US2551028A - Lamp changing apparatus - Google Patents

Description

May 1, 1951 Filed Oct. 5, 1946 J. R. MaCKAY 2,551,028

LAMP CHANGING APPARATUS 8 Sheets-Sheet l lll May l, 1951 J. R. MaCKAY 2,551,028

LAMP CHANGING APPARATUS Filed Oct. 5, 1946 8 Sheets-Sheet 2 May 1, 1951 R MaCKAY 2,551,028

LAMP CHANGING APPARATUS Filed 00T.. 5, 1946 8 Sheets-Sheet 3 7072 2i ILIVIfu-Iiag/ A( May 1, 1951 J R, MaCKAY 2,551,028

LAMP CHANGING APPARATUS Filed OCt. 5, 1946 8 Sheets-Sheet 4 May 1, 1951 l J. R. MaCKAY 2,551,028

LAMP CHANGING APPARATUS Filed Oct. 5, 1946 8 Sheets-Sheet 5 May 1, 1951 8 Sheets-Sheet 6 Filed Oct. 5, 1946 J. R. MaCKAY LAMP CHANGING APPARATUS May 1, 1951 8 Sheets-Sheet 8 Filed Oct. 5, 1946 Eig. Il

vorey Patented May l, 1951 LAMP CHANGING APPARATUS John R. MacKay, Packanack Lake, N. J., assignor to Wallace & Tiernan Products, Inc., Belleville, N. J., a corporation of New Jersey Application ctober 5, 1946, Serial N0. 701,429

13 Claims.

My present invention relates to lampchanging apparatus for automatically replacing an electric lamp which has failed. The invention, while having general utility, has been made especially for beacons, such as aviation and marine beacons, or other signal devices using comparatively high wattage lamps, which are successively positioned with their centers of illumination at a predetermined point. This point is usually the focal point of a lens or lens system, such as a Fresnel lens or other optical apparatus, and wherein the space requirements permitting the interchange of lamps is such that a peculiar and novel type of lamp interchanging means is desired in order to adapt the lampchanging apparatus to a lens system which is of minimum size permitting lamp interchange.

The invention aims to provide an improved lampchanging apparatus especially suitable for the uses aforesaid, which shall be of comparatively simple and rugged construction and very reliable in operation; which shall function to replace a failed lamp rapidly and to position a new lamp accurately; which shall eiect the replacement operation smoothly and without harmful jarring and which shall maintain the positioned lamp accurately in position regardless of vibration and other causes of damage.

Considering the invention from the point of View oi its use with a Fresnel lens system, a minimum size lens system permitting the interchange of large wattage lamps such, for example, as LPS-52 envelope lamps, and also PS-40 envelope lamps, requires that the inside diameter of the lens system be slightly more than twice the outside diameter of the lamps to be used therewith, so as to permit one lamp to be withdrawn from its operative position while another lamp is being moved to its operative position in accordance with the present invention, otherwise it would be necessary to move the lampchanger apparatus, or the lens system, or both, bodily, which is undesired in a practical installation. The provision of a lampchanging apparatus which will eiect the above purposes by moving the lamps to and from their respective operative positions is a primary object of the present invention.

Among the further and more detailed objects of the present invention are to provide lampchanger apparatus as aforesaid, wherein at least two lamps are mounted upon a rotatable carrier and are moved, primarily by the rotation of that carrier and secondarily by a movement in respect to the carrier under control of a cam system, to eiect the desired results aforesaid. In this con- (Cl. 24U-37.1)

nection it is a detailed object of the invention to provide an interchangeable cam having cani surfaces respectively arranged for association with each of at least two lamps as aforesaid, and wherein the coniigurations of Ythese cam surfaces are determined by taking into account the space requirements or restrictions upon movements ofl the parts, and the dimensions of the lamps in question as to shape and size, so as to effectv the desired results aforesaid.-

A further specific object of the invention in connection with the above is to provide means by which the lamps are positively prevented from being moved in such manner as to engage or collide with one another during lamp interchanging movement,` while still operating in a system having minimum dimensions as aforesaid.

A further specic object of the invention is to provide lampchanging apparatus wherein the actuating energy for lamp interchange is derived from a potential energy storing means, such as a'spring or weight, and wherein there is an escapement means to limit the rate of movement of lamp interchange to a safe value, while permitting rapid resetting of the apparatus to its initial position withoutv regard to movement or time requirements therefor of the escapement mechanism, which is` normally employed during the automatic vlamp interchange.

Further detailed objects of the invention in this connection are to provide for the elimination of friction in an automatic release means for the lamp interchange mechanism, so as to insure satisfactory operation underV severe conditions to which the mechanism may be subject in use, and wherein maintenance is relatively infrequent due to the inaccessibility of some of the places where devices of the kind herein disclosed may be installed.

A further object of the present invention is to provide modiiied forms of means in respect to that above generally referred to for affording a peculiar and novel type of non-parallel movement as between the lamp bases and the lamps themselves on the one hand, and the lamp carrier on the other hand. The purpose of this is to provide for the adaptation of standard types oi lamp carrier mechanisms used on commercial lamp changing devices to enable them to accommodate extra large lamps of the types known as Pis-40 or PS-52 above referred to. When these extra large lamps are used with certain now standard lamp changing equipment, it has been .found that they will interfere with the movements of this apparatus due to their large size. However, by relatively simple changes in the equipment in accordance with the present invention, it can be made usable with these special lamps by providing a non-parallel motion mechanism between the carriers and the lamps, so that as the carrier rotates, the lamps are not held permanently vertical or at any other one angle, but their angle is progressively varied in response to the rotation of the carrier. The provision of such an apparatus, while constraining the lamps to movement in a single Vertical plane, is therefore a further detailed object of this invention. p l

Other and more detailed objects of the present invention will become apparent from the following description of preferred embodiments thereof and from the appended claims, when considered in connection with the accompanying drawings, in which:

Figure l is a view principally in elevation, but with a Fresnel lens associated therewith in vertical section, showing certain parts of the lampchanging apparatus in its normal position in full lines and at an intermediate position in dotted lines;

Fig. 2 is a similar view of most of the apparatus of Fig. l on a larger scale to show some of the details thereof;

Fig. 3 is a view of the parts taken from the rear in respect to the direction in which they are shown in Figs. l and 2, illustrating the actuating mechanism inside the case with the cover removed;

Fig. 4 is a view similar to Fig. 3, but taken at right angles thereto. with the case in vertical section, but parts contained therein substantially in elevation;

Fig. 5 is a View substantially in horizontal section on the line 5-5 of Fig. 2 showing the internal construction of the hub portion of the lamp carrier;

Fig. 6 is a detailed sectional view on an enlarged scale taken substantially on the line 6-5 of Fig. 2;

Fig. '7 is an enlarged fragmentary detailed view illustrating the escapement mechanism and the pawl and ratchet devices associated therewith, taken substantially on the line l-l of Fig. 5.

