US1668706A - Manufacture of headlights - Google Patents

Description

May 8, 1928.

w. H. woon MANUFAC'LURE OF HEADLIGHTS 2 Sheets-Sheet 1 WILLIAM H. WOOD Filed Aug. 17, 1923 I l I I l a l l I INVE NTOK WW ATTORNEYS on w W. H. WOOD MANUFACTURE OF HBADLIGHTS May 8, 1928.

Filed Aug. 17. 1923 2 Sheets-Sheet 9 fi 5j6 5 97 WlLLlAM H. W000 I INVENTOR.

v ATTORNEYS Patented May 8, 1928.

UNITED STATES WILLIAM 1:. W001), or SOUTH EUCLID,OH10.

munacronn or nnanmenrs.

Application filed August 17, 1928. Serial N0. 657,996.

This invention relates to vehicle headlightsand has for its object the provision of a new and improved punch and die whereby a onepiece sheet metal reflector canbe simply and easily made which shall produce a legally acceptable and practically satisfactory distribution of light without the use of lenses, prisms, shades, dimmers or other expensive, fragile, or light killing devices. Other objects of the invention relate to the production of such a punch and die each from a single piece of metal; the provision of a punch of such construction that it can readily be dressed or re-shaped; the provision of a device of this character which can be very quickly and cheaply produced; the provision of an improved headlight reflector, while further objects and advantages of the invention will become apparent as the description proceeds.

In my former application filed Jan. 24, 1923, Serial No. 614,694 I described a certain mathematical surface for use in the construction of headlight reflectors for producing a light which is not only legally satisfactory, but also to a considerable extent in:

dependentof minor variations in focal distance. The present invention contemplates the use of these curves, or other curves similarly found, but refers specifically to the manner of impressing these curves upon the metal block whereby the tool itself is produced. In the drawings accompanying and forming a part of this application wherein I haveshown in detail one mode of producing my improved tool; Fig. 1 is a diagrammatic view showing the mode of generating my improved curve as employed for the top portion of my reflector; Fig. 2 shows the mode ofgeuerating my improved curve as employed for the lower part of my reflector; Fig. 3 is a diagrammatic View showing the preferredmode of assembling these curves together and disposing them with reference to the horizontal, this diagram conforming substantially to the central vertical sectionof my preferred reflector; Fig. 4 illustrates the first step in the preparation of my im-' punch shown in Fig. 9; Fig. 11 shows the same punch after having had the next cut taken off its upper portion; Fig. 12 is a front view of the punch shown in Fig. 11; also illustrating the nature of the next succeedingstep; Fig. 13 is a side elevation of the 'con'ipleted punch; Fig. 14 is a vertical central section of a reflectormade thereon;

Fig. 15, is a front elevation of the reflector shown in Fig. 14; Fig. 15 is a face View of the die or ring member. with which the punch co-operates; and Fig. 17 is a sectional View of the ring shown in Fig. 16.

My improved curve consists in effect of a plurality of parabolas merging one into the other, each portion corresponding to a different focal point. The shape of the curve for the top half of the reflector is materially different from that of the lower part and is developed as follows: I draw the line 1--1 of Fig. l torepresent the horizontal axis and above it I locate the point S say onefourth inch there-from, this distance corresponding to the intended elevation ofthe light source above the reflector axis. It will be understood that this displacement may be either less or greater than the amount I have suggested, and will also depend upon the focal depth of the curve. difficulty will be experienced in merging together the different surfaces inasmuch as theyywill be severely warped; if made too small, the desired lightcontrol will not be obtained. The present drawings are exaggerated in all respects in; order to'show the theory of operation within the small scale permitted.

Through the point S I draw a vertical line two inches long ending at the axis at This line corresponds to the parameter of a parabola andits upper end 3 is a point of the curve at which its inclination to the axis 1-1 is substantially 45. Also at a point in the rear of the line 2-3 I draw a parallel line. I)--I) at the same distance from the point 3 as 3 is distant from This line corresponds to the directrix of a parabola, and the procedure thus far conforms exactly to that which would be followed if a parabola "were to be drawn about the point 2, with a focal distance of one inch. Of course I do not limit myself to this size.

