EP0951418A2

EP0951418A2 - Free wheel pedal crank and bicycle or medical exercise devices equipped therewith

Info

Publication number: EP0951418A2
Application number: EP98904014A
Authority: EP
Inventors: Steffen Heintz
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-01-08
Filing date: 1998-01-08
Publication date: 1999-10-27
Also published as: AU6204898A; DE19880014D2; WO1998030434A3; DE19800360A1; WO1998030434A2

Abstract

The invention relates to a free-wheel pedal crank, in particular for bicycles and medical exercise devices, with a crank arm, which has an actuating element in the form of a pedal or similar in the region of its first end, and which, in the region of its second end, can be fastened via a free-wheel to a bottom bracket ball bearing shaft in such a way that, upon rotation of the crank in a first direction, a turning moment is transferred to the bottom bracket ball bearing shaft, and in counter rotational direction, torque decoupling ensues. The invention is characterized in that it has at least one weight body which is fitted at the second end of the crank arm, and which is formed, dimensioned and positioned in such a way that, upon releasing the actuating element, the crank arm automatically swings into a rest position, whereby the crank arm runs substantially upwards from the bottom bracket ball bearing, in relation to the direction of the weight force. The invention further relates to a bicycle or medical exercise device equipped therewith.

Description

Freewheel crank and equipped bike or medical

Exercise device

The invention relates to a freewheel pedal crank according to the preamble of patent claim 1.

The invention further relates to a bicycle or a medical exercise device according to the preamble of patent claim 12.

Bicycles usually have a free wheel in the rear axle hub. This makes it possible to decouple the pedal cranks or the pedals from the rotating hub in one direction of rotation.

From Austrian patent specification AT 178 803 it is also known to provide both pedal cranks of a bicycle with a freewheel in the manner of a spring-loaded pawl, which is intended to make it possible to drive the bicycle in addition to the conventional circular drive in the manner of a pendulum drive.

A so-called multifunctional bicycle is known from the magazine Radmarkt No. 1 1/1992, p. 69, in which both pedal cranks are also freewheeled from the rear axle hub and from each other Can be decoupled, so that the pedals can be rotated completely independently of one another or can be held in the rest position.

Although these known bicycles with free-wheeling cranks are suitable for use by users with permanent or temporary disabilities, in particular with restricted mobility, for example after knee or hip operations, they have the significant disadvantage that after a pedal is pressed into the lowest position this must be actively moved up again. For this purpose, the known bicycles have hooks, brackets or straps on the pedals into which the respective user has to slip with his foot, so that the pedal is taken along when the foot is lifted. Especially for disabled or motion-restricted users, this is not without danger when operating a bicycle of this type, in particular in the event of a fall, and easily leads to a feeling of insecurity.

Starting from this prior art, it is the object of the present invention to create a freewheeling crank which does not have these disadvantages.

This object is achieved by a freewheel pedal crank according to the teaching of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

The freewheel pedal crank according to the invention, in particular for bicycles and medical exercise equipment, has a crank arm which is provided in the region of its first end with an actuating element in the form of a pedal or the like. According to the invention, the term “pedal” is not restricted to an element that is actuated with the feet; rather, actuation elements that are actuated with other parts of the body, in particular with the hands, are also to be included Equipment or fitness equipment that works with any Body part are operated as long as there is a rotary or crank movement.

In the area of its second end, the crank arm can be fastened in a manner known per se via a freewheel to a bottom bracket shaft in such a way that when the crank is turned in a first direction, torque can be transmitted to the bottom bracket shaft and torque decoupling takes place in the opposite direction.

According to the invention, the freewheel crank has at least one weight body arranged at the second end of the crank arm, which is shaped, dimensioned and positioned in such a way that, when the actuating element is relieved, the crank arm is automatically pivoted into a rest position, in which the crank arm essentially moves upward from the bottom bracket, related to the direction of the weight.

In other words, this means that after actuating the pedal and by lifting, for example, the actuating foot and the associated relief of the pedal due to the weight of the weight, the pedal is automatically swung up into an uppermost rest position without an active intervention by one Users need, in particular without a connection between the foot and the pedal caused by brackets, straps or hooks.

