivoting hook for detecting and monitoring the attachment of the first member to the lifting loop. The proximity sensor may be a sonar sensor. 
         [0026]    Preferably, the device may comprise any one or more of a gas detection sensor, a turbidity sensor or a depth measurement sensor. 
         [0027]    Preferably, the device for lifting and lowering a load may be manufactured from an intrinsically safe, anti-sparking material. The device for lifting and lowering a load may be coated with a corrosion resistant paint for use in undersea or mining applications. 
         [0028]    Preferably, the device may further comprise a self-cleaning system used to clean both the device for lifting and lowering the load and the lifting hook. The self-cleaning system may comprise a loop clearing device to remove any foreign materials from the lifting loop. The loop clearing device may be a mechanical clearing means. The self-cleaning system may comprise a high pressure cleaning jet or high pressure cleaning hose. 
         [0029]    Preferably, the device may further comprise a self-inflation means attached to the device for lifting and lowering a load to provide a further means of raising the load. The self-inflation means may be gas powered. 
         [0030]    Preferably, the load may be a submersible pump, and said device for lifting and lowering the submersible pump may be lowered into a pumping station for engagement with the lifting loop of the submersible pump. The submersible pump may be located at a level below a working plane towards the bottom of the pumping station. 
         [0031]    Preferably, the submersible pump may be a sewerage pump. 
         [0032]    In accordance with a further aspect, the present invention provides a device for automatically coupling and uncoupling an overhead lifting device to a load having a lifting loop, the device comprising: a first member having means for attachment to a lifting device and means for attachment to the lifting loop of said load; a second member having means on said second member for automatically guiding said lifting loop to define a path for coupling and uncoupling of said lifting loop to and from said first member; a grip and release mechanism for automatically coupling to the first member for load-lifting purposes and for automatically uncoupling from the first member for load release purposes; and wherein the first member comprises a pivoting pin member that causes operation of the grip and release mechanism; and the device being such that the release part of the grip and release mechanism is operated by the weight of the load. 
         [0033]    In accordance with a still further aspect, the present invention provides a method of lifting a load having a lifting loop and located in a pumping station at a level below a working plane, comprising the steps of: i) attaching a lifting device to an overhead crane; ii) lowering the lifting device connected to the overhead crane, said lifting device comprising a first member having means for attachment to the crane and means for attachment to the lifting loop of the load, and a second member having means on said second member for automatically guiding said lifting loop to define a path for coupling and uncoupling of said lifting loop to and from said first member; iii) engaging the lifting loop with the means on the second member wherein the second member rotates about an axis coaxially aligned with a lifting chain of the crane such that the lifting loop is guided to automatically couple with said first member; iv) securing the lifting loop to the lifting device; and v) operating the crane to raise the load. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]    The present invention will be understood more fully from the detailed description given hereinafter and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken to be limitative to the invention, but are for explanation and understanding only. 
           [0035]      FIG. 1  illustrates a connecting device in accordance with an embodiment of the present invention; 
           [0036]      FIG. 2  shows the connecting device of  FIG. 1  in use attached to the end of a crane to be lowered into a pumping station to remove a pump; 
           [0037]      FIG. 3  shows a bottom view of the connecting device of  FIG. 1 ; 
           [0038]      FIG. 4  show a front plan view of the connecting device of  FIG. 1  with the lifting and locking mechanism removed for clarity; 
           [0039]      FIG. 5  is a sectional view taken along the line A-A of  FIG. 4 ; 
           [0040]      FIG. 6  is a sectional view taken along the line B-B of  FIG. 4 ; 
           [0041]      FIG. 7  shows a three dimensional from above of the connecting device of  FIG. 1  with the lifting and locking mechanism removed for clarity; 
           [0042]      FIG. 8  shows a three dimensional view from below of the connecting device of  FIG. 1  with the lifting and locking mechanism removed for clarity; and 
           [0043]      FIGS. 9 to 11  graphically illustrate the connecting device in use as the device rotates and automatically locates the loop or ring. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0044]    The following description, given by way of example only, is described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments. 
