Abstract:
An incandescent lamp socket comprises a housing for receiving the base portion of an incandescent lamp and switch means for selectively connecting the lamp&#39;s contacts to a source of electrical energy. Such switch means comprises a rotatably mounted cylindrical sleeve which surrounds the socket housing, and means responsive to rotational movement of the sleeve relative to the housing for selectively connecting the lamp contacts to the energy source. Preferably, such connecting means comprises a planetary ring gear disposed along the interior wall of the sleeve, a cooperating pinion gear mounted for rotational movement on the socket housing, cam means rigidly coupled to the pinion gear and rotatable therewith, and electrically energized cam follower means, movable in response to the cam means to selectively energize certain socket electrodes which are connected to the contacts of a lamp supported by the socket housing. According to another embodiment, the pinion gear is used to control the output of a conventional potentiometer which, in turn, controls lamp power.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to energizable lamp sockets for use in household lighting fixtures (e.g. table, floor and wall-mounted lamps for selectively applying electrical power to an incandescent electric lamp. 
     Most conventional lamp sockets have push-button, twist-type or pull chain activated switches which are, at times, difficult to locate, especially so when hidden by a lamp shade and thereby locatable only by touch. It would be desirably to provide a lamp socket switch which, even though hidden from sight, can be readily grasped and operated by the user without regard to the user&#39;s position relative to the lamp socket switch. 
     SUMMARY OF THE INVENTION 
     According to the invention, there is provided a selectively energizable lamp socket in which electrical energy is selectively applied to the electrical contacts of a received incandescent lamp by switch means comprising a rotatably mounted cylindrical sleeve which is concentrically arranged relative to the lamp socket housing. Means, positioned within the sleeve and responsive to rotational movement of the sleeve, are provided for selectively connecting and disconnecting the lamp contacts and a source of electricity. In accordance with a preferred embodiment, such connecting means comprises rotatably mounted cam means which rotates in response to manual rotation of the sleeve, and electrically energizable cam follower means which moves, in response to cam means rotation, between a first position in which it engages the lamp contacts and applies electrical energy thereto, and a second position in which it is spaced from such contacts. Preferably, the cam means is mounted for rotation by a pinion gear which is rotatably mounted on the socket housing and positioned to be rotatably driven by a planetary ring gear mounted within the manually rotatable sleeve. This basic arrangement and combination of parts is useful in applying energy to lamps with single or multiple (e.g. three-way) filaments. In accordance with another embodiment, the combination of the planetary ring gear and the pinion gear is used to control the position of the resistance-varying shaft of a potentiometer which, in turn, controls the voltage applied to a single filament lamp. 
     The invention will be better understood from the ensuing detailed description of preferred embodiments, reference being made to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of an energizable lamp socket embodying the present invention; 
     FIG. 2 is an exploded view of the lamp socket shown in FIG. 1; 
     FIG. 3 is an enlarged exploded view of a portion of the apparatus shown in FIG. 2; 
     FIGS. 4B and 4A are top elevations of a portion of the FIG. 2 apparatus showing the electrode structure in &#34;on&#34; and &#34;off&#34; positions, respectively; 
     FIG. 5 is a fragmentary view of a portion of a three-way incandescent lamp base; 
     FIG. 6 is an exploded view of a portion of a three-way lamp socket according to another preferred embodiment; 
     FIGS. 7A and 7B, and 8A-8D are top elevations of a portion of the FIG. 6 apparatus showing the relative positions of elements for various operating and non-operating conditions; and 
     FIG. 9 illustrates still another embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to the drawings, FIG. 1 illustrates a conventional single filament incandescent lamp L supported by an electrically-energizable socket S embodying a preferred form of the present invention. As will be explained in more detail below, electric energy is selectively applied to the lamp&#39;s filament by rotating a generally cylindrically shaped sleeve 10 about its longitudinal axis A. Preferably, the outer surface of sleeve 10 is shaped and contoured, such as by grooves 12 or flats (not shown), to be readily gripped and rotated by hand. By virtue of the mechanism within the sleeve, lamp energization and de-energization is independent of the direction of sleeve rotation. 
