Electrically powered vehicle.

DESCRIPTION

The present invention relates to an electric vehicle that in particular, although not exclusively, can be configured as an electric wheelchair for disabled people or people with reduced mobility.

More specifically, an electric vehicle according to the present invention is of the type comprising traction wheels connected to an electrified drive unit and pivoting wheels, in which directional control is managed by means of a joystick or other device interfaced with a control unit that, according to the inputs transmitted by the user, controls the torque transmitted by the drive unit to the traction wheels. The pivoting wheels and the traction wheels are constrained to a chassis on which the seat for the user and the direction control devices are arranged.

US9039018B1 discloses an electric vehicle comprising a frame on which two driving wheels, each connected to a respective electric motor, and two pivoting wheels are mounted. On each side of the frame, a traction wheel and a pivot wheel are both suspended to the same side shaft by coaxial damping attachments arranged along said shaft. Since said shaft is in a central position on the frame, for the assembly of the pivoting wheels it is necessary to make use of corresponding diagonal connecting rods which amplify the torsional stresses on the attachments and on the respective dampers and determine structural and assembly complexities that are not compatible with the current production requirements, also in relation to the fact that the side shafts of the chassis must be sized and configured to withstand the loads transmitted by both the pivoting wheels and the traction wheels.

The main object of the present invention is to provide an electric vehicle, which can be configured for example as an electric wheelchair, equipped with a particularly simple, effective and economical system for damping the shocks transmitted to the chassis by the pivoting wheels.

This result has been achieved in accordance with the present invention by adopting the idea of realizing an electric vehicle having the characteristics indicated in claim 1. Other characteristics of the present invention are the subject of the dependent claims.

Among the advantages offered by the present invention the following are mentioned for example: the mechanical structure of the torsional damping system is simplified, and further benefits arise in terms of production costs and simplification of maintenance operations; the effectiveness of the torsional damping system implies greater comfort for the user; the torsional damping system can be used both on vehicles with rear traction wheels and on vehicles with front or center traction wheels.

These and further advantages and characteristics of the present invention will be more and better understood by any person skilled in the art thanks to the following description and the attached drawings provided by way of example, but not to be considered in a limiting sense, in which:

- Fig. l is a schematic side view of a possible embodiment of an electric wheelchair in accordance with the present invention under normal running conditions.

- Fig.2 is a schematic side view of a possible embodiment of an electric wheelchair in accordance with the present invention in a configuration assumed following a collision which causes the clockwise rotation of the attachment of a pivoting wheel.

- Fig.3 is a schematic side view of a possible embodiment of an electric propulsion wheelchair in accordance with the present invention in a configuration assumed following a collision which causes the anti-clockwise rotation of the attachment of a pivoting wheel.

- Fig.4 is a schematic exploded perspective view of a detail of Fig.1.

- Fig.5 is a further schematic exploded perspective view of a detail of Fig.1.

- Fig.6 represents a schematic transparent view of a detail of Fig.1.

- Fig.7 represents a further embodiment of a vehicle according to the present invention. The examples provided in the following description relate to the application of the present invention to a vehicle configured as a wheelchair for disabled people or people with reduced mobility. However, it is understood that these examples are provided for the purpose of describing possible ways of implementing the present invention. The present invention can equally be applied to vehicles having a different function from the one indicated above, such as for example light vehicles with electric propulsion intended for road traffic or even golf carts, transporting carriages and in all applications in which, more generally, it is possible to implement the invention described and claimed below.

An electrically powered wheelchair which integrates a technical solution according to the present invention is of the type comprising a chassis (1) on which a seat is formed (schematically represented by the dotted rectangle 2 in Fig.1) for the user, two traction wheels (3) and two pivoting wheels (4). The traction wheels (3) are connected to a driving unit formed by two electric motors (M) each of which drives a respective traction wheel. Said electric motors are powered by one or more rechargeable batteries and are controlled by the user by means of a joystick or other suitable directional control device according to a per se known constructive and functional scheme. In the accompanying drawings, the batteries and the joystick are not represented.

Each pivoting wheel (4) is connected to the chassis (1) by means of a fork (5) provided with an upper pin (6) and an attachment (7) comprising a first seat (SI) adapted to receive said pin (6). The fork (5) can also be a single-sided fork.

The upper pin (6) of the fork (5) is free to rotate around its own axis (A6) inside said first seat (SI) of the attachment (7).

The attachment (7) acts as an interface between the fork (5) and the chassis (1), while the fork (5) acts as an interface between the pivoting wheel (4) and the attachment

(7). The latter has a second seat (S2), oriented orthogonally to the first seat (SI), into which a corresponding fixed shaft (8) is inserted, protruding orthogonally from a side of the chassis (1).

Between the fixed shaft (8), protruding from the chassis (1), and an inner wall of said second seat (S2), a damper (9) is positioned which is able to dissipate the energy generated by impacts of the pivoting wheels (4) against possible obstacles. For example, the damper (9) can be made of rubber, plastic material or other polymeric materials.

For example, the damper (9) can consist of a plurality of cylinders (90) made of rubber, plastic material or other polymeric materials arranged along the inner wall of the second seat of the attachment (7) and along the outer surface of the fixed shaft

(8) protruding from the chassis (1).

By way of example, the damper (9), or the elements (90) into which the damper (9) is divided, can be made of an elastomeric material such as for example a polyurethane elastomer with a hardness comprised between 60 and 95 Shore. Such a material is available in Italy under the trade name "Adiprene".

