Visual indication device of the coupling condition between two mechanical members

DESCRIPTION The present invention refers to a visual indication device of the coupling condition between two mechanical members.

In particular, the device of the invention has a preferred, although not exclusive, application in the field of transport, mainly in that of vehicles on wheels, to visually check the coupling condition of the wheels of such vehicles with the respective hubs.

Generally, the wheels of vehicles are clamped onto the respective hubs by means of clamping devices, typically bolts. For safety reasons, such clamping must be stable and long-lasting.

The wheel should remain in a desired coupling condition until the clamping device is deliberately removed, for example during a wheel replacement. However, it is possible for there to be an accidental clamp loosening of the wheel on the hub, for example resulting from particularly violent and repeated vibrations and stresses, generated, for example, by irregularities in the road surface, as well as resulting from inadequate positioning of the clamping device. Therefore, it is advised to periodically check the effectiveness and the good clamp hold between the aforementioned mechanical members .

In particular, it is advantageous to use a visual indication device that allows to easily identify whether there has or has not been a loosening of such a clamp.

Regarding this, the Applicant has taken into consideration a device comprising two plate elements adapted to be arranged between the wheel and the nut of the clamping bolt of the wheel at the hub, and an element made from coloured elastically deformable material arranged between the aforementioned plate elements. Such a device allows a user to be visually warned of a possible clamp loosening between wheel and hub. Indeed, when the wheel is correctly clamped onto the hub, the pressure exerted on the plate elements arranged between wheel and hub ensures that the elastically deformable material arranged here deforms, extending into the space outside of the plate elements, thus being visible to a user. Vice-versa, when the clamping between wheel and hub loosens, the elastically deformable material elastically withdraws towards the space enclosed between the two plate elements, being less visible or completely invisible to the user.

Therefore, whether or not the elastically deformable material is present outside the plate elements allows the coupling condition between wheel and hub to be visually determined.

However, the Applicant has noted a drawback in the visual indication device described above. Such a drawback occurs when the clamping of the wheel is carried out on the hub by means of automatic screwing guns. In this case, indeed, when the automatic gun is actuated to rotate, the high pressure exerted by such a gun on the externally arranged plate element (i.e. on the plate element in abutment with the nut of the bolt) ensures that the gun makes such a plate element rotate by friction, which therefore rotates with respect to the plate element in abutment against the wheel. In this situation, the portion of the element of

elastically deformable material in contact with the plate element made to rotate by the automatic gun tends to be made to rotate too, whereas the remaining portion of the element of elastically deformable material tends to remain integral with the plate element in abutment on the wheel . Consequently, the element of elastically deformable material deforms plastically, becoming unusable.

The technical problem forming the basis of the present invention is therefore to ensure that the element of elastically deformable material does not plastically deform when the clamping of the wheel on the hub is carried out by means of automatic screwing guns, so that such an element of elastically deformable material can constitute a valid visual indication means for checking the coupling condition between wheel and hub.

In accordance with the present invention, this problem is solved by a visual indication device as defined in the attached claim 1.

In particular, the present invention refers to a visual indication device of the coupling condition of a first mechanical member with a second mechanical member, said device comprising, in its assembled configuration: a first plate element adapted to operate in abutment with said first mechanical member;

- a second plate element adapted to be clamped against said first plate element; an element of elastically deformable material arranged between said plate elements; wherein:

- A -

when said mechanical members are in a desired coupling condition, said element of elastically deformable material takes up a first position such as to occupy at least a portion of space outside of said plate elements;

when said mechanical members are in a undesired coupling condition, said element of elastically deformable material takes up a second position different from said first position, the difference in position of said element of elastically deformable material being visually perceptible by a user;

wherein at least one of said first plate element and said second plate element comprises at least one tooth and at least the other one from said first plate element and said second plate element comprises at least one first seat adapted to clutch housing said tooth, so as to make said first plate element and second plate element integral with one another.

Advantageously, such a device is able to visually indicate the coupling condition between two mechanical members, without having the above outlined drawback in case automatic screwing guns are used.

Indeed, the arrangement of a clutch coupling between tooth and respective seat in the visual indication device of the present invention allows the two plate elements and, therefore, also the element of elastically deformable material arranged between said plate element to be integral with one another. Such an element of elastically deformable material therefore is not subjected to plastic deformations .

