ITPD20080271A1 - CENTRAL MECHANISM FOR BICYCLES FOR THE TRANSMISSION OF THE ROTARY MOTORBIKE OF THE PEDALS TO THE DRIVE WHEEL - Google Patents

Description

TITLE

CENTRAL MECHANISM FOR BICYCLES FOR THE

TRANSMISSION OF THE ROTARY MOTION OF THE PEDALS

TO THE DRIVE WHEEL

DESCRIPTION

The present patent relates to mechanisms for bicycles for transmitting the motion of the pedals to the driving wheel and in particular it refers to the central mechanism suitable for transmitting the forward movement to the rear driving wheel in both directions of rotation of said pedals.

In bicycles, the motion of the pedals is transmitted to the drive wheel, normally rear, by means of a system comprising at least one toothed wheel integral and coaxial to the rotation pin of the pedals, a toothed wheel coaxial to the pin of the drive wheel and a chain with links generically closed to ring that meshes with two cogwheels.

The toothed wheel coaxial to the pivot of the pedals is commonly called the crown, while the toothed wheel coaxial to the pivot of the drive wheel is commonly called the pinion. The set of pedals, cranks, crown and relative axis constitutes the central movement or mechanism.

Between the pinion and the rear driving wheel there is a mechanism called free wheel which causes the bicycle to move forward in one case only, ie only in case of pushing on the pedals such as to rotate said pinion at the same angular speed as the driving wheel. If said pinion rotates at a lower speed than said drive wheel, said free wheel mechanism does not transmit rotary motion between pinion and drive wheel. The function of said freewheel mechanism is to allow the cyclist to stop pedaling, or even pedal in the opposite direction, without affecting the forward motion of the bicycle, and also to allow the cyclist to push the bicycle by hand, for example to store it in the garage. without having the hindrance of the pedals that rotate.

A secondary effect of said freewheel mechanism is that, by moving the bicycle backwards, the pedals are rotated in the opposite direction to their normal forward pedaling direction. Many current bicycles also provide a series of pinions coaxial to the rear driving wheel, and possibly also a series of crowns coaxial to the axis of rotation of the pedals.

Appropriate derailleurs, controlled by the cyclist, engage the chain on the desired pinion or crown so as to modify the relationship between the pedals and the drive wheel.

Bicycles have the direction of rotation of thrust of the pedals identical to the direction of rotation of advancement of the drive wheel. In pedaling, almost all the muscles of the lower extremity are used and not just the strongest ones: those that extend the hip and knee. Muscle work takes place through a regular alternation between contraction and relaxation of the muscle. While pedaling, this alternation is repeated regularly.

Some muscles of the leg are however used more, for example to impart force on the pedals in the upper and anterior area of their path, while others are used in a marginal way, such as during the transfer of the pedal from the rear-upper area to the upper area. of their path.

The present patent relates to a new central mechanism for bicycles for transmitting the rotary motion of the pedals to the drive wheel always in the correct direction of advancement regardless of the direction of rotation of the pedals.

One purpose of the new central mechanism is to allow the cyclist to rotate the pedals both in the common pedaling direction and in the reverse direction, equally obtaining the transmission of the correct forward movement to the drive wheel.

Another purpose of the new central mechanism is to allow the cyclist to stop rotating the pedals without them being set in rotation by the advancement of the bicycle and the rolling of the drive wheel.

Another purpose of the new central mechanism is to allow the cyclist to make greater use of the leg muscles that are normally little used in the normal pedaling movement.

Another purpose of the new central mechanism is to allow the cyclist to rotate the pedals forwards or backwards at his choice or to alternate the two directions of rotation at will, obtaining in any case the transmission of the correct forward movement to the drive wheel.

For convenience and simplicity of presentation, forward rotation is defined as the rotation movement in the same direction of rotation of the wheel during the advancement of the bicycle, i.e. corresponding to the normal pedaling direction, and with backward rotation the rotation movement in the direction opposite to the direction of rotation of the wheel while the bicycle is moving forward. The new central mechanism for bicycles provides that the pedals are not directly fixed to the crowns but are connected to them through a rotation inversion mechanism, having its own coaxial support structure that rotates around the axis of rotation of the pedals and crowns, equipped with two locking mechanisms: a first locking mechanism which prevents the rotating structure supporting the various parts of the reversing mechanism from rotating backwards with respect to the frame, and a second locking mechanism which blocks one or more parts of the reversing mechanism rotation, thus making the pedals integral with the crowns, when the pedals are rotated forward. When the pedals are rotated forward, the first locking mechanism does not intervene, leaving the rotation inversion mechanism, and more precisely its supporting structure, free to rotate around the axis of the pedals, but the second locking mechanism intervenes, blocking the mechanism. rotation inversion so that the pedals rotate the entire rotation inversion mechanism and the crowns made integral with each other by said second locking mechanism; when the pedals are turned back the second locking mechanism allows the various parts of the reverse rotation mechanism to rotate while the first locking mechanism prevents rotation of the support or structure of the reverse rotation mechanism around the pivot pin of the pedals so that said rotation inversion mechanism transmits to the crowns the reverse rotation of the pedals reversed, obtaining the forward rotation of the crowns. The characteristics of the new central mechanism for bicycles will be better clarified by the following description with reference to the drawing tables, attached by way of non-limiting example.

