EP0085336B1 - Reflector for a street lamp - Google Patents

Abstract

1. A reflector for a street-lamp, shaped like a hood symmetrical to a main plane (H) and associated with a bulb-shaped lamp (L) whose longitudinal axis is arranged on the intersection line between main plane (H) and a transverse plane (Q) at right angles thereto, and so determines the zero point (O) of a coordinate system (x, y) in a reference plane (B) at right angles to the main and transverse planes, said reflector having two halves which are symmetrical with respect to the main plane (H) and rest against each other in a common limiting curve (KO) and respectively consist of three cup-shaped reflecting zones (1, 2, 3), namely a central reflecting zone (1) and two lateral reflecting zones (2, 3) so arranged that only the light reflected from the central reflecting zone (1) crosses the main plane (H) and the common limiting curve (K1, K2), in which each of the lateral reflecting zones (2, 3) borders on the central reflecting zone (1) in an intersection plane (S2, S3) at right angles to the reference plane (B), characterized in that each reflecting zone (1, 2, 3) is a section from a body of rotation having a rotational axis (M1, M2, M3), at right angles to the reference plane (B), and a generatrix (E1, E2, E3) which at least in the third adjacent to the reference plane (B) approximates a parabolic or circular course, that the intersection planes (S2, S3) together with the transverse plane (Q) form an acute setting angle (alpha 2, alpha 3) of different value and sign between the central reflecting zone (1) and the adjacent lateral reflecting zones (2, 3), that the Y-coordinate of the rotational axis (M1) of the central reflecting zone (1) is negative, and that the following value, within a tolerance of +- 10 %, are valid for the coordinates of the rotational axes (M2, M3) and the rotational radius (r2, r3) of the lateral reflecting zones (2, 3) in the reference plane (B) Reflecting Zone 2 3 X/D 0.28 1.04 Y/D -0.23 1.18 r/D 0.56 1.78 where D, the maxiamal diameter of the reflector in the reference plane (B), lies below 300 mm, and preferably has a value of 220 mm +-5 %.

Description

The invention relates to a reflector for a street lamp according to the preamble of claim 1.

Such a reflector is known from FIGS. 7 and 8 of US Pat. No. 2,612,600 and provides an approximately elliptical Isolux diagram (lines of the same illuminance on the street), which is more suitable for illuminating streets than a circular Isolux diagram.

Such reflectors are used almost exclusively today for illuminating residential streets and pedestrian zones and are arranged at a relatively low height on the street side. For aesthetic reasons, relatively small dimensions are required, which, however, make it very difficult to optimize the lighting technology. This is especially true when lamps with a clogged bulb, i.e. a large luminous surface, are to be used. Under these conditions, the asymmetrical isolux curve mentioned at the outset is difficult to achieve, especially if an additional light band kink, i.e. an asymmetry with respect to the longitudinal axis, is required: Only with such a light band kink can the luminous flux of the luminaires placed on the side move away from the house walls towards the middle of the street to steer.

In the known reflector, an initially rotationally symmetrical glass body is assumed, which after heating is pressed in on two opposite sides to produce the lateral mirror zones. However, this method is not suitable for mass production if certain lighting requirements are to be met with high accuracy. For this purpose, it is necessary to press or cast the reflector material around a correspondingly shaped core matrix in a manner known per se. However, the production of such a core matrix for a dome-shaped asymmetrical reflector is extremely difficult and complex.

The invention is therefore based on the object of developing a reflector according to the preamble of claim 1 in such a way that, given predetermined maximum dimensions in conjunction with a lamp with a clogged bulb, an isolux diagram is obtained which is symmetrical only with respect to an axis running transversely to the longitudinal direction of the street, with additionally the Possibilities of a simple and precise production must be taken into account.

A solution to this problem is the reflector characterized in claim 1.

Since the reflector in the invention consists only of rotating surfaces, the matrix core required for production can be easily produced despite high accuracy, which at the same time ensures cheap and exact series production.

In the case of the invention, the lateral mirror zones are also shaped and arranged substantially differently, which is also expressed in particular in the acute angles of incidence of the cutting planes, based on the transverse plane. The associated inclination of the inner parts of the lateral mirror zones means that the majority of the light rays falling on them leave the reflector without multiple reflections. In contrast, the inner sections of the lateral mirror zones radiate upwards into the reflector in the known case.

Further advantageous embodiments of the invention are characterized in the subclaims.

• Fig. 1 eine Ansicht des Reflektors von oben (in der Bezugsebene B),
• Fig. 2 einen Schnitt entlang Linie 11-11 in Fig. 1,
• Fig. 3 einen Schnittentlang Linie 111-111 in Fig. 1,
• Fig. 4 einen Schnitt entlang Linie IV-IV in Fig. 1,
• Fig. 5 einen Schnitt durch die eine seitliche Spiegelzone 2 entlang Linie V-V in Fig. 1, und
• Fig. 6 einen Schnitt durch die andere seitliche Spiegelzone 3 entlang Linie VI-VI in Fig. 1.

An embodiment of the invention is explained in more detail with reference to the figures; show it:

• 1 is a view of the reflector from above (in the reference plane B),
• 2 shows a section along line 11-11 in FIG. 1,
• 3 shows a section along line 111-111 in FIG. 1,
• 4 shows a section along line IV-IV in FIG. 1,
• 5 shows a section through the one lateral mirror zone 2 along line VV in FIG. 1, and
• 6 shows a section through the other lateral mirror zone 3 along line VI-VI in FIG. 1.

The hood-shaped reflector consists of two mirror-image identical parts, which are arranged symmetrically to the main plane H and meet there in a limit curve KO (see FIG. 4); Therefore, only the right half of the two halves is described in more detail below: This consists of three bowl-shaped mirror zones 1, 2 and 3, each of which is the surface of rotation of a generatrix E with a radius of rotation r in the reference plane B about an axis of rotation M perpendicular to this reference plane .

The generator E1 of the central mirror zone 1 can be seen from the section in FIG. 3: It is a parabola in the lower third with a focal length of 0.524 based on the maximum diameter D of the reflector and a main axis angle β1 relative to the reference plane B of 25 °. The associated radius of rotation r1 is related to the axis of rotation M1 with the coordinates x1 and y1, which are calculated from the zero point 0 of a coordinate system. This coordinate system lies in the reference plane B, which is also the light exit plane; its zero point is determined by the intersection between the main plane H and a transverse plane Q running perpendicular thereto, which is also the longitudinal axis of the lamp L assigned to the reflector, which is a high-pressure mercury vapor lamp with a clogged bulb and the maximum diameter d. From Fig. 2 it can also be seen that this lamp is immersed in the reflector to such an extent that the center of the burner b lies in the reference plane B.

From FIG. 1 it is evident that not only lateral mirror zones 2 and 3 but also central mirror zone 1 are asymmetrical with respect to transverse plane Q; It is particularly important that the Y coordinate Y1 of the axis of rotation M1 is negative.

The lateral mirror zone 2 has a generating line E2 shown in FIG. 5, which has a parabola in the lower third with the focal length 0.524 related to the maximum diameter D of the reflector and a main axis angle β2 of 12.5 °, with respect to the reference plane B; the associated radius of rotation r2 and the axis of rotation M2 with the associated coordinates are indicated in FIG. 1. The cutting plane S2 is also entered there between this lateral mirror zone and the central mirror zone 1; it has an angle of attack a2 against the X axis of 36 °. The corresponding angle of incidence a3 of the sectional plane S3 between the central mirror zone 1 and the lateral mirror zone 3 with the larger rotation radius r3 is, however, negative and has a value of 45 °. In the sectional planes S2 and S3, the surfaces of rotation of the three mirror zones each meet in a common limit curve K2 and K3, the course of which can be seen in FIGS. 2 and 3 - albeit distorted by the projection.

The lateral mirror zone 3 has a generating line E3 shown in FIG. 6, which in the lower third is a parabola with the focal length based on the maximum diameter D of the reflector 0.755 mm and a main axis angle β3 of 2 °, based on the reference plane B; the associated radius of rotation r3 and the axis of rotation M3 with the associated coordinates are indicated in FIG. 1.

The values given in the claims apply to the length dimensions, the maximum diameter D of the refracting gate shown in FIG. 1 in the reference plane B having a value of 220 mm and being assigned to an 80 HQL lamp with a maximum diameter d of 70 mm .

The isolux curve that can be achieved in this case is shown schematically in FIG. 1 and designated J.

Claims (10)

1. 

   where D, the maximal diameter of the reflector in the reference plane (B), lies below 300 mm, and preferably has a value of 220 mm ±5%.
2. 2. A reflector as claimed in Claim 1, characterised in that the maximal vertex (h) above the reference plane (B), related to the maximal diameter (D) of the reflector in the reference plane (B), amounts to 0.54 ±10%.
3. 3. A reflector as claimed in Claim 1 or 2, characterised by a central reflecting zone (1) having the following values

   

   with a tolerance of +10%.
4. 4. A reflector as claimed in Claim 3, characterised in that the setting angle (a2) between the transverse plane (Q) and the intersection plane (S2) between the central reflecting zone (1) and the lateral reflecting zone (2) with the smaller rotational radius (r2) amounts to 36°±10%, and the setting angle (a) of the intersection plane (S3) between the central reflecting zone (1) and the lateral reflecting zone (3) with the larger rotational radius (r3) amounts to 45°±10%.
5. 5. A reflector as claimed in Claim 4, characterised in that in the third adjacent to the reference plane (B) the generatrix (E1) of the central reflecting zone is a parabola which has a focal length of 0.524 relative to the maximal diameter of the reflector and whose main axis together with the reference plane (B) forms a main axis angle (p1) of 25°.
6. 6. A reflector as claimed in Claim 4, characterised in that in the third adjacent to the reference plane (B), the generatrix (E2) of the lateral reflecting zone (2) with the smaller rotational radius (r2) is a parabola which has a focal length of 0.524 relative to the maximal diameter of the reflector and which has a main axis angle (p2) relative to the reference plane (B) of 12.5°.
7. 7. A reflector as claimed in Claim 4, characterised in that in the third adjacent to the reference plane (B) the generatrix (E3) of the lateral reflecting zone (3) is a parabola which has a focal length of 0.755 relative to the maximal diameter of the reflector and which has a main axis angle (ß3) relative to the reference plane (B) of 2°.
8. 8. A reflector as claimed in one of Claims 1 to 7, characterised in that the reference plane (B) simultaneously constitutes the light outlet plane which is determined by the edge of the reflector.
9. 9. An exterior lamp having a reflector as claimed in Claim 8, characterised by a lamp with ellipsoid bulbs and a maximal diameter (d) of between 55 and 75 mm.
10. 10. An exterior lamp as claimed in Claim 9, characterised in that half of the burner of the lamp lies in the reflector above the light outlet plane.

Images