Patent Abstract:
A belt grinding finishing tool incorporates a pair of mounting arms projecting forwardly from a drive housing to support a single abrasive belt entrained around drive and idler pulleys. The first mounting arm is positionally fixed relative to the drive housing, but the second mounting arm is pivotally mounted to permit relative pivotal movement thereof. The dual mounting arm configuration enables a tubular member to be placed between the mounting arms to effect a finishing of opposing sides of the outer surface of the tubular member simultaneously. A support housing detachably mounted on the drive housing includes a support handle that can be selectively connected to alternative attachments mounts formed on the support housing. An actuation lever extending outwardly from the second mounting arm permits the operator to cause pivotal movement of the pivoted second mounting arm to accept the tubular member to be finished between the mounting arms.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims domestic priority on U.S. Provisional Patent Application Ser. No. 60/676,084, filed Apr. 29, 2005, the contents of which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to a hand tool for finishing tubing materials and, more particularly, to a manually manipulated belt grinder or abrading tool that is operable to finish opposing sides of a tubing member simultaneously. 
   Manually manipulated miniature belt grinders are used within small cavities or restricted openings in sheet metal, castings, forgings and the like for deburring and finishing operations. The miniature belt grinders are typically constructed with an endless belt having an outer abrasive surface trained about a drive pulley and a contact pulley. The endless belt corresponds to an outwardly extending arm so that the metallic material to be finished can be engaged with either side of the abrasive belt. A pneumatic motor typically provides the operative power for rotating the abrasive belt so that the tool can be driven through manipulation of a hand control while the rotated belt is pressed against the metallic surface to be finished. Conventionally, the pneumatic motors used to drive the belt grinders are suitably fixed to the casing of the grinder such that they provide a convenient grinder manipulating handle with the drive shaft thereof extending into the casing and serving to support and effect driven rotating of the drive pulley about which one end of the abrasive belt is entrained. 
   One such miniature belt grinding tool can be found in U.S. Pat. No. 4,368,597, issued to Elwin H. Fleckenstein, et al on Jan. 18, 1983, and in U.S. Pat. No. 4,411,106, issued to Elwin H. Fleckenstein on Oct. 25, 1983. The Fleckenstein grinding tool is pneumatically driven and is formed with a single arm on which is mounted a drive pulley and a tensioning idler pulley with the abrasive belt being entrained around the pulleys to be engagable with the metallic surface to effect a finishing thereof. Similar tools are taught in U.S. Pat. No. 4,754,579, issued to Dennis M. Batt on Jul. 5, 1988, in which a dust collection apparatus is associated with the rotating abrasive belt to minimize the dispersal of dust during the operation of the portable hand-held implement. Such grinding devices are also constructed in a configuration that is adapted for attachment to a rotary power tool, as is shown in U.S. Pat. No. 4,858,390, issued to Nisan Kenig on Aug. 22, 1989, and in U.S. Pat. No. 5,031,362, issued to Reinhold Reiling on Jul. 16, 1991. As with the pneumatically power miniature grinding tools, the abrasive belt is entrained around drive and tensioning pulleys mounted on a single outwardly extending arm. 
   The abrasive belt can also be mounted in a triangular configuration to facilitate utilization thereof against a cylindrical tubing member by entraining the abrasive belt around three pulleys, one drive pulley and a pair of spaced apart idler pulleys between which the tubular object to be finished can be positioned so that the abrasive belt can form around the cylindrical surface of the tubing member for enhanced engagement thereof. As is depicted in U.S. Pat. No. 3,566,549, issued to James A. Britton on Mar. 2, 1971, and in U.S. Pat. No. 5,628,678, issued to Frank Tridico on May 13, 1997, the second idler pulley can be mounted on a second mounting arm that is spring-loaded away from the main housing of the tool. When the abrasive belt is placed into engagement with a tubular member to effect a finishing operation thereon, the second arm yields against the biasing apparatus to permit the abrasive belt to partially wrap around the surface of the tubing member. While up to about half of the cylindrical surface of the tubing member can be finished, the tool would have to be oriented in an opposing direction in order to finish the opposing half of the tubing member. 
   Accordingly, it would be desirable to provide a hand grinder apparatus that would be operable to finish opposing sides of a tubing member simultaneously so that the finishing operation for a tubing member can be accomplished more quickly than with the belt grinder devices known in the art. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to overcome the disadvantages of the prior art by providing a double-armed finishing tool for smoothing opposing sides of a tubular member simultaneously. 
