Abstract:
A propeller straightening apparatus utilizes a pair of adjustable hydraulic cylinders to apply pressure to a selected propeller blade of the propeller. Adjustments can include lateral, longitudinal and tilt angle. A propeller mount holds the propeller in a fixed position during straightening. The mount can be quickly loosened so that the propeller can be rotated to present a different propeller blade to the hydraulic cylinders. The cylinders have polyurethane tips portions that help grip the surface of the propeller. The apparatus can bend a selected propeller blade to change rake and/or pitch.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Priority of U.S. Provisional Patent Application Ser. No. 60/502,999, filed Sep. 15, 2003, incorporated herein by reference, is hereby claimed. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable 
   REFERENCE TO A “MICROFICHE APPENDIX” 
   Not applicable 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a method and apparatus for straightening a bladed propeller that employs a pair of independently adjustable blade bending units, each preferably a hydraulically operated cylinder and pushrod device that enable pressure to be applied to a pair of spaced apart positions on a propeller, enabling either pitch and/or rake adjustments to be made to the propeller by simultaneously extending the spaced apart pushrods as they engage a selected one of the propeller blades. 
   2. General Background of the Invention 
   For many years, propellers have been manually straightened using a very large hammer with a plastic, polymeric or rubber head. Such hammers are commercially available from McDurmon Distributing of Fenton, Mich. Another example of such a hammer is sold by Garland Hammers (Garland Manufacturing Company) of Saco, Me. 
   Such a manual bending of a propeller in order to straighten it is both time consuming and imprecise. The present provides an improved method and apparatus for straightening propellers that enables precise bending of the propeller blades to achieve a desired change in rake and/or pitch. 
   Some propeller straightening devices have been patented. The following table lists examples of propeller repair patents. 
   
     
       
             
             
             
             
           
         
             
                 
               TABLE 
             
             
                 
                 
             
             
                 
               Pat. No. 
               Title 
               Issue Date 
             
             
                 
                 
             
           
           
             
                 
               2,013,705 
               Process for Shaping Helical 
               Sep. 10, 1935 
             
             
                 
                 
               Bodies and Means for Carrying 
             
             
                 
                 
               out Said Process 
             
             
                 
               2,393,317 
               Straightening Press for 
               Jan. 22, 1946 
             
             
                 
                 
               Aircraft Propellers and 
             
             
                 
                 
               the Like 
             
             
                 
               3,032,092 
               Propeller Straightening 
               May 1, 1962 
             
             
                 
                 
               Apparatus 
             
             
                 
               4,058,880 
               Propeller Making Apparatus 
               Nov. 22, 1977 
             
             
                 
                 
               and Method 
             
             
                 
               4,222,259 
               Propeller Reconditioner 
               Sep. 17, 1980 
             
             
                 
               5,315,856 
               Apparatus for Propeller 
               May 31, 1994 
             
             
                 
                 
               Straightening 
             
             
                 
               5,377,521 
               Method for Propeller 
               Jan. 3, 1995 
             
             
                 
                 
               Straightening 
             
             
                 
               5,713,233 
               Vane Adjustment Machine 
               Feb. 3, 1998 
             
             
                 
                 
             
           
        
       
     
