MOBILE TRANSPORT DEVICE FOR A CHARGING SYSTEM ALLOWING THE CHARGING / RECHARGE OF ELECTRICAL ENERGY STORAGE DEVICES FOR A VEHICLE INCLUDING AN ELECTRIC MOTOR
The mobile device addresses the challenge of moving heavy objects across obstacles and slopes by using a chassis with oscillating members and adaptable wheel configurations, ensuring stable and efficient transport.
Patent Information
- Application Number
- FR2021000632
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-01-22
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2041-01-22
AI Technical Summary
Existing mobile devices are unable to efficiently move heavy objects (200-500 kg) across obstacles and sloping ground while maintaining stability and efficiency, particularly in confined environments like parking areas, due to limitations in load-bearing capacity and obstacle clearance.
A mobile device with a chassis, oscillating member, and a combination of wheels and casters that allow for adaptable movement, featuring independent lateral arms and differential wheel positioning to maintain contact with the ground over obstacles, ensuring stability and load distribution.
The device effectively navigates obstacles and slopes, maintaining stability and load distribution, enabling safe transport of heavy objects in complex environments.
Smart Images
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Abstract
Description
Title of the invention: MOBILE DEVICE FOR TRANSPORTING A CHARGING SYSTEM TO CHARGE / RECHARGE ELECTRICAL ENERGY STORAGE DEVICES FOR A VEHICLE INCLUDING AN ELECTRIC MOTOR - SCOPE OF THE INVENTION
[0001] The present invention relates to the technical field of omnidirectional mobile devices, that is to say devices that can move or ensure the movement of an object in all directions.
[0002] Such a mobile device can for example be used to transport a charging system for charging / recharging electrical energy storage means of a vehicle comprising an electric motor.
[0003] To achieve this, the charging system is mounted on the mobile device. This results in a "charging robot" which has the ability to move in a confined space environment, such as a parking area composed of parking structures and / or on-street parking.
[0004] For the purposes of this invention, "parking facilities" means parking (temporary or permanent) organized into delimited spaces within an enclosed area with controlled access, such as an above-ground, underground, or surface parking lot. "On-street parking" means parking (temporary or permanent) organized into spaces—delimited or not—in an open area, whether paid or free.
[0005] The association of the mobile device according to the invention with a charging system therefore allows a fully automatic unit which moves along programmed routes and stops to perform the planned charging / recharging operations.
[0006] BACKGROUND OF THE INVENTION
[0007] For many applications, there is a need for mobile devices that allow heavy objects to be moved in all directions.
[0008] Such mobile devices must be able to move in an environment that is sometimes cramped and includes obstacles on the ground such as a speed bump of the "sleeping bar" type, a curb, a reflective bollard, an electrical cable, etc.
[0009] These mobile devices must also be adapted to move on prepared ground having a more or less gentle / steep slope (i.e. having a more or less high degree of inclination).
[0010] Among the fields of application, we can mention the movement of a charging system of electrical energy storage means of an electric motor vehicle, for example on a parking area composed of parking structures and / or on-street parking.
[0011] For such an application, "all-terrain" type modes of locomotion (on tracks or on legs) are not suitable, as they are unnecessarily complex and expensive compared to mobile devices using wheels.
[0012] A spherical wheel for moving heavy loads in any direction is known from document WO 87 / 06536. The large diameter of the sphere increases its load-bearing capacity and its ability to overcome obstacles. However, this mobile spherical wheel only has a support function, is not motorized, and therefore cannot be used as such to move a charging system for electrical energy storage devices.
[0013] US patent 3,746,112 describes a wheel for an autonomous land vehicle, controlled to rotate in a fixed direction. This wheel comprises a central portion mounted on a rotating axle and a series of rollers, free to rotate, distributed around its circumference such that the axis of the rollers is positioned obliquely with respect to the axis of the central portion. However, as with all the aforementioned wheels, the small diameter of the rollers considerably limits the vehicle's ability to bear a load and to overcome small obstacles.
