Patent Publication Number: US-6336270-B1

Title: Tube cutting and preparation tool and method

Description:
This patent application is a continuation of application Ser. No. 09/238,193, filed on Jan. 27, 1999 now U.S. Pat. No. 6,189,216 which claims benefit of U.S. provisional application Serial No. 60/072,633, filed Jan. 27, 1998, and incorporated herein by reference. 
    
    
     This invention relates to a hand held, battery operated tool for cutting copper tubing and electrical conduit and for preparing such conduit and copper tubes and fittings for connection. 
     BACKGROUND OF THE INVENTION 
     Plumbers and electricians must cut tubing to provide lengths suitable for use in installing plumbing systems and electrical conduits. While there have been powered cutters for many years, commercially available machines can hardly be considered to be portable. Proposals for hand held tools have had shortcomings that presumably resulted in a lack of commercialization. As a consequence, tubing and conduits are typically cut at a job site by a tradesman using a manually operated cutter. In many cases, a freshly cut tube is reamed to remove inwardly directed flashing that results from the cutting operation. As with tube cutting, the reaming operation is typically performed manually. 
     When a copper plumbing system is being installed it is necessary to burnish the outside diameter of tubing and the inside diameter of fittings in order that solder of a sweat joint will firmly and properly adhere to each tube and fitting being joined. 
     Since the described and other steps in preparing plumbing and electrical components for installation had been performed manually, there is need for a cordless, hand held, power operated tool for performing such cutting and burnishing operations. 
     SUMMARY OF THE INVENTION 
     The present invention provides a portable, hand held, battery operated tool for cutting copper tubing and electrical conduit. The tool preferably includes a power operated shaft for removably receiving deburring tools and brushes for preparing tubing ends and fittings to be secured together by sweat joints. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of the tool of the present invention; 
     FIG. 2 is a sectional view as seen from the plane indicated by the line  2 — 2  of FIG. 1; 
     FIG. 3 is a partially sectioned view of the tool as seen from the plane indicated by the lines  3 — 3  of FIG. 2; 
     FIG. 4 is an elevational view of the tool on a reduced scale showing the tool in a supported position; and, 
     FIG. 5 is plan view of a reamer for use with the tool. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, the hand held, battery operated tool of the present invention is shown generally at  10 . The tool  10  includes a housing having a main body  12  and a depending handle  14 . A battery  15  is secured to the base of the handle  14 . A motor  16  is mounted in a forward, removable extension  17  of the body  12  and electrically connected to the battery through conductors  21 , FIG.  2 . An on/off switch  18  is connected in the battery—motor circuit for control of the motor, FIG.  2 . 
     The extension  17  includes a body portion  19  which surrounds the motor  16 , FIGS. 2 and 3. The extension  17  has a closed outer end  17 E and an opposite open end communicating with a space within the body  12 . Fasteners F removably secure the extension  17  to the body  12 , FIG.  1 . 
     The body  12  delineates an open top work station  20 . A pair of driven rolls  22  are rotatively journaled in the body  12 . Journaling of the upper one of the rolls  22  is shown at  24  in FIG. 3. A gear train  25  drivingly interconnects the motor and the driven rolls  22 . 
     A cutter support  26  is reciprocatably mounted at a rearward end of the body  12 . A cutter wheel  28  is rotatively mounted on a forward end of the support  26  for selective movement into the work station  20  for engagement with a workpiece shown in phantom at  30  in FIG. 2. A spare cutter wheel  31  is removably secured to the rearward end of the support  26 . 
     A cutting trigger  32  is pivotally mounted near the junction of the body and handle  12 , 14  by a pivot  34 . The cutting trigger  32  is selectively movable into a space  35  in the handle portion  14  against the action of trigger spring  33 . A cavity  72  in cutting trigger  32  allows movement of the trigger spring  33 . The trigger  32  is an elongate member contoured to be ergonomically gripped by the fingers of an operator. Operation of the trigger for a cutting operation can be likened to the operation of a caulking gun. 
     The cutter support  26  includes a set of rack teeth  36  formed in its underside. A pinion  38  is rotatively mounted in the body  12 . The pinion  38  drivingly engages the holder rack teeth  36 . A drive link  40  is pivotally connected to the trigger  32  at  42 . The drive link  40  has upwardly directed rack teeth  44 . The drive link also has an underside cam surface  46 . The cam surface  46  is in engagement with a roller cam  48  rotatably mounted in the body portion. 
     When the trigger is depressed the drive link  40  is shifted to the left as viewed in FIG.  2  and is cammed upwardly by the roller cam  48 . Once cammed upwardly, the drive link closes the switch  18  to energize the motor  16 . The upward camming of the drive link brings its rack teeth  44  into driving engagement with the pinion  38 . Further depression of the trigger causes the pinion to rotate and drive the cutter support  26  forwardly to bring the cutter wheel  28  into compressive cutting engagement with a workpiece  30 . The engagement of the workpiece by the cutter wheel forces the workpiece into driven engagement with the drive rolls  22 . The cutter support has a space  49  to the left, as viewed in FIG. 2, of the rack teeth  44  limiting the length of the rack to prevent the cutter  28  from being driven into the drive rolls  22  in the absence of a workpiece. 
