Device for fixing a plastic part on a body shell structure

Abstract

The invention concerns a device for fixing a plastic part (4) on a body shell structure, comprising a plate (1), mobile in an opening provided in the plastic part and elastic means (2) for returning, along the longitudinal axis, the plate (1) into the opening. The invention is characterized in that the slot (3) provided in the plastic part comprises at least on one of its sides, a slanting stop (5) which co-operates with the elastic means (2).

Description

The invention relates to a device for fixing a plastic fender on the body of a vehicle.

More particularly, it relates to a device for fixing a plastic fender whose coefficient of expansion is greater than that of the support to which it is attached.

During fixation of plastic fenders to bodies, it is necessary to allow for the different natures of the materials assembled, because they can react in very different ways under certain temperature conditions. Their assembly must not be accomplished to the detriment of one of them, which would be at risk of deterioration. This is particularly true during a cataphoresis treatment, in which the plastic fender undergoes much greater expansion than the body structure. The fixation devices must then provide space for displacement of the plastic fender.

At present, the devices for fixation of a plastic fender may be composed of a plate to be placed in an opening known as a slot, provided for the purpose. The plate is able to slide longitudinally into this slot as a function of the displacement of the fender relative to the body structure, and elastic means are provided for retracting the plate into its initial position. However, these devices limit the expansion of the plastic fender to the length of the slot created therein.

French Patent 2747091 describes a sliding fixation device for a plastic fender wherein elastic means cooperate with the fixation element in an equilibrium position, in such a way that the clearance of the element is limited by the borders of the slot. In addition, the forces exerted against the plate during expansion are so large than they can block the spring element.

To this end, the invention relates to a device for fixation of a plastic part on a body structure, the device comprising a plate that can move in an opening created in the plastic fender and an elastic means with which the plate can be retracted along the longitudinal axis into the opening.

According to one characteristic of the invention, the slot created in the plastic part is provided at least on one of its widths with an oblique stop that cooperates with the elastic means.

According to another characteristic, the elastic means is a spring.

According to another characteristic, the length of the opening provided for sliding of the plate is at least equal to the length of the plate plus the expansion distance.

According to another aspect of the invention, the recesses intended to receive the projections of the plate define the lower and upper limits of the stop.

Another characteristic is that the spring, when in rest position, is affixed on that side of the stop whose base defined by the recesses is the broadest.

Other characteristics and advantages of the invention will become evident upon reading the description of practical examples of a device for fixation of a plastic part to the body structure in the attached drawings, wherein:

FIG. 1 illustrates a front view of the plate inserted in the slot in normal position, with the spring compressed under minimal load.

FIG. 2 illustrates the position of the plate when the plastic fender has undergone expansion due to a temperature change.

FIG. 1 corresponds to the equilibrium position of plate 1 when it is not being subjected to any treatment capable of deforming it. Spring 2 exerts a maintaining force between the plate and the contour of slot 3 of plastic fender 4. Spring 2 is braced at one of its ends on plate 1 and at its other end on the edge of the slot formed by an oblique stop 5. The length of slot 3 is at least equal to that of plate 1 plus that of the expansion distance during cataphoresis treatments or during exposure to strong sunlight.

Furthermore, the width of plate 1 is adapted to that of slot 3 in such a way as to slide therein without jamming. The sliding is guided by the longitudinal edges of the slot, which are the supports of the groove of the movable plate. For one of the grooves, the only function is to permit sliding; the other groove is a notch formed by the toe, and it has the additional function of introducing the plate into the slot.

During manufacture, the spring and the plate are made in the same mold, into which the screw is inserted. After the product has been injected, a cooling time is necessary in order to eject the molded article. To this end, the plate is provided with four projections 6, two of which are shown. By means of these projections, the part can be thrust out of the mold without suffering deformation, even though it is still fragile. Recesses 7, intended to receive projections 6 of the plate when the fender has been subjected to expansion, are made in the slot. They define the lower and upper limits of the edges of stop 5. Furthermore, the projections add a guiding and stabilizing length during expansion of the part.

When the device is in rest position, the spring is compressed under minimal load, and one of its ends is braced on the face of the stop where the base is largest. The spring occupies the space calculated for expansion.

FIG. 2 illustrates the device when the plastic fender is undergoing expansion due to heat.

Spring 2 is in compressed position, and projections 6 of plate 1 have slid into recesses 7 provided for this purpose. Since the spring travel of spring 2 is larger than the length of projections 6 of the plate, this spring necessarily undergoes a vertical translational movement along the stop during compression. Since stop 5 is slanted, spring 2 can eventually be received in the space created by the oblique line of the stop, in such a way that it achieves longer travel as the projections are entering the recesses. During expansion, therefore, the spring becomes retracted at an inclination such that its end does not become jammed under one of the projections.

Claims

1. A device for fixation of a plastic part (4) on a body structure, the device comprising a plate (1) that can move in an opening (3) created in the plastic part, an elastic means (2) permitting the plate (1) to be retracted along the longitudinal axis into the opening, characterized in that the slot (3) created in the plastic part is provided at least on one of its widths with an oblique stop (5) that cooperates with the elastic means (2).

2. A device according to claim 1, characterized in that the elastic means (2) is a spring.

3. A fixation device according to claim 1, characterized in that the length of the opening (3) provided for sliding of the plate (1) is at least equal to the length of the plate and that of the expansion distance.

4. A fixation device according to claim 1, characterized in that the recesses (7) intended to receive the projections (6) of the plate (1) define the lower and upper limits of the stop (5).

5. A fixation device according to claim 1, characterized in that the spring (2), when in minimal load position, is affixed on that side of the stop (5) whose base defined by the recesses is the broadest.