Patent Publication Number: US-8540069-B2

Title: Kinematically-driven slow delivery lubrication system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a 35 U.S.C. §371 U.S. national stage filing of International Patent Application No. PCT/US09/68813, filed on Dec. 18, 2009. 
     BACKGROUND 
     1. Technical Field 
     Systems and methods are disclosed for lubricating a transport system, in particular an escalator or a moving walk. The disclosed systems are driven kinematically by a rotating shaft of the transport system and converting the relatively fast rotational motion of the shaft to a slow linear motion for delivering lubricant over prolonged dispense cycles. As a result, the disclosed systems and methods use substantially less lubricant than conventional systems. 
     2. Description of the Related Art 
     An escalator includes a plurality of steps that are connected together by one or more circulating step chains forming an endless loop. The escalator steps are arranged to be able to be vertically offset relative to each other along certain portions of the endless loop to create a vertical rise. In contrast, a moving walk includes a plurality of pallets that are joined together by one or more circulating pallet chains for the horizontal transportation. In both transport systems, handrails can be provided that are driven via handrail chains. Step chains, pallet chains and handrail chains are typically coupled to one or more drive units by sheaves or sprockets driven by an electric motor. 
     To reduce friction and power requirements and to increase the service life of the transport system, the step, pallet and handrail chains should be lubricated at regular intervals. Additionally, escalator and moving walk systems also include parts that require regular lubrication such as bearings, other chains, ropes, etc. Preferably, the lubrication is performed automatically. 
     Currently available automatic lubrication systems include: “drip-feed” systems or gravity fed systems that supply lubricant intermittently in the form of droplets applied directly to parts needing lubrication; “oil-mist” or injection spray systems that spray or inject lubricant on parts needing lubrication; and continuous feed systems that deliver lubricant in the form of a stream to parts needing lubrication. Each of these lubricating systems have inherent disadvantages. 
     One common disadvantage is inefficient use of lubricant or wasted lubricant. Because most lubricants are derived from non-renewable petroleum sources, wasted lubricant is becoming a greater concern as companies are being encouraged to reduce their use of fossil fuels, reduce their carbon footprint and conduct themselves in environmentally sensitive ways. Further, wasted lubricant must also be safely disposed of, which may be problematic for the maintenance crew of the transport system or the building owner if a recycling facility is not readily accessible. 
     Returning to the disadvantages of currently available lubricating systems, drip-feed systems suffer from difficulties in terms of timing the droplet discharge from the nozzle with the link points of each chain link joint. The flow of lubricant typically cannot be easily moderated with drip-feed systems, which means that lubrication also takes place when the escalator or moving walk is stationary thereby resulting in waste. Drip-feed systems also cannot respond adequately to environmental conditions that require different quantities of lubricant. Furthermore, different lubrication requirements of different lubrication points cannot normally be accommodated with drip-feed systems. 
     Oil-mist or injection-spray type systems disperse lubricant on areas that do not need lubricant, thereby contaminating the surroundings and wasting lubricant. The continuous oil feed systems discharge lubricant at too high of a rate thereby also contaminating the surroundings and wasting lubricant in a manner similar to “oil-mist” lubrication systems. As a counter-measure to the excessive lubrication, an oil pan can be disposed below the power transmission train. However, oil pans must be drained thereby requiring additional labor and maintenance expenses and oil pans obviously do not solve the lubricant waste problem. While operators can be employed to lubricate transportation chains manually, such procedures are costly and expose the operators to unnecessary dangers. 
     Therefore, a need exists for improved lubricant delivery systems for transport systems such as escalators and moving walks which can more efficiently deliver needed quantities of lubricant than currently available systems. 
     SUMMARY OF THE DISCLOSURE 
     In satisfaction of the aforenoted needs, lubrication systems for transport systems are disclosed that are powered by a rotating shaft of the transport system. The lubrication system comprises at least one circular member mounted on the rotating shaft. The at least one circular member is coupled to and imparts rotation to a third circular member and separately to a fourth circular member for imparting rotation thereto. The third circular member is coupled to a first linkage. The first linkage extends from the third circular member to a fifth circular member. The fourth circular member is coupled to a second linkage. The second linkage couples the fourth circular member to the first linkage between the third and fifth circular members. The fifth circular member is coupled to a pump shaft. As a result, rotation of the third and fourth circular members imparts rotational movement to the fifth circular member and axial movement of the fifth circular member and pump shaft for pumping lubricant. 
     A method for pumping lubricant slowly using a rotating shaft of a transport system is also disclosed. The method comprises: coaxially mounting a first circular member and a second circular member on the rotating shaft for rotation with the rotating shaft; providing coaxial third, fourth and fifth circular members and a pump shaft coaxially coupled to the fifth circular member; coupling the first circular member to a third circular member and the second circular member the fourth circular member for imparting rotation to the third and fourth circular members respectively; coupling the third circular member to a fifth circular member with a first rigid linkage; coupling the fourth circular member to the first rigid linkage with a second rigid linkage at a joint disposed between the third and fifth circular members; rotating the first and second circular members with the rotating shaft thereby rotating the third and fourth circular members thereby rotating the fifth circular member and moving the fifth circular member and pump shaft axially, thereby pumping lubricant with the pump shaft. 
     By varying the difference in combined diameters of the first and third circular members and the second and fourth circular members, the time period for the pump shaft to complete one cycle can be shortened or lengthened. 
     Other advantages and features will be apparent from the following detailed description when read in conjunction with the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the disclosed methods and apparatuses, reference should be made to the embodiments illustrated in greater detail in the accompanying drawings, wherein: 
         FIG. 1  diagrammatically illustrates a disclosed lubrication system in a bottom dead center position; 
         FIG. 2  diagrammatically illustrates the disclosed lubrication system of  FIG. 1  in a top dead center position; 
         FIG. 3  is an overlay of  FIGS. 1 and 2  illustrating the rotational movement of the rigid linkage members and axial movement of the pump shaft; 
         FIGS. 4-5  graphically illustrate the X-Y plane in the linkage plane as defined by (1) the linkage coupling the third circular member to the fifth circular member, (2) the linkage coupling the fourth circular member to the third and fifth circular members and (3) the fifth circular member, and for explaining the mathematical derivations described below that are based on the spatial relationships illustrated in  FIGS. 1-3 ; 
         FIG. 6  graphically illustrates the axial position of the fifth circular member as a function of the rotational position of the fifth circular member during one complete stroke cycle; 
         FIG. 7  is a partial perspective view illustrating an exemplary joint used to couple the linkages to the rotating circular members; 
         FIGS. 8-10  illustrate the incorporation of three disclosed lubrication systems in a transport drive system; and 
         FIGS. 11-12  diagrammatically illustrate two additional disclosed lubrication systems in their respective bottom dead center positions. 
     
