Medical headlight

Feb. 27, 1968 w. c. moore etal 3,371,202

MEDICAL HEADLIGHT

Filed July 21, 1966 2 Sheets-Sheet 1

<img file="US3371202A_D0001.tif" />

Feb. 27, 1968 w. _c. moore etal 3,371,202

MEDICAL HEADLIGHT

Filed July 21, 1966 2 Sheets-Sheet 2

<img file="US3371202A_D0002.tif" />

United States Patent Office ³·³⁷¹’²®² ___ Patented Feb. 27, 1968

3,371,202

MEDICAL HEADLIGHT

William C. Moore, Skaneateles, and John D. Connors, Auburn, N.Y., assignors to Wech Allyn, Inc., Skaneateles Falls, N.Y., a corporation of New York ⁵

Filed July 21, 1966, Ser. No. 571,377

Claims. (CI. 240—41.15)

This invention relates to a medical headlight and more particularly to a headlight providing a manually controllable high brilliance field of illumination of substantially uniform intensity and free of striae.

The principal object of the invention is to provide a headlight adapted to be worn on a headband and having a low-wattage and high intensity light source, a light re- 15 fleeting and projecting system for uniformly projecting forward the maximum amount of light, and manually operable iris diaphragm means for controlling the size of the illuminated field.

Another important object is to provide such a head- 20 light having a substantially uniformly illuminated field free of striae and areas of contrasting brilliance.

Still another object is to provide such a headlight which is light in weight and from which heat is dissipated rapidly, but which does not become painfully hot to the touch. 25

A further object is to provide such a headlight furnishing a highly illuminated field with a minimum of projected heat thereat.

Other objects and advantages will become apparent fiom the following description in conjunction with the 30 accompanying drawings, in which:

FIGURE 1 is an enlarged longitudinal sectional view of a headlight embodying the invention;

FIGURE 2 is a plan view thereof on a reduced scale;

FIGURES 3 and 4 are rear and front elevational views 35 thereof, respectively; and

FIGURES 5, 6, and 7 are sectional views on the lines ⁵—5, 6—6, and 7—7, respectively, of FIGURE 1.

In the drawings the headlight 10 comprises a base 11, an inner housing 12, an outer housing 13, a light source 40 14, and iris diaphragm assembly 15, and a condensing lens 16.

The annular base 11 is of an electrically nonconductive material and is provided with a threaded metal plug 17 at its center to which is secured a metal stud 18 which has a plastic covering 19 having a ball-shaped configuration adapted to be adjustably secured in a socket attached to a headband, not shown. Base 11 is provided with a pair of terminal wire screws 20 threaded into the forward side thereof. A pair of curved slots 21 in the base, best seen in FIGURE 3, between the screws, provide openings through which lead wires 22 pass from a transformer or other source of electricity, the wires having their ends secured by the screws 20 to metal contact strips 23 and 23α, respectively, as best seen in FIGURE 1.

The inner housing 12 is of aluminum and is made in two parts, a tubular rear section 12α, and a hollow forward section 126. Both sections are provided with a plurality of radially projecting annular heat-dissipating fins 25 therearound and the rear section has a central lamp-receiving socket 26. The socket is provided with three bayonet type slots 27, best seen in FIGURE 5, for reception of lugs 28 on the lamp 14.

The rear section 12α is provided with an internally threaded annular flange 29 projecting into the central passage of the base 11 and with which plug 17 is threaded¹/ engaged. The annular flange 29 is diametrically slotted at 30 so that the contact strips, 23 and 23α can pass therethrough.

Base 11 is also provided with a forwardly projecting annular flange 31 engaged against an appropriate annular

SO shoulder 32 around the rear end of housing section 12α. Flange 31 is also diametrically slotted at 33 for the passage therethrough of contact strips 23 and 23α, a longitudinally extending slot 34 being provided in the lamp receiving passage 26 for the reception of the bent over end of strip 23α.