         [0045]      FIG. 1  illustrates a lifting device  10  for lifting a load  14  in accordance with an embodiment of the present invention. The load  14  could be any load but for illustrating the use of the present device  10  is described in relation to a submersible pump  14  for use in pumping sewage from a pumping station  66 . However it should be understood that the present invention is not limited to only this particular use. For example, underground water pumping stations could also utilise the present invention for removing and installing underwater pumps. The device could also be useful in any situation or environment which is hostile to human operation, for example, extreme heat, cold, gaseous atmospheres, confined spaces, difficult access or in a location where dangerous animals may exist. Submersible pumps  14  are usually disposed in deep pits or pumping stations  66  and below the level of the liquid to be pumped which, in this case, is sewerage  67 . The pump  14  is lowered into the pumping station  66  along substantially vertical guides  65  (see  FIG. 2 ) fixedly positioned within the pumping station  66  so that the pump outlets may be properly aligned and connected to the outlet pipes of the pumping station  66 . 
         [0046]    The lifting device  10  consists of two components, a top plate assembly  20  and a guiding member  30 . The design of the underside or inner surface  32  shape of the guiding member  30  allows the top plate assembly  20  and hook  21  to automatically align itself to a bespoke or any standard shaped ring or hook  40  fixed to a submersible pump  14 .  FIG. 1  shows the loop  40  attached to the top of a pump  14  by fixing elements  42 . The loop  40  has two arms  43  extending upwardly from the pump  14  which meet at a pre-determined distance raised above the pump  14  to form a ring or eye  41 . It is the ring or eye  41  which is automatically aligned in the top plate assembly  20  and to which the hook  21  passes through. 
         [0047]    The lifting device  10  is typically suspended from a crane  16  by a chain member  15 . In  FIG. 2  the crane is attached to a vehicle or truck  17 . The crane  16  could be attached to any suitable vehicle to lift a pump  14  out of a pumping station  66  or could be a stand-alone crane or any portable crane unit. Provided the crane is suitable for lifting a pump  14  safely out of a pumping station  66 . 
         [0048]    The crane  16  has a chain or rope  15  suspended from the crane  16  and terminating in a hook  11  which is attached to the lifting device  10 . The hook  11  has a safety latch  12  and a throat opening  13  which receives a shackle  24  which is pivotally connected to the top of the hook  21  of the lifting device  10 . The shackle  24 , also known as a gyve, is typically a U-shaped piece of metal secured with a clevis pin or bolt  23  across the opening. Alternatively the shackle  24  may be a hinged metal loop secured with a quick-release locking pin mechanism. Shackles are used as a connecting link in all manner of rigging systems for industrial cranes. In a further alternative the crane chain  15  may be attached directly to the lifting device  10 . 
         [0049]    In  FIG. 1  the shackle  24  is pivotally connected to the top of the hook  21 . The hook  21  of the top plate assembly  20  is pivoted to the body  25  at a first pivot  22 . The hook  21  is able to pivot between a closed and secured position in which the hook  21  is engaged with the ring or eye  41  of the pump loop  40  and an open position in which the hook  21  releases the eye  41  of the pump loop  40  and the pump  14 . 
         [0050]    While the hook  21  is in the closed or engaged position a locking member or pin  55  maintains the hook  21  in this position until the release mechanism  50  is actuated to release the hook  21  and the load or pump  14 . In  FIG. 1  the release mechanism consists of an actuator arm  53  which is pivotally connected to the locking, member or pin  55  at pivot point  54  on the body  25  of the top plate assembly  20 . A release rope or cord  51  is attached to an aperture  52  located at one end of the release arm  53 . The release rope or cord  51  may simply be looped through the aperture  52  or may be attached to a shackle  56  which is passed through the aperture  52  to secure the rope  51  to the release arm  53 . When the rope  51  is pulled in the direction indicated by arrow A the locking member or pin  55  moves to the position indicated by arrow B which allows the hook  21  to pivot about pivot point  22  to release the pump loop  40 . 
         [0051]    The release rope or cord  51  is either a metallic or non-metallic cable of sufficient strength to allow the release mechanism  50  to be actuated. 
         [0052]    The release arm  53  can only be actuated when the load  14  attached to the hook  21  is either set down on the ground or located in the mounting position within the pumping station  66 . The release mechanism  50  cannot be actuated because the weight of the load and the combined forces of gravity maintain the locking member  55  in the locked or secured position. Once the weight is removed the release mechanism  50  is able to be actuated top release the hook  21  from the loop  40 . 
