Abstract:
A portable, hand held exhaust pipe cutter having an air motor to drive a cutting wheel arranged parallel to a drive shaft of the air motor by an angle head gearing device. The cutter makes straight cross-sectional cuts through cylinders by using a feed lever pivotally attached to the air motor that engages the cylinders to be cut and guides them into engagement with the cutting wheel. The feed lever on an opposing end includes a handle that extends along the air motor so that a user can grip both the control lever of the air motor and the handle of the feed lever simultaneously with a single hand.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is division and claims the benefit under 35 U.S.C. 121 of the 35 U.S.C. 111(a) application Ser. No. 09/277,291, filed Mar. 26, 1999, now abandoned, which in turn claims the benefit to the 35 U.S.C. 111(b), provisional application 60/104,911, filed Oct. 20, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to air tools. More particularly, it relates to an anglehead air tool which is useful in the removal of worn exhaust system components, such as steel tubing of various sizes, from the underside of a vehicle. 
     2. Description of the Related Art 
     The standard procedure for exhaust system installers has been to remove the rusted and worn exhaust system components from the underneath of a motor vehicle with an oxygen-acetylene cutting torch. The most serious problem associated with the use of a cutting touch involves the fire hazard when locating high intensity heat to combustible products, frequently found in close proximity to desired location of the cut. In addition, when using an oxygen-acetylene torch, it is particularly difficult to make an accurate and clean cut, about the circumference of the tube. An accurate and clean cut is desirable in order to eliminate any further preparation, of the newly cut surface, for subsequent installation of replacement components. Accordingly, the prior art has focused on the development of a cutting tool which safely produces a clean and smooth cut, about the circumference of the tube. 
     In U.S. Pat. Nos. 3,805,383, and 3,834,019, a portable reciprocating type saw attachment is disclosed having a saw body and a sabre blade receiving bracket. The blade receiving bracket is clamped to the blade-end of the body, by means of a spring. The blade receiving bracket provides a lower tube receiving recess, having a right angle shape, for locating the exhaust system tubing against the reciprocating blade. The blade receiving recess is pivotally mounted for movement between an open, tubing receiving position, and a closed position, upon completion of the cutting cycle. Movement, by the operator, between the open and closed positions is accomplished by pressing, in a direction away from the saw body, on a lever to cause the tubing to close against the saw blade. 
     It is believed, however, that certain disadvantages are inherent in the sabre saw and attachment design which must be overcome to provide an improved device. Initially, spring mounting of the tube receiving attachment to the saw body, may not rigidly clamp an exhaust tube in relation to the saw and blade, when used in the awkward and confined work space which is typically encountered during motor vehicle repair. Metal sabre saw blades are also easily broken when used at various angles, in tight locations. Moreover, a sabre saw is a large tool, and is not easily accessible to a wide variety of cutting locations. It is also heavy and would normally require the operator to use both hands to hold the tool. Thus, an operator would require assistance in holding a work piece. There is a need, therefore, for a durable high speed, hand-held, exhaust cutting tool characterized by ease in operation, and which provides a smooth even cut of the exhaust system components, when used in tight work spaces. 
     Accordingly, it is an object of the present invention to provide an air device for cleanly and efficiently cutting a tube. 
     It is another object of the invention to provide an improved cutting device for removing the worn exhaust system components, of various diameter sizes within a predetermined range, from a motor vehicle. 
     It is another object of the present invention to provide a hand-held, high speed cut-off tool which is useful for working in tight areas. 
     It is yet another object of the present invention to provide a cut-off tool, for removing the worn exhaust components from a motor vehicle, which results in an accurate and smooth tube section, about the circumference, in order to eliminate further surface preparation of the cut surface, prior to the installation of standardized replacement parts. 
     SUMMARY 
     The present invention provides an air tool for removing worn exhaust components from a motor vehicle. In combination with an air tool having an air motor, an air motor body, an angle head drive means connected to the air motor and body, and a cutting wheel and axle assembly connected to the drive means, the improvement for making a straight cross-sectional cut through a cylinder which comprises a feed lever, having a pivot point, a first end extending above the cutting wheel, and a second end extending below the air motor body as a handle for applying a pressure while the air tool is in use, the feed lever being pivotally mounted on the housing at the pivot point such that the first end guides the wheel in making the straight cross-sectional cut when a pressure is applied to the second end by hand. 
