US3548186A - Reading lamp shield - Google Patents

Description

Dec. 15, 1970 w. B. BROCK 3,548,186

READING LAMP SHIELD Filed Jan. 24, 1968 FIG. 5 INVENTOR WALTER B. BROCK BY J ITTORNEY United States Patent 3,548,186 READING LAMP SHIELD Walter B. Brock, RD. 1, Victor, NY. 14564 Filed Jan. 24, 1968, Ser. No. 700,184 Int. Cl. F21v 11/18 US. Cl. 24046.03 Claims ABSTRACT OF THE DISCLOSURE An inverted cup-shaped enclosure having a plurality of angularly-spaced, axially-extending slots is mounted around the light bulb of a lamp. A second inverted cupshaped enclosure having an equal number of angularlyspaced, axially-extending slots surrounds the first enclosure. When the light bulb is out, the slots of the two enclosures are out of register. When the light bulb is turned on, however, the heat of the bulb warms up a bimetallic spiral spring which connects the two enclosures, so that gradually one enclosure is rotated relative to the other. Thus, the light given off is gradually increased to permit a persons eyes to accommodate to the illumination. In a second embodiment of the invention, there is but one bulb enclosure. It has louvers instead of slots; and as the lamp warms up the bimetallic spiral spring, the louvers are opened gradually to increase the illumination produced by the lamp.

This invention relates to lamps, and more particularly to a novel device for automatically controlling the intensity of light that is initially transmitted by an electric reading lamp, or the like, each time it is turned on.

Most people are acquainted with the disagreeable, sometimes dangerous experience of being momentarily blinded, when it is necessary to turn on a light or lamp in a dark room in the middle of the night. The shock to the eye, when the retina is exposed suddenly to the light, is not only uncomfortable, but can be harmful; and the momentary blindness, if repeated often enough, could eventually lead to permanent impairment of vision. Morevore, during the period of time it takes for a persons eyes to become accustomed to sudden, bright light, the person may collide with furniture, doors, etc., and hurt himself.

The primary object of this invention is to provide a relatively simple, safe and inexpensive lamp bulb shield or dimmer, which will prevent momentary blindness, when a light is suddenly turned on in a dark room.

Another object of this invention is to provide a novel device for automatically controlling the intensity of the light transmitted by an electric lamp, so that when it is first turned on, the lamp will shine with less than full intensity and will only graduallyreach its full illuminating capacity.

A more specific object of this invention is to provide a shield or dimmer, which surrounds an electric light bulb to minimize the quantity of light transmitted when the bulb is initially turned on, and which responds to an increase in the heat of the bulb to increase the quantity of light transmitted thereby.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawing.

In the drawing:

FIG. 1 is a perspective view of a lamp incorporating an automatic light shield or dimmer made in accordance with one embodiment of this invention;

FIG. 2 is a longitudinal sectional view on an enlarged scale taken through the axis of this shield;

FIG. 3 is a sectional view taken along the line 33 of FIG. 2 looking in the direction of the arrows;

FIG. 4 is a perspective view of a modified light shield or dimmer made in accordance with a further embodiment of this invention, and showing the shield in its closed or dimming position;

FIG. 5 is an enlarged sectional view taken along the line 5-5 in FIG. 4 looking in the direction of the arrows; and

FIG. 6 is a sectional view on the same scale as FIG. 5, and take along the line 6-6 in FIG. 5 looking in the direction of the arrows.

Referring now to the drawing by numerals of reference, and first to the embodiment illustrated in FIGS. 1 to 3, 10 denotes a conventional lamp comprising abase portion 12, and aconventional shade 14, which may be mounted on thebase 12 in any known manner. Supported on thebase 12 within theshade 14, and surrounding the lamp bulb (not illustrated), is adimmer 16 comprising an inner cylindrical sleeve orshield 18, and an outer coaxial cylindrical sleeve orshield 20.

Shield 18 is open at its lower end, and is closed at its upper end by an integral,transverse end wall 22, which has centrally thereof a reduceddiameter cap portion 23 that projects slightly above (FIG. 2) the remainder ofwall 22 coaxially thereof. Intermediate its ends theshield 18 is provided with a plurality of axially extending,identical slots 24, which are equi-angularly spaced from one another about the axis ofshield 18. Secured at their upper ends in a conventional manner to the inside of thecap portion 23, and projecting downwardly intoshield 18 are two, conventional, bulb-grippingwire loops 26, which may be used to removably support theinner shield 18 on the lamp bulb in a known manner. The upper, closed end of theshield 18 is provided with a plurality ofcircular holes 28 to allow heat from the lighted bulb to pass upwardly through the shield.

