Patent Publication Number: US-2007107797-A1

Title: Machine for high speed weaving of chain link fence and process for making same

Description:
This application is based on Provisional Application Ser. No. US60/736,257 Titled APPARATUS FOR PRODUCING CHAIN LINK FENCING 
    
    
     BACKGROUND OF THE INVENTION  
      This invention relates generally to the field of manufacturing cyclone fence material and more specifically to a machine for high speed weaving of chain link fence and process for making same.  
      Chain link fence also known as cyclone fence has been made on semi automatic machines and automatic machines for over eighty years. These machines have evolved and now in the present day in America Bergandi Machine Company, California has set the standard.  
      While these machines have a loyal following, there are many ways that they can be improved.  
      The current operation of the Bergandi machines wastes a lot of time during the cutting and indexing cycle. The Bergandi machine, when making normal 2″ diamond fence×6 ft. wide fencing, cut index cycle time is 860 ms per cycle and repeats this approximately 9,630 times in an 8-hour shift.  
      My invention, using the pneumatic powered high speed finger and the pneumatic powered cut and index takes 180 ms to perform the cut and index cycle. Bergandi takes 860 ms to perform the cut index cycle. The difference=680 ms. 680 ms×9,630 cycles=1.819 hours less to complete the same number of cycles resulting in approximately a 25% increase in productivity.  
      With my invention, this 1.819 hours saved does not reflect the additional advantage of almost zero downtime due to wire jamming.  
      My invention incorporates jetted compressed air through an array of nozzles, which effectively eliminates friction and the lack of torque from the wire fed through the weaving tube.  
      Some of the problems of the prior technology are: 
          1. Extremely difficult to adjust. The average training time of a machine setter is three years of continuous day-to-day on-the-job learning.     2. The cutter, the index, and the edging devices are all driven from a common shaft.     3. Fine adjustments between the timing of the cut and index are not possible.     4. The machine maker claims that 1190 rpm is the maximum spindle (weaving) speed.     5. The weaving picket impinges on each loop as it threads (weaves) into the previous row which causes this picket to become slightly distorted on each successive revolution because the source of torque comes from the increasingly distant support of the weaving blade.     6. To overcome this distortion, the skill of the machine setter, in determining how much over-twist needs to be put into a blank picket, is a critical factor in determining the spindle speed of the machine in any given situation. 
 
 Once the machine is set and running at a stable speed, increasing the spindle speed has the effect of making the finished width narrower, and decreasing the spindle speed makes the finished width wider (less effect from friction). 
    7. The index mechanism is easily put out of alignment.     8. Coolant management is very poor and spills of toxic coolant are easily possible.     9. Operator safety is low. Manual controls can be operated with one hand, leaving the other hand free to occupy hazardous areas.     10. No patents have been filed by this company for productivity improvements for over 10 years.        

     BRIEF SUMMARY OF THE INVENTION  
      The primary object of the invention is to provide a fast and easy and user friendly and safe way to do the machine setup of chain link weaving machines.  
      Another object of the invention is to give the operator a standard way to set the machine for all widths of fence.  
      Another object of the invention is to make the manufacturing operation quicker than the prior art.  
      A further object of the invention is one way to make the operation quicker is to use the high speed finger.  
      Yet another object of the invention is to raise the weaving speed threshold. That is the speed of the weaving spindle.  
      Another object of the invention is to enable the weaving of wider fence fabric than was possible before.  
      Another object of the invention is novel ability to manufacture wide (over 500 feet) fabric.  
      Yet another object of the invention is fabric can be woven on site to stabilize steep slopes and earth dams.  
      Still yet another object of the invention is wire as thin as 16 Awg can now be woven reliably.  
      Another object of the invention is this ability to weave very thin wire would be a major cost savings.  
      A further object of the invention is this novel invention would allow the weaving of high strength plastic extrusions directly from the extruder.  
      Yet another object of the invention is where plastic monofilament fabric would open new markets for corrosion resistant fabric.  
      Still yet another object of the invention is to weave chain link substantially larger than the standard 2″ diamond of the present day.  
      Another object of the invention is to have ability to weave 4″, 6″, 8″, 10″ and larger size diamond.  
