Abstract:
The present invention is generally directed towards systems for securely retaining an electric motor in a cycle fork, including: a surface feature and a slot, a motor with an axle positioned in the dropout, and a substantially flat insert disposed at least in part in the surface feature and including an opening into which the axle is at least in part positioned. Some embodiments may include a hub motor having an axle with a diameter of 12-14 mm with a non-round cross section with two flats on opposite sides, the axle being threaded; an aluminum fork including a dropout with a slot keyed to accept the axle, and a depression; a substantially flat metal plate 2-4 mm thick, positioned at least in part in the depression, and including an opening keyed to accept the axle; and a nut, threaded onto the axle.

Description:
FIELD OF THE INVENTION 
       [0001]    In general, the present invention is directed to an apparatus and system for connecting a front axle of an electric hub motor to a cycle frame. More specifically, the present invention is directed to a system for reinforcing a front cycle fork to withstand torsional forces exerted by a front electric motor, while providing a positive retention feature in accordance with various safety recommendations and requirements. 
       BACKGROUND 
       [0002]    The use of bicycles is known in the art. However, as urban areas become increasingly crowded, awareness of the environmental impact of internal combustion vehicles deepens, and the use internal combustion engines and other carbon-based energy sources becomes more expensive, the use and roles of bicycles has expanded. 
         [0003]    As the use and roles of bicycles have expanded, various “clean” versions of providing additional power to such cycles have been used. For example, the addition of an electric motor to a cycle may provide for additional power when required or useful, without contributing to air pollution, the use of carbon-based energy sources, etc. Electric cycles are known in the art and becoming increasingly commonplace. In general, an electric cycle is a cycle (for example, a bicycle, tricycle, or a four-wheel or quadracycle) with an integrated electric motor that can be used for propulsion. Electric cycles may take any variety of form, for example a pedal-assist (or “pedelec”) or a power-on-demand. Pedal-assist cycles may be particularly desirable due to often being classified as cycles, rather than low-powered mopeds or motorcycles. 
         [0004]    Various types of motors may be used in electric cycles, which may even be incorporated into one or more wheels of the cycle. Such motors may include, but are not limited to, hub motors that are disposed in the hub of a cycle wheel. However, because a hub motor exerts a rotational force on the axle of the wheel within which it is mounted, it causes a corresponding moment to be imparted to the axle. Accordingly, it is desirable to provide an axle for a hub motor that can withstand the forces exerted by the hub motor during repeated use and operation. 
         [0005]    As the role of cycles expands, it is known in the art to modify or design cycles in order to accommodate cargo. A cargo cycle is a cycle that has a specific cargo area for carrying items such as groceries, passengers, packages, etc. However, cargo bicycles suffer various drawbacks, at least one of which is the amount of effort required by an operator to manually power a fully-laden cargo cycle to its destination. In areas with hills, for example, the effort required to operate a cargo cycle may at times outweigh the benefit. Accordingly, a cargo cycle that assists the user in powering the cycle is desirable. 
         [0006]    If the cargo is held in a front portion of the cargo cycle, it may be advantageous or desirable to drive the front wheel of the cycle. However, front wheel forks are generally manufactured from softer and lighter materials (such as, but not limited to: aluminum, carbon fiber, titanium, and any combination or alloys of the same), which may not be suitable to handle the forces that may be exerted on the fork by a hub motor. Accordingly, it is desirable to provide a means of mounting a hub motor in a cycle fork generally manufactured from a softer or lighter material that will adequately resist torque applied to the fork from an electric motor. 
         [0007]    Moreover, various safety recommendations and/or requirements include a positive retention feature for the front wheel of cycles. For example, the U.S. Consumer Product Safety Commission requires that “[f]ront wheel hubs that do not use a quick release device must have a positive retention feature that keeps the wheel on when the locking devices are loosened.” (See 16 C.F.R. §1512.12(c)). In other words, a front wheel must remain in place even if axle nuts are loose. Accordingly, it is desirable to provide a motor mount for a front cycle fork that remains positively retained even if the axle nuts are loose. 
         [0008]    In addition, while various axle retainers for hub motors exist in the prior art, such retainers generally require at least two fasteners, thereby causing additional inconvenience during any removal and/or replacement of a wheel equipped with a hub motor. 
