Patent Publication Number: US-2022228821-A1

Title: Method of using a lance cleaning system with movable support

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Divisional of U.S. patent application Ser. No. 16/737,150, filed Jan. 8, 2020, the entire disclosure of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to water jet equipment. More particularly, the present disclosure is directed to water jet equipment that is used for cleaning objects. Specifically, the present disclosure is water jet equipment that includes a support frame comprised of a plurality of stackable trollies that support a plurality of lances as those lances are inserted into and withdrawn from heat exchanger tubes during a cleaning operation of the same. 
     BACKGROUND 
     Background Information 
     Heat exchangers are used for the transfer of heat from a solid object to a fluid or from one fluid to another fluid. A heat exchanger will generally include a plurality of elongate conduits or tubes that carry steam or water in the bores thereof. If two fluids are involved, one of the fluids passes through the bores of the conduits or tubes and the other of the fluids passes around an outside of the tubes. The tubes terminate in an end plate which defines a plurality of openings therein. Each opening aligns with a bore of one of the tubes in the heat exchanger. Over time, deposits from the fluid traveling through the tube bores tends to accumulate on the interior surface of the tubes and affect the efficiency of the heat exchange process. The deposits may accumulate to the point that one or more tubes in the heat exchanger become blocked. 
     It is therefore customary to scour the deposits from the interior surfaces of the tubes from time to time. This cleaning is typically accomplished using a high pressure water jet to blast away the deposited solid materials. In particular, a lance or washer arm is connected to a high pressure water supply and a nozzle at the free end of the lance is systematically introduced into the bore of each tube through an associated opening in the heat exchanger&#39;s end plate. The high pressure water jet is sprayed out of the nozzle and into the bore to blast away the deposits. The water pressure in a lance may easily exceed 10,000 psi with flow rates in excess of 100 gallons per minute. 
     There are a number of problems inherent in using this type of water jet equipment to clean heat exchanger tubes. For example, it is very difficult to keep the lance from buckling and bending while it is being guided into and out of the tube bores. A more serious problem, however, is jet reaction from the high pressure stream. Since the fluid is forced through the lance at extremely high pressures (in excess of 10,000 psi) the fluid discharge from the lance tip can blow backward when it strikes a blockage in a tube bore or if the operator accidentally directs the fluid toward a solid region of the end plate instead of into a bore of a tube. The blowback can strike the operator guiding the lance and can injure him or her. 
     In order to reduce the possibility of the lance buckling as it is introduced into or removed from a tube bore, the PRIOR ART has proposed an apparatus for supporting a rear portion of the lance in an elongated channel member which has an open top. In other words, the PRIOR ART has proposed supporting the rear portion of the lance in a U-shaped channel support. The nozzle end (i.e., operating end) of the lance is fed from the U-shaped channel member and into the tube bore through a vertically-oriented separator plate positioned at the front end of the channel member. A drive mechanism, comprising a set of motor-driven friction rollers, engages the lance immediately rearward of the separator plate, i.e., in a position rearward of the separate plate relative to the nozzle. The drive mechanism moves the lance forwardly toward the tube bore and along the U-shaped channel member. A major portion of the lance is supported in the open channel member behind the drive rollers and the motor. One of the major issues with this PRIOR ART apparatus is that, in many instances, the lance that is being used is quite long and even though the rear portion of the lance is supported, the lance tends to flex and buckle and is generally difficult to accurately position into the tube bore. This may put the operator at risk if the high pressure water jet contacts the end plate and deflects backward toward the operator of the water jet equipment. 
     SUMMARY 
     There is therefore a need in the art for improved heat exchanger cleaning technology. The apparatus and method discussed herein addresses the shortcomings of the prior art. 
     In one aspect, the present disclosure may provide an assembly for cleaning elongated tubes comprising: a rail, a rotation mechanism operatively engaged with the rail, at least one lance extending outwardly from the rotation mechanism and over the rail, a translation mechanism coupled with the rotation mechanism and being operable to move the rotation mechanism and the at least one lance in unison in one of a first direction and a second direction relative to the rail, and at least one trolley operatively engaged with the rail and supporting a portion of the at least one lance; said at least one trolley being movable along the rail in the one of the first direction and the second direction in response to operation of the translation mechanism. This exemplary embodiment or another may provide the at least one trolley defines at least one opening therein and the at least one lance extends through the at least one opening. This exemplary embodiment or another may provide the at least one trolley includes one or more wheels that engage the rail. This exemplary embodiment or another may provide at least one rail stop fixedly engaged on the rail; wherein the at least one rail stop arrests movement of the at least one trolley in the second direction. This exemplary embodiment or another may provide at least one locking mechanism that selectively secures the at least one trolley to the at least one rail stop. This exemplary embodiment or another may provide the locking mechanism comprises a first magnetic component provided on the at least one trolley and a second magnet component provided on the at least one rail stop, and wherein the first and second magnetic component are selectively magnetically attracted to each other. This exemplary embodiment or another may provide the at least one trolley comprises a plurality of trollies and the at least one rail stop comprises a plurality of rail stops, wherein each rail stop is dedicated to arrest the movement of on one of the plurality of trollies. This exemplary embodiment or another may provide a pusher operatively engaged with the translation mechanism, said pusher engaging the at least one trolley to impart motion in the first direction thereto. This exemplary embodiment or another may provide the at least one trolley comprises a plurality of trollies and the assembly further comprises: a stacker operatively engaged with one of the translation mechanism and the rotation mechanism, and a channel defined in each of the plurality of trollies, wherein the stacker is selectively receivable through the channel of one or more of the plurality of trollies when the translation mechanism moves the rotation mechanism in the first direction. This exemplary embodiment or another may provide a puck provided on the stacker, said puck being selectively movable from an un-deformed state to a deformed state to move through the channel of the one or more of the plurality of trollies. This exemplary embodiment or another may provide a pusher operatively engaged with the translation mechanism, said pusher engaging the at least one trolley to impart motion in the first direction thereto. This exemplary embodiment or another may provide at least one lance comprises a plurality of lances, and wherein the rotation mechanism is configured to rotate each of the plurality of lances an axis extending along a length of the respective lance. 
     In another aspect, the present disclosure may provide a method of cleaning elongated tubes comprising: positioning a terminal end of at least one lance adjacent an opening to an elongated tube bore, rotating the at least one lance about an axis utilizing a rotation mechanism movably mounted on a support rail, supporting the at least one lance with one or more trolleys engaged on the support rail forwardly of the rotation mechanism, activating a translation mechanism, moving linearly, with the translation mechanism, the rotation mechanism and the at least one lance in a first direction along the support rail, advancing the at least one lance in the first direction toward the opening and into the tube bore, moving the one or more trolleys along the rail as the translation mechanism moves the least one lance and the rotation mechanism in the first direction. This exemplary embodiment or another may provide connecting the at least one lance to a source of high pressure fluid, and spraying a volume of high pressure fluid out of the terminal end of the at least one lance and into the tube bore. This exemplary embodiment or another may provide the moving of the one or more trolleys along the support rail in the first direction is preceded by: disengaging a locking mechanism that secures at least one of the one or more trolleys to a rail stop engaged on the support rail. This exemplary embodiment or another may provide the moving of the one or more trolleys in the first direction includes: contacting at least one of the one or more trolleys with a pusher extending forwardly from the translation mechanism, and imparting motion to the at least one of the one or more trolleys with the pusher. This exemplary embodiment or another may provide stacking the one or more trolleys on a stacker when the one or more trolleys are moved in the first direction. This exemplary embodiment or another may provide moving the translation mechanism in a second direction along the support rail, and moving the rotation mechanism and the at least one lance in the second direction with the translation mechanism. This exemplary embodiment or another may provide withdrawing, progressively, the stacker from the one or more trolleys, contacting, with a puck provided on the stacker, a front surface of a forwardmost one of the one or more trolleys, and imparting motion in the second direction to the one more trolleys with the puck. This exemplary embodiment or another may provide engaging, progressively, each of the one or more the trolleys with an associated one of a plurality of dedicated rail stops provided on the rail, and arresting, progressively, motion of the one of the one or more trolleys in the second direction. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       A sample embodiment of the disclosure is set forth in the following description, is shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims. The accompanying drawings, which are fully incorporated herein and constitute a part of the specification, illustrate various examples, methods, and other example embodiments of various aspects of the disclosure. It will be appreciated that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of another element may be implemented as an external component and vice versa. Furthermore, elements may not be drawn to scale. 
         FIG. 1  is a left side elevation view of an exemplary lance cleaning system with movable support in accordance with the present disclosure. 
         FIG. 2  is a right side elevation view of the exemplary lance cleaning system of  FIG. 1 . 
         FIG. 3  is a front left side perspective view of an end guide of the lance cleaning system shown engaged with the rail, and showing a plurality of lances (in phantom) extending outwardly from the tubes of the end guide. 
         FIG. 4  is a front left side perspective view of a transition guide of the lance cleaning system shown engaged with a section of the rail. 
         FIG. 5  is a front left side perspective view of a stationary lance guide of the lance cleaning system shown engaged with a section of a rail of the lance cleaning system. 
         FIG. 6  is a front, left side perspective view of an exemplary trolley assembly of the lance cleaning system, in particular the second trolley assembly, shown engaged with an exemplary rail stop of the lance cleaning system, in particular the second rail stop thereof. 
         FIG. 7  is an exploded front, left side perspective view of the exemplary trolley assembly and rail stop of  FIG. 6 . 
         FIG. 8A  is a front elevation view of the tenth rail stop and the leg from the tenth trolley. 
         FIG. 8B  is a front elevation view of the eighth rail stop and the leg from the eighth trolley. 
         FIG. 8C  is a front elevation view of the sixth rail stop and the leg from the sixth trolley. 
         FIG. 8D  is a front elevation view of the fourth rail stop and the leg from the fourth trolley. 
         FIG. 8E  is a front elevation view of the second rail stop and the leg from the second trolley. 
         FIG. 8F  is a front elevation view of the first rail stop. 
         FIG. 9  is a block diagram showing the relationship of  FIG. 9A  and  FIG. 9B , which together are an enlargement of the highlighted region of  FIG. 1 . 
         FIG. 9A  is an enlargement of a first portion of the highlighted region of  FIG. 1  showing exemplary trolley assemblies of the lance cleaning system. 
         FIG. 9B  is an enlargement of a second portion of the highlighted region of  FIG. 1  showing a rotation mechanism and a translation mechanism of the lance cleaning system. 
         FIG. 10  is a top plan view of the exemplary trolley assemblies taken along line  10 - 10  of  FIG. 9A . 
         FIG. 11  is a top plan view of the rotation mechanism and translation mechanism taken along line  11 - 11  of  FIG. 9B . 
         FIG. 12  is a partial cross-section of the rotation mechanism taken along line  12 - 12  of  FIG. 9B . 
         FIG. 13  is a partial cross-section of the rotation mechanism taken along line  13 - 13  of  FIG. 9B . 
         FIG. 14  is a partial cross-section of the translation mechanism taken along line  14 - 14  of  FIG. 9B . 
         FIG. 15  is a partial cross-section of the translation mechanism taken along line  15 - 15  of  FIG. 14 . 
         FIG. 16  is a left side elevation view of the exemplary lance cleaning system positioned to clean a tube bundle of an exemplary heat exchanger. 
         FIG. 16A  is a rear end elevation view of an end plate of the exemplary heat exchanger taken along line  16 A- 16 A of  FIG. 16 . 
         FIG. 17A  is a partial cross-section of the ninth trolley taken along line  17 A- 17 A of  FIG. 16  showing a deformable puck on the stacker adjacent the back of the ninth trolley and poised to enter the channel defined in the ninth trolley. 
         FIG. 17B  is a partial cross-section of the ninth trolley similar to  FIG. 17A  but showing the puck being deformed as it moves through the channel defined in the ninth trolley. 
         FIG. 17C  is a partial cross-section of the ninth trolley similar to  FIGS. 17A and 17B  showing the puck returned to its non-deformed state. 
         FIG. 18A  is a left side elevation view of the exemplary lance cleaning system shown in operation and with the translation mechanism moved to a first position and the lances moved inwardly into the bores of tubes in the heat exchanger tube bundle. 
         FIG. 18B  is a left side elevation view of the exemplary lance cleaning system shown in operation and with the translation mechanism moved to a second position and advancing the lances further inwardly into the bores of tubes in the heat exchanger tube bundle. 
         FIG. 18C  is a left side elevation view of the exemplary lance cleaning system shown in operation and with the translation mechanism moved to a third position and advancing the lances still further inwardly into the tube bores. 