      Another object of the invention is to have the ability to weave any size diamond from present day standard maximum to over 24″.  
      Yet another object of the invention is to meet present day ISO 9001 quality standards with ease.  
      Still yet another object of the invention is to vastly reduce the quantity of scrap and waste during manufacturing and setup.  
      Another object of the invention is to reduce the quantity of environmentally hazardous liquids during manufacture.  
      In accordance with a preferred embodiment of the invention, there is disclosed a machine for high speed weaving of chain link fence comprising: Pneumatic powered high speed fingers are mounted on the weaving tube and holds the loose half of the picket in a very firm grip during the start of the next incoming picket, The processor controls the timing of the extension and retracting of the high speed fingers, A pair of pneumatic slides are mounted to the machine frame with cutting blades and bending forks for the rapid cutting of the finished picket, A pneumatic cylinder mounted to the frame actuates the indexing fingers, A weaving tube mounted to the frame has two axis of adjustment. This weaving tube is equipped with coupled sets of arrayed solenoid/nozzles and proximity sensors, The array of nozzles are coupled, so the torque exerted by the effect of the jets acting on each looped extremity of the picket is exerted on the opposite sides of each loop, which gives a smooth and balanced transfer of torque to the picket, The spindle is coupled to the encoder sending precise angular information at every instant to the processor, The processor controls all functions on the machine. The processor is mounted in an enclosure. The control panel allows the operator to make all normal adjustments for operation. The control panel alerts the operator of any abnormal condition, The sensors mounted on the weaving tube sense the precise angle of the picket and this angular information is fed into the processor. The processor controls the timing and the volume of the jets media issuing from the solenoid/nozzles, Manifolds on each half of the weaving tube supply pressurized media to the solenoid/nozzles, The solenoid control system is synchronized to the speed of the spindle, and The weaving tube is precisely made from solid low friction materials.  
      In accordance with a preferred embodiment of the invention, there is disclosed a process for high speed weaving of chain link fence comprising the steps of: Pneumatic powered high speed fingers are mounted on the weaving tube and holds the loose half of the picket in a very firm grip during the start of the next incoming picket, The processor controls the timing of the extension and retracting of the high speed fingers, A pair of pneumatic slides are mounted to the machine frame with cutting blades and bending forks for the rapid cutting of the finished picket, A pneumatic cylinder mounted to the frame actuates the indexing fingers, A weaving tube mounted to the frame has two axis of adjustment. This weaving tube is equipped with coupled sets of arrayed solenoid/nozzles and proximity sensors, The array of nozzles are coupled, so the torque exerted by the effect of the jets acting on each looped extremity of the picket is exerted on the opposite sides of each loop, which gives a smooth and balanced transfer of torque to the picket, The spindle is coupled to the encoder sending precise angular information at every instant to the processor, The processor controls all functions on the machine. The processor is mounted in an enclosure. The control panel allows the operator to make all normal adjustments for operation. The control panel alerts the operator of any abnormal condition, The sensors mounted on the weaving tube sense the precise angle of the picket and this angular information is fed into the processor. The processor controls the timing and the volume of the jets media issuing from the solenoid/nozzles, Manifolds on each half of the weaving tube supply pressurized media to the solenoid/nozzles, The solenoid control system is synchronized to the speed of the spindle, and The weaving tube is precisely made from solid low friction materials.  
      Other objects and advantages will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL DRAWINGS  
      The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.  
       FIG. 1  is a perspective view of the invention as seen from the rear or looking toward the operation side of the machine.  
       FIG. 2  is a perspective view of the invention as seen from above from the operator&#39;s side.  
       FIG. 3  is a perspective view of the prior art as seen from above from the operator&#39;s side.  
       FIG. 4  is a close up view of the invention from the operator&#39;s side.  
       FIG. 5  is a close up view of the weaving tube entrance.  
       FIG. 6  shows the same view as  FIG. 5  shifted slightly to the left to show the detail of the high speed finger.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Detailed descriptions of the preferred embodiments are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Various aspects of the invention may be inverted, or changed in reference to specific part shape and detail, part location, or part composition. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner.  