       SUMMARY OF THE INVENTION 
       [0009]    Aspects in accordance with some embodiments of the present invention may include a system for securely retaining an electric motor in a cycle fork, comprising: the fork, including a dropout comprising: a surface feature; and a slot; the motor, comprising an axle positioned in the dropout; and a substantially flat insert, disposed at least in part in the surface feature and comprising an opening, the axle being positioned at least in part in the opening. 
         [0010]    Other aspects in accordance with some embodiments of the present invention may include a system for securely retaining an electric motor in a cycle fork, comprising: a hub motor comprising an axle with a specific cross section, the axle being at least in part threaded; a fork comprising a fork dropout with a slot keyed to accept the specific cross section of the axle and a depression disposed thereon; a substantially flat insert comprised at least in part of metal, disposed at least in part in the depression, and comprising an opening keyed to accept the specific cross section of the axle; and a nut, threaded onto the axle and at least partially holding the insert in the depression. 
         [0011]    Some aspects in accordance with some embodiments of the present invention may include a system for securely retaining an electric hub motor in a cycle fork, comprising: a hub motor having an axle with a diameter of 12 mm or 14 mm with a non-round cross section comprising two flats on opposite sides, the axle being at least in part threaded; an aluminum fork comprising: a fork dropout with a slot keyed to accept the non-round cross section of the axle; and a depression; a substantially flat metal plate with a thickness between 2 mm and 4 mm, positioned at least in part in the depression, and comprising an opening keyed to accept the non-round cross section of the axle; and a nut, threaded onto the axle. 
         [0012]    These and other aspects will become apparent from the following description of the invention taken in conjunction with the following drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present invention can be more fully understood by reading the following detailed description together with the accompanying drawings, in which like reference indicators are used to designate like elements. The accompanying figures depict certain illustrative embodiments and may aid in understanding the following detailed description. Before any embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The embodiments depicted are to be understood as exemplary and in no way limiting of the overall scope of the invention. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The detailed description will make reference to the following figures, in which: 
           [0014]      FIG. 1  illustrates an exploded view of a front axle insert for strengthening a cycle fork and positively retaining a front wheel, in accordance with some embodiments of the present invention. 
           [0015]      FIG. 2  depicts an assembled system for strengthening a cycle fork and positively retaining a front wheel, in accordance with some embodiments of the present invention. 
           [0016]      FIG. 3  illustrates an exploded view of a front axle insert for strengthening a cycle fork and positively retaining a front wheel, in accordance with some embodiments of the present invention. 
           [0017]      FIG. 4  depicts an assembled system for strengthening a cycle fork and positively retaining a front wheel, used with a specialized fork for a cargo cycle, in accordance with some embodiments of the present invention. 
           [0018]      FIG. 5  depicts an assembled system for strengthening a cycle fork and positively retaining a front wheel, used with a suspension fork, in accordance with some embodiments of the present invention. 
       
    
    
       [0019]    Before any embodiment of the invention is explained in detail, it is to be understood that the present invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The present invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    The matters exemplified in this description are provided to assist in a comprehensive understanding of various exemplary embodiments disclosed with reference to the accompanying figures. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the exemplary embodiments described herein can be made without departing from the spirit and scope of the claimed invention. Descriptions of well-known functions and constructions are omitted for clarity and conciseness. Moreover, as used herein, the singular may be interpreted in the plural, and alternately, any term in the plural may be interpreted to be in the singular. Note that the term “cycle” may include a bicycle, tricycle, pedelec, moped, or motorcycle. 
         [0021]    With reference to  FIG. 1 , a front axle insert system  10  for strengthening a cycle fork and positively retaining a front wheel, in accordance with some embodiments of the present invention will now be discussed. The system  10  may comprise a hub motor  110 , a fork  120 , a metal insert  130 , an axle nut  140 , and an axle  150 . In general, the hub motor  110  comprise an outer surface or rim  111  that may, in accordance with some embodiments of the present invention, comprise a plurality of attachments for spokes. The hub motor  110  may be mounted in a slot or opening in the fork  120 . More specifically, fork  120  may comprise a fork dropout  121 , which may be a substantially flat or planar portion of the fork  120  onto which a wheel may be mounted. The axle  150  may positioned in the slot or opening in the fork dropout  121 , and may be held in place by a retention device, such as axle nut  140 . Note that it is contemplated that the axle  150  may be threaded or otherwise configured to mechanically receive and/or attach to the axle nut  140 . 
