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1. WO2014154617 - SUPPORT DEVICE APPLIED TO A WHEEL WITH TIRE FOR MEANS FOR MEASURING THE ALIGNMENT OF THE WHEEL

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]
"SUPPORT DEVICE APPLIED TO A WHEEL WITH TIRE FOR MEANS FOR MEASURING THE ALIGNMENT OF THE WHEEL"

DESCRIPTION TECHNICAL FIELD

The present invention relates to the field of instruments for measuring the alignment of the wheels of a vehicle and more in particular relates to a support device applied to a wheel with tire for means for measuring the alignment of the wheel.

State of the art

As is known, some types of instruments for measuring the alignment of wheels are provided with a reference associated with each wheel, which contributes to unequivocally determining the position of the wheel in the space. This reference is "read" by an electronic system which, based on the spatial position detected, in combination with other parameters detected and set, enables alignment of the wheel to be calculated.

A crucial aspect is represented by the manner used to associate this reference with the wheel. For example, some devices enable the reference to be fixed integrally with the rim of the wheel, in a position coaxial to the rotation axis thereof.

Instead, in other devices the detection means can be supported without being fixed integrally to the wheel, simply by hanging them on the tire. A device of this type is disclosed, for example, in DE102006026513. In practice, this device comprises a central part on which there is provided a reference measuring column, carrying a laser source, to be positioned on a plane orthogonal to the axis of the wheel, in proximity thereto. From this central part there extend two opposed rods, which carry at the ends thereof two bodies for abutment with the rim or with the outer side of the tire. Also extending from the central part is a third arm, orthogonal to the first two, which also carries a body for abutment against the wheel and which is substantially vertical when the device is associated with the wheel (and therefore the other two rods, lower, are horizontal). At the end of this third rod, or at the end of a rod parallel thereto, there is provided a cantilevered plate with teeth that rests against the upper part of the tread of the tire: in practice the device is hung on the tire by means of the plate. This plate for hanging on the tire can be translated vertically to find the correct positioning of the device, but, after the desired position has been found, this is blocked and the whole device becomes a rigid body.

The center of gravity of the device is such that the central part with the two lower rods tends to adhere to the wheel through gravity. The plate, elastically loaded, also pushes the third rod toward the wheel, in order to implement the contact with all three abutment bodies, so as to ensure correct spatial reference. The contact points with the wheel are therefore four: the three abutment bodies and the plate.

The three rods are rigidly connected to the central part and cannot move when the device is installed on the wheel. As stated above, once the device has been hung on the tire, it becomes a rigid body. Therefore, inaccuracies due to the positioning of the bracket on the tread result in the device only touching in three points (one of which is necessarily the bracket), and one abutment body being at a slight distance (even though this is not visible to the naked eye of the operator), and consequently the spatial accuracy of the measurement reference may be inaccurate. Moreover, even if the device is positioned optimally before blocking the plate, it is possible for the position of the device to vary during blocking of the plate or also after blocking, for example due to accidental impacts. In this case, the plate must be released, all the parts must be repositioned and the plate must be blocked again, with the evident loss of time that this involves.

A similar device is shown in the patent GB2176618. Also in this case there is a body for hanging the device on the tire which can translate vertically to find the correct positioning of the device; after the desired position has been found, the plate is blocked and the whole device becomes a rigid body, and consequently the same problems of inaccuracy as in the previous case are encountered.

Object and summary of the invention

The main object of the present invention is to produce a support device

applied to a wheel with tire for means for measuring the alignment of the wheel that enables a particularly accurate measuring system to be obtained.

Another important object of the present invention is to produce a support device applied to a wheel with tire for means for measuring the alignment of the wheel that is easy to associate with the wheel.

A further important object of the present invention is to produce a support device applied to a wheel with tire for means for measuring the alignment of the wheel that is quick to associate with the wheel.

One more important object of the present invention is that of producing a support device applied to a wheel with tire for means for measuring the alignment of the wheel that is of simple construction.

These and other objects, which will be more apparent below, are achieved with a support device applied to a wheel with tire for means for measuring the alignment of the wheel as described in claim 1 below.

