Assembly of a lamp holder and a support of a lighting unit for conductively fitting a lamp, of the low-voltage halogen-type, provided with two conductive pins, in which the conductive parts of the lamp holder themselves constitute the lamp holder and are separated from each other by an insulator - in other words, the entire body of the lamp holder, except for the insulator, is conductive - and are conductively fixed to the support of a lighting unit, means being provided in or on the two conductors for the conductive and firm fixing in or on these conductors of the conductors of the lamp to be fitted, in which one conducting lamp pin is smaller than the other and is - preferably entirely - enclosed in the other conductor of the lamp holder, and that the support of a lighting unit is attached to - or partially attached within - the large conductor, and the conductors of the support of a lighting unit are - preferably in the lamp holder - conductively connected to the conductive parts of the lamp holder and thus provide a good conductive contact with the lamp,
An assembly of this type is known from US-A-2 101 277.
This assembly has a number of practical disadvantages.
These disadvantages are connected to the fitting of the conductors of the lamp holder, which is the more a problem when the lamps are changed or interchanged. The object of the invention is to remove these disadvantages and provide an assembly of the type described in the preamble, which can be easily changed or interchanged.
This object is reached by the invention, in that for attaching the two conductors of the lamp holder to each other, one conductor (the small one) fits very tightly, with a so-called interference fit, in the insulator, which encloses the conductor and fits very tightly, with a so-called interference fit, in the other, large conductor, which fully encloses the insulator, thus there is no need to use any other fixation and/or locking materials.
According to a preferential embodiment of a support of a lighting unit for the use in the assembly of claim 1, for low voltage lamps, the body of the support of the lighting unit is one of the two conductors, and the other conductor passes through that body, preferably in the form of a live wire insulated from the body. The opening in the large conductor, which is intended for accommodating the small conductor which is equipped with the insulator or the small conductor, or both is (are) provided with a beveled edge at the edges closest to the other conductor, such that the distance between the two conductors is at least as large as the standards laid down for this (IEC 598, inter alia so-called creepage distances).
Advantages of the invention are the following:
A description will now be given of an embodiment of the present invention for a low-voltage (halogen) lamp with a bi-pin base (for instance, type GX 5.3) which is to be fitted at right angles to the support of a lighting unit. Figure 1 shows the lamp holder described in section and figure 2 in perspective. The figures 3 and 4 are a plan view and a side view of a possible application of the lamp holder described in combination with a support of a lighting unit of special shape.
The lamp holder consists of two conductors (1, 2) and an insulator (3), and for fixing one to the other there is no need to use any fixation and/or locking materials, because one conductor (2) is smaller than the other (1) and fits entirely and very tightly in the insulator (3), which fully encloses the conductor (2) and fits entirely and very tightly in the other conductor (1), which fully encloses the insulator (3), in such a way that the two ends of all three components coincide precisely, without any of them projecting more than the other two. To minimize the dimensions, the ends of the hole in the conductor (1) can be provided with a bevelled edge (14), as a result of which the distance between the end of the insulator (3) and the end of the conductor (1) is equal to the thickness of the insulator, so that the legal requirements with regard to the distance between the two conductors is complied with, whereas the insulator can be thinner than that distance, and yet the two conductors (1, 2) need not be insulated from each other in some other way.
For the conducting fixation of the conducting lamp pins (5) of the lamp (4) the lamp holder has certain provisions, which here have the form of a socket (6) in each conductor (1, 2) of the lamp holder. The lamp pins (5) are locked in the sockets (6) with the aid of screws for which provisions have been made in the lamp holder (7). The presence of the locking screws ensures a secure and conducting accommodation of the lamp (4) in the lamp holder. The length of the screws used is determined by the thickness of the small conductor (2): the screw must not connect up with the other conductor (1) and must have sufficient material in the small conductor (2) to be securely fixed.
The lamp holder is attached to a support of a lighting unit, of which the body (8) is one of the conductors. The other conductor (9) of the support of a lighting unit passes throught the body (8) and is separated therefrom by an insulation (10), for instance copper wire with an insulating sheath. In the present case the lamp holder has been mounted perpendicular to the support of a lighting unit. To this end the two conducting parts of the lamp holder (1 and 2) are provided with an opening (11 and 12, respectively) to accommodate the conductors of the support of a lighting unit (8 and 9, respectively). For the same reasons, both of them are locked in position with the aid of, for instance, screws, for which provisions (13) have been made in the holder. The live connection between the small conductor (2) and the wire (9) is effected by the screw (13), which locks the wire (9) by turning it through the insulation (10).
Attachment and locking of the lamp holder on the support of a lighting unit is effected by means of the attachment and locking means used for the live connection (13 on 8 and possibly 13 on 9). To ensure the good conductive contacts that are so important in this type of lighting it is advisable to make the fits as tight as is practically possible, which also applies, where necessary, to all the other attachments, so that firm contacts are ensured. Of course, this is also true of any other means of attachment.
If the lamp is to be placed in line with the support of a lighting unit, the fitting openings (11, 12) and their means of attachment (13) change places, and the small conductor (2) of the lamp holder and the insulator (3) need not extend through the entire length of the large conductor (1), but only, for instance, to a point halfway.
If it is desired to keep the dimensions of the entire lamp holder as small as possible, then the small conductor (2) is probably best mounted excentrally in the large conductor (1). Further alternatives can, of course, be found in the shape (six-angled, square, etc.), the exact location of the possibly present bevelled edge (on both halves of the holder or on one of the two, or on neither, or on only one of the ends of the lamp holder), the way in which the large conductor encloses the small one (entirely, one of them projecting from the other, the small conductor being enclosed only partially in the large one, etc.) etc.
When the locking mechanism (13) of the lamp holder on the body (8) is extended to a point outside the holder, there is obtained a positioning rod (16), which can be manipulated with the fingers and repeatedly locked, and with which the locking can be temporarily removed, so that the holder can be turned round the body (8), provided that the fit of the holder on the body (8) permits this. For this lastmentioned purpose use can be made of a cylindrical holder clamp (15), which is clamped round the end of the body and fits tightly in the holder. It is provided with a groove round its exterior surface at the locking means (13 or 15), and also serves as an extra lock when the holder is turned, because the locking remains within the groove when the lock is partially removed, and it is impossible for the holder to come off the body (8).
If the body (8) is bent at a point (17) just before the lamp holder, the holder can be fastened in line with the body and still have a point of attachment which is perpendicular to the main direction of the body (8). In addition to having an aesthetic advantage, this shape ensures that the support of a lighting unit - for instance, when used horizontally - is suspended in equilibrium when the shape of the body is a downwardly bent one (for instance, the holder is to be positioned lower than the point of attachment of the entire support of a lighting unit): since the holder extends in line with the body (8), the support of a lighting unit will not sag under the influence of gravity, as happens with a horizontal attachment without bend (17), in which case the support of a lighting unit may sag down on the side where the lamp holder is attached.
The bend (17), in cooperation with the positioning rod (16) also prevents the holder from getting turned round further and further (for in that case the wire in the support of a lighting unit might break); when the positioning rod (16) is turned round, it hits the body (8) and is blocked in its way, so that the holder can turn through an angle of just under 360°.