Abstract:
A tubing cutter apparatus including a rotary cutting mechanism having an open area for receiving a length of tubing and a cutting blade for engaging the tubing may be driven by a rotary power source such as a handheld power tool or a self-contained drive motor. The apparatus includes a gear system for rotating the cutting mechanism about the tubing and a coupling mechanism for coupling the rotary power source to the gear system. A clamp comprising a slotted tubular plate spring protruding from a handle case of the apparatus in longitudinal alignment with the open area of the cutting mechanism enables the apparatus to clampingly engage a length of tubing to be cut by pushing flanged edge walls of the slot against the length of tubing, which may be in a location with limited accessability, such as within the wall of a structure.

Description:
BACKGROUND 
     The background of the invention will be discussed in two parts. 
     FIELD OF THE INVENTION 
     The invention relates to tubing cutting apparatus for cutting copper tubing and the like, and more particularly, to hand-held as well as hands-free apparatus wherein a power tool or self-contained battery power is used to activate or power the cutting mechanism. 
     PRIOR ART 
     A variety of tubing cutting devices have been developed over time having configurations generally adapted for use in cutting tubing in a circular path. Such cutting devices have progressed from the common hacksaw for sawing through the tubing to handheld rotatable “C” shaped cutting head structures wherein a cutting blade is clamped onto the tubing to be cut and then is rotated by hand about the tubing thereby cutting the tubing. Current state of the art structures incorporate electrical power for rotating the cutting mechanism around the tubing to perform the cutting operation. A search of the prior art has not disclosed the tube cutting apparatus of the present invention, however, devices of interest are shown and described in the following: U.S. Pat. No. 4,831,732 issued to Garton on 23 May 1989 relates to a handheld C-shaped structure which is clamped onto the tubing and then rotated by hand to perform the cutting of the tubing; and U.S. Pat. No. 4,890,385 issued to VanderPol, et al. on 2 Jan. 1990 relates to an automatic feed system for a powered tube cutter having a rotatable tube accommodating cutting head with a cutting arm pivotally attached to the cutting head. 
     In accordance with features of the present invention, there is provided a new and improved power operated automatic tubing cutting apparatus having a C-shaped structure which is easily clamped onto the tubing to be cut and is then power rotated about the tubing to perform the cutting operation. Three embodiments of the invention are provided, two configured to be hand held during the cutting operation and the other configured for hands-free attachment to the tubing during the cutting operation. 
     SUMMARY 
     In accordance with the present invention, there are disclosed embodiments of an improved tubing cutter apparatus which provides easier and faster modes of operation. The invention is particularly suitable for use either with battery power or with a handheld power tool for rotating the cutting mechanism about the tubing. It is also suitable for hands-free use wherein the apparatus is affixed to the tubing during the cutting operation. The tubing cutter apparatus includes a cutting mechanism having a central area for receiving a length of tubing and a cutting blade located in the central area for engaging the tubing. Provided is a gear system for causing rotation of the cutting mechanism about the tubing and a coupling mechanism for coupling a rotary driving element of a power tool or self-contained motor to the gear system for rotating the cutting mechanism. The foregoing and other objects, features and advantages of the invention will become readily apparent from a reading of the specification when taken in conjunction with the drawings in which like references numerals refer to like elements in the several views. 
