Patent Publication Number: US-9427613-B2

Title: Jump rope handle with multiple bearings

Description:
BACKGROUND 
     1. Field 
     The present invention relates to jump rope handles. More particularly, embodiments of the present invention relate to jump rope handles having a plurality of bearings rotationally coupling a handle head with a handle grip. 
     2. Background Information 
     Jump ropes are exercise equipment used for play, exercise, training, and sport. Referring to  FIG. 1 , a pictorial view of a jumper using a jump rope is shown. A typical jump rope includes a rope  100  with a handle  102  at either end for a jumper  104  to grip and control the swinging of the rope. In the sport of speed rope skipping, a jumper may try to complete as many jumps as possible within a particular amount of time. For example, the jumper could complete as many as one hundred jumps during a thirty second interval. To achieve this intensity of jumping, a specialized jump rope, sometimes referred to as a speed rope, may be required. 
     Referring to  FIG. 2 , a cross-sectional view of a portion of a jump rope handle is shown. A typical speed rope handle  102  may include a handgrip  202  for a jumper to hold and a nut  204  fixed to rope  100 . Nut  204  may rotate relative to handgrip  202  such that the entire rope  100  swings about a handle axis. This differs from conventional jump rope handles in which a portion of rope  100  remains fixed relative to handgrip  202  and a portion of rope  100  swings about the handle axis such that a region of localized cyclic bending stresses occurs in rope  100  between the portions. By rotationally decoupling rope  100  from handgrip  202  as shown in  FIG. 2 , rope speed and control may be improved to facilitate faster jumping. 
     In a typical speed rope, nut  204  is fixed to a screw  206  that passes through a retaining element engaged with handgrip  202 , e.g., screw  206  may extend through a bushing  212  pressed into an end of handgrip  202 . Nut  204  may be threaded onto a threaded portion  208  of screw  206  to retain a screw shank  210  within bushing  212 , allowing shank  210  and nut  204  to rotate freely relative to handgrip  202 . However, during use, as rope  100  swings quickly around the jumper, transverse loading in a radial direction may be applied to the threaded portion  208  of screw  206  by rope  100 , and therefore, the cantilevered screw  206  may transmit both transverse and axial loads, as well as substantial torque, to bushing  212 . More particularly, the cantilever load placed on screw  206  by rope  100  may result in loading, and thus, friction between screw  206  and bushing  212 . This friction may reduce an achievable jumping speed. Furthermore, axial and torsional loading of bushing  212  can result in material stresses that bushing  212  is not designed to withstand, which may lead to failure of bushing  212 . Thus, conventional speed ropes may not be durable and/or may prevent a jumper from reaching their performance goal. 
     SUMMARY OF THE DESCRIPTION 
     A jump rope handle is disclosed. In an embodiment, a jump rope handle includes a grip having a shaft, and a head rotationally coupled with the grip by a plurality of bearings. Each of the plurality of bearings may include a bearing inner surface adjacent to the shaft and a bearing outer surface adjacent to the head. Furthermore, the head may include a rope landing intermediate to the plurality of bearings. For example, the rope landing may be axially centered between the plurality of bearings. Thus, transverse loading on the head that occurs, for example, during speed rope skipping, may be equally or nearly equally shared between the plurality of bearings. 
     In an embodiment, the plurality of bearings include a distal bearing and a proximal bearing that are each selected from a group consisting of a plain bearing, a rolling bearing, a fluid bearing, and a magnetic bearing. For example, at least one of the distal bearing or the proximal bearing may include a rolling bearing having an inner race coupled with the shaft at the bearing inner surface and an outer race coupled with the head at the bearing outer surface. Furthermore, the rolling bearing may include a thrust bearing to support axial loading of the bearing system. For example, the proximal bearing may be a thrust bearing. Alternatively or additionally, at least one of the distal bearing or the proximal bearing may include a plain bearing having the bearing outer surface and the bearing inner surface. 
