US 3629568 A
Description (OCR text may contain errors)
States Patent MacArthur,jr.
Primary Examiner- Louis .I. Capozi Attorney-Pastoriza and Kelly ABSTRACT: A mounting screw for an instrument includes a shank portion having a cutout on one side. A light bulb is cradled in the cutout to emit light laterally from one side relative to the axis of the screw. Conductive slip rings circumferentially extend over the opposite side of the shank portion in axially insulated spaced relationship such that when the mounting screw is inserted in a receiving screw hole in the instrument casing adjacent to the instrument dial, the dial is internally lighted, the screw serving the dual function of mounting the instrument and providing support for the internal 7 lighting.
PATENIEUUECZI an 3.629.568
ARNOLD LOYD HAN ES BY IG.5 FIG 4 F M2374? A770 NEVS SCREW AND LIGHT COMBINATION FOR INSTRUMENT LIGHTING This invention relates generally to instrument lighting and more particularly to a novel screw which might be used for mounting the instrument to a panel or securing portions of the instrument itself together and simultaneously serve to support a light source for illuminating the dial of the instrument.
BACKGROUND OF THE INVENTION It is becoming increasingly desirable to illuminate instrument dials internally. Particularly is such the case in aircraft instruments wherein external lighting sources in the cockpit can be annoying to the pilot of the aircraft particularly because of reflections from various other components in the cockpit.
It has been the practice, accordingly, to utilize miniature light bulbs internally within the instrument in conjunction with a light wedge or light-conducting material which affords a relatively uniform illumination of the instrument dial by a bulb located to one side within the instrument. The principal difficulty with such designs arises from the necessity of changing light bulbs when a bulb burns out. In most instances, changing of the bulb requires the removal of the entire instrument from the panel. The instrument must then be taken apart for the bulb change.
One particular design is such that the bulb can be changed from the front but in this instance all of the mounting screws must be removed and the bulb change then effected.
BRIEF DESCRIPTION OF THE PRESENT INVENTION The present invention provides a novel internal lighting means for instruments which overcomes the difficulties encountered heretofore in changing the internal lighting bulbs.
More particularly, in accord with the invention the internal lighting bulb is incorporated in one or more of the mounting screws for the instrument. By this arrangement, to change a bulb it is only necessary to take out one or more of the mounting screws and install a new one incorporating a fresh bulb.
The screw itself includes a shank portion merging into a reduced diameter threaded portion. The shank portion includes a cutout on one side cradling a light bulb so that light is emitted laterally from this side relative to the axis of the screw. Suitable conductive slip rings circumferentially extend over the opposite side of the shank portion in axially spaced relationship to each other. When the screw is inserted in the front of the instrument flange, an automatic connection is effected from a power source to the light bulb through the slip rings.
The invention also contemplates a novel light wedge for distributing the light from the bulb within the screw uniformly over the instrument so that improved internal illumination results.
BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the invention will be had by now referring to a preferred embodiment thereof as illustrated in the accompanying drawings in which:
FIG. 1 is an exploded perspective view of an aircraft instrument and panel portion wherein the novel mounting screw is utilized for providing internal illumination for the instrument;
FIG. 2 is a rear elevational view of the front mounting flange portion of the instrument of FIG. 1 taken in the direction of the arrows 22;
FIG. 3 is a fragmentary cross section taken in the direction of the section line 3--3 of FIG. 2;
FIG. 4 is a side elevational view of the mounting screw of the invention;
FIG. 5 is a perspective view of a light wedge in accord with a further feature of the invention; and,
FIG. 6 illustrates a modified conventional type of light wedge which may be utilized with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1 there is illustrated an instrument casing structure including a rear cylindrical portion 10, mounting flange portion 11, and cover I2. The cover 12 mounts a front glass window I3 through which a dial I4 is visible. A panel P includes a registering circular opening 15 such that when the instrument is mounted to the rear of the panel, the dial will be visible through this opening.
Normally, the mounting flange l1 and cover 12 will include registered screw openings such as indicated at l6, 17, I8, and 19 in turn registering with panel openings 20, 21, 22, and 23. The instrument can thus be secured to the rear of the panel by inserting mounting screws through these registered openings.
Thus far, the structure described corresponds to conventional type instruments and mountings. when it becomes necessary to change one of the internal dial illuminating bulbs, the four mounting screws must be removed and the entire instrument separated from the back of the panel. The front cover can then be removed and the bulb replaced. This operation is very expensive and time consuming. Further, it would be unsafe and difficult to effect such a bulb change during flight.
In accord with the present invention, at least one and preferably two of the mounting screws for the instrument is uniquely designed to incorporate the dial illuminating bulb. Thus, as shown in FIG. I there is illustrated at 24 such a mounting screw receivable through the registered openings 20 and 16. A resilient type locknut 25 cooperates with the screw 24 to hold the instrument to the panel. As will be described in greater detail subsequently, the screw 24 incorporates in one side a miniature light bulb such that when the screw is inserted through the panel into the instrument opening, proper illumination of the dial takes place. Accordingly, it is only necessary to remove the screw and replace it with another screw incorporating a fresh light bulb should the lighting fail. This operation can be easily carried our while in flight if necessary without the necessity of disassembling the instrument or separating it from the panel.
