WO2017089055A1

WO2017089055A1 - Method of verifying the correct mounting of a fastening clip, and fastening clip

Info

Publication number: WO2017089055A1
Application number: PCT/EP2016/075626
Authority: WO
Inventors: Roland Claßen
Original assignee: Itw Fastener Products Gmbh
Priority date: 2015-11-24
Filing date: 2016-10-25
Publication date: 2017-06-01
Also published as: CN108290528A; DE102015120331A1

Abstract

A method of verifying the correct mounting of a fastening clip (10) which includes an expansion element (12) which is transferred translationally from a preassembly position to a final assembly position during assembly, the expansion element (12) having a head (18) with a wing (20) provided thereon the orientation of which in relation to the head (18) is changed when the expansion element (12) is transferred from the preassembly position to the final assembly position, and at least two reference elements (22, 23) being provided, one of which is arranged on the wing (20), the method comprising the steps of: displacing the expansion element (12) from the preassembly position to the final assembly position; measuring the location of the reference elements (22, 23) in relation to each other; comparing the location of the reference elements (22, 23) with a comparative value when the expansion element (12) is in the final assembly position; recognizing the mounting as being "i.o." (in order) or "n.i.o." (not in order), depending on the result of the comparison. Further proposed is a fastening clip (10) which can be used in accordance with the corresponding method.

Description

Method of Verifying the Correct Mounting of a Fastening Clip,

and Fastening Clip

The invention relates to a method of verifying the correct mounting of a fastening clip, and a fastening clip. Fastening clips are made use of for fixing add-on parts to a vehicle body quickly and securely. The fastening clip includes, for example, a detent section which is inserted into a vehicle opening and snaps in place therein, and an expansion element that is inserted into the detent section. The component to be fastened (e.g., a lining part or a gas bag module) is fixed in place either directly by means of the detent section, for instance if the latter is in the form of an attachment clip, or to a body that is provided on the detent section, for instance if the latter is in the form of a plug. The component to be fastened may also be fastened to the expansion element.

In a fastening clip configured in two parts, the detent section and the expansion element are provided with complementary detent elements which are moved into engagement with each other by insertion. In the final mounting position in the inserted state, the expansion element also prevents the detent section from being able to be pulled out of the opening of the vehicle body.

It is known to prefix the detent section and the expansion element to each other in a preassembly position for ease of processing, so that the fastening clip can be handled as one single component. In the preassembly position, the detent section can be inserted into the opening in the vehicle body, and the component to be fastened can be fixed in place at the fastening clip. For finally fixing the fastening clip to the vehicle body, the expansion element is then moved from its preassembly position to the final assembly position.

In a fastening clip configured in one piece, the detent section and the expansion element are integrally connected with each other. The expansion element is loaded in the insertion direction to lock the detent section in place in the opening.

In this case, the preassembly position corresponds to a position in which the detent section has not yet, or not yet completely, been inserted into the opening. A good many of such fastening clips are used in a vehicle, often in places that are difficult to see or access. It is desirable, but complicated to have a proof that all of the fastening clips were correctly locked in the final assembly position.

DE 10 201 1 009 683 A1 shows a fastening clip with a code that can be read only in the case of a correct mounting, and in this way allows an automated verification of the state of installation of the fastening clip.

However, the code requires a relatively large, preferably flat surface, which limits the designing of the fastening clip. A further drawback is the costs involved in applying the code.

The object of the invention is to allow a verification of the correct mounting of a fastening clip in a simple and cost-effective way.

According to the invention, this object is achieved by a method of verifying the correct mounting of a fastening clip which includes an expansion element which is transferred translationally from a preassembly position to a final assembly position during assembly, the expansion element having a head with a wing provided thereon the orientation of which in relation to the head is changed when the expansion element is transferred from the preassembly position to the final assembly position, and at least two reference elements being provided, one of which is arranged on the wing, the method including the steps of: displacing the expansion element from the preassembly position to the final assembly position; measuring the location of the reference elements in relation to each other; comparing the location of the reference elements with a comparative value when the expansion element is in the final assembly position; recognizing the mounting as being "i.o." or "n.i.o.", depending on the result of the comparison.

By reducing the correct mounting to the relative location of two reference elements in relation to each other, this information and therefore the installation state of the fastening clip can be determined very rapidly and simply.

In this context, "i.o." means "in order", denoting a proper and correct final installation state, whereas "n.i.o." means "not in order", denoting an installation state which is considered inadequate or improper and is therefore defined as incorrect. The preassembly position is a position in which the expansion element is in a non-final installation state. The fastening clip is normally delivered with an expansion element in this position and can be preassembled for a preliminary fastening, for example.

The final assembly position is a position into which the expansion element has already been shifted from its preassembly position, so that now it is either in a correct final installation state or in an installation state that does not indicate a correct mounting and is therefore considered to be incorrect.

