Abstract: A frictional exercise device includes a shell body to be attached to a stationary object, for instance a door, a doorjamb or a floor, either directly or via a resistance band. A core cylinder in the shell body has an arcuate friction surface. A non-elastic strap winds partially around the core cylinder and hugs the friction surface. When said strap is pulled at one end, a frictional force between the friction surface and the strap opposes a movement of the strap across said friction surface. The magnitude of the frictional force is proportional to a resistive force applied at the opposite end. The arcuate friction surface is formed with a depression and adjoining elevations. A counterbrake projects towards the depression in the friction surface and deflects the strap towards the depression to define an undulating course of the strap along the friction surface and the counterbrake.

Abstract: A frictional exercise device includes a shell body to be attached to a stationary object, for instance a door, a doorjamb or a floor, either directly or via a resistance band. A core cylinder in the shell body has an arcuate friction surface. A non-elastic strap winds partially around the core cylinder and hugs the friction surface. When said strap is pulled at one end, a frictional force between the friction surface and the strap opposes a movement of the strap across said friction surface. The magnitude of the frictional force is proportional to a resistive force applied at the opposite end. The arcuate friction surface is formed with a depression and adjoining elevations. A counterbrake projects towards the depression in the friction surface and deflects the strap towards the depression to define an undulating course of the strap along the friction surface and the counterbrake.

Abstract: A frictional exercise device includes a shell body which can be attached to a substantially stationary object, for instance a door, a doorjamb or a floor, either directly or via a resistance band. A core cylinder in the shell body has an arcuate friction surface. A non-elastic strap winds partially around the core cylinder and hugs the friction surface. When said strap is pulled at one end and a resistive force is applied at the opposite end, a frictional force between the friction surface and the strap opposes a movement of the strap across said friction surface. The magnitude of the frictional force is proportional to the resistive force applied at the opposite end. The arcuate friction surface is formed with a depression and elevations adjoining the depression.