Abstract:
An improved motor mount for attaching a drive motor to a clamshell lathe includes a gear box whose angular disposition can be adjusted relative to a drive gear housing affixed to the periphery of the clamshell lathe. This facilitates the positioning of the clamshell lathe on a workpiece with reduced chance of interference of the drive motor with neighboring obstructions.

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     This invention relates generally to portable metal finishing machines, and more particularly to split ring clamshell lathes of the type used to refurbish pipes, casings, engine shafts and the like in the field. 
     II. Discussion of the Prior Art 
     Split ring clamshell lathes of the type described herein are known in the art. U.S. Pat. Nos. 5,549,024, 4,739,685 and 4,939,964 to D. L. Ricci are illustrative of the technology involved. The split frame clamshell lathe generally comprises first and second semi-circular segments that are designed to be joined together so as to surround the pipe or shaft to be machined. The resulting annular assembly includes a stationary ring portion that becomes clamped to the workpiece and an abutting rotatable portion, including a ring gear, that is journaled to the stationary portion for rotation about the concentrically disposed workpiece. An air-operated, hydraulically-operated or an electrically-operated motor is operative coupled to the assembly and includes a drive gear designed to mesh with the ring gear on the rotatable segment of the clamshell lathe. Also mounted on the rotatable segment of the clamshell lathe is a tool block for supporting a cutting tool that can be made to advance in the radial direction against the pipe to be machined in incremental steps upon each revolution of the ring gear. 
     In these prior art arrangements, the drive motor mounts to the outside diameter of the stationary annulus and projects parallel to the longitudinal axis of the workpiece clamped within the central opening of the clamshell lathe. It frequently happens that in the field the pipe or shaft to be machined is in close proximity to neighboring structures which frequently make it difficult to place the clamshell lathe about the pipe or shaft to be turned. The motor, which typically projects approximately 18-20 inches either rearward or forward of the ring assembly, is a common source of difficulty in the desired placement of the clamshell lathe. Thus, a need exists for a motor mount fixture that will afford greater flexibility in the placement of a clamshell lathe. 
     The present invention affords a solution to the foregoing problem. In particular, it provides a motor mount that allows the motor to be selectively disposed at a plurality of different angular dispositions in a plane parallel to the plane of the clamshell lathe ring structures. As such, the motor position can be adjusted to avoid any nearby structures that might otherwise interfere with a desired placement of the clamshell lathe relative to the workpiece to be machined. This ease of set-up is especially important when working in environments where exposure to nuclear radiation must be kept to a minimum. 
     SUMMARY OF THE INVENTION 
     The foregoing objects, features and benefits of the invention are achieved by providing a motor mount for a clamshell lathe that comprises a drive gear housing that is adapted to be clamped or otherwise fixedly attached to the non-rotatable ring member of the clamshell lathe along with a gear box that is attachable to the drive gear housing at any one of a plurality of selectable angular positions. A first shaft is journaled for rotation in the drive gear housing and the gear box. This first shaft carries the pinion gear that mates with the clamshell&#39;s ring gear periphery, and a bevel gear is arranged to mesh with an input bevel gear that is journaled for rotation within the gear box. The input bevel gear, in turn, is adapted to be driven by one of an air motor, an electric motor or a hydraulic motor. 
     To provide a desired angular disposition of the drive motor relative to the clamshell lathe assembly, there is attached to the drive gear housing an annular bracket that is provided with a plurality of regularly, circumferentially-spaced threaded apertures extending through its thickness dimension for receiving the threaded ends of at least one bolt passing through and aperture(s) in the gear box housing. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a clamshell lathe having a prior art motor mount for coupling a drive motor to the lathe; 
     FIG. 2 is a perspective view of the preferred embodiment; and 
     FIG. 3 is an exploded perspective view illustrating the parts comprising the motor mount of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the device and associated parts thereof Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import. 
     To better understand the present invention, it is deemed helpful to first describe a typical prior art motor mount for a clamshell lathe. In this regard, reference is made to FIG. 3 of U.S. Pat. No. 5,549,024, the contents of which are hereby incorporated by reference as if fully set forth herein. Referring to the reference numerals used in the &#39;024 patent, there is bolted or otherwise affixed to the stationary annular member  32 , a mounting bracket  60 , including a radially extending arcuate shield member disposed in covering relation to a spur gear  56 , that meshes with the teeth of a ring gear  54 . The drive motor  58  is seen to project rearward from the mounting bracket  60  so as to extend parallel to the central axis of the clamshell annulus. As is mentioned in the introductory portion of this specification, the orientation of the motor  58  is fixed and because it may typically be approximately 20 inches in length, it may frequently interfere with placement of the clamshell lathe at a desired location along the length of the workpiece to be machined. 