Fig. 8 is a fragmentary detailed View in vertical section showing the escapement mechanism and drive therefor, taken substantially on the line 8 8 of Fig. 5;

Fig. 9 is a diagrammatic view illustrating the wiring diagram' and electrical connections for Y" the apparatus and certain of the mechanical actuating means substantially in perspective showing the mechanical and electrical operation of the entire apparatus;

Fig. l0 is a view partly in elevation and partly in vertical section of a modied form of the invention; and

Fig. 1l is a diagrammatic view of the form of the invention shown in Fig. l0 in conjunction with a lens system and illustrating various positions of the parts incident to the movement thereof.

The apparatus of my present invention is in elfect an improvement on that shown in my prior Patent No. 2,289,315, granted July 7, 1942, entitled Signal Device in that it includes all, or substantially all, the desirable characteristics of that device and in addition provides several novel features including a lampchanging apparatus which can accommodate itself to the handling Qi.

larger size lamps with a minimum size of lens system due to certain peculiar and novel structural provisions hereinafter particularly disclosed.

While it is possible to provide a lampchanging system where there are more than two lamps and to provide means whereby when each lamp in succession burns out or otherwise fails, the next lamp in succession is moved intov position to replace the failed lamp, I have chosen to illustrate the present invention as applied to an apparatus wherein there are but two lamps, one being a principal or working lamp, which is normally at a position such that its center of illumination will loe at a preedtermined point, which is usually the focal point of a lens system, such as a Fresnel lens l, and the other, a spare or auxiliary lamp for use in the event that the principal lamp fails. As shown in Fig. l, a principal lamp 2 is at its operative position in which its center of illumination is located at the point 3' which is at the focal point of the' lens i. At this position, the auxiliary lamp designated ai is in effect out of any position wherein it will interfere with the effective use of the principal lamp 2.

It is desired, upon the failure of the lamp 2, to move it to an inoperative position and to move the lamp 4 to a position such that its center of illumination will be at the point 3, and particularly to effect this movement in such a way that the lamps 2 or 6l will not be permited to Contact with any part of the lens system l or with each other during their movement. To effect this result, the lens system must have an inside diameter slightly more than twice the outside diamter of the lamps 2 and ll, so the lamps 2 and i may be able to pass one another as in the positions shown in dotted lines in Fig. l. Such an operation is unattainable with any mechanism or apparatus to be found in the prior art to the best of my knowledge, as in most such prior art structures the lamps are moved about a single xed center or by a straight parallel motion device asi shown, for example, in my Patent No. 2,289,315, the latter device being preferable but still requir-r ing a lens system of greater diameter than that required in accordance with the present invention. It is desired that the lamps be carried upon a single lamp carrier structure which in the present instance is generally designated at 5, and which is, in accordance with the present invention, rotatable about a substantially horizontal axis in respect to a suitable support. It is necessary in eecting the desired results cf the present invention to control accurately the angular position of each of the lamps in respect to the lamp carrier or, from a broader point of view, to control the relative positioning of each lamp in respect to the carrier throughout its movement. This control is preferably peculiar to each lamp and so constructed and arranged, as by the inclusion of a cam mechanism designed for the particular size and shape lamps to be employed, that the desired general results above set forth will be attained.

In conjunction with the above, there must be means for controlling the position of each lampA accurately at its operative position, for controlling the position of the carrier at each of its'l positions at which a lamp is located at its operative position, for actuating the carrier to move it from its normal to its auxiliary position in the event of failure of the principal or working lamp shown at 2 to its other terminal position, and to PlFOVde. i0? the resetting of the apparatus upon the replacement of the principal lamp, in addition to other electrical and mechanical means for carrying out the aforesaid general purposes. These means will be described in detail hereinafter.

Turning now more particularly to the accompanying drawings, and especially to Figs. l to 5, inclusive, thereof, there is provided a supporting structure here shown as a case 5, which may be a suitable metal casting and which may be secured in any desired manner, as by bolts l, passing through slots or elongated operings 8 (Figs. l, 2 and 5) formed in lateral extensions of the case 5, to any suitable support here generally designated at 9, which be any structural part on which the apparatus may be mounted. A set up adjustment of the position of the lamps in a direction perpendicular to the plane of the paper (Figs. l and 2) may thus be effected by adjusting the entire device in this direction and securing the adjustment by the bolts l.

The case may be provided with a suitable cover if: secured thereto as by a plurality of screws Il in the form of nuts threaded on bolts I2. which are suitably, rigidly secured in parts rigid or integral with the case it `The parts 5 and lil thus provide a hollow chamber in which most of the electrical and mechanical actuating means for the device may be enclosed as best shown in Fig. 4.

suitably supported in the case is a sleeve member I3 (Fig. 5) which passes through a hole in a boss i4 and has a iiange bearing against the outer end of this boss. The member I3 is nonrotatably secured in position by a nut I5 threaded on the end of the portion of the member I3 extending inside the case 6 as shown. This secures the member I3 non-rotatably to the case B and serves to determine the axis of rotation of the lamp carrier 5 concentric with the axis of the member I3.

Turning now to the construction of the lamp carrier or carrier structure 5 per se, this carrier comprises a pair oi similar cross arm members l5 and il which are provided with apertures at their mid-point to surround portions of the sleeve member i3. These members are connected together by a hub structure including a pair of annular members i3 and I9 which may be secured together by a sleeve welded or otherwise secured to the members i8 and I9. The members i? and I9 are connected together by a plurality of bolts 2i and the members it and I8 by a plurality of b -ts 22, as shown (Fig. 5). Suitable bearing sleeves, as shown at 23 and 24 may be interposed between the inside of the central openings of the arms le and l 'I and adjacent portions of the sleeve member I3 to minimize friction. These bearing members are preferably of the selflubricating type such as metal-impregnated graphite, which is also preferably used for all bearings liable to be subjected to the heat of the lamps so as to provide the necessary lubrication without the use of ordinary lubricants, which tend to become gummy in use at the temperatures existent. The lamp carrier 5 is prevented from axial movement upon the sleeve member i3 by reason of the member 23, which is rotatable with the carrier 5 and which bears against the outer end surface of an annular flange forming a part of the boss lil of the case 6. Outward movement of the carrier 5 is similarly prevented by a portion of the arm 6 surrounding the central opening therein bearing against a flange 25 of the sleeve member i3 as best shown in Fig. 5.

Eachv of the lamps 2. andV 4 is supported by the lamp carrier structure 5 at a point spacedfrom the center of rotation thereof by the same predetermined amount, these lamp supporting means being essentially similar to one another so that only onewill be described in detail.