     A driven cross shaft  50  is provided. The cross shaft includes a bore  51  which has spaced end portions that are square in cross section, FIG.  2 . These end portions each may be likened to the aperture in a mechanics&#39; socket. In the disclosed and preferred embodiment, the cross shaft  50  is connected to the gear train  25  such that whenever the motor  16  is operated both the driven wheels  22  and the cross shaft rotate. 
     As pictured in FIGS. 1 and 3 an inside diameter brush  52  is removably connected to the cross shaft  50  at the upper side as viewed in FIG.  3 . At the lower side an outside diameter brush  54  is removably mounted. A reaming cutter  56 , FIG. 5, for removing internal burs from the cut end of a tube may be selectively connected to the driven cross shaft  50 . 
     The connection of the removable brushes  52 , 54  and the reamer  56  to the cross shaft  50  is best understood by reference to FIGS. 3 and 5. As seen in FIG. 5, the reamer has an elongate square stem  58 . The stem has an O-ring groove  60  formed near the end of the stem remote from cutter teeth  62   a-c . As can be seen by an examination of FIG. 3, the removable brushes and reamer are connected to the cross shaft  50  by inserting the stem  58  into a square bore  51  in the cross shaft. An O-ring in the groove  60  provides retention of a removable brush or reamer stem in the cross shaft bore by compressive engagement with a cylindrical section  61  of the bore  51 , FIG.  3 . The square stem coacts with the square end portions of the bore  5   1  to provide a driving interconnection between the removable brush or reamer and the cross shaft. 
     The reamer cutting teeth  62   a-c  provide one of the outstanding features of the invention. The teeth are in a stepped construction with, for example, the teeth  62   a  sized to ream ½ inch tubes, the teeth  62   b  sized for ¾ inch tubes and the teeth  62   c  sized for 1 inch tubes. 
     In order to prevent accidental energization of the motor when the unit is not in use, a trigger lock and release  66  is provided. The trigger release  66  is pivotally mounted on the pivot  42 . The trigger release  66  is biased into a locked position by a spring biased trigger plunger  68 , such that coacting locking surfaces at  70  are engaged. When the motor is to be energized the trigger release  66  is depressed enabling depression of the trigger  32 . 
     Ear extensions  74 , FIGS. 1 and 4, on the end section  17  are provided to stabilize the tool  10  when in the supported position of FIG. 4. A mechanism is preferably provided for locking the trigger in its on position. The disclosed locking mechanism as shown in FIGS. 1 and 2 has a spring biased trigger locking pin  76 . The locking pin may selectively be depressed to insert an end portion of it into a trigger aperture  78  to lock the trigger in an on position. 
     Operation 
     When an operator wishes to produce a workpiece from a tube which may be either copper tubing or electrical conduit, he first measures the tube and marks the location where a cut is to be made. Next, the tube is inserted into the work station as indicated at  30  in FIG.  2 . The marked location is then aligned with the cutter  28 . Next the trigger release  42  is depressed to place it in the release position and allow the trigger  32  to be depressed into the handle space  35 . Depression of the trigger  32  causes the drive link  40  to shift to the left as viewed in FIG.  2 . Coaction of the cam surface  46  and the roller cam  48  causes the rack teeth  44  to engage the pinion  38 . Concurrently, the switch  18  is turned into its “on” position to energize the motor  16 . 
     As the trigger is further depressed, the cutter support  26  moves to the right as viewed in FIG. 2, bringing the cutter  28  into engagement with the tube  30  and the force of that engagement in turn establishes a driven relationship between the tube and the drive rolls  22 . The drive rolls rotate the workpiece as the cutter is pressed against it to severe the workpiece from the balance of the tube being cut. 
     Once the workpiece has been cut, the trigger is released. Once closing pressure is removed from the trigger, the trigger spring  33  returns the trigger to its “off” position and concurrently the trigger plunger  38  returns the trigger lock and release  66  to its locked position. 
     If internal flashing on the cut end of the workpiece is to be removed, a reaming operation is now performed. To that end a reamer  56  is inserted into the aperture of the drive cross shaft  50 . The tool is placed in the support position of FIG. 4, the trigger is again moved to its “on” position and the trigger locking pin  76  is depressed to insert it into the trigger aperture  78 . On release of manual pressure from the trigger release, friction between the walls defining the aperture  78  and the trigger pin  76  will maintain the pin  76  in the aperture to hold the trigger in the “on” position. Assuming the workpiece is a ⅜″ diameter tube, the end to be reamed will be axially aligned with the reamer and pressed axially toward the reamer to engage the teeth  62   b  to remove any flashing that resulted from the cutting operation. 
     When the workpiece is a copper tube, it is inserted into an outside diameter brush  54  of the appropriate diameter to burnish a small end section preparatory to the formation of a sweat joint. The operator will also burnish the sweat joint surfaces of a fitting by inserting an appropriately sized inside diameter brush  52  into the fitting. 
     When performing the reaming or burnishing operation, an operator will use one hand to steady the tool in its supported position while positioning fittings and workpieces relative to the brushes and reamer with the other hand to effect the reaming and burnishing operations. 
     Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction, operation and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.