     Referring next to FIG. 2, there is shown a perspective view of the improved clamshell lathe motor mount constructed in accordance with the present invention. The motor mount assembly is indicated generally by numeral  100  and comprises a drive gear housing member  102  having a planar base  104  with laterally extending flanges  106  projecting from opposed side edge surfaces thereof The flanges  106  are adapted to be engaged by clamping members (not shown) that are attached to the stationary ring of the clamshell lathe. The housing  102  has opposed parallel faces with a cylindrical cavity extending therebetween. The front face is covered by a cover plate  108  that attaches to the drive gear housing  102  by threaded screws. 
     Shown bolted to the opposite side surface of the drive gear housing is an annular bracket  110  and attached to it is a gear box  112 . The gear box  112  attaches to the annular bracket  110  by means of bolts (not shown) passing through apertures, as at  114  and  116 , formed in an arcuate flange portion  117  of the gear box and into threaded apertures in the annular bracket  110 . Secured to a planar face  118  of the gear box  112  is a motor adapter plate  120  to which a drive motor can be attached. 
     As will be explained further in greater detail with the aid of FIG. 3, the gear box can be rotated relative to the drive gear housing such that the motor, like that identified by numeral  58  in FIG. 1, will extend generally parallel to the plane of the ring members of the clamshell lathe and can be swung through 360° to orient the motor in any one of a plurality of angular dispositions. The manner in which this is accomplished will now be explained with the aid of the exploded view of FIG.  3 . 
     In FIG. 3, the drive gear housing  102  is seen to comprise an aluminum or steel block  122  having a cylindrical wall contoured to surround a cylindrical bore  124  that is dimensioned to contain a spur gear  126 . The gear  126  is keyed to the left end portion  128  of a drive shaft  130 . The shaft  130  is journaled for rotation by Timken bearings  132  and  134  that fit within an enlarged central bore  136  of the annular mounting bracket  110 . A suitable bushing  138  is also preferably used in combination with the Timken bearings to journal the left end of the shaft  130 . 
     The annular bracket  110  has a flange portion  140  with a plurality of regularly spaced apertures  142  extending therethrough. Without limitation, the apertures may be twelve in number and may be spaced at 30° intervals around the circumference of the flange. The bracket  110  is adapted to be bolted to the rear face  144  of the drive gear housing  102  by screws passing through screw holes or apertures  146  that extend through the thickness dimension of the annular mounting bracket  110 . 
     Keyed to the right end portion  148  of the shaft  130  is a miter gear  150 . The shaft  148  passes completely through the miter gear  150  and into needle roller bearings  152  which fit within an appropriately sized cylindrical cavity (not shown) in the gear box  112 . The miter gear  150  is adapted to mesh with a miter gear  154  that is journaled for rotation within a cylindrical bore  156  of the gear box. More specifically, a radial bearing  158  fits over a journal surface  162  of the miter gear  154  and a bushing  164  is disposed between the bearings  158  and the drive motor adapter plate  120  that bolts to the flat planar base  118  of the gear box. The miter gear  154  has a bore  166  centrally disposed therein and which is accessible through a bore  168  in the drive motor adapter plate  120 . As such, the drive shaft of a drive motor, like that shown in FIG. 1, can be inserted, along with a key, into the bore  166  to provide a driving force to the miter gear  154  and through the shaft  130  to the spur gear  126  to drive the rotatable member of the clamshell lathe. 
     To set the angular disposition of the drive motor, the bolts (not shown) that are made to pass through the bolt holes as at  114 ,  116 , in the gear box are removed. When the bolts are removed, the gear box can be rotated in 300 increments which is the spacing of the bolt holes  142  formed in the annular bracket  110  in the embodiment illustrated. With the motor projecting in a desired direction, the bolts are reinserted through the apertures  114 ,  116  and into the bolt holes  142  with which the apertures  114  and  116  are now aligned. 
     The ability to adjust the angular disposition of the gear box relative to the drive gear housing and the fact that the motor extends parallel to the plane of the clamshell lathe facilitates the mounting of the clamshell lathe on a workpiece without interfering with any surrounding structures that may be present. 
     This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself