Guide rail, device and method for the injection moulding of this rail

A method of injection moulding of a guide rail of a guide shoe fastened to a sliding window of a motor vehicle door, the guide rail having no draft angles, wherein the guide rail is made from an injected plastic material, wherein the guide rail comprises at least one portion having a shape of a tubular profile, which has a recess over the entire length of the tubular profile and which is provided over at least one portion of the length of the tubular profile with a longitudinal slot and wherein the tubular profile is curved in a shape of an arc of a circle, the arc of a circle being inscribed in a plane, so that an outer surface of the tubular profile has a concave longitudinal zone, an opposite convex longitudinal zone and two opposite lateral longitudinal zones, with each lateral longitudinal zone extending from the concave longitudinal zone to the opposite convex longitudinal zone, and wherein the longitudinal slot extends along one of the two opposite lateral longitudinal zones or along the concave longitudinal zone, wherein the method comprises the steps of:

• providing an injection moulding device comprising:
• a mould comprising a male portion and a female portion together delimiting a moulding cavity the shape of which corresponds to that of a contour of the guide rail to be moulded, the guide rail to be moulded having no draft angles, comprising at least one portion having a shape of a tubular profile, which has a recess over an entire length of the tubular profile and which is provided over at least one portion of the length of the tubular profile with a longitudinal slot, the tubular profile being curved in a shape of an arc of a circle, the arc of a circle being inscribed in a plane, so that an outer surface of the tubular profile has a concave longitudinal zone, an opposite convex longitudinal zone and two opposite lateral longitudinal zones, with each lateral longitudinal zone extending from the concave longitudinal zone to the opposite convex longitudinal zone, and the longitudinal slot extending along one of the two opposite lateral longitudinal zones or along the concave longitudinal zone,
• the female portion of the mould comprising at least two parts, the moulding cavity comprising a moulding cell with two ends, the shape of which corresponds to that of the at least one portion of the guide rail having the shape of the tubular profile,
• the male portion of the mould comprising at least one core for the formation of the recess of the guide rail and an intermediate part for the formation of the longitudinal slot of the guide rail, the core being curved in the shape of an arc of a circle inscribed in a plane,
• a device for injecting under pressure inside the moulding cavity, plastic material configured to manufacture the guide rail, and
• an extraction device for extracting the at least one core of the male portion outside the moulding cell of the mould, the extraction device being configured to displace the core from one of the two ends of the moulding cell in a trajectory of an arc of a circle of the same radius as a radius of the arc of a circle of the core in order to extract the core from one of the two ends of the moulding cell,
• injecting at least one plastic material under pressure inside the moulding cavity of the mould of the injection moulding device,
• hardening the at least one plastic material,
• actuating the extraction device to slide the male portion of the mould outside the female portion of the mould to extract the male portion from the female portion;
• and
• separating the at least two parts of the female portion of the mould to unmould the guide rail thus obtained.