   
   BRIEF SUMMARY OF THE INVENTION 
   The present invention provides an apparatus for straightening a dented or bent or otherwise mis-shapen propeller. The apparatus includes a frame that has an upper section and a lower section. The upper section can tilt upon the lower section. 
   There are a pair of hydraulic rams carried by the frame. 
   A hydraulic power unit can be provided to operate the rams. A propeller mount is supported upon the frame for holding the propeller to be straightened. 
   A plurality of adjustment mechanisms are provided for moving each ram independently of the other, the adjustment mechanisms including at least one lateral adjuster at least one longitudinal adjuster, and a tilt adjustment that tilts the upper section into a desired inclined position relative to the lower section. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein: 
       FIG. 1  is an elevation view of the preferred embodiment of the apparatus of the present invention; 
       FIG. 2  is another elevation view of the preferred embodiment of the apparatus of the present invention; 
       FIG. 3  is an end view of the preferred embodiment of the apparatus of the present invention; 
       FIG. 4  is a partial elevation, partial sectional view of the preferred embodiment of the apparatus of the present invention; 
       FIGS. 5A–5B  are partial sectional, elevation views of the preferred embodiment of the apparatus of the present invention illustrating the propeller holder; 
       FIGS. 6A ,  6 B,  6 C are partial perspective views of the preferred embodiment of the apparatus of the present invention illustrating the straightening of a mis-shapen propeller blade; 
       FIG. 7  is a fragmentary view of the preferred embodiment of the apparatus of the present invention; 
       FIG. 8  is a partial perspective view of the preferred embodiment of the apparatus of the present invention; and 
       FIG. 9  is partial perspective top view taken of the preferred embodiment of the apparatus of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1–3  show generally the preferred embodiment of the apparatus of the present invention designated jointly by the numeral  5 . Propeller blade repairing apparatus  5  has a base  6  that is fixed, supported by an underlying floor  14  such as a concrete shop floor  14  with a plurality of feet  7  that can be adjustable with respect to the base. In this fashion, the feet  7  can be used to level the base  6 . 
   Base  6  supports a moving frame  8  that can be tilted to a selected angle. Moving frame  8  can be mounted upon arc shape tracks  10  that are provided on base  6 . A plurality of rollers  11  can engage each track  10  and thus be used to interface between moving frame  8  and base  6 . 
   Hydraulic power unit  9  (see  FIG. 14 ) is commercially available and can be a “V-Pak” manufactured by Parker Hannifin Corporation, Parker Hydraulics Group (www.parker.com). Such a power unit  9  is self-contained, and typically includes a hydraulic pump, electric motor, valving, and a pressure control. 
   Moving frame  8  can include a pair of side panels  12  and  13  connected by a plurality of transverse beams  17 . Moving frame  8  supports an upper hydraulic cylinder  18  and a lower hydraulic cylinder  19 . Each hydraulic cylinder  18 ,  19  has a pushrod that can be used to straighten or otherwise repair the individual damaged blades  22  mounted upon hub  21  of propeller  20  (see  FIGS. 6A ,  6 B,  6 C). Upper hydraulic cylinder  18  has upper pushrod  23 . Lower hydraulic cylinder  19  has lower pushrod  24 . Each pushrod  23 ,  24  can be provided with a cushioned (e.g. polymeric) end portion  25 . End portion  25  can be removable from its pushrod  23  or  24  for easy servicing or replacement. Arrows  16  in  FIG. 3  schematically illustrate extension/retraction of pushrods  23 ,  24 . 
   The apparatus  5  of the present invention can be adjusted to change the position of each pushrod  23 ,  24  (laterally, longitudinally and/or the angle of inclination) relative to a bent or damaged propeller blade  22  that is to be repaired or straightened. Upper cylinder lateral adjustment wheel  26  can be used to move the upper hydraulic cylinder  18  laterally with respect to propeller  20 . Similarly, lower cylinder lateral adjustment wheel  27  can be used to move the lower hydraulic cylinder  19  in a lateral direction with respect to propeller  20 . Basically, each of the upper and lower hydraulic cylinders  18 ,  19  can be moved to any position in between side panels  12 ,  13  of moving frame  8 . 
   Each hydraulic cylinder  18  can be adjusted longitudinally with respect to propeller  20 . Upper cylinder longitudinal adjustment wheel  28  can be used to move the upper hydraulic cylinder  18  in a fore and aft direction with respect to base  11 . Similarly, lower cylinder longitudinal adjustment wheel  29  can be used to move the lower hydraulic cylinder  19  in a fore and aft direction. The longitudinal adjustment wheels  28 ,  29  can be used to move the hydraulic cylinders  18 ,  19  toward or away from hydraulic power unit  9 . 
   Another adjustment provided with the apparatus  10  of the present invention is a tilt adjustment. This tilt adjustment is preferably in the form of an extensible hydraulic cylinder/pushrod  30 . By extending or retracting cylinder  30 , the upper, moving frame  8  tilts relative to base  6  as indicated by arrow  15  in  FIGS. 1 and 2 . Alternatively, a turnbuckle can be used that can be used to manually adjust the tilted position of frame  8 . 
   The lateral adjustment wheels  26 ,  27  move the selected hydraulic cylinder  18  or  19  laterally by rotating a threaded shaft  31  that engages nut  32  attached to a cylinder mount  33 . Each cylinder mount  33  has brass wear plates that attach to a transverse beam  35 . Each cylinder mount  33  can travel side to side as indicated by arrows  61  and responsive to rotation of shaft  31  (curved arrow  62 ) as seen in  FIG. 9 . Beams  35  span between side panels  12 ,  13  of moving frame  8 , connecting to longitudinal bearings  34  (see  FIG. 9 ). Bearings  34  travel upon rails  64  at the upper end of side panels  12 ,  13 . 
   For longitudinal adjustment, wheel operated chains are provided as shown in  FIGS. 1 ,  3 ,  4  and  9 . For the upper hydraulic cylinder  18  (see  FIGS. 4 ,  7  and  9 ), upper cylinder longitudinal adjustment wheel  28  has a sprocket  63  engaging chain  36 . Wheel  28  can be rotated to move endless chain  36  that engages sprockets  37 ,  63 . Sprocket  37  rotates shaft  38 . 
   Rotation of shaft  38  simultaneously rotates shaft  39  and sprocket  40  using chain  44 . Chain  41  engages sprocket  40  and also connects to a upper hydraulic cylinder mount  33  at beams  34 . Chain  41  engages sprocket  42  that is at the front end of the machine next to the v-pak hydraulic power unit  9  as shown in  FIG. 2 . Sprocket  42  is rotated by chain  41  and upper cylinder longitudinal adjustment wheel  28 . Sprocket  42  rotates shaft  43 . Endless chain  44  engages sprockets  37  and  40 . Rotation of sprocket  48  rotates sprocket  42  and shaft  43 . Endless chain  43  spans between sprocket  40  and sprocket  42 . 
   Shaft  39  is attached to and rotates with sprockets  40  and  45 . A similar if not identical adjustment mechanism can be used for transverse longitudinal adjustment of the lower hydraulic cylinder  19  as was shown and described for the upper hydraulic cylinder  18 . 
     FIGS. 5A ,  5 B show the propeller support portion of the apparatus  5  of the present invention. The propeller support  56  provides a shaft  58  having tapered section  58 A and generally cylindrically shaped section  58 B. Rod  68  extends between cylindrically shaped section  58  and linkage  59 . The propeller  20  can be mounted to section  58 A (e.g. bolted) as shown in  FIGS. 5A ,  5 B. Hydraulic cylinder  57  can be actuated using a hydraulic control valve. Typically, the shaft  58  is spring loaded with spring  60  to assume an upper, free spin position that enables rotation of shaft  58  and propeller  20  so that a selected blade can be positioned for repair and/or straightening. A rotary connection can be provided at the connection of rod  68  to linkage  59 . If a user wants to lock the propeller, the cylinder  57  is actuated so that pushrod  51  pulls the shaft  58  downwardly (arrow  53 ) using linkage  59  and overcoming spring pressure. This action bottoms the cylindrically shaped section  58 B against bottom plate  66  of shaft support  65  so that the shaft  58  and thus propeller  20  will not rotate. The propeller  20  is thus positioned for repair and/or straightening. Propeller  20  can be removed from support  56  by removing nut  54  and washer  53  from shaft  58  threaded end portion  58 . 
   Parts List 
   The following is a list of suitable parts and materials for the various elements of the preferred embodiment of the present invention. 
   