The comparative value is a pre-specified value or range that is utilized for assessing the installation state of the fastening clip and in particular comprises a distance.

Preferably, the comparative value is a type-specific value that is stored in a database. This ensures a best possible assessment of the installation state and prevents an incorrect value from being used in the verification. In addition, in this way, individual comparative values may also be made use of in the verification of the correct mounting of different fastening clips if the type of the fastening clip that is currently to be checked is known. The respective comparative values are then retrieved from the database on the basis of the information of the fastening clip in question. Here, the type of the fastening clip may either be part of the information about the assembly that is currently located at the checking station, or else, alternatively, it can be determined in an additional process step. Provision may be made that the comparative value is obtained by individually detecting the reference elements before the expansion element is transferred from the preassembly position to the final assembly position. In this way, the respective comparative value necessary for a correct mounting is determined based on the fastening clips that are present at a particular time, as a result of which it is ensured that even in the case of different fastening clips they are correctly mounted.

According to an advantageous embodiment, the location of the reference elements is determined by the orientation of the wings in relation to the head. The advantage of this is that the reference elements may also be situated at places that can not be detected directly. Furthermore, the orientation of the wing that may be simpler to determine may be used as an alternative or in addition to the location of the reference elements for the assessment of the installation state. In particular, here the wing is detected in a side view perpendicular to the shifting direction of the expansion element.

According to a further advantageous embodiment, the angle of the wing in relation to an outer edge of the head is measured. The angle here offers a further possibility of determining the correct mounting of the fastening clip.

Preferably, the location of the reference elements is the distance of the two reference elements from each other. The distance is particularly suitable since it can be determined simply and reliably. In particular, the distance of the reference elements is detected in a top view along the shifting direction of the expansion element here.

Two wings may be attached to the head of the expansion element on sides facing away from each other. This provides more options for the design of the fastening clip and also in the verification of the correct mounting, which can thereby be checked in an even more reliable manner. For example, the orientation of both wings can be detected and an obliquely positioned expansion element can be identified in this way. In an advantageous embodiment, the angle at which the at least one wing extends in relation to a plane that is perpendicular to the shifting direction of the expansion element is reduced when the expansion element is shifted from the preassembly position to the final assembly position. The fastening clip can be configured such that this movement of the wings automatically results from the translational movement of the expansion element and their orientation in the proper final state of installation is clearly defined. As a result, mounting is simple since there are no additional steps be to considered, and the proper installation state can be reliably determined.

In a further advantageous embodiment, a first camera is used in a predetermined first position for measuring the distance of the reference elements from each other and, alternatively or additionally, a second camera is used in a predetermined second position for measuring the spatial location of the at least one wing. Cameras, such as, e.g., in the form of a CCD chip, constitute a cost- efficient option for measuring the parameters. Owing to the low costs, it is also possible to employ a plurality of cameras for the measurements. This allows a plurality of parameters to be determined simultaneously, as a result of which process time is reduced while process reliability is increased at the same time.

Preferably, the first camera is used with a viewing direction parallel to the shifting direction of the expansion element and/or the second camera is used with a viewing direction perpendicular to the shifting direction of the expansion element. In this way, the cameras are in optimum positions and orientations so as to carry out the measurements faster and more accurately.

It is of advantage if a check is performed as to whether the distance and/or the location could be measured at all, and that an error signal is output if the distance and/or the location could not be measured. The check reduces the risk that any fastening clips that were not properly mounted will not be detected. Using the error signal, various process steps can be controlled which are initiated if the measurement of the distance and/or of the location of a fastening clip could not be carried out correctly. Examples of such additional process steps include repeating the measurement, forwarding an information about the incorrect measurement, and marking the fastening clip for a manual inspection. To achieve the above-mentioned object, provision is further made for a fastening clip the correct mounting of which can more particularly be verified in a method of the above-mentioned type. The fastening clip comprises an expansion element which can be transferred translationally from a preassembly position to a final assembly position during assembly, at least one head having at least one wing attached thereto, and at least two reference elements.

According to an advantageous embodiment, the reference elements are formed by edges of the fastening clip and/or by parts of the fastening clip. In this way, no additional markings are required and the fastening clip can be produced in a cost-effective manner.

According to a further advantageous embodiment, the reference elements are markings which more particularly are printed on, glued on or impressed. The markings serve to increase the detectability of the reference elements and in this way to accelerate the verification of the correct mounting of the fastening clip and to make it more reliable.

