Patent Publication Number: US-6654998-B1

Title: Method of installing plates on blade of plow or grader

Description:
RELATED APPLICATIONS 
     This is a Divisional application of application Ser. No. 09/248,586 filed Feb. 11, 1999 now U.S. Pat. No. 6,241,227 issued Jun. 5, 2001. 
    
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to accessories used with plows (e.g., snow plows) and graders. More particularly, the present invention concerns a device for handling replaceable plates, such as cutting edges and wear plates, used on the blades of plows and graders. The present invention also concerns the improved method of installing the replaceable plates. 
     2. Discussion of Prior Art 
     The blade of a plow or grader is typically provided with at least one replaceable plate for improving the cutting and/or plowing action of the blade and for increasing the life span of the blade. It is common to utilize a dual plate arrangement, which often includes a cutting edge secured against the lower margin of the front face of the blade and a wear plate secured over the cutting edge. The cutting edge projects downwardly below the lower margin of the blade and is customarily formed of a hard material, such as tungsten carbide. The wear plate is designed to cooperate with the cutting edge in improving blade operation and durability. Particularly, the wear plate and cutting edge are preferably coextensive, with the wear plate being superimposed over the cutting edge. The wear plate is preferably formed of a stronger, more durable material (e.g., standard carbon steel) than the cutting edge. That is to say, the cutting edge is typically formed of a brittle albeit hard material, and the wear plate is consequently designed to absorb the impact loads created as the blade encounters objects, such as rocks or other debris located on a roadway. 
     It will be appreciated that replacement plates extend across the entire blade and are consequently relatively long, even when divided into several sections arranged end-to-end across the front of the blade. For example, a typical plow blade and the replacement plates used thereon will be approximately twelve feet long (measured from side to side). The plates are consequently unwieldy and heavy. Moreover, replacement of the plates traditionally involves two workers manually holding the plate off of the ground and moving the plate until the attachment holes in the plate align with the corresponding attachment holes defined in the blade, while a third worker inserts bolts through the aligned attachment holes. It will also be appreciated that conventional replacement plates will often weigh in excess of one hundred pounds. Thus, the conventional system for replacing the plates used on the blade of a grader or plow is laborious, difficult and expensive. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Responsive to these and other problems, an important object of the present invention is to provide a system for simplifying and facilitating the replacement of the plates used on the blade of a plow or grader. It is also important object of the present invention to provide a device for assisting the worker with manipulation of the plates during installation and removal. Another important object of the present invention is to make the device inexpensive and simple in construction, yet sufficiently durable to withstand the rigorous operating conditions encountered during blade replacement. Yet another object of the present invention is to provide a system that permits the plates to be replaced by only one worker, without requiring the worker to manually hold the plates off of the ground during replacement. 
     In accordance with these and other objects evident from the following description of the preferred embodiment, the present invention concerns a device in the form of a cart for handling the replaceable plates used on the blade of a plow or grader. The cart includes a wheeled frame and a plate holder supported on the frame for up and down movement relative to the ground. The plate holder is designed to support the plate in an orientation generally corresponding to the front face of the blade. This typically involves supporting the plate in an upright orientation so that the plate may be placed against the generally upright front face of the blade. In some cases, the plate may be oriented at a slight angle relative to vertical to correspond with the orientation and/or the curvature of the front face of the blade. 
     The cart preferably includes a parallelogram linkage for supporting the plate holder on the frame, with the linkage maintaining the plate holder, and thereby the plate or plates supported thereon, in a single orientation as the holder is raised and lowered. An actuator may be connected between the frame and linkage for effecting raising and lowering of the plate holder. This is particularly useful when the cart is being used to install large, heavy plates. The cart may also be provided with a tongue that facilitates movement of the cart into the desired locations, especially in low clearance situations. The frame of the cart is preferably supported on caster wheel assemblies, and the tongue may be attached to the frame in several different locations to improve maneuverability of the cart. 
