US 1987019 A
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Description (OCR text may contain errors)
Jan. 8, 1935. H. L. LOGAN 1,987,019
I DENTAL LIGHTING SYSTEM v Filed Nov. 10, 1932 2 Sheen's-Sheet 1 IN V EN TOR.
, Henry L. Logan.
Jan. 8, 1935.
H. LOGAN v DENTAL LIGHTING SYSTEM Filed Nov.. 10, 1932 2 Sheets-Sheet 2 INVENTOR. Henry L. Logan.
A TTORNEYI Patented, Jan. 8, 1935 LIGHTING SYSTEM Henry L. Logan, New Rochelle, N. Y., asaignor to Holophane Company, Inc., New York, N. Y., a corporation of Delaware Application November 10, 1932, Serial No. 641,969
3 Claims. (Cl. 240-1) than those in common use.
The use of a fixed system of fighting for dental work has heretofore been considered impossible as a general proposition. Owing to the variation in height of dentists, the height" of the working plane above the fioor has to be varied, and, owing to the variation in height of the patient, there is a considerable range in the positions of the mouth, both as to its elevation above the floor and its position relative to the center or support of the dental chair. It is also desirable to swing the chair to some extent about this pivot. The net result of these conditions is that the mouth may be placed in an operating region which varies about one foot in height and has a horizontal dimension of a foot or more.
The lighting of the mouth during dental operations requires a high intensity of illumination with the light directed onto the surfaces on which the dentist is working, so that he can carry out the operations with adequate lighting, all of which must be received through the comparatively small opening of the mouth. The dentist .must be close to the patient and the operations must be carried out in various places in the mouth by instruments which the dentist holds in his hand, so that avoiding the creation of shadows in the mouth cavity is, important. These conditions have made it the almost universal practice for the dentist to employ movable light sources comparatively close to the patient. Such movable lighting apparatus clutters up the space about the patient and dental chair and requires adjustment by the dentist each time he or the patient moves. Such adjustments take the attention of the dentist away from the more important work in hand, are unsanitary, and annoying to th patient.
The present invention contemplates a lighting system for dental use which consists essentially of a plurality of simultaneously operated light sources placed in fixed positions. They are far above the operating chair so as not to interfere with the movements of the dentist and require no attention by the dentist. They are constructed to provide'very intense beams of light projected toward the center of the region occupied by the mouth cavity. While-the crossing of the beams is at this center, there is a region of considerable depth and width in horizontal directions which these fixed light sources illuminate to a very high intensity, of the order of 250 foot candles. This is obtained from three such sources with proper lenses and reflectors for projecting the light toward this theoretical center. The lights are so located as to provide not only horizontal illumination of the mouth cavity, but also a crossing of the light rays inside the mouth cavity for the illumination of vertical surfaces and to bring about diffusion to illuminateback surfaces. This arrangement also minimizes the casting of objectionable shadows by the dentist or the tools which he uses.
The preferred location for these light sources is in or near the ceiling of the room, but where'the room has too high a ceiling, the light sources can be supported on a chandelier-like structure at the desired elevation above the operating plane. Once this chandelier is installed, it requires no adjustment so long as the operating center is retained.
In order that the patient will not be unnecessarily annoyed by the lighting, the system is also designed so that the light sources are not within the normal field of vision of the patient when in the operating position.
Other and further objects and advantages of the invention will be apparent as the description proceeds.
The accompanying drawings show, for purposes of illustrating the present invention several'oi the many embodiments in which the invention may take form, it being understood that the drawings are illustrative of the invention rather than limiting the same. In these drawings:
Fig. 1 is a diagrammatic view illustrating an angular layout for the lighting units of the system in connection with an operating chair;
Fig. 2 shows a triple spot lighting system viewed from the rear of the operating chair with the three beams of light directed toward the oper-- ating point on the dentist's chair.
Fig. 3 is a cross-section o1 one of the lens units used for this system;
Fig. 4 shows a recessed lighting system with a number of dental chairs and triple spot directed toward each operating point but with lenses grouped together mechanically wherever possible;
Fig. 5 is an adjustable triple spot lighting unit; and.
Fig. 6 is another form of adjustable triple spot unit. j
Fig. 1 shows the head rest of a dental chair at 10. It is tilted at the usual angle topermit the dentist to work in the mouth (M). The line ,11 is projected vertically upward from the mean center of the unit 12, indicate a horizontal plane through the lighting unit 12, the line 13- 13 ex tending from the rear oi..the chair toward the front of the while the line 14--14 is at right angles to the line 1313.
Two other "lighting units are indicated at 15 and 16. The preferred spacing. of the lighting units 15 and 16 is at theapi'ces'oi an equilateral triangle, the line between the units '15 and 16 being parallel with the line 14--14 thereby locating these units on opposite sides of the patients mouth. The units 15 and 16 may be alike and are designed to project slanting light beams whose axes are indicated at 1'1 and 18. These slanting axes intersect the vertical beam axis 11 at a predetermined point which is at the centerof the region in which operating work is performed.
