Abstract:
Articulated lifting device includes a generally orthogonal support frame having a forwardly extending adjustable lifting arm inserted through a sleeve at the top end of a downwardly extending telescopic leg, a plurality of interchangeable load adapters having elongated adapter arms and a connector that connects telescopic leg with any of the load adapters. The connector may be locked to create rigid frame connection or may be unlocked to allow pivotal movement of the connector in relation to the telescopic leg. An adjustable counterweight may be attached to free end of the adapter arm to balance weight of the heavy adapters. The lifting arm has a hookup point in order to suspend the lifting device off a crane or a hoist. The load adapters may thereby be attached to parts of machinery or other loads located under overhanging structures in order to remove or replace thereof.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is entitled to the benefit of Provisional Patent Application Ser. No. 60/244,433, filed Oct. 31, 2000. 
     
    
     
       BACKGROUND  
         [0002]    1. Field of the Invention  
           [0003]    This invention relates to below the hook lifting devices, specifically to an improved lifting device capable of reaching spaces located under overhanging structures or machinery.  
           [0004]    2. Description of Prior Art  
           [0005]    In some instances it is necessary to lift heavy objects which are not directly accessible for the crane or hoist positioned above because of overhanging machinery or structures extending between hook of the hoisting device and the load.  
           [0006]    To make this type of lifting operation possible, the prior art has resorted to the use of three basic types of lifting devices: an unbalanced rigid frames, an unbalanced mechanically or hydraulically adjustable frames and a balanced rigid frames.  
           [0007]    Unbalanced rigid lifting frames utilize a principle of positioning hookup point, generally located at the end of top frame member, directly above center of gravity of the system which includes load and the frame. This type of lifting device is difficult to use because, when detached from load, such device hangs in the awkward position thus making attaching to and detaching from load unsafe and relatively difficult.  
           [0008]    Unbalanced mechanically or hydraulically adjustable frames utilize same principle as rigid lifting frames described above except their configuration can be changed by human operator operating mechanical or hydraulic device in order to control shape of lifting frame. Although this type of lifting device is more preferable than rigid lifting frames, adjustable frames do not provide fixed predetermined positions of frame members in relation to each other thus making process of adjustment slow and tiresome. Because of mechanical and/or hydraulic moving systems such devices are relatively expensive and require additional maintenance. Hydraulically adjustable frames also have hydraulic hoses which limit their movement and create additional safety concerns.  
           [0009]    In order to ensure correct position while being suspended, balanced rigid frames are equipped with counterweights, generally located at one end of top frame member. This type of lifting frames utilizes principle of positioning hookup point of the lifting device, generally located intermediate the ends of top frame member, directly above center of gravity of the object being lifted. Counterweight has to be heavy enough in order to balance total weight of the lifting device thus making said counterweight relatively heavy and also reducing lifting capacity of the system. In order to make such lifting frame adjustable in regard to horizontal reach, counterweight, which is difficult to reach because of its location on the upper frame member, also has to be made adjustable thus significantly complicating construction and operation of lifting device.  
           [0010]    Other disadvantages of the prior art are associated with relatively complicated structure and frame member connections which do not allow quick assembly, disassembly and wide range adjustments often desirable for efficient use and storage of lifting devices.  
         SUMMARY  
         [0011]    In accordance with the present invention a lifting device comprises a generally orthogonal support frame having a downwardly extending telescopic leg and a forwardly extending adjustable lifting arm with a hookup point for connecting to an overhead hoisting device, a plurality of interchangeable load adapters having elongated adapter arms and a connector connecting said orthogonal frame with said adapter arms having means which human operator can manipulate to restrict or to free pivotal movement thereof thereby allowing to make connection to adapter arm rigid, when said adapter is attached to the load, or pivotal, as necessary for precise positioning and handling of lifting device prior to and after the lift. In a preferred embodiment of present invention, a counterweight assembly is attached to the rear end of adapter arm in order to balance weight of relatively heavy adapters.  
