Patent Publication Number: US-2019178431-A1

Title: Pressurized push rod system and device

Description:
PRIORITY CLAIM 
     This application claims the benefit of U.S. Provisional Application No. 62/598,403, filed Dec. 13, 2017, which is incorporated herein by reference in its entirety, including but not limited to those portions that specifically appear hereinafter, the incorporation by reference being made with the following exception: In the event that any portion of the above-referenced provisional application is inconsistent with this application, this application supercedes said above-referenced provisional application. 
    
    
     BACKGROUND 
     1. Technical Field 
     This disclosure relates to a system and device pushing instruments into piping. More specifically, the disclosed system provides fittings enclosing a length of pipe which allow the pipe to be pressurized to inflate a bladder attached to a pipe. This device includes a rigid but flexible length of pipe which allows air to be transferred from an air source at a first end into an inflatable bladder on the second end. 
     2. Description of the Related Art 
     Since the aqueducts of ancient Rome, plumbers have been installing, maintaining, and repairing pipes that bring water to certain fixtures and drain that water away from the fixtures after use. While plumbing technology has improved since the plumbers of ancient Rome made indoor flowing water possible, there are still significant problems with maintaining and repairing pipes. One problem is that pipes, which are frequently buried underground at substantial depth, under cement, or under structures, may rupture, crack, or otherwise break. Because these pipes are buried, they may be difficult and expensive to repair, leaving few options for preventing gases or fluids within the pipes from escaping into the earth surrounding the pipe. It should be noted that many different types of pipes carry all types of fluids and gases between two points. Further, the system and device disclosed herein is suitable for use with any pipe carrying any fluid or gas. However, for the purposes of explanation, the system and device disclosed herein will be discussed with respect to pipes supplying water to a residence or commercial building and pipes draining water away from a residence or commercial buildings. It can be readily appreciated that sewage, for example, leaking from a broken or worn out pipe is a substantial problem, posing both health concerns and environmental concerns. 
     As previously discussed, accessing pipes buried underground or under structures, or in other places, may be difficult or impossible in various situations, without, for example, demolishing a building and refitting a new section of pipe to repair, for example, a sewer line. Thus, frequently, the only access available to plumbers to repair or maintain a pipe is frequently from inside the pipe. In other words, pipes can be disassembled and disconnected from each other to provide a plumber with access to the inside of the pipe. Frequently pipe repairs that would otherwise be too expensive, difficult, or impossible to repair are fixed by patching or sealing holes, cracks, or other problems from the inside of the pipe. 
     One conventional solution to fix pipes from the inside of the pipe is shown in  FIG. 1 .  FIG. 1  illustrates a pipe  105 . In  FIG. 1 , pipe  105  may be a conventional sewer pipe of any conventional diameter. Disposed within pipe  105  is a fiberglass rod  110  that is created by attaching short sections of fiberglass rods by screwing a following rod into a leading rod which creates a connection point, such as connection  115   a  and connection  115   b . Fiberglass rod  110 , made from several sections of smaller fiberglass rods connected together, may include a hook  120  or other instrument that allows a user, such as a plumber, to manipulate an air bladder  125  within pipe  105 . In the example of  FIG. 1 , pipe  105  has suffered a failure that requires repair, such as a crack or a hole developed from corrosion, or the like. Thus, air bladder  125  may be fitted with a patch  130 , which may be any patch type known in the art. Exemplary patches may be fiberglass infused with epoxy resin and hardener, joint sealing compound, rubber, or any other type of patch material. Patch  130  may be placed by first manipulating fiberglass rod  110  into pipe  105  at the location of the failure such that patch  130  is positioned immediately proximate to the failure. Next, the user may inflate air bladder  125  via air hose  135 , another hose that is separate and distinct from fiberglass rod  110 . As air bladder  125  is inflated, air bladder  125  pushes patch  130  onto the failure and may be used to secure patch  130  in place, as necessary, as patch  130  cures. Air bladder  125  may also be treated with a release agent which allows the user to deflate the bladder, after patch  130  has cured and set, which allows the user to withdraw air bladder  125 , through pipe  105 . 