However, if the point S be considered as a light source, then its virtual position along the axis 1 will depend upon the angularity with which the rays strike that axis. For

If made too great,

example I now draw an inclinedlilre through the point S so as to intersect both the axis 11 and the probable curve, say the line e intersecting the axis at 4. I then draw a perpendicular E,E the same distance behind the line D,-D that 4 lies in front of 2 and on theline e I locate the point 5 which is equidistant from the line E-E and the intersection 4. In, other words the point 5 constitutes a pointon a-parabola whose true focus is '4 and directrix is E -E. I

I then draw anotl-ier inclined line/g through the-point S "intersecting the axis at 6, andalso'drawa corresponding directrix (,l-(ias far behind'DD as the point (ilies in front of the point 2. On this line I then ...1'i11(l the point 7 which equidistant from the paint 6 and from the line ,GG,, the point being upon aparabola whose focus is (i and whose directrix is G G.- I repeat the same performance for a sufficient .number of other lines to locate other-points '8, 9, etcand thus plat an accurate curve between the parameter and-the ,vertex.

I then draw an inclined line through the point S' intersecting the ax1s at 12*between the parameter and the vertex and vto accompany itI draw a perpendicular J-J as far in front of the line D-D as 12 is behind 2,.

after which I find the point 13 on this line which is equidistant from the point 12 and the line J-J,- this point-being located on a parabola whose focus is 12 andwhose directrix is JJ This is repeated forthe lines 7c and I--K etc. and giving points 14, 15 andas many other times as desired after which a curve Y is drawn connecting the points 3, 5, 7, 9, 11,13, 15.

To plat the line below the axis I draw a second straight line 2020 as in Fig. 2 and place a t one-fourth inch above 1t (or whatever distance I prev ously employed), a point S from which I- drop a perpendicular 7? intersecting the axis at 21; and on this line at about two and one-fourth mches (more or less, but preferably a little more than the distance 23 for a reason to be explained hereafter) below the line I locate the point 22 which is a point on the curve. Also I drop the perpendicular PP so located that the point 22 shall be equidistant from-21 and from PP.

I then draw an inclined line 1 through the point S" intersecting the axis 20 at 23 behind the point 21and I also draw a second perpendicular Q-Q the same distance in front of YPI as 23 is behind 21. line 1 I then locate thepoint 24 equidistant from the point 23 and from the line After repeating this with other lines 1, it,

etc. I find the points 26, 28 etc. sufficient in number to define an accurate curve. I draw other lines as u, and o intersecting the axis in front of the point 21v and for each I draw a corresponding perpendicular as On the i UU, V-V an equal distance behind the line PP thus finding the oints 30, 32, etc.

in the same fashion. I t en connect the points 22, 24, 26, 28, '30, 32 produclng the curve Z.

It can be dei'i'ionstrated that each of the curves plotted as hereinbefore described concentral vertical section made by assembling these curves as shown in Fig. 3, the line 15-91, being superposed upon the line 20-20 with the point S located slightly behind the point k If the distance 21, 22 was properly chosen relative to the distance 2-tl,"the

vertices of the two curves will match properly with the desired longitudinal separation of these points which is preferably rather small say inch (it will be understood that the present patent drawings are entirely out of proportion in order to produce slifli-, cient separation ofthe different points and lines for ready reference). If a light source A be located at any point between S and S,

