method of fixing a first structure to a second structure by means of guided screws.
The method addresses the issue of unstable fixation by using a guide ring to recenter the enlarged opening of the first structure onto the tapped hole of the second structure during screwing, ensuring a robust and stable attachment.
Patent Information
- Application Number
- FR2023004146
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-04-25
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2043-04-25
AI Technical Summary
The existing method of fixing a first structure to a second structure using guided screws is unsatisfactory when the enlarged opening of the first structure is not precisely centered on the tapped hole of the nut of the second structure, leading to unstable and potentially loose fixation over time.
A method utilizing a guide ring with a funnel-shaped guide zone is introduced, allowing the first structure to be systematically aligned and recentered relative to the second structure during screwing, ensuring precise positioning and robust fixation.
The method ensures a robust and stable fixation between the two structures by precisely aligning the enlarged opening with the tapped hole, preventing premature contact and ensuring the flared section of the screw engages correctly with the second structure.
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Abstract
Description
Title of the invention: method of fixing a first structure to a second structure by means of guided screws.
[0001] The present invention relates to a method of fixing a first structure to a second structure by means of guided screws.
[0002] In order to better understand the positioning of the different parts involved in a method according to the invention, the description is carried out with reference to a direct orthonormal reference frame XYZ linked to a vehicle in which said method would be applied, and in which X is a front-rear longitudinal axis of the vehicle oriented towards the rear, Y is a transverse axis oriented towards the right of the vehicle and Z is a vertical axis directed upwards.
[0003] In certain situations, it may happen that: -the second structure has at least one nut with a threaded hole, and -the first structure has an enlarged opening, and -the first structure and the second structure are first pre-positioned relative to each other so that the enlarged opening is centered over the threaded hole of the nut, and then are secured to each other by means of at least one screw having a shoulder and a threaded rod. Said screw first passes through the enlarged opening before the threaded rod is inserted into the threaded hole and then screwed into it to secure the first structure to the second structure.
[0004] However, it may happen that the enlarged opening of the first structure is not precisely centered on the tapped hole of the nut of the second structure. This causes the shoulder of the screw to come into abutment against an area of the first structure delimiting the enlarged opening whereas said shoulder should be completely inserted into said enlarged opening. As a result, the screw fixing of the first structure to the second structure is not satisfactory, since said screw is not correctly placed on said two structures. Such an approximate assembly could make the fixing between the two structures unstable with risks of drift over time which could lead to a separation of said two structures from each other.
[0005] A fixing method according to the invention makes it possible to systematically position the two structures to be fixed to each other in a satisfactory position, so that the fixing between them is robust and stable.
[0006] The subject of the invention is a method of fixing a first structure to a second structure by means of a screw having a cylindrical threaded rod and a flared cylindrical section whose diameter is greater than that of the threaded rod, the second structure having a nut comprising a tapped hole intended to receive the threaded rod of the screw and the first structure having an enlarged opening of circular shape.
[0007] According to the invention, the method comprises the following steps: - a step of fixing a ring having a funnel-shaped guide zone in the enlarged opening of the first structure, - a step of aligning the enlarged opening provided with the ring with the tapped hole of the nut of the second structure, - a step of introducing the threaded rod into the tapped hole of the nut of the second structure, - a step of screwing the screw into the nut allowing the flared section to come into contact with the ring, if the enlarged opening is not perfectly centered on the tapped hole of the nut, - a step of continuing the screwing causing the flared section to press against the ring and therefore a movement of the enlarged opening which tends to refocus on the tapped hole of the nut, - a step of stopping the screwing when the enlarged opening is perfectly centered on said tapped hole, the flared section coming into contact with the second structure.