         [0053]    As described above the release mechanism  50  is a mechanical process using a rope  51  to release the hook  21  when the rope is pulled in the direction of arrow A. It should be understood that a number of other options exist for the release mechanism and the invention is not limited to only a purely mechanical process. Other methods including remote activation are described below. 
         [0054]    In accordance with a further embodiment the release mechanism  50  is a remotely actuated disengaging means located within the top plate assembly  20  and responsive to a signal from a remote control  68  for actuating a linear actuator (not shown). The liner actuator is displaceable between a locked position in which the linear actuator secures the hook  21  and an unlocked position in which the hook  21  is able to rotate way from the lifting loop  40  and releases the load or pump  14 . 
         [0055]    A number of options also exist for the control of the actuation of the linear actuator. A control system is basically a device, or set of devices to manage, command, direct or regulate the behavior of other device(s) or system(s). There are a number of different types of control systems, with many variations and combinations. As described above the term “control system” may be applied to the essentially manual controls that allow an operator, for example, to lock and unlock the hook  21 . Another option which may be used is an automatic sequential control system which may trigger a mechanical actuator to perform the task of controlling the hook  21 . For example various electric, pneumatic or hydraulic transducers may control the linear actuator to automatically and/or remotely secure and release the hook  21  of the lifting device  10 . 
         [0056]    In the case of linear feedback systems, a control loop, including sensors, control algorithms and actuators, is arranged in such a fashion as to try to regulate a variable at a setpoint or reference value. Control systems that include some sensing of the results they are trying to achieve are making use of feedback and so can, to some extent, adapt to varying circumstances. 
         [0057]    The actuator may be electrically operated and responsive to a disengaging signal detected by a radio receiver located within the top plate assembly. Or alternatively the actuator may be either hydraulically controlled or pneumatically controlled as described above. For example, the remotely operated release means is actuated by hydraulic or pneumatic means to actuate the linear actuator to rotate the locking member  55  away from the pivotal hook  21  to allow the hook  21  to release the lifting loop  40  and removing the load or pump  14  from the lifting device  10 . 
         [0058]    In order to automatically locate the loop  40  in the opening  33  of the guiding member  30  a raised lip  35  is located on the inner surface  32 . As shown in  FIGS. 3 to 8  the guiding member  30  consists of an outer surface  31  and inner surface  32  forming a frusto-conical shape with an opening  33  located at one end and a mouth  34  located at the opposite end. On the inner surface  32  the lip  35  is formed by two concave sides  60  extending upwardly from the inner surface  32  to a point at which the two concave sides  60  form a raised edge  36  which extends from the opening  33  at one end to the mouth  34  at an opposite end. The raised edge  36  is formed in the shape of an arc with a centre point raised slightly above a point located at either end of the raised edge  36 . 
         [0059]    The guiding member  30  is attached to the top plate assembly  20  by fasteners secured in threaded holes  61  in the top of the guiding member  30 . The top plate assembly is located within a recess  62  in the top end of the guiding member  30  and secured to the guiding member  30  by the fasteners. 
         [0060]    The opening  33  is formed as a longitudinally extending slot which is shaped to receive the upper end of the pump loop  40  which contains the ring or eye  41 . To secure the pump  14  to the lifting device  10  the hook  21  of the top plate assembly  20  passes through the ring or eye  41  to secure the loop  40  for raising and lowering pump  14 . The other end of the guiding member  30  is formed as an open mouth  34  which is shaped to initially allow a user or operator  64  to easily locate the lifting device  10  in the approximate location of the pump loop  40 . 
         [0061]    It is the design of the raised, lip  35  which provides a surface upon which the pump loop  40  comes into contact with and is automatically guided towards engagement with the hook  21  of the top plate assembly  20 . This will be further described with reference to  FIGS. 9 to 11  below. 
         [0062]    In  FIG. 9  the guiding member  30  is being lowered towards the approximate location of the pump loop  40 . As the guiding member  30  is lowered and under the weight of gravity the guiding member  30  rotates in an anti-clockwise rotation as indicated by arrows A. As shown in  FIG. 10  as the guiding member  30  is lowered further the raised lip  35  comes into contact with the pump loop  40  and at this point the direction of rotation is reversed as indicated by arrow B. The guiding member  30  is now rotating in a clockwise direction and is moving to guide the pump loop  40  towards the opening or slot  33 . As also shown in  FIG. 10  the raised lip  35  is in contact with the pump loop  40 . 
