Patent Publication Number: US-2018036574-A1

Title: Stationary Wind Trainer

Description:
TECHNICAL FIELD 
     The present invention relates to a stationary trainer for use as a training or an exercising machine when the stationary trainer replaces the rear wheel of a bicycle, and in particular to a stationary trainer including a fan, commonly referred to as a wind trainer. 
     BACKGROUND ART 
     Stationary trainers are devices that are used to convert a bicycle so that it can be ridden without movement of the bicycle/trainer. Stationary trainers are commonly used with a bicycle to provide a convenient form of training/exercise for a user, usually indoors. 
     A trainer typically consists of a frame configured to engage the rear axle of the bicycle and to lift the rear wheel of the bicycle off the ground. A roller is commonly pressed against the tyre of the rear wheel, so that the roller rotates as the user operates the pedals of the bicycle. The roller is further coupled to some form of resistance device, often adjustable, that can enable a user to vary the amount of resistance felt when pedalling, and hence the intensity of the exercise. One simple resistance mechanism is to couple a fan to the roller, the fan designed to create resistance as it rotates in the air. A stationary trainer that uses a fan to provide the resistance is commonly referred to as a wind trainer. A wind trainer typically has a small fan which is coupled to a flyweight to provide greater resistance. Other common types of stationary trainers use a magnetic flywheel to create resistance (so called “mag trainers”) while others use a flywheel inside a cylinder filled with fluid (so called “fluid trainers”). 
     While such trainers are typically satisfactory for use as exercise machines, problems can arise when used by high performance athletes who can produce large forces and accelerations on the rollers. This can lead to slippage of the tyre against the roller, thus reducing the effectiveness of the trainer as a training device, as well as general wear and tear which can increase maintenance costs. 
     Problems can also arise when such trainers are used for rehabilitative exercise as a relatively high force may be required initially to spin the roller. Exerting such a high initial force can be detrimental to rehabilitation of the user. 
     Furthermore, some forms of resistance mechanisms may be limited under these low pedal speed conditions—for example, magnetic resistance devices can tend to “grip” the tyre at the top and bottom of each pedal stroke making it difficult for the user to keep up an even pedalling motion—as well as failing to recreate the sense of cycling on a road/track, which is very important to high performance cyclists using the devices. 
     Slippage can be addressed by increasing the force holding the roller against the tyre. However, this can lead to a similar problem to that discussed above for mag trainers, namely the resistive force due to the roller can become so great that it slows the tyre significantly (and in extreme cases may stop the tyre) at the top and bottom of each pedal stroke. 
     Wind trainers with a suitable fan size can provide a level of resistance that varies with speed and pedal pressure in a way that does provide a realistic representation of how the cyclist would feel if riding on a surface (road/track etc). Ideally, high performance athletes and cyclists would want to combine the advantages of a wind trainer without the problems associated with use of a roller pressed against the rear tyre of the bicycle. 
     This has led to the development of stationary trainers in which a large fan is driven directly by a chain see, for example, the BT Advanced Training System™ on biketechnologies.com. These trainers, which are typically called an “Erg” or “Ergometer” trainer, are configured for use with a bicycle with the rear wheel removed. These advanced stationary trainers incorporate a large fan which is driven directly by a chain drive coupled to a gear cog on a drive hub that connects with the rear dropouts of a bicycle (i.e. in place of the rear wheel axle). The drive hub and fan are supported on a frame constructed from tubular sections, the frame connected to two tubular stabilisers that extend out each side of the trainer to provide lateral stability. The fan is typically covered by a plastic shroud for safety reasons. 
     In use the rear dropouts of a bicycle are connected to the drive hub of the wind trainer, so that the frame of the wind trainer supports the rear end of the bicycle and the rider. The bicycle chain is connected to a gear cog on the drive hub of the wind trainer, so that movement of the pedals on the bicycle drives the drive hub of the wind trainer which, in turn, drives the fan hub and hence the fan. 
     While the chain drive and large fan may overcome some of the problems associated with traditional wind trainers, a wind trainer of this type can be relatively large. In part this can be due to the size of the tubular frame required to provide the necessary strength to support the bicycle and rider, and to control the amount of flexing of the trainer during use. As the size of the frame increases so too does the weight. 
     Size and weight can be significant factors in selecting a wind trainer, particularly when there is a requirement to transport it from one site to another. This can occur, for example, when a cyclist requires a stationary trainer when attending an event away from the cyclist&#39;s normal base. In such instances there can be limited space available in a vehicle for the stationary trainer along with all the other equipment that must be carried. The size and weight of a stationary trainer are also very important considerations where the trainer is to be transported by airplane NZ Patent No. 287722 (the entire contents of which are included here for reference), called the Revbox™, discloses a stationary wind trainer that is relatively compact and light, thus overcoming some of the disadvantages of earlier trainers. 
     However, a further disadvantage with all prior art advanced wind trainers, which can be significant, is the amount of noise generated by t wind trainers when used at high intensity (high revolutions). This noise can easily be such as the rider requires some kind of ear protection (earplugs, sound reducing headphones, music player etc.) in order to ride the bicycle with the wind trainer. Further the noise can affect other people in the vicinity of the wind trainer—e.g. in the same house, flat, block of flats, gymnasium, fitness centre and so on. At the very least the noise generated can be generally inconvenient to the rider and any other people in the vicinity of the wind trainer when in use. 
     Yet another disadvantage with high end wind trainers is that the power required to drive the fan can be affected by air flow into and around the region where the fan is operating. Indeed if insufficient air flows into the region around the fan the resistance provided by the fan can be significantly limited. As an example, the shroud which encloses the side of the fan compartment of the BT Advanced Training System™ for safety reduces the flow of air into the region in which the fan operates, thus limiting the high end performance of the fan. 
     It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice. 
     All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country. 
     Throughout this specification, the word “comprise”, or variations thereof such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. 
     Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. 
     DISCLOSURE OF THE INVENTION 
     It is an object of the present invention to provide a high efficiency, compact stationary wind trainer which is both quieter and less limited in performance than prior art machines. Noise reduction may be achieved by ensuring there is adequate space around the fan blades for the air that has been rapidly accelerated to dissipate some of its speed/energy before hitting any obstacle, such as a side panel of the frame of the trainer. The upper end efficiency of the fan, enabling the wind trainer to continue to generate appropriate resistance at high operating speeds, may be achieved by ensuring ample air flow into and out of the region around the fan. This may be achieved not only be ensuring adequate space between the fan and the sides/frame of the wind trainer, but also by allowing as much flow as possible through and/or around the sides or frame of the wind trainer. 
     According to one aspect of the present invention there is provided a stationary trainer for use with a bicycle with the rear wheel removed, the stationary trainer including: 
     a fan assembly including a fan blade attached to a fan hub configured to rotate about a fan hub axle;
 
