Stop systems for direct contact heating tools

Abstract

A stop system (1) intended to cooperate with a direct contact heating tool for a plastic welding machine for welding a component to an opening in a wall of a motor vehicle tank, the system comprising a cam mechanism comprising: a straight cam (2) having a longitudinal axis X; at least one follower (3) coupled to the straight cam (2) to convert a translational movement of the at least one follower (3) along the longitudinal axis X into a translation of at least one point of the at least one follower (3) in a direction not parallel to the longitudinal axis X. Upward linear or quasi-linear movement; in the cam mechanism, the at least one follower (3) can be switched from a rest position to a working position, in which the stop system (1) is constructed to freely pass through an opening (10) in a wall (11) of a motor vehicle tank (12), and in which the stop system (1) is constructed to bear against an inner surface (13) of the wall (11) of the tank (12) passed by the straight cam (2), the inner surface (13) being adjacent to the opening (10).

Description

Technical Field

[0001] The present invention relates to a stop system intended to cooperate with a heating tool of direct contact type. More specifically, the present invention relates to a stop system intended to cooperate with a heating tool of direct contact type and used in a welding machine for plastic welding of a component on an opening in a tank wall of a motor vehicle.

[0002] The invention also relates to a direct contact heating assembly.

[0003] The invention also relates to a component plastic welding machine.

[0004] The invention also relates to a method of cooperation which allows a stop system to cooperate with a direct-contact heating tool.

[0005] The invention also relates to a direct contact heating method.

[0006] Finally, the invention relates to a method for plastic welding of components. Background Art

[0007] It is known to use a direct contact heating tool, such as a hot plate, to soften and melt the portion of a first component made of plastic to which a second component is to be welded. The portion of the first component heated by the direct contact heating tool to be softened and melted is called the welding surface. When the first component is, for example, a hollow plastic body obtained by extrusion-blow molding, such as a motor vehicle tank, and the second component is a component that passes through an opening provided in the wall of the hollow plastic body, such as a solenoid valve, the direct contact heating tool must contact the edge of the opening and apply a contact pressure thereto.

[0008] Compared with the same hollow plastic body obtained by injection molding, the wall of the hollow plastic body obtained by extrusion-blow molding is thinner. Thin walls are particularly sensitive to bending, and the larger the surface area of ​​the wall, the easier it is to deform. Therefore, the problem of applying contact pressure on the edge of the opening is its bending deformation. In fact, the bending deformation of the edge of the opening during its heating by the direct contact heating tool tends to make the welding surface break away from the direct contact heating tool, which causes the welding surface to be heated unevenly. The uneven heating of the welding surface may affect the welding quality of the second component on the first component. When the first component is a motor vehicle tank and the second component is a component that passes through the tank like a solenoid valve, the bad welding of the second component on the first component can increase the risk that the tank has a sealing defect. Summary of the invention

[0009] The object of the present invention is in particular to remedy the above-mentioned drawbacks by proposing a stop system which ensures uniform heating of the welding surfaces of the components which may bend under the action of a direct contact heating tool.

[0010] To this end, the subject of the invention is a stop system intended to cooperate with a direct contact heating tool for a plastic welding machine for plastic welding a component on an opening in a wall of a motor vehicle tank, the system comprising a deployable element comprising:

[0011] - an elongated element having a longitudinal axis X, selected from the following list: a straight cam, a rack, a worm, an inflatable ball;

[0012] at least one follower coupled to the extension element to convert the translational movement of the at least one follower along the longitudinal axis X into a linear or quasi-linear movement of at least one point of the at least one follower in a direction not parallel to the longitudinal axis X;

[0013] In the deployable element, the at least one follower can be switched from a rest position, in which the stop system is configured to freely pass through an opening in a wall of a motor vehicle tank, to an operating position, in which the stop system is configured to bear against an inner surface of the wall of the tank through which the extension element passes, said inner surface being adjacent to the opening in the tank wall.

[0014] As a result, the stop system prevents the tank wall from bending when the direct-contact heating tool exerts contact pressure on the edge of the opening.

[0015] "Plastic welding" refers to a collection of techniques used to weld two parts made of thermoplastic materials.

[0016] "Passing freely" means passing through the tank wall without contact with the tank wall.

[0017] A "straight cam" refers to a cam in which the section coupled to at least one follower is straight.

[0018] It is recalled that the tank wall has an inner surface and an outer surface. The inner surface is the surface facing the inner volume of the tank, while the outer surface is the surface facing the outer volume of the tank. Thus, when the stop system passes through the opening in the tank wall, the deployable element is completely in the inner volume of the tank and stays therein when the at least one follower element is transferred from the rest position to the working position and vice versa.