    
    
     
       DRAWINGS 
         FIG. 1  is a perspective view illustrating an embodiment of tubing cutter apparatus in accordance with the present invention; 
         FIG. 2  is an enlarged exploded view illustrating mounting of the cutting head to the gear system of the embodiment of  FIG. 1 ; 
         FIG. 3  is a perspective view illustrating a second embodiment of the tubing cutter apparatus in accordance with the invention; 
         FIG. 4A  indicates mounting of the cutting head to the gear system of the embodiment of  FIG. 3 ; 
         FIG. 4B  illustrates arrangement of the gear system of the embodiment of  FIG. 3 ; 
         FIG. 4C  is an exploded view of the gear system of the embodiment of  FIG. 3 ; 
         FIG. 5A  indicates closing of the cutting head of the invention tubing with the tubing to be cut; 
         FIG. 5B  indicates the cutting head properly positioned about the tubing in preparation for cutting the tubing; 
         FIG. 5C  indicates the cutting blade of the cutting head properly positioned for cutting the tubing; 
         FIG. 6A  illustrates initial cutting of the tubing by rotation of the cutting head of the invention about the tubing; 
         FIG. 6B  shows continued rotation of the cutting head about the tubing to continue the cutting operation; 
         FIG. 6C  shows nearly complete cutting head rotation about the tubing; 
         FIG. 7A  is a cut-away view illustrates the interior mechanism of the cutting head with the locking lever in the open position; 
         FIG. 7B  illustrates partial closure of the locking lever urging contact of the cutting blade with the tubing; 
         FIG. 7C  illustrates full closure of the locking lever with resultant cutting of the tubing; 
         FIG. 8  is a cross section view of the cutting head of the invention; 
         FIG. 9  illustrates a third embodiment of the tubing cutter apparatus in accordance with the invention; 
         FIG. 10A  is an exploded view illustrating mounting of the cutting head of the invention to the gear system of the embodiment of  FIG. 9 ; and 
         FIG. 10B  is an exploded view illustrating the gear mechanism of the embodiment of  FIG. 9 . 
     
    
    
     DESCRIPTION 
     Referring to  FIG. 1  there is illustrated a representative embodiment of the tubing cutting apparatus of the invention, generally designated  10 , showing the method in which the apparatus  10  is used in cutting a tubing  20 . In this embodiment the cutting apparatus  10  is used in combination with hand-held power tool  11 . As shown, the tubing  20  is located in a confined area as indicated by the interior wall at  17 , framework stud  18 , and a section of interior drywall  19 . Portions of drywall  19  are not shown so as to illustrate access to the tubing  20 , the configuration of cutting apparatus  10  providing sufficient clearance to position the cutting head, generally designated  12 , onto the tubing  20 . Also, since the driving force of cutting head  12  is obtained from the spaced apart power tool  11 , there is no problem in operating the cutting head  12  within the confined area. 
     Power tool  11  may for example be an electric drill or an electric screwdriver, and may be of either the cord or cordless type. The gripping handle  13  of apparatus  10  is grasped by one hand  14   a  of the user while the power tool  11  is held in the other hand  14   b ; the cutting apparatus  10  then positioned onto the tubing  20  to be cut. The rotary driving element  11   a  of power tool  11  is inserted into or connected to the gear coupling mechanism, generally designated  15 , connected to the gear system of the cutting apparatus  10 . With activation of the power tool  11  the gear system of the cutting apparatus causes rotation of the cutting head  12  whereby after a few revolutions of cutting head  12 , typically in two to three seconds, tubing  20  is cut as desired. The coupling mechanism  15  may include a universal joint (not shown) having one end coupled to the rotary driving element  11   a  of the power tool  11  and the other end connected to the gear system of cutting apparatus  10 . 
       FIG. 2  is an exploded view illustrating an embodiment of the cutting apparatus  10  of  FIG. 1  and the method of driving the cutting mechanism  10 . Shown is cutting head  12 , cover  16 , gear system  21 , and base plate  22 . Cover  16  includes coupling mechanism  15  and three each of threaded retaining bolts  16   a  and retaining screws  16   b  (only one designated). Also shown is opening  23  for receiving tubing  20 . 
     Gear system  21  includes in planar arrangement and sequence of connection, a C-shaped gear  25 , a pair of intermediate circular gears  27 ,  28  that do not engage each other, and a circular driving gear  29 . Both intermediate gears  27 ,  28  engage C-shaped gear  25  and on the opposite side engage driving gear  29 . In this manner driving gear  29  engages and simultaneously rotates both intermediate gears  27 ,  28  and in turn intermediate gears  27 ,  28  engage and simultaneously rotates C-shaped gear  25 . Two intermediate gears  27 ,  28  are required in that for some rotational positions, one or the other of intermediate gears  27 ,  28  will be in the gap in the C-shaped gear defined by shoulders  24 ,  26  and hence will be out of contact with C-shaped gear  25 . Thus, intermediate gears  27 ,  28  are positioned so that at least one of these gears is always in contact the C-shaped gear  24  such that there is no break in the rotation of C-shaped gear  25 . Power tool connector member  15  extends through cover  16  and is secured to driving gear  29  by means of screws  16   b . C-shaped gear  25  has a raised portion  25   a  for attachment to cutting head  12  as will be described. 
