Mechanism for holding and turning a wheel

Abstract

The present invention relates to a mechanism (1) for holding and turning a wheel for a device (2) for mounting / removing tyres, comprising at least one hydraulic unit arranged to distribute pressurised oil, an arm (5) that is hinged at one of its ends to a frame (4), set in motion by means of the pressurised oil, and that receives, at its free end, the mechanism (1), which comprises at least one mandrel (10) arranged to hold a wheel and transmission means (11) that make it possible to turn the mandrel (10), characterised in that the transmission means (11) comprise at least one actuator (31) arranged to be fixed to the arm (5) interacting with a transmission member in order to directly drive the mandrel (10), the actuator (31) being of the hydraulic motor type, the hydraulic displacement of which is at least ten times greater than that of the hydraulic unit.

Description

MECHANISM FOR HOLDING AND ROTATING A WHEEL Technical field of the invention

[0001] The present invention relates to the general field of mounting / dismounting tires on vehicles, primarily heavy goods vehicles. More specifically, it relates to a mechanism for holding and rotating a wheel for a tire mounting / dismounting device. State of the art

[0002] We already know of many devices that allow for the mounting / dismounting of tires, as well as their inflation, and that can be permanently installed in garages or in a light utility vehicle for intervention.

[0003] The vast majority of these known tire mounting / dismounting devices typically include at least a frame, an articulated arm at one end of said frame, a holding and rotation mechanism attached to the free end of said arm and arranged to secure and rotate a wheel around a first, substantially horizontal, axis of rotation, and a tool holder equipped with at least one tire mounting / dismounting tool. This tool holder is retractable and can be translated relative to said arm to position said tool in different working positions. Furthermore, said arm and tool holder are movable to position the chuck and the tool in their respective working positions.

[0004] The multiple mobility of these tire mounting / dismounting devices is particularly interesting because it not only allows the operator to retrieve and manipulate the wheel and dismount / remount the tire effortlessly, but also provides very compact tire mounting / dismounting devices once the entire arm-tool holder is folded onto the chassis.

[0005] On these tire mounting / dismounting devices, the holding and rotation mechanism includes a chuck which allows the wheel to be gripped at the rim using expanding jaws, the expansion of which is ensured by a deformable parallelogram whose pivot points are fixed and not removable from the chuck.

[0006] Furthermore, given the rotation of the chuck and the forces involved in mounting / dismounting the tire from the rim, the gripping force exerted by the jaws must be significant and durable.

[0007] Given the efforts involved in removing the tire from the rim and for safety reasons, the chuck must be rotated at a reduced speed, typically less than or equal to 6 rpm.

[0008] For rotating the chuck, conventional transmission systems are used, consisting of an electric or hydraulic motor coupled to a gearbox, such as a worm gear, to slow the rotational speed and multiply the output torque at the chuck. This type of transmission is advantageous because it is compact and offers a high reduction ratio.

[0009] However, it has several drawbacks, namely: it requires good lubrication, good sealing, and high manufacturing precision, as well as significant energy consumption to compensate for its poor efficiency due to friction generated by the sliding between the gear teeth of the reducer. Furthermore, the configuration of this type of transmission system complicates maintenance by requiring the disassembly of numerous components.

[0010] Furthermore, tire mounting / dismounting devices can also be used to support a wheel during a tread regrooving operation when the grooves are no longer deep enough to evacuate water from the road surface, thus extending the tire's lifespan. This regrooving is carried out using a hand-operated power tool to reshape the grooves on the tread.

[0011] During this operation, which is carried out by an operator using a portable power tool, the chuck supporting the wheel must, on the one hand, be periodically repositioned in rotation and, on the other hand, rotate very slowly, in order to allow the operator to easily access the different portions of the tread and work each groove continuously during the rotation of the wheel.

[0012] The aim of the present invention is therefore to propose an alternative to the known mechanism for holding and rotating a wheel for a tire mounting / dismounting device, said mechanism being compact, easy to implement and easy to maintain, while offering much better energy efficiency and allowing other uses for said mechanism.