[0019] "Straight or quasi-straight line" means that the movement of at least one point of the at least one follower generally describes a straight line segment, rather than an arc.

[0020] By means of the invention, when the at least one follower is transferred from the rest position to the working position, each point of the at least one follower describes a straight line segment in the internal volume of the tank. This allows the transfer from the rest position to the working position to be made by a single movement resulting from a single action of the deployable element. With this arrangement, the transfer from the rest position to the working position is simplified and the time required for this transfer is shortened.

[0021] Additional technical features of the system according to the invention:

[0022] The abutment of the stop system on the inner surface of the tank wall is selected from planar abutment, linear abutment and point abutment. The planar abutment provides better support for the tank wall against deformation when the direct contact heating tool exerts contact pressure on the edge of the opening.

[0023] - the extension element is a straight cam, the coupling of the at least one follower to the straight cam being achieved by direct contact between the first peripheral surface of the at least one follower and a planar coupling surface of the straight cam inclined at a non-zero angle A relative to the longitudinal axis X thereof, forcing the first peripheral surface of the at least one follower to follow the planar coupling surface of the straight cam, causing the at least one follower to perform both a translational movement along the longitudinal axis X and a rotational movement around an axis of rotation Y perpendicular to the longitudinal axis X when the at least one follower is transferred from a rest position to operation. Thus, the linear or quasi-linear movement of at least one point of the at least one follower in a direction not parallel to the longitudinal axis X results from the combination of two mutually dependent movements: the translational movement of the at least one follower and the rotational movement of the at least one follower. These two movements are mutually dependent because one cannot be achieved without the other.

[0024] "Direct contact" refers to contact with friction.

[0025] - The first peripheral surface is a rounded surface, thereby reducing friction.

[0026] Angle A is between 10° and 15°, preferably angle A is equal to about 10°. Angle A is the angle formed between a straight line carried by the longitudinal axis X and its orthogonal projection on a plane coinciding with the planar coupling surface.

[0027] The extension element is a straight cam, and the second peripheral surface of the at least one follower is configured to bear against the inner surface of the tank wall traversed by the straight cam in the working position. Thus, the at least one follower prevents deformation of the tank wall.

[0028] The abutment of the second peripheral surface of the at least one follower on the inner surface of the tank wall is selected from a planar abutment, a linear abutment and a point abutment. The planar abutment provides better support for the tank wall against deformation when the direct contact heating tool applies contact pressure on the edge of the opening.

[0029] The extension element is a straight cam, the at least one follower comprises a rotary shaft with axis Y, mounted in a housing of a cylindrical support with longitudinal axis X, the cylindrical support being axially displaceable relative to the straight cam along the longitudinal axis X, so as to convert the translational movement of the at least one follower along the longitudinal axis X into a linear or quasi-linear movement of at least one point of the at least one follower. With this arrangement, the at least one follower is forced to move in tandem with the straight cam.

[0030] Advantageously, the follower is a non-deformable follower, in which case the translational movement of the at least one follower along the longitudinal axis X is converted into a linear or quasi-linear movement of each point of the at least one follower. The points of the at least one follower lying on the axis Y are displaced in a direction parallel to the longitudinal axis X, while the points not lying on the axis Y are displaced linearly in a direction not parallel to the longitudinal axis X.

[0031] The deployable element comprises n followers, wherein n is an increasing function of the size of the opening. Thus, the larger the size of the opening, the more followers are provided to support the tank wall against deformation thereof when the direct contact heating tool exerts a contact pressure on the edge of the opening. Advantageously, the n followers are arranged equidistantly on the inner surface of the wall adjacent to the edge of the opening.

[0032] Preferably, n is greater than or equal to three. Thus, the abutment of the stop system on the inner surface of the tank wall is a statically determinate abutment.

[0033] Preferably, n is greater than or equal to 4. Thus, the abutment of the stop system on the inner surface of the tank wall is a hyperstatic abutment.

[0034] The invention also relates to a direct contact heating assembly for a plastic welding machine for welding a component to an opening in a tank wall of a motor vehicle, comprising a direct contact heating tool and a stop system as described above, whereby the heating assembly prevents the tank wall from bending when the welding surface is heated.

[0035] According to additional technical features of the direct contact heating assembly according to the invention:

[0036] - The direct contact heating tool comprises a molten material overflow limiter, thereby preventing molten plastic from overflowing into the opening when the welding surface is heated.