     Referring to the exploded view of FIG. 2, socket S comprises a non-conductive (e.g. plastic) housing 20 comprising upper and lower platforms 22, 24, respectively, and a plurality of interconnecting walls 26. Platform 22 supports a cylindrically-shaped electrode 30, the wall of which is adapted to receive the threaded base contact of lamp L. Electrode 30 is electrically connected to a conductive member 32 which is supported by one of the housing walls 26. Conductive member 32 supports a contact screw 32a which is adapted to be connected to one of the two leads of a standard electric power cord. 
     Referring additionally to FIG. 3, the upper surface of platform 22 also supports a second electrode 40 which is spaced from and centrally disposed relative to the cylindrical electrode 30. Electrode 40 has a flat portion 42 which is fastened to the upper surface of platform 22 by a screw 43, an angularly disposed portion 44 which engages the tip contact of a lamp received by the threaded electrode 30, and a depending tab 46 which protrudes through platform 22 into the region separating platforms 22 and 24. It is tab 46 which is selectively connected to a source of electrical energy (by the mechanism next described) to complete the lamp circuit. 
     As shown in FIGS. 3 and 4A and 4B, tab 46 is positioned between a pair of electrically conductive cam follower members 50 which move toward and away from each other under the influence of a rotating cam member 52. The cam follower members are always &#34;hot&#34;, that is , electrically energized due to their physical contact with an electrode 54, the latter being directly connected to the other lead of the aforementioned power cord by screw contact 55. Electrode 54 is connected to the lower platform 24 of housing 20 by screws 57. Cam follower members 50 protrude through an aperture 58 formed in electrode 54, and good electrical contact is assured by a compression spring 60 which urges the ends 50a of members 50 into engagement with the lateral edges of aperture 58. Spring 60 also serves to cam follower ends 50b into intimate contact with cam member 52. Locating pins 62 mounted on each of the cam follower ends 50a serve to keep the spring in its proper position between ends 50a. 
     Each of the cam follower members 50 has an elbow-shaped end 50b which is urged into engagement with, and thereby accurately follows the movement of, cam member 52. The cam member is supported by and rotates with a pinion gear 66 which is rotatably supported by an axle 68 which is rotatably supported by and extends between platforms 22 and 24. Pinion gear 66 is positioned so that its teeth are engaged and driven by teeth of a planetary ring gear 70 which is supported by, and is preferably integral with, the interior wall of sleeve 10. The operation of the socket can be best understood with reference to FIGS. 4A and 4B. As pinion gear 66 rotates in response to rotation of sleeve 10 and its internal planetary ring gear 70, cam 52 rotates between the two positions shown. In FIG. 4A, the position of cam 52 serves to space the electrically energized cam follower members 50 apart from tab 46; hence, in this position, no power is applied to the lamp&#39;s tip contact 102, and the lamp is &#34;off&#34;. In FIG. 4B, the cam member is turned 90 degrees, in which case the cam followers are allowed to move toward each other (under the influence of spring 60) and make electrical contact with the tab portion 46 of electrode 40, thereby completing the lamp circuit and turning the lamp &#34;on&#34;. To assure good electrical contact between tab 46 and members 50, breaker points 69 may be provided, as shown. 
     From the foregoing description, it will be apparent that the direction of rotation of sleeve 10 is not critical to the operation of the device. If the lamp is already energized when the sleeve is initially rotated, as would be the case shown in FIG. 4B, rotation of the sleeve 10 in either direction will cause a break in the electrical circuit. Obviously, the converse is true. Also advantageous is that any slight welding or fusing between the contacts can be easily broken by the relatively strong force provided by the rotating cam member. Also, a strong detent &#34;feel&#34; is provide by the combined effect of the compression spring and the shape of the cam member. Note, once the cam member rotates to about its 45 degree position, half way between the positions shown in the drawings, the cam followers will snap into the intended next position. 