           [0012]    In the construction of present invention, load adapter is directed towards the load and lifting arm of orthogonal support frame extends in the same direction. The lifting arm of the orthogonal support frame may thereby be connected to a suitable overhead hoisting device or a crane. The connector at the bottom of the leg of the support frame may be made free to rotate allowing easy connecting to the adapter arm of the load adapter. After load adapter is attached to the load and connector is connected to the adapter arm, the orthogonal support frame may be rotated about pivot point of the connector in the direction of the load by moving crane above and subsequently locked in a predetermined position thus completing preparation for the lift.  
           [0013]    These and other objects of the present invention will become apparent from a reading of the following specification taken in conjunction with the enclosed drawings 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 shows an elevation of an articulated lifting device being used to remove a water jet from a boat.  
         [0015]    [0015]FIG. 2 shows front elevation of a telescopic leg of an articulated lifting device, drawn to an enlarged scale.  
         [0016]    [0016]FIG. 3 is a side view thereof.  
         [0017]    [0017]FIG. 4 is an elevational view of removable pin.  
         [0018]    [0018]FIG. 5 is a cross-sectional view of the top portion of the telescopic leg.  
         [0019]    [0019]FIG. 6 is an elevation of the bottom/outer part of the telescopic leg.  
         [0020]    [0020]FIG. 7 is an elevation of the top/inner part thereof.  
         [0021]    [0021]FIG. 8 is an elevation of a lifting arm.  
         [0022]    [0022]FIG. 9 is an end view thereof.  
         [0023]    [0023]FIG. 10 is an elevation of a connector.  
         [0024]    [0024]FIG. 11 is an end view thereof.  
         [0025]    [0025]FIG. 12 is a sectional view of a connector taken along the longitudinal axis thereof.  
         [0026]    [0026]FIG. 13 is an elevation of a water jet adapter assembled together with a counterweight assembly.  
         [0027]    [0027]FIG. 14 is an exploded view of a counterweight assembly.  
         [0028]    [0028]FIG. 15 is a cross-sectional view of a tubular arm of a water jet adapter.  
         [0029]    [0029]FIG. 16 is a sectional view of an adapter-to-counterweight arm connection taken along longitudinal axis thereof.  
         [0030]    [0030]FIG. 17 is a cross-sectional view of an adapter tubular arm of a water jet adapter, looking towards an attachment head thereof.  
         [0031]    [0031]FIG. 18 is an unfolding of a rolled plate attachment head of an adapter.  
         [0032]    [0032]FIGS. 19 through 24 illustrate assembly and operation of the preferred embodiment of the present invention.  
         [0033]    [0033]FIG. 19 is an elevational view of an articulated lifting device being assembled with a water jet adapter/counterweight assembly.  
         [0034]    [0034]FIG. 20 is an elevational view of an articulated lifting device, suspended off a crane hook and being prepared for attachment to a water jet which is mounted in a boat.  
         [0035]    [0035]FIG. 21 is an elevational view of articulated lifting device, attached to a water jet, with a telescopic leg fixed in final position and also in the position preceding final (shown in phantom lines), when telescopic leg and connector are pivoted.  
         [0036]    [0036]FIG. 22 is an elevational view of an articulated lifting device, suspended off a crane hook and being moved away from a boat with a water jet attached to it.  
         [0037]    [0037]FIG. 23 is an elevational view of an articulated lifting device being detached and moved away from a water jet which is set in a cradle.  
         [0038]    [0038]FIGS. 24 through 27 illustrate details and operation of additional embodiment of articulated lifting device equipped with an alternative load adapter.  
         [0039]    [0039]FIG. 24 is a side view of a crawler drive adapter being attached to a drive of a crawler tractor supported on wooden blocks in a maintenance shop, with a crawler removed and a drive ready for replacement.  
         [0040]    [0040]FIG. 25 is an end view of a crawler drive adapter.  