     Base plate  22  has three mounting posts  22   c , two for rotatably receiving intermediate gears  27 ,  28  which are secured by two of retaining bolts  16   a  to base plate  22 , and one for receiving the third retaining bolt  16   a , the retaining bolts  16   a  also serving to secure cover  16  to base plate  22  thereby capturing gear system  21 . A semi-cylindrical bearing sleeve  22   a  is vertically attached to base plate  22  and when the cutting apparatus is assembled extends upward through the open area of C-shaped gear  25  to provide a bearing about which gear  25  rotates. 
       FIG. 3  illustrates in perspective view a second embodiment, generally designated  30 , in accordance with the invention. Shown in longitudinally extending arrangement is a handle case having a battery compartment  31 , hand gripping portion  32 , driving motor compartment  33  with on-off switch  34 , and extending base section  35  having cover plate  36 . Cutting head  12  is shown attached to the apparatus gear system, as will be explained, for rotating cutting head  12 . When on-off switch  34  is in the “on” position the batteries activate the driving motor which in turn through the gear system activates cutting head  12  to cut tubing  20 . In operation, the user grasps the hand gripping handle section  32 , pushes the cutting head  12  onto tubing  20  at the selected cutting location and operates on-off switch  34  effecting rotation of the cutting head  12  about tubing  20 . After a few revolutions tubing  20  is cut as desired. As illustrated the tubing  20  is located in a confined area, however, since the configuration of apparatus  30  provides that the driving force is sufficiently spaced apart from the cutting head  12 , the apparatus  30  does not cause unwanted interference in the vicinity of the tubing  20  during the cutting procedure. 
       FIGS. 4A-4C  are exploded views illustrating positioning of the components of the embodiment  30  ( FIG. 3 ) of the invention,  FIG. 4A  illustrating mounting of the cutting head  12  to a C-shaped gear  25  of the gear system  21 ,  FIG. 4B  illustrating arrangement of the gear system, and  FIG. 4C  being an exploded view of the gear system. The gear system of embodiment  30  is the same as that of embodiment  30  of  FIG. 1  except for the means for powering driving gear  29  as will be described. 
     As indicated in  FIG. 4A  cutting head  12  is fixedly attached at fastener locations  25   b  (two shown) of a raised circular portion  25   a  of C-shaped gear  25 , the raised portion providing adequate clearance for cutting head  12  to rotate freely above cover plate  36  in response to rotation of C-shaped gear  25 . Extending base section  35  is formed as a cavity for receiving the gear system of embodiment  30 , the base of the cavity having an integral vertically extending semi-cylindrical fixed bearing sleeve  35   a  around which the C-shaped gear  25  rotates, C-shaped gear  25  having a raised portion  25 A extending upward through cover  36  to be attached to cutter  12 . Bearing sleeve  35   a  is shown more clearly in  FIG. 4C  as being integral to and extending upward from the base of cavity  35   b  and forming a bearing about which C-shaped gear  25  rotates in response to activation of the embodiment driving motor. 
       FIG. 4B  illustrates arrangement of the gear system  21  within the planar bottomed cavity, generally indicated as  35   b , of extending base section  35  and as captured by cover  36 . The gear system  21  is the same as that of embodiment  30  of  FIG. 3  except for the addition of gear  46  which is activated by the motor to rotate driving gear  29 . Cavity  35   b  can be formed having a planar base integral to extending base section  35  or alternatively by a planar bottom cover for extending section  35 . Extending section  35  and cover plate  36  have corresponding entrance openings  40 ,  41 , respectively, for accepting tubing  20 . Entrance  40  is generally U-shaped, the base of the “U” being circular in configuration and having a diameter generally the same as the width of the entrance opening  40 . Cover plate entrance  41  is terminated in an enlarged circular opening  41   a  having a diameter adequate for receiving raised portion  25   a  of gear  25  therethrough. Gear  25  is C-shaped in a circular manner with a planar bottom and having teeth on the periphery thereof, the opening  40  corresponding to opening  41  of cover  36 . Inwardly of the teeth of gear  25  is the raised, or stepped-up, portion  25   a  forming a platform extending upwardly through the circular opening  41   a  of cover plate  36  for cutting head  12  to be fixedly attached thereto at fastener points  25   b . With attachment over cavity  35   b , cover  36  forms a semi-circular channel defined by bearing sleeve  22   a  and the sidewalls of cavity  35   b  through which the gear  25  rotates. Thus, as described, cover plate  36  captures the gear  25  within the cavity  35   b  and the raised stepped platform of gear  25  extends through cover  36  to provide adequate clearance for cutting head  12  to rotate. 