[0014] One object of the present invention is to provide a device to remedy the aforementioned drawbacks.
[0015] In particular, an object of the present invention is to provide a robust and reliable omnidirectional mobile device capable of moving a heavy object (between 200 kg and 500 kg) and crossing small obstacles placed on possibly sloping ground.
[0016] BRIEF DESCRIPTION OF THE INVENTION
[0017] To this end, the invention proposes a mobile device for moving a heavy object, the device comprising: • a chassis including: • a base extending along a longitudinal axis L-L' defining a rear region, a front region and a central region between the rear and front regions, and • a pair of feet fixed to the base, each foot being mounted on a respective lateral edge of the base at the rear region, • at least two wheels and four casters arranged per triplet, the wheel and two casters of each triplet being aligned along a respective longitudinal edge of the base, the first caster of each triplet being mounted at the free end of a respective foot, • remarkable in that the mobile device further comprises an oscillating member mounted pivotally on the chassis about a pivot axis Piv perpendicular to the longitudinal axis L-L' of the base, the oscillating member including first and second lateral arms each mounted on a respective lateral edge of the base, a wheel and a second roller of each triplet being mounted aligned on a respective lateral arm such that the wheel extends at the level of the central region and the second roller extends at the level of the front region, the oscillating member being capable of moving in rotation about the pivot axis Piv between: • a first extreme position in which the second caster associated with a lateral arm is closer to the base than the wheel associated with the arm, and • a second extreme position in which the wheel associated with the arm is closer to the base than the second wheel associated with the arm.
[0018] Preferred but not limiting aspects of the mobile device according to the invention are as follows: • for each triplet, the first and second wheels can be free-spinning wheels and the third wheel can be a drive wheel; • each free-spinning wheel may include a circular bearing rim and a band extending around the bearing rim; • the band of the first roller of each triplet may be made of a material having a hardness greater than 60 shore A, preferably greater than 80 shore A and even more preferably greater than or equal to 90 shore A; • the band of the second roller of each triplet may be made of a material having a hardness of less than 70 shore A, preferably less than or equal to 60 shore A, and even more preferably less than or equal to 50 shore A; • each free-spinning wheel can be pivoted around a vertical pivot axis A-A' orthogonal to a rotation axis of the circular carrier rim, the rotation axis of the circular carrier rim being offset with respect to the vertical pivot axis A-A'; • The lateral arms of the oscillating member can be independent, so that: • The rotational movement of the first lateral arm around the pivot axis Piv does not cause the rotational movement of the second lateral arm around the pivot axis Piv. • the rotational movement of the second lateral arm around the pivot axis Piv does not cause the rotational movement of the first lateral arm around the pivot axis Piv; • each lateral arm may include a front branch extending towards the front region and a central branch extending towards the central region, the front and central branches being fixed together and being able to pivot around the pivot axis Piv, the wheel being mounted on the free end of the central branch and the second wheel being mounted on the free end of the front branch; • each lateral arm can be inscribed in a triangle, the first vertex of the triangle being mounted pivoting on the base around the pivot axis Piv, and the wheel and the second caster being connected to the lateral arm at the level of the other two vertices of the triangle; • The device may further include a pair of return springs, each spring being associated with a respective lateral arm, and for each spring: • one end of the spring being pivotally mounted on a lateral edge of the base in the rear region, and • the other end of the spring being pivotally mounted to its associated lateral arm in the central region.