    
    
     It should be understood that the drawings are not necessarily to scale and that the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In certain instances, details which are not necessary for an understanding of the disclosed methods and apparatuses or which render other details difficult to perceive may have been omitted. It should be understood, of course, that this disclosure is not limited to the particular embodiments illustrated herein. 
     DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
     Turning to  FIG. 1 , a lubrication system  10  is illustrated with one or two circular members  11 ,  12  that may be provided in the form of sheaves, sprockets, wheels, pulleys, etc. In the example illustrated in  FIGS. 1-3 , the circular members  11 ,  12  are coaxially mounted on a rotating shaft shown schematically at  13  in  FIGS. 1-3 . The first and second circular members  11 ,  12  may be mounted on the rotating shaft  13  in a side-by-side fashion or a single cylindrical structure may be utilized for both circular members  11 ,  12 . The rotating shaft  13  is part of a transport system such as an escalator or moving walk. The lubrication system  10  does not need its own power supply or motor; it simply operates using a rotating shaft  13  and does not affect the overall drive performance of the transport system. The diameters or radii of the rotating circular members  11 ,  12  may be identical as indicated in  FIGS. 1-3 , or they may differ from each other. 
     The first and second circular members  11 ,  12  are coupled to second and third circular members  14 ,  15  respectively. In the embodiment illustrated in  FIGS. 1-3 , the first and second circular members  11 ,  12  are coupled to the third and fourth circular members  14 ,  15  by chains, belts, pulleys, toothed belts, gears etc. shown schematically at  16 ,  17  respectively. The means for coupling the first and second circular members  11 ,  12  (or unitary circular member structure  11 ,  12 ) to the third and fourth circular members  14 ,  15  may be varied as will be apparent to those skilled in the art. The third and fourth circular members  14 ,  15  may also be provided in the form of sheaves, sprockets, wheels, pulleys, etc. If the first and second circular members  11 ,  12  are of the same size or diameter as illustrated in  FIGS. 1-3 , the third and fourth circular members  14 ,  15  should have different effective outer diameters or effective radii R 14 , R 15  respectively for reasons explained below. However, it is sufficient to vary their combined diameters of the first and third circular members  11 ,  14  and the second and fourth circular members  12 ,  15  so that the fourth circular member  15  rotates any different angular speed than the third circular member  14 . 
     Still referring to  FIG. 1 , the third circular member  14  is coupled to a first linkage  21  by a joint  22 . The first linkage  21  couples the third circular member  14  to a fifth circular member  23  at a joint  24 . The fourth circular member  15  is coupled to the first linkage  21  by a second linkage  25 . The second linkage  25  is coupled to the fourth circular member  15  by the joint  26  and to the first linkage member  21  by the joint  27 . The joints  22 ,  24 ,  26 ,  27  may be provided in a variety of forms and most pivotal connection-type joints will suffice. An example of a suitable mechanism for the joint  24  is illustrated in  FIG. 7 . The joint  27  may be a simple hinge mechanism as shown in  FIGS. 1-3 . 
     In the system  10  illustrated in  FIG. 1 , the joint  22  is coupled to the third circular member  14  at its outer periphery. In contrast, the fourth circular member  15  includes a pair of cross-frame members  31 ,  32  that support an inner ring or hoop  33 . The joint  26  is coupled to the inner ring  33 . As a result, in the system illustrated in  FIGS. 1-3 , the joint  26  is disposed radially inwardly from the outer periphery of the rotating fourth circular member  15 . 
     The fifth circular member  23  is coupled to a pump shaft  34  that may be in the form of a bearing housing or cylinder as shown in  FIGS. 1-3  or a piston  35 . In the system  10  illustrated in  FIGS. 1-3 , the outer pump shaft  34  moves axially with the fifth circular member  23  while the piston  35  remains stationary. Another option would be to have the piston  35  move with the fifth circular member  23  and the outer shaft  34  remaining stationary. The piston  35 , pump shaft  34 , a fifth circular member  23 , fourth circular member  15  and third circular member  14  are coaxial along a common axis shown at  36 . The first and second circular members  11 ,  12  are coaxial about the common axis shown at  37 . 
     Referring to the common axis  36 , the joint  26  is spaced apart from the axis  36  by the radius (r). The joint  22  is spaced apart from the common axis  36  by the radius R 14 . 
