Patent Publication Number: US-10787248-B2

Title: Axle saddle

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of and claims priority to and the benefit of U.S. Ser. No. 14/874,098 filed Oct. 2, 2015 and entitled “AXLE SADDLE,” which is hereby incorporated herein in its entirety for all purposes. 
    
    
     BACKGROUND 
     Aircraft axles may have an undercut between the bearing lands, e.g., for weight reduction or other design considerations. Assembly and installation or removal of a wheel assembly onto such an axle may subject the axle and bearing assembly to damage such as dislodging of the bearing assembly. Damage may occur, for example, as the bearing assembly tilts and impacts the axle undercut or bearing lands. This may lead to bearing failures, damaged wheels and/or lost wheels. 
     SUMMARY 
     In accordance with various embodiments, disclosed is an axle saddle system comprising: a saddle configured to substantially cover an undercut. of an axle over a surface area of the undercut; and at least one saddle strap configured to tighten the saddle around the undercut, wherein the axle comprises an outboard bearing land and an inboard bearing land, wherein the undercut is situated between the outboard bearing land and the inboard bearing land, wherein the undercut comprises an undercut perimeter and an undercut axial length, wherein the undercut is radially tapered with respect to at least one of the outboard bearing land and the inboard bearing land, and wherein the saddle is configured to substantially fill the undercut, such that the substantially filled undercut has a profile which is substantially level with the outboard bearing land and the inboard bearing land. In one embodiment, the saddle has a saddle axial length approximately equal to the undercut axial length. In one embodiment, the saddle comprises a strap channel, wherein the saddle strap is configured to nest within the strap channel. In one embodiment, the saddle strap comprises a buckle, and the saddle comprises a buckle cut out adjacent the strap channel, wherein the buckle is configured to nest within the buckle cut out. In one embodiment, the saddle comprises an outer surface, wherein the saddle strap and the buckle are substantially level with the outer surface when nested. In one embodiment, the axle saddle system comprises three saddle straps, and the saddle comprises three strap channels and three buckle cut outs. In one embodiment, the saddle strap is a stainless steel cable tie. In one embodiment, the saddle further comprises a moisture draining system. In one embodiment, the moisture draining system comprises a plurality of drain holes in the saddle. In one embodiment, the saddle comprises at least one of a cylindrical or a conical geometry. In one embodiment, the saddle has a saddle perimeter and an axial split along the saddle axial length, the axial split spanning between approximately 10° to 45° of the saddle perimeter. In one embodiment, the saddle may be deformed to an open position for insertion over the undercut. In one embodiment, the outboard bearing land and the inboard bearing land are each configured to receive a bearing assembly of an aircraft wheel. In one embodiment, the undercut is tapered with respect to both the outboard bearing land and the inboard bearing land. 
     In accordance with various embodiments, disclosed is an axle method comprising: inserting a saddle over an undercut of an axle, and tightening the saddle around the undercut, wherein the axle comprises an outboard bearing land and an inboard bearing land, wherein the undercut is situated between the outboard bearing land and the inboard bearing land and is radially tapered with respect to at least one of the outboard bearing land and the inboard bearing land, and wherein the saddle is configured to substantially fill the undercut over a surface area of the undercut, such that the substantially filled undercut is substantially level with the outboard bearing land and the inboard bearing land, wherein the undercut comprises an undercut perimeter and an undercut axial length forming the surface area of the undercut, and wherein the saddle has a saddle axial length approximately equal to the undercut axial length. In one embodiment, the axle method further comprises tightening the saddle around the undercut with at least one saddle strap. In one embodiment, the axle method further comprises prying the saddle open before inserting. In one embodiment, the saddle strap comprises a buckle and a strap end, the axle saddle method further comprising inserting the strap end through the buckle, pulling the strap end to tighten the saddle strap around the saddle, and breaking off an excess portion of the saddle strap. 