     In an embodiment, the shaft is integral with the grip. For example, the shaft may include a threaded base configured to be threaded into the grip. Alternatively, the shaft may include a boss configured to be pressed into the grip. Furthermore, in an embodiment, the grip includes a foot having a foot outer surface tapering inward in a distal direction. 
     In an embodiment, a speed rope includes a handle having a grip that includes a shaft, a head rotationally coupled with the grip by a plurality of bearings, and a rope landing. Each of the plurality of bearings may include a bearing inner surface adjacent to the shaft and a bearing outer surface adjacent to the head. The speed rope may include a rope having a first end opposite of the rope landing from a second end, and a rope retainer may be coupled with the rope opposite of the rope landing from the second end to secure the rope in the head. 
     In an embodiment, the rope landing of the speed rope is intermediate to the plurality of bearings. For example, the rope landing may be axially centered between the plurality of bearings. Thus, transverse loading on the head that occurs, for example, during use of the speed rope, may be equally or nearly equally shared between the plurality of bearings. 
     In an embodiment, the plurality of bearings include a distal bearing and a proximal bearing selected from a group consisting of a plain bearing, a rolling bearing, a fluid bearing, and a magnetic bearing. For example, at least one of the distal bearing or the proximal bearing of the speed rope may include a rolling bearing having an inner race coupled with the shaft at the bearing inner surface and an outer race coupled with the head at the bearing outer surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a pictorial view of a jumper using a jump rope. 
         FIG. 2  is a cross-sectional view of a portion of a jump rope handle. 
         FIG. 3  is a top view of a jump rope handle in accordance with an embodiment. 
         FIG. 4  is a side view of a jump rope handle in accordance with an embodiment. 
         FIG. 5  is a cross-sectional view, taken about line A-A of  FIG. 4 , of a jump rope handle in accordance with an embodiment. 
         FIG. 6  is a cross-sectional view, taken from Detail A of  FIG. 5 , of a distal portion of a jump rope handle in accordance with an embodiment. 
         FIG. 7  is a cross-sectional view of an alternative embodiment of a distal portion of a jump rope handle in accordance with an embodiment. 
         FIGS. 8A-8C  are exploded views of a jump rope handle in accordance with an embodiment. 
         FIG. 9  is a perspective view of a distal portion of a jump rope handle in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention describe jump rope handles. While some embodiments of the present invention are described with specific regard to speed rope training, the embodiments of the invention are not so limited and certain embodiments may also be applicable to other activities, such as jump rope skipping. 
     In various embodiments, description is made with reference to the figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations and processes, in order to provide a thorough understanding of the present invention. In other instances, well-known processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the present invention. Reference throughout this specification to “one embodiment,” “an embodiment”, or the like, means that a particular feature, structure, configuration, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase “one embodiment,” “an embodiment”, or the like, in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments. 
     In an aspect, embodiments describe a jump rope handle having a plurality of bearings rotationally coupling a head with a grip. In an embodiment, the plurality of bearings include one or more rotating bearings having an inner race coupled with the grip and an outer race coupled with the head. The rotating bearings may support the head at either end on the grip such that the head is only in contact with the outer race of the bearings. Furthermore, in an embodiment, an inner race of each bearing is only in contact with a shaft integral with the grip. Thus, a rotating mass of the handle and friction between handle components may be decreased to improve rope rotation speed. 
     In another aspect, embodiments describe a jump rope handle having a rope landing intermediate to a plurality of bearings that rotationally couple a head with a grip. More particularly, a rope may be secured to the head axially between a distal bearing and a proximal bearing. Accordingly, as the head rotates around the grip during use, the rope may apply a transverse load in a radial direction at the rope landing intermediate to the bearings. In an embodiment, since the rope is secured between the bearings, e.g., at an axially centered location between the bearings, the transverse load may be shared equally by the bearings and/or transverse loading on the bearings may be in a same direction. Furthermore, axial loading of the bearings due to an axial load component of the rope during use may be shared by both bearings. By distributing loading equally on the bearings, maximum loading applied to any one of the bearings may be reduced, and thus, the life of the bearing system may be extended. 
