GB2052178A - Lampsockets - Google Patents

Abstract

A lampsocket with an electronic dimmer control is moulded in dielectric material and has a rotatable collar mounted about its periphery for the purpose of controlling electronic lamp dimming circuitry contained within the body of the lampsocket. In a first embodiment (shown) a lever 8 extends through a slot 5 in the lampsocket body from a potentiometer 10 mounted inside the lampsocket and engages a groove 6 in the control collar 2. In a second embodiment the lampsocket is in the form of an adaptor for use in ordinary lampsockets, the control collar having a recess containing a resistor strip element which is in contact with two wiper contacts extending from holes in the adaptor body and connected to further dimmer circuitry within the body, thus utilizing a portion of the inside surface of the control collar as a means of eliminating the potentiometer from the limited space within the adaptor body. <IMAGE>

Description

SPECIFICATION Lampsocket with electronic dimmer control This invention relates to a lampsocket and more particularly to a lampsocket with an electronic dimmer control for use in controliing the amount of electric current flowing through a light bulb located in the socket.

Many different types of lampsocket are available with a variety of current controlling means i.e.

switches such as nobs, chains, buttons etc.

However, these controliing means only allow the lamp to be either on or off and they do not permit any variation in the current flowing through the bulb and hence in the amount of energy used. This causes a momentary surge of current, which can for an instant be as high as twelve times that of normal current, passing through the low resistance cold filament of the bulb when the switch is snapped on with the result that the lifetime of the bulb is considerably shortened.

Moreover, many of these different types of switch are difficult to operation, especially by handicapped people.

We have now developed a current controlling means which obviates at least some of the above problems.

According to the present invention, there is provided a lampsocket moulded in dielectric material having a rotatable collar mounted about the periphery of said socket for the purpose of controlling an electronic lamp dimming circuit contained within the body of said lampsocket.

In a first preferred embodiment, a lever extends from a potentiometer mounted inside the lampsocket body and passes through a slot of about 1200 arc in said lampsocket body to engage a groove in said control collar. Preferably the electronic lamp dimming circuit is mounted on a printed circuit board.

In a second preferred embodiment of the invention, the lampsocket is in the form of an adaptor which is provided with a screwbase or a bayonet mounting for use in ordinary lampsockets to provide a full range dimming capability.

Preferably in this construction the control collar of the adaptor socket has a moulded projection extending from the inside thereof to form part of a stop mechanism to limit rotation of said control collar about the periphery of the lampsocket, the other part of the stop mechanism being a recessed channel formed in the body of the socket in which the projection slides. Preferably the control collar has a recess containing a resistor strip element, thereby utilizing a portion of the inside surface of said control collar as a means of eliminating a potentiometer from the limited space within the lampsocket body.

Preferably the adaptor lampsocket has a two piece moulded body. On the inside of one piece there is provided a recess containing a metal conductor which makes contact with the neutral screwbase of a lamp bulb and the screwbarrel portion of the lampsocket. The other piece preferably has the recessed channel on its outside surface to receive said stop. Preferably the remaining dimmer circuitry is located between the two pieces of the lamp socket body. Forming part of said circuitry is a centre contact live terminal projecting from the base of the socket and two wiper contacts spaced preferably 1800 apart about the periphery of the body, said wiper contacts extending through holes in the lampsocket body for contact with the resistor strip mounted in the rotatable sleeve thereby forming a potentiometer.

Two embodiments of the invention are now described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a side view of a first embodiment of a lampsocket with its rotatable collar removed, Fig. 2 is a longitudinal or vertical cross section of the lampsocket of Fig. 1, Fig. 3 is a circuit diagram of the lamp dimmer circuit, Fig. 4 is an underneath view of the circuit board, and showing part of the control collar, the remainder of the lamp socket having been omitted, Fig. 5 is a top perspective view of the screw shell (looking down into the socket), Fig. 6 is a side view of a second embodiment of a lampsocket in the form of an adaptor, Fig. 7 is a side elevation of the inside of one piece of the Iampsocket body of Fig. 6 with the outer sleeve removed, Fig. 8 is a top or end view of the control collar of the lampsocket, Fig. 9 is a side elevation of the lampsocket of Fig. 6 with the control collar removed (and of the outside of a second piece of the body), and Fig. 10 is a longitudinal or vertical cross sectional view of the control collar of the lampsocket.