     In the position shown in  FIG. 1 , the piston  35  is in a “bottom dead center” position with respect to the pump shaft  34  and linkages  21 ,  25  in their uppermost center positions with respect to the common axis  36 . Comparing  FIGS. 1 and 2 , the fifth circular member  23  and pump shaft  34  are in a fully retracted position in  FIG. 1  and in a fully extended position in  FIG. 2 . In  FIG. 2 , the piston  35  is in a “top dead center” position with respect to the pump shaft  34  and the joint  22  disposed below the common axis  36 . The transition from the bottom dead center position of  FIG. 1  to the top dead center position of  FIG. 2  represents one complete stroke of the pump shaft  34 .  FIG. 3  is an overlay of the position shown in  FIGS. 1 and 2  indicating the stroke distance (s). 
     In addition to the radial distance R between the joint  22  and common axis  36  and the radial distance (r) between the joint  26  and the common axis  36 , other relevant dimensions illustrated in  FIGS. 1-3  include is the variable distance d(t) between the two joints  22 ,  26 , the length (a) between the joints  22 ,  27 , the length (b) between the joints  26  and  27  (or the length of the second linkage  25 ) and the length (c) between the joints  27 ,  24 . The overall length of the first linkage  21  is the sum of (a) and (c). 
     The first and second circular members  11 ,  12  are coaxial as noted above and rotate with the same relatively high angular speed, but do not necessarily have the same diameter. The third and fourth circular members  14 ,  15 , rotate at slightly different angular speeds due to their different radii R 14 , R 15  respectively. If the first and second circular members  11 ,  12  have different sizes, then the third and fourth circular members  14 ,  15  can be of the same size. The third and fourth circular members  14 ,  15  are also not necessarily coaxial. Each of the circular members  14 ,  15  is coupled to one of the linkages  21 ,  25  respectively. The plane in which the linkages  21 ,  25  are disposed can be either parallel to the plane of the circular members  14 ,  15  or inclined with respect to the plane of the circular members  14 ,  15 . In  FIGS. 4-5 , the plane in which the first and second linkages  21 ,  25  are disposed is perpendicular to the planes of the third and fourth circular members  14 ,  15 . The linkage joint distances (a), (b), (c) are equal in the example illustrated in  FIGS. 1-3  but may be different from one another. Rotation of the linkages  21 ,  25  provide a rotational and linear axial movement of the output joint  24 , which disposed on the fifth circular member  23 . As a result, the first and second linkages  21 ,  25  and the output joint  24  rotate circularly and move axially the stroke distance (s) in response to rotation of the third and fourth circular members  14 ,  15  as illustrated in  FIGS. 1-3 . 
     Due to the spacing of the linkage joints  22 ,  26 ,  27 , the output joint  24  moves circular with the same diameter of the ring  33  and reiteratively and parallel to the common axis  36 . The output joint  24  is connected to the fifth circular member  23  which follows the circular and axial movement of the output joint  24 . The bush bearing housing or pump shaft  34  is mounted on the axis  36  and moves axially with the fifth circular member  23 . A piston  35  can be mounted in the shaft  34  or vice versa. The iteration period or stroke period time is dependent on the absolute value of the angular velocity difference |ω14−ω15| between member  14  and member  15  due to the fact that the angular velocities ω14=ω22 and ω15=ω26 are always the same the absolute angular velocity difference can be also expressed by |ω22−ω26|. This difference is dependant on ratio i 11 =R 11 /R 14  (the ratio between first member  11  and third member  14 ) and ratio i 12 =R 12 /R 15  (the ratio between second member  12  and fourth member  15 ) and the according input angular velocities ω 11  of member  11  and ω 12  of member  12 . The smaller the absolute value of the angular velocity difference |ω22−ω26| the longer the stroke period t. t is infinite when the difference |ω22−ω26| is zero. The ratio R/r (or better the difference R−r) has an influence on the stroke distance s in conjunction with the linkage dimensions a, b, c but, in the disclosed example, only a as seen in equation 3.14. Ratios of the radii R 11 , R 12  of the small circular members  11 ,  12  and the radii R 14 , R 15  of the larger circular members  14 ,  15  can vary greatly as will be apparent to those skilled in the art. 
     Referring to  FIG. 4 , a coordinate system is shown for the XY plane in which the linkage members  21 ,  25  are disposed as indicated by the joints  22 ,  26 . The angle φ represents the relative deviation angle between the joint  26  and the common axis  36  which results due to the different angular velocities ω 22 , ω 26  of the joints  22 ,  26  disposed on third and fourth circular members  14 ,  15  respectively:
 