         [0041]    [0041]FIG. 26 is an elevational view of an articulated lifting device ready to be attached to a drive adapter.  
         [0042]    [0042]FIG. 27 is an elevational view of an articulated lifting device with a crawler drive attached to it shown suspended off a crane hook and being moved away from a tractor. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0043]    In FIG. 1, an articulated lifting device  30  of the present invention is shown as being used to remove a water jet WJ from a boat B, which is supported on wooden blocks in the dry dock or on shore. Aft of a boat B overhangs water jet WJ, thus making the water jet inaccessible directly from a hook H of a lifting mechanism above. Articulated lifting device  30  is a frame that consists of an adjustable lifting arm  32 , also shown in a greater detail in FIGS.  8 - 9 , that is inserted in a sleeve  33  at the top of a telescopic leg  34 , shown in greater detail in FIGS.  2 - 5 , thus creating a rigid connection that also allows adjustment of the lifting arm extension. A removable pin  35 , which is inserted through sleeve  33  and lifting arm  32 , prevents the lifting arm from sliding within sleeve  33 . A connector  36 , shown in greater detail in FIGS.  10 - 12 , is rigidly connected to the bottom of telescopic leg  34  with removable pin  35 , also shown in FIG. 4, and a pin  37 . In the preferred embodiment, the pin  37  is a bolt with a lock nut which is inserted through connector  36  and telescopic leg  34  in such a manner that allows free rotation of connector  36  around pin  37  when removable pin  35  is not installed. In the preferred embodiment ⅞″ diameter pins are used.  
         [0044]    Connector  36  can be attached to interchangeable load adapters. Each load adapter would be specifically designed to fit certain parts or loads that need to be lifted. In the described embodiment, a water jet adapter  38 , which is presented in detail in FIGS.  13 ,  15 - 18 , is shown attached to the bottom of connector  36  with two removable pins  35 . Heavy load adapters, such as water jet adapter  38 , that cannot be manually handled due to their excessive weight, can be moved into position and attached to the load with the help of the articulated lifting device, which is the subject of this invention, equipped with an adjustable counterweight assembly  39  to balance the weight of such load adapter. Counterweight assembly  39  is adjusted to keep water jet adapter  38  level for the ease of attachment to water jet WJ as illustrated in FIGS.  20 - 21  and as explained below in the section entitled “Operation of Preferred Embodiment”.  
         [0045]    [0045]FIGS. 2 and 3 show elevation (front) and side view of telescopic leg  34  respectively. Telescopic leg  34  comprises an outer tube  40  and inner tube  42  that telescopes within outer tube  40 . In a preferred embodiment both tubes are rectangular cross section. A removable pin  35  (FIG. 4) is inserted in aligned holes through tubes  40  and  42 , thereby assembling the tubes together. Removable pin  35  has machined head  44  with a groove that conforms to the shape of fingers to facilitate removal and installation of the pin. Quick Release Ball Lock Pin (not shown), as supplied by Reid Tool Supply Company R fits in cotter pin hole  45  to prevent accidental fallout of pin  35  and to facilitate easy removal and installation of the pin. FIGS. 6 and 7 show details of outer tube  40  and inner tube  42 . Outer tube  40  has a hole  46 ; correspondingly, tube  42  has a plurality of vertically spaced apart holes  47 . By aligning hole  46  of outer tube  40  with one of the holes  47  of inner tube  42  and inserting pin  35  through aligned holes the overall length of telescopic leg  34  can be adjusted. A plate  41 (FIGS.  2 - 6 ), which has a cutout that is slightly larger than the exterior dimensions of inner tube  42  is welded to the top end of outer tube  40 . The purpose of plate  41  is to center inner tube  42  within outer tube  40  at the top of the outer tube. Plate  48 , welded at the bottom of inner tube  42  as shown in FIG. 7, conforms to interior dimensions of outer tube  40 , only slightly smaller, to allow free movement within outer tube  40  and to center the bottom end of inner tube  42  inside outer tube  40 .  