         FIG. 18D  is a left side elevation view of the exemplary lance cleaning system shown in operation and with the translation mechanism moved to a fourth position and advancing the lances still further inwardly into the tube bores. 
         FIG. 18E  is a left side elevation view of the exemplary lance cleaning system shown in operation and with the translation mechanism moved to a fifth position and advancing the lances further inwardly into the tube bores. 
         FIG. 18F  is a left side elevation view of the exemplary lance cleaning system shown in operation and with the translation mechanism moved to a sixth position where the lances have been fully advanced into the heat exchanger and the trolley assemblies are all stacked onto a stacker of the lance cleaning system. 
         FIG. 19A  is a partial cross-section of a tenth trolley of the lance cleaning system shown engaged with the rail and taken along line  19 A- 19 A of  FIG. 18A . 
         FIG. 19B  is a partial cross-section of an eighth trolley of the lance cleaning system shown engaged with the rail and taken along line  19 B- 19 B in  FIG. 18B . 
         FIG. 19C  is a partial cross-section of a sixth trolley of the lance cleaning system shown engaged with the rail and taken along line  19 C- 19 C in  FIG. 18C . 
         FIG. 19D  is a partial cross-section of a fourth trolley of the lance cleaning system shown engaged with the rail and taken along line  19 D- 19 D in  FIG. 18D . 
         FIG. 19E  is a partial cross-section of a second trolley of the lance cleaning system shown engaged with the rail and taken along line  19 E- 19 E in  FIG. 18E   
         FIG. 20  is a top plan view of the stacked trolleys of the lance cleaning system taken along line  20 - 20  of  FIG. 18F . 
         FIG. 21  is a top plan view of the stacked trollies of the lance cleaning system beginning to be move backwards by the stacker and in a direction away from the heat exchanger, and showing only part of the lances for clarity of illustration. 
         FIG. 22A  is a partial cross-section of the stacked trollies taken along line  22 A- 22 A of  FIG. 21  showing a puck that is engaged with the stacker engaged with the first trolley and causing the stacked trollies to move backwards as the stacker is retracted. 
         FIG. 22B  is a partial cross-section of the stacked trollies similar to  FIG. 22A  but showing the puck being deformed as the puck moves through a channel opening defined in the first trolley. 
         FIG. 22C  is a partial cross-section of the stacked trollies similar to  FIGS. 22A and 22B  showing the first trolley disengaged from the trolley stack and the puck on the stacker engaging the second trolley in the trolley stack. 
         FIG. 23  is a left side elevation view of the lance cleaning system as illustrated in  FIG. 22C  and showing the first trolley disengaged from the trolley stack and the puck engaging the second trolley of the trolley stack while the stacker is being retracted. 
     
    
    
     Similar numbers refer to similar parts throughout the drawings. 
     DETAILED DESCRIPTION 
     A new lance cleaning system  10  and method of operation thereof is depicted in  FIGS. 1-23  and discussed in the present disclosure. System  10  is a new and improved apparatus for performing cleaning operations, as will be discussed hereafter, but system  10  may also be used in other applications. 
     Referring now to  FIG. 1  and  FIG. 2 , an exemplary lance cleaning system  10  that includes movable supports is shown ready for operation and in an expanded position. Lance cleaning system  10  may interchangeably be referred to herein by the terms “lance cleaning system  10 ” and “system”  10 . System  10  has a front end  10 A and a rear end  10 B transversely opposed to the front end  10 A. A longitudinal axis “Y” ( FIG. 10 ) of system  10  extends between front end  10 A and rear end  10 B. 
     System  10  includes a support rail  12  that has a first end and a second end. Support rail  12  extends longitudinally from proximate front end  10 A of system  10  to proximate rear end  10 B of system  10 .  FIGS. 1, 2 and 4  show that rail  12  comprises an elongate body having a top side  12 A, a bottom side  12 B, a left side  12 C, and a right side  12 D. Rounded upper edges  12 E project outwardly from the corners where top side  12 A intersects left side  12 C and right side  12 D, respectively. Rounded lower edges  12 F project outwardly from the corners where bottom side  12 B intersects left side  12 C and right side  12 D, respectively. Edges  12 E,  12 F extend for substantially the entire length of rail  12  from proximate first end to proximate second end thereof. Rail  12  is hollow and defines a bore  12 G ( FIG. 4 ) therethrough that extends from proximate first end to proximate second end. The provision of bore  12 G helps to reduce the overall weight of rail  12 . 
     As best seen in  FIG. 10 , rail  12  also includes a track  12 H that extends for at least a portion of top side  12 A from proximate the second end of rail  12  (i.e., proximate rear end  10 B) and towards the first end of rail  12  (i.e., towards front end  10 A). Track  12 H, as illustrated herein, comprises a plurality of spaced apart apertures  12 H′ that are in fluid communication with bore  12 G. The purpose of track  12 H will be discussed later herein. It should be understood that not all figures provided herewith shows track  12 H for clarity of illustration. Track  12 H does, however, extend along substantially the entire length of rail  12 . 
     Rail  12  is supported a distance vertically above the ground “G” by a support frame  11  and an indexer  14 . As illustrated in  FIGS. 1 and 2 , indexer  14  extends upwardly from a base  14 A. A plurality of wheels or casters  14 B extend downwardly from base  14 A and contact ground “B”. Casters  14 B may be utilized to move indexer  14  and thereby system  10  across the ground “B”. One or more locking mechanisms  14 C are engaged with base  14 A and are selectively extendable to contact ground “G” to secure system  10  in a particular position. Indexer  14  may further include various operating components  14 D for controlling indexer  14 . Support frame  11  may include a base  11 A and a plurality of frame members  11 B that extend upwardly from the base  11 A and which may meet at an apex  11 C. Base  11 A and/or frame members  11 B contact ground “G”. A suspension rod  11 D is shown in  FIGS. 1 and 2  as extending downwardly from apex  11 C and attaching to the second end of rail  12 . As indicated earlier herein, support frame  11  and indexer  14  together hold system  10  a distance “D” above the ground “G”. The distance “D” may be varied as needed for the operation of system  10 . It will be understood that any suitable support frame  11  and indexer  14  may be used in conjunction with system  10 . 
     System  10 , shown in  FIGS. 1 and 2  includes a plurality of components that are supported by or carried on rail  12 . These components include an end guide  16  ( FIG. 3 ), a transition guide  18  ( FIG. 4 ), a lance guide  20  ( FIG. 5 ), a first trolley  22  ( FIG. 1 ), a first rail stop  24  ( FIG. 2 ), a second trolley  26 , a second rail stop  28  ( FIG. 1 ), a third trolley  30 , a third rail stop  32  ( FIG. 2 ), a fourth trolley  34 , a fourth rail stop  36  ( FIG. 1 ), a fifth trolley  38 , a fifth rail stop  40  ( FIG. 2 ), a sixth trolley  42 , a sixth rail stop  44  ( FIG. 1 ), a seventh trolley  46 , a seventh rail stop  48  ( FIG. 2 ), an eighth trolley  50 , an eighth rail stop  52  ( FIG. 1 ), a ninth trolley  54 , a ninth rail stop  56  ( FIG. 2 ), a tenth trolley  58 , and a tenth rail stop  60  ( FIG. 1 ). All of the trolleys  22 ,  26 ,  30 ,  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and  58  are substantially identical to each other in structure and function. An exemplary trolley, the second trolley  26 , is shown in detail in  FIGS. 6 and 7 . Each trolley is selectively engaged by way of a differently configured rail stop  24 ,  28 ,  32 ,  36 ,  40 ,  44 ,  48 ,  52 ,  56 , and  60 . In particular, the differently configured rail stops  24 ,  28 ,  32 ,  36 ,  40 ,  44 ,  48 ,  52 ,  56 , and  60  are engaged with alternating sides of the associated trolleys as will be described later herein with reference to  FIGS. 8A-8F . This alternating arrangement helps the trolleys move smoothly along rail  12 . It will be understood that fewer than ten trolleys and rail stops may be supported by rail  12 . Alternatively, more than ten trolleys and rail stops may be supported by rail  12 . 
     The end guide  16 , transition guide  18 , lance guide  20 , and the various trolleys  22 ,  26 ,  30 ,  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and  58 , together support a plurality of lances  62  ( FIGS. 9A, 9B and 10 ) that are connected to a report high pressure source of fluid. In one embodiment, the high pressure fluid is water but it will be understood that air or other gases and liquids may be piped through lances  62 . Additionally, the fluid (liquid or gas) may have solid particulate matter entrained therein. 
     The attached figures illustrate five lances  62  used in system  10 . It will be understood that fewer than five lances  62  may be provided in system  10 . In other instances, more than five lances  62  may be utilized. Rail  12  may further support a stacker  64  ( FIGS. 9A, 9B and 10 ), a rotation mechanism  66  ( FIGS. 3B, and 5-7 ), and a translation mechanism  68  ( FIGS. 9B, 11, 14, and 15 ). 
     The various components of system  10  will now be described in greater detail. Referring to  FIG. 3 , the end guide  16  is illustrated. End guide  16  includes a housing that is generally U-shaped when viewed from above and includes a front panel  16 A, a left side panel  16 B, and a right side panel  16 C. The housing is fixedly engaged with a front end of rail  12 . In particular, front panel  16 A abuts the front end of rail  12  and left and right side panels  16 B,  16 C of housing  16 A abut and are secured to the left and right sides  12 C,  12 D of rail  12  by one or more fasteners  17 . The fasteners  17  are passed through aligned openings defined in left and right side panels  16 B,  16 C and in rail  12 . A plurality of tubes  16 D extend outwardly from a front surface of front panel  16 A. Tubes  16 D pass through apertures  16 E defined in front panel. The apertures  16 E are horizontally aligned with each other and are located so as to be positioned a distance vertically above top  12 A of rail  12 . Each tube  16 D terminates in a nosepiece  16 F. Each tube  16 D defines a bore  16 G therethrough that runs the length of tube  16 D. Each bore  16 G is configured to be able to receive one of the lances  62  therethrough. 
     As will be understood, if fewer than five lances  62  are utilized in system  10 , then a complementary number of apertures  16 E,  16 D, and nosepieces  16 F may be utilized in end guide  16 . As will be further understood, if more than five lances  62  are utilized in system  10 , then a complementary number of apertures  16 E,  16 D, and nosepieces  16 F may be utilized in end guide  16 . It should further be understood that even though five apertures  16 E,  16 D, and nosepieces  16 F are provided in end guide  16 , fewer than five lances  62  may be utilized in system  10  and then the lances  62  will simply be inserted through an appropriate number of apertures  16 E,  16 D, and nosepieces  16 F. 
       FIG. 4  shows the transition guide  18  that is positioned a distance longitudinally rearwardly of end guide  16 . Transition guide  18  includes a transition guide body  13 , a pair of mounting blocks  15  and a plurality of fasteners  17 A,  17 B. Transition guide body  13  is generally rectangular in shape and includes a top  13 A, a bottom  13 B, a front  13 C, a back  13 D, a left side  13 E, and a right side  13 F. Transition guide body  13  defines a plurality of apertures  13 G therethrough. Each aperture  13 G extends from front  13 C through to back  13 D. Transition guide body  13  is illustrated as defining five apertures  13 G therein; each of the apertures  13 G being shaped and sized to receive one of the five lances  62  therethrough. Apertures  13 G are aligned in a horizontal row that is substantially identical to the configuration shown in end guide  16 . As will be understood, if fewer than five lances  62  are utilized in system  10 , then a complementary number of apertures  13 G may be defined in transition guide body  13 . As will be further understood, if more than five lances  62  are utilized in system  10 , then a complementary number of apertures  13 G may be defined in transition guide body  13 . It should further be understood that even though five apertures  13 G are defined in transition guide body  13 , fewer than five lances  62  may be utilized in system  10  and then the lances  62  will simply be inserted through an appropriate number of apertures  13 G. 
     A channel  13 H is defined in transition guide body  13 . Channel  13 H extends between front  13 C and back  13 D of transition guide body  13  and extends downwardly to an opening defined in bottom  13 B. Channel  13 H is illustrated as being an inverted U-shape but it will be understood that in other embodiments, channel  13 H may be differently shaped. Channel  13 H is positioned, shaped, and sized to selectively receive stacker  64  therethrough during operation of system  10 . 
     Transition guide body  13  also defines a generally square or rectangular notch  13 J in each lower corner of the body, i.e., where bottom  13 B intersects the front, back, left side and right side  13 C- 13 F. These notches  13 J may be omitted. 
