Abstract:
A device for creating a hole in a tube. The tube includes a saddle clamp positioned thereon. The saddle clamp has a threaded cutting chamber, and the cutting device is insertable and engageable with the threaded saddle clamp, the cutting device having a cutting edge. The cutting device is engageable with the cutting chamber to axially move therethrough towards the tube as the blade device is rotated.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION  
       [0001]     This application claims priority from U.S. Provisional Patent Application No. 60/848,431, filed Sep. 29, 2006, herein incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to the field of drilling and specifically to small bore drilling of tubular plumbing components or material.  
       BACKGROUND OF THE INVENTION  
       [0003]     There exist many applications requiring a hole to be made in a tube. For example, in plumbing systems, there is often a need to add an apparatus, such as a chemical cleaner dispenser, to an existing system requiring a hole to be made in the systems tubing.  
         [0004]     Current systems typically utilize a punching mechanism that concentrates the force in a singular point on the outside wall of the tube. Other systems simply have a continuous rough cutting surface that can tear material from the outside wall, eventually producing a hole. However, such prior art methods and apparatus for creating a hole in thin walled tubing often results in distortion of the tube, the generating of metal burrs, or the generating of other defects in the hole or tubing that make mating of the hole with another tube or device difficult.  
         [0005]     It is preferential for aesthetic purposes, and vandal-resistance purposes or reduction of inadvertent damage that the hole be made on the portion of the tube facing the wall. However, this presents difficulty due to the small clearance space between the tube and the wall. As such, prior art systems either require removal or rotation of the tube to allow the hole to be drilled or the drilling of a hole through both walls of the tube and the subsequent capping of the unneeded hole.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention relates to apparatus and methods for cutting a hole in a tube or a tubular plumping component. In one exemplary embodiment, the present invention relates to an apparatus having a saddle clamp and a cutting device. The saddle clamp affixes to a tube and includes a threaded chamber for receiving the cutting device. The cutting device is preferably cylindrical and is likewise threaded to engage the chamber and includes at one end a cutting edge for engaging and cutting the tube and, at the opposite end, an actuation point for rotating the cutting device. In one embodiment, the actual thread pitch is based on the number of cutting edges and their shape. In one embodiment, the cutting edges are of a specific shape on the cutting face, with the cutting edges having a specific relief angle.  
         [0007]     These and other objects, advantages, and features of the invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like elements have like numerals throughout the several drawings described below.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is an exploded view of one embodiment of the present invention;  
         [0009]      FIG. 2  is a partial cross-sectional view of  FIG. 1  along line A-A (without the tool depicted);  
         [0010]      FIG. 3A  is a profile illustration of one embodiment of a cutting device of the present invention; and  FIG. 3B  is a close-up of the cutting teeth;  
         [0011]      FIG. 4  illustrates one embodiment of the present invention for use in a urinal application providing a connection between a primary tube and a secondary tube; and  
         [0012]      FIG. 5A  illustrates a side-view of the cutting device of the present invention; and  
         [0013]      FIG. 5B  illustrates a side-view of the cutting device of  FIG. 5A  rotated 60 degrees about line B-B. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]     The present invention relates to methods and apparatus for cutting a hole in a tube. In one embodiment, illustrated in  FIG. 1 , the present invention relates to a system  101  for cutting a hole (not shown) in a material, such as a tube  103 . A saddle clamp  105  (shown assembled in  FIG. 4 ) engages the tube  103 . The saddle clamp  105  comprises a front strap  107  and a rear strap  109 . In one embodiment, the saddle clamp  105  is designed to engage the tube  103  such that the front strap  107  and the rear strap  109  both include a semi-circular curved portion ( 110 ,  111  respectively) for receiving the material (tube)  103 . The front strap  107  and the rear strap  109  are engageable with each other to form a ring having an opening in the middle for receiving the tube  103  therethrough. When assembled the saddle clamp  105 , i.e., the front strap  107  and the rear strap  109 , circumscribe the tube  103 . The front strap  107  includes a cutting chamber  113 . The cutting chamber  113  extends through the front strap  107  forming a passage therethrough perpendicular to a tube  103  disposed in the saddle clamp  105 . In one embodiment, the cutting chamber  113  provides a path through the front strap  107  to a portion of the tube  103 . The cutting chamber comprises an inner wall  115 ; and in one embodiment, the inner wall  115  of the cutting chamber  113  is threaded. In one embodiment, the cutting chamber  113  protrudes beyond the front strap  107  forming a cylindrical outcropping  116  having an outer wall  117  and continuing the inner wall  115 . In one exemplary embodiment, the outer wall  117  is threaded.  