       FIG. 1  is a perspective view of the invention as seen from the rear or looking toward the operation side of the machine. The high speed finger  101 , enters slot  102  where it engages picket  103 . The finger which is mounted on swivel  104 , is fixed to pneumatic slide  105 , and the fixed portion of the slide is mounted to the weaving tube  106 . The weaving tube  106  is mounted to the frame by means of a two-axis adjustment. The cutters  107  and  108  cut the picket when the spindle stops. The indexing fingers  116  hold the stationary picket  109 .  
      The index mechanics  111 - 116  are of prior art and is shown for completeness of understanding. The index cylinder  111  is mounted to the frame and transmits thrust through clevis  112 . The bearings  113  hold the pivot shaft  114 , and adjustable clamps  115  hold adjustable index fingers  116 . Square bar  117  eliminates any twisting in the assembly.  
       FIG. 2  is a perspective view of the invention as seen from above from the operator&#39;s side. Rear cutter slide  201  is fixed to the frame. The rear cutter blade mount  202 , rear blade  203 , rear bending fork  204  all move together. The front bending fork  206 , front cutter blade  207 , front blade mount  208  move together. The front slide  209  is fixed to the frame. Both cutter slides have built-in hydraulic shock absorbers  210 . The view further shows the position of the high speed finger  211 . The slide  212  is mounted to the weaving tube. The index cylinder  213  moves the index fingers  214  and  215 . The index fingers  214  and  215  hold the stationary picket  205 .  
       FIG. 3  is a perspective view of the prior art as seen from above from the operator&#39;s side. Cutter slide  305  and  306  are mechanically driven by a crank.  FIG. 3  shows the cutters  303  and  304  in the open position. The cutters  303  and  304  and bending forks  301  and  302  are mounted on the slides  305  and  306 . Low speed finger  307  is mounted on spring-loaded pivot  312 . Its path is controlled by cam  308  riding on adjustable guide  311 . The front hinged half of the weaving tube  309  and the rear half of the weaving tube  310  are shown holding stationary picket  313 .  
       FIG. 4  is a close up view of the invention from the operator&#39;s side. The weaving tube  401  shows the helical path that the picket  412  travels on the inside of the weaving tube while it weaves into the loose half of the stationary picket  413 . When the picket loops of  412  pass the array associated with solenoid/nozzles  402 ,  403 ,  404  the picket is given impetus from the ejected media. The proximity sensors  405  and  406  senses its position and passes this angular information to the processor. The picket loop is then pushed around to solenoid/nozzle  407 ,  408 ,  409  by means of high pressure media being ejected through solenoid/nozzle  402 ,  403 , and  404 . Then the processor turns on the array associated with solenoid/nozzles  407 ,  408 , and  409  and proximity sensors pick up the positional information of the picket. Solenoid/nozzle  402 ,  403 , and  404  switch off, then the process repeats continuously around the circumference of the weaving tube until the picket is at its predetermined length.  
       FIG. 5  is a close up view of the weaving tube entrance. The manifold  501  (red end) and manifold  507  (red end) feed the solenoid/nozzle units arrays ( 502  and  508 ). These two arrays start ejecting pressurized media to simultaneously to supply torque to the picket. After the picket revolves 60 degrees in the weaving tube, the next pair of arrayed nozzles ( 504  and  510 ) line up and they start ejecting pressurized media, propelling the picket to the next array ( 506  and  512 ), and so on.  
      The manifold  501 , supplies array  502 , which is electrically coupled to array  508  and then manifold  507  supplies pressurized media to array  508 . The manifold  503 , supplies array  504 , which is electrically coupled to array  510  and then manifold  509  supplies pressurized media to array  510 . The manifold  505 , supplies array  506 , which is electrically coupled to array  512  and then manifold  511  supplies pressurized media to array  512 . Only one pair of coupled arrays eject pressurized media at any given time throughout the process.  