     Mounting blocks  15  are generally L-shaped when viewed from the front and are configured to engage the transition guide body  13  and rail  12 . A first mounting block  15  is engaged with a left side region of transition guide body  13  and a left side region of rail  12 . A second mounting block  15  is engaged with a right side region of transition guide body  13  and a right side region of rail  12 . The mounting blocks are mirror images of each other. Each mounting block  15  has a top  15 A, a bottom  15 B, a front  15 C, a back  15 D, an inside surface  15 E, and an outside surface  15 F. The inside surface  15 E defines a vertically-oriented recess  15 G that is shaped to receive one of the end regions (proximate left side  13 E or right side  13 F. The bottom  13 B of transition guide body  13  is positioned above a horizontal surface  15 H of each of the mounting blocks  15 . 
     Each of the inside surfaces  15 E of mounting blocks  15  also defines a horizontally-oriented slot  15 J that is located a distance vertically downward from horizontal surface  15 H and is positioned, shaped and sized to receive a portion of the curved edge  12 E of rail  12  therein. 
     Mounting blocks  15  also define a plurality off first holes (not shown) that extend between exterior surface  15 F and a region of interior surface  15 E which is located in the recess  15 G. A plurality of first fasteners  17 A pass through these first holes and into aligned holes defined in the associated one of the left side  13 E or right side  13 F of transition guide body  13 . First fasteners  17 A secure transition guide body  13  between mounting blocks  15 . A second hole ( 15 K) is defined in each mounting block  15  a distance vertically below the plurality of first holes. The second holes  15 K in the two mounting blocks  15  are aligned with each other and a fastener  17 B is passed therethrough. Second fastener  17 B secures mounting blocks  15  to each other and clampingly engage transition guide body between mounting blocks  15 . Second fastener  17 B is tightened to the point that transition guide  18  is retained in a fixed location along the length of rail  12 . If it is desired to reposition transition guide  18  for any reason, then second fastener  17 B is loosened, guide  18  is moved along the edges  12 E of rail  12  to a desired position, and then second fastener  17 B is tightened up once again. 
     Referring to  FIG. 5 , the lance guide  20  is shown. Lance guide  20  is substantially similar to transition guide in that it comprises a lance guide body  19  that is engaged with two opposed mounting blocks  21  by a plurality of fasteners  23 . Lance guide body  19  is substantially identical in structure and function to transition guide body  13  except for the arrangement of the openings therethrough which receive the lances  62 , as will be later described herein. Lance guide body  19  is generally rectangular in shape and includes a top  19 A, a bottom  19 B, a front  19 C, a back  19 D, a left side  19 E, and a right side  19 F. Transition guide body  19  defines a plurality of apertures  19 G therethrough. Each aperture  19 G extends from front  19 C through to back  19 D. Transition guide body  19  is illustrated as defining five apertures  19 G therein; each of the apertures  19 G being shaped and sized to receive one of the five lances  62  therethrough. Apertures  19 G are arranged in a pattern. In particular, apertures  19 G are arranged in two horizontally-oriented rows that are spaced a vertical distance apart from each other. The rows comprise an uppermost row (proximate top  19 A) and a lowermost row (proximate bottom  19 B).  FIG. 5  shows three apertures  19 G in the uppermost row and two apertures  19 G in the lowermost row. In the pattern, the apertures  19 G are also transversely staggered relative to each other. For example, each aperture  19 G in the lowermost row is located between two apertures of the uppermost row. It will be understood that the particular pattern of the apertures  19 G and therefore of the lances  62  may be varied by configuring the pattern of the apertures  19 G differently. As will be understood, if fewer than five lances  62  are utilized in system  10 , then a complementary number of apertures  19 G may be defined in lance guide body  19 . As will be further understood, if more than five lances  62  are utilized in system  10 , then a complementary number of apertures  19 G may be defined in lance guide body  19 . It should further be understood that even though five apertures  19 G are defined in lance guide body  19 , fewer than five lances  62  may be utilized in system  10  and then the lances  62  will simply be inserted through an appropriate number of apertures  19 G. 
     A channel  19 H is defined in lance guide body  19 . Channel  19 H extends between front  19 C and back  19 D of lance guide body  19  and extends downwardly to an opening defined in bottom  19 B. Channel  19 H is illustrated as being an inverted U-shape but it will be understood that in other embodiments, channel  19 H may be differently shaped. Channel  19 H is positioned, shaped, and sized to selectively receive stacker  64  therethrough during operation of system  10 . Lance guide body  19  also defines a generally square or rectangular notch  19 J in each lower corner of the body, i.e., where bottom  19 B intersects the front, back, left side and right side  19 C- 19 F. These notches  19 J may be omitted. 
     Mounting blocks  21  are substantially identical to mounting blocks  15  in function and are of the same general shape and structure as mounting blocks  15 . Because of the similarity between mounting blocks  15  and  21 , the various component parts of mounting blocks  21  have not been discussed herein or labeled in the drawings. One difference between mounting blocks  21  and mounting blocks  15  is that mounting blocks  21  are longer and extend downwardly for a distance beyond the bottom  12 B of rail  12 . Mounting blocks  15 , on the other hand, have a bottom  15 B that terminates at a location between upper edge  12 E and lower edge  12 F of rail  12 . Mounting blocks  21  define an upper slot  21 J, similar to slot  15 J, and configured to receive the upper edge  12 E of rail therein. Mounting blocks  21  differ from mounting blocks  15  in that the blocks  21  further define a lower slot  21 K that is positioned, shaped, and sized to receive lower edge  12 F of rail  12  therein. A plurality of first fasteners  23 A secure mounting blocks  21  to lance guide body  19 . A second fasteners  23 B and a third fastener  23 C secure the first mounting block  21  and second mounting block  21  to each other. 
     Second and third fasteners  23 B,  23 C secure mounting blocks  21  to each other and clampingly engage lance guide body  19  between them. Fasteners  23 B,  23 C are tightened to the point that lance guide  20  is retained in a fixed location along the length of rail  12 . If it is desired to reposition lance guide  20  for any reason, then fasteners  23 B,  23 C are loosened, guide  20  is moved along the edges  12 E,  12 F of rail  12  to a desired position, and then fasteners  23 B,  23 C are tightened up once again. 
     Referring particularly to  FIGS. 6 and 7 , an exemplary trolley and exemplary rail stop are shown. The exemplary trolley shown in these figures is the second trolley  26  but it should be understood that all of the trolleys  22 ,  26 ,  30 ,  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and  58  provided in system  10  are substantially identical in structure and function. The rail stop shown in  FIGS. 6 and 7  is the second rail stop  28 . Certain features of this second rail stop  28  are found in all of the rail stops  24 ,  28 ,  32 ,  36 ,  40 ,  44 ,  48 ,  52 ,  56 , and  60  used in system  10 . There are differences from one rail stop to the next and these will be pointed out with respect to the discussion relating to  FIGS. 12A through 12F . 
     Still referring particularly to  FIGS. 6 and 7 , second trolley  26  comprises a trolley body  27 , a plate  29 , a plurality of wheels  31 , and an arm  33   
     Trolley body  27  is generally rectangular in shape and includes a top  27 A, a bottom  27 B, a front  27 C, a back  27 D, a left side  27 E, and a right side  27 F. Plate  29  is generally rectangular and includes a top  29 A, a bottom  29 B, a front  29 C, a back  29 D, a left side  29 E, and a right side  29 F. Bottom  27 B of trolley body  27  abuts top  29 A of plate  29  and a plurality of fasteners  35  are utilized to secure trolley body  27  to plate  29 . 
     Trolley body  27  defines a plurality of apertures  27 G therethrough. Each aperture  27 G extends from front  27 C through to back  27 D. Trolley body  27  is illustrated as defining five apertures  27 G therein; each of the apertures  27 G being shaped and sized to receive one of the five lances  62  therethrough. As will be understood, if fewer than five lances  62  are utilized in system  10 , then a complementary number of apertures  27 G may be defined in trolley body  27 . As will be further understood, if more than five lances  62  are utilized in system  10 , then a complementary number of apertures  27 G may be defined in trolley body  27 . It should further be understood that even though five apertures  27 G are defined in trolley body  27 , fewer than five lances  62  may be utilized in system  10  and then the lances  62  will simply be inserted through an appropriate number of apertures  27 G. 
       FIGS. 6 and 7  also illustrate that the apertures  27 G are arranged in a pattern. In particular, apertures  27 G are arranged in two horizontally-oriented rows that are spaced a vertical distance apart from each other. The rows comprise an uppermost row (proximate top  27 A) and a lowermost row (proximate bottom  27 B). The figures show three apertures  27 G in the uppermost row and two apertures  27 G in the lowermost row. In the pattern, the apertures  27 G are also transversely staggered relative to each other. For example, each aperture  27 G in the lowermost row is located between two apertures of the uppermost row. It will be understood that the particular pattern of the apertures  27 G and therefore of the lances  62  may be varied by configuring the pattern of the apertures  27 G differently. 
     A channel  27 H is defined in trolley body  27 . Channel  27 H extends between front  27 C and back  27 D of trolley body  27  and extends downwardly to an opening defined in bottom  27 B. If plate  29  was not engaged with trolley body  27 , channel  27 H would be accessible through the opening in bottom  27 B. Channel  27 H is illustrated as being an inverted U-shape but it will be understood that in other embodiments, channel  27 H may be differently shaped. Channel  27 H is positioned, shaped, and sized to selectively receive stacker  64  therethrough during operation of system  10 . 
     Trolley body  27  also defines a generally square or rectangular notch  27 J in each lower corner of the body, i.e., where bottom  27 B intersects the front, back, left side and right side  27 C- 27 F. Fasteners  37  are used to mount wheels  31  to body  27  and plate  29 . The heads of fasteners  37  (or nuts engaged with fasteners  37 ) are received in the notches  27 J. 
     Plate  29  defines a variety of different openings that extend between top  29 A and bottom  29 B. Some of these openings receive the fasteners  35 ,  37  therethrough but are not shown in  FIGS. 6 and 7 . Additionally, a pair of longitudinally-oriented and rectangularly-shaped slots  29 G are defined in opposed regions of plate  29 . In particular, the slots  29  are arranged on either side of trolley body  27 , particularly between sides  27 E and  29 E, and between sides  27 F and  29 F. A plurality of holes  29 H are defined in plate and proximate slots  29 G. As illustrated, two holes  29 H are located laterally on either side of each slot  29 G. As will be discussed later herein, one or the other of the groups of slots  29 G and associated holes  29 H is utilized to secure arm  33  to plate  29 . Because this is the second trolley  26 , the arm  33  is engaged in the slot  29 G located proximate left side  29 E of plate  29 . Arm  33  is engaged with plate  29  at this location because it is then in the correct position to selectively be engaged with second rail stop  28 , as will be described later herein. 
     Recesses  29 J are defined in each of the front corners of plate  29 , i.e., where front  29 C intersects left side  29 E and right side  29 F, respectively. The notches  29 J extend from top  29 A through to bottom  29 B. Resilient bumpers  39  are engaged with the plate  29  and each bumper  39  is seated within one of the recesses  29 J. Bumpers  39  are secured to plate  29  in any suitable manner. Bumpers  39  may be fabricated from a material such as rubber so that impacts to trolley body  27  as trolley body slides along rail  12  may be absorbed thereby. 
     Each wheel  31  that is engaged with plate  29  and trolley body  27  by fasteners  37  is configured to engage rail  12 . Each wheel  31  defines an annular C-shaped groove  31 A therein. Groove  31 A is complementary in curvature to the radius of curvature of the upper edges  12 E of rail  12 . The lateral spacing between the two wheels  31  proximate the left side  29 E of plate  29  and the two wheels  31  proximate the right side  29 F of plate  29  is complementary to the spacing between the upper edges  12 E of rail  12 . When second trolley  26  is engaged with rail  12 , the wheels  31  proximate left side  29 E of plate  29  receive the upper edge  12 E of rail  12 , where the upper edge  12 E is the one located at the intersection of top  12 A and left side  12 D. The wheels  31  proximate right side  29 F of plate  29  receive the upper edge  12 E located at the intersection of top  12 A and right side  12 C of rail  12 . The engagement between wheels  31  and rail  12  allows second trolley  12  to selectively move along rail  12  in one a first direction (toward front end  10 A) and a second direction (toward rear end  10 B). 