     In accordance with various embodiments, disclosed is an axle saddle system, comprising: a saddle configured to substantially cover an undercut of an axle over a surface area of the undercut, and a saddle strap configured to tighten the saddle around the undercut, wherein the undercut is situated between an outboard bearing land and an inboard bearing land of the axle, wherein the undercut is radially tapered with respect to the outboard bearing land and the inboard bearing land, wherein the undercut comprises an undercut perimeter and an undercut axial length forming the surface area of the undercut, wherein the saddle has a saddle axial length approximately equal to the undercut axial length, and a saddle perimeter configured to span at least 315 degrees of the undercut perimeter, wherein the saddle is configured to substantially fill the undercut, such that the substantially filled undercut has a profile which is substantially level with the outboard bearing land and the inboard bearing land, wherein the saddle comprises a strap channel, and wherein the saddle strap is configured to nest within the strap channel. In one embodiment, the saddle and saddle strap are metallic. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. The present disclosure will become more fully understood from the detailed description and the accompanying drawings wherein: 
         FIG. 1A  is a partial view of an axle, which is a prior art axle for use with the saddle of the present invention; 
         FIG. 1B  shows interference between the inboard bearings of a wheel and an inboard transition wall of the axle of  FIG. 1A ; 
         FIG. 2  is a perspective view of an axle saddle system comprising a saddle and at least one strap, according to various embodiments; 
         FIG. 3  shows the axle saddle system of  FIG. 2  covering the axle of  FIG. 1A ; and 
         FIG. 4  is an axle method, according to various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     All ranges and ratio limits disclosed herein may be combined. It is to be understood that unless specifically stated otherwise, references to “a,” “an,” and/or “the” may include one or more than one and that reference to an item in the singular may also include the item in the plural. 
     The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration and its best mode, and not of limitation. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that logical, chemical and mechanical changes may be made without departing from the spirit and scope of the invention. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Moreover, many of the functions or steps may be outsourced to or performed by one or more third parties. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact. 
     In accordance with various embodiments, disclosed is an axle saddle system  100  for an axle  101  having an undercut between the outboard and inboard bearing lands. The axle saddle system  100  comprises a saddle configured to fill the axle undercut in order to protect the axle  101  from damage by the installation of a wheel onto the axle. 
     According to various embodiments, and as shown in  FIG. 1A , axle  101  may be a wheel axle, and may comprise an outboard bearing land  102 , an inboard bearing land  104 , and an axle shaft  106  between the outboard bearing land  102  and inboard bearing land  104 . According to various embodiments, the outboard bearing land  102 , and the inboard bearing land  104 , are each configured to receive a bearing assembly  200  of a wheel  202  (e.g. an aircraft wheel), as shown in  FIG. 1B . With reference to  FIG. 1B , according to various embodiments, the bearing assembly  200  comprises an outboard bearing  204  configured to rotationally engage with the outboard bearing land  102 , and an inboard bearing  206  configured to rotationally engage with the inboard bearing land  104 . In various embodiments, outboard bearing  204 , and inboard bearing  206 , may comprising, for example, tapered roller bearings. 
     The axle shaft  106  is typically radially tapered with respect to at least one of the outboard bearing land  102  and inboard bearing land  104  to form an undercut axle shaft or axle undercut  107  between the outboard bearing land  102  and inboard bearing land  104 . According to various embodiments, the axle undercut  107  may be tapered with respect to both the outboard bearing land  102 , and inboard bearing land  104 , with an outboard transition wall  103  between the outboard bearing land  102  and axle undercut  107 , and an inboard transition wall  105  between the inboard bearing land  104  and axle undercut  107 , as shown in  FIGS. 1A and 1B . The outboard transition wall  103  spans radially outwards from the axle undercut  107  to the outboard bearing land  102 , and the inboard transition wall  105  spans radially outwards from the axle undercut  107  to the outboard bearing land  102 . The outboard transition wall  103 , and the inboard transition wall  105  may each have various configurations, such as tapered, straight, etc., according to various embodiments. The axle undercut  107  can take on various configurations, such as conical, cylindrical, etc., according to various embodiments. 
     Due to the radial tapering of the axle undercut  107  with respect to the bearing lands, the inner diameter(s) of the outboard bearing  204  and inboard bearing  206  of bearing assembly  200 , are typically both greater than the outer diameter(s) of the axle undercut  107 , according to various embodiments. This may subject the axle  101  and bearing assembly  200  to damage, including dislodging of the bearing assembly  200 , for example, during assembly, and/or removal of the wheel  202  and bearing assembly  200  (e.g. for repair, maintenance, etc.), and may make installation difficult, as the wheel may fail to translate smoothly over the bearing lands  102  and  104 . Damage may occur, for example, as the bearing assembly  200  tilts and impacts against the axle undercut  107 , exerts torque against one of the outboard bearing land  102  and/or inboard bearing land  104 , impacts against one of the outboard transition wall  103  and/or inboard transition wall  105 , etc.  FIG. 1B  shows a possible scenario wherein the inboard bearing  206  compacts against the inboard transition wall  105  of the inboard bearing land  104 . 