[0013] According to the invention, a mechanism for holding and rotating a wheel for a tire mounting / dismounting device is therefore proposed, comprising at least one hydraulic unit arranged to distribute pressurized oil, an arm articulated at one end on a chassis, set in motion, at least indirectly, by means of the pressurized oil, and receiving at its free end said mechanism, the latter comprising at least one chuck arranged to hold a wheel and transmission means for rotating the chuck around an axis of rotation, said chuck being of the expanding type and comprising at least a plurality of jaws and an actuator setting said jaws in motion, said mechanism being remarkable in that the transmission means comprise at least one actuator arranged to be fixed on the arm and cooperating with a transmission member to directly drive the chuck,the actuator being of the hydraulic motor type whose hydraulic displacement is at least ten times greater than that of said hydraulic unit.

[0014] Advantageously, the transmission element of the transmission means is of the flexible type and comprises at least: - a drive pulley set in rotation by the actuator around an axis parallel to the axis of rotation of the chuck, - a driven pulley fixed on the end of the chuck, located on the opposite side of the jaws, and rotating around said axis, and - an endless band surrounding the drive and driven pulleys so that the rotation of the drive pulley causes the rotation of the driven pulley, and therefore the rotation of the chuck.

[0015] The actuator control means enabling the expansion of the chuck jaws advantageously pass through the endless belt.

[0016] Advantageously, the endless belt is a synchronous belt or a chain and in that the first and second pulleys are provided with suitable teeth.

[0017] According to another embodiment, the transmission element of the transmission means is of the type with single-stage parallel gear trains or with bevel gears.

[0018] The actuator is advantageously equipped with an adjustable hydraulic flow modulation device.

[0019] According to an advantageous embodiment, the chuck comprises at least: - a base on which the actuator is fixed on the opposite side of the jaws, - a plurality of sleeves each fixed, in a removable manner, on said base, - a plate mounted pivoting at least on each of said sleeves about an axis perpendicular to the axis of rotation of the chuck and on which one of the jaws is mounted pivoting about an axis parallel to the pivot axis of said plate, - a connecting rod mounted pivoting at its ends on each jaw and on the associated sleeve about axes parallel to the pivot axis of said plate respectively, and - a guide roller mounted pivoting on the plate about an axis parallel to the pivot axis of said plate.

[0020] Preferably, the respective pivot axes of the plate, the jaw and the connecting rod are positioned so that their projections onto a perpendicular plane correspond to the vertices of a parallelogram.

[0021] According to an advantageous embodiment, the actuator is advantageously of the cylinder type whose rod is fixed at one of its ends to a piston sliding inside a body and in that it is pivotally mounted on the free end of the arm of the tire mounting / dismounting device around the axis of rotation of the chuck.

[0022] Advantageously, the rod receives a push plate and a pull plate, each extending perpendicularly to the longitudinal axis of said rod and spaced so as to receive between them the guide roller associated with each of the jaws, said guide roller then being able to slide in a direction perpendicular to the longitudinal axis of the rod. Brief description of the figures

[0023] Other advantages and features will become clearer from the following description of an embodiment of the invention, with reference to the attached schematic figures in which:

[0024] is a perspective view of a mechanism for holding and rotating a wheel according to the invention, implemented on a tire mounting / dismounting device shown partially,

[0025] is a perspective view of a mechanism for holding and rotating a partially disassembled wheel,

[0026] is a partial perspective view of the chuck of the mechanism for holding and rotating a wheel of the,

[0027] is a partial exploded perspective view of the chuck of the,

[0028] is a partial exploded cross-sectional view of the chuck, and

[0029] is a perspective view of the actuator of the transmission means equipped with a flow limiter.

[0030] With reference to figures 1 to 6, a mechanism 1 for holding and rotating a wheel according to the invention has been represented in accordance with the invention, put in place on a device 2 for mounting / dismounting tires, said mechanism 1 being arranged to secure and rotate a wheel around a substantially horizontal axis of rotation 3.

[0031] In a known manner, said tire mounting / dismounting device 2 comprises at least a frame 4, an arm 5 articulated at one end to said frame 4 and receiving at its free end said mechanism 1, and a tool holder 6 equipped with at least one tire mounting / dismounting tool, said tool holder 6 being capable of moving relative to said arm 5 to position said tool in the working position, said tire mounting / dismounting device 2 further comprising a hydraulic unit, not shown, integral with the frame 4 arranged to distribute pressurized oil to at least indirectly enable the arm 5 to move in order to position the mechanism 1 and the tool in their respective working positions. As described later, the pressurized oil may also, where applicable, enable the mechanism 1 to rotate, at least indirectly, around said axis of rotation 3.