     As indicated earlier herein, second trolley  26  also includes an arm  33  that extends downwardly for a distance belong bottom  29 B of plate  29  ( FIG. 6 ). As illustrated, arm  33  is a generally T-shaped component when viewed from the front and includes a base  33 A and a leg  33 B. Base  33 A is horizontally-oriented and may be generally square in shape when viewed from above. Base  33 A includes an upper surface  33 C and a lower surface  33 D ( FIG. 7 ). Leg  33 B extends vertically downwardly from lower surface  33 D. A plurality of through-holes  33 E are defined in base  33 A and extend from upper surface  33 C through to lower surface  33 D. Holes  33 E are arranged in two laterally spaced-apart rows on either side of leg  33 B. The arrangement and spacing of holes  33 E is complementary to the arrangement and spacing of holes  29 H in plate  29 . Leg  33 B is located between the two laterally-spaced apart rows of holes  33 E and is shaped and sized to be received through slot  29 G defined in plate  29 . Leg  33 B is thereby generally rectangular in cross-sectional shape. Arm  33  is engaged with plate  29  by inserting leg  33 B through slot  29 G and then inserting fasteners  41  through the aligned holes  33 E,  29 H. Each fastener  41  may be a lock screw or something similar that does not require a nut to secure the fastener in place. 
     As best seen in  FIG. 7 , leg  33 B defines a plurality of apertures  33 F that extend between a left side surface and a right side surface of leg  33 B. Apertures  33 F are therefore oriented at right angles to the longitudinal axis “Y” of system  10  when trolley  26  is engaged with rail  12 . A locking member  43  is secured to leg  33 B. Locking member  43  comprises a generally L-shaped base when viewed from above. The base includes a first leg  43 A and a second leg  43 B that meet at right angles to each other. First leg  43 A defines a plurality of openings  43 C therein that extend between a left side surface and a right side surface of the first leg  43 A. The arrangement, shape, and size of openings  43 C is complementary to the arrangement, shape, and size of apertures  33 F in leg  33 B. After leg  33 B has been inserted through slot  29 G and fasteners  41  have secured base  33 A to plate  29 , locking member  43  is positioned in contact with the end of leg  33 B that defines apertures  33 F therein. In particular, leg  33 B is received in the right-angled corner defined between first leg  43 A and second leg  43 B of locking member  43  and so that the right side surface of leg  33 B abuts the left side surface of locking member  43 . Fasteners  45  are inserted through the aligned apertures  33 F and openings  43 C to secure locking member  43  to leg  33 B. 
       FIG. 7  shows that locking member  43  is provided with a boss  43 D that extends outwardly from second leg  43 C in a direction opposite to first leg  43 A. Consequently, when second trolley  26  is engaged on rail, boss  43 D will be generally aligned parallel to longitudinal axis “Y”. Boss  43 D is fabricated from a magnetic or ferromagnetic material. Boss  43 D is illustrated as being a truncated cone but any other suitable shape boss  43 D may be utilized. Locking member  43  is utilized to temporarily secure second trolley  26  to second rail stop  28 , as will be later described herein. It will be understood that other types of locking member may be utilized on second trolley  26  in the place of locking member  43 . 
     While only the second trolley  26  has been described in detail herein, it will be understood that all of the trolleys  22 - 58  are substantially identical except for the few differences pointed out herein. Because of the substantial similarity between the trolleys  22 - 58 , reference characters used in the description of trolley  26  will be utilized in this description to also identify features and components of any of the other trolleys under discussion in any particular part of this disclosure unless otherwise specified. 
       FIGS. 6, 7, and 8E  show second rail stop  28  in greater detail. Rail stop  28  comprises a block of material having a top  28 A, a bottom  28 B, a front  28 C, a back  28 D, a left side  28 E, and a right side  28 F. A first recess  28 G is defined in top  28 A and this recess  28 G extends downwardly toward bottom  28 B but terminates a distance away from bottom  28 B. Recess  28 G also extends from front  28 C through to back  28 D. Two grooves  28 H,  28 J are defined in the block of material extending from front  28 C through to back  28 D. Each of the grooves  28 H,  28 J is generally square in cross-sectional shape and is cut deeper than recess  28 G. Groove  28 H is spaced laterally from groove  28 J. A raised region  28 K extends upwardly beyond grooves  28 H,  28 J and into recess  28 G. Raised region  28 K is located a distance vertically lower than top  28 A. The shape of raised region  28 K and of the two grooves  28 H,  28 J is complementary to the shape of the lower portion of rail  12 . In particular, grooves  28 H,  28 J are configured to each receive one of the curved regions  12 F of rail  12  therein. When the curved regions  12 F are received in grooves  28 H,  28 J, the bottom  12 B of rail stop  28  rests on raised region  28   k  and second rail stop  26  is latched to rail  12 . 
     Rail stop  28  further defines a pair of laterally-spaced apart, threaded apertures  28 L therein. Apertures  28 L extend from an upper surface of raised region  28 K through to bottom  28 B. A pair of set-screws  47  are threadably engaged in apertures  28 L and are rotated upwardly to bear against bottom  12 B of rail  12  and thereby to lock the latched rail stop  28  to rail  12 . The set screws  47  are rotated to the point that the position of rail stop  28  on rail  12  is substantially fixed, i.e., rail stop  28  does not tend to slide along rail  12  but rather remains in the same position. 
     Rail stop  28  further defines an opening  28 M in front  28 C. The opening  28 M extends inwardly toward rear  28 D. Opening  28 M is shaped to be complementary to boss  43 D on locking member  43 . A magnet  49  is seated within opening  28 M a distance inwardly from front  28 C of rail stop  28 . Alternatively, a ferromagnetic material may coat the interior surface of the opening  28 M if a magnet is provided as part of boss  43 D on locking member  43 . 
     In accordance with an aspect of the present disclosure, the overall shape of the second rail stop  28  is not symmetrical when the rail stop is viewed from the front as in  FIG. 8E . In particular, the second rail stop  28  includes a first region  28 N′ defined between groove  28 H and right side  28 F and includes a second region  28 N″ defined between groove  28 J and left side  28 E. Second region  28 N″ is substantially wider than first region  28 N′ where the widths are measured between the groove  28 H or  28 J and the associated side  28 F or  28 E, respectively. The height of first region  28 N′ and second region  28 N″ (as measured between top  28 A and bottom  28 B) is substantially the same. 
     It will be understood that each of the trolleys  22 ,  30 ,  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and  58  includes a body  27  and a plate  29  that are identical in structure and function to the body  27  and plate  29  of second trolley  26 . Furthermore, each of the trolleys  22 ,  30 ,  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and  58  includes an arm  33  that engages the plate  29  of that particular trolley and which further engages an associated rail stop in a similar manner to how the arm  33  of trolley  26  engages rail stop  28 . 
     The arms  33  on the trolleys  22 ,  26 ,  30 ,  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and  58  differ from each other in one or more ways. Firstly, the arm  33  may be engaged proximate the left side  29 E of the plate  29  of the particular trolley or the arm  33  may be engaged proximate the right side  29 F of the plate  29 . As illustrated in  FIGS. 1 and 2 , the trolleys  26 ,  34 ,  42 ,  50 , and  58  all have arms  33  engaged proximate left side  29 E of their plates  29 . The trolleys  22 ,  30 ,  38 ,  46 , and  54  all have their arm  33  engaged proximate the right side  29 F of their plates  29 . Consequently, the placement of the arm  33  alternates between the right side and left side of the plates  29  of the trolleys along the length of rail  12 . 
     Secondly, the length of the arm  33  on any particular trolley may be different from the length of the arm  33  on the adjacent trolleys. Additionally, the shape of the locking member  43  engaged with each arm  33  may be different from the shapes of the locking members  43  on adjacent trolleys. The different lengths of the arms  33  and shapes of the associated locking members  43  is varied so that one or more of the trolleys can slide past one or more of the rail stops so that the trolleys can be stacked. (This will be described later herein.) 
       FIGS. 8A-8F  each show a particular rail stop and the arm  33  associated therewith. In some instances, at least part of the locking member  43  that will engage that particular rail stop is illustrated.  FIG. 8A  shows the tenth rail stop  60  engaged with the arm  33  of the tenth trolley  58 .  FIG. 8B  shows the eighth rail stop  52  engaged with the arm  33  of the eighth trolley  50 .  FIG. 8C  shows the sixth rail stop  44  engaged with the arm  33  of the sixth trolley  42 .  FIG. 8D  shows the fourth rail stop  36  engaged with the arm  33  of the fourth trolley  34 .  FIG. 8E  shows the second rail stop  28  engaged with the arm  33  of the second trolley  26 .  FIG. 8F  shows the first rail stop  24 . As can be seen from  FIG. 1 , the arm  33  of first trolley  22  will be located on an opposite side of the first trolley  22  relative to the arms  33  shown in  FIGS. 8A-8E . If each of the rail stops and arms illustrated in  FIGS. 8A-8E  are rotated through 170 degrees, then those resultant rail stops and arms will be the ninth, seventh, fifth, third, and first rails stops and associated trolley arms, respectively. 
     As is evident from  FIGS. 6, 7, and 8A-8F , each rail stop includes a first region (identified by the number of the particular rail stop plus N′) and a second region (identified by the number of the particular rail stop plus N″). The first region s substantially identical across all of the illustrated rail stops  60 ,  52 ,  44 ,  36 ,  28 , and  24  but the second region thereof differs in one or more of height, width, and placement of the aperture that includes the locking magnet. In other words, the first regions  60 N′,  52 N′,  44 N′,  36 N′  28 N′, and  24 N′ are substantially identical in shape and size but the second regions  60 N″,  52 N″,  44 N″,  36 N″,  28 N″, and  24 N″ differ from each other. The particular shapes of the second regions and the placement of the magnet  43 D therein permit movement of the associated trolleys past each other as will be described later herein. In particular, the shape and size of the cooperating parts of the trollies and rail stops allows each trolley to move past all but one complementary rail stop. Additionally, the arrangement of the locking mechanisms (magnets) on the trollies and associated rail stops is laterally and/or vertically staggered relative to the remaining trollies and rail stops so that each trolley is able to move past all but one complementary rail stop. This aspect of the present disclosure will be described in greater detail hereafter. 
     Referring specifically to  FIG. 8A , tenth rail stop has a second region  60 N″ that is of a first width D 1  measured from a left side edge to a right side edge of the second region and perpendicular relative to these side edges. The width D 2  of second region  60 N″ is measured from the right side edge to a beginning of the opening  60 M that retains a magnet  49  therein. Width D 2  is less than the width D 1 . Second region  60 N″ also has a height H 1  measured from top  60 A to bottom  60 B. This figure also shows the arm  33  of tenth trolley  58  shown on its own with the locking member  43 , particularly the magnetic portion  43 D thereof, engaged in the opening  60 M of tenth rail stop  60 . The locking member  43  overlaps part of second region  60 N″ so that the opening  60 M is aligned with magnetic portion  43 D. In particular, the leg  33 B overlaps part of the width D 1  and part of the height H 1  of second region  60 N″. In this position, tenth trolley  58  is magnetically secured to tenth rail stop  60 . Leg  33  of tenth trolley is of a length L 1  measured from the bottom of the base  33 A to free end  33 G thereof. (It will be understood that the configuration of the rail stop and trolley leg illustrated in  FIG. 8A  is also used on ninth trolley  54  and ninth rail stop  56 , respectively, except the illustrated rail stop and leg will be rotated through 170 degrees. In other words, the first region of the ninth rail stop  56  will be longitudinally aligned with the second region  60 N″ of tenth rail stop  56 .) 
     Although not illustrated herein, it will be understood that tenth rail stop  60  is fixedly secured to rail  12  by set screws  47  ( FIG. 7 ) but tenth trolley  58  is movable in one of a first direction and a second direction along rail. The movement of tenth trolley  58  is substantially parallel to longitudinal axis “Y”. When tenth trolley  58  is to move toward front end  10 A ( FIG. 1 ) along rail  12 , the magnetic engagement between locking member  43  and magnet  49  must first be broken (as will be described later herein). Once the magnetic engagement is broken, tenth rail stop  60  remains in place on rail  12  but tenth trolley  58  moves toward ninth rail stop  52  and ninth trolley  50 . When tenth trolley  58  contacts ninth trolley  54 , the bumpers  39  will strike the back of the plate on ninth trolley  54  and impart motion to ninth trolley  54  in the direction towards front end  10 A. 
     Tenth trolley  58  is selectively able to move past ninth trolley  54  because only the first region of ninth rail stop  56  is engaged with rail  12  and that first region does not include any type of magnet to engage with locking member  43 . Additionally, the arm  33  on tenth trolley  58  is of an insufficient length to come into contact the first region of ninth rail stop  56 . Tenth trolley  58  will therefore readily move past ninth rail stop  56  and toward eighth rail stop  52  shown in  FIG. 8B . 