     According to various embodiments, axle saddle system  100  is configured to substantially fill the axle undercut  107 , to create an axle profile  107   a,  which is substantially flush or level with the outboard bearing land  102  and inboard bearing land  104 . According to various embodiments, the outer diameter  108  of the filled axle shaft  106  may be slightly below the inner diameter(s)  108   a  of the bearing assembly  200 . This may prevent damage to the axle  101  and bearing assembly  200 , as described above, as the substantially filled axle undercut more closely conforms to the diameter(s)  108   a  of the bearing assembly  200 . 
     According to various embodiments, the axle saddle system  100  comprises a saddle  110  and may comprise a saddle strap  112 , as shown in  FIG. 2 . 
     According to various embodiments, the saddle  110  is configured to substantially cover the axle undercut  107  over its surface area, and to substantially fill the axle undercut  107 , such that the substantially filled undercut has a profile  107   a  which is substantially level with the outboard bearing land  102  and the inboard bearing land  104 . 
     According to various embodiments, saddle  110  is configured to conform to the geometry of the axle undercut  107 . According to various embodiments, the axle undercut  107  has a circumferential perimeter, and may be cylindrical or conical (e.g., where the inboard bearing  206  has a larger diameter than the outboard bearing  204 ). According to various embodiments, the saddle  110  may have an axial length  124  approximately equal to the axial length  124   a  (see  FIG. 1A ) of the axle undercut  107 . According to various embodiments, the saddle  110  may wrap around a majority portion of the circumferential perimeter of the axle undercut  107 . According to various embodiments, the saddle  110  comprises a first saddle end  114  configured to abut the outboard transition wall  103 , and a second saddle end  116  configured to abut the inboard transition wall  105 . According to various embodiments, the saddle  110  may have a thickness  118  approximately equal to or slightly less than the radial span  120  ( FIG. 1A ) of the outboard transition wall  103  and/or radial span  122  ( FIG. 1A ) of the inboard transition wall  105 . In various embodiments, radial span  120  may equal the radial span  122 . In various embodiments, radial span  120  may not equal the radial span  122 , and thickness  118  may gradually transition from a thickness approximately equal to or slightly less than radial span  120  at first saddle end  114 , to a thickness approximately equal to or slightly less than radial span  122  at second saddle end  116 , or thickness  118  may be approximately equal to or slightly less than the lesser of radial span  120  and radial span  122 , according to various embodiments. According to various embodiments, saddle  110  may be formed from a metal such as stainless steel. 
     According to various embodiments, saddle  110  comprises an axial cut out portion or an axial split  126 , along the axial length  124  of the saddle  110 , for facilitating insertion of the saddle into the axle undercut  107 . According to various embodiments, axial split  126  may span between approximately 10° to 45° of the circumference of the saddle  110 . Thus, in describing the saddle  110  as configured to substantially cover the axle undercut  107  over its surface area, the term “substantially cover” may include a coverage spanning at least 315° of the perimeter of the surface area according to various embodiments. According to various embodiments, saddle  110  may be deformed to an open position for insertion by pulling apart the edges  127  of the axial split  126 , enabling the saddle  110  to spread open, and slip over the axle undercut  107 , then spring back into its natural shape. According to various embodiments, in the open position, saddle  110  may be deformed, such that axial split is approximately equal to the diameter  108   a  of the bearing assembly  200 . According to various embodiments, axial split  126  of the saddle  110  in its natural shape may span approximately 45° of the perimeter of the surface area of the axle undercut  107 . 