[0032] The term "at least indirectly" means that pressurized oil enables the movement of elements such as, for example, arm 5 or mechanism 1 through complementary components such as, for example, a motor, an actuator or a cylinder.

[0033] With reference to figures 3 to 5, the mechanism 1 for holding and rotating a wheel according to the invention is attached to the free end of the arm 5 of the tire mounting / dismounting device 2, advantageously attached to a frame 7 articulated on said free end, and includes at least one mandrel 10 arranged to hold a wheel, at the rim level and transmission means 11 allowing the mandrel 10, and consequently the mandrel 10 – wheel assembly, to be rotated around said axis 3 of rotation.

[0034] The chuck 10 is of the expanding type and comprises at least a plurality of jaws 12 and an actuator 13 moving said jaws 12 between a "closed" position in which the jaws 12 are in contact and an "open" position in which the jaws 12 are separated from each other.

[0035] For this purpose, with reference to the, said chuck 10 further advantageously comprises at least: - a base 14 on which said actuator 13 is fixed on the opposite side of the jaws 12, - a plurality of sleeves 15 each fixed, in a removable manner, on said base 14, advantageously by means of screws 16, - a plate 17 pivotally mounted at least on each of said sleeves 15 about an axis 18 perpendicular to the axis 3 of rotation of the chuck 10 and on which one of the jaws 12 is pivotally mounted about an axis 19 parallel to the pivot axis 18 of said plate 17, - a connecting rod 20 pivotally mounted at its ends on each jaw 12 and on the associated sleeve 15 about axes 21, 22 respectively parallel to the pivot axis 18 of said plate 17, and - a guide roller 23 pivotally mounted on the plate 17 around an axis 24 parallel to the pivot axis 18 of said plate 17.

[0036] Advantageously, with reference to the diagram, the respective pivot axes 18, 19, 21, and 22 of the plate 17, the jaw 12, and the connecting rod 20 are positioned so that their projections onto a perpendicular plane correspond to the vertices of a parallelogram. This "deformable parallelogram" configuration prevents the jaws 12 from pivoting and thus keeps the gripping surface of the wheel rim parallel to the axis of rotation 3 of the chuck 10.

[0037] It is clear that, in order to effectively grip the wheel at the rim, the chuck 10 comprises at least three assemblies: sleeve 15 - face 17 - jaw 12 - connecting rod 20, uniformly distributed angularly. However, the chuck 10 may have more than three assemblies: sleeve 15 - face 17 - jaw 12 - connecting rod 20, without departing from the scope of the present invention. Thus, in the embodiment shown in Figures 1 to 4, the chuck 10 comprises four assemblies: sleeve 15 - face 17 - jaw 12 - connecting rod 20. Furthermore, with their specific configuration, each of the assemblies: sleeve 15 - face 17 - jaw 12 - connecting rod 20 can be fully assembled on a workbench and then mounted on the base 14 of the chuck 10, thereby facilitating its maintenance.

[0038] It is clear that the disassembly of the sleeve 15 - plate 17 - jaw 12 - connecting rod 20 assemblies suggests ease of assembly and maintenance, but also the possibility of adapting other types of assemblies in place of the said sleeve 15 - plate 17 - jaw 12 - connecting rod 20 assemblies, in order to adapt the tire mounting / dismounting device 2 to specific uses.

[0039] In addition, the chuck 10 is provided with reinforcement and protection plates 25, each arranged between two sleeves 15. These reinforcement and protection plates 25 allow the internal forces of the chuck 10 to be absorbed by the expansion force and the drive torque of the rim, but also to close the volume between the sleeve 15 - plate 17 - jaw 12 - connecting rod 20 assemblies for greater safety for the operator.

[0040] The actuator 13 is advantageously of the cylinder type in which the rod 26 is fixed at one of its ends to a piston 27 sliding inside a body 28 and can translate between at least one "retracted" position in which the rod 26 is fully retracted into the body 28 and an "extended" position in which the rod 26 is at least partially extended from said body 28. Said actuator 13 may be of the electric or hydraulic type.