a drive assembly including a drive hub having at least one gear cog configured to connect with a chain of the bicycle for providing power to the stationary trainer, and a chain ring, the drive hub configured to rotate about a drive hub axle, wherein the drive hub axle is configured to engage with the rear dropouts of the bicycle;
 
a chain drive including a chain connecting the chain ring on the drive hub to a cog on the fan hub;
 
a first side panel located on a first side of the fan;
 
a second side panel located on a second side of the fan opposite the first side of the fan; and
 
one or more bracing elements connecting the first side panel to the second side panel, wherein a distance between an edge of the fan blade and either the first side panel or the second side panel is in the range from 4 mm to 70 mm.
 
     In a preferred embodiment the distance between the edge of the fan blade and either the first side panel or the second side panel is in the range from 10 mm to 20 mm. 
     The applicant has found that the amount of noise generated by the wind trainer, in use, is dependent on the spacing between an edge of the fan blade and the neighbouring side panel. In particular with the spacing around 15 mm there is a significant reduction in noise from the fan blade(s). This may allow the wind trainer to be operated without causing significant noise problems for the rider and other people in the vicinity, thus making the wind trainer of the present invention more user-friendly. 
     Preferably the fan blades are formed from a first sheet material. 
     Preferably the first sheet material is aluminium sheet. However, in some embodiments other sheet material, including stainless steel, may be used, particularly to provide different inertial effects. 
     The applicants have found that reducing the weight of the fan may provide some important implications for training specificity. In particular, the lower inertia of an aluminium fan may create a perfect training environment for working on specific aspects of a rider&#39;s pedalling technique and strength, such as replicating the effect of riding up a gradient. 
     In preferred embodiments a surface of the fan blade includes a dampening material. 
     A dampening material may be coated onto a surface of each fan blade to reduce vibration and flexure of the fan blade. 
     The reduction in weight also aids the overall requirement of keeping the weight of the trainer as low as possible, thus aiding moving and transporting the trainer. 
     In a preferred embodiment the fan assembly includes a plurality of blades oriented symmetrically about the axis of rotation. 
     The applicants have found that use of a symmetrical fan may reduce vibration that can occur particularly at very high revolutions. Although an asymmetric fan design may be designed so that little or no vibrations occur at high revolutions, it was found that this generally involved a fan having a higher weight and cost than a symmetric fan. 
     In a preferred embodiment the fan includes 7 to 10 fan blades. 
     The applicant has found that using 6 or less fan blades leads to increased vibration of the wind trainer, while using more than 10 fan blades may create too much resistance to the rider on the wind trainer. 
     In a preferred embodiment the fan hub includes a flange located towards one end of the fan hub, the flange configured to attach to the fan, and a threaded portion located towards the opposite end of the hub. 
     In a preferred embodiment the fan hub includes a pair of flanges, one on each end of the hub, each flange configured to attach to a side of the fan. Attaching the fan to a flange on each end of the hub may provide a secure and symmetric arrangement which may reduce any tendency of the fan to vibrate or wobble about the hub axis when in use. 
     In a preferred embodiment the fan hub includes a freewheel cog engaged with the fan hub. 
     Preferably the freewheel cog is a BMX freewheel cog. A BMX freewheel cog has the freewheel mechanism in the cog rather than in the hub. The inclusion of a freewheel cog enables a rider to stop pedalling if necessary. Furthermore, the combination of a fan hub and a BMX freewheel cog may reduce vibration and instability of the spinning fan as any wear in the freewheeling cog will not affect the alignment of the fan (as it is connected to the flanges of the fan hub independently of the freewheel cog). The BMX cog may be screwed into the threaded end of the fan hub. 
     In a preferred embodiment the fan assembly and the drive assembly are supported by the first side panel and the second side panel. 
     A stationary trainer according to the present invention may be made more compact than prior art trainers by using the side panels and bracing element to carry out the function of the typically tubular frames of conventional trainers. The side panels of the present invention may be located close to the various components of the wind trainer, thus providing a device whose overall dimensions are determined more by the dimensions of the fan than by the size of the tubular frame supporting the fan and drive hub. 
     Reference throughout this specification to a side panel configured to support a fan or drive assembly of a stationary trainer should be understood to mean that the panel has sufficient structural integrity and rigidity to support the fan hub axle and the drive hub axle, and associated loads, during use of the stationary trainer for training or exercising by a rider on a bicycle attached to the stationary trainer. 
     In a preferred embodiment the first side panel includes a second sheet material. 
     In a preferred embodiment the second side panel includes a third sheet material. 
     A side panel formed from a sheet material may provide greater structural integrity and rigidity than a panel made up from a number of components joined together. Furthermore, a side panel formed from a sheet material may be formed without the need for fasteners, welds or other means of joining pieces together, thus saving on manufacturing and component cost. 