         [0015]     The present invention includes as part of the system  101 , a cutting device  120  which is engageable with the saddle clamp  105 . In an exemplary embodiment shown in profile view in  FIG. 2 , and in a perspective view in  FIG. 3A  and front elevations  FIGS. 5A and 5B , the cutting device  120  is cylindrical in shape, having a first end  121  and a second end  122  with a sidewall  123  therebetween which is substantially cylindrical in shape. In one embodiment, the sidewall  123  has threads (see  FIG. 5A ) on its outer surface to operatively engage the threaded inner wall  115  of the cutting chamber  113 . The first end  121  includes at least one cutting edge  125 , best shown in  FIG. 3B . In one embodiment, the cutting edge  125  is positioned at the end of at least one cutting tooth  132 . In an exemplary embodiment, the cutting edge  125  is defined by a plurality of separate cutting edges  125  positioned on a plurality of cutting teeth  132 . In an exemplary embodiment, the cutting edge  125  defines a circular cutting path (not shown), with the cutting teeth  132  rotating about the longitudinal axis A-A ( FIG. 1 ) of the cutting device  120 .  
         [0016]     In the present invention, the cutting edge  125  is discontinuous and is formed on at least one cutting tooth  132  which protrudes from the first end  121 . In an exemplary embodiment, the cutting edge  125  is formed on multiple cutting teeth  132  which serve to stabilize the cutting device  120  during cutting, as each cutting tooth  132  enters the cut, the forces of other ones of the cutting teeth  132  engaged in the cut are counterbalanced.  
         [0017]     To effect a cut, it is required that the cutting forces be concentrated between the cutting device  120  and the tube  103  being cut; thus generating a high local stress point on the tube  103 . It is generally accepted that this condition is difficult to maintain as the cutting device  120  advances into and through the tube  103  as more of the cutting edge  125  comes into contact with the tube  103 . The profile of the tube  103  to be cut can further complicate the process of cutting a hole, thereby making use of the described cutting device  120  more important.  
         [0018]     The at least one cutting edge  125  engages a portion  133  of wall  134  of the tube  103  (see  FIG. 1 ), the portion  133  being positioned opposite the passage (the cutting chamber  113 ) through the front strap  107 . In one embodiment, the cutting device  120  is rotated with the threads of its sidewall  123  engaging the threads of the cutting chamber  113  inner sidewall  115 , resulting in movement of the cutting device  120  through the cutting chamber  113  relative to the saddle clamp  105  and the tube  103 . The at least one cutting edge  125  engages the portion  133  and rotates about a longitudinal axis A-A as the cutting device  120  is rotated, thus defining a cutting path (not show). In one embodiment, the cutting path (not shown) is substantially circular. In one embodiment, the rotation of the cutting device  120  results in the threads on the outerwall  123  engaging those of the inner wall  115 , advancing the cutting device  120  along the longitudinal axis A-A. This forces the cutting edge  125  against the portion  133  by gradual movement of the cutting device  120  forward in the cutting chamber  113  as the cutting edge  125  cuts into the wall  134 .  
         [0019]     Several factors that need to be balanced in determining the size and number of cutting teeth  132 . For example, the cutting edge  125  can be designed to cut a range of different tube diameters, for example tubes ranging from ¾-inch to 1½-inch outside diameter with a wall thickness of approximately 1/32-inch. In one embodiment, a thicker wall section of the tube  103  could be cut by making the cutting device  120  longer. In one embodiment, the length of the cutting edge  125  is optimized for the tube wall thickness and the minimum clearance available to access the tube  103 .  