Theouter shield 20 is also open at its lower end, and is closed at its upper end by an integral, steppedtransverse wall 30, that has a reduced-diameter axial extension orcap portion 32, which overlies thecap portion 23. Intermediate its ends theouter shield 20 is also provided with a plurality of axially extending, angularly spacedslots 34, which are identical in number and shape to theopenings 24 in theinner shield 18. The closed, upper end of theouter shield 20 is also provided with a plurality ofcircular openings 36 for exhausting heat from the top of the dimmer.

Interposed between thecap portions 23 and 32 of the inner andouter shields 18 and 20, is a heat-responsive,bimetallic coil 38, which surrounds the reduced diameter portion ofcap portion 23 and has one end secured to the outside of said cap portion and has its other end secured to the inside of thecap portion 32.Coil 38 is secured to thecap portions 23 and 32 in such manner that, when the assembleddimmer 16 is at room temperature, theouter shield 20 is positioned so that itsslots 34 are out of registry with theslots 24 in theinner shield 18.

Theshields 18 and 20 may be made from, for example, a metal, plastic or fabric material, or combinations thereof.

In use thedimmer 16 is supported, for example by thewires 26, on a lamp bulb, which is secured in the conventional bulb socket on top of thelamp base 12. Assuming that the bulb is turned 01f, and that thedimmer 16 is at room temperature, the sleeves orshields 18 and 20 will be in the relative positions illustrated in FIG. 3 with solid portions ofshield 20 registering with theslots 24 insleeve 18, so that when the lamp is first turned on, substantially most of its light will be prevented from passing radially through theslots 24 and 34 ofsleeves 18 and 20. This amount of light will be relatively small in comparison to the amount normally transmitted by a conventional lamp, and will in no way cause discomfort to a persons eyes. However, as soon as thelamp 10 is turned on, the heat from its bulb begins to warm thebimetallic coil 38, so that the coil will cause theouter shield 20 to be rotated relative to theinner shield 18, to bring theslots 34 gradually into registry with theslots 24. Thus gradually the amount of light that is allowed to pass radially outwardly through thedimmer 16 is increased as a persons eyes gradually accommodate themselves to the light.

If a person is awakened in a darkened room, by a telephone or by a babys cry at night, for instance, and turns on the light switch, a lamp that is provided with adimmer 16 will glow dimly at first, and then gradually will increase in brilliance until theopenings 24 and 34 register with one another. This occurs when the temperature of thecoil 38 has stabilized, at some temperature above room temperature. When the light is turned off, the temperature of thecoil 38 returns to room temperature, and thecoil 38 returns to the position illustrated in FIG. 3, thereby rotating theouter shield 20 back to its dimming or lightblocking position as shown in FIG. 3.

Theshield 40, which is shown in FIGS. 4 to 6, comprises alouvered enclosure 42 having anannular bottom 44, and an inverted cup-shaped top 46. In itscenter top 46 has a reduceddiameter portion 48 to which conventional bulb-gripping wire loops 26 are secured in the same manner as in the first embodiment. Betweenplates 44 and 46 there extend a plurality of angularly-spaced, parallel shafts 50 (FIG. which are rotatably journaled at opposite ends inplates 44 and 46 adjacent the marginal edges of the plates.

At its upper end eachshaft 50 has formed thereon anintegral crank arm 52, which has apin portion 53 that projects into one of a pluraltiy ofslots 54 formed in an inverted cup shapedactuator plate 56 that overliesplate 46. A heat-responsivebimetallic coil 58 is secured at one end to the exterior ofportion 48 ofplate 46, and at its opposite end to the interior ofactuator plate 56.

As in the first embodiment,plates 46 and 56 are provided with a plurality ofventing holes 61 and 62, respectively, for allowing heat from a bulb insideenclosure 42 to pass upwardly into thespace containing coil 58, and outwardly through the top ofplate 56.

Secured adjacent their inner longitudinal edges to theshafts 50 to rotate therewith are a plurality of elongate,pivotal louvers 64, which may be made of plastic, metal, fabric, etc. Eachlouver 64 is curved slightly between its longitudinal edges, so that it is arcuate in cross section; and it has an axial length only slightly less than the distance separating the top andbottom plates 44 and 46. In their closed positions (FIG. 4) thelouvers 64 are disposed in coaxial, slightly overlapping relation so that they substantially completely enclose the bulb (not illustrated) on whichshield 40 is mounted; and in their open positions (FIG. 6)louvers 64 project outwardly substantially radially of the axis of theenclosure 42 to expose the light bulb.