     The present invention also concerns the improved method of installing the replaceable plates. This method permits just one worker to install the plates, without having to manually hoist the plates during installation. Particularly, the installation method involves the steps of supporting at least one plate on a mobile cart and aligning the attachment holes defined in the at least one plate with the corresponding attachment holes defined in the blade. The plate is preferably supported on a height-adjustable holder carried on the frame so that the height of the plate may be adjusted during the step of aligning the attachment holes. Of course, alignment of the attachment holes may also involve moving the cart into proximity with the blade. 
    
    
     Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures. 
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     Preferred embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein: 
     FIG. 1 is a perspective view of a cart constructed in accordance with the principles of the present invention, with the illustrated cart supporting a replaceable plate as it is being installed on the blade of a plow or grader; 
     FIG. 2 is an enlarged top plan view of the cart shown in FIG. 1; 
     FIG. 3 is an enlarged side elevational view of the cart shown in FIG. 1 with parts being partly broken away to show the constructional details of the actuator, and particularly illustrating the cart being used to install the second replaceable plate (typically referred to as the wear plate) on the front blade of a plow or grader. 
     FIG. 4 is an enlarged side elevational view of the cart shown in FIG. 1, particularly illustrating the cart being used to install a replaceable plate on a relatively low blade, such as an underbody plow or grader; 
     FIG. 5 is a fragmentary perspective view of an alternative embodiment of the present invention, wherein an extension boom having a pair of clamping mechanisms is provided for securely supporting a long plate and/or a plurality of plate sections; and 
     FIG. 6 is a enlarged vertical cross-sectional view of the alternative embodiment, particularly illustrating a pair of replaceable plates supported on the extension boom as they are being installed on the blade of a plow or grader. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning first to FIG. 1, the plate handling device  10  selected for illustration comprises a mobile cart designed to assist the operator in installing and removing the replaceable plates used on the blade of a plow or grader. As will subsequently be described, the illustrated cart  10  permits a single user to install a plate, without having to hold the plate off the ground during installation. That is to say, the illustrated cart  10  permits the user to relatively effortlessly manipulate a plate into the proper orientation with respect to the blade. It is particularly noted that the cart  10  generally includes a wheeled frame  12 , a tongue  14  projecting from the frame  12 , a pair of plate holders  16  and  18 , a parallelogram linkage  20  supporting the plate holders  16  and  18  on the frame for relative up and down movement an actuator  22  coupled between the frame  12  and linkage  20  for controlling the height of the holders  16  and  18 , and various other parts associated with these primary components. 
     The wheeled frame  12  has a relatively low profile (e.g., see FIG. 4) and preferably includes a pair of fore-and-aft extending U-shaped beams  24  and  26  and a pair of flat, transverse cross-plates  28  and  30  (e.g., see FIGS. 1 and 2) interconnecting the beams  24  and  26 . It is noted that each of the plates  28  and  30  is fixed to the top of the beams  24  and  26  at a corresponding end thereof. In addition, each of the plates  28  and  30  has sufficient length to project laterally outward of the beams  24  and  26  to present overhanging portions. The illustrated frame  12  further includes four caster wheel assemblies  32 , 34 , 36 , 38  connected to the overhanging portions of the plates  28  and  30 . Only the caster wheel assembly  34  will be detailedly described herein, with the understanding that the remaining wheel assemblies are similarly constructed. The assembly  34  includes a wheel  40  rotatably supported between the arms of a yoke  42 . The assembly  34  further includes a threaded fastener  44  for attaching the assembly to the corresponding overhanging portion of the cross-plate  28 , with a traditional swivel (not shown) being provided between the yoke  42  and fastener  44  for allowing the yoke  42  to rotate about an upright axis generally defined by the fastener  44 . Those ordinarily skilled in the art will appreciate that the caster wheel assemblies  32 - 38  permit the cart  10  to be moved in virtually any direction across the support surface. In addition, it is not necessary that the cart  10  be equipped with four caster wheels assemblies to provide the desired multidirectional movement (e.g., two caster wheel assemblies and two fixed wheel assemblies may be sufficient). 
     Projecting from one end of the frame  12  is a tongue attachment bracket  46 , which includes a pair of spaced apart, rectangular shaped plates  48  and  50  fixed to the underside of the cross-plate  28 . The plates  48  and  50  present aligned openings (not visible in the drawing figures) configured to receive a retaining pin  52  therein. 