Referring to Fig. 1 , there is shown a lampsocket comprising a body 1 having a removable end cap 4. The body 1 has a cylindrical portion 7 on which a cylindrical control collar 2 (see Fig. 2) is rotatable and a threaded portion 9 separated by a ridge 3. A slot 5 extends around part of the circumference of the cylindrical portion of the body 1 and a lever 8 extends from a potentiometer 10 (see Fig. 2) in the centre of the body through the slot 5.

As can be seen from Fig. 2, a printed circuit board 12 is contained in a cavity 14 formed by the body 1 and the end cap 4. Attached to the circuit board is a live terminal post 16 6 and a neutral terminal post 1 8 is attached directly to a screw she!l 11 contained in the threaded portion 9 of the body 1. The potentiometer 10 is centraily mounted on the circuit board 1 2. The lever 8 is fastened to the potentiometer in such a way that movement of the lever varies the current flowing through the potentiometer 10. The lever extends through the slot 5 in the body 1 into an axially extending groove 6 on the inner surface of the power control collar 2.The length of the slot 5 restricts the movement of the lever 8 so that the lever can only be moved through an angle of 1200 about the longitudinal axis of the body 1 when the collar is rotated on the cylindrical portion 7. The end cap 4, which is removable for connecting a mains lead (not shown) to the terminals 1 6 and 18, contains a threaded portion 20 at its base for mounting purposes. Two screw holes 23 and 25 (see Fig. 4) are provided in the end cap to enable it to be securely fastened to the body 1.

Alternatively, as shown it may be screwthreadedly engaged on the body 1.

Referring to Fig. 3, a circuit diagram of the lamp dimmer circuit is shown. Current for lamp load 22 is typically provided from a 50 cycie 220/240 volt source 24. The amount of current delivered to lamp is determined by controliable, three electrode, alternating current switch 26 available under the trade name of "Triac" or "Quadrac", the latter having a built in diode alternating current switch or "Diac" 28 provided as a trigger for firing the triac in the phase control circuit application.

Where timing capacitor 30, limit resistor 32, and variable 34 comprises the phase control portion of the circuit to regulate the on and off time of the triac switch through the diode trigger, capacitor 36 and inductor 38 are provided for transient suppression, especially the reduction of transients which effect radios connected to the same line as the lamp.

Referring to Fig. 5, there is shown the neutral terminal 1 8 attached to the screw shell 11 by an eyelet fastener. The terminal 1 8 has a flanged base at the mounting end (see Fig. 2) so as to provide a heat sink for the alternating current switch 26.

Instead of providing a screw shell 11, a bayonet type fixture may be provided.

To operate the lampsocket, the power control collar 2 is rotated about the longitudinal axis of the body 1, movement of the collar in the vertical direction being prevented by the ridge 3 on the body 1 and the top of the end cap 4. As the lever 8 extends into the groove 6, rotation of the collar 2 causes movement of the lever 8, which is restricted by the length of the slot 5. Hence, movement of the collar is also restricted. As movement of the lever 8 causes a variation in the current flowing through the potentiometer, it follows that rotation of the collar also varies the current and hence the brightness of a bulb located in the socket. The circuit is arranged so that the full range of current from off to full on is available within the 1200 angle of rotation of the collar.

The circuit itself employs known dimming techniques.

Referring now to Fig. 6, there is shown an adaptor lamp socket which can be placed directly in a standard fitting for a light bulb, the size of the socket being somewhat smaller than that described in the first embodiment. The socket comprises a control collar 43, rotatably mounted on a holder 41. The holder has a two piece moulded body providing a screw shell 62 and a screw base 64. As in the previous embodiment the body 41 can be moulded in phenolic, urea, plastic or other suitable insulating material. A flat recess 44 is indented on the inside of the screw shell 62 in which a metal conductor (not shown) lies.The conductor has at its lower end, a tab bent at right angles to the base of the screw shell, the tab emerging through a hole 46 in a component cavity 42 providing means for current to flow between the screw shell 62 and the screw base 64 and also providing a path for the conduction of heat away from an alternating current switch located in the holder.