In the present description and in the subsequent claims,

the term "desired coupling condition" is used to indicate the condition wherein the first mechanical member is coupled with the second mechanical member by a clamp suitable for ensuring its use in safe operating conditions. Vice-versa, the term "undesired coupling condition" is used to indicate the opposite condition, wherein the first mechanical member is not coupled with the second mechanical member by a clamp suitable for ensuring its use in safe operating conditions. Therefore, examples of undesired coupling conditions are those wherein the aforementioned two mechanical members are not coupled or when, whilst being coupled, the clamp between such members is too weak and the coupling determined by such weak clamping could cause a dangerous situation.

Preferably, the aforementioned first mechanical member is a wheel of a vehicle, such as for example a wheel of an automobile, motorbike, motorcycle, van, motor-bus, articulated lorry, and similar, and the aforementioned second mechanical member is the hub integral with the vehicle such a wheel is adapted to be coupled to. However, it is also possible to use the device of the present invention in the clamping of different types of mechanical members, and in general in all those cases wherein it is advantageous to be able to visually check the clamping of two mechanical members .

Preferably, the aforementioned plate elements are made from sintered material, more preferably iron or sintered steel. The Applicant has indeed found that sintering allows very narrow size tolerances to be achieved, which are difficult to obtain with other different processes.

Preferably, the aforementioned tooth and the aforementioned

seat have matching shapes. By this way, when the first plate element is clamped against the second plate element, the tooth perfectly engages in the seat, making the two plate elements perfectly integral with one another.

Preferably, the tooth (and consequently also the matching shape seat) is triangular shaped. This allows to achieve a perfect centring between the two plate elements in the assembly step of the device of the present invention.

In the preferred embodiment, the two plate elements are identical in shape and in material from which they are made.

In particular, preferably, each of the aforementioned plate elements comprises both the aforementioned tooth and the aforementioned seat. More preferably, the tooth and the seat are arranged in symmetrically opposite position with respect to an axis of symmetry. Even more preferably, each of the aforementioned plate elements comprises a central circular through hole defined around said axis of symmetry and the tooth and the seat present on each plate element are arranged in diametrically opposite position with respect to the aforementioned axis of symmetry.

Advantageously, the fact that the two plate elements are made in an identical shape and from the same material allows to achieve a double clutch which improves the coupling between the two plate elements. Moreover, such a provision allows clear advantages to be achieved from the cost reduction and the production times point of view since it is possible to produce a single type of plate element suitable for operating both as first plate element and as second plate element.

Preferably, the first plate element and, more preferably, also the second plate element, comprise a second seat, having a shape matching the one of the tooth, on a surface opposite to the one in which there is the tooth and in a position corresponding to that one of the tooth. By this way, each plate element can be stacked onto the other plate elements, the tooth of each plate element clutching into the aforementioned second seat made in the plate element positioned above or below it, with clear advantages in the plate elements packaging, storage and transportation.

Preferably, the aforementioned first plate element comprises an annular line of surface discontinuity on the surface adapted to operate in abutment with the first mechanical member. Considering the fact that the surfaces of said plate elements may not be perfectly flat with a consequent decrease in the extension of the abutment surface with the first mechanical member, such a line of discontinuity allows to reduce to the minimum the shift between the abutment surfaces of the first plate element and of the first mechanical member, with the advantage of improving the coupling between these two components.

Preferably, the element of elastically deformable material is made from silicon rubber.

More preferably, the element of elastically deformable material is coloured, or more generally it has a different colour from that one of the plate elements, so as to be able to be easily detected by a user of the device of the invention.

Further characteristics and advantages of the visual indication device of the present invention shall become clearer from the following detailed description of a

preferred embodiment thereof, made as a non-limiting example with reference to the attached drawings . In such drawings,

- figure 1 is a front perspective view of a preferred embodiment of a plate element of a device according to the present invention;

- figure 2 is a rear perspective view of the plate element of figure 1;

- figure 3 is a section view of a component made from elastically deformable material adapted to cooperate with the plate element of figures 1 and 2;

- figure 4 is a section view of a preferred embodiment of a device according to the present invention in the assembly step;

- figure 5 is a section view of the assembled device of figure 4.

