Bicycle rollers have been in use since the early 1900's. A bicycle roller is a dynamometer for bicycles that is powered by the bicycle rider. A portable bicycle roller is traditionally comprised of one or more rotatable cylinders positioned so that the rear wheel of the bicycle rides on at least one cylinder, and one of the axles of the bicycle is fixed for stability. In the typical application, the front wheel is removed and the front fork of the bicycle is fixed to prevent the rider from tipping over.
In the prior art, the amount of power, or wattage, that the bicyclist is required to exert to ride at a given speed on a bicycle roller was determined by the amount of rolling resistance resulting from tire distress as the tire rolls over each of the cylinders plus the wattage required to drive any external devices which exert resistance on one or more of the cylinders. Rolling resistance is predominantly a function of the cylinder diameter, tire pressure, and bicyclist weight. Relying on these factors alone provides a linear relationship of resistance versus speed. Simple devices that add a predictable amount of resistance such as the magnetic eddy-current device of U.S. Pat. No. 6,857,992 (incorporated herein by reference) can be added externally to the cylinders, but these are undesirable since they provide a linear speed-to-resistance relationship.
Prior art bicycle rollers have a linear relationship of speed versus resistance. This solution is unsatisfactory; when beginning to pedal the bike from rest on rollers, low resistance is desired to allow the wheels to accelerate quickly enough to enable sufficient steering dynamics to keep the bicycle stable on the rollers. However, to obtain a meaningful training session, a high amount of resistance is desired when pedaling at a rate suitable to achieve cardiovascular exercise benefit.
To achieve both objectives it is desired to have a progressive resistance relationship with speed. In other words, a non-linear relationship between speed and resistance where the slope of resistance versus speed increases with increasing speed. This relationship is preferred because it more effectively simulates the non-linear effect of combined rolling resistance and wind resistance experienced when riding a bicycle in traditional fashion.
Eddy current devices use magnetism to generate electrical current in conductive materials when a magnetic field is placed in relative close proximity to the conductive material and relative motion of the magnet to the conductive material is present. The motion creates small electrical currents in the conductive material. The current creates a non-contacting friction between the two, along with generating heat in the conductive material. This heat must be dissipated in some fashion. Prior art resistance trainers utilize a large surface area on the roller(s) to dissipate the heat that is generated during use. For portable devices, parts must be made smaller to facilitate transportation and storage. This leads to a heat management issue, Prior art used a cylinder that contacted the rider's tire on the exterior and had the eddy current friction mechanism on the interior. With a large surface area, along with a good thermal conductor, it was possible to share the two uses with a single-walled cylinder. Reducing the size of the cylinder, while still maintaining the load capacity of the cylinder, it was necessary to add some additional form of thermal management. An improved eddy current device is needed.
The present disclosure describes an improved eddy current resistance device that fits into a smaller physical envelope, while still being able to provide the resistance of a much larger resistance device. By creating a cavity between the outer wall that carries the mechanical load of the rider's tire and the inner wall that generates the heat, it is possible to reduce overall size without compromising overall capacity. To dissipate the heat generated by the interior wall, fins directing air flow in the cavity between the outer and inner cylinder can be incorporated on the sides of the cylinder. The inner and outer cylinder can be connected through support members between the outside diameter of the inner cylinder and the inside diameter of the outer cylinder. These support members can be incorporated as part of an extrusion that makes the cylinders and support members one piece. The inner and outer cylinders can also be connected through the bearing support structure that allows the cylinders to rotate about the central axis. As such, a workable portable bicycle roller is desired.
Further, the progressive resistance device described herein is applicable to other stationary trainers, such as those sold for use with bicycles, handcycles and tricycles (see U.S. Pat. Nos. 7,011,607, 7,585,258, 6,964,633, and 6,042,517, each incorporated herein by reference). The progressive resistance device described herein is distinguishable from the magnetic resistance system for rollers (U.S. Pat. No. 6,857,992, incorporated herein by reference) in that the progressive resistance device automatically adjusts resistance level relative to speed, rather than being manually adjustable.