       FIG. 6  shows the same view as  FIG. 5  shifted slightly to the left to show the detail of the high speed finger. The front half of the weaving tube  601 , is off set from the rear half  602 , slightly at the hinge so the picket revolving in the tube will not catch on the join. This slot  603  is the drain for weaving coolant, and helps relieve the internal pressure from the nozzles. The front half of the weaving tube is hinged at the slot  603 , and opens to allow blank pickets to be removed during setup. This is a clear view of the high speed finger  605  engaging the third loop in the loose half of the picket  606 . The pneumatic slide  607  provides motion through the pivot  608 . A spring attached to  609  provides adjustable down force for the high speed finger  605  to firmly grip the loose half of the picket through the first two revolutions of the weaving process. The high speed finger then retracts to clear the path of the incoming picket. The loose half is now stabilized by the weaving process.  610  is the adjustable down stop for the high speed finger.  
      Describing what is the old method of chain link manufacturing, refer to  FIG. 3  where we see the general layout of the cutting and holding of the loose half of the picket.  FIG. 3  shows the cutters  303  and  304  in the open position. The cutters  303  and  304  and bending forks  301  and  302  are mounted on the slides  305  and  306 . The slides are mechanically operated. When the cutters are closed, the tip of the low speed finger  307  engages in the loose half of the picket  313 . During the index cycle, the tip of the finger  307  engages momentarily and is extremely difficult to adjust because of the very short period of time that it holds picket  313  before retracting, due to the fact that it is mounted on the slide  305 . The problems associated with the finger  307  are as follows: If not adjusted correctly, it can cause the loose half of the picket to flip over a half or a full revolution which causes edge flaws and/or a wire jam. Adjusting the cam  311  and the spring tension in the pivot  312  on the cam  308  takes a very high level of expertise. Correct adjustments can take many minutes to do and many blank pickets are scrapped during this process. Improper adjustments lead to wire jams and/or edge defects. The wire jam sensor has a latent defect in that it senses a jam and stops the weaving blade only after 6-12 feet of wire have been forced into a 1 foot ball of twisted and compacted steel, which has to be cut through and cleared by the operator. Clearing wire jams takes approximately 5-10 minutes. Cumulatively, this defect is responsible for hours of lost production and much scrapped material.  
      Further describing the operation of what is old, the cutters mounted on the slides are mechanically operated by a common shaft. The shaft has cams that drive the cutter, the index mechanism, and the edging tools. The timing relationship between these functions is fixed and has been fixed to enable the thickest and most difficult size of wire specified to be woven by that particular machine. The fixed timing relationship between the function of cutting and indexing and the fact that the low speed finger  307  is mounted on the slide  305  contribute to lost time. The average time taken to cut and index is 850 milliseconds per picket woven.  
      The inside of the weaving tube  309  (hinged front half) and  310  (rear half) is smooth and serves only to guide the picket being woven. The weaving tube is hinged to allow the operator to remove blank pickets run into the tube during setup. Running blank pickets into the weaving tube allows the operator to adjust the over-twist needed. Over-twist is needed to counteract the successive reduction of twist and length due to friction (untwisting), so when the picket is woven into the fence, the picket is at a neutral plane and at the correct length. The operator at set up runs a picket into the tube at the set speed without engaging in any previous picket. He then uses his experience to gauge how much over-twist and over-length is required. For every slight adjustment, a blank picket is scrapped. Before each setup and after each wire jam, blank pickets need to be made resulting in much scrap metal. In a normal work day, many jams occur. Due to the fact that set up is very difficult, manufacturers tend to over produce when the machines are running smoothly, which results in increased inventory and the costs associated with the excess inventory.  
      The maximum weaving speed claimed today is approximately 1,190 rpm and the maximum width is 25 feet (reference Bergandi Machinery Company, California). To avoid frequent wire jams, the typical maximum operating speed is 950 rpm, and in many cases weaving speeds of 700 rpm are regularly used to ensure consistent production. Even at the lower speeds, wire jams are inevitable.  