     According to various embodiments, saddle  110  of axle saddle system  100  is tightened around axle undercut  107  via saddle strap  112 . According to various embodiments, saddle strap  112  comprises a buckle  128  and strap end  129 . According to various embodiments, saddle strap  112  may be a band clamp or cable tie, or other similar closure device having low strap and buckle profiles. According to various embodiments the saddle strap  112  may be a stainless steel cable tie. Example of suitable saddle straps  112  having a low profile, flat head buckle (e.g. pawl and ratchet locking mechanism) may include various cable ties manufactured by Thomas and Betts and sold under the tradename TY RAP® or TY-MET®. According to various embodiments, saddle strap  112  may be installed by pulling the strap end  129  through buckle  128  to tighten its hold of the saddle  110  around the axle undercut  107 . According to various embodiments, an excess end portion of saddle strap  112  may be broken off after tightening (e.g by twisting the end of the saddle strap  112 , wherein saddle strap  112  is metallic). 
     According to various embodiments, saddle  110  comprises a strap channel  130  and a buckle cut out  140 . According to various embodiments, saddle strap  112  is configured to nest within the strap channel  130 , and buckle  128  is configured to nest within the buckle cut out  140  adjacent to the strap channel  130 . According to various embodiments, strap channel  130  forms a circumferential recess in saddle  110 , and the buckle cut out  140  is an extension of axial split  126 , as shown in  FIG. 2 . According to various embodiments, the thickness of saddle strap  112  and buckle  128  are less than the thickness  118  of the saddle  110 , such that saddle strap  112  and buckle  128 , situated within strap channel  130  and buckle cut out  140 , are flush and/or recessed with respect to an outer surface  150  of saddle  110 . 
     According to various embodiments, axle saddle system  100  comprises two or more saddle straps  112 , and saddle  110  comprises two or more strap channels  130 . According to various embodiments, two or more strap channels  130  include adjacent buckle cut outs  140  for each strap channel  130 , wherein the saddle straps  112  are configured to nest with strap channels  130 . In various embodiments, the axle saddle system  100  comprises 3 saddle straps  112 , and saddle  110  comprises 3 strap channels  130  and 3 buckle cut outs  140 , for the saddle straps  112 . 
     According to various embodiments, saddle  110  may further comprise a moisture draining system comprising drain holes  142  to prevent moisture (e.g., from condensation) from being trapped between the saddle  110  and axle undercut  107 . According to various embodiments, the saddle  110  may comprise a plurality of spaced apart drain holes  142  throughout the saddle  110 . In various embodiments, the saddle  110  includes 4 rows of 4 drain holes  142 , for a total of 16 drain holes  142  as shown in  FIG. 2 . 
     According to various embodiments, the axle saddle system  100  may comprise any number of the strap channels  130  and the buckle cut outs  140 , the drain holes  142 , different types and/or number of the saddle straps  112 , including embodiments without straps, and moisture drainage systems, etc. depending on design preferences, available materials, axle design, etc. 
     According to various embodiments, an axle method  400 , shown in  FIG. 4  comprises a first step of prying a saddle open (step  401 ), wherein the saddle comprises an axial split which enables the saddle to be deformed open. According to various embodiments, axle method  400  further comprises a next step of inserting the saddle over an undercut of a wheel axle (step  402 ). According to various embodiments, the wheel axle comprises an outboard bearing land and an inboard bearing land, wherein the undercut is situated between the outboard bearing land and the inboard bearing land and is tapered with respect to at least one of the outboard bearing land and the inboard bearing land. According to various embodiments, the saddle is configured to substantially fill the undercut, such that the substantially filled undercut is substantially level with the outboard bearing land and the inboard bearing land. According to various embodiments, axle method  400  further comprises a step of tightening the saddle around the undercut (step  403 ). According to various embodiments, at least one saddle strap may be used to tighten the saddle around the undercut for step  403 . According to various embodiments, the saddle strap comprises a buckle and a strap end, the axle method  400  further comprising a step of inserting the strap end through the buckle (step  405 ), and a step of pulling the strap end through the buckle to tighten the strap around the saddle (step  406 ). According to various embodiments, axle method  400  may further comprise a step of breaking off an excess portion of the strap (step  407 ), which is the portion of the strap adjacent the strap end which was pulled through the buckle in step  406 . According to various embodiments, the saddle may be left installed on the undercut, for example, after installation of a wheel. According to various embodiments, the saddle may be removed after the wheel has been installed. 
     Systems and methods are provided. In the detailed description herein, references to “various embodiments”, “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments. 
     Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the invention. The scope of the invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.