φ( t )=|0 t∫ω   22 −ω 26   dt|   (0.1)
 
     The variable distance d (t) between the joints  22 ,  26  can be represented by
 
 d ( t )= r (sin(φ( t ))/sin(δ( t )))  (0.2)
 
     The following kinematical equations and assumptions from the geometry in the top view plane ( FIG. 4 ) may be used:
 
 d =(( R+r  cos(φ)) 2 +( r  sin(φ)) 2 )½  (1.1)
 
 d =( R   2 +2 Rr  cos(φ) +r   2 )½  (1.1.1)
 
     The following general kinematical equations and assumptions from the geometry in the XY plane ( FIG. 5 ) may also be used:
 
 a  sin(α)= b  sin(β)  (2.1)
 
cos(β)=(1−( a/b  sin(α)) 2 )½  (2.1.1)
 
 d=a  cos(α) +b  cos(β)  (2.2)
 
 d−a  cos(α)= b  (1−( a/b  sin(α)) 2 )½  (2.2.1)
 
 d   2 −2 ad  cos(α) +a   2 (cos(α)) 2   =b   2   −a   2 (sin(α)) 2   =b   2   −a   2   +a   2 (cos(α)) 2   (2.2.2)
 
 d   2 +[−2 a  cos(α) ]d+[a   2   −b   2 ]=0  (2.2.3)
 
 p=[− 2 a  cos(α)]  (2.2.3.1)
 
 q=[a   2   −b   2 ]  (2.2.3.2)
 
 d   1,2   =−p/ 2±(( p/ 2) 2   −q )½  (2.2.3.3)
 