According to the main aspect, the support device according to the invention comprises an abutment structure with the wheel and an apparatus for gripping, or hanging on, the upper part of the tread of the tire of the wheel ; this apparatus is constrained to at least part of the abutment structure along a main axis running from above to below, when the device is applied to the wheel. The peculiarity of the device consists in an axial pivotal constraint about the main axis, adapted to constrain, in a pivoting manner, the gripping apparatus to said at least part of the abutment structure, so that this can rotate freely about this axis and therefore with respect to the gripping apparatus when the device is hung on the tire. According to this aspect, the abutment structure preferably comprises at least two abutment areas with the outer side of the wheel (and preferably against side of the tire) so that, when the device is applied to the wheel, these areas preferably abut on the wheel on opposite sides with respect to a vertical plane on which the rotation axis of the wheel lies; as said, the axial pivotal constraint about the main axis is adapted to constrain the gripping or hanging apparatus and at least one part of the abutment structure comprising at least two said abutment areas, so as to prevent the transmission of torques about the main axis between the gripping, or hanging, apparatus and said at

least one part of abutment structure, when the device is applied to the wheel; the device also comprises a seat for means for measuring the alignment of the wheel.

In practice, this pivot prevents incorrect positioning of the gripping apparatus from affecting the abutment structure, which can thus safely adhere to the wheel with the abutment areas.

The term pivot is intended as a constraint that enables a relative rotation of the two constrained parts, even when the device is associated with the wheel, i.e. when the device is ready to measure the alignment.

Advantageously, the device comprises means for adjustment (or for translation) of the axial position along the axis X of said gripping apparatus, in the form of a fixing block, for example of clamp (or sandwich) type.

Advantageously, the axial pivotal constraint and the means for adjustment (or translation) of the axial position of the gripping apparatus, are separate from one another, with the pivotal constraint always active and with the fixing constraint adapted to be active when the device is operatively arranged on the tire to measure the alignment.

According to another aspect, the invention relates to a support device applied to a wheel with tire for means for measuring the alignment of the wheel, comprising:

- an abutment structure with the wheel, comprising at least two abutment areas with the outer side of the wheel when the device is applied to the wheel,

- an apparatus for gripping the upper part of the tread of the tire of the wheel, said apparatus being constrained to said abutment structure along a main axis running from above to below, when the device is applied to the wheel,

- a seat for means for measuring the alignment of the wheel, characterized in that it comprises an axial pivotal constraint about said main axis, adapted to constrain, in a pivoting manner, said gripping apparatus and said at least one part of said abutment structure comprising at least two said abutment areas, so as to prevent the transmission of torques

about said main axis between said gripping apparatus and said at least one part of abutment structure, when the device is applied to the wheel.

Brief description of the drawings

Further characteristics and advantages of the invention will be more apparent from the description of a preferred but non-exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein :

Fig. 1 represents an axonometric view of a support device according to the invention ;

Fig. 2 is an axonometric view of the device of Fig. 1 associated with a wheel ;

Fig. 3 is a top view of the device with the support apparatus shown while it is pivoting about the aforesaid main axis;

Fig. 4 is a sectional view according to the line IV-IV of Fig. 3, of a portion of the device relating to the pivotal constraint between the gripping apparatus and part of the abutment structure;

Fig. 5 is an exploded view of the part of the device relating to the pivotal constraint;

Fig. 6 is a side view of the device as in the preceding figures;

Fig. 7 is a top view of a portion of the device, sectioned according to the line VI I-VII of Fig. 6.

Detailed description of an embodiment of the invention

With reference to the aforesaid figures, a device according to the invention is indicated as a whole with the numeral 1 0, while the wheel with which the device 1 0 is associated is indicated with 1 1 ; the rim of the wheel is indicated with 1 2 and the tire with 1 3.

The device 1 0 comprises a structure 14 for abutment with the wheel 1 1 . In particular, this abutment structure 14 has at least two abutment areas 1 5 with the outer side 1 1 A of the wheel 1 1 .

In this example, these abutment areas 1 5 are such that, when the device

1 0 is applied to the wheel 1 1 , the areas 1 5 abut on the wheel on opposite sides

"a" and "b" with respect to a vertical plane on which the rotation axis Z of the wheel lies.

Preferably, the abutment structure 14 comprises a base 16 from which there extend two arms 17. These arms are, for example, two rectilinear rods preferably aligned with each other. On each arm 17 there is provided an abutment body 18 on which there is defined a respective abutment area 15.

Each abutment body 18 comprises, for example, a cylindrical body arranged coaxially to a respective arm 17, with the respective abutment area 15 defined on the cylindrical surface of the cylindrical body.

Advantageously, the position of each abutment body 18 is adjustable along the extension of the respective arm 17 by means of adjustment means, to enable them to be adapted to wheels of different dimensions. Preferably, as shown in the figures, the abutment body 18 is perforated axially for passage of the respective arm 17; adjustment of the position of the body 18 takes place by translating the body along the arm and blocking it thereon by means of a transverse blocking element 19, for example a spring and ball screw that presses on the arm 18, passing through the body.