         [0020]     To highlight the challenge in cutting through a wide variety of tube diameters, one can compare the diameter of the hole cut by the cutting device  120  to the diameter of the tube  103  through which the hole is cut. In one embodiment, in the smallest diameter the ratio of cut hole to the tube diameter is 0.333 and in the largest case this ratio is reduced to 0.167. The large tube diameter being two-times larger, and therefore the surface to be cut is flatter.  
         [0021]     In one embodiment, the cutting device  120  comprises a “fishtail” type design having angled cutting edges (see  FIGS. 3A and 3B ). In one embodiment, the angled cutting edges are curvilinear in nature such that they substantially define a circulating cutting path. As shown in  FIG. 3A  and  FIG. 3B , the “fishtail” design includes a first angled face  135  and a second angled face  136 . The first angled face  135  has an outer cutting edge  150  and an inner edge  151 . The farthest protruding portion of the first angled face  135  forms a cutting point  137 . In the embodiment shown in  FIGS. 3A and 3B , the cutting device is rotated counterclockwise (for a user viewing from the head  127 , along the side wall  123  to the second end  122 , the head  127  would be rotated clockwise). This rotation results in the cutting point  137  forming the leading point of the tooth  132 . The second angled face  136  has an outer edge  152  and an inner edge  153 . In one embodiment, the angled faces  135  and  136  are convex, allowing the edges  152  and  153  to engage the tube rather than the surface of the angled faces  135  and  136 . In one embodiment the angle of the first angled face  135  with respect to a plane formed by a circular cross-section of the cutting device  120  is less than 145 degrees; and the angle of the second angled face  136  is more than 45 degrees.  
         [0022]     The “fishtail” design of one embodiment of the present invention is intended to minimize distortion of the tube  103  by directing forces inward toward the axis of the hole being cut. Material displacement takes place only on the inside of the circular cutting path; and thus the distortion occurs primarily on the discarded slug.  
         [0023]     In one embodiment, the angle of the “fishtail” design is determined primarily by the smallest diameter tube that would be encountered. This allows the “fishtail angle” design to first engage the tube  103  with the outer edge  152 . Moreover, concentration of cutting forces on the cutting point  137  and outer edge  152  also serves to quickly and easily penetrate the tube  103 , of particular importance in applications such as hard-chrome plated plumbing fixtures.  
         [0024]     For embodiments with only one cutting tooth  132 , a moment is generated in the cutting device  120  perpendicular to a longitudinal axis of the cutting device  120 . This moment increases the load on the cutting surface, increasing the potential to fracture the cutting device  120 . Though it does not increase the difficulty to cut, it does seek to deflect the cutting edge  125  and change the course of the cutting edge  125  while exposing it to shear stress along its length. With only one tooth  132 , all of the cutting forces, tensile and torsional, are concentrated in one small area. Adding a second cutting tooth  132 , which is 180° from the first, results in a balanced dispersion of cutting forces, canceling this moment and directing the force axially into the tube  103 . Having both the cutting teeth  132  engaged in the cut simultaneously balances and reduces the tensile and shear loads, but increases the torsional load on the cutting device  120 .  
         [0025]     In other embodiments, the cut being made is an interrupted cut increasing the chance of fracturing the cutting tooth  132 . In one embodiment, three cutting teeth  132  are used to maintain a balance of the forces and manufacturability. With three cutting points there is always at least one point in contact with the tube  103 ; particularly in the critical early phase of starting the cut. In one embodiment, four or more cutting teeth are utilized. Four or more cutting teeth would be an improvement by reducing the feedrate or depth of cut per the cutting teeth  132 , but more difficult from the perspective of cutting device manufacture.  
         [0026]     The pitch of the threads (sidewall  123  of the cutting device  120  and inner wall  115  of the cutting chamber  113 ) is chosen to achieve an appropriate advance of the cutting device  120  through the cutting chamber such that the cutting device  120  would advance at such a rate so as to not damage the cutting edges,  150 ,  151 , the cutting point  137  or the surface to be cut. Advancing too quickly could break the cutting device  120  rendering it unusable. However, an aggressive feedrate is required to penetrate some material, such as nickel chrome plating used in plumping fixtures. Advancing too slowly will allow the hard chrome to distort and dull the cutting edges,  150 ,  151 . which also leads to the cutting device  120 . In one embodiment, a standard pitch thread of, 124 threads per inch, is utilized.  
