US1617595A

US1617595A - Lantern

Info

Publication number: US1617595A
Application number: US516837A
Authority: US
Inventors: Clinton O Harrington
Original assignee: ALDOBILT Co
Current assignee: ALDOBILT Co
Priority date: 1921-11-21
Filing date: 1921-11-21
Publication date: 1927-02-15
Anticipated expiration: 1944-02-15

Description

Feb. 15 1927.-

C. O. HARRINGTON LANTERN 7 Filed Nov. 21, 1921 2 sheets-sheet 1 Feb. 15, 19.27. 1,617,595 v C. O. HARRINGTON LANTERN Filed Nov. 21 2, Sheets-Sheet 2 Patented Feb. 15, 1927.

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CLINTON O. HARRINGTON, CHICAGO, ILLINOIS, ASSIGNOB 'I'O ALDOBILT 'COTiIiPANY,

OLE CHICAGO, ILLINOIS, A COBTEOBATION OF I LLTNOES. 1

; LANTERN.

Application filed November 21, 1921. Serial No. 516,837.

ployed, the axis of the light projection is usually directed toward some intermediate point on the curve so that the engineer may have the effect of the signal throughout as much lateral range as the spread of light from the source permits. Such lanterns do not, however, provide a materially great.

spread except where special projecting lenses are employed; or where an unusually large source of light is used. In such special cases the objection exists of the increased costof the special construction, the increased cost of maintenance, or both. Furthermore, such practicebrings into the system special constructions at only special places, resulting in much unnecessary inconveniences. Among such special constructions are frosted lamps and frosted lenses for spreading the light and also a projecting lens provided on its outer surface with a plurality of parallel ribs. i

The principal object of the present inven tion is to provide simple, easily operated and highly efficient means associated with a source of light and its projecting lens for providing a spread of light which is relatively great, and thus improve the efficiency of the signal. A more specific object is to provide such advantageous means in a form which may be applied to lanterns now 1n use, with the said desired results. Another specific object is to provide such meansin a form which may be readily removable and replaced from time to time as desired, and

by removal of the light-spreading means provide for the efiective and convenient focusing of the lamp with respect to the lens and of the lantern as a whole with-respect to the area desired to be illuminated. Another specific object is to provide a form of light=spreading device in which interchangeability may be had to effect a greater or less spread accc -J ing to the particular situation. ,itsiioth r to provide a light sprsad 'ing device which may be positioned for operative use without any focusing operation and without a modification of the adjustments of I the lantern parts previously made. It is also an object to provide a device which is of low cost and which may be cheaply and easily installed. Other objectsfand advantages will appear hereinafter In the accompanying drawings, which form a part of this specification, Figure l is a vertical sectional View, as on theline 11 of Fig. 2, of a railway signal'lantern of conventional form having a screen device constituting .a specific embodiment of a pare ticular feature of novelty as an element or as a device in its operative position; Fig. 2 is av horizontal sectional view of the same device, as on the line 22 of Fig. 1; Fig. 3 is a sectional view .as'on the line 3-3 of Fig. 1; Fig. 4k is an enlarged fragmentary view illustrating the effect of the screendevice .andlens in refracting the rays .of "light; .5'is a fragmentary view of .a part 'of Fig. 4 on .an enlarged scale; Fig. 6 is an enlarged fragmentary sectional view showing a.

modified form of screen; Fig. 7 is a fragmentary enlarged face view of another modi fied form of screen; and Fig. 8 is afra mentary section on the line 8 8 of Fig.

The lantern body 10., the projecting: lens 11 and. the. source of light 12 mounted on a base 13 are to be understood as being of the usual or of any preferred construction. The source of light 12 is to be understoodas being at or substantially at the focus of the lens 11. Ordinarily the lamp .is mounted for adjustment in several directions so that the filament at 12 may be conveniently brought to the focal point.

The specific feature of improvement is the provision of a screen as 14 between the source .ofylight and the projecting lens.., It is not new to provide some form of screen between the lens and the lamp, and I am aware that colored screens and screens adapted to dim the light have been so positioned. The present screen device as 14 is of a different construction, however, and accomplishes adifferent result. V

The specific screen 14 sa transparent ele-' ment and may be considered a small rectangular plate of'glass having a'pl irality of vertical ribs (Figs'l and 5) thereon.