[0037] The molten material overflow limitation element is coupled to the direct contact heating tool, for example by means of a fastening flange. Thus, the molten material overflow limitation element and the direct contact heating tool form an assembly.

[0038] The subject of the invention is also a plastic welding machine for welding a component to an opening in a tank wall of a motor vehicle, the machine comprising a heating assembly as described above and an assembly tool for assembling the component by plastic welding. The plastic welding machine thus improves the welding quality of the component on the tank.

[0039] The subject of the invention is also a method of cooperation which allows the above-mentioned stop system to cooperate with a direct contact heating tool for a plastic welding machine for welding a component on an opening in a tank wall of a motor vehicle, the method comprising the following steps:

[0040] - placing the at least one follower in a rest position;

[0041] - Insert the stop system through the opening;

[0042] - bringing the direct contact heating means into direct contact with the outer surface of the wall of the tank adjacent to the opening;

[0043] - Placing the at least one driven element in an operating position.

[0044] The outer surface of the wall of the tank adjacent to the opening is the welding surface. Thus, the cooperation method prevents the contact pressure of the direct contact heating tool from deforming the tank wall.

[0045] According to the additional technical features of the cooperation method according to the present invention:

[0046] - Before the step of placing the at least one follower in the working position, a step of bringing the direct contact heating tool into direct contact with the outer surface of the wall of the tank adjacent to the opening is performed. Thus, the heating of the welding surface is achieved as early as possible, which allows to shorten the production time of the tank.

[0047] After the step of placing the at least one follower in the working position, a step of bringing the direct contact heating means into direct contact with the outer surface of the wall of the tank adjacent to the opening is performed, whereby deformation of the wall is prevented from the start of heating.

[0048] - Simultaneously with the step of placing the at least one follower in the working position, a step of bringing the direct contact heating tool into direct contact with the outer surface of the wall of the tank adjacent to the opening is performed. Thus, the welding surface is heated as early as possible and deformation of the wall is prevented from the beginning of heating.

[0049] The subject of the invention is also a direct contact heating method for heating a tank wall of a motor vehicle by direct contact with a direct contact heating tool, comprising the steps of the above-described method and a step of heating the outer surface of the tank wall adjacent to the opening by direct contact with the direct contact heating tool, thereby preventing the tank wall from bending while the direct contact heating tool heats the welding surface.

[0050] Finally, the subject of the invention is a plastic welding method for welding a component to an opening in a tank wall of a motor vehicle, comprising the steps of the above-described heating method and the following steps:

[0051] - placing the at least one follower in a rest position;

[0052] - remove the stop system from the opening;

[0053] - Separating the direct contact heating tool from the opening;

[0054] - Weld the components over the openings.

[0055] The plastic welding method thus allows the quality of the welding of the component to the tank to be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The invention will be better understood from the following description given by way of example only and made with reference to the accompanying drawings, in which:

[0057] - Figure 1 A partial perspective view of a plastic welding machine according to the present invention;

[0058] - Figures 2 to 5 is a cross-sectional view of a stop system according to the present invention;

[0059] - Figure 6 is a sectional view of an embodiment variant of the stop system according to the present invention. DETAILED DESCRIPTION

[0060] Figure 1 A plastic welding machine 40 is shown for welding a component 100 on an opening 10 in a wall 11 of a tank 12 of a motor vehicle (not shown). The plastic welding machine 40 comprises a heating assembly 20 and an assembly tool 50 for assembling the component 100 by plastic welding. The heating assembly 20 comprises a direct contact heating tool 30 and a stop system 1 according to the invention. The stop system 1 is in an initial position and is completely in the outer volume of the tank 12.

[0061] Figures 2 to 4 The stop system 1 is shown in a final position in which it is completely located in the inner volume of the tank 12 and cooperates with the direct-contact heating tool 30 .

[0062] Figure 5 The stop system 1 is shown in an intermediate position between the initial position and the end position. In this intermediate position, the stop system 1 is passing through the opening 10.

[0063] like Figures 2 to 5 As shown, the stop system 1 comprises a deployable element, which comprises an extension element 2 with a longitudinal axis X, here constituted by a straight cam 2, and at least one follower 3, which is coupled to the straight cam 2 so as to convert the translational movement of the at least one follower 3 along the longitudinal axis X into a linear or quasi-linear movement of at least one point of the at least one follower 3 in a direction not parallel to the longitudinal axis X. The deployable element here forms a cam mechanism, i.e. a mechanism by which a displacement of the cam causes a different and reversible displacement of the one or more followers coupled to the cam. The at least one follower 3 can be transferred from a rest position, in which the stop system 1 is configured to freely pass through an opening 10 in a wall 11 of a tank 12 of a motor vehicle, to an operating position, in which the stop system 1 is configured to bear against an inner surface 13 of the wall 11 of the tank 12, which is penetrated by the cam 2, and which is adjacent to the opening 10.

