Patent Publication Number: US-2020290703-A1

Title: Motorcycle front brake master cylinder assembly

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. 
     BACKGROUND 
     Field 
     The present disclosure relates to generally to hydraulic brake systems and, in particular, to a handbrake system for a motorcycle, dirt bike, or ATV. 
     Description of Related Art 
     Hydraulic brake systems often use an incompressible fluid to generate leverage for squeezing a brake pad against a rotor. In a hydraulic handbrake system, when the brake lever is squeezed, a pushrod exerts force on a piston in the master cylinder. Movement of the piston in the master cylinder seals off the bypass or compensation port, trapping fluid ahead of the piston. Further movement of the piston increases the pressure of the entire hydraulic system, forcing fluid through the hydraulic lines toward one or more calipers where the fluid acts upon one or two caliper pistons sealed by one or more seated O-rings that prevent leakage of the fluid. 
     Subsequent release of the brake lever allows a return mechanism (e.g., a spring in the master cylinder assembly) to return the master piston back into its rest position. This return action first relieves the hydraulic pressure on the caliper, then applies suction to the brake piston in the caliper assembly, moving it back into its housing and allowing the brake pads to release the rotor. 
     SUMMARY 
     The systems, methods and devices described herein have innovative aspects, no single one of which is indispensable or solely responsible for their desirable attributes. Without limiting the scope of the claims, some of the advantageous features will now be summarized. 
     An aspect of the present invention is a lever configured to compress a pushrod of a master cylinder assembly of a brake assembly, the lever having a removable insert that allows the leverage between the lever and the pushrod to be changed. In some aspects, the orientation of the removable insert within the lever can be changed to change the leverage between the lever and the pushrod. The brake assembly may include more than one inserts, with some, all, or none of the inserts providing a different leverage between the lever and the pushrod. In some aspects, the lever includes a knee portion, a handle portion, and a set screw that allows the position of the handle relative to the knee to be adjusted. In some aspects, the master cylinder assembly is coupled to a perch that secures the brake assembly to a handlebar of a motorcycle or ATV. In some aspects, the perch is positioned to overlap longitudinally with a pivot that connects the lever to the master cylinder assembly. In certain aspects, the master cylinder assembly includes protrusions on the outer surface of the cylinder to protect the cylinder from damage without increasing the entire wall thickness of the cylinder. In some aspects, the master cylinder assembly includes a guard that has a flange having a low clearance with a portion of the lever, with the flange operating as a wiper to remove debris from the lever as the lever is operated. In some aspects, a collar is inserted between the perch and the handlebar to allow the brake assembly to rotate about the handlebar during impact, thereby protecting the brake assembly from damage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Throughout the drawings, reference numbers can be reused to indicate general correspondence between reference elements. The drawings are provided to illustrate example embodiments described herein and are not intended to limit the scope of the disclosure. 
         FIG. 1  is a top view of an embodiment of a hydraulic brake assembly. 
         FIG. 2  is a rear cross-sectional view of the master cylinder assembly portion of the brake assembly of  FIG. 1 . 
         FIG. 3  is a upwardly-angled front view of the master cylinder assembly of  FIG. 2 . 
         FIG. 4  is an isometric view of the guard and master cylinder assembly of  FIG. 2 . 
         FIG. 5A  is an isometric view of the knee and lever portion of the brake assembly of  FIG. 1 . 
         FIG. 5B  is an assembly view of the knee and lever portion of  FIG. 5A . 
         FIG. 6  is an end view of the guard and master cylinder assembly of  FIG. 4 . 
         FIGS. 7A  and B show front and side views of inserts having different cavity configurations. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of systems, components and methods of assembly and manufacture will now be described with reference to the accompanying figures, wherein like numerals refer to like or similar elements throughout. Although several embodiments, examples and illustrations are disclosed below, it will be understood by those of ordinary skill in the art that the inventions described herein extends beyond the specifically disclosed embodiments, examples and illustrations, and can include other uses of the inventions and obvious modifications and equivalents thereof. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner simply because it is being used in conjunction with a detailed description of certain specific embodiments of the inventions. In addition, embodiments of the inventions can comprise several novel features and no single feature is solely responsible for its desirable attributes or is essential to practicing the inventions herein described. 