     
       
             
             
           
             
             
           
         
             
                 
             
             
               Part Number 
               Description 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               5 
               propeller blade repair apparatus 
             
             
               6 
               base 
             
             
               7 
               feet 
             
             
               8 
               moving frame 
             
             
               9 
               hydraulic power unit 
             
             
               10 
               track 
             
             
               11 
               roller 
             
             
               12 
               side panel 
             
             
               13 
               side panel 
             
             
               14 
               floor 
             
             
               15 
               arrow 
             
             
               16 
               arrow 
             
             
               17 
               transverse beam 
             
             
               18 
               upper hydraulic cylinder 
             
             
               19 
               lower hydraulic cylinder 
             
             
               20 
               propeller 
             
             
               21 
               hub 
             
             
               22 
               blade 
             
             
               23 
               upper pushrod 
             
             
               24 
               lower pushrod 
             
             
               25 
               cushioned end portion 
             
             
               26 
               upper cylinder lateral adjustment 
             
             
                 
               wheel 
             
             
               27 
               lower cylinder lateral adjustment 
             
             
                 
               wheel 
             
             
               28 
               upper cylinder longitudinal 
             
             
                 
               adjustment wheel 
             
             
               29 
               lower cylinder longitudinal 
             
             
                 
               adjustment wheel 
             
             
               30 
               tilt adjustment rod 
             
             
               31 
               threaded shaft 
             
             
               32 
               nut 
             
             
               33 
               cylinder mount 
             
             
               34 
               bearing 
             
             
               35 
               transverse beam 
             
             
               36 
               endless chain 
             
             
               37 
               sprocket 
             
             
               38 
               shaft 
             
             
               39 
               shaft 
             
             
               40 
               sprocket 
             
             
               41 
               chain 
             
             
               42 
               sprocket 
             
             
               43 
               shaft 
             
             
               44 
               endless chain 
             
             
               45 
               sprocket 
             
             
               46 
               shaft 
             
             
               47 
               endless chain 
             
             
               48 
               sprocket 
             
             
               49 
               table 
             
             
               50 
               surface 
             
             
               51 
               pushrod 
             
             
               52 
               arrow 
             
             
               53 
               washer 
             
             
               54 
               nut 
             
             
               55 
               threaded end portion 
             
             
               56 
               propeller support 
             
             
               57 
               hydraulic cylinder 
             
             
               58 
               tapered shaft 
             
             
               58A 
               tapered section 
             
             
               58B 
               cylindrical section 
             
             
               59 
               linkage 
             
             
               60 
               spring 
             
             
               61 
               arrow 
             
             
               62 
               curved arrow 
             
             
               63 
               sprocket 
             
             
               64 
               rail 
             
             
               65 
               shaft support 
             
             
               66 
               bottom plate 
             
             
               67 
               side wall 
             
             
               68 
               rod 
             
             
                 
             
           
        
       
     
   
   The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.