     In a preferred embodiment the second and third sheet materials have a thickness greater than 5 mm. 
     Preferably the side panels are formed from sheet materials having a thickness in the range 9 mm to 10 mm. 
     The applicants have found that a sheet material of thickness around 9 mm—10 mm may have the required structural integrity to withstand the forces applied to the side panels during use of the stationary trainer. Generally the stability of the side panels increases as the thickness of the sheet material increases—however the increased thickness of the sheet material increases the size and weight of the stationary trainer. The preferred range of thickness may provide a suitable compromise (for most sheet materials) between providing the required rigidity of the panels and limiting the size and weight of the trainer. 
     In a preferred embodiment the second and third sheet materials include an acrylic panel. 
     Reference to acrylic panel throughout this specification should be understood to mean any of the range of panels formed from acrylic material (i.e., any chemical compounds that contain the acryl group derived from acrylic acid). In particular it includes a panel formed from Poly(methyl methacrylate) (PMMA). Such panels are readily available commercially, including under such names as Plexiglas™, Lucite™ and Perspex™. 
     An acrylic panel is preferred as, at suitable thickness, it may be sufficiently rigid to support the applied load of a cycle and rider, while being relatively light-weight, making it ideal for lifting, moving and transportation as required. In general an acrylic panel is relatively inexpensive, light, readily available and readily machined material which also has good load bearing qualities, particularly in compression. Preferably a side panel may be formed from a single sheet of acrylic by cutting it to the required shape and including cut-outs for mounting the drive hub and fan hub axles. An acrylic panel may be cut into shape using laser cutting, for example. 
     Reference will be made throughout this specification to a side panel formed from acrylic material. However, those skilled in the art will readily appreciate that numerous other materials may be used to construct panels having the required structural integrity, stiffness and rigidity to provide an adequate framework for a stationary trainer, and that reference to a side panel as formed from acrylic only should not be seen as limiting. 
     In other preferred embodiments the sheet material is a high density plastics material. 
     Forming a side panel from high density plastics material, such as high-density polyethylene (HDPE) may be relatively cost effective and provide a strong, light structure for the trainer. As is well known, a panel may be formed relatively easily using plastics materials and generally does not require any further surface preparation, such as painting, which may reduce costs. 
     Alternatively the sheet material may be a metal plate, such as plate steel or aluminium, or may be medium density fibreboard (MDF) having a density in the range 600 kg/cm 3 to 800 kg/cm 3 . 
     In a preferred embodiment the first side panel includes one or more apertures. 
     In a preferred embodiment the second side panel includes one or more apertures. 
     Including one or more apertures in the body of the side panel may alter the resistance (drag) experienced by the fan during rotation between the side panels. The number, shape and configuration of the aperture(s) may be chosen to tune the drag forces so that the rider needs to use an appropriate power to rotate the fan at any given speed. (In other words, the drag characteristics may be chosen to provide the desired response to the rider). An aperture may be readily formed in the acrylic panel using laser cutting. 
     According to another aspect of the present invention there is provided a wind trainer substantially as described above, wherein the first side panel includes one or more apertures which are spanned by a mesh. 
     In a preferred embodiment an area spanned by the mesh is in the range of 60% to 90% of an area of the first panel. 
     According to another aspect of the present invention there is provided a wind trainer substantially as described above, wherein the second side panel includes one or more apertures which are spanned by a mesh. 
     In a preferred embodiment an area spanned by the mesh is in the range of 60% to 90% of an area of the second panel. 
     In a preferred embodiment the area covered by the mesh includes 70% to 95% voids. 
     In a particularly preferred embodiment area covered by the mesh is around 90% of the area of the first side panel and/or the second side panel. 
     When 60% to 90%, and particularly around 90%, of the area of the side panel is spanned by mesh having between 70% and 90%, and preferably around 90%, of voids, air can be drawn into the region inside the panels where the fan is operating. This may reduce a limitation of some prior art machines where the panels are either solid or include a safety shroud which can reduce (or place a lower upper limit on) the amount of resistance provided by the fan, while still providing a safety barrier around the fan. 
     In a preferred embodiment the aperture in the side panel includes a cavity around the perimeter of the aperture configured to accept and retain an edge of the mesh. 
     The amount of mesh/area of the apertures is obviously limited by the need to ensure the panel is still sufficiently rigid so as to support the rider, fan assembly etc. and to limit flexing of the panel when the wind trainer is in use. 
     In a preferred embodiment the first side panel and the second side panel are held in a fixed relationship by one or more bracing elements which connect the first side panel to the second side panel. The bracing element(s) are configured with the first side panel and the second side panel to provide a rigid framework, and particularly to limit movement of the side panels when the stationary trainer is in use. 
