Patent GB-435946-A (GB)
Title: Improvements in or relating to machines for the manufacture of corrugated reflectorsespecially for automobile headlights
IPC: B23Q35/10
Filed: 1934-07-12
Abstract: 435,946. Making corrugated lamp reflectors &c. SOC. POUR LA FABRICATION DES PROJECTEURS ELECTRIQUES MARCHAL, 14, Rue MÚhul, Pantin, Seine, France. July 12, 1934, No. 20517. Convention date, July 13, 1933. [Classes 83 (ii) and 83 (iii)] [See also Group XI] Lathes.-In a machine for making corrugated reflectors or dies for making such reflectors particularly for automobile headlights, a tool carrier guided by a cam is given a rotary movement combined with a variable linear movement parallel to the plane of the corrugations. In a known form of sectional reflector, Fig. 1, of generally paraboloidal form, a horizontal section shows points b, b<1>, b<2> representing the intersections of vertical parabolas with the plane of the paper a limited horizontal spread of a beam from a point source F is obtained as shown. As made by a machine according to the invention, the flattened reflector surfaces b b<1>, bl b2, &c. are replaced by curved corrugations, Fig. 3, which may be either convex towards the focus F or concave thereto. In this way a greater horizontal spread of the beam is obtained. The dies for stamping out such reflectors may be made by a machine wherein a fixed spindle 1, Fig. 4, carries a cam 2 of parabolic or other outline and supports a rotary plate 3 carrying a tool support 5 which is urged against the cam by a spring 8. The tool 6 is pivoted to its support at 6b. In operation. as the tool support rotates around the axis 1 the tool cuts a series of grooves in the work 11 which is displaced so that the tangent at the apex of the tool path always intersects the parabola formed by the intersection with the work of a horizontal axial plane. The work carrier 10 is mounted on a pair of compound slides 12, 13 and 14, 15, the member 17 carrying the upper compound slides being angularly adjustable around a pivot 18. The carrier 10 has a depending arm 10<a> resting on the machine bed and is angularly adjustable around a bolt 19 on the upper carriage. If the corrugations are sufficiently narrow to be made in a single revolution of the tool, the die 11 may have successive displacements equal to the width of the corrugations, the tool being adjusted around its pivot to maintain it at right angles to the die surface. For making wider corrugations, Fig. 8, having a tangent OP at the apex O of the corrugation which is inclined at an angle a with the machine axis, the member 17 is angularly adjusted to a position x x<1> inclined at an angle alpha with the machine axis. The work carrier 10 is then adjusted around the bolt 19 until it is again parallel to the machine axis. In this way the displacements produced by movements of the carriages 14, 15 are in the directions x x<1>, y y<1> respectively. A cam 20 of similar form to the required corrugation may be secured to the carriage 14 and engaged by a roller 21 on the carriage 15 so that any movement of the carriage 14 in the direction x x<1> will effect a corresponding movement of the carriage 15 in the direction y y<1>. In the machine shown, the carriage 14 carries a plate 22 fitted with a lever 24 whose small arm carries a roller 25 spring-pressed against a stationary stop 28 on the member 17. The long lever arm carries a cam 29 of similar outline to the corrugations to be cut. Another lever 30 pivoted at 31 to the plate 22 has at one end a roller 32 engaging the cam 29 and at the other end a stop 33 engaging a finger 34 on the carriage 15, a spring 35 pressing the parts 33, 34 together. As the carriage 14 is traversed by means not shown, the lever 24 is caused to swing and the cam 29 acts through lever 30 to impart corresponding displacement to the carriage 15. By this arrangement a cam 29 of larger size than the corrugations may be employed. In some cases the reflector or die, Fig. 9, may have curved corrugations only over the part c around the apex thereof. In this case a cam 2 of circular form may be employed. The other part of the work may be either smooth or provided with corrugations of the form shown in Fig. 9. The Specification as open to inspection under Sect. 91 describes also a modification wherein the cam 2 is replaced by a cam 38 having paraboloidal or other suitable sections in planes perpendicular to that of Fig. 4. The movement of the work between successive corrugations could then be dispensed with, the corresponding movement being given to the tool by arranging the roller 7 to move along different portions of the cam surface 38. In this form the different corrugations may be bounded by curves of different shapes. The The same result may be obtained by the employment of a number of different cams 2 for cutting different parts of the die. This subject-matter does not appear in the Specification as accepted.