       FIG. 8B  shows the eighth rail stop  52  along with the arm of the eighth trolley  50 . The length of arm  33  on eighth trolley  50  is of the same length L 1  as the arm  33  on tenth trolley  58  ( FIG. 8A ). The second region  52 N″ of eighth rail stop  52  has a width D 3  that is less than the width D 2  of second region  60 N″ of tenth rail stop  60 . The opening  58 M that includes magnet  49  is defined in the second region  60 N″. The second region  52 N″ is of the same height H 1  as second region  60 N″ of tenth rail stop. As is evident from comparing  FIGS. 8A and 8B , the locking member  43 D of tenth trolley  58  will not align with the opening  58 M on eighth rail stop  52 . Additionally, the width D 3  is narrower than D 2  and so the tenth trolley is capable of moving past eighth rail stop  52  if sufficient force is applied to tenth trolley  58 . So, while the length L 1  of leg  33 B of tenth trolley  58  overlaps the height H 1  of second region  52 N″, that leg  33 B does not overlap the width D 3 . Consequently, leg  33 B of tenth trolley  58  is able to move past second region  52 N″ of eighth trolley  52 . 
       FIG. 8B  shows that the locking member  43 D of eighth trolley  50  will align with the opening  58 M in eighth rail stop  52 . It is therefore possible for eighth trolley  50  to be magnetically engaged with eighth rail stop  52 . It will be understood that the same configuration of the eighth rail stop  52  and arm  33  of eighth trolley  50  will be provided on seventh rail stop  48  and seventh trolley  46  except rotated through 170 degrees so that the arm is adjacent the right side  12 D of rail  12 . 
     If the ninth trolley  56  is caused to move toward front end  10 A by tenth trolley  60 , the bumpers  30  on ninth trolley  56  will in turn strike the rear of the plate of the eighth trolley  50  and break the magnetic connection between eighth trolley  50  and eighth rail stop  52 . The leg on the ninth trolley  56  is able to move past the first region  52 N′ of the eight rail stop  52 . If the eighth trolley  50  is caused to move toward front end  10 A, the leg  33 B of the eighth trolley  50  is able to move easily past the first region of the seventh rail stop  48  as there is no opening or magnet in the first region thereof. 
       FIG. 8C  shows the sixth rail stop  44  and six trolley leg  33 B. Second region  44 N″ of sixth rail stop  44  is of the same width D 1  as second region  60 N″ of tenth rail stop  60  ( FIG. 8A ) but is of a height H 2  from top  44 A to bottom  44 B that is shorter than the height H 1  of second region  60 N″ or second region  52 N″. The height H 2  of second region  44 N″ is low enough that a leg  33 B of length L 1  is able to pass over the top of second region  44 N″. Consequently, the legs  33 B of each of the tenth trolley  58  and the eighth trolley  50  will readily move over the top  44 A of second region  44 N″ and therefore their motion won&#39;t be impeded or halted by sixth rail stop  44 . 
       FIG. 8C  also shows the leg  33 B of the sixth trolley  42 . The leg  33 B of sixth trolley  42  is of a length L 2  as measured from the bottom of base  33 A to free end  33 G thereof. The length L 2  is longer than the length L 1 . The locking member  43  of sixth trolley  42  includes a magnetic portion that will overlap and be received in the opening  44 M defined in sixth rail stop  44 . Sixth rail stop  44 M is therefore able to magnetically retain sixth trolley  42  in engagement therewith. Fifth rail stop  40  and fifth trolley  38  will be similarly configured to sixth rail stop  44  and sixth trolley  42  but will be rotated through 170 degrees relative thereto. The tenth, ninth, eighth, seventh trolleys are able to move past both of the fifth and sixth rail stops  40 ,  42  because of the configuration of the legs  33 B and the second regions of the fifth and sixth rail stops  40 ,  42 . 
       FIG. 8D  shows the second region  36 N″ of the fourth rail stop  36  having a width D 3  that is identical to that of the second region  52 N″ of eighth rail stop  52 , and further having a height H 2  that is identical to that of the second region  44 N″ of sixth rail stop  44 . Comparing  FIGS. 8C and 8D , it can be seen that the leg  33 B of sixth trolley  42  will readily move past the fourth rail stop  36  because the position of the magnetic portion of the locking member  43  is laterally offset from the opening  36 M and magnet  49  provided on second region  36 N″ of sixth rail stop  36 . 
       FIG. 8D  further shows the leg  33 B of the fourth trolley  34  that is of the same length L 2  as the leg  33 B of the sixth trolley  42 , where length L 2  is measured from the bottom surface of the base  33 A to the tip  33 G of the sixth trolley&#39;s leg  33 B. The locking portion  43 D of the locking member  43  engaged with leg  33 B of the sixth trolley  34  is positioned to align with the opening  36 M and magnet  49  provided on fourth rail stop  36 . Fourth rail stop  36  is therefore able to arrest movement of fourth trolley  34  but will not arrest movement of the sixth trolley  34  because of the lateral offset between the magnetic locking portion  43 D on the sixth trolley&#39;s leg  33 B and the opening  36 M on the fourth rail stop  36 . It will be understood that the configuration of the third rail stop  32  and leg on the third trolley  30  will be substantially identical to the configuration of the fourth rail stop  36  and fourth trolley  34  except rotated through 170 degrees. As before, the third rail stop  32  will not impede the motion of any of the trolleys located rearwardly of it, i.e., trolleys  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and  58 . 
       FIG. 8E  shows the second rail stop  28  and leg  33 B of second trolley  26 . 
     Second region  28 N″ of second rail stop  28  is of the same width D 1  as second regions  60 N″ of tenth rail stop  60  and sixth rail stop  44  ( FIGS. 8A and 8C ) but is of a height H 3  that is shorter than the heights H 1  and H 2  of the previously described second regions. The height H 3  of second region  28 N″ is measured between the top  28 A and bottom  28 B of second region  28 N″. Height H 3  is low enough that a leg  33 B of length L 1  and a leg  33 B of length L 2  is able to pass over the top  28 A of second region  28 N″. Consequently, the legs  33 B of each of the trolleys located rearwardly of second trolley  26  will readily move over the top  28 A of second region  28 N″ and therefore their motion won&#39;t be impeded or halted by second rail stop  28 . In other words, trolleys  30 ,  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and  58  could readily move past second rail stop  28 . 
       FIG. 8E  also shows the leg  33 B of the second trolley  26 . The leg  33 B of second trolley  26  is of a length L 3  as measured from the bottom of base  33 A to free end  33 G thereof. The length L 3  is longer than the length L 1  and the length L 2 . The locking member  43  of second trolley  26  includes a magnetic portion that will overlap and be received in the opening  28 M defined in second rail stop  28  and become magnetically engaged with magnet  49  thereof. Second rail stop  28 M is therefore able to magnetically retain second trolley  26  in engagement therewith. First rail stop  24  is substantially identical to second rail stop  28  but is rotated through 170 degrees. First rail stop  24  (shown in  FIG. 8F ) presents a first region  24 N′ instead of a second region  24 N″ adjacent the left side  12 C of rail  12 . This first region  24 N′ is of a height H 4  measured between top  24 A and bottom  24 B. This height H 4  is lower than any of the heights H 1 , H 2 , and H 3 . The height H 4  is sufficiently low enough to allow a leg of lengths L 1  and L 2  and the location of the outermost side of the first region  24 N′ is located a distance D 4  that is short enough that the leg having a length L 3  are able to move past the same. First rail stop  24  therefore will not impede any of the trolleys two through ten, i.e., trolleys  26 ,  30 ,  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and  58 . 
     Referring to  FIGS. 9-15 ; the rotation mechanism  66  and translation mechanism  68  are shown in greater detail. Rotation mechanism  66  is provided to impart rotation to the lances  62  of system  10 , where each lance  62  is rotated about an axis that is parallel to longitudinal axis “Y”. Translation mechanism  68  is provided to impart linear motion to trolleys  22 - 58  along rail  12  in one of a first direction toward first end  10 A of system  10  and in a second direction toward second end  10 B thereof. 
       FIG. 9A  shows a left side view of ninth trolley  54 , ninth rail stop  56 , tenth trolley  58 , and tenth rail stop  60  engaged with rail  12 . Stacker  64  is shown positioned between upper edge  12 E of rail  12  and the lowermost lances  62 . It will be understood that the stacker  64  passes through a channel defined in each of ninth trolley  54  and tenth trolley  48 . The channel is substantially identical to channel  27 H ( FIG. 6 ) is aligned with similar channels in each of the first trolley  22  to the eighth trolley  50  and the channels  19 H of lance guide  20  and channel  13 H of transition guide  18 . As is evident from  FIGS. 1 and 2 , the lances  62  are located a distance above rail  12  and substantially parallel with each other until the lower lances  62  angle upwardly to pass through the openings  13   g  in transition guide  18 . After transition guide  18 , all of the lances are arranged in the same plane and extend through the tubes  13 D of end guide  16 . 
     Stacker  64  is operatively engaged with and extends forwardly from rotation mechanism  66  and is moved in unison therewith along rail  12 . Stacker  64  includes an elongated shaft  64 A that terminates in a tapered tip  64 B ( FIG. 10 ). The tip  64 B is located longitudinally remote from rotation mechanism  66 . A resilient, deformable puck  64 C is provided on shaft  64 A a distance rearwardly from tip  64 B. A second end of shaft  64 A is fixedly engaged with a pusher  64 D ( FIG. 9B ) operatively engaged with translation mechanism  66 . The purpose of stacker  64  will be described later herein. 
     Rotation mechanism  66  and translation mechanism  68  are mounted on a platform  70 . Platform  70  is a horizontally-oriented plate that has a plurality of horizontally-oriented wheels  70 A mounted a distance below a bottom surface thereof by fasteners  70 B. Wheels  70 A are substantially identical in structure and function to wheels  31  utilized on second trolley  26 . Wheels  70 A are therefore configured to operatively engage the associated upper edge  12 E of rail  12  and to enable the platform  70  and thereby the rotation mechanism  66  and translation mechanism  68  to move linearly along rail  12 . 
       FIGS. 9B, 11, and 12  show rotation mechanism  66  and translation mechanism  68  in greater detail. It should be understood that rotation mechanism  66  is shown diagrammatically in these figures. Rotation mechanism  66  includes a housing  66 A having an interior chamber  66 B ( FIGS. 12 and 13 ) within which at least a portion of several components are housed. The rotation mechanism  66  includes a set of motors  72 A and  72 B each having a drive shaft  72 C that is operatively engaged with a lance drive mechanism, generally indicated at  74 . Lance drive mechanism  74  shows diagrammatically a pair of drive members  74 A and a plurality of driven members  74 B. Each driven member  74 B is fixedly engaged with one of the lances  62 . The drive members  74 A are rotated by drive shafts  72 C about an axis that is oriented parallel to longitudinal axis “Y”. The drive members  74 A in turn rotate the driven members  74 B about another axis that is oriented parallel to longitudinal axis “Y”. As each driven member  74 B rotates, it causes rotational motion of the lance  62  with which that driven member is fixedly engaged. The drive members  74 A may comprise a drive chain or a drive belt, for example. The driven members  74 B may comprise a sprocket or gear (if the drive member is a drive chain) or a pulley (if the drive member is a drive belt). Any other suitable type of lance drive mechanism may be provided within rotation mechanism  66 . Support bearings  74 C are engaged with each of the lances  62  and extend outwardly from a front of housing  66 A. It will be understood that various other bushings or bearings (not numbered) are engaged with the drive shafts  72 C and other components of the lance drive mechanism  74  in order to ensure smooth rotation of the lances  62 . Each of the two motors  72 A,  72 B drives one of the driven members  74 A. 
     As can be seen in  FIG. 13 , each of the drive members  74 A is operatively engaged with three of driven members  74 B which are engaged with the lances  62 . One of the driven members, identified by the reference character  74 B′ is rotated by both of the drive members  74 A. The drive members  74 A overlap each other as they are both engaged with driven member  74 B′ and because of this, all lances  62  will rotate in unison. 