     Certain terminology may be used in the following description for the purpose of reference only, and thus are not intended to be limiting. For example, terms such as “above” and “below” refer to directions in the drawings to which reference is made. Terms such as “front,” “back,” “left,” “right,” “rear,” and “side” describe the orientation and/or location of portions of the components or elements within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the components or elements under discussion. Moreover, terms such as “first,” “second,” “third,” and so on may be used to describe separate components. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. 
     Overview 
       FIG. 1  depicts a top view of a non-limiting, illustrative embodiment of a brake assembly  100 . The brake assembly  100  can include a lever  200 , a knee  300 , a master cylinder assembly  400 , and a guard  500 . The lever  200  can be coupled to the knee  300  by a pin  110 . In some variants, the brake assembly may not include a pin  110 , with the lever  200  and the knee  300  being portions of a continuous, unitary structure. The pin  110  can be many different types of a fastener (e.g., a bolt, a weld). The lever  200  can be adapted to rotate about the pin  110 . In some embodiments, the lever  200  can be restricted from rotating about the pin  110 . 
     The knee  300  can be coupled to the master cylinder assembly  400  by a pivot  120 . The pivot  120  can be many different types of a fastener (e.g., a bolt, a screw, a pin). The knee  300  can be adapted to rotate about the pivot  120 . 
     The guard  500  can be secured to the master cylinder assembly  400  by a fastener  130 . The fastener  130  can be many different types of a fastener (e.g., a bolt, a weld). In some variants, the guard  500  can be formed as a continuous, unitary structure of another component of the brake assembly  100  (e.g., the master cylinder assembly  400 , the knee  300 , the lever  200 ). 
     The master cylinder assembly  400  may include or be coupled to a perch  410  that is adapted to secure the brake assembly  100  to a secondary structure (e.g., handlebar). The brake assembly  100  can be configured so that a brake is applied when the lever  200  is moved in a first direction (e.g., toward the handlebar). The brake assembly  100  can be configured so that the brake is released when the lever  200  is moved in a second direction (e.g., away from the handlebar). The brake assembly  100  can be arranged so that the brake is applied when the lever  200  rotates in a first direction about the pivot  120 , and the brake is released when the lever  200  rotates in a second direction about the pivot  120 , with the first and second directions being opposite directions of rotation around the pivot  120 . 
     The brake assembly  100  can be arranged so that the lever  200  pushes the knee  300  toward the master cylinder assembly  400  when the lever  200  moves toward the perch  410 . As shown in  FIG. 1 , the brake assembly  100  can include an adjustment element  140 . The adjustment element  140  can be adapted to allow adjustment of the rest position of the lever  200  relative to the knee  300 . The adjustment element  140  can be coupled to the lever  200  by a coupling element  202  of the lever  200 . The adjustment element  140  can engage a fin  310  on the knee  300 . In some variants, the orientation of the adjustment element  140  can be flipped so that the adjustment element  140  couples to the knee  300  and engages a “fin-like” structure (not shown) on the lever  200 . 
     Referring to  FIG. 1 , the adjustment element  140  can serve as an intervening structure through which the lever  200  can move the knee  300  toward the master cylinder assembly  400 . In some embodiments, the lever  200  can move the knee  300  toward the master cylinder assembly  400  through a non-adjustable portion of the lever  200 . 
     Master Cylinder Assembly 
       FIG. 2  depicts a rear cross-sectional view of a non-limiting, illustrative embodiment of the master cylinder assembly  400 . The master cylinder assembly  400  can include a reservoir  420 , a cylinder  430 , and a piston  440 . The reservoir  420  can be adapted to contain a liquid  421  (e.g., brake fluid). The cylinder  430  can surround a channel  432  that has a longitudinal axis  434 . The channel  432  can be substantially cylindrical and surround the piston  440 . The channel  432  can be adapted to have a small clearance between the cylinder  430  and the piston  440 . The master cylinder assembly  400  can include an inlet port  422  through which the reservoir  420  can communicate with the channel  432 . The master cylinder assembly  400  can include a compensating port  424  through which the reservoir  420  can communicate with the channel  432 . The master cylinder assembly  400  can include an outlet port  426  through which the channel  432  can communicate with a hydraulic brake line (not shown). 