The device 10 also comprises an apparatus 20 for gripping the upper part 13A of the tread of the tire 13 of the wheel 1 1 . This gripping apparatus is constrained to the abutment structure 14 along a main axis X running from above to below when the device is applied to the wheel. It can be noted how the projection in the plane of the outer side of the wheel (a plane orthogonal to the rotation axis Z of the wheel) of the main axis X is transverse, preferably orthogonal, to the projection of a secondary axis Y passing through the two abutment areas 15 (or, in the example in question, the projection of the axis of the arms 18).

With the device 10 associated with the wheel 1 1 through the gripping apparatus 20, the abutment structure is hung on the tread and drops downward through gravity. The apparatus 20 is an apparatus for hanging on the wheel.

The device 10 also comprises a seat 21 for means for measuring the alignment of the wheel. For example, this seat 21 is produced on the base 16 and is provided with a measuring column 22 that extends in the opposite direction to the wheel. Preferably, the device 10 is to be associated with the wheel, as better explained below, so that the measuring column is substantially coaxial to the rotation axis Z of the wheel. On the column and on the base there can be fixed different elements useful for measuring the alignment, such as levels, emitters or receivers of signals (laser or not), etc.

Advantageously, there is provided an axial pivotal constraint 23 adapted to constrain, in a pivoting manner, the gripping apparatus 20 and the part of abutment structure 14 comprising the two said abutment areas 15. This constraint 23 makes it possible to prevent the transmission of torques about the main axis X between the gripping apparatus and this part of abutment structure, when the device is applied to the wheel.

In practice, the pivotal constraint enables, at any time and in particular when the device 10 is hung on the tire through the gripping apparatus 20, relative rotation (free rotation) of the part of abutment structure 14 comprising the two said abutment areas 15 and of the gripping apparatus 20.

Advantageously, the abutment structure 14 comprises a third abutment area 24 with the outer side of the wheel.

Preferably, from the base 16 there extends a third arm 25, such as a rectilinear rod arranged transversely, preferably orthogonally, to the two arms 18 (therefore, in the example shown in the figures, with the device 10 associated with the wheel, the third arm 25 is substantially vertical and the two arms 18 are horizontal). It can be noted that this arm 25 extends along the axis X.

On the third arm 25 there is provided a third abutment body 26, on which there is defined the third abutment area 24 with the wheel. In the preferred example, the main axis X passes through the abutment body 26.

The third abutment body 26 is preferably a cylindrical body, for example identical to the cylindrical abutment bodies 18; therefore, it is perforated axially for passage of the respective arm 25; adjustment of the position of the body 25 takes place by translating the body along the arm 25 and blocking it thereon by means of a transverse blocking element, for example a spring and ball screw that presses on the arm and passing through the body.

It can be noted how, in practice, according to a preferred optimal

configuration, the third abutment area 24 lies on a first vertex of a triangle (indicated with a broken line in Fig. 2) on the other two vertices of which the other two abutment areas 15 lie. The first vertex of the triangle is at a greater height with respect to the other two vertices (when the device is applied to the wheel); in the preferred configuration, the triangle is symmetrical with respect to the bisector of the first vertex (and is therefore isosceles or equilateral). It is understood that the abutment areas 1 5 and 24 lie on a common plane that abuts on the outer side of the wheel.

Preferably, the gripping apparatus 20 is fixed on a portion of the third arm 25 adapted to rotate freely about the main axis X on the basis of the pivotal constraint 23.

For example, see Fig. 4, the pivotal constraint 23 comprises a revolving coupling between a pin 27 and a seat 28 for rotation of the pin 27, provided respectively on a part of the structure 14 fixed with respect to the base 1 6 and on the portion of the arm 25 on which there is fixed the gripping apparatus 20 (clearly, the position of the pin and of the seat could be inverted).

For example, the seat 28 is produced from a sleeve 28A fitted inside the lower tubular end portion of the arm 25 (in practice, the sleeve is fixed to the arm and cannot move in relation thereto). The upper end 28A' of the sleeve defines a reference shoulder for a plug 29, for example a washer, to prevent movement of the rotating portion of arm 25 in the direction of extraction of the pin from the seat. This plug 29 extends laterally from the end of the pin 27 and therefore prevents extraction of the pin from the seat 28. For example, this plug 29 is fixed reversibly to the end of the pin 27 by means of a screw 30, accessible from the opposite end of the arm 25, which is tubular. Advantageously, there are arranged at the two ends of the sleeve, between sleeve and pin, two bushings 31 that facilitate rotational sliding of the pin in the seat.

