IMPROVEMENTS IN OR RELATING TO A DEVICE IN LAMPHOLDERS

Abstract: The invention relates to improvements in or relating to a device in a lampholder (1) including a fastening member (2) for fixing the lampholder to a lamp foot, attachment plate or the like, means (3) for retaining a lampholder part (4) to the fastening member (2) and a cord retainer (5) for positionally fixing an electric cord (6) taken to the lampholder (1). The fastening member comprises a fastening plate (2) which, from one side (7) facing away from the side (8) carrying the lampholder part (4) thrusts out a predetermined distance at least two mutually reciprocably movable elongate tongue elements (9) at predetermined mutual spacing, between and along which the cord (6) extends into the lampholder (1), a cap (10) being thrustable over said elements (9) for clamping them against the cord (6), thereby forming a cord retainer for secure positional fixation of the cord (6) to the lampholder (1).

Description: Improvements in or relating to a device in lampholders The present invention relates to improvements in or re¬ lating to a device in a lampholder comprising a fastening member for fixing the lampholder to a lamp foot, attachment plate, cord arrangement or the like, means for fixing a lampholder part on the fastening member and a cord retainer for positionally fixing an electric cord taken to the lampholder. Lampholders on the market today of this type are normally put together from a plurality of different components and these are kept together by thread arrangements as well as separate screws, yokes and the like. Assembly of the components must often take place manually, resulting in very time-consuming work. Attemps with machine assembly result in expensive machine investments as well as relatively large waste or errors, in certain cases, if continuous manufacturing control is not used. Lampholders manufactured by machine have also been found on the market and these have resulted in fires after some time in use, due to the electric conductors having loosened and caused short circuiting, e.g. because the cord retainer was not sufficiently tightly engaged against the electric cord, since unintientional unscrewing had taken place of the screws holding the yoke which fixes the cord, resulting in the ends of the conductors in the cord pulling away from their contacts. In addition, there have been accidents with lampholders which have unthreaded themselves and come away from their fastening member. The object of the present invention is to provide im¬ provements in or relating to a device of the kind mentioned in the introduction, with which the above-mentioned dis¬ advantages in the lampholders of the prior art are completely eliminated, simultaneously as there has been obtained a lampholder which is very reliable in spite of very simple assembly. The characterizing features of the invention are disclosed in the following claims. As a result of the present invention, there has now been provided a lampholder which meets its purposes excellently, while at the same time it is very simple and cheep to manufacture. Screws need no longer be used, and the different components forming the holder are simply assembled and kept together with the aid of snap lock type joints, comprising hooked tongue elements projecting from the different components and coacting with each other. The ready-assembled lampholder cannot be easily taken apart by the user, and thus the risk of accident with screws becoming loose in the lampholder itself is completely eliminated. The invention will now be described below in more detail and with reference to the accompanying drawings, where Fig. 1 is a side wiew, partly in section of a preferred embodiment of the lampholder in accordance with the invention, in its completely assembled state, Fig. 2 is a side wiew, partly in cross section, of the fastening member constituting the central part of the lampholder illustrated in Fig. 1, and which is intended to carry the remaining parts forming the actual lampholder, Fig. 3 is a wiew from above of the fastening member illustrated in Fig. 2, Fig. 4 is a side wiew, partly in cross section, of the lampholder illustrated in Fig. 1, although now turned clockwise 90°, Fig. 5 is a side wiew to an enlarged scale and partly in cross section of the cap illustrated in Fig. 1, Fig. 6 illustrates the cap of Fig. 5 seen from above, and Fig. 7 illustrates the cap in Fig. 5 seen from below. As will be more closely understood from Fig. 1 and 2, a preferred embodiment of the lampholder 1 in accordance with the present invention comprises three main components, which can be assembled together in a simple way simul¬ taneously as the electric cord 6 taken to the lampholder 1 is positionally fixed without using any loose screws or threaded connections, the three parts being as a fastening plate 2 formed fastening member, a lampholder part 4 and a cap 10 constituting a part of the cord retainer 5 of the lampholder " 1. The fastening plate 2 is intended for fixing the lampholder 1 to a lamp foot, an attachment plate, a cord arrangement or the like, and said fastening plate 2 has on one side 8 means in the form of hooked snap tongues 3 which are integral with the fastening plate 2, and project out from its periphery for retaining the lampholder part 4 to the fastening plate 2. At least two elongated tongue elements 9 project out a predetermined distance from the opposing side 7 of the fastening plate 2, and are intended to retain between them the electric cord 6 to the lampholder 1. The two tongue elements 9 are mutually parallel and spaced at a predetermined spacing substan- tially corresponding to the thickness of the electric cord 6 which is used. In addition, they can move mutually reciprocally with spring bias, and are provided with a cap 10 which can be thrust over them for clamping them against the electric cord 6 between them, such as to form the cord retainer 5. At the closed end 12 or bottom 21 of the cap 10 there is an opening 11 for the passage of the cord 6, and on its inside near its mouth 14 the cap 10 has an abutment 13 for coaction with a corresponding abutment 15 on the outside of the tongue elements 9. When the cap 10 is urged along the cord 6 and over the tongue elements 9, these two abutment parts 13 and 15 coact such as to snap the cap 10 in place when it has been completely thrust over the elements 9, while at the same time clamping the cord 6 between these elements 9. The tongue elements 9, which are preferably integrally made with the fastening plate 2, are provided with ridges 16 on their opposing faces transverse to their longitudinal direction for increasing the friction against the sheath of the cord 6. The cap 10 has at least two elongated slots 17, which depart from its upper edge 18 at its opening 14, and extend a short distance in its longitudinal direction. These slots 17 give the cap 10 a sprung zone which facilitates thrusting it over, and positionally fixing it to, the tongue elements 9. To provide a clamping effect against the cord 6 the elements 9 and cap 10 can have mutually coacting tapering surfaces in a region 20 situated on the outside of the elements 9 and on the inside of the cap 10 along the part between the bottom 21 of the cap 10 and the end of the slots 17 Λ just before the central part of the cap 10. The fastening plate 2 has a groove 19 round its circumference for fixing the lampholder 1 to a lamp foot or an attachment plate. For more secure fastening of the electric cord 6 in the cord retainer 5, the ridges 16 on the respective element can be mutually displaced in the longitudinal direction of the elements 9. The hooked snap tongues 3 for fastening the lampholder part 4 have hookes 25 projecting in mutually opposing directions for engagement against abutments 24 formed in recesses 22 on the lampholder part 4. It is thus not necessary, as was previously usual, to screw the lampholder part 4 down with a thread connection, and it only needs to be pressed in its axial direction towards the fastening plate 2 until the parts 24 and 25 snap lock into each other. The lampholder part 4 is assembled in the following manner. The cap 10 is first pushed over the electric cord 6 with its mouth 14 towards the end of the cord to be fixed in the lampholder 1. The ends of the cord conductors 6 are then thrust into the terminals in the lampholder part 4, and these terminals can have a structure automatically locking the conductor ends. When this has been done, the lampholder part 4 is thrust down on to the fastening plate 2 and locked, after which the cap 10 is thrust along the cord 6 and over the tongue elements 9 until it is snap locked against the fastening plate 2, the cord 6 now being effectively, positionally fixed in the cord retainer 5. The assembly can thus be carried out entirely without the use of tools, while permanent fixing of the different parts is achieved, i.e. the parts cannot be dismantled after being assembled. The problem of the user taking apart lampholders so that accidents can happen has thus been solved. By the simple and inexpensive structure in accordance with the invention, this lampholder can be regarded as a disposable article, to be replaced by a new one when it is no longer serviceable.