.all rays fallingon Y will be reflected forwardly and downwardly as shown at C. Indeed this downward deflection is sogreat as torender it desirable to tip the reflector upwardly as regards the horizontal line I'I"II. The dotted line F in Fig. 3 indicates a true parabola drawn about the axis 20 for purposes of comparison. 5 I i I will now describe the mode whereby I apply my improved curvesto the Inetaltool whereby this reflector is made. I first take a suitable block of metal shown bythe dotted outline40 in Fig. 4 and on the one side I turn a cylindrical boss 41 while the opposite portionof theblock is formed by a surface of revolution of the portion Z of the curve already described, the axis 2020being coaxial with the boss 41 and with the axis of revolution. This produces a mushroom-shaped metal block which. is now shifted bodily laterally to a new' axis of revolution 42-42 parallel to but spaced from the axis 20 -20. and the block is again machined to conform to the surface of revolution of the same curve about the axis 42 with a radius equal to slightly less than the sum of the displacement 42 plus the, previous radius. Vhile in this position I cut into the block at one side-throughout the are indicated approximately at 4343 in Fig. 6, thereby slightly flattening the block on one side and taking off a comparatively thin layer indicatedat the bottom Of Figs. 5 and 6. This accomplished I shift the block still further till -extend over in the same direction and again turn itabout the axis 45, parallel to the first axis but displaced yet further in the same direc tion, and cause the same to conform throughout a yet narrower area to the surface of revolution of the same curve about a radius similarly increased. In this way I remove a yet narrower region represented by the are 46-46 in Fig. 8. A still greater number of settings can be made if desired, but is unnecessary. Indeed I have had excellent results with only a single oii'set cutting. 3 l

I; now offset the block in the opposite direction to an axis 418 -l8 and machine it to conform to the surface of revolution of the curve Y about this new axis, the radius of rotation being increased by the distance be-- tween 20 and 4-8. If this displacement is properly chosen, the block will be surfaced over only a part of its circun'iference, the bottom portion of the block swinging inside this new surface of revolution. In the embodiment here illustrated the curve Y is much smaller than the curve Z owing to the comparatively great vertical displacement of the points S, S, and for this reason the cut extends more than a half circnn'iference, from 49- 44). In actual practice with the measurements here indicated the cut will not even a semi-cireumference. Either condition is equally satisfactory since the side wings hereafter desribed will lill the gap if such exists. Thereupon the block is again shifted to an axis 50 yet further displaced and is again machined to the same surface of revolution about a similarly in.- creased radius, only a comparatively narrow strip being out along the extreme top of the punch as indicated bythe arc 51-51 in Fig. 12.

The block is now shifted to a new and very eccentric axis 52, located somewhat be low the axis 20 and very materially to one side, and a side wing turned throughout the are 53 53 extending from the largest portion of the die to a point substantially opposite the parameter. This wing will appear slightly flattened and somewhat wedgeshaped as indicatedat X in Fig. 13; after which the block is again shifted to the axis 5% symmetrically located as regards the axis 59 and corresponding to the are 55 All these various sections, if the work has been carefully done as herein directed, will merge together with very little unevenness. it will be necessary to smooth down the meeting edges with a fine file but the only care necessary in this regard is not to dress the same too much, merely to remove rough-- ness and produce a smooth blending. The block is now mounted in a base plate 56 shown in Fig. 13 having a shank 57 adapted to fit the socket of the punch press plunger, the face and back of this base plate being inclined the amount by which the axis of the lamp is todi'verge from horizontal. The punch is ren'iovably secured to this plate so as to permit redressing in case of need.

Owing to this inclination the punch will strike the die at a slightly different angle from that originally exhibited namely along the line (5()-60. This die, therefore, consists merely of a steel ring 61 having .its inner face (52 shaped to conform to the section of the punch along this line, Common boiler plate is amply smlicient for this ring. The absence of any reentrant angles or deprcssions in the surface of the punch dispenses with the need for a receiving memher which shall .in other words a bottoming die. The reflector produced by this tool is illustrated in Figs. 14 and 15, and is made by a single stroke of the tool, the edges of the plate being meanwhile gripped against the ring 61 in the manor well known to all those skilled in the art of metal drawing; A por tion of this metal left as at 65 to form a stiffening rim or flange whose exterior is trimmed to circular shape, While the heel of the reflector is provided with an aperture V for the reception of the lamp socket, thesame being located sufficiently above the axis 2U-20 to bring the light source. the desired distance therefrom.