         [0046]    Sleeve  33  is attached to the top end of tube  42  as shown in FIGS.  1 - 3  and  7 . In the preferred embodiment, sleeve  33  comprises 6″×4″ tubular section which is approximately 12″ long and is welded to the top end of tube  42 . End plates  53  are welded to both ends of sleeve  33 . Each of the end plates  53  has a cutout, similarly to plate  41  (see FIG. 5), to accept lifting arm  32 , shown in FIGS. 8 and 9, and to center it within sleeve  33 . Hole  54  (FIG. 7), drilled through the walls of sleeve  33 , aligns with one of the plurality of spaced apart holes  55  (FIG. 8), drilled through the walls of lifting arm  32 , thus making the extension of lifting arm  32  adjustable. Removable pin  35  shown in FIG. 4 is inserted through the aligned holes  54  and  55 , preventing sliding of lifting arm  32  within sleeve  33  (FIG. 1). To adjust lifting arm extension, pin  35  has to be removed, lifting arm  32  has to be pushed in or out to obtain desirable extension and to align hole  54  of sleeve  33  (FIG. 7) with the closest of holes  55  of lifting arm  32  (FIG. 8), then pin  35  is reinstalled to fix lifting arm  32  in desirable position. FIGS. 8 and 9 are elevation and end views of lifting arm  32  respectively which, in the preferred embodiment, comprises a 5″×3″ rectangular tube, approximately 5′ long, with plurality of spaced apart holes  55  drilled through both walls of the tube. A lifting point  56  comprises two plates  57  welded to the opposite side of the tube at the end of lifting arm  32 . A lifting pin  58  comprises a steel bar of cylindrical shape. Lifting pin  58  is inserted through holes in both plates  57  and welded all way around to the plates  57 , thus providing the hook up point for the crane or hoist.  
         [0047]    Outer tube  40  has a pair of spaced apart holes  49  and  50 , as shown on FIGS. 2 and 6. Hole  49  aligns with hole  51  of connector  36  (FIGS.  10 - 12 ) to accept pin  37 , as showm in FIG. 1, thus permanently connecting telescopic leg  34  with connector  36 . In a preferred embodiment, pin  37  comprises a hex bolt with a lock nut. Hole  50 , which in preferred embodiment is located above hole  49  at the bottom part of outer tube  40  (FIGS. 2 and 6), aligns with hole  52  of connector  36  (FIGS.  10 - 12 ) so that removable pin  35  can be inserted. When pin  35  is installed through holes  50  and  52  of outer tube  40  and connector  36  respectively, swivel action of connector  36  is restrained. On the contrary, when pin  35  is removed connector  36  is able to rotate around permanent pin  37  (FIGS. 1, 20 and  21 ). The bottom end of outer tube  40  is rounded, as shown on FIGS. 2 and 6, to facilitate rotation of connector  36 . (In the preferred embodiment the length of telescopic leg  34  can be adjusted between 6′ and 9.5′, the size of outer tube  40  is 6″×4″ with {fraction (5/16)}″ wall and the size of inner tube  42  is 5″×3″ with {fraction (5/16)}″ wall).  
         [0048]    [0048]FIGS. 10 and 11 show elevation and end view of connector  36  respectively. FIG. 12 is a cross-sectional view taken along the longitudinal axis of connector. Connector  36  comprises two spaced apart plates  59  connected together through spacer plate  60  and stop plate  61 , which also limits angle of rotation of the connector. Two spaced apart holes  62  are drilled or punched in each plate  59 . In the preferred embodiment holes  62  align with respective holes  63  of water jet adapter  38 , shown in FIG. 13, to accept two removable pins  35 . This allows easy attachment of the adapters to the connector  36  as well as quick replacement thereof. Reinforcement plates  64  and  64 a (provided with the holes to match holes  62 ) are welded to inside faces of plates  59  in order to strengthen them in the areas around the holes. Bottom edges of plates  64  and  64   a  are beveled to facilitate easy installation of the interchangeable adapters.  