         [0063]    Finally, as illustrated in  FIG. 11  the guiding member  30  continues to rotate in a clockwise direction as indicated by arrow C until the pump loop  40  is aligned with the opening or slot  33 . At this point the guiding member  30  is lowered so that the pump loop  40  passes through the opening or slot  33  and into engagement with the hook  21  of the top plate assembly  20 . The hook  21  then locks into engagement with the ring or eye  41  of the pump loop  40  and the locking member  55  secures the hook  21  in place to safely raise the pump  14 . 
         [0064]    In use and as illustrated in  FIG. 2 , an operator  64  would locate his vehicle  17  in a location such that when his vehicle mounted portable crane  16  is deployed it is able to reach over an access hole of the pumping station  66 . The operator  64  then uses a remote control  68  which enables the operator to remotely and autonomously carry out all operations in safely removing and/or replacing a submersible pump  14 . The submersible pump  14  is usually located below the ground plane or level  63  a distance extending into the pumping station  66 . In most cases the submersible pump  14  is located beneath the level of sewage  67  and a few metres below the ground level  63 . The submersible pump  14  is typically mounted on a pump guide or carriage  65 . 
         [0065]    In order to remove a pump or load  14  from its mounted position the operator attaches a lifting device  10  to the end of the crane  16 . In this example use the lifting device release mechanism  50  is a cable  51  which is also activated and controlled by the crane  16  and the remote control  68 . As described above in relation to  FIGS. 9 to 11  the lifting device  10  is lowered into the pumping station  66  and aimed at a position which the operator  64  approximates as to the location of the pump loop  40 . As the lifting device is lowered it is free to rotate in any direction or may not rotate at all. However to explain simply with the use of  FIGS. 9 to 11  the lifting device as lowered in this instance is rotating in the direction of arrow A. Until the guiding member  30  comes into contact with the pump loop  40  it will continue to rotate in the direction of arrow A. At this point the direction of rotation is reversed and the pump loop  40  is automatically guided into the correct position for securing the load  14  to the lifting device  10 . Once secured the pump or load  14  is raised by the crane  16  and removed from the pumping station for maintenance and/or replacement. 
         [0066]    Due to the nature of the secure connection between the pump  14  and the lifting device  10  any work can be carried out with the lifting device still attached to the pump  14 . However in most cases the pump is removed from the lifting device  10  until it is required to be lowered back into the pumping station  66 . Once the pump or load  14  has been repaired or maintenance has been competed the operator  64  simply re-attaches the lifting device  10  to the pump loop  40  and lowers the pump  14  back into the pumping station as guided by the pump guide or carriage  65 . Once the lifting device  10  is secured to the pump loop  40  the connection cannot be removed until the weight of the device being lifted in this case the pump  14  is seated in position in the pumping station  66  and the weight and therefore the tension has been removed from the crane cable  15 . At this point the release mechanism  50  is actuated and the lifting device  10  is released from the pump loop  40  and the lifting device  10  can then be removed from the pumping station  66 . 
         [0067]    As can be imagined a number of options and different component parts may be interchanged or added to the present lifting device to assist in the removal of a load  14  from a position below the ground level  63 . 
         [0068]    By way of example only some of those options are included in the following text however it should be understood that the present invention is in no way limited to only those devices or components. 
         [0069]    A camera may be positioned on the lifting device  10  in order to monitor the connection between the hook  21  and the pump loop  40 . This allows the operator  64  to remotely operate and view the area covered by the camera. The camera may be mounted on the top plate assembly  20 , the guiding member  30  or to a position located towards the end of the crane chain  15 . The camera is particularly useful when the submersible pump  14  is located beneath the level of sewerage  67  in the pumping station  66  or when there is no clear view of the pump loop  40 . In order to provide lighting in the pumping station  66  a light may also be attached to the lifting device  10  to help illuminate the connection and improve the picture received by the camera. Any type of camera or light may be used for example, the camera may be a wireless camera and the light may be an infrared LED light. 