[0008] The principle of a fixing method according to the invention is to implement a guide ring allowing, in the case where the enlarged opening of the first structure is not perfectly aligned with the tapped hole of the nut of the second structure, to move the first structure during an operation of screwing the screw into said tapped hole in order to recenter said enlarged opening on said tapped hole of the nut. This prevents in particular the flared section of the screw from coming, for example, into contact with a zone of the first structure delimiting the enlarged opening, whereas said flared section should come into contact with a zone of the second structure delimiting the tapped hole of the nut in the case of satisfactory fixing of the first structure on the second structure.This ring acts as a guide which will orient the movement of the first structure relative to the first structure when the threaded rod is screwed into the tapped hole, so as to refocus the enlarged opening of said first structure on the tapped hole of the nut of the second structure. A guide zone of the funnel-shaped ring means that said zone has a first opening of reduced size and a second opening of larger size than that of said first opening, the cross-section of this guide zone varying monotonically between said ends. The ring is rigid and is designed not to deform when the flared section of the screw rests on it during an operation of screwing the screw into the nut. The expression "not to deform" does not exclude that locally said ring undergoes a low elastic deformation. amplitude, the important thing being that said ring does not deform plastically. Advantageously, the screw has an enlarged head whose diameter is greater than that of the flared section, so that said flared section is placed between said enlarged head and the threaded rod. The screw has a shoulder between the flared section and the threaded rod. The first structure and the second structure may for example represent two separate pieces of equipment of a vehicle to be fixed to each other by means of at least one screw. It is important to emphasize that if, from the start, the first structure and the second structure are correctly positioned relative to each other before the screwing operation, that is to say if the enlarged opening of the first structure is well centered on the tapped hole of the nut of the second structure, the ring having the guide zone has no particular function.
[0009] According to a possible characteristic of the invention, the guide zone of the ring is delimited by an enlarged upstream opening and by a reduced-sized downstream opening, the step of introducing the threaded rod into the tapped hole of the second structure being preceded by a step of passing said threaded rod first into the enlarged upstream opening of the ring and then into the reduced-sized downstream opening of said ring. In this way, as the threaded rod is screwed into the tapped hole of the nut, the flared section of the screw will exert an increasingly marked thrust on the ring, thus causing the displacement of the first structure relative to the second structure. The terms "upstream" and "downstream" are to be considered in relation to the direction of movement of the screw before it penetrates the nut.
[0010] According to a possible characteristic of the invention, the first structure is a seat structure of a vehicle seat or bench, the second structure being a backrest structure of said seat or said seat. This is an illustrative example for which a fixing method according to the invention is particularly suitable, but in no way a limiting example.
[0011] Another subject of the invention is a guide ring for carrying out a fixing method according to the invention.
[0012] According to the invention, the ring comprises a funnel-shaped guide zone and a fixing zone having an annular peripheral groove intended to receive an annular zone of the first structure delimiting the enlarged opening. Once the ring has been inserted into the enlarged opening of the first structure, it must no longer be able to be moved in said opening. It is therefore important that the contact between said ring and said first structure is extended, in order to reinforce its robustness. It is understood that the annular groove is produced on an external surface of the ring. Preferably, the annular groove extends 360° around the ring. The ring thus has a fixing zone which plays no guiding role, and a guiding zone which exerts no influence on its fixing to the first structure. is clear that the functional part of the ring is represented by the guide zone.
[0013] According to a possible characteristic of the invention, the annular peripheral groove of the fixing zone is delimited by two circular rails parallel to each other, between which an annular zone of the first structure delimiting the enlarged opening is intended to be inserted. The two parallel rails perfectly delimit the annular groove, and will reinforce the mechanical hold of the ring on the first structure, without the risk of seeing said ring come out of said first structure because of a groove whose relief would be little marked.
[0014] According to a possible characteristic of the invention, the guide zone extends the fixing zone and is in the form of a truncated cone-shaped wall. In this way, the cross-section of the guide zone varies continuously, regularly and progressively.
[0015] According to a possible characteristic of the invention, the frustoconical wall is delimited along its axis of revolution by a first circular end of reduced diameter and by a second circular end of enlarged diameter, said frustoconical wall being connected to the fixing zone by said first circular end. The second circular end of enlarged diameter materializes a distal end of the ring. It is understood that the diameter of the first circular end is less than that of the second circular end.
[0016] According to a possible characteristic of the invention, the frustoconical wall has a smooth internal surface. Such a smooth internal surface will promote the sliding of the flared section of the screw against said frustoconical wall.
[0017] According to a possible characteristic of the invention, the ring is made of plastic material. It is important that the ring does not weigh down the two structures once they have been fixed to each other.