     As previously mentioned, the gear system  21  is the same as that of embodiment  30  of  FIG. 3  except for gear  46  which is activated by the motor to rotate driving gear  29 . That is, the output shaft of the driving motor extends into the cavity of extending section  35  and is terminated by gear  46  which engages gear  29  to drive cutting head  12  through the combination of intermediate gears  27 ,  28  and C-shaped gear  25 . Thus, with rotation of the motor shaft, gear  46  rotates gear  29 , which in turn rotates intermediate gears  27 ,  28  simultaneously, which in turn rotates C-shaped gear  25 , which in turn rotates cutting head  12 . 
     Cover plate  36  is secured to extending section  35  by means of fastening screws  45  as indicated. This arrangement establishes and maintains a spaced apart relationship between cover plate  36  and the base of the cavity of extending section  35 , cover plate  36  preventing the various gears from coming off of their support posts. The circular open area  41   a  of the cover plate  36  corresponds approximately to the open area  40  in the base of the cavity in extending section  35 . When attached, open area  41   a  is located in line with and opposite the open area  40  in base of the cavity in extending section  35 . The cutting head  12  is located in line with the open area  41   a  upwardly from cover  36 . C-shaped gear  25  is rotatably mounted about the bearing sleeve  22   a  intermediate the cavity base and the cover plate  36  in line with the open area  41   a  of cover plate  36 . Gear  25  is secured to the adjacent side of cutting head  12  by appropriate fastening means at fastener locations  25   b.    
       FIG. 4C  is an exploded view of the gear system further illustrating the mounting of the gears  25 ,  27 ,  28  and  29 . As indicated, C-shaped gear  25  is rotatably mounted about the bearing sleeve  22   a , gears  27  and  28  are rotatably mounted to posts  43  which are secured to the base of the cavity, and gear  29  is rotatably mounted to post  44  which is also secured to the base of the cavity. Motor shaft gear  45  extends into the cavity positioned to engage gear  29 . 
       FIGS. 5A-5C  illustrate the manner in which the cutting head  12  is positioned onto tubing  20  for both the embodiment of  FIGS. 1 and 3 , the cutting head and basic gear system being the same for each.  FIG. 5A  indicates tubing  20  closing, as indicated by the arrow, with the receiving opening of the cutting head  12 . As will be further explained below, locking lever  50  is in the open position for allowing spring urged recession of the rotatable cutting blade  51  (shown in phantom in  FIG. 5A ). Shown partially in phantom are fixed position rotatable support rollers  52 ,  53  for positioning tubing  20  within the cutting head  12  and facilitating easy rotation of cutting head  12  about tubing  20  during the cutting operation.  FIG. 5B  shows tubing  20  properly positioned in cutting head  12  against support rollers  52 ,  53  but not yet clamped by cutting blade  51 .  FIG. 5C  shows clamping of tubing  20  by cutting blade  51  whereby, in cooperation with support rollers  52 ,  53 , tubing  20  is firmly positioned for cutting. Cutting blade  51  includes spring means and cam configuration, the spring means urging recession of cutting blade  51  away from tubing  20  when lever  50  is in the open position; the cam configuration overcoming the spring means when lever  50  is in the closed position to force penetrating contact of the cutting blade  51  with the tubing  20 . 
       FIGS. 6A-6C  illustrate the tubing cutting procedure as the gear system rotates the cutting head  12  about the tubing  20 . For illustrative purposes the rotation is shown as clockwise although this is not an operational requirement. In  FIG. 6A  lever  50  is closed to force cutting blade  51  into penetrating contact with tubing  20  and to effect initial cutting of tubing  20  by rotation of cutting head  12  about stationary tubing  20 , support rollers  52 ,  53  facilitating easy rotation of cutting head  12 .  FIG. 6B  shows further rotation of cutting head  12  about tubing  20  to continue the cutting rotation with  FIG. 6C  illustrating a nearly complete cutting rotation. After a few rotations tubing  20  is cut as desired. 