         [0070]    In order to determine the weight of the load  14  being raised and lowered by the crane  16 , a load cell may be placed between the end of the chain  15  and the lifting device  10 . Typically the load cell is a transducer that is used to convert a force into an electrical signal. This conversion is indirect and happens in two stages. Through a mechanical arrangement, the force being sensed deforms a strain gauge. The strain gauge measures the deformation (strain) as an electrical signal, because the strain changes the effective electrical resistance of the wire. A load cell usually consists of four strain gauges in a Wheatstone bridge configuration. The electrical signal output is typically in the order of a few millivolts and requires amplification by an instrumentation amplifier before it can be used. The output of the transducer can be scaled to calculate the force applied to the transducer. The use of the load cell ensures that the safe lifting weight of the crane  16  is not exceeded. 
         [0071]    As described above the control system used for actuating the release mechanism can also be used to provide feedback as to the position of the connection. For example, as the hook  21  pivots around the pivot point  22  the position of the hook  21  can be monitored and is fed back to the operator to closely monitor the connection process. The use of feedback is typically a process in which information about the past or the present influences the same phenomenon in the present or future. As part of a chain of cause-and-effect that forms a circuit or loop, the event is said to “feedback” into itself. For example a feedback signal is the measurement of the actual level of the parameter of interest, in this case the actual position of the hook  21  is monitored using a proximity sensor which can be used to detect and monitor the position of the hook  21  in relation to the pump loop  40 . 
         [0072]    The proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. For example, a sonar sensor or ultrasonic sensors which work on a principle similar to radar or sonar which evaluate attributes of a target by interpreting the echoes from radio or sound waves respectively. 
         [0073]    Any number of sensors may be used in conjunction with the lifting device  10  and in particular, due to the nature of use of the lifting device in sewerage pumping stations  66  any of a gas detection sensor, a turbidity sensor or a depth measurement sensor may also be incorporated in the lifting device  10 . 
         [0074]    Furthermore, due to the nature of the environment in which the lifting device  10  is used, the material from which the device  10  is manufactured must be both an intrinsically safe, anti-sparking material and is coated with a corrosion resistant paint. 
         [0075]    Also, the lifting device  10  includes the ability to be self-cleaning or includes apparatus which provides for self-cleaning. This can be either a high pressure cleaning jet or as high pressure cleaning hose which can be incorporated with the lifting device  10 . The cleaning device can be used to clean the actual lifting device itself or may be incorporated to also clean the pumping station  66  as the lifting device  10  is raised and lowered into and out of the pumping station  66 . Also due to the nature of use in a sewerage pumping station  66  there is also a problem with the pump loop  40  becoming fouled with foreign material and therefore the lifting device  10  may also include a mechanical loop clearing device. 
         [0076]    Should for some reason the cable for attaching to the crane was to break then a flotation device fitted to the lifting device  10  could be inflated to float the lifting device to the surface of the sewerage pumping station for recovery of the lifting device  10 . In order to inflate the device  10  a gas tank would also be incorporated with the flotation device. 
       Advantages 
       [0077]    Basically, the device has been designed in order to overcome the difficulty of manually guiding a hook onto the ring atop the pump and attaching it securely for safe lifting out of the confined space for servicing and repair. 
         [0078]    The design of the underside shape of the device allows the hook to automatically align itself to a bespoke or any standard shaped ring fixed to a submersible pump. The action of the hook is assisted by its own weight under gravity to find the correct orientation of the ring and dock securely in one motion. When the ring is properly located in the hook, the device secures the ring so that it cannot slip off the hook and the pump can then be lifted safely. When returning and lowering the pump back into the pumping station, the device can be easily released remotely and therefore maintaining safe work practices at all stages of the operation. 
         [0079]    The device has been designed to greatly reduce the effort involved in retrieving submersible pumps from their standard operating location at varying distances below ground level. With this device one operator can guide the hook to the ring from above the open sewer well. The design of the underside of the device means the operator need only roughly align the hook vertically above the ring, then lower the line. The action of gravity combined with the shape of the underside curve of the device automatically aligns the hook onto the loop or ring and secures it for safe lifting. 
         [0080]    Furthermore, the pump is held securely in both raising and lowering due to the design of the release. The release can only be operated when the weight of the load is removed from the hook. For example, when the pump is sitting in position in the sewerage station. 
       Variations 
       [0081]    It will be realized that the foregoing has been given by way of illustrative example only and that all other modifications and variations as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth. 
         [0082]    In the specification the term “comprising” shall be understood to have a broad meaning similar to the term “including” and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term “comprising” such as “comprise” and “comprises”.