According to a preferred embodiment of the invention, the weight body is arranged substantially diametrically opposite the actuating element with respect to the bottom bracket axis. This means in particular that a simple design of a freewheeling pedal curve according to the invention can be achieved in that the moment from the mass of the weight body x the distance of the center of mass of the weight body from the bottom bracket axis is selected at least slightly larger than the moment from the mass of the section of the Crank arm that carries the actuator, x the distance of this center of mass from the bottom bracket axis. This is due to the mass of the weight and the distance of its center of mass from the bottom bracket axis determines the restoring torque.

In the simplest way, the center of mass of the weight body and the center of mass of the crank arm section with the actuating element lie diametrically opposite one another with respect to the bottom bracket axis. This results in a swivel or return angle of exactly 180 °. However, this results in an unstable dead center at the lowest pedal position, at which there is theoretically no automatic pivoting back. Preferably, according to one embodiment of the invention, in the position of the crank arm in which the actuating element reaches its lowest position, the center of gravity of the weight body is laterally offset relative to the bottom bracket axis in such a way that the crank arm is reset due to the moment thereby acting. At the same time, this configuration results in an upper rest position of the actuating element, which is offset to the front in the direction of pedaling, as a result of which movement is initiated favorably.

According to a further preferred exemplary embodiment, the weight body can be changed in its position, in particular in its lateral offset. As a result, the pivoting back angle of the crank arm and thus the stroke of the actuating element can be adjusted in a simple manner according to the respective requirements.

A disadvantage of a fixed weight body is that due to the leverage ratio it must have a relatively large mass. This can be in the range between one and two kilograms. According to a particularly preferred embodiment of the invention, the weight body on the crank arm is arranged at least slightly movable in a radial plane of the bottom bracket axis. As a result, the lateral offset can be dynamically, i.e. during the crank movement, so that there is a high restoring moment at the beginning of the swinging back movement of the crank arm, which in the

The course of the swinging back movement decreases and finally goes to zero. This enables weight bodies with a lower mass. In any manner, the weight body can, for example, be displaceably guided in a corresponding guide of the second end of the crank arm. According to a particularly preferred exemplary embodiment of the invention, however, the freewheeling crank of the invention has an essentially closed housing-like box arranged in the region of the second end of the crank arm. in which at least one weight body is movably arranged at least in a radial plane of the bottom bracket axis. The weight body is guided essentially through the inner walls of the box

Although in principle a single displaceable weight body is quite conceivable in the house-like box, according to a preferred embodiment of the invention, a large number of weight bodies are arranged in a movable manner in the manner of a fill, which results in a simple and therefore inexpensive construction and a simple and continuous change in the restoring torque

The weight bodies can consist, for example, of sand-like spatial elements. However, in order to achieve a sufficient restoring moment in the smallest design, the weight bodies consist of lead balls according to a further exemplary embodiment

According to a further exemplary embodiment, the housing-like box can be at least partially filled with a liquid. This liquid can itself represent the weight body or a part thereof. This liquid is preferably a vaporization liquid, in particular an oil-like vaporization liquid to avoid operating noise and discontinuous restoring torque changes

According to a preferred exemplary embodiment, the position of the actuating elements with respect to the longitudinal axis of the crank arm can be changed. On the one hand, the necessary restoring torque can be influenced and, on the other hand, there is a possibility of adapting to the most varied of user requirements The invention further relates to a bicycle or medical exercise device with two pedal cranks which are opposite one another on both sides of the bicycle or exercise device and connected via a bottom bracket shaft, at least one of the pedal cranks being designed as a freewheeling crank according to one of the preceding claims. However, both pedal cranks are preferably designed as freewheeling cranks according to one of the preceding claims. As a result, both conventional actuation in the manner of a circular bicycle drive and a pendulum stroke drive are possible in a simple manner. Furthermore, both cranks can be operated completely independently of one another.