     The master cylinder assembly  400  can be arranged so that the piston  440  moves within the channel  432  along the longitudinal axis  434 . The piston  440  can include, or be coupled with, a pushrod  442 . The piston  440  can be coupled to the pushrod  442  by a flexible joint (not shown) that allows the pushrod  442  to articulate in one or more directions relative to the piston  440 . The master cylinder assembly  400  can include a sealing element  446  that surrounds the pushrod  442 . The sealing element  446  can be adapted to block the liquid  421  from flowing past the pushrod  442 , as shown in  FIG. 2 . 
     The master cylinder assembly  400  can include a return spring  444 . The return spring  444  can be arranged to be co-axial with the channel  432 . The return spring  444  can be disposed between the piston  440  and the cylinder  430 . As shown in  FIG. 2 , the return spring  444  can be disposed between a distal end surface  436  of the channel  432  and an end  441  of the piston  440 . The return spring  444  can be configured to compress when a compression force is applied to the pushrod  442 , thereby allowing the piston  440  to move toward the distal end surface  436  of the channel  432 . The return spring  444  can be configured to supply a restoring force such that the piston  440  moves away from the distal end surface  436  of the channel  432  when the compression force applied to the pushrod  442  is reduced. The master cylinder assembly  400  can be configured such that movement of the piston  440  toward the distal end surface  436  of the channel  432  increases the pressure of the liquid  421  in the outlet port  426  and in the downstream hydraulic brake line (not shown). The master cylinder assembly  400  can be configured such that movement of the piston  440  away from the distal end surface  436  of the channel  432  decreases the pressure of the liquid  421  in the outlet port  426  and in the downstream hydraulic brake line (not shown). The brake assembly can be configured so that an increase in the pressure of the liquid  421  in the outlet port  426  activates the brake. The brake assembly can be configured so that a decrease in the pressure of the liquid  421  in the outlet port  426  releases the brake. As shown in  FIG. 2 , the piston  440  has moved toward the distal end surface  436 , thereby increasing the pressure of the liquid  421  in the outlet port  426  and activating the brake. 
       FIG. 3  shows an upwardly-angled front view of the master cylinder assembly  400 . The master cylinder assembly  400  can be secured to a perch  410 . As shown in  FIG. 3 , the perch  410  can form a unitary structure with the master cylinder assembly  400 . The perch  410  can be aligned with the pivot  120 . In other words, a line that passes through the pivot  120  and is substantially perpendicular to the longitudinal axis  434  of the channel  432  can pass through at least a portion of the perch  410 . As best seen in  FIG. 1 , the perch  410  can have a width  105 , which is defined by an inboard position  101  of a first lateral surface of the perch and an outboard position  103  of a second lateral surface of the perch  410 . The pivot  120  can be located between the first and second lateral surfaces of the perch  410 . The perch  410  can be located inboard of the pivot  120  (e.g., toward the reservoir  420 ). The perch  410  can be located outboard of the pivot  120  (e.g., away from the reservoir  420 ). Positioning the perch  410  to be approximately in line with the pivot  120  allows standard “finger/pocket” positioning on the lever  200 , which allows increased leverage on the lever  200 . As seen in  FIG. 1 , the “finger/pocket” can have a leverage distance  107  with respect to the pivot  120 . Although the “finger/pocket” positioning could also be achieved by sliding outboard an assembly having an inboard perch placement, the handlebar has a limited space available for mounting the brake assembly  100 . For example, the handlebar is curved and must accommodate other components such as a handgrip, thereby limiting the space available for sliding the brake assembly  100  along the handlebar. 
