WO2017137923A1

WO2017137923A1 - Dual arm single-shock-absorber assembly for a pair of wheels of a velocipede

Info

Publication number: WO2017137923A1
Application number: PCT/IB2017/050717
Authority: WO
Inventors: Marco Brogi
Original assignee: Bromas-Log S.R.L.
Priority date: 2016-02-09
Filing date: 2017-02-09
Publication date: 2017-08-17
Also published as: ITUB20160588A1

Abstract

A dual arm single shock absorber assembly for reduced track velocipedes equipped with two wheels arranged on the same axle. The single shock absorber assembly makes it possible for a velocipede to tilt and promptly face up to changes of trajectory, while keeping an optimum grip on the road surface, even in the case of bumpy grounds. The single shock absorber assembly is very compact and light and is well suited to being applied to folding velocipedes, which generally feature small dimensions and are equipped with reduced diameter wheels.

Description

DESCRIPTION

Title

Dual arm single-shock-absorber assembly for a pair of wheels of a velocipede

Technical field

The present invention concerns the sector of velocipedes equipped with one or several pairs of wheels arranged on one and the same axle, i.e. wheels that are substantially coaxial to each other whenever the vehicle is at rest, and capable of tilting while running, for instance in order to take bends and change trajectory.

More specifically, the present invention concerns a dual arm suspension for a pair of wheels of one and the same axle of a velocipede of the mentioned type, said suspension being equipped with one shock absorber assembly.

Present status of the art

Velocipedes are known for a long time equipped with three or more wheels, for instance tricycles and four-wheel cycles, wherein at least one pair of wheels is arranged on one and the same axle, for instance the front axle or the back axle.

Velocipedes of this type generally feature a little wide track, and this characteristic of their own makes them different from vehicles such as, for instance, cars or motorcycles with sidecar having definitely bigger dimensions and weight.

In said vehicles, the pair of coaxial wheels determines a reduced track and this results in a number of known disadvantages including, amongst others, a reduced stability and a reduced grip on the road surface while taking bends .

In general, the cyclistics of such velocipedes does not allow to easily tilt the vehicle, thus preventing the possibility of keeping high speeds while taking bends, whereby, even if using steering wheels, it is not generally possible to promptly set changes of trajectory and the steering angles are generally very wide.

These problems are even stronger in the case of velocipedes with small-diameter wheels such as, for instance, folding velocipedes, i.e. those vehicles which are equipped with special construction arrangements which make it possible to disassemble them in order to reduce their overall dimensions and make transportation easier.

In order to obviate such problems, three- or multi-wheel velocipedes have been implemented with time, equipped with such suspensions as to enable the pair of coaxial wheels to tilt while running, so as to make it possible to take bends more efficiently and at higher speed, while retaining an appropriate grip on the road surface.

These velocipedes using tiltable wheels guarantee a greater stability and driving safety as compared to those equipped with wheels only, be they steering or not, the axle of which is always perpendicular to the plane where the frame lies .

It is also known that using shock absorber assemblies suitable for absorbing the oscillations of the suspensions makes it possible to increase comfort and drivability in a vehicle.

A system of this type is disclosed, for instance, in German patent DE 19838328, which describes a pedal vehicle equipped with independent suspensions capable of tilting together with the frame to take bends; each wheel is mounted on an independent suspension assembly of the articulated quadrilateral type.

A further example of a suspension assembly of the type described so far is that disclosed in English patent GB 2374327.

These systems shall be equipped with springs and shock absorbers which, besides providing a contact with the road surface in any driving conditions, provide a very high safety and comfort, while also making it possible to easily face up to irregular and bumpy road surfaces.

An example is disclosed in patent application WO 97/21583, which describes a vehicle equipped with at least three wheels, two of which connected to the frame via a two-arm suspension system equipped with shock absorbers and suspensions .

However, the systems known so far are rather complex and formed of a high number of component parts, in that they generally comprise one shock absorber assembly for every wheel of the axle.

Furthermore, the known systems are bulky and heavy, which characteristics are badly suited to their use in pedal- operated velocipedes, wherein lightness is one of the outstanding requirements and in particular for folding cycles, which comprises reduced-size frames and/or wheels.