The forward end of the housing section 12α has an elliptical depression in which an elliptically curved reflector 35 is secured by swaging over the end of housing section 12α. Reflector 35 is a brass or other metal made diffusive by finely etching or sand blasting its reflecting surface before it is coated to make it reflective and it is shaped to reflect forward light from the source 14 as hereinafter further described.

Reflector 35 has a central passage therethrough conforming to the outline of passage 26 including the forward ends of the bayonet slots 27, so that base 37 of lamps 14 may be inserted rearwardly and removably secured in passage 26.

Lamp 14 is of the quartz-iodine type for maintaining the glass envelope 38 thereof free from tungsten deposits. The usual tungsten filament 39 is supported in the glass envelope 38 on a pair of terminal wires 40 which extend through the end of the narrowed neck of the envelope, one being soldered or welded to the metal base cup 37 and the other being similarly secured to the metal center lamp contact 41 as best seen in FIGURE 7. Lamp base 37 bears the lugs 28 and is filled with a ceramic material which secures the envelope, base, and center contact together in the usual manner.

The configuration of housing section 12α is such that filament 39 lies substantially in the plane of the forward end of reflector 35 and at one focal point of the elliptical reflector 35, and the configuration of the reflector is such that its other focal point is slightly rearward of the diaphragm 15 and on the housing axis.

The forward section 126 of the inner housing is provided with an annular flange 43 fitting closely around the forward end of the section 12α and the rearward end of section 126 is rounded to provide a rearwardly facing interior spherical surface 44 which is polished for reflecting divergent light back on to the elliptical reflector 35. The center of curvature of surface 44 is substantially at the center of the. filament 39 and on the axis of housing 12 so that light emitted from source 14 forward, but nonaxially, is reflected back to be again reflected forward from reflector 35.

Forward of the reflective surface 44. housing section 126 has a converging frusto-conical interior surface 45 which is also polished to collect diverging rays of light and reflect them substantially axially and forward. Another frusto-conical interior surface 46 forward of the reflective surface 45 diverges forwardly to a cylindrical portion 47 of the passage in which is secured the iris diaphragm assembly 15. Forward of the diaphragm the passage, walls at 48 diverge again to another cylindrical portion 49 in which is secured the lens 16.

The iris diaphragm assembly 15 comprises a cup shaped outer member 50 secured in the housing passage by setscrew 51. An annular inner member or plate 52 is rotatably secured within member 50 by a snap ring 53. Between plate 52 and the centrally apertured forward wall of member 50 are secured a plurality of leaf members 55 in fan-like manner, only one leaf being shown in FIGURE 1.

As best seen in FIGURE 6 the outer member 50 is provided with a plurality of holes 56 disposed in a circle around its central aperture and each hole 56 journals a stud or projection 57 from the forward face at one end of a leaf 55, only four leaves being shown. At the other end of each leaf a stud or projection 58 extends in the

3,371,202 other direction into one of a plurality of grooves or slots 59 in the forward face of the rotatable plate 52, as shown in the lower portion of FIGURE 6 where the outer member 50 is shown cut away.

Radially of the inner plate 52 a diaphragm operating lever 60 threaded into the plate projections through appropriate slots in the outer member 50, inner housing 12, and outer housing 13. When lever 60 is turned to the left, as viewed in FIGURE 6, it will be apparent that the size of the central aperture 61 will be constricted and, when turned to the right, will be enlarged.

At the forward end of housing 12 an annular shoulder 62 is provided against which the lens 16 is secured, the forward end of housing 12 being internally threaded and a lens retainer ring 63 threadedly secured therein against the forward face of the lens. Lens 16 is aspheric and designed to condense the light coming through the diaphragm aperture 61 forward of the lens upon the field to be illuminated.