Preferably, said cylinders (90) are positioned in corresponding recesses (Pa) formed on the internal wall of said second seat (S2) and on the external surface of said fixed shaft (8). In the event of a collision of one of the pivoting wheels (4) against an obstacle (for example a low step or a protrusion near a wheelchair access ramp), the consequent clockwise rotation (a) of the connection (7) around the respective fixed shaft (8) is damped. Similarly, the damping effect is also produced in the event of stresses which cause an anti-clockwise rotation of the attachment (7) around the respective fixed shaft (8).

The damper (9) arranged between the fixed shaft (8) and the connection (7), deforms torsionally in the presence of impacts of this kind and dissipates a part of the energy developed during the impact, then returning to its initial configuration.

As shown in the drawings, only the pivot wheel (4) of the respective side of the chassis (1) is mounted on the shaft (8). In other words, on each side of the chassis the shaft (8) only supports the respective pivot wheel (4). Yet in other words, on each side of the frame (1) said shaft (8) is intended to support the respective pivoting wheel (4) and not also the corresponding traction wheel. Therefore, it is possible to realize a configuration in which the axis (A6) is close to the shaft (8), i.e. the aforementioned seats (SI, S2) of the attachment (7) are adjacent to each other.

In the drawings, the reference (30) indicates a pin, orthogonal to a side of the chassis (1), on which the respective traction wheel (3) is suspended. Said pin (30) is spaced from the shaft (8) arranged for the pivoting wheel (4) on the same side of the chassis. This entails evident benefits for the user in terms of comfort despite the constructive simplicity of the system thus realized.

If the damper (9) comprises several elements (for example cylindrical elements 90 as previously described) these are preferably distributed uniformly inside the second seat (S2) of the attachment (7) and along the fixed shaft (8) protruding from the chassis (1).

In the attached drawings, the attachment (7) is a T-shaped body seen from above and the aforementioned seats (SI, S2) are formed inside it. For example, the attachment (7) consists of two tubular bodies (7a, 7b), oriented at right angles to each other, which define said first and second seats. Said tubular bodies (7a, 7b) are integral with each other forming a single body.

The drawings show, for illustrative purposes, a first (82) and a second (83) mounting bearing for the attachment (7) on the shaft (8), an anti-extraction unit (80) per se known and a cap (81) for external closure of the seat (S2) and fixing screws (84) of the cap itself. The drawings also show, for illustrative purposes, a third (86) and a fourth (87) bearing for mounting the pin (6) in the seat (SI) and a cap (88) for closing the top of the seat (SI).

In the example shown in the accompanying drawings, a third seat (S3) is formed on one side of the attachment (7) in which a LED light (70) is mounted.

With reference to the example represented in Fig.7, the forks (5) of the pivoting wheels (4) of the vehicle are connected, by means of the attachment (7) previously described, to two respective extensions (11) of the frame (1) which each have a shaft or pin (8) on which the attachment is mounted. Also in this case, a torsional damper (9) is mounted between the shaft (8) and the attachment (7) capable of elastically damping the rotations of the attachment (7) around the shaft (8) and then returning to its initial configuration when the forces provoking these rotations cease. The damper (9) can be made of several elements, for example cylindrical, as previously described. In the example of Fig.7 the traction wheels (3) are in an intermediate position between the pivoting wheels (4) and two other wheels (40) idle connected to a rear part of the chassis (1) by means of respective arms (41) connected with a hinge (42) with an axis orthogonal to the same chassis in a manner known per se.

From the above description it is evident that a vehicle according to the present invention is an electric vehicle comprising a chassis (1), traction wheels (3) connected to a drive unit (M) and constrained to the chassis (1) by means of respective support pins (30), pivoting wheels (4) also connected to the chassis (1 ), wherein each pivoting wheel (4) is connected to a fixed shaft (8) protruding from a respective side of the chassis (1) by means of an attachment (7) provided with a seat (S2) in which is inserted said shaft (8) so that the attachment (7) can rotate around the shaft (8), wherein a torsional damper (9) is positioned between said seat (S2) and the shaft (8) capable of dampening the rotations of the attachment (7) around the shaft (8), and wherein on each side of the chassis the shaft (8) to which the pivot wheel (4) is connected is spaced from the pin (30) on which the respective traction wheel (3) is connected.

From the above description it is also evident that a vehicle according to the present invention may comprise one or more of the following features even combined with each other: each of said pivoting wheels (4) is connected to the respective attachment (7) by means of a corresponding connecting member. said connecting member is a fork (5). said attachment (7) rotates around the fixed shaft (8) due to an impact of the pivoting wheel (4) against an obstacle.

- the rotation of the attachment (7) around the fixed shaft (8) is clockwise or anticlockwise.

- the torsional damper (9) is made of rubber, plastic material or other polymeric materials or elastomeric material. said torsional damper (9) is divided into a plurality of damping elements, said damping elements are cylinders (90) of rubber, plastic material or other polymeric or elastomeric materials arranged along the internal wall of the second seat (S2) of the attachment (7). said damping elements are housed partly in recesses formed on the fixed shaft (8) and partly in recesses formed on an internal wall of said seat (S2).

- the vehicle is configured as a wheelchair for the disabled persons or people with reduced mobility capabilities.

- the attachment (7) is T-shaped and inside it are formed said seats (SI, S2).

- the attachment (7) is composed of two tubular elements (7 a, 7b), orthogonally oriented in relation to each other, that define said first and second seat and wherein said tubular elements (7a, 7b) are united with each other forming a single body.

In practice, the execution details can in any case vary in an equivalent way as regards the individual elements described and illustrated, without thereby abandoning the idea of the solution adopted and therefore remaining within the limits of the protection granted by the present patent according to the following claims.