Referring now principally to Fig. 4, a movable lamp supporting means 251m the form of a substantially U-shaped bracket is provided having integral or rigid pivot pins or projections 21 and 28 thereon. These pins or projections are shown as formed with a larger diameter cylindrical portion fitting inbearing apertures near the ends of the arms l5 and il and smaller diameter concentric pin portions extending therefrom for purposes hereinafter set forth. It will be understood that the pins or projections Zland 28 are in axial alignment with one another, so that in practice each lamp is rotatable in respect to the carrier 5 about a horizontal axis which is parallel to the horizontal axis of the carrier itself. The lamps as shown are located at diametrically opposite points on the carrier 5. Each of the lamp supporting means 25 is arranged to support a Suitable socket 29, which may be of any desired commercial type suitable for the type lamps to be used and which is in turn suitably secured to a base plate 35i in any usual or desired manner. The plate lf is supported from the means 26 preferably at three equidistantly spaced points by an adjustable spring device formed as by providing threaded pins lextendingdcwnwardly from the plate 35i and passing through suitable bosses 32- to receive thereunder suitable nut or lock nut means helical compression springs 34 being provided about each of the pins 3I between the underside of the plate 3Q and the inside of the bosses 32 Thus, by suitable adjustment of the nuts 33 on the pins 3l, the position of the lamps, particularly to determine the respective operative positions thereof, can be accurately and finely adjusted in directions both in and perpendicular to the plane of the views shown.

Means are provided, preferably including cam means peculiar to each of the lamps 2 and il, for independently controlling their angular positions in respect to the carrier 5. For Vthis purpose there is provided a plate type cam 35, which is stationary but removably and interchangeably mounted upon the supporting structure, in this case-upon the case 5', by means of a plurality of screws as shown at 35 which pass through the cam and are threaded into bosses formed on the outside of the case t as bestshown in Fig. 4. As shown in Figs. l and 2, the right-hand side of the cam 35 is formed with a cam surface 31 for controlling the position of the lamp 2 while the left side has a surface 38 for controlling the position of the lamp Cooperating with these cam surfaces areV followers respectively associated with each lamp, these followers comprising rollers sand arms ls, the latter of which are suitably secured at their upper ends, as by a suitable set screw or taper pin, to the smaller diameter portion of the pins 23 extending inwardly from the arm I6 (to the left as seen in Fig. 4).

En order to retain the respective cam rollers against the cam surfaces 3l' and 38, means are rovlded, preferably including mechanical interlocking means and a spring means, which are interconnected between the two lamp supporting structures for reasons appearing hereinafter. rEhese means include an arm 4I, secured as by a set screw to the outwardly extending, small diameter portion of' each ofthe pins 2l, the lower ends of the arms di being connected together by means including shackle portions i2 pivoted to the arms 4| and rods 63 threaded thereinto by adjustable amounts and a barrel spring device generally indicated at 44, this device being shown in detail in Fig. 6. As shown in that figure, the right-hand rod 43 is threaded in one head i5 of the barrel spring device lili, this head being in turn threaded on a cylinder or sleeve portion 45 thereof, which has threaded on its opposite end a head 4l, the parts 135 to 41 in practice being rigid with one another. The left hand rod 43 as seen in Figs. 1, 2 and 6 passes loosely through the head il and has secured thereto intermediate the end of the sleeve member d@ and the inside of the head 45 a loosely fitting piston head 48. Interposed between the inside of the head 4'! and the left side as seen in Fig. 6 of the head 38 is a helical compression spring 49. The maximum possible movement of the left rod d3 with respect to the right rod "it is limited by the mechanical dimensions of the parts as shown in Fig. 6 to a distance between the end of the sleeve it shown at the right and the inside of the head 45.

From the above, it Will be seen that the spring 49 tends to draw the lower ends of the two arms 4I together and thus tends resiliently to retain the cam rollers 39 in engagement with their respectively associated cam surfaces 3l and 38. Thus under normal conditions the lamps 2 and i will be positioned as determined by the shapes of these cam surfaces and the angular position of the lamp carrier 5. These cam surfaces are so shaped in conformity with the size and shape of the lamps themselves and with the available space within the lens system, and further with the position of the point 3 (Fig. l) that at the initial position of the carrier 5, the lamp 2 will be positioned as shown in Fig. 1 with its center of illumination at the point 3. Slight errors in the positioning of this lamp may be compensated for by suitable adjustment of the nuts 33 on the pins 3i associated with this lamp. The cams are further so shaped that as the lamp carrier 5 moves in rotation, as hereinafter set forth in detail, the lamp 2 will be moved angularly from the full line position (Fig. 1) through the dotted line position and the lamp .f5 from its full and through its dotted line position, so that the lamps will be moved in a manner as not to contact with each other or with the parts of the lens system. However, if means were provided for springing each of the lamps independently toward its controlling cam 3l and 38 respectively, there might exist some factor which could cause the lamps to engage one another incident to the interchange, causing a breaking of one or both of the lamps themselves or possibly other parts of the apparatus. In order positively to prevent this, the means 42 to 49 is provided wherein the lamp supports are inter-connected together and are prevented from rotary movement in respect to the carrier 5 to such an extent that either lamp can engage the other, this movement in practice being limited by limiting the movement of the piston head 48, as hereinabove described to the space between the right end of the sleeve 4S as seen in Figure 6 and the inside of the cap or head 45. Thus there is provided a means for positively and mechanically preventing the undesired action otherwise possible. Nuts 50 threaded on the rods t3 may be loosened to permit adjustment of these rods in respect to the shackle means 2, these nuts being tightened to secure the adjustment when made. This is normally used as a set-up adjustment in conjunction with the other parts hereinabove described to determine the limits of the spring device to effect the results above described and desired.

Means are provided tending continuously to rotate the lamp carrier in a direction to move the working lamp out of its operative position and the auxiliary or spare lamp i toward its operative position. Such means in the present instance preferably includes a potential energy storing device, which from a broad point of view may be a weight or a spring. In accordance with the present invention it is preferred to use for this purpose a helical torsion spring, which is so located and protected in the device that it may be permanently lubricated. To this end there is provided a spring 5i Fig. 5) which is located inside the sleeve portion 2G forming a part of the hub of the lamp carrier 5. One end of the spring 5i is secured in a suitable springend-receiving aperture 52 formed in a part of the ange 25 of the sleeve member i3, and` thus non-rotatable with the lamp carrier. The other end of the spring iii is receive-d in a suitable bore or other spring-end-receiving aperture as shown at 5d in the outer arm il. inasmuch as the spring 5i is entirely enclosed as shown, the space surrounding this spring may be provided with a suitable lubricant of a type which will be relatively permanent during the operation of the device, this spring and its lubricant being protected by the construction shown from ingress of dirt or other contamination and also being prevented from being dried out by the heat generated from the large lamps used.

