Abstract:
A system, apparatus and method for alignment of a marine engine in a water vessel with either an existing or a design propeller shaft line of a propeller shaft of the vessel. The invention is also useful in positioning and aligning propeller shaft supports to the design shaft line before being secured to the hull of the vessel under construction. A laser gun for projecting a laser beam, a plurality of laser targets positionable into the propeller shaft support members, and a unique laser beam splitter temporarily connected to the engine output shaft cooperate to provide opposing colinear laser output beams viewably emitting from the laser beam splitter only when the marine engine is properly oriented coaxially of the engine crankshaft centerline with respect to the shaft line.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    Not applicable  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable  
         INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC  
         [0003]    Not applicable  
         BACKGROUND OF THE INVENTION  
         [0004]    1. Field of the Invention  
           [0005]    This invention relates generally to devices and methods for properly aligning the propeller shaft support members of a prop shaft connected in driving engagement with a marine engine in a water vessel under construction and for devices and methods associated with proper alignment of the engine mounted in the bed of a hull of a water vessel.  
           [0006]    2. Description of Related Art  
           [0007]    The use of lasers has become widespread in all aspects of measuring and construction due to the unique well-known features of laser beams. Small laser devices are almost exclusively routinely used in home and building construction for establishing both accurate distance measurements and accurate perpendicularity and parallel relationships between erected surfaces in construction.  
           [0008]    A number of prior art disclosures also teach the utilization of lasers to measure and effect establishing proper coaxial, parallel or orthogonal relationships between straight solid or hollow shaft members as follows:  
           [0009]    U.S. Pat. No. 6,342,946 to Holstein  
           [0010]    U.S. Pat. No. 4,698,491 to Lysen  
           [0011]    U.S. Pat. No. 6,476,914 to Hoelzl, et al.  
           [0012]    U.S. Pat. No. 6,337,742 to Lysen, et al.  
           [0013]    U.S. Pat. No. 6,434,849 to Hermann  
           [0014]    U.S. Pat. No. 5,194,920 to Mattila  
           [0015]    U.S. Pat. No. 6,515,294 to Busch et al.  
           [0016]    U.S. Pat. No. 5,026,998 to Holzl  
           [0017]    U.S. Pat. No. 6,040,903 to Lysen et al.  
           [0018]    U.S. Pat. No. 6,046,799 to Lysen  
           [0019]    U.S. Pat. No. 6,223,102 to Busch  
           [0020]    U.S. Pat. No. 5,430,539 to Lysen  
           [0021]    The Prüftechnik Dieter Busch AG company has developed a number of the above patents, one of which, U.S. Pat. 6,342,946, teaches determining the axial position of hollow cylinders through the utilization of a laser beam emitting device. As noted, this invention is suitable especially for measuring shaft tunnels of ships and for laying pipelines.  
           [0022]    The majority of the above prior U.S. Patents incorporate mirrors in splitting a beam into either perpendicular or parallel relationship one to another to establish a viewable alignment means with respect to the shaft or tunnel of interest. However, none of the prior teaching appears to disclose the utilization of a laser to project a beam along the design shaft line of a boat during construction or projecting a laser beam accurately colinearly along the same shaft line of an existing vessel and to strike a unique laser beam splitting apparatus which, when attached to the output shaft of the marine engine, will provide very accurate visual data or information as to whether the engine is properly aligned in all degrees of freedom with respect to the hull and the laser beam.  
         BRIEF SUMMARY OF THE INVENTION  
         [0023]    This invention is directed to a system, apparatus and method for alignment of a marine engine in a water vessel with either an existing or a design propeller shaft line of a propeller shaft of the vessel. The invention is also useful in positioning and aligning propeller shaft supports to the design shaft line before being secured to the hull of the vessel under construction. A laser gun for projecting a laser beam, a plurality of laser targets positionable into the propeller shaft support members, and a unique laser beam splitter temporarily connected to the engine output shaft cooperate to provide opposing colinear laser output beams viewably emitting from the laser beam splitter only when the marine engine is properly oriented coaxially of the engine crankshaft centerline with respect to the shaft line.  
           [0024]    It is therefore an object of this invention to provide an apparatus for attachment to the output shaft of a marine engine in a water vessel for use in combination with a laser beam projected colinearly along the shaft line of the propeller shaft for accurate and proper engine alignment thereby.  