Figure 1 shows a side view with some parts partially sectioned while figure 2 shows a vertical section of the new central mechanism.

The new central mechanism for bicycles for transmitting the rotary motion of the pedals to the drive wheel always in the correct direction of advancement regardless of the direction of rotation of the pedals includes:

<−> a fastening element (F) to the bicycle frame (T),

<−> a driving toothed wheel (M) coaxial to the rotation pin of the pedals (P) and rigidly constrained to the pedals or their rotation pin (P),

<−> a driven toothed wheel (C) coaxial to the rotation pin (P) of the pedals, to the crown or crowns (Z) and rigidly constrained to said crown (Z) or to said crowns (Z), having the teeth facing its center,

<−> a rotating support (S), coaxially to the rotation pin (P) of the pedals and to the crown (Z) or to the crowns (Z), having one or more toothed wheels (A1, A2), subsequently called auxiliary toothed wheels (A1, A2), suitable for transmitting the inverted rotary motion between said driving toothed wheel (M) and said driven toothed wheel (C).

The crowns (Z) and the related driven sprocket (C) are mounted coaxial to the rotation pin (P) of the pedals, but are not directly constrained to the pedals themselves.

In this example the auxiliary toothed wheels (A1, A2) are arranged in coaxial pairs, constrained to each other and rotating around an axis parallel to the rotation pin (P) of the pedals: a first auxiliary toothed wheel (A1) meshes with the toothed wheel driving gear (M) while a second auxiliary gear wheel (A2) engages the driven gear wheel (C).

In this example, three pairs of auxiliary wheels (A1, A2) are represented equally distributed around the center of the rotating support (S), but it is possible to provide a different number of pairs of auxiliary wheels (A1, A2).

There is a locking mechanism consisting of a free wheel mechanism (R1), coaxial to the rotation pin (P) of the pedals, able to constrain and release the rotating support (S) to the bicycle frame (T). Said freewheel mechanism (R1) constrains said rotating support (S) to the bicycle frame (T) preventing it from rotating backwards: when the driving sprocket (M) integral with the rotation pin (P) of the pedals is rotated backwards, the rotating support (S) does not rotate backwards but said drive sprocket (M) causes the forward rotation of said auxiliary sprockets (A1, A2) which in turn cause forward rotation of the driven sprocket (C) and of the crown (Z); when the driving sprocket (M) integral with the rotation pin (P) of the pedals is rotated forward, the rotating support (S) can rotate forward.

There is a second locking mechanism (R2) designed to block the relative movement between the auxiliary toothed wheels (A1, A2) and the driven toothed wheel (C) integral with the crown (Z) or simply to block the rotation of the toothed wheels auxiliary (A1, A2) with respect to the rotating support (S).

In particular, this second locking mechanism (R2) blocks the rotation between the auxiliary gear wheels (A1, A2) and the driven gear wheel (C) when the rotation of said auxiliary gear wheels (A1, A2) would cause the wheel to rotate backwards. driven toothed wheel (C), and allows the rotation between the auxiliary toothed wheels (A1, A2) and the driven toothed wheel (C) when the rotation of said auxiliary toothed wheels (A1, A2) causes the forward rotation of the driven toothed wheel (C ).

It is possible to provide that said second locking mechanism (R2) consists of a free wheel mechanism (R2) applied to the auxiliary wheels (A1, A2), or it is possible to provide that said second locking mechanism (R2) consists of a element able to fit between the teeth of each second auxiliary toothed wheel (A2) and of the driven toothed wheel (C), preventing their relative movement, when the rotation of said second auxiliary toothed wheels (A2) would cause the backward rotation of the toothed wheel conduct (C).

The operation of the new central mechanism for bicycles is described below, with reference to the example described above. The considerations set out below are to be considered conceptually valid also for central mechanisms implemented in a different way but based on the same theoretical assumptions.

During forward pedaling, the pedals rotate the drive sprocket (M) forward which would cause the auxiliary sprockets (A1, A2) to rotate backwards.

Reverse rotation of the auxiliary sprockets (A1, A2) would cause reverse rotation of the driven sprocket (C), but this rotation is prevented by the second locking mechanism (R2).

The freewheel mechanism (R1) between the rotating support (S) and frame (T) of the bicycle does not oppose the forward rotation of said rotating support (S) with respect to the frame (T) of the bicycle.

It follows that the forward rotation of the pedals and of the driving toothed wheel (M) causes the forward rotation of the driven toothed wheel (C) and therefore also of the crowns (Z) obtaining the known pedaling motion.