     Using a framework provided by the two side panels and associated bracing element(s) to support both the drive assembly and the fan assembly may provide a more rigid connection between the drive hub and the fan hub than that provided by conventional frame trainers of the prior art. This may be particularly important in reducing flexure of the trainer during high intensity training and in providing overall stability to the stationary trainer. 
     In a preferred embodiment the one or more bracing elements include a fourth sheet material attached to the first side panel and to the second side panel. 
     In a preferred embodiment the fourth sheet material is a second mesh. 
     Preferably the second mesh is the same as that used in the apertures in the side panels. Preferably the side panel includes a cavity around the perimeter of the aperture configured to accept and retain an edge of the second mesh. 
     In a preferred embodiment a distance between the second mesh and an edge of the fan blade is in the range from 4 mm to 70 mm. 
     In a preferred embodiment the distance between the second mesh and an edge of the fan blade is in the range from 40 mm to 60 mm. 
     Again, this arrangement is to provide sufficient space around all edges of the fan blade in order to reduce the noise made by the rotating blade. 
     In preferred embodiments the one or more bracing elements incudes a spacer. 
     Preferably the spacer includes a solid cylinder having an internally threaded section at each end, the internally threaded section being configured to accept a threaded bolt. 
     In a preferred embodiment, a plurality of spacers are placed around the perimeters of the first side panel and the second side panels and fixed in place by inserting bolts through each panel and into the ends of the spacer. 
     A plurality of such spacers may be located around the outer portion of the panels (i.e. sufficiently far from the fan hub axle to provide clearance for the fan) to hold the first and second side panels in fixed relationship with one another while at the same time providing the required clearance around the fan blade. 
     In a preferred embodiment the first side panel is located outside the chain drive and the fan. Locating the first side panel in this fashion improves the overall balance of the wind trainer when in use. 
     In a preferred embodiment the drive hub includes a chain ring located inside and in the vicinity of the first side panel. An advantage of this arrangement is that it may provide a more compact form than can be achieved by mounting the chain ring on a separate drive hub, or by mounting it on the opposite side panel to the gear cogs. 
     In a preferred embodiment the chain ring is an off-set chain ring. 
     Reference to an off-set chain ring throughout this specification should be understood to refer to a chain ring in which the ring of teeth around the perimeter of the chain ring that engage with the chain is off-set from the plane of the main body of the chain ring. In particular the teeth are off-set towards the first side panel. 
     An advantage of using an off-set chain ring is that the main body of the chain ring may be arranged closer to the one or more gear cogs than would be the case with a conventional (planar) chain ring. As a consequence the main body of the off-set chain ring may be sufficiently close to the inside cog to prevent the chain from falling off the gear cog. This may provide a safeguard against damage to the derailleur or the bicycle should the rider change gear too far. 
     In other embodiments the drive hub may include an adaptor plate mounted adjacent the chain ring. This arrangement may be used with a conventional (planar) chain ring, where the adaptor plate is mounted between the chain ring and the one or more gear cogs. The adaptor plate may provide a similar safeguard to that provided by use of an off-set chain ring, although generally the addition of an adaptor plate may lead to the addition of extra weight to the stationary trainer (e.g. the weight of the plate plus any connection to the chain ring/drive hub), which is undesirable. 
     In a preferred embodiment the stationary trainer includes a stabiliser extending substantially orthogonally from a plane of the first side panel. A stabiliser may be in the form of a plate and/or one or more legs that extend out from the side panels, the function of the stabiliser being to provide stability to the stationary trainer and additional resistance to any sideways force applied to the stationary trainer. 
     In a preferred embodiment the stabiliser includes a quick release mechanism. 
     Reference to a quick release mechanism should be understood to mean a release mechanism that does not require the use of a tool—i.e., is hand operated. Use of a quick release mechanism has the advantage of saving time and effort when assembling or disassembling the trainer, as may occur following or prior to storage/transport of the trainer. 
     Preferably the quick release mechanism is a quick release cam lever. 
     In a preferred embodiment the stationary wind trainer includes a foot connected to the first side panel and the second side panel in the vicinity of the drive hub. 
     In some embodiments the separation between the first side panel and the stabiliser may be adjustable. An advantage of this is that the stationary trainer of the present invention may be used with bicycles of different wheel and tyre diameters, the separation between the side panel and the stabiliser being adjusted to keep the axle line of the bike horizontal. 
     According to another aspect of the invention there is provided a kitset of parts for a stationary trainer for use with a bicycle having the rear wheel removed, the kitset including: 
     a fan hub having a fan hub axle;
 