A preferred embodiment of this invention has been chosen wherein:
This disclosure describes an improved portable progressive resistance device 10 suitable for integration with a bicycle roller training device 12. The resistance device is shown with a driving mechanism, such as a bicycle 9 in
With the cylinder oriented such that rotation allows the magnet carrier to move against the torsional spring 35 (
Another benefit of the progressive resistance device described herein is that when a linear relationship between speed and resistance is desired, a rotational stop may be implemented on the pivotal magnet carrier so that pivotal angle is limited, preventing the magnet(s) 22 from getting closer to the inner cylinder 14 when the rotational direction of the cylinder is reversed. The inner cylinder 14 can rotate in an opposite direction described above—allowing the same progressive resistance device 10 to provide either linear or proportional training depending on the direction of rotation of the inner cylinder 14. With the progressive resistance device reversed, the result will be a linear relationship of speed and resistance. Therefore, the progressive resistance device 10 described herein is unique in that it allows the user to select progressive resistance or linear resistance, as desired. The ability to make this selection is important because users training on rollers on any given day may prefer progressive resistance in one session and linear resistance in another session. In practice, the progressive resistance device is removable from the roller frame 61 (
For most bicycle riders, the use of a trainer having a single progressive resistance device described herein may be adequate. However, because a bicycle roller can comprise more than one device 10, the use of one or two progressive resistance devices described herein may be used in the place of the roller's cylinders to achieve differing levels of resistance. In other applications, a second roller is simply an idler and provides little to no rolling resistance.
By adjusting the spring rate, spring preload, number of magnets 22, and other variables it is possible to adjust the progressive relationship between resistance and speed 50 to suit the needs of the designer or the user.
Because of the heat generated by the eddy currents in the inner cylinder 14 during use, the second wall 18 and annular space 20 (
An additional embodiment of this technology, to achieve a higher level of resistance on a single cylinder, is to include stationary magnets on the outer side of the progressive resistance device placed and oriented when the progressive resistance device is at rest. The poles of the moveable magnets inside the cylinder will oppose the stationary magnets outside the cylinder, thereby reducing the magnetic flux on the conductive cylinder wall and, when the progressive resistance device rotates during its normal operation, the moveable magnets inside the cylinder approach stationary magnets on the outside of the cylinder in such a way that the magnets are attracted by appropriate pole alignment; thereby increasing the magnetic flux on the conductive cylinder wall.
Applications of this technology are not limited to bicycle rollers and bicycle trainers, but are suitable in any application where a resistance mechanism is employed and it is desired that the resistance mechanism have a non-linear relationship to speed, such as a stationary bicycle, hand cycle ergometers, or any similar device. Because the progressive resistance device described herein is contained within a cylindrical drum and requires only that the cylinder be rotated relative to the axle, it can be driven by direct contact with a bicycle tire, or it can employ a chain and sprocket, a drive belt, or can be driven directly by any means to cause rotation of a cylinder on an axle.