Objects and summary of the invention

The single shock absorber assembly according to the present invention makes it possible to obviate the typical problems of the devices presently known in the status of the art, while providing very reduced overall dimensions and weight. These advantages and others are achieved by using a dual arm single shock absorber assembly that is extremely compact and features very much reduced dimensions, formed of a reduced number of component parts, capable of providing an optimum grip on the road surface in any driving conditions, while allowing to tilt the velocipede to efficiently take bends and changes of trajectory at a high speed and simultaneously providing comfort and stability even in the case of irregularities in the road surface .

Reduced dimensions and lightness make the assembly according to the present patent application particularly advantageous for its application to any types of three- or more wheel velocipedes featuring a reduced track and in particular to velocipedes equipped with reduced size wheels, such as, for instance, folding cycles.

A single shock absorber assembly according to the present patent application comprises two torsionally rigid side arms hinged to the median part of a central longitudinal element, also torsionally rigid, said side arms being rotating about an axis substantially parallel to the axle of the wheels of the velocipede.

The free end of each of the two side arms is rotationally coupled with a respective wheel.

The inner end of the central longitudinal element is functionally connected to the frame of the velocipede, whereas the outer end is hinged to a first terminal of a shock absorber.

The second terminal of said shock absorber is rotationally connected to the outer end of an arc-shaped element, whose inner end is rotationally coupled with the median part of said central longitudinal element and is free to rotate about the same axis about which the side arms are hinged.

The shock absorber is of a known type and comprises, in its most common form, at least one elastic element and one dissipative element, other solutions being also possible. The median part of the arc-shaped element is coupled with the central section of a steerable pin, by way of at least one articulated joint; the opposite ends of said steerable pin are each connected to the median part of one of the side arms via articulated joints. Whenever the velocipede is in a static equilibrium or is moving in a rectilinear motion, said central longitudinal element and said arc-shaped element lie in a vertical plane orthogonal to the road surface, whereas the axles of the two wheels are parallel to the road surface.

Whenever a biker laterally tilts the velocipede, for instance in order to take a bend or to make a change of trajectory, the arms rotate about their own axis, in a sense opposite to each other, so that the two wheels tilt jointly with the vehicle and keep in contact with the road surface .

The dual arm single shock absorber assembly makes it possible for the two wheels of a velocipede to assure an optimum grip on the road surface because the two side arms are capable of rotating independently about their own axis, being connected to each other via a steerable pin whose central section is housed in an articulated joint which is movable in the vertical plane, so as to be capable of varying its own position with respect to the axle on which the side arms are hinged, according to the solutions specified in the detailed description which follows.

The loads are advantageously distributed on the one shock absorber which absorbs the stresses transmitted by the wheels to the arms and then by the arms to the shock absorber itself via the arc-shaped element.

The shock absorber definitively absorbs the loads by operating between the arc-shaped element and the central longitudinal element.

In this way, comfort and driving stability are ensured even in the case of bumpy road surfaces, including depressions and humps .

Should the assembly be applied to the driving wheels of a three- or multi-wheel velocipede, each wheel can be equipped with means of transmission suitable for receiving the rotational motion produced by an engine or by a biker' s muscular strength, in the latter case, for instance, via pedals .

Advantageously can such means of transmission consist of toothed pinions coupled with belts, chains, or other flexible means of motion transmission.

Conversely, whenever the assembly according to the present invention is applied to the steering wheels of a velocipede, the central longitudinal element is turnable with respect to the frame and is capable of rotating about an axis substantially perpendicular to the axle of the wheels, and is connected to steering devices in such a way as to enable the biker to vary the angle of rotation of said central element about its own axis, by acting onto said steering devices.

Brief description of the drawings

Figure 1 shows an exploded view of a possible embodiment of the single shock absorber assembly applied to the driving wheels of a velocipede; the figure shows two side arms (3, 4) each coupled with a respective wheel (1, 2), a central longitudinal element (5), a shock absorber (7), an arc- shaped element (6), a steerable pin (8), an oscillating element (9), and means of transmission (11, 12, 13, 14, 15, 16) transmitting motion to the wheels (1, 2) . The figure also shows the axis (Y) about which the pin (8) rotates and the axis (X) which the arms (3, 4) and the arc-shaped element (6) are hinged to; the first shaft (31) coaxial to the axis (X) is also visible.