With reference to figures 1 and 2, a preferred embodiment of a plate element 10 of a visual indication device of the coupling condition between two mechanical members in accordance with the present invention is shown, such a device being indicated with 1 in figures 4 and 5. The plate element 10 is adapted to operate in abutment with a first mechanical member (not shown in the figures) .

The plate element 10 comprises a circular shaped body 100 having an axis of symmetry X-X. The body 100 is centrally provided with a circular through hole 4 and comprises, at a front surface 10a of the body 100, a tooth 11 and a recess 12, the tooth 11 and the recess 12 being arranged in diametrically opposite position with respect to the axis of

symmetry X-X .

The tooth 11 and the recess 12 have matching shapes. Preferably, as illustrated in the attached figures, the tooth 11 and the recess 12 are triangular shaped.

The tooth 11 and the recess 12 are formed, in particular, on an annular flange 101 radially inside the body 100, said flange 101 extending in the direction of the axis X-X.

The body 100 of the plate element 10 further comprises a radially outer annular flange 102 extending in the direction of the axis X-X too, but for a length portion shorter than that one of the flange 101.

The body 100 of the plate element 10 comprises a recess 22 having a shape matching that one of the tooth 11, on a surface 10b opposite the surface 10a wherein is present the tooth 11 and in a position corresponding to that one of the tooth 11 itself (figure 2) .

From figures 1 and 2 it can be seen that the body 100 of the plate element 10 further comprises, on the surface 10b, a circular closed line 13 defining a surface discontinuity. The plate element. 10 is made from sintered material, preferably iron or sintered steel.

The plate element 10 is adapted, in use, to be clamped against a second plate element 20 adapted to operate in abutment against a second mechanical member (not shown in the figures too) . In the use of the device of the present invention, the surface 10b of the plate element 10 is adapted to operate in abutment with one of the two mechanical members to be clamped (for example a wheel to be clamped onto the hub of a vehicle), while the surface 10'b

of the plate element 20 is adapted to operate in abutment with the other mechanical member (for example a nut of a clamping bolt of the wheel at the hub of a vehicle) .

In the preferred embodiment of the device of the present invention, the second plate element 20 is identical to the plate element 10 in shape and in the material from which it is made; therefore, the plate element 20 too comprises all the constituent elements described above with reference to the plate element 10. In the figures, such constituent elements are indicated with the same reference numeral used for the plate element 10, with the addition of an apostrophe.

The recess 12,12' of each plate element 10,20 acts as a housing seat for the tooth 11,11' of the other plate element when the two plate elements are clamped against one another in the use of the device of the present invention. On the other hand, the recess 22,22' of each plate element acts as a housing seat for the tooth 11, 11' of the other plate element when the various plate elements are stacked on top of one another in packaging, transportation and storage of such plate elements. Therefore, the recesses 12,12' and 22,22' shall also be indicated with the term "seats" in the rest of the present description and in the subsequent claims.

The device 1 of the present invention further comprises an element 3 made from elastically deformable material, for example silicon rubber. Such an element 3 is preferably made in a ring shape, as schematically illustrated in figure 3, and is adapted in use to be arranged between the plate elements 10 and 20. In particular, such an element 3 made from elastically deformable material is fitted onto the radially inner flange 102 of the plates 10,20.

Figure 4 shows the device 1 according to the present invention in the assembly step. In this step, the seat 12 of the plate element 20 is arranged to clutch housing the tooth 11 of the plate element 10 thus allowing the two plate elements 10,20 to be integral with one another.

Figure 5 shows the plate elements 10,20 when they are clamped one against another, so as to make the desired coupling condition between the first and the second mechanical member (not shown in the figures) . In this condition, the element 3 made from elastically deformable material deforms occupying a space outside the plate elements 10,20 so as to be visually perceptible by a user that frontally looks at the device of the present invention.

The shape and the size of said space occupied by the element 3 made from elastically deformable material shall depend upon the type of the elastically deformable material and upon the shape and size of the plate elements.

Of course, the above described embodiment must be considered as a mere non-limiting illustration of some possible embodiments of the device of the present invention, being obviously understood that any constituent element of the device itself can be changed by the man skilled in the art in order to satisfy specific and contingent requirements, whilst still being covered by what is claimed.