     In this respect the illustrated tongue  14  includes a square-shaped tube  54  having an opening (also not visible in the drawing figures) adjacent one end thereof, with the opening similarly being configured to receive the retaining pin  52  therein. The tube  54  is consequently swingable about a substantially horizontal axis defined by the pin  52 . A cylindrical rod  56  is preferably fixed to the distal end of the tube  54  for presenting a handle that may be grasped by the user during manipulation of the cart  10 . 
     A second tongue attachment bracket  58  is provided on the side of the frame  12 . The side bracket  58  similarly includes a pair of plates  60  and  62 , although the plates  60 , 62  are fixed to the outer side of the beam  26 . The plates  60  and  62  present aligned openings  64  and  66  configured to receive the retaining pin  52 . Accordingly, the tongue  14  may be connected to the frame  12  by either bracket  46  or  58 , with movement of the tongue  14  from one bracket to another simply requiring removal of the pin  52 , alignment of the openings in the tongue and other bracket, and insertion of the pin  52  into the aligned openings. It is noted that the tongue  14  projects in relatively transverse directions when attached to the brackets  46  and  58 . 
     The frame  12  and tongue  14  are preferably formed of metal, although other suitable materials (e.g., high strength plastic) may be used. In addition, the means by which components of the frame  12  and tongue  14  are fixed to one another may be varied as desired, although suitable welding techniques are preferred. 
     The parallelogram linkage  20  includes two equal-length bars  68  and  70  (e.g., see FIG.  3 ), each of which comprises a respective pair of laterally spaced apart links  68   a , 68   b  and  70   a , 70   b . The links  68   a  and  70   a  are pivotally connected to the beam  24  by respective fasteners  72  and  74  (e.g., standard nut and bolt assemblies), and the links  68   b  and  70   b  are similarly connected to the beam  26  by fasteners  76  and  78  (e.g., see FIG.  2 ). The pivot connections for the links  68   a , 68   b  or  70   a , 70   b  of each bar  68  or  70  are aligned. Each of the links  68   a , 68   b , 70   a , 70   b  is preferably formed of a square-shaped metal tube, although any suitable material may be used. It is noted that the links  68   a  and  68   b  are interconnected by a brace  80 , with the brace being preferably welded between the links when these components are formed of metal. Although not shown, a similar brace may be fixed between the links  70   a  and  70   b  if desired. 
     A pair of U-shaped connectors  82  and  84  extend between and serve to connect the upper ends of the links  68   a , 70   a  and  68   b , 70   b , respectively. If desired the connectors  82  and  84  may be formed of the same material as the beams  24  and  26 . Similar to the opposite ends of the links, fasteners  86 , 88 , 90 , 92  (see FIGS. 1 and 3) are provided to pivotally attach the links to corresponding ones of the connectors  82  and  84 . In addition, the upper pivot connections for the links  68   a , 68   b  or  70   a , 70   b  of each bar  68  or  70  are aligned. Because of the parallel arrangement of the linkage  20 , the upper pivot connections for the links  68   a  and  70   a  are spaced apart the same distance as the lower pivot connections, and the same may be said of the pivot connections for the links  68   b  and  70   b . The plate holders  16 , 18  are fixed to one end of the connectors  82 , 84 , whereby the linkage  20  supports the holders  16 , 18  on the frame  12  for relative up and down movement. 
     The linkage  20  is attached is coupled to the frame  12  closer to one end of the beams  24 , 26  than the other and is generally disposed over the frame  12 . Thus, movement of the linkage  20  is generally limited to the area above the frame  12 , although the linkage  20  may be folded down to an orientation relatively close to the ground as a result of the low profile of the frame  12  (e.g., see FIG.  4 ). However, it will be appreciated that the principals of the present invention are equally applicable to various other frame and linkage arrangements. For example, the device may include a relatively taller frame with the parallelogram linkage projecting from one of the ends or sides of the frame to support the plate holder(s) thereon. In any case, it is preferred that the device be configured so that the plate holder(s) be positionable relatively close to the ground. 