When pedaling backwards, the pedals rotate the drive sprocket (M) backwards, which causes the auxiliary sprockets (A1, A2) to rotate forward.

Forward rotation of the auxiliary sprockets (A1, A2) causes forward rotation of the driven sprocket (C).

The second locking mechanism (R2) between the auxiliary toothed wheels (A1, A2) and the driven toothed wheel (C) does not oppose the rotation of said auxiliary toothed wheels (A1, A2) and said driven toothed wheel (C).

The freewheel mechanism (R1) between the rotating support (S) and frame (T) of the bicycle opposes the backward rotation of said rotating support (S) and therefore said auxiliary sprockets (A1, A2) do not rotate around the rotation pin (P) of the pedals but only around their own axis. In this case there is transmission of rotation between the driving toothed wheel (M) and the driven toothed wheel (C) by means of the auxiliary toothed wheels (A1, A2).

It follows that the backward rotation of the pedals and of the driving sprocket (M) causes the forward rotation of the driven sprocket (C) and therefore also of the crowns (Z) obtaining motion on the chain and sprockets, also in this case. pedaling forward.

In this example the auxiliary sprockets (A1, A2) have different diameters to keep the pedaling ratio equal both forward and backward. Alternatively, it is possible to provide that said two auxiliary wheels (A1, A2) have the same diameter or that there is only one auxiliary wheel which simultaneously engages the driving toothed wheel (M) and the driven toothed wheel (C).

These are the schematic modalities sufficient for the skilled person to realize the invention, consequently, in concrete application there may be variations without prejudice to the substance of the innovative concept.

Therefore, with reference to the preceding description and to the attached table, the following claims are expressed.

Claims (8)

CLAIMS 1. Central mechanism for bicycles, characterized by the fact of having the pedals not directly fixed to the crowns (Z), but connected to them through a rotation inversion mechanism, having its own support structure (S) that is coaxial and rotating around the axis of rotation (P) of the pedals and crowns (Z), and where said central mechanism is equipped with at least two locking mechanisms (R1, R2) of which a first locking mechanism (R1) prevents said rotating support structure (S) of the various parts of the reversing mechanism to rotate back relative to the frame (T), and a second locking mechanism (R2) which locks one or more parts of the reversing mechanism when the pedals are rotated forward. 2. Central mechanism for bicycles, as per claim 1, characterized in that said rotation inversion mechanism comprises: - a fastening element (F) to the bicycle frame (T), - a driving sprocket (M) coaxial to the rotation pin (P) of the pedals and rigidly constrained to the pedals or their rotation pin (P); - a driven toothed wheel (C) coaxial to the rotation pin (P) of the pedals, to the crown (Z) or to the crowns (Z) and rigidly constrained to said crown or to said crowns (Z), - a rotating support (S), coaxially to the rotation pin (P) of the pedals and to the crown (Z) or to the crowns (Z), having one or more auxiliary toothed wheels (A1, A2) suitable for transmitting the inverted rotary motion between said driving toothed wheel (M) and said driven toothed wheel (C). 3. Central mechanism for bicycles, as per claims 1, 2, characterized in that the auxiliary sprockets (A1, A2) are arranged in coaxial pairs, constrained to each other and rotating around an axis parallel to the rotation pin (P) of the pedals, and where the first auxiliary toothed wheel (A1) meshes with the driving toothed wheel (M) and where the second auxiliary toothed wheel (A2) meshes with the driven toothed wheel (C). 4. Central mechanism for bicycles, as per claims 1, 2, 3, characterized in that the first locking mechanism (R1) is placed and acts between said rotating support (S) and the fastening element (F) to the frame of the bicycle (T). 5. Central mechanism for bicycles, as per claim 4, characterized by the fact that said first locking mechanism (R1) is constituted by a free wheel mechanism (R1), coaxial to the rotation pin (P) of the pedals, able to constrain and releasing the rotating support (S) to the bicycle frame (T), and where said freewheel mechanism (R1) constrains said rotating support (S) to the bicycle frame (T) preventing it from rotating backwards. 6. Central mechanism for bicycles, as per claims 1, 2, 3, characterized in that said second locking mechanism (R2) is constituted by a mechanism adapted to block the relative movement between the auxiliary sprockets (A1, A2) and the driven toothed wheel (C) integral with the crown (Z) or simply adapted to block the rotation of the auxiliary toothed wheels (A1, A2) with respect to the rotating support (S). 7. Central mechanism for bicycles, as per claim 6, characterized in that said second locking mechanism (R2) consists of a free wheel mechanism (R2) applied between the rotating support (S) and the auxiliary wheels (A1, A2 ). 8. Central mechanism for bicycles, as per claim 6, characterized in that said second locking mechanism (R2) is constituted by an element able to be inserted between the teeth of each second auxiliary toothed wheel (A2) and of the driven toothed wheel ( C), preventing their relative movement, when the rotation of said second auxiliary toothed wheels (A2) would cause the driven toothed wheel (C) to rotate backwards.