         [0022]    Note that axle  150  may be configured as a substantially cylindrical axle with flats  151  disposed thereon. Such flats  151  may be positioned in the slot or opening in the fork dropout  121  such that the front axle  150  may not freely rotate within the slot or opening in the fork dropout  121 . The axle  15  may be of any size, though it is contemplated that the axle may be approximately twelve (12) or fourteen (14) millimeters in diameter, as this is a standard size. As the hub motor may provide a driving force to the front wheel, such retention may prevent slipping or rotation of the front axle  150 , which may result in reduced drive force to the wheel. 
         [0023]    In order to strengthen the fork  120  and/or the fork dropout  121  in order to prevent damage and/or unnecessary wear or fatigue caused by forces and torque applied from the hub motor  110 , a metal insert  130  may be used. Metal insert  130  may be comprised of any suitable material that may resist the forces from the hub motor without excessive wear. Metal insert  130  may be of any suitable thickness, though the present invention contemplates a thickness between of two (2) to four (4) millimeters thick, and in accordance with some embodiments, a thickness of approximately three (3) millimeters. Metal insert  130  may comprise an opening  131  that may include flats in order to align with the axle  150 . Metal insert  130  may be positioned in a depression  122  in the fork dropout  121 . The depression  122  may prevent the metal insert  130  from rotating with the axle  150 , and the force of any rotation may be applied from the metal insert  130  throughout the fork dropout  121 . 
         [0024]    Note that the fork dropout  121  may include additional surface features to support, connect, or hold in place the metal insert  130 . 
         [0025]    During operation, when the hub motor  110  applies a force to the rim  111  thereby rotating the wheel, an opposite force may be applied to the axle  150 . The axle  150  may be prevented from rotating from the motor torque due to the flats  151  on the axle  150  being held by a corresponding flat on the fork dropout  121  and/or the flats  131  on the metal insert  130 . The metal insert  130  may be prevented from rotating due to the depression  122  in the fork dropout  121 . In this manner, the various forces that are applied to the cycle fork  120  due to the use of the hub motor  110  may be adequately handled by the fork  120  without excessive wear, and without requiring the entire fork  120  to be comprised of a stronger material. Accordingly, fork  120  may be manufactured from, for example, aluminum or a composite material, with a metal insert used to strengthen the connection with the hub motor. 
         [0026]    In addition, the depression  122  in the fork dropout  121  may substantially surround the metal insert  130  (other than, for example, the slot into which the axle may be mounted). This substantial surrounding may prevent the metal insert  130  from easily sliding out of place, even if the axle nut  140  is loosened. If the metal insert  330  is held in place, the front wheel and hub motor may be correspondingly held in place. Accordingly, the metal insert  130  may therefore also provide a positive retention means that may retain the front wheel in place even if the axle nuts are loosened. 
         [0027]    With reference to  FIG. 2 , an assembled system  20  for strengthening a cycle fork and positively retaining a front wheel, in accordance with some embodiments of the present invention will now be discussed. The system  20  may comprise a hub motor  210 , a fork  220 , a metal insert  230 , an axle nut  240 , and an axle  250 . In general, the hub motor  210  may comprise a plurality of attachments for spokes  212 . The fork  220  may comprise a top portion  221 , which may be rotatably attached to a cycle frame and rotated to effectuate steering, a right fork  222  and a left fork  223 . Each of the right fork  222  and left fork  223  may comprise a fork dropout  224  that may be, for example, substantially planar. The hub motor  210  may be mounted in a slot or opening in the fork dropout  224 . The axle  250  may positioned in a slot or opening in the fork dropout  224 , and may be held in place by a retention device, such as axle nut  240 . Note that it is contemplated that the axle  250  may be threaded or otherwise configured to mechanically receive and/or attach to the axle nut  240 . 
         [0028]    Axle  250  may be configured as a substantially cylindrical axle with flats disposed thereon. Such flats may be positioned in the slot or opening in the fork dropout  224  such that the front axle  250  may not freely rotate within the slot or opening in the fork dropout  224 . As the hub motor  210  may provide a driving force to the front wheel, such retention may prevent slipping or rotation of the front axle  250 , which may result in reduced drive force to the wheel. 
         [0029]    Metal insert  230  may be used to prevent damage and/or unnecessary wear or fatigue caused by forces and torque applied from the hub motor  210 , and may be comprised of any suitable material that may resist the forces from the hub motor without excessive wear. Metal insert  230  may comprise an opening that may include flats in order to align with the axle  250 . Metal insert  230  may be positioned in a depression  225  in the fork dropout  224 . The depression  225  may prevent the metal insert  230  from rotating with the axle  250 , and the force of any rotation may be applied from the metal insert  230  throughout the fork dropout  224 . 