     A rear end of each lance  62  is operatively engaged with a swivel  75  that is, in turn, operatively engaged with a splitter assembly  76  ( FIGS. 11 and 12 ) via feed lines  78 . An inlet pipe  80  is operatively engaged with splitter assembly  76  at one end and is connected to a remote fluid supply at the other end. The remote fluid supply may provide a liquid or gas to splitter assembly  76 . The liquid or gas is supplied to the lances  62  from splitter assembly  76  via the swivels  75 . Swivels  75  rotate in unison with the associated lances  62  and are internally configured to enable the liquid or gas to flow steadily into lances from splitter assembly  76 . It should be noted that the remote fluid supply is preferably a source  82  ( FIG. 12 ) of high pressure liquid or gas. The lances  62  pass through the various openings  27 G in the trolleys  22 - 58 , openings  19 G in lance guide  20 , openings  13 G in transition guide  18 , and through tubes  16 D of end guide  16  and the terminal ends of the lances  62 , which typically will include a nozzle exit from the nosepieces  16 F ( FIG. 3 ). The high pressure fluid flows through the bore of each lance and exits therefrom through the nozzles at the terminal ends thereof. 
     Translational mechanism  68  is located longitudinally rearwardly from rotation mechanism  66  on platform  70 . Translation mechanism  68  includes a housing  68 A that defines an interior chamber  68 B ( FIG. 15 ) that housing a drive gear  68 C therein. Drive gear  68 C is operatively engaged with a motor  84  via a drive shaft  84 A. When motor  84  is actuated, drive shaft  84 A rotates about an axis that extends along the drive shaft  84 A and turns drive gar  68 C about that axis. The axis about which drive gear  68 C rotates is oriented at right angles to longitudinal axis “Y”. Housing  68 A is mounted on platform  70  and an opening  70 C ( FIG. 15 ) is defined in the platform  70  in a location that falls directly above the track  12 H on rail  12  and below housing  68 A. More specifically, the opening  70 C permits a portion of drive gear  68 C to extend downwardly below a bottom surface of platform  70  and engage track  12 H. Drive gear  68 C includes a plurality of teeth  68 D thereon that are configured and spaced to engage in the apertures that form track  12 H. 
     When drive gear  68 C is rotated about the axis along drive shaft  84 A in a first direction, the engagement of teeth  68 D and apertures  12 H cause drive shaft  68 C to advance down track  12 H in a first direction toward front end  10 A of system  10 . When drive gear  68 C is rotated in the opposite direction, the interlocking engagement of teeth  68 D and apertures  12 H result in drive gear advancing in the second direction toward rear end  10 B of system  10 . Because drive gear  68 C is operatively engaged with platform  70 , when drive gear  68 C advances along track  12 H in the first direction, the platform  70  also moves along rail  12  in the first direction. Wheels  70 A on platform  70  ride along upper edge  12 E of rail  12 . If platform  70  moves in the first direction along rail  12 , then rotation mechanism  66  also moves in unison therewith in the first direction. Since stacker  64  is operatively engaged with rotation mechanism  66 /translation mechanism  68  and thereby with platform  70 , as platform  70  moves in the first direction, stacker  64  also moves in the first direction. 
     As platform  70  advances toward front end  10 A, the tip  64 B of stacker  64  advances through the channel  27 H in tenth trolley  58  and pusher  64  ultimately contacts a rear end  29 D of the plate  29  of the tenth trolley  58 . As drive gear  68 C continues to rotate, sufficient force is applied to plate  29  of the tenth trolley  58  by the translation mechanism  68  to break the magnetic engagement of tenth trolley  58  with the tenth rail stop  60  and tenth trolley  58  starts to move linearly along rail  12  in the first direction. 
     It will be understood that if the drive gear  68 B is rotated in the opposite direction, the platform  70  will be moved in the second direction along the rail  12  and therefore the trolleys are able to move linearly in the second direction along rail  12 . 
     It will be understood that the motors  72 A,  72 B and  84  may be driven by one or more of water, air, electricity, magnetism, and electromagnetism. 
     Having thus described an exemplary non-limiting configuration of the system  10 , the system&#39;s operation will be discussed hereafter with reference particularly to  FIGS. 16-23 . 
       FIG. 16  shows the system  10  positioned adjacent a heat exchanger  104  that is to be cleaned and ready to perform a cleaning operation on tubes of the heat exchanger. Heat exchanger  104  includes a tube bundle that is located within a housing  104 A ( FIGS. 16 and 17 ) engaged with a support  104 B and retained a distance above the ground “G”. The housing  104 A terminates in an end plate  104 C which defines a plurality of openings  104 D therein. Each opening  104 D is aligned with a bore of one of the heat exchanger tubes that forms part of the tube bundle retained within the housing  104 A. 
     Referring to  FIGS. 16 and 16A , system  10  is supported in position proximate end plate  104 C by support frame  11  and indexer  14 . The end guide  16  extends forwardly and outwardly beyond a front end  14 E of indexer  14  so that the nosepieces  16 F of end guide  16  form a leading end of the system  10 . The rest of the system  10  extends rearwardly from the rear surface  14 B of indexer  14 . The rear end  10 B of system  10  is suspended from support frame  11  by suspension rod  11 D so that the indexer  14  may perform its functions properly. Indexer  14  itself may be locked into position on ground “G” using locking mechanisms  14 C. Locking mechanisms  14 C help to either prevent the wheels  14 B of indexer moving across the ground “G” or lifting the wheels  14 B off the ground and thereby preventing the shifting of system  10  relative to end plate  104 C of indexer  14 . The indexer  14  may be utilized to move system  10  in any desired direction relative to end plate  104 C and along one or both of a vertical axis and a horizontal axis relative thereto. In particular, the indexer may be utilized to position nosepieces  16 F in close proximity to a set of aligned openings  104 D in end plate  104 C. Since system  10  includes five lances  62 , indexer  14  may be utilized to position the five nosepieces  16 F and thereby the five terminal ends of the lances  62  immediately adjacent five openings  104 D in end plate  104 C. Indexer  14  positions nosepieces  16 F by moving the front end  10 A of system  10  up, down, to the left, to the right, along a diagonal or at an angle relative to the horizontal and vertical axes. 
     At the start of a tube cleaning operation ( FIG. 16 ), platform  70  with translation mechanism  68  and rotation mechanism  66  thereon is located proximate the second end of the rail  12  (i.e., proximate second end  10 B) and proximate support frame  11 . The trolleys  22 - 58  are generally equidistantly spaced from each other along rail  12  and stacker  64  is in its at-rest position where the tip  64 B is located somewhere between eighth trolley  50  and the ninth trolley  54 . It will be understood that stacker shaft  64 A is already extending through the channel  27 H of ninth and tenth trollies  54 ,  58  and is poised to pass into the channel  27 H of the eighth trolley  50  as is shown in  FIG. 17A  but the puck  64 C has not yet entered channel  27 H of the ninth trolley  54 . As is evident from  FIG. 17A , puck  64 C on stacker  64  is in a non-deformed state. It will be understood that puck  64 C is positioned between front  27 C of tenth trolley  58  and back  27 D of ninth trolley  54 . It will be understood that in other applications, the tip  64 B of stacker  64  may be located between the ninth trolley  54  and tenth trolley  58  before a cleaning operation begins or between any other trolleys of system  10 . The stacker  64  may also be of any length suitable to permit the puck  64 C to pass out of the channel  27 H of the first trolley  22  regardless of the number of trolleys utilized in system  10 . 
     Prior to actuation, all the trolleys  22 - 58  are magnetically engaged with their respective rail stops  24 - 60 . The distance between end plate  104 C of heat exchanger and a front end of the platform  70  is indicated in  FIG. 16  as distance R 1 . The cleaning operation is started when high pressure fluid is provided to system  10  via inlet pipe  80 . In the exemplary embodiment, the high pressure fluid is water. Specifically, high pressure fluid will move from the remote fluid source  82  through the inlet pipe  80 , enters inputs  76 A ( FIG. 12 ) of the splitter  76 , flows from the splitter through feed tubes  78  and is subsequently outputted from the feed tubes and into the inputs  75 A of swivels  75 . From the swivels  75 , the fluid flows into the bores of the plurality of lances  62 . Lance drive mechanism  74  is then activated by actuating first and second motors  72 A,  72 B. Motors  72 A,  72 B rotate the two drive members  74 A which in turn cause driven members  74 B to rotate. In particular, the rotating chain or belt  74 A engaged with the sprockets or pulleys  74 B causes the sprockets or pulleys  74 B to rotate. Since lance supports  74 C are operatively engaged with the sprockets or pulleys  74 B, rotation of the sprockets or pulleys  74 B causes rotation of the lance supports  74 C and thereby of the lances  62  engaged therewith. Each lance  62  has a nozzle at its end, so rotation of the lance  62  causes rotation of the associated nozzle and therefore rotation of the stream of fluid flowing out of the nozzle. 
     Substantially simultaneously with the actuation of motors  72 A,  72 B, the operator will actuate moto  84  to activate the translation mechanism  68 . As has been described earlier herein, the motor  84  of translation mechanism  68  will rotate the drive gear  68 C in the direction “A” ( FIG. 15 ) and the drive gear  68 C will then move linearly down the track  12 H in a first direction “B” ( FIGS. 15 and 18A ) towards front end  10 A and thereby towards end plate  104 C. As drive gear  68 C rotates it causes the platform  70  to begin to move in the direction “B” away from rear end  10 B and therefore away from the second end of rail  12 . The platform  70  moves toward and ultimately contacts tenth trolley  58 , as will be described hereafter. Because the lances  62  extend outwardly from rotation mechanism  66 , linear movement of the platform  70  will also cause linear movement of the lances  62  in the same direction. The terminal ends of the lances  62  and nozzles thereon will emerge from the nosepieces  16 F of end piece  16  and will enter the openings  104 D with which the nosepieces  16 F are aligned. High pressure fluid exiting the nozzles on the lances  62  will scour away build-up on the interior surface the tube. The rotation of the lances  62  helps to ensure that the circumferential interior surfaces of the heat exchanger tubes are thoroughly cleaned by the high pressure fluid. 
     Because the heat exchanger tubes may be quite long, the lances  62  need to advance further into the bores of the tubes to ensure that the tubes are thoroughly cleaned. In order to advance the lances  62  further into the tube bores, translation mechanism  68  continues to operate to advance platform  70  toward heat exchanger  104 . Referring to  FIG. 18A - FIG. 20 , when the platform  70  moves down the track  12 H from the rear end  10 B toward the front end  10 A in the direction “B”, the pusher  64 D ( FIG. 9B ) on platform  70  makes contact with the rear  29 D ( FIG. 7 ) of the plate  29  of tenth trolley  58 . This contact is operative to dislodge the magnetic boss  43 D on tenth trolley  58  from the opening  60 M ( FIG. 8A ) of tenth rail stop  60 . As drive gear  68 C continues to rotate, the platform  70  and tenth trolley  58  continue to move in the direction of arrow “B” because the wheels  70 B of platform  70  and wheels  31  of tenth trolley  58  ride along upper edge  12 E. 
     Pusher  64 D forces tenth trolley  58  forwardly in the direction of arrow “B” and, substantially simultaneously, stacker  64  itself moves in the direction arrow “B” and tip  64 B thereof moves through the channel  27 H of ninth trolley until puck  64 C contacts a region of back  27 D of ninth trolley  54  and applies force thereto. Continued forward motion of platform  70  and therefore of stacker  64  will cause shaft  64 A of stacker and the puck  64 C engaged therewith through channel  27 H. Puck  64 C deforms as shown in  FIG. 17B  until the puck  64 C reaches front  27 C of ninth trolley  54  and exits channel  27 H. Puck  64 C then returns to its non-deformed stated as shown in  FIG. 17C . 
     Ultimately, the bumpers  39  on the moving tenth trolley  58  contact the rear  29 D of the plate of ninth trolley  54 . As the drive gear  68 C continues to rotate, the force applied by the advancing platform  70  and the tenth trolley  58  is sufficient to break the magnetic engagement of boss  43 D on ninth trolley  56  with the associated magnet on the ninth rail stop  56  and the ninth trolley  54  will begin to move linearly along rail  12  towards front end  10 A. The tenth trolley  58  is able to easily pass over the ninth rail stop  56  because most of the ninth rail stop  56  is on the right side  12 D of the rail and the arm  33  of the tenth trolley  58  is on the left side  12 C of the rail  12 . The portion of the ninth rail stop  56  that is on the left side  12 C of the rail  12  is too short to contact arm  33  of tenth trolley  58 . There is furthermore no part of the tenth trolley  58  that extends downwardly and contacts any part of the ninth rail stop  56  on the right side  12 D of rail  12 . 