[0019] The invention also relates to a system for charging / recharging electrical energy storage means for a vehicle comprising an electric motor, the system comprising: • accommodation, • an electrical energy storage system contained within the dwelling, • an interface element to allow the transfer of electrical energy between the charging / recharging system and the vehicle, and • a controller to manage the transfer of electrical energy between the charging / recharging system and the vehicle, • remarkable in that it also includes a mobile device as described above. Brief description of the drawings
[0020] Other advantages and features of the mobile device according to the invention will become clearer from the following description of several embodiments, given by way of non-limiting examples, based on the accompanying drawings in which:
[0021] [Fig-1] is a schematic perspective representation of the mobile device according to the invention,
[0022] [Fig.2] is a schematic representation of a free-spinning roulette wheel of the device according to the invention,
[0023] [Fig.3] is a schematic side view representation of the mobile device illustrated in [Fig.1],
[0024] [Fig.4] is a first schematic representation of the kinematics of movement of the mobile device illustrated in [Fig.1],
[0025] [Fig.5] is a second schematic representation of the kinematics of movement of the mobile device illustrated in [Fig.1],
[0026] [Fig.6] is a third schematic representation of the kinematics of movement of the mobile device illustrated in [Fig.1]. DETAILED DESCRIPTION OF THE INVENTION
[0027] We will now describe different embodiments of the invention with reference to the figures. In these different figures, equivalent elements are designated by the same numerical reference.
[0028] 1. _ General principle
[0029] With reference to [Fig. 1], the mobile device comprises: • a chassis 1 consisting of a parallelepiped-shaped base 11, a pair of feet 12, and a pair of free-spinning casters 13, each free-spinning caster 13 being mounted on the free end of a respective foot 12, • a pivoting oscillating member 2 mounted pivotally on the chassis 1, the oscillating member 2 including a pair of arms 21, two drive wheels 22 and two idler wheels 23 mounted in pairs on each arm 21, so that each arm is associated with a respective drive wheel 22 and idler wheel 23.
[0030] Thus, the moving device comprises four casters and two wheels aligned in a triplet, each triplet—composed of one wheel and two casters—extending along a respective longitudinal edge of the moving device. For each arm 21 of the oscillating member 2, the drive wheel 22 and the associated idler wheel 23 are mounted so that their axes of rotation extend substantially in a plane P.
[0031] The mobile device also includes a return and damping system 3 connected between the chassis 1 and the oscillating member 2.
[0032] Advantageously, each arm 21 of the oscillating member 2 is capable of rotating about a pivot axis Piv parallel to the plane P between: • a first extreme position in which the idler wheel 23 associated with the arm 21 is closer to the base 11 than the drive wheel 22 associated with the arm 21 (see [Fig. 4]), and • a second extreme position in which the drive wheel 22 associated with the arm 21 is closer to the base 11 than the idler wheel 23 associated with the arm 21 (cf. [Fig.5]).
[0033] The combination of a chassis 1 with two casters 21 and an oscillating member 2 with four casters / wheels 22, 23 allows the mobile device to be adapted to crossing obstacles 4, even when moving a heavy object.
[0034] Indeed, the possibility of rotation of the oscillating member 2 allows the mobile device to rest on four casters / wheels (i.e. four casters; or two casters and two wheels), even when crossing an obstacle, which increases its stability.
[0035] 2. Device elements
[0036] 2.1. Chassis
[0037] With reference to [Fig. 1], the chassis 1 includes a substantially flat base 11 intended to receive the heavy object to be moved. The base 11 can be of different shapes depending on the type of object to be moved. The base 11 consists, for example, of a frame composed of two longitudinal profiles and two transverse profiles. These profiles can have an L-shaped, U-shaped, H-shaped, or even square, circular, or rectangular cross-section.
[0038] In the embodiment illustrated in [Fig. 1], the base 11 has a rectangular shape. It is designed to receive an electrical charging system comprising a parallelepiped-shaped housing. The charging system is intended to be bolted onto the base 11 to secure it to the mobile device. This results in a completely autonomous charging / recharging unit capable of moving within a parking area to charge / recharge the electrical energy storage devices of electric motor vehicles.
[0039] Of course, the reader will have understood that the base 11 can have other shapes depending on the intended application and / or the type of heavy object to be moved.