         [0030]    As with the system  10  discussed above, during operation, when the hub motor  210  applies a force to rotate the wheel, an opposite force may be applied to the axle  250 . The axle  250  may be prevented from rotating from the motor torque due to the flats on the axle  250  being held by a corresponding flat on the fork dropout  224  and/or the flats on the metal insert  230 . The metal insert  230  may be prevented from rotating due to the depression  225  in the fork dropout  224 . In this manner, the various forces that are applied to the cycle fork drop outs  224  due to the use of the hub motor  210  may be adequately handled by the fork without excessive wear, and without requiring the entire fork  220  to be comprised of a stronger material. 
         [0031]    With reference to  FIG. 3 , an exploded view of a system  30  for a front axle insert for strengthening a cycle fork and positively retaining a front wheel, in accordance with some embodiments of the present invention will now be discussed. Similar to  FIGS. 1 and 2  discussed above, the system  30  in  FIG. 3  may comprise a hub motor  310 , a fork  320 , metal inserts  330 , axle nuts  340 , and an axle  350 . The fork  320  may comprise a top portion  321 , which may be rotatably attached to a cycle frame and rotated to effectuate steering, a right fork  322  and a left fork  323 . Each of the right fork  322  and left fork  323  may comprise a fork dropout  324  that may be, for example, substantially planar. The hub motor  310  may be mounted in a slot or opening in the fork dropout  324 . The axle  350  may positioned in a slot or opening in the fork dropout  324 , and may be held in place by a retention device, such as axle nut  340 . Note that it is contemplated that the axle  350  may be threaded or otherwise configured to mechanically receive and/or attach to the axle nut  340 . 
         [0032]    Axle  350  may be configured as a substantially cylindrical axle with flats disposed thereon. Such flats may be positioned in the slot or opening in the fork dropout  324  such that the front axle  350  may not freely rotate within the slot or opening in the fork dropout  324 . As the hub motor  310  may provide a driving force to the front wheel, such retention may prevent slipping or rotation of the front axle  350 , which may result in reduced drive force to the wheel. 
         [0033]    Metal insert  330  may be used to prevent damage and/or unnecessary wear or fatigue caused by forces and torque applied from the hub motor  310 , and may be comprised of any suitable material that may resist the forces from the hub motor without excessive wear. Metal insert  330  may comprise an opening that may include flats in order to align with the axle  350 . Metal insert  330  may be positioned in a depression  325  in the fork dropout  324 . The depression  325  may prevent the metal insert  330  from rotating with the axle  350 , and the force of any rotation may be applied from the metal insert  330  throughout the fork dropout  324 . 
         [0034]    As with the systems  10  and  20  discussed above, during operation, when the hub motor  310  applies a force to rotate the wheel, an opposite force may be applied to the axle  350 . The axle  350  may be prevented from rotating from the motor torque due to the flats on the axle  350  being held by a corresponding flat on the fork dropout  324  and/or the flats on the metal insert  330 . The metal insert  330  may be prevented from rotating due to the depression  325  in the fork dropout  324 . In this manner, the various forces that are applied to the cycle fork drop outs  324  due to the use of the hub motor  310  may be adequately handled by the fork without excessive wear, and without requiring the entire fork  320  to be comprised of a stronger material. 
         [0035]    In addition, the depression  325  in the fork dropout  324  may substantially surround the metal insert  330  (other than, for example, the slot into which the axle may be mounted). This substantial surrounding may prevent the metal insert  330  from easily sliding out of place, even if the axle nut  340  is loosened. If the metal insert  330  is held in place, the front wheel and hub motor may be correspondingly held in place. Accordingly, the metal insert  330  may therefore also provide a positive retention means that may retain the front wheel in place even if the axle nuts are loosened. 
         [0036]    With reference to  FIG. 4 , an assembled system  40  for strengthening a cycle fork and positively retaining a front wheel, used with a specialized fork for a cargo cycle, in accordance with some embodiments of the present invention will now be discussed. System  40  may generally comprise a hub motor  410 , a fork  420 , a metal insert  430 , an axle nut  440  and an axle  450 . System  40  may additionally comprise a protrusion  460  which may be attached to the fork  420 . Protrusion  460  may be attached to the fork  420  proximate to the fork dropout  421 , and may extend substantially parallel to the fork  420 . Protrusion  460  may be utilized to connect to pushrods and/or other types of steering components in order turn the fork  420  and the front wheel and motor  410 . In the case of a cargo cycle, protrusion  460  may be utilized to receive steering inputs from a separate steering assembly. 
