EP2421745A1

EP2421745A1 - Vehicle provided with winch transmission

Info

Publication number: EP2421745A1
Application number: EP10714282A
Authority: EP
Inventors: Agostino Lucarelli
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-04-22
Filing date: 2010-04-20
Publication date: 2012-02-29
Also published as: WO2010121999A1; IT1393646B1; ITMC20090090A1

Abstract

A vehicle (1) is described, comprising a driving shaft (2), a driven shaft (6) and a transmission (5) to transmit the rotation of the driving shaft (2) to the driven shaft (6). The driven shaft (6) is a crank shaft that comprises a first housing section (61) and a second housing section (63) in which a first group of pulleys (P1, P3, P5) and a second group of pulleys (P7, P9, P11) are respectively mounted. A third group of pulleys (P2, P4, P6, P8, P10) is mounted on the driving shaft (2) and a rope (7) is alternatively returned to the pulleys of the driven shaft and to the pulleys of the driving shaft. Lock devices (D1, D2) are provided to lock in sequential exclusive mode the rotation of two pulleys (P4, P8) of the driving shaft.

Description

Vehicle provided with winch transmission

The present patent application for industrial invention relates to a vehicle provided with winch transmission, and in particular to a bicycle.

Although specific reference is made to a bicycle, it is understood that the present invention is extended to any vehicle provided with transmission to transmit motion from a drive shaft to one or more driving wheels.

As it is known, a bicycle comprises a chain transmission. By means of the pedals the cyclist puts into rotation a driving shaft joined to a toothed wheel that engages with a chain that in turns rotates a sprocket wheel joined to the hub of the driving wheel. Such a chain-driven transmission system requires high motive power to be applied to the driving shaft, making motion extremely difficult in case of climbing. In order to solve such a disadvantage bicycles are generally provided with multiple sprocket wheels and multiple gears of different diameters in order to adjust the speed ratio according to the type of route. A derailleur gear allows the user to select the suitable sprocket wheel and gear.

However, it must be noted that when using a low speed ratio (small gear and large sprocket wheel) during climbing, the cyclist makes a lower effort, but must increase the number of pedal thrusts to make the same route compared to a higher speed ratio. The purpose of the present invention is to eliminate the drawbacks of the known art, by devising a vehicle provided with winch transmission device that is practical, versatile, inexpensive and simple to make.

These purposes are achieved by the present invention, the features of which are claimed in the independent claim 1 . Advantageous embodiments are disclosed in the dependent claims.

The vehicle of the invention comprises:

- a frame,

- a driving shaft revolvingly mounted in the frame around a horizontal axis of rotation,

- a driven shaft revolvingly mounted in the frame around an axis of rotation parallel to the axis of the driving shaft, said driven shaft being connected to at least one driving wheel, and - a transmission to transmit the rotation of the driving shaft to the driven shaft.

The driven shaft is a crank shaft that comprises at least a first housing section and a second housing section with equally spaced parallel axes in opposite directions with respect to the axis of rotation of the driven shaft, The transmission comprises:

- a first group of at least two pulleys revolvingly mounted on said first housing section of the crank shaft,

- a second group of at least two pulleys revolvingly mounted on said second housing section of the crank shaft, - a third group of at least three pulleys revolvingly mounted on said driving shaft, and

- a rope alternately returned to the pulleys of the driven shaft and the pulleys of the driving shaft, in which the two ends of the rope are fixed respectively to the two ending pulleys of the driven shaft. The transmission also comprises lock devices to lock the rotation of pulleys, which are designed to lock in exclusive sequential mode:

- a first pulley of the driving shaft connected with the rope to two pulleys of the first housing section of the driven shaft, and

- a second pulley of the driving shaft connected with the rope to two pulleys of the second housing section of the driven shaft.

Additional characteristics of the invention will become evident from the detailed description below, which refers to a merely illustrative, not limiting, embodiment, as shown in the enclosed figures, wherein:

Fig. 1 is a perspective diagrammatic view showing the frame of a bicycle provided with transmission of the invention;

Fig. 2 is a perspective view of the transmission of Fig. 1 in initial position; Fig. 3 is a top view of the transmission of Fig. 2 after the driven shaft has made a 90° rotation with respect to the position of Fig. 2; and

Fig. 4 is a perspective view as Fig. 2, in which the driven shaft has made a 180° rotation with respect to Fig. 2. Referring to the figures, the vehicle provided with winch transmission according to the present invention is described. Fig. 1 is a partial view of a vehicle (1 ). The vehicle (1 ) comprises:

- a frame (4),

- a driving shaft or primary shaft (2), - a driven shaft or secondary shaft (6), and

- a transmission (5).