Means must now be provided for determining the initial or normal operative position of the parts at which the lamp 2 is at the position described and shown in Fig. 1 and for controlling the speed of movement of the lamp carrier during its movement to a position such that the spare lamp is at its operative position, and further for determining that position. For this general purpose, there is provided a gear train and an escapement mechanism which will now be described.

suitably secured to the inside of the lamp carrier, as by a plurality of screws 5d (Fig. 5), is a large ring gear 55, see also Figs. 4 and 9, this gear thus being rigid with the lamp carrier 5. Arranged to mesh 'with gear 55 is a pinion 56 mounted on a shaft iii which passes through the inside wall of the case E and through an instrument or mechanism panel 58 of suitable insulating material, secured` to the case 5 in spaced relation thereto and alsopasses through a pair of spaced gear housing plates iid and fifi. The panel 58 is suitably secured by screws, some of which are shown at iii (Fig. 3) to bosses, one of which is shown at 52 (Fig. 4), the bosses preferably being integral with the case t. The plates 59 and 6@ are suitably secured together in predetermined spaced reiation to one another1 and to the panel 58 by bolt and spacer means generally indicated at 63. Just inside the plate 5i! as shown, the shaft 5'. carries secured thereto as by a suitable set screw, Fig. 7, a gear Gli, which meshes with a pinion 55 rigidly carried by a shaft 56 which is journalled in the plates 59 and 69, as best seen in Fig. 8. There is thus a direct drive between the lamp carrier through gears 55 and 56 to shaft 5l, and thence thro-ugh gears 64 and @5 to the shaft ii. Also carried on the shaft $6 in a manner to be freely movable in respect thereto is a wheel t?, the periphassigoee 9 ery of which is serrated as shown for engagement with a pair of pins 68 on a wobble member 69 which is secured to a shaft 'Hi also journalled in the plates 58 and 6D.

As will later appear in detail, during the normal operation or movement of the lamp carrier from the position shown in Figs. l and 2 to its position in which the spare lamp 4 is v,at the operative position of the latter, the wheel 67 is retained rigid with the shaft 66, so .that rotation of this wheel and hence angular vmovement of the lamp carrier is controlled as to speed by the vibration of the wobble member @9. To this end, means are provided which ineffect constitute a unidirectional clutch drive device between the shaft 55 and the wheel 39, -so that upon movement of the lamp carrier 5 for Vthe automatic interchange of lamps, the wheel` 6l will be rigid lwith the shaft 66, while permitting resetting of the lamp carrier manually when a new working lamp 2 is put in position by force applied to the lamp carrier itself as hereinafter set forth and without requiring the movement of the wheel 57 or the wobble member 6B, which would have the result either of slowing upthe resetting operation or of breaking the parts, both of which resultsare undesired. For this purpose is preferred to provide a sort of free wheeling arrangement for the resetting operation, permitting rapid resetting movement of the carrier with little or no movement of the wheel 6l' and the wobble member E9. While various types of mechanisms could be provided to accomplish these results, I prefer to accomplish it by providing a pair of pawls 'Il which are pivoted on the wheel Si, at points offset from the shaft E6 and which cooperate with a ratchet 'i2 secured to shaft 5S, the pawls being suitably spring pressed toward the ratchet as shown. Thus during the automatic lampchanging movement, the shaft the ratchet if, and thezwheel El will rotate in a counter-clockwise direction as seen in Fig. without relative movement; while on the resetting movement, the ratchet 'I2 may rotate clockwise without rotating the wheel El, the pawls sliding over the teeth of the ratchet in the usual way.

This resetting movement is effected in practice by means mechanically Vengaging the lamp carrier 5. In View of the relative inaccessibility of the parts, the arm I6 of the lamp carrier is extended out in one or both directions beyond the azi-m il thereof, and has provided adjacent-to its ends perforations shown at 13 (Figs. l to 4). In practice it is contemplated that an operator may reach down through the lens vHi with a long wire having a hook on its lower end, engage the hook in the lower perforation 13 and. draw up on the wire, so as to move the lamp carrierl angularly about its center until it reaches a point at or slightly beyond that at which the working lamp 2 is at its operative position, as seen in Fig. l.

This movement may be limited by a suitable stop indicated at i4 (Fig. 2), which is formedv as a fixed abutment arranged to engage one side of the arm i5 at a point in the movement of that arm slightly beyond the position thereof shown in Figs. l and 2. The actual operating position of the parts at their operative positions shown in Figs. l and 2 is determined by other means hereinafter described.

rl"he other end of the movement of the lamp carrier is preferably accurately determined by a 10 stop means similar to stop 14 in certain respects and including a projection 'l5 through which is threaded a stop screw'TB, which may be accurately adjusted to a predetermined position andthe adjustment secured by a lock nut 71. This screw is in such a position that the upper right hand end thereof, as seen in Fig. 2, Will engage against a part of the arm I6 at the desired terminal position of that arm at which lamp 4 is at its desired operative position with its center of illumination at the point 3, Fig.4 l.

V'lhe parts n4 to T! are secured to a stop plate means which is carried rigidly by the case 6 and projects through a central opening in the cam 31 formed for this purpose.

Means are provided for supplying current to each lamp when `it is in operative position. For this purpose there is provided on the panel 58 adjacent to the bottom thereof, as seen in Figs. 3 and 9, a pair. of binding posts 18 and 19, which arearranged to be connected to suitable source of power as generally indicated in Fig. 3. In the event that direct current is used, the binding post 1B is indicated as the Vpositive terminal, and 19, the negative terminal. The apparatus is also arranged, as hereinafter more particularly set forth, for use with alternating current and further is arranged for use with lamps having different watta'ges. As shown, the positive terminal I8 is connected through lines and 8| with lamps! and 4 respectively. The other lines to these lamps, i. e., to the sockets 29 in which these lamps are held, being shown at 82 and 83 respectively and being connected to fixed contacts 84 and-85 respectively of a pair of cam operated switches. The movable contacts of these switches shown at 86 and 87 respectively Yare carried by spring strips of good conducting material shown at B8 and 89 respectively, which have associated therewith spring members 9S and 9 I which are respectively arranged to be engaged alternately by a suitable cam indicatedat 92. The lower ends of the members' and' 89 are suitably secured in bracket members 93 and 94 which are independently carried by the vpanel 58, this panel being o fl insulatingmaterial such as Bakelite The switch contacts and 8'! are connected toone another as indicated-diagrammatically in Fig.` 9 by the lines 95V and 9S, this connection in practice being between the bracket members 93 .and 94 by va strip as indicated at 91, Fig. 3. This common connection is then connected through a line including a flexible portion as indicatedat 98, Fig, 3, and a'correspondingly numbered line in Fig.y 9 selectively to either one of a pair of binding posts 99 and ft, the connection as actually shown in the drawings being to the binding post l. The purpose of this ris to vcompensate for different size lamps as to rated capacity, an indication of this rating being given in Fig. Y3, wherein the binding post 99 is designated to be for 500 or4 750 watts and binding postl for 1,000 or 1,500 watts. The purpose of this conipensation is not concerned with the operation of the relay alone, but is to prevent an abnormal voltage drop across the relay winding, coil 10|, which wouldresult in a lowered Voltage at the lamp and a reduction in light output. Binding posts 99 and |59 are connected by short leads to'diferent points on a magnet coil It! substantially as shown, the other end of this magnet coil being connected by a line' ft2 to a binding 'post H33 which in turn is connected by a leadf 'i104 to binding post-79. The lines' 80,"82, 8! and" 83 are of heavy butilexible wire so as to permitf the movement of the carrier 5, while being directly connected at each end as shown. These wires preferably extend from the inside of the case t through the sleeve member i3, and are suitably insulated by enclosing each wire in a plurality of bead members of porcelain or other insulating material as shown.

r'he cam 92 is rigidly mounted upon a shaft H35 which passes through the panel 58 and the rear Awall of the case B and has secured rigidly theren is rigid with the rotary lamp carrier, these pins y projecting to the left therefrom as seen in Fig. 4, i. e., toward the case so as to engage the outer 'portion of the lever arm |06. This lever arm is normally held in a given position by friction, so that no spring or other means is usually provided tending to turn it in either direction.