In use,shield 40 is mounted on a bulb in the same manner asshield 16. Normallycoil 58 holds theplates 46 and 56 in the positions shown in FIGS. 4 and 5, wherein thelouvers 64 are closed. When the lamp bulb (not illustrated) is turned on, heat therefrom actuates thecoil 58, thereby rotating plate 56 (FIG. 6) relative toplate 46. This causesslots 54 to pivot thecrank arms 52 clockwise (FIG. 6) relative toplates 46 and 44 so that thelouvers 64 are swung from their closed to their open positions.

From the foregoing it will be apparent that applicant has devised relatively simple, automatic and inexpensive dimming devices for only gradually increasing the light when a light bulb is turned on in a dark room. Thebimetallic coil 38 or 58 either winds up or unwinds as it is heated, thereby to rotate theshields 20 or 64 into and out of light blocking positions, while theopenings 28, 36, 61 and 62 in the cap positions function as ventilating apertures for allowing the transfer of heat by convection from a lamp bulb upwardly past thecoils 38 or 58 and out of the top of the shield. These perforated tops thus function as dampers or baffles, which permit flow of heat out of the tops of thedimmers 16 and 40 and which also tend to stabilize the temperature in the spaces between the inner and outer cap portions of the shields at a relatively high value, when the lamp has been turned on for an extended period of time, thereby causing thecoil 38 or 58 to maintain theshield 16 or 40 in its fully open position until the lamp is turned off.

While theapertures 24 and 34 have been shown as rectangular, it will be apparent that the shape and number of these openings may be altered without changing their function. Similarly, in place of theresilient wire loops 26, other conventional means (not illustrated) may be used to mount the dimmer 16 on thelamp 10 around a bulb. Moreover, although the lower ends ofshields 18 and 20 have been described as being open, it Will be apparent that the lower ends could be at least partially closed, provided an opening is retained for accommodating a bulb in the dimmer. Also, it will be apparent that the number and size of thelouvers 64 in the second embodiment of this invention may be varied, if desired, for different lamps.

It will also be obvious that a bedside or other lamp having shields made according to the present invention might be connected in circuit with a clock radio or other timing device so that the lamp is switched on at the same time as the radio alarm and as an electric coffee pot. A person might then be waked by the alarm (perhaps to music) and at the same time his lamp would gradually illuminate his bedroom through operation of the device of the present invention, and simultaneously also his breakfast coffee would be started percolating. The person would not have to turn on his lamp; and the device of the present invention would prevent the person from being temporarily blinded by going from darkness into full light.

While the device of the present invention may be mounted, as described on the lamp bulb, theouter sleeve 20 may be made slightly longer than theinner sleeve 18, and the outer sleeve may rest on a perforated discshaped platform or collar around the lightbulb socket, so that the weight of the mechanism plus that of the lampshade will be carried by the base .12 of the lamp rather than by the light bulb.

While the invention has been described, then, in connection with various specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. A lamp shield, comprising:

a first hollow member having therein a plurality of openings,

means on said member for removably mounting said member over a lamp bulb,

means for selectively opening and closing said openings in said hollow member to control the amount of light that can be transmitted by said bulb through said openings, including a second member mounted on said first member for limited movement between first and second positions relative to said first member operatively to effect the opening and closing, respectively, of said openings, and

a third temperature-responsive member interposed between said first and second members, and operative at room temperature normally to maintain said second member in said second position, and operative in response to increase in the temperature thereof above room temperature to move said second member toward said first position.

2. A lamp shield, comprising a first hollow member having therein a plurality of openings,

means on said member for removably mounting said member over a lamp bulb,

means for selectively opening and closing said openings in said hollow member to control the amount of light that can be transmitted by said bulb through said openings, including a second member mounted for movement in opposite directions relative to said first member to effect the opening and closing, respectively, of said openings, and

a third member interposed between said first and second members, and operative in response to increase and decrease in the temperature thereof to move said second member in said opposite directions, respectively,

said second member being mounted to rotate in opposite directions on said first member, and

said third member being a temperature-responsive coil connected at opposite ends to said first and second members, respectively, and operative to rotate said first member relative to said second member upon a change in the temperature of said coil.