           [0025]    Still another object of this invention is to provide a system including a laser and a laser beam splitter apparatus for use in accurately aligning engines within an existing or under construction marine vessel.  
           [0026]    Yet another object of this invention is to provide a method for the accurate positioning and attachment of prop shaft support hardware to be colinear with the design shaft line and the engine propeller shaft of the water vessel under construction.  
           [0027]    Another object of this invention is to provide a unique laser beam splitter which produces oppositely extending output laser beams precisely orthogonally to an input laser beam striking the input face of the device.  
           [0028]    Yet another object of this invention is to provide a method of properly aligning a marine engine within a water vessel utilizing a laser and a laser beam splitting apparatus attached to the output shaft of the engine after the propeller shaft has been removed.  
           [0029]    In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
       [0030]    [0030]FIG. 1 is a schematic side elevation view of the rear portion of a marine vessel under construction.  
         [0031]    [0031]FIG. 2 is a view similar to FIG. 1 showing a laser and laser beam emitted therefrom with respect to the positioning and attachment of the propeller shaft support members.  
         [0032]    [0032]FIG. 3 is a view similar to that of FIG. 2 depicting the utilization of a laser beam splitter to insure proper marine engine alignment within the hull of the water vessel and with respect to the already in place propeller shaft support members.  
         [0033]    [0033]FIG. 4 is an enlargement of a portion of FIG. 3 showing the rear portion of the engine.  
         [0034]    [0034]FIG. 5 is a further enlarged view of a rear portion of the engine in FIG. 4 showing the laser beam splitter schematically.  
         [0035]    [0035]FIG. 6 is a front elevation view of the laser beam splitter.  
         [0036]    [0036]FIG. 7 is a side elevation section view of FIG. 6.  
         [0037]    [0037]FIG. 8 is a front elevation view of the laser target attached to the laser beam splitter shown in FIGS. 6 and 7.  
         [0038]    [0038]FIG. 9 is an enlarged side view of the laser beam splitter useful generally absent the support housing.  
         [0039]    [0039]FIG. 10 is a cross section view of a typical propeller shaft support target and support bearing member therefor as shown in front elevation view in FIG. 11. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
     New Installations  
       [0040]    Referring to FIGS. 1 and 2, during a new hull H construction of a water vessel, after all stringers and structural bulkheads, including forward and aft engine room bulkheads B 1  and B 2 , respectively, are installed and complete, the present invention in one aspect thereof may be utilized to establish proper alignment of engine and driveline supports C and D. The hull H should be level to within ¼″ port to starboard and fore and aft. Pick a station ST 1  forward of the engine room and one ST 2  in the engine room. Using a plumb bob, drop the forward station ST 1  location to the floor at  46  using a piece of tape to mark this. This will provide a distance  20  from the forward station ST 1  to the transom centerline T/L at  44  at the design water line (DWL). Measure rearward along each side of the hull this dimension  20  and place a mark on a piece of tape. Hold and snap a chalk line transversely between the marks on the transom T. A plumb bob dropped from  44 , the transom centerline at DWL, will fall on this mark providing a parallel line to the transom T. From the design drawings, project the shaft line S/L rearward past the transom T. Draw a line from DWL at the transom centerline to the projected shaft line a distance  36 . This intersection with shaft line S/L will establish the location for the first laser target  12 .  
         [0041]    To insure that the bulkhead B 1  is per the design drawing, measure from station S 3  in the engine room to the rearward bulkhead B 1  and verify this distance  18  to coincide with the design drawing by subtracting the design distance  18  from design distance  32 . Station S 2  may also be used in this same manner by subtracting distance  34  from distance  18  and then subtracting that distance from  32 . If the boat is a single screw type, this establishes the shaft line S/L location. If the vessel is a twin screw, measurement from centerline to the buttocks line at ST 5  noted in the design drawings will be required.  
         [0042]    Referring to FIG. 2, to set the first target  12 , as shown in FIG. 8 described below, a 4″×2″ aluminum box tube  20  as long as the hull is wide is mounted on tripods J and centered port and starboard on the transom and plumbed to the chalk line using three plumb checks. Measure down from DWL using the dimension  36  from the drawing showing the transom shaft line S/L intersection. Line this up to the center of the leveled aluminum tube  20 . The tripods J are used to move the tube  20  up or down to find and establish tube  20  to be level.  