In the position of the parts shown in the diagrammatic Fig. 9 and also shown in Fig. 3, the lever arm Hit is substantially vertical, at which position the cam 92 is in engagement with the spring member Sic causing it to move the member 88 to the left to close contact members Bt and S6. This isthe condition of the parts during the time in which the principal lamp 2 is lighted. If this lamp should fail for any reason and the lamp carrier be rotated so as to bring the lamp i into operative position, the nal portion of the rotative movement of the gear 55 would cause one of these pins, say the pin lill', Fig. 9, to engage the left side of the lever it@ as seen in that gure, so as to rotate the shaft iil through about 90 and so as to move the cam 92 clockwise, as seen in Fig. 9, to open the circuit through the lamp 2 by separating the contacts dit and 8% and to close the circuit through the lamp by causing the engagement of contacts '85 and 8l.

It will now be seen that the circuit through either of these lamps may be traced as follows, from the positive terminal is through the lines Sil or 3 i, the socket and lamp in operative position, thence to the switches through the lines 82 or t3 and the switches Sli-8d or 85-31, thence by the lines 95-96 or the connector 971 and the line 98 to the coil ll, thence through the lines 02 and liifi to the negative terminal 19. It will be seen from the above that the magnet coil lili will always be in series With an operating lamp, so that irrespective of whether D. C. or A. C. current is used, the armature associated with this magnet coil as hereinafter described will be attracted thereby during the period of usefulness of the operating lamp. Preferably one of the pole pieces of the relay magnet is provided with shading coils, which may be in the form of one or more copper slugs, discs or washers in or around the magnetic path so that the relay will operate on A. C. current without excessive vibration of its armature H5. In the event that a flasher device is used, the flasher may be interposed between the source of current and the terminals 'it or l, or both, so that no action can take place irrespective of the deenergization of the coil I0! as hereinafter set forth during intermittent periods of darkness if a flashing light is to be employed.

Provision is made, as hereinafter set forth, to release the lamp carrier 5 for the interchange of lamps if the operating lamp 2 fails during a time period in which current is being supplied to the terminal 'F3-T9. For this purpose, a second magnet coil or motor relay, generally indicated at m9, is provided, which is normally deenergized and which is connected to be energized only when series coil lili is deenergized and during a time period in which current is being supplied to the terminals H8-19. The terminal 'i8 is connected by a short line Hi] to one terminal 2t! of a selenium rectifier unit IH. lThis rectier comprises two opposed sections 202 and 2d?. having a common connection or terminal 2G63. When direct current is applied to the terminals 'iS- 79 of the lampchanger, current flows from the terminal 'i8 through the conductor llc, one section 202 of the rectier l i l, a conductor i i2 from the common terminal 2M of the rectifier to the left end as shown of the winding 25M of the motor relay H39, thence through switch contacts 2&5 of the switch operated by the series relay Mil (assuming no current is iiowing through the lamp 2 and the series relay mi because of a burnout), thence through conductors Mii and ldd to the terminal i9 and the other side of the direct current line. The other end. of the section 2% of the rectier is connected to the right hand terminal H4 as shown of the winding 2234i by a conductor H3. No current flows through the section ZES of the rectier i i i during this period as its polarity is opposite to the polarity of section E92 and also opposite to the polarity of the line current. Energiaation of the winding Zilli results in the attraction of the armature l il of the motor relay It, thereby permitting rotation of the spring driven lamp carrier as hereinafter set forth. When the spare lamp 4 approaches its operating position, the contacts Si and 35 of the cam operated switch close and current now commences to flow through the conductors 8i and 83, the former spare lamp Il, switch contacts and 3l, the flexible lead Qt, and the winding of the series relay lill, and through the conductors H12 and Mill to terminal 19. Energization of the series relay iti causes the opening of its contacts 205, whereupon current ceases to flow through the section 202 of the rectier. Upon the opening of these contacts, the magnetic field of the motor magnet m9 (winding 2M) collapses, causing the production of a counter-E. M. F. in the winding 23d; and as this momentary voltage is of opposite polarity to that of the normal line current, it is dissipated through the section 23 of the rectifier iii, rather than across the now opening contacts 2235 of the series relay, thereby greatly reducing the tendency for an arc to form at that point.

When alternating current is applied to the terminals i8 and 'i9 of the lampchanger (and a lamp il is in the process of being carried into focal position), the positive alternations of the current pass through the section 2E? of the selenium rectifier and the winding 2431i of the motor relay in the circuit as previously described for D. C. operation. This results in the flow of a pulsating direct current in the relay winding 20d. At the end of each pulsation of current, i. e., during each negative alternation (60 times a second if 60-cycle alternating current is used), the eld of the motor magnet tends to collapse and cause a counter-E. M. F. to be developed in its winding 2M, which tends to oppose to some extent the normal flow of current through that winding. However, through the medium of s'ection 203 of the Vrectii-ler this counter-E. M. F. is dissipated and results in a greater flow of current through the winding 204 of the motor relay and a stronger attraction of its armature I than would otherwise take place. Furthermore, upon the opening of the contacts 205, effected by the energization of the series relay IOI and the movement of its armature H5 to the full line position shown in the drawings, this section 203 of the rectier also performs its function of preventing the formation of an arc at the contacts 205. The armature |I5 of the relay |0| is connected to the body portion of this relay by a at spring 20B, which serves not only as a flexible hinge, but also as a spring tending to move the armature ||5 to the left as seen in Figs. 3 and 9 to close the contacts 205.

The movable armature of the motor relay is in eiiect pivoted to the left hand end support for the coil as seen in Fig. 9 in any suitable manner as by providing pins rigid with the coil support passing through holes in the armature with a sloppy fit. A suitable tension spring I I8 is provided, tending to hold the armature in its upper position, except when the coil is energized. The armature Ill has rigidly secured to its upper portion a U-shaped bracket member I9 carrying a roller |20 which is arranged when the armature is at its upper position as shown, the coil |09 being then deenergized, to be in line with a part carried by the mechanical train which moves with the lamp carrier. In this case, this part comprises a radially extending pin |2| eX- tending from a hub of the gear t4. When the coil its is energized, the armature I|`| thereof is moved downwardly against the tension of the spring H8, thus moving the roller |20 out of the path of the pin |2i, this movement being substantially frictionless due to the provision of a roller as at |20 instead of a solid or non-rotatable abutment.

The series relay, comprising the magnet coil Ii and the armature I I5, is of the low reactance, quick acting type, whereas the motor relay |09, comprising the winding 204 and the armature lll, is of the high reactance, slow acting type.` Because of this fact, and the momentary heavy inrush of current due to the low resistance of the cold lamp lament, the contacts 205 carried by the series relai" lill, between the armature II5 and the terminal |241, are operated very rapidly when the relay coil I0| is energized; and because of the high reactance and inertia of themotor relay, |09, no appreciable current flows through these contacts, nor does the motor relay tend to attract the armature i even though the current to the lampchanger is periodically interrupted by means of a flasher mechanism, which may cause frequent but momentary closure of the series relay contacts 205.