     Referring to  FIG. 3 , a top view of a jump rope handle is shown in accordance with an embodiment. A handle  300  may be a jump rope handle and or may be particularly well-suited for speed rope jumping. That is, handle  300  may be a speed rope handle designed for high intensity jump roping. Accordingly, handle  300  may include a grip  302  and a head  304  coaxially aligned along a central axis  306 . Head  304  may be located near a distal end  308  of handle  300  and a foot  310  may be located at a proximal end  312  of handle  300 , opposite from distal end  308 . During use, a jumper may hold grip  302  to control rotation of head  304  about central axis  306 . More particularly, head  304  may include features to secure a rope relative to head  304  along a rope path  314 , and thus, a jumper may control rotation of the head  304  relative to grip  302 , and swinging of the rope about central axis  306 , by manipulating grip  302 . 
     In an embodiment, a rope may pass through head  304  along a rope path  314  that is transverse to central axis  306 . For example, rope path  314  may follow a hole drilled or otherwise bored through head  304 . The hole may be radially offset from central axis  306 . Thus, the hole may have an entry port forming a rope landing  315  through which the rope may be inserted and passed along rope path  314 . The rope may exit head  304  at a rope retainer slot  316 , which may form a second opening of the hole. After passing the rope through the hole, the rope may be secured relative to head  304 . For example, a knot may be tied at an end of the rope and/or a rope fastener may be affixed to the rope such that the knot or the rope fastener resist movement through the hole at rope retainer slot  316 . In an embodiment, as the rope swings about a jumper, the rope may apply a radial load at rope landing  315 , producing a transverse load on head  304 . Rope landing  315  may include a wider opening than rope retainer slot  316  to provide a strain relief for the rope that allows the rope to bend at rope landing  315  without being abraded by head  304 . In an embodiment, edges of rope landing  315  and rope retainer slot  316  may be deburred, chamfered, or otherwise softened to further mitigate the risk of abrading the rope through extended use. 
     Referring to  FIG. 4 , a side view of a jump rope handle is shown in accordance with an embodiment. Handle  300  is shown in an assembled state with head  304  axially aligned with grip  302 . More particularly, head  304  may be spaced apart from grip  302  by a shoulder  402  but retained adjacent to grip  302  by a retaining clip  404 . Furthermore, head  304  may include a rope guide  406  passing through a hole in head  304  along rope path  314 . Rope guide  406  may be radially offset from central axis  306 . Thus, a rope may pass through rope guide  406  and be secured by a rope fastener set within rope retainer slot  316 , as described above. 
     Referring to  FIG. 5 , a cross-sectional view of a jump rope handle, taken about line A-A of  FIG. 4 , is shown in accordance with an embodiment. Handle  300  may include grip  302 , foot  310 , and a shaft  502  arranged longitudinally about central axis  306 . In an embodiment, head  304  is rotationally supported on shaft  502  by a plurality of bearings, such as a proximal bearing  504  and a distal bearing  506 . More particularly, head  304  may be rotationally decoupled from shaft  502  by the bearings such that a torque applied to head  304 , for example, by momentum of a swinging rope, is not transmitted to shaft  502 . 
     Referring to  FIG. 6 , a cross-sectional view of a distal portion of a jump rope handle, taken from Detail A of  FIG. 5 , is shown in accordance with an embodiment. In an embodiment, a bearing system includes multiple bearings separated along central axis  306 . For example, the bearing system may include proximal bearing  504  supporting head  304  near a proximal end and distal bearing  506  supporting head  304  near a distal end. More particularly, a head inner surface  608  may be supported by a bearing outer surface  609  of each bearing, and a shaft outer dimension  610  may support a bearing inner surface  611  of each bearing. Thus, the bearing system may maintain a radial and axial alignment between head  304  and shaft  502 , while permitting head  304  and shaft  502  to rotate freely relative to each other. 