In the following, the invention is explained in more detail with reference to drawings which only show exemplary embodiments. It shows

1 shows a schematic illustration in a side view of a first exemplary embodiment of a freewheeling crank according to the invention;

FIG. 2 shows the freewheeling crank according to FIG. 1 in a partially broken view from above;

Fig. 3 in a view corresponding to FIG. 2

Bottom bracket area of a bicycle with two freewheel cranks in the pendulum stroke position;

4 shows a second embodiment of a freewheeling crank according to the invention with a movable weight body in a perspective view;

5 shows the weight body of the exemplary embodiment according to FIG. 4 likewise in a perspective view;

Fig. 6 in a schematic partially broken lateral

Representation of a third embodiment of a freewheel crank according to the invention; and Fig. 7 shows the embodiment of FIG. 6 in a partially broken view from above.

The freewheeling crank 1 shown in FIGS. 1 and 2 has a crank arm 2, at the first end 3 of which an actuating element 4 in the form of a rotatably fastened pedal is arranged. In the area of its second end 5, the crank arm 2 is attached to the bottom bracket 6 of a bicycle, not shown, via a freewheel 7 such that when the crank is turned in the direction of arrow F, torque is transmitted to the bottom bracket 6, while in the opposite direction, torque is decoupled and so that there is a freewheel. The freewheel 7 is arranged in a corresponding recess 8 of the crank arm 2 and is connected with its inner ring 9 in a rotationally fixed manner to the bottom bracket shaft 6.

In the area of its second end 5, a weight body 10 is arranged on the crank arm 2 and fastened there by means of two Allen screws 11 and 12. The weight body 10 together with the areas of the

Crank arm 2, which are to the right of the vertical line 13 in the illustration according to FIG. 1, has a center of gravity 14 which is offset laterally by the distance S in relation to the vertical axis 15 in the central position shown in FIG. 1. This creates a restoring moment around the bottom bracket axis in the direction of arrow G. Contrary to this restoring moment, a weight moment acts around the bottom bracket axis in the direction of arrow F due to the weight of the crank arm 2 and the actuating element 4. In accordance with the invention, the filing crank is automatically returned to the upper rest position the weight of the weight body must be selected and positioned in such a way that the restoring torque is at least slightly greater than the weight torque.

Because of the lateral offset S or T, the actuating element is in the stable upper rest position in a position which is offset in the direction of arrow F in relation to the vertical. The position of the weight body 10 and thus the offset S or T can be set by means of the Allen screws 11 and 12. This is a simple Before setting possible both for the amount of the restoring torque and for the upper rest position of the actuating element 4.

In Fig. 3, the bottom bracket area 16 of a bicycle with two freewheel cranks 1 is shown schematically in the pendulum stroke position. Two substantially identical freewheel cranks 1 are arranged opposite one another on both sides of the bicycle.

FIG. 4 shows a schematic perspective illustration of a freewheel pedal crank 101 with a crank arm 102, on the first end 103 of which an actuating element (not shown) is arranged. In the area of its second end 105 there is a recess 108 which serves to receive a freewheel (not shown) and to fasten it to a bottom bracket shaft (also not shown). In the region of the second end 105 of the crank arm 102, a weight body 110 is movably fastened to the crank arm 102. As can be seen in particular from FIG. 5, the weight body 110 has a guide pin 117, which is on the concave inner surface 118 of the weight body 1 10 is arranged and engages in a corresponding guide groove 1 19 in the crank arm 102 like a handle. The inner surface 118 is complementary to the outer surface 120 of the second end 105 of the crank arm 102. The two surfaces 118 and 120 are designed as sliding surfaces.

If the crank arm is now moved downward in the direction of arrow F when the pedal is depressed, there is a relative movement between the sliding surfaces 118 and 120 due to the inertia of the weight body 110, as indicated by the arrows V and W until the Weight body 1 10 arrives at a first end 121 of the guide groove 1 19, which cannot be seen in FIG. 4, and is carried along. Due to the eccentric arrangement of the bottom bracket axis to the axis of the pivoting movement of the weight body 110, the center of gravity of the weight body moves outwards, based on the bottom bracket axis. If the crank now turns to its lowest position when the crank is turned further and the load is lifted by the user, the weight body 110 causes the stops 121 to stop Initiation of a relatively large initial restoring torque, which leads to a rapid dynamic return of the crank to the upper rest position. For example, elastomer elements can be used for damping in the area of the stops.