Considering now the operation of the device as a whole and starting with the operation of resetting the lamp carrier after a good bulb has been inserted for use as the operating lamp 2, force is applied manually to the lamp carrier 5 to move it to the position shown in Figs. 1 to 3. This force serves to increase the potential energy stored in the spring 5I and the movement resulting from this force being continued until the lamp carrier arm I6 engages the stop 'I4 at a point somewhat beyond the desired point. Assuming at this time that current is being supplied to the binding posts '|8'|9, when the carrier is moved to this terminal position, the switch cam 02 will be positioned by the pin |08 in the position shown in Fig. 9, so as to engage switch contacts 84-85. At this time the lamp 2 will be lighted by a current flowing therethrough and through coil |0| in series therewith. When the mechanical force on the lamp carrier 5 is released, the spring 5| will move the lamp carrier until the pin |2| engages the roller |20, the motor relay |09 being at this time deenergized due to the fact that the series relay coil |0I is energized to open the switch controlled by its armature II5. This determines the normal operative position of the parts, i. e., the position at which the pin 52| will engage against roller |20.

If now the operating lamp 2 burns out, the relay itl is deenergized, permitting the closing of the switch controlled by its armature I5 and continuously energizing the relay |09 until relay lill is again energized. This, however, cannot happen until the lamp carrier has completed its movement, when upon the nal portion of the lamp carrier movement, the pin |53?, Fig. 9, will engage the lever |05 to move the cam 92 to a position to connect contacts 85 and 3l. Meanwhile, the relay |09 is continuously energized so as continuously to attract its armature il and hold it in the lower position, at which the roller i20 is out of the path of the :pin IZI. In a practical embodiment of the invention, the gear (i4 with which the pin |2i is associated makes about three revolutions during the lamp carrier movement, that movement as to the carrier 5 being substantially less than The terminal position of the parts resulting from this movement however is not controlled by the means within the case 6, but rather by the set screw it, Fig. 2, which is in a position to engage a part moving with the lamp carrier, i. e., the arm l thereof. This position is accurately adjusted and set by the set screw l5 and the adjustment secured by the lock nut l?. At this time, the carrier will have turned to such a point that cam 02 will connect contacts 85 and 87 which completes a circuit in series through the lamp ll and the coil I0! and opens contacts 84 and 3S. Thus even if a portion of the filament of the lamp 2 formerly in position were by some vibration or otherwise to contact again so as to make a short circuit within the lamp, this action would have no harmful effect as the circuit through this lamp is now broken at the contacts te and 86. The spare lam-p t is now in its operative position and acircuit is completed therethrough so that the apparatus will operate until such time as the spare lamp also burns out.

ln order that an operator or maintenance man, possibly at some distance from the light system itself, may be apprised of the fact that the operating lamp 2 has burned out, so as to be able to take the necessary steps to replace it, means are provided, arranged to be associated with any suitable alarm system. F'or this purpose, the shaft |55 carrying the cam S2 is also provided with an eccentric or cam 22, arranged to be associated with a plunger |23 of a conventional type of microswitch |24. This switch has leads |25 and Hit connected to binding posts I 2l and i23 which may be suitably connected to any desired type of alarm system (not shown). It is assumed that the alarm system will include any suitable source of E. M. and any suitable type or types of alarm means such as a light, bell, or otherwise.

Turning now to the form of the invention shown in Figs. l0 and ll, there is illustrated in. part a lamp changing apparatus arranged to be applied to a type of structure as particularly shown in' my prior Patent No. 2,289,315 granted July 7, 1942. The primary difference, however, between the present arrangement and the patented structure is that in the present arrangement the lamp carrier is intended for rotation only through a limited arc ci not over about 180 and in addition the lamps are not maintained Vertical, yas in the patented disclosure referred to, but are progressively tilted While maintaining them in the same plane. So, for example, a lamp |29 in moving from its operative position shown in full lines in Fig. 11 will move through an intermediate positon shown in dotted lines at I3@ to a nal inoperative position shown in dot-anddash lines at |32, the longitudinal axis of this lamp being progressively changed from the vertical at the operative position of the lamp to the position shown at |3|. At the same time the other lamp shown at |32 in full lines in this figure moves through an intermediate position in dotted lines at |33 to a position coincident with that shown for the lamp |29. The angle of the longitudinal axis of the lamp |82 with respect to the vertical progressively moves toward Zero .as the carrier is moved in the lamp interchange operation. This is necessary, for as seen best in Fig. 10, the lamps |29 and |32 are so large that they could not be held vertically at their inoperative or lower positions as shown in l0, as they would engage the holder portion of the other lamp. By the provision of this special angular movement while maintaining the lamps generaliy vertical, I am enabled to use a carrier which is substantially the same as that shown in prior patent and thus minimize the number of diiferent types of structures which need be manufactured for accommodating diiferent sized installations.

Referring now more particularly to the drawings, the stationary support for the lampehanging device is shown at |3113, this structure corresponding to the structure iii of my prior patent. Rigidly mounted in this support is a stationary stud |35 about which a lamp carrier generally indicated at |3|i may rotate, the axis of the stud |35 being horizontal, as shown.

The carrier |36 may be rotated by any suitable means (not shown), for example, means such as are shown in my prior patent, but not here shown in detail, such means being in general indicated by a ring gear E37 secured to the carrier and meshing with a pinion |38, which may be suitably connected to a driving mechanism. Il? then any well-known type of free wheeling device be arranged in conjunction with the driving mechanism, so as to permit manual resetting of the carrier |3|5` after it has been moved through an angle .of 180, such as a friction clutch or a pawl and ratchet device as shown at M -"i2, Fig. 7, the .carrier driving means of my prior patent aforesaid may be adapted for this purpose. On the lother hand, any suitable spring-actuated means, such as that particularly described in respect to the preceding figures and including a torsion spring as shown at 5|, Fig. 5, located at any convenient part of the device, or a weight-actuated mechanism as generally referred to hereinabove, may be employed in conjunction with an escapement means as particularly described above. It will be understood that as to this form of the invention, the specific type of actuating means for the carrier is relatively immaterial.

Means are provided for stopping the rotative movement of the carrier at each of its terminal positions, in this case at points 180 apart. For this purpose the carrier |36 is provided with a pair of pins 'H9-Mil diametrically disposed in respect to the carrier axis and arranged to engage the opposite sides of a ilapper lever |42, which is pivoted as shown at |52, Fig. 1l, and is adapted to be engaged by the pins. The lever Eli is freely movable about its pivot. Movement of this lever is limited, however, by a pair oi adjustable stop screws m3 and Mii, threaded through suitable lugs carried by the support |34 and secured in adjusted position by lock nut means in a conventional manner. By the adjustment of these screws Hit and |44, the limits of the carrier movement may be accurately determined, so as to insure the correct positioning of each lamp in the exact focus of any lens system with which the device is associated.