     As shown in  FIG. 1 , pipe  105  includes a 90° bend  140 , which may also be referred to as an “elbow” joint in pipe  105 . Fittings such as 90° bend  140  are commonly used in all plumbing applications and pose significant problems for repairing a failure in a pipe. As shown, fiberglass rod  110  may be inserted in the X direction, as shown in  FIG. 1  up to the point of 90° bend  140 . Because of 90° bend  140 , fiberglass rod  110  is forced around the bend to proceed in a Y direction within pipe  105 . Thus, in order to push fiberglass rod  110  further down pipe  105  a user must push in the X direction in order to push bladder  125  in the Y direction. This force creates substantial tensional stress on fiberglass rod  110 , most especially around connection joints between the sections of fiberglass rod  110 , such as connection  115   a.    
     Frequently, this tensional stress results in fiberglass rod  110  shearing, cracking, or otherwise breaking just forward or behind connection point  115   a , for example, because fiberglass rod  110  is far less flexible at connection points, such as connection  115   a , than at other points along fiberglass rod  110 . These failure points are identified as approximate failure areas  145   a  and  145   b . Once fiberglass rod  110  breaks at approximate failure areas  145   a  and  145   b , it may be difficult to retrieve a broken section of fiberglass rod  110  and bladder  125 . Frequently, air line  135  may be used to retrieve the broken section of fiberglass rod  110 , although because air line  135  is not specifically designed for this purpose, air line  135  may detach from bladder  125 , leaving both bladder  125  and fiberglass rod  110  stuck within pipe  105 . Thus, not only is the repair not completed, the problem is compounded by a length of broken fiberglass rod  110  and bladder  125  being stuck within pipe  105 . Fiberglass rod  110  is typically inflexible around connection points, such as connection  115   a  to bend with pipe  105  such that fiberglass rod  110  is a last repair option, for many plumbers, due to the risk of the rod breaking during a repair attempt. Thus, fiberglass rod  110  is a less ideal solution to apply a patch to the inside of pipe  105 . 
       FIG. 2  illustrates a connection joint  200 , such as connection  115   a  of fiberglass rod  110 , shown in  FIG. 1 . Connection joint  200  includes a first section of fiberglass rod  205 , including a male threaded end  210 , and a second section of fiberglass rod including a female threaded end  215 . First section of fiberglass rod  205  may be threaded, by male threaded end  210 , into second section of fiberglass rod  220 , by female threaded end  215 . In this manner, many different fiberglass rods may be fitted together to create a fiberglass rod, such as fiberglass rod  110  shown in  FIG. 1 , of any length. While there is no inherent problem with the approach of threading a first section of fiberglass rod  205  into a second section of fiberglass rod  220  to create a fiberglass rod of a desired length, the fiberglass, nylon, or other synthetic and natural materials that may be used, lack the flexibility to successfully navigate piping without breaking and creating additional problems using screw together threaded type fittings. 
     Accordingly, a need exists for, and it is at least one object of this disclosure to provide, a system which allows a user to reliably insert a push rod into a pipe and inflate a bladder. Further, another object of this disclosure is to provide a device which allows a push rod to include joints, as necessary, with sufficient flexibility to negotiate various fittings in piping is needed. Finally, it is an object of this disclosure to provide a device which eliminates a need for multiple lines, such as air lines, to be inserted into a pipe with a push rod to execute a bladder based patch of piping. 
     SUMMARY 
     Disclosed herein is a device. The device includes a length of pipe. The length of pipe may include a first fitting connecting, by a first connection, to a first end of the pipe. The length of pipe may further include a second fitting connecting, by a second connection, to a second end of the pipe. The first connection and the second connection are air-tight. 
     Further disclosed herein is a system. The system includes a length of pipe. The system further includes a first fitting connecting at a first end of the pipe at a first connection. The system further includes a second fitting connecting a second end of the pipe at a second connection. The system also includes an air bladder connected to the second end of the pipe. The first connection and the second connection are air tight. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate various embodiments of a pressurized push rod device and system. 
         FIG. 1  illustrates prior art solution to making a bladder based patch on an inside surface of a pipe. 
         FIG. 2  illustrates a prior art fiberglass rod used to position the bladder, as shown in  FIG. 1 . 
         FIG. 3  illustrates a pressurized push rod device. 