[0018] Another object of the invention is an assembly of a first structure comprising an enlarged opening and a ring having a funnel-shaped guide zone and fixed in said enlarged opening, for carrying out a fixing method according to the invention. In this way, such an assembly will facilitate the progress of a fixing method according to the invention, because it can be carried out in a particular place which is not necessarily the place of fixing of the two structures. Indeed, the fixing of the ring on the first structure can be carried out in a separate place, thus limiting the operations at the place of fixing of the two structures. This could result in a significant saving of time.
[0019] A fixing method according to the invention has the advantage of systematically ensuring a quality fixing between two structures, thanks to an original implementation of a guide ring of simple geometry, and therefore easy to manufacture. This guide ring also has the advantage of being light and compact, and is designed to facilitate the attachment between the said two structures.
[0020] A detailed description of a preferred embodiment of a fixing method according to the invention is given below, with reference to the following figures:
[0021] [Fig-1] [Fig.l] is a perspective view of a seating structure and a backrest structure intended to be fixed to each other by means of a fixing method according to the invention,
[0022] [Fig.2] [Fig.2] is a schematic perspective view of a poor quality attachment point between a seat structure and a backrest structure,
[0023] [Fig.3] [Fig.3] is a schematic sectional view of a fixing point between a seat structure and a backrest structure, illustrating a first step of a fixing method according to the invention,
[0024] [Fig.4] [Fig.4] is a schematic sectional view of a fixing point between a seat structure and a backrest structure, illustrating a second step of a fixing method according to the invention,
[0025] [Fig.5] [Fig.5] is a schematic sectional view of a fixing point between a seat structure and a backrest structure, illustrating a third step of a fixing method according to the invention,
[0026] [Fig.6] [Fig.6] is a perspective view of a guide ring according to the invention,
[0027] [Fig.7] [Fig.7] is a perspective view of the attachment point of [Fig.4].
[0028] Referring to [Fig.l], certain vehicle benches 1 comprise a seat structure 2 and a backrest structure 3 intended to be fixed to each other by means of at least two screws 4, 5.
[0029] Schematically, the seat structure 2 comprises two elongated parallel bars 6, 7, including a rear elongated bar 6 and a front elongated bar 7, said two bars 6, 7 extending along a transverse axis Y of the vehicle. The seat structure 2 also comprises two shortened parallel bars 8, 9 extending along a longitudinal axis X of said vehicle, the two elongated bars 6, 7 and the two shortened bars 8, 9 forming a rectangular frame extending in a horizontal plane. Each of the two shortened parallel bars 8, 9 is extended at its junction with the rear elongated bar 6 by an elongated vertical bar 10, 11. Each of the two vertical bars 10, 11 has at an upper end, a widened circular opening 12, said upper end being considered relative to a vertical and longitudinal axis of said vertical bar 10, 11.Each of the two enlarged circular openings 12 is inscribed in a vertical and longitudinal plane XZ of the vehicle, so that the axis of revolution of each of these enlarged circular openings 12 extends along a transverse axis Y of the vehicle.
[0030] Schematically, the folder structure 3 comprises two parallel bars elongated 13, 14, including an upper elongated bar 14 and a lower elongated bar 13 extending along a transverse axis Y of the vehicle, the upper elongated bar 14 being placed above the lower elongated bar 13. The backrest structure 3 also comprises two shortened parallel bars 15, 16 extending along a vertical axis, the two elongated bars 13, 14 and the two shortened bars 15, 16 forming a rectangular frame extending in a vertical and transverse plane YZ of the vehicle. Each of the two shortened parallel bars 15, 16 is extended at its junction with the lower elongated bar 13 by a bar 17, 18 extending substantially downwards. Each of the two shortened parallel bars 15, 16 has, in a lower area which is placed just above the lower elongated bar 13, a fixing lug 19, 20 extending in a vertical and longitudinal plane XZ of the vehicle.
[0031] Referring to Figures 2, 3, 4, 5 and 7, each fixing lug 19, 20 supports a nut 21 having a cylindrical tapped hole 22 passing through both the fixing lug 19, 20 and the nut 21. The tapped hole 21 extends along a transverse axis Y of the vehicle.
