Abstract:
A disclosed lift device serves as a work piece handling tool for performing service operations on a mechanical component, such as a power cylinder head of a gas engine compressor. The lift device may be attached to the cylinder head and used to securely and efficiently remove (and install) the cylinder head from the gas engine compressor. The lift device may also provide a free-standing base for holding the cylinder head securely in a manner that provides access for servicing operations. The advantages of the lift device include a single mounting and unmounting operation for the entire duration of the servicing operations.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Patent Application No. 61/466,626, filed on Mar. 23, 2011, entitled “LIFT DEVICE FOR SERVICE OPERATIONS ON MECHANICAL PARTS”, which is incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure relates to a lift device and, more particularly, to a lift device for servicing mechanical parts. 
     2. Description of the Related Art 
     Maintenance and/or repair of industrial machinery may involve delicate handling of massive mechanical parts. For example, service operations on power cylinders of a gas engine compressor may often involve removal of a power cylinder head. The power cylinder head is often a heavy work piece that may be damaged by removal, positioning, and handling during routine service operations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an image showing selected elements of an embodiment of a lift device; 
         FIG. 2  is an image showing selected elements of an embodiment of a lift device; and 
         FIG. 3  is an image showing selected elements of an embodiment of a lift device. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     In the following description, details are set forth by way of example to facilitate discussion of the disclosed subject matter. It should be apparent to a person of ordinary skill in the field, however, that the disclosed embodiments are exemplary and not exhaustive of all possible embodiments. 
     Disclosed herein is a lift device usable as a tool for handling a head of a power cylinder of a large engine, such as a gas engine compressor. The head of the power cylinder head is referred to herein as the “cylinder head” or the “work piece”, while the power cylinder is referred to herein as the “cylinder”. Although the present disclosure is described with respect to a gas engine compressor, the lift device described herein may be used in conjunction with a number of different mechanical parts of various types of large engines. One example of a type of mechanical part that an embodiment of the disclosed lift device is suitable for handling is a power cylinder head of an Cooper-Bessemer type GMV gas engine compressor. 
     Turning now to the drawings,  FIG. 1  depicts an image showing selected elements of an embodiment of novel lift device  100 . In  FIG. 1 , lift device  100  is shown in preparation for removal of cylinder head  200  from cylinder  202 . Cylinder  202  is intended to be representative for various implementations of power cylinders on different types of large engines and/or gas engine compressors. It is noted that a gas engine compressor with which lift device  100  is used may be equipped with multiple instances of cylinder  202 . Thus, service operations described herein for a single power cylinder may involve multiple repetitions when working on a gas engine compressor. Cylinder  202  may be joined to cylinder head  200  at seal surface  204 , which is visible in  FIG. 2  as a circular crack. Pressure may be applied to seal cylinder  202  with cylinder head  200  using studs  206  and mounting nuts  208 , which may be fastened at top portion  201  of cylinder head  200 . 
     As shown in  FIG. 1 , lift device  100  may be comprised of lift frame  102  and stand  110 . Lift frame  102  may comprise three members in a rectangular U-configuration to receive stand  110 . Different embodiments (not shown) of lift frame  102  may incorporate other geometries, such as circular, triangular, and/or based on other polygons. At the top of lift frame  102 , flange  104  may provide one or more attachment holes for lift hook  302  in various configurations. In one embodiment, a precise location of an attachment hole may cause lift device  100  to tilt, when lifted by the attachment hole, at a first angle roughly corresponding to a second angle given by an operational orientation of the work piece. The second angle may represent, for example, an orientation of cylinder  202  with respect to the engine in which cylinder  202  operates. In this manner, lift device  100  may provide for safer and expedited attachment of the work piece. Stand  110  may be coupled to lift frame  102  via pivot pin  124 , which may define an axis of rotation around which stand  110  may rotate fully (i.e., 360 degrees) with respect to lift frame  102 . Pivot pin  124  may penetrate a first bushing (obscured from view) contained within cylindrical end  130  of lift frame  102  and a second bushing (obscured from view) within cylindrical end  132  of stand  110 , along with head connector  106 . In certain embodiments, cylindrical ends  130 ,  132  are themselves bushings. Pivot pin  124  may be fixed with a pivot nut (obstructed from view in  FIG. 1 ) behind head connector  106 . Head connector  106  may be in the form of a plate having various holes, including holes for receiving pivot pin  124  and mounting bolts  120 , as will be described in further detail below. 