     As platform  70  continues to advance in the direction “B”, the ninth trolley  54 , (and the tenth trolley  58  which is retained with ninth trolley  54  on stacker  64 ) advances toward eighth trolley  50  and the associated eighth rail stop  52 . The wheels  31  of ninth trolley  54  help to ensure smooth travel of ninth trolley  54  along rail  12 . As ninth trolley  54  approaches eighth trolley  50 , the tip  64 B of the stacker  64  will begin to pass through the channel  27 H of eighth trolley  50  and the puck  64 C will deform as it enters channel  27 H and then return to its original shape once puck  64 C moves outwardly from channel  27 H. (The deformation and then return of puck  64 C to its original shape occurs every time a new trolley is engaged on stacker  64 .) Bumpers  39  of ninth trolley  54  contact rear  29 D of the plate  29  on eighth trolley  50 . As a result of the contact, the magnetic attraction between the magnetic boss  43 D on eighth trolley  50  and the magnet  49  on eighth rail stop  52  is broken and eighth trolley  50  begins to move in the direction “B”. This situation is shown in  FIG. 18A . Wheels  31  on eighth trolley  50  are operative to move along the edges  12 E of the rail  12  and tip  64 B of stacker  64  will pass through the channel  27 H of the eighth trolley  50 . Since the arm  33  of the ninth trolley  54  is located adjacent the right side  12 D of rail  12 , no part of the ninth trolley  54  extends downwardly to contact the eighth rail stop  52  which is located adjacent left side  12 C of rail  12 . Consequently, ninth trolley  54  moves easily past eighth rail stop  52 . 
     The arm  33  of tenth trolley  58  is located adjacent left side  12 C of rail  12  and does extend downwardly to the point that it might look as if the eighth rail stop  52  might impede the movement of tenth trolley  58 . However, as is illustrated in  FIG. 19A  and has been discussed earlier herein with respect to  FIG. 8B ), the shape and width of the second region  52 N″ is such that arm  33  of tenth trolley  58  does not actually come into contact with second region  52 N″. Tenth trolley  58  is therefore able to move unimpeded past eighth rail stop  52 . 
       FIG. 18A  also shows that tenth trolley  58 , ninth trolley  54 , and eighth trolley  50  have become stacked upon the stacker  64  and the spacing between these stacked trolleys has been substantially reduced relative to the initial spacing therebetween shown in  FIG. 16 . Additionally, the distance between the nosepieces  16 F and the front of platform  70  has been reduced from a distance R 1  to a distance R 2 . The actual length of the lances  62  has not been reduced but, instead, a length of R 1 -R 2  of the lances  62  has been advanced into the bores of the tubes in the heat exchanger. 
     As drive gear  68 C continues to advance along track  12 H toward front end  10 A of system  10 , eighth trolley  50  (along with tenth and ninth trolleys  58 ,  54  on stacker  64 ) moves forwardly in the direction of arrow “B” until bumpers  39  on eighth trolley  50  make contact with rear  29 D of plate  29  on seventh trolley  46 . As a result of this contact, the magnetic attraction between the magnetic boss  43 D on seventh trolley  46  and the magnet  49  on seventh rail stop  48  is broken and seventh trolley  46  begins to move in the direction of arrow “B”. Wheels  31  on seventh trolley  46  are operative to move along the edges  12 E of the rail  12  and tip  64 B of stacker  64  will pass through the channel  27 H of the seventh trolley  46 . Since the arm  33  of the eighth trolley  50  is located adjacent the left side  12 C of rail  12 , no part of the eighth trolley  50  extends downwardly to contact the seventh rail stop  48  which is located adjacent right side  12 D of rail  12 . Consequently, eighth trolley  54  moves easily past seventh rail stop  48 . As described earlier herein with respect to  FIGS. 8A-8F , all of the trollies located rearwardly of the eighth trolley  50 , i.e., trollies  58  and  54  are also able to readily move past seventh rail stop  48 . 
     Wheels  31  on seventh trolley  46  help the trolley to move along rail  12  in the direction of arrow “B” toward sixth trolley  42  and sixth rail stop  44  until bumpers  39  on seventh trolley  46  contact rear  29 D of the plate  29  of sixth trolley  42 . As seventh trolley  46  approaches sixth trolley  44 , the tip  64 B of the stacker  64  will begin to pass through the channel  27 H of sixth trolley  44 . (It should be noted that all of the tenth trolley  58 , ninth trolley  54 , eighth trolley  50 , and seventh trolley  46  are carried on the shaft  64 A of stacker  64  and moved in unison with platform  70  as it moves toward front end  10 A.) As a result of the contact between bumpers  39  of seventh trolley  46  and plate  29  of sixth trolley  42 , the magnetic attraction between the magnetic boss  43 D on sixth trolley  42  and the magnet  49  on sixth rail stop  44  is broken and sixth trolley  42  begins to move in the direction “B”. This situation is shown in  FIG. 18B . Since the arm  33  of the seventh trolley  46  is located adjacent the right side  12 D of rail  12 , no part of the seventh trolley  46  extends downwardly to contact the sixth rail stop  42  which is located adjacent left side  12 C of rail  12 . Consequently, seventh trolley  46  moves easily past sixth rail stop  42 . 
     The arm  33  of eighth trolley  50  is located adjacent left side  12 C of rail  12  and does extend downwardly to the point that it might look as if the sixth rail stop  44  might impede the movement of eighth trolley  50 . However, as is illustrated in  FIG. 19B  and has been discussed earlier herein with respect to  FIG. 8C ), the shape and width of the second region  44 N″ is such that arm  33  of eighth trolley  50  does not actually come into contact with second region  44 N″. Eighth trolley  50  and both of the ninth trolley  54  and tenth trolley  58  are therefore able to move unimpeded past sixth rail stop  44 . 
       FIG. 18B  also shows that tenth trolley  58 , ninth trolley  54 , eighth trolley  50 , seventh trolley  46 , and the sixth trolley  46  have become stacked upon the stacker  64  and the spacing between these stacked trolleys has been substantially reduced relative to the initial spacing therebetween shown in  FIG. 16 . Additionally, the distance between the nosepieces  16 F and the front of platform  70  has been further reduced from the distance R 2  to a distance R 3 . Again, the length of the lances  62  has not been reduced but, instead, a length of R 1 -R 3  of the lances  62  has been advanced in the direction “B” into the bores of the tubes in the heat exchanger  104 . 
     As drive gear  68 C continues to advance along track  12 H toward front end  10 A of system  10 , sixth trolley  46  (and all the rest of the trolleys stacked on stacker  64 ) moves forwardly in the direction of arrow “B” until bumpers  39  on sixth trolley  46  make contact with rear  29 D of plate  29  on fifth trolley  38 . As a result of this contact, the magnetic attraction between the magnetic boss  43 D on fifth trolley  38  and the magnet  49  on fifth rail stop  40  is broken and fifth trolley  38  begins to move in the direction of arrow “B”. Wheels  31  on fifth trolley  38  are operative to move along the edges  12 E of the rail  12  and tip  64 B of stacker  64  will pass through the channel  27 H of the fifth trolley  38 . Since the arm  33  of the sixth trolley  50  is located adjacent the left side  12 C of rail  12 , no part of the sixth trolley  50  extends downwardly to contact the fifth rail stop  40  which is located adjacent right side  12 D of rail  12 . Consequently, sixth trolley  42  moves easily past fifth rail stop  40 . As described earlier herein with respect to  FIGS. 8A-8F , all of the trollies located rearwardly of the sixth trolley  50  are also able to readily move past fifth rail stop  40 . 
     Wheels  31  on fifth trolley  38  help the trolley to move along rail  12  in the direction of arrow “B” toward fourth trolley  34  and fourth rail stop  36  until bumpers  39  on fifth trolley  38  contact rear  29 D of the plate  29  of fourth trolley  34 . As fifth trolley  38  approaches fourth trolley  34 , the tip  64 B of the stacker  64  will begin to pass through the channel  27 H of fourth trolley  34 . (It should be noted that all of the tenth trolley  58 , ninth trolley  54 , eighth trolley  50 , seventh trolley  46 , sixth trolley  42 , and fifth trolley  38  are carried on the shaft  64 A of stacker  64  as platform  70  moves toward front end  10 A.) As a result of the contact between bumpers  39  of fifth trolley  38  and plate  29  of fourth trolley  34 , the magnetic attraction between the magnetic boss  43 D on fourth trolley  34  and the magnet  49  on fourth rail stop  36  is broken and fourth trolley  34  begins to move in the direction “B”. This situation is shown in  FIG. 18C . Since the arm  33  of the fifth trolley  38  is located adjacent the right side  12 D of rail  12 , no part of the fifth trolley  38  extends downwardly to contact the fourth rail stop  36  which is located adjacent left side  12 C of rail  12 . Consequently, fifth trolley  38  moves easily past fourth rail stop  36 . 
     The arm  33  of sixth trolley  42  is located adjacent left side  12 C of rail  12  and does extend downwardly to the point that it might look as if the fourth rail stop  36  might impede the movement of sixth trolley  42 . However, as is illustrated in  FIG. 19C  and has been discussed earlier herein with respect to  FIG. 8D ), the shape and width of the second region  36 N″ is such that arm  33  of sixth trolley  50  does not actually come into contact with second region  36 N″. Sixth trolley  42  and all the trollies located rearwardly thereof to the tenth trolley  58  are therefore able to move unimpeded past fourth rail stop  36 . 
       FIG. 18C  also shows that tenth trolley  58 , ninth trolley  54 , eighth trolley  50 , seventh trolley  46 , the sixth trolley  46 , fifth trolley  38 , and fourth trolley  34  have become stacked upon the stacker  64  and the spacing between these stacked trolleys has been substantially reduced relative to the initial spacing therebetween shown in  FIG. 16 . Additionally, the distance between the nosepieces  16 F and the front of platform  70  has been further reduced from the distance R 3  to a distance R 4 . Again, the length of the lances  62  has not been reduced but, instead, a length of R 1 -R 4  of the lances  62  has been advanced in the direction “B” into the bores of the tubes in the heat exchanger  104 . 
     As drive gear  68 C continues to advance along track  12 H toward front end  10 A of system  10 , fourth trolley  34  (and all the rest of the trolleys stacked on stacker  64 ) moves forwardly in the direction of arrow “B” until bumpers  39  on fourth trolley  34  make contact with rear  29 D of plate  29  on third trolley  30 . As a result of this contact, the magnetic attraction between the magnetic boss  43 D on third trolley  30  and the magnet  49  on third rail stop  32  is broken and third trolley  30  begins to move in the direction of arrow “B”. Wheels  31  on third trolley  30  are operative to move along the edges  12 E of the rail  12  and tip  64 B of stacker  64  will pass through the channel  27 H of the third trolley  30 . Since the arm  33  of the fourth trolley  34  is located adjacent the left side  12 C of rail  12 , no part of the fourth trolley  34  extends downwardly to contact the third rail stop  32  which is located adjacent right side  12 D of rail  12 . Consequently, fourth trolley  34  moves easily past third rail stop  32 . As described earlier herein with respect to  FIGS. 8A-8F , all of the trollies located rearwardly of the fourth trolley  34  are also able to readily move past third rail stop  32 . 
     Wheels  31  on third trolley  30  help the trolley to move along rail  12  in the direction of arrow “B” toward second trolley  26  and second rail stop  28  until bumpers  39  on third trolley  30  contact rear  29 D of the plate  29  of second trolley  26 . As third trolley  30  approaches second trolley  26 , the tip  64 B of the stacker  64  will begin to pass through the channel  27 H of second trolley  26 . (It should be noted that all of the tenth trolley  58 , ninth trolley  54 , eighth trolley  50 , seventh trolley  46 , sixth trolley  42 , fifth trolley  38 , fourth trolley  34 , and third trolley  30  are carried on the shaft  64 A of stacker  64  as platform  70  moves toward front end  10 A.) As a result of the contact between bumpers  39  of third trolley  30  and plate  29  of second trolley  26 , the magnetic attraction between the magnetic boss  43 D on second trolley  26  and the magnet  49  on second rail stop  28  is broken and second trolley  26  begins to move in the direction “B”. This situation is shown in  FIG. 18D . Since the arm  33  of the third trolley  30  is located adjacent the right side  12 D of rail  12 , no part of the third trolley  30  extends downwardly to contact the second rail stop  28  which is located adjacent left side  12 C of rail  12 . Consequently, third trolley  30  moves easily past second rail stop  28 . 
     The arm  33  of fourth trolley  34  is located adjacent left side  12 C of rail  12  and does extend downwardly to the point that it might look as if the second rail stop  28  might impede the movement of fourth trolley  34 . However, as is illustrated in  FIG. 19D  and has been discussed earlier herein with respect to  FIG. 8E ), the shape and width of the second region  28 N″ is such that arm  33  of fourth trolley  34  does not actually come into contact with second region  28 N″. Fourth trolley  34  and all the trollies located rearwardly thereof to the tenth trolley  58  are therefore able to move unimpeded past second rail stop  28 . 