[0041] For reasons explained later, the actuator 13 is pivotally mounted on the free end of the arm 5 of the tire mounting / dismounting device 2 around the axis 3 of rotation of the chuck 10, the base 14 of the chuck 10 being fixed on one end of the actuator 13 so that the rotation of the latter causes the rotation of the chuck 10 and, where applicable, of the chuck 10 – wheel assembly.

[0042] According to the embodiment shown in figures 1 and 2, the body 28 of the actuator 13 passes through the frame 7 and is mounted pivotally on the latter around the axis 3 of rotation of the chuck 10, the base 14 of the chuck 10 being then fixed on one of the ends of said body 28.

[0043] Furthermore, the free end of the rod 26 receives a push plate 29 and a pull plate 30, each extending perpendicularly to the longitudinal axis of said rod 26 and being spaced so as to receive between them the guide roller 23 associated with each of the jaws 12, said guide roller 23 being able to slide in a direction perpendicular to the longitudinal axis of the rod 26, the latter being parallel, and advantageously coaxial, to the axis 3 of rotation of the chuck 10. Thus, when the rod 26 moves from the retracted position to its extended position, each guide roller 23 slides in the direction of said rod 26, which has the effect of moving the associated jaw 12 from its "closed" position to its "open" position, and vice versa.

[0044] As described previously, the mechanism 1 for holding and rotating a wheel according to the invention also includes transmission means 11 for rotating the chuck 10. Advantageously, the transmission means 11 include at least one actuator 31 arranged to be fixed on the arm 5, advantageously on the frame 7, and cooperating with a transmission member advantageously of the flexible type such as, for example, a chain-pulley assembly or a belt-pulley assembly, to directly drive the chuck 10, i.e. without any other transmission or power reduction element between the actuator 31 and the transmission member or between the chuck 10 and said transmission member.

[0045] This type of flexible transmission element is interesting because it has the following advantages: - operation with low energy losses, and therefore with better energy efficiency compared to that of a worm gear type transmission, - operation with minimal or no lubrication, - compactness, lightness and quiet operation, and - long service life.

[0046] However, the transmission means 11 may also include a single-stage parallel gear transmission or a bevel gear transmission instead of the flexible transmission element, without departing from the scope of the present invention. However, this type of gear transmission element has the major drawback of requiring significant lubrication.

[0047] Thus, according to the embodiment shown in Figures 1 and 2, the transmission member of the transmission means 11 comprises at least: - a drive pulley 32 rotated by the actuator 31 around an axis 33 parallel to the axis 3 of rotation of the chuck 10, - a driven pulley 34 fixed on the end of the chuck 10, advantageously on the end of the body 28 of the actuator 13, located on the opposite side of the jaws 12, said driven pulley 34 then rotating around the axis 3 of rotation of the chuck 10, and - an endless belt 35 surrounding the drive and driven pulleys 32, 34 so that the rotation of the drive pulley 32 causes the rotation of the driven pulley 34, and therefore the rotation of the chuck 10 and, where applicable, of the chuck 10 – wheel assembly.

[0048] According to the embodiment shown in Figures 1 and 2, the endless belt 35 is advantageously a synchronous belt, and the first and second pulleys 32, 34 are provided with suitable teeth. However, it is understood that the endless belt 35 could also be a chain, without departing from the scope of the present invention.

[0049] It is clear that with this configuration, with the respective axes of rotation 33,3 of the driving and receiving pulleys 32,34 parallel to each other, the transmission means 11 are particularly compact.

[0050] Furthermore, the actuator 31 is advantageously either a hydraulic or electric motor that can be modulated in rotational speed.

[0051] Regarding the characteristics of the actuator 31, it is known that the maximum torque experienced at the chuck 10 – wheel assembly will not exceed 2000 Nm at 6 rpm. This maximum torque corresponds to the resisting torque due to the difficulty of removing the tire, opposing the rotation of the chuck 10 – wheel assembly. Given the overall reduction ratio of the transmission means 11, which is between 160 and 230, the actuator 31 must therefore be of the high-torque type, meaning that the maximum torque at its shaft must be greater than 500 Nm at 19 rpm. This maximum torque value is approximately twelve times higher than the maximum torque at the shaft of the worm gear drive typically used in prior art wheel mounting and rotation mechanisms.