Referring now to FIG. 2, details of the improved internal lighting system will become evident. In FIG. 2, there is shown a rear view of the cover I2 of FIG. I as it would appear if it were removed from the instrument and viewed from the rear. As shown, the upper corners include slightly recessed areas 26. In the preferred embodiment of the invention, a novel comer light wedge 27 of translucent light conducting material is positioned in this recess and cooperates with the light bulb in the screw when the same has been received through the cover member. A brush assembly 28 from which extend two resilient brushes 29 and 30 serves to provide electrical current to the bulb within the screw when the screw is mounted through the opening. A similar brush assembly arrangement is provided for the cover opening 17 on the other upper corner of the cover member. The output leads for connection to a source of electrical energy to energize the bulbs are illustrated at 31 and 32.
In the side view of FIG. 3, the axially spaced relationship of the brushes 29 and 30 adjacent to the inner edge of the bore opening I6 is clearly illustrated. In this view, the arrangement of the nuts 25 for receiving the threaded portion of the screw is also clearly shown. It will be noted that the nut is permanently secured to the rear of the flange portion I1 and includes a small threaded area in a rear diaphragm like portion. The arrangement is such that the rear diaphragm like portion. The arrangement is such that the rear surface of the nut 25; that is the peripheral portion about the threaded opening of the nut may resiliently flex inwardly as the screw is tightened. This arrangement permits the rotational position of the screw to be oriented in a desired direction without affecting the integrity of its holding power.
Referring now to FIG. 4 further details of the screw 24 will become evident. As shown, the screw includes a shank portion 33 merging into a reduced diameter threaded portion 34. The shank portion includes a cutout 35 on one side for cradling a light bulb 36. The filament for the light bulb connects to conduetive sliprings circumferentially extending over and substantially flush with the opposite side of the shank portion as indicated at 37 and 38. These sliprings are insulated from each other and from the shank portion of the screw. When the screw is assembled in the opening 16 of the cover of FIG. 2 and oriented so that the cutout is facing radially inwardly towards the dial, the slip ring brushes 29 and 30 will properly engage the slip rings 37 and 38 so that energy can be supplied to the bulb.
Referring now to FIG. there is illustrated in greater detail one of the comer light wedges such as the wedge 27. As shown, the wedge comprises light conducting material having a thickness corresponding substantially to the axial length of the cutout in the shank portion of the screw and an arcuate rear edge surface 39 substantially designed to cover the cutout portion of the screw when the elements are assembled. The front edge surface of the light wedge 27 is indicated at 40 and is preferably arcuate with a radius of curvature greater than the rear arcuate edge 39. However, this front edge surface 40 could be flat.
The, side edges of the corner light wedge between the ends of the rear and front arcuate edges are straight and at right angles to each other so as to nest within the particuiar flange structure illustrated. These side surfaces include an internal reflective coating so that light conducted by the corner wedge is reflected from the rear surfaces to all pass out the front arcuate surface and provide substantially uniform illumination over a given quadrant of the dial for the instrument.
FIG. 6 illustrates an alternative type of light wedge 43 corresponding to conventional types of light wedges except for extended portions 44 and 45 surrounding the cutouts for distributing light from the sources over the dial surface.
OPERATION Most aircraft instruments and other types of instruments have standard mountings or screw openings some place adjacent to the dial of the instrument. Thus, there is really no necessity for having to effect any major modification of the instrument itself or the panel. It is essential, however, to provide the corner recess such as described at 26 in the comers of the covers or flanges where the screw openings occur to provide communication between one side of the opening and the interior space between the front window glass and dial. The brush assembly for cooperation with the sliprings is inserted in part of the recess to position the brushes 29 and 30 as described. Otherwise, no other modifications are necessary so it will be evident that present instruments may be adapted to the invention. Either the corner light wedge structure described in FIG. 5 or the modified type of conventional light wedge 43 of FIG. 6 may be utilized without necessitating further modifications.
The instrument is mounted in the usual fashion with conventional mounting screws except for at least one of the screws which incorporates the light bulb. In the particular embodiment illustrated in FIG. I, it is preferable to provide two light bulbs at the upper left and right hand corners. Thus, screws such as the screw 24 are substituted for the conventional type screws and tightened within the screw openings. Because of the resiliency of the rear portion of the nut 25, the screw may be rotated as necessary to direct the small arrow on the head of the screw as illustrated in FIG. I in a direction pointing radially inward. This orientation assures that the cutout on the shank portion of the screw is directed inwardly so that the light will be properly directed. Further, this orientation assures proper positioning of the sliprings for engaging by the brushes 29 and 30 as described in FIGS. 2 and 3.