         [0049]    With the reference to FIGS.  13 - 16 , water jet adapter  38  assembles together with counterweight assembly  39  which can be adjusted to balance the adapter with respect to the permanent pin  37  so that it hangs in almost a level position regardless of the position of telescopic leg  34  (FIG. 20). In the preferred embodiment, water jet adapter  38  comprises an attachment head  65  at the end of a round tube  66  which is inserted through a sleeve  73  (FIG. 13). Spaced apart plates  74  are welded to the top of sleeve  73  (FIGS. 15 and 16). Spacer plate  75  is welded between plates  74 . Pair of holes  63  are provided in each plate  74  which align with holes  62  of connector  36  to receive two removable pins  35 . Round tube  66  is rotatably journaled in oil-impregnated bronze bearings  77  within sleeve  73  (see FIG. 16). Two stop rings  76  are welded to round tube  66  at either end of sleeve  73  to keep the sleeve from moving along the tube  66 .  
         [0050]    With the reference to FIG. 14, counterweight assembly  39  comprises a tubular counterweight arm  78 , a round bar  80  (preferably 2″ diameter), weight plates  81  that are threaded on round bar  80  and fixed in the desirable position with spring clamps  82 . (In the preferred embodiment standard olympic size weight lifting hardware is used for counterweight). Outside diameter of counterweight arm  78  is slightly smaller than inside diameter of tube  66  so, it can be inserted into the free end of tube  66  of the water jet adapter (see FIG. 16). End portion of round bar  80  (preferably 2″ 0  diameter) is inserted into the end of counterweight arm  78  and welded to it with circumferential fillet weld (FIG. 14). In order to assemble water jet adapter with counterweight assembly, the end of counterweight arm  78  is inserted into the end of tube  66  and pinned together with a bolt  83  inserted through a hole  79  as shown in FIGS. 13 and 16. Through hole  84  is provided in counterweight arm  78  where a pry bar (not shown) can be inserted in order to turn water jet/counterweight assembly around its longitudinal axis within sleeve  73 . In the preferred embodiment outside diameter of counterweight arm  78  is 2⅝″ that fits inside round tube  66 , outside diameter of which is 3¾″. In the preferred embodiment, total length of counterweight assembly is approximately 5′-6″, approximate total weight of plates  81  is ninety pounds and total length of water jet adapter  38  is approximately 5′.  
         [0051]    With the reference to FIGS. 13, 17 and  18 , attachment head  65  comprises steel plate  70 , rolled into tubular shape. The inside surface of attachment head  70  is lined with rubber or neoprene sheet  71  to prevent damage to the surface of water jet WJ shown in FIG. 1. Cutouts  72  are provided in plate  70  and in rubber liner  71  (see FIGS. 13 and 18). These cutouts engage lifting lugs of the water jet WJ thus attaching water jet adapter  38  to the water jet as shown on FIG. 1. A spreader  67  comprises rectangular tube which is attached to the end of round tube  66 , cross-section of which is shown in FIG. 17, with circumferential fillet weld. Ends of spreader  67  are rounded to conform to the inside surface of rolled plate  70 . Spreader  67  is attached to the inside surface of rolled plate  70  with fillet weld at the end of the rolled plate  70  which is opposite to cutouts  72 . Gusset plates  68  are provided at the center line of spreader  67  to reinforce rolled plate  70  at the connections with spreader  67 . In the preferred embodiment, inside diameter of the attachment head  65  is approximately 25″, that is 1″ bigger then outside diameter of the water jet WJ.  