It will be understood that I do not limit myself to any one relation of distances or ratio between the upper and lower curves or displacement of the foci of said curves or in anywise except as herein claimed. Indeed it will be noted that if these directions be accurately followed the axes 1--1 and 202O will"overlap each other by a short distance. This is no practical detriinei'it but can be avoided by producing the ori al blank about an axis located son'n-iwhere between the lines 20-90 and 42 in Fig. The effect of this to cause the line 2%)20 to describe a. cylinder of revolution whose diai'neter is equal to the sum of the cuts which are to be taken off the top and bottom of the blank. If this be done at the start, then the final punch will exhibit the exit section shown in Fig. 8; if it be not done the device will be narrowed by this amount, although if properly designed the lightwill still be acceptable. This is only a working allowance such as any carpenter must provide every time he saws a board, but my invention is not restricted to such nicetics although the accuracy of the result is improved thereby. Also I have described a. device made by swinging the blank about mimei'ous axes 20. 42. 48, 5U, :32. Fiat. all of which are parallel to each other which is extremely convenient in practice since it permits the tool to he made on a common lathe merely by shifting the block about on the face plate, but I do not limit myself to this coaforin closclv therewith,

parallel arrangement. Also I do not limit myself to the use of all. the curves and set tings shown, as in some instances it may be feasible to dispense with the side wings or other elements; and conversely I may use additional curves and additional settings.

Certain of the reflectors described herein, and illustrated in the drawings are claimed in my copendii'ig application filed kieptenr ber 22, 1927, Serial No. 221,153, filed as a continuation of my application No. 6l l,694l, filed January 24L, 1923. l

Having thus described my invention What I claim is:

.1. A one-piece metal punch for reflectors having its surface convex at all points and having its different regions formed as surfaces of revolution about a plurality of different longitudinal axes.

2. A one-piece metal punch for reflectors having its surface convex at all points and having its different regions formed as sur- 7 faces of revolution about a plurality of longitudinal axes, all of which are located in a single plane.

3; A one-piece metal .punch for reflectors opposed regions of which consist of surfaces of revolution about different longitudi nalaxes of curves which are parabolic as regards a focal point displaced from all such axes.

4. A one-piece metal punch for reflectors, having the portions upon opposite sides of its principal axis formed as surfaces of revolution of dissimilar curves about eccentric axes. i

5. A metal punch for reflectors having a portion corresponding to a surface defined by the rotation of a segment of a parabola about an axis inclined to the parabolic axis.

6. A metal punch for reflectors having a portion defined as the surface of revolution of a segment of a parabola about an axis which is oblique to the parabolic axis and displaced from the focal point.

7. A bilaterally symmetrical one-piece metal punch for reflectors Whose intermediate regions are'surfaces of revolutions of hyperbolas about different longitudinal axes.

8. A bilaterally symmetrical metal punch for reflectors having its cross section defined by a pair of opposed semiovals of unequal curvature, the ends of said semiovals being joined, by arcs whose centers lie at the same side of the longitudinal axis of the oval and upon opposite sides of the transverse axis.

9. A bilaterally symmetrical metal punch for reflectors whose-lateral regions are surface of revolution about a pair of spaced axes and whose intermediate regions are surfaces of revolution about a plurality of parallel axes all of which are contained 1n a plane perpendicular to the plane which contains the first two axes.

10. A bilaterally symmetrical one-piece.

axesall of which are contained in a single.

plane and having its lateral portions connected by surfaces of revolution about axes displaced upon. opposite sides of such plane; 11. A one-piece metal punch for automobile headlight reflectors having external portions formed as surfaces of revolution about axes which are oblique to the axis of the punch.

' 12. A one-piece metal punchfor automo bile reflectors, the punch axis oblique to the axis of the curve which defines the reflector surface.

In testimony whereof, l hereun'to afiix my signature. I

l/VILLIAM H. WOOD.

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