Claims: Claims 1. Improvements in or relating to a device in a lamp¬ holder including a fastening member (2) for fixing the lampholder (1) to a lamp foot, attachment plate, cord arrangement or the like, means (3) for fastening a lamp- holder part (4) to the astening member (2) and a cord retainer (5) for positionally fixing an electric cord (6) taken to the lampholder (1) , said fastening member (2) comprising a fastening plate (2) which, from the side (7) opposite to the side (8) carrying the lampholder part (4), thrusts out at least two elongate tongue elements (9) a predetermined distance, the elements being mutually, reciprocably movable at given mutual spacing, the electric cord (6) extending into the lampholder (1) between and along said elements, over which a cap (10) having an opening (11) at its closed end (12) for the passage of the cord (6) can be thrust or clamping the tongues (9 ) to¬ gether in a direction towards the cord (6), characterized in that the cap (10) includes at least one abutment part (13) on its inside in the vicinity of its opening (14) for coaction with at least one correspondingly formed abutment part (15) on the outside of the tongue elements (9 ) for providing a permanent snap lock of the cap (10) when it is completely thrust over the tongue elements (9) for achieving a secure positional fixation of the cord (6) in the lampholder (1). 2. Device as claimed in claim 1, characterized in that the sur aces of the tongue elements (9 ) acing towards the cord (6) have ridges or projections (16) transverse to their longitudinal direction for increasing friction against the sheath of the cord (6). 3. Device as claimed in claim 1, characterized in that at least two slots (17) extending from the edge (18) forming the mouth (14) of the cap (10) a short distance in the axial direction of the cap (10) such as to form a spring-biassed zone (19) for facilitating thrusting the cap over, and positionally fixing it to the tongue elements (9). 4. Device as claimed in claim 1, characterized in that the fastening plate (2) has a groove (19) round its circumference for fixing the lampholder (1) to a lamp foot or an attachment plate. 5. Device as claimed in claim 1, characterized in that the tongue elements (9) and the cap (10) have mutually coacting tapering surfaces in a region (20) opposite the projections (16) on the elements (9) on their outside and on the inside of the part of the cap (10) between the bottom (21) of the cap (10) and the end of the slots (17) for providing a clamping effect against the cord (6) when the cap (10) is snap locked into position. 6. Device as claimed in claim 1, characterized in that the means keeping the lampholder part (4) against the fastening plate (2) comprise at least two hooked snap lock tongues (3) integral with the fastening plate (2) and upstanding from its surface (8), said tongues being adapted for coacting with recesses (22) in the part (23) of the lampholder part (4) facing towards the fastening plate (2), said recesses (22) include an abutment (24) for coaction with the hooks (25) projecting from the snap lock tongues (3).

Inventors: HURTIG GOERAN, SKILLIUS HANS, HURTIG, GOERAN, SKILLIUS, HANS
Applicants: ARTILUX AB
Application year: 1988
Main classification: F21V19
IPC codes: F21V19, F21V27, H01R13, H01R33