[0052] The speed reduction ratio, mentioned previously, is also an important characteristic of the actuator 31, regardless of the embodiment chosen for the latter. Indeed, since the worm gear transmission has been replaced to improve the efficiency of the transmission means 11, it is necessary to maintain a similar speed reduction ratio, namely a value between 160 and 230.

[0053] Thus, assuming an actuator 31 of the hydraulic motor type, advantageously an orbital internal gear motor, this high value (between 160 and 230) of the speed reduction ratio is obtained thanks to the high ratio between the hydraulic displacement of the actuator 31 and that of the hydraulic unit capable of distributing pressurized oil to the entire device 2 for mounting / dismounting tires, said hydraulic displacement ratio, which acts as a hydraulic speed reducer, being at least equal to 10, that is to say that the hydraulic displacement of the actuator 31 is at least ten times greater than that of the hydraulic unit.

[0054] As is known, the hydraulic unit includes a pump, and the term "displacement of the hydraulic unit" therefore actually refers to the "displacement of said pump".

[0055] Thus, in practice, this high displacement ratio (at least equal to 10) is obtained by a significant difference between the displacement of the pump included in the hydraulic unit and that of the actuator 31. For example, if said pump has a displacement of 5cm³, the actuator 31 will have a displacement of at least greater than or equal to 50 cm³ in order to obtain this reducing effect.

[0056] To enable other uses, such as, for example, regrooving the tread grooves of a tire, the mechanism 1 for holding and rotating a wheel according to the invention must be able to modulate the rotational speed of the chuck 10 – wheel assembly on an ad hoc basis, in order to reduce it even more significantly. For this purpose, the actuator 31 is advantageously equipped with an adjustable hydraulic flow modulation device 36 (see diagram), which allows the rotational speed of the chuck 10 – wheel assembly to be reduced below 2 rpm. This adjustable hydraulic flow modulation device 36 is, for example, a flow limiter, a flow regulator, a proportional valve, or any other device that allows the flow supplied to the hydraulic motor-type actuator 31 to be adjusted.

[0057] Assuming an actuator 31 of the synchronous or asynchronous electric motor type, this high reduction ratio is achieved using a gearbox. For efficiency improvements, this gearbox is advantageously of the strain-wave type, also known as a harmonic gearbox. This type of gearbox also offers the advantages of being compact, quiet, requiring little lubrication, and exhibiting minimal backlash.

[0058] As described above, the mechanism 1 for holding and rotating a wheel according to the invention must be able to modulate the rotational speed of the chuck 10 – wheel assembly on an ad hoc basis, in order to reduce it even more significantly. To this end, the actuator 31, in its electric motor version, is equipped with a potentiometer-type modulation device connected to an electronic controller / variator. The potentiometer can advantageously be installed in a small, remote enclosure, preferably equipped with a magnetic clip, so as to remain readily accessible to the operator.

[0059] It is clear that the ability to switch from a hydraulic actuator 31 to an electric actuator 31 without significant modification of the tire mounting / dismounting device 2 allows the latter to be given industrial modularity depending on the nature of the energy source supplying it.

[0060] The actuator 31 driving the chuck 10 in rotation is, whatever its type, advantageously mounted on a sliding member in order to be able to adjust, if necessary, the tension of the flexible transmission member of the transmission means 11.

[0061] Finally, when the transmission means 11 include a flexible transmission element, the mechanism 1 for holding and rotating a wheel according to the invention is configured so that the control means of the actuator 13 allowing the expansion of the jaws 12 of the chuck 10 pass through the endless belt 35 in order to allow the replacement of the latter easily without needing to disconnect said control means (Cf.), which significantly simplifies the maintenance and servicing of said mechanism 1 for holding and rotating a wheel.

[0062] The mechanism 1 for holding and rotating a wheel according to the invention finds a particular application for a tire mounting / dismounting device mounted on a light utility vehicle to allow rapid intervention outside, but it goes without saying that it can be adapted on a tire mounting / dismounting device permanently installed in a garage or a shop specializing in vehicle maintenance and tire mounting / dismounting.