Figure 2 shows a single shock absorber assembly applied to the driving wheels of a velocipede, one wheel (2) having being removed. The figure shows the seat (32) of the second shaft parallel to the axis (X) . Figure 3 shows a single shock absorber assembly applied to the driving wheels of a velocipede, one wheel (2) and the shock absorber (7) having been removed.

Figure 4 shows a side view of a single shock absorber assembly applied to the driving wheels of a velocipede, the two side arms (3, 4) being tilted differently.

Figure 5 shows a front view of a single shock absorber assembly applied to the driving wheels of a velocipede, the wheels (1, 2) being tilted to take a bend and the two side arms (3, 4) being rotated about their own axis, in opposite senses one with respect to the other.

Figure 6 shows a view of a single shock absorber assembly applied to the steering wheels of a velocipede, wherein the axis (Z) about which the central longitudinal element (5) rotates is visible; a support (55) is also visible for connecting the central longitudinal element (5) to steering devices .

Figure 7 shows a side view of a four-wheel velocipede, equipped with a single shock absorber assembly applied to the two rear driving wheels and a single shock absorber assembly applied to the two front steering wheels. The single shock absorber assembly applied to the front steering wheels is connected to steering devices, comprising a rigid rod (22) connected to the support (55) of the longitudinal element (5) and a rotary pulley (21), connected to two half-handlebars rotationally coupled with the frame by way of two cables (19, 20) ; in the figure, the right half-handlebar (18) is visible.

Figure 8 shows an enlarged view of a single shock absorber assembly applied to the front steering wheels of the velocipede shown in figure 7.

Figure 9 shows a top view of the velocipede shown in figure 7, wherein in particular the two half-handlebars (17, 18) of the steering system are visible.

Figure 10 shows an exploded view of a preferred version of a single shock absorber assembly applied to the driving wheels of a velocipede; the elements of figure 1, but the oscillating element (9), are visible. The freedom of movement of the latter guaranteed in the version according to the previous figure 1 is provided, in this case, by associating the first shaft (31) with the arc-shaped element (6), not by way of a rotational coupling, but rather internally to a slot (61), so as to make a reciprocal rototranslation possible.

Figure 11 and Figure 12 show perspective views of the version shown in Figure 10.

Figure 13 shows a top view of the same version as shown in the three previous figures, wherein the trace of the cutting plane of the cross-section shown in Figure 14 is highlighted .

Figure 14 shows a cross-sectional view of a single shock absorber assembly which highlights the slot (61) that receives the first shaft (31) .

Detailed description of an embodiment of the invention

In its simplest embodiment, the single shock absorber assembly for three- or multi-wheel velocipedes according to the present patent application comprises two torsionally rigid side arms (3, 4), whose inner end is rotationally coupled with the median part of a central longitudinal element (5) of the frame, according to an axis (X) substantially parallel to the axle of the wheels (1, 2), whereas a respective wheel (1, 2) is rotationally connected to the outer end of each of said side arms (3, 4) .

Said central longitudinal element (5) lies in a central- line vertical plane of the device, equally spaced from the planes determined by the wheels (1, 2), and presents an inner end, integrally connected to the frame during the normal use of the velocipede, and an outer end rotationally connected to the terminal of the shock absorber (7); the other terminal of said shock absorber (7) is rotationally connected to the outer end of an arc-shaped element (6) which lies in said vertical plane and whose inner end is rotationally connected to the median part of said element (5), according to the same axis (X) about which the arms (3, 4) rotate.

The two side arms (3, 4) are connected to each other by a steerable pin (8) whose central section is coupled with said arc-shaped element (6) by way of at least one articulated joint.

According to a possible embodiment, the connection between the central section of said steerable pin (8) and the arc- shaped element (6) is implemented by an element (9) oscillating in said vertical plane. In this case, the first end of said oscillating element (9) is connected to the central section of said steerable pin (8) by way of a spherical articulation which allows both a rotation of the pin (8) about an axis (Y) and a limited oscillation with respect to an axis lying in said vertical plane; the second end of said oscillating element (9) is rotationally connected to the central part of the arc-shaped element (6) .