In the form of the invention shown the lamp carrier |36 carries rigidly secured therein adjacent to its outer ends a pair of horizontally disposed studs it which are secured to the carrier as by nuts MS. livoted about each of these studs is a lamp carrier casting itl. The casting ill has secured thereto a suitable lamp socket Ei and an insulating block its carrying the contacts for 'transmission of electric power to the lamp. Inasmuch as these parts it to |49 are the same for both lamps, the same reference characters have been used for both.

Means are provided for rotating the castings ld? about the horizontal axes of the studs incident to and proportional with the rotation of the carrier |36 about its axis stud |35. In general, means similar to either of the arrangements shown in my prior patent could be used for this purpose, that is, either a train of gears as particularly shown in Figs. l0 and l1 of the accompanying drawings, or sprocket and chain means as shown, for example, in Figs. 1, 2 and 4 of my prior patent above referred to. The essential characteristic is, that in accordance with the present invention, a non-parallel linkage is provided, that s, one in which the longitudinal axis oi each lamp is not maintained vertical, but is progressively varied from the vertical as the lamp moves from its operative position and vice versa, the lamp in its operative position preferably being vertical, as shown.

In effecting this result in accordance with the present disclosure, there are provided one or more stationary gears |56, two of which are shown in the accompanying drawings, although but one need necessarily be used. These gears are splined to the stud it, so as not to rotate with the carrier |36. Meshing with the gears |50 are a pair of idler gears |5| freely rotatable on axes carried lby the carrier |36. Meshing with the idler gears il are gears i52, which are respectively rigid with and carried by the castings |41, being secured thereto as shown by one or more screws |53, Fig. 10. lf then the gears |52 are provided with a greater number of teeth than the gears |50, the results shown diagrammatically in Fig. 1l will ensue. The angle of the lamps to the vertical at their inoperative positions shown in full lines for the lamp |32, Fig. 11, and in dotand-dash lines at |3| for the lamp |29, will depend upon the ratio or ratios of the number oi teeth of the gears |52 in respect to the gear or gears tt, any desired ratio or ratios being used within the purview of the present invention in order that there will be no interference of parts incident to any possible movement of the lamp carrier |36.

It will be noted from the above that the lamps are always maintained in a single vertical plane aangereibythe movement of the carrier 136, but that-they are moved in respect to the carrier in sucha manner that there will be a substantial difference be tween the angle of the longitudinal axis of each lamp in this plane at its operative positionoinV respect to the angle of the axis of such lamp at its inoperative position. In this respect a some what similar result is attained to that disclosedY in the form of the invention shown in Figs.V 1-9 in that there the angle of each lamp with respect to the carrier and with respect-to the vertical is controlled by a cam surface, while as shownlin Figs. l and 11 this angle is controlled-v bythe ratio of the number of teeth of a pair of gears in a gear train.

The means shown in Figs; and 1l for coni-- ducting current to the several lamps. mayf be?l identical with that fully described in my prior.

Patent No. 2,289,315 above referred` to and. is,A

therefore, not particularly described herein, such'` means being in general indicated. byV thelrefer` On the. other,` hand,z it.mayfv ence character |54. be desired to conduct current. to the lamps by permanent connections similar to theVv arrangement disclosed in Figs. l-9 and in the accompanying description hereinabove. SuchA an.- ar.- rangement is to be considered withinthe purview of this invention.

While I have shown anddescribed but atfew of the possible embodiments. of the. invention, vari!- ous additional variants have beensuggestedsand:

others will present themselves to thoseskilledin..Y

the art. I do not wish tobe limited,.therefore,z except by the scope of the appended claims; which are to be construed validly,.as broadly asy the state of the prior art permits.

What is claimed is:

1. Lampchanging apparatus for use withaV Fresnel lens of minimum size permittinglamp. interchange and having a ,focal point,..compris;-` ing a stationary support,v arotary lamp carrier.` mounted on said support for movement in re spect thereto about a substantially horizontall.

axis, means limiting the movementV ofsaidlamp:

carrier about its axis to less than 180, a-.pair of. 45;

electric lamps mounted on said carrier at. sub1 stantially diametrically opposite pointsand-forr movement in respect thereto about horizontal axes, each of said lamps having an axis of` sym'- metry and having a dimension along said; axisi of symmetry greater than the distance between.,

said diametrically opposite points, an intere-` changeable stationary cam mounted on'said sup-- port adjacent to said carrier having; azcamsur= face respective to each of saidY lamps, camY fol-l lower means respectively associated with; said;A cam surfaces and arranged to operate inV reevr sponse to movement of said'carrier torotate'said: lamps about said horizontal axes'in respect to. said carrier, said cam surfaces beingconstructed and arranged in conformity with theV size and.'r

shape of said lamps and the dmensions'ofthe;

associated Fresnel lens so as to control the moves ment of one of said lamps from an operative po..-

sition wherein its center of illuminationis atrthezfocal point of said lens to an inoperative position and to control the movement of the other ofsaid lamps from its inoperativeposition to an operative position in which its center of illumina-- tion is at the focal point of said lens bymoving;

said lamps through paths. such'V that they will: pass one another in spaced relation and will be; maintained out of contact withany--partl offsaid.;`

lens.

2..Lampchanging apparatusA inv accordance withl claim 1, wherein said' cam follower meansA are mechanically interconnected, so as positively to prevent saidV lampsA contacting one another during movement ofY sa-id carrier and said lamps as aforesaidl 3. Lampchan'gingl apparatus, comprisingy a' sta-- tionary support, a rotary lamp carrier mounted on said support for movement in respect thereto about a4 predetermined axis; ay plurality of elecf tric lampsY mounted" onu said carrier for' move-Y ment in respect thereto about axes parallel to`v the first-named axis, means'formovingV saidcar-Y rieriin respect to-said support, a stationaryV cam carried bysaid support adjacent to said carrier and having'a peripheral cam-surface respectivelyI associated witheach'of said'lamps, a cam"fol'- lower respectively associated with' each of said lamps andfsaid camsurface's forcontrollingitheangular position thereof in respectto said'car'f rier,v means including'a spring for urging both` said followers against' theirH respective surfaces" of said-"cam and: for' mechanically interconnecting'sai'd followersthroughsaidspring and means-y in such` mechanical interconnection" means' in-`V lcluding a mechanical/stop for positivelyprevent'- ing suchangular movementof either'ofA` said lamps as could'causesaid lamps to touch one* another-during themovement of said lampsinlcident' to4 the movement of said;` carrier.'

4. Lam'pchanging apparahis; comprising a stationary support, a' rotarydamp carrieifstructureV Vvand -means `including -aunidirect-ion'al clutchhdrive device-interposedv in ysaid-mechanical` tra-inandeifectivesupon'- manual resetting-ofsaidcarrier to restore saidfpotential energy@ storingy means to its initial physical condition byiorce'appliedto said .carrier for permittinga rapidresetting of-VV said carrier without requiring. movement -of.said escapement means incidentA thereto.