Preferably, the gripping apparatus 20 comprising a block 32 for fixing to the abutment structure in an axial position along said main axis X. In this example, this block is fixed to the portion of arm 25 located along the axis X on the other part of the base 1 6 with respect to the pivotal constraint 23. For

example, the block 32 is of "clamp" type and comprises two facing parts 32A and 32B that surround the arm 25, and means 33 (such as a knob with threaded screw passing through these two parts and engaging on at least one of these parts) that adjust the distance between said two parts so as to tighten them on the arm 25, securing the block thereon.

Therefore, the device comprises means for adjustment (or translation) of the axial position along the axis X of said gripping apparatus 20, in the form of the fixing block 32.

Therefore, according to this configuration, the axial pivotal constraint 23 and the means for adjustment (or for translation) of the axial position of the gripping apparatus 20 (i.e. the fixing constraint of the block 32) are separate from one another, with the pivotal constraint 23 always active and with the fixing constraint adapted to be active when the device is operatively arranged on the tire for measuring the alignment.

From this block 32 there extend two gripping brackets 34, each of which having a first section 34A that extends from the block upward, with said device applied to the wheel, and a second section 34B (transverse to the first section) that extends from the first section 34A toward the wheel 1 1 and adapted to be arranged gripping the upper part 13A of the tread of the tire 13 of the wheel. On this second section 34B there are provided, for example, gripping teeth 34C. Preferably, this second section 34B is substantially horizontal when the device is applied to the wheel.

More in particular, in this example, the two gripping brackets 34 are pivoted to the block 32. For example, at the first section 34A, they are integral to a plate 35, which is pivoted to the block 32 according to a transverse axis K, preferably orthogonal to the main axis X, for example parallel to the arms 17. The plate 35 is positioned on the side of the block opposite the axis X with respect to the side facing the wheel, when the device is associated therewith. Between the block 32 and the plate 35 there are interposed elastic means 36, such as a body made of elastomeric material, which oppose rotation of the brackets toward the main axis X. Fig. 6 shows with a broken line the brackets 34 rotated elastically about K.

The pivot 23 is a constraint that enables relative rotation of the two constrained parts, even when the device is associated with the wheel. It is important to specify that the block 32 is constrained to the arm 25 by means of a "clamp" type constraint, which ensures that the block and the arm are mutually blocked when the device is associated with the wheel (blocking is performed by turning the knob 33). Before association of the device/wheel, the block 32 can be loose, enabling relative "rotation" and translation of the gripping apparatus 20 with respect to the arm 25: according to the invention this "clamp" type constraint is not an axial pivot (and does not allow rotation when the device is associated with the wheel).

Operation of the device is as follows. If necessary, the user adjusts the position of the abutment bodies 18 and 26 along the respective arms 17 and 25 and of the block 32 along the arm 25, in relation to the dimensions of the wheel to which the device is to be applied (the column 22 must be positioned substantially coaxial to the axis of the wheel). The user then rotates the brackets 34 to overcome the elastic resistance of the elastomeric body 36, which are therefore slightly inclined downward. With this configuration, the user places the sections 34B of the brackets 34 on the upper part 13A of the tire of the wheel, so that the teeth engage with the tread of the tire. The center of gravity of the abutment structure (base, arms, bodies, columns, etc.) is such that the structure is naturally taken to rest with the lower part thereof on the wheel, i.e. with the abutment bodies 18. The elastic rotation of the brackets acts in practice as preload, helping to push the third abutment body 26 against the wheel. The axial pivotal constraint 23 (Fig. 3 shows the rotation or pivoting of the assembly formed by arm 25 and block 32, with brackets 34, about the axis X on the pivot 23; the rotating brackets are shown with a broken line) is, for example, arranged on this arm 25, between the gripping apparatus 20 and the part of the structure that carries the two lower abutment bodies 18, and in practice "breaks up" the rigidity of the structure between the three abutment areas, thus ensuring that all three areas are in contact with the wheel. In practice, any torques applied to the structure between upper part and lower part (generated by the moment of gravity applied to the structure and by any

preload, related to the reaction of the wheel to abutment of the structure) are not transmitted between the lower and upper abutment bodies. The abutment structure and the gripping apparatus are rotationally free to rotate mutually (or pivot) at all times and in particular when the device is applied to the wheel to take the measurement.

It is understood that the drawing only shows possible non-limiting embodiments of the invention, which can vary in forms and arrangements without however departing from the scope of the concept on which the invention is based. Any reference numerals in the appended claims are provided purely to facilitate the reading thereof, in the light of the above description and accompanying drawings, and do not in any way limit the scope of protection.