In an alternative embodiment, the central section of said steerable pin (8) is connected to the central part of the arc-shaped element (6) by way of a spherical articulation and the inner end of said arc-shaped element (6) is rototranslationally coupled with the median part of said central longitudinal element (5) by way of a slot (61) which allows said axis (X) to translate perpendicularly to the direction identified by the axis (X) itself. The connection of the end of said steerable pin (8) to its respective arms (3, 4) is also of a spherical type and makes it possible for the pin to rotate about the axis (Y) as well as for the pin (8) to steer with respect to the arms (3, 4) . The connection to the ends of the steerable pin (8) is implemented in the median part of the arms (3, 4) .

According to an advantageous embodiment, said spherical articulations comprise ball bearings, or bronze bushings, of a steerable type housed in said oscillating element (9) and in said side arms (3, 4) .

According to a possible embodiment, specific for the application of a single shock absorber assembly to the driving wheels (1, 2) of a velocipede, the latter are connected to means of motion transmission suitable for transferring to said wheels (1, 2) the rotary motion produced by an engine or preferably by a biker' s legs by way of pedals. In this embodiment, a respective toothed pinion (11, 12) is coaxially keyed to each of said driving wheels (1, 2) . Each of said toothed pinions (11, 12) is connected to a respective second toothed pinion (13, 14) by way of a belt, a chain, or another flexible motion transmission device. Each of said second toothed pinions (13, 14) is keyed to a first shaft (31) coaxial to said axis (X) ; to the same first shaft (31) there is also keyed a third toothed pinion (15) which is connected, by way of a chain, a belt or other known means of motion transmission, to a fourth toothed pinion (16) , the latter being keyed to a second shaft parallel to said axis (X) driven into rotation by an engine or by the biker. The seat (32) of said second shaft parallel to the axis (X) is visible, for instance, in figure 2.

Advantageously, can the single shock absorber assembly according to the present invention comprise at least one braking device such as, for instance, a disc brake. In an advantageous embodiment, said braking device is mounted on said second shaft parallel to the axis (X) and the fourth toothed pinion (16) is connected to said second shaft parallel to the axis (X) by way of a freewheel device such as a ratchet gear. Alternatively, can said braking device be mounted on said first shaft (31) .

According to an alternative embodiment specific to the application of the single shock absorber assembly to the steering wheels of a vehicle, the central longitudinal element (5) is not integrally connected to the frame of the velocipede, but is rather turnable with respect to the latter, being it capable of rotating about an axis (Z) substantially perpendicular to said axis (X) ; also, in this case, said central longitudinal element (5) is further connected to a steering device, so that a biker can act on said devices, to steer the velocipede and vary the angle of rotation of said central longitudinal element (5) about said axis (Z) .

For instance, the central longitudinal element (5) might accommodate, on the upper side, a roller bearing suitable for rotationally engaging a pin projecting from the frame of the velocipede, said pin having an axis (Z) of symmetry substantially perpendicular to said axis (X) .

Preferably can these steering devices be comprised of two half-handlebars (17, 18), each of which is rotationally coupled with the frame of the vehicle, two sheathed cables (19, 20), each of which is connected at one end to either of said two half-handlebars (17, 18) so that rotating one half-handlebar results in stretching its respective cable, a pulley (21) housed in the frame and connected to these two cables (19, 20) so that, whenever a cable is stretched, the pulley rotates in one sense, whereas the pulley rotates in the opposite sense whenever the other cable is stretched, a rigid rod (22) eccentrically connected to such pulley (21) so that rotating said pulley (21) results in a linear motion of the rod (22), said rod (22) being connected at the opposite end to a support (55) of said central longitudinal element (5), said support being mounted eccentrically with respect to the center of rotation about said axis (Z), so that the rectilinear movement of the rod (22) makes said central longitudinal element (5) rotate about said axis (Z) .