The outer housing 13 is of a molded plastic material having poor heat conduction quality, such as polycarbonate plastic, and is provided with a plurality of circumferentially disposed ventilating slots 65, as best seen in FIGURE 2. At its rear end housing 13 is threadedly engaged with the base 11, as clearly shown in FIGURE 1, and at its forward end an internal annular shoulder 66 is provided. Three radially projecting and equiangularly disposed ears 67 extend from the forward end of the inner housing 12, as best seen in FIGURES 4 and 5, and rest against the shoulder 66.

Forward of the ears 67 a housing retaining ring 68 is threadedly engaged against the ears in the internally threaded forward end of the outer housing 13. The retaining ring 68 secures the forward end of housing 12 coaxially within housing 13, holds the portions 12α and 12/? of the inner housing together, and, together with plug 17, compresses portion 12« against the slotted annular flange 32 at the forward end of the base 11. Both retainers 63 and 68 and the plug 17 may be diametrically slotted, at 70, 71, and 72, respectively, for appropriate spanner type wrenches or tightening tools, as indicated in FIGURES 3 and 4.

A slip ring 75 encircles the outer housing and the shouldered outer end of the diaphragm operating lever 60 is engaged therewith. One or more pins or screws 76 projecting radially inward from the ring 75 are engaged in appropriate arcuate grooves around the outer housing for securing ring 75 on the housing.

In operation, the headlight 10 is worn on a headband, the ball 19 attached to base 11 being gripped in a socket on the headband, and the light may be directed manually in the desired direction. When the headlight is turned on, by a switch not shown, light is directed forward of lens 16 and the size of the spot or illuminated portion of the field is regulated by turning ring 75 as desired.

Since light from the reflective surface system is focused at a point on the housing axis short of the diaphragm 15, the light is centered or focused on the aperture 61, whatever its size and then condensed by lens 16 and projected to the area to be illuminated.

Using a 12-watt lamp 14, the intensity of the light at the center of the illuminated spot at a distance of 14 inches from lens 16 measures 500 foot-candles, the intensity of the light at portions of the spot away from the center falling off very gradually. At this distance the spot is about 6½ inches diameter when the aperture is enlarged to its maximum and the intensity is about 300 foot-candles near the perimeter. This is about five times the light output of ordinary headlamps of the prior art.

The continuously enclosed passage in the inner housing from source to lens in combination with the ellipticalspherical reflector system 35, 44 has been found to utilize about 25% more of the light from the source than conventional systems and the conical reflector 45 has been ⁴ .

found to add about 7% more to the light effectively utilized by the lens.

Controlling the size of the illuminated field or spot by the iris diaphragm, instead of by more conventional means 5 increasing or decreasing the distance between a lens and the source, has been found to completely eliminate contrasting bright and less bright areas in the spot because the image of the element 39 is never projected through the lens system on to the field. Moreover, principally because of the diffused surface on the elliptical reflector, uniformity of light over the area of the spot is increased and the annular lines or striae usually present with conventional headlights are also eliminated.

A 12-watt light source of the quartz-iodine type, be15 sides maintaining its brightness throughout the life of the lamp due to the washing away by the iodine of the usual tungsten deposits on the glass envelope, has been found to have a useful life of 80 hours or more of continuous use, as against 50 hours for the best of the more conven20 tional lamp systems. Moreover, the continuously enclosed passage in the inner housing 12 from light source to lens allows the low-wattage lamp 14 to heat up and remain at its optimum operating temperature. Instead of cooling the lamp, the fins 25 on the inner housing and the slots 65 25 in the outer housing provided for cooling the inner housing while allowing lamp 14 to remain at its optimum operating temperature.

Furthermore, the heat dispersion system including the finned metal inner housing and the plastic slotted outer 30 housing has been found ample for cooling the headlamp even though a high brightness lamp is used, and the outer housing does not become so warm to the touch of the wearer as to cause discomfort while adjusting the light.

As will be apparent to those familiar with the art, the 35 invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiment disclosed therefore is to be considered in all respects as illustrative, rather than restrictive, the scope of the invention being indicated by the ap40 pended claims.