       OPERATION OF PREFERRED EMBODIMENT  
       [0052]    [0052]FIGS. 19 through 24 illustrate operation of the preferred embodiment of the present invention. Before using the articulated lifting device, position of the Center of Gravity of the Water Jet WJ shall be determined. Knowing the weights of every part of the lifting device and making assumptions in regard to the extension of adjustable lifting arm  32 , the Center of Gravity of the articulated lifting device  30  in combination with Water Jet WJ attached to it, as well as extension of lifting arm  32 , can be found, unless it is already known from previous experience. Extension of adjustable lifting arm  32  shall be such as to position the hook of the crane or hoist directly above the Center of Gravity of lifting device  30  combined with Water Jet WJ while in working position, as illustrated in FIG. 22. Positioning the hook H of the hoist or crane directly above the Center of Gravity of the lifting device and Water Jet combination will assure that Water Jet WJ as well as lifting arm  32  and adapter  38  will be in the position close to level, while suspended off the hook H. When extension of adjustable lifting arm  32  is determined, appropriate mark, indicating extension of the arm  32  for this type of lift, shall be made on its face with a permanent marker for future use in order to eliminate the necessity of finding the Center of Gravity every time the Water Jet is lifted.  
         [0053]    To prepare articulated lifting device  30  it shall be placed on a pallet or floor F. Pin  35 , connecting adjustable lifting arm  32  with telescopic leg  34 , shall be removed and extension of the lifting arm  32  shall be adjusted, then pin  35  shall be reinstalled in aligned holes in the lifting arm  32  and sleeve  33 . The length of telescopic leg  34  can also be adjusted if necessary by removing pin  35 , which connects tubes  40  and  42 , and sliding tube  40  in or out until desirable length of the leg is achieved. Pin  35  shall be reinstalled in aligned holes of the tubes  40  and  42 . Separately, water jet adapter  38  and counterweight assembly  39  shall be connected together by inserting the end of the counterweight arm  78  into the end of tube  66  as shown in FIGS. 13 and 19. Bolt  83  shall be inserted through aligned holes  79  in both counterweight arm  78  and tube  66 , thus connecting them together.  
         [0054]    Referring to FIG. 19, lifting arm  32  and telescopic leg  34  assembly shall be lifted off the floor F with the crane. Connector  36  shall be made free to rotate around permanent pin  37  by removing pin  35  from the holes  50  and  52 . Lifting arm  32  and telescopic leg  34  assembly shall be brought to the water jet adapter  38  assembled together with the counterweight  39  as shown in FIG. 19. The water jet adapter/counterweight assembly shall be connected to the connector  36  with two removable pins  35  inserted through aligned holes  62  and  63  of connector  36  and water jet adapter  38  respectively (refer to FIG. 19) and then lifted off the floor or pallet as shown in FIG. 20. At this point the position of weight plates  81  is adjusted by releasing spring clamps  82  and sliding them along round bar  80  until weight of water jet adapter  38  is balanced and the water jet adapter/counterweight assembly is suspended in the position close to level as shown in FIG. 20.  
         [0055]    [0055]FIG. 20 shows articulated lifting device  30  suspended off hook H of the hoist or crane above (not shown) and ready to be attached to water jet WJ of boat B. While being suspended off the hook H, the articulated lifting device  30  is slowly moved towards the water jet WJ and water jet adapter  38  is lined up with the water jet. At this point the water jet adapter  38  can be rotated around its axis within sleeve  73  with the help of pry bar (not shown) which is inserted in hole  84  of the counterweight arm  78  in order to lineup cutouts  72  of the attachment head  65  with lifting lugs of water jet WJ. Attachment head  65  of water jet adapter  38  is then slid onto the front portion of the water jet WJ and turned counter clockwise with the pry bar inserted through hole  84  of counterweight arm  78  to engage lifting lugs of water jet WJ as shown in FIG. 21. Hook H of the hoist or crane (not shown) is slowly moved in the direction of the boat, as shown in FIG. 21, until telescopic leg  34  is in the vertical position and hole  50  is aligned with the hole  52  of connector  36 . Removable pin  35  is inserted into aligned holes  50  and  52  thus fixing telescopic leg  34  in the position.  