[0040] The chassis 1 also includes two feet 12 arranged at one of the longitudinal ends – referred to as the “rear end” – of the chassis 1. Each foot is fixed to the base 11 at a respective corner (junction area between a longitudinal profile and a transverse profile of the base) of this rear end, and extends downwards (i.e., in a direction opposite to the face of the base 11 suitable for receiving the electrical charging system). In the embodiment illustrated in Figures 1 to 5, each foot 12 extends perpendicularly to the plane of the base 11 along a respective longitudinal axis. This helps to limit the forces applied by the weight of the heavy object at the junction between the base and the foot. However, for certain applications, the angle between Each foot and the base can be less than or greater than 90°. In this case, the frame 1 can include reinforcing bars (not shown) between the base 11 and each foot 12 to limit the forces applied by the weight of the heavy object on the base / foot junction.
[0041] The chassis 1 also includes two idler casters 13 (i.e., which do not transmit power). These casters will be referred to as "rear idler casters" hereafter. Advantageously, the rear idler casters 13 are band casters. More precisely, and with reference to [Fig. 2], each rear idler caster 13 comprises a circular load-bearing rim 1311 and a band 1312 extending around the rim 1311. The rim 1311 is rotatably mounted around a hub 132, disposed at its center, to which the rim 1311 is attached by spokes or a flange, either solid or perforated. The only function of the rear idler casters 13 is to guide and support the heavy object mounted on the base 11. The use of band casters allows the weight of the heavy object to be distributed along a line of contact between the caster and the ground 4.This limits the risk of damage to the floor surface 4, particularly compared to the use of spherical casters which induce point contact with the floor.
[0042] Advantageously, the band 1312 of each rear idler wheel 13 can be made of a material having a hardness greater than 60 shore A, preferably greater than 80 shore A, and even more preferably greater than or equal to 90 shore A. This makes it possible to limit the risks of deformation of the band when crossing an obstacle due to the weight of the heavy object being transported.
[0043] Each rear idler wheel 13 is mounted on the free end of a respective foot 12. Each rear idler wheel 13 is pivotable about a vertical pivot axis A-A' substantially orthogonal to the rotation axis 132 of the rim 1311. More specifically, each rear idler wheel 13 comprises a support bracket 133 including at least one side flange 1331, the lower end of which carries the rim 1311. This support bracket 133 is pivotally mounted about the axis A-A' coaxial with the longitudinal axis of the foot 12. Preferably, each rear idler wheel 13 is eccentric, i.e., an idler wheel in which the rotation axis 132 of the rim 1311 is offset relative to the vertical pivot axis A-A'. This facilitates the rotation of the mobile device.
[0044] 2.2. Oscillating element
[0045] The oscillating member 2 comprises first and second lateral arms 21 arranged along a respective longitudinal edge of the chassis. Each lateral arm 21 is fixed to the base 11 by means of a pivot joint Piv located on a respective longitudinal profile of the base 11.
[0046] The oscillating member 2 also includes two wheels 22 and two rollers 23 arranged in pairs aligned on each arm 21.
[0047] 2.2.1. Side arms
[0048] The lateral arms 21 are independent so that the rotational movement of the first (respectively second) lateral arm around its associated pivot axis Piv does not cause the rotational movement of the second (respectively first) lateral arm around its associated pivot axis Piv. This ensures that the wheel and caster of the second (respectively first) lateral arm remain in contact with the ground when the wheel and caster of the first (respectively second) lateral arm pass over a point obstacle such as a reflective marker. This also limits the risk of the device tipping over when the heavy object is very tall (i.e., taller than the length of the mobile device).
[0049] Each lateral arm 21 comprises a wheel and a roller aligned. In the embodiment illustrated in [Fig. 1], each lateral arm 21 comprises a first branch - called the "front branch" - and a second branch - called the "central branch" - which are coplanar and fixed.
[0050] The free end of each arm comprises a respective wheel / roller. In particular: • Two drive wheels 22 are mounted on the central arms, and • Two idler wheels 23 are mounted on the front arms.