     In an embodiment, head  304  may be directly supported by a bearing positioned on shaft  502 . That is, each bearing may directly couple head  304  with shaft  502 , while also rotationally decoupling head  304  from  502 . More particularly, bearing outer surface  609  and bearing inner surface  608  may be coupled with head  304  and shaft  502 , respectively, at locations that are axially aligned with each other. These locations, which may be for example where an inner race of a bearing presses against shaft  502  and an outer race of the bearing presses against head  304 , may be radially offset from each other by a thickness of the bearing ring, e.g., a distance between the bearing inner and outer surfaces. Furthermore, in an embodiment, head  304  is directly supported around shaft  502  by multiple bearings that are located distal to grip  302 . 
     In an embodiment, the bearing system includes at least one bearing designed to support radial loading applied to head  304 . For example, in an embodiment, each bearing is a rolling bearing having an outer race  602  and an inner race  604  that are rotationally decoupled from each other by one or more intermediate rollers  606 . Thus, the outer race  602  may rotate around the inner race  604  with minimal friction and at high speeds, due to rolling of the intermediate rollers  606 . Intermediate rollers  606  may be chosen depending on the anticipated speed and loading conditions, but may for example include balls, cylindrical rollers, spherical rollers, tapered rollers, or needle rollers. Thus, the bearing system may support radial loading applied to head  304  by a swinging rope while enabling rapid spinning of head  504  about shaft  502 . 
     In an embodiment, the bearing system may also include bearings that support non-radial loading of head  304 . For example, at least one of the bearings may be a thrust bearing designed to support axial loading applied to head  304  by a swinging rope. Thus, although loading on head  304  during use may primarily be transverse loading in a radial direction, the bearing system may be designed to support both transverse and axial loads. In an embodiment, proximal bearing  504  supports most of the axial loading that occurs during use, and therefore, proximal bearing  504  may be a thrust bearing such as a thrust ball bearing, a spherical roller thrust bearing, a tapered roller thrust bearing, or a cylindrical roller thrust bearing. 
     In addition to supporting alternative loading schemes, bearings in the bearing system may be of different types. For example, one or more of the bearings may be a plain bearing having bearing outer surface  609  coupled with head inner surface  608  and bearing inner surface  611  coupled with shaft  502 . Either or both of the bearing surfaces may be glidingly coupled with respective head or shaft surfaces such that the respective head and/or shaft surfaces slide over the plain bearing surface. Furthermore, either of bearing outer surface  609  or bearing inner surface  611  may be fixed relative to a respective head or shaft surface. The plain bearing may be made from, or coated with, a material that exhibits a low coefficient of friction in combination with the respective surfaces, e.g., polytetrafluoroethylene. In addition to plain bearings, the bearing system may also incorporate one or more fluid bearings or magnetic bearings. Thus, the bearing system may include at least two, and in some cases more than two, bearings of a same or different type to support axial and radial loading of head  304 . 
     In an embodiment, a head inner surface  608  may be coupled with outer race  602  of each bearing in the bearing system. For example, each outer race  602  may be pressed into a counterbore in head  304  such that a bearing outer surface  609  forms a press fit with head inner surface  608  to securely fasten outer race  602  with head  304 . Similarly, each inner race  604  may be fastened with a shaft outer dimension  610 . For example, shaft  502  may be pressed through each inner race  604  such that a bearing inner surface  611  forms a press fit with shaft outer dimension  610  to securely fasten inner race  604  to shaft  502 . 
     Given that proximal bearing  504  and distal bearing  506  may rotationally support head  304  at either end relative to shaft  502 , in an embodiment, head  304  is rotationally decoupled from shaft  502  and is supported across a span  612  between proximal bearing  504  and distal bearing  506 . More particularly, head  304  may only be in contact with the outer races  602  of each bearing in handle  300 . Accordingly, in an embodiment, any loading applied to head  304  by a swinging rope will be resisted solely by the bearings in the bearing system. A magnitude and direction of loading on each of the bearings may depend on the location at which the rope applies a load to head  304 . 