[0064] Ideally, the at least one follower 3 is coupled to the straight cam 2 through direct contact between the first outer peripheral surface 4 of the at least one follower 3 and a planar coupling surface 5 of the straight cam 2 which is inclined at a non-zero angle A relative to the longitudinal axis X direction thereof, so as to force the first outer peripheral surface 4 of the at least one follower 3 to follow the planar coupling surface 5 of the straight cam 2, resulting in that when the at least one follower 3 is converted from the rest position to the working position, the at least one follower 3 performs both translational motion along the longitudinal axis X and rotational motion around the rotation axis Y which is perpendicular to the longitudinal axis X.

[0065] In the working position, the second peripheral surface 6 of the at least one follower 3 is configured to bear against the inner surface 13 of the wall 11 of the tank 12 pierced by the straight cam 2 .

[0066] Advantageously, the at least one follower 3 comprises a rotation axis of axis Y mounted in a housing of a cylindrical support 7 having a longitudinal axis X (see Figure 5 ), the cylindrical support 7 is capable of axially shifting along the longitudinal axis X relative to the straight cam 2 to convert the translational motion of the at least one follower 3 along the longitudinal axis X into a linear motion or quasi-linear motion of at least one point of the at least one follower 3.

[0067] Preferably, the deployable element comprises n followers 3, wherein n is a function that increases with the size of the opening. In the example shown, n is equal to six.

[0068] Advantageously, the six followers are arranged equidistantly on the inner surface 13 of the wall 11 adjacent to the edge of the opening 10 .

[0069] Figures 1 to 5 A method of cooperating the stop system 1 with the direct contact heating tool 30 is also shown. The method of cooperating comprises the following steps:

[0070] - placing the at least one follower 3 in a rest position (see Figure 1 );

[0071] - Insert the stop system 1 through the opening 10 (see Figure 5 );

[0072] - direct contact heating means 30 is brought into direct contact with the outer surface 14 of the wall 11 of the tank 12 adjacent to the opening 10 (see Figure 2 );

[0073] - placing the at least one follower 3 in the working position (see Figure 4 ). Figure 3 An intermediate position of the at least one driven element 3 is shown when switching from the rest position to the working position.

[0074] Preferably, before placing the at least one follower 3 in the working position, a step of bringing the direct contact heating means 30 into direct contact with the outer surface 14 of the wall 11 of the tank 12 adjacent to the opening 10 is carried out.

[0075] Figures 1 to 5 Also shown is a direct contact heating method comprising the steps of the above described cooperating method and a direct contact heating step of heating the outer surface 14 of the wall 11 of the tank 12 adjacent to the opening 10 in direct contact with a direct contact heating tool 30 .

[0076] at last, Figures 1 to 5 A plastic welding method is shown, which includes the steps of the above heating method and the following steps:

[0077] - placing the at least one follower 3 in a rest position;

[0078] - removing the stop system 1 from the opening 10;

[0079] - Separating the direct contact heating tool 30 from the opening 10;

[0080] The component 100 is welded to the opening 10 .

[0081] Figure 6 An embodiment variant is shown in which the direct contact heating tool 30 comprises a molten material escape restriction.

[0082] Ideally, the molten material overflow limiter 8 is coupled to the direct contact heating tool 30 , for example by means of a fastening flange 9 .

[0083] According to a variant embodiment of the invention, the straight cam of the deployable element is replaced by one of the elements in the following list: rack, worm, inflatable ball. The operation of the stop system remains similar to that described above.

[0084] List of Reference Numerals

[0085] 1: Stop system

[0086] 2: Extension element / straight cam

[0087] 3: Follower

[0088] 4: The first peripheral surface of the follower

[0089] 5: Flat coupling surface of straight cam

[0090] 6: Second peripheral surface of the follower

[0091] 7: Column support

[0092] 8: Molten material overflow limiter

[0093] 9: Fastening flange

[0094] 10: Openings in the tank wall of motor vehicles

[0095] 11: Motor vehicle tank wall

[0096] 12: Motor vehicle tanks

[0097] 13: Inner surface of the tank wall through which the straight cam passes

[0098] 14: The outer surface of the wall of the tank through which the straight cam passes