In the embodiment of a freewheel crank 201 according to the invention shown in FIGS. 6 and 7, a housing-like box 222 is fastened in the region of the second end 205 of the crank arm 202, in which a plurality of weight bodies 210 in the form of lead balls are arranged in the manner of a bed. Otherwise, the interior of the box 222 is filled with an oil-like damping fluid.

If, by actuating a schematically indicated pedal 204 by a user, the crank arm is pivoted into the lowest position in the direction of arrow F, the weight bodies 210 are displaced into the position shown in FIG. 6 due to the inertia of the weight bodies 210 , whereby the center of gravity, based on the bottom bracket axis, moves outwards and a maximum restoring torque is generated. With increasing return to the upper rest position, the weight bodies 210 are shifted in the opposite direction of the arrow X and thus the restoring torque is dynamically reduced to the point of compensation with the weight moment acting through the crank arm and pedal.

As can also be seen from FIG. 6, the crank arm 202 has an engagement groove-like fastening groove 223 in which the actuating element 204 can be displaced in the direction of the longitudinal axis of the crank arm. As a result, the weight moment can be varied by changing the center of mass and the entire device can be adapted to the most varied of user requirements.

Claims

claims

1. Freewheel pedal crank, in particular for bicycles and medical exercise equipment, with a crank arm which has an actuating element in the form of a pedal or the like in the region of its first end and can be fastened in the region of its second end via a freewheel to a bottom bracket shaft such that when the Crank torque can be transmitted to the bottom bracket shaft in a first direction and torque decoupling takes place in the opposite direction, g ek ennzei chn et by at least one weight body arranged at the second end of the crank arm, which is shaped, dimensioned and positioned in such a way that when the actuating element is relieved the crank arm is automatically pivoted into a rest position, in which the crank arm extends essentially upward from the bottom bracket in relation to the direction of the weight.

2. freewheeling crank according to claim 1, characterized g ekennz ei chn et that the weight body is arranged substantially diametrically opposite the actuating element with respect to the bottom bracket axis.

3. freewheel pedal crank according to claim 1 or 2, characterized g ek en nzei chnet that in the position of the crank arm, in which the actuating element reaches its lowest position, the center of gravity of the weight body is laterally offset relative to the bottom bracket axis such that due to this effective moment the crank arm is reset.

4. freewheeling crank according to one of claims 1 to 3, characterized in that the weight body in its position, in particular in its lateral offset is variable.

5. freewheeling crank according to one of claims 1 to 4, characterized g ek en nzei ch net that the weight body is arranged on the crank arm in a radial plane of the bottom bracket axis at least slightly movable.

6. freewheel pedal crank according to one of claims 1 to 5, gekennenni chnet by a arranged in the region of the second end of the crank arm substantially closed housing-like box, in which at least one weight body at least in a radial plane of the

Bottom bracket axis is movably arranged.

7. freewheeling crank according to claim 6, characterized g ek ennzei chn et that a plurality of weight bodies are arranged movably in the manner of a bed in the housing-like box.

8. freewheel pedal crank according to claim 7, characterized ge ken nz ei chn et that the weight body consist of lead balls.

9. freewheel crank according to one of claims 6 to 8, characterized g ek ennz ei chn et that the housing-like box is at least partially filled with a liquid.

10. freewheel crank according to claim 9, characterized g e kennzei chnet that the liquid is a damping liquid, in particular an oil-like damping liquid.

11. freewheel crank according to one of claims 1 to 10, characterized g e kennzei chnet that the position of the actuating elements with respect to the longitudinal axis of the crank arm is variable.

12. Bicycle or medical exercise device with two opposite sides of the bicycle or exercise device facing each other via a bottom bracket connected pedal cranks, characterized in that at least one of the pedal cranks is designed as a freewheeling crank according to one of the preceding claims.

13. Bicycle or medical exercise device according to claim 12, characterized in that both pedal cranks are designed as freewheel pedal cranks according to one of the preceding claims.