     In an embodiment, rope retainer slot  316  and/or rope landing  315  may be longitudinally, e.g., axially, between proximal bearing  504  and distal bearing  506  such that the rope applies a load to head  304  within span  612 . In such case, because the net torque on the bearing system may usually be zero, loading applied to proximal bearing  504  and distal bearing  506  will be in a same direction, i.e., in a direction opposite to the transverse loading from the rope. The magnitude of loading seen by each bearing will depend on the distance each bearing is set away from the point at which rope applies a transverse load. For example, when rope landing  315 , and therefore transverse loading, is axially centered within span  612 , reaction forces on proximal bearing  504  and distal bearing  506  will be substantially equal to each other and the respective reaction forces will be approximately half of the transverse load magnitude. That is, the bearings in the bearing system will share the transverse loading equally. Alternatively, as the rope landing  315  moves closer to one of the bearings, the other bearing will share a disproportionately higher amount of the transverse loading, i.e., one bearing will see a higher reaction force than the other. Thus, a location of rope landing  315 , rope retainer slot  316 , and rope guide  406  may be altered to change the location of transverse loading from rope, and to tune load sharing by the bearings. More particularly, in an embodiment, rope path  314  may pass through head  304  at a location axially between the bearings to evenly distribute the transverse load amongst the bearings such that maximum loading of any one bearing may be reduced, and therefore, the life of all bearings in the bearing system may be extended. 
     Referring to  FIG. 7 , a cross-sectional view of an alternative embodiment of a distal portion of a jump rope handle is shown in accordance with an embodiment. In an embodiment, transverse loading applied by a rope may not be equally shared by the bearings in the bearing system. For example, rope retainer slot  316  and/or rope landing  315  may be located in head  304  distal to distal bearing  506 . That is, rope landing  315 , and thus the location at which transverse loading from the rope is applied, may be located outside of span  612 , e.g., distal to distal bearing  506  or proximal to proximal bearing  504 . As a result, rather than exhibiting a loading profile of a simply supported beam between the bearings, head  304  may exhibit a loading profile of a supported beam with one end cantilevered beyond a bearing. Accordingly, while net torque on the bearing system may usually be zero, summing moments about the bearings reveals that reaction forces on distal bearing  506  will be opposite to reaction forces on proximal bearing  504 . More particularly, distal bearing  506  may support a reaction force opposite to the transverse loading from the rope, and proximal bearing  504  may support a reaction force in the same direction as the transverse loading from the rope. Furthermore, distal bearing  506  may have a higher reaction force applied to it than the reaction force applied to proximal bearing  504 . Thus, in an embodiment, locating rope retainer slot  316  and/or rope landing  315  outside of span  612 , e.g., distal to distal bearing  506  or proximal to proximal bearing  504 , may create an asymmetry in the bearing system, both in loading magnitude and direction on respective bearings. Nonetheless, the maximum loading applied to either bearing may be less than the loading experienced by bearings in existing jump rope handles, such as the loading described with respect to  FIG. 2 , above. Furthermore, a speed rope handle configured as shown in  FIG. 7  may allow for a reduction in cross-sectional profile, since the rope guide  406  may pass more closely to central axis  306 , i.e., may be moved closer to central axis  306 , potentially resulting in a more compact handle form factor. 
     Referring to  FIG. 8A , an exploded view of a jump rope handle is shown in accordance with an embodiment. Grip  302  may include features to allow a jumper to securely hold handle  300  during high intensity jumping. For example, an outer surface of grip  302  may be shaped to facilitate handling, e.g., may be cylindrical or contoured to conform to a hand grip. The outer surface may also be modified to improve handling, such as by incorporating knurled or roughened surfaces. Furthermore, grip may be overmolded, coated, or covered with materials that are easy to grip, such as foam, rubber, etc. To further improve handling, handle  300  may include foot  310  to prevent handle  300  from being pulled from a jumper&#39;s hand by the momentum of a swinging rope. Foot  310  may include a tapered region  802  extending proximally from grip  302 , such that a proximal end of foot  310  has a greater profile than a distal end of foot  310 . That is, foot  310  may have a frustoconical outer surface that tapers inward along tapered region  802  in a distal direction. The distal end of tapered region  802  may include a cross-sectional profile that matches that of a proximal end of grip  302 . Thus, foot  310  may transition smoothly from tapered region  802  to grip  302 . 