     Regarding the sleeve member 10, it is preferably made of a plastic material. Its internal planetary ring gear 70 may be formed separately from the sleeve and, for example, press fit into the sleeve&#39;s interior surface. Preferably, however, the ring gear is integrally formed with the sleeve&#39;s inner surface, such as by standard injection molding techniques. 
     Referring again to FIG. 2, housing 20 and its associated structure are contained by a conventional two-piece, snap-together socket housing consisting of a base portion 80 and an upper portion 82. The upper portion of this socket has been modified by the addition of a transverse opening 82a which, in cooperation with the upper edge 80a of base 80 provides a slot through which a portion of the pinion gear 66 protrudes for engagement by the ring gear 70. To prevent housing 20 from rotating as sleeve 10 is rotated, platform 24 of the electrode housing 20 is provided with a key 24a which is arranged to engage a notch 84a defined by a pair of tabs 84b depending from a bearing ring 84. Ring 84 is multipurpose, providing a bearing surface for rotably supporting the bottom edge of the ring gear, providing a dust cover for the ring gear and, as already mentioned, providing a means for preventing undesired movement of housing 20. Also to be noted is that tabs 84b prevent the entire housing 20 from sagging into the socket base 80 during assembly. When assembled, the top of upper housing portion 82 extends above the top of sleeve 10. A retainer ring 85 having a plurality of cut-outs 85a which are located to engage opposed embossings 82b on upper housing portion 82 serves to lock the assembly together. 
     Referring now to FIG. 5, there is shown a fragment of the base portion of a conventional three-way incandescent lamp 100. Such a lamp has three electrical contacts, a center tip contact 102, a threaded base contact 104, and an intermediate ring contact 106. The lamp has two filaments, a 100-watt filament connected between lamp contacts 102 and 104, and a 50-watt filament connected between contacts 104 and 106. As in the case of the above-described single filament lamp, contact 104 is directly connected to one of the two leads of a power cord, and either or both of the lamp filaments are selectively energized by connecting either or both contacts 102 and 106 to an energy source. When the threaded base contact is screwed into the threaded socket electrode, such as electrode 30 in FIG. 2, center tip contact 102 engages socket electrode 110, shown in FIGS. 5 and 6, and ring contact 106 engages a third socket electrode 112. The mechanism for selectively connecting electrodes 110 and 112 to a source of electrical energy in response to rotational movement of sleeve 10 is described below. 
     Referring to FIG. 6, the apparatus shown is supported by the same socket housing 20 as already described above with reference to FIG. 2. The horizontal portion 110a of electrode 110 is fastened to the top surface of the housing&#39;s platform 22, and its depending tab 110b extends downwardly, through an aperture formed in platform 22, into the region between the platforms 22 and 24. There, tab 110b is selectively engaged by an electrically energized cam follower member 116 which moves toward and away from the the tab as it follows the contour of a cam member 120, described in more detail below. Electrode 112 comprises a flat flange 112a which is fastened to the bottom surface of platform 22. Extending upwardly from flange 112a is an upright portion 112b which protrudes through an aperture in platform 22 and engages the ring contact 106 of a received lamp. Extending downwardly from flange 112a, into the space separating the socket&#39;s platforms 22 and 24 is a tab 112c. As in the case of the electrode tab 46 in the above-described embodiment, tab 112c is arranged between a pair of electrically energized cam follower members 118 which move toward and away from each other, into and out of engagement with tab 112c, as they follow the contour of a second cam member 112. The cam follower members are electrically energized by virtue of their contact with an electrode 130 having a shape similar to electrode 54 in FIG. 3. The cam followers extend through an aperture 132 formed in electrode 130, and springs 136 serve to urge the cam followers into intimate contact with the lateral edges of the electrode aperture. Note, the spring associated with the upper cam follower 116 is positioned by a locating pin on member 116 and by a pin 139 borne by electrode 130. Electrode 130 is directly connected to an energy source by contact screw 138, and a pair of screws 140 serve to fasten the electrode to the lower socket platform 24. 