         [0043]    Drill a ⅛″ hole in the center of the tube  20  using centerline for single screw or the spaced apart buttocks dimension off centerline for twin screw installations. Set the distance  36  from the hole to DWL using the projected shaft line S/L intersection dimension. Use a 1″ hole saw to open the ⅛″ forward hole in the aluminum to prevent interference with a laser beam. Mount and align target  12  to S/L and attach to the tube  20 . Mount the forward engine room bulkhead B 1  target  14  and project the laser beam between the two points. This establishes the shaft line S/L. The laser  22 , atop tripod K, properly aligned to project a laser beam L to establish the shaft line S/L is now set to project the laser light beam L along the shaft line S/L and will not need to be moved during the rest of the strut and shaft log installation.  
         [0044]    With targets  24 ,  26 ,  28  and  30 , as shown typically in FIGS. 10 and 11, sized to fit into the ends of the strut C and shaft log D move them with the respective targets in place as shown to adjust each of these struts C and shaft log D until the laser beam L passes through the target holes in each target  24 ,  26 ,  28  and  30  and are also spaced apart the design distances  38  and  40 .  
       Aligning Marine Engine(s)  
       [0045]    Referring now to FIG. 3, to confirm proper alignment or to realign an engine E already mounted into the hull H of an existing vessel or one under construction as shown in FIGS. 1 and 2, the prop shaft(s) (not shown) are first removed and then targets  24 ,  26 ,  28  and  30  are installed into each end of the strut C and shaft log D, respectively, as shown and as previously described. A beam splitter/housing assembly or apparatus is shown generally at numeral  50  and is temporarily rigidly connected to the output flange F of the transmission of the engine E using existing threaded mounting members.  
         [0046]    When the laser  22  is properly supported and adjusted on tripod K, the laser beam L passes through each of the targets  24 ,  26 ,  28  and  30  in place. As also seen in FIGS. 4 and 5, the laser beam L must properly strike the center of the laser beam splitter  50  as will be described in detail herebelow to provide viewable indicia in the form of output beams La and Lb which will only be emitted from apertures  56  and  58  when the engine is precisely aligned so that the centerline of the engine E and its output flange F are colinear with laser beam L. To accomplish proper engine E alignment utilizing the laser splitter  50 , the engine supports M and N are adjusted to reposition the engine E as required in the pitch mode, the yaw mode and vertically and horizontally as aided by the information obtained from the laser beam splitter adapter  50 . Again, only when proper alignment is achieved will the output beams La and Lb be seen to emit from apertures  56  and  58 .  
       Laser Beam Splitter  
       [0047]    Referring now to FIGS.  4  to  9 , the adapter  50  and method of the present invention uses a polarizing beam splitter  70  combined with a birefringent retarder  80  and mirror  82  to convert the input laser beam L from the laser  22  into two counter-propagating beams La and Lb orthogonal to the input beam L. The laser beam splitter  70  and birefringent retarder  80  and mirror  82  are rigidly attached together by glue and are securely positioned centrally on plate  54 . The housing also includes an annular ring  52  as best seen in cross section in FIG. 7 and as described herebelow. A plano-convex objective lens  72  mounted on the input face  84  of the beam splitter  70  brings the two output beams La and Lb to a well-defined focus. A 150 mm focal length lens cemented in place against the input surface  84  is preferred.  
         [0048]    The beam splitter  70  has a cube shape formed of two mating glued together prisms  74  and  76  with an optical coating on one of the internal prism surfaces  74   a  or  76   a  to define a partially reflective hypotenuse surface  78 . The hypotenuse surface  78  is coated with an antireflection (AR) dielectric coating which transmits light with a P-polarization while reflecting the portion of light with an S-polarization. When the linearly polarized beam L is directed into the beam splitter  70  through a central aperture  68  of target  64  and lens  72  at an angle of polarization of  450  with respect to the input face  84 , approximately 50% of the light will transmit directly through the cube  70  as Lc in FIG. 9. The remaining light will be reflected at 90° at La. The reflected beam La composes one of the two output beams of the beam splitter  70 .  