     In an assembled state, shaft  502  and foot  310  may be integral to grip  302 . For example, in an embodiment, shaft  502  may include a threaded base  804  near a proximal region. The threaded base  804  may be a male fastener that can engage a female threaded portion in grip  302 . Similarly, foot  310  may include a threaded portion extending distally from a distal end of tapered region  802 . The threaded portion may be a male fastener to mate with a corresponding female threaded portion in grip  302 . Alternatively, the threads of shaft  502  and foot  310  may be reversed with respect to grip  302 . For example, grip  302  may include male threaded portions that engage respective female threaded portions of shaft  502  or foot  310 . Accordingly, after threading shaft  502 , foot  310 , and grip  302  together, the parts may be securely fastened to make shaft  502 , foot  310 , and grip  302  integral to each other for all intents and purposes during use. 
     Referring to  FIG. 8B , an exploded view of a jump rope handle is shown in accordance with an embodiment. Alternative modes of fastening handle parts together may be used. That is, components such as shaft  502  and foot  310  may be fixed to grip  302  in numerous other manners. For example, shaft  502  may include a boss  806  having an outer diameter sized to produce a press fit with a counterbore or hole formed in grip  302 . Similarly, foot  310  may also include a boss sized to be press fit inside of a counterbore or hole formed in grip  302 . Thus, shaft  502 , foot  310 , and grip  302  may be pressed together during assembly to make the parts integral to each other for all intents and purposes during use. 
     Referring to  FIG. 8C , an exploded view of a jump rope handle is shown in accordance with an embodiment. In an embodiment, a handle  300  may include grip  302  integrally formed with shaft  502  and foot  310 . That is, grip  302 , shaft  502 , and foot  310  may be formed from a single piece of material. For example, a single piece of material, e.g., bar stock, may be machined to form a cylindrical shaft  502  region, a cylindrical grip region, and a tapered foot  310  region. Furthermore, shoulder  402  may be formed in the integral grip  302  to act as a transition region between shaft  502  and grip  302  and to maintain appropriate spacing between head  304  and grip  302 . That is, shoulder  402  may press against proximal bearing  504 , e.g., against an inner race  604  of the bearing, without pressing against head  304  or allowing head  304  to press against grip  302 . Accordingly, shoulder  402  may reduce friction between head  304  and grip  302 . In alternative embodiments, shoulder  402  may not be integrally formed with grip  302 , but may be a separately formed component. For example, shoulder  402  may be a collar concentrically located about shaft  502  or, as shown in  FIG. 8A , a shoulder region between threaded base  804  and shaft  502 . 
     Referring to  FIG. 9 , a perspective view of a distal portion of a jump rope handle is shown in accordance with an embodiment. As described above, a rope  100  may be passed through rope guide  406  between rope landing  315  and rope retainer slot  316  such that a rope end  902  is on an opposite side of rope landing  315  from a portion of rope that swings around the jumper. Rope may be secured within head  304  using various rope fasteners. For example, in a simple embodiment, a knot may be tied near rope end  902  such that the knot profile is too large to pass through rope guide  406  and therefore rope is secured within head  304 . In an embodiment, a collar  904  may be passed over rope end  902  and a set screw  906  may be threaded radially through collar  904  to pinch rope between an inner surface of collar  904  and a tip of set screw  906 . Thus, collar  904  may be fastened to rope near rope end  902 . Since collar  904  may have a profile too large to pass through rope guide  406 , collar  904  may therefore secure rope within head  304 . 
     In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.