. 4. is readily removablyheld in j 17, a pair of lateral cleats 18 and a top cleat 19, each cleat'being formed to overlie the glass and hold it'upon the frame 16. Should Vit'b e desired to remove the plate as 14; the

top cleat 19 is'removed, as by removing the small screw 20 holding it in place, whereupon the plate may be lifted out of the guideways "formed by the bottom and lateral cleats, and thereupon the lantern may be used. without the screen 1n such positions as do not particularly call for it, and, lmporcated as point. lh'e parallel ribs 15 will ordinarily be Vertical as shown in, Figs. 2 and 3 since 1n railway signal work at least it will ordinarily be desired to spread the .rays in the 'sidewise or lateral directions. When it is desired to spread the light in up and down directions the screen or plate 14 may be turned so that the ribs 15 will extend 'in the horizontal directions, the plate 14 being square and fitting the carrying p frame in either position.

' drical lens. flVhile the number of these.

i lenses may vary to a considerable extent it is'preferabIe to providea relatively large Eachof the ribs'15 is a very small cylinnumber of them side by side in order to obtain the, desired uniform diffusion of light.

The. effect. of these small lenses is to bend the rays coming from the source 12 so that as the lantern is viewed from in ,front the V light appears to emanate from'a plurality -40 of sources as 12, 12 and 12 in a line, there oing; a large number of such apparent sources oflight from onesideof the field to the other. 7

Without the screen in position the rays from the true source 12 diverge in straight lines tothe lens 11. With the screen as 14 in place some of the rays diverge from the source to the lens in substantially the normal'way while for the most part they are bent "from the true normal line of divergence, the result being that from each of the projections 15 there is a multitude of diverging rays striking thelens, and these,

rays depart from the lensin a multitude of diverging directions. .So far; as the divergence of the. rays is concerned the effect is that of many independent sources of light.

Turning to Fig- 6 the plate 23 has a plurality of parallel rib-like projections 24 also constituting lenses. These ribs are shown ashaving a concave surface'thereby bending the raysdivergingly. The ribs 24 may be inclined'in one direction only, as illustrated, instead of being symmetrical with respect to the optical axisof the lens, in which'case the light will be diflused chiefly one side have their direction changed in a greateror less degree. depending upon the angle between the tace of the rib and the back of the plate. lVith such a construction the optical axis of the lantern may be directed at a distant po nt on a railway curve, and with lateral diffusion taking place pr1nc1- pally on one side of the axis the light from the lens will be diverted so as to cover the portions of. the curve nearer' to the lantern as desired. V I i If it should be. desired to spread the rays in all directions instead of merely horiZontallyor vertically a lens screendevice such as shown, for example, in Figs. 7 and 8 may be employed, in which case the plate 26 is provided on one surface with a plurality of' small spherical lenses 27, the efl'ect of which screen to the lens as though there were an individual source of li ht at a multitude of points as viewed from in front of the lens, with a consequent wide spreading of the rays in all directions.

illustrated are highly efficient for the purposes indicated, the invention is-not l1m1ted to the specific characters of the particular screen elements illustrated herein, and refincrease of spread in given directions.

2. In a signallantcrn, the combination of a projecting lens, a source of light for roj ecting rays therethrough, and ght-refracting means between the lens and the source of light comprising a substantially transparent plate on one. surface ot'which are a plurality of relativelysmall light-dispersing elements for givingthe rays emanating from the lens a materially greater increase of; spread in given directions. a r

3. In asigna-l lantern, the combination of a projecting lens, a source of light for projecting light therethrough, and'light-refracting means between the lens and the source of light comprising a' substantially transparentplate on one surface of which are a pluralit v of relatively long and narrow light-dispers While the forms of lens screens specifically 90 is to cause the rays to emanate from the ing projections for giving the rays emanating from the lens a materially greater increase of spread in given directions than in other directions.

4. In a signal lantern, the combination of a projecting lens adaptedto project rays of light from an associated source in a substantially circular path in cross View, a source of light for projecting light through the lens, and light-retracting means between the lens and the source of light comprising a substantially transparent plate on one surface of which are a plurality of relatively long and narrow substantially straight and parallel light-dispersing projections adapted to increase the spread of light in given directions whereby the lightrays from the source define a path of lightwhich is'elongated in cross View.

5. In a railway signal lantern of the character described, the combination of a projecting lens, a concentrated source of light substantially at the focus of the lens, and light-retracting means between the source of light and the lens, and materially spaced from each thereof, for giving the rays emanating from the lens a materially greater increase of spread in given directions.

6. The combination of claim 5 hereof in which said light-refractingmeans are in the form of a substantially transparent plate having light-dispersing elements thereon.

CLINTON O HARRINGTON.