     Unless specifically defined otherwise, all technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1, is a side plan view of the air tool saw. 
     FIG. 2, is top elevation view of the air tool saw with a cut-away of the anglehead body. 
     FIG. 3, is a top elevation view of the air tool saw. 
     FIG. 4, is second top elevation view of the air tool with a cut-away of the anglehead body to illustrate another embodiment of the drive means. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides an air tool for removing worn exhaust components from a motor vehicle. The saw is characterized by high speed, light weight, and small size, for easy insertion into the tight work areas often associated with the underneath of a vehicle, to be repaired. The air tool is operable with one hand, by means of a tube engaging feed lever, having a scissors like action with respect to the wheel, for accurately and cleanly cutting through exhaust system components. 
     In a basic configuration, the air tool comprises an air motor, an air motor housing and an angle head drive. A bearing sleeve is located within the housing through which a drive shaft, driven by the air motor, extends from the air motor into an anglehead drive body. The anglehead drive body is in rigid connection with the air motor housing. Within the anglehead drive body, is an angle drive means to translate the rotational axis of a cut-off wheel perpendicular to that of the motor. The cut-off wheel is supported on an axle in perpendicular rotational engagement to the drive shaft. The axle extends outwardly from the anglehead drive body through a sleeve and a seal. The cut-off wheel is rigidly connected to the axle, for easy removal, by a fastener such as a nut, bolt, screw, or clip. 
     To provide for a smooth and even cut, about the circumference of the tube, the cut-off tool is provided with a feed lever which is operated by hand in a scissors like manner with respect to the wheel. This lever is used to hold the uncut portion of the tube firmly against the wheel throughout a cutting cycle. The feed lever has a first portion, a middle portion and a second portion. The middle portion is in pivotal connection with at least one side of the air motor body, in a plane substantially parallel to the plane of the cut-off wheel. The first portion extends in a spaced relationship over the wheel. The second portion extends below the motor body, and is used as a handle, for resiliently biasing the first portion, of the feed lever, against the tube. At least two roller assemblies are provided. The roller assemblies are attached, transversely, to the first portion, of the feed lever. In this manner, the entire device is easily rotated about the section of tube, to be cut, to assist in a clean cut, and in easily locating the cut when working in tight spaces. 
     Referring now to the drawings, wherein like numerals represent like elements, there is shown generally therein at  10 , in FIG. 1, an air motor of a construction which is well known in the art such as the air motor tool manufactured by MAC Tool Company, Model No. ADG410AH. Air motor  10  includes an air chuck  12  which connects to a compressed air supply used to drive the motor preferably at an average air consumption of approximately 3 cfm. An air control lever  14  is used to control the motor  10  speed. The motor  10  speed preferably translates to a desired cut-off wheel  16  speed of between 6,000 and 20,000 rpm. Air control lever  14 , includes an air control safety  18 . Drive shaft  22 , in FIGS. 2 and 3, is driven at one end by the air motor and is located through a bearing sleeve (not shown) within the air motor housing for outward extension into a sealed anglehead drive unit  24 . The anglehead drive unit  24  is connected to motor body  10  by an assembly means  26 , such as a large nut on threads in the motor body  10 . 
     With reference now to FIGS. 2 and 4, located within anglehead drive unit  24 , is a convention drive system, such as a combination of spiral  28  (FIG.  4 ), or bevel gears  30  (FIG.  2 ), at shaft end  22 , for translation of the rotation of the cutting wheel  16 , perpendicular to that of the rotational axis of the air motor  10 . The drive system is made such that the combination of the air motor rotational speed, gear ratios, and cut-off wheel diameter translate to a desired cut-off wheel  16  speed of between 6,000 and 20,000 rpm. In a preferred embodiment, shaft  22  end  33  is rotationally supported by a sleeve and bearings, such as roller bearings  37 . An axle  34  is connected at one end to a second conventional drive, such as gear  32 , and extends outwardly, through a seal and bearing assembly  36 , through the anglehead drive body  24 . The seal and bearing assembly  36  prevents leakage of lubricant within drive body  24 . The cut-off wheel  16  is rigidly fastened, by means of a nut, bolt or screw  38 , to axle  34  for removable replacement of the wheel  16 . Cut-off wheel  16  is desirably between 12.7 and 17.78 centimeters in diameter and has an abrasive carbide cutting material on the surface. 