A portable roller-type stationary bicycle trainer 12 includes a cycle attachment 139 shown in
A roller frame 61 includes oppositely located sides 60 that support the axles 30 of the cylinders. The sides 60 have an upstanding portion 46 and a support portion 48 (
The arm 64 is pivotally connected to the front frame member 76 with a bolt 94 that extends through the tubes 80 that straddle the notch 92. The ends of the tubes 80 adjacent to the notch 92 receive plugs 124. The opposite ends of the tubes 80 are open. Intermediate to the ends of the tubes 80 are a pair of transverse holes 102. The transverse holes 102 have a first aperture 104 that is formed through wall 82 of the tube diagonally opposite where the web 88 joins each tube 80. The transverse hole has a perimeter that is circular in cross section. Each transverse hole 102 continues into its corresponding tube 80 to the inner surface 84 opposite the first aperture 104 to form a bottom portion of the transverse hole 102. The bottom portion of the hole 102 extends beyond the inner surface 84 but not through to the flat side 90 of the front frame. Where the web 88 joins each tube 80, there is optionally a gusset that is integral to the web 88 and corresponding tube 80. The gusset adds thickness where the web 88 joins each tube 80. The gusset is useful to provide additional material near the bottom portion of each transverse hole 102. The bottom portion is a cylindrical depression within the wall 82 having a flat circular bottom and a cylindrical perimeter. Within the flat circular bottom is a centrally located tapped hole 134. All shown in best detail on exploded
Legs 120 are made from round tubular aluminum but can be made from other structural materials. One end of the leg 120 receives a plug 122 that provides a non-slip, non-marring end to the legs 120 that will rest on a floor. The plug 122 is shown as a rounded end rubber plug. The opposite end of the legs 120 are cut squarely to from a second end. From the center, near the second end of each leg 120 is an attaching end, shown as a threaded stud 128 extending therefrom. The threaded stud 128 is designed to be screwed into a threaded hole 134. When this is done, the transverse hole 102 sets an oblique angle between the legs 120 and the tubes 80 to which the legs 120 extend from. The second end fits within the bottom portion of its corresponding transverse hole 102 and is supported laterally by the perimeter in the inner surface near the bottom portion. The transverse hole 102 supports the leg 120 at a distance spaced from the bottom portion to provide a rigidly supported connection between the leg 120 and the front frame member 76.
When the legs 120 are not in the transverse holes 102, they are stored in the tubes 80. The inner surface 84 forms a cavity slightly larger than the outer diameter of the leg 120. The leg 120 is inserted into the tube 80. Each tube 80 includes a threaded hole 117 also referred to as a receiver that receives the stud 128 so that the leg 120 may securely held within a tube 80 when threaded stud 128 is screwed into a corresponding threaded hole 117.
The groove 78 is capable of receiving the arm 64 within it when the arm 64 is folded onto the front frame member 76. When the arm 64 is folded into the groove 78, it rests within the groove 78 and in between the two tubes 80. The arm 64 may be adjusted so that the length of the arm 64 locates the open ends of the tubes 80 adjacent to the pivot where the arm 64 is joined to the roller frame 61. From this position, the front frame member 76 may be folded to the sides of the roller frame 61 opposite where the cylinders are mounted. Because the cylinders have their outermost surface spaced from the bottom of the roller frame, the flat portion of the front frame member 76 may rest substantially aligned with the bottom of the roller frame when the front frame member 76 is folded in this position with respect to the roller frame 61. A quick release bolt 140 (
When the progressive resistance device is used, the driven wheel of a bicycle is placed on the two rear cylinders and the front wheel of a bicycle may be removed and the front axle or fork is mounted using the bolt 140 to the front frame 76 that supports the front and stabilizes the bicycle frame. In this application, not requiring the skill of the user to balance, the driven wheel of a bicycle is placed between the two roller cylinders and aligned in such a way that the tire of the bicycle, tricycle, or handcycle remains in contact with the roller cylinders during use. In a manner as is known, the user pedals the bicycle, tricycle or handcycle so as to rotate the driven wheel which in turn rotates the cylinder or cylinders supporting the driven wheel.
As is depicted in
In order to make the folded position of the training device 12 as compact as possible, the front frame 76 partially fits inside the channel that is created between the support portions 48 of the roller frame 61. The training device 12 can be fixed in the folded position by locking the bolt 140 in the notches 142. As shown in the folded and stored position in
It is understood that while certain aspects of the disclosed subject matter have been shown and described, the disclosed subject matter is not limited thereto and encompasses various other embodiments and aspects. No specific limitation with respect to the specific embodiments disclosed herein is intended or should be inferred. Modifications may be made to the disclosed subject matter as set forth in the following claims.
This application claims the benefit of U.S. Provisional Application No. 61/935,583, filed Feb. 4, 2014, the disclosures of which are hereby incorporated by reference.
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