         FIG. 4  illustrates an exemplary air fitting for terminating the pressurized push rod device shown in  FIG. 3 . 
         FIG. 5  illustrates a pressurized push rod system for making a bladder based patch on an inside surface of a pipe. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the following description, for purposes of explanation and not limitation, specific techniques and embodiments are set forth, such as particular techniques and configurations, in order to provide a thorough understanding of the device disclosed herein. While the techniques and embodiments will primarily be described in context with the accompanying drawings, those skilled in the art will further appreciate the techniques and embodiments may also be practiced in other similar devices. 
     Reference is now made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts. It is further noted that elements disclosed with respect to particular embodiments are not restricted to only those embodiments in which they are described. For example, an element described in reference to one embodiment or figure, may alternatively be included in another embodiment or figure regardless of whether or not those elements are shown or described in another embodiment or figure. In other words, elements in the figures may be interchangeable between various embodiments disclosed herein, whether shown or not. 
       FIG. 3  illustrates a pressurized push rod device  300 . Pressurized push rod device  300  includes a cylindrical hose, tube, or pipe  305 , having a void  305   a  with an internal diameter disposed therein. In one embodiment, pipe  305  may be implemented as an HDPE (High Density Polyethylene) plastic pipe capable of maintaining an internal pressure of up to approximately 128 pounds per square inch of pressure in a substantially 1″ internal diameter pipe. Other materials may be used to construct pipe  305 , such as various other types of plastics, including poly-paraphenylene terephthalamide, nylon, twaron, thermoplastics, polyamides, and other similar materials. One advantage of such materials is that these materials are flexible over a given length of piping while still being rigid enough to push and pull through a pipe, such as a sewer pipe. For example, while the term flexible may be broadly interpreted, an example of flexible pipe may be defined as pipe that may be deflected by more than or equal to 3 inches per foot of pipe. That is, a flexible pipe may be bent by 3 inches per foot of pipe before breaking, kinking, splitting, or interrupting a void  305   a  within pipe  305 . However, at the same time, a flexible pipe, to be considered rigid enough to be pushed and pulled through a pipe may be deflected by less than 9 inches per foot of pipe before breaking, kinking, splitting, or interrupting a void  305   a  within the pipe. Thus, in a preferable embodiment, pipe  305  may be constructed from materials that may be deflected or bent anywhere between 3 and 9 inches per foot of pipe. In this manner, pipe  305  may be implemented using any of the foregoing materials. Flexibility of pipe  305  is necessary to allow pipe  305  to move through various fittings within piping, such as sewer piping, without kinking, breaking, splitting or interrupting the void  305   a  within pipe  305 . 
     Pipe  305  may also be implemented in any length. For example, pipe  305  may be implemented in ten or twenty or twenty five foot lengths to meet the requirements of a particular situation. Shorter lengths of pipe  305  may be desirable as pipe  305  may be connected to another length of pipe to lengthen pipe  305 , while at the same time increasing portability of pipe  305 . However, a length of pipe  305  is generally irrelevant for the purposes of disclosure. 
     Pipe  305  may be terminated on a first end by a first fitting  310 . First fitting  310  may be implemented using hard plastics or, more preferably, a metal such as brass, bronze, aluminum, steel, or other similar or suitable material. First fitting  310  may include a hose barb  315  which prevents first fitting  310  from being removed from pipe  305 . For example, hose barb  315  may include a surface that is parallel to a horizontal (around the circumference) cross section of pipe  305  which has a diameter slightly larger (on the order than of less than a millimeter) than an internal diameter of pipe  305  and which digs into or seats into material around the internal diameter of pipe  305 . When hose barb  315  digs into or seats into the material around the internal diameter of pipe  305 , not only is a seal formed between first fitting  310  and pipe  305 , but hose barb  315  also prevents first fitting  310  from being removed from pipe  305  without destroying pipe  305 . 