         [0037]    Regardless of the form of the fork  420 , the system  40  operates similarly to the systems discussed above. Metal insert  430  may be utilized to sit in a depression in the fork dropout  421 , and may be configured with flats keyed to fit axle  450  and prevent rotation of the axle  450  within the metal insert  430 . Metal insert  430  and the hub motor  410  may be held in place in the fork dropout  421  by any retention means, including but not limited to an axle nut  440  that may be threaded onto the axle  450 . As the hub motor  410  applies a force to a wheel to rotate such wheel, an opposite force or toque may be resultant on the fork dropout  421 . To prevent the fork dropout  421  from rounding out, wearing, or otherwise distorting or failing to properly hold the axle in place and prevent rotation, the metal insert  430  may be used. The torque of rotation of the hub motor  410  may be received by the metal insert  430 , which may be hard enough to prevent rounding out of the flats. The metal insert  430  may itself be prevented from rotating by being positioned in a depression in the fork dropout  421 . The use of the metal insert  430  may provide a means to prevent the fork dropout  421  slot or hole from wearing, as well as provide a means to distribute the force received from the hub motor  410  during operation across a larger area of the depression in the fork dropout  421 . 
         [0038]    In addition, as discussed above the depression in the fork dropout  421  may substantially surround the metal insert  430  (other than, for example, the slot into which the axle may be mounted). This substantial surrounding may prevent the metal insert  430  from easily sliding out of place, even if the axle nut  440  is loosened. If the metal insert  430  is held in place, the front wheel and hub motor  410  may be correspondingly held in place. Accordingly, the metal insert  430  may therefore also provide a positive retention means that may retain the front wheel in place even if the axle nuts  440  are loosened. 
         [0039]    With reference to  FIG. 5 , an assembled system  50  for strengthening a cycle fork and positively retaining a front wheel, used with a suspension fork, in accordance with some embodiments of the present invention will now be discussed. Much as discussed above, the system  50  may comprise a hub motor  510  mounted in a fork  520 . The fork  520  may be a suspension fork, for example, comprising hydraulic cushioning or spring resistance between the wheel and the attachment to a frame. In this manner, rider comfort and controllability of the cycle may be maintained even in rough terrain. 
         [0040]    The system  50  may further comprise a metal insert  530  which may be positioned around an axle  540 . An axle nut  550  or other attachment device may be used to retain the hub motor  510  in the proper position in the fork  520 . Though not depicted in detail, the operation of the system  50  may be similar to that discussed above with regard to systems  10 ,  20 ,  30 ,  40 , in that the metal insert  530  may be used to prevent rotation of the axle by dispersing any torque received from the hub motor  510  throughout the fork dropout  521 . Moreover, the metal insert  530  may be used to provide a positive retention system to the hub motor  510  and front wheel, thereby providing safety redundancy in accordance with various safety requirements and/or recommendations. 
         [0041]    It will be understood that the specific embodiments of the present invention shown and described herein are exemplary only. Numerous variations, changes, substitutions and equivalents will now occur to those skilled in the art without departing from the spirit and scope of the invention. For example, the axle may be maintained in place by various attachment devices other than a nut. The metal insert of the present invention may be utilized directly with a fork, and no fork dropout may be required. The metal plate may take any form or shape that may be convenient to match the fork or fork dropout into which it is mounted. Similarly, rather than having the metal plate or insert being positioned in a depression, it may be held in place between or by various protrusions on the fork or fork dropouts. Alternatively, the metal plate or insert may comprise one or more orifices or holes that may fit over protrusions on the fork or fork dropout, or may comprise one or more tabs that may be inserted into one or more orifices or holes in the fork or fork dropouts. Moreover, the present invention can be used for traditional wheel systems to provide a positive retention means without the use of a hub motor. For example, the present invention may permit front forks to be manufactured from lightweight and softer materials while providing an adequate attachment for a front wheel. Similarly, the specific shapes shown in the appended figures and discussed above may be varied without deviating from the functionality claimed in the present invention. Accordingly, it is intended that all subject matter described herein and shown in the accompanying drawings be regarded as illustrative only, and not in a limiting sense, and that the scope of the invention will be solely determined by the appended claims.