         [0049]    Birefringence  
         [0050]    Birefringence generally refers to the unique capability of a material or device to exhibit two indexes of refraction, one index for the two directions that are the same and the other for the direction along which the molecular structure is spaced differently. Crystalline materials may have different indexes of refraction associated with different crystallographic directions which produces the birefringence feature. Birefringent materials or members are used widely in optics to produce polarizing prisms and retarder plates such as a quarter-wave plate. Putting such a birefringent material between crossed polarizers can give rise to interference colors. Examples of birefringent materials which exhibit two indexes of refraction are:  
         [0051]    Tourmaline  
         [0052]    Calcite  
         [0053]    Quartz  
         [0054]    Sodium Nitrate  
         [0055]    Ice  
         [0056]    Rutile (TiO 2)  
         [0057]    A phase retarder  80  (birefringent waveplate) with a retardance of one-quarter wave at the operating wavelength is mounted by gluing against one side of the cube  70  where the transmitted beam Lc would otherwise exit from the mounting face  86 . This waveplate  80  is oriented so that the fast axis is rotated 45° with respect to the angle of polarization of the output beam. In this configuration, the linearly polarized transmitted beam portion Lc is converted to a circularly polarized beam which is either left or right handed orientation depending on the orientation of the waveplate  80 —the device will work either way. A zero-order 532 mm quarter waveplate is preferred which is cemented to the output face  86 .  
         [0058]    A 100% reflecting mirror  82  is mounted by cementing against the waveplate  80  so that the circularly polarized beam strikes mirrored surface  88  at normal incidence. The reflected beam Ld experiences a 180° phase shift off this mirror and returns along the same path of propagation as it arrived. When this beam travels back through the waveplate  80 , it undergoes another quarter wave phase shift converting the circularly polarized beam back to a linearly polarized beam Ld; however, now the polarization is rotated 90°. This, in effect, converts the p-polarized beam to an s-polarized beam Ld. A broadband dielectric mirror cemented to the phase retarder  80  was used in prototype construction; however, production units will utilize an HR reflective coating cemented to surface  87  of the phase retarder  80 .  
         [0059]    When the return beam Ld reaches the beam splitter hypotenuse  78 , the direction of propagation is reflected 90° in a direction directly opposite from the first reflected beam La. Since one of the prism hypotenuses  74   a  or  76   a  is AR coated, the second output beam Lb reflects off the same surface  78  as the first, insuring that the two output beams La and Lb are both co-aligned and counter propagating. To establish this condition, it is necessary that the beam cube entrance and exit faces or surfaces  84  and  86  are parallel and that the waveplate  80  and mirror  82  surfaces are normal to the transmitted beam Lc. This is handled through maintaining tight fabrication and alignment tolerances on all the optical surfaces.  
         [0060]    Referring particularly to FIGS. 5, 6 and  7 , the laser beam L strikes the objective lens  72  only when the laser beam is aligned properly to fully pass through the laser splitter target aperture  68 . This insures a generally accurate normal or orthogonal relationship between the laser beam L and the input face  84  of the laser beam splitter  70 . As described hereinabove, the laser beam L is split into two output beams La and Lb. These output beams La and Lb are oriented precisely orthogonally with respect to all faces of the beam splitter  70 . Moreover, the exit apertures  56  and  58  formed into the flange  52  are also precision aligned to be orthogonally oriented in both the plan and side elevation views shown in FIGS. 6 and 7. It has been found that a focus length of approximately 5.3″ between the centerline of the housing  51  and apertures  56  and  58  is preferred.  
         [0061]    Referring now to FIGS. 10 and 11, a typical propeller shaft support target is shown generally at  24  and is similar to targets  26 ,  28  and  30  in FIGS. 1 through 3 including a rigid cylindrical bushing or bearing  96  sized in diameter to snugly slide into the end of one of the propeller shaft support members C or D as previously described in FIGS.  1  to  3 . This housing  24  also includes an enlarged flange  98  to provide a stop or shoulder and a squareness indicator to insure that the bearing surface  96  is properly aligned and not cocked within the cylindrical end surface of the corresponding propeller shaft support C or D.  
         [0062]    The propeller shaft support target  90  includes a series of concentric viewable rings and a central aperture  92  formed therethrough. The aperture  92  is sized to just allow the laser beam L projected from the laser  12  as previously described so as to provide viewable indicia on the target surface immediately adjacent to the aperture  92  as to when the laser beam L is not properly aligned and passing directly through the aperture  92 . A thumb cavity  94  facilitates easy removal of the target  90  when not in use. Importantly, the concentricity between the cylindrical surface  96  and the laser aperture  92  must be maintained to insure the highest degree of accuracy from the utilization of the present system and methodology for propeller shaft and engine alignment.  
         [0063]    While the instant invention has been shown and described herein in what are conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein, but is to be afforded the full scope of the claims so as to embrace any and all equivalent apparatus and articles.