3. A lamp shield, comprising:

a first hollow member having therein a plurality of openings,

means on said member for removably mounting said member over a lamp bulb,

means for selectively opening and closing said openings in said hollow member to control the amount of light that can be transmitted by said bulb through said openings, including a second member mounted for movement in opposite directions relative to said first member to effect the opening and closing, respectively, of said openings, and

a third member interposed between said first and second members, and operative in response to increase and decrease in the temperature thereof to move said second member in said opposite directions, respectively,

said first and second members comprising a pair of sleeves mounted coaxially one within the other in radially spaced relation,

said spaced openings being axially-extending slots in the annular walls of said sleeves, and

said third member being a bimetallic member secured at opposite ends thereof to the inner and outer sleeves, respectively, and operative at room temperature to position said sleeves so that their openings are out of registry, and responsive to heat from a lighted bulb in said lamp to move one of said sleeves in a direction to register its openings with those openings in the other sleeve.

4. A lamp shield as defined inclaim 3, wherein:

said sleeves are mounted for rotation relative to one another, and

said bimetallic member is a coil surrounding the inner sleeve, and responsive to predetermined changes in its temperature to rotate the outer sleeve relative to the inner sleeve.

5. A lamp shield as defined in claim 4, wherein:

said openings in the annular wall of one of said sleeves are identical to, and equal in number to, the openings in the annular wall of the other of said sleeves, and

said openings in the outer sleeve normally register with the portions of the inner sleeve that separate the openings in the inner sleeve.

6. A lamp shield, comprising:

a first hollow member having therein a plurality of openings,

means on said member for removably mounting said member over a lamp bulb,

means for selectively opening and closing said openings in said hollow member to control the amount of light that can be transmitted by said bulb through said openings, including a second member mounted for movement in opposite directions relative to said first member to efiect the opening and closing, respectively, of said openings, and

a third member interposed between said first and second members, and operative in response to increase and decrease in the temperature thereof to move said second member in said opposite directions, respectively,

said means for opening and closing the openings in said hollow member comprising a plurality of parallel louvers movably mounted on said first member for movement into and out of closed position, and

means connecting said louvers to said second member for movement thereby in opposite directions upon movement of said second member in opposite directions relative to said first member.

7. A lamp shield as defined inclaim 6, wherein:

said louvers are mounted to pivot about a plurality of parallel axes that are angularly spaced about an axis of said first member,

said second member is mounted to rotate about the lastnamed axis and has therein a plurality of radially extending slots angularly spaced about said axis, and

said connecting means comprises a plurality of pins connected to said louvers and projecting into said slots.

8. A lamp shield as defined in claim 7, wherein:

said third member comprises a bimetallic coil surrounding said axis and connected at opposite ends thereof to said first and second members respectively,

said coil being operative normally to hold said second member in a position in which said louvers are closed over said openings, and being operative upon a predetermined increase in the temperature of said coil to open said louvers.

9. A lamp shield, comprising:

a first hollow member having therein a plurality of openings,

means on said member for removably mounting said member over a lamp bulb,

means for selectively opening and closing said openings in said hollow member to control the amount of light that can be transmitted by said bulb through said openings, including a second member mounted for movement in opposite directions relative to said first member to effect the opening and closing, respectively, of said openings, and

a third member interposed between said first and second members, and operative in response to increase and decrease in the temperature thereof to move said second member in said opposite directions, respectively,

said first and second members being cylindrical and open at one end and closed at their opposite ends, and mounted on said lamp one within the other with their closed ends positioned above said bulb,

each of said closed ends having therethrough a plurality of openings for allowing air heated by said bulb to pass upwardly and out of said closed ends, and

said third member comprising a coiled, bimetallic member interposed between said closed ends, and secured at opposite ends thereof to the first and second cylindrical members, respectively, to rotate one of said members relative to the other about a common axis,

, 8 when said bimetallic member is subjected to pre- References Cited determined temperature changes. UNITED STATES PATENTS l 1b prignghieldmg apparatus for an e ectrie light bu com 2,224,726 12/1940 Finnegan, et all d 2,345,517 3/1944 Weiss 240l0.1 a movable shutter device surroundlng the bulb an 5 2,876,339 3/1959 Thome movable between open and closed positions and operative when in closed osition to limit the external illuminating effect of the bulb, and JOHN HORAN Pumary Exammer a bimetallic member disposed in juxtaposed relation to R. M. SHEER, Assistant Examiner said bulb normally to maintain said device closed, 10 when said bulb is deenergized, and responsive to the heat produced by said bulb, when illuminated, to 24() .10 move said shutter device gradually to open position.

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