     Movement of the linkage  20 , and thereby adjustment of the height of the plate holders  16  and  18 , is controlled by the actuator  22 . In the illustrated embodiment, the actuator  22  comprises a hand-operated hydraulic piston and cylinder assembly including a cylinder  94  housing the piston (not shown) and a rod  96  telescopically received within the cylinder  94  and attached to the piston. This type of assembly is often referred to as a “bottle jack”, although any suitable actuator (e.g., a ratchet-type lift) may be used. In the usual manner, the jack  22  includes a pedestal  98 , from which the cylinder  94  projects, and a crank mechanism  100  that controls extension of the rod  96  relative to the cylinder  94 . The mechanism  100  also includes a removable arm  102  and a release screw (not shown) that permits retraction of the rod  96  when activated. As is also customary, a screw  103  is threadably connected to the distal end of the rod  96 . 
     The jack  22  is pivotally coupled to the frame  12  by a pivot assembly  104 , as perhaps best shown in FIGS. 1 and 3. The assembly  104  includes a cylindrical rod  106  fixed between the beams  24  and  26 , a sleeve  108  slidably received on the rod  106 , and a mounting plate  110  bolted to the underside of the pedestal  98  and secured to the sleeve  108  in a tangential relationship. The opposite end of the jack  22  is attached to an arm  112  that serves to couple the former with the linkage  20 . The illustrated arm  112  includes a pair of side plates  114  and  116  pivotally attached to respective ones of the links  68   a  and  68   b  by fasteners  118  and  120  (e.g., see FIGS.  1  and  2 ). A square-shaped metal tube  122  is preferably welded between the side plates  114  and  116 , with the tube  122  presenting an opening  124  (see FIG. 3) configured to receive the screw  103  therein. An opening  125  (see FIGS. 1 and 2) is also defined in the tube  122  for receiving the crank arm  102  therein during periods of non-use (e.g., see FIG.  4 ). 
     Extension of the rod  96  relative to the cylinder  94  causes the linkage  20  to unfold and thereby raise the plate holders  16  and  18 . It is noted that FIG. 3 illustrates the rod  96  in the fully extended condition and the holders  16  and  18  in the fully raised position. On the other hand, when the rod  96  is retracted, the linkage  20  folds and the plate holders  16  and  18  are consequently lowered. The fully lowered positions of the holders  16  and  18  is illustrated in FIG.  4 . The parallelogram linkage  20  insures that the orientation of the plate holders  16  and  18  remains substantially constant as it is raised and lowered. 
     Turning now to the preferred construction of the holders  16  and  18 , the plate holder  16  comprises an L-shaped element presenting a generally upright wall  126  and a transverse wall , 130 . It is noted that the holder  16  is disposed at a slight angle relative to horizontal so that the wall  130  slopes downwardly toward the upright wall  126  (see FIGS.  3  and  4 ). This is preferably accomplished by tapering the upper edge of the connectors  82  and  84  adjacent the corresponding end (e.g., by grinding, cutting, etc.) and then fixing the wall  128  to the tapered end of the connectors  82  and  84 . The plate holder  16  is preferably formed of the same material as the connectors  82  and  84 . Particularly, the preferred holder  16  is formed of standard angle iron and is welded to the connectors  82  and  84 . 
     The wall  128  defines an upwardly facing support surface having sufficient length to support the replaceable plates thereon. As will be described further below, the upright wall  126  serves to support the replaceable plates in an upright orientation when they are supported on the wall  128 . A nut and bolt assembly  130  is attached to the wall  128  at a location spaced from the upright wall  126  to define a projection that assists with retaining the replaceable plates in the upright orientation. Those ordinarily skilled in the art will appreciate, however, that the projection may be variously constructed (e.g., the projection may be formed by a block-welded to the upper surface of the wall  128 ). It is also noted that the angled orientation of the support  16  further assists with retaining the plates in the upright orientation. 
     The plate holder  18  similarly comprises a pair of generally L-shaped elements projecting forwardly from the connectors  82  and  84 , respectively, and cooperatively presenting a generally upright wall  132  and a bottom support wall  134 . It is noted, however, that the walls  132  and  134  of the holder  18  are not transverse relative to one another. Instead, the upright wall  132  is disposed at an obtuse angle (e.g., 120°) relative to the generally horizontal wall  134 . One of the replaceable plates may consequently be placed on the support wall  134  and supported in a generally upright orientation by the wall  132 . The ends of the connectors  82  and  84  serve to retain the plates supported on the wall  134  in the generally upright orientation. This is facilitated by the angle of the wall  132  relative to the wall  134 . 