[0051] The oscillating member 2 is fixed to the chassis so that the idler wheels 23 extend at the other of the longitudinal ends - called the "front end" - of the chassis 1. In the following, the idler wheels 23 of the oscillating member 2 will be referred to as "front idler wheels".
[0052] Each arm 21 is arranged so that the axes of rotation of the drive wheels extend equidistant from the front and rear ends of the chassis. Hereafter, the drive wheels of the oscillating member will be referred to as "central drive wheels".
[0053] This particular arrangement of the rear idler wheels 21, the central drive wheels 22, and the front idler wheels 23 allows the weight of the heavy object to be distributed evenly along the entire length of the mobile device. Furthermore, the fact that the drive wheels are positioned in a central region helps to limit the risk of slippage when the mobile device is crossing an obstacle.
[0054] 2.2.2. Free-rolling casters and drive wheels
[0055] The front idler wheels 23 are of the same type as the rear idler wheels 13. They consist of belt rollers having: • a mobile device guidance function and • a function to support the heavy object mounted on the base.
[0056] Each front idler wheel 23 has a rim with a band that pivots about a vertical pivot axis substantially orthogonal to the axis of rotation of the rim with a band.
[0057] Preferably, each free-spinning wheel 23 is an eccentric wheel, that is, a free-spinning wheel in which the axis of rotation of the rim is offset relative to the vertical pivot axis. This makes it easier to turn the mobile device around itself.
[0058] Advantageously, the band of each front idler wheel 23 can be made of a material having a hardness of less than 70 shore A, preferably less than or equal to 60 shore A, and even more preferably less than or equal to 50 shore A. This makes it possible to limit the risks of deformation of the band when crossing an obstacle due to the weight of the heavy object being transported.
[0059] The drive wheels 22 are connected to suitable drive means such as one (or more) electric motor(s). More specifically, the drive wheels 22 receive power from the motor(s) to enable the mobile device to move.
[0060] The reader will appreciate that the drive means can be integrated into each drive wheel 22 to limit the size of the mobile device. In particular, in the variant illustrated in [Fig. 1], a respective electric motor is integrated into the hub of each drive wheel 22.
[0061] Similarly, the control and power electronics, sensors, and batteries can be integrated into each drive wheel 22.
[0062] The axes of rotation of the drive wheels 22 are collinear. This arrangement of the two drive wheels allows the mobile device to pivot. More precisely, by decreasing the angular velocity of rotation of one drive wheel 22 relative to the other drive wheel 22, it is possible to change the direction of movement of the mobile device. Similarly, by reversing the direction of rotation of one drive wheel 22 relative to the other, it is possible to rotate the mobile device on its own axis.
[0063] 2.3. Return and damping system
[0064] The return and damping system 3 consists of at least two springs 3, each associated with a respective lateral arm 21. In particular, a first end 31 of each spring is pivotally mounted (about an axis of rotation parallel to the pivot axis Piv) on a respective lateral arm 21, and a second end 32 of each spring is pivotally mounted (about an axis of rotation parallel to the pivot axis Piv) on the base 11.
[0065] Each spring is adapted to compress or stretch depending on the inclination of the chassis 1 relative to its associated lateral arm 21.
[0066] Each spring has a stiffness constant adapted to the weight of the heavy object to be transported. For example, the stiffness constant may be 6.69 N / mm (for 400 kg on the chassis).
[0067] Each spring is positioned between a rear idler wheel and a central drive wheel. More precisely, for each spring: • the attachment area of the first end 31 of the spring is closer to the rear end than to the front end of the chassis, and • the fixing area of the second end 32 of the spring is closer to the central drive wheel than to the front idler wheel.
[0068] Each spring is mounted on the moving device so as to be compressed when the axes of rotation of the casters and wheels of the device extend in a single plane (for example, horizontally as illustrated in [Fig. 3]). This positioning of the spring and its "compressed" mounting ensure that the central drive wheel 22 of the associated lateral arm 21 makes contact with the ground.