     First fitting  310  further includes crimp retainer  320   a  and crimp retainer  320   b . Crimp retainer  320   a  and crimp retainer  320   b  are spaced to accommodate a standard crimp ring to be installed on an outside surface of pipe  305  but also between crimp retainer  320   a  and crimp retainer  320   b  to provide an air tight seal between first fitting  310  and pipe  305 . First fitting  310  further includes shoulder  325   a  and shoulder  325   b , which may be implemented as separate shoulders or may be concentric and circumferential around first fitting  310 . Shoulder  325   a  and shoulder  325   b , whether implemented as separate shoulders or a concentric and circumferential ring may be larger in diameter than an outside diameter of pipe  305 . In this manner, first fitting  310  may be seated within pipe  305  by inserting first fitting  310  into pipe  305  to the point where pipe  305  comes into contact with shoulder  325   a  and shoulder  325   b  (or with the concentric circumferential ring defined by shoulder  325   a  and shoulder  325   b ). The term concentric may be interpreted as referring to a relative size of shoulder  325   a  and shoulder  325   b  being larger than an outside diameter of pipe  305  while the term circumferential refers to the concentric shoulder  325   a  and shoulder  325   b  extending around a horizontal (around a circumferential) cross section of first fitting  310  such that shoulder  325   a  and shoulder  325   b  acts as a stop for inserting first fitting  310  into pipe  305 . 
     First fitting  310  may include a void  330 , which allows air to pass through first fitting  310  into pipe  305 . Void  330 , which is disposed within first fitting  310 , may include threads  335 , which allow first fitting  310  to attach to another pipe or to an air compressor fitting, such as air compressor fitting  340  directly or via another threaded fitting  345 . In this manner, pipe  305  may receive compressed air from an air compressor. 
     Pipe  305  may be terminated on a second end by a second fitting  350 . Second fitting  350  may be substantially identical in construction to first fitting  310 . For example, second fitting  350  may be implemented using hard plastics or, more preferably, a metal such as brass, bronze, aluminum, steel, or other similar or suitable material. Second fitting  350  may further include a hose barb  355  which prevents second fitting  350  from being removed from pipe  305 . For example, hose barb  355  may include a surface that is parallel to a horizontal cross section of pipe  305  which has a diameter slightly larger (on the order than of less than a millimeter) than an internal diameter of pipe  305  which digs into or seats into material around the internal diameter of pipe  305 . When hose barb  355  digs into or seats into the material around the internal diameter of pipe  305 , not only is an air tight seal formed between second fitting  350  and pipe  305 , but hose barb  355  prevents second fitting  350  from being removed from pipe  305  without destroying pipe  305 . 
     Second fitting  350  further includes crimp retainer  360   a  and crimp retainer  360   b . Crimp retainer  360   a  and crimp retainer  360   b  are spaced to accommodate a standard crimp ring to be installed on an outside surface of pipe  305  but also between crimp retainer  360   a  and crimp retainer  360   b  to provide an air tight seal between second fitting  350  and pipe  305 . Second fitting  350  further includes shoulder  365   a  and shoulder  365   b , which may be implemented as separate shoulders or may be concentric and circumferential around second fitting  350 . Shoulder  365   a  and shoulder  365   b , whether implemented as separate shoulders or a concentric and circumferential ring may be larger in diameter than an outside diameter of pipe  305 . In this manner, second fitting  350  may be seated within pipe  305  by inserting second fitting  350  into pipe  305  to the point where pipe  305  comes into contact with shoulder  365   a  and shoulder  365   b  (or with the concentric circumferential ring defined by shoulder  365   a  and shoulder  365   b ). Again, the term concentric may be interpreted as referring to a relative size of shoulder  365   a  and shoulder  365   b  being larger than an outside diameter of pipe  305  while the term circumferential refers to the concentric shoulder  365   a  and shoulder  365   b  extending around a horizontal cross section of second fitting  350  such that shoulder  365   a  and shoulder  365   b  act as a stop for inserting second fitting  350  into pipe  305 . 