a fan configured to attached to the fan hub;
 
a drive hub including at least one gear cog configured to connect with a chain of the bicycle for providing power to the stationary trainer;
 
a drive hub axle configured to connect to the rear fork dropouts of a bicycle;
 
a chain drive configured to connect the drive hub to the fan hub;
 
a first side panel;
 
a second side panel; and
 
one or more bracing elements,
 
wherein, on assembly, a distance between an edge of the fan blade and either the first side panel or the second side panel is in the range from 4 mm to 70 mm
 
     In a preferred embodiment, on assembly, the fan assembly and the drive assembly are supported by the first side panel and the second side panel. 
     In a preferred embodiment the first side panel, the second side panel and the one or more bracing elements are configured to provide a framework to support the drive hub axle. 
     In a preferred embodiment the kitset includes a set of instructions for assembling the stationary trainer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which: 
         FIG. 1  shows a schematic isometric view of a stationary trainer for a bicycle according to one embodiment of the present invention; 
         FIG. 2  shows another schematic isometric view of the stationary trainer of  FIG. 1 ; 
         FIG. 3  shows a schematic plan view of the stationary trainer of  FIG. 1 ; 
         FIG. 4  shows a schematic side view of the stationary trainer shown in  FIG. 1 ; and 
         FIG. 5  shows a schematic of a fan assembly according to one embodiment of the present invention. 
     