     The distance d is dependent of a ( FIG. 5 ) and can be expressed as:
 
 d=a  cos(α)±( a   2 (cos(α)) 2   +b   2   −a   2 )½  (2.2.3.4)
 
     The velocity of the fifth circular member  23  may be calculated as follows. Assuming that a=b, Equation 2.2.14 can be rewritten as:
 
 d=a  cos(α) ±a  cos(α)  (3.2)
 
With the only non trivial solution being d=2a cos(α). Rewriting equation 1.1.1 for d in dependency of φ provides the following expression:
 
 d= 2 a  cos(α)=( R   2 +2 Rr  cos(φ) +r   2 )½  (3.4)
 
cos(α)=( R   2 +2 Rr  cos(φ) +r   2 )½/2 a   (3.4.1)
 
     The Y-position of the fifth circular member  23  can then be expressed as:
 
 y (α)(24)=( a+c )sin(α)  (3.5)
 
 y (α)(24)=( a+c )(1−(cos(α)) 2 )½  (3.5.1)
 
     The X-position of the fifth circular member can then be expressed as:
 
 x (α)(24)=( a+c )cos(α)  (3.6)
 
 x (α)(24)=( a+c )( R   2 +2 Rr  cos(φ) +r   2 )½/2 a   (3.6.1)
 
     Assuming c=a, the Y-position of the fifth circular member  23  can be written as:
 
 y (φ)(24)=(4 a   2   −R   2 −2 Rr  cos(φ) −r   2 )½  (3.8)
 
     Equation (3.8) can be differentiated for the following Y-velocity equation:
 
 y ′(φ)(24)= R  sin(φ)(4 a   2   −R   2 −2 Rr  cos(φ) −r   2 )−½  (3.9)
 
     The maximum/minimum Y-position of the fifth circular member  23  can be found by
 
 y ′(φ)(24)=0 =R  sin(φ)  (3.10)
 
with two solutions for φ 1,2 =0; π. The top Y-position can be expressed as follows:
 
φ top =π
 
 y (φ)(24)top=(4 a   2   −R   2 +2 Rr−r   2 )½=(4 a   2 −( R−r ) 2 )½  (3.12)
 
     For the bottom Y-position, φ bottom =0 and,
 
 y (φ)(24) bottom =(4 a   2   −R   2 +2 Rr−r   2 )½=(4 a   2 −( R+r ) 2 )½  (3.13)
 
     With equation (3.12) and (3.13) the stroke distance s ( FIG. 3 ) can be expressed as
 
 s =(4 a   2 −( R−r ) 2 )½−(4 a   2 −( R+r ) 2 )½  (3.14)
 
     Equation (3.12) provides the geometrical boundary condition for the minimum dimension for linkage distance a:
 
 a ≧( R+r )/2  (3.15)
 
     The calculation of the stroke period is as follows. Using equation (0.1)
 
φ( t )=|0 t∫ω   22 −ω 26   dt|   (0.1)
 
     For one stroke (φ=2π), a certain time period is required. With
 
ω 22 ,ω 26 =const( dω/dt= 0)  (4.1)
 
     Equation (0.1) can be rewritten as
 
2π= t|ω   22 −ω 26 |  (4.2)
 
     The angular velocity where R 14  (Equations 03, 09) is the radius of the driven circular member  14  (and the joint  22  is disposed on the outer periphery of the member  14  with the radius R. R 15  is the radius of the driven circular member  15  and the joint  26  is disposed with the radius r. v 22 , v 26  the corresponding circumferential velocities of the joints  22 ,  26  can be expressed as:
 
ω 22   =v   22   /R   (4.3)
 
ω 26   =v   26   /r   (4.4)
 
     Using v 0  as the circumferential velocity of the first and second circular members  11 ,  12  and ω 0  the corresponding angular velocity of the first and second circular members  11 ,  12 , and R 0  as the radius of the first and second circular members  11 ,  12 . The angular velocities of the joints  22 ,  26  disposed on the third and fourth circular members  14 ,  15  can be expressed as:
 