         [0056]    [0056]FIG. 21 shows articulated lifting device  30  attached to water jet WJ of the boat B and ready for the lift. Hook H of the hoist or crane above (not shown) is slowly moved upwards to the take the load off the boat and water jet WJ is disconnected from the boat B. Then articulated lifting device  30  with water jet WJ is slowly moved horizontally, away from the boat (see FIG. 22). After water jet WJ is set in the cradle C shown in FIG. 23, the load is taken off articulated lifting device  30  by slowly lowering hook R Removable pin  35 , that pins together connector  36  with telescopic leg  34 , is removed. Water jet adapter  38 , together with counterweight assembly  39 , is rotated clockwise within sleeve  73  with the help of the pry bar (not shown) which is inserted through hole  84  to disengage lifting lugs of water jet WI which is now set in the cradle C. Hook H of the hoist or crane above is slowly moved away from water jet WJ, thus causing rotation of telescopic leg  34  and adjustable lifting arm  32  around permanent pin  37  until attachment head of water jet adapter  38  is completely off the water jet WJ as shown in FIG. 23. To install water jet WJ back in the boat B, the above procedure is repeated in the reverse order.  
       ADDITIONAL EMBODIMENTS  
       [0057]    Additional embodiment is shown in FIGS. 24, 25,  26  and  27 . FIG. 24 shows a partial end view of crawler tractor T with crawler drive D, which has to be removed for repair or replacement. Drive D has plurality of tapped holes provided in the front plate. A drive adapter  38 a comprises an adapter plate  86  with plurality of matching holes  87 , through which bolts  88  are inserted in order to attach adapter  38 a to drive D, and a tubular adapter arm  85  with a pair of through holes  63 . End view of adapter  38   a  is shown in FIG. 25. The pair of through holes  63  match holes  62  of connector  36  of articulated lifting device  30  as shown in FIG. 26. In the described embodiment adapter plate  86  comprises 9″ diameter 1½″ thick steel plate with four {fraction (13/16)}″ holes drilled to match the pattern of  3 / 4 ″ diameter tapped holes provided in crawler drive D so that four ¾″ diameter bolts  88  can be inserted through holes  87  and screwed into the tapped holes provided in the front plate of drive D (FIG. 24). Adapter arm  85  comprises 5″×3″×{fraction (5/16)}″ 2′ long rectangular tube welded to adapter plate  86  at one end and provided with pair of holes  63  at the other end, which align with holes  62  of connector  36  to accept removable pins  35  as shown in FIG. 27.  
         [0058]    Due to the relatively light weight of the adapter  38   a  (approximately 60 lbs), it can be attached to the drive D manually, without using crane or hoist, therefore the counterweight assembly described in the description of the preferred embodiment is not required and lifting procedure will be different.  
         [0059]    To remove crawler drive D from crawler tractor T using articulated lifting device  30 , drive adapter  38   a  is attached to the crawler drive D with four bolts  88  as shown in FIGS. 24 and 26. Knowing the weight and position of the Center of Gravity of crawler drive D as well as every part of articulated lifting device  30  and making assumptions in regard to extension of adjustable lifting arm  32  position of the Center of Gravity of all parts combined together, which will be suspended off the crane hook H as shown on FIG. 27, can be found, unless required extension of lifting arm  32  for lifting drive D is already known from previous experience. Extension of adjustable lifting arm  32  shall be adjusted accordingly and articulated lifting device  30  is brought to position for attachment to the adapter  38   a  as shown in FIG. 26. At this point connector  36  is free to rotate around permanent pin  37  to facilitate attachment to the adapter  38   a . Articulated lift device  30  is slowly lowered down and attached to adapter  38   a  with two removable pins  35  inserted through aligned holes  62  and  63  in swivel hanger  36  and adapter  38   a  respectively, as shown in FIGS. 26 and 27. Hook H of the crane or hoist above is slowly moved towards the drive D to rotate telescopic leg  34  until it is in vertical position and hole  50  of telescopic leg  34  is aligned with the hole  52  of connector  36 . Removable pin  35  is inserted into aligned holes  50  and  52  (FIG. 26) thus fixing telescopic leg  34  in the position (FIG. 27).  