     In view of the foregoing, it will be appreciated that the cart  10  may be used to facilitate replacement of virtually any type of plate used on the blade of a plow or grader. In addition, the cart  10  can be used during replacement of plates on various types of blades. For example, a snow plow will often include a front blade supported ahead of the vehicle, a side-mounted wing blade supported alongside the vehicle, and/or an underbody blade mounted under the vehicle between the front and rear wheels. For purposes of illustration, FIGS. 1-3 depict installation of a cutting edge  136  and a wear plate  138  to a front blade  140 , while FIG. 5 illustrates installation of the cutting edge  136  to an underbody blade  142 . 
     Turning first to FIGS. 1-3, the cutting edge  136  is preferably placed in an upright orientation on the wall  128  between the projection  130  and the upright wall  126 . The cutting edge  136  may be placed on the support wall  128  when the linkage  20  is folded so that the holder  16  is in its lowermost position, thereby reducing the amount the edge  136  must be lifted by the worker. In fact, only one end of the edge  136  need be lifted onto the support  16  and then the edge  136  may be slid lengthwise toward the propped-up end until the center of gravity of the edge  136  is securely positioned over the holder  16 . The actuator  22  is then operated by cranking the arm  102  so that the rod  86  extends to raise the holder  16 . Once the edge  136  is in general vertical alignment with the lower boundary of the blade  140 , the cart  10  is preferably moved into proximity with the blade  140  until the edge  136  contacts the front face of the blade  140 . Such movement of the cart  10  is, of course, facilitated by the tongue  14 . The plate holder  16  is further raised and lowered and the cart  10  may be further moved so that the attachment holes  144  defined in the edge  136  are brought into alignment with the corresponding attachment holes  146  defined in the blade  140 . Bolts  148  are preferably then inserted through the aligned attachment holes  144  and  146 . If desired, the bolts  148  may be inserted before or as the holes  144  and  146  are aligned to facilitate such alignment. In addition, pins (not shown) may be inserted into one or more of the holes  144  or  146  defined in the edge  136  or blade  140  to facilitate such alignment. As perhaps best shown in FIG. 3, the holder  16  is preferably arranged so that the orientation of the plate supported on the holder  16  (the wear plate  138  in the case of FIG. 3) generally corresponds to that of the front blade  140 , which further facilitates alignment of the attachment holes  144  and  146 . It is also noted that the upright wall  126  is dimensioned so that it does not get caught between the edge  135  and blade  140  during installation. 
     The cutting edge  136  is divided into sections that are relatively shorter than the blade  140 , such that each section must be individually installed. The cutting edge  136  and wear plate  138  are traditionally the same length (considering the aggregate length of the cutting edge sections), however, the wear plate  138  is traditionally not sectioned but rather comprises a single piece extending the entire length of the plow  140 . Nonetheless, the wear plate  138  is installed in generally the same manner as the cutting edge  136 . Thus, it shall be sufficient to explain that the wear plate  138  is positioned on the support  16  so that the center of gravity of the plate  138  is disposed over the wall  128 . The height of the holder  16  is adjusted and the cart  10  is moved as necessary to align the attachment holes in the wear plate  138  with the corresponding attachment holes  146  defined in the blade  140 . It will be appreciated that the bolts  148  projecting forwardly from the cutting edge  136  will facilitate such alignment. As shown in FIG. 3, the upright wall  126  will be disposed between the cutting edge  136  and wear plate  138  once the attachment holes are aligned. This will consequently require the holder  16  to be lowered or the cart  10  to be moved laterally beyond one of the ends of the blade  140  so as to remove the wall  126  from the space between the plates  136  and  138  and thereby permit the wear plate  138  to be placed against the cutting edge  136 . If the cart  10  is to be moved laterally, the tongue  14  may be installed on the side attachment bracket  58  to facilitate such movement. 