     It is important, in the removal of worn exhaust system components, to ensure a clean-cut and it is desirable to have one hand free in the operation of the cutting device. These operations are provided by means of a tube engaging feed lever  40 , shown generally in FIGS. 1 and 4. The feed lever  40  is desirable made of forged steel but may be cast of metal or molded of high impact plastic. Feed lever  40  is hand operated by squeezing portion  46  against motor body  10  in a scissors like action with respect to the cut-off wheel  16 . The feed lever  40  is thereby used to engage tube  42  (FIG. 3) against cut-off wheel  16 , throughout completion of a cutting cycle. In this manner, feed lever  40  facilitates a precision 90° cross-sectional cut through the tube  42 , thereby minimizing the amount of preparation, of the resulting cut, prior to the replacement of commonly used exhaust system replacement parts. 
     Tube engaging feed lever  40  has a first portion, shown generally as  44 , a middle portion  50 , and a second portion  46 , which serves as a handle. Feed lever  40  is in lateral pivotal connection, at  43  of middle portion  50 , with at least one side of the air motor body  10 , in a plane substantially parallel to the plane of the cut-off wheel  16 , by means of pivot pin  52 , threaded into the motor body  10 , and secured by a retaining ring, pin, nut, or screw (not shown). First portion  44 , of the feed lever  40 , extends in a spaced relationship over the cut-off wheel  16 . Second portion  46  is useful, as a handle, for resiliently biasing first portion  44 , of the feed lever  40 , against tube  42 , in a scissors like action, with respect to the cut-off wheel  16 . In a preferred embodiment, at least two roller assemblies comprising a cast or welded pin, or a screw, axle  56 , and a roller  58 , are connected to the first portion  44  of feed lever  40  to assist in rotating the wheel  16  around the tubing throughout the completion of the cutting cycle. In this manner, the operator may either simultaneously rotate the cut-off tool about the circumference of the section of tubing, to be cut, at a cutting depth equal to the thickness of the tubing wall or may cut cleanly and completely through the entire diameter of the exhaust system tube. 
     With reference now to FIG. 4, a top elevation view of the invention is generally shown with the upper surface of the anglehead body removed, for illustration of one embodiment of the drive means. Here, spiral gear  28  is shown in connection with drive shaft  22 . In perpendicular rotational engagement with spiral gear  28  is bevel gear  32  and axle  34 . Axle  34  extends through sleeve and bearing assembly  36 , in anglehead body  24 , and fastens to cut-off wheel  16 . Cut-off wheel  16  is disposed for free rotation within a safety guard recess  60 , of safety guard  62 . Guard  62  is firmly connected (not shown), to either the axle or anglehead body by a weld, or fastener such as a nut, bolt, or screw, located for tensioned travel within a slot in a guard mounting for positional adjustment of the guard, with respect to the wheel. In FIG. 1, guard  62  is shown of a design which allows for a maximum opening for receiving tube  42 . Guard  62  maybe rotated in a clockwise or counter clockwise direction in relation to the wheel in order to close the spaced relationship between feed lever  40  and guard  62  by loosening the fastener and sliding the fastener within the slot of the guard attachment bracket. In this manner the operator may direct the spray of sparks in a desired direction during the cutting cycle. 
     With reference now to FIG. 4, it is shown generally therein an alternative embodiment of the perpendicular drive arrangement within a top elevation cutaway view of the anglehead body  24 . Here, bevel gear  32  is provided near shaft  22  end in alternative to the spiral gear  28  of FIG.  4 . The end of shaft  22  is preferably stabilized with a bearing and sleeve  35 . 
     The foregoing description is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction as described above. Accordingly, all suitable modifications and equivalents may be resorted to falling within the scope of the invention as defined by the claims which follow.