         [0060]    Hook H of the hoist or crane above is slowly moved upwards, just enough to take load off the body of tractor T and to disconnect crawler drive D from the body. Then articulated lifting device  30  with drive D attached to it is slowly moved horizontally, away from the crawler tractor T (FIG. 27). To install crawler drive D back in the tractor T, procedure, described herein, shall be repeated in the reverse order.  
         [0061]    All of the components and/or materials of the articulated lifting device of the present invention are readily available on the market, and the fabrication and assembly thereof is relatively simple and convenient. Moreover it will be appreciated by those skilled in the art that the dimension and sizes of the various components disclosed herein are not for purposes of limitations but, rather, for purposes of making a complete disclosure to facilitate a review of the present invention by one skilled in the art and ready appreciation of the features and advantages of the invention. It will also be appreciated by those skilled in the art that the articulated lifting device of the present invention can be supplied with various interchangeable adapters that would be able to attach to different parts and/or loads.  
       ADVANTAGES  
       [0062]    From the description above, a number of advantages of the present invention become evident:  
         [0063]    a) Articulated lifting device of the present invention is equipped with lifting arm that is manually adjustable, thus making it possible to use this device to lift loads of various configurations and/or located under overhanging structures of different extension.  
         [0064]    b) Articulated lifting device, described herein, is also equipped with telescopic leg that can be manually adjusted to meet different lift conditions such as low headroom or deep overhanging structures. Adjustments are made by removing and reinstalling only one pin.  
         [0065]    c) Articulated lifting device of the present invention is equipped with connector that freely rotates around a permanent pin thus facilitating attachment of the lifting device to the adapters already attached to the parts intended for lift or enabling heavy adapters, balanced with the counterweights, to be hanging in the desirable position while being attached to the parts or loads to be lifted.  
         [0066]    d) As described above, articulated lifting device of the present invention can be used with numerous interchangeable adapters that would make it possible to use it for great number of loads and lift conditions which would prevent designing, building and maintaining separate lifting devices for every type of lift and/or condition.  
         [0067]    e) Removable and adjustable counterweights can be attached to heavy adapters that would enable moving and using them by suspending them off the articulated lifting device in the desired position that would also facilitate attachment of such adapters to the parts or items intended for the lift.  
         [0068]    f) Unlike prior art, that requires much heavier counterweights for balancing complete lifting device and, sometimes, load itself, present invention uses small counterweight, if required to balance a load adapter only.  
         [0069]    g) If load adapter is required to rotate in order to attach to the part being lifted, it is provided with a round tubular arm which is rotatably journaled in the bearings within the sleeve that can be attached to the connector of the articulated lifting device.  
         [0070]    It will be easily appreciated by those skilled in the art that all these advantages combined will make it possible to use articulated lifting device that is the subject of the present invention in a wide range of applications and conditions.  
       CONCLUSION, RAMNIFICATIONS, AND SCOPE  
       [0071]    Accordingly, the reader will see that articulated lifting device of this invention can be easily adjusted to lift, remove and reinstall wide variety of machine parts and other types of loads located in limited spaces. Furthermore, the articulated Lifting device of this invention has additional advantages:  
         [0072]    simple connections allow quick manual adjustment of the frame dimensions;  
         [0073]    when disassembled, the articulated lifting device requires minimum storage space;  
         [0074]    it can be easily transported and quickly assembled and disassembled;  
         [0075]    most of the elements of the articulated lifting device of the present invention are reusable, new interchangeable load adapters can be fabricated to fit future loads.  
         [0076]    Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. For example, the connector connecting orthogonal frame with the load adapter can have different construction, spring loaded device can be used instead of the removable pin to restrict pivotal action of the connector, etc.  
         [0077]    Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given