    
    
     BEST MODES FOR CARRYING OUT THE INVENTION 
     A stationary trainer according to one embodiment of the present invention is generally indicated by arrow  1  in  FIGS. 1-5 . The stationary trainer  1  includes a fan assembly, including a fan  2 , a fan hub  3  and a fan hub axle  4 , and a drive assembly including a drive hub  5 , gear cog  6 , chain ring  7  and drive hub axle  8 . The fan assembly and the drive assembly are mounted to and supported by a first side panel  9  and a second side panel  10 , with the side panels located on either side of the fan with an internal separation of 85 mm. 
     The fan, which is formed from sheet aluminium, has  9  vanes  11 , as shown most clearly in  FIG. 5 . Each vane  11  has a width of 59 mm and a length from the centre of the fan hub axle  4  to the tip of the vane of about 295 mm. The spacing between an edge of the vane  11  and the inside of each side panel is 15.5 mm. This distance is considered to be a good trade off between noise reduction and keeping the width of the wind trainer compact. 
     The fan hub  3 , which is shown most clearly in  FIG. 3 , includes a BMX freewheel cog  12  threaded onto the hub. The fan hub is attached to, and supported by, the side panels  9  and  10 . 
     The drive assembly, which is most clearly seen in  FIG. 2 , includes a drive hub  5  having a set of cassette gears  6  configured to attach to a chain on a bicycle (not shown). The drive hub rotates about a drive hub axle  8  which is configured to engage with the rear fork dropouts of a bicycle. In this manner a bicycle can be attached to the stationary trainer by engaging the rear fork dropouts with the drive hub axle (in the usual manner, the drive hub axle taking the place of the rear axle of the bicycle) using quick release cam levers (not shown in the figures) to lock the drive assembly  5  to the dropouts of the bicycle, and connecting the chain of the bicycle to the cassette gears. A rider may then pedal the bicycle to power the drive assembly of the stationary trainer, including shifting gears in the normal fashion. 
     The drive assembly includes a chain ring  7 . The toothed perimeter  13  of the chain ring is off-set towards the first panel  9 . This arrangement allows the chain (not shown) connecting the chain ring  7  to the BMX freewheel cog  12  to be located close inside the first panel  9 , which may reduce the width of the stationary trainer. 
     The drive hub  5  and drive hub axle  7  are mounted to the side panels  9  and  10 . 
     The first side panel  9  and the second side panel  10  are each formed from a single acrylic sheet (PMMA) of 12 mm thickness. The side panels ( 9  and  10 ) in this embodiment are predominantly in the form of circular discs of diameter around 630 mm, apart from an extension on the edge of the first side panel  9  is used to mount the drive hub axle  7  and to protect the chain. Six apertures  14  are laser cut into each side panel. The apertures allow air to move through the apertures and onto the fan  2  as it rotates between the first side panel  9  and the second side panel  10 . The apertures include a cavity (not shown) in the side panel configured to accept and retain a mesh  15  which covers the aperture, as shown in  FIG. 4 . 
     As can be seen in  FIGS. 1- 4 , the fan assembly  3  and the drive assembly  5  are both connected to and supported by the first side panel  9  and the second side panel  10   
     The side panels,  9  and  10 , are held in a fixed relationship by a plurality of bearing elements in the form of spacers  16 . The spacers are in the form of a solid cylinder which has an internally threaded cavity at each end, the cylinder having a length of 85 mm, being equal to the desired separation of the opposing surfaces of the side panels. A bolt is inserted through a hole near the circumference of one of the side panels and screwed into the threaded end section of the spacer. A plurality of such spacers are fitted around the circumference of the side panels. 
     Apart from the spacers the space between the circumferences of the two side panels is open. This open space is covered by a mesh of the same type as used to cover the apertures in the sides of the two side panels. 
     The stationary trainer  1  includes stabilisers in the form of cylindrical tubes  17 ,  18  that extend sideways from each side of the stationary trainer as shown in  FIGS. 1-4 . (The stabilisers are not shown in  FIG. 6 ). The stabilisers are connected to the first and second panels ( 9  and  10 ) by quick release hand-operated cam levers ( 19  and  20  respectively). 
     The stationary wind trainer  1  is further supported by a foot in the form of a triangular steel member  21  which is attached to the first side panel  9  and the second side panel  10  in the vicinity of the drive hub  5 . The rear end of the side panels are supported by adjustable feet  22  and  23 . The adjustable feet are used to adjust the level of the panels. 
     Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.