     The plate holder  18  operates in generally the same manner as the plate holder  16 . However, the plate holder  18  is designed to support the cutting edge  136 . and wear plate  138  at a slightly smaller angle relative to horizontal, as perhaps best shown in FIG.  4 . In particular, the cutting edge  136  is supported by the holder  18  at an angle that more closely corresponds to the angle of the underbody blade  142 . Those ordinarily skilled in the art will appreciate that there is traditionally little clearance (e.g., five to seven inches) below the underbody blade  142 . The plate holder  18  is particularly effective during replacement of plates on the underbody blade  142  because of its relatively lower location on the cart  10 . It will also be appreciated that plate holder  18  is typically disposed at or near its lowermost position during installation of the plates on the underbody blade  142 , and consequently, there will be little, if any, adjustment of the height of the plate holder  18  as the attachment holes are aligned. As shown in FIG. 4, the upright wall  132  of the plate holder  18  is disposed behind the cutting edge  136 . Because the plate holder  18  is at or near its lowermost position, the cart  10  will need to be moved laterally beyond one of the ends of the blade  142 . 
     An alternative embodiment of the present invention is shown in FIGS. 5 and 6, wherein an extension boom  200  is provided on the cart  201 . The extension boom  200  is designed to hold both the cutting edge  136  and the wear plate  138 . Moreover, as perhaps best shown in FIG. 5, the extension boom  200  is of sufficient length to simultaneously support all of the cutting edge sections. In this respect, installation of the entire cutting edge  136  and the wear plate  138  may be accomplished at one time. 
     The extension boom  200  preferably comprises a U-shaped channel presenting a bottom support wall  202  and a pair of spaced apart upright walls  204  and  206 . The cart  201  is generally similar to that shown in FIGS. 1-4, with the extension boom  200  preferably being attached to the plate holder  208  so as to be carried on the cart frame (not shown) by the parallelogram linkage  210 . It is particularly noted that such attachment is accomplished by a plurality of nut and bolt assemblies  212  that cooperatively present a projection on the support wall  202  spaced from the upright wall  206 . A pair of clamping mechanisms  214  (only one of the clamping mechanisms being shown in the drawing figures) are attached to the upright wall  204 . As shown in FIG. 5, each of the mechanisms includes a shiftable clamping element  216  projecting through an open slot  218  defined in the wall  204 , for purposes which will subsequently be described. One suitable clamping mechanism is available as Part No. 210 from Dover Resources Co. of Troy, Mich. However, it is entirely within the ambit of the present invention to utilize various other clamping mechanisms (e.g., a traditional C-clamp would suffice). 
     The extension boom  200  is used in virtually the same manner as the plate holders  16  and  18 , although the boom  200  does have a few beneficial exceptions. The sections of the cutting edge  136  are preferably first placed end-to-end on the support wall  202 , with the nut and bolt assemblies  212  serving to maintain the edge  136  in an upright orientation against the wall  206 . It is noted that the illustrated boom  200  is not quite as long as the edge  136 , however, the boom  200  is of sufficient length to ensure that the center of gravity for each of the outermost sections may be securely disposed over the support wall  202 . The unitary wear plate  138  is then placed on the support wall  202  between the cutting edge  136  and the nut and bolt assemblies  212 . The attachment holes defined in the plates  136  and  138  are subsequently aligned, which should occur naturally when the plates are superimposed. If desired, pins  220  may be inserted into the aligned attachment holes, with at least one pin preferably being associated with each section of the cutting edge  136 . The clamping mechanisms  214  are then operated to clamp the plates  136  and  138  to one another and against the upright wall  206 . The alignment pins  220  may be removed at this time, although they are preferably left in the attachment holes to facilitate attachment to the blade  140 . The height of the boom  200  may then be adjusted and the cart  201  may be moved until the pins  220  are received in the corresponding attachment holes defined in the blade  140 . Bolts (not shown) can subsequently be inserted into the open attachment holes (the holes not having a pin received therein), and the pins  220  may then be removed so that the remaining bolts can be installed. Thereafter, the plates  136  and  138  are unclamped and the cart  201  can be moved away from the blade  140 . 
     The preferred forms of the invention described above are to be used as illustrations only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention. 
     The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.