     Second fitting  350  may include a void  370 , which allows air to pass through second fitting  350  into an air bladder. Void  370 , which is disposed within second fitting  350 , may include threads  375 , which allow second fitting  350  to attach to another pipe or to an air bladder fitting, such as air bladder fitting  380  directly or via another threaded fitting  385 . In this manner, an air bladder (which is discussed below) may be attached to pipe  305  and receive air from an air compressor via pipe  305 . As air is applied within pipe  305 , air may pass through first fitting  310  into pipe  305 , from pipe  305  through second fitting  350 , and into an air bladder. In most situations, as will be discussed below, an air bladder may be fully inflated at approximately 30 PSI of pressure. Thus, while pipe  305  may safely contain a much higher pressure without rupturing, pipe  305  may be pressurized to approximately 30 PSI of pressure with the compressed air to fully inflate an air bladder. However, it is noted that air, while preferable, is not the only material with which pipe  305  may be pressurized. Other fluids, such as water or hydraulic fluid, for example, may be used to inflate an air bladder. Thus, pipe  305 , including first fitting  310  and second fitting  350  serves as pressurized push rod device  300 . 
       FIG. 4  illustrates an exemplary air fitting  400  for terminating a pressurized push rod device, such as pressurized push rod device  300 , shown in  FIG. 3 . Indeed, fitting  400  may be similar in both implementation and description to first fitting  310  and second fitting  350 , shown in  FIG. 3 . 
     Fitting  400  may be implemented using hard plastics or, more preferably, a metal such as brass, bronze, aluminum, steel, or other similar or suitable material. Fitting  400  may further include a hose barb  410  which prevents fitting  400  from being removed from a pipe, such as pipe  305 , shown in  FIG. 3 . For example, hose barb  410  may include a surface that is parallel to a horizontal cross section of pipe  305  which has a diameter slightly larger (on the order than of less than a millimeter) than an internal diameter of pipe  305  which digs into or seats into material around the internal diameter of pipe  305 . 
     Fitting  400  further includes crimp retainer  415   a  and crimp retainer  415   b . Crimp retainer  415   a  and crimp retainer  415   b  are spaced to accommodate a standard crimp ring to be installed between crimp retainer  415   a  and crimp retainer  415   b  to provide an air tight seal between fitting  400  and pipe  305 . Fitting  400  further includes shoulder  420   a  and shoulder  420   b , which may be implemented as separate shoulders or may be concentric and circumferential around fitting  400 . Shoulder  420   a  and shoulder  420   b , whether implemented as separate shoulders or a concentric and circumferential ring may be larger in diameter than an outside diameter of pipe  305 . In this manner, fitting  400  may be seated within pipe  305  by inserting fitting  400  into pipe  305  to the point where pipe  305  comes into contact with shoulder  420   a  and shoulder  420   b  (or with the concentric circumferential ring defined by shoulder  420   a  and shoulder  420   b ). Again, the term concentric may be interpreted as referring to a relative size of shoulder  420   a  and shoulder  420   b  being larger than an outside diameter of pipe  305  while the term circumferential refers to the concentric shoulder  420   a  and shoulder  420   b  extending around a horizontal cross section of fitting  400  such that shoulder  420   a  and shoulder  420   b  acts as a stop for inserting fitting  400  into pipe  305 . 
     Fitting  400  may include a void  425 , which allows air to pass through first fitting  400  into pipe  305 . Void  425 , which is disposed within fitting  400 , may include threads  430 , which allow fitting  400  to attach to another pipe, an air compressor fitting, or a bladder fitting. 
       FIG. 5  illustrates a pressurized push rod system  500  for making a bladder based patch on an inside surface of a pipe  505 .  FIG. 5  illustrates a pressurized push rod system  500  in an environment that is similar to that shown in  FIG. 1 . As discussed in  FIG. 1 , pipe  505  has suffered a failure that requires repair, such as a crack or a hole developed from corrosion, or the like. For example, pipe  505  may be a conventional sewer pipe of any conventional diameter. Disposed within pipe  505  is a pressurized push rod device  510 , which is similar in implementation and description to pressurized push rod device  300 , shown in  FIG. 3 . As shown in  FIG. 5 , pressurized push rod device  300  is continuous without connection points, which is preferred. 
     However, it is possible that one or more connection points (not shown) may be necessary to connect one section of pressurized pushrod device  510  to another section of pressurized push rod device  510  to extend a length of pressurized push rod device  510 . Advantageously, however, sewer pipes in particular generally have a large enough interior diameter that any connections between pipes using the various fittings disclosed herein are durable to the point where they can withstand the stresses of working through, or being pushed past, pipe fittings, such as elbows, 45° bends, and other pipe fittings, without breaking. Further, since the piping used in pressurized push rod device  510  is relatively flexible while still being relatively rigid, the flexibility of the piping reduces the tensional stresses placed on connection points between different sections of pressurized push rod device  510 . 