Preferably, the reference elements distinctly differ from their surroundings by their chemical and/or physical properties. This makes it easier to detect the reference elements, allowing a faster verification. Further advantages and features will be apparent from the description below, given in conjunction with the accompanying drawings, in which:

- Figure 1 shows a perspective view of a fastening clip according to the invention, in a preassembly position;

- Figure 2 shows a top view of the fastening clip according to the invention from Figure 1 ;

- Figure 3 shows a schematic side view of the fastening clip according to the invention from Figure 1 ;

- Figure 4 shows a perspective view of the fastening clip according to the invention from Figure 1 , in the final assembly position; - Figure 5 shows a top view of the fastening clip according to the invention from Figure 4;

- Figure 6 shows a schematic side view of the fastening clip according to the invention from Figure 4; and - Figure 7 shows a schematic side view of the fastening clip according to the invention and an arrangement of two cameras for checking the installation state.

Figure 1 shows a fastening clip 10 in the preassembly position, which comprises an expansion element 12 and a holding section 14. The expansion element 12 includes a detent section 16 and a head 18 having two wings 20, 21 which are adjustably connected with the head 18 on sides facing away from each other. For this purpose, a film hinge may be used.

Each wing 20, 21 includes a reference element 22, 23 which, in this embodiment, is formed by the edges of the wings 20, 21 arranged opposite to the edges by which the wings 20, 21 are fastened to the head 18.

The expansion element 12 and the holding section 14 are movable with respect to each other in the shifting direction E. To shift the fastening clip 10 from the preassembly position to the final assembly position, the expansion element 12 is displaced into the holding section 14 in the shifting direction E. Figure 2 illustrates, in a viewing direction parallel to the shifting direction E of the expansion element 12, the distance l_i of the two reference elements 22, 23 in the preassembly position.

Figure 3 shows the head 18 of the fastening clip 10 in a side view perpendicular to the shifting direction E of the expansion element 12. In the preassembly position, the wings 20, 21 are oriented in relation to an outer edge 24 of the head 18 at an angle a which is markedly greater than 0 degrees. In the exemplary embodiment shown, an angle a of about 45 degrees is used.

Figures 4 to 6 show the fastening clip 10 in the final assembly position, in which the expansion element 12 has been displaced in the shifting direction E to a position in which the detent section 16 has snapped in place with the holding section 14.

Displacement of the expansion element 12 causes the wings 20, 21 to be shifted in position by the holding section 14. This changes both the orientation of the wings 20, 21 and the location of the reference elements 22, 23 relative to each other, which now have a distance L₂ from each other which is greater than the distance U in the preassembly position. In the side view perpendicular to the shifting direction E of the expansion element 12, the wings 20, 21 when in the final assembly position are oriented approximately parallel to the outer edge 24 of the head 18; the amounts to about 0 degrees.

In an alternative embodiment, the fastening clip 10 may be configured such that the distance between the reference elements 22, 23 and the angle a of the wings 20, 21 increases or decreases, respectively, when the fastening clip 10 is shifted from the preassembly position to the final assembly position. The only important factor here is that the amount of change is sufficiently large to allow the actual installation state of the fastening clip 10 to be reliably determined. In a method according to the invention for verifying the correct mounting of the fastening clip 10 from Figures 1 to 6, provision is made for the following steps.

After the expansion element 12 has been shifted from the preassembly position to the final assembly position in a first step, the location of the reference elements 22, 23 in relation to each other is determined in a second step with the aid of two cameras 26, 27 (see Figure 7).

The first camera 26 is arranged in a first position with a viewing direction parallel to the shifting direction E of the expansion element 12 and measures the distance L of the reference elements 22, 23. The second camera 27 is arranged in a second position with a viewing direction perpendicular to the shifting direction E of the expansion element 12 and determines the orientation of the wings 20, 21 in relation to the head 18 by measuring the angle a.

In a third step, an inspection is performed to check whether the distance L and/or the angle a could be measured at all. In case of failure of the check, an error signal is output, by means of which further process steps can be initiated to remedy the situation.

In a fourth step, the measured results that have been ascertained regarding the location of the reference elements are compared with appropriate type- specific comparative values stored in a database. The type-specific comparative values are predefined in this case, but, in an alternative embodiment they may also be determined by individually detecting the reference elements 22, 23 before the expansion element 12 is transferred from the preassembly position to the final assembly position. In a fifth step, depending on the result of the comparison, the mounting is recognized as being "i.o.", that is, "in order", or as being "n.i.o.", that is, "not in order", and the assembly is directed to an appropriate next process step.

Additionally or alternatively, the fastening clip 10 may be marked, preferably electronically, to allow an easy identification of the fastening clip 10 in question for a manual inspection for example in case of a "n.i.o." result.