As can be seen in Figs. 8 and 9 a stop 50 projects inwardly from the outer sleeve 43 of the lamp socket and locates in recessed channel 48 in the outside wall of the screw shell 62. The channel has a vertical lead-in portion and a horizontal portion extending around a third of the screw shell 62.

In order to minimize the size of the lamp socket a potentiometer component in this embodiment is disposed about the periphery of the control collar so as not to be contained inside the component cavity 42. Two wiper contacts (not shown) for the potentiometer, spaced 1 800 apart extend through holes 60, and 58 in the shell 62.

As can be seen from Fig. 10, a groove 52 is located below the stop 50 in which is placed a resistor strip element (not shown). A shoulder portion 54 on the control collar 43 acts as a mechanical stop which buts against a flange 56 on the body when the holder 41 and sleeve 43 are assembled together. The resistor strip element is formed from a flexible base material such as bakelite which is coated with resistive paint, in such a way that the resistance varies along the length of the strip.

The two pieces of the holder 41 (see figures 7 and 9), when abutted together with various known parts of the control circuitry within cavity 42, are held together by a conductive threaded metal sleeve (not shown) engaging the screwbase 64, and hence projecting tab in the hole 46. The collar 43 is then located on the assembled body, by locating the stop 50 in the lead in portion of the recessed channel 48, and then twisting the collar 43 relative to the body 41, so that the stop engages in the horizontal portion of the channel 48. In this position, shoulder portion 59 will abut the flange 54, and projecting wiper contacts will underlie the resistor strip in the control collar. In this position the top edge of the holder (4) projects beyond that of the collar, and the two parts are held in this assembled relationship by a circlip 71 located in a groove 73 in the holder. In operation the stop 50 moves in the horizontal section of the channel 48 when the sleeve 43 is rotated and the two wiper contacts move along the path of the resistor strip element which has been treated with varying degrees of resistive conductive coating and thus a variable potentiometer is formed so the current flowing to a bulb located in the shell portion 62 can be altered by rotating the collar.

The horizontal section of the channel portion is large enough to allow a 1200 rotation of the sleeve 43. The present invention gives a 3600 approach angle to the control collar. A full control range from off to full-on is provided within a rotation of 1200 which allows full control with a natural wrist movement.

Claims (10)

1. A lampsocket moulded in dielectric material and having a rotatable collar mounted about the periphery of said socket for the purpose of controlling an electronic lamp dimming circuit contained within the body of said lampsocket.

2. A lampsocket according to claim 1 wherein a lever extends from a potentiometer mounted inside the lampsocket and passes through a slot in said larnpsocket body to engage in a groove in said control collar.

3. A lampsocket according to claim 1 or 2 wherein the collar is located between a shoulder on the body of the socket, and a further shoulder provided by a removable end cap.

4. A lampsocket according to claim 1 which is in the form of an adaptor which is provided with a screwbase or bayonet mounting for use in ordinary lampsockets to provide a full range dimming capability.

5. An adaptor according to claim 4 wherein the control collar of the adaptor has a moulded projection extending from the inside thereof to form part of a stop mechanism to limit rotation of said control collar about the periphery of the adaptor, the other part of the stop mechanism being a recessed channel formed in the body of the adaptor in which the projection slides.

6. An adaptor according claim 4 or 5 in which the control collar has a recess containing a resistor strip element thereby utilizing a portion of the inside surface of said control collar as a means of eliminating a potentiometer component from the limited space within the adaptor body.

7. An adaptor according to claim 6 in which the remaining dimmer circuitry is located between the two pieces of the adaptor body, part of said circuitry comprising a centre contact live terminal projecting from the base of the adaptor and two wiper contacts, spaced about 1800 apart about the periphery of the body, said wiper contacts extending through holes in the lampsocket body for contact with the resistor strip mounted in the control collar thereby forming a potentiometer.

8. An adaptor according to claim 5, 6 or 7 in which the adaptor has a two piece moulded body, on the inside of one piece there being provided a recess containing a metal conductor which makes contact with the neutral screwbase of a lampbulb and the screwbarrel portion of the adaptor, the other piece having the recessed channel on its outside surface to receive said projection.

9. A lampsocket substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 5 of the accompanying drawings.

10. A lampsocket in the form of an adaptor substantially as hereinbefore described and as illustrated with reference to the Figs. 6 to 10 of the accompanying drawings.