After the instrument has been assembled which assembly can easily be done from the front of the panel, there is never any necessity for disassembling the instrument or removing it from the panel in order to change a light bulb. All that is necessary is to remove the screw containing the light bulb and simply bodily substitute in another screw incorporating a light bulb in accord with the invention. This operation can be done during flight of the aircraft if necessary.
From the foregoing description, the advantages of the present invention will be immediately evident. First and foremost, access is enormously simplified since, as described, a bulb may be changed directly from the front of the panel without any necessity of disassembling the instrument itself or removing it from the panel. Such convenience results in a considerable savings in labor costs and maintenance expenses. Further, a bulb change can be effected far more rapidly than has been possible heretofore.
Second, no major modification is required of conventional instruments except for the small provision of recesses to provide communication between the screw holes and the space between the dial and glass and the incorporation of the brushes for providing current to the bulb when the screw is inserted. None of the exterior dimensions of the instrument is affected by such modifications. Further, conventional type light wedges may still be used, such wedges preferably being modified slightly to provide good light conductivity from the bulbs as by means of the extended side portions 44 and 45 as described in FIG. 6. The use of either the light wedge of FIG. 6 or the corner light wedge described in FIG. 5 assures excellent uniform dispersal of light over the entire face of the dial when a screw is used in each upper corner. I
It should be understood that while an aircraft instrument has been described, the invention is applicable to any type of instruments having a dial which requires internal illumination and wherein there is normally provided a screw hole for a mounting screw or an assembly screw adjacent to a side of the dial.
From the foregoing description, it will be evident that the present invention has provided a greatly improved internal lighting system for instruments wherein the difficulties in bulb changing characterizing prior art devices have been wholly eliminated.
What is claimed is:
l. A mounting screw for an instrument, said screw having a shank portion merging into a reduced diameter threaded portion, said shank portion including a cutout on one side; a light bulb cradled in said cutout to emit light laterally from said one side relative to the axis of said screw; and conductive sliprings circumferentially extending over and substantially flush with the opposite side of said shank portion in axially spaced insulated relationship to each other and the shank portion of said screw, and connected to said bulb for passing current to said bulb.
2. The subject matter of claim 1, including a corner light wedge of light-conducting material having a thickness corresponding substantially to the axial length of said cutout in said shank portion of said screw and an arcuate rear edge surface substantially covering said cutout and a front edge surface, the side edges between the ends of the rear and front edges being straight and at right angles to each other and including an internal reflective coating whereby said light is uniformly dispersed over a given quadrant by said corner light wedge.
3. in combination with an instrument having a forwardly facing dial and surrounding casing structure with at least one screw hole to one side of said dial with its axis substantially normal to the plane of said dial, a screw receivable in said hole from the front of said instrument, said screw having a shank portion incorporating a light source for emitting light laterally relative to the axis of said screw whereby when said screw is received in said screw hole said dial is internally illuminated.
4. The subject matter of claim 3, including light wedge means within said casing structure for coupling light from said source and distributing it over an area for substantially uniformly illuminating said dial.
5. The subject matter of claim 4, in which said light wedge means comprises a corner light wedge of light-conducting material, said shank portion of said screw having a cutout in one side from which said light emanates, said light wedge having a thickness corresponding substantially to the axial length of said cutout and having an arcuate rear edge surface substantially covering said cutout and a front edge surface, the side edges between the ends of the rear and front edges being straight and at right angles to each other and including an internal reflective coating whereby said light is uniformly dispersed over a given quadrant by said corner wedge.
6. In combination with an instrument having a front forwardly facing dial and surrounding mounting flange with mounting screw holes for securing the instrument to the rear of a panel in registration with a panel opening through which said dial may be seen from the front of said panel, at least one mounting screw receivable in one of the screw holes in the mounting flange by passing the same through a registered hole in the panel from the front of the panel to one side of said dial, said screw having a shank portion incorporating a light source for emitting light laterally relative to the axis of said screw whereby when the screw is received in the screw hole it serves a dual function of securing the instrument to the panel and internally illuminating the dial.
7. The subject matter of claim 6, in which said shank portion of said screw has a cutout in one side from which said light emanates, said light source comprising a light bulb cradled in said cutout to emit light laterally from the one side relative to the axis of the screw; and conductive slip rings circumferentially extending over and substantially flush with the opposite side of said shank portion in axially spaced insulated relationship to each other and the shank portion of said screw, and connected to said bulb for passing current through said bulb.
8. The subject matter of claim 7, including a corner light wedge of light-conducting material having a thickness corresponding substantially to the axial length of said cutout in said shank portion of said screw and an arcuate rear edge surface substantially covering said cutout and an arcuate front edge surface of substantially greater radius of curvature than said rear surface, the side edges between the ends of the rear and front arcuate edges being straight and at right angles to each other and including an internal reflective coating whereby said light is uniformly dispersed over a given quadrant of said dial by said corner light wedge.