The embodiment illustrated in Figures 1 to 6 includes two wings 20, 21 . But a fastening clip 10 having more than two wings 20, 21 or only one wing 20, 21 can also be realized. The positions of the reference elements 22, 23 and the detection thereof will be adapted accordingly. The mirror-symmetric design of the fastening clip 10 makes sure that when the expansion element 12 is displaced into the holding section 14 in the shifting direction E, the orientation of the wings 20, 21 will change synchronously and, thus, the angle a is the same for both wings 20, 21 .

But it is also possible that, in an alternative embodiment, one or more wings 20, 21 of the fastening clip 10 are oriented individually relative to the head 18 and/or change their orientations individually when the fastening clip 10 is shifted from the preassembly position to the final assembly position. The result is that there are several different angles a, which have to be detected separately from each other if they are relevant to the verification of the correct mounting of the fastening element 10.

In a further alternative embodiment, the reference elements 22, 23 may be applied fully or partly in the form of markings to the fastening clip 10, which are more particularly printed on, glued on or impressed. These markings distinctly differ from their surroundings, preferably by their chemical and/or physical properties, as a result of which they are easier to detect by the cameras 26, 27. To this end, a coating may be used, for example, which emits light in a particular wavelength range to which the cameras 26, 27 respond especially sensitively. The markings more particularly differ so distinctly from their surroundings that the reference elements 22, 23 can be reliably detected in a very short time, for instance in less than 0.2 seconds.

In particular, for producing the markings, provision may also be made for a laser which applies the markings onto the fastening clip 10 in a very short time, for instance in less than 0.8 seconds.

Claims

1. A method of verifying the correct mounting of a fastening clip (10) which includes an expansion element (12) which is transferred translationally from a preassembly position to a final assembly position during assembly, the expansion element (12) having a head (18) with a wing (20) provided thereon the orientation of which in relation to the head (18) is changed when the expansion element (12) is transferred from the preassembly position to the final assembly position, and at least two reference elements (22, 23) being provided, one of which is arranged on the wing (20), the method comprising the steps of:

- displacing the expansion element (12) from the preassembly position to the final assembly position;

measuring the location of the reference elements (22, 23) in relation to each other;

comparing the location of the reference elements (22, 23) with a comparative value when the expansion element (12) is in the final assembly position;

recognizing the mounting as being "i.o." (in order) or "n.i.o." (not in order), depending on the result of the comparison.

2. The method according to claim 1 , characterized in that the comparative value is a type-specific value which is stored in a database.

3. The method according to claim 1 , characterized in that the comparative value is obtained by individually detecting the reference elements (22, 23) before the expansion element (12) is transferred from the preassembly position to the final assembly position.

4. The method according to any of claims 1 to 3, characterized in that the location of the reference elements (22, 23) is determined by the orientation of the wings (20) in relation to the head (18).

5. The method according to claim 4, characterized in that the angle (a) of the wing (20) in relation to an outer edge (24) of the head (18) is measured.

6. The method according to any of claims 1 to 3, characterized in that the location of the reference elements (22, 23) is the distance (L) of the two reference elements (22, 23) from each other.

7. The method according to any of the preceding claims, characterized in that two wings (20, 21 ) are attached to the head (18) of the expansion element

(12) on sides facing away from each other.

8. The method according to any of the preceding claims, characterized in that when the expansion element (12) is shifted from the preassembly position to the final assembly position, the angle (a) at which the at least one wing (20, 21 ) extends in relation to a plane that is perpendicular to the shifting direction (E) of the expansion element (12) is reduced.

9. The method according to any of the preceding claims, characterized in that a first camera (26) is used in a predetermined first position for measuring the distance (L) of the reference elements (22, 23) from each other and/or a second camera (27) is used in a predetermined second position for measuring the spatial location of the at least one wing (20, 21 ).

10. The method according to claim 9, characterized in that the first camera (26) is used with a viewing direction parallel to the shifting direction (E) of the expansion element (12) and/or the second camera (27) is used with a viewing direction perpendicular to the shifting direction (E) of the expansion element (12).

1 1 . The method according to any of the preceding claims, characterized in that a check is performed as to whether the distance (L) and/or the location could be measured at all, and that an error signal is output if the distance (L) and/or the location could not be measured.

12. A fastening clip (10), in particular for use in a method according to any of the preceding claims, comprising an expansion element (12) which can be transferred translationally from a preassembly position to a final assembly position during assembly, at least one head (18) having at least one wing (20, 21 ) attached thereto, and at least two reference elements (22, 23).

13. The fastening clip according to claim 12, characterized in that the reference elements (22, 23) are formed by edges of the fastening clip (10) and/or parts of the fastening clip (10).

14. The fastening clip according to either of claims 12 and 13, characterized in that the reference elements (22, 23) are markings which more particularly are printed on, glued on or impressed.

15. The fastening clip according to any of claims 12 to 14, characterized in that the reference elements (22, 23) distinctly differ from their surroundings by their chemical and/or physical properties.