     Head connector  106  may further include locking holes  108  for receiving locking pin  122 , which may be used to mechanically secure stand  110  with respect to lift frame  102  by arresting rotation of stand  110  around pivot pin  124 . Locking pin  122  may be equipped with internal spring-loaded ball bearings (not visible in  FIG. 1 ) to facilitate entry and removal from locking holes  108 . Different instances of locking hole  108  may provide detention of stand  110  (and a work piece attached thereto) at desired angular positions in conjunction with locking pin  122  (see also  FIG. 3 ). 
     In  FIG. 1 , on each side of cylinder  202  and cylinder head  200  is water jumper  210  (of which only one instance is visible as shown) that forms a mounting surface. Water jumper  210  may include an opening to receive cooling water as well as threaded mounting holes, which may be used by lift device  100  to attach head connector  106  to cylinder head  200  using mounting bolts  120 . 
     In operation, lift device  100  may be positioned above cylinder head  200  using lift hook  302 . Lift device  100  may then be attached to cylinder head  200  at head connector  106  using mounting bolts  120 . Lift device  100 , as shown, may provide access to top portion  201  of cylinder head  200  for work piece removal operations, such as removal of mounting nuts  208 . Rotation of stand  110  may be arrested by inserting locking pin  122  into an appropriate one of locking holes  108 . After cylinder head  200  has been mechanically separated from cylinder  202 , lift device  100  may allow lift hook  302  to securely lift and transport cylinder head  200  to a desired location for service operations, as will be described below with respect to  FIGS. 2 and 3 . It is noted that the operations described above may be performed in a reverse order using lift device  100  when cylinder head  200  is mounted to cylinder  202 . 
     Turning now to  FIG. 2 , an image showing selected elements of an embodiment of novel lift device  100  is depicted. Lift device  100  is shown with removed cylinder head  200  being supported by lift hook  302  coupled to flange  104  of lift frame  102 . Visible in  FIG. 2  are both instances of head connector  106  (including respective locking holes  108 ), locking pin  122 , and pivot pin  124 , on respective sides of cylinder head  200 . Lift device  100  is attached to cylinder  200  via one instance of head connector  106  and two mounting bolts  120  on both sides of cylinder head  200 . In various embodiments (not shown), a different number and arrangement of mounting bolts  120  may be implemented. It is noted that, in the configuration shown, stand  110  forms a flat surface that is roughly parallel with seal surface  204 , of which an edge is visible in  FIG. 2 . 
     Advancing now to  FIG. 3 , an image showing selected elements of an embodiment of novel lift device  100  is depicted. Lift device  100  is shown with cylinder head  200  being made accessible as a work piece for service operations, for example, on seal surface  204 . Lift device  100  is shown in  FIG. 3  in a free-standing configuration, with stand  110  serving as a base for supporting lift frame  102  and cylinder head  200 . It is noted that, in  FIG. 3 , lift hook  302  (see  FIGS. 1 ,  2 ) is no longer attached to lift device  100 . Visible in  FIG. 3  is pivot nut  126  for bolting together lift frame  102 , stand  110 , and head connector  106  using pivot pin  124 . Locking pin  122 , shown protruding through head connector  106 , is used to fix stand  110  in an upright configuration, as shown. It is noted that no change in the attachment of cylinder head  200  to head connector  106  via mounting bolts  120  has taken place among the configurations of lift device  100  shown in  FIGS. 1 ,  2  and  3 . 
     It is further noted that, in various embodiments, stand  110  may be configured in different shapes and configurations, which may depend on a particular work piece for which lift device  100  is intended. As shown in the drawings, lift device  100  may be constructed using substantially straight members having a rectangular cross-section, for example, such as a square cross-section. In particular embodiments, the members with which lift device  100  is constructed may be hollow members of a suitable material, such as steel. The members may also be solid, when desired. The members with which lift device  100  is constructed may be round in cross-section and/or in shape (not shown in the drawings). The members with which lift device  100  is constructed may be selected by material and/or geometric form for a desired environment or operational condition. Certain portions of lift device  100  may be coated and/or painted for desired operational purposes and still perform the methods and operations described herein. 
     To the maximum extent allowed by law, the scope of the present disclosure is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited to the specific embodiments described in the foregoing detailed description.