The line 19 indicates the normal line of vision iromtheheadrest. Astheheadrestisusually tilted from 30 to 45, this line 01' normal vision varies from 60? to 45 to the vertical. It has been found by experiment that the units 15 and- .16 should be placed at such a distance from the unit 12 that the beam axes 17 and 18 are at angles of approximately 35 with the vertical asindicatedinthedrawings. Thelineotvision isthentrom20to30 iromtheaxes otthe beams. With such an arrangement, the light comes at an angle suiiiciently near the vertical tobeiree iromannoyingglare,exceptwhenthe patient looks up to see the lighting units, and yet aflords a satisfactory amount of vertical illumination inside the mouth. It will thus be seenthatthere-arethreebeamsotlight,one vertical mm unit 12, the other two being oblique atangles at35 tothevertical and atanglesot about 33 to one another, all directed into the oral cavity. It will, therefore, be apparent that the light from these three sources in the 5 oral'cavity' and is capable of illuminating vertical and horizontal surfaces and of producing excellent diflusion around the'mouth for illuminating suriaces which cannot be directly reached.
This beam arrangement is one in' which the dentist is not annoyed by shadows cast into the mouth by his body or theinstruments he is using. InFig.2the118htingunit lfiisplaceddirectly over the patients mouth in the dentist chair.
The additional units 15and 16 are placed respectively on each side oi' the central unit and .iorward. Unit 12 has a lens unit directing a beam straight downward. Units 15 and 16 direct slanting beams atan' angle 'to converge at the same point, viz., the patients mouth M. The lens units 12, 15, audio are'placed on a ceiling, the height of which is indicated atline C. It the ceiling is higher, as shownby the dotted line C,
' the units are placed farther apart,- but in the same angular relation to one another and so that the beams still converge at exactly the same point. Unit 12 is raised to the position 12'. Unit 15 is carried back along the line 17 to'the position 15'. Unit 16 is carried back along the line 13 to the position 10. By moving these units backalongtheaxesl'iandlsoitheslanting' beams, they are placed at'a new location on'the higherceilingsuchthatthebeamsarestilldirected exactly to the same point as-baioreQIt' directthelightattheproperangledownward. 5
However, a part 01 this angular direction downward is obtained by oii'setting the light center 21 somewhattromthe axisnoithelensmpThis permits a somewhat, lesser degree of tip to the lens than would be n Hall of the tip of the light beam were obtained by tipping the lens. When beams or other obstructions on the ceiling interfere with the location 01' a unit at exactly the proper point, the unit may be moved to one side or the other. Then the proper angle oi beammaybeobtainedbyachangeinthepofltion of the light center 21 to one side or the other 01' the position shown in Fig. 3'. In the unit shown in Fig. 3- efliciency is increased by the use of a spherical reflector 23 placed above the light source. Diflusing glass sides of opal or V otherglassmaybieusedintheseunitsasindi cated at 24. This gives. a spread or diii'us'ion to the transmitted light as shown at 25 and helps to provide general illumination in the room with asoitpleasingeflect.
Fig. 4 indicates the application oi the system to an installation having a plurality or dental chairs. Suchaninstallationmightbeplacedin a dental college. Wherever the proper location 'otlensesinsuchasystembringathelensestogether,theyaregroupedtogetherinthesame boxtoobtaintheadvantasesoiabankconstruction of the boxes ior thelamps.
Fig. 5 illustrates, "a triple spot unit as suspended from the ceiling by a single support. A triangular box carriesthree lenses 31, 32, and 33. each with its individual lamp. The lamps are so set with'reierence to the lens tool as to produce concentration at :the operating 40 point. Inthisunit,thetopcoverottheboxis ward the operating'p'oint. The distanoeoi the 1 boxes 36, 37.and 3i! from the adjustment may also be introduced if desired.
It may sometimes be necessary to have the lighting unit 12 slightly ofiset, so as not to be directly over the center of the operating region. Slight inclination of the beam of this unit corrects for the displacement of the unit.
The lenses and reflectors are designed to produce beams of very small divergence so that the cross section of the beam of controlled light is but little larger than the lens. A large amount of scattered and uncontrolled light is emitted from each unit so that a high level of general illumination is available without additional lighting apparatus.
It is obvious that the invention may. be embodied in many forms and constructions, and I wish it to be understood that the particular forms shown are but a few of the many forms.
for providing intense illumination vertically, and two lighting units each having light concentrating lenses. the latter light units being spaced from one another and equally spaced from the first lighting unit and arranged to'project intense beams of light toward the mouth cavity, the three units having fixed spacial relationship and singularity, said lighting units being a predetermined distance above the dental chair, the light beams crossing in the region of the mouth cavity toprovide illumination of vertical surfaces such as teeth and gums, the latter mentioned lighting units being placed sufliciently close to the first unitsoastobebehindthenormaldirectionof sight of the patient to reduce glare from the surface of, the lenses in the patients eyes.
2. Lighting apparatus as set forth in claim 1,
characterized in that the axes of the oblique beams are at substantially with the axis of the vertical beam.
3. Lighting apparatus as set forth in claim 1, characterized in that the lighting units are at the apices of an equilateral triangle, the slanting beams being projected at equal angles to the vertical.
HENRY L. LOGAN.