[0069] Advantageously, the return and damping system 3 may also include a pair of shock absorbers, each associated with a respective spring. These shock absorbers dampen the abrupt movements of the springs. In particular, they limit the "pitching" of the moving device when crossing an obstacle.
[0070] Alternatively, the return and damping system 3 may consist of an active suspension.
[0071] 3. Operating principle
[0072] We will now describe the operating principle of the mobile device with reference to figures 4 to 6.
[0073] With reference to [Fig. 4], when the mobile device encounters an obstacle, the front idler wheels 23 come into contact with the obstacle. The flexibility of the wheel bands 1312 cushions the impact of this encounter.
[0074] The drive wheels 22 propel the moving device so that the front idler wheels 23 mount the obstacle. This causes the oscillating member 2 to rotate relative to the chassis 1 in a counterclockwise direction. Each lateral arm 21 pivots about its pivot axis Piv and moves to the first extreme position. The weight of the heavy object is then primarily supported by the rear idler wheels 13. As the springs are compressed, these apply a thrust force to their respective arms 21, tending to press the drive wheels 22 against the ground 4.
[0075] When the pivot axes Piv pass the top of the obstacle, the oscillating member 2 pivots in the retrograde direction. Each lateral arm 21 pivots around its pivot axis Piv and moves to the second extreme position. The weight of the heavy object is then mainly supported by the drive wheels 22. Under the effect of the weight of the heavy object, the springs compress until they reach their maximum compression ratio. In reaction to this compression, the springs apply a thrust force on their respective arms, tending to press the drive wheels 22 against the ground.
[0076] When the drive wheels 22 have passed the top of the obstacle and until all the wheels 22 and casters 23 of the oscillating member 2 have passed over the obstacle, the oscillating member 2 pivots relative to the chassis 1 in a counterclockwise direction. The weight of the heavy object is then primarily supported by the oscillating member 2. With the rear idler casters 13 still on the obstacle, the springs extend until they reach their maximum tension. The weight of the heavy object ensures that the drive wheels 22 remain in contact with the ground.
[0077] When the rear idler wheels 13 have passed the top of the obstacle and until they have passed the obstacle, the oscillating member 2 pivots relative to the chassis 1 in the retrograde direction until the axles of all the wheels 22 and the casters 13, 23 are in contact with the ground 4.
[0078] 4. Conclusions
[0079] The mobile device described above allows the safe transport of heavy objects, even in the presence of obstacles.
[0080] The reader will have understood that many modifications can be made to the invention described above without materially departing from the new teachings and advantages described here.
[0081] For example, in the embodiments described above, each foot was fixedly mounted on the base.
[0082] In other embodiments, each foot can be mounted pivoting on the base around a pivot axis parallel to the pivot axis Piv of the moving member.
[0083] In this case, a return spring is associated with each foot. This return spring allows the associated foot to be maintained in an equilibrium position substantially perpendicular to the base when no lateral force (i.e., parallel to the plane of the base) is applied to the foot. Such a lateral force is applied to the foot when the device crosses an obstacle.
[0084] When crossing an obstacle, under the effect of a lateral force parallel to the direction of movement of the device, each foot moves in rotation by a few degrees, which causes a compression of the return spring.
[0085] This facilitates the operation of crossing the obstacle by limiting the risk of the heavy object carried by the device tipping over. Indeed, the presence of a pivot joint at the junction between the foot and the base makes it possible to reduce the angle of inclination of the heavy object when crossing an obstacle.
[0086] As soon as the lateral force is no longer applied, the return spring brings its associated foot back into its equilibrium position.
