Plastics fasteners

Abstract

A latch unit formed in one-piece of a resiliently flexible plastics material and comprising two body portions which are hinged to one another, and which are further hinged to a latch and a button respectively, the arrangement being such that the body portions can be folded to a position in which they can be inserted into and held by an aperture in a panel, manual actuation of the button then causing movement of the latch from an operative position to an inoperative position.

Description

This invention concerns latch units, and has as its object the avoidance of the twin problems of complex manufacture and assembly associated with known latch units formed from numerous metal components.

According to the present invention, a latch unit is formed in one-piece of a resiliently flexible plastics material and comprises two body portions which are hinged to one another, and which are further hinged to a latch and a button respectively, the arrangement being such that the body portions can be folded to a position in which they can be inserted into and held by an aperture in a panel, manual actuation of the button then causing movement of the latch from an operative position to an inoperative position.

Preferably, the body portions in their folded position define a hollow generally elongate body, with the latch being generally parallel to the axis, the button being generally perpendicular thereto and at least partially closing one end of said hollow body, and the latch and the button directly abutting one another.

Such a preferred latch unit can be readily applied to, for example, a spring-biased door of an automobile glove box. When the button is pressed, the latch will be moved thereby to its inoperative position (in which it no longer acts as a stop) thus allowing the glove box door to spring open.

A latch unit according to the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a latch unit in its as-moulded position;

FIG. 2 is a longitudinal section taken along the centre of FIG. 1, as indicated by the arrows II--II seen in FIG. 1, the latch unit having been folded to a position suitable for application to a glove box door; and

FIG. 3 is a perspective view of merely a portion of the latch unit looking at the left-hand end of FIG. 1.

Throughout this description it is to be understood that the latch unit is perfectly symmetrical about the longitudinally-extending plane II--II.

The latch unit in accordance with the present invention is a one-piece plastics moulding which has two flanges 10 and 12 for abutting one face of an apertured panel, at least one resiliently flexible barb for abutting the other face of the apertured panel, a hinge portion 14, a latch 16 having an oblique cam surface 18, and a button 20 having an oblique cam surface 22. The material of the moulding is itself chosen to be resiliently flexible. A suitable material is nylon 6.

Between the flange 10 and the hinge 14 is a hollow frusto-conical body portion 24 which is semi-circular in end elevation; similarly-shaped body portion 26 lies between the flange 12 and the hinge 14. The two body portions increase in cross-section from the hinge to the flanges. The latch 16 is hinged to the body portion 24, the button 20 being hinged to the body portion 26 by a hinge portion 32. Projecting radially-outwards from the frusto-conical surfaces are barbs 28 and 30, each of which is defined on three sides by a gap so that it can be resiliently flexed in a radially-inwards direction.

From the as-moulded position seen in FIG. 1, the latch unit is assembled by folding the body portion 26 downwards and towards the viewer, turning through 180.degree. in an anti-clockwise sense to meet the body portion 24. Just before meeting, the button 20 is pressed ahead of the body portion 26 so as to pass between the flange 10 and the latch 16, as shown in FIG. 2. In their folded position, the body portions 24 and 26 define a hollow generally elongate body, with the latch 16 being generally parallel to the axis, the button 20 being generally perpendicular thereto and at least partially closing one end of said hollow body, and the cam surfaces 18 and 22 formed on the latch 16 and the button 20 respectively directly abutting, and thereby co-operating with one another. The latch 16 and the button 20 are prevented from becoming separated from one another, when the body portions 24 and 26 are in their above-described folded position, by a stepped shoulder 31 formed on the button 20 which can engage with the body portion 24 behind the flange 10. Flexing of the button 20 towards the far end of the hollow body is, however, still allowed by the hinge portion 32.

The shaping and dimensioning are such that when the two flanges 10 and 12 meet one another, the cam surface 22 has ridden-up the cam surface 18 and the latch 16 has been slightly biased in a clockwise sense relatively to the hinge 14. In its folded position the latch unit can be pressed into an aperture in a panel, such as a glove box door (not shown). On application to the door, the hinge 14 leads through the aperture, then the latch 16 is flexed resiliently inwards by engagement with the aperture edge, and finally the barbs 28 and 30 are similarly temporarily depressed. The aperture diameter and the door thickness are chosen so that the door can be firmly gripped between the barbs and the adjacent flanges. The latch unit can thus be held in the condition seen in FIG. 2.

A wall of the dashboard compartment (not shown) to which the glove box door is hinged, has a portion which abuts the latch 16 to hold the door shut when the latch 16 is in its operative position shown in FIG. 2. Subsequent depression of the button 20, by manual actuation, causes the cam surfaces 22 and 18 to ride over one another to urge the latch 16 downwards, as viewed, towards its inoperative position in which it no longer acts as a stop. That is to say, depression of the button 20 forces the latch 16 downwards, releasing it from abutment with the dashboard wall, and permitting the glove box door to open.

Clearly, there are many other applications in which the present inventive latch unit can be used to advantage.

Claims

I claim:

1. A latch unit formed in one-piece of a resiliently flexible plastics material and comprising two body portions which are hinged to one another, and which are further hinged to a latch and a button respectively, the arrangement being such that the body portions can be folded to a position in which they can be inserted into and held by an aperture in a panel, manual actuation of the button then causing movement of the latch from an operative position to an inoperative position.

2. A latch unit according to claim 1, in which the body portions in their folded position define a hollow generally elongate body, with the latch being generally parallel to the axis, the button being generally perpendicular thereto and at least partially closing one end of said hollow body, and the latch and the button directly abutting one another.

3. A latch unit according to claim 2, in which the button is formed with a stepped shoulder which can engage with that body portion carrying the latch to prevent the latch and the button becoming separated from one another when the body portions are in their folded position.

4. A latch unit according to claim 1, in which the body portions are semi-circular in end elevation and symmetrical about a longitudinally-extending plane.

5. A latch unit according to claim 4, in which each of the body portions is frusto-conical, their cross-sections increasing with increased distance from the hinge by which they are connected.

6. A latch unit according to claim 1, in which each of the body portions is formed with a flange for abutting one face of the apertured panel.

7. A latch unit according to claim 6, in which each of the body portions is formed with at least one resiliently flexible barb for abutting the other face of the apertured panel.

8. A latch unit according to claim 1, in which co-operating oblique cam surfaces are formed on both the button and the latch.