     As best shown in FIG. 6, cam members 120 and 122 are stacked one above the other on top of a pinion gear 125. All three members share the same axis of rotation, defined by the longitudinal axis of axel 68. Cam member 122 is identical in shape to cam member 52 described above, having to lobes which are 180 degrees apart. While cam member 120 also has two lobes, it differs in shape from cams 122 and 52 in that its two lobes are only 90 degrees apart, or 270 degrees, depending on the direction of measurement. The pinion gear and its associated cam members are mounted for rotation between platforms 22 and 24 in the same manner as the above-mentioned pinion gear 66 and cam 52. Preferably, the pinion gear and cam members are integrally connected, being formed by a standard injection molding technique. Again, the pinion gear is located on housing 20 such that a several of the teeth thereof are engaged and driven by the teeth of the planetary ring gear within sleeve 10. 
     The operation of the three-way socket of this particular embodiment of the invention will be better understood by referring to FIGS. 7A and 7B, and FIG. 8A-8D. As cam member 122 rotates, the 50 watt filament is alternately turned &#34;on&#34; and &#34;off&#34; as the cam&#39;s position is changed between the two positions shown in FIGS. 7A and 7B. In FIG. 7A, cam 122 is positioned so that the electrically energized cam follower members 118 are allowed to contact tab 112c and thereby energize the ring electrode 106 and the 50 watt filament connected thereto. In FIG. 7B, cam 122 is positioned to space the cam followers sufficiently apart to prevent electrical contact between the cam members and tab 112c; as a result, no power is applied to the 50 watt filament. Thus, it is apparent that, for each full revolution of gear 122, energy is turned on and off twice, each change in state being separated by a 90 degree cam rotation. 
     Coincidentally with the rotation of cam 122 is the rotation of cam 120. When cam 120 is in the position shown in FIG. 8A, one of its two lobes serves to space cam follower 116 from electrode 110 and thereby prevent energization of the 100 watt filament. When cam 122 is also in a position to prevent energization of electrode 112, the lamp is in its &#34;off&#34; condition, as shown in FIG. 8A. After the two cams have rotated 90 degrees in a counter-clockwise direction to the positions shown in FIG. 8B, both of the cam members are positioned to allow their associated cam followers to make contact with, and thereby energize, their associated electrodes. Thus, in FIG. 8B, both lamp filaments are energized and the lamp power is 150 watts. As the cam members rotate 90 degrees further in a counter-clockwise direction, cam 120 is still in a position to allow energization of electrode 110; however, cam 122 will have rotated to a position in which it de-energizes electrode 112. This condition is depicted in FIG. 8C where only the 100 watt filament is energized. In FIG. 8D, the cam members have been rotated 90 degrees further and, as shown, cam 120 acts to de-energize electrode 116 and its associated 100 watt filament, while cam 122 allows energization of the 50 watt filament via electrode 112. 
     In FIG. 9, another embodiment of the invention is shown. Here, the combination of a ring gear 155 and pinion gear 155 are used to drive a second pinion gear 160 whose central portion is fixed to the stem 170 of a conventional potentiometer (not shown). The ring gear, of course, is arranged within a sleeve like sleeve 10 in FIG. 2. As the sleeve is manually rotated, the resistance of the potentiometer is varied, thereby varying the lamp power. Obviously, the potentiometer is connected in the power line to vary the voltage applied to the lamp-contacting electrode 40. 
     From the foregoing, it is apparent that a relatively low-cost and highly advantageous lamp socket has been provided. By merely twisting the sleeve which surrounds the lamp base, power is applied to the lamp, and the need to locate a mechanical switching mechanism is obviated. While the invention has been described with reference to certain preferred embodiments, obvious modifications will become self-evident to those skilled in the art, and such are intended to be within the spirit and scope of the invention, as defined by the accompanying claims.