Exerciser device.

0001This invention relates to exerciser devices of the kind in which a shaft is rotated by a pair of pedal cranks or the like. The pedals may be arranged to be foot operated as in a bicycle, or hand rotated.

0002The shaft may be braked or it may be arranged to drive a braked element, and the brake may be adjustable so as to vary the work done and hence the amount of exercise obtained.

0003A problem with devices of this kind is that in converting near straight line motion ( of the user's arms or legs ) into rotary motion, the drive is most inefficient at two diametrically opposed points which it is convenient to call top dead centre (TDC) and bottom dead centre (BDC), although they are only vertically aligned in certain circumstances. If the brake is set to require considerable effort to turn the pedals, it may be difficult or even impossible to start the rotary motion if the pedals are left in the TDC and BDC positions, or the device may stall at such positions.

0004A relatively massive flywheel can minimise stalling, and various means are theoretically possible to ensure low resistance to turning until a minimum rotational speed is achieved, but all of these possibilities tend to be relatively expensive.

0005The object of the invention is to solve the problem in an inexpensive way.

0006According to the invention an exerciser device comprises a rotatable member which is braked, and which has at TDC and BDC positions ( as hereinbefore defined ) low friction areas for engagement by the brake.

0007The rotatable member may be a brake drum engaged by an externally contracting brake shoe, and the brake drum may be a metal casting with inset pads of plastics material. The plastics material is not necessarily one with an ultra low coefficient of friction such as polytetrafluorethylene, and it is sufficient if its coefficient of friction is merely substantially less than that of the remainder of the drum, as might be the case for example by using a light alloy die casting for the drum with nylon inserts for the low friction areas.

0008The brake shoe may have a lining of a conventional high friction material of the kind used for bicycle brakes or vehicle brakes, and it may be arranged to engage with the drum over a portion of its periphery, the brake pad having a generally rectangular shape. The length of the shoe and the corresponding dimensions of the low-friction material determine the effect obtained. Desirably there is a transition between the braking effect caused by engagement of the high friction brake pad with the medium friction metal of the drum and that caused by engagement of the same pad ( wholly ) with the low friction material, and vice versa, and equally desirably the full engagement between the low-friction material and the high friction material spans across the BDC and TDC positions.

0009A smooth transition can be achieved by shaping the friction surfaces so that during angular movement towards the BDC or TDC position a progressively greater proportion of the engaged areas involve the low friction material, and when the TDC or BDC position is passed, vice versa. This may be done with a circular pad of low-friction material which sweeps past the squared end of the brake shoe, but many other solutions are possible: for example a similar transitional effect can be obtained by using a brake pad which has shaped ends.

0010In a presently preferred embodiment of the invention, an exercise "bicycle" comprises a main frame which forms a stand supporting handle bars and a saddle. The frame journals a spindle carrying a pair of oppositely directed pedal cranks each terminating in a corresponding pedal possibly provided with a toe clip. The spindle is fixed to a brake drur so that the latter rotates with the spindle as the pedal cranks are turned, and the brake shoe is mounted at one end of a lever pivoted between its ends on the frame, with the end opposite to that carrying the shoe connected to an adjuster device for example by cable.

0011In a modification, the braked rotatable member may be a disc instead of a drum and in this event a caliper-type brake device can be used in conjunction with the disc.

0012To promote further understanding of the invention, one embodiment thereof will now be described by way of example only with reference to the accompanying drawing, the sole figure of which is a side view of part of a pedal exerciser.

0013As shown, the exerciser includes a frame having a seat tube 12 and rear legs 14 with a stablising crossbar 16. Although not shown, the frame will also include front legs with a stablising bar and handlebars as in a conventional cycle type exerciser. The frame journals a spindle 20 to which a pair of oppositely directed pedal cranks 22 are secured (only one crank 22 being shown in the drawing). The spindle 20 mounts a brake drum 24 and a flywheel 26 (shown in broken outline).

0014A link 28 is pivoted to the frame at 30 and carries at its lower end a pivoted brake block 32 for frictional engagement with the periphery 34 of the drum 24. The force with which the block 32 bears against the surface 34 is governed by a tensioning cable 36 engaging the link adjacent its upper end. The cable 36 is conveniently connected to an adjustable tensioning device which is mounted so as to be readily accessible to the user when seated.

0015The brake drum 24 is conveniently manufactured -as a casting with recesses for insertion of pads 38 of low friction material so that its periphery presents both low and higher frictional resistance areas to the block 32 as the drum rotates. The pads 38 are located at the previously mentioned TDC and BDC positions and they may be shaped as previously described so that the change in frictional resistance is progressive rather than abrupt.