         [0027]     In one embodiment, the cutting device  120  includes an actuation mechanism, such as the head  127  for rotating the cutting device  120 , causing the cutting device  120  to pass axially through the cutting chamber  113 . In an exemplary embodiment shown in  FIG. 1 , the saddle clamp  105  is removably affixed to the tube  103  with a portion of the tube  103  exposed via the cutting chamber  113 . The cutting device  120  is engageable with the cutting chamber  113  such that the cutting edge  125  engages the tube  103 . In one embodiment shown in  FIG. 3A , the actuation mechanism comprises a shaped head  127  at the second end  122  opposite the at least one cutting edge  125  for engagement by a tool  130 . For example, the head  127  may be shaped to correspond to a tool  130  (see  FIG. 1 ) allowing for engagement of the cutting device  120  by the tool  130 . One of ordinary skill in the art will appreciate the multitude of ways to engage the cutting device  120 ; and thus, the head  127  could, for example, include without limitation a Philips type slot, a straight slot, or a hex-head design.  
         [0028]     In a further embodiment, the present invention relates to a method of cutting a hole in the tube  103 . The rear strap  109  and the front strap  107  of the saddle clamp  105  are positioned on the tube  103  and affixed to each other with the tube  103  disposed therebetween. The cutting device  120  is inserted into the threaded cutting chamber  113 , such that the at least one cutting edge  125  is proximate the tube  103 . The cutting device  120  is turned so as to interact the threads of its sidewall  123  with the threads of the inner wall  115  of the cutting chamber  113 . Rotation of the cutting device  120  draws the cutting device  120  into the cutting chamber  113 , and the cutting edge  125  approaches the portion  133  of the tube wall  134 . As the cutting point  137  contacts the portion  133  of the tube wall  134 , the cutting edge  125  traverses a circular path, cutting into the tube wall  134 . The cutting edge  125  cuts a hole through the tube wall  134  as the cutting device  120  is rotated. The interaction of the threaded sections  115  and  123  advances the cutting edge  125  forward (along A-A) as the cutting device  120  is rotated. One of ordinary skill in the art will appreciate that a plurality of revolutions of the cutting device  120  may be necessary to completely cut a hole into the tube wall  134 , depending in large part on the thickness of the tube wall  134 .  
         [0029]     In one embodiment, the system  101  of the present invention is engagable with a secondary tube  104  providing a connection between the secondary tube  104  and the primary tube  103 . For example, in one embodiment the tube  103  is a part of a water closet fixture. After the hole is cut in the tube  103 , as described above, a secondary tube  104  is inserted into the cutting chamber  113 . In an exemplary embodiment shown in  FIG. 4 , the secondary tube  104  includes a threaded nut  144  which corresponds to threads on the outer wall  117  of the cutting chamber  113 . The nut  144  can be drawn down to fix the secondary tube  104  to the saddle clamp  105 , providing fluid communication between the tubes  103  and  104 . In one embodiment, a seal  142  is provided between saddle clamp  105  and the tube  103  ( FIG. 1 ). The seal  142  assists in sealing the tube  103  and the secondary tube  104 .  
         [0030]     In another embodiment (shown in  FIGS. 1 and 2 ), the tool  130  ( FIG. 1 ) is provided which comprises at a first end an opening for engaging the actuation mechanism of the cutting device  120  and at a second end an opening for engaging the nut  144  of the secondary tube  104  ( FIG. 2 ). In one embodiment, the tool  130  is provided with a slot for insertion of a leverage device (not shown).  
         [0031]     The foregoing description of embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the present invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the present invention. The embodiments were chosen and described in order to explain the principles of the present invention and its practical application to enable one skilled in the art to utilize the present invention in various embodiments, and with various modifications, as are suited to the particular use contemplated.