      Here is what is new. The cutters are mounted to a pair of pneumatic slides that are mounted to the frame of the machine with cutting blades and bending forks for rapid cutting of the finished picket. A pneumatic cylinder mounted to the frame actuates the indexing fingers. The weaving tube is mounted to the frame with two axis of adjustment. This weaving tube is equipped with coupled sets of arrayed solenoid/nozzles and proximity sensors. The array of solenoid/nozzles are coupled,  FIG. 5   502  and  508 ,  504  and  510 , and  506  and  512 , so the torque exerted by the effect of the jets on each looped extremity of the picket is exerted on the opposite sides of each loop, which gives a smooth and balanced transfer of torque to the picket. Alternatively, a high speed digital camera or laser sensors aimed at the end of the weaving tube may replace the proximity sensors. The cutters, the high speed finger, and the index mechanism are all pneumatically powered and the operator can finely tune the timing relationships between these three actions on the control panel. The high speed finger has been removed from the slide  FIG. 3, 305  and placed in its new position on the pneumatic slide,  FIG. 1   105 .  
      Referring to  FIG. 1 , the pneumatic powered high speed finger  101  enters the rear half of the weaving tube  106  through slot  102  and engages the loose half of the picket on the third loop  103 . The high speed finger holds the loose half of the picket in a very firm grip during the start of the next incoming picket  103  completes 2 full revolutions in the completed picket  109 . At this point, the processor signals for the instant retraction of the high speed finger to clear the path for the incoming picket. The loose half of the picket at this point is held stable by the first 2 full revolutions woven, and this innovation has proven to eliminate the loose half of the picket flipping. Wire jams due to high speed finger malfunction, by experience, did not occur in 7 days of continuous 8 hours a day production. The average time taken to cut and index with the high speed finger  FIG. 1   101  is 180 milliseconds per picket woven. The time saved with the machine equipped as described above enabled an extra 1,000 feet of 6 foot wire to be manufactured in an 8-hour shift resulting in virtually no scrap material.  
      Because over-twist is needed to counteract the successive reduction of twist and length due to friction (untwisting), what is old has limitations of speed and maximum width that can be manufactured (950 rpm and 25 feet, respectively). This invention eliminates and counteracts the inherent friction experienced in the weaving process. The previous limitations of speed have been raised to 2,000 rpm and the previous limitation of width has yet to be determined. (It is envisioned that widths of 1,000 feet are possible.)  
      How this innovation works is described as follows: In the preferred method, compressed air is led into manifolds which feed an array of coupled solenoid/nozzles which blow timed pulses of compressed air onto the loops of the picket in motion in phased sequence. Only one pair of coupled arrays eject pressurized media at any given time throughout the process. These pulses of compressed air supply the exact amount of torque required to counteract the inherent friction that occurs as the picket travels through the weaving tube and the loops of the stationary picket. This arrangement allows for speeds of weaving over 2,000 rpm. This high speed would result in more than doubling present day production output. In addition, wire jams would virtually be eliminated. Because adjustments for over-twist and over-length would not be necessary, machine setting would be greatly simplified. Alternatively, in place of compressed air, any media, gaseous or liquid or steam may be used to supply torque to the picket being woven. In addition, an array of magnets may be used to pull the picket in its helical path through the weaving tube.  
      Referring to  FIG. 4 , manifolds  408  and  409  feed solenoid/nozzles  402  and  403 , which supply torque to picket  410  which weaves through tube  401  and engages in stationary picket  411 . The proximity sensors  406  and  407  are mounted on the weaving tube  401  sense the precise angle of rotation of picket  410  and transmits this angular information to the central processor. In the block diagram,  FIG. 7 , the central processor  701 , gets information from spindle encoder  702  mounted on the weaving blade. The processor mounted in an enclosure compares the angular information from the encoder  702  to the angular information from the sensor array  703  and adjusts the output and the timing to the solenoid/nozzle array  704  which controls the timing and the volume of the jets of media issuing from the solenoid/nozzles. This control loop ensures 2 things: 1) it keeps the picket in perfect synchronization with the weaving blade, and 2) it shuts down the spindle drive instantly and alerts the operator via the control panel of any abnormal condition, for example where the jam is located. This feature eliminates the 6-12 foot ball of wire that would normally accumulate with a wire jam at the weaving tube entrance. The net result would be wire jams consisting of only 2-3 inches of scrap wire, saving operator time and material cost.  