       FIGS. 7A-7C  illustrate the manner in which spring means  70  is used in cutting head  12  for urging recession of cutting blade  51  away from tubing  20  when lever  50  is in the open position; lever  50  having a cam portion  50   a  that at closure of lever  50  overcomes the spring means  70  to force cutting contact of the cutting blade  51  with the tubing  20 .  FIG. 7A  illustrates initial positioning of tubing  20  within the cutting head  12  with the locking lever  50  in the open position. The cam portion  50   a  of locking lever  50  rides on a tension spring  70 , spring  70  having an extending portion  70   a  with a slot  70   b  for receiving cutting blade  51  therein. When lever  50  is in the open position spring  70  is in the unloaded state and cutting blade  51  in not impacting tube  20  in the cutting mode.  FIG. 7B  illustrates partial closure of the locking lever  50  with the cam portion  350   a  of lever  50  depressing to partially load spring  70  thereby urging contact of the cutting blade  51  with the tubing  20 .  FIG. 7C  illustrates complete closure of the locking lever  50  whereby the spring  70  is loaded sufficiently to force cutting blade  51  to cut the tubing  20 . After cutting of the tubing  20  the lever  50  is opened thereby unloading spring  70  whereby the cutting blade  51  returns to its non-cutting mode. 
       FIG. 8  illustrates in cross-sectional view the mounting of cutting head  12  to the C-shaped gear  25  of the gear system  21  of the invention as seen looking into the opening  25  as shown in  FIG. 4A . As mentioned, cutting head  12  is fixedly attached to gear  25  by fastener means at locations  25   b  with gear  25  mounted for rotation about semi-cylindrical bearing sleeve  35   a , bearing sleeve  35   a  integral to and extending upward from the base of extending portion  35 . The raised portion  25   a  of gear  25  protrudes through opening  41   a  of cover plate  36  and behind bearing sleeve  35   a , fastener locations  25   b  provided at the top of the raised portion  25   a . Support rollers  52 ,  53  are also shown. 
       FIGS. 9 ,  10 A and  10 B illustrate a third embodiment  90  of a tubing cutting apparatus in accordance with the invention. In this embodiment a modified gear system compartment and gear system is shown wherein the attached cutting head  12  is mounted at a generally 90 degree angle to the previously described longitudinally extending arrangement of  FIG. 3 . The cutting head  12  and mounting thereof to the gear system is the same as previously described for the second embodiment. 
       FIG. 9  shows in longitudinally extending arrangement a handle base having a battery compartment  91 , hand gripping portion  92 , and motor compartment  93 . Also located on compartment  93  (not shown) is the motor on-off switch. Compartment  93  further includes a flexible resilient clasp  94  for attaching embodiment  90  to a tubing  20 . Mounted at a right angle to compartment  93  is a gear system compartment  95  having cutting head  12  mounted thereon as previously described. Gear system compartment  95  has base  95   a  and cover  95   b . In operation of this embodiment the cutting head  12  and the attachment means  91  are aligned and suitably attached to the tubing  20  as indicated, after which the motor is started and the tubing  20  cut as desired. It is not necessary to hold the apparatus in place by hand during the cutting operation. 
       FIG. 10A  is an exploded view illustrating mounting of the cutting head  12  to the gear system of the embodiment  90  of  FIG. 9 . As shown, in this third embodiment the cutting head  12  and mounting thereof to the gear system is the same as previously described for the second embodiment. 
       FIG. 10B  is an exploded view illustrating the gear compartment and modified gear system of this embodiment. The modified gear system is the same as the gear system of the embodiment of  FIG. 4B  except since gear compartment  95  is mounted at a generally 90 degree angle to the previously described longitudinally extending arrangement of  FIG. 3 , the driving gear  29  is connected directly to the motor output shaft. In the operation of embodiment  90  the cutting head  12  and the attachment means  94  are aligned and suitably attached to the tubing  20  as indicated, after which the motor is started and the tubing  20  cut as desired. With this embodiment it is not necessary to hold the apparatus in place by hand during the cutting operation. 
     The invention has been shown and described with reference to specific illustrated embodiments. It is realized that those skilled in the art may make changes or modifications in the invention without departing from the true scope and spirit of it. Therefore, the scope and spirit of the invention should not be limited to the embodiments discussed, but only by the invention as claimed.