The driving shaft (2) is revolvingly mounted in the frame (4) in order to rotate around an axis (A). In case of a bicycle, the driving shaft (2) is the crank shaft. The driven shaft (6) is revolvingly supported by the frame (4) in order to rotate around an axis (B). The driven shaft (6) is joined to a driving wheel

(30), for example by means of a flywheel (31 ).

The transmission (5) connects the driving shaft (2) with the driven shaft (6), in such a way that the rotation of the driving shaft (2) causes a rotation of the driven shaft (6).

As shown in Figs. 2 and 3, the driven shaft (6) is a crank shaft that comprises two ends (3, 65) disposed on the same horizontal axis of rotation

(B) and revolvingly supported by the frame (4). The first end (3) is connected to the flywheel (31 ), whereas the second end (65) is supported by the frame. The axis of rotation (B) of the driving shaft (6) is parallel to the axis of rotation

(A) of the driven shaft and the two axes (A, B) lay on the same basically horizontal plane with respect to the ground.

Starting from the end (3), the craft shaft (6) comprises a section (60) disposed at right angle with respect to the axis of rotation (B) that continues with a first housing section (61 ) parallel to the axis of rotation (B), which continues with an intermediate parallel section (62) with double length than the section (60) that continues with a second housing section (63) parallel to - A -

the first housing section (61 ) that continues with a parallel section (64) with same length as the section (60), which ends with the end (65).

Three pulleys (P1 , P3, P5) are revolvingly mounted in the first housing section (61 ) of the crank shaft; and other three pulleys (P7, P9, P1 1 ) are revolvingly mounted in the second housing section (63). The six pulleys (P1 , P3, P5, P7, P9, P1 1 ) are equally spaced.

Five equally spaced pulleys (P2, P4, P6, P8, P10) are revolvingly mounted on the driving shaft (2), with the same distance of the pulleys (P1 , P3, P5, P7, P9, P1 1 ) of the crank shaft. The orthogonal plane of the axis of each pulley (P2, P4, P6, P8, P10) of the driving shaft passes through the medium point of the distance between two pulleys (P1 , P3, P5, P7, P9, P1 1 ) of the crank shaft.

A rope (7) is returned to the eleven pulleys (P1 , P2, P3, P4, P5, P6,

P7, P8, P9, P10, P1 1 ). A first end (70) of the rope (7) is locked in the first pulley (P1 ) of the crank shaft, so that the rope (7) is alternatively returned to the pulleys of the driving shaft and of the crank shaft. The second end (71 ) of the rope (7) is locked at the last pulley (P1 1 ) of the crank shaft.

Referring to Fig. 3, the second pulley (P4) and the second last pulley

(P8) of the driving shaft (2) are provided with lock devices (D4, D8) to lock rotation on the driving shaft. The lock devices (D4, D8) are activated and deactivated in sequential mode. The first lock device (D4) remains active when the axis of the first housing section (61 ) of the crank shaft is situated above the axis of rotation (B) of the crank shaft (Fig. 2). Instead, the second lock device (D4) remains active when the axis of the second housing section (63) of the crank shaft is situated above the axis of rotation (B) of the crank shaft (Fig. 4).

Switching from lock device (D4) to lock device (D8) is carried out when the axis of the first housing section (61 ), the axis of the second housing section (63) and the axis of rotation (B) of the crank shaft lay on the same plane (Fig. 3).

In a mechanical solution, the lock devices (D4, D8) can be controlled in exclusive sequential mode by means of a cam synchronized with the movement of the crank shaft (6). To that end the second end (65) of the crank shaft can be connected to the cam by means of a belt.

In an electronic solution, a sensor, such as an encoder, can be mounted on the crank shaft (6) to detect the exact position of the crank shaft and accordingly send control signals to a control unit that activates the lock devices (D4, D8).

Following is a description of the operation of the transmission of the invention.

Referring to Fig. 2, an initial situation is considered, in which the axis of the first housing section (61 ) is above the axis of rotation (B) of the crank shaft (6). In such a situation the pulley (P4) is locked, whereas the pulley (P8) is free. A rotation of the driving shaft (2) in the direction of the arrow (R) causes traction of the section of rope (7) that goes from the pulley (P3) to the pulley (P4) in the direction of the arrow (F1 ). Consequently, the first housing section (61 ) of the crank shaft that houses the pulleys (P1 , P3) is pulled in the direction of the arrow (F1 ), causing the rotation of the crank shaft in the direction of the arrow (R1 ).