[0063] Finally, it goes without saying that the examples of mechanisms 1 for holding and rotating a wheel according to the invention which have just been described are only particular illustrations, in no way limiting of the invention.

Claims

Mechanism (1) for holding and rotating a wheel for a tire mounting / dismounting device (2) comprising at least one hydraulic unit arranged to distribute pressurized oil, an arm (5) articulated at one end on a frame (4), set in motion, at least indirectly, by means of the pressurized oil, and receiving at its free end said mechanism (1), the latter comprising at least one chuck (10) arranged to hold a wheel and transmission means (11) for rotating the chuck (10) about an axis (3) of rotation, said chuck (10) being of the expanding type and comprising at least a plurality of jaws (12) and an actuator (13) for moving said jaws (12), said mechanism (1) being characterized in that the transmission means (11) comprise at least one actuator (31) arranged to be fixed on the arm (5) cooperating with a transmission member to directly drive the chuck (10),the actuator (31) being of the hydraulic motor type whose hydraulic displacement is at least ten times greater than that of said hydraulic unit. Mechanism (1) according to claim 1 characterized in that the transmission member of the transmission means (11) is of the flexible type and comprises at least: - a drive pulley (32) set in rotation by the actuator (31) about an axis (33) parallel to the axis (3) of rotation of the chuck (10), - a driven pulley (34) fixed on the end of the chuck (10), located on the opposite side of the jaws (12), and rotating about said axis (3), and - an endless belt (35) surrounding the drive and driven pulleys (32,34) so ​​that the rotation of the drive pulley (32) causes the rotation of the driven pulley (34), and therefore the rotation of the chuck (10). Mechanism (1) according to claim 2 characterized in that the control means of the actuator (13) allowing the expansion of the jaws (12) of the chuck (10) pass through the endless belt (35). Mechanism (1) according to any one of claims 2 or 3 characterized in that the endless belt (35) is a synchronous belt or a chain and in that the first and second pulleys (32,34) are provided with suitable teeth. Mechanism (1) according to claim 1 characterized in that the transmission member of the transmission means (11) is of the single-stage parallel gear train type or of the bevel gear type. Mechanism (1) according to any one of claims 1 to 5 characterized in that the actuator (31) is equipped with an adjustable hydraulic flow modulation element (36). Mechanism (1) according to any one of claims 1 to 6 characterized in that the chuck (10) comprises at least: - a base (14) on which the actuator (13) is fixed on the opposite side of the jaws (12), - a plurality of sleeves (15) each fixed, in a detachable manner, on said base (14), - a plate (17) pivotally mounted at least on each of said sleeves (15) about an axis (18) perpendicular to the axis (3) of rotation of the chuck (10) and on which one of the jaws (12) is pivotally mounted about an axis (19) parallel to the axis (18) of pivoting of said plate (17), - a connecting rod (20) pivotally mounted at its ends on each jaw (12) and on the associated sleeve (15) about respectively the axes (21, 22) parallel to the axis (18) of pivoting of said plate (17), and- a guide roller (23) mounted pivoting on the plate (17) around an axis (24) parallel to the pivot axis (18) of said plate (17). Mechanism (1) according to claim 7 characterized in that the respective pivot axes (18,19,21,22) of the plate (17), the jaw (12) and the connecting rod (20) are positioned so that their projections onto a perpendicular plane correspond to the vertices of a parallelogram. Mechanism (1) according to any one of claims 1 to 8 characterized in that the actuator (13) is advantageously of the cylinder type whose rod (26) is fixed at one of its ends to a piston (27) sliding inside a body (28) and in that it is pivotally mounted on the free end of the arm (5) of the device (2) for mounting / dismounting tires around the axis (3) of rotation of the chuck (10). Mechanism (1) according to claims 7 and 9 characterized in that the rod (26) receives a push plate (29) and a pull plate (30) each extending perpendicularly to the longitudinal axis of said rod (26) and being spaced so as to receive between them the guide roller (23) associated with each of the jaws (12), said guide roller (23) then being able to slide in a direction perpendicular to the longitudinal axis of the rod (26).

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