Brake arrangement for magnetic or electric ergometer

#The present invention relates to a brake arrangement for a magnetic or an electric ergometer according to the preamble of claim 1. Such an ergometer can be made e.g. of an ergometer bike.

#Different ergometers and particularly ergometer bikes have for years been the best way of measuring a person's condition and oxygen uptake. These arrangements usually comprise a frame, two pedals, a power transmission system, a rotating member and a brake arrangement. The brake arrangement included the ergometer bike preferably comprises a mechanical friction system or a magnetic or an electric eddy-current brake.

#Prior art brake arrangements are provided to affect the rotating member, e.g. a flywheel, which is driven by the power transmission system. The rotation of the flywheel is slowed down e.g. mechanically by a brake band placed against the outer circumference of the flywheel. The friction force between the flywheel and the brake band can be varied by tightening or loosening the brake band in respect of the outer circumference of the flywheel. In that case the braking force and the force needed to drive the power transmission system vary.

#In the following the invention will be described in greater detail with reference to the drawings, in which

#FIG. 1 illustrates schematically the most important parts of a prior art ergometer bike,

#FIG. 2 schematically illustrates the most important parts of a brake and calibration arrangement according to the present invention,

#An ergometer according to the present invention is described using an ergometer bike as an example. FIG. 1 schematically illustrates the essential parts of an ergometer bike known per se. The arrangement comprises a frame which is provided with two pedals 1. A rotating member 3, such as a flywheel, is made to rotate in respect of the frame by means of a power transmission system 2. The flywheel is provided with a brake arrangement 4 for influencing the flywheel. The rotation of the flywheel is slowed down mechanically with a brake band 5 arranged against the outer circumference 6 of the flywheel.

#The present ergometer, in comparison, comprises a brake arrangement, preferably provided with a magnetic or an electric eddy-current brake according to FIGS. 2 to 4. The eddy-current brake comprises a rotating member, i.e. a flywheel 3, which is at least partially made of or coated with a conductive material or magnetic means 7. The flywheel may also be coated with aluminum or copper or provided with permanent magnets similar to those used in magnetic ergometers. To affect the motions of the rotating member, at least a magnetic brake member 8 is positioned at an adjustable distance from the rotating member. By increasing or decreasing the distance between the magnetic brake member and the rotating member)the braking force and the force needed to drive the power transmission system can be varied.

#The magnetic brake member 8 has a known weight and is, according to the preferred embodiments of the present invention shown in FIGS. 2 to 4, attached to a pendulum 9 which also has a known weight. Such a pendulum can rotate freely in a vertical plane substantially parallel with the cross-sectional plane of the rotating member, i.e. the flywheel 3. The brake member 8 can thus be moved along the pendulum in a direction which substantially overlaps with the radius of the flywheel so that the brake member moves either closer to or further away from the flywheel along a shaft which substantially extends through a central shaft 10 onto which the rotating member is mounted. In the example the pendulum is concentrically pivoted on the flywheel so that the axis of rotation of the pendulum preferably coincides with the central shaft of the flywheel.