     As shown in  FIG. 3 , the outer surface of the cylinder  430  may include one or more protrusions  452 . The protrusion  452  can be in the form of a raised ridge that runs substantially parallel to a longitudinal axis  434  of the cylinder  430 . However, the protrusion  452  need not be parallel to the longitudinal axis  434 . The protrusion  452  may have a form other than linear (e.g., sinusoidal, zig-zag, punctate). In some variants, the protrusion  452  can be adapted to protect the cylinder  430  from becoming damaged due to impact of the cylinder  430  with an outside structure, such as, for example, flying debris (e.g., a rock). As discussed above, the clearance between the piston and the cylinder  430  can be small, making it likely that any deformation of the cylinder  430  can interfere with the piston moving back and forth within the cylinder  430 . The protrusion  452  can be adapted to shield the outer surface of the cylinder  430  from coming into contact with an outside structure, thereby protecting the cylinder  430  from a deformation that could render inoperable the master cylinder assembly  400 . The protrusion  452  can be adapted to help prevent rock damage to the cylinder  430  without increasing the entire wall thickness of the cylinder  430 , thereby requiring a bigger rock to damage and render inoperable the cylinder  430 . 
       FIG. 4  shows an isometric view of a non-limiting, illustrative embodiment of the master cylinder assembly  400 . The perch  410  can surround an opening  412  through which a secondary structure can be passed. In some variants, the opening  412  can be adapted to allow a handle bar to be passed through the opening  412 . The perch  410  can include a base portion  414  that partially circumferentially surrounds the opening  412 . The perch  410  can include a cap portion  416  that partially circumferentially surrounds the opening  412 . The perch  410  can include one or more clamp elements  418  that are configured to couple the cap portion  416  to the base portion  414 . The clamp element  418  can be many different types of a fastener (e.g., a threaded screw). The perch  410  can be configured to allow the cap portion  416  to be completely removed from the base portion  414 . The perch  410  can be adapted so that the cap portion  416  remains coupled to the base portion  410  when the clamp element  418  is at its fully opened configuration. 
     The perch  410  can include one, none, or more than one liners  411   a,b . The liners  411   a,b  can be disposed immediately adjacent to the opening  412 . The perch  410  can include a cap liner  411   a  and/or a base liner  411   b . The liners  411   a,b  can be fused to the perch  410 . In some variants, the liners  411   a,b  can be removable inserts. In at least one embodiment, the cap liner  411   a  can be a continuous, unitary structure with the base liner  411   b . For example, the cap liner  411   a  and the base liner  411   b  can be in the form of a single liner that completely surrounds the opening  412 , such as, for example, an annular sleeve. In some variants, the cap liner  411   a  and the base liner  411   b  can be in the form of a single liner that completely or only partially surrounds the opening  412 , such as, for example, a slotted ring. 
     The liners  411   a,b  can comprise a material (e.g., polytetrafluoroethylene, nylon) that reduces the friction between the perch  410  and the secondary structure that is passed through the opening  412 . The liners  411   a,b  can be adapted so that there is more consistent control of adjusted slippage of the brake assembly  100 , allowing the tightness to be adjusted so that the brake assembly  100  will still rotate when impacted. The liners  411   a,b  can be adapted to allow the brake assembly  100  to rotate around the handlebar when impacted, thereby helping to protect the brake assembly  100  from damage resulting from an impact. 
     In some variants, the perch  410  is mounted to a secondary structure (e.g., handlebar) by loosening the clamp element  418  to increase an outer dimension of the opening  412 , passing the secondary structure through the opening  412 , and tightening the clamp element  418  to reduce the outer dimension of the opening  412 . The perch  410  can be mounted by removing the cap portion  416  from the perch  410 , seating the base portion  414  on the handlebar, reconnecting the cap portion  416  to the perch  410 , and tightening the clamp element  418  to reduce an outer dimension of the opening  412 , thereby securing the perch  410  to the handlebar. In some variants, the liners  411   a,b  can be a sleeve or broken ring that is positioned on the handlebar before mounting the perch  410  to the handlebar. In some embodiments, the liners  411   a,b  are inserts that are positioned within the perch  410  before, after, or during mounting the perch  410  to the handlebar. 
     As shown in  FIG. 4 , the pushrod  442  and sealing element  446  can extend toward the knee  300  (shown in  FIG. 1 ) of the brake assembly. The pushrod  442  and sealing element  446  can be configured to articulate in any direction (e.g., toward the perch  410 , toward the guard  500 , toward a lateral surface  419  of the master cylinder assembly  400 ). 
     Knee 
       FIG. 5A  depicts an isometric view of the knee  300  and lever  200 . The knee  300  can include an extension  302  adapted to engage at least a portion of the pushrod  442 . The extension  302  can include a piston-facing surface  304 . The piston-facing surface  304  can be configured to compress against the pushrod  442  as the lever  200  is rotated about the pivot  120  toward the extension  302 . 