[0032] Referring to Figures 2, 3, 4, 5 and 7 the seat structure 2 and the backrest structure 3 are fixed to each other, first by aligning each enlarged opening 12 of the seat structure 2 with the threaded hole 22 of the nut 21 which is secured to a fixing lug 19, 20 of the backrest structure 3. Once this alignment has been established, a fixing screw 30 is first introduced into the enlarged opening 12, and is then screwed into the threaded hole 22 of the nut 21. More precisely, each fixing screw has a cylindrical threaded rod 31, a flared cylindrical section 32 and an enlarged cylindrical head 33, the diameter of said enlarged head 33 being greater than the diameter of said flared section 32, itself being greater than that of said rod threaded 31. It should be noted that the flared section 32 is placed between the enlarged head 33 and the threaded rod 31.
[0033] Referring to Figures 5 and 7, when the fixing is satisfactory, the threaded rod 31 of the screw 30 is screwed into the tapped hole 22 of the nut 21 until the flared section 32 of said screw 30, which is completely inserted into the enlarged circular opening 12 of the seat structure 2, comes into abutment against the fixing lug 19, 20 of the backrest structure 3 carrying the nut 21.
[0034] However, referring to [Fig. 2], it may happen that when attempting to align the enlarged opening 12 of the seat structure 2 with the tapped hole 22 of the nut 21 of the backrest structure 3, said enlarged opening 12 is not perfectly centered on said tapped hole 22. In this case, during a screwing operation, the movement of the screw 30 will be shortened due to premature contact of the flared section 32 with a wall of the seat structure 2 delimiting the enlarged opening 12, as as indicated by arrow 34 appearing in [Fig.2]. For this configuration, the attachment of the seat structure 2 to the backrest structure 3 is of poor quality and presents a marked instability.
[0035] In order to prevent a final misalignment between the enlarged opening 12 of the seat structure 2 and the threaded hole 22 of the nut 21 of the backrest structure, a fixing method according to the invention uses a guide ring 40.
[0036] Referring to Figures 3, 4, 5, 6 and 7, the guide ring 40 comprises a fixing zone 41 and a guide zone 42, said two zones 41, 42 being in continuity with one another and arranged coaxially with respect to one another. The fixing zone 41 is cylindrical and has an external annular groove 43, delimited by two peripheral and parallel rails 44, 45 each extending over 360° around the fixing zone 41. These two rails 44, 45 are materialized by two parallel annular walls, originating at a bottom of the groove 43 and extending towards the outside of said groove. It should be noted that the two rails 44, 45 are separate. Among these two rails, an internal rail 44 and an external rail 45 are distinguished. The external rail 45 constitutes a distal end of the ring 40 considered along the axis of revolution thereof, and an internal rail 44 beyond which the guide zone 42 extends.The guide zone 42 is mainly represented by a frustoconical wall 46 delimited by a first circular end of reduced diameter and by a second circular end of enlarged diameter, the diameter of the first end being less than that of the second end. These two ends are to be considered along the axis of revolution of the ring 40, the first end being in contact with the internal rail 44 and the second end constituting a distal end of the ring 40.
[0037] Referring to Figures 3, 4, 5 and 7, the guide ring 40 is placed in the enlarged opening 12 of the seat structure 2, so that an annular wall of said seat structure 2 delimiting said enlarged opening 12, is inserted into the external groove 43 of the fixing zone 41 of said ring 40, between the two rails 44, 45.
[0038] A method of attaching the backrest structure 3 to the seat structure 2, or vice versa, comprises the following steps: - a step of fixing the guide ring 40 in the enlarged opening 12 of the seat structure 2, under the conditions defined above, - a step of aligning the enlarged opening 12 provided with the ring 40 with the tapped hole 22 of the nut 21 of the backrest structure 3, this alignment step consisting of aligning as precisely as possible the axis of revolution of said tapped hole 22 with the axis of revolution of said enlarged opening 12, - a step of introducing the threaded rod 31 into the tapped hole 22 of the nut.
[0039] If the tapped hole 22 is perfectly aligned with the enlarged opening 12, the guide ring 40 has no specific function and the threaded rod 31 of the screw 30 is screwed into the tapped hole 22, until the flared section 32 comes into contact with the frustoconical wall 46 of the guide zone 42.