Claims
Demands
1. A mobile device for transporting a charging system for charging / recharging electrical energy storage devices of a vehicle comprising an electric motor, the device comprising: • a chassis (1) including: • a base (11) extending along a longitudinal axis (L-L') defining a rear region, a front region and a central region between the rear and front regions, and • a pair of feet (12) fixed to the base (11), each foot (12) being mounted on a respective lateral edge of the base (11) at the rear region, • at least two wheels and four casters (13, 22, 23) arranged per triplet, the wheel and the two casters of each triplet being aligned along a respective longitudinal edge of the base (11), a first caster (13) of each triplet being mounted at the free end of a respective foot (12), • an oscillating member (2) pivotally mounted on the chassis (1) about a pivot axis (Piv) perpendicular to the longitudinal axis (L-L') of the base (11), the oscillating member (2) comprising first and second lateral arms (21) each mounted on a respective lateral edge of the base (11), a wheel (22) and a second roller (23) of each triplet being mounted aligned on a respective lateral arm (21) such that the wheel (22) extends at the central region and the second roller (23) extends at the front region, the oscillating member (2) being capable of rotating about the pivot axis (Piv) between: • a first extreme position in which the second wheel (23) associated with a lateral arm (21) is closer to the base (11) than the wheel (22) associated with the arm (21), and • a second extreme position in which the wheel (22) associated with the arm (21) is closer to the base (11) than the second wheel (23) associated with the arm (21) characterized in that the mobile device further comprises a return and damping system (3) including: • at least two springs each associated with a respective lateral arm (21), and • a pair of dampers each associated with a respective spring.
2. Mobile device according to claim 1, wherein for each triplet, the first and second wheels (13, 23) are idle wheels and the wheel (22) is a drive wheel.
3. Mobile device according to claim 2, wherein each idler wheel (13, 23) comprises a circular carrier rim (1311) and a band (1312) extending around the carrier rim (1311).
4. Mobile device according to claim 3, wherein the band (1312) of the first roller (13) of each triplet is made of a material having a hardness greater than 60 shore A, preferably greater than 80 shore A and even more preferably greater than or equal to 90 shore A.
5. Mobile device according to any one of claims 3 or 4, wherein the band (1312) of the second roller (23) of each triplet is made of a material having a hardness of less than 70 shore A, preferably less than or equal to 60 shore A, and even more preferably less than or equal to 50 shore A.
6. Mobile device according to any one of claims 3 to 5, wherein each idler wheel (13, 23) is pivotable about a vertical pivot axis (A-A') orthogonal to a rotation axis (132) of the circular carrier rim (1311), the rotation axis (132) of the circular carrier rim (1311) being offset with respect to the vertical pivot axis (A-A').
7. A movable device according to any one of claims 1 to 6, wherein the lateral arms (21) of the oscillating member (2) are independent, such that: • The rotational movement of the first lateral arm around the pivot axis (Piv) does not cause the rotational movement of the second lateral arm around the pivot axis (Piv), • The rotational movement of the second lateral arm around the pivot axis (Piv) does not cause the rotational movement of the first lateral arm around the pivot axis (Piv).
8. A mobile device according to any one of claims 1 to 7, wherein each lateral arm (21) comprises a front arm extending towards the front region and a central arm extending towards the central region, the front and central arms being fixed together and being able to pivot about the pivot axis (Rv), the wheel (22) being mounted on the free end of the central arm and the second wheel (23) being mounted on the free end of the front arm.
9. Mobile device according to any one of claims 1 to 8, wherein each lateral arm (21) is inscribed in a triangle, a first vertex of the triangle being pivotally mounted on the base (11) about the pivot axis (Piv), and the wheel (22) and the second wheel (23) being connected to the lateral arm (21) at the level of the other two vertices of the triangle.
10. A mobile device according to any one of claims 1 to 8, wherein each spring of the return and damping system is associated with a respective lateral arm (21), and for each spring: • one end (31) of the spring is pivotally mounted on a lateral edge of the base (11) in the rear region, and • the other end (32) of the spring is pivotally mounted to its associated lateral arm (21) in the central region.