     The piston-facing surface  304  can be adapted to receive an insert  306 . For example, the piston-facing surface  304  can include a recess  305  (shown in  FIG. 5B ) adapted to receive the insert  306 . The insert  306  can include a cavity  308 . The cavity can have a depth  305  and be located at a radius  307  from the pivot  120 . The cavity  308  can be configured to receive at least a portion of the pushrod  442 . As mentioned above, the pushrod  442  can articulate with respect to the piston  440 , allowing the pushrod  442  to maintain contact with the cavity  308  as the knee  300  swings in an arc about the pivot  120 . 
     Referring to  FIGS. 7A  and B, the brake assembly  100  can include a plurality of inserts  306 , with some, all, or none of the inserts  306  having a different depth  305  and/or distance  309  from an edge of the insert  306 . Changing the distance  309  of the cavity  308  from the edge of the insert  306  will result in a change in the radius  307 . The depth  305  and/or radius  307  of the insert  306  can be selected to produce a desired leverage ratio between the lever  200  and the pushrod  442 . In some variants, the depth  305  and/or radius  307  of the cavity  308  can be modified to accommodate rider preference and/or the course conditions. In some variants, as the distance  309  is increased, the depth  308  of the cavity can decrease to accommodate the change in angle at which the pushrod  442  engages the insert  306 . The pushrod  442  can articulate to allow the pushrod  442  to engage one or more cavities  308  that have a different depth  305  and/or radius  307 . 
     The insert  306  and the piston-facing surface  304  can be configured to allow the insert  306  to be inserted into the extension  302  in a different orientation. For example, the insert  306  can be adapted fit into the extension  302  when the insert  306  is oriented in two orientations that are 180 degrees apart. As illustrated in  FIG. 5A , in some embodiments the insert  306  can be rotated 180 degrees in the plane of the piston-facing surface  304  so that the cavity  308  still faces the pushrod  440  but has a different radius  307  with respect to the pivot  120 . In this way, three inserts can be adapted to make six leverage ratios. The insert  306  can also include a second cavity  308  on the opposing surface of the insert  306 , allowing a user to flip the insert  306  over so that the cavity  308  on the opposing surface now faces the pushrod  442 . The cavity  308  on the opposing surface can have a depth  305  and/or radius  307  that is different from the cavity  308  on the other surface of the insert  306 . 
       FIG. 5B  depicts an assembly view of a non-limiting, illustrative embodiment of the knee  300 , showing how the insert  306  can be configured to fit into a recess  305  of the knee  300 . The knee  300  can include a port  303  that facilitates removal of the insert  306  from the knee  300 . As illustrated in  FIG. 5B , the port  303  can be a hole that allows a pin to be inserted through the port  303  and push the insert  306  out of the recess  305 . 
     The knee  300  can also include a stop  320 . The stop  320  can be configured to contact an abutment  450  (shown in  FIG. 6 ). As discussed below, the brake assembly can be configured to allow the contact point between the top  320  and the abutment  450  to be adjusted. 
     Lever 
     Referring to  FIG. 5A , the lever  200  can be coupled to the adjustment element  140  by the coupling element  202 . The coupling element  202  can include an internal thread that mates with an external thread on the adjustment element  140 . The brake assembly  100  can include a biasing element  124  that can be configured to compress the adjustment element  140  against a fin  310  (shown in  FIG. 1 ). The biasing element  124  can be, for example, a torsion spring that surrounds the pin  110 . The adjustment element  140  can include a head  142  that has one or more grooves  144  that are configured to receive the fin  310 . The head  142  can include two or more grooves  144  that are substantially perpendicular to one another. The head  142  can include two grooves  144  that are not substantially perpendicular to one another. For example, the head  144  can include four grooves that are 45 degrees apart from one another. 