     Pressurized push rod system  500  may include a fitting  515 , which may be similar in implementation and description to second fitting  350  shown in  FIG. 3  and fitting  400  shown in  FIG. 4 . As shown in  FIG. 5 , fitting  515  may be secured in place by a crimp  515   a , which is disposed between crimp retainer  415   a  and  415   b , shown in  FIG. 4  around an outside diameter of pressurized push rod device  510  to secure fitting  515  to pressurized push rod device  510  in an air tight manner. 
     Fitting  515  may connect directly to an air bladder fitting  525  or indirectly via an optional adapter  520 , depending on how an air bladder  530  is implemented. It is also conceivable that an air bladder  530  may be positioned at an end of pressurized push rod device  510  as an integral element of pressurized push rod device  510  (i.e., in place of or without air bladder fitting  525 ). In this example, air bladder  530  may include an air bladder fitting  525  which mates with fitting  515  or may require an adapter  520  to mate with fitting  515 . Air bladder  530  may be treated with a patch  535  for damaged portion of pipe  505 . 
     Pipe  505  includes a 90° bend  540 , which may also be referred to as an “elbow joint” in pipe  505 . Fittings such as 90° bend  540  are frequently used in plumbing applications and create substantial hardship in repairing a failure in a pipe. Pressurized push rod device  510  may be inserted in the X direction, as shown in  FIG. 5  up to the point of 90° bend  540 . Because of 90° bend  540 , pressurized push rod  510  is forced around 90° bend  540  to proceed in a Y direction within pipe  505 . Thus, in order to manipulate air bladder  530  to the point of the failure in the pipe, a user must push pressurized rod device  510  in an X direction in order to push air bladder  530  in the Y direction. Tensional stresses created by forcing pressurized push rod device  510  through 90° bend  540  are within tolerance specifications for pressurized push rod device  510 , even if a connection point between sections of pressurized push rod device  510  are disposed within 90° bend  540 , such that pressurized push rod  510  is undamaged and unharmed during traversal of 90° bend  540 . 
     Thus, a user may manipulate pressurized push rod device  510  to position air bladder  530  such that patch  535  may be applied to a failure in pipe  505 . Patch  535  may be any patch type known in the art. Exemplary patches may be fiberglass infused with epoxy resin and hardener, joint sealing compound, rubber, or any other type of patch material. Once patch  535  is positioned immediately proximate to the failure by pressurized push rod device  510 , an external air compressor may supply air into pressurized push rod device  510 . For example, a fitting, such as first fitting  310 , shown in  FIG. 3 , may connect to an air compressor to allow compressed air into a pipe, such as pipe  305  included in pressurized push rod device  510 . Compressed air may pass through pressurized push rod device into air bladder  530  such that both pressurized push rod device  510  and air bladder  530  are internally pressurized to substantially the same pressure (within 5 or less PSI). As air bladder  530  is inflated, air bladder  530  pushes patch  535  onto the failure and may be used to secure patch  535  in place, as necessary, as patch  535  cures. Air bladder  530  may also be treated with a release agent, which allows air bladder  530  to separate from patch  535  once patch  535  is cured and set. 
     Once patch  535  is sufficiently positioned and applied, a user may deflate air bladder  530  by allowing compressed air disposed within pressurized push rod device  510  and air bladder  530  to depressurize by simply disconnecting pressurized push rod device  510  from an air compressor. Once air bladder  530  is deflated, the user may withdraw pressurized push rod device  510  from pipe  505  without fear of pressurized push rod device breaking and without the use of a separate air line, as previously discussed with respect to  FIG. 1 , vastly improving the efficiency and user experience of applying a patch to a portion of a pipe which has failed. 
     The foregoing description is presented for purposes of illustration. It is not exhaustive and does not limit the invention to the precise forms or embodiments disclosed. Modifications and adaptations will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed embodiments. For example, components described herein may be removed and other components added without departing from the scope or spirit of the embodiments disclosed herein or the appended claims. 
     Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.