5. Lampchangingapparatus iii-accordance withL claim 4,-Ywherein` said uni-directional-clutch drive device-isa ratchet and-paw-l. mechanism.

6. Lampchanging apparatuslin-aecordance w-ithclaim 4,- wherein -saidr potential energy storing; means -is a-helical torsion spring.-

7. Lampchangfing apparatus in accordancewitlri-A vrclaim 4, wherein saidpotential energy storingI means is--a spring, and-comprising: infaddition:` meansforminga chamber'for containing saidispringfand also for conta-ininga lubricant forthe4m spring substantially permanently sealed inv` saidi chamber, wherebyto vprevent. the spring from-` being fouled byfdirt andtherlubricant from-being dried -out bythe heat Vgeneratedby said lamps-J 8;* Lampchanging'apparatus in-accordance with claim` 4, comprising inl addition a-'hollowv annularI drum forming al part offsaid lamp`carrier=structure andrforminglaninternal chamber for 're'ceiv`-vv ing a helical torsion-spring whichis=said poten tial energyk storing,v means,..one.end.ofl said springl being secured to.y saidrlamplcaririer structure andi the other lend Atola 0part? rigidswith saidf supporti-r said chamber also providing an enclosure for containing lubricant for the substantially permanent lubrication of said spring during its operation.

9. Lampchanging apparatus, comprising a stationary support; a rotary lamp carrier structure mounted on said support for movement in respect thereto about a predetermined axis; a plurality of electric lamps arranged to be brought, by the movement of said carrier structure, to position such that their centers of illumination are successively at a predetermined point; means for rotating said carrier in respect to said support, including potential energy storing means constantly urging said carrier to rotate in a predetermined direction in respect to said support, a mechanical train and an escapement means for limiting the rate of rotation of said carrier as driven by said potential energy storing means, and means including a unidirectional clutch drive device interposed in said mechanical train and effective upon manual resetting of said carrier to restore said potential energy storing means to its initial physical condition by force applied to K said carrier for permitting a rapid resetting of said carrier without requiring movement of said escapement means incident thereto; means for stoppmg the rotary movement of said carrier with one of said lamps in its operative position with its center of illumination at said predetermined point; and means subject to the burning out of the lamp in its operative position for automatically releasing said carrier for movement, by force derived from said potential energy storing means, to a position such that a second lamp is at its operative position with its center of illumination at said predetermined point.

10. Lampchanging apparatus in accordance with claim 9, wherein said stopping means comprises a rigid abutment means and a roller, one of which is carried by a member movable with said carrier and the other of which is carried by said releasing means, said roller operating to minimize friction incident to the releasing operation.

1l. Lampchanging apparatus in accordance with claim 9, wherein the last two named means including the stopping means and the releasing means comprise a pin projecting laterally from a rotating element of said mechanical train, a magnet having a movable armature, a roller carried by said armature in position when said magnet is deenergized to be interposed in the path of said pin so as accurately to predetermine the initial position of said lampv carrier structure with one lamp at its operative position with its center of illumination of said predetermined point, and an electric circuit including a magnet operated switch of which the magnet is in series with an operating lamp at its operative position and arranged upon cessation of electric current iiow through such lamp to complete a circuit through the rst named magnet so as to withdraw said roller fromv the path of said pin and thereby to permit movement of said lamp carrier under the influence of said potential energy storing means to move a second lamp to its operative position.

12. Lampchanging apparatus, comprising a thereto about horizontal axes arranged diamet-v rcally opposite one another on said carrier and at uniform distances from the axis of rotationthereof,y a stationary cam, removably and interchangeably secured to said support and having peripheral cam surfaces on each side arranged respectively to control the positions of said lamps in respect to said carrier, lever arms and cam followers associated with each of said lamps for cooperation with the respective cam surfaces of said cam, mechanical interconnecting means including a spring interposed between said lever arms and cam followers for urging said cam followers against the respective cam surfaces and including means for mechanically limiting the angular movements of said lamps toward one another so as positively to prevent said lamps touching one another during movement of said carrier, said cam surfaces and the movement of said carrier being conjointly so constructed and arranged in accordance with the shape and size of said lamps that at one terminal position of said carrier one of said lamps is at its operative position with its center of illumination at substantially a predetermined point, while at the other terminal position of said carrier, the other of said lamps is at its operative position with its center of illumination at said point, while said lamps are moved to and from their operative positions in paths close together so as to enable the apparatus to be employed with a Fresnel lens of minimum size permitting lamp interchange by the mechanical movement of one lamp past the other; means for rotating said carrier in respect to said support including a helical torsion spring concentric with said carrier and disposed centrally thereof, said spring tending at all times to rotate said carrier, a mechanical train and an escapement means for limiting the rate of rotation of said carrier by said spring, and means including a pawl and ratchet device interposed in said mechanical train to permit the resetting of said carrier in its initial position against the action of said spring without requiring movement of said escapement means incident thereto; stop means for predetermining the initial position of said carrier comprising a magnet armature having a roller thereon interposed in the path of movement of a part moving with said carrier and included in said mechanical train, and an elec-tric circuit including an electro-magnet switch, the magnet of which is in series with a lamp in its operative position and operative upon the cessatation of currrent flow through such lamp for energizing the rst named magnet to withdraw said roller from the path of movement of movable parts of said mechanical train, so as to permit of the movement of said carrier to bring the second lamp to its operative position while withdrawing the first lamp therefrom, and switch means actuated by movement of said carrier for cutting off electric current ow through the first lamp removed from its operative position and connecting the second lamp positioned at its operative position in the circuit.

13. Lampchanging apparatus for use with a substantially cylindrical Fresnel lens having a focal point located substantially on the axis of said lens, comprising a stationary support, a rotary lamp carrier mounted on said support for movement in respect thereto about an axis perpendicular to the axis of said lens, two electric incandescent lamps mounted on said carrier, each of said lamps having a longitudinal axis of symmetry, at one point on which is a center of illumination of the lamp, mounting means for each said lamp pivoted to said carrier for move- 21 ment in respect thereto about an axis parallel to the axis of said carrier in respect to said support, the mounting of said lamps being such that during movement of said carrier the axis of each of said lamps is maintained in a plane including the axis of said lens, a stationary cam mounted rigid with said support for each lamp respectively, cam follower means for each said cam, mounted on said carrier and connected to said lamps respectively for controlling the relative positions of each of said lamps in respect to said carrier during the movement of said carrier, and means for rotating said carrier from one predetermined angular position in respect to said support to another such position, said cams being so shaped and designed that said lamps will just pass without contact with one another or with said lens during movement of said carrier to move one lamp from'an operative position with its center of illumination at lthe focal point of said lens to an inoperative" position and to move the other of said lamps from an inoperative position to an operative position with its center of illumi- 22 nation at the focal point of said lens, each of said lamps at its operative position having its longitudinl axis of symmetry at a substantial angle to the aXis of said lens, whereby a lens of minimum size permitting lamp interchange may be used with said lampchanging apparatus.

JOHN R. MACKAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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