The crank shaft reaches the position in which the axis of the first housing section (61 ), the axis of the second housing section (63) and the axis of rotation (B) of the crank shaft lay on the same plane (Fig. 3). In this position the pulley (P4) is unlocked and the pulley (P8) is locked. Because of the flywheel inertia, the crank shaft (6) continues on rotating passing beyond the dead point in which switching of the lock devices (D4, D8) of the pulleys occurs. Accordingly, the second housing section (63) arrives above the axis of rotation (B) of the crank shaft. In such a situation, which is shown in Fig. 4, the pulley (P8) is locked, and therefore the rotation of the driving shaft (2) in the direction of the arrow (R) causes traction of the section of rope (7) that goes from the pulley (P9) to the pulley (P8) in the direction of the arrow (F2). Consequently, the second housing section (63) of the crank shaft that houses the pulleys (P9, P1 1 ) is pulled in the direction of the arrow (F2), causing the rotation of the crank shaft in the direction of the arrow (R2). The figures show a crank shaft (6) with two housing sections (61 , 63) that respectively house two groups of three pulleys (P1 , P3, P5) and (Pl, P9, P1 1 ) and a group of five pulleys (P2, PA, P6, P8, P10) housed on the driving shaft (2). However, the invention also extends to a crank shaft provided with more than two housing sections and at least two pulleys can be housed in each housing section. In any case a number of pulleys equal to the number of pulleys of the driven shaft reduced by one is mounted in the driving shaft.

Although the figures show a crank shaft disposed on the right of the wheel that provides for connection arms (60, 62, 64) on the same plane, a crank shaft with connection arms staggered by 90° can be provided, in such a way to avoid the dead points in which the connection arms lay on a horizontal plane. Alternatively, two crank shafts, of which one on the right and one on the left of the wheel with connection arms staggered by 90° can be provided.

Numerous variations and modifications can be made to the present embodiment of the invention by an expert of the art, while still falling within the scope of the invention as claimed in the enclosed claims.

Claims

1 ) Vehicle (1 ) comprising:

- a frame (4),

- a driving shaft (2) revolvingly mounted in the frame (4) around an axis of rotation (A), - a driven shaft (6) revolvingly mounted in the frame (4) around an axis of rotation (B) parallel to the axis (A) of the driving shaft, the said driven shaft (6) being connected to at least one driving wheel (3), and

- a transmission (5) to transmit the rotational movement of the driving shaft (2) to the driven shaft (6), characterized in that the driven shaft (6) is a crank shaft that comprises at least a first housing section (61 ) and a second housing section (63) with equally spaced parallel axes in opposite directions with respect to the axis of rotation (B), and said transmission (5) comprising: - a first series of at least two pulleys (P1 , P3, P5) revolvingly mounted in the first housing section (61 ) of the crank shaft,

- a second series of at least two pulleys (P7, P9, P1 1 ) revolvingly mounted in the second housing section (63) of the crank shaft,

- a third series of at least three pulleys (P2, P4, P6, P8, P10) revolvingly mounted on the driving shaft (2),

- a rope (7) alternately returned to the pulleys of the driven shaft and to the pulleys of the driving shaft, in which the two ends (70, 71 ) of the rope are fixed respectively to the two ending pulleys (P1 , P1 1 ) of the driven shaft (6), and - locking devices (D1 , D2) to lock the rotation of pulleys designed to lock in exclusive sequential mode:

- a first pulley (P4) of the driven shaft connected with the rope (7) to two pulleys (P3, P5) of the first housing section (61 ) of the driven shaft, and - a second pulley (P8) of the driving shaft connected with the rope (7) to two pulleys (P7, P9) of the second housing section (63) of the driven shaft.

2) Vehicle according to claim 1 , characterized in that the said locking devices (D1 , D2) are actuated by a cam synchronized with the rotation of the driven shaft (6).

3) Vehicle according to claim 1 , characterized in that the said locking devices (D1 , D2) are actuated by an electronic control unit connected to an encoder that detects the position of the driven shaft (6).

4) Vehicle according to any of the above claims, characterized in that the driven shaft (6) is connected with a flywheel (31 ).

5) Vehicle according to any of the above claims, characterized in that it is a bicycle in which the driving shaft (2) is connected to pedals (20).

6) Vehicle according to any of the above claims, characterized in that it is a motorcycle in which the driving shaft (2) is connected to a motor. 7) Vehicle according to any of the above claims, characterized in that the crank shaft is provided with connection arms that lay on planes staggered by 90°.

8) Vehicle according to any of the above claims, characterized in that it comprises two crank shafts, one on the right side and one on the left side of the driving wheel (30), provided with connection arms that lay on planes staggered by 90°.