ω 22 =ω 0   R   0   /R   14   (4.6)
 
ω 26 =ω 0   R   0   /R   15   (4.7)
 
     With corresponding ratios expressed as:
 
 R   0   /R   14   =i   22   (4.8)
 
 R   0   /R   15   =i   26   (4.9)
 
     ω 22 , ω 26  can be rewritten as:
 
ω 22 ω 0   i   22   (4.10)
 
ω 26 =ω 0   i   26   (4.11)
 
     Equation (4.2) can then be rewritten as:
 
ω 0 ( i   26   −i   22 ) t= 2π  (4.12)
 
with
 
ω 0   =n   0 π/30 [ n   0  is in Rpm]  (4.13)
 
Δ i =( i   22   −i   26 )  (4.14)
 
     The stroke period can be expressed as
 
 t= 60 /n   0   Δi [t  in second]  (4.15)
 
     The radius dimensions dependent on the required stroke period (t) can be expressed as:
 
 R   0   /R   14   −R   0   /R   15   =Δi= 60/( n   0   t )  (5.1)
 
 R   0 (( R   14   −R   15 )/ R   14   R   15 )=Δ i   (5.2)
 
 R   14   −R   15   =ΔR   (5.3)
 
Δ R=ΔiR   14   R   15   /R   0   =R   14   Δi/i   26   =R   14 60/( i   26   n   0   t )  (5.4)
 
     With R 15 =R 14 −ΔR, a relation between the radii and the stroke period can be expressed as:
 
 R   15   =R   14 (1−60/( i   26   n   0   t ))  (5.6)
 
     An example is illustrated graphically in  FIG. 6  wherein: R=50.0 mm; r=R 26 =R 23 =17.5 mm; a=40.0 mm; n 0 =60.0 rpm; ω 0 =60*π/30=2π; R 0 =10.0 mm (=R 11 =R 12 ); R 14 =51.25 mm; and R 15 =46.0 mm. In  FIG. 6 , the Y-position of the joint  24  is indicated by the curve  41  and Y-velocity over φ° of the output joint  24  is indicated by the curve  42  for one complete stroke cycle. The following results are produced: stroke distance s=30.16 mm; ratios: i 22 =R 0 /R 14 =10/51.25=0.19607 [23], i 26 =R 0 /R 15 =10/46=0.21739; Δi=i 26 −i 22 =0.02131; rotation velocities ω 22 =1.232 (n 22 =11.76), ω 26 =1.366 (n 26 =13.04); stroke period)(360°) t=60/n0Δi=60/(60*0.02131)=46.92 sec. 
       FIG. 7  illustrates one example of a mechanism that may be used for the joint  24  as well as the joints  22  and  26 . The joints  24 ,  22 ,  26  must be able to rotate about two axes. In  FIG. 7 , the joint  24  rotates about the axis  44  as indicated by the arrow  45  and about the axis  46  as indicated by the arrow  47 . Other types of pivoting joints will be apparent to those skilled in the art. 
       FIGS. 8-10  illustrate the incorporation of a disclosed lubrication system  10  in a transport system, in this case, a moving walk  100 . One lubrication system  10  can be used to drive several pumps  50  although only three pumps  50  are illustrated in  FIG. 10 . 
     Finally,  FIGS. 11-12  illustrate systems  10   a  and  10   b  respectively. In the system  10   a , in contrast to the system  10  illustrated in  FIGS. 1-3  above, the joint  22  is disposed radially inwardly from the outer periphery of the driven circular member  14 . An inner ring  33   a  is mounted to the circular member  14  on crossbars  31   a ,  32   a . Joint  26  is disposed at the outer periphery of the driven circular member  15 . In  FIG. 12 , two inner rings  33 ,  33   a  are used on both circular members  15 ,  14  respectively to move the joints  26 ,  22  radially inwardly from the outer peripheries of the circular members  15 ,  14  respectively. 
     While only certain embodiments have been set forth, alternatives and modifications will be apparent from the above description to those skilled in the art. These and other alternatives are considered equivalents and within the spirit and scope of this disclosure and the appended claims.