     The adjustment element  140  can be a “no-tool” adjuster. The position of the adjustment element  140  relative to the lever  200  or knee  300  can be adjusted by pushing the lever  200  against the biasing element  124  to free the head  142  from the fin  310 , thereby allowing the head  142  to be set to a different position relative to the lever  200 . As illustrated in  FIG. 5A , the adjustment element  140  can be adjusted to a different position by turning the head  142  of the adjustment element  140  after the head  142  has been freed from the fin  310 , thereby changing the position of the head  142  relative to the coupling element  202 . In some variants, turning the head  142  can cause an external thread on the adjustment element  140  to advance along an internal thread of the coupling element  202 , thereby causing the head  142  to move longitudinally toward or away from the coupling element  202 . The biasing element  124  can be configured to compress the groove  144  against the fin  310 , thereby blocking the adjustment element  140  from moving when the lever  200  is not extended against the biasing element  140 . Further details of the lever are discussed in U.S. Pat. No. 7,921,747, entitled “COLLAPSIBLE CONTROL LEVER,” filed on Jan. 5, 2005, and which is incorporated herein by reference in its entirety. 
     Guard 
       FIG. 6  is a side view of the master cylinder assembly  400  and the guard  500 . The guard  500  can include one or more flanges  502 . As illustrated in  FIG. 1 , the flange  502  can cover at least a portion of the knee  300 . The clearance between the flange  502  and the knee  300  can be small, allowing the flange  502  to act as a wiper for removing mud or other debris from the knee  300 , for example, as the knee  300  rotates about the pivot  120 . The clearance can be between about 0.1 mm and about 5 mm, between about 0.5 mm and about 3 mm, and between about 1 mm and about 2 mm. In some variants, the knee  300  can be exposed from the guard  500  when the brake is applied, resulting in debris accumulating on the knee  300  and/or lever  200 . When the brake is released, the knee  300  moves back under the guard  500  and the flange  502  wipes debris off of the knee  300  and/or lever  200 , thereby keeping the knee  300  and/or lever  200  clear of debris. 
     As discussed above, the brake assembly  100  can include an abutment  450  that engages a stop  320  on the knee  300 . The abutment  450  can be positioned on the master cylinder assembly  400  or on the guard  500 . The abutment  450  can include a cap surface  454  that contacts the stop  320 . The cap surface  454  can be adjustable to allow the brake lever assembly  100  to be tuned to rider preference and/or course conditions. For example, the cap surface  454  can be a threaded screw (e.g., a set screw) that can be advanced longitudinally away from or toward the master cylinder assembly  400 , thereby changing the rotational angle of the knee  300  at which the stop  320  contacts the cap surface  454 . In some variants, the cap surface  454  can be adjusted to accommodate the pushrod  442  having a longer or shorter length and/or to accommodate the cavity  308  having a greater or lesser depth  305 . 
     CONCLUSION 
     It should be emphasized that many variations and modifications may be made to the herein-described embodiments, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. Moreover, any of the steps described herein can be performed simultaneously or in an order different from the steps as ordered herein. Moreover, as should be apparent, the features and attributes of the specific embodiments disclosed herein may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. 
     Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment. 
     Moreover, the following terminology may have been used herein. The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to an item includes reference to one or more items. The term “ones” refers to one, two, or more, and generally applies to the selection of some or all of a quantity. The term “plurality” refers to two or more of an item. The term “about” or “approximately” means that quantities, dimensions, sizes, formulations, parameters, shapes and other characteristics need not be exact, but may be approximated and/or larger or smaller, as desired, reflecting acceptable tolerances, conversion factors, rounding off, measurement error and the like and other factors known to those of skill in the art. The term “substantially” means that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide. 
     Numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also interpreted to include all of the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “about 1 to 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but should also be interpreted to also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3 and 4 and sub-ranges such as “about 1 to about 3,” “about 2 to about 4” and “about 3 to about 5,” “1 to 3,” “2 to 4,” “3 to 5,” etc. This same principle applies to ranges reciting only one numerical value (e.g., “greater than about 1”) and should apply regardless of the breadth of the range or the characteristics being described. A plurality of items may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. Furthermore, where the terms “and” and “or” are used in conjunction with a list of items, they are to be interpreted broadly, in that any one or more of the listed items may be used alone or in combination with other listed items. The term “alternatively” refers to selection of one of two or more alternatives, and is not intended to limit the selection to only those listed alternatives or to only one of the listed alternatives at a time, unless the context clearly indicates otherwise.