[0099] 20: Direct contact heating element

[0100] 30: Direct contact heating tool

[0101] 40: Plastic welding machine

[0102] 50: Component assembly tool

[0103] 100: Components to be welded

Claims

1. A stop system (1) intended to cooperate with a direct contact heating tool of a plastic welding machine for plastic welding a component on an opening in a wall of a tank of a motor vehicle, the system comprising a deployable part comprising: - an extension element (2) having a longitudinal axis X, which is a straight cam; - at least one follower (3) coupled to the extension element (2) to convert the translational movement of the at least one follower (3) along the longitudinal axis X into a linear or quasi-linear movement of at least one point of the at least one follower (3) in a direction not parallel to the longitudinal axis X; In the deployable element, the at least one follower (3) is transferable from a rest position, in which the stop system (1) is configured to freely pass through an opening (10) in a wall (11) of a tank (12) of a motor vehicle, to an operating position, in which the stop system (1) is configured to bear in a planar manner against an inner surface (13) of the wall (11) of the tank (12) through which the extension element (2) passes, the inner surface (13) being adjacent to the opening (10), The at least one follower (3) is coupled to the straight cam (2) by direct contact between the first peripheral surface (4) of the at least one follower (3) and the planar coupling surface (5) of the straight cam (2) which is inclined at a non-zero angle A relative to the longitudinal axis X direction of the straight cam (2), so as to force the first peripheral surface (4) of the at least one follower (3) to follow the planar coupling surface (5) of the straight cam (2). When the at least one follower (3) is converted from the rest position to the working position, the at least one follower (3) performs both translational movement along the longitudinal axis X and rotational movement around a rotation axis Y which is perpendicular to the longitudinal axis X.

2. The stop system according to claim 1, wherein: The second peripheral surface (6) of the at least one follower (3) is configured to bear against the inner surface (13) of the wall (11) of the tank (12) through which the straight cam (2) passes, in the working position.

3. The stop system according to any one of claims 1 to 2, wherein: The at least one follower (3) comprises a rotating shaft having an axis Y, which is mounted in a housing of a cylindrical support (7) having a longitudinal axis X, wherein the cylindrical support (7) is axially displaceable relative to the straight cam (2) along the longitudinal axis X so as to convert the translational movement of the at least one follower (3) along the longitudinal axis X into a linear movement or a quasi-linear movement of at least one point of the at least one follower (3).

4. The stop system according to any one of claims 1 to 2, wherein: The deployable member comprises n followers (3), wherein n increases as the size of the opening increases.

5. A direct contact heating assembly (20) for a plastic welding machine for welding a component to an opening in a tank wall of a motor vehicle, the assembly comprising a direct contact heating tool (30) and a stop system (1) as claimed in any one of claims 1 to 4.

6. The heating assembly (20) according to claim 5, wherein: The direct contact heating tool (30) comprises a molten material overflow limiting member (8).

7. The heating assembly (20) of claim 6, wherein: The molten material overflow limiting member (8) is connected to the direct contact heating tool (30).

8. A plastic welding machine (40) for welding a component to an opening in a tank wall of a motor vehicle, the machine comprising a heating assembly (20) as claimed in any one of claims 5 to 7 and an assembly tool (50) for assembling the component (100) by plastic welding.

9. A method of cooperation, which allows a stop system (1) according to any one of claims 1 to 4 to cooperate with a direct contact heating tool (30) for a plastic welding machine for welding a component on an opening (10) in a wall (11) of a tank (12) of a motor vehicle, the method comprising the following steps: - placing said at least one follower (3) in said rest position; - passing the stop system (1) through the opening (10); - bringing the direct contact heating means (30) into direct contact with the outer surface (14) of the wall (11) of the tank (12) adjacent to the opening (10); - Placing the at least one follower (3) in the working position.

10. The collaborative method according to claim 9, wherein: Prior to the step of placing the at least one follower (3) in the working position, a step of bringing the direct contact heating tool (30) into direct contact with the outer surface (14) of the wall (11) of the tank (12) adjacent to the opening (10) is implemented.

11. A direct contact heating method for heating a tank wall of a motor vehicle by direct contact with a direct contact heating tool, comprising the steps of the cooperative method as claimed in any one of claims 9 to 10 and a heating step of heating the outer surface (14) of the wall (11) of the tank (12) adjacent to the opening (10) by direct contact with the direct contact heating tool (30).

12. A plastic welding method for welding a component to an opening in a tank wall of a motor vehicle, comprising the steps of the heating method according to claim 11 and the following steps: - placing said at least one follower (3) in said rest position; - removing the stop system (1) from the opening (10); - separating the direct contact heating tool (30) from the opening (10); - Welding the component (100) to the opening (10).

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