       FIG. 18D  also shows that tenth trolley  58 , ninth trolley  54 , eighth trolley  50 , seventh trolley  46 , sixth trolley  46 , fifth trolley  38 , fourth trolley  34 , third trolley  30 , and second trolley  26  have become stacked upon the stacker  64  and the spacing between these stacked trolleys has been substantially reduced relative to the initial spacing therebetween shown in  FIG. 16 . Additionally, the distance between the nosepieces  16 F and the front of platform  70  has been further reduced from the distance R 4  to a distance R 5 . Again, the length of the lances  62  has not been reduced but, instead, a length of R 1 -R 5  of the lances  62  has been advanced in the direction “B” into the bores of the tubes in the heat exchanger  104 . 
     As drive gear  68 C continues to advance along track  12 H toward front end  10 A of system  10 , second trolley  26  (and all the rest of the trolleys stacked on stacker  64 ) moves forwardly in the direction of arrow “B” until bumpers  39  on second trolley  26  make contact with rear  29 D of plate  29  on first trolley  22 . As a result of this contact, the magnetic attraction between the magnetic boss  43 D on first trolley  22  and the magnet  49  on first rail stop  24  is broken and first trolley  22  begins to move in the direction of arrow “B” and towards lance guide  20 . Wheels  31  on first trolley  22  are operative to move along the edges  12 E of the rail  12  and tip  64 B of stacker  64  will pass through the channel  27 H of the first trolley  22 . Since the arm  33  of the second trolley  26  is located adjacent the left side  12 C of rail  12 , no part of the second trolley  26  extends downwardly to contact the first rail stop  24  which is located adjacent right side  12 D of rail  12 . Consequently, second trolley  26  moves easily past first rail stop  24 . As described earlier herein with respect to  FIGS. 8A-8F , all of the trollies located rearwardly of the second trolley  26  are also able to readily move past first rail stop  24 . 
       FIG. 18E  shows that all of the trolleys  22 - 58  are engaged on stacker  64  and that the first trolley  22  is located a distance rearwardly from lance guide  20 . Additionally, the distance between the nosepieces  16 F and the front of platform  70  has been further reduced from the distance R 5  to a distance R 6 . Again, the length of the lances  62  has not been reduced but, instead, a length of R 1 -R 6  of the lances  62  has been advanced in the direction “B” into the bores of the tubes in the heat exchanger  104 . 
       FIG. 19E  shows why the second trolley  26  is able to move past the first rail stop  24 . As is evident from this figures, the first region  24 N′ of the first rail stop  24  is located adjacent the left side  12 C of rail  12 . Arm  33  of second trolley  26  is laterally spaced from first region  24 N′ and therefore the first region  24 N′ cannot impede the forward movement of second trolley  26  past first rail stop  24 . Additionally, the figure shows that the second region  24 N″ of first rail stop  24  which includes the magnet  49 , is nowhere near where it needs to be to magnetically engage the magnetic boss on locking member  43  of second trolley  26 . 
     As drive gear  68 C continues to advance along track  12 H toward front end  10 A of system  10 , first trolley  22  (and all the rest of the trolleys stacked on stacker  64 ) moves forwardly in the direction of arrow “B” until bumpers  39  on first trolley  26  make contact with rear  29 D of plate  29  on lance guide  20 . As a result of this contact all forward motion in the direction of arrow “B” ( FIG. 18F ) is halted. The tip  64 B of stacker  64  moves through the channel  19 H of lance guide  20 . All of the trolleys  22 - 58  are stacked on stacker  64  and are retained between lance guide  20  and rotation mechanism  6  as can be seen in  FIG. 20 . Through the movement of first trolley  22  forwardly toward lance guide  20 , the distance between the nosepieces  16 F and the front of platform  70  has been further reduced from the distance R 6  to a distance R 7 . Again, the length of the lances  62  has not been reduced but, instead, a length of R 1 -R 7  of the lances  62  has been advanced in the direction “B” into the bores of the tubes in the heat exchanger  104 . This is the maximum length of the lances  62  that can be inserted into the tube bores. As will be evident from this description, throughout the entire process of inserting a set of long-length lances  62  into the heat exchanger tubes, the lances  62  have been well supported and have not been inadvertently bent or curved while doing so. Additionally, the lances  62  have been well supported while performing a cleaning operation as they are inserted into the tubes of heat exchanger  104 . 
     After fully inserting lances  62  entirely into the heat exchanger  104  and properly cleaning the elongated tubes therein, it may be desired to clean additional tubes of the heat exchanger  104 . In order to do this the lances  62  must be retracted back into their original position (shown in  FIG. 16 ). This occurs by reversing the process described above. To begin the reverse movement of the lances, i.e., in the direction of arrow “C” in  FIGS. 21-23 , the translation mechanism  68  must be actuated to cause the lances  62  and trollies  22 - 58  to be moved in the direction of arrow “C”. This is accomplished by reversing the direction of rotation of drive shaft  84 A and thereby the rotation of drive gear  68 C. In other words, referring to  FIG. 15 , drive gear  68 C is rotated in the opposite direction to arrow “A”. The rotation of drive gear  68 C in the opposite direction to arrow “A” causes the drive gear  68 C to move along track  12 H towards rear end  10 B of system  10  and away from nosepieces  16 F. As drive gear  68 C moves in the direction “C” along track  12 H, platform  70  is moved in the direction “C”. Because stacker  64  is operatively engaged with translation mechanism  66  and platform  70 , as translation mechanism  66  moves in the direction of arrow “C”, stacker  64  is also moved in the direction of arrow “C”. 
     As is shown in  FIGS. 21-23 , stacker  64  is provided with a deformable member (puck  64 C) causes the trollies  22 - 58  to be moved rearwardly in response to the movement of platform  70  and thereby of stacker  64 . Referring now to  FIG. 21 , the platform  70  (not shown) has begun retracing along the track  12 H toward the rear end  10 B of the system  10 . (It will be understood that some of the lances  62  are only partially shown for clarity of illustration.) Stacker  64  has begun to move rearwardly in the direction of arrow “C” and away from lance guide  20 . Puck  64 C on stacker  64  is of a greater diameter than the width of channel  27 H defined in first trolley  22  ( FIG. 22A ). Because of this, puck  64 C initially cannot enter channel  27 H but instead abuts regions of the front  27 C of the trolley body  27  of first trolley  22 . As stacker  64  continues to move rearwardly, the trollies  22 - 58  carried on stacker  64  are caused to move with the stacker because the puck  64 C is pulling the first trolley  22  rearwardly with it. 
     The rear movement of the trollies  22 - 58  continues until first trolley  22  comes into contact with the first rail stop  24 . The magnetic boss  43 D on first trolley  22  will be received within the aligned opening  22 M ( FIG. 19E ) and magnet  49  on first rail stop  24  and the rearward movement of first trolley  22  will be arrested. Because the drive gear  68 C continues to move rearwardly and the platform  70  and therefore the stacker  64  continue to move rearward in the direction of arrow “C”, eventually the force applied to the puck by the rearward motion of the stacker  64  will cause the puck  64 C to deform and enter into the channel  27 H of first trolley  22 . The deformed puck  64 C traveling through the channel  27 H is shown in  FIG. 22B . The continued rearward motion will eventually pull puck  64 C out of channel  27 H of first trolley  22  as shown in  FIG. 22C . As rearward motion of translation mechanism  66  continues, the puck  64 C will come into contact with regions of the front  27  of second trolley  26  and will begin to drag the second trolley  26  to tenth trolley  58  carried on the stacker  64  rearwardly with it. First trolley  22  remains in magnetic engagement with first rail stop  24  in the position shown in  FIGS. 16 and 23 . 
     Continued rearward movement of stacker  64  in response to the action of translation mechanism  66  will move the stack of trollies  26 - 58  toward the second rail stop  28  ( FIG. 23 ). When second trolley  26  reaches the second rail stop  28 , the magnetic boss  43 D on locking member  43  on second trolley  26  will align with the opening  28 M and magnet  49  on second rail stop  28  ( FIG. 8E ) and the second trolley  26  will become magnetically engaged with second rail stop  28 . The rearward motion of second trolley  26  will therefore cease. Puck  64 C will deform and travel through the channel  27 H of second trolley  26 , exit the channel and come into abutting contact with third trolley  30  and repeat the process described above. Each trolley  22 - 58  will therefore sequentially become re-engaged with the complementary rail stop and ultimately the system  10  will be in the configuration shown in  FIG. 16 . The indexer  14  will be actuated to shift nosepieces  16 F to align with different openings  104 D in end plate  104 C of heat exchanger  104 , and the process described herein will be repeated until all tubes in the heat exchanger have been cleaned by the high power water jets issuing from the nozzles of the lances  62 . 
     It will be understood that the indexing process may be controlled electronically by a suitable control system such as THE LUNCHBOX® created by Terydon Incorporated of Navarre, Ohio, USA. This program allows an operator to position himself or herself a distance away from the end plate  104 C of the heat exchanger and safely move the lances  62  into and out of the openings  104 D in the end plate and clean the tube bores aligned therewith with high pressure fluid. 
     While the embodiment described herein describes ten trollies with ten staggered rail stop apertures, further embodiments may provide for as few as one and as many as two hundred trollies and apertures each. In this embodiment there is a lead trolley, or first trolley  22 , a plurality of intermediate trollies  26 ,  30 ,  34 ,  38 ,  42 ,  46 ,  50 ,  54 , and a rear trolley or tenth trolley  58 . As such, additional configurations of rails and apertures may be provided, including where all are on one side with differing arm shapes, and staggered in any manner to allow the back trollies to pass the front trollies in a first direction and allowing the front trollies to lock back in place through the magnetic portions on the trollies and apertures on the rail stops. Any other type of latching or locking engagement may be utilized instead of the magnetic portions and apertures on the rail stops described herein. 
     Further, while the embodiment provides for five lances further embodiments may provide for as few as one and as many as fifty. Additional embodiments would operate in substantially the same way, would just require fewer or additional apertures within the trollies to adequately support the lances as well as additional swivels operative to rotate the lances. 
     Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments. 
     While various inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure. 
     All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms. 
     The articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” The phrase “and/or,” as used herein in the specification and in the claims (if at all), should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc. As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law. 
     As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc. 
     When a feature or element is herein referred to as being “on” another feature or element, it can be directly on the other feature or element or intervening features and/or elements may also be present. In contrast, when a feature or element is referred to as being “directly on” another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being “connected”, “attached” or “coupled” to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being “directly connected”, “directly attached” or “directly coupled” to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that overlap or underlie the adjacent feature. 
     Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper”, “above”, “behind”, “in front of”, and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms “upwardly”, “downwardly”, “vertical”, “horizontal”, “lateral”, “transverse”, “longitudinal”, and the like are used herein for the purpose of explanation only unless specifically indicated otherwise. 
     Although the terms “first” and “second” may be used herein to describe various features/elements, these features/elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed herein could be termed a second feature/element, and similarly, a second feature/element discussed herein could be termed a first feature/element without departing from the teachings of the present invention. 
     An embodiment is an implementation or example of the present disclosure. Reference in the specification to “an embodiment,” “one embodiment,” “some embodiments,” “one particular embodiment,” or “other embodiments,” or the like, means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments, of the invention. The various appearances “an embodiment,” “one embodiment,” “some embodiments,” “one particular embodiment,” or “other embodiments,” or the like, are not necessarily all referring to the same embodiments. 
     If this specification states a component, feature, structure, or characteristic “may”, “might”, or “could” be included, that particular component, feature, structure, or characteristic is not required to be included. If the specification or claim refers to “a” or “an” element, that does not mean there is only one of the element. If the specification or claims refer to “an additional” element, that does not preclude there being more than one of the additional element. 
     As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word “about” or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and/or position to indicate that the value and/or position described is within a reasonable expected range of values and/or positions. For example, a numeric value may have a value that is +/−0.1% of the stated value (or range of values), +/−1% of the stated value (or range of values), +/−2% of the stated value (or range of values), +/−5% of the stated value (or range of values), +/−10% of the stated value (or range of values), etc. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. 
     Additionally, any method of performing the present disclosure may occur in a sequence different than those described herein. Accordingly, no sequence of the method should be read as a limitation unless explicitly stated. It is recognizable that performing some of the steps of the method in a different order could achieve a similar result. 
     In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
     Moreover, the description and illustration of various embodiments of the disclosure are examples and the disclosure is not limited to the exact details shown or described.