      Alternatively, many nozzles may be supplied by one solenoid in the array system. Alternatively, many nozzles may be triggered pneumatically. Alternatively, valve/nozzles may be pneumatically operated. Alternatively, valve/nozzles may be motorized in synchronization with the weaving speed. Alternatively, valve/nozzles may be hydraulically operated. Alternatively the pneumatic powered indexer, electric motors, hydraulic cylinders, electromechanical devices or any other means of power to achieve the end result may power cutter and high speed finger.  
      The frame is built on almost the same lines as what are commonly available from local manufacturers. The innovations are the items in the drawings as shown in  FIGS. 1, 2 ,  4 ,  5  and  6 . Two pneumatic slides are off the shelf items to which are bolted the cutter holders and the bending forks.  
      The weaving tube is machined from solid low friction material, and must be perfectly round in the weaving section. Arrays of precisely angled holes are drilled to coincide exactly with the helical path the picket loops take for each particular size of fabric to be woven. The arrays of solenoid/nozzles may be arranged in two pole, four pole, six pole, eight pole, or any number of poles, space permitting, depending on the diameter of the weaving tube. In the preferred embodiment of 2″ diamond fabric, three coupled arrays of solenoid/nozzles and three arrays of proximity sensors would be used. Then the proximity sensors are installed as per  FIG. 4 . Note: sensors are installed on one half of the tube—front is preferred. In the case where 4″ diamonds are required the weaving tube would have six coupled arrays. In the preferred embodiment, the distance from the nozzle to the loop of the picket should be approximately 1″ before the next array of nozzles apply torque. Compressed air is the preferred embodiment for the type of media ejected from the nozzles. Steam has certain applications, as does high pressure water. Each type of media has benefits and drawbacks. Clearly when liquid is used, environmental issues follow. After deciding on the type of media to be ejected form the nozzles, the correct plumbing is installed and pressure source chosen. Plumb all the arrays and wire up the solenoids to the controller.  
      The servo driven for the spindle would be more powerful than prior art to enable high acceleration and braking. The tools for performing the edges need to be changed to enable this increase in performance.  
      The control program is of normal common PLC processor variety as are all components such as nozzles, nozzle—solenoid combinations, pipe fittings, air cylinders and hydraulic dampers are all off-the-shelf items. Special items are the weaving blade replacing the prior art. This needs to be made from ultra-hard steel with as much stiffness as possible. This item is not adjustable as in the prior art. This is one more advantage—no tedious adding or subtracting twist to the weaving blade in the machine setting process.  
      The preferred method of powering the finger is pneumatic. It may be powered by any other known method to produce the same result.  
      The preferred position of the finger is on the third loop of the picket measured from the spindle but may be in any loop in the picket.  
      The finger in very wide machines may have more than one and may have as many as fifty fingers.  
      In the system of nozzles, the preferred media is compressed air but may include any gas or any liquid at any temperature, including steam.  
      In the system of nozzles, the shape of the ejected spray is to include any pattern.  
      In the system of nozzles, the angle of the nozzle relative to the helical path of the wire being woven may be adjusted on the fly as need be.  
      The nozzles may have the ability to be strictly on-off, or to have the ability to modulate the flow from zero to full on in a very fast manner.  
      The control system switching the nozzles and the resulting ejecta may modulate the volume of ejecta and period of ejecta as need be.  
      The control system receives a feedback signal from sensors mounted on the weaving tube or from a camera or from an array of laser sensors measuring the angle of the picket relative to the spindle.  
      The difference in the amount of angular deviation between the picket and the spindle is measured, and this difference is fed back to the control loop.  
      The nozzles power the picket and the picket is kept in perfect synchronization with the spindle by modulating the pressure or the time or the volume of delivery through the solenoids.  
      The diameter of the weaving tube may be adjustable.  
      The arrays of nozzles may be arranged in two pole, four pole, six pole, eight pole, or any number of poles—space permitting.  
      The arrays of nozzles may be replaced with electromagnets that would be mounted in a non-magnetic weaving tube.  
      The electromagnets would be arranged to pull the outermost loops of the steel picket and provide the required torque to the picket.  
      Where liquid media is used, a collection system using vacuum to recycle the liquid may be used.  
      The weaving tube may be ventilated in the most advantageous manner to enable the pressure in the weaving tube to be as low as possible.  
      The weaving tube may have a system of forced extraction of jetted media  
      While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.