Claims

1. A single shock absorber assembly for a pair of wheels (1, 2) of a three-wheel or multi-wheel velocipede, comprising two torsionally rigid side arms (3, 4), each of which features an outer end which a respective wheel (1, 2) is rotationally connected to, and an inner end rotationally coupled, according to an axis (X) substantially parallel to the axles of the wheels (1, 2), with the median part of a central longitudinal element (5), the latter lying in a centerline vertical plane equally spaced from the planes defined by the two wheels (1, 2) and being functionally connected to the frame of the velocipede by its own inner end, characterized in that the outer end of said central longitudinal element (5) is rotationally connected to the first end of a shock absorber (7), whose second end is rotationally connected to the outer end of an arc-shaped element (6) lying in said vertical plane and featuring an inner end rototranslationally connected to the median part of said longitudinal element (5), rotation taking place about said axis (X) and translation taking place orthogonally to the direction of said axis (X) by way of a slot (61), the median part of each of said arms (3, 4) being connected via spherical articulations to the two opposite ends of a steerable pin (8), whose central section is connected via at least one spherical articulation to said arc-shaped element (6) .

2. A single shock absorber assembly according to the previous claim, characterized in that said spherical articulations which connect said steerable pin (8) to said arc-shaped element (6) and to each of said side arms (3, 4) comprise ball bearings, or bronze bushings, of a steering type .

3. A single shock absorber assembly according to any of the previous claims, characterized in that each of said wheels (1, 2) is coupled with means of motion transmission suitable for transferring the rotary motion produced by an engine or by a biker's legs via pedals to said wheels (1, 2) .

4. A single shock absorber assembly according to the previous claim 3, characterized in that said motion transmission means comprise two toothed pinions (11, 12) each of which is coaxially keyed to one of said wheels (1, 2) and is connected via a flexible motion transmission device, to a second toothed pinion (13, 14), each of the latter is keyed to a shaft (31) coaxial to said axis (X), a third toothed pinion (15) also being keyed to said shaft (31) and connected via a flexible motion transmission device to a fourth toothed pinion (16), the latter being keyed to a shaft (32) parallel to said axis (X) and driven into rotation by a motor/engine or by a biker.

5. A single shock absorber assembly according to any of the previous claims, characterized in that it comprises at least one braking device, for instance a disc brake.

6. A single shock absorber assembly according to the previous claim 5 characterized in that said braking device is mounted on said second shaft parallel to said axis (X) .

7. A single shock absorber assembly according to the previous claim 5 characterized in that said braking device is mounted on said first shaft (31) .

8. A single shock absorber assembly according to any of the previous claims characterized in that said fourth toothed pinion (16) is connected to said second shaft parallel to said axis (X) via a freewheel device, such as, for instance, a ratchet gear.

9. A single shock absorber assembly according to any of the previous claims 1, 2, or 5 characterized in that said central longitudinal element (5) is turnable with respect to the frame of the velocipede, being it capable of rotating about an axis (Z) substantially perpendicular to said axis (X), and is connected to steering devices, by acting onto which a biker can vary the angle of rotation of said central longitudinal element (5) about said axis (Z) .

10. A single shock absorber assembly according to the previous claim 9, characterized in that said steering devices comprise two half-handlebars (17, 18) rotationally coupled with the frame of the vehicle, two sheathed cables (19, 20) each connected at one end to one of said half- handlebars (17, 18) so that rotating a half-handlebar results in stretching its respective cable, a pulley (21) accommodated in the frame and connected to said cables (19, 20) so that whenever a cable is stretched the pulley rotates in one direction whereas whenever the other cable is stretched the pulley rotates in the opposite direction, a rigid rod (22) eccentrically connected to said pulley (21) so that rotating said pulley (21) results in a linear motion of the rod (22), said rod (22) being connected at the opposite end to a support (55) of said central longitudinal element (5) eccentrically mounted with respect to the center of rotation about said axis (Z), so that the rectilinear movement of the rod (22) makes said central longitudinal element (5) rotate about said axis (Z) .

11. A single shock absorber assembly according to the previous claim 9 or 10, characterized in that said central longitudinal element (5) features a housing on the upper side, which is rotationally engaged by a pin projecting from the frame of the velocipede and developing according to an axis (Z) substantially perpendicular to said axis (X) .