[0040] If the tapped hole 22 is eccentric relative to the enlarged opening 12, the fixing method continues with the following steps: -a step of screwing the screw 30 into the nut 21 causing the flared section 31 of said screw 30 to come into contact with the frustoconical wall 46 of the guide zone 42 of the ring 40, as illustrated in [Fig.3], -a step of continuing the screwing causing the flared section 32 to slide along the truncated cone-shaped wall 46 and therefore a relative movement between the seat structure 2 and the backrest structure 3 allowing the enlarged opening 12 to begin its re-centering on the tapped hole 22, as illustrated in [Fig.4], - a step of continuing then stopping the screwing when the enlarged opening 12 is perfectly centered on said tapped hole 22, as illustrated in figures 5 and 7.
[0041] The guide ring 40 makes it possible to move the seat structure 2 relative to the backrest structure 3, during the screwing phase, so as to correctly position said structures 2, 3 relative to each other and to ensure optimized fixing of these structures 2, 3.
[0042]
Claims
Claims
1. Method for fixing a first structure (2) to a second structure (3) by means of a screw (4, 5, 30) having a cylindrical threaded rod (31) and a flared cylindrical section (32) whose diameter is greater than that of the threaded rod (31), the second structure (3) having a nut (21) comprising a tapped hole (22) intended to receive the threaded rod (31) of the screw (3, 4, 30) and the first structure (2) having an enlarged opening (12) of circular shape, characterized in that it comprises the following steps: - a step of fixing a ring (40) having a funnel-shaped guide zone (42) in the enlarged opening (12) of the first structure (2), - a step of aligning the enlarged opening (12) provided with the ring (40), with the tapped hole (22) of the nut (21) of the second structure (3), - a step of introducing the threaded rod (31) into the tapped hole (22) of the nut (21),-a step of screwing the screw (30) into the nut (21) allowing the flared section (32) to come into contact with the ring (40) in the case where the enlarged opening (12) is not perfectly centered on the tapped hole (22) of the nut (21), -a step of continuing the screwing causing the flared section (32) to press against the ring (40) and therefore a movement of the enlarged opening (12) which tends to refocus on the tapped hole (22) of the nut (21), -a step of stopping the screwing when the enlarged opening (12) is perfectly centered on said tapped hole (22), the flared section (32) coming into contact with the second structure (3).,
2. Fixing method according to claim 1, characterized in that the guide zone (42) of the ring (40) is delimited by an enlarged upstream opening and by a reduced-size downstream opening, and in that the step of introducing the threaded rod (31) into the tapped hole (22) of the nut (21) of the second structure (2), is preceded by a step of passing said threaded rod (31) first into the enlarged upstream opening of the guide zone (42) of the ring (40) then into the reduced-size downstream opening of said ring (40).
3. A method of fixing according to any one of claims 1 or 2, characterized in that the first structure is a seat structure (2) of a vehicle seat or bench, and in that the second structure is a backrest structure (3) of said seat or said seat.
4. Guide ring (40) for carrying out a fixing method according to any one of claims 1 to 3, characterized in that it comprises a funnel-shaped guide zone (42) and a fixing zone (41) having an annular peripheral groove (43) intended to receive an annular zone of the first structure (2) delimiting the enlarged opening (12).
5. Guide ring according to claim 4, characterized in that the annular peripheral groove (43) of the fixing zone (41) is delimited by two circular rails (44, 45) parallel to each other, between which the annular zone of the first structure (2) delimiting the enlarged opening (12) is intended to be inserted.
6. Guide ring according to any one of claims 4 or 5, characterized in that the guide zone (42) extends the fixing zone (41) and is in the form of a frustoconical wall (46).
7. Guide ring according to claim 6, characterized in that the frustoconical wall (46) is delimited along its axis of revolution by a first circular end of reduced diameter and by a second circular end of enlarged diameter, and in that said frustoconical wall (46) is connected to the fixing zone (41) by said first circular end.
8. Guide ring according to any one of claims 6 or 7, characterized in that the frustoconical wall (46) has a smooth internal surface.
9. Guide ring according to any one of claims 4 to 8, characterized in that it is made of plastic.
10. Assembly of a first structure (2) comprising an enlarged opening (12) and a ring (40) having a funnel-shaped guide zone (42) and fixed in said enlarged opening (12), for carrying out a fixing method according to any one of claims 1 to 3.