   It is a feature of this invention that the finishing tool is a belt grinding apparatus having a pair of outwardly extending mounting arms about which an abrasive belt is entrained to provide an abrading surface engagable with opposing sides of a tubular member placed between the mounting arms. 
   It is an advantage of this invention that the tubular member can be finished quickly by smoothing opposing sides thereof simultaneously. 
   It is another object of this invention to provide a belt grinding finishing apparatus that is operable to smooth opposing sides of a tubular member simultaneously. 
   It is another feature of this invention that one of the mounting arms is pivotally supported on the drive housing for movement about a pivot pulley relative to the other mounting arm. 
   It is another advantage of this invention that the pivoted mounting arm can be positioned to allow a tubular member to be positioned between the mounting arms. 
   It is yet another feature of this invention that an actuation lever projects outwardly from the second mounting arm to permit the grasping of the actuation lever for opening the gap between the distal tips of the mounting arms. 
   It is still another feature of this invention that the first mounting arm incorporates a belt tensioning mechanism that biases the idler pulley at the distal tip of the first mounting arm away from the drive pulley. 
   It is still another advantage of this invention that the belt tensioning mechanism allows the second mounting arm to be pivoted away from the first mounting arm by drawing the idler pulley on the first mounting arm toward the drive pulley. 
   It is yet another advantage of this invention that the belt tensioning mechanism is operable to pivot the second mounting arm toward the first mounting arm, minimizing the distance between the respective distal tips of the mounting arms. 
   It is yet another feature of this invention that the second mounting is operably associated with a stop member to limit the pivotal movement of the second mounting arm toward the first mounting arm to prevent interference therebetween. 
   It is a still another object of this invention to provide a drive housing for a belt grinding tool in which a single abrasive belt can be entrained between a pair of mounting arms so that opposing sides of a tubular member can be finished simultaneously with the same abrasive belt. 
   It is a further feature of this invention that a pair of fixed pulleys rotatably mounted on the drive housing enables the entrainment of a single abrasive belt to be operable simultaneously along a pair of mounting arms. 
   It is still a further feature of this invention that a support housing detachably mounted on the drive housing has a support handle connected thereto to facilitate the positioning of the finishing tool. 
   It is a further advantage of this invention that the support handle is selectively connected to alternate attachment mounts to provide selectively alternative positioning of the support handle. 
   It is yet another object of this invention to provide a double-armed belt grinding tool for use in finishing structural members in which the grinding tool is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use. 
   These and other objects, features and advantages are accomplished according to the instant invention by providing a belt grinding tool incorporating a pair of mounting arms projecting forwardly from a drive housing to support a single abrasive belt entrained around drive and idler pulleys. The first mounting arm is positionally fixed relative to the drive housing, but the second mounting arm is pivotally mounted to permit relative pivotal movement thereof. The dual mounting arm configuration enables a tubular member to be placed between the mounting arms to effect a finishing of opposing sides of the outer surface of the tubular member simultaneously. A support housing detachably mounted on the drive housing includes a support handle that can be selectively connected to alternative attachments mounts formed on the support housing. An actuation lever extending outwardly from the second mounting arm permits the operator to cause pivotal movement of the pivoted second mounting arm to accept the tubular member to be finished between the mounting arms. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows, in conjunction with the accompanying sheets of drawings. It is to be expressly understood, however, that the drawings are for illustrative purposes and are not to be construed as defining the limits of the invention. 
       FIG. 1  is a top plan view of a belt grinder apparatus incorporating the principles of the instant invention, the support handle and associated housing being positioned for operation; 
       FIG. 2  is a bottom, front perspective view of the belt grinder apparatus depicted in  FIG. 1 ; 
       FIG. 3  is a perspective view of the support housing depicted in  FIG. 2 ; 
       FIG. 4  is a side elevational view of the grinder apparatus with the forwardly extending arms removed for purposes of clarity; 
       FIG. 5  is a side elevational view of the grinding apparatus with the support housing removed to depict the grinding belt; 
       FIG. 6  is a bottom plan view of the belt grinder apparatus with the support housing removed to better view the entrainment of the abrasive belt and the orientation of the mounting arms relative to the drive housing of the belt grinder apparatus; 
       FIG. 7  is a bottom plan view of the body and arm portions of the belt grinder apparatus as depicted in  FIG. 6  with the support housing removed; and 
       FIG. 8  is a rear elevational view of the body portion of the belt grinder apparatus with the support housing removed therefrom. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1-8 , a belt grinder apparatus  10  incorporating the principles of the instant invention can best be seen. The belt grinder apparatus  10  is constructed with a drive housing  12 , best seen in  FIG. 3 , having a drive motor  15  affixed thereto. The drive motor  15  can be operatively driven in a number of different ways, such as hydraulically or electrically, or from a rotary tool, but is preferably driven by a pneumatic source of pressurized air. Accordingly, the drive housing  12  has a control handle  13  affixed thereto to serve as a connector via the attachment nipple  14  to a remote source of pressurized air. The control lever  16  is associated with a valve that controls the influx of pressurized air into the pneumatic motor  15  to effect a rotational driving operation thereof. As the control lever  16  is closed toward its outwardly extending position shown in  FIGS. 1 and 3  against the control handle  13 , air is allowed to pass through the control handle  13  into the pneumatic motor  15 . Air is exhausted from the motor  15  in a conventional manner. 
   Opposite the drive housing  12  is a detachable support housing  17 , shown in  FIGS. 2 and 3 , which has a support handle  18  mounted thereto. The support housing  17  covers the otherwise open drive housing  12  and allows the support handle  18  to be utilized to help support the weight of the tool  10  during operation, with the belt grinder tool  10  being supported through use of the control handle  13  and the support handle  17 . Preferably, the support housing  17  is formed with supplemental handle mount  19  that is positioned to one side of the support housing  17  and is adapted for the mounting of the support handle  18 . Accordingly, the support handle  17  can be selectively mounted at the convenience and comfort of the operator from a generally central position on the support housing  17  to an offset position corresponding to the alternative handle mount  19 . 
   Referring now to  FIGS. 1 ,  2  and  5 - 7 , the belt grinder apparatus  10  is constructed with a pair of generally parallel oriented mounting arms  20 ,  30  projecting outwardly from the drive housing  12  generally perpendicularly to the orientation of the support handle  18 . Each of the mounting arms  20 ,  30  supports a run of the abrading belt  40  with an interior side  42  and an exterior side  43 . By positioning the double armed grinding tool  10  with a tubular member T to be finished between the mounting arms  20 ,  30 , the respective interior runs  42  can engage and finish opposite sides of a tubing member simultaneously. Either of the exterior sides  43  corresponding to the mounting arms  20 ,  30  can also be used to finish a metallic member in substantially the same manner as is known in the art, i.e. by engaging only one side of the member being finished. 
   The abrasive belt  40  is preferably an endless member that is entrained and driven for rotational operation relative to the mounting arms  20 ,  30 . The drive housing  12  supports a drive pulley  22  operatively associated with the pneumatic motor  15  to be rotatably driven when the control lever  16  is depressed to direct pressurized air into the motor  15 . The abrasive belt  40  extends from the drive pulley  22  around the tensioning pulley  25  mounted at the end of the first mounting arm  20 , then around a first fixed idler pulley  27  mounted on the drive housing  12 , then around the idler pulley  32  at the end of the second mounting arm  30 , then around a pivot pulley  35  connected to the inner end of the second mounting arm  30 , then around a second fixed idler pulley  37  mounted on the drive housing  12  and finally back around the drive pulley  22 . Thus, the abrasive belt  40  is entrained in serpentine path that wraps around the drive pulley  22 , the tensioning pulley  25 , the first fixed idler pulley  27 , the idler pulley  32 , the pivot pulley  35 , and the second fixed idler pulley  37 . Preferably, the drive pulley  22  is formed with a surface coating that enhances the frictional driving connection between the drive pulley  22  and the interior surface of the belt  40 . 
   The first mounting arm  20  includes a spring-loaded tensioning mechanism  26  that is connected to the tensioning idler  25  at the end of the first mounting arm  20 . The tensioning idler  25  is movable along the longitudinal main axis of the first mounting arm  20  toward and away from the drive pulley  22 . The movement of the tensioning idler  25  keeps a desired level of tension in the abrasive belt  40  for proper engagement with the member T to be finished by the engagement thereof with the abrasive belt. The idler  32  at the distal end of the second mounting arm  30  can be fixed in relation to the corresponding pivot pulley  35  at the inner end of the second mounting arm  30  because any deflection of the abrasive belt  40  associated with the second mounting arm  30  can be accommodated by the movement of the tensioning idler  25 . 
   The second mounting arm  30  is preferably pivotally mounted to the drive housing  12  concentric with the rotational axis of the pivot pulley  35 . Since the second mounting arm  30  pivots about the center of the pivot pulley  35 , the pivotal movement of the second mounting arm  30  relative to the first mounting arm  20  results in a corresponding tensioning movement of the tensioning idler  25 . Since the pivotal movement of the second mounting arm  30  covers only a few degrees, the amount of movement of the tensioning idler  25  is not substantial. The pivotal movement of the second mounting arm  30  allows the distal tips  29 ,  39  of the mounting arms  20 ,  30  to have an increased spacing to accept the passage of a tubular member T to be finished between the mounting arms  20 ,  30  by the interior runs  42  of the abrasive belt  40 . 
   An actuation lever  45  is affixed to the second mounting arm  30  and projects outwardly therefrom away from the rotating abrasive belt  40  to permit the operator to selectively pivot the second mounting arm  30  away from the first mounting arm  20  to increase the distance between the distal tips  29 ,  39  of the mounting arms  20 ,  30 . The tension in the abrasive belt  40  exerted by the tensioning mechanism  26  pulls the second mounting arm  30  toward the first mounting arm  20 , while a stop member (not shown) limits the inward pivoting of the second mounting arm  30  to prevent the distal tips  29 ,  39  from engaging. One skilled in the art will recognize that both the first mounting arm  20  and the second mounting arm  30  could be pivotally mounted; however, the best operative results were found when the first mounting arm  20  was fixed in relationship to the drive housing  12  while the second mounting arm  30  was pivotally mounted. 
   In operation, the double-armed belt grinder  10  is positioned at the tubular member T to be finished. By grasping the actuation lever  45  and pivoting the second mounting arm  30  outwardly away from the first mounting arm  20 , the distance between the distal tips  29 ,  39  of the mounting arms  20 ,  30  can be increased adequately to permit the passage of the tubular member T to pass between the tips  29 ,  39  to be engaged by both of the interior runs  42  of the abrasive belt  40 . The tension exerted by the tensioning mechanism  26  into the abrasive belt  40  through the tensioning pulley  25  draws the second mounting arm  30  inwardly toward the first mounting arm  20  to effect engagement of the tubular member T on substantially opposite sides thereof. Thus, opposing sides of the tubular member T can be finished simultaneously. 
   Depressing the control lever  16  on the control handle  13 , pressurized air is directed through the control handle  13  into the pneumatic motor  15  to power the rotation of the drive pulley  22  to drive the rotation of the endless abrasive belt  40 . The entire circumference of the tubular member T can be finished by simply rotating the belt grinder tool  10  about the tubular member T through a displacement of approximately ninety degrees. With conventional single arm miniature belt grinding tools, finishing the entire circumference of a tubular member T would require at least one hundred eighty degrees of movement of the belt grinder tool  10  relative to the tubular member T, assuming that both opposing sides of the abrasive belt would be utilized. Accordingly, the double-armed belt finishing tool  10  incorporating the principles of the instant invention reduces the operation time required to finish a tubular member T. 
   Replacement of the abrasive belt  40  is accomplished by releasing the tension from the tensioning mechanism  26  to permit the tensioning pulley  25  to be retracted along the first mounting arm  20  toward the drive pulley  22 . The abrasive belt can then be removed easily from the mounting arms and pulleys. The entrainment of a replacement abrasive belt  40  and the re-engagement of the tensioning mechanism  26  readies the tool  10  for operation. 
   Since the exterior runs  43  corresponding to the first and second mounting arms  20 ,  30  proximate the opposing sides of a conventional single armed miniature belt grinder tool, the double armed belt grinder tool  10  incorporating the principles of the instant invention can also be utilized in a conventional manner by engaging the metallic member to be finished with one of the exterior runs  43 . 
   Depending on the angle of deployment of the member to be finished and the discretionary comfort of the operator, the support handle  18  can be positioned at the central location on the support housing  17 , as is shown in  FIGS. 1 ,  2  and  4 , or disconnected and then re-mounted on the alternative mount  19  to locate the support handle  18  in an offset orientation with respect to the support housing  17 . As can be seen in  FIGS. 2 and 3 , the alternative mount  19  can be provided with a threaded bore  19   a  accessible from either side of the alternative mount  19  to permit a selective attachment of the support handle  18  in opposing orientations for the comfort of the operator. A third bore opening (not shown) formed in the side of the alternative mount  19  would enable the support handle  18  to be perpendicularly to that shown in  FIGS. 2 and 3 . 
   The invention of this application has been described above both generically and with regard to specific embodiments